IMOS: How seals are changing the way we monitor the Southern Ocean

IMOS (Integrated Marine Observing System) operates a wide range of ocean observing equipment throughout Australia’s coastal waters and also the open oceans. This fully integrated, national system, covers physical, chemical and biological ocean sciences forming the basis for robust and informed study of the worlds oceans. Of particular interest in understanding global climate processes is the Southern Ocean (SO), but studying this remote region is difficult and most observations are collected during the short ice-free summer when the region is accessible. Through Winter and Spring it is extremely difficult to collect biophysical ocean information in the Southern Ocean. The importance of good observations from this region, the home of the Antarctic Circumpolar Current (ACC), the largest current system in the world, which connects water masses from the global ocean basins cannot be over emphasised. IMOS through the Australian Animal Tracking and Monitoring System (AATAMS) has made important inroads into collecting otherwise hard to obtain observations from the SO by using CTD bio-loggers to monitor coastal and oceanic movements of marine animals from the Australian mainland as far south as the Antarctic continent. In particular seals equipped with satellite-linked CTD tags have provided unique temporal and spatial coverage of the Southern Ocean. This includes extensive data from the Antarctic continental slope and shelf regions during the winter months, which is outside the conventional areas of Argo autonomous floats and ship-based studies. Over 75,000 temperature and salinity profiles have been collected from 20–140 °E, between the Kerguelen archipelago and Prydz Bay Antarctica. These data offer invaluable new insights into the water masses, oceanographic processes and provides a vital tool for oceanographers seeking to advance our understanding of this key component of the global ocean climate. Here we present an overview of the IMOS database of hydrographic (i.e. temperature and salinity) profiles obtained by instrumented seals in the Southern Ocean. This database along with the MEOP- CTD database (Marine Mammals Exploring the Oceans Pole to Pole) currently includes more than 200,000 seal-derived hydrographic profiles with near circumpolar distribution and continues to grow.