LMG02-1A Weekly Cruise Report - February 17, 2002

The RV Laurence M. Gould (LMG) left Palmer Station Monday (2/11) and headed south to recover and redeploy WHOI and SIO moorings deployed in the study area last year on LMG01-03. With excellent weather and skilled personnel, the mooring work has proceeded quite smoothly, with seven of the eight SIO bio-acoustic bottom instruments recovered and five redeployed. With the exception of the S8 instrument, which was there but failed to surface after many release commands were sent, the other SIO instruments worked well, with most returning a full data set. Five of the six WHOI moorings were also recovered. The three WHOI moorings on the northern A-line returned with no noticeable damage. On the southern B-line roughly across the mouth of Marguerite Bay, the two southern most moorings B2 and B3 were recovered in patchy ice, with damage to the upper instruments due to passing icebergs. The B1 mooring did not respond to any acoustic commands, and a 6 x 6 nm acoustic search failed to locate the mooring. In addition, CTD casts have been made at the WHOI mooring sites, and XBTs taken at the SIO moorings. Two surface drifters and three isobar floats have been released.

Initial looks at the SIO and WHOI mooring data are very encouraging. The SIO moorings have recorded blue, fin, and humpback calls, plus capture the same blue whale call on several acoustic paths, which will allow tracking the whale's motion near the instrument. Blue whale calls are recorded year-round. The moored ADCP data shows relatively weak tidal currents (under 10 cm/s) with occasional stronger subtidal flows, especially present before the local onset of ice cover. The moored bottom pressure recorders also returned good data, with a clear tidal signal and some subtidal T/S variability. Both WHOI and SIO teams hope to download all their recovered instruments before reaching Punta Arenas.

In the next three days, we plan to deploy the three new WHOI moorings, seven floats, and several drifters. Then the LMG will head into Marguerite Bay and conduct intensive marine mammal work and deploy one SIO instrument until we need to head north to return to Palmer Station.

Bob Beardsley

Chief Scientist