26 May 2001
N.B. Palmer

A second Automated Weather Station installation was slated for this day (27 May 2001) and thus we are located within ½ mile of Dismal Island in the Faure Island group. Our position is -68 05.494°S; -68 48.65°W (1005 local). These islands are in the northern end of Marguerite Bay. Winds are in the 18 to 22 kt range out of the north northeast (020). It is cloudy with off again/on again light snow. Dismal Island was first charted in 1909 by Charcot and named in 1949 because of its desolateness and loneliness. Today it fits that description.

The weather yesterday (26 May) was in contrast to today's. In the early morning, the winds were still around 30 kts during a MOCNESS tow that was completed at Survey Station 44 to fill in a gap in the sampling that resulted from bad weather forcing the cancellation of the tow during the survey. The winds, however, died down by 0900 and they remained in the 15 to 20 kt range during the survey of the bathymetry around the B-line of oceanographic moorings spanning the canyon in the outer portion of Marguerite Bay. Throughout the day, there were high clouds and the visibility was good. The air temperature in the early morning was one of the coldest recorded on this cruise at -6.5°C.

Eileen Hofmann reports that the activities during the day were focused on obtaining BIOMAPER-II data in areas that were missed during the survey and on obtaining SeaBeam measurements around the three current meter moorings that were deployed across the mouth of Marguerite Bay. The CTD was not deployed during these activities. However, the CTD group did thirteen XBT drops while the other activities were taking place. These were done primarily in the areas that were not included in the survey in order to increase the resolution in the temperature field and to determine the extent of change in the distribution in the one month since it was initially measured.

The vertical temperature profiles from the XBT drops show the same basic temperature distribution below 200 m as was observed during the first part of the survey. The only change is an on-shelf movement of the 1.5°C isotherm, which suggests that the bottom intrusion may have strengthened somewhat over the past month.

The largest difference between the recent and past temperature distributions is the cooling of the surface waters and the erosion of the Winter Water layer. In some places the Winter Water layer is completely gone and the upper water column is becoming homogenous down to about 80 m to 100 m. Surface temperatures are now negative (about -0.9 to -1.0°C) but are still too warm for ice formation.

Ari Friedlander reported that on 26 May sighting conditions were good during daylight hours. A moderate swell prevailed, as did light winds and partly cloudy skies. The ship was in transit in Marguerite Bay doing transects and observations were made from 1030 local until 1450 local time. No whales were seen during the day, although humpback whales were heard faintly from sonobuoys.

Catherine Berchok reports that on 26 May she deployed two difar sonobuoys. The first was halfway in between mooring B3 and B2. Humpbacks were heard in the medium loudness range and the sounds appeared to be coming from the direction of Alexander Island. The second sonobuoy was released 7.7 nm from B1 when the ship was past the danger zone for getting it tangled in the B2 mooring. By that time the signal had been lost on the first buoy.

A very noisy band of interference similar to that on the picked up on 23 May, except it is lower in frequency and is not related to the receiver channel. As a result, recording time was reduced to four hours.

BIOMAPER-II/MOCNESS report (P. Wiebe, C. Ashjian, S. Gallager and C. Davis):
Following the end of the mooring survey around 1830, a quick steam brought us to the position of Survey Station 27. This location was where the echosounder had failed a couple of weeks earlier. BIOMAPER-II went into the water about 1930, but once in the water, however, one of the VPR cameras showed up as not adjusted properly. So the towed body was brought back on board to adjust the camera. After the second launch, the towyo trackline went on a course from the vicinity of grid survey station 27 to station 28 and then over to station 31, a distance of about 50 nm. There was a turn back towards the Faure Islands before having to get the towed body back on board around 0700 to make the steam over to the Islands. The bathymetry along the transect line was extremely variable ranging from 700 meters to 140 meters. This made it impossible to towyo deeper than about 200 meters. The volume backscattering along the entire transect line was low and no substantial krill patches were observed.

A MOCNESS tow was made early on the 26th of May at the location of survey Station 44. Winds during this night were in the 25 to 30 kt range, but they did not interfere with the tow, which went to 350 m. Larval krill abundance increased with depth with greatest abundances in the 25-50 m depth interval, but below 100 m larval krill were sparse and there were very few post-larval krill. Pteropods and jelly fish were also present in the upper 100 m. Copepods and Chaetognaths were noted below 100 m as was a 2.5 cm fish in the 350-300 m depth range.

Cheers, Peter