Tuesday 15 January 2008 à 11:27

Position of Aurora Australis

Par Sophie Mouge. Correspondent aboard the Aurora Australis

FROM: Martin Riddle
DATE: 15/01/08
REPORT (SITREP) NO.: 330
UNIVERSAL TIME: 0100
LOCAL (SHIP) TIME: 1200
AUSTRALIAN EASTERN STANDARD TIME: 1200
POSITION: -66 24.4S, 139 47.6E
HEADING: Various
CURRENT SPEED (KNOTS): 0 kts
DISTANCE TO NEXT WAYPOINT (NAUTICAL MILES): n/a
DISTANCE COVERED LAST 24 HOURS (NAUTICAL MILES): 78.8 Nm
WEATHER CONDITIONS: Clear skies and good visibility, wispy high cloud, light wind 4 kts from 62T
AIR TEMPERATURE: 0.5
SEA TEMPERATURE: -1.2
SEA CONDITIONS: Calm seas, low E'ly swell 0.5 m
ICE CONDITIONS: Frequent icebergs, bergy bits and growlers, vessel running in clear water along edge of pack-ice.
REMARKS: Trying to sample the deep (1200 m) basin yesterday was very frustrating. Twice we had the cod-end of the trawl blow out and recovered only a very small haul retained by the coarser outer mesh. The trawl-mounted video camera provided only brief but tantalising glimpses of a sea-bed covered with large numbers of surface feeding sea-cucumbers between long periods of total darkness, caused when the trawl sank to its armpits in the fine diatomaceous ooze. After about 10 hours of trying we moved on to the next site at 800m on the basin slope and, while sampling, considered options for completing the deep basin. The 800m site was sampled in reasonable time, so we returned to the deep site and deployed the French beam with the intention of floating it briefly across the bottom. In the event the trawl was on the bottom for about 8 minutes and came up with a fine haul. The community was dominated by the large elasipodid sea-cucumbers seen on the video, looking very like fat little hippopotamuses grazing on the sea-bed, but included many other species including sea-stars (similar to Acodontaster and Cuenotaster), brittle stars (cf Astrotoma), stalked tunicates (cf Molgula), large gastropods, many small bivalves and several pelagic octopus. The night shift then took over and made up for lost time, completing 4 sites before retiring exhausted. We are well on track to meet our original sampling plan, having completed 91% of sites with 85% of time used. If the weather holds, we will have some time in hand when we have completed the original 67 sites and will use this to sample extra sites in transects over the shelf break to compare with those from the western sector.
Regards, Martin and Sarah.

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