Short Communication Phylogenetic Characterization of Phosphatase-Expressing Bacterial Communities in Baltic Sea Sediments

Phosphate release from sediments hampers the remediation of aquatic systems from a eutrophic state. Microbial phosphatases in sediments release phosphorus during organic matter degradation. Despite the important role of phosphatase-expressing bacteria, the identity of these bacteria in sediments is largely unknown. We herein presented a culture-independent method to phylogenetically characterize phosphatase-expressing bacteria in sediments. We labeled whole-cell extracts of Baltic Sea sediments with an artificial phosphatase substrate and sorted phosphatase-expressing cells with a flow cytometer. Their phylogenetic affiliation was determined by Denaturing Gradient Gel Electrophoresis. The phosphatase-expressing bacterial community coarsely reflected the whole-cell bacterial community, with a similar dominance of Alphaproteobacteria. Key words: phosphatase; phosphorus biogeochemistry, eutrophication, flow cytometer, ELF labeling Benthic phosphorus (P) fluxes are an important factor that determines the availability of P for primary producers in the water layer. Whether P is released or retained in sediments is largely controlled by the activity of benthic prokaryotes (6). Therefore, a full understanding of benthic P cycling is needed in order to mitigate the hypoxic conditions caused by anthro-pogenic influences in many aquatic systems