Research Article Sedimentary Organic Matter and Phosphate ...

Research ArticleSedimentary Organic Matter and Phosphate along theKapuas River (West Kalimantan Indonesia)

Pei Sun Loh1 Chen-Tung Arthur Chen2 Gusti Z Anshari3 Jiann-Yuh Lou4

Jough-Tai Wang5 Shu-Lun Wang6 and Bing-Jye Wang2

1Department of Marine Sciences Ocean College Zhejiang University Hangzhou China2Department of Oceanography National Sun Yat-Sen University Kaohsiung Taiwan3Soil Science Department Universitas Tanjungpura Pontianak Indonesia4Department of Marine Science Republic of China Naval Academy Kaohsiung Taiwan5Department of Atmospheric Sciences and Graduate Institute of Atmospheric Physics National Central UniversityChungli Taiwan6Department of Marine Environment Engineering College of Ocean Engineering National Kaohsiung Marine UniversityKaohsiung Taiwan

Correspondence should be addressed to Pei Sun Loh pslohhotmailcom

Received 29 June 2016 Accepted 4 September 2016

Academic Editor Stanislav Franciskovic-Bilinski

Copyright copy 2016 Pei Sun Loh et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This study assessed the sedimentary organic matter (OM) and phosphate along the worldrsquos longest river on an island the KapuasRiver in West Kalimantan Indonesia The surface sediment was tested using the loss-on-ignition experiment to determine the labile OM refractory OM and total OM and the Rp values (the ratio of refractory to total OM) The CN ratios and theinorganic phosphate (IP) organic phosphate (OP) and total phosphate (TP) levels were also determinedThe combination of highRp values and low CN ratios along the upper river indicated the possible presence of relatively degraded material the low Rpvalues and high CN ratios downstream were indicative of a fresher terrestrial signal Sedimentary P levels were the highest alongthe densely populated areas downstream from the Kapuas River the second highest along themidstream river which is surroundedby oil palm plantations and the lowest along the upper river which is surrounded by forest Higher levels of OM IP OP and TPdownstream along the Kapuas River indicated the presence of anthropogenic sources of OM and P

1 Introduction

Rivers are major regulators of global climate change due totheir role as contributors to atmospheric CO

2emissions [1 2]

Rivers in turn are greatly affected by global climate changeand are consequently at risk [3] For instance increased tem-peratures affect the hydrological cycles of rivers worldwide[4] increasing river runoff in some regions of the worldwhile reducing river runoff in other regions [5 6] One of theconsequences of increasing river runoff is increased nutrientdischarge to coastal zones This has a significant impactparticularly in areas that were already receiving a high inputof nutrients from their surroundings [7] Human activitiessuch as urbanization and deforestation have resulted in anincrease in the amount of soil organic matter released into

rivers by erosion However building reservoirs has decreasedthe amount of sediment discharged into rivers and coastalzones and altered the timing of sediment discharge InIndonesia where there are few reservoirs rivers still delivera considerable amount of sediment to coastal zones [8] Thishas major consequences because Southeast Asia contains avast area of peatland [9 10] and peat soils tend to leachdissolved organic carbon (DOC) into rivers in quantitiesseveral orders of magnitude higher than nonpeat soils doConsequently tropical rivers aremajor sources of DOC to theoceans [11ndash13] this leaching is exacerbated by global climatechange because increased temperatures [14] and precipitation[15] have resulted in the increased export of DOC from peatsoils into rivers and coastal zones Currently management

Hindawi Publishing CorporationJournal of ChemistryVolume 2016 Article ID 6874234 9 pageshttpdxdoiorg10115520166874234

2 Journal of Chemistry

1 23456

78

9 10

11 1213

1415

16171819

20 21

AB

E

Kapuas River

Mempawah River

Landak River

Kapuas Kecil River

West Kalimantan

CentralKalimantan

East Kalimantan

Sarawak

Lake Sentarum

Lake Pemerak

Lake Pengembung

Kapuas Besar River

SulawesiSumatra

JavaJakarta

Irian Jaya

Malaysia Pacific Ocean

Indian Ocean

SouthChina Sea

Kalimantan

2∘309984000998400998400S

1∘209984000998400998400S

0∘109984000998400998400S

1∘09984000998400998400N

109∘20

9984000998400998400E 110

∘30

9984000998400998400E 111

∘40

9984000998400998400E 112

∘50

9984000998400998400E 114

∘00

9984000998400998400E

Figure 1 Map showing the sampling locations along the Kapuas River (which includes the Kapuas Kecil River and Kapuas Besar River) theMempawah and Landak Rivers and the Lakes Sentarum Pemerak and Pengembung

strategies to maintain the quality of river and estuary watersare more important than ever [4 16] Knowledge of sedimentorganic matter (OM) and nutrients along rivers is beneficialfor developing these management strategies

