Physical Controls on Coral Communities on the George V Land Slope: Some Working Hypotheses

Authors / CoAuthors

Post, A.L. | O'Brien, P.E. | Beaman, R.J. | Riddle, M. | De Santis, L.

Abstract

Dense coral-sponge communities on the upper continental slope off George V Land have been identified as a Vulnerable Marine Ecosystem in the Antarctic. The challenge is now to understand their likely distribution. The CEAMARC survey found these communities at sites on the upper slope in depths of 570 - 950m. Based on these results we propose some working hypotheses defining the physical settings suitable for such assemblages. Icebergs scour to 500m in this region and the lack of such disturbance is probably a factor allowing growth of rich benthic ecosystems. In addition, the richest communities are found in the heads of canyons. We suggest two possible oceanographic mechanisms linking abundant filter feeder communities and canyon heads. The canyons in which they occur receive descending plumes of Antarctic Bottom Water formed on the George V shelf and these water masses could entrain abundant food for the benthos. Maps of water properties measured during the Collaborative East Antarctic Marine Census (CEAMARC) survey provide some support for this idea. Another possibility is that the canyons harbouring rich benthos are those that cut the shelf break. Such canyons are known sites of high productivity in other areas because of a number of oceanographic factors, including strong current flow and increased mixing, and the abrupt, complex topography. These hypotheses provide a framework for the identification of areas where there is a higher likelihood of encountering these Vulnerable Marine Ecosystems.

Product Type

nonGeographicDataset

eCat Id

69269

Contact for the resource

Custodian

EGD

Owner

Commonwealth of Australia (Geoscience Australia)

Custodian

Commonwealth of Australia (Geoscience Australia)
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Keywords

External PublicationReport

( Theme )

geomorphology

( Theme )

abiotic surrogates

( Theme )

Antarctic data

( Theme )

marine

Australian and New Zealand Standard Research Classification (ANZSRC)

Earth Sciences

Published_External

Publication Date

2009-01-01T00:00:00

Creation Date

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Australian Government Security ClassificationSystem

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence

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Use - license

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Purpose

Maintenance Information

unknown

Topic Category

geoscientificInformation

Series Information

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Unknown

Parent Information

Extents

[-67.5, -65.0, 139.0, 147.0]

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Spatial Resolution

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