Measurement of ocean temperatures using instruments carried by Antarctic fur seals

The study aimed to test the utility of instruments deployed on marine mamma ls for measuring physical oceanographic variation and, using this method, t o examine temperature variation in the coastal waters around South Georgia. There was a significant correlation between temperature measurements made using a towed undulating oceanographic recorder (UOR) and concurrent measur ements from time-depth recorders (TDRs) fitted to lactating Antarctic fur s eals foraging from the coast of South Georgia, Congruence was found at hori zontal spatial scales from 0.01 degrees x 0.01 degrees to 0.5 degrees x 0.5 degrees (degrees of latitude and longitude), and at a vertical scale of 10 m. However, there was no significant correlation between temperature measu red by TDRs in the top 5 m and sea surface temperature (SST) measured by sa tellite remote sensing. TDR data provided information about temperature var iation vertically through the water column, and through rime. The UOR data were used to recalibrate the TDR data in order to correct for the slow resp onse time of the TDR thermistor relative to the speed of seal movements thr ough the water column. Seasonal temperature variation was apparent, and tem peratures also varied between regions, and with bathymetry. These results w ere consistent with the current interpretation of the coastal oceanography around South Georgia. In particular, the relationship between on- and off-s helf waters showed larger amounts of warmer surface water in a region in wh ich more run-off was to be expected. The study also showed that Antarctic f ur seals concentrate their activity in regions of colder, and presumably oc eanic, water. Such instrumented animals could provide near real time data f or assimilation into ocean models. (C) 2001 Elsevier Science B.V. All right s reserved.