Alexandra Gorringe 1265587 MESci Dissertation

Spatial and temporal distribution of sediment flux

and nutrient bioavailability in a High-Arctic glacial

environment, Svalbard

A Thesis

Submitted to Cardiff University School Office

in partial fulfilment of the requirements for the degree

of Master of Science in Environmental Geoscience

In the Department of Earth and Ocean Sciences

By

Alexandra Gorringe

Cardiff University

Main Building, Cardiff

CF10 3XQ

April, 2016

1 | P a g e

DECLARATION

This work has not previously been accepted in substance for any degree and is not being

concurrently submitted in candidature for any degree.

Signed: ________________________________ (candidate)

Date: __________________________________

STATEMENT

This dissertation is being submitted in partial fulfilment of the requirements for the degree of

Master of Earth Sciences.


Date: __________________________________

STATEMENT

This dissertation is the result of my own independent work, except where otherwise stated.


Date: __________________________________

2 | P a g e

ABSTRACT

The importance of glaciers and ice sheets as major sediment and nutrient fluxes to marine and

coastal environments, has been overlooked for many years. Recent field studies have shown

that the contribution of nutrient export to oceans, particularly with regard to phosphorus and

iron fluxes, are significantly greater than originally anticipated. As a result, the sediment flux

of glacial valleys and large ice masses, needs to be considered as an important control on

nutrient export to polar oceans. Nutrient flux into the marine environment provides

phytoplankton with; carbon, nitrogen and phosphorus, as well as other potentially limiting

nutrients, such as iron and zinc, promoting photosynthesis and biomass production. An

increase in photosynthetic activity, not only promotes biodiversity (as phytoplankton form the

base of oceanic food webs), but also generates significant carbon dioxide draw-down, with

the potential capacity to reduce the effects of climate change. However, the mechanics and

dynamics of these fluxes and their inter-relationships are still relatively unknown. Attempts

to understand glacial contributions to these sediment and nutrient fluxes in high-sediment

yield locations (temperate glaciers) have begun to dominate the literature, however, very few,

if any studies, investigate the spatial and temporal variations of these fluxes in a polythermal

glacial valley. This project is the first of its kind to investigate sediment flux throughout the

entirety of a polythermal glacial valley, Endalen, in High-Arctic Svalbard, therefore, the aims

and hypotheses of this project remain investigative and relatively open-ended. Analysis of

suspended sediment and nutrient fluxes in the valley showed that, whilst there are variations

in sediment quantity between sample sites, the overall flux does not differ greatly along the

valley. Sediment flux remains relatively constant throughout the valley, as does nitrogen and

carbon ratios, indicating that samples taken from any proglacial locality (downstream of the

tributary draining Nordre Bayfjellbreen) in the Endalen glacial valley, will be representative

of the whole valley. Results from temporal distribution analysis have highlighted the

importance of glacial meltwater runoff, not only as a medium for transporting sediment (and

therefore sediment-adsorbed nutrients) to downstream ecosystems, but also as a critical

variable for determining the rates of erosion and production of sediment, as well as ion form

and glacial hydrochemistry, in polythermal glacial valleys.

3 | P a g e

Contents

DECLARATION................................................................................................................................... 1

ABSTRACT ........................................................................................................................................... 2

List of Figures ........................................................................................................................................ 5

CHAPTER 1 INTRODUCTION ......................................................................................................... 7

1.1 Research significance ..................................................................................................................... 7

1.1.1 The role of glaciers in the global sediment budget ................................................................. 7

1.1.2 The role of glaciers in global biogeochemical cycles ............................................................. 8

1.1.3 The relevance of glacial sediment flux research ..................................................................... 9

1.2 Research Objectives ................................................................................................................ 10

1.2.1 Investigating sediment flux changes ..................................................................................... 10

1.2.2 Investigating nutrient content and bioavailability ................................................................ 11

1.3 Hypotheses ............................................................................................................................... 11

1.4 Thesis Outline .......................................................................................................................... 12

CHAPTER 2 LITERATURE REVIEW ........................................................................................... 13

2.1 Glacier thermal regimes ............................................................................................................... 13

2.1.1 Temperate glaciers ....................................................................................................................... 14

2.1.2 Cold-ice glaciers .......................................................................................................................... 15

2.1.3 Polythermal glacier mechanics .................................................................................................... 15

2.1.3.1 Englacial Drainage ................................................................................................................... 15

2.1.3.1.1 The development of englacial conduits ................................................................................. 17

2.1.3.1.2 Crevasse-base incision and Hydrofracturing ........................................................................ 17

2.1.3.2 Subglacial drainage .................................................................................................................. 18

2.1.3.2.1 Seasonal variation in subglacial outflow ............................................................................... 19

2.1.3.2.2 Annual water storage and release ......................................................................................... 20

2.2 Glacier Hydrochemistry ............................................................................................................... 21

2.3 Glacial sediment erosion ............................................................................................................... 22

2.3.1 Physical erosion ........................................................................................................................... 22

2.3.2 Chemical weathering and erosion ............................................................................................... 24

2.3.3 Microbial mediation of subglacial reactions ............................................................................... 26

2.3.4 Climate change and future implications ...................................................................................... 27

2.4 Sediment transport ....................................................................................................................... 27

2.4.1 Suspended sediment flux .............................................................................................................. 28

2.4.2 Nutrient transport and suspended sediments in glacial meltwaters ............................................ 30

2.4.3 The role of suspended sediment for global element fluxes ........................................................... 30

4 | P a g e

2.4.4 Inorganic nutrients and minerals (phosphorus and iron) ............................................................ 32

CHAPTER 3 METHODOLOGY ...................................................................................................... 35

3.1 Site description .............................................................................................................................. 35

3.1.1 Bogerbreen thermal regime ......................................................................................................... 37

3.1.2 Lithology and sediments .............................................................................................................. 38

3.1.3 Geochemical interactions ............................................................................................................ 38

3.1.4 Sediment yields in the Endalen glacial valley .............................................................................. 38

3.2 Data collection ............................................................................................................................... 39

3.3 Sediment analysis (weighing) ....................................................................................................... 40

3.3.1 Wet sediment ................................................................................................................................ 41

3.3.2 Dry sediment ................................................................................................................................ 41

3.4 Ion chromatography (Major ion analysis) .................................................................................. 42

3.5 Elemental analysis ......................................................................................................................... 43

3.5.1 Sediment preparation for decalcification .................................................................................... 43

3.6 Phosphorus extraction .................................................................................................................. 45

3.6.1 Extraction method ........................................................................................................................ 46

3.6.2 Colourimetric determination of phosphate .................................................................................. 47

3.6.3 Combined reagent ........................................................................................................................ 48

CHAPTER 4 RESULTS AND DISCUSSION .................................................................................. 49

4.1 Sediment analysis .......................................................................................................................... 49

4.1.1 Spatial variation in suspended sediment ...................................................................................... 49

4.1.2 Temporal variation in suspended sediment ................................................................................. 52

4.1.3 Discussion of suspended sediment flux variability and recommendations for study improvements

.............................................................................................................................................................. 55

4.2 Elemental analysis ......................................................................................................................... 56

4.2.1 Spatial trends in elemental content of suspended sediment ......................................................... 57

4.2.2 Temporal variation in elemental content of suspended sediment ................................................ 58

4.2.3 Carbon:Nitrogen ratios and their implications ........................................................................... 59

4.3 Ion chromatography ..................................................................................................................... 61

4.4 Phosphorus analysis ...................................................................................................................... 65

4.4.1 Particulate phosphorus concentration at each site (spatial distribution) .................................... 67

4.4.2 Phosphorus concentration through time (temporal distribution) ................................................ 70

4.4.3 Discussion of refractory and moderately labile P variability ...................................................... 71

CHAPTER 5 SUMMARY .................................................................................................................. 73

5.1. Summary of suspended sediment flux ........................................................................................ 73

5.2. Summary of elemental nitrogen and carbon concentrations ................................................... 73

5 | P a g e

5.3 Glacial hydrochemistry and major ion analysis summary ....................................................... 74

5.4 Summary of particulate phosphorus flux ................................................................................... 74

5.5 Recommendations for project improvements and further analysis ......................................... 75

REFERENCES .................................................................................................................................... 76

ACKNOWLEDGEMENTS ............................................................................................................... 91

APPENDIX .......................................................................................................................................... 92

List of Figures

1. Conceptual model of global sediment cycles (Tranter, undated)………………….......8

2. Sediment fluxes from glacier runoff and rivers (Tranter, undated)……………….......8

3. Glacier hydrology for temperate glaciers (Irvine-Fynn, et al. 2011)..………………14

4. Schematic mechanisms of englacial drainage (Irvine-Fynn, et al. 2011)...…………16

5. Potential outflow routes in polythermal glaciers (Irvine-Fynn, et al. 2011)...………19

6. Model of glacial erosion and thermal regime (Singh, et al. 2011)……...……………23

7. Conceptual model glacial hydraulics and bacterial activity (Hodson, et al. 2008)…..26

T1. Suspended sediment transport, Svalbard (Bogen and Brønsnes, 2003)……...………29

E1. Anoxic production of ferric oxyhydroxide and sulphates……………………………33

E2. Oxic production of ferric oxyhydroxide and sulphates………………………………33

8. Map of Endalen glacial valley………………………………………………………..35

9. Satellite images of the study area…………………………………………………….36

10. Aerial 3D images of catchments near Endalen……………………...……………….36

11. Sample site localities…………………………………………………………………37

12. Photographs of the study area………………………………………………………..39

T2. Sample frequencies from the two main collection periods………………………….39

13. Bagged wet sediment samples……………………………………………………….40

14. Coarse and fine sediment filters after oven drying…………………………………..42

T3. Major anion standards……………………………………………………………….43

T4. Major cation standards………………………………………………………………43

15. Sediment preparation for decalcification……………………………………………44

16. Sediment decalcification process……………………………………………………44

T5. Standard phosphorus solutions……………………………………………………...47

17. Average spatial sediment flux…………………………………………………….…49

18. Visual representation of valley sediment flux……………………………………….50

6 | P a g e

19. Sample frequencies (sediment – spatial distribution)………………………………..51

20. Average suspended sediment yield (spatial)…………………………………………52

21. Sample frequencies (sediment – temporal distribution)……………………………..53

22. Average suspended sediment yields over time………………………………………53

23. Sample frequencies (sediment – total temporal distribution)………………………..54

T7. Average % C and % N concentrations (temporal distribution)……………………...54

24. % C and % N spatial distribution…………………………………………………….57

25. % C and % N relative to one another……………………………………………..….59

26. N:C ratio spatial distribution…………………………………………………………60

27. Major cation concentrations for site 4………………………………………………..61

28. Major cation concentrations (temporal comparisons)………………………………..62

29. Gruvendalen runoff source…………………………………………………………...62

30. Major anion concentrations (temporal comparison)…………………………………63

31. Spatial and temporal distribution of sulphate ions…………………………………...65

32. Sample frequency (spatial phosphorus distribution)…………………………………66

33. Sample frequency (temporal phosphorus distribution)………………………………66

34. Phosphorus concentration for each extractant phase (spatial distribution)…………..67

35. Average phosphorus concentration for each sample site…………………………….68

36. Average phosphorus concentration for each sample period…………………………70

37. Average phosphorus concentration (spatial and temporal distribution)……………...71

7 | P a g e

CHAPTER 1 INTRODUCTION

This chapter:

Highlights the research significance of this project

Briefly describes glacial contribution to global cycles, namely; global sediment

budgets and global biogeochemical cycles

Outlines the research objectives and proposed hypotheses of this investigation

Provides a general thesis outline

1.1 Research significance

The forefront of current glacial research highlights the importance of glaciers in two main

spheres; indicators of a changing climate (Haeberli, et al. 2007; Vuille, et al. 2008; Scherler,

et al. 2011) and glaciers' contribution to global cycles, namely; sediment budgets (Einsele,

1992; Wasson, 2003) and biogeochemical cycles (Anesio, et al. 2009), the latter of which is

the focus of this project.

1.1.1 The role of glaciers in the global sediment budget

Research into suspended sediment flux from glacial regions has highlighted the importance of

glaciers in their contribution to the global sediment budget (Bogen and Brønsnes, 2003 and

Hodgkins et al., 2003). Global sediment budgets in the past did not take into consideration

the impact of glacial erosion in high-latitude landmasses, particularly Greenland and

Antarctica, because the data is seasonal and scattered and represents only a few months of the

year. Estimates of contributions to the global sediment budget are also difficult to quantify.

Whether by riverine, glacial or aeolian supply, due to the high spatial and temporal variability

of clastic fluxes, it would require numerous samples to be taken over prolonged periods of

time and at many geographically diverse locations (Raiswell, et al. 2006). However, in the

last two decades, estimates of glacial contributions to the global sediment budget have been

presented based on analyses of glacial sediment fluxes. The estimates range from rates of

10,000 tonnes of sediment per kilometre squared per year (Milliman and Farnsworth, 2013)

to total global sediment flux contributions ranging from 800 to 5000 tetragrams per year (fig.

1 and 2). Whilst the exact amounts or percentages of glacial contribution to the global

sediment budget are unknown, the estimates suggest (and many authors support the notion)


8 | P a g e

that glacially derived and transported sediments form a significant component of the global

sediment budget (Benn and Evans, 2010).

Figure 1 | Conceptual model of the global sediment cycle with estimate sediment budget fluxes (Tranter, undated).

Figure 2 | Sediment fluxes from glacier runoff and rivers (Tranter, undated).

The mass transportation of suspended sediment to coastal environments brings nutrients to

marine environments, affecting the biogeochemistry of coastal ecosystems.

1.1.2 The role of glaciers in global biogeochemical cycles

Studies by Hawkings et al. (2016) have highlighted the importance of the sediment fraction

in glacial runoff, not only in its contribution to the global sediment budget, but also to global

biogeochemical cycles. Their research found that the sediment may act as a more effective

transporter of nutrients to marine ecosystems than just glacial meltwaters alone. As a result of

large influxes of nutrient-rich sediments (high is phosphorus, iron and silica) into the polar


9 | P a g e

oceans, microorganisms and primary producers, such as phytoplankton, gain additional

‘food’ sources, promoting ecosystem health. More nutrients available for phytoplankton (the

base of the food chain) results in an increase in total mass (providing food for other species

higher up in the food chain). An additional benefit of increased plankton activity promotes a

significant draw-down of atmospheric CO2 (Hodson et al., 2005 and Hodson et al., 2008).

This sediment export and nutrient flux into the ocean challenges traditional notions by stating

that ice sheets and glaciers are important in biogeochemical cycles compared to other

terrestrial environments (Hawkings, 2016).

However, the process of glacial nutrient fertilisation to the marine environment, as well as

sediment flux within a glacial valley, is poorly understood. Additional research attempts have

focused their efforts on understanding sediment flux and characteristics in localised

individual areas of a glacial valley (Hallet, et al. 1996). However, this project aims to

examine sediment and nutrient characteristics across the entire traversable length of a non-

temperate glacial valley in High Arctic Svalbard. In doing so, it will enable a better

understanding of; the spatial and temporal distribution of sediment within the glacial valley,

the availability of nutrients to microorganisms in downstream environments, and the potential

impacts of these nutrients on the dynamics of micro-communities in terms of; availability,

activity and structure.

1.1.3 The relevance of glacial sediment flux research

The primary focus of this project is to gain a greater understanding of the sediment flux in a

High-Arctic glacial valley from a predominantly cold-based polythermal glacier. I also aim to

attempt to understand the interactions between suspended sediment flux and particulate

nutrients characteristics, particularly with respect to carbon, nitrogen, phosphorus and major

ions. However, there are other important reasons for increasing one’s understanding of the

glacial sediment and nutrient fluxes.

Suspended sediment export and glacial meltwater runoff contribute significant fluxes of

nutrients (particularly phosphorus [Hodson, et al. 2004] and iron [Raiswell, et al. 2006] to

coastal Polar oceans, fuelling plankton growth and enhancing localised oceanic biodiversity.

However, the proportions of these fluxes are a recent discovery and little is known about the

dynamics associated with them and the interactions of different components both in the


10 | P a g e

terrestrial (from source to sink) and marine environment. Attempting to understand the spatial

and temporal distribution of sediment and nutrients across the entirety of a polythermal

glacial valley, therefore, will help provide some understanding in flux dynamics and

interactions.

Additionally, there are anthropogenic implications to consider. High Arctic environments,

such as Svalbard, are highly sensitive to disturbance from human activity, so it is important,

for management purposes, to understand erosion activity and sediment flux (Bogen and

Bønsnes, 2003). Also, anthropogenic release of phosphorus and nitrogen sources to coastal

environments can sometimes have catastrophic effects on marine life, leading to toxic algal

blooms and even red tides (ref). Whilst limiting these releases is of upmost importance, it is

also important to build our understanding of natural responses to nutrient export from glacial

runoff in sensitive Polar environments, in order to understand how the coastal fjord biota,

may respond to larger exports of nutrients.

Evidence of increased carbon dioxide (CO2) intake already suggests that increasing nutrient

export (iron, phosphorus and nitrogen) to polar oceans could be a potential technique to

counter, or at least limit, the effects of accumulating anthropogenic CO2. However,

understanding the thresholds associated with this delicate balance is crucial.

1.2 Research Objectives

There are two main components to this research project. The first is to investigate how

sediment flux changes along a non-temperate glacial valley through space and time. The

second is to determine how the nutrient content of the transported sediment within the valley,

impacts downstream ecosystems.

1.2.1 Investigating sediment flux changes

Understanding the spatial and temporal distribution of sediment along the entirety of a glacial

valley will grant a significant insight into sediment flux within non-temperate, High-Arctic

environments. The aim is to investigate whether there is a pattern to suspended sediment

distribution within the valley and whether the flux changes through space and time.


11 | P a g e

Measuring the wet and dry sediment samples taken from different sites over time, will show

if there is (or is not) a distribution pattern.

1.2.2 Investigating nutrient content and bioavailability

The second component of this research project is to investigate the nutrient characteristics

within the suspended sediment. Samples of filtered suspended sediment, as well as samples

of glacial meltwater, are analysed to determine; what major ions are present in the water

column (using ion chromatography) and what percentage of Redfield Ratio components

(carbon, nitrogen and phosphorus) are adsorbed to sediment particles (using elemental

analysis and phosphorus extraction). The phosphorus extraction process will also show

whether phosphorus can be made available for plankton uptake (bioavailable).

Combining results from the sediment distribution analysis and the elemental analysis, it may

be possible to determine whether components such as; major ions, carbon, nitrogen and

phosphorus, have maintained levels throughout the valley (are not used up by organisms) or

whether there is a correlation between sediment locality and nutrient content. Additionally,

phosphorus extraction will allow me to determine the quantity of phosphorus adhered to the

sediment particles as well as showing how much bioavailable phosphorus (NaOH-P) is

present. The presence of NaOH-P will suggest nutrients are bioavailable for microorganisms

in downstream environments and support the theory that sediment flux and glacial nutrient

transport are important contributors to global sediment budgets and biogeochemical cycles.

1.3 Hypotheses

Site-specific studies of sediment characteristics have been conducted in non-temperate glacial

valleys in the past in order to better understand the role of major ions and nutrients in

biogeochemical cycles. Additionally, temperate glaciers, in milder climates, with high

sediment flux, have been extensively studied for their contribution to the global sediment

budget. However, there has been minimal to no studies conducted, so far, on non-temperate

polythermal glaciers, that examine sediment flux along the entirety of a glacial valley. This

project will be one of the first to do so. Therefore, the hypothesis is investigatory, stating that

there will be an observable trend in sediment flux along the Endalen glacial valley which will


12 | P a g e

ultimately impact nutrient delivery to downstream ecosystems. It is uncertain whether there

will be a change or not in the variables through space and time, however, the aim of the

investigation is to see whether there is a change or not.

1.4 Thesis Outline

Chapter two presents a literature review on the main components of glaciology relating to this

project. It underlines the principles of glacier mechanics, with particular regard to the thermal

regime of glaciers, and focuses on the characteristics of polythermal glaciers with respect to

sediment; production, transport and deposition. Chapter two also summarises variations in

suspended sediment flux from studies in temperate glaciers. The chapter finishes with an

outline of the importance of phosphorus and other nutrients in glacial suspended sediments,

their occurrence within current glacial systems and a reiteration of their involvement in

biogeochemical cycles, particularly in downstream environments.

Chapter three, the methodology, introduces the project site, Endalen, Svalbard and how

samples were collected. It also describes the methodologies of each of the techniques used to

analyse the data and prepare the sediment samples, including; sediment weighing, ion

chromatography, elemental analysis and phosphorus extraction.

