Sampling Site
N
Mariager Fjord
Hobro
Mariager
Kattegat
Graphic from http:\\nm.aaa.dk\mfjord
Inner fjord salinity:
12-17‰ at top
18-24‰ at bottom
Outer fjord salinity:
20-25‰
Mariager Catchment
Area: 572 km2
66% agriculture
17% woodland
9% towns
8% lakes
Graphic from http:\\nm.aaa.dk\mfjord1\3 water from catchment
Mariager Fjord - Land Reclamation
Stratification in the inner fjord - when sampling March 2002
2002
Salinity
Oxygen
2002
Graphics from http:\\nm.aaa.dk\mfjord
Oxygen Conditions Now
Depth
Oxygen & Hydrogen Sulphide
Oxygen
Hydrogen Sulphide
Graphic from http:\\nm.aaa.dk\mfjord
Oxygen in 1997
Graphic from http:\\nm.aaa.dk\mfjord
Oxygen in 1997
Graphic from http:\\nm.aaa.dk\mfjord
MOLTEN cores in Mariager Fjord
Two sampling occasions
September 2001 - MF1-5: possibly over-cored
March 2003 - MF6 - 9: intact surface
MF8 - Master Core - dated
Visual assessment showed no major changes down core - all black & smelly
High water content, all levels > 90%
Core CorrelationMF6
R2 = 0,9999
y = -3,2459x + 2005,3
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
0 5 10 15 20 25 30 35
MF8, 210Pb-dated MF6 & MF9 diatom correlated
M F2
0
10
20
30
40
0 20 40 60 80
Depth (cm)
LO
I (%
of
dry
we
igh
t)
Sediment Properties
LOI high (15-30%)
Increase at 20cm
M F9
6,0
6,5
7,0
7,5
8,0
8,5
9,0
9,5
0 10 20 30 40
Depth (cm)
Me
an
pa
rtic
le s
ize
(m
)
No major change in particle size
05
10
15
20
25
0 20 40 60 80 100
BS
i (w
t%)
0,0
0,5
1,0
1,5
2,0
0 20 40 60 80 100
TN
(w
t%)
05
10
15
20
25
0 20 40 60 80 100
TC
(w
t%)
Geochemistry - MF2
TN (1-2%), TC (6-15%) & BSi (10-23%) are all high for coastal sediments
The changes towards core top will disappear when fluxed/corrected for salt concentration
TN
TC
BSi
Pigments - MF6
Comparison between the sitesChlorophyll a Carotenoids
• Mariager Fjord has a very high concentration of pigmentscompared to the other long-core sites
Mariager Fjord, Denmark
0 1000 2000
De
pth
(cm
)
0
10
20
30
0 1000 0 500 1000 15000 500 1000
nmol/gTC
0 500 10000 500 0 500 0 5000 5000 500
210Pb dating
2000
1990
1980
1970
1950
1925
• No shift in community composition, diatoms and dinoflagellates show species change 1890-1925
• Steady increase in chlorophyll a and carotenoids over time
• Dominating pigments in good agreement with monitored algae (diatoms, dinoflagellates) and the ciliate Mesodinium rubrum
• Good preservation, low chl a degradation/chl a ratio
2000
1966
1901
1937
MF9 dominant
0
10
20
30
40
50
60
70
80
90
0 10 20 30 40 cm
%
Polykrikos schwartzii
Lingulodiniumpolyedrum
Cysts from 9 taxa found in core MF9
1985 1950 1915
1930
Dinoflagellates
1890
Dinoflagellates
MF9 5-35 %
0
10
20
30
40
50
60
70
0 10 20 30 40cm
%Protoceratiumreticulatum
Spiniferites total.
Protoperidiniumconicum
Finpigget brun (incllyse)
1985 1950 1915 1890
1920
0
5
10
15
20
25
30
35
40
0 0,2 0,4 0,6 0,8 1
cm
pr. cyst
Total brown acritarch1890
1915
1950
1985
1925
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
0 20
ChaRes
0 20 40
ChaVeg
0 20 40 60 80
SkeCos
0 20 40 60 80
CycCho
0 20 40 60
Tha1A
0 20
DitBri
0 20
FraEllA
G
0 20
OpeM
ut
0
PlanDelG
0,0 1,5 3,0 4,5 6,0 7,5
B:P
1890
2001
1920
1965
Diatoms
Excluded taxa & Benthic:Planktonicexcluded
Diatoms
Main Taxa and Reconstructions
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
0
Planot
hidiu
m d
elica
tulum
agg
.
0
Opeph
ora
hors
tiana
0
Opeph
ora
minu
ta
0 20
Opeph
ora
mut
abilis
0
Thalas
siosir
a pr
osch
kinae
0
Tabula
ria fa
scicu
lata
agg.
0 20 40 60
Thalas
siosir
a sp
. 1A
0 20
Thalas
siosir
a cf.
min
ima
0
Cocco
neis
scut
ellum
0 20 40 60 80
Cyclot
ella
choc
tawha
tche
eana
0
Cyclot
ella
men
eghin
iana
0 20
Fragil
aria
ellip
tica
agg.
0
Navicu
la pe
rmin
uta
0 20
Nitzsc
hia cf
. am
erica
na
0
Paulie
lla ta
eniat
a
0 20
Thalas
siosir
a cf.
guil
lardii
0
Thalas
siosir
a wei
ssflo
gii
2.7 3.0 3.3 3.6 3.9
Diatom
-infe
rred
TN
60 100 140 180 220 260
TP
Stable Isotopes - MF9Mariager Delta N15 vs Depth
0
5
10
15
20
25
30
35
0 2 4 6 8 10 12 14
Delta N15
De
pth
(C
m)
1910
1955
1920
1997
1990
High values No distinct shifts Several possible explanations
Increased fertiliser? Periodic anoxia - more denitrification?
%N in MF9
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
1 2 3 4 7 8 9 10 12 14 16 18 20 24 28 32
Depth
% N
%N from Stable Isotope Analysis
1910
1997
2000
1990
Decrease in %N at core top - denitrification leading to N release as N2 gas? Or will it disappear when fluxed/corrected?
N Fertilizer applied to Mariager Catchment
1935 1955 1975 1995
More fertilizer would lead to heavier N isotopes
1000 tons N/year
Lag?Graphic from http:\\nm.aaa.dk\mfjord
Mariager Delta 13C vs Depth
0
5
10
15
20
25
30
35
40
-23.5 -23 -22.5 -22 -21.5 -21
Delta 13C
De
pth
(c
m)
1890
1920
1975
1993
2000
Fossil fuel burning correction needed - would accentuate increaseProductivity proxy? Increase in anoxic events?
%C
0
2
4
6
8
10
12
14
1 2 3 4 7 8 9 10 12 14 16 18 20 24 28 32 37
Depth
%C
%C from Stable Isotope Analysis
1890
1920
2000
1993
1975
1997
%C decreases at core top - disappear when fluxed/corrected?
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
11 august1987
07 maj 1990 31 januar 1993 28 oktober1995
24 juli 1998 19 april 2001 14 januar 2004
Mariager Areal Productivity
No obvious change
Summation
• Little change seen in TN, TC & BSi
• Good pigment preservation, general agreement with monitoring data, but no indication of community shift
• Largest changes in dinoflagellate species between 1890-1930
• Large change in diatom B:P 1890-1920 Transfer functions hampered by lack of analogues in top, little
agreement between models and no agreement with monitored data
• Delta 15N may show fertilizer signal. Delta 13C signal may reflect increase in anoxia
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