Bacterial community responses to dissolved organic matter shifts in the coastal northern Baltic Sea

Bacteria are major consumers of dissolved organic matter (DOM) in aquatic systems. In coastal zones, bacteria are exposed to a variety of different types of DOM originating from land and the open sea. Climate change is expected to cause increased inflows of freshwater to the northern coastal zones, which may lead either to eutrophication or to increased inputs of refractive terrestrial compounds. How bacterial communities respond compositionally and functionally to such changes are poorly known. We performed a 2-day microcosm experiment in two bays in the coastal northern Baltic Sea, where effects of plankton derived DOM (AtDOM, mimicking eutrophication) and terrestrial organic matter (tDOM) were studied.