Open AccessD esulfofrigus sp. prevails in sulfate‐reducing dilution cultures from sediments of the B enguela upwelling area
Author(s) -
Kraft Beate,
Engelen Bert,
Goldhammer Tobias,
Lin YuShih,
Cypionka Heribert,
Könneke Martin
Publication year - 2013
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/1574-6941.12039
Subject(s) - upwelling , biogeochemical cycle , sediment , biology , sulfate , sulfate reducing bacteria , environmental chemistry , chemosynthesis , oceanography , dilution , ecology , microbial population biology , geology , bacteria , chemistry , paleontology , hydrothermal vent , physics , organic chemistry , hydrothermal circulation , thermodynamics
Sediments of coastal upwelling areas are generally characterized by a high content of organic carbon that is mainly degraded via anaerobic microbial processes including sulfate reduction as a major terminal oxidation step. Despite the high importance of sulfate reduction in these sediments, the identity of sulfate‐reducing bacteria ( SRB ) has remained almost unknown. Here, we applied a cultivation‐based approach using selective enrichment conditions to study the diversity and distribution of active SRB in sediments along a transect perpendicular to the continental slope off the coast of N amibia (Meteor‐cruise M76/1). To promote growth of the most abundant SRB , dilution series were prepared and amended with hydrogen, acetate, or a mixture of monomers representing typical substrates for SRB . Growth of SRB could be detected in the presence of all electron donors and from sediment down to 4 m depth. 16 S r RNA gene‐based DGGE analysis and sequencing revealed the predominance of SRB related to psychrophiles in particular to the genus D esulfofrigus , which made up 1 % of the total microbial community, accounting for an absolute abundance of up to 4.8 × 10 7 cells mL −1 . In general, the abundance of cultured SRB changed with depth and between the different sampling sites and correlated with the content of organic carbon as previously reported. Growth of chemolithotrophic SRB in relatively high dilution steps and the enrichment of methanogens as well as acetogens from deeper sediment point to a competition between hydrogen‐utilizing microbial processes and their biogeochemical significance in deep sediment layers of the B enguela upwelling area.