Spatial differences in East Scotia ridge hydrothermal vent food webs: influences of chemistry, microbiology and predation on trophodynamics

Reid, W.D.K., Sweeting, C.J., Wigham, B.D., Zwirglmaier, K., Hawkes, J.A., McGill, R.A.R. , Linse, K. and Polunin, N.V.C. (2013) Spatial differences in East Scotia ridge hydrothermal vent food webs: influences of chemistry, microbiology and predation on trophodynamics. PLoS ONE, 8(6), e65553. (doi: 10.1371/journal.pone.0065553) (PMID:23762393) (PMCID:PMC3676328)

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Abstract

The hydrothermal vents on the East Scotia Ridge are the first to be explored in the Antarctic and are dominated by large peltospiroid gastropods, stalked barnacles (Vulcanolepas sp.) and anomuran crabs (Kiwa sp.) but their food webs are unknown. Vent fluid and macroconsumer samples were collected at three vent sites (E2, E9N and E9S) at distances of tens of metres to hundreds of kilometres apart with contrasting vent fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. δ13C of dissolved inorganic carbon from vent fluids ranged from −4.6‰ to 0.8‰ at E2 and from −4.4‰ to 1.5‰ at E9. The lowest macroconsumer δ13C was observed in peltospiroid gastropods (−30.0‰ to −31.1‰) and indicated carbon fixation via the Calvin-Benson-Bassham (CBB) cycle by endosymbiotic gamma-Proteobacteria. Highest δ13C occurred in Kiwa sp. (−19.0‰ to −10.5‰), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. δ13C differed among sites, which were attributed to spatial differences in the epibiont community and the relative contribution of carbon fixed via the reductive tricarboxylic acid (rTCA) and CBB cycles assimilated by Kiwa sp. Site differences in carbon fixation pathways were traced into higher trophic levels e.g. a stichasterid asteroid that predates on Kiwa sp. Sponges and anemones at the periphery of E2 assimilated a proportion of epipelagic photosynthetic primary production but this was not observed at E9N. Differences in the δ13C and δ34S values of vent macroconsumers between E2 and E9 sites suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB) entering the hydrothermal vent food webs vary between the sites.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McGill, Dr Rona
Authors: Reid, W.D.K., Sweeting, C.J., Wigham, B.D., Zwirglmaier, K., Hawkes, J.A., McGill, R.A.R., Linse, K., and Polunin, N.V.C.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in PLoS ONE 8(6):e65553
Publisher Policy:Reproduced under a Creative Commons License

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