Chapter four provides an analysis of the data, using linear regression to compare trends

between glacial runoff components (nutrient concentrations and suspended sediment) and

how they vary through space and time. Chapter four also discusses what the data shows,

suggests reasons based on the literature as to why the data has presented itself in that way,

and finally, concludes with discussing implications of variabilities in fluxes.

Chapter five summarises the thesis with several main concluding paragraphs, including

recommendations for improvement of this study and future research similar to this research

project.


13 | P a g e

CHAPTER 2 LITERATURE REVIEW

This chapter aims to:

Introduce basic principles in glacier hydrochemistry, as well as examine the

literature on glacier types and their thermal regimes, with particular focus on

polythermal glacier mechanics.

Discuss glacial meltwater characteristics in supraglacial, englacial and subglacial

environments

Elaborate on how glacial meltwater contributes to different types of sediment erosion

and erosion rates.

Outline sediment transport in proglacial valleys and the nutrients associated with

suspended sediment flux

Discuss the importance of nutrients (carbon, nitrogen, phosphorus, iron and

silicates) to coastal and downstream ecosystems

2.1 Glacier thermal regimes

The glacial contribution to the global sediment budget was noted in chapter one, however

these contributions vary depending on glacier type. The identified global glacier types have

led to the development of a scale, in which, at one end are the cold-ice glaciers, and at the

other, the temperate glaciers (Hodson, 1994). Glaciers belonging to the opposite ends of this

scale have certain characteristics that differ drastically from one another, most notably, the

thermal regime. A glacier’s thermal regime is considered one of the most important factors in

determining subglacial processes. The thermal regime is a function of ice temperature (which

in turn is a function of the temperatures of the air and ground [geothermal potential]) and ice

pressure (Davies, 2014). The different thermal regimes of glaciers determines the amount and

locations of meltwater within the glacier. As a rule, polar ice masses are interlaced with

drainage systems throughout their structure; at the surface (supraglacial), internally

(englacial) and at the base of the ice (subglacial). The role and activity of each of these

meltwater subsystems varies in space and time (Irvine-Fynn, et al. 2011).

Studies by Copland et al. (2003) and Rippin et al. (2005) have highlighted the importance of

subglacial meltwater flow (also known as basal flow) in reducing basal traction. The presence


14 | P a g e

and amount of subglacial meltwater also controls the major processes associated with

sediment-related transport. Sediment entrainment, transfer and deposition refers to the debris

that is incorporated into the glacier (into the base or on the surface) and then modified and

deformed during glacial flow and then deposited after reworking (Singh, et al. 2011). A

glacier’s thermal regime also plays an important role in glacier velocities and ice deformation

(Davies, 2014).

2.1.1 Temperate glaciers

Glaciers in temperate regions, such as the Alps, are subject to milder temperatures (compared

to polar regions) and contain large volumes of ice, which increase the pressure at the base of

the glacier, generating heat, inducing melt and facilitating basal movement (Benn & Evans,

2010; Cuffey and Paterson, 2010) (fig. 3). As the glacier moves, underlying debris may pose

an obstacle to ice, causing melting and refreezing in lee of the object (Davies, 2014). In doing

so, debris is readily entrained into basal ice layers. As the debris is moved along, it is eroded

and scraped against the bedrock as well as other debris components in and around the base of

the glacier. As a result, temperate (also known as ‘wet-based’) glaciers have the potential to

erode and transport large volumes of sediment, depositing them in landforms such as;

moraines, drumlins and scoured bedrock (Goodsell et al. 2005; Evans et al. 2006; Davies,

2014). Erosional processes could further break and grind down the rock debris into smaller

particulates such as fine silts and clays that form suspended sediment in subglacial meltwater

flows.

Figure 3 | Glacier hydrology for temperate glaciers (Irvine-Fynn, et al. 2011).


15 | P a g e

2.1.2 Cold-ice glaciers

Alternatively, cold-ice glaciers (also known as ‘cold-based glaciers’ or ‘dry-based glaciers’)

have their basal part (at the base of the glacier) entirely below the pressure melting point, so

the glacier is considered frozen to the bedrock, enabling little to no basal flow (Lorrain &

Fitzsimons, 2014). As a result of no basal flow (and consequently no subglacial runoff)

sediments cannot undergo as much weathering and cannot be entrained in suspension as

meltwaters do not percolate to the frozen subglacial bed. However, this paradigm has recently

been challenged. Atkins et al. (2002), Davies et al. (2009) and Waller (2001) have described

processes of debris entrainment and deposition at margins of cold-based glaciers. The

authors’ work also indicate that bedrock erosion in cold-ice glaciers dominantly occurs

through fracture and abrasion. The production of debris in cold-ice glacier margins are a lot

coarser than the sediment produced in temperate glacial environments, with sand being the

dominant product (Hambrey & Fitzsimons, 2010). However, this may be due to a factor

related with global warming, in which cold-based glaciers that were formally present in

exceptionally cold environments, are now exhibiting polythermal glacial characteristics on

their margins as temperatures increase (Willis, 2008).

2.1.3 Polythermal glacier mechanics

The characteristics associated with cold-ice and temperate glaciers are not absolute. Based on

differing air temperatures and geothermal regimes, as well as a warming climate, some

glaciers show characteristics of both cold-ice and temperate glaciers. The name given to these

glaciers is ‘polythermal glaciers’ – ice masses that display a perennial occurrence of

temperate and cold ice (Irvine-Fynn, et al. 2011).

In polythermal glacial environments like Svalbard, with complex thermal structures, sediment

is usually transported by englacial meltwater channels rather than subglacial flows (Hambrey

and Glasser, 2012).

2.1.3.1 Englacial Drainage

The cold temperatures in polythermal non-temperate environments result in low subglacial

flows. However, due to the complex thermal regime of a polythermal glacier, discrete

englacial drainage features occur (Holtermann, 2007). Austre Brøggerbreen, a cold-based


16 | P a g e

glacier with a crevasse-free surface in the Norwegian High Arctic, Svalbard, shows the

existence of englacial drainage networks in cold ice zones (fig. 4) – contrary to previously

held notions regarding drainage through cold ice (Stuart et al. 2003).

A number of mechanisms have been proposed for the development of englacial drainage

through cold ice (Irvine-Fynn, et al. 2011).

Figure 4 | Schematic showing the mechanisms of englacial drainage route formation in polythermal glaciers. Ice flow is

from left to right and water flow is represented by the grey arrows. Conceptual forces acting on the area are shown by the

smaller black arrows (Irvine-Fynn, et al. 2011).


17 | P a g e

2.1.3.1.1 The development of englacial conduits

In non-temperate glaciers, it is possible to reach relatively high incision rates (up to 0.3m d-1)

of supraglacial streams which can develop into englacial conduits (Gulley et al. 2009a).

Englacial conduits are the primary transport systems of water from supraglacial environments

to subglacial flows which descend vertically through the glacier through holes in the surface,

called ‘moulins’ (Dobhal, 2014). The name ‘conduit’ refers to the pipe-like form of the

travelling water through the englacial system, however, other terms have been used to define

this process, namely “cut and closure” channels (Gulley et al. 2009a) or “vadose” channels –

referring to the channels dominated by vertical incision to deeper base levels in the glacier

(Hooke and Pohjola, 1994).

2.1.3.1.2 Crevasse-base incision and Hydrofracturing

An alternative formation of englacial conduits, from deep initial descents from the surface of

the glacier, is through crevassing or fracturing, processes more common in temperate glaciers

(Irvine-Fynn, et al. 2011). Fountain and Walder (1998) proposed that these sub-horizontal

drainage structures could form, simply by the incision of water flows at crevasse bases

pinching off the drainage structure from connection with surface flows (fig. 4b). This

hypothesis has been supported with evidence of deep crevasse drainage structures at a non-

temperate glacier, Storglaciaren by Holmund (1988). Conceptual models of this crevasse-

base incision have shown that lateral propagation of transverse crevasses can lead to further

hydraulic englacial connections (Mavlyduov, 1994; Irvine-Fynn, et al. 2011) which, in turn

can lead to water-filled crevasses or moulins, promoting hydrofractional extensions, aiding

water transport through non-temperate englacial environments up to depths of more than one

kilometre over a few days (Benn et al. 2009; van der Veen, 2007). In the case of cyclical

crevasse filling, hydrofracturing (hydraulically-driven fracturing in the ice) may occur,

spreading laterally (in a zone of minimal tensional resistance [Roberts et al. 2000;

Mavlyudov, 2005]) (Benn, et al. 2009).

Smaller englacial structures, that promote meltwater transport from the top of the glacier to

the base, have been discovered in numerous cave explorations in cold ice sheets and glaciers

(Irvine-Fynn, et al. 2011). However, because these structures are a lot smaller, there is the

potential for the refreezing of the percolating meltwater to impede drainage development

(Irvine-Fynn, et al. 2011). Nevertheless, on sub-seasonal times scales, further cave


18 | P a g e

explorations have reported a large variety of these small channels (both active and inactive)

reconnecting with the larger drainage structures (Irvine-Fynn et al. 2006).

2.1.3.2 Subglacial drainage

The presence of the cold-temperate ice transition zone (the transition within the glacier in

which warm [temperate] and cold-ice characteristics meet) (also known as the “thermal

dam”) has a great influence on ice dynamics and glacier hydrology by regulating down-flow

of glacial meltwater (Rippin, in preparation). Evidence of turbid, highly mineralized water at

the base of non-temperate glaciers, suggests that previously held theories relating to the strict

absence of subglacial flow in cold-base glaciers, are to be reassessed. Presence of hypersaline

mineralised waters at the ice-rock interface can provide lubrication to the base of the glacier,

promoting basal flow in polythermal glaciers (Irvine-Fynn, et al. 2011).

Englacial drainage into the basal layers of the glacier are one source of subglacial drainage

and basal and frictional heating in temperate ice areas may provide another (Aschwanden and

Blatter, 2005). Additionally, variations in season length (summer) and supraglacial water

storage will also have an influence on the development and propagation of subglacial

drainage (Irvine-Fynn, et al. 2011). Observations of polythermal glaciers in Svalbard, have

shown that subglacial drainage tends to correspond with drainage pathways of interstitial

water from the temperate ice zone. Gulley et al. (2009) argue that vadose channels have the

potential to form subglacial pathways in both temperate and cold ice zones, whilst still

remaining directly linked to supraglacial and englacial drainage systems. However, in areas

where significant portions of the base of the glacier are frozen to the bed, these

interconnected flow paths are unlikely to be connected to other regions of the subglacial

environment (Gulley et al. (2009; Irvine-Fynn, et al. 2011). Regardless, theories proposed on

the mechanisms of polythermal subglacial drainage still maintain doubts and uncertainty

(Irvine-Fynn, et al. 2011). Subglacial flow path form assumes water to be in constant motion

(as theorised for temperate glaciers), however, polythermal subglacial outflow is seasonal.

Therefore, theories pertaining to the dynamics of subglacial flow in temperate ice cannot be

wholly applied to polythermal or cold-ice glacier beds, especially considering polythermal

glaciers have the capacity to withhold meltwater storage for long periods of time before it is

released as glacial runoff (Wadham, et al. 2001).


19 | P a g e

2.1.3.2.1 Seasonal variation in subglacial outflow

Water stored within the glacier can continue to increase until water pressure exceeds some

sort of threshold, and a drainage system develops as a result of a rupture (Bingham et al.

2006; Wadham et al. 2001) in the form of artesian discharges or upwellings (Hodson et al.

2005a). However, this results in a significant lag time relative to the onset of the melt season.

The lag time is dictated by the mechanics of the obstructing body constricting outflow

release, which in turn, therefore, results in temporal and spatial distributions in glacial

outflow between different polythermal glaciers (Hodson et al. 2005a; Irvine-Fynn, et al.

2011).

A build-up of water storage at depth can result in high water pressures, leading to features

such as; ice thrust faults, folding, foliation and other features, to be created from weaknesses

in the glacial ice (deeper glacial hydrofracturing) (Glasser, et al. 2003; Skidmore and Sharp,

1999) (fig. 5) . Cases in which water pressures are so high, hydrofracturing may occur higher

up in the glacier, away from the subglacial zone and into the englacial zone, even forcing

meltwaters back into the supraglacial zone (Irvine-Fynn, et al. 2011).

Figure 5 | Potential outflow routes enabling water to pass from the temperate ice zone interior to breach the cold-ice margin

in polythermal glaciers (Irvine-Fynn, et al. 2011).


20 | P a g e

Other examples of subglacial drainage (seasonal outflow) occurs in the form of channel

openings created by two proposed mechanisms; englacial routing and hydraulic jacking

(Rippin et al. 2003). Englacial routing is the process in which vadose drainage pathways are

reopened in cold ice zones, whereas hydraulic jacking occurs when meltwater volumes

exceed the drainage system capacity, leading to ice-bed instability and even failure (Murray

and Clarke, 1995; Irvine-Fynn, et al. 2011). Both these processes can lead to meltwater

pulses that momentarily increase water pressures, promoting subglacial drainage velocities.

These also depend on the effectiveness of hydraulic jacking and the rate of meltwater fluxes

within and outside of the glacier (Röthlisberger and Lang, 1987). However, high water

pressures can lead to a brief period of instability, which is usually followed by a pressure

drop (stabilisation) as the outflow becomes defined through a cold margin (Rippin et al.

2005; Irvine-Fynn, et al. 2011). Overall, the mechanisms associated with hydraulic jacking

are complex and there is little data available to detail the full capabilities of hydrofractures in

promoting subglacial flow in polythermal glaciers (Mavlyudov, 2005).

During winter periods, it is assumed that hydrological outlets are frozen shut or unused (as a

result of alternate slow meltwater pathways) and can lead to potential water storage within

the glacier in macrovoids (such as moulins) or microvoids (such as foliations) and interstitial

spaces up to 100 m3 or more (Schroeder, 1998; Irvine-Fynn, et al. 2011). Observations of a

mapped englacial flowpath at Austre Brøggerbreen in 1998 and 2000, showed a water

volume of ∼8 × 103 m3 retained in a single englacial channel (Irvine-Fynn, et al. 2011).

2.1.3.2.2 Annual water storage and release

Meltwater storage within the glacier may dictate whether there is sufficient energy (melt

volume) required to establish a drainage system, however, meltwater storage varies between

the seasons as well as from year to year.

In Svalbard, the majority of snowmelt occurs within a fortnight (Bruland, et al. 2001) and up

to 70% of seasonal runoff is a result of heat (incident radiation) (Hodson, et al. 2005a; Willis,

et al. 2002; Irvine-Fynn, et al. 2011), of which, < 40% of the summer meltwater volume may

be accounted for (Hodson et al. 2005a). Chemical and terrain analyses have suggested that

only a small proportion (10% - 36%) of supraglacial waters become englacial (Hodson, et al.

2005a). However, studies in Svalbard (particularly at Erikbreen) during 1990, have shown


21 | P a g e

that total summer discharges were estimated to be 10% greater than ablation discharge

volumes, but this exhibits annual variability (Vatne, et al. 1992). Other studies by Hodson, et

al. (2005a), at Midtre Lovénbreen, show that specific storage ranges annually, from - 0.39m

to + 0.68m, compared to specific runoff values (+ 1.1m to + 1.5m) (Irvine-Fynn, et al. 2011).

Irvine-Fynn, (2008) suggested these inter-annual variations in meltwater storage are a result

of antecedent structures that act as water storage locations, thus impacting on the spatial and

temporal variations of seasonal outflows (Bingham, et al. 2006; Hodson et al. 2005a).

Sediments are also built up and retained in these large meltwater stores, so that when the melt

season commences, the variations in total subglacial runoff from year to year may differ

greatly as a result of these large water and sediment stores.

2.2 Glacier Hydrochemistry

As glacial meltwaters interact with unlithified sediments and bedrock, they promote

weathering (both physical and chemical) which results in relatively high concentrations of

dissolved ions in the water. Additionally, solutes derived from interaction with the

atmosphere in supraglacial environments, may also alter meltwater hydrochemistry (Benn

and Evans, 2014). Some of the most common dissolved chemical species (including; anions

and cations, gases and protons) found in meltwaters include; calcium (Ca2+), potassium (K+),

magnesium (Mg2+), sodium (Na+), bicarbonate (HCO-), sulphate (SO42-), chlorine (Cl-) and

nitrate (NO3-), hydrogen ions (H+), oxygen (O2) nitrogen (N2) and carbon dioxide (CO2)

(Benn and Evans, 2014).

Analysis of the composition of meltwater systems provides an insight into chemical processes

occurring within the glacier. However, the solute content in water varies greatly in time and

space (Vanderberg and VanLooy, 2016) and has an inverse correlation with discharge, thus

indicating different hydrochemical compositions of quickflow and delayed flow that exits in

the glacier (Benn and Evans, 2014). Rapid flow velocities reflect efficient glacial conduits

with low solute concentrations, whereas slow flow (often stored within the glacier during

periods outside of the melt season) is solute-rich and has been transported through the less

efficient englacial and subglacial drainage routes (Benn and Evans, 2014). These variations in

glacial output flow rate (and therefore solute concentration variations) can occur both on

short (dilute quickflow dominating proglacial afternoon discharge) and long timescales


22 | P a g e

(seasonal variations). Studies by Sharp, et al. (1995) at Haut Glacier d’Arolla, found that

solute concentrations in glacial runoff were three to seven times higher in winter than in

summer (despite total solute flux remaining low in the winter).

2.3 Glacial sediment erosion

Glaciers are known for producing a large range of sediment debris sizes, ranging from large

boulders to fine-grained silicates (Hallet et al. 1996).

Sediment erosion is possible as a result of glacial movement, known as “sliding” (facilitating

physical erosion processes); and glacial meltwater production (facilitating chemical erosional

processes) (Butcher, et al. 1992; Bogen and Bønsnes, 2003).

2.3.1 Physical erosion

Physical weathering is one of the most dominant forms of erosion in glacial catchments

(Anderson, 2005). The rate of physical erosion is related to the basal thermal regime of the

ice (Sugden, 1978; Butcher et al. 1992; Jacobson et al. 2000), of which; surface temperature,

ice thickness (pressure melting) and the rate of ice deformation (frictional heating) are the

most important factors.

Sugden (1978) identified five main erosional zones. Under the cold-ice base, the glacier is

frozen (“anchored”) to the bedrock, resulting in reduced rates of shear (fig. 6). Surrounding

the basal zone, there are intermittent zones of freezing and melting in which various

processes drive the physical erosion in these zones (Butcher et al. 1992).


23 | P a g e

Figure 6 | Idealised model of the relationship between types of glacial erosion and the basal thermal regime of ice (Singh, et

al. 2011).

There are three main physical weathering1 processes; abrasion, plucking and fracturing

(Jacobson et al. 2000). Abrasion occurs when larger rocks and clasts, embedded into the base

of the glacier, moves with the basal ice, scraping and scouring the bedrock beneath it.

Abrasion can lead to a wide variety of features, from striations to rock drumlins (Singh et al.

2011). Plucking is another form of physical weathering in which the base of the glacier

undergoes melting and refreezing (as a result of differing pressures when encountering a

resistance from an obstructing particle or rock) and ends up ‘plucking’ the rock fragment

from the rock bed (which had been liberated from rock fractures caused by the weight of the

glacier). Plucking and abrasion can also lead to features such as cirques and roches

moutoneés (Singh et al. 2011).

The controls on physical glacial weathering and erosion rates include; basal thermal

dynamics, basal ice-sliding velocity, ice thickness and meltwater availability and pressure

(Singh et al. 2011).

In polythermal glaciers bases and predominantly temperate bases (usually under larger

glaciers), ‘sliding’ at the ice-rock interface physically weathers rock and sediment. The

1 In this paper, weathering refers to the physical or chemical break up of earthen components, specifically rock,

whereas erosion refers to the removal of those broken up or liberated rock fragments from the vicinity, i.e. the

transport of removal of rock debris. Summarily, weathering breaks up and liberates rock pieces, whereas erosion

transports those pieces.


24 | P a g e

velocity of this sliding can also have significant effects on the rate of erosion. The length of

striations caused by rock debris abrasion can indicate the basal-ice sliding velocity.

Velocity can play an important role in the entrainment of particles into the base of the glacier,

as well as the pressure exerted onto the rock bed. With regards to plucking, the greater the

velocity, the more likely high stress contacts between the ice and the clasts form, increasing

the rate of bedrock fracture. Areas of high sliding velocity have been shown to correlate

strongly with large-scale erosion patterns (Singh et al. 2011).