In this study surface sediments were collected from theKapuas River the Landak River and the Mempawah Riverand from the three lakes that drain into the Kapuas RiverUsing the loss-on-ignition experiment these sediments weretested to determine the labile OM refractory OMand total OM and the Rp values (the ratio of refractoryOM to total OM) Additionally inorganic phosphate (IP)organic phosphate (OP) and total phosphate (TP) levels weredetermined This study presents a profile of OM and P alonga Southeast Asian tropical river for the purpose of furtherunderstanding the dynamics of the river

2 Methods

21 Study Sites The Kapuas River is located in West Kali-mantan Indonesia With a length of 1143 km this is thelongest river in Indonesia and the worldrsquos longest river onan island Sampling was carried out from June to July 2007and December 2007 to January 2008 at the three lakes(Sentarum Pemerak and Pengembung) that drain into theupper Kapuas River at locations spanning the entire extent ofthe Kapuas River and at the Landak and Mempawah RiversDownstream Kapuas River branches into Kapuas Kecil River

and Kapuas Besar River (Figure 1) Sediment was collectedby deploying an Eijkelkamp peat sampler from a small boatinto a water depth of approximately 2m The 0ndash5 cm surfacesediment was saved for chemical analyses In the laboratorythe sediment was dried at 60∘C for a few days groundusing a mortar and pestle and sieved through a 43-meshsieve Details describing the river and sampling locationsincluding the sampling timetable and distances between thelocations and the river mouth are given by Loh et al [17 18]Detailed information on population densities wet and dryseasons and forest types (landscapes) along theKapuas Riverhydrological cycles and sediment loading have been reportedin previous studies [17 18]

22 Analytical Method The loss-on-ignition experiment wascompiled from methods used by Kristensen [19] Kristensenand Andersen [20] and Sutherland [21] A sample of approx-imately 05 g of dried ground and sieved sediment wasweighed in a crucible Crucibles with sediment were weighedand then combusted at 250∘C for 16 hours in a temperature-monitored muffle furnace When cool the crucibles werereweighed The sediment was then heated to 500∘C for 16hours When cool it was weighed again The percentageof weight reduction after reaching 250∘C is known as the labile organic matter The percentage of weight loss thatoccurs within the temperature range between 250∘C and500∘C is the refractory OMThe sum of the labile and

Journal of Chemistry 3

refractory OM is the total OMThe Rp index is the weightloss that occurs in the temperature range between 250∘C and500∘C divided by the total weight loss on ignition hence theRp value is the ratio of the refractory OM to the totalOM Kristensen [19] defined Rp as Rp = PII(PI + PII) wherePI is the weight loss that occurs after combustion in the firsttemperature range and PII is the weight loss after combustionin the second temperature range

The method used for phosphate analysis was obtainedfrom Strickland and Parsons [22] Aspila et al [23] andKoroleff [24] Dried sediment was weighed to 025 g andwashedwith 20mLof 1MHCl in a 50mL centrifuge tubeThesediment was extracted with constant shaking for 16 hoursat room temperature On the following day the supernatantwas decanted and the residue was washed with 5mL ofHCl centrifuged and combined with the supernatant forIP analysis The residue was transferred to a crucible andheated in a muffle furnace at 550∘C for two hours Whencool the residue was transferred to a centrifuge tube andextracted with 25mL of 1N HCl for 16 hours at roomtemperature with constant shaking The residue was thencentrifuged and the supernatant decanted for OP analysis Pwas analysed using themolybdenumbluemethodwith aUV-visible spectrophotometer

For the bulk elemental analysis the sediment was acid-ified with 1N HCl overnight to remove carbonates Thesediment was then rinsed with distilled water dried at60∘C and homogenized using a mortar and pestle Precisely20mg of sediment was weighed into a 4 times 4 times 11mm tinboat and crimped into a pellet The sediment was analysedfor TOC and total nitrogen (TN) using a Vario EL IIIElemental Analyzer The standard reference materials usedwere BSCC (224 TOC 024 TN) and NIST2704 (334TOC 022 TN) The average coefficients of variation foreach measurement (in duplicate and triplicate analyses) of asame-sediment sample were 232 for TOC and 308 forTN All CN ratios were calculated as TOCTN molar ratios

3 Results

Table 1 shows the results obtained for labile OM refractory OM total OM Rp values IP OP and TPThe overall reproducibility was good with the percentagereproducibility of duplicate and triplicate analyses of labileand refractory OM ranging from 002 to 641 Percentagereproducibility from duplicate analyses of P ranged from001 to 2776 Percentages of labile refractory and totalOM ranged from 161 to 1219 232 to 870 and 446 to2089 respectively Both labile and refractory OMshowed a constant range of values along the upper andmiddlesections of the Kapuas River and showed the highest valuesdownstream of the river (Figures 2(a) and 2(b)) Both thelabile and refractory fractions showed good correlations withtotal OM (Pearson correlation coefficient 119903 gt 095 119901 lt005 119899 = 21) for the June to July 2007 sample RefractoryOM was slightly higher at the upper river and lakes for theDecember 2007 to January 2008 sample hence there wasa lower but still significant (119901 lt 005) correlation betweenthe refractory fraction and labile and total OM during this

