In a groundbreaking effort to understand the role of ocean currents in climate dynamics, the CSIRO research vessel (RV) Investigator, part of the FOCUS voyage, has completed a comprehensive survey of a section of the Southern Ocean, known for hosting the world's strongest current.
This voyage, which lasted five weeks, was a collaboration involving Australian and international teams, including NASA and the French space agency Centre National d’Études Spatiales (CNES).
Situated between Tasmania and Antarctica, the surveyed area encompasses 20,000 square kilometres, extending from the ocean surface to the seafloor, about 4,000 metres below.
This study was conducted in the Antarctic Circumpolar Current, aiming to understand how the transfer of heat across this natural barrier contributes to the melting of Antarctic ice shelves and potential sea-level rise.
Current investigation voyage. ✅An Australian and international research voyage on #RVInvestigator has mapped a highly energetic "hotspot" in the world’s strongest current simultaneously by ship and satellite, and uncovered an underwater mountain range. https://t.co/QPfk5MKb38
— CSIRO (@CSIRO) December 19, 2023
Ocean - a climate shock absorber
A key aspect of the FOCUS voyage was its collaboration with the Surface Water and Ocean Topography (SWOT) satellite.
This partnership enabled simultaneous mapping of ocean features by both the satellite and the ship.
Dr Benoit Legresy, the voyage chief scientist from CSIRO, highlighted the importance of this research in tracking heat and carbon pathways in the global climate system, emphasizing the ocean's role as a "climate shock absorber".
Ancient seamounts
The survey not only mapped ocean currents but also revealed previously unknown features of the sea floor.
Dr Chris Yule, a geophysicist with CSIRO, reported the discovery of a chain of ancient seamounts, including eight dormant volcanoes.
This finding expands our understanding of the area's geological history.
Understand climate change
Dr Helen Phillips, co-chief scientist of the voyage from the Australian Antarctic Program Partnership at the University of Tasmania, underlined the importance of these discoveries for understanding ocean dynamics
The interaction of the Antarctic Circumpolar Current with undersea topography, such as ridges, seamounts, valleys and cliffs, influences the formation of eddies and the movement of heat and carbon in the ocean.
While the full integration of ship and satellite data will require time, this successful expedition marks a significant advancement in understanding ocean circulation and its implications for climate policy.
The knowledge gained from this research is expected to assist in planning for rising sea levels and climate change adaptation.