Articles | Volume 14, issue 24
Biogeosciences, 14, 5705–5725, 2017
Biogeosciences, 14, 5705–5725, 2017

Research article 20 Dec 2017

Research article | 20 Dec 2017

Hydrothermal activity lowers trophic diversity in Antarctic hydrothermal sediments

James B. Bell1,2,3, William D. K. Reid4, David A. Pearce5, Adrian G. Glover2, Christopher J. Sweeting4, Jason Newton6, and Clare Woulds1 James B. Bell et al.
  • 1School of Geography & Water at Leeds, University of Leeds, LS2 9JT, UK
  • 2Life Sciences Dept., Natural History Museum, Cromwell Rd, London SW7 5BD, UK
  • 3Centre for Environment, Fisheries and Aquaculture Science, Lowestoft NR34 0HT, UK
  • 4Marine Sciences-School of Natural and Environmental Sciences, Ridley Building, Newcastle University, NE1 7RU, UK
  • 5Applied Sciences, Northumbria University, Newcastle NE1 8ST, UK
  • 6NERC Life Sciences Mass Spectrometry Facility, SUERC, East Kilbride G75 0QF, UK

Abstract. Hydrothermal sediments are those in which hydrothermal fluid is discharged through sediments and are one of the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermal and background areas of the Bransfield Strait (1050–1647 m of depth). Microbial composition, biomass, and fatty acid signatures varied widely between and within hydrothermally active and background sites, providing evidence of diverse metabolic activity. Several species had different feeding strategies and trophic positions between hydrothermally active and inactive areas, and the stable isotope values of consumers were not consistent with feeding morphology. Niche area and the diversity of microbial fatty acids was lowest at the most hydrothermally active site, reflecting trends in species diversity. Faunal uptake of chemosynthetically produced organics was relatively limited but was detected at both hydrothermal and non-hydrothermal sites, potentially suggesting that hydrothermal activity can affect trophodynamics over a much wider area than previously thought.

Short summary
Sedimented hydrothermal vents are among the least studied deep-sea ecosystems. We compared food webs between hydrothermally active and off-vent areas of the Bransfield Strait, Antarctica. Invertebrates showed diverse feeding strategies and occupied different positions in food webs between vent and non-vent sites. Feeding and microbial diversity was lowest at vent sites. Chemosynthetic organic matter was a minimal food source at both vents and non-vents.
Final-revised paper