[12-08-2008 to 12-09-2008]
Seals help unlock secrets of the ocean
Elephant seals in the Southern Ocean are helping researchers to gather
essential data locked beneath the icy seas.
Sensors developed by the University of St Andrews have been employed by
Antarctic researchers to collect otherwise inaccessible information about
The instrumentation group of the University's Sea Mammal Research Unit has
created small data logging transmitters that can be used to measure the
physical properties of the ocean through which the seals swim.
Scientists usually collect data to characterise the ocean using satellite
sensing, buoyant floats, and ship expeditions, but winter sea ice renders
the Southern Ocean virtually impermeable to all three.
Professor Mike Fedak from the University's Gatty Marine Laboratory said,
"The Southern Ocean is a hotspot for climate research because its
circulation is critical to understanding the earths 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 instruments measure temperature, pressure, and salinity and transmit
data as well as seal positions to satellites when the seals surface. From
this, researchers are able to amass data for a vast range of hitherto
inaccessible ocean, including areas deep within the sea-ice in winter while
also learning about the animals themselves.
This new data has enabled them to follow the yearly rise-and-fall cycle of
sea ice production, and should help scientists refine computer models of the
Southern Ocean circulation.
Led by DrJean-Benoit Charrassin, a marine biologist at the Natural History
Museum in Paris, researchers in France, the UK, Australia and the US have
attached electronic dataloggers to 70 seals at the four most important
breeding colonies of southern elephant seals.
The species can dive as deep as 2 km in search of food while ranging across
much of the southern ocean. Thanks to this innovative technology, the only
remaining area with limited coverage is the Pacific sector, which contains
no islands for the seals to breed on.
Professor Fedak explained, "I think 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 the International Polar Year (IPY). "
The on-going MEOP project (Marine Mammals Exploring the Oceans Pole to
Pole) has equipped 100 seals of 3 polar species with oceanographic sensors
and these animals are now routinely sending large quantities of near
real-time information from the undersampled polar regions.
Professor Fedak continued, "The MEOP animals have contributed over 35
thousand observations from the polar seas in the past year, and I think it
is really fantastic to see how large a contribution the animals can make,
sending data from below the ice in near real time.
"These data are 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
"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."
The article "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. is published today by PNAS.
contact: Prof Michael Fedak