time Rp values (ratio of refractory to total OM) ranged from025 to 064 with the highest values observed in the upperriver and lakes and the lowest values observed downstream(Figure 2(c)) Rp values showed good negative correlationwith total OM (119903 gt minus07 119901 lt 005 119899 = 21) TheIP OP and TP ranged from 003 to 155mg Pg 030 to082mg Pg and 040 to 237mg Pg respectively OverallIP OP and TP had similar distribution trends to OM withslightly higher concentrations at locations downstream thanat locations along the upper river (Figure 3) TP showed abetter correlation with IP (119903 gt 09) and a poorer correlationwith OP (119903 = 06 to 08) and IP showed good correlationwith labile OM (119901 lt 005) Overall the Landak River has thehighest labile OM and the Mempawah River has higher Rpvalues than the Landak River The Landak River has higherIP OP and TP than the Mempawah River (Figures 2 and 3)

4 Discussion

41 Use of Rp Values and CN Ratios to Determine the Sourcesand Diagenesis of Sediment OM A combination of Rp valuesand CN ratios was used to further elucidate the sourcesand diagenesis of sedimentary OM along the river It wasfound that Rp values of approximately 03 are indicative ofplant material rich in carbohydrates and higher Rp valuesof approximately 06 are indicative of biogenic material ormore degradedOM Furthermore humicmaterials have highRp values and CN ratios and an advanced stage of OMdecomposition was associated with an increase in Rp valuesand a decrease in CN ratios Several scenarios based onthese combinations have been observed (i) low Rp valuesand high CN ratios may indicate terrestrial plants as theOM source (ii) increases in both Rp values and CN ratiosmay be indicative of the process of humification and (iii)high Rp values and low CN ratios may be indicative of moredegraded OM [19] These combinations were observed alongdifferent stretches of the Kapuas River Scenario (i) occurredat locations 1 through 6 along the lower Kapuas River whichshowed lower Rp values but higher CN ratios indicatingthe contribution of fresher plant material Rp values in themid- and lowerKapuasRiver and the Landak andMempawahRivers ranged from 039 to 048 also indicating fresher plantmaterial as the source of OM Scenario (ii) occurred atlocation 16 which had a high Rp value and a high CN ratioScenario (iii) was observed along the upper Kapuas River andin the lakes which had overall higher Rp values (059 to 064)and lower CN ratios this is indicative of more degradedOM material (Figures 4(a) and 4(b)) consistent with thedetection of older peat material along the upper KapuasRiver than along the lower Kapuas River [25 26] Overallthese results are in accordance with our previous findingsthat the upper Kapuas River has slightly higher values ofvanillic acidvanillin and syringic acidsyringaldehyde ratiosindicative of more degraded lignin materials compared tomidstream and downstream Kapuas River [17]

42 Phosphate in the Sediment of the Kapuas River The areassurrounding the Kapuas Kecil River were the most pop-ulated followed by the areas surrounding Kapuas Besar


Table 1 Loss-on-ignition phosphate and bulk elemental results

(a) June-July 2007 sampling

Loc Loss on ignition Phosphorus Bulk elementalLabile () Refrac () TOM () Rp IP (mgg) OP (mgg) TP (mgg) OC () TN () CN

