The University of Southampton
University of Southampton Institutional Repository

Macrofaunal abundance and community composition at lower bathyal depths in different branches of the Whittard Canyon and on the adjacent slope (3500 m; NE Atlantic)

Macrofaunal abundance and community composition at lower bathyal depths in different branches of the Whittard Canyon and on the adjacent slope (3500 m; NE Atlantic)
Macrofaunal abundance and community composition at lower bathyal depths in different branches of the Whittard Canyon and on the adjacent slope (3500 m; NE Atlantic)
We studied benthic macrofaunal abundance and community composition in replicate Megacorer samples obtained from three sites in different branches of the Whittard Canyon (NE Atlantic) and one site on the adjacent slope to the west of the canyon system. All sites were located at a depth of ~3500 m. Abundance (macrobenthos sensu stricto, >300 ?m) varied significantly (p<0.001) among sites, and decreased from east to west; highest in the Eastern branch (6249±standard deviation 1363 ind. m?2) and lowest on the slope (2744±SD 269 ind. m?2). Polychaetes were the dominant taxon, making up 53% of the macrofauna, followed by isopods (11%), tanaids (10%), bivalves (7%) and sipunculans (7%). Among the polychaetes, the Amphinomidae was the dominant family (27%), followed by the Spionidae (22%). Assemblage composition changed across the sites. From east to west, the proportion of polychaetes and isopods decreased (by 6% in each case), while sipunculans and tanaids increased (by 13% and 8%, respectively). The ranking of the two dominant polychaete families reversed from east to west (Eastern branch—Amphinomidae 36%, Spionidae 21%; Slope—Spionidae 30%, Amphinomidae 10%). Ordination of faunal groups (macrofaunal higher taxa, and polychaete families) revealed that the Central and Eastern branches were substantially similar, while the Western branch and slope sites were relatively distinct. A very similar pattern was evident in a corresponding ordination of environmental variables across the sites. An analysis of faunal similarities (ANOSIM) indicated that the Western branch/slope and Central branch/Eastern branch groups displayed the highest similarity. The clearest separation was between the slope and the Eastern branch. We conclude that, when compared at the same water depth, macrofaunal abundance and composition varies between open slope and canyon location, as well as among canyon branches. These differences probably reflect the influence of organic enrichment together with hydrodynamic activity, both of which are influenced by the topographic profile of individual canyon branches.
Whittard Canyon, Submarine canyons, Deep sea, Macrobenthos, Polychaetes
0967-0637
29-39
Gunton, Laetitia
8a51e73d-fb9f-429a-aad7-880ae75e0b7d
Gooday, Andrew
d9331d67-d518-4cfb-baed-9df3333b05b9
Glover, Adrian
577928b1-4bb5-418c-ab84-2b85a011a1e1
Bett, Brian
61342990-13be-45ae-9f5c-9540114335d9
Gunton, Laetitia
8a51e73d-fb9f-429a-aad7-880ae75e0b7d
Gooday, Andrew
d9331d67-d518-4cfb-baed-9df3333b05b9
Glover, Adrian
577928b1-4bb5-418c-ab84-2b85a011a1e1
Bett, Brian
61342990-13be-45ae-9f5c-9540114335d9

Gunton, Laetitia, Gooday, Andrew, Glover, Adrian and Bett, Brian (2015) Macrofaunal abundance and community composition at lower bathyal depths in different branches of the Whittard Canyon and on the adjacent slope (3500 m; NE Atlantic). Deep Sea Research Part I: Oceanographic Research Papers, 97, 29-39. (doi:10.1016/j.dsr.2014.11.010).

Record type: Article

Abstract

We studied benthic macrofaunal abundance and community composition in replicate Megacorer samples obtained from three sites in different branches of the Whittard Canyon (NE Atlantic) and one site on the adjacent slope to the west of the canyon system. All sites were located at a depth of ~3500 m. Abundance (macrobenthos sensu stricto, >300 ?m) varied significantly (p<0.001) among sites, and decreased from east to west; highest in the Eastern branch (6249±standard deviation 1363 ind. m?2) and lowest on the slope (2744±SD 269 ind. m?2). Polychaetes were the dominant taxon, making up 53% of the macrofauna, followed by isopods (11%), tanaids (10%), bivalves (7%) and sipunculans (7%). Among the polychaetes, the Amphinomidae was the dominant family (27%), followed by the Spionidae (22%). Assemblage composition changed across the sites. From east to west, the proportion of polychaetes and isopods decreased (by 6% in each case), while sipunculans and tanaids increased (by 13% and 8%, respectively). The ranking of the two dominant polychaete families reversed from east to west (Eastern branch—Amphinomidae 36%, Spionidae 21%; Slope—Spionidae 30%, Amphinomidae 10%). Ordination of faunal groups (macrofaunal higher taxa, and polychaete families) revealed that the Central and Eastern branches were substantially similar, while the Western branch and slope sites were relatively distinct. A very similar pattern was evident in a corresponding ordination of environmental variables across the sites. An analysis of faunal similarities (ANOSIM) indicated that the Western branch/slope and Central branch/Eastern branch groups displayed the highest similarity. The clearest separation was between the slope and the Eastern branch. We conclude that, when compared at the same water depth, macrofaunal abundance and composition varies between open slope and canyon location, as well as among canyon branches. These differences probably reflect the influence of organic enrichment together with hydrodynamic activity, both of which are influenced by the topographic profile of individual canyon branches.

Text
1-s2.0-S0967063714002143-main.pdf - Version of Record
Available under License Other.
Download (1MB)

More information

Accepted/In Press date: December 2014
Published date: March 2015
Keywords: Whittard Canyon, Submarine canyons, Deep sea, Macrobenthos, Polychaetes
Organisations: Ocean and Earth Science, Marine Biogeochemistry

Identifiers

Local EPrints ID: 372727
URI: http://eprints.soton.ac.uk/id/eprint/372727
ISSN: 0967-0637
PURE UUID: 8b8b6285-f617-47d9-9d57-97bacc29bade

Catalogue record

Date deposited: 15 Dec 2014 14:01
Last modified: 27 Apr 2022 12:10

Export record

Altmetrics

Contributors

Author: Laetitia Gunton
Author: Andrew Gooday
Author: Adrian Glover
Author: Brian Bett

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×