Research Voyages

Meteorological instruments high on the masts measure wind speed and direction and air temperature, pressure and humidity.

An ocean sampler for measuring water salinity, temperature and oxygen levels.

Deep-sea camera system.

Seabed map produced using the multi-beam swath-mapper.

The deep towed body uses sound to detect and distinguish between major groups of fish species.

Continuous measurements

A suite of instruments gather data continuously while the ship is under way. A GPS (global positioning system) ensures all measurements taken from the ship are referenced with precise times and accurate positions. Meteorological instruments high on the masts measure wind speed and direction and air temperature, pressure and humidity.

Beneath the ship, acoustic devices are used for bathymetry, to map the seabed, and to measure the strength and direction of the currents. Surface waters are monitored with a thermosalinograph for temperature and salinity, a fluorometer for chlorophyll concentration, and a transmissometer for water clarity.

Special operations

Additional instruments are deployed from the vessel at places of particular scientific interest, to sample, measure and map ocean features including water conditions, marine life, seabed topography and habitats. Here are some examples.

Ocean sampler

The Southern Surveyor uses this water sampling device to measure ocean conditions, from the sub-Antarctic to the tropics.

The ocean sampler takes precise measurements of water salinity, temperature and dissolved oxygen levels. It is deployed to depths of about 6000 metres on a frame or 'rosette' that also carries canisters for collecting water samples.

The vessel remains stationary while the rosette is lowered to a series of depths, a process that can take up to three hours. During its descent, the sampler relays measurements to the ship's operations room via a conductive cable, giving scientists onboard a continuous profile of the changing water properties. Water samples are collected for further chemical and biological analysis, and for calibrating the instrument's electronic sensors.

With the information collected by these instruments, oceanographers can build a picture of ocean circulation, such as the location and strength of currents and deep water masses that influence climate and climate change. By linking ocean physics, chemistry and biology, the system offers clues to how ecosystems function at the microscopic beginnings of the marine food chain.

Multi-beam swath-mapper

The swath mapper is an acoustic device installed beneath the ship which uses sound waves to profile large areas of seabed. It is 'driven' and monitored from the operations room.

The ship travels at 8-10 knots while the swath mapper is in operation, producing a map of the seabed four times as wide as the water depth. On a seabed mapping voyage, the swath mapper may be used for up to 20 hours at a time to map some 150 square kilometres of the ocean floor. The resulting maps look similar to topographic maps of the land, revealing ocean ridges and sunken canyons, and the composition of the seabed, such as hard rock, reef or soft sediment.

The seabed images appear on computer monitors in the operations room, opening a window to the world below. These maps, plus information about current strength and direction, are needed to enable the precise positioning of instruments towed behind the ship, such as the towed body and deep-sea camera system.

Deep towed body

The deep towed body is deployed behind the ship on an armoured optical fibre cable. This instrument has four sound frequencies and is designed to detect and distinguish between major groups of fish species.

"The towed body is travelling about one kilometre behind the ship, being moved around by the currents,"says acoustic scientist Rudy Kloser.

"It's like towing a trailer on a kilometre-long rope on a winding road and expecting it to follow you around the bends."

"We use a system of set and drift, supported by a combination of calculation and the expert knowledge of the Master."

The towed body was used on a Southern Surveyor voyage in July-August 2004 to investigate blue grenadier populations and ecosystems off Tasmania's west coast. It also has been used in orange roughy stock assessments.

Deep-sea camera system

The deep-sea camera system is 'flown' just above the seafloor, usually for an hour or so for 3–5 kilometres at a speed of about one knot. The video images are relayed to monitors in the operations room. Operators watching the video can trigger a digital still camera to photograph objects of particular interest.

Last November, the camera system gave scientists their first view of giant crab habitats at the edge of the continental shelf off Tasmania. Fished and unfished areas were surveyed to help understand the crab's place in the ecosystem and the effects of fishing.

Swath mapping, deep-sea imaging and biological sampling are used together to determine links between particular seabed types, habitats and marine communities.

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