Where ice thickness is greatest, pressure increases, promoting melting at the ice-rock

interface. Abrasion also increases significantly when ice thickness increases, however, under

too much pressure, basal sediment is deposited rather than entrained, so ice thickness has an

ideal range for abrasion rates (Singh et al. 2011).

The availability of meltwaters also play a crucial role in basal ice sliding velocities, as well as

physical and chemical weathering. Freeze-thaw action (water seeping into fractures and

weaknesses in the rock and then freezing, expanding the fracture and increasing the weakness

or susceptibility of the rock to further erosion) and meltwater pressure are important for

moderating weathering rates. Meltwater pressure reduces abrasion effective pressures and the

variability of meltwater pressures over shorter time periods, generating transient stresses,

enhancing rock failure and facilitating ‘plucking’ (Singh et al. 2011).

2.3.2 Chemical weathering and erosion

As rocks are physically weathered from the bedrock as the glacier moves, rock debris is

broken down further as it comes into contract with other hard surfaces. The rock is ground

down to a fine-grained, silt-like sediment known as “glacial rock flour”. As a result of the

production of these fine-grained particulates, sulphides, carbonates, ions and other

geochemically reactive components, are liberated from the silicate mineral matrixes in the

rock (Tranter, et al. 2013). Chemical weathering can occur under these conditions, in which

glacial meltwaters come into contact with reactive rock faces (Hodson, et al. 2002; Anderson,

2005).

The rate of chemical weathering (and whether it occurs or not) in subglacial environments, is

a factor of the availability of meltwaters (in most cases) which transport reactants (protons),


25 | P a g e

such as oxygen (O2) and carbon dioxide (CO2) to the site of chemical weathering (most

commonly subglacial and supraglacial environments) (Butcher, et al. 1992). Rates of

chemical weathering and erosion in glacial environments tend to be lower than the physical

erosion rates compared to the global average. Low temperatures and the lack of availability

of acids or bases, results in low rates of chemical erosion, particularly silica flux. However,

calcium ion (Ca2+) and potassium ion (K+) concentrations tend to be higher when carbonates

and micas are readily weathered (Anderson, 2005; Chutcharavan and Aciego, 2014). Tranter,

et al. (2004) mentions, however, that subglacial environments, particularly those with cold-

base characteristics, exhibit anoxic environments as a result of limited hydrological access.

As a result, there is limited access to oxygen as a chemical weathering reactant (stimulating

redox reactions). However, there are numerous ways in which oxygen and carbon dioxide can

enter the subglacial extreme environment.

Firstly, atmospheric gases can dissolve into supraglacial meltwaters and migrate through the

glacier through englacial linking channels, eventually reaching the subglacial environment

(so long as the meltwater transport medium remains aerated and turbulent). High partial

pressures of carbon dioxide are also encouraged in low temperatures (Benn and Evans, 2010).

Oxygen and carbon dioxide can also enter the subglacial environment through the melting of

ice bubbles in the reglaciated ice, however, this source is limited (Benn and Evans, 2010).

Finally, organic carbon (an important component of chemical weathering and erosion and

nutrient production) can enter the subglacial system in a similar way to oxygen and carbon

(washed down from the glacier surface). Alternatively, it can be introduced from beneath the

glacier, either from residual soils and plant debris, or from organic-rich rock and sediments,

such as organic-rich shales (Grasby, et al. 2003; Wadham, et al. 2004).

However, in small polythermal glaciers, meltwater access to basal ice can be limited

(spatially and temporally) but nutrient fluxes and ion concentrations in meltwaters and

suspended sediment can be surprisingly high. Therefore, the introduction of microbial

counterparts, facilitating chemical weathering from redox reactions at the base of the glacier

is an important concept to consider (Tranter, et al, 2013).


26 | P a g e

2.3.3 Microbial mediation of subglacial reactions

Growing acceptance and supporting evidence of theories associated with the microbial

mediation of reactions that occur within a glacier, are increasingly emerging (Porazinska, et

al. 2004). Evidence suggests that the two main microbially-mediated glacial ecosystems

occur in supraglacial and subglacial systems (Hodson, et al. 2008). The supraglacial system

hosts a diverse consortium of microbes within cryoconite holes (Sharp, et al. 1999; Hodson,

et al. 2008), whereas microbes in the subglacial environment are dominated by

aerobic/anaerobic bacteria, most likely to be viruses (Hodson, et al. 2008). Whilst studies

show some metabolic activity occurring within the englacial system, it is not substantial

enough to impact significantly on nutrient dynamics at the glacier scale (Hodson, et al. 2008).

In subglacial environments, water abundance (ice pressure melt) acts as a liquid medium for

nutrient supply from gases and crushed rock debris minerals (fig. 7), provided that; flow,

turbulence, erosion, turbidity and thermodynamic conditions do not compromise subglacial

niche stability (Hodson, et al. 2008).

Figure 7 | Conceptual model of the relationship between the hydraulic conditions at the glacier bed, the biogeochemical

transfers that take place, and the broad types of bacterial activity. In the channel marginal zone (CMZ) regular (diurnally

fluctuating) exchanges take place between pore waters in the till and the channel water otherwise in transit. “OM” is short

for organic matter (Hodson, et al. 2008).


27 | P a g e

2.3.4 Climate change and future implications

As an aside, as climate change continues and global temperatures in the High-Arctic continue

to rise, it is possible to assume that the processes that facilitate glacial erosion (with the

exception of ice thickness) will lead to a future increase in the erosion rates of sediment in

polythermal environments (Ziaja, 2001; Hagen, et al. 2003). As temperatures become milder

and the summer season lengthens, glaciers bases will adopt temperate characteristics as

opposed to cold-ice, resulting in increased meltwaters and therefore, increased erosion,

resulting in increased material supply to fjords and coastal environments (Elverhøi, et al.

1995; Koppes and Hallet, 2002). Syvitski and Andrews (1994) and Syvitski (2002) predict

that a further rise in sediment flux in the Polar regions is a likely consequence over the next

two centuries. This could have implications on erosion dynamics, sediment flux and marine

(fjord) ecosystems.

2.4 Sediment transport

Sediments entrained by glaciers are deposited, when the forces keeping the sediment or rock

debris adhered to the glacier’s basal surface are weaker than the effect of gravity and friction

on the bedrock. Deposited sediments then either, remain where they are, or are entrained in

glacial meltwaters and transported to downstream environments, undergoing further physical

erosional processes in fluvial transit.

Glacial meltwaters transport sediment in three main ways; as dissolved solutes, as larger

bedload components or as suspended sediment (Chutcharavan and Aciego, 2014). The largest

size fraction (bedload) transports larger sediment debris downstream via saltation or traction

and based on bedload characteristics, is usually deposited first. Dissolved load, on the other

hand, forms an aqueous solution in the water, and is not deposited. Suspended sediment flux

is the finest-grained portion of sediment transport that remains in suspension in the water

column (before gravitational forces and settling velocities are greater than the forces acting

on the particles to keep them in suspension). Of the three types of sediment transport,

dissolved flux is the smallest (only 1 Gigatonne per year), bedload sediment the second

greatest (1.6-10 Gigatonnes per year) and suspended sediment has the greatest flux (15-20

Gigatonnes per year) (Jones et al. 2012).


28 | P a g e

In the case of Svalbard, annual thaw (commencing in early June [Hodgkins, et al. 1997])

results in the production of meltwater. However, as a result of englacial meltwater storage,

there is a lag between when air temperatures are consistently above zero and when meltwater

runoff emerges (Repp, 1988; Hodgkins, 2001; Hodson et al. 2005b). Results from numerous

studies indicate that runoff usually occurs between July and August (Repp, 1988; Hodgkins et

al. 1997; Hodson et al. 1998; Hodgkins, 2001; Hodgkins et al. 2009) but the location of

runoff can vary. As a result of impermeable cold-ice surfaces in polythermal glaciers,

significant proportions of the meltwater is redirected to glacial margins and the proglacial

zone via ice-marginal channels (Hodgkins, 1997; Hodgkins, et al. 2009). It is these relatively

large fluxes of channelled glacial meltwater that are able to entrain sediment, that has been

weathered by the glacier, and fluvially transport it, as suspended sediment, to downstream

environments.

2.4.1 Suspended sediment flux

The suspended sediment flux for temperate and cold-based glaciers, similar to sediment

production and erosion rates, is dependent upon individual glacial catchment characteristics.

Temperate glaciers are renowned amongst the literature, for contributing significant

quantities of suspended sediment flux to downstream environments (Geilhausen, et al. 2009;

O’Farrell, et al. 2009). In the Himalayas alone, annual runoffs of 1.19km3 carry a total

suspended sediment load of 1.8 gigatonnes (Meybeck, 1976), making up approximately 70-

85% of the total annual sediment in the river flow (Kumar et al. 2002).

Studies in Norway have shown concentrations of sediment carried in glacial meltwaters

undergoing large temporal fluctuations as a result of erosion rates and sediment delivery in

each glacial catchment (Bogen and Bønsnes, 2003) (table. 1). Monitoring experiments of

suspended sediment fluxes in the Finsterwalderbreen catchment, in Svalbard, by Hodgkins, et

al. (2003) have shown that the distal sediment fluxes correspond to total catchment

denudation rates (2700 ± 710 t km-2 year-1 [1990] and 1800 ± 350 t km-2 year-1 [2000]), in

which the proglacial area serves as both a source and sink for sediment during different

periods of the melt season. In 1999, results showed aggradation of sediment storage (mean

net flux from the proglacial area was – 690 ± 230 t km-2 year-1), whereas the following year,

there was denudation of sediment (+ 3800 ± 1700 t km-2 year-1). During years in which

sediment supply is exhausted, net sediment storage occurs, and during years in which supply


29 | P a g e

exhaustion does not occur, net release of sediment occurs. Hodgkins, et al. (2003) suggested

that the pattern of sediment storage is driven by the runoff regime. Whilst it will require more

results and long-term monitoring to determine further trends in sediment flux variability, it is

important to note that suspended sediment flux in glacial catchments can be highly variable,

both spatially and temporally.

Table 1 | Suspended sediment transport in three High Arctic rivers in Svalbard (Bogen and Bønsnes (2003).

In sediment-plentiful braided river channels, such as Adventdalen in Svalbard, that lead to the

ocean or fjords (Adventfjorden), meltwaters carve channels in the sediment and migrate

along them as they transport the suspended sediment towards the coastal areas. However,

changes in the distribution of sediment in the fjords, similar to the glacial valley, will be a

result of meltwater discharge and velocity, as well as suspended sediment content. The

meltwater velocity in Adventdalen is different to the surrounding glacial valleys, such as

Endalen, and the volume of suspended sediment will be different (as Adventdalen contains

suspended sediment from the whole glacial catchment, draining many other valleys such as;

Malardalen, Helvetiadalen, Todalen, Foxdalen and many others).

Once suspended sediment has been transported through the glacial valley and entered glacial

fjords, it is deposited in the sea. The deposition of suspended sediment particles is a function

of; increasing salinity, decreasing velocity and the flocculation of fine particles

(Zajączkowski, 2008).


30 | P a g e

2.4.2 Nutrient transport and suspended sediments in glacial meltwaters

The ground-up fine-grained sediment (‘rock flour’), suspended in meltwaters, draining glacial

valleys, contain significant quantities of carbon (Bhatia, et al. 2013; Lawson, et al. 2013) and

nutrients such as; nitrogen (Hodson, et al. 2008) and phosphorus (Follmi, et al. 2009;

Hodson, 2007) and other important components, namely; iron (Hawkings, et al. 2014) and

silicon (Hawkings, et al. 2015) adhered to the sediment particle surfaces (Hodson, et al.

2004).

As the suspended sediment is transported to fjords and coastal margins, nutrients do so too,

however, the nutrient flux and chemical composition emerging from glacial margins is yet to

be fully understood (Crocket, et al. 2012).

Suspended sediment flux is the greatest source of sediment to the ocean and is an important

contribution to ocean biogeochemistry (Chutcharavan and Aciego, 2014). However, the form

in which nutrients are present in the suspended sediment flux, and therefore, the availability

of nutrients and minerals to downstream recipients, is more crucial than the total fluxes.

Sediments with high surface areas, such as glacially produced ‘rock flour’, are ideal for

nutrient acquisition from organisms that rely on it for survival (Chutcharavan and Aciego,

2014).

2.4.3 The role of suspended sediment for global element fluxes

The quantities of annual sediment flux to the oceans does not necessarily denote an impact on

the oceanic biosphere unless nutrients adsorbed to the sediment are bioavailable for

organisms, such as phytoplankton.

Phytoplankton are oceanic photosynthetic microalgae that form the foundations of oceanic

food webs. Phytoplankton utilise inorganic nutrients (such as phosphates, nitrates and sulphur

[and in lesser quantities; iron, manganese and zinc (Diersing, 2009)]) to photosynthetically

produce biomass in the form of; proteins, fats and carbohydrates) (NOAA, 2013). When all

nutrients are in sufficient supply, the phytoplankton can increase in number drastically, in the

surface waters of the ocean, resulting in phytoplankton blooms. Temporal blooms can be

beneficial for the marine ecosystem by providing filter-feeders, sponges and micro-


31 | P a g e

crustaceans sufficient food as they graze on the phytoplankton, which in turn, provide food

for other species higher up in the food web. It is important to note, however, that not all

phytoplankton blooms are beneficial, but in the case of additional nutrient output from

glaciers to oceans, the additional nutrient flux may not be as substantial enough to cause

significant, long-term bloom events. It is usually anthropogenically-related sources that may

cause red tides and other toxic or harmful blooms (Diersing, 2009; NOAA, 2013). Whilst

phytoplankton biomass production, and therefore, oceanic food web productivity, is governed

by the availability of nutrients, the three main components that plankton require for growth

are; carbon, nitrogen and phosphorus, of which, nitrogen and phosphorus are more limited

(sparse) in the natural environment compared to carbon. Nitrogen is an important nutrient and

crucial for photosynthesis. It is used when synthesising proteins and chlorophyll, a pigment

necessary for photosynthesis.

However, despite nutrient sediment fluxes, if phytoplankton are unable to access sufficient

nutrients, biomass and biodiversity does not increase. Therefore, the bioavailability of

nutrients is important (based on the forms of phosphorus and iron) as well as grain reactivity.

The dissolved fraction of components carried by glacial meltwaters will have some sort of

direct effect on water chemistry, but for suspended sediment particles, it may require

additional reactions (Chutcharavan and Aciego, 2014). As suspended sediments react with

seawater, they partially dissolve, which can sometimes result in the re-precipitation of

secondary mineral phases (Jones, et al. 2012).

Numerous factors affect grain reactivity, namely; mineralogical composition, temperature

and grain geometry. Quartz grains are far less soluble that calcite grains, so calcite grains will

dissolve more readily in water (under most normal circumstances), however, both these

minerals will be much less reactive than platy minerals such as micas (Chutcharavan and

Aciego, 2014). Weathering rates also tend to increase with temperature, so particles will be

more ‘ground up’ and therefore have a higher surface area, if air temperatures are higher,

facilitating nutrient liberation and bioavailability in downstream ecosystems.


32 | P a g e

2.4.4 Inorganic nutrients and minerals (phosphorus and iron)

In previous studies, some of the most important sources of phosphorus to the oceans came

from; volcanoes (Yamagata, et al. 1991; Resing, 1997), the atmosphere (Graham and Duce;

1979, 1981, 1982; Migon and Sandroni, 1999), and rivers (Howarth, et al. 1995). However,

recent studies (Hawkings, et al. 2016) have suggested that glaciers and ice sheets

(particularly the Greenland ice sheet) contribute significant phosphorus fluxes to the Polar

oceans.

Phosphorus is an essential nutrient for energy transport and growth in living organisms.

Along with carbon and nitrogen, it makes up the foundations of oceanic biomass in

proportions known as the Redfield Ratio (C106N16P) (Redfield, 1963). However, little is

known about the role phosphorus plays in the production and distribution of phytoplankton in

global oceans (Benitez-Nelson, 2000). One of the reasons for this, states that phosphorus

limits biomass production only over thousands of years. Over time, phytoplankton gain

nitrogen via nitrogen fixation (Tyrell, 1999), which means that as the ratio of nitrogen to

phosphorus (N:P) in the oceans decreases, the presence of nitrogen-fixing organisms will

increase. However, considering long residence times of phosphorus in the oceans, it is often

regarded as a limiting nutrient over long time scales (Karl, et al. 1997; Tyrell, 1999).

Nixon (1993) pointed out that variability in nutrient flux ratios can have catastrophic effects

on marine biomass production and therefore, marine ecosystems. Changing nutrient input

ratios can lead to reduced species diversity, alter phytoplankton composition and increase

intensity and frequency of dinoflagellate blooms or red tides (Benitez-Nelson, 2000).

It is only very recently that the contribution of phosphorus to the marine environment via

glacial sediment flux and runoff has been fully appreciated. Studies by Hawkings, et al.

(2016) have shown that, whilst Arctic rivers contribute significant phosphorus input (126 Gg

per year), the Greenland ice sheet contributes a total phosphorus input of 408 Gg per year,

which accounts for approximately 15% of total bioavailable phosphorus input to the Arctic

Oceans (Hawkings, et al. 2016).

Despite advances in our knowledge of glacial contributions to nutrient output with regards to

phosphorus, studies by De Baar, et al. (1995) and Hawkings, et al. (2014) have highlighted


33 | P a g e

the importance of iron as a limiting nutrient for plankton productivity and consequent carbon

dioxide drawdown.

The combination of physical and chemical weathering as ice moves over bedrock, produces

micro-chemical weathering environments, oxidising sulphides and forming nano-particulate

iron oxyhydroxides (Tranter, et al. 2013; Raiswell, et al. 2006). The refreezing of these

waters back into glacial ice as the seasons progress, trap basal debris, facilitating glacial

transport of potentially labile iron to different proglacial areas (Tranter, et al. 2013).

Under larger glaciers and ice sheets, the residence times of water differ from those under

smaller glaciers, leading to low oxygen and anoxic conditions, generating iron-rich anoxic

water (particularly found under the Antarctic and Greenland Ice sheets) (eq. 1 [Bottrell and

Tranter, 2002]). Once these iron-rich waters are transported to (iron-limiting) marine

environments, they can act as chemical fertilisers for phytoplankton and other organisms

(Tranter, et al. 2013). Some studies have also shown that iron has the potential to limit the

rate of nitrogen fixation as well as the growth of nitrogen-fixing organisms (Karl, et al.

1997). Hodson, et al. (2003) also noted that the production of ferric oxyhydroxide can

potentially govern the mobility and abundance of dissolved phosphorus as a result of

impacting upon the dissolved composition of glacial meltwaters (eq. 2).

FeS2 + 14Fe3+ + 8H2O 2SO42- + 15Fe2+ + 16H+ (Equation 1)

4FeS2 (s) + 14H2O (l) + 15O2 (g) 4Fe(OH)3 (s) + 8SO42-

(aq) (Equation 2)

Advantageously, as phytoplankton activity increases as a result of increasing nutrient influx,

photosynthesis rates increase, resulting in carbon dioxide drawdown from the atmosphere.

Studies by Hawkings, et al. (2014) collected meltwater samples from the Leverett glacier in

Greenland during summer, 2012 and detected large quantities of ferrihydrite (a bioavailable

form of iron nanoparticulates). Their results provided estimates of 400,000 to 2.5 million

tonnes of bioavailable iron flux to the ocean from Greenland’s glaciers (up to 50% of the

global ocean flux of bioavailable iron), and a further 100,000 tonnes from Antarctic glaciers,

rivalling aeolian iron supplies to the ocean (Hawkings, et al. 2014). Although the interaction

of iron with polar ecosystems is not yet fully understood, it is possible that iron-enriched

algae can take in inorganic carbon (CO2) as well as boosting marine life that feed on


34 | P a g e

plankton. However, an increased flux in iron could also have the potential to deplete the

ocean surface of nutrients such as nitrogen (Hawkings, et al. 2014). Regardless, the budgets

and fluxes of nutrients to polar oceans are a relatively novel discovery, therefore the

dynamics and interactions of nutrients with one another and organisms within the polar

marine environment, is still yet to be fully understood.


35 | P a g e

CHAPTER 3 METHODOLOGY


Introduce the sample site (Endalen glacial valley, Svalbard) and data collection

processes involved in this project

Outline the methodologies used to examine both glacial sediment and meltwaters by

including descriptions of the methods involved in; sediment analysis, ion

chromatography, elemental analysis and phosphorus extraction.

