The biological pollutant pump: how a phytoplankton
bloom alters the concentrations of organic chemicals
in the marine environment
Gert
1
Everaert ,
Frederik De
2
Laender ,
Peter L.M.
1
Goethals ,
Colin R.
1
Janssen
1Laboratory
of Environmental Toxicology and Aquatic Ecology (GhEnToxLab), Ghent University, Ghent, Belgium
2 Research Unit in Environmental and Evolutionary Biology, Université de Namur, Namur, Belgium
Introduction
• Empirical evidence of the role of the
biological pollutant pump is often
based on small spatial and temporal
scales
• The marine environment is a sink for
many chemical substances
• The biological pump is the biologically
driven
(e.g.
phytoplankton)
sequestration of carbon from the
atmosphere to the deep sea
• Research question
 Do multidecadal field data
support the biological pollutant
pump theory?
(1)
Materials & Methods
Apply regression-based statistics on existing data and compare the inferred trends
Study area
Monitoring data
Statistics
Coupling
North Sea
Data via ICES repository
(www.ices.dk)
Regression-based analysis
for each variable
Correlation analysis
1
2
3
4
Concentration
Concentrations:
(1) Chlorophyll a
440 records (1975 – 2012)
(2) Sediment organic carbon
136 records (1990 – 2012)
(3) PCB concentrations
1,139 records (1994 – 2012)
~ f(
)
+ f(
)
Are these concentrations
correlated?
(1) Chlorophyll a
(2) Sediment organic carbon
(3) PCBs
Results & Discussion
Sediment organic carbon
-0.50
2
4
6
8
10
0.00
-0.50
-1.00
2
12
4
6
8
0.00
-0.15
-0.30
-1.0
-2.0
2
4
8
10
0.20
0.00
-0.20
-0.40
12
2
4
6
6
trends
10
8
10
12
8
10
1.50
1.00
0.50
0.00
-0.50
2
12
4
are
6
Time (Month)
Time (Month)
seasonal
8
Time (Month)
• Boxplots & regression-based analyses: seasonal
variations found in chlorophyll a, sediment
organic carbon and PCB concentrations in
sediment
analysis:
0.0
12
0.40
Time (Month)
• Correlation
coupled
10
Estimated smooth of month
Estimated smooth of month
0.15
6
1.0
Time (Month)
0.30
4
2.0
-3.0
Time (Month)
2
(log10 µg/kg dry weight)
0.00
0.50
PCB concentration
0.50
Sediment PCB
3.0
(log10 g/100g dry weight)
Organic carbon content
(log10 mg/L)
Chlorophyll a concentration
1.00
Estimated smooth of month
Regressionbased analysis
Data exploration
Chlorophyll a
12
(2)
Correlation analysis
[PCB]sediment
[PCB]sediment
[CHFLa]water
-
[CHFLa]water
0.57 (0.004)
[OC]sediment
0.80 (<0.001)
0.56 (0.004)
(2)
Conclusion
Large-scale spatio-temporal coupling between seasonal dynamics of phytoplankton, sediment organic
carbon and PCB concentrations was observed and supported the biological pollutant pump theory
1Herndl
et al., Nat. Geosci. 2013, 6, 718-724; 2 Everaert et al., Environ. Sci. Technol. 2015, 49, 8704-8711
Gert Everaert is supported by a post-doctoral fellowship from the Special Research Fund of Ghent University (BOF15/PDO/061)
VLIZ YMSD poster No. 21 - Gert.Everaert@UGent.be – www.ecotox.ugent.be