Publication Date:
2021-03-29
Description:
Due to its extreme salinity and high Mg concentration the Dead Sea is characterized by a very low density of cells most of
which are Archaea. We discovered several underwater fresh to brackish water springs in the Dead Sea harboring dense
microbial communities. We provide the first characterization of these communities, discuss their possible origin,
hydrochemical environment, energetic resources and the putative biogeochemical pathways they are mediating.
Pyrosequencing of the 16S rRNA gene and community fingerprinting methods showed that the spring community
originates from the Dead Sea sediments and not from the aquifer. Furthermore, it suggested that there is a dense Archaeal
community in the shoreline pore water of the lake. Sequences of bacterial sulfate reducers, nitrifiers iron oxidizers and iron
reducers were identified as well. Analysis of white and green biofilms suggested that sulfide oxidation through
chemolitotrophy and phototrophy is highly significant. Hyperspectral analysis showed a tight association between
abundant green sulfur bacteria and cyanobacteria in the green biofilms. Together, our findings show that the Dead Sea floor
harbors diverse microbial communities, part of which is not known from other hypersaline environments. Analysis of the
water’s chemistry shows evidence of microbial activity along the path and suggests that the springs supply nitrogen,
phosphorus and organic matter to the microbial communities in the Dead Sea. The underwater springs are a newly
recognized water source for the Dead Sea. Their input of microorganisms and nutrients needs to be considered in the
assessment of possible impact of dilution events of the lake surface waters, such as those that will occur in the future due to
the intended establishment of the Red Sea - Dead Sea water conduit.
Keywords:
Dead Sea; Archaeal community
;
551
Language:
English
Type:
article
,
publishedVersion
Format:
21
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