3.1 Site description

Previous research into the nutrient content of glacial sediments and suspended sediment flux,

has involved site-specific localities within the field (Pandey et al. 2002). This research

project aims to be the first to conduct research along the entire length of a non-temperate,

polythermal glacial valley in order to better understand how glacial suspended sediment

transports nutrients downstream.

The research and data collection for this project was carried out between 14th August 2015

and the 9th September 2015, in Endalen, a high-Arctic glacial valley in the Arctic archipelago

of Svalbard (fig. 8 - 12).

Figure 8 | The Endalen glacial valley (outlined by a polygon) and surrounding valleys (Toposvalbard, Norwegian Polar

Institute, 2016).


36 | P a g e

Figure 9 | Satellite images of the study area (outlined by polygon - Endalen) to show seasonal variations in snow cover and

ice extent. A) winter B) summer (Toposvalbard, Norwegian Polar Institute, 2016).

The High Arctic has been defined as the area above 75ᵒN which encompasses ca 200 000km2

or 37% of the earth’s glaciers and ice caps (excluding the Greenland and Antarctic ice sheets)

(Hodgkins, 1997). This project will be focusing on the ca 62 000km2 (Hodgkins, 1997)

Norwegian High-Arctic archipelago of Svalbard, in particular, in the north of Spitsbergen in

the Endalen glacial valley, adjacent to Longyearbyen in Svalbard – a catchment

approximately 28km2 (Hodson et al. 2015) – nearby Lars Hiertafjellet, Gruvefjellet and

Longyeardalen (fig. 10).

Figure 10 | Aerial 3D images (3D Orthophoto Pyramiden) A) Catchments adjacent to and nearby the study area. B)

Southern-facing orientation of Endalen glacial valley to view glaciers; Bogerbreen, Nordre Bayfjellbreen and Larsbreen

(Toposvalbard, Norwegian Polar Institute, 2016).

A B

A

B


37 | P a g e

There are a total of 13 sites used in this project, with 8 sites in the Endalen glacial valley (fig.

11).

Figure 11 | Sample sites in the Endalen glacial valley and additional sample sites around the valley at Longyearbyen (LYB

1-3) and Gruvendalen (G1 and G2) (Toposvalbard, Norwegian Polar Institute, 2016).

Fieldwork sites lined the glacial valley, with site 1 closest to the glacier Bogerbreen in the

upper part of the valley, and the last site (site 9) out in Adventfjorden, near the sediment-rich

braided river systems; Dammyra and Adventdalen. Glacial meltwater, active layer thaw, rain

and snowmelt are transported to Isdammen, an artificial lake that provides a winter water

supply to the local residents of Longyearbyen.

Sites coded ‘G1’ and ‘G2’ are from the stream draining Gruvedalen, a valley adjacent to

Endalen but with no glacier at the head of the valley. The three sites starting with codes

‘LYB’ are located in Longyearbyen, further northwest of Gruvendalen and Endalen, at the

very base of the Longyeardalen glacial valley, which drains two glaciers; Larsbreen and

Longyearbreen.

3.1.1 Bogerbreen thermal regime

Bogerbreen, a 3.3km2 polythermal glacier at the top of the Endalen glacial valley (Neumann,

2006), produces a surprisingly vast amount of meltwater discharge at the end of July

(Hodson, et al. 2016). Evidence of striae in Bogerbreen’s terminal moraines support the

theory that Bogerbreen adopted temperate or warmed-based ice during the Little Ice Age


38 | P a g e

(Hodson, et al. 2016). However, as the glacier has thinned, there is little to no evidence of

subglacial drainage (Macheret and Zhuravley, 1982), suggesting an adoption of a cold-ice

base. The presence of a canyon at the margin of the Little Ice Age moraines, further reduces

water storage in the upper part of the catchment, resulting in any surface waters undergoing

rapid transport to the lower valley floodplain (Hodson, et al. 2016).

3.1.2 Lithology and sediments

The lithology of Endalen is dominated by shales, sandstones and carbonates of the Mijenfjord

and Adventdalen Groups, which have very reactive mineral phases of carbonate and pyrite

(Hodson, et al. 2016). In the lower part of the valley; colluvial and alluvial fans, talus

deposits and solifluction sheets, interact with percolating glacial runoff before entering the

large alluvial sediment fan at the mouth of the valley (Hodson, et al. 2016). The rock

sequences of Endalen (Firkanten, Basilika and Grumantbyen coal seams) were commercially

mined in the past2 (now no longer operational), leaving behind waste rocks now subject to

chemical weathering by surface waters during snowmelt and rain in the summer (Hodson, et

al. 2016).

3.1.3 Geochemical interactions

To date, runoff geochemistry has neglected the iron component but note the mineral

composition in runoff (Rutter, et al. 2011). Iron is present as pyrite, siderite and glauconite in

the sandstones (Svinth, 2013) and shales (Riber, 2009). Minor sources of iron also include

biotite and chlorite (Hodson, et al. 2016).

3.1.4 Sediment yields in the Endalen glacial valley

High sediment yields in the valley are a result of geology and geomorphic processes,

resulting in deposition of sediment in the large alluvial fan at the base (or mouth) of the

valley (Bogen and Bønsnes, 2003). The sediment in the alluvial fan is stable, excluding small

valley side debris flows caused by snow-loading (Hodson, et al. 2016).

2 The relict mine is dry so there are no groundwater discharges observable throughout the year.


39 | P a g e

Figure 12 | A) Photographic image of Endalen glacial valley, facing southwest and onto Fardalen in the background. B)

Photograph of Endalen, facing southwest, where the glacial valley mouth opens into Adventdelva (Skoglund, A. Norsk

Polarinstitutt).

3.2 Data collection

A total of 67 sediment samples were taken from the Endalen glacial valley over August and

September 2015 from a total of 13 main sample sites (fig. 11). The data collection duration

lasted over three weeks. There were two main data collection periods (with a break between

the 25th August 2015 and the 30th August 2015). 35 sediment samples were collected during

mid- to late August. The first samples collected on the 14th August 2015 and the last samples

of the first collection phase were collected on the 25th August 2015. A second set of sediment

samples were then collected from Endalen. A total of 32 samples were collected in the second

set, the earliest collected on the 30th August 2015 and the last samples collected at the end of

the collection period on the 9th September 2015 (table 2).

Site Number of samples collected between

14/08/15 – 25/08/15

Number of samples collected between

30/08/15 – 09/09/15

1 7 1

3 5 2

4 7 5

5 5 4

6 5 4

7 1 0

8 5 3

9 2 3

G1 1 0

G2 2 3

LYB1 0 1

LYB2 0 1

LYB3 0 1

Table 2 | Number of samples collected during the two main collection periods in Endalen glacial valley, Svalbard from

numerous site locations.

A B


40 | P a g e

Suspended sediment samples were collected at each site in the valley by rinsing two 500ml

Nalgene sample bottles in stream water and then collecting a sample from below the water

surface. Meltwater samples were taken back to the field lab and stored at 6ᵒC before filtering

(within 24 hours). Samples were filtered through coarse filter papers (1.5μm) and the

supernatant was collected and passed through fine filters (0.45μm).

Meltwater samples were collected by rinsing a syringe three times and then collecting a

sample of stream water. Samples were filtered on site using a 0.2μm syringe filter and stored

at 6ᵒC in Nalgene plastic bottles that had been rinsed six times with deionised water.

All samples were taken back to Cardiff University to be analysed. Samples were transported

to the UK in cool boxes and on arrival at Cardiff University, samples were stored at 4ᵒC in

the dark. Each of the wet sediment filters (coarse and fine) were placed into plastic sealed

bags to prevent moisture loss (a coarse and fine filter in one bag for each site) (fig. 13).

Figure 13 | Sealed (re-sealable) bags containing wet sediment and filters for each sample site

3.3 Sediment analysis (weighing)

Weighing the sediment samples was the first stage of analysis as it allowed me to determine

how much of each sample was present. Knowing the weights and amounts of sediment from

each sample site and at different times in the season will show the distribution of sediment

masses through space and time in the Endalen glacial valley. Furthermore, noting the weights


41 | P a g e

of the sediment for each sample will be crucial when conducting further analyses. The

samples were weighed using an MS analytical balance (± 0.1 mg).

3.3.1 Wet sediment

The first stage of analysis involved determining the wet sediment weight of the coarse and

fine filters (separately) to gauge how much sediment made up each sample. Most sediment

samples collected in the first collection period (14/08/15 – 25/08/15) possessed both a fine

sediment filter and a coarse sediment filter, whereas the majority of samples collected in the

second collection phase (30/08/15 – 09/09/15) were mostly just fine filters with little

sediment. Both these filters were stored in one sealed bag for each sample site. The sealed

bag (containing both filters) was then weighed on the balance and the weight noted.

Afterwards, the bag was opened and the wet sediment filters were individually weighed and

their weights noted down. Tissue paper was laid onto the weighing scales and tared before

placing the wet sediment filter on, to collect excess water seeping from the filter paper. The

tissue was replaced after every sediment filter sample was weighed to prevent cross-

contamination between samples. It is important to note that as soon as the sediment filter

papers were placed individually on the weighing scales, measurements were taken when the

scale reading stabilised, before it began gradually decreasing as water evaporated from the

damp sediment-caked filter paper. Whilst the individual weights of the sediment filter papers

allowed for the most realistic weights of sediment, the weight of all components together (the

bag, sediment and filter papers) minus the weight of the filter papers and the bag, indicated

higher weight values because a small amount of wet sediment remained in the bag that could

not be completely removed and placed onto the sediment filter papers.

3.3.2 Dry sediment

Once all the wet sediments from both collection periods were weighed and their weights

noted, the sediment filters were removed from the bags and labelled. The larger (and more

sediment-packed) coarse filters were placed on pieces of tin foil (large enough to cater for

four), folded [in half and then in half again] and placed in an oven overnight at 40ᵒC (fig. 14).

Coarse filters with lots of sediment were left in the oven for an additional 24 hours to draw

off excess moisture. The fine filters (a third the size of the coarse filters and therefore with


42 | P a g e

less sediment) were air dried. They were placed on a large stretch of tissue paper (still

remaining folded in half) and air dried over several days, covered by another layer of tissue to

prevent airborne contamination of samples.

Figure 14 | Coarse and fine sediment filters placed together on tin foil after 24 hours in the oven.

Once dry, both sediment filters were weighed individually and their weights noted. The

difference in wet sediment weight and dry sediment weight will account for the water present

in the sample that was drawn off either naturally by evaporation (in the case of the fine

filters) or in the oven (in the case for the coarse filters). Knowing the dry weights of the

sediment samples marks the first stage of sediment analysis. The dry sediment remained on

the dry filter papers and stored between tissue paper layers to reduce airborne contamination.

3.4 Ion chromatography (Major ion analysis)

A total of 34 meltwater samples were analysed for major ions (bromide, chloride, fluoride,

nitrate, nitrite, phosphate, sulphate, sodium, potassium, magnesium, calcium) measured using

a Dionex DX-80 ion chromatograph at Cardiff University. Stock standards were purchased

and diluted to the required concentrations (tables 3 and 4). Standards were run at the

beginning of analysis and then again after every 10 samples analysed, followed by Milli-Q

water (blanks). Analysis was conducted by myself and Xiaohong Tang, Cardiff University.


43 | P a g e

Standard solutions (mg/L) Br - Cl - Fl - NO3

- NO2- PO4

3- SO42-

standard original stock 99.84 99.74 19.95 99.90 99.62 199.79 99.67

1/10 dilute 10.14 10.56 2.14 10.07 11.09 20.34 10.34

1/10 then half (1) 4.91 5.16 1.04 4.88 5.24 9.91 5.01

1/10 then half (2) 2.38 2.45 0.49 2.37 2.73 4.86 2.40

1/10 then half (3) 1.18 1.18 0.23 1.19 1.07 2.40 1.18

1/10 then half (4) 0.61 0.50 0.09 0.61 0.22 1.22 0.53

1/10 then half (5) 0.31 0.18 0.03 0.34 0.33 0.58 0.24

1/10 then half (6) 0.20 0.04 0.00 0.20 0.29 0.38 0.12

1/10 then half (7) 0.15 n.a. n.a. 0.16 n.a. 0.26 0.06

1/10 then half (8) 0.11 n.a. n.a. 0.14 n.a. n.a. 0.04

1/10 then half (9) 0.11 n.a. n.a. 0.13 n.a. 0.17 0.02

Table 3 | Standards used in major anion determination (mg L-1)

Standard solutions

(mg/L) Na+ K+ Mg2+ Ca2+

0.5 0.4168 0.5897 0.6141 0.6274

5 4.7692 5.0969 5.0394 5.01

50 51.053 51.6533 51.6609 51.5036

0.05 0.7401 0.2362 0.2391 0.2448

Table 4 | Standards used in major cation determination (mg L-1)

3.5 Elemental analysis

Following the drying of the sediment samples, they were prepared for further analyses. The

elemental analyser produced values of percentage carbon and nitrogen for each sample. The

presence of carbon and nitrogen within the sediment samples will indicate whether the

sediment carries these nutrients to downstream environments. However, in order to determine

that the carbon within the sediment samples is just elemental organic carbon and not carbon

in the form of calcium carbonate (CaCO3) the removal of any traces of calcite is crucial.

3.5.1 Sediment preparation for decalcification

The sediment on the coarse and fine filters for each site were scraped off the filter papers and

mixed together evenly. The mixed sediment was then halved, one half placed in one

centrifuge tube and the other half in another (fig. 15). One half of the sediment sample will be

decalcified and then halved again for elemental and grain size analyses. The other half of the


44 | P a g e

sediment sample will not be decalcified but will be halved again also, one half to be used in

phosphorus extraction and the other to be saved as spare sediment.

Figure 15 | Sediment from coarse and fine fraction combined, mixed with a spatula, halved and then each half brushed into a

small tray to be poured into centrifuge tubes.

The sediment that will undergo decalcification was placed in individual tubes. 2ml 0.5M

hydrochloric acid was added to the sample and then thoroughly shaken in the tube for 30

seconds or until effervescing stopped. The sediment and acid solution were then allowed to

stand for 20 minutes before 10ml of deionised water (DI) was added to each sample. The

sediment samples were then shaken thoroughly and then placed in a centrifuge for 5 minutes

(or more if necessary for larger sediment proportions). The supernatant was pipetted off and

10ml of DI water was added again. The samples were shaken for 20 seconds to thoroughly

mix the sediment and dilute the acid. The pH of the solution was then tested using a pH meter

and the pH recorded (fig. 16). The samples were then centrifuged again and the process

continued, adding 10ml of DI water after the supernatant was extracted. Considering the pH

of the DI water3 added was between 6.4 and 6.6, samples continued to undergo pH checks

until they were within that pH boundary (6.2 – 6.8 [± 0.4])4.

Figure 16 | Step-by-step process of sediment decalcification proceeding from left to right as described in the methodology.

3 The DI water did not have a pH of exactly 7.0 because the carbon dioxide in the air reacted slightly with the DI

solution, changing the pH value ever so slightly with the minimal addition of carbonic acid formation.

4 To account for error in the pH meter of ± 0.2


45 | P a g e

Once the sediment samples had reached a neutral pH (or at least above pH 6.2), they were

then liberated from the centrifuge tubes and placed in small cylindrical trays. They then air

dried over-night (covered by a layer of tissue to prevent airborne contamination) and all

sediments were then thoroughly dried for an additional 18 hours in a 40ᵒC oven.

The sediments, once dried, were brushed out of the individual trays and placed in a pestle and

mortar. The sediment was ground up and placed in a small cylindrical tube. Once all the

samples had been ground up and transferred into smaller tubes, they were then prepared for

elemental analysis. Using a more sensitive weighing apparatus (± 0.1 μg) approximately

25mg of the sediment from each sample site were transferred into 8 x 5 tin capsules and

sealed. Of the 35 samples of sediment that were dried (from the first collection period

because the filter papers during the second collection period did not possess enough

sediment), only 23 had sufficient sediment to be used for additional analysis. Due to budget

constraints, only seven of the sediment samples underwent elemental (CN) analysis in the

Thermo Flash EA 1112 series elemental analyser. Analysis was conducted by myself and

Sandra Nederbragt, Cardiff University.

3.6 Phosphorus extraction

Whilst the nitrogen and carbon content is important to determine nutrient-carrying capacity of

the sediment, conducting phosphorus extraction will enable me to gain an insight into the

amount of phosphorus adsorbed to the sediment, as well as the bioavailability of phosphorus

present in the suspended sediment.

Due to its physical and chemical properties, phosphorus is readily dissolved in the natural

environment, which can pose both benefits and disadvantages to microorganisms that use it.

The more bioavailable the phosphorus is to microorganisms, the greater the potential for

nutrient uptake in downstream ecosystems. After the bioavailable phosphorus (NaOH-P) is

taken from the suspended sediment (either by microorganism uptake or dissolution), a small

amount phosphorus remains, however this is a lot more difficult for microorganisms to

‘access’. Whilst it is not entirely considered ‘readily’ bioavailable, it is also not considered

strictly ‘non-bioavailable’. Microorganisms would need to utilise enzymes in order to access

the remaining phosphorus. Whilst this is possible in a phosphorus-limiting environment, for


46 | P a g e

this particular locality in Svalbard, phosphorus can be accessed elsewhere. Using a sequential

extraction technique, I will be able to determine, not only the amount of phosphorus within a

sediment sample, but also how much of that phosphorus is available for microorganisms to

utilise and therefore what impacts there are on the nutrient status of the ecosystem.

3.6.1 Extraction method

The methodology laid out by Hodson et al. (2004) of phosphorus extraction, is the one that I

will use for this stage of the project, however there are slight amendments to the method. I

will be using chemicals suggested in experiments in phosphorus extraction conducted by

Meis et al. (2012) rather than the solutions used by Hodson et al. (2004).

A 1M solution of ammonium chloride (NH4Cl) was added to the samples first in order to

extract the ‘loosely bound’ phosphorus. The next phase of phosphorus extraction used a 1M

solution of sodium hydroxide (NaOH) in order to extract the Fe and Al oxyhydroxide bound

phosphorus. The final stage of extraction utilised a 0.5M solution of hydrochloric acid (HCl)

to liberate the calcite- and apatite-bound phosphorus.

A total of 12 sediment samples were analysed and prepared for phosphorus extraction that

encompassed the length of the Endalen glacial valley and included one duplicate sample. 0.2g

of sediment were placed in centrifuge tubes. 12ml of a 1M solution of NH4Cl was then added

to the sediment and the solution was shaken for 30 minutes. The samples were then

centrifuged for 12 minutes at 2700 rpm and the supernatant was poured off into labelled

containers (one for each site and for each acid/base used for phosphorus extraction – 12 x 3

containers of supernatant in total). Another 12ml of NH4Cl was added to the sediment and the

samples were shaken for 5 minutes before centrifuged for 12 minutes. The supernatant was

poured off and added to the same containers for each sample. Finally, 12ml of deionised

water was added to the sediment samples and they were shaken for 1 hour and then

centrifuged for 12 minutes. The supernatant was once again poured off. The process was

repeated for NaOH but with a different initial time. 12ml of NaOH was added to the sediment

samples and they were shaken for 16 hours. They were then centrifuged for 12 minutes and

the supernatant was poured off into different containers (for NaOH for each sample location).

Another 12ml of NaOH was added, shaken for 5 minutes, centrifuged and the supernatant


47 | P a g e

collected. Then 12ml of deionised water was added, shaken for 1 hour, centrifuged for 12

minutes and the supernatant collected. The process was repeated once more for HCl with the

same timings as NaOH.

3.6.2 Colourimetric determination of phosphate

Once the supernatant had been collected for each sample, the standard solutions for the

colorimetric determination of phosphate for the use of the UV/Vis spectrophotometer were

prepared.

A standard stock solution of phosphorus of 100 mg P dm-3 was prepared by adding 0.11g of

KH2PO4 in deionised water and diluting to 250 cm3 in a volumetric flask (stock solution A).

10cm3 of stock solution A was then added to a 250cm3 volumetric flask and filled with

deionised water to create stock solution B. To prepare the standards, the following

components were added (table 5).

Standard

solution

0.20 P dm-3 0.40 P dm-3 0.60 P dm-3 0.80 P dm-3 1.0 P dm-3

Quantity of

Stock solution

B added

5 cm3 10 cm3 15 cm3 20 cm3 25 cm3

Table 5 | Standard solution preparation quantities

Standard solutions needed to be prepared in the same proportion as the supernatant

(extractants) samples for each phase of phosphorus extraction (NH4Cl, NaOH and HCl). For

the first set of standard solutions (NH4Cl), 66ml of NH4Cl was added to each of the standard

solutions and deionised water filled the remainder of the 100 cm3 volumetric flasks. The

same standards were made up for the other phases of phosphorus extraction in which 66ml of

NaOH was added to the standard solutions and 66ml of HCl was added to the standard

solutions on each run or phase of extraction analysis.


