Phototrophic Bacteria in the Plußsee: Ecology of the Sulfuretum

Abstract

A eutrophic lake like the Plußsee is divided into the aerobic epilimnion, the metalimnion as defined by the thermocline, and the anaerobic hypolimnion. In the upper zone of the hypolimnion phototrophic sulfur bacteria are temporarily abundant if there is a supply of light and H2S. They are represented by the families Chromatiaceae (purple sulfur bacteria) and Chlorobiaceae (green sulfur bacteria). Their ability to oxidize reduced sulfur compounds without oxygen consumption is ecologically very important for the lake metabolism. In contrast to the phototrophic sulfur bacteria, the Rhodospirillaceae (purple nonsulfur bacteria) rarely occur in spectacular mass accumulations. In the dark part of the hypolimnion, moreover, a great variety of different colorless anaerobic bacteria are present; among them are sulfate reducers, which depend on a supply of substrate from phototrophic bacteria.KeywordsHydrogen SulfidePhototrophic BacteriumPurple Sulfur BacteriumMeromictic LakeReduce Sulfur CompoundThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.