Geomorphic and habitat mapping of submarine canyons of the Australian continental margin

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Abstract

Submarine canyons inﬂuence oceanographic processes, sediment transport, productivity and benthic biodiversity from the continental shelf to the slope and beyond. The relative inﬂuence of an individual canyon on these processes will, in part, be determined by its form, shape and position on the continental margin. Based on the latest bathymetry data for the Australian margin, we have mapped 753 submarine canyons and derived a large number of geomorphic metrics based on canyon form, shape and position. In this presentation we highlight key results, which show that these canyon metrics describe a wide variety of canyon form and physical complexity that is consistent with the geological evolution of the Australian margin and the local inﬂuence of geological and geomorphological processes. Thus, Australian submarine canyons cluster in the east, southeast, west and southwest where the margin is steepest and continental shelf is narrow. Subsequently, we used 22 environmental variables (including many of the geomorphic metrics) as surrogates to derive estimates of habitat potential for these submarine canyons. Our analysis shows that the high geomorphic and oceanographic diversity of Australian submarine canyons creates a multitude of potential habitat types, notably for benthic infaunal and epifaunal communities. Canyons with particularly high benthic habitat potential are located mainly offshore of the Great Barrier Reef and the New South Wales coast, on the eastern margin of Tasmania and Bass Strait, and on the southern Australian margin. Many of these canyons have complex bottom topography, are likely to have high primary and secondary production, and have less potential for sediment disturbance due to bottom current. Canyons that incise the shelf tend to score higher in habitat potential than those conﬁned to the slope. This habitat potential is exempliﬁed by Perth Canyon, a large shelf-incising canyon on the southwest Australian margin, which we present in this talk as a case study. High-resolution (20m) multibeam sonar data for the canyon reveals the geomorphic complexity characterised by escarpments, transverse ridges, large-scale mass movements and active bedform ﬁelds. This geodiversity and the interaction of the Perth Canyon with regional oceanographic currents (the Leeuwin Current and Undercurrent) provide highly diverse habitats for benthic fauna such as deep-sea corals and sponges and a variety of pelagic fauna including cetaceans (e.g., Australian pygmy blue whales, minke whales, sharks and tunas). Abstract submitted to/presented at the 2018 International Network for Submarine Canyon Investigation and Scientific Exchange (INCISE) Symposium (https://www.incisenet.org/)

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document

eCat Id

122817

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

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Keywords

theme.ANZRC Fields of Research.rdf

EARTH SCIENCES

( Feature type )

Submarine Canyon

( Discipline )

Geomorphic Mapping

( Discipline )

Habitat Mapping

Published_External

Publication Date

2023-11-01T05:47:54

Creation Date

2018-09-14T09:00:00

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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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Status

completed

Purpose

Abstract for the INCISE 2018 Symposium

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notPlanned

Topic Category

oceans

Series Information

2018 International Network for Submarine Canyon Investigation and Scientific Exchange (INCISE) 5-7 November 2018 Shenzhen, Guangdong, China

Lineage

This abstract has been submitted to the INCISE 2018 symposium. The abstract contains the highlights of several previous and current studies on Australian submarine canyons. I have presented an oral talk in the symposium (Shenzhen, China, November 5-7). Citation: Huang, Z., Schlacher, T.A., Nichol, S., Nanson, R., Harris, P.T., Julian Caley, M., Williams, A., Althaus, F., Kloser, R., 2018. Geomorphic and habitat mapping of submarine canyons of the Australian continental margin, 4th International Submarine Canyon Symposium (INCISE2018), Shenzhen, China, November 5-7.

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[-54.75, -9.2402, 112.92, 159.11]

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Download Abstract (pdf) [422.7 MB]

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