The UWA-developed underwater gliders
can be sent on deep sea missions
regardless of weather conditions.
Image: iStockphoto

In true 007 style, unmanned ocean gliders are being deployed on deep sea missions, scouting Australia’s ocean currents and collecting information to help scientists protect one of our most fragile environments.
 
Subsurface observations have previously been collected using ships, however limitations such as weather, routes, speed and cost saw collected data restricted to particular regions, with foul weather hampering the process.
 
Utilising Global Positioning System (GPS) and satellite communication technologies, scientists are now able to remotely control underwater ocean gliders, navigating them through different depths and recording ocean temperature, salinity, dissolved oxygen, turbidity, dissolved organic matter and chlorophyll, in near real-time.

Oceanographer and leader of the Australian National Facility for Ocean Gliders (ANFOG), UWA’s Professor Chari Pattiaratchi explains how the team is navigating ocean gliders through different depths along Western Australia’s Leeuwin current.

“Two sea gliders will be launched at three monthly intervals and GPS will be used to navigate the gliders back and forth across the Leeuwin current down the coast from Dampier to Fremantle,” he said.

“We are able to control its route as it has wings and a rudder, allowing it to move horizontally in a selected direction.”

The Leeuwin current, which transports lower saline water and heat, and the east coast’s East Australian Current (EAC), are the main currents feeding the Antarctic Circumpolar Current – the strongest and longest ocean current in the world. Both currents are essential for the sustainability of the fragile coastal ecosystem and fish populations.

Highly endangered coastal ecosystems such as WA’s Ningaloo Reef will benefit from the new ocean glider technology. Marine scientists are collecting data which will help them assess levels of phytoplankton as well as validating environmental satellite instruments that contribute to routine mapping of sub-surface temperatures.

Professor Pattiaratchi says “We hope to provide data to model the role of the ocean on climate variability, carbon levels, ecosystems and coastal environments.”

Ocean gliders are sustainable, relatively cheap, can be re-used and don’t rely on ships to monitor and service them continually.

ANFOG has two types of ocean gliders. The Slocum glider is specifically designed to monitor near-coastal environments, while the Sea gliders are designed to travel greater distances and dive up to 1000 metre depths.

Slocum gliders can be deployed for up to 30 days at a time, cruising at a maximum speed of 40cm/s. In comparison, Sea gliders can spend over six months at sea and cruise at 24cm/s.

According to Professor Pattiaratchi “Although the data collected by the gliders is not unique, the low cost and duration of their deployment will vastly improve the amount of data oceanographers are able to collect.”