KB1 (A) 683 plusmn 000 522 plusmn 002 1205 043 063 plusmn 001 063 plusmn 001 126 304 019 1867KB2 (B) 770 plusmn 001 494 plusmn 003 1264 039 062 plusmn 000 062 plusmn 000 124 322 020 1878KB3 (E) 610 plusmn 004 442 plusmn 004 1052 042 062 plusmn 000 039 plusmn 011 101 272 016 19831 896 plusmn 007 581 plusmn 003 1477 039 078 plusmn 000 062 plusmn 000 140 504 024 24502 860 plusmn 002 652 plusmn 001 1512 043 155 plusmn 002 082 plusmn 005 237 511 030 19873 1219 plusmn 007 870 plusmn 008 2089 042 112 078 190 888 044 23554 852 plusmn 026 532 plusmn 016 1384 038 063 plusmn 001 063 plusmn 001 126 469 022 24875 693 plusmn 002 521 plusmn 003 1214 043 062 plusmn 000 055 plusmn 011 117 332 020 18676 462 plusmn 001 377 plusmn 002 839 045 047 plusmn 000 047 plusmn 000 094 211 012 20517 563 plusmn 009 507 plusmn 007 1070 047 063 plusmn 000 055 plusmn 011 118 247 016 15178 592 plusmn 005 552 plusmn 003 1144 048 047 plusmn 000 062 plusmn 001 109 251 019 15419 669 plusmn 004 497 plusmn 002 1166 043 062 plusmn 001 062 plusmn 001 124 311 020 181410 306 plusmn 004 271 plusmn 001 577 047 039 plusmn 012 031 plusmn 000 070 136 008 198311 522 plusmn 000 367 plusmn 006 889 041 032 plusmn 000 047 plusmn 000 079 228 013 204612 413 plusmn 002 345 plusmn 001 758 046 046 plusmn 001 031 plusmn 000 077 192 011 203613 549 plusmn 002 374 plusmn 003 923 041 063 plusmn 000 047 plusmn 000 110 263 015 204614 561 plusmn 006 389 plusmn 009 950 041 063 plusmn 000 047 plusmn 000 110 277 015 215415 656 plusmn 003 445 plusmn 004 1101 040 062 plusmn 001 055 plusmn 012 117 322 021 178916 224 plusmn 003 232 plusmn 002 456 051 047 plusmn 001 031 plusmn 000 078 086 005 200717 330 plusmn 062 466 plusmn 061 796 059 031 plusmn 000 046 plusmn 000 077 194 017 133118 291 plusmn 009 429 plusmn 001 720 060 016 plusmn 000 016 plusmn 000 032 059 008 86019 265 plusmn 002 421 plusmn 002 686 061 032 plusmn 000 032 plusmn 000 064 062 009 80420 161 plusmn 002 285 plusmn 003 446 064 016 plusmn 000 031 plusmn 000 040 055 006 106921 259 plusmn 001 380 plusmn 001 639 059 031 plusmn 000 047 plusmn 000 051 104 012 1011LK1 2076 plusmn 016 681 plusmn 022 2757 025 093 plusmn 000 062 plusmn 000 155 1420 055 3012LK2 1635 plusmn 001 700 plusmn 002 2335 030 031 plusmn 001 047 plusmn 001 141 896 030 3484LK3 805 plusmn 002 456 plusmn 004 1261 036 047 plusmn 000 047 plusmn 000 094 384 017 2635MH1 657 plusmn 001 558 plusmn 003 1215 046 063 plusmn 001 031 plusmn 001 094 290 013 2603MH2 392 plusmn 054 354 plusmn 052 746 047 mdash mdash mdash 180 007 3000MH3 376 plusmn 017 399 plusmn 023 775 051 mdash mdash mdash 147 006 2858

(b) December 2007-January 2008 sampling


KB1 (A) mdash mdash mdash mdash 052 plusmn 000 061 plusmn 003 mdash mdash mdashKB2 (B) mdash mdash mdash mdash 064 plusmn 001 011 plusmn 000 mdash mdash mdashKB3 (E) mdash mdash mdash mdash 094 plusmn 001 058 plusmn 006 mdash mdash mdash1 866 plusmn 004 537 plusmn 005 1402 038 075 plusmn 000 050 plusmn 002 124 484 030 1882 608 plusmn 008 438 plusmn 001 1045 042 072 plusmn 001 050 plusmn 000 122 390 023 1983 659 plusmn 004 436 plusmn 003 1095 040 073 plusmn 000 049 plusmn 000 122 349 023 1774 1295 plusmn 007 676 plusmn 038 1971 034 023 plusmn 003 035 plusmn 000 058 924 035 3085 888 plusmn 004 485 plusmn 001 1373 035 061 plusmn 000 044 plusmn 001 105 422 027 1826 883 plusmn 003 526 plusmn 001 1409 037 074 plusmn 000 049 plusmn 000 123 501 030 1957 365 plusmn 003 472 plusmn 000 837 056 030 plusmn 000 042 plusmn 003 072 143 017 988 549 plusmn 007 442 plusmn 001 991 045 040 plusmn 001 040 plusmn 001 080 247 020 1449 274 plusmn 000 366 plusmn 000 640 057 012 plusmn 000 036 plusmn 002 049 087 014 7310 234 plusmn 002 301 plusmn 003 535 056 016 plusmn 001 028 plusmn 000 044 094 013 8411 343 plusmn 001 368 plusmn 003 711 052 026 plusmn 000 036 plusmn 000 062 134 013 12012 418 plusmn 000 394 plusmn 000 812 049 027 plusmn 000 034 plusmn 000 061 171 015 13313 541 plusmn 024 345 plusmn 011 886 039 042 plusmn 001 028 plusmn 001 069 262 016 19114 241 plusmn 015 396 plusmn 008 637 062 014 plusmn 000 040 plusmn 001 055 063 011 6715 409 plusmn 000 346 plusmn 001 755 046 050 plusmn 001 031 plusmn 001 082 196 015 15216 475 plusmn 019 401 plusmn 002 876 046 053 plusmn 001 037 plusmn 002 090 262 018 17017 519 plusmn 003 555 plusmn 018 1076 052 015 plusmn 000 043 plusmn 001 058 333 030 130


