Search

Members of the bacterial genus Sulfurimonas (phylum Campylobacterota) dominate microbial communities in marine redoxclines and are important for sulfur and nitrogen cycling. Here we used metagenomics and metabolic analyses to characterize a Sulfurimonas from the Gakkel Ridge in the Central Arctic Ocean and Southwest Indian Ridge, showing that this species is ubiquitous in non-buoyant hydrothermal plumes at Mid Ocean Ridges across the global ocean. One Sulfurimonas species, USulfurimonas pluma, was found to be globally abundant and active in cold (Sulfurimonas species, US. pluma has a reduced genome (>17%) and genomic signatures of an aerobic chemolithotrophic metabolism using hydrogen as an energy source, including acquisition of A2-type oxidase and loss of nitrate and nitrite reductases. The dominance and unique niche of US. pluma in hydrothermal plumes suggest an unappreciated biogeochemical role for Sulfurimonas in the deep ocean.

Members of the genus Sulfurimonas (phylum Campylobacterota) dominate microbial communities of benthic and pelagic redox clines, playing a key role in the biogeochemistry of these environments. Investigating neutrally buoyant hydrothermal plumes of the Central Arctic Ocean, we found a novel type of Sulfurimonas that inhabits hydrogen-rich and oxygen-saturated environments close to the freezing point. Using omics’ approaches, we compared the diversity and distribution of Sulfurimonas from Gakkel Ridge hydrothermal plumes with those from different Mid Ocean Ridges and other Sulfurimonas-hosting environments. A single and new Sulfurimonas species, USulfurimonas pluma, was found to be globally abundant and active in cold (US. pluma features substantial genome reduction and specific genomic traits (e.g., oxygen detoxification mechanisms, acquisition of A2-type oxidase, loss of nitrate and nitrite reductases) compared to other Sulfurimonas species. These traits are indicative for adaptation to an obligate aerobic chemolithotrophic life style in hydrogen-rich plumes, US. pluma dominates microbial communities of metal-rich neutrally-buoyant hydrothermal plumes, suggesting a so far neglected roles of Sulfurimonas in ocean biogeochemistry and food webs.

Oxygen reduction in a cable bacterium is condensed in a few terminal cells, while the rest of the filament lives oxygen free., The electric wires of cable bacteria possibly support a unique respiration mode with a few oxygen-reducing cells flaring off electrons, while oxidation of the electron donor and the associated energy conservation and growth is allocated to other cells not exposed to oxygen. Cable bacteria are centimeter-long, multicellular, filamentous Desulfobulbaceae that transport electrons across oxic-anoxic interfaces in aquatic sediments. From observed distortions of the oxic-anoxic interface, we derived oxygen consumption rates of individual cable bacteria and found biomass-specific rates of unheard magnitude in biology. Tightly controlled behavior, possibly involving intercellular electrical signaling, was found to generally keep 90% of the cells metabolize in the convenient absence of oxidative stress.