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News Story - Seals help reveal secrets of the Southern Ocean

Date: 12 Aug 2008

Scientists have gathered data from under and around the sea ice in Antarctica using sensors attached to southern elephant seals (Mirounga leonina). Small sensors were attached to over 50 seals to collect oceanographic data about the Southern Ocean. Results are published this week in the journal Proceedings of the National Academy of Sciences.

The seals were tagged at the islands of South Georgia, Kerguelen and Macquarie in the Southern Ocean, and at the western coast of the Antarctic Peninsula. The international team of scientists glued electronic data loggers to the seals. The loggers measured temperature, pressure, and salinity and transmitted data along with seal positions to satellites when the animals surfaced. The researchers were able to collect data from a vast area of inaccessible ocean, including under the sea ice in winter.

Dr. Mike Meredith, Head of the Atmosphere and Ocean Group at British Antarctic Survey says, “The Southern Ocean is the hardest place in the world to obtain oceanographic data, especially during the wintertime. The seals acted as ‘samplers’ to collect data from deep seas that we couldn’t ordinarily access due to their remoteness and harsh environments. This data, and data from freely-drifting ocean floats, has increased our understanding of the frontal structures and ocean circulation in this part of the Southern Ocean, and provides a valuable record of sea ice dynamics around Antarctica.”

Scientists can now refine computer models of the Southern Ocean circulation, including more realistic treatments of the impacts of sea ice production.



This research is published in this week’s Proceedings of the National Academy of Sciences, in a paper led by Dr. Jean-Benoit Charrasin. It involved biologists and oceanographers from the following Institutes:
Gatty Marine Laboratory, Sea Mammal Research Unit @ St Andrews University (UK)
Centre d’Etudes Biologiques de Chize (France)
Antarctic Wildlife Research, School of Zoology (Hobart)
Center for Ocean Health, Institute of Marine Sciences (USA)
Laboratoire d’Oceanographie Physique Musée National d’Histoire Naturelle (France)
British Antarctic Survey (UK)
Commonwealth Scientific and Industrial Research Organisation (Hobart)
Antarctic Co-operative Research Centre @ University of Tasmania (Hobart)
Antarctic Ecosystem Research Division @ National Oceanic and Atmospheric Administration (USA)
Valeport Ltd (UK)

The research was funded by the Natural Environment Research Council.
For the South Atlantic component of this project, Dr Mike Meredith of the British Antarctic Survey worked with Mike Fedak, Martin Biuw, Phil Lovell and Lars Boehme from the Sea Mammal Research Unit at the University of St. Andrews. Eight elephant seals were tagged on South Georgia in 2004, and a further thirteen were tagged in 2005.

The sensors, the size of a pack of cards, were attached to the head of elephant seals. The device is attached with glue but falls off when the seals moult. They are small devices for such large and powerful animals, and have no impact.

The sensors ‘conductivity-temperature-depth satellite relay data logger’ (CTD-SRDL) provides high accuracy temperature and salinity readings via satellite. They were designed and built by the NERC Sea Mammal Research Unit and Valeport Ltd UK.

The Southern Ocean is one of the most productive of the world’s oceans, mainly a result of short, intensive spring phytoplankton blooms.

The NERC Sea Mammal Research Unit is a NERC Collaborative Centre that provides the UK’s main science capability in the field of marine mammal biology. One of its core objectives is to understand the causes and consequences of change in marine mammal populations. It has been a leader in the development of new ways to study marine mammals and has applied its expertise in projects worldwide. www.smru.st-and.ac.uk

British Antarctic Survey is a world leader in research into global issues in an Antarctic context. It is the UK’s national operator and is a component of the Natural Environment Research Council. It has an annual budget of around £40 million, runs nine science programmes and operates five research stations, two Royal Research Ships and five aircraft in and around Antarctica. More information about the work of the Survey can be found at: www.antarctica.ac.uk