title: Ecology and biogeography of megafauna and macrofauna at the first known deep-sea hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge.
abstract: The Southwest Indian Ridge is the longest section of very slow to ultraslow-spreading seafloor in the global mid-ocean ridge system, but the biogeography and ecology of its hydrothermal vent fauna are previously unknown. We collected 21 macro- and megafaunal taxa during the first Remotely Operated Vehicle dives to the Longqi vent field at 37° 47'S 49° 39'E, depth 2800 m. Six species are not yet known from other vents, while six other species are known from the Central Indian Ridge, and morphological and molecular analyses show that two further polychaete species are shared with vents beyond the Indian Ocean. Multivariate analysis of vent fauna across three oceans places Longqi in an Indian Ocean province of vent biogeography. Faunal zonation with increasing distance from vents is dominated by the gastropods Chrysomallon squamiferum and Gigantopelta aegis, mussel Bathymodiolus marisindicus, and Neolepas sp. stalked barnacle. Other taxa occur at lower abundance, in some cases contrasting with abundances at other vent fields, and δ13C and δ15N isotope values of species analysed from Longqi are similar to those of shared or related species elsewhere. This study provides baseline ecological observations prior to mineral exploration activities licensed at Longqi by the United Nations.
authors.affiliation: Ocean &Earth Science, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: J T
authors.initials: JT
authors.lastname: Copley
authors.affiliation: Ocean &Earth Science, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: L
authors.initials: L
authors.lastname: Marsh
authors.affiliation: Life Sciences Department, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors.forename: A G
authors.initials: AG
authors.lastname: Glover
authors.affiliation: National Oceanography Centre, European Way, Southampton SO14 3ZH, UK.
authors.forename: V
authors.initials: V
authors.lastname: Hühnerbach
authors.affiliation: Ocean &Earth Science, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: V E
authors.initials: VE
authors.lastname: Nye
authors.affiliation: School of Biology, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK.
authors.forename: W D K
authors.initials: WD
authors.lastname: Reid
authors.affiliation: Dove Marine Laboratory, School of Marine Science &Technology, Newcastle University, Cullercoats NE30 4PZ, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Sweeting
authors.affiliation: Dove Marine Laboratory, School of Marine Science &Technology, Newcastle University, Cullercoats NE30 4PZ, UK.
authors.forename: B D
authors.initials: BD
authors.lastname: Wigham
authors.affiliation: Life Sciences Department, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors.forename: H
authors.initials: H
authors.lastname: Wiklund
mesh_terms: D000818:Animals; D044822:Biodiversity; D049872:Bivalvia / Q000145:classification / Q000254:growth & development*; D049851:Gastropoda / Q000145:classification / Q000254:growth & development*; D060086:Hydrothermal Vents / Q000032:analysis*; D019156:Indian Ocean; D010802:Phylogeny; D058974:Phylogeography; D011077:Polychaeta / Q000145:classification / Q000254:growth & development*; D058998:Remote Sensing Technology; D012623:Seawater; D001468:Thoracica / Q000145:classification / Q000254:growth & development*