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Highlights
Expedition reveals methane bubblng from the timor Sea
Pioneering research in the Oceanic Shoals bioregion, which extends
across the top of Australia’s marine territory in the Timor Sea and
down the west coast to the Rowley Shoals west of Broome, has observed
for the first time seeps of natural gas streaming to the surface from
the seafloor in 90 m water depth, about 300 km north of Broome.
Underwater cameras revealed gas and fluid squirting from the seafloor,
and bubbles of the gas were directly collected as they rose to the
surface and analysed, with surprising results – they are virtually
pure methane (99%) laced with other hydrocarbons.
This finding has implications for global warming since methane is
20 times more powerful than CO2 as a heat-trapping
greenhouse gas. It is believed these seeps may occur throughout the
continental shelf of this remote region that has proven to be a
biodiversity hotspot.
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The observation of
active seeps builds on new knowledge being developed by a
multidisciplinary effort team to describe and map biodiversity and
to pursue the question of the role that hydrocarbons might play in
the natural environment of one of Australia’s largest oil and gas
provinces.
A commercially important Scampi, carid shrimp and numerous
brittle stars show their true colours when captured on camera in
410m of water near the Sahul Banks, Timor Sea.
Photo: M. Rees
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AIMS’ biogeochemist Dr Gregg Brunskill and oceanographic
technician Cary McLean use a ‘bubble catcher’ to sample methane
bubbles rising from a submarine seep on the seafloor of the
Timor Sea. A small half-square kilometre patch of seafloor
seepage was delivering about 1 tonne per day of greenhouse
methane to the atmosphere, from several kilometers beneath the
seafloor.
Photo: B. Bennett
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Researchers have also discovered dense
patches of coral reef and expanses of Haimeda algae to around
60m depth on many of the submerged shoals.
Fish communities are diverse, many
observed for the first time in Australian waters, and important
commercial fish species were found to be abundant in deeper water. A
better understanding of how oily hydrocarbons and methane influence
marine life will contribute to wise management of this resource rich
region.
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