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North Atlantic octocorals: Distribution, Ecology and Phylogenetics

North Atlantic octocorals: Distribution, Ecology and Phylogenetics
North Atlantic octocorals: Distribution, Ecology and Phylogenetics
Most studies of deep-sea benthic fauna have concentrated on soft sediments with little sampling in rocky areas and even less on non-vent mid-ocean ridges and within submarine canyons, mainly as a result of difficulty accessing them. To assess the distribution and abundance of cold-water corals along an Axial Volcanic Ridges along the Mid-Atlantic ridge at 45oN 27oW, and within the Whittard Canyon along the Irish Margin video footage from the ROV Isis taken during a three scientific cruises was analysed. Samples were also taken to allow taxonomic and phylogentic work to be completed. Abundance of octocorals per 100 m transect were calculated and mapped using Arc GIS, with a maximum of 59 in the AVR compared to 855 within the Whittard Canyon. Thirty-one putative species were identified within the Whittard Canyon including some scleractinians, Eleven more than were found in along the AVR. Both locations indicated differences in coral assemblages dependent on substratum type with sedimented areas having increased occurrence of Pennatulidae and Chrysogorgiidae within the AVR and an increased abundance of Acanella and Radicipes upon sediment in comparison to rock within the Whittard Canyon. It is suggested that these differences in abundance and assemblage structure, both within and between the AVR and Whittard Canyon sites, reflects higher food availability as well as differences in substratum type on which coral larvae settle.
Taxononomic investigations identified 4 new species from samples taken along the AVR, and are described within the thesis. Phylogenetic analysis of novel sequences obtained throughout this study, as well as published sequences, showed the presence of 3 clades A) Calcaxonia and some Alcyoniidae B) Holoaxonia and Pennatulacea C) some Alcyoniidae, Corallium and Paragorgia. When individual MSH1 and ND2 genes were combined the Pennatulacea separated out as a fourth clade. This was attributed to an increase in resolution when two or more genes are used for analysis. Results indicate that morphological taxonomy and molecular analysis are not in agreement and there is a requirement for some taxonomic revisions using molecular data to confirm species boundaries and help guide taxonomic decisions.
Morris, Kirsty Janet
c770a780-d6e0-4b8d-a163-cf3f45188967
Morris, Kirsty Janet
c770a780-d6e0-4b8d-a163-cf3f45188967
Tyler, Paul
d1965388-38cc-4c1d-9217-d59dba4dd7f8
Rogers, Alex
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Morris, Kirsty Janet (2011) North Atlantic octocorals: Distribution, Ecology and Phylogenetics. University of Southampton, School of Ocean and Earth Science, Doctoral Thesis, 299pp.

Record type: Thesis (Doctoral)

Abstract

Most studies of deep-sea benthic fauna have concentrated on soft sediments with little sampling in rocky areas and even less on non-vent mid-ocean ridges and within submarine canyons, mainly as a result of difficulty accessing them. To assess the distribution and abundance of cold-water corals along an Axial Volcanic Ridges along the Mid-Atlantic ridge at 45oN 27oW, and within the Whittard Canyon along the Irish Margin video footage from the ROV Isis taken during a three scientific cruises was analysed. Samples were also taken to allow taxonomic and phylogentic work to be completed. Abundance of octocorals per 100 m transect were calculated and mapped using Arc GIS, with a maximum of 59 in the AVR compared to 855 within the Whittard Canyon. Thirty-one putative species were identified within the Whittard Canyon including some scleractinians, Eleven more than were found in along the AVR. Both locations indicated differences in coral assemblages dependent on substratum type with sedimented areas having increased occurrence of Pennatulidae and Chrysogorgiidae within the AVR and an increased abundance of Acanella and Radicipes upon sediment in comparison to rock within the Whittard Canyon. It is suggested that these differences in abundance and assemblage structure, both within and between the AVR and Whittard Canyon sites, reflects higher food availability as well as differences in substratum type on which coral larvae settle.
Taxononomic investigations identified 4 new species from samples taken along the AVR, and are described within the thesis. Phylogenetic analysis of novel sequences obtained throughout this study, as well as published sequences, showed the presence of 3 clades A) Calcaxonia and some Alcyoniidae B) Holoaxonia and Pennatulacea C) some Alcyoniidae, Corallium and Paragorgia. When individual MSH1 and ND2 genes were combined the Pennatulacea separated out as a fourth clade. This was attributed to an increase in resolution when two or more genes are used for analysis. Results indicate that morphological taxonomy and molecular analysis are not in agreement and there is a requirement for some taxonomic revisions using molecular data to confirm species boundaries and help guide taxonomic decisions.

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More information

Published date: October 2011
Organisations: University of Southampton, Ocean and Earth Science, Ocean Biochemistry & Ecosystems

Identifiers

Local EPrints ID: 338892
URI: https://eprints.soton.ac.uk/id/eprint/338892
PURE UUID: c09147f3-fc0a-41a3-ad78-3d4286d0c41f

Catalogue record

Date deposited: 17 May 2012 10:44
Last modified: 18 Jul 2017 05:56

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