MEPS 128:161-170 (1995)  -  doi:10.3354/meps128161

Mats of colourless sulphur bacteria. I. Major microbial processes

Fenchel T, Bernard C

Mats of colourless sulphur bacteria from 2 marine sediments were studied with respect to sulphide and oxygen fluxes, rates of key microbial processes and spatial and temporal heterogeneity. In a relatively protected habitat dominated by Beggiatoa species, about 70% of the sediment O2-consumption could be accounted for by the oxidation of S2- to SO42-, about 15% by food chains fuelled by chemoautotrophic production, while the remainder was due to aerobic processes not directly associated with the sulphur cycle. In this sediment about 85% of the allochthonous and autochthonous (phototrophic and chemotrophic production) organic carbon was mineralised anaerobically. The other habitat was a shallow bay which is often subject to wave-induced transport and erosion of the sediment. From autumn to spring, sediment surface communities of colourless sulphur bacteria were patchy in time and space and they represented different successional stages with respect to the composition of the biota and to process rates. Here the relative significance of chemoautotrophic sulphide oxidation was highly variable. During summer the surface microbial communities of this sediment were dominated by phototrophs and the colourless sulphur bacteria constituted a less important component.


Microbial mats . Chemoautotrophic production . Colourless sulphur bacteria . Oxic-anoxic interphase


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