48 | P a g e

3.6.3 Combined reagent

Extractants were analysed using the molybdenum blue method on a Cary 60 UV-Vis Agilent

Spectrophotometer at 880nm wavelength. Ammonium molybdate tetrahydrate solution was

combined with potassium antimony tartrate, ascorbic acid and sulphuric acid (table 6) to

make the combined reagent.

Compound Solution strength Volume in combined reagent

H2SO4 5M 50ml

Ascorbic acid 1.76g/100ml 30ml

(NH4)6Mo7O24 · 4H2O 10g/250ml 15ml

K2Sb2(C4H2O6)2 · 3 H2O 0.2743g/100ml 5ml

Table 6 | Component quantities required to make up the combined reagent used for UV-Vis spectrophotometry.

The combined reagent is stable for 24 hours. 0.64ml of the combined reagent was added to

clean centrifuge tubes with 4ml of standard solution or extractant. The solution was mixed on

a vortex mixer and was left for 20 minutes to allow the blue colour to develop. The samples’

absorbance was then measured on the spectrophotometer (in which the blanks5 were run first

and zeroed before the standards). The standards’ (0.2 – 1.0 mg P dm-3 [with the same matrix

as the extract solution]) absorbance was recorded and used as a baseline for comparing

absorbance from the extractants (fig. A7, A8 and A9 – see appendix).

5 Blanks were created using 0.64ml of combined reagent and 4ml of deionised water.


49 | P a g e

CHAPTER 4 RESULTS AND DISCUSSION

This chapter:

Presents and analyses the results for each of the key findings and datasets:

- Sediment analysis

- Ion chromatography of meltwaters

- Particulate phosphorus concentration of sediments

- Elemental analysis

Discusses the potential reasons for data trends

Outlines the limitations of the study whilst also presenting recommendations for

further study.

4.1 Sediment analysis

The dried sediment samples were weighed and their average yields calculated. The suspended

sediment flux was then graphically represented for each site in the valley, as well as for each

sample collected over the collection period.

4.1.1 Spatial variation in suspended sediment

Of the dried and reweighed sediment samples, data was plotted to show how the sediment

flux changed spatially (fig. 17 - 20) and temporally (fig. 21 - 23 and table 7) throughout the

Endalen glacial valley.

Figure 17 | Average sediment flux of coarse and fine sediment across the Endalen glacial valley. Average flus was

calculated by taking the total flux of sediment for each grain-size fraction (coarse and fine) and dividing that by the total

number of samples collected (including duplicate samples).


50 | P a g e

Sediment samples at sites 4 and 7 showed the greatest sediment flux for both coarse and fine

sediment fractions (although it is more exaggerated in the coarse fraction). There is also a

marked increase between sites 1 and 3, as well as sites 3 and 4. Site 9, despite being in a

sediment-rich environment in Adventdalen (a braided river system leading toward the ocean,

Adventfjorden), has the least amount of sediment.

Figure 18 | Aerial view of the Endalen glacial valley sample sites with corresponding average sediment flux proportions

visually represented as blue circular polygons. The polygons were created with the aid of GIS (for dimensional and

proportional appropriation) and were cut and transposed to the basemap for sample sites (fig. 11)

It is expected that sediment at site 1 is minimal because it is closest to the glacier. Whilst

meltwaters and sediment are present on the glacier’s outskirts, the conditions there are not as

‘meltwater rich’ as sites further downstream, therefore, not a lot of sediment was captured in

suspension. The average sediment flux at site 3 was more than double that at site 1. Site 3 in

the valley was at the main stream or meltwater flow path, draining the Bogerbreen glacier,

but it also was just after a small adjoining tributary from an even smaller glacier, Nordre

Bayfjelbreen. The addition of sediment flux from this small glacier, in addition to the

distance downstream from the previous site, contribute to increasing the sediment flux


51 | P a g e

spatially. The distance between site 3 and site 4 was the greatest in the valley, allowing

sediment to either be deposited or resuspended with meltwater transport throughout the

proglacial valley. During this distance, more tributaries (fig. 18) join the main proglacial

stream from the valley walls, one of which, drains an even smaller glacier still (unnamed).

This must contribute to an increase in sediment yield. Interestingly, sites 5 and 6, exhibit a

decrease in sediment flux, indicating that either, concentration of suspended sediment in the

proglacial meltwater main stream decreases, or, sediment is deposited (or both). As more

tributaries join the main channel, discharge is expected to increase, but the slope of the valley

begins to level out and channel begins to widen (reducing flow rate) and depositing material.

However, the majority of coarse-grained and fine-grained suspended sediment (at least the

fine-grained) would remain in suspension. However, when looking at figure 17, the fine-

grained fraction also exhibits a decrease in sediment, indicating that meltwater discharge

must have increased to dilute the sediment. Site 7 highlighted the greatest sediment content in

the samples out of all of the sites in the valley. However, it is important to note that,

compared to other sites with multiple samples, only one sample was collected at site 7 (fig.

19). So whilst other sites show average sediment flux over all collection phases, site 7 shows

the only suspended sediment flux taken from the one sample at that site.

Figure 19 | Number of samples, for the coarse fraction and fine fraction, taken at each site.

Whilst the value at site 7 is not considered anomalous, it is to be treated with caution as it is

not as representative of the study site as much as the other sites are (with more samples to

provide an average).


52 | P a g e

Finally, site 9, outside the valley (Endalen) and in the area (Adventdalen) leading towards the

fjord (Adventfjorden), showed a large decrease in sediment flux, most likely due to the

increase in glacial meltwater draining the area, reducing suspended sediment concentration.

Measurements in the adjacent (non-glacial) valley, Gruvendalen, show that suspended

sediment flux is a lot less in smaller, unglaciated valleys. Measurements of suspended

sediment flux in Longyearbyen were non-existent and produced values of 0.00g. However,

samples taken from Longyearbyen were later on in the season (early September), when

glacial runoff was low as ice began to freeze, storing water within the glacier

(Longyearbreen).

Figure 20 uses the data from the sample sites in the Endalen glacial valley (and site 9) and

applies a simple linear regression to denote a trend in spatial suspended sediment yield.

Figure 20 | Average suspended sediment yield for sites 1 – 8 in the Endalen glacial valley and site 9 in Adventfjorden with

simple linear regression analysis applied. Values for y and R2 are displayed in the figure.

Despite the observed variations in sediment amounts throughout the valley spatially, the

overall flux of sediment exiting the valley remains the same. The trend shows a very slight

decrease in average sediment flux as it progresses down the valley. These trends may be

subject to change seasonally or temporally throughout the valley.

4.1.2 Temporal variation in suspended sediment

The suspended sediment average yields were taken for each sampling period. The sampling

periods were divided up into four main categories; early-mid August, mid-August, late

August and early September (fig. 21).


53 | P a g e

Figure 21 | Number of samples collected during each main sampling period for coarse and fine filter fractions.

Similar numbers of samples were collected for each sample period, however, in early

September, no sediment in the coarse filter fraction were collected. This was because, as the

melt seasons progressed, temperatures dropped in early September and meltwater discharge

reduced significantly. With low glacial runoff, as a result of meltwater being retained within

the ice, very little sediment was carried in suspension and so only the fine fraction could be

collected. After the onset of September, there was very little suspended sediment flux

(despite fine filter sample collections), if any (fig. 22)

Figure 22 | Average suspended sediment yields over time (per day). Some days did not have a sampling period, whereas

others did. Data is categorical but the x axis remains as a timescale. Polynomial regression analysis was applied to see the

relationship with the samples over time. Linear regression was skewed heavily by the high flux of sediment on the 17th

August. Equations for y and R2 are presented in the figure. The shaded background colours correspond to each data sampling

period; pink for early-mid August, orange for mid-August, green for late August and blue for early September. Early to mid-

August includes dates ranging from 14th to the 19th. Mid-August accounts for 20th August to the 25th August. Late August

refers to 26th to 30th and early September ranges from 1st to the end of the sampling period, 7th September.


54 | P a g e

The average sediment yield per day, was calculated based on the total sediment yield per

sampling day and the number of samples taken at all sites for each day (fig. 23).

Figure 23 | Number of suspended sediment samples collected throughout the collection period.

Regardless of spatial context, sediment yield was greatest on the 17th August, fluctuated at

the transition between early-mid August and mid-August, and steadily declined towards the

end of the sampling period. This is most likely due to similar reasons as to why there were

fewer coarse samples collected in late August and early September. As the temperature

begins to drop again at the end of the melt season, previously active and running meltwater

channels exiting the glacier, begin to freeze again, reducing meltwater outflow from the

glacier and therefore, reducing stream discharge and flow in the proglacial valley. With a

reduction in meltwater flow, there is a reduction in the erosion rate of sediments in the

glacier, as the presence, availability and pressure of meltwater is crucial for facilitating

physical and chemical weathering within the glacier, as well as transporting sediment down

the valley. As a result, sediment flux decreased as the meltwaters decreased as the season

progressed (table 6).

Table 6 | Average sediment yields for coarse and fine sediment fractions for each sampling period and the standard

deviations of each data set.

Date

Average coarse

sediment flux

(g)

Standard

Deviation

Average fine

sediment flux

(g)

Standard

Deviation

early-mid Aug 0.84 0.435 0.12 0.080

mid Aug 0.33 0.075 0.04 0.010

late Aug 0.06 0.039 0.01 0.001

early Sept 0.00 0.000 0.05 0.082


55 | P a g e

4.1.3 Discussion of suspended sediment flux variability and recommendations for study

improvements

The data shows a variation of sediment yield spatially in the glacial valley, despite a

relatively linear relationship overall. It also shows a gradual decrease in sediment over time.

In order to gain a better insight into suspended sediment flux patterns, monitoring the flux

over numerous years (as opposed to just one melt season) would provide information on the

annual variations of suspended sediment flux from a polythermal glacier. Studies by Bogen

(1996) and Hodgkins, et al (2003) have shown that there can be large variations in the

suspended sediment budget in the proglacial area from one year to the next and

Zajączkowski, et al. 2004) have shown that these sediment yields vary ever more so on

longer, decadal timescales.

In order to better understand spatial variations in suspended sediment flux, monitoring

meltwater discharge and velocities from the glacier and into the proglacial area, through the

valley, would allow me to understand whether there is a significant relationship between

suspended sediment concentration in the water and spatial distribution in the valley. It would

allow me to see how sediment concentrations change with turbidity and discharge of glacial

meltwaters and to see whether that strength of relationship is related to a temporal factor.

When meltwater discharges are high, will that correspond to equally high rates of suspended

sediment flux (namely, on the 17th August 2015).

As suspended sediment content varies with subglacial runoff, it could indicate a transition

towards a fast, efficient subglacial drainage system (Hodson and Ferguson, 1999; Irvine-

Fynn, et al. 2011). However, other studies have shown that continued increases in subglacial

suspended sediment from polythermal glaciers, may be a result of increased water volumes

being delivered to the subglacial environment, primarily controlled by the glacier’s thermal

regime as opposed to the evolution of the subglacial drainage system (Vatne et al. 1992;

Irvine-Fynn, et al. 2011). Furthermore, by increasing the time period of data collection, it

would allow for greater understanding of patterns associated with the lag in glacial meltwater

export from polythermal glaciers. Increased understanding of englacial and subglacial

meltwater storage channels and interlinkages, will reflect temporal variations in sediment

yield measurements by characterising the sediment delivery component. The sediment stored

within the meltwaters or locked in the ice of a polythermal glacier can be stored for long


56 | P a g e

periods before release as suspended sediment in proglacial streams, so long-term monitoring

of meltwater discharge and suspended sediment yields, coupled with polythermal glacial

thermal regime dynamics, will allow for a better understanding of the relationships between

sediment yields and glacial meltwater dynamics.

Additionally, being able to acquire more sample data from other glacial valleys within

Svalbard (with varying polythermal characteristics) will enable determination of potential

patterns identifying links between glacial mass balance, thermal regime and meltwater runoff,

and therefore, consequently, suspended sediment yield (as attempted by Hodson and

Ferguson, 1999). Whilst numerous other studies of polythermal glaciers in High-Arctic

Svalbard conform to the notion that suspended sediment yields are not as high as those from

larger temperate (warm-based) glaciers, studies by Bogen and Bønses, (2003) show that the

polythermal glaciers of Svalbard do plot within the range of temperate mainland glaciers. It

could be predicted that there will be correlations between suspended sediment flux and

glacier dynamics, but it is also important to understand that the nature of the bedrock must

also be considered. Studies by Bogen and Bønses, (2003) show that erosion rates are greatest

in areas where glaciers are underlain by ancient crystalline bedrock.

Finally, grain size analysis of the sediment would have been ideal to determine whether there

are significant correlations between the spatial distribution of sediment within the valley and

grain size. Grain size will have a significant effect on particle settling velocity. It would also

be interesting to see if relationships exist from a temporal perspective – whether suspended

sediment grain sizes differ throughout the melt season.

4.2 Elemental analysis

Sediment samples (post-decalcification) were analysed in a Thermo Flash Elemental

Analyser to determine percentage nitrogen and carbon content within each sediment and their

respective ratios. A total of 7 samples were analysed.


57 | P a g e

4.2.1 Spatial trends in elemental content of suspended sediment

Figure 24 | Percentage carbon (% C) and percentage of nitrogen (% N) in the seven samples taken at different sites along the

valley.

Similar to trends in suspended sediment flux, there was a large increase in carbon and

nitrogen content (although nitrogen to a lesser extent) between sites 1 and 3 (fig. 24). This

suggests that the contribution of suspended sediment flux from the smaller adjacent glacier

(Nordre Bayfjelbreen) contained a greater amount of sediment with higher nitrogen and

carbon content. The slight similarity between the elemental content and suspended sediment

flux (increasing values at sites 3 and 4, decreasing values at sites 5 and 6, and a lower value

still at site 8) highlights a potential relationship between suspended sediment yield and %C

and %N content, however, the patterns are not entirely similar. There are numerous reasons

for this. Firstly, earlier figures of suspended sediment flux utilise averages of far more

sediment samples in comparison to elemental analysis. With more samples run in the

elemental analyser, it would be possible to determine whether the average carbon and

nitrogen content of the sediment reflect similar patterns of concentration with suspended

sediment concentration. The other reason as to why there are differences is because

suspended sediment concentration or flux does not necessarily represent elemental content or


58 | P a g e

availability. The dimensions of the sediment particles themselves will determine carbon and

nitrogen compositions as well as the sources of rock. Carbon-rich rocks, such as organic-rich

shales in the Canadian and European High Arctic, will have a higher carbon content in

sediment particulates compared to other rocks (Grasby, et al. 2003; Wadham, et al. 2004).,

such as granites, which will have a greater silicate content. Additionally, the microbial

mediated component of chemical weathering will also have an effect on the elemental

composition of suspended sediment.

Evidence of nitrification in many glacial environments (Arctic, alpine and Antarctic [Hodson,

2006]), have been identified from the production of NO3- from NH4

+ in the snowpack.

Studies by Wynn (2004) and Wynn et al. (2007) show that for Midtre Lovénbreen in

Svalbard, the NO3- is isotopically enriched as a result of bacterial processes occurring in

subglacial sediments (Hodson, et al. 2008). Whilst it is also possible that mineralisation of

organic nitrogen to NO3- from the bedrock, may also be a distinct possibility as a result of the

shales dominating the geology of the Endalen glacial valley, the biogeochemistry of nitrogen

in glacial meltwaters is a product of at least some microbial activity and is most certainly a

complex process to understand.

Theories surrounding the introduction of carbon to the subglacial environment, are numerous

and vary depending on glacier location. Better known concentrations of total dissolved

organic carbon in meltwaters are said to be between 0 – 10 mg L-1 (Skidmore et al. 2005).

Other theories propose organic carbon has been imported from the in-wash of surface

(supraglacial) sources (Tranter, et al. 2005). Hodson, et al. (2008) state that more research

attention be given to the role of chemoautotrophic and chemolithoautotrophic bacteria in the

subglacial environment and their role in the creation of biomass from organic carbon

substrates.

4.2.2 Temporal variation in elemental content of suspended sediment

Very few samples could be analysed over time, but, of the seven samples analysed,

(approximately) two samples were taken each day (at similar intervals between sampling

days [2-3 days between each sampling day]) with very minimal standard deviation (although

greater in carbon that in nitrogen content) (table 8).


59 | P a g e

Table 7 | Average percentage nitrogen and carbon content in sediments and their standard deviation.

There appears to be little to no variation in percentage nitrogen and carbon content over the

sample period. Differences in elemental composition in suspended sediment appear to

fluctuate spatially, which supports the hypothesis that it is a result of source rock and

microbial activity that result in spatial differences as well as sediment distribution throughout

the proglacial valley.

4.2.3 Carbon:Nitrogen ratios and their implications

Carbon and nitrogen make up two of the three components of the ‘Redfield ratio’, which is

the atomic ratio of carbon to nitrogen to phosphorus found in phytoplankton, which form the

basic foundations of life in oceanic ecosystems. Therefore, understanding the amount of these

elements in relation to one another is important to determine whether there are sufficient

quantities of each component or whether there is less of one in the environment than the

other, acting as a limiting component.

Figure 25 | The percentage of carbon and nitrogen, in relation to one another, in the suspended sediment in the Endalen

glacial valley.

no. of

samples date av. N % av. C %

2 14/08/15 0.10 2.07

1 17/08/15 0.08 1.63

2 19/08/15 0.09 1.36

2 24/08/15 0.12 2.41

st. dev. 0.016 0.404


60 | P a g e

Figure 26 | Spatial variation of ratios of carbon and nitrogen in each site in the Endalen glacial valley.

Figures 25 and 26 highlight the consistency of the relationships between carbon content,

nitrogen content and spatial distribution along the valley. They both show that with the

exception of site 1, the ratios of carbon and nitrogen along the valley remain the same. This

illuminates the concept, for future glacial research in the Endalen valley, that suspended

sediment samples can be taken from any part of the valley (after the tributary draining Nordre

Bayfjelbreen) and will have similar, if not the same elemental composition6.

Another important observation to note in figure 26 is that carbon is not a limiting component

in the valley, meaning that there is sufficient carbon in the sediment to support phytoplankton

growth (if the sediment reaches the fjord and if the carbon is bioavailable for phytoplankton).

The ratio of carbon in the Redfield ratio is 106. When divided by its own atomic mass

(16.01), it gives a value of 8.8. Considering all the values of the C:N ratio are above 8.8 in

figure 26, it shows that carbon is not a limiting reagent. The same can also be said for

nitrogen. The ratio of nitrogen in Redfield stoichiometry (16) is divided by nitrogen’s atomic

mass (14.01) to produce a value of 1.14. Once again, all values are above the C:N ratio

critical value which suggests that nitrogen is also not a limiting component in the glacial

system.

6 Acquiring more samples will increase the reliability of this statement.


61 | P a g e

4.3 Ion chromatography

Meltwater samples from sites in the Endalen valley, as well as in the adjacent, non-glacial

Gruvendalen valley and site 9 in Adventdalen, were analysed. The major ions analysed

included; bromide, fluoride, chloride, phosphate, sulphate, nitrate and nitrite anions, and;

calcium, magnesium, potassium and sodium cations.

Ion concentrations appeared to be greatest on the 22nd August (fig. 27). If total discharge

from Endalen and Gruvendalen were known, it would be possible to determine whether major

ion flux is significantly linked to total discharge.

Figure 27 | Major cation concentrations, over time, for site 4 (with error bars)


62 | P a g e

Figure 28 | Major cation concentrations for numerous sites along the Endalen glacial valley on; A) 17/08/15, B) 19/08/155,

C) 22/08/15 and D) 24/08/15. G2 is the non-glacial valley, Gruvendalen, adjacent to the field work site. Note the differences

in scale (mg/L) for each graph.

Concentrations of the major cations in meltwaters showed that, for most sampling days, ion

concentration increased further down the valley. Calcium ions were in the greatest

abundance, evident of the carbonate lithology that dominates the valley. Magnesium and

sodium displayed similar values and characteristics both spatially and temporally and fluoride

ions, despite being the lowest concentration, still maintained a very slight increase in

concentration through the valley. Site 6 also exhibited a peak in ion concentrations (which

may not appear as evident in graph C because of the large change in scale, but it is still

present), whereas at site 8 at the end of the valley, the trend ceased as cation concentrations

decreased. Additionally, Gruvendalen appeared to have concentrations of cations far greater

than sites in Endalen (fig. 28) despite not having a glacier (fig. 29).

