Australia leads on Southern Ocean carbon dioxide monitoring
Australia’s Marine National Facility research vessel, Southern Surveyor, returned to the Southern Ocean in July to deploy three IMOS deep water moorings anchored at a depth of nearly five kilometres, about 580km south-west of Tasmania.
The moorings are an important part of the IMOS system and provide enhanced monitoring of the Southern Ocean. The moorings include the Air-Sea Flux Station, the Pulse biogeochemical sensor mooring and a deep sea sinking particle flux mooring. With the Education Investment Funding IMOS received in 2009, IMOS was able to invest in a second Air-Sea Flux Station mooring to allow the moorings to be hot-swapped. Prior to this the single mooring would have been deployed for a year at a time, then retrieved and taken back to land for servicing and then deployed several months later, creating gaps in the time series. This voyage deployed the new Air-Sea Flux station for the first time, enabling IMOS to provide a continuous time series of meteorological information in the Southern Ocean.
The leader of the Deep Water Mooring IMOS Facility, Professor Tom Trull, said the project was the only one of its type in the Southern Ocean.
“While the Southern Ocean plays a significant role in the global climate system, there is a paucity of sustained observations in this harsh and remote region. These high quality observations are a valuable contribution to understanding ocean processes that contribute to climate variability.
“The ability of the ocean to soak up carbon dioxide from the atmosphere and remove it to ocean depths is a natural process but the rate of that exchange and its influence on other chemical and biological properties in the ocean is now a central climate science question.
“We know the sub-Antarctic ocean is a hotspot for uptake of carbon dioxide and deployment of these mooring systems over the next 18 months will give us an insight into changes occurring from day-to-day and season-to-season in the upper ocean and at the sea surface.
“The results we obtain will be of interest around the world to climate and carbon cycle scientists,” Professor Trull said.