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Toxicology Centre
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Tse, T. J., Doig, L. E., Quiñones-Rivera, Z., Leavitt, P. R., Codling, G., Lucas, B. T. Liber, K., Giesy, J. P., Wheater, H., and Jones, P. D
A paleolimnological investigation of phytoplankton trends in a narrow river-valley reservoir
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Introduction Narrow-river dammed reservoirs possess longitudinal gradients
• 3 zones: riverine, transitional and lacustrine (Thornton et al., 1990)
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Introduction Up-reservoir
• Narrow basin, high flow, low light • Increased allochthonous input (terrestrial)
Mid-reservoir • Broader and deeper basin, reduced flow, increased light due to
decreased turbidity • Decreased advective nutrient supply
Down-reservoir • Broad, deep basin (lacustrine), slow flow, clear water, increased light • Increased autochthonous input (phytoplankton)
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Introduction
Fossil pigments can be preserved in sediments for thousand of years if preserved under optimal conditions (e.g. low light, low temperature, low dissolved oxygen).
Can provide insight into mapping historic and recent populations of the phototrophic community and estimate productivity.
Many pigments are shared among taxa, some are unambiguous markers
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Toxicology Centre
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Case Site – Lake Diefenbaker, SK Multipurpose reservoir opened in
1967
Provides water for 45% of Saskatchewan residences (Government of Saskatchewan)
Characteristically similar to narrow-river dammed reservoirs
Trophic status: mesotrophic
Predominant cyanobacterial species determined to be Anabaena circinalis (Hecker et al., 2012).
Anabaena circinalis (Source: http://web.mst.edu/~microbio/BIO221_2010/A_circinalis.html)
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Sample Sites
• Samples were collected from mid-channel locations, over a longitudinal gradient
QC
ON
MB SK AB
Site 2 Site 1
Site 3
Site 4
Site 7
Site 8
Site 6
Site 5
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Materials and Methods Sediment cores: sectioned
at 1-cm intervals under a constant stream of N2
Pigments extraction and
HPLC analysis completed (Leavitt and Hodgson 2001)
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Results:
Site 1 (Up-reservoir)
Site 2 (Up-reservoir)
Fucoxanthin
Concentration (nmol pigment g OC-1)
0 25 50
Sedim
ent d
epth
(cm)
0
5
10
15
20
25
30
Lutein -
zeaxanthin
0 50 100
Canthaxanthin
0 15 30
Chlorophyll a
0 50 100
Echinenone
0 3 6
Total cyano-pigments
0 50 100
Total phytopigments
0 250 500
Fucoxanthin
Concentration (nmol pigment g OC-1)
0 20 40
Sedim
ent d
epth
(cm)
0
10
20
30
40
50
Lutein -
zeaxanthin
0 40 80
Canthaxanthin
0 15 30
Chlorophyll a
0 50 100
Echinenone
0 2 4
Total cyano-pigments
0 50 100
Total phytopigments
0 200 400
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Results:
Site 3 (Mid-reservoir)
Site 4 (Mid-reservoir)
Fucoxanthin
Concentration (nmol pigment g OC-1)
0 125 250Se
dimen
t dep
th (cm
)
0
10
20
30
40
50
Lutein -
zeaxanthin
0 50 100
Canthaxanthin
0 30 60
Chlorophyll a
0 500 1000
Echinenone
0 10 20
Total cyano-pigments
0 100 200
Total phytopigments
0 800 1600
Fucoxanthin
Concentration (nmol pigment g OC-1)
0 100 200
Sedim
ent d
epth
(cm)
0
10
20
30
40
50
Lutein -
zeaxanthin
0 50 100
Canthaxanthin
0 20 40
Chlorophyll a
0 900 1800
Echinenone
0 15 30
Total cyano-pigments
0 70 140
Total phytopigments
0 1500 3000
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Sample Sites
QC
ON
MB SK AB
Site 2 Site 1
Site 3
Site 4
Site 7
Site 8
