Paul C, Reunamo A, Lindehoff E, Bergkvist J, Mausz MA, Larsson H, Richter H, Wängberg SA, Leskinen P, Bamstedt U, Pohnert G
mesocosm, plankton interactions, aldehydes, oxylipins, Umea, Sweden, indoor, 2 m3
Several marine and freshwater diatoms produce polyunsaturated aldehydes(PUA) in wound-activated processes. These metabolites are also released by intact diatomcells during algal blooms. Due to their activity in laboratory experiments, PUA areconsidered as potential mediators of diatom-bacteria interactions. Here, we tested thehypothesis that PUA mediate such processes in a close-to-field mesocosm experiment.Natural plankton communities enriched with Skeletonema marinoi strains that differ intheir PUA production, a plankton control, and a plankton control supplemented with PUAat natural and elevated concentrations were observed. We monitored bacterial and viralabundance as well as bacterial community composition and did not observe any influenceof PUA on these parameters even at elevated concentrations. We rather detected analternation of the bacterial diversity over time and differences between the two S. marinoistrains, indicating unique dynamic bacterial communities in these algal blooms. Theseresults suggest that factors other than PUA are of significance for interactions betweendiatoms and bacteria.