Organic Biogeochemistry in West Mata, NE Lau Hydrothermal Vent Fields

The impact of submarine hydrothermal systems on organic carbon in the ocean—one largest fixed reservoirs Earth—could be profound. Yet, different vent sites show diverse fluid chemical compositions and subsequent biological responses. Observations from various are to evaluate systems' ocean cycle. A response cruise May 2009 an on-going eruption at West Mata Volcano, northeast Lau Basin, provided opportunity quantify matter production a back-arc spreading system. Hydrothermal fluids contained elevated dissolved carbon, particulate (POC), nitrogen (PN) relative background seawater. δ13C-POC values for suspended particles diffuse (−15.5‰ −12.3‰) distinct those seawater (−23 ± 1‰), indicative unique synthesis pathways microbes counterparts. first concentrations reported vents were similar or higher than Enhanced fixation denitrification removed 37%–89% total recharging flow paths. plume samples enriched POC PN, indicating enhanced production. “dark” within matches thermodynamic prediction based available reducing substances supplied plume. This research combines measured contents with modeled results demonstrates importance activities water column deep ocean.