Thursday 7 February 2008 à 11:28

Data for the Umitaka Maru

Par Graham Hosie (CEAMARC Leader) and Takashi Ishimaru (Voyage Leader)

Position of the icebreaker :
- Latitude : - 66° 23.9 S
- Longitude :140° 43.5 E
Current speed : 10 knots
Heading : 090

Distance in last 24 hours : 37 Nautical miles
Distance to next waypoint : 17 Nautical miles
Weather conditions : Clear and sunny, cloud low on N and W horizons, very good visibility to the horizon, wind 6 knots variable direction mainly from SSW.
Air temperature : - 5.1° C
Sea temperature : 0.6°C
Sea conditions : Smooth sea, low swell from SE, 1 m wave

On our last attempt to set anchors, we found reasonable ground and the wind eased allowing stable conditions for one more attempt at calibrating the echo-sounders. We were successful and the hydroacoustic team is happy. The sun also appeared for the first time for a few days and has remained with us. Once the calibration was complete, we headed back to the last station on the 140E longitude transect at 66 20S. This site was a deep basin of 500-800m in the continental shelf surrounded by ground of 200m depth. This site produced a Antarctic krill in deep trawls and ice krill in the surface waters. Numerous Antarctic herring (Pleuragramma) were caught in both the IYGPT and RMT nets. Smaller nets caught large amounts of diatom phytoplankton. The clear skies and light SE wind brought cold conditions of -5 deg C, making for a slippery icy deck and frozen nets. We are now travelling along the west-east transect (66 20S) towards Mertz Glacier and have already completed the next station on this line in 166m water depth. More Pleuragramma adults, juveniles and larvae were collected plus a number of ice fish juveniles. The French team are happy as they have collected specimens from each of the known year groups of Pleuragramma. Surprisingly, Antarctic krill dominated the trawls instead the ice krill. The zooplankton team are happy with more unique species of gelatinous zooplankton, some are likely to be new species. Overall, in the last 24 hours we have calibrated the echo- sounders, completed two stations and done six plankton net hauls, five IYGPT nets, eight RMT nets and two CTD casts.
Regards Graham and Takashi



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