Microbial mats and physicochemistry in a saltern in the Bretagne (France) and in a laboratory scale saltern model |
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Authors: | Dieter Giani Jacob Seeler Luise Giani Wolfgang E Krumbein |
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Institution: | Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, F.R.G.;Soil Science Division, University of Oldenburg, Oldenburg, F.R.G.;Biological Science Center, Boston University, Boston, MA, U.S.A. |
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Abstract: | Abstract A saltern near La Baule (Bretagne, France) was remodeled in a programmable temperature and humidity controlled walk-in environmental chamber resembling the characteristics of the original saltern. The saltern showed different types of microbial mats predominantly composed of algae, oxy- and anoxyphotobacteria, and associated chemoorganotrophic bacteria, fungi and animals. Well-developed microbial mats were found up to a salinity of 10% during the three or four months in summer when salinity gradients and NaCl precipitation were established. The main phototrophic organisms were diatoms, the cyanobacteria Aphanothece, Microcoleus, Spirulina , and Oscillatoria , and Chromatiaceae. At higher salinity, Halobacterium sp., diatoms, and Dunaliella were dominant. Typical microbial mats and saltern-typical invertebrate, algal and bacterial species also developed in the saltern model, building up a stable community. The ionic composition of the brines and physicochemical parameters were similar to those determined for the original saltern. Different photosynthetic organisms, e.g. a filamentous purple bacterium and a hypersaline Chloroflexus -like organism, could be enriched within the microbial mats by changing the light regime. |
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Keywords: | Microbial communities Sediment composition Ionic composition Gypsum precipitation Influence of light Chloroflexus |
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