Scientists use seals to unlock ocean secrets

REUTERS

An elephant seal is seen fitted with a sensor device used to monitor where it hunts and eats, and to measure temperature, salinity and pressure of the ocean during deep dives for food.

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Singapore - Scientists are outfitting elephant seals and self-propelled water gliders with monitoring equipment to unlock the oceans’ secrets and boost understanding of the impacts of climate change.

Oceans regulate the world's climate by soaking up heat and shifting it around the globe. They also absorb huge amounts of planet-warming carbon dioxide, acting as a brake on the pace of climate change.

But scientists say they need to ramp up a global monitoring network, with the Southern Ocean between Australia and Antarctica playing a key role. The Southern Ocean is a major “sink” of mankind's carbon emissions and an engine of the world's climate.

“To understand the rate of climate change, we need to understand these ocean processes, like how fast it can sequester heat and carbon,” said oceanographer Susan Wijffels, a group leader for Australia's Integrated Marine Observing System, or IMOS.

“So what the ocean does affects how fast the system can move and the regional patterns of climate change,” she told Reuters on Friday by telephone from a climate conference in Hobart, Tasmania.

Scientists also need to better understand natural ocean cycles that affect weather on land to improve long-term forecasts for crops and water management for cities.

IMOS groups researchers across Australian universities and research bodies and also links scientists in the United States, Asia and Europe.

A recent funding boost means the team can outfit about 100 elephant seals to collect data from the depths around Antarctica.

A small device with an antenna is attached to the heads of the seals to measure temperature, salinity and pressure as the animals dive for food.

Self-propelled gliders about two metres long will also be deployed in the seas around Australia to a depth of up to 1 500 metres to take measurements.

Fitted with wings and a rudder, the gliders can stay at sea for months and can be controlled remotely.

A key focus is the area of sea ice around Antarctica where existing self-propelled measurement devices, called Argos, can't easily function because they need to surface regularly to send data to satellites.

Argos are cylinders that rise and fall to depths of up to 2km. Thousands have been deployed globally.

New types of Argos are being developed that can “sense” breaks in the sea ice to send their data.

“The oceans under the ice are actually a blind spot in the global and national observing systems,” Wijffels said.

“We're starting to suspect the ocean is carrying heat into the sea ice zone,” she added, and this could be playing a role in destabilising the vast iceshelves of Greenland and Antarctica.

Scientists say Greenland has enough ice to raise sea levels by 7 metres if it all melted. Rising amounts of carbon dioxide are also making oceans more acidic, affecting sea creatures' ability to make shells and there are fears increased acidity could curb the ocean's ability to mop up carbon.

The programme also aims to boost monitoring of major currents around Australia that shift heat around the planet, including through the Lombok Strait near Bali in Indonesia, via deep-ocean moorings.

Such measurements were more common in the North Atlantic but the Southern Hemisphere remained a major gap, Wijffels said. - Reuters