(b) Continued


18 431 plusmn 001 531 plusmn 001 962 055 010 plusmn 001 023 plusmn 001 032 198 021 11019 359 plusmn 005 505 plusmn 002 864 058 019 plusmn 001 068 plusmn 000 087 178 026 8020 354 plusmn 004 502 plusmn 002 856 059 015 plusmn 000 047 plusmn 001 062 191 023 9721 350 plusmn 000 531 plusmn 001 881 060 003 plusmn 000 030 plusmn 002 033 082 016 60LK1 1432 plusmn 001 707 plusmn 011 2139 033 076 plusmn 000 052 plusmn 000 128 979 038 301LK2 1560 plusmn 024 769 plusmn 006 2329 033 076 plusmn 000 058 plusmn 004 134 955 049 227LK3 1034 plusmn 004 424 plusmn 004 1458 029 073 plusmn 002 041 plusmn 007 114 551 026 247MH1 760 plusmn 004 582 plusmn 002 1342 043 053 plusmn 000 044 plusmn 006 097 362 023 184MH2 645 plusmn 001 627 plusmn 004 1272 049 046 plusmn 000 042 plusmn 001 087 271 018 176MH3 405 plusmn 006 529 plusmn 004 934 057 031 plusmn 000 034 plusmn 001 065 172 015 134

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem

Labi

le O

M (

)

0

5

10

15

20

25

June-July 2007Dec 2007-Jan 2008

(a)

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Refr

acto

ry O

M (

)

0

5

10

15

20

25

(b)

00

02

04

06

08

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Rp

(c)

Figure 2 Charts with error bars showing the means and standard deviations for (a) labile OM (b) refractory OM and (c) Rp values alongthe downstream mid- and upper Kapuas River the lakes Kapuas Besar (KB) and the Landak and Mempawah Rivers (Mem)


IP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(a)O

P (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(b)

TP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(c)

Figure 3 Charts with error bars showing the means and standard deviations for (a) IP (b) OP and (c) TP along the downstream mid- andupper Kapuas River the lakes Kapuas Besar (KB) and the Landak and Mempawah Rivers (Mem)

The sediment along the stretches of river with the highestpopulation density had the highest IP and OP levels Hencewe concluded that the sedimentary IP and OP originatedfrom human activities and were discharged into the lowerriver via fluvial input Other external sources of P could befrom groundwater fluvial and atmosphere [27] Eutrophica-tion can cause high OM input to sediments which resultsin increased sedimentary TC OC TN TP and OP levels[28] followed by increased decomposition of OM [29] Thissequence of events occurred in the downstreamKapuas Riverwhere the sediment also showed high labile refractory andtotal OM and high OP IP and TP (Figures 2 and 3) Themidriver which is surrounded by oil palm plantations has

higher levels of IP and OP than the upper river but lower Plevels than the lower Kapuas River These results show thathigher levels of P are found near the oil palm plantations thanin the forested area surrounding the upper river but the Plevel was nonetheless lower than in the downstream portionof the river

43 Dynamics of the Kapuas River Forests and tributariesare continuous sources of different amounts of carbon tosurrounding reaches of a river [30] OM is delivered in partic-ulate form such as wood fragments and leaves or sometimesbound to mineral surfaces Factors such as rainfall runoffand snowmelt can affect the supply of organic and inorganic


Distance from river mouth (km)0 200 400 600 800

Rp v

alue

s

030

035

040

045

050

055

060

065

070


(a)


OC

N m

olar

ratio

0

5

10

15

20

25

30

35


(b)

Figure 4 Figure showing the transect profiles of (a) Rp values and (b) TOCTN molar ratios for samples taken during June-July 2007 andDecember 2007-January 2008 All the sampling locations numbered from 1 to 21 in Table 1 and Figure 1 are presented in the graph withlocation 1 situated nearest to the river mouth and location 21 farthest from the river mouth

material to sediment [31] Few studies have determinedthe levels of OM and nutrients along a river system CO

2

emissions and the influx of O2along a river system may be

due to respiration activities fuelled by autochthonous OM[30] thus carbon has been found to outgas during transportfurther downstream [1] Relatively fresh OMwas also amajorsource of atmospheric CO

2emissions because fresh material

has been found to be respired by organisms fairly rapidlythereby contributing to atmospheric CO

2emissions [2] In

a study of fine particulate OM (FPOM) course particulateOM (CPOM) and dissolved OM (DOM) in upstream anddownstream Bolivian tributaries of the Amazon River it wasdetermined that all fractions became more degraded furtherdownstream [32]

In the upper Kapuas River and lakes logging activitiesmay have exposed the forest soil causing elevated aerobicOMdegradationThis degradedmaterial was then dischargedinto the river because of erosion Due to the discharge ofmore degraded OM but less P into the upper river weconcluded that less OMdecomposition occurred in the upperKapuas River The midriver which is surrounded by oil palmplantations hadmedium levels of IP andOP compared to theupper and lower Kapuas River and less degraded OM thanthe upper river This shows that there were higher levels ofP near the oil palm plantations than near the forested areassurrounding the upper river The most densely populatedareas along the Kapuas River were located along the lowerriver A high abundance of fresher sedimentary OM and P inthis location may have resulted in increased phytoplanktonblooms and high rates of OM decomposition The LandakRiver has high levels of labile and refractory OM low Rpvalues and high P levels whereas the Mempawah River haslow levels of labile and refractory OM high Rp values andmedium P levels Hence the Landak River may be moreprone to phytoplankton bloom and OM decomposition than

the Mempawah River Overall June-July 2007 the periodwith higher rainfall than December 2007-January 2008 [17]also showed higher IP OP and TP for most of the locations(Figure 3) indicating some leaching of P from soil into theriver

