Weekly Science Report 1: LMG01-06 Southern Ocean GLOBEC

Cruise days 21 July to 1 August inclusive
Science days 27 July to 1 August inclusive

I. LMG 01-06

a. Mission statement:
Overall goal is to elucidate shelf circulation processes and their effect on sea ice formation and Antarctic krill distribution, and to examine the factors that govern krill survivorship and availability to higher trophic levels, including seals, penguins, and whales.

b. Projects represented on the process cruise
BG-232-0 Costa/Burns/Crocker - Foraging Ecology of Crabeater seals
BG-234-0 Fraser - Winter Foraging Ecology of Adélie penguins
BG-235-0 Fritsen - Sea Ice Microbial Communities
BG-237-0 Harvey- Biochemical Determination of Age and Dietary History in the Krill Euphasia superba
OG-241-0 Smith/Martinson/Perovich Optical Environment of the Western Antarctic Peninsula Region
BG-244-0 Quetin/Ross- Winter Ecology of Larval Krill: Quantifying their interaction with the Pack Ice habitat

c. Cruise overview to date
22 July. After considerable last minute preparations, the LMG departed on time from Punta Arenas at approximately 17:55 LT on 21 July 2001 to begin the US SO-GLOBEC Process II cruise.  Almost all of our gear and personnel made it safely to PA. Unfortunately, a shipment of lithium batteries for the Martinson/Perovich/Smith program was held up on the Argentine border by a trucking strike. However, Bruce Elder was able to come up with a workaround so they are set to go. Unfortunately one of the two Raytheon Electronics Technicians was not able to make the cruise. Moreover, our lone ET Peter Martin has been doing an outstanding job! Once under way we enjoyed good weather and calm seas as we approached the Strait of La Maire and the entrance to Drake Passage.

23 July. The LMG continued across the Drake towards Palmer Station via the inside passage route.  We did not conduct a XBT transect during this cruise.  We exited the sheltered waters of the Straits of Magellan and the east coast of Tierra del Fuego, and encountered significantly more ship motion than previously experienced in the sheltered waters of the straits or in the lee of Tierra del Fuego.

24 July. The LMG continued across the Drake, which treated us reasonably well, though with a fair bit of rolling quite a bit due to beam seas.  While en route Karl Newyear deployed two NOAA Technoccean global drifters. The LMG crossed 60o S latitude earlier this morning, and this afternoon we sighted first ice.  There were loose bands of heavily decayed brash ice near 62° 10' S.  We initiated daily radio comms between the LMG and both Palmer Station and the NBP.

25 July. The southbound transit of the Drake passage was largely uneventful.  Our route took us along the inside passage through the Gerlache Strait and the Neumayer Channel, though foggy conditions prevented much sightseeing.  Although we were within sight of Palmer Station at approximately 17:00 LT, it took almost an hour to reach the dock as the dock was heavily covered with ice. After considerable effort Captain Verret skillfully maneuvered the LMG to the dock. We spent the evening enriching the Palmer Store with cash and enjoyed the Station's warm hospitality.

26 July. Cargo offload began at first light (08:30