This is the second report to NSF of the second broad-scale cruise of the U.S. Southern Ocean GLOBEC Program aboard the Research Vessel Ice Breaker Nathaniel B. Palmer. Since the first report, we have completed work at stations #19 to 48 (out of a total of 92 planned stations) and we are still averaging about three stations per day.
At these stations, we have completed 29 CTD profiles during which water samples have been collected at a variety of depths for nutrients, chlorophyll, O2, microzooplankton, krill experimental studies. Towing for phytoplankton, zooplankton, and micronekton has been done with a number of sampling systems including twenty phytoplankton ring net tows, seven 1-m2 MOCNESS tows, five 10-m2 MOCNESS trawls, nine vertical plummet net casts, and ten Tucker Trawl tows to capture live animals for experimental work. During the reporting period, three under-ice dives took place to collect krill for experimental work and to survey their distributions and five ROV deployments have been conducted to survey the distribution of zooplankton, especially krill under the ice. An experimental krill camera was deployed once. Over-the-side operations also included using the personnel basket to put investigators onto the ice for ice coring and ice collecting activities. This occurred on five occasions. The along track scientific observations were made by observers of birds and mammals mostly during the daylight periods between stations. Twenty-one sets of daytime bird observations and eight observations of marine mammals were made. In addition, night vision glasses have been used to make nighttime observations of birds on five occasions. These same observers have also been making ice observations and logging them. BIOMAPER-II was returned to service at station #21, although intermittent problems associated with damage caused by collisions of the towed body with large chunks of ice sweeping under the ship's hull caused some transits between stations to be missed while repairs were being made.
For the first half of the cruise, the ice conditions have only been a serious impediment to our movement between stations in the interior of Marguerite Bay. The N.B. Palmer was unable to get to station #39 on the eastern side of the Bay without undue time and effort, and this was also true for station #38. We elected to make observations several miles away from the intended locations and then move onto the more accessible stations. As work has progressed into the central portion of the survey grid, towing the nets and having ice in the ship's wake snag the wire has become increasingly common. Given the fairleads of the wire over the stern, this situation is unavoidable, but calls for increased vigilance. Weather has not been much of a problem. Although we have had a series of low pressure systems sweep over the area bringing high winds and snow, the absence of sea surface motion because of the sea ice has largely prevented the weather from affecting the work on station. Low visibility because of blowing snow has occasionally slowed or stopped the transits between stations for a time.
The around-the-clock sampling operation has gone smoothly due to the
excellent technical assistance we have been getting from the Raytheon support
group and the ship?s officers and crew. Beyond the normal tasks associated
with the along track and station work, they have been willing and able
to assist in the repairs to the some of the equipment that seem to be needed
on a regular basis. More detailed reports of the work taking place and
some of the results are being sent daily to the SO GLOBEC Web site: http://www.ccpo.odu.edu/Research/globec/cruises/cruise_menu.html.
Peter Wiebe, Chief Scientist