Site 6
Site 5
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Results:
Site 5 (Down-reservoir)
Site 6 (Down-reservoir)
Lutein -
zeaxa
nthin
0 50 100
Canthaxanthin
0 25 50
Chlorophyll a
0 900 1800
Echinenone
0 15 30
Total cyano-pigments
0 70 140
Total phyto
pigments
0 1200 2400
Year
1971
1981
1991
2001
2011
Fucoxa
nthin
Concentration (nmol pigment g OC-1)
0 150 300
Sedim
ent d
epth
(cm
)
0
5
10
15
Lutein -
zeaxa
nthin
0 50 100
Canthaxanthin
0 25 50
Chlorophyll a
0 600 1200
Echinenone
0 10 20
Total cyano-pigments
0 80 160
Total phyto
pigments
0 1200 2400
Year
1971
1981
1991
2001
2011
Fucoxa
nthin
Concentration (nmol pigment g OC-1)
0 125 250
Sedim
ent d
epth
(cm
)
0
10
20
30
40
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Results:
Site 7 (Gardiner arm)
Site 8 (Qu’Appelle arm)
Fucox
anthi
n
Concentration (nmol pigment g OC-1)
0 75 150
Sed
imen
t dep
th (c
m)
0
5
10
15
20
25
Lutei
n -
zeax
anthi
n
0 100 200
Cantha
xanth
in
0 40 80
Chlorop
hyll a
0 450 900
Echine
none
0 20
Myxox
antho
phyll
0 20 40
Total c
yano
-pigm
ents
0 150 300
Total p
hytop
igmen
ts
0 900 1800
Year
1971
1981
1991
2001
2011
Year
1971
1981
1991
2001
2011
Fucox
anthi
n
Concentration (nmol pigment g OC-1)
0 80 160
Sed
imen
t dep
th (c
m)
0
4
8
12
Lutei
n -
zeax
anthi
n
0 30 60
Cantha
xanth
in
0 20 40
Chlorop
hyll a
0 250 500
Echine
none
0 5 10
Myxox
antho
phyll
0 5 10
Total c
yano
-pigm
ents
0 45 90
Total p
hytop
igmen
ts
0 500 1000
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Results – Spatial variation (top 1-cm segment)
Distance (km)
0 20 40 60 80 100 120 140
Con
cent
ratio
n (n
mol
pig
men
t g O
C-1
)
0
500
1000
1500
2000
2500
Chlorophyll aTotal pigment
Distance (km)
0 20 40 60 80 100 120 140
Con
cent
ratio
n (n
mol
pig
men
t g O
C-1
)
0
20
40
60
80
100
120
140Chlorophyll a and total pigments Total cyano-pigments
More allochthonous input
More autochthonous input
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Distance (km)
0 20 40 60 80 100 120 140
Con
cent
ratio
n (n
mol
pig
men
t g O
C-1
)
0
200
400
600
800
1000
1200Chlorophyll aTotal pigment
Distance (km)
0 20 40 60 80 100 120 140
Con
cent
ratio
n (n
mol
pig
men
t g O
C-1
)
0
40
60
80
100
Results – Spatial variation (mean pigment concentrations)
Chlorophyll a and total pigments Total cyano-pigments
More allochthonous input
More autochthonous input
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Discussion – Spatial Gradient Pigment concentrations increased longitudinally with distance
down-reservoir (decreased turbidity and increased light penetration).
Lowest pigment concentrations occurring at locations furthest up-reservoir (increased turbidity and light limitations).
Bulk of material carried into the reservoir are deposited prior to site 3, with a gradual decrease in deposition rate until site 6 (Johansson et al., 2014).
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Discussion – Temporal Gradient Three phases of reservoir development:
• Trophic upsurge • Depression in productivity • Gradual increase or decrease in biological productivity
• Despite these expectations, comparison of pigment profiles among sites provides little evidence of marked trophic surge following inundation of the South Saskatchewan River Valley.
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Acknowledgements Committee Members:
• Dr. Paul Jones (Supervisor) • Dr. Lorne Doig (Co-supervisor) • Dr. Markus Hecker • Dr. Lynn Weber • Dr. Jeff Sereda • Dr. Tim Jardine
• Postdoctoral Fellow: • Dr. Garry Codling
• Lab Helpers:
• Allison Hill • Brett Lucas
• University of Regina:
• Dr. Peter Leavitt • Dr. Zoraida Quiñones-Rivera
Funding provided by: • Global institute for Water Security (GIWS)
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