Associate Professor Stefan Williams, from the Australian Centre for Field Robotics, University of Sydney, working with the Autonomous Underwater Vehicle. IMOS uses this robot to take high resolution images of benthic habitats. Photo Credit Kim Brooks, Australian Institute of Marine Science.


Can the Great Barrier Reef recover from devastation?

A reconnaissance mission by an underwater imaging robot hopes to discover a more resilient reef than feared, following devastation by Cyclone Yasi in February last year.

Sirius is a robotic autonomous underwater vehicle that operates as part of the Integrated Marine Observing System (IMOS). It will set sail from Townsville this week to record the recovery of deeper parts of the Great Barrier Reef.

Sirius will revisit the outskirts of the Reef, where five years ago it discovered coral reefs down to depths of 150 metres. It cruises two metres above the seabed without requiring input from a human operator, and collects vital before-and-after data that helps scientists calculate the actual health of the world’s largest reef system.

“After Yasi, we returned to these outskirt reefs and used Sirius to photograph the effects of the cyclone. In some places, it looked as though it had been sandblasted clean, with no sign of coral or rubble for kilometres,” explains Dr Tom Bridge from James Cook University’s ARC Centre of Excellence for Coral Reef Studies.

“Sirius photographed coral damage down to 60 meters in the deeper reefs, which is very unusual, and goes to show the severity of the category five cyclone.”

These deeper reefs are thought to almost double the area of the Great Barrier Reef and offer refuge to corals and other reef species against extreme events like Cyclone Yasi and the effects of coral bleaching, which is defacing the shallower reefs.

It is hoped that these deeper reefs have started to regenerate and researchers are expecting to find that the darker, colder conditions will protect corals from bleaching, which is associated with a combination of warmer temperature and sunlight.

“Undertaking research missions such as this requires many different disciplines to come together – people who study the ocean, people who build robots, people who specialise in data modelling,” says Mr Tim Moltmann, Director of IMOS.

“Our collaborative approach allows us work with, and make decisions based on, the best and most up-to-date data.

“There is still much to learn about Australia’s marine territory so it’s very important that we have a national observing project that collects this information and makes it available to all researchers and governments,” he says.

Associate Professor Stefan Williams, from the University of Sydney’s Australian Centre for Field Robotics says that the more data Sirius collects, the more scientists, governments and fisheries can learn.

“This data tell us a lot about what the underwater terrain looks like and factors that threaten or contribute to the Reef’s health, including climate change,” he says.

“The robot will take thousands of pictures of specific sites that it has visited in the past so that marine biologists and ecologists can compare them to previous images and determine any changes.

“Sirius uses high resolution cameras, sonar and GPS to guide itself – it also monitors water temperature, salinity andthe concentration of various elements or compounds,” he explains.

Sirius is one of 12 observing facilities that have been monitoring multiple sites along Australia’s East and West coasts for the past six years. Funded by IMOS, the data collected from these facilities is stored on a publicly accessible database.

IMOS is supported by the Australian Government through the National Collaborative Research Infrastructure Strategy and the Super Science Initiative. It is led by the University of Tasmania on behalf of the Australian marine and climate science community.

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