Microdistribution of Faunal Assemblages at Deep-Sea Hydrothermal Vents in the Southern Ocean


Marsh, Leigh, Copley, Jonathan T., Huvenne, Veerle A.I., Linse, Katrin, Reid, William D.K., Rogers, Alex D., Sweeting, Christopher J. and Tyler, Paul A. (2012) Microdistribution of Faunal Assemblages at Deep-Sea Hydrothermal Vents in the Southern Ocean. PLoS ONE, 7, (10), e48348. (doi:10.1371/journal.pone.0048348).

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Description/Abstract

Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and hydrothermal activity in a vent field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of hydrothermal activity, and a mosaic image of >250 m2 of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from vent sources and peak temperatures. Assemblages closest to vent sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m−2), followed by a peltospiroid gastropod (>1,500 individuals m−2), eolepadid barnacle (>1,500 individuals m−2), and carnivorous actinostolid anemone (>30 individuals m−2). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for vent fauna in this new biogeographic province. An increase in δ34S values of primary consumers with distance from vent sources, and variation in their δ13C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent environment over a greater extent than previous studies, these results provide a baseline for determining temporal change and investigations of processes structuring faunal assemblages at Southern Ocean vents.

Item Type: Article
ISSNs: 1932-6203 (print)
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Q Science > QE Geology
Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Natural and Environmental Sciences > Ocean and Earth Science > Ocean Biochemistry & Ecosystems
National Oceanography Centre (NERC) > Marine Geoscience
ePrint ID: 344880
Date Deposited: 05 Nov 2012 11:54
Last Modified: 28 Mar 2014 15:22
Research Funder: NERC
Projects:
Chemosynthetically-driven ecosystems south of the Polar Front: biogeography and ecology
Funded by: NERC (NE/D01249X/1)
Led by: Paul Tyler
16 June 2008 to 15 July 2014
URI: http://eprints.soton.ac.uk/id/eprint/344880

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