Figure 29 | Gruvendalen runoff source (Toposvalbard, Norwegian Polar Institute, 2016)


63 | P a g e

Studies of reach-scale cation exchange controls in an Antarctic glacial meltwater stream by

Gooseff, et al. (2004a) found that, whilst chloride concentrations remain relatively constant,

sodium ions (Na+) were released into the water column as they travelled downstream, and

potassium ions (K+) were taken up. Hodson, et al. (2002) suggested that Na+ transport is

controlled by reacting ion exchanges. Gooseff, et al. (2004a) noted in their study that

discrepancy in the mass balances of K+ were probably due to ion exchange involving calcium

and magnesium ions (which were not directly measured in the experiment). Their other

theory suggested that the sodium and potassium cations underwent ion exchange and

adsorption reactions to the suspended sediment and streambed sediments (Gooseff, et al.

2004a). A later paper by Gooseff, et al. (2004b) summarised that streams and meltwater flow

control the quantity of solute load on glacial meltwater, and microbes control inorganic

nutrient fluxes (particularly nitrates and nitrites).

Figure 30 | Major anion concentrations for numerous sites along the Endalen glacial valley on; A) 17/08/15, B) 19/08/155,

C) 22/08/15 and D) 24/08/15. G2 is the non-glacial valley, Gruvendalen, adjacent to the field work site. Note the differences

in scale (mg/L) for each graph. Other anions were also measured, but gaps in data were too great to plot for bromide and

phosphate ions and concentrations of sulphate ions were much higher, distorting visual scalar relationships.

Anion concentrations exhibit similar patterns to cation concentrations, however, there are

some differences. Figure 28 showed that cation concentrations at site 6 were higher than at

other sites in the valley, however, the opposite is the case for anions. Similarly, whilst all

sites show a general increase in cations through the valley (as site number increases), nitrite


64 | P a g e

concentrations decrease. Finally, similar to cation concentration, bromide, nitrate, fluoride

and chloride ions increase at the Gruvendalen site, but nitrite anions decrease in concentration

dramatically (fig. 30).

The interactions of ions and solutes in glacial meltwaters are difficult to understand. Waters

draining the surface of the glacier can bring with them, nitrate, sourced from exchanges

between the snow and atmosphere (Dibb, et al. 1998; Beine, et al. 2003). However, further

research is required in order to understand nitrate localisation and reactivity whilst in snow,

as well as when adhered to cations (such as calcium and sodium) in meltwaters (Beine, et al.

2003).

As a result of nitrate and nitrite atmospheric introduction to snow (and eventually glacial

meltwaters), it would be interesting to compare the pH of the meltwaters. Vanderberg and

Vanlooy (2016) suggest that the presence of NOx species will decrease glacial meltwater pH

to approximately 6.0 pH. This could, therefore, have an effect on the solubility and reactivity

of other ions in the glacier hydrological matrix.

Investigations conducted by Koziol, et al. (2014) have shown that concentrations of nitrite

and phosphate are high when superimposed ice melts, forming glacial runoff and when

exposed in the catchment. This could suggest another source of nitrite. However, considering

phosphate levels were almost negligible (all but one IC values were “n.a.”), this source may

not represent the main nitrite source.

Examining the literature has shown that microbially-mediated reactions in subglacial and

supraglacial environments account for significant proportions of ions and solutes present in

glacial runoff. The presence of nitrogen-fixing bacteria (or in the case of Svalbard cryoconite

holes, allochthonous, bio-available nitrogen [Hodson, et al. 2008]), on the surface of the

glacier, produce nitrogen to be used by nitrifying bacteria to convert nitrogen into nitrates and

nitrites, which are then transported through the glacier by englacial conduits and meltwater

flows (Telling, et al. 2011). In subglacial (or even englacial storage) environments, bacteria

may continue to produce nitrates and nitrites which are carried by glacial runoff through the

valley. At site G2, nitrite concentrations decrease and are much lower compared to other sites

in the Endalen valley. This suggests that nitrifying bacteria, present on the glacier, may not be

as abundant in Gruvendalen, however, this is merely a theory.


65 | P a g e

Figure 31 | Spatial and temporal variation in sulphate ion concentration (SO42-).

This trend in ion concentration peaks at Gruvendalen continued for sulphate ions (which

exhibited the highest concentrations of all ions – so much so that it could not be graphed with

other ions to prevent scalar skewing). The high sulphate concentrations in the valley could be

a result of microbial activity relating to interactions with iron species in glacial meltwaters

and consequently, the production of ferric oxyhydroxides.

Benn and Evans, (2014) suggest that when meltwater velocities are low, solute and ion

concentrations are high, however this suggestion mostly applies to meltwaters composing

glacial runoff. Slow flow velocities are indicative of less-efficient englacial and subglacial

drainage routes, allowing meltwaters to remain within the glacier for longer, as water reacts

with the solutes and constituents it contains, developing a solute-rich matrix (Benn and

Evans, 2014). However, this does not necessarily apply to Gruvendalen because there is no

glacier. During winter, however, ice is present, as is snow. The high concentrations of ions

could be a result of interactions between atmospheric gases and melting snow. It could also

be a result of interactions with the underlying rock (despite decreased weathering rates, due

to a lack of glacier).

4.4 Phosphorus analysis

The standard solutions (0.64ml combined reagent and 4ml of standard phosphorus solution

[0.2 mg dm-3, 0.4 mg dm-3, 0.6 mg dm-3, 0.8 mg dm-3 and 1.0 mg dm-3]) were run for

absorbance in the spectrophotometer. Their absorbance readings were then plotted against

their known concentrations to produce a calibration curve (straight line equation) (fig. A7, A8


66 | P a g e

and A9). For ammonium chloride (NH4Cl), the data points fit well to the line, however, the

data points (absorbance) for the other two stages of phosphorus extraction; sodium hydroxide

(NaOH) and hydrochloric acid (HCl) did not line up, despite numerous attempts to eradicate

the issue. Therefore, in order to work with the material available, a linear regression was

applied to data points that best fit the equation of the line (see appendix). The equation of the

line was calculated and solved for ‘x’ to determine the extractant concentrations of

phosphorus after their absorbance was obtained in the spectrophotometer.

A total of 12 samples were measured for phosphorus, with one or more samples taken from

each site (fig. 32) and more than one sample taken over the four main sample days; 14th

August, 17th August, 19th August and 22nd August (fig. 33).

Figures 32 and 33 | A) Number of samples collected per site and analysed for phosphorus concentration. Each sample was

collected at each site on a different day (either; 14/08/15, 17/08/15, 19/08/15 or 22/08/15 except for a duplicate sample

(included in the graph) collected on the 14/08/15. B) Number of samples collected on each main sampling day (at all sites)

and analysed for phosphorus concentration.

There were three main stages of phosphorus (P) extraction. The first stage (NH4Cl), extracts

the loosely bound phosphorus (highly labile P) from the sediment. The second (NaOH),

extracts phosphorus that is bound to Fe and Al oxyhydroxides (moderately labile) and finally,

the third stage (HCl), extracts the calcite- and apatite-bound phosphorus (refractory and less

reactive). It is also important to note that the results in this section pertain to the extractable

labile particulate P only. Organic-bound phosphorus (residual phosphorus) were not taken

into account. Similarly, dissolved P (present in meltwaters) is also not analysed here.

Total phosphorus (TP) is the value given to the total amount of phosphorus in glacial runoff,

including; soluble reactive phosphorus (SRP), dissolved phosphorus in glacial meltwaters and

particulate phosphorus (sediment-bound). In this analysis, the focus is solely on particulate

phosphorus, so the abbreviation TP, in the case of this paper, refers to the total particulate


67 | P a g e

phosphorus, denoted (from here onwards) as TPP – referring only to the phosphorus bound to

the sediment. However, TPP in this paper does not refer to organic-bound and residual

phosphorus that can be extracted using sulphuric acid/potassium persulphate solution and

then autoclaved (Hawkings, et al. 2016).

Of the total particulate phosphorus7 (TPP), the loosely-bound (highly labile) P (NH4Cl) made

up 10% of TPP, the moderately labile, Fe- and Al- oxyhydroxide bound P (NaOH) made up

~27% TPP and the refractory Ca- and Mg- bound P (HCl) made up ~63% TPP.

4.4.1 Particulate phosphorus concentration at each site (spatial distribution)

Figure 34 | Concentrations of phosphorus for each extractant phase (NH4Cl, NaOH and HCl) at each sample site (excluding

site 7). All samples were taken on the same day (17/08/15) to observe phosphorus concentrations spatially by eliminating

temporal variation.

Site 3 showed the greatest concentrations of phosphorus for the loosely bound fraction,

suggesting that sediment and meltwater influx to the valley from the smaller glacier (Nordre

Bayfjellbreen), adjacent to Bogerbreen, could support greater concentrations of phosphorus.

Whilst sediment also increases between site 1 and site 3, the increase in phosphorus

7 Excluding the residual and organic-bound phosphorus


68 | P a g e

concentration cannot be directly linked to sediment flux because if that were the case,

phosphorus concentrations would be higher at site 4, as reflected in sediment flux (fig. 17).

The spatial pattern of phosphorus concentration throughout the valley is very similar to the

trend associated with the percentage of carbon in the sediment (fig. 24). This relationship

appears to be more rational as both carbon and phosphorus components are subject to

erosional processes dictated by meltwater flux. Regardless of sediment quantity (although it

will have some influence of nutrient flux), the availability of nutrients will depend on nutrient

form and sediment grain reactivity. At sites in the valley where other nutrient concentrations

are high (phosphorus and carbon), it may suggest that the suspended sediment in the small

runoff from the Nordre Bayfjellbreen tributary may possess higher grain reactivity’s.

However, it cannot be ruled out entirely that suspended sediment flux and the quantity of

sediment does not impact phosphorus concentration in some way (as attributed by the high

concentrations of phosphorus in site 7 [compared to other sites] in fig. 35).

Figure 35 | Average phosphorus concentration for all sample sites in the Endalen glacial valley.

Interestingly, there appears to be little relationship between the three types of P (highly labile,

moderately labile and refractory). At site 7, where refractory (less reactive) phosphorus is


69 | P a g e

greatest, concentrations of labile P do not exhibit the same high values in comparison to other

sites. Moderately labile P is greatest at site 4 (but lowest at site 3) and highly labile P is

greatest at sites closest to the glacier.

Although the variations in particulate phosphorus do not vary greatly spatially, the

differences in P concentrations (and their labile states) differ spatially. This could be

attributed to sediment flux (as supported by high refractive P at site 7, where sediment is

greatest), however this could also be due to a single reading (as opposed to more readings and

averages obtained for other sites). Another reason for the slight variability could be related to

meltwater flux. For future studies in the Endalen glacial valley, it would be interesting to see

whether dissolved phosphorus values change, as a result of meltwater discharge, as well as

total phosphorus in the form of residual and organic-bound P. Studies by Hawkings, et al.

(2016) have highlighted to relationship of the meltwater flux and P export from the

Greenland ice sheet. During 2012, enhanced P export coincided with large meltwater

discharge events, demonstrating the importance of subglacial flow to P export (Hawkings, et

al. 2015; 2016). Similarly, an improvement on the study will involve recording TP

(dissolved, particulate and residual P) – i.e. total soluble reactive phosphorus (total SRP) and

meltwater discharge over long timescales to observe seasonal trends in P flux. This will

determine whether sediment flux or meltwater flux has a greater impact on P export (whether

subglacial erosion, controlled by meltwater quantity and pressure, is the primary control of P

export [observed through seasonal changes in meltwater discharge events] or whether

sediment flux, indirectly controlled by meltwater discharge but also spatial sources of

geology), dictate P availability).


70 | P a g e

4.4.2 Phosphorus concentration through time (temporal distribution)

Samples of phosphorus (P) were analysed in sediments collected on; 14th August, 17th

August, 19th August and 22nd August, 2015.

Figure 36 | Average concentrations of particulate phosphorus for each main sample period. Note that only one sample was

taken on 22nd August, whereas multiple samples were taken on other dates.


71 | P a g e

Figure 37 | Particulate phosphorus concentrations for each extractant at different sites in the valley, over the four main

sample collection dates.

The spatial trend of particulate phosphorus concentration in the Endalen glacial valley was

very vague, however, the average temporal P flux, shows a stronger trend (fig. 36). As time

progresses, phosphorus concentration (particularly the refractory P) decreases. The other,

more labile P fluxes, appear to remain the same over time, similar to their spatial distribution,

however, this could be attributed to their low concentrations in comparison to refractory P.

4.4.3 Discussion of refractory and moderately labile P variability

The Endalen glacial valley is dominated by carbonates, which have a strong capacity to retain

phosphorus (Zhang, et al. 2004). Therefore, it is no surprise that the greatest fraction of

sediment-bound phosphorus is the Ca- Mg- bound P (HCl). When exposed to physical

weathering from glacial mass fracturing, and chemical weathering, as a result of meltwater


72 | P a g e

flow, calcium ions (Ca2+) are produced from carbonates. Phosphorus reacts with these ions

and can become bound to them. The adsorption of phosphate within carbonates is a direct

result of a chemical equilibrium between dissolved orthophosphate (PO43-) and calcium-

bound phosphate (moderately labile), mediated by pH (which can be moderated by nitrite

accumulation in meltwaters) and aerobic environments (Monroy-Ríos and Beddows, 2012).

Studies by Monroy-Ríos and Beddows (2012) have shown that phosphate adsorption (to

carbonate sediment) occurs under fresh water conditions (low salinity) and desorption of

phosphorus, occurs when salinity increases, as it dissolved out of the carbonate matrix.

Therefore, as a result of fresh glacial meltwater runoff, phosphorus ions can be adsorbed to

calcium ions (liberated from carbonates) and once they enter the coastal fjord

(Adventfjorden), the phosphorus is bioavailable for marine organisms, particularly plankton.

It would be interesting to continue with further studies to determine the spatial distribution of

phosphorus by adapting studies conducted by Zhang, et al. (2004) to Endalen and perhaps

even Adventdalen, which leads out into Adventfjorden. By dividing phosphorus into more

fractions; ‘authigenic carbonate fluorapatite’, ‘biogenic apatite’ and ‘CaCO3-bound P’ for

example, as well as noting the proportions of inorganic and organic phosphorus, it would be

interesting to note to see whether there are further trends or fluctuations of moderately labile

P in downstream environments.

The second greatest sediment-bound phosphorus fraction in the valley is moderately labile

Fe- Al- oxyhydroxide bound P (NaOH-P). The spatial controls on NaOH-P are most likely

due to the lithology of Endalen. The physical and chemical weathering of shales, sandstones

and carbonates in the valley produce pyrite. The abundance of NaOH-P, therefore, will be

primarily controlled by meltwater access and pressure (driving weathering and erosional

forces), producing ferric oxyhydroxides from pyrite (eq. 1 and 2) which inorganic phosphorus

binds to. Summarily, the combination of pyrite supply (controlled by geology), ferric

oxyhydroxide production (controlled by chemical weathering) and the temporal factors

dictating meltwater discharge (length of melt season), are the primary controls on moderately

labile (NaOH) P flux in Endalen.


73 | P a g e

CHAPTER 5 SUMMARY


Provide a summary of the key findings for each of the variables considered in data

analysis

Present recommendations for improvements to the project and potential future

research ideas

This project set out to investigate the spatial and temporal distribution of suspended sediment

throughout the Endalen glacial valley, as well as consider the implications sediment flux has

on nutrient concentrations delivered to downstream environments.

5.1. Summary of suspended sediment flux

Analysis of suspended sediment flux over time showed that sediment remained relatively

constant throughout the valley despite some variation in sediment flux from site to site. The

greatest quantities of suspended sediment occurred in the early sampling periods (early-mid

August). Spatial distribution of sediment flux in the valley showed that larger quantities of

sediment were observed in the middle (site 4) and near the mouth (site 7) of the valley. There

was also a significant increase in suspended sediment between the base of the Bogerbreen

glacier (site 1) and post-Nordre Bayfjellbreen tributary (site 3), suggesting that the smaller

adjacent glacier contributes some sort of sediment flux despite its size. However, this is an

uncertain theory that requires future investigation as smaller polythermal glaciers exhibit

cold-base characteristics, reducing sediment erosion and preventing subglacial flow.

5.2. Summary of elemental nitrogen and carbon concentrations

Analysis of elemental nitrogen and carbon in the suspended sediment showed a peak in

values after the tributary at site 3, further supporting the suggestion that Nordre Bayfjellbreen

contributes to suspended sediment flux and/or glacial runoff in the Endalen valley to some

extent. There was little spatial variation in % C and % N throughout the valley (with the

exception of site 1). This means that sediment samples used for elemental analysis can be

taken from anywhere in the proglacial valley and will provide a representation of the C:N

CHAPTER 5 SUMMARY

74 | P a g e

ratio values of the entire valley. Finally, values of % C and % N were above the critical

limiting values (8.8 and 1.14 respectively), stating that the Endalen valley is not a carbon-

limiting nor a nitrogen-limiting environment.

5.3 Glacial hydrochemistry and major ion analysis summary

Analysis of glacial meltwater hydrochemistry shows that, contrary to high suspended

sediment flux, high ion concentrations occurred in mid-late August (22nd August), rather than

earlier on in the sampling period (14th August). The presence of high concentrations of

sulphate ions suggest the potential for sulphate reduction in either oxic or anoxic conditions,

the latter of which, seems the most probable because Bogerbreen (a relatively small

polythermal glacier) is predominantly cold-based, which limits oxygenated subglacial water

flow. Alternatively, the presence of sulphate reducing bacteria (SRB) may also attest to the

elevated sulphate levels (Wadham, et al. 2004). Spatial distributions of nitrate may be related

to calcium (Ca2+) and magnesium (Mg2+) cation availability. Elevated concentrations of

major ions in the non-glacial valley Gruvendalen requires further investigation. Nitrite

concentrations (which decrease in Gruvendalen), may suggest the presence of nitrogen-fixing

bacteria in supraglacial or subglacial environments. Finally, the relatively high Ca2+

concentration reflects carbonate rock reactivity and suggests that calcium-bound phosphorus

is likely considering plentiful calcium cation supply.

5.4 Summary of particulate phosphorus flux

Total particulate phosphorus (P) (excluding residual organic-bound P) remained relatively

constant throughout the Endalen glacial valley. Spatial trends of P are similar to elemental (%

C and %N) concentrations, highlighting elevated levels at tributary (Nordre Bayfjellbreen).

Concentrations of refractory (calcite- apatite- bound) P were the greatest, attested by the

calcite and apatite rich geological sources in the valley from the Mijenford and Adventdalen

lithological groups. Concentrations of moderately labile (Ca- and Fe- oxyhydroxide bound) P

were also relatively moderate to high, reflecting the geology of the valley dominated by

carbonates. Loosely adsorbed P was present in small concentrations. The temporal

distributions of P concentrations showed a decrease in the refractory P over time, which

CHAPTER 5 SUMMARY

75 | P a g e

could be a result of decreased meltwater flow as the temperatures drop and the melt season

comes to an end.

5.5 Recommendations for project improvements and further analysis

Meltwater flow dynamics seem to feature in all components of analysis. Therefore,

recommendations for further analysis include measurements of meltwater discharge over long

time periods (seasonal and annual) to observe trends in meltwater discharge and whether they

correspond to responses in nutrient flux, specifically phosphorus, carbon and nitrogen. Noting

meltwater discharges of glacial runoff at different locations in the valley (including the

Nordre Bayfjellbreen tributary) would help examine spatial trends.

Analysing grain sizes of suspended sediment would also provide an additional component to

help explain, or better identify, spatial and temporal trends in nutrient sediment flux in the

valley. Grain size analysis could highlight whether increased nutrient flux occurred in larger

or smaller grain sizes. Additionally, by adapting grain reactivity studies (exercised by

Chutchcharavan and Aciego, 2014) to grain size and nutrient concentration findings, it would

be possible to see whether grain reactivity is primarily a function of size. Furthermore,

extending more sample sites of the Endalen valley into Adventdalen (and along it towards

Adventfjorden) would be able to show whether nutrient concentrations in the sediment

remain the same as in the valleys and whether they are transported in uniform concentrations

to the fjord, or whether organisms in the braided river systems utilise the nutrients.

