Since the peak years in the 1970’s and 1980’s, emissions of chemicals to the Baltic Sea have generally emerged from well-defined point sources emitting few chemicals in high amounts, to many small diffuse sources, emitting a large number of chemicals. The identity of many of the chemicals emitted to the Baltic Sea are not known, neither their risk to ecosystem structure and functions. An inherent deficit of current risk assessments is that they are performed on single chemicals, thereby excluding all the unknowns and the complex environmental chemical mixtures as well as effects on ecosystem functions. 

In this study, sediment from a reference site in the Baltic Sea in the Askö area will be sampled. Experiments will be performed in sediment microcosms, with added chemicals at increasing chemical activity to investigate responses to chemical pollution.

Structural response variables to be measured include benthic community structure with particular emphasis on often neglected meiofauna community and bacteria that will be assessed by high throughput marker gene analysis of environmental DNA and RNA. The study will also assess functional responses by measuring rates of ecosystem processes related to nitrogen cycling in Baltic sediments, as sediment denitrification and DNRA rates, both quantified through the 15N-nitrate method. Oxidative biomarkers are particularly relevant as predictors of higher biological organization because of the link between oxidative processes and life-history traits.

Researchers and departments:
Anna Sobek, Department of Environmental Science and Analytical Chemistry (ACES)
Francisco Nascimento, Department of Ecology, Environment and Plant Sciences (DEEP)
Agnes Karlsson, ACES and DEEP