CSIRO's Wealth from Oceans Flagship uncovered a treasure trove of creatures thriving on mountains deep under the ocean off south-eastern Australia.
Two Wealth from Oceans Flagship voyages aboard the Marine National Facility Research Vessel Southern Surveyor have given scientists a rare glimpse into the hidden world of our oceans.
The voyages were part of a project in collaboration with the Department of Environment, Water, Heritage & the Arts. It draws on the expertise of:
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Geoscience Australia
CSIRO scientists filmed around 100 hours of underwater footage and took 8000 photos.
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Museum Victoria
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the Australian Museum
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the Queensland Museum.
Voyages of discovery
The RV Southern Surveyor was at sea for two weeks in November 2006 and two weeks in April 2007. The survey areas were about 100 nautical miles off the coast of southern Tasmania in the Huon Commonwealth Marine Reserve (CMR).
The Huon CMR covers 12 780 km² of:
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outer continental shelf
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continental slope
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deeper seabed.
It contains the smaller Tasmanian Seamounts Marine Reserve, declared in 1999. This followed the voluntary closure by the fishing industry when the conservation significance of Australia's seamounts (undersea mountains) and the impacts of commercial bottom trawl fishing were first recognised.
Photographic images and biological samples were taken between 100 and 2 000 metres below sea level. CSIRO scientists filmed around 100 hours of underwater vision and took 8 000 individual pictures.
At least 418 invertebrate species from selected taxa were identified from the sampling on seamounts and adjacent deep water habitats. These included corals, sponges, crustaceans, seastars and molluscs). Of these 274 (66 per cent) are believed to be new to science.
A further 285 invertebrate species were identified from adjacent shallow water samples. Museum experts around Australia are working to confirm their identities.
Mountains of the deep
Researchers consider the Huon CMR an amazing location because it includes Australia’s largest known cluster of seamounts.
Most of these seamounts are cone-shaped remnants of extinct volcanoes. They can be up to 25 kilometres across at the base and rise 200 to 500 metres from the seabed.
Mapping of the seabed was only completed by the Flagship during the April 2007 voyage. It revealed 123 seamounts in 1 000 to 2 000 metre depths – most of which were previously unknown.
Seamounts provide hard, elevated and current-swept habitats for rich communities of filter-feeding corals and sponges on the predominantly flat and muddy floor of the deep sea.
The vision taken on the voyages in the Huon CMR has show that vast thickets of stony corals are found on many seamounts to depths of 1 400 metres. Coral thickets resemble shallow tropical coral reefs and provide habitat for a great diversity of smaller mobile animals including crustaceans, brittle stars, urchins and molluscs.
Stony coral habitats have been largely removed from shallow seamounts by Orange Roughy trawling, but many other deeper seamounts are in pristine condition.
Ongoing monitoring
By using non-extractive photographic sampling techniques CSIRO scientists are able to measure change in this marine reserve over time without impacting on the environment.
The next Flagship voyage to the Huon CMR will be in seven years, when it is hoped there will be evidence of recovery in the areas of the reserve affected by fishing before the reserve was declared.
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