Finally, considering recent breakthroughs in understanding the concentrations of glacial and

ice sheet runoff (Hawkings, et al. 2016), it would be worth considering the dissolved P

fraction of meltwaters, as well as the residual, organic-bound P, in order to determine total

phosphorus (TP) flux and total soluble reactive phosphorus (SRP) both in the Endalen glacial

valley, the non-glacial Gruvendalen and the downstream Adventdalen.

CHAPTER 5 SUMMARY

76 | P a g e

REFERENCES

Anderson, S. P. (2005) Glaciers show direct linkage between erosion rate and chemical

weathering fluxes. Geomorphology. 67(1-2), pp. 147–157.

Anesio, A. M., Hodson, A. J., Fritz, A. Psenner, R., and Sattler, B. (2009) High microbial

activity on glaciers: importance to the global carbon cycle. doi: 10.1111/j.1365-

2486.2008.01758.x

Aschwanden, A. and Blatter, H. (2005) Meltwater production due to strain heating in

Storglaciaren, Sweden. Journal of Geophysical Research. 110 F04024.

Atkins, C. B. Barrett, P. J. and Hicock, S. R. (2002) Cold glaciers erode and deposit:

evidence from Allan Hills, Antarctica. Geology, 30(7), pp. 659-662.

Beince, H. J., Domine, F., Ianniello, A., Nardino, M., Allegrini, I., Teinila, K. and Hillamo,

R. (2003) Fluxes of nitrates between snow surfaces and the atmosphere in the European high

Arctic. Atmospheric chemistry and physics. 3, pp. 335-346.

Benn, D., Gulley, J., Luckman, A., Adamek, A., Glowacki, P. S. (2009) Englacial drainage

systems formed by hydrologically driven crevasse propagation. Journal of Glaciology,

55(191), pp. 513-523.

Benn, D. I. and Evans, D.J.A. (2010) Glaciers & Glaciation. London: Hodder Education,

802.

Benn, D. and Evans, D. J. A. (2014) Glaciers and Glaciation 2nd Edition. Routledge.

Benitez-Nelson, C. R. (2000) The biogeochemical cycling of phosphorus in marine systems.

Earth Science Reviews. 51, pp. 109-135.

Bhatia, M.P., Das, S.B., Xu, L., Charette, M.A., Wadham, J.L. and Kujawinski, E.B. (2013)

77 | P a g e

Organic carbon export from the Greenland ice sheet. Geochim Cosmochim Ac 109,

329-344.

Bingham, R. G. et al. (2006) Hydrology and dynamics of a polythermal (mostly cold) High

Arctic glacier. Earth Surface Processes and Landforms. 31, pp. 1463-1479.

Bogen, J. (1996) Erosion rates and sediment yields of glaciers. Annals of Glaciology. 22, pp.

48-52.

Bogen, J. and Bønsnes, T. E. (2003) Erosion and sediment transport in High Arctic rivers,

Svalbard. Polar Research. 22(2), pp. 175-189.

Bottrell, S. H. and Tranter, M. (2002) Sulphide oxidation under partially anoxic conditions at

the bed of the Haut Glacier d’Arolla, Switzerland. Hydrological Processes. 16, pp. 2363–

2368.

Butcher, S. S., Charlson, R. J., Orians, G. H. and Wolfe, G. Y. (1992) Global biogeochemical

cycles. Academic Press.

Chutcharavan, P. M. and Aciego, S. M. (2014) Surface area characterization of suspended

sediments in glacial meltwater using “nano-BET”. Senior Honors thesis Dept. Earth and

Environmental Sciences. University of Michigan.

Copland, L., Martin, S. and Peter, N. W. (2003) Links between short-term velocity variations

and the subglacial hydrology of a predominantly cold polythermal glacier. Journal of

Glaciology. 49(166), pp. 337-348.

Crocket, K. C., Vance, D., Foster, G. L., Richards, D. A. and Tranter, M. (2012) Continental

weathering fluxes during the last glacial/interglacial cycle: insights from the marine

sedimentary Pb isotope record at Orphan Knoll, NW Atlantic. Quaternary Science Reviews.

38(0), pp. 89-99.

78 | P a g e

Cuffey, K. M. and Paterson, W. S. B. (2010) The Physics of Glaciers, 4th edition. Academic

Press, 704.

Davies, B. (2014) Glacial thermal regime. [Online] Available at:

http://www.antarcticglaciers.org/modern-glaciers/glacial-processes/ Accessed on: 12/03/16.

Davies, L. M. T., Atkins, C. B., Van der Meer, J. J. M., Barrett, P. J. and Hicock, S. R. (2009)

Evidence for cold-based glacial activity in the Allan Hills, Antarctica. Quaternary Science

Reviews, 28(27-28), pp. 3124-3137.

De Baar, H. J. W., De Jong, J. T. M., Bakker, D. C. E., Löscher, B. M. Veth, C., Bathmann,

U. and Smetacek, V. (1995) Importance of iron for plankton blooms and carbon dioxide

drawdown in the Southern Ocean. Nature. 373, pp. 412-415.

Diersing, N. (2009) Phytoplankton blooms: the basics. Florida Keys National Marine

Sanctuary.

Dobhal, D. P. (2014) Englacial Conduit. Encyclopedia of Snow, Ice and Glaciers

Part of the series Encyclopedia of Earth Sciences Series, pp. 257-257.

Elverhøi, A., Svendsen, J. I., Solheim, A., Anderson, E., Milliman, J., Mangerud, J., Hooke,

R., LeB, R. (1995) Late quaternary sediment yield from the high Arctic Svalbard area.

Journal of Geology. 103, pp. 1-17.

Evans, D. J. A., Phillips, E. R., Hiemstra, J. F. and Auton, C. A. (2006) Subglacial till:

Formation, sedimentary characteristics and classification. Earth-Science Reviews, 78(1-2),

pp. 115-176.

Follmi, K.B., Hosein, R., Arn, K. and Steinmann, P. (2009) Weathering and the mobility of

phosphorus in the catchments and forefields of the Rhone and Oberaar glaciers, central

Switzerland: Implications for the global phosphorus cycle on glacial-interglacial

timescales. Geochim Cosmochim Ac 73, 2252-2282.

79 | P a g e

Fountain, A. G. and Walder, J. S. (1998) Water flow through temperate glaciers. Reviews in

Geophysics. 36(3), pp. 299-328.

Geilhausen, M., Otto, J-C. and Schrott, L. (2009) Sediment budgets for two glacier forefields

(Pasterze & Obersulzbachkees, Hohe Tauern, Austria) - conceptual approach & first results.

4th Symposium of the Hohe Tauern National Park Conference Volume for Research in

Protected Areas, pp. 97-101.

Glasser, N. F. et al. (2003) The origin and significance of debris-charged ridges at the

surface of Storglaciaren, northern Sweden. Geography Annual Series. 85(2), pp. 127-147.

Goodsell, B., Hambrey, M. J. and Glasser, N. F. (2005) Debris transport in a temperate valley

glacier: Haut Glacier d’Arolla, Valais, Switzerland. Journal of Glaciology, 51(172), pp. 139-

146.

Gooseff, M. N., McKnight, D., Runkel, R. L. and Duff, J. H. (2004) Denitrification and

hydrologic transient storage in a glacial meltwater stream, McMurdo Dry Valleys, Antarctica.

Limnology Oceanography. 49(5), pp. 1884-1895.

Gooseff, M., McKnight, D. M. and Runkel, R. L. (2004) Reach-Scale Cation Exchange

Controls on major ion chemistry of an Antarctic glacial meltwater stream. Aquatic

Geochemistry. 10, pp. 221-238.

Graham, W. F. and Duce, R. A. (1971) Atmospheric pathways of the phosphorus cycle.

Geochimica et Cosmochimica Acta. 43, pp. 1195-1208.

Graham, W. F. and Duce, R. A. (1981) Atmospheric input of phosphorus to remote tropical

islands. Pacific Science. 35, pp. 241-255.

Graham, W. F. and Duce, R. A. (1982) The atmospheric transport of phosphorus to the

Western North Atlantic. Atmospheric Environment. 16, pp. 1089-1097.

80 | P a g e

Grasby, S., Allen, C. C., Longazo, T. G., Lisle, J. T., Griffin, D. W. and Beauchamp, B.

(2003) Supraglacial sulphur springs and associated biological activity in the Canadian High

Arctic – signs of life beneath the ice. Astrobiology. 3, pp. 583-596.

Gulley, J. D. et al. (2009) A cut-and-closure origin for englacial conduits in uncrevassed

regions of polythermal glaciers. Journal of Glaciology. 55(189), pp. 66-80.

Haeberli, W., Hoelzle, M., Paul, F., Zemp, M (2007) Integrated monitoring of mountain

glaciers as key indicators of global climate change: the European Alps. Annals of Glaciology,

46(1), pp. 150-160.

Hagen, J. O., Kohler, J., Melvold, K., Winther, J. G. (2003) Glaciers in Svalbard: mass

balance, runoff and freshwater flux. Polar Research Papaers. 22, pp. 145-159.

Hallet, B., Hunter, L. and Bogen, J. (1996). Rates of erosion and sediment evacuation by

glaciers: A review of field data and their implications. Global and Planetary Change. 12, pp.

213-235.

Hambrey, M. J. and Fitzsimons, S. J. (2010) Development of sediment-landform associations

at cold glacier margins, Dry Valleys, Antarctica. Sedimentology, 57, pp. 857-882.

Hawkings, J., Wadham, J.L., Tranter, M., Raiswell, R., Benning, L.G., Statham, P.J.,

Tedstone, A. and Nienow, P. (2014) Ice sheets as a significant source of highly

reactive nanoparticulate iron to the oceans. Nature Communications 5.

Hawkings, J.R., Wadham, J.L., Tranter, M., Lawson, E., Sole, A., Cowton, T., Tedstone,

A.J., Bartholomew, I., Nienow, P., Chandler, D. and Telling, J. (2015) The effect of

warming climate on nutrient and solute export from the Greenland Ice Sheet.

Geochemical Perspectives Letters 1, 94-104.

Hawkings, J. (2016) Biogeochemical cycles. Blogs of the Euopean Geoscience Union.

Available online: http://blogs.egu.eu/divisions/cr/tag/biogeochemical-cycles/ [Accessed on:

02/04/16]

81 | P a g e

Hawkings, J., Wadham, J., Tranter, M., Telling, J., Bagshaw, E., Beaton, A., Simmons, S.,

Chandler, D., Tedstone, A. and Nienow, P. (2016) The Greenland ice sheet as a hotspot of

phosphorus weathering and export in the Arctic. Global Biogeochemical Cycles, doi:

10.1002/2015GB005237.

Hodgkins, R. (1997) Glacier hydrology in Svalbard, Norwegian High Arctic. Quaternary

Science Reviews, 16, pp. 957-973.

Hodgkins, R., Tranter, M. and Dowdeswell, J. A. (1998) Solute provenance, transport and

denudation in a high-Arctic glacierised catchment. Hydrological Processes. 11(4), pp. 1813-

1832.

Hodgkins, R. (2001) Seasonal evolution of meltwater generation, storage and discharge at a

non-temperate glacier in Svalbard. Hydrological Processes. 15(3), pp. 441-460.

Hodgkins, R., Cooper, R., Wadham, J. and Tranter, M. (2003) Suspended sediment fluxes in

a high-Arctic glacierised catchment: implications for fluvial sediment storage. Sedimentary

Geology. 162, pp. 105-117.

Hodgkins, R., Cooper, R., Wadham, J. and Tranter, M. (2009) The hydrology of the

proglacial zone of a high-Arctic glacier (Finsterwalderbreen, Svalbard): Atmospheric and

surface water fluxes. Journal of Hydrology. 378, pp. 150-160.

Hodson, A. J. (1994) Climate, hydrology and sediment transfer process interactions in a sub-

polar glacier basin, Ph.D. thesis, University of Southampton.

Hodson, A., J. and Ferguson, R., I. (1999) Fluvial suspended sediment transport from cold

and warm-based glaciers in Svalbard. Earth Surface Processes and Landforms. 24, pp. 957-

974.

Hodson A., Tranter M., Gurnell A., Clark M. and Hagen, J.O. (2002) The hydrochemistry of

Bayelva, a high Arctic proglacial stream in Svalbard. Journal of Hydrology. 257, pp. 91-114.

82 | P a g e

Hodgkins, R., Cooper, R., Wadham, J., and Tranter, M. (2009) The hydrology of the

proglacial zone of a high-Arctic glacier (Finsterwalderbreen, Svalbard): Atmospheric and

surface water fluxes. Journal of Hydrology. 378, pp. 150-160.

Hodson, A., Mumford, P. and Lister, D. (2004) Suspended sediment and phosphorus in

proglacial rivers: bioavailability and potential impacts upon the P status of ice-marginal

receiving waters. Hydrological Processes. 18, pp. 2409-2422.

Hodson, A. et al. (2005) Multi-year water and surface energy budget of a high-latitude

polythermal glacier: Evidence for overwinter storage in a dynamic subglacial reservoir.

Annals of Glaciology. 42(1), pp. 42-46.

Hodson, A. J., Mumford, P. N., Kohler, J. and Wynn, P. M. (2005b) The high Arctic glacial

ecosystem: new insights from nutrient budgets. Biogeochemistry. 72(2), pp. 233-256.

Hodson, A. (2006) Biogeochemistry of snowmelt in an Antarctic glacial ecosystem. Water

Resources Research. 42.

Hodson, A. (2007) Phosphoru s in Glacial Meltwaters, Glacier Science and Environmental

Change. Blackwell Publishing, pp. 81-82.

Hodson, A., Anesio, A.M., Tranter, M., Fountain, A., Osborn, M., Priscu, J., Laybourn-Parry,

J. and Sattler, B. (2008) Glacial ecosystems. Ecol Monogr 78, 4 1-67.

Hodson, A., Nowak, A. and Christiansen, H. (2015) Glacial and periglacial floodplain

sediment regulate hydrological transfer of reactive iron to a high Arctic fjord. Accepted

article undergoing peer review.

Holmlund, P. (1998) Internal geometry and evolution of moulins, Storglaciaren, Sweden.

Journal of Glaciology. 34(117), pp. 242-248.

Holtermann, C. (2007) Flow conditions within englacial drainage channels. M.Sc. Thesis.

University of Science and Technology, Norway, pp. 72.

83 | P a g e

Hooke, R. L. and Pohjola, V. A. (1994) Hydrology of a segment of a glacier situated in an

overdeepening, Storglaciaren, Sweden. Journal of Glaciology. 40(134), pp. 140-148.

Howarth, R. W., Jensen, H. S., Marine, R. and Postma, H. (1995) Transport to and processing

of P in nearshore and oceanic waters. In: Phosphorus in the Global Environment. Wiley, New

York, pp. 323-328.

Irvine-Fynn, T. D. L. (2006) Seasonal changes in ground-penetrating radar signature

observed at a polythermal glacier, Canada. Earth Surface Processes Landforms. 31, pp. 892-

909.

Irvine-Fynn, T. D. L., Hodson, A. J., Moorman, B. J., Vatne, G. and Hubbard, A. L. (2011)

Polythermal glacier hydrology. Reviews of Geophysics. 49, RG4002,

DOI:10.1029/2010RG000350.

Jacobson, M., Charlson, R. J., Rodhe, H. and Orians, G. H. (2000) Earth System Science:

From Biogeochemical Cycles to Global Changes. Academic Press.

Jones, M. T., Pearce, C. R., Jeandel, C., Gislason, S. R., Eriksdottir, E. S., Mavromatis, V.

and Oelkers, E. H. (2012) Riverine particulate material dissolution as a significant flux of

strontium to the oceans. Earth Planetary Science Letters. 355-356, pp. 51-59.

Karl, D. M. and Yanagi, K. (1997) Partial characterisation of the dissolved organic

phosphorus pool in the oligotrophic North Pacific Ocean. Limnology Oceanography. 42, pp.

1398-1405.

Kendall, C. G. (1992) Sedimentary Basins: Evolution, Facies and Sediment Budget by

Gerhard Einsele. Springer Verlag, Berlin, IBSN 3-540-54743.

Koppes, M. N. and Hallet, B. (2002) Influence of rapid glacial retreat on the rate of erosion

by tidewater glaciers. Geology. 30, pp.47-50.

84 | P a g e

Kozoil, K., Kozak, K. and Polkowska, Z. (2014) Superimposed Ice as Nutrient Storage. Fifth

International Conference on Environmental Science and Technology. 69(4). DOI:

10.7763/IPCBEE.

Kumar, K., Miral, M. S., Joshi, V. and Panda, Y. S. (2002) Discharge and suspended

sediment in the meltwater of Gangtori Glacier, Garhwal Himalaya, India. Hydrological

Sciences Journal, (47(4), pp. 611-619.

Lawson, E., Wadham, J.L., Tranter, M., Stibal, M., Lis, G., Butler, C., Laybourn-Parry, J.,

Nienow, P., Chandler, D. and Dewsbury, P. (2013) Greenland Ice Sheets exports

labile organic carbon to the Arctic oceans. Biogeosciences Discussions 10, 19311–

19345.

Lorraine, R. D. and Fitzsimons, S. J. (2014) Cold-Based Glaciers. Encyclopedia of Snow, Ice

and Glaciers. Part of the series Encyclopedia of Earth Sciences Series, pp. 157-161.

Macheret, Y. Y., Zhuravlev, A. B. (1982) Radio echo-sounding of Svalbard glaciers. Journal

of Glaciology. 28(99), pp. 295–314.

Mavlyudov, B. R. (1994) Problems of en- and subglacial drainage origin, in Actes du 3

Symposium International GLACKIPR (Processings of the 3rd International GLACIPR

Symposium). 561, pp. 77-82.

Mavlyudov, B. R. (2005) About a new type of englacial channels, Spitsbergen, in glacier

caves and glacial karst in High mountains and Polar Regions: Proceedings 7th GLACKIPR

Conference, pp. 54-60.

Meis, S., Spears, B. M., Maberly, S. C. O’Malley, M. B. and Perkins, R. G. (2012) Sediment

amendment with Phoslock in Clatto Reservoir (Dundee, UK): Investigating changes is

sediment elemental composition and phosphorus fractionation. Journal of Environmental

Management. 93, pp. 185-193.

Meybeck, M. (1976) Total mineral dissolved transport by world major rivers. Hydrological

Sciences Journal. 21(2), pp. 265-284.

85 | P a g e

Milliman, J. D. and Farnsworth, K. L. (2013) River discharge to the coastal ocean: A global

synthesis. Book: Cambridge University Press.

Monroy-Ríos, E. and Beddows, P. A. (2012) Submarine groundwater discharge of

phosphorus and iron from carbonate coastlines under rising sea levels, Yucatan, peninsula,

Mexico. Geological Society of America Abstracts with Programs. 44(7), pp.158.

Murray, T and Clarke, G. K. C. (1995) Black-box modelling of the subglacial water system.

Journal of Geophysical Research. 100(10), pp. 231-245.

National Oceanic and Atmospheric Administration. (2013) Phytoplankton are microscopic

marine plants. Florida Keys National Marine Sanctuary.

Neumann, U. (2006) Climate – glacier links on Bogerbreen, Svalbard: Glacier mass balance

investigations in central Spitsbergen 2004 / 2005. University of Oslo, Masters Thesis.

O-Farrell, C. R., Heimsath, A. M., Lawson, D. E., Jorgensen, L. M., Evenson, E. B., Larson,

G. and Denner, J. (2009) Quantifying periglacial erosion: insights on a glacial sediment

budget, Matanuska Glacier, Alaska. Earth Surface Processes and Landforms. 34(15), pp.

2008-2022.

Pandey, S. K., Singh, A. K. and Hasnain, S. I. (2002) Grain-size distribution, morphoscopy

and elemental chemistry of suspended sediments of Pindari Glacier, Kumaon Himalaya,

India. Hydrological Sciences Journal.

Porazinska, D. L, Fountain, A. G., Nylen, T. H., Tranter, M., Virginia, R. A. and Wall, D. H.

(2004) The Biodiversity and Biogeochemistry of Cryoconite Holes from McMurdo Dry

Valley Glaciers, Antarctica. Arctic, Antarctic and Alpine Research. 36(1), pp. 84-91.

Raiswell, R., Tranter, M., Benning, L. G., Siegert, M., De’ath, R., Huybrechts, P. and Payne,

T. (2006) Contributions from glacially derived sediment to the global iron (oxyhydr)oxide

cycle: Implications for iron delivery to the oceans. Geochimica et Cosmochimica Acta. 70,

pp. 2765–2780.

