Seals help unlock secrets of the ocean

12 August 2008

Data collected from sensors attached to elephant seals in the Southern Ocean is helping researchers learn more about ocean circulation and the Earth's climate.

Scientists often use satellite sensing, buoyant floats and instruments on ships to find out about the physical properties of the ocean, but during the Antarctic winter using these methods to look under the ice is virtually impossible. Predatory elephant seals travel through vast areas of the Southern Ocean - including under the ice - so this novel approach opens up areas of the ocean that are usually out of bounds to researchers.

The project was led by Dr Jean-Benoit Charrassin, a marine biologist at the Natural History Museum in Paris and included a team of researchers from France, the UK, Australia and the US. The team included Professor Mike Fedak of the Natural Environment Research Council's Sea Mammal Research Unit at the University of St Andrews.

Professor Fedak said, "The Southern Ocean is a hotspot for climate research because its circulation is critical to understanding the Earth's climate and its huge ice sheet is sensitive to climate change.

"Southern elephant seals are wide-ranging predators that roam all over the Southern Ocean, even under the sea ice in the wintertime - a time when conventional ocean observation methods are unable to gather data."

The sensors measure temperature, pressure and salinity and transmit data - including the positions of seals - to satellites. The transmitters were developed by the instrumentation group at the Sea Mammal Research Unit and were attached to 100 seals at four large elephant seal breeding colonies in the Southern Ocean. The only area with limited coverage using this method is the Pacific Ocean, which has no islands for elephant seals to breed on.

The data collected so far has helped scientists follow the yearly rise and fall cycle of sea ice production and could improve computer models of the Southern Ocean circulation. The method is also helping researchers understand more about the seals' wide-ranging hunting habits. Elephant seals can dive as deep as two kilometres in search of food while ranging across much of the Southern Ocean.

Professor Fedak explained, "This is an extremely exciting new approach for ocean observation which has now been extended to seals roaming the seas around both poles as part of International Polar Year (IPY)."

"Data from the sensors is automatically distributed all over the world via the World Meteorological Organization (WMO) Global Telecommunication System (GTS) to operational forecasting centres where they can be assimilated into models that are run to provide ocean forecasts and long-range seasonal and climate predictions.

"The idea that these animals have become our partners in providing real time data about the state of our climate while simultaneously helping us to understand their ecological requirements has captured the imagination of biologists, oceanographers and the public."

Further information

Professor Mike Fedak
Tel: +1 518 532 0525

Lars Boehme

Martin Biuw
Tel: +47 777 50542

Fiona Armstrong
University of St Andrew Press Office
Tel: 01334 462530 / 462529
Mob: 07730 415015

NERC Press Office
Natural Environment Research Council
Polaris House, North Star Avenue
Swindon, SN2 1EU
Tel: 01793 411561
Mob: 07917 557215

Notes

1. "Southern Ocean frontal structure and sea ice formation rates revealed by elephant seals" by J. B. Charrassin, M. Hindell, S.R. Rintoul, F. Roquet, S. Sokolov, M. Biuw, D. Costa, L. Boehme, P. Lovell, R. Coleman, et al. was published 12 August 2008 by PNAS.

2. The Natural Environment Research Council (NERC) funds world-class science, in universities and its own research centres, that increases knowledge and understanding of the natural world. It is tackling major environmental issues such as climate change, biodiversity and natural hazards. NERC receives around £400m a year from the government's science budget, which is used to provide independent research and training in the environmental sciences.

Seals help unlock secrets of the ocean

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