The University of Southampton
University of Southampton Institutional Repository

Cold-water coral mounds in an erosive environmental setting: TOBI side-scan sonar data and ROV video footage from the northwest Porcupine Bank, NE Atlantic

Cold-water coral mounds in an erosive environmental setting: TOBI side-scan sonar data and ROV video footage from the northwest Porcupine Bank, NE Atlantic
Cold-water coral mounds in an erosive environmental setting: TOBI side-scan sonar data and ROV video footage from the northwest Porcupine Bank, NE Atlantic
Cold-water coral mounds are common features in certain regions along the Atlantic margin. They occur in mound provinces in various settings, characterised by specific environmental conditions that steer and influence coral mound initiation, growth and demise (e.g. bottom current intensity, sediment input and food supply). In order to add detail to the diversity of environmental conditions described in relation to these structures, this study investigates mounds in a generally erosive setting on the northwest Porcupine Bank (NE Atlantic)—in contrast to previous studies in less hydrodynamically active settings.
TOBI (Towed Ocean Bottom Instrument) side-scan sonar data revealed abundant erosive features in the study area. They occur in the form of erosional scarps, erosional pits and locally scoured seabed. Furthermore, two large (several hundred metres high) and 101 small (tens of metres high) cold-water coral mounds were identified on the TOBI images. Most of the mounds are located on top of erosional scarps pointing to the cold-water corals' preference for areas with enhanced current intensities. Within the study area, a general trend of northward decreasing mound heights and increasing abundance of erosive features can be observed.
High-resolution ROV (Remotely Operated Vehicle) video observations at four sites within the TOBI coverage illustrate that only the southernmost mound shows signs of active mound growth while the other mounds represent relict structures with limited coral cover opportunistically taking advantage of available hard substrate in the form of consolidated/lithified sediments. The distribution of erosion features, seabed features and seabed facies on the northwest Porcupine Bank indicates an environmental window in which the interplay of coral growth, sediment input and sediment preservation leads to the formation of mound sediments and therefore mound growth. Whereas too weak bottom currents do not support thriving coral thickets, too strong bottom currents hamper any deposition and, thus, mound growth. As this environmental window varies over time, mound sizes on the Porcupine Bank (and probably also in other mound settings) most likely reflect the duration in time of such an environmental window of optimal growth conditions around a given mound, rather than an indication of the overall age of the mound.
cold-water coral mound, erosion, environmental window, coral facies, iceberg ploughmarks, side-scan sonar, remotely operated vehicle, Porcupine Bank, NE Atlantic
9781402065118
0025-3227
218-229
Dorschel, B.
7e01530c-9162-4080-b06e-1d89cb4b9259
Wheeler, A.J.
17a38f47-d5cc-4bcb-b1a8-ddfb84851d99
Huvenne, V.A.I.
f22be3e2-708c-491b-b985-a438470fa053
de Haas, H.
7c8694dd-c8a1-48ec-a989-9593cbffd788
Dorschel, B.
7e01530c-9162-4080-b06e-1d89cb4b9259
Wheeler, A.J.
17a38f47-d5cc-4bcb-b1a8-ddfb84851d99
Huvenne, V.A.I.
f22be3e2-708c-491b-b985-a438470fa053
de Haas, H.
7c8694dd-c8a1-48ec-a989-9593cbffd788

Dorschel, B., Wheeler, A.J., Huvenne, V.A.I. and de Haas, H. (2009) Cold-water coral mounds in an erosive environmental setting: TOBI side-scan sonar data and ROV video footage from the northwest Porcupine Bank, NE Atlantic. Marine Geology, 264 (3-4), 218-229. (doi:10.1016/j.margeo.2009.06.005).

Record type: Article

Abstract

Cold-water coral mounds are common features in certain regions along the Atlantic margin. They occur in mound provinces in various settings, characterised by specific environmental conditions that steer and influence coral mound initiation, growth and demise (e.g. bottom current intensity, sediment input and food supply). In order to add detail to the diversity of environmental conditions described in relation to these structures, this study investigates mounds in a generally erosive setting on the northwest Porcupine Bank (NE Atlantic)—in contrast to previous studies in less hydrodynamically active settings.
TOBI (Towed Ocean Bottom Instrument) side-scan sonar data revealed abundant erosive features in the study area. They occur in the form of erosional scarps, erosional pits and locally scoured seabed. Furthermore, two large (several hundred metres high) and 101 small (tens of metres high) cold-water coral mounds were identified on the TOBI images. Most of the mounds are located on top of erosional scarps pointing to the cold-water corals' preference for areas with enhanced current intensities. Within the study area, a general trend of northward decreasing mound heights and increasing abundance of erosive features can be observed.
High-resolution ROV (Remotely Operated Vehicle) video observations at four sites within the TOBI coverage illustrate that only the southernmost mound shows signs of active mound growth while the other mounds represent relict structures with limited coral cover opportunistically taking advantage of available hard substrate in the form of consolidated/lithified sediments. The distribution of erosion features, seabed features and seabed facies on the northwest Porcupine Bank indicates an environmental window in which the interplay of coral growth, sediment input and sediment preservation leads to the formation of mound sediments and therefore mound growth. Whereas too weak bottom currents do not support thriving coral thickets, too strong bottom currents hamper any deposition and, thus, mound growth. As this environmental window varies over time, mound sizes on the Porcupine Bank (and probably also in other mound settings) most likely reflect the duration in time of such an environmental window of optimal growth conditions around a given mound, rather than an indication of the overall age of the mound.

This record has no associated files available for download.

More information

Published date: 15 August 2009
Keywords: cold-water coral mound, erosion, environmental window, coral facies, iceberg ploughmarks, side-scan sonar, remotely operated vehicle, Porcupine Bank, NE Atlantic

Identifiers

Local EPrints ID: 67257
URI: http://eprints.soton.ac.uk/id/eprint/67257
ISBN: 9781402065118
ISSN: 0025-3227
PURE UUID: 2dfa8e9f-0699-4e22-ba79-23308bf2581a
ORCID for V.A.I. Huvenne: ORCID iD orcid.org/0000-0001-7135-6360

Catalogue record

Date deposited: 07 Aug 2009
Last modified: 14 Mar 2024 02:49

Export record

Altmetrics

Contributors

Author: B. Dorschel
Author: A.J. Wheeler
Author: V.A.I. Huvenne ORCID iD
Author: H. de Haas

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.

×