5 Conclusions

This study is one of few to use the loss-on-ignition experimentto examine sedimentary OM in terms of labile refractoryand total OM and Rp values and to measure P levels inthe sediment along a complete transect of a tropical riverin Southeast Asia This is also one of the few studies tomake further use of the Rp values and CN ratios developedby Kristensen [19] to determine the sources and diagenesisof sedimentary OM The highest P level was located inthe downstream Kapuas River which was the most denselypopulated area The next highest P level was located alongthe midstream river which was surrounded by oil palmplantations The sediment in the upper river which wassurrounded by forest had the lowest P level Phytoplanktonblooms and high OM decomposition most likely occurredalong the downstream Kapuas River where the sediment OMwas fresher and more bioavailable and the P level was thehighest

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

The authors wish to thank everyone for their help and advicethroughout the course of this study This study acknowl-edges the Taiwan National Science Council Research Grants


NSC101-2611-M-110-010-MY3 and MOST103-2611-M-110-010and theAim for the TopUniversity ProgramProject 03C 030204

References

[1] J E Richey J M Melack A K Aufdenkampe V M Ballesterand L L Hess ldquoOutgassing from Amazonian rivers andwetlands as a large tropical source of atmospheric CO

2rdquoNature

vol 416 no 6881 pp 617ndash620 2002[2] E Mayorga A K Aufdenkampe C A Masiello et al ldquoYoung

organic matter as a source of carbon dioxide outgassing fromAmazonian riversrdquo Nature vol 436 no 7050 pp 538ndash5412005

[3] M T H vanVlietWH P Franssen J R Yearsley et al ldquoGlobalriver discharge and water temperature under climate changerdquoGlobal Environmental Change vol 23 no 2 pp 450ndash464 2013

[4] M Floury C Delattre S J Ormerod and Y Souchon ldquoGlobalversus local change effects on a large European riverrdquo Science ofthe Total Environment vol 441 pp 220ndash229 2012

[5] N W Arnell and S N Gosling ldquoThe impacts of climate changeon river flow regimes at the global scalerdquo Journal of Hydrologyvol 486 pp 351ndash364 2013

[6] X X Lu L S Ran S Liu T Jiang S R Zhang and J J WangldquoSediment loads response to climate change a preliminarystudy of eight large Chinese riversrdquo International Journal ofSediment Research vol 28 no 1 pp 1ndash14 2013

[7] D J J Tysmans A J Lohr C Kroeze W P M F Ivens and JVanWijnen ldquoSpatial and temporal variability of nutrient reten-tion in river basins a global inventoryrdquo Ecological Indicatorsvol 34 pp 607ndash615 2013

[8] J P M Syvitski C J Vorosmarty A J Kettner and P GreenldquoImpact of humans on the flux of terrestrial sediment to theglobal coastal oceanrdquo Science vol 308 no 5720 pp 376ndash3802005

[9] S E Page R A J Wust D Weiss J O Rieley W Shotykand S H Limin ldquoA record of Late Pleistocene and Holocenecarbon accumulation and climate change from an equatorialpeat bog (Kalimantan Indonesia) implications for past presentand future carbondynamicsrdquo Journal ofQuaternary Science vol19 no 7 pp 625ndash635 2004

[10] J H M Wosten E Clymans S E Page J O Rieley and SH Limin ldquoPeat-water interrelationships in a tropical peatlandecosystem in Southeast AsiardquoCatena vol 73 no 2 pp 212ndash2242008

[11] M Alkhatib T C Jennerjahn and J Samiaji ldquoBiogeochemistryof the Dumai River estuary Sumatra Indonesia a tropicalblackwater riverrdquo Limnology and Oceanography vol 52 no 6pp 2410ndash2417 2007

[12] A Baum T Rixen and J Samiaji ldquoRelevance of peat drainingrivers in central Sumatra for the riverine input of dissolvedorganic carbon into the oceanrdquo Estuarine Coastal and ShelfScience vol 73 no 3-4 pp 563ndash570 2007

[13] T-H Huang Y-H Fu P-Y Pan and C-T A Chen ldquoFluvialcarbon fluxes in tropical riversrdquo Current Opinion in Environ-mental Sustainability vol 4 no 2 pp 162ndash169 2012

[14] C Freeman C D Evans D T Monteith B Reynolds and NFenner ldquoExport of organic carbon from peat soilsrdquo Nature vol412 no 6849 p 785 2001

[15] L J Tranvik and M Jansson ldquoTerrestrial export of organiccarbonrdquo Nature vol 415 pp 861ndash862 2002

[16] H-K Lui and C-T A Chen ldquoThe nonlinear relationshipbetween nutrient ratios and salinity in estuarine ecosystemsimplications formanagementrdquoCurrent Opinion in Environmen-tal Sustainability vol 4 no 2 pp 227ndash232 2012

