Benthic Bacterial Community Composition in the Oligohaline-Marine Transition of Surface Sediments in the Baltic Sea Based on rRNA Analysis
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Kuupäev
2018
Kättesaadav alates
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Frontiers
Abstrakt
Salinity has a strong impact on bacterial community composition such that freshwater
bacterial communities are very different from those in seawater. By contrast, little is
known about the composition and diversity of the bacterial community in the sediments
(bacteriobenthos) at the freshwater-seawater transition (mesohaline conditions). In this
study, partial 16S-rRNA sequences were used to investigate the bacterial community
at five stations, representing almost freshwater (oligohaline) to marine conditions, in the
Baltic Sea. Samples were obtained from the silty, top-layer (0–2.5 cm) sediments with
mostly oxygenated conditions. The long water residence time characteristic of the Baltic
Sea, was predicted to enable the development of autochthonous bacteriobenthos at
mesohaline conditions. Our results showed that, similar to the water column, salinity is
a major factor in structuring the bacteriobenthos and that there is no loss of bacterial
richness at intermediate salinities. The bacterial communities of marine, mesohaline,
and oligohaline sediments differed in terms of the relative rRNA abundances of the
major bacterial phyla/classes. At mesohaline conditions typical marine and oligohaline
operational taxonomic units (OTUs) were abundant. Putative unique OTUs in mesohaline
sediments were present only at low abundances, suggesting that the mesohaline
environment consists mainly of marine and oligohaline bacteria with a broad salinity
tolerance. Our study provides a first overview of the diversity patterns and composition
of bacteria in the sediments along the Baltic Sea salinity gradient as well as new insights
into the bacteriobenthos at mesohaline conditions.
The study was funded by the Leibniz Institute for Baltic Sea Research (IOW), KJ were funded by the DFG project MicroFun (JU367/15-1), JK by the Leibniz Association project TemBi (SAW-2011-IGB-2).
The study was funded by the Leibniz Institute for Baltic Sea Research (IOW), KJ were funded by the DFG project MicroFun (JU367/15-1), JK by the Leibniz Association project TemBi (SAW-2011-IGB-2).
Kirjeldus
Märksõnad
brackish microbiology, estuarine ecology, Baltic Sea, bacteriobenthos, bacterial diversity and community composition, articles