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Research Voyages

MAPPING SEABED HABITATS OFF wEST AUSTRALIA SS07/05 Jul 05

[Introduction] [The Voyage] [The Voyagers] [Ship to shore]

Ship to shore

Day 10 - Cranking on through the night
by Bruce Barker

The CMAR towed camera system being launched from the rear deck of Southern Surveyor. Matt Sherlock supervises as Graeme McDougall (left) and Bruce Barker (right) manage tether ropes.

A typical sponge and octocoral community from tropical shelf edge seafloor, ~115 m depth.

An arrow squid jets backwards to create a sediment plume from the soft muddy sediments in at ~ 708 m.

Getting ready to deploy, as the last of the day fades away.

I am shift leader on this voyage. My working day begins at 2 am when I discuss the previous shifts activities with Alan Williams - the voyage Leader. We plan the work for the next 12 hours.

Our shift team includes the "camera crew", of which I am part , and a part of the work plan is to identify the sites for a series of camera transects. Sites are identified using information collected with the swath mapping system. We distinguish features and different bottom types from the swath data. The camera system then enables us to verify those features, and to observe the biological communities living on and near the seafloor.

The towed-camera system (developed in-house by CMAR) has incorporates the latest technologies to allow us to view the seabed in real time and to record high quality imagery at depths to 1500 meters.

Matt Sherlock (CMAR electronics engineer) and Jeff Cordell (CMAR electronics technician) worked busily for several months preparing the system for this voyage. The system captures spectacular high-quality video from stereo-cameras and marvellous high-resolution still images from the digital-stills camera. The system also incorporates several other sensors to measure water characteristics, such as salinity and water temperature. Because there is virtually no light at the depths we operate, the system has powerful flood-lights and strobe-lights to illuminate the seafloor. It must be a huge shock to those animals down there when our camera system looms into their world with piercing laser beams and flood-lights blazing.

The camera is deployed from the stern of the vessel and is towed with a steel-armoured cable containing several conducting wires and two optic fibres. The optic-fibres are hardly thicker than one hair. Never-the-less they can carry video from several cameras simultaneously and still maintain high-quality imagery, after being transmitted through ourlong (3000 meter) connection.

We tow the camera system, behind the research vessel, at about 2 knots and fly it just above bottom using a joy-stick controller. We manually trigger our digital-stills camera when we see interesting features or animals and eagerly await the images that arrive, after a pause of only a couple of seconds. The real-time video display also attracts plenty of interest from a huddle of scientists around the computer marvelling at the creatures and the quality of the imagery.

It is exciting to watch the footage, as the system is flown across sub-sea canyons, sea-mounts and the often steeply sloping regions where the continental-shelf drops away to the deep ocean. No one has seen the seafloor and animals - in their natural state - in most of the deep-water environments around Australia.

During this voyage we are acquiring data from the videos to analyse, so every minute of video is reviewed and data extracted by Franzis Althaus, who is on the voyage for this purpose. Thousands of still-images are also scrutinized to enable our on-board fish and invertebrate taxonomists to identify the seafloor animals and fish. Karen Gowlett-Holmes, our invertebrate specialist, has been busy identifying animals both from images and from the live animals collected in sediment grabs. Karen will be telling her story next week.

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Updated: 29/03/07