School of Geography & Water@Leeds, University of Leeds, LS2 9JT, UK
Abstract. Sedimented hydrothermal vents are those in which hydrothermal fluid vents through sediment and are among the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermally active and off-vent areas of the Bransfield Strait (1050–1647 m depth). Microbial composition, biomass and fatty acid signatures varied widely between and within vent and non-vent sites and provided evidence of diverse metabolic activity. Several species showed diverse feeding strategies and occupied different trophic positions in vent and non-vent areas and stable isotope values of consumers were generally not consistent with feeding structure morphology. Niche area and the diversity of microbial fatty acids reflected trends in species diversity and was lowest at the most hydrothermally active site. Faunal utilisation of chemosynthetic activity was relatively limited but was detected at both vent and non-vent sites as evidenced by carbon and sulphur isotopic signatures, suggesting that the hydrothermal activity can affect trophodynamics over a much wider area than previously thought.
How to cite. Bell, J. B., Reid, W. D. K., Pearce, D. A., Glover, A. G., Sweeting, C. J., Newton, J., and Woulds, C.: Hydrothermal activity lowers trophic diversity in Antarctic sedimented hydrothermal vents, Biogeosciences Discuss. [preprint], https://doi.org/10.5194/bg-2016-318, 2016.
Received: 27 Jul 2016 – Discussion started: 31 Aug 2016
Areas of the deep-seafloor where hydrothermal fluid flows through sediment are amongst the least studied environments on the planet. We studied the faunal and microbial food webs at one such system in the Southern Ocean and found evidence of a wide range of organic matter fixation pathways, both at vent sites and non-vent sites. Although faunal uptake of in situ food production was low, it was much wider spread than previously realised, raising important questions about seafloor food webs.
Areas of the deep-seafloor where hydrothermal fluid flows through sediment are amongst the least...