Polar oceans might feel like they are long way away, but small changes at high latitudes can have disproportionately large global climate consequences. Many of the recent extreme weather events in the northern hemisphere (long cold spells, massive snow dumps, heat-waves, and flood events) are thought to have been triggered by a 'jammed' jetstream, linked to a warmer Arctic Ocean and a diminishing coverage of sea-ice, for example. But monitoring the changes in these inhospitable polar environments is a major challenge. Now seals are giving us a helping hand.
Since 2003 scientists at the Sea Mammal Research Unit at the University of St Andrews, have been gluing unobtrusive data gathering tags (which record temperature, salinity and pressure) onto the heads of seals. They started their project with Southern Ocean elephant seals, which spend 90% of their lives at sea, covering vast distances and diving down as far as 2000m, up to 60 times per day. Each time a seal comes up from a dive its data is transmitted to a satellite and made freely available, for immediate use by weather forecasters and ship operators.
One decade on and this project is proving its worth. As well as improving our weather forecasts, the seals have created a detailed map of ocean circulation in the Southern Ocean, helping scientists to understand its impact on southern hemisphere climate. And the seals benefit too: the data is providing new insights into their lifestyles and behaviour, helping to shape conservation policy.