Relative contribution of persistent organic pollutants to marine phytoplankton biomass dynamics in the North Sea and the Kattegat

In a recent research paper published in Chemosphere, Gert Everaert and co-workers quantified the relative contribution of persistent organic pollutants to marine phytoplankton biomass dynamics. To do so, they used concentrations of persistent organic pollutants (POPs) to infer potential POP-induced effects on marine primary production in the Kattegat and the North Sea. They modelled phytoplankton dynamics using four classical drivers (light and nutrient availability, temperature and zooplankton grazing) and tested whether extending this model with a POP-induced phytoplankton growth limitation term improved predictions of the observed chlorophyll a concentrations. They found that including monitored concentrations of PCBs and pesticides did not lead to a better model fit, suggesting that the influence of POP-induced growth limitation of marine phytoplankton in the North Sea and the Kattegat on primary production is small compared to that caused by the classical drivers. The authors also calculated the potential impact of 2 hypothetical scenarios: 10 and 100 times the monitored concentrations of PCBs and pesticides with. Under these two configurations, region-specific contributions of POPs in the phytoplankton growth limitation were found. The inferred contribution of POPs to phytoplankton growth limitation was ca. 1% in Belgian marine waters, but in the Kattegat POPs explained ca. 10% of the phytoplankton growth limitation.

 

Scientific abstract

In this paper, we use concentrations of persistent organic pollutants (POPs) and of chlorophyll a to infer POP-induced effects on marine primary production in the Kattegat and the North Sea between the 1990s and the 2000s. To do so, we modelled phytoplankton dynamics using four classical drivers (light and nutrient availability, temperature and zooplankton grazing) and tested whether extending this model with a POP-induced phytoplankton growth limitation term improved model fit to observed chlorophyll a concentrations. Including monitored concentrations of PCBs and pesticides did not lead to a better model fit, suggesting that POP-induced growth limitation of marine phytoplankton in the North Sea and the Kattegat is small compared to the limitations caused by the classical drivers. In an attempt to more fully represent the multitude of POPs in the marine environment, the monitored concentrations were multiplied with a factor 10 and 100. Under these two configurations, region-specific contributions of POPs in the phytoplankton growth limitation were found. The inferred contribution of POPs to phytoplankton growth limitation was ca. 1% in Belgian marine waters, but in the Kattegat POPs explained ca. 10% of the phytoplankton growth limitation. These results suggest that there are regional differences in the contribution of POPs to the phytoplankton growth limitation



Full reference (link):

Everaert G, De Laender F, Goethals PLM, Janssen CR. 2015. Relative contribution of persistent organic pollutants to marine phytoplankton biomass dynamics in the North Sea and the Kattegat. Chemosphere 134: 76-83.

 

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