Research project Climate change causes increased precipitation in boreal areas, which in turn leads to elevated inflows of coloured dissolved organic matter to the coast. How will this affect the productivity in the sea?
The changes may lead to decreased phytoplankton production, while the heterotrophic microbial production will increase. In the northernmost basin of the Baltic Sea, the Bothnian Bay, the dissolved organic carbon concentration has increased and the fatty acid quality of herring decreased over the past 25 years, which might be due to rewiring of the food web towards microbes of poor fatty acid quality. We will analyse amino acid stable isotopes (AA-SI) composition in herring muscle to elucidate if the food web channelling has changed over the past 25 years in the Gulf of Bothnia.
Tharindu Bandara Herath, SLU Uppsala
Danny Lau, SLU Uppsala
The AA-SI signature is modified at each trophic transfer in the food web. While some specific amino acids keep the same isotopic composition, others are enriched in heavy isotopes at each trophic level, allowing to discriminate the number of trophic steps to the top of the food web. We will test if 1) the food web energy channelling in the Bothnian Bay has changed during the past 25 years and 2) if the food web to a greater extent will be directed via the microbial pathway in the Bothnian Bay than in the Bothnian Sea.
