Once fitted with miniature sensors, seals become animal oceanographers who record data about ocean conditions with every dive beneath the ice, providing scientists with unparalleled access to hard-to-reach polar regions.
“Just as they’re going about their normal activities, these animals are collecting oceanographic data and they’re doing this in the pack ice and regions where it would be very difficult, if not impossible to go to using current oceanographic technology,” explains Dan Costa, a professor at the University of California at Santa Cruz who pioneered this technique. Ship time is often limited in polar regions, cloudy skies can limit the utility of satellite remote sensing, and ice cover makes it difficult to use buoys or floats as research tools, Costa says.
For example, deep-diving Southern Elephant seals wearing sensors can obtain environmental data at depths of more than 900 meters. The sensors record data on ocean variables such as temperature and salinity, and transmit the information to polar orbiting satellites when the animal surfaces. Scientists can also use the data to learn more about the animals’ movements, foraging behaviors, and populations.
Costa and an international team of collaborators contributed to the IPY effort Marine Mammals Exploring the Ocean Pole to Pole (MEOP), a project designed to increase understanding of the oceanography of the Arctic and Antarctic using marine mammals as well as increasing our understanding of the biology of these marine mammals relative to their environment.
Tagged marine animals were an integral part of several MEOP studies, providing data on the conductivity, temperature, and depth of the ocean from sensors attached to hooded, Crabeater, Weddell and Southern Elephant seals could be used to study upper ocean properties such as seasonal variability in ocean heat content and sea ice production.