Microbial and chemical characterization of underwater fresh water springs in the Dead Sea.
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.
Max Planck Institute for Marine Microbiology, Bremen, Germany. dionescu@mpi-bremen.de
Danny
D
Ionescu
Christian
C
Siebert
Lubos
L
Polerecky
Yaniv Y
YY
Munwes
Christian
C
Lott
Stefan
S
Häusler
Mina
M
Bižić-Ionescu
Christian
C
Quast
Jörg
J
Peplies
Frank Oliver
FO
Glöckner
Alban
A
Ramette
Tino
T
Rödiger
Thorsten
T
Dittmar
Aharon
A
Oren
Stefan
S
Geyer
Hans-Joachim
HJ
Stärk
Martin
M
Sauter
Tobias
T
Licha
Jonathan B
JB
Laronne
Dirk
D
de Beer
D001105:Archaea / Q000235:genetics / Q000302:isolation & purification; D018441:Biofilms / Q000254:growth & development; D019414:Chlorobi / Q000235:genetics / Q000302:isolation & purification; D000458:Cyanobacteria / Q000235:genetics / Q000302:isolation & purification; D005618:Fresh Water / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D014871:Water Microbiology
D012336:RNA, Ribosomal, 16S