Active microbial communities facilitate carbon turnover in brine pools found in the deep Southeastern Mediterranean Sea.
Mar Environ Res
; 198: 106497, 2024 Jun.
Article
in En
| MEDLINE
| ID: mdl-38631226
ABSTRACT
Discharge of gas-rich brines fuels productive chemosynthetic ecosystems in the deep sea. In these salty, methanic and sulfidic brines, microbial communities adapt to specific niches along the physicochemical gradients. However, the molecular mechanisms that underpin these adaptations are not fully known. Using metagenomics, we investigated the dense (â¼106 cell ml-1) microbial communities that occupy small deep-sea brine pools found in the Southeastern Mediterranean Sea (1150 m water depth, â¼22 °C, â¼60 PSU salinity, sulfide, methane, ammonia reaching millimolar levels, and oxygen usually depleted), reaching high productivity rates of 685 µg C L-1 d-1 ex-situ. We curated 266 metagenome-assembled genomes of bacteria and archaea from the several pools and adjacent sediment-water interface, highlighting the dominance of a single Sulfurimonas, which likely fuels its autotrophy using sulfide oxidation or inorganic sulfur disproportionation. This lineage may be dominant in its niche due to genome streamlining, limiting its metabolic repertoire, particularly by using a single variant of sulfide quinone oxidoreductase. These primary producers co-exist with ANME-2c archaea that catalyze the anaerobic oxidation of methane. Other lineages can degrade the necromass aerobically (Halomonas and Alcanivorax), or anaerobically through fermentation of macromolecules (e.g., Caldatribacteriota, Bipolaricaulia, Chloroflexota, etc). These low-abundance organisms likely support the autotrophs, providing energy-rich H2, and vital organics such as vitamin B12.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Seawater
/
Bacteria
/
Archaea
/
Microbiota
Language:
En
Journal:
Mar Environ Res
/
Mar. environ. res
/
Marine environmental research
Journal subject:
BIOLOGIA
/
SAUDE AMBIENTAL
/
TOXICOLOGIA
Year:
2024
Document type:
Article
Country of publication:
United kingdom