Gene expression profiling of microbial activities and interactions in sediments under haloclines of E. Mediterranean deep hypersaline anoxic basins.
Deep-sea hypersaline anoxic basins (DHABs) in the Eastern Mediterranean Sea are considered some of the most polyextreme habitats on Earth. In comparison to microbial activities occurring within the haloclines and brines of these unusual water column habitats near the Mediterranean seafloor, relatively little is known about microbial metabolic activities in the underlying sediments. In addition, it is not known whether activities are shaped by the unique chemistries of the different DHAB brines and whether evidence exists for active microbial eukaryotes in those sediments. Metatranscriptome analysis was applied to sediment samples collected using ROV Jason from underneath the haloclines of Urania, Discovery and L'Atalante DHABs and a control site. We report on expression of genes associated with sulfur and nitrogen cycling, putative osmolyte biosynthetic pathways and ion transporters, trace metal detoxification, selected eukaryotic activities (particularly of fungi), microbe-microbe interactions, and motility in sediments underlying the haloclines of three DHABs. Relative to our control sediment sample collected outside of Urania Basin, microbial communities (including eukaryotes) in the Urania and Discovery DHAB sediments showed upregulation of expressed genes associated with nitrogen transformations, osmolyte biosynthesis, heavy metals resistance and metabolism, eukaryotic organelle functions, and cell-cell interactions. Sediments underlying DHAB haloclines that have cumulative physico-chemical stressors within the limits of tolerance for microoorganisms can therefore be hotspots of activity in the deep Mediterranean Sea.
Department of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Virginia P
VP
Edgcomb
Department of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Maria G
MG
Pachiadaki
Department of Chemistry, University of Crete, Heraklion, Greece.
Paraskevi
P
Mara
Department of Ichthyology & Aquatic Environment, University of Thessaly, Volos, Greece.
Konstantinos A
KA
Kormas
Department of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Edward R
ER
Leadbetter
Department of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Joan M
JM
Bernhard
D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D017753:Ecosystem; D020869:Gene Expression Profiling; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D008522:Mediterranean Sea; D012623:Seawater / Q000737:chemistry / Q000382:microbiology; D012965:Sodium Chloride / Q000032:analysis / Q000378:metabolism
D001426:Bacterial Proteins; D012965:Sodium Chloride