The distribution of organic pollutants in the sea will be influenced by climate change, according to a researcher at Sweden's Umeå University.

Matyas Ripszam found that climate change models for the Nordic region predict an increase in freshwater runoff into the Baltic Sea, resulting in greater inflow of terrestrial dissolved organic carbon. This, in turn, will have a major impact on the organic pollutants in the northern Baltic Sea, since the carbon can interact with the pollutants and decrease their concentration in the water, he said.

"This doesn't mean that the organic pollutants become less of a threat. A higher organic carbon load might lead to the development of ecosystems where micro-organisms mainly feed on dissolved organic carbon, thus opening a way for the pollutants to enter the food web and cause more problems in higher level organisms, like fish," Ripszam pointed out.

As part of his study, Ripszam developed a method to measure the extent to which contaminants partition to dissolved organic carbon.

He also examined the effects of higher temperature and different concentration of organic carbon content on the distribution of pollutants in modelled real-life marine ecosystems. Results showed that higher temperature alone led to increased losses of pollutants, while higher organic carbon content retained more pollutants in the model ecosystems.

However, the combined effect of both parameters showed no real patterns. This was because some pollutants were more sensitive to changes in temperature and others to increased organic carbon content, Ripszam explained.