Biddle & Swart investigate climate critical processes in the marginal ice zone around Antarctica, where the ice cover is advancing and retreating seasonally. This is a region where the lack of data is especially severe. Small sensors attached to elephant seals provided Biddle & Swart with ocean data down to 500 meter depth, including locations covered by floating sea ice. The data was retrieved by direct communication with the sensors over satellite.
For anyone feeling that the paper by Biddle & Swart is to heavy, The New York Times picked up this fascinating research in an article, doing a good job at explaining some of the scientific concepts.
We should point out that all scientific work with animals, not least mammals, is strictly regulated. The elephant seals are not harmed or effected negatively by the attached instruments.