Science Snippet
Written by Dr Clive Mcmahon
Macquarie Island Elephant seals provide crucial oceanographic and biological information from the Southern Ocean.
The oceans, in particular the Southern Ocean, are an essential part of Earth’s climate. Animal Borne Ocean Sensors that measure temperature, conductivity (salinity) and depth provide information that helps us monitor, understand and model ocean heat content, ocean current formation, sea ice production and to integrate this with at-sea animal behaviour to determine how changes in the ocean affects ocean productivity, prey field distributions and density and animal performance. In May 2023, 21 clever miniaturized conductivity-temperature-depth sensors were deployed to southern elephant seals at Macquarie Island in May 2023 aiming to:
Provide essential high-resolution ocean observations south of 60°S, along the East Antarctic Coast between 110°E - 150°W in an area that is essentially impossible to monitor reliably by conventional means during the autumn, winter and spring when the seasonal ice zone expands to cover an area nearly three times that of Australia
Provide data integrating animal behaviour and ocean physics, describe Southern Ocean water masses and provide essential bathymetric observations along the Antarctic Coast
Integrate cryospheric, oceanographic, and physiographic factors to understand Antarctic Bottom Water formation and basal melt of ice shelves
Since May the seals have ranged widely across the Southern Ocean and routinely dived to depths of 1000 m and in some cases even deeper to 1700 m collecting the all-important information oceanographers and biologists need to study and understand our oceans and the animals that live in them. The information is returned in almost near-real time every six hours via the Argos satellite constellation and made freely available to the global community.
These data that seals collect improve our understanding of the ocean’s role in climate and the evolution of climate change on decadal time-scales. The seal derived observations encompasses the continental slope and shelf regions around Antarctica, most of which may never be sampled without the seals. These Seal derived observations are used widely by the international community including operational ocean forecasters through the Global Telecommunications System in real time and in delayed mode the observations are routinely assimilated into international climate, weather and ocean forecasting models.
The programme at Macquarie Island is a collaboration between the Integrated Marine Observing System, the Australian Centre for Excellence in Antarctic Science, the Australian Research Council, the Australian Antarctic Division and the Sydney Institute of Marine Science.
Credits – animation David Green, University of Tasmania. Photos, Rob Harcourt, Macquarie university