[17] P S Loh C-T A Chen G Z Anshari J-TWang J-Y Lou andS-L Wang ldquoA comprehensive survey of lignin geochemistry inthe sedimentary organic matter along the Kapuas River (WestKalimantan Indonesia)rdquo Journal of Asian Earth Sciences vol43 no 1 pp 118ndash129 2012

[18] P S LohC-TAChen J-Y LouG ZAnshariH-YChen andJ-T Wang ldquoComparing lignin-derived phenols 12057513C valuesOCN ratio and 14C age between sediments in the Kaoping(Taiwan) and the Kapuas (Kalimantan Indonesia) RiversrdquoAquatic Geochemistry vol 18 pp 141ndash158 2012

[19] E Kristensen ldquoCharacterization of biogenic organic matter bystepwise thermogravimetry (STG)rdquo Biogeochemistry vol 9 no2 pp 135ndash159 1990

[20] E Kristensen and F Oslash Andersen ldquoDetermination of organiccarbon in marine sediments a comparison of two CHN-analyzer methodsrdquo Journal of Experimental Marine Biology andEcology vol 109 no 1 pp 15ndash23 1987

[21] R A Sutherland ldquoLoss-on-ignition estimates of organic matterand relationships to organic carbon in fluvial bed sedimentsrdquoHydrobiologia vol 389 pp 153ndash167 1998

[22] J D Strickland and T R Parsons A Practical Handbook ofSeawater Analysis Bulletin 167 Fisheries Research Board ofCanada Ottawa Canada 2nd edition 1972

[23] K I Aspila H Agemian and A S Y Chau ldquoA semi-automatedmethod for the determination of inorganic organic and totalphosphate in sedimentsrdquo Analyst vol 101 no 1200 pp 187ndash1971976

[24] F Koroleff Methods of Seawater Analysis Edited by K Grass-hoff Verlag Chemie 1976

[25] G Z Anshari A P Kershaw and S van der Kaars ldquoALate Pleistocene and Holocene pollen and charcoal recordfrom peat swamp forest Lake Sentarum wildlife reserve WestKalimantan Indonesiardquo Palaeogeography PalaeoclimatologyPalaeoecology vol 171 no 3-4 pp 213ndash228 2001

[26] G Anshari A P Kershaw S van der Kaars and G JacobsenldquoEnvironmental change and peatland forest dynamics in theLake Sentarum area West Kalimantan Indonesiardquo Journal ofQuaternary Science vol 19 no 7 pp 637ndash655 2004

[27] S Moore C D Evans S E Page et al ldquoDeep instability ofdeforested tropical peatlands revealed by fluvial organic carbonfluxesrdquo Nature vol 493 no 7434 pp 660ndash663 2013

[28] K Łukawska-Matuszewska J Kiełczewska and J BolałekldquoFactors controlling spatial distributions and relationships ofcarbon nitrogen phosphorus and sulphur in sediments ofthe stratified and eutrophic Gulf of Gdanskrdquo Continental ShelfResearch vol 85 pp 168ndash180 2014

[29] V H Smith G D Tilman and J C Nekola ldquoEutrophicationimpacts of excess nutrient inputs on freshwater marine andterrestrial ecosystemsrdquo Environmental Pollution vol 100 no 1ndash3 pp 179ndash196 1999

[30] J E Richey J I Hedges A H Devol et al ldquoBiogeochemistryof carbon in the Amazon Riverrdquo Limnology and Oceanographyvol 35 no 2 pp 352ndash371 1990


[31] R S Adams and R M Bustin ldquoThe effects of surface areagrain size and mineralogy on organic matter sedimentationand preservation across the modern Squamish Delta BritishColumbia the potential role of sediment surface area in theformation of petroleum source rocksrdquo International Journal ofCoal Geology vol 46 no 2ndash4 pp 93ndash112 2001

[32] J I Hedges E Mayorga E Tsamakis et al ldquoOrganic matter inBolivian tributaries of the Amazon river a comparison to thelower mainstreamrdquo Limnology and Oceanography vol 45 no 7pp 1449ndash1466 2000

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


1 23456

78

9 10

11 1213

1415

16171819

20 21

AB

E

Kapuas River

Mempawah River

Landak River

Kapuas Kecil River

West Kalimantan

CentralKalimantan

East Kalimantan

Sarawak

Lake Sentarum

Lake Pemerak

Lake Pengembung

Kapuas Besar River

SulawesiSumatra

JavaJakarta

Irian Jaya

Malaysia Pacific Ocean

Indian Ocean

SouthChina Sea

Kalimantan

2∘309984000998400998400S

1∘209984000998400998400S

0∘109984000998400998400S

1∘09984000998400998400N

109∘20

9984000998400998400E 110

∘30

9984000998400998400E 111

∘40

9984000998400998400E 112

∘50

9984000998400998400E 114

∘00

9984000998400998400E

Figure 1 Map showing the sampling locations along the Kapuas River (which includes the Kapuas Kecil River and Kapuas Besar River) theMempawah and Landak Rivers and the Lakes Sentarum Pemerak and Pengembung

strategies to maintain the quality of river and estuary watersare more important than ever [4 16] Knowledge of sedimentorganic matter (OM) and nutrients along rivers is beneficialfor developing these management strategies