86 | P a g e

Redfield, A. C. Ketchum, B. H. and Richards, F. A. (1963) The influence of organisms on the

composition of seawater. The Sea Interscience, pp. 26-77.

Repp, K. (1988) The hydrology of Bayelva, Spitsbergen. Nordic Hydrology. 19, pp. 259-268.

Resing, J. A. (1997) The chemistry of lava-seawater interactions at the shoreline of Kilauea

Volcano, Hawaii. Ph.D Thesis, University of Hawaii.

Riber, L. (2009) Paleogene depositional conditions and climatic changes of the Frysjaodden

Formation in central Spitsbergen (sedimentology and mineralogy). Unpublished University of

Oslo MSc thesis. 113.

Rippin, D. et al. (2003) Changes in geometry and subglacial drainage of Midre Lovenbreen,

Svalbard, determined from digital elevation models. Earth Surface Processes Landforms.

28(3), pp. 273-298.

Rippin, D. M. et al. (2005) Spatial and temporal variations in surface velocity and basal drag

across the tongue of the polythermal glacier midre Lovenbreen, Svalbard. Journal of

Glaciology. 51(175), pp. 588-600.

Rippin, D. M. (in progress) High Resolution Mapping of the Cold/Temperate Transition

Surface of the Polythermal Glaciers Midre Lovénbreen and Austre Lovénbreen, Svalbard.

NERC Geophysical Equipment Facility, pp. 1-6.

Roberts, M. C. (2000) Ice fracturing during jokuhlaups: Implications for englacial floodwater

routing and outlet development. Earth Surface Processes Landforms. 25, pp. 1429-1446.

Röthlisberger, H. and Lang, H. (1987) Glacier hydrology in Glacio-fluvial sediment transfer:

An Alpine perspective, pp. 207-284.

Rutter, N., Hodson, A., Irvine-Fynn, T., Solås, M. K. (2011) Hydrology and hydrochemistry

of a deglaciating high-Arctic catchment, Svalbard. Journal of Hydrology 410(1), pp. 39–50.

87 | P a g e

Schroeder, J. (1998) Hans glacier moulins observed from 1988 to 1992, Svalbard. Norwegian

Geopgraphical Journal. 52, pp. 79-88.

Scherler, D., Bookhagen, B. and Strecker, M. R. (2011) Spatially variable response of

Himalayan glaciers to climate change affected by debris cover. Nature Geoscience. 4, pp.

156-159.

Sharp, M., Tranter, M., Brown, G. H. and Skidmore, M. (1995) Rates of chemical denudation

and CO2 drawdown in a glacier-covered alpine catchment. Geology. 23, pp. 61-64.

Sharp, M., Parkes, J., Cragg, B., Fairchild, I. J., Lamb, H., and Tranter, M. (1999)

Widespread bacterial populations at glacier beds and their relationship to rock weathering and

carbon cycling. Geology. 27(2), pp. 107-110.

Singh, V. P., Singh, P. and Haritashya, U. K. (2011) Encyclopedia of Snow, Ice and Glaciers.

Springer Science and Business Media.

Skidmore, M. L and Sharp, M. J. (1999) Drainage system behaviour of a High-Arctic

polythermal glacier. Annals of Glaciology. 28, pp. 209-215.

Skidmore, M. L, Anderson, S. P., Sharp, M., Foght, J. and Lanoil, B. D. (2005) Comparison

of microbial community compositions of two subglacial environments reveals a possible role

for microorganisms in chemical weathering processes. Applied and Environmental

Microbiology. 71, pp. 6986-6997.

Stuart, G. T., Murray, N., Gamble, K. Hayes, Hodson, A. (2003) Characterisation of englacial

channels by ground-penetrating radar: An example from austre Brøggerbreen, Svalbard.

Journal of Geophysical Research. 108(B11), pp. 2525.

Sudgen, D. E. (1978) Glacial erosion by the Laurentide ice sheet. Journal of Glaciology.

20(83), pp. 367-391.

88 | P a g e

Svinth, A. A. G. (2013) A Sedimentological and Petrographical Investigation of the Todalen

Member and the Boundary Beds of the Endalen Member within the Firkanten Formation

(Paleocene) in the Central Basin of Spitsbergen, Svalbard. Unpublished Masters Thesis,

Norwegian University of Science and Technology, Norway, 163.

Syvitski, J. P. M. and Andrews, J. T. (1994) Climate change: numerical modelling of

sedimentation and coastal processes, eastern Canadian Arctic. Arctic, Antarctic and Alpine

Research. 26(3), pp. 199-212.

Syvitski, J. P. M. (2002) Sediment discharge variability in Arctic rivers: implications for a

warmer future. Polar Research. 21(2), pp. 323-330.

Tett, P. Droop, M. R. and Heaney, S. I. (1985). The Redfield Ratio and Phytoplankton

Growth Rate. Journal of the Marine Biological Association of the United Kingdom. 65, pp.

487-504.

Tranter, M. (undated). Glaciers and global biogeochemical cycles. Bristol Glaciology Centre

School of Geographical Sciences.

Tranter, M., Fountain, A., Fritsen, C., Lyons, B., Priscu, J., Statham, P., and Welch, K.

(2004) Extreme hydrochemical conditions in natural microcosms entombed within Antarctic

ice. Hydrological Processes, 18, pp. 379-387.

Tranter, M. (2005) Geochemical weathering in glacial and proglacial environments. Holland,

H. D. and Turekian, K. K. (editors). Treatise on geochemistry. 5, Elsevier, London.

Tranter, M. and the Bristol Glaciology Group. (2013). Goldschmidt Conference Abstracts,

pp. 2350.

Tyrell, T. (1999) The relative influence of nitrogen to phosphorus on oceanic primary

production. Nature. 400, pp. 525-531.

89 | P a g e

Vandeberg, G. S. and VanLooy, J. A. (2016) Continental Glacier meltwater contributions to

late summer stream flow and water quality in the northern Wind River Range, Wyoming,

USA. Environmental Earth Sciences. 75(389). DOI: 10.1007/s12665-016-5295-0.

Van der Veen, C. J. (2007) Fracture propagation as means of rapidly transferring surface

meltwater to the base of glaciers. Geophysics Research Letters. 34, L01501.

Van der Wal, R. S. W. (2008) Large and rapid melt induced velocity changes in the ablation

zone of the Greenland ice sheet. Science. 321(5885), pp. 111-113.

Vatne, G. et al. (1992) Glaciofluvial sediment transfer of a sub-polar glacier, Erikbreen,

Svalbard. Stuttgarter Geographical Studies. 117, pp. 253-266.

Vuille, M., Francou, B., Wagnon, P., Juen, I., Kaser, G., Mark, B. G. and Bradley, R. S.

(2008) Climate change and tropical Andean glaciers: Past, present and future. Earth Science

Reviews. 89, pp. 79–96.

Wadham, J. L (2001) Evidence for seasonal subglacial outburst events at a polythermal

glacier, Finsterwalderbreen, Svalbard. Hydrological Processes. 15(12), pp. 2259-2280.

Wadham, J. L., Bottrell, S. H., Tanter, M. and Raiswell, R. (2004) Stable isotope evidence for

microbial sulphate reduction at the bed of a polythermal high Arctic glacier. Earth and

Planetary Science Letters. 219, pp. 341-355.

Wasson, R. J. (2003) A sediment budget for the Ganga–Brahmaputra catchment. Current

Science. 84(8).

Waller, R.I., 2001. The influence of basal processes on the dynamic behaviour of cold-based

glaciers. Quaternary International, 86(1), pp. 117-128.

Willis, I. C. et al. (2002) Effect of snowpack removal on energy balance, melt and runoff in a

small supraglacial catchment. Hydrological Processes. 16(14), pp. 2721-2749.

90 | P a g e

Willis, I. (2008) Changing thermal regime of polythermal glaciers. Glaciers and Ice Sheets

research project. University of Cambridge, Glacial and Quaternary science thematic research

group. [Online] Available at:

http://www.geog.cam.ac.uk/research/projects/polythermalglaciers/ Accessed on: 12/03/16.

Wynn, P. M. (2004) The provenance and fate of nitrogen in Arctic glacial meltwater: An

isotopic approach. University of Sheffield Thesis.

Wynn, P. M., Hodson, A. J., Heaton, T. H. E and Chenery, S. R. (2007) Nitrate production

beneath a High Arctic glacier, Svalbard. Chemical Geology. 244(1), pp. 88-102.

Yamagata, Y., Wantanabe, H., Saitoh, M. and Namba, T. (1991) Volcanic production of

polyphosphates and its relevance to prebiotic evolution. Nature. 352, pp. 516-519.

Zaja, W. (2001) Glacial recession in Sorkappland and Central Nordenskiöldland, Spitsbergen,

Svalbard, during the 20th century. Arctic Antarctic and Alpine Research. 33(1), pp. 36-41.

Zajączkowski, M., Szczuciński, W. and Bojanowski, R. (2004) Recent changes in sediment

accumulation rates in Adventfjorden, Svalbard. Oceanologia. 46(2), pp. 217-231.

Zajączkowski, M. (2008) Sediment supply and fluxes in glacial and outwash fjords,

Kongsfjorden and Adventfjorden, Svalbard. Polish Polar Research. 29(1), pp. 59-72.

Zhang, J-Z., Fischer, C. J. and Ortner, P. B. (2004) Potential availability of sedimentary

phosphorus to sediment resuspension in Florida Bay. Global Biogeochemical Cycles. 18,

GB4008. DOI:10.1029/2004GB002255.

91 | P a g e

ACKNOWLEDGEMENTS

This project would not have been possible without the help and guidance of my project

supervisor, Dr. Liz Bagshaw of the School of Earth and Ocean Sciences at Cardiff

University. For her unending, year-long support, both pastorally and academically, as well as

supplying the sediment samples and teaching me the phosphorus extraction method.

I would also like to thank Sandra Nederbragt for her help with elemental analysis, both

preparation and running the samples in the elemental analyser. I would like to thank

Xiaohong Tang for her help with ion chromatography, preparing samples and running them.

I could not have met most of my lab work deadlines if it were not for the help and laboratory

assistance of Christina Gorringe and George Chousos.

I would like to thank my closest friends; Alexandria Rice, Zegwai Truman and Sam Roberts

for always supporting me, motivating me to meet deadlines, providing pastoral support and

well-needed humour when times seemed difficult. I would also like to thank my family for

their unending support.

Finally, I would like to thank Henrik Sass and Jen Pinnion for always being there to let me

into the laboratory when I accidentally locked myself out, or when Liz was not there to open

it.

92 | P a g e

APPENDIX

Figure A1 | Average sediment flux for each sample site for coarse and fine fraction

Figure A2 | Average sediment flux over time for coarse and fine fraction

Site

total

coarse

sed. (g)

total fine

sed. (g)

no. of

coarse

samples

no. of

fine

samples

Av. Sed.

Weight coarse

(g)

Av. Sed.

Weight fine

(g)

1 2.45 0.25 8 8 0.31 0.03

3 3.06 0.35 5 7 0.61 0.05

4 6.78 1.20 8 11 0.85 0.11

5 3.95 0.47 7 9 0.56 0.05

6 3.71 0.15 7 9 0.53 0.02

7 0.99 0.14 1 1 0.99 0.14

8 3.40 0.46 6 8 0.57 0.06

9 0.39 0.48 4 5 0.10 0.10

G1 0.00 0.01 0 1 0.00 0.01

G2 0.38 0.05 2 5 0.19 0.01

LYB1 0.00 0.00 0 1 0.00 0.00

LYB2 0.00 0.00 0 1 0.00 0.00

LYB3 0.00 0.00 0 1 0.00 0.00

Date

total

coarse

sed. (g)

total fine

sed. (g)

no. of

coarse

samples

no. of

fine

samples

av. Sed.

Weight

coarse

(g)

av. Sed.

Weight

fine (g)

14/08/2015 5.18 0.84 5 5 1.04 0.17

17/08/2015 7.11 1.15 5 5 1.42 0.23

18/08/2015 0.25 0.09 1 3 0.25 0.03

19/08/2015 2.64 0.31 4 5 0.66 0.06

20/08/2015 0.29 0.05 1 1 0.29 0.05

22/08/2015 1.74 0.18 6 6 0.29 0.03

24/08/2015 5.56 0.31 12 12 0.46 0.03

25/08/2015 0.88 0.13 3 3 0.29 0.04

30/08/2015 0.13 0.06 7 8 0.02 0.01

31/08/2015 0.39 0.04 4 4 0.10 0.01

03/09/2015 0.00 0.01 0 5 0.00 0.00

04/09/2015 0.00 0.38 0 2 0.00 0.19

05/09/2015 0.00 0.00 0 3 0.00 0.00

07/09/2015 0.00 0.01 0 5 0.00 0.00

93 | P a g e

Figure A3 | Elemental analysis data

Figure A5 | Major cations for each sample site (excluding G1 and Longyearbyen) arranged in order of site location

Site Date Amount (mg) 15N (permil air) 13C (VPDB) %N %C C/N

1 19/08/2015 25.15 0.64 -27.01 0.09 1.12 14.84

3 24/08/2015 23.10 1.03 -26.57 0.13 2.74 24.10

4 14/08/2015 24.27 1.20 -26.35 0.12 2.44 24.06

5 19/08/2015 24.22 0.67 -26.68 0.08 1.60 22.74

6 24/08/2015 25.12 1.18 -26.25 0.11 2.08 22.96

7 14/08/2015 25.92 1.40 -26.39 0.09 1.70 21.94

8 17/08/2015 24.99 1.54 -26.76 0.08 1.63 23.92

st. dev. 0.02 0.51 3.05

Site date Na+ K+ Mg2+ Ca2+

BLK 22/08/2015 n.a. n.a. 0.2197 0.20

1 17/08/2015 2.15 0.43 1.35 1.90

1 19/08/2015 4.96 0.57 3.12 4.53

1 22/08/2015 11.55 0.99 10.61 16.45

1 24/08/2015 4.59 0.55 3.38 4.92

3 14/08/2015 2.53 0.44 1.82 2.64

3 24/08/2015 3.49 0.62 3.70 6.07

3 19/08/2015 4.24 0.60 3.26 4.91

3 17/08/2015 2.51 0.52 1.68 2.58

3 22/08/2015 6.02 0.93 7.70 13.44

4 14/08/2015 2.03 0.62 2.42 4.12

4 17/08/2015 2.07 0.66 2.29 4.15

4 17/08/2015 2.12 0.67 2.12 3.60

4 19/08/2015 4.66 0.70 3.73 6.85

4 20/08/2015 6.10 0.80 5.99 11.13

4 22/08/2015 8.42 0.98 8.88 16.12

4 24/08/2015 5.22 0.73 5.03 8.92

5 24/08/2015 5.69 0.75 5.41 9.95

5 19/08/2015 4.43 0.73 3.97 7.47

6 17/08/2015 2.44 0.72 3.16 5.97

6 19/08/2015 4.79 0.81 5.56 10.83

6 22/08/2015 8.06 0.96 8.89 17.64

6 24/08/2015 6.19 0.84 7.04 13.31

7 14/08/2015 2.37 0.65 2.76 5.02

7 19/08/2015 5.17 0.78 4.90 10.05

8 17/08/2015 2.56 0.69 2.97 5.59

8 22/08/2015 7.84 0.98 9.84 20.73

8 24/08/2015 6.41 0.83 6.38 13.31

9 18/08/2015 8.18 0.95 5.88 11.65

9 25/08/2015 14.63 1.17 10.16 19.57

G2 18/08/2015 6.73 0.94 13.50 25.35

G2 22/08/2015 25.89 1.40 28.29 31.00

G2 25/08/2015 9.11 1.07 18.14 36.04

G3 18/08/2015 6.86 1.04 14.33 27.08

st. dev. 4.52 0.21 5.50 8.54

94 | P a g e

Figure A6 | Major anions for each sample site (excluding G1 and Longyearbyen) arranged in order of site location

Site date Br- Cl- Fl- NO3- NO2- PO4 3- SO4 2-

BLK 22/08/2015 n.a. n.a. n.a. 0.10 n.a. n.a. 0.04

1 17/08/2015 n.a. 0.94 0.00 0.23 1.50 n.a. 6.84

1 24/08/2015 n.a. 0.97 0.01 0.55 2.48 n.a. 22.52

1 19/08/2015 n.a. 1.63 0.01 0.53 2.75 n.a. 18.26

1 22/08/2015 0.25 2.07 0.03 1.65 4.52 0.16 81.84

3 14/08/2015 n.a. 1.25 n.a. 0.28 1.97 n.a. 9.37

3 24/08/2015 0.09 0.93 0.01 0.56 2.60 n.a. 23.99

3 19/08/2015 n.a. 1.66 0.01 0.56 2.84 n.a. 18.95

3 17/08/2015 n.a. 0.91 n.a. 0.25 2.06 n.a. 7.66

3 22/08/2015 0.12 1.74 0.02 1.00 4.31 n.a. 51.54

4 14/08/2015 n.a. 1.02 0.01 0.31 2.00 n.a. 14.69

4 17/08/2015 n.a. 0.90 0.01 0.35 2.00 n.a. 14.73

4 17/08/2015 n.a. 0.82 0.01 0.32 2.30 n.a. 11.98

4 24/08/2015 0.10 1.18 0.02 0.81 2.61 n.a. 40.64

4 22/08/2015 n.a. 1.97 0.03 1.30 4.04 n.a. 70.62

4 19/08/2015 n.a. 1.67 0.02 0.65 2.53 n.a. 27.13

4 20/08/2015 0.10 1.65 0.02 0.90 3.30 n.a. 46.40

5 24/08/2015 n.a. 1.24 0.03 0.86 2.79 n.a. 45.15

5 19/08/2015 0.10 1.66 0.01 0.70 2.67 n.a. 29.49

6 17/08/2015 n.a. 0.97 0.01 0.39 1.82 n.a. 23.85

6 19/08/2015 0.10 1.69 0.03 0.78 1.52 n.a. 50.09

6 22/08/2015 0.19 1.89 0.03 0.28 3.96 n.a. 73.47

6 24/08/2015 0.18 1.28 0.03 0.96 1.87 n.a. 61.41

7 14/08/2015 0.09 1.09 0.01 0.37 1.97 n.a. 19.86

7 19/08/2015 0.10 1.72 0.02 0.76 2.26 n.a. 42.93

8 17/08/2015 n.a. 0.98 0.01 0.40 2.17 n.a. 20.97

8 24/08/2015 0.20 1.44 0.03 1.00 2.39 n.a. 60.23

8 22/08/2015 0.22 1.97 0.04 1.34 3.54 n.a. 87.79

9 18/08/2015 0.13 6.34 0.04 0.39 2.96 n.a. 49.13

9 25/08/2015 0.26 16.78 0.04 0.72 3.03 n.a. 82.91

G2 18/08/2015 0.25 3.22 0.05 1.76 n.a. n.a. 128.48

G2 22/08/2015 0.30 2.53 0.09 2.61 0.98 n.a. 232.77

G2 25/08/2015 0.33 3.69 0.09 2.38 n.a. n.a. 180.13

G3 18/08/2015 0.28 3.23 0.05 0.36 n.a. n.a. 133.59

st. dev. 0.08 2.79 0.02 0.58 0.83 0.00 50.49

st. error 0.01 0.48 0.00 0.10 0.14 0.00 8.66

95 | P a g e

Figure A7 | Loosely bound phosphorus (NH4Cl-P) average absorbance (obtained from three readings on the

spectrophotometer), concentration of phosphorus (obtained by substituting absorbance [x] into the equation shown on the

graph)

96 | P a g e

Figure A8 | Moderately labile phosphorus (NaOH-P) average absorbance (obtained from three readings on the


graph). The absorbance of the standard solutions showed two readings that were anomalous (and another [0.8 mg/L] that did

not read at all despite numerous attempts). The anomalous results were ignored in order to meet the most suitable best fit for

the equation of the line of linear regression, hence, only standard solutions; 0.4 mg/L and 1.0 mg/L were used. Whilst this

does introduce error, it ignores the anomalous and misleading absorbance readings on other standards.

Figure A9 | Refractory (least reactive) phosphorus (HCl-P) average absorbance (obtained from three readings on the


graph). The absorbance of the standard solutions showed two readings that were anomalous (0.6 mg/L and 0.8 mg/L). The

anomalous results were ignored in order to meet the most suitable best fit for the equation of the line of linear regression,

hence, only standard solutions. Whilst this does introduce some type of bias, it ignores the anomalous and misleading

absorbance readings.

Alexandra Gorringe 1265587 MESci Dissertation

Documents

Transcript of Alexandra Gorringe 1265587 MESci Dissertation