Australian researchers have returned from a six-week marine science voyage investigating the critical role of ocean life in capturing atmospheric carbon.
In the most extensive study of its kind undertaken in the Southern Ocean, twenty researchers on board the CSIRO research vessel Investigator deployed a suite of sensors, instruments and robotic floats at three separate locations.
A key focus of their research is the enigmatic region just beneath the ocean's sunlit surface known as the "twilight zone." This region is also home to a variety of marine life and plays a key role in carbon sequestration.
Voyage Chief Scientist, Professor Philip Boyd, from IMAS and AAPP, said it was the first voyage of its kind to bring together ship-board ocean measurements, biological sampling, deep-diving robots, automated ocean gliders and satellite observations.
"We set out with ambitious science objectives for this voyage, and we could not be happier with the outcome," said Professor Boyd.
"One of the long-term payoffs is the big technological advances we are making using new remote robotic sensors to study the role of ocean life in the climate. The ocean plays a role in the global carbon cycle that is every bit as important as the forests on land. We are only beginning to understand this role, but we know that marine life helps remove about a quarter of all the carbon dioxide that humans emit by burning fossil fuels."
Professor Boyd added that the driving force behind the removal of CO2 is the billions of tiny plankton that capture carbon from the atmosphere through photosynthesis. When these organisms die, or are consumed by other organisms, the heat-trapping carbon particles form a "marine snowfall" that sinks into the ocean's twilight zone.
A fraction of this heat-trapping carbon continues to the sea floor, where it can be sequestered for hundreds or thousands of years.
The researchers took biological samples and measurements from three different locations in the Southern Ocean, and also deployed a fleet of deep-diving ocean robots equipped with a new generation of bio-optical scientific instruments. This fleet of deep-diving robots and gliders will spend the next few years transmitting data from the remote ocean, allowing the team to continue their research remotely.
"We are also developing innovative ways to link all of these data sets, which will reveal all sorts of information about how ocean life sequesters atmospheric carbon dioxide," Professor Boyd said.
The Southern Ocean Large Areal Carbon Export (SOLACE) voyage is scheduled to arrive around midday on Friday, January 15. The project includes contributions from CSIRO, the University of Tasmania's Institute for Marine and Antarctic Studies (IMAS), the Australian National University (ANU), Curtin University and the Australian Antarctic Program Partnership (AAPP).
This research is supported by a grant of sea time on Investigator from the CSIRO Marine National Facility.