In this study surface sediments were collected from theKapuas River the Landak River and the Mempawah Riverand from the three lakes that drain into the Kapuas RiverUsing the loss-on-ignition experiment these sediments weretested to determine the labile OM refractory OMand total OM and the Rp values (the ratio of refractoryOM to total OM) Additionally inorganic phosphate (IP)organic phosphate (OP) and total phosphate (TP) levels weredetermined This study presents a profile of OM and P alonga Southeast Asian tropical river for the purpose of furtherunderstanding the dynamics of the river

2 Methods

21 Study Sites The Kapuas River is located in West Kali-mantan Indonesia With a length of 1143 km this is thelongest river in Indonesia and the worldrsquos longest river onan island Sampling was carried out from June to July 2007and December 2007 to January 2008 at the three lakes(Sentarum Pemerak and Pengembung) that drain into theupper Kapuas River at locations spanning the entire extent ofthe Kapuas River and at the Landak and Mempawah RiversDownstream Kapuas River branches into Kapuas Kecil River

and Kapuas Besar River (Figure 1) Sediment was collectedby deploying an Eijkelkamp peat sampler from a small boatinto a water depth of approximately 2m The 0ndash5 cm surfacesediment was saved for chemical analyses In the laboratorythe sediment was dried at 60∘C for a few days groundusing a mortar and pestle and sieved through a 43-meshsieve Details describing the river and sampling locationsincluding the sampling timetable and distances between thelocations and the river mouth are given by Loh et al [17 18]Detailed information on population densities wet and dryseasons and forest types (landscapes) along theKapuas Riverhydrological cycles and sediment loading have been reportedin previous studies [17 18]

22 Analytical Method The loss-on-ignition experiment wascompiled from methods used by Kristensen [19] Kristensenand Andersen [20] and Sutherland [21] A sample of approx-imately 05 g of dried ground and sieved sediment wasweighed in a crucible Crucibles with sediment were weighedand then combusted at 250∘C for 16 hours in a temperature-monitored muffle furnace When cool the crucibles werereweighed The sediment was then heated to 500∘C for 16hours When cool it was weighed again The percentageof weight reduction after reaching 250∘C is known as the labile organic matter The percentage of weight loss thatoccurs within the temperature range between 250∘C and500∘C is the refractory OMThe sum of the labile and





3 Results



4 Discussion












(b) Continued



Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem

Labi

le O

M (

)

0

5

10

15

20

25


(a)

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Refr

acto

ry O

M (

)

0

5

10

15

20

25

(b)

00

02

04

06

08

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Rp

(c)



IP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(a)O

P (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(b)

TP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(c)







Rp v

alue

s

030

035

040

045

050

055

060

065

070


(a)


OC

N m

olar

ratio

0

5

10

15

20

25

30

35


(b)



2





2emissions [2] In




5 Conclusions


Competing Interests


Acknowledgments




References


2rdquoNature











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





3 Results



4 Discussion












(b) Continued



Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem

Labi

le O

M (

)

0

5

10

15

20

25


(a)

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Refr

acto

ry O

M (

)

0

5

10

15

20

25

(b)

00

02

04

06

08

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Rp

(c)



IP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(a)O

P (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(b)

TP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(c)







Rp v

alue

s

030

035

040

045

050

055

060

065

070


(a)


OC

N m

olar

ratio

0

5

10

15

20

25

30

35


(b)



2





2emissions [2] In




5 Conclusions


Competing Interests


Acknowledgments




References


2rdquoNature











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










(b) Continued



Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem

Labi

le O

M (

)

0

5

10

15

20

25


(a)

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Refr

acto

ry O

M (

)

0

5

10

15

20

25

(b)

00

02

04

06

08

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


Rp

(c)



IP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(a)O

P (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(b)

TP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(c)







Rp v

alue

s

030

035

040

045

050

055

060

065

070


(a)


OC

N m

olar

ratio

0

5

10

15

20

25

30

35


(b)



2





2emissions [2] In




5 Conclusions


Competing Interests


Acknowledgments




References


2rdquoNature











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


IP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(a)O

P (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(b)

TP (m

gg)

00

05

10

15

20

Locations

Dow

nstre

am Mid

Upp

er

Lake

s

KB

Land

ak

Mem


(c)







Rp v

alue

s

030

035

040

045

050

055

060

065

070


(a)


OC

N m

olar

ratio

0

5

10

15

20

25

30

35


(b)



2





2emissions [2] In




5 Conclusions


Competing Interests


Acknowledgments




References


2rdquoNature











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



Rp v

alue

s

030

035

040

045

050

055

060

065

070


(a)


OC

N m

olar

ratio

0

5

10

15

20

25

30

35


(b)



2





2emissions [2] In




5 Conclusions


Competing Interests


Acknowledgments




References


2rdquoNature











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



References


2rdquoNature











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of













Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Research Article Sedimentary Organic Matter and Phosphate ...

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Transcript of Research Article Sedimentary Organic Matter and Phosphate ...