Agneta Andersson

My research deals with, among other things, the effects of increased inflow of organic matter on marine food webs, predation-resistant bacteria and how they are affected by nutrient conditions in the marine environment and eutrophication linked to environmental toxins.

The research focuses on phytoplankton and bacteria, which constitute basic resources in marine pelagic food webs. It is mainly these organisms that produce particulate organic carbon from dissolved inorganic and organic carbon. Phytoplankton and bacteria have different sizes, which means that bacteria-based food webs have more trophic levels than phytoplankton-based food webs. They also have a diverse chemical stoichiometry and molecular composition, indicating that they are of different food quality for higher trophic levels.

Global climate change has been predicted to cause increased rainfall in northern Europe. This will cause increased river runoff of allochthonous dissolved organic carbon and other nutrients to the coastal areas of the ocean. As the light climate deteriorates, phytoplankton production may decrease while bacterial production increases. Production will be based more on allochthonous coal than on autochthonous coal.

My research group investigates how such a shift in the base resource can affect the production of organisms at higher trophic levels. It is possible that the amount of fish produced per unit of production will be lower due to greater respiratory losses and poorer food quality. This can be of great importance for the structure and functioning of the marine ecosystem. The question is investigated through a combination of empirical experiments and modelling. The project provides understanding and prediction of biodiversity changes in the ocean.

Strategic research program EcoChange

Marine science at Umeå University

Research group Marine Ecology