Abstract
Microbes are integral components of aquatic food webs and are crucial for the cycling of carbon and nutrients. Microbial populations are controlled by a combination of abiotic (e.g. nutrients, temperature) and biotic (e.g. grazing by flagellates) factors. Learning about the control of individual populations in the natural environment is crucial for e.g. preventing blooms of harmful algae or predicting occurrence of pathogens, but is also challenging since interactions may be complex. In this project we will use a food web approach to dissect the control of individual microbial populations in the Baltic Sea. We will determine the community composition of bacterioplankton and small protists (grazers) in a large number of samples, and measure how populations of bacterioplankton and protists co-vary, both over time and over spatial scales (from Skagerrak to the Bay of Bothnia). An interaction network will be constructed based on patterns of co-variation among populations and between populations and environmental variables. This will reveal the most significant positive (e.g. symbiotic) as well as negative (e.g. grazing) interactions. The accuracy of the approach will be evaluated in detail on pathogenic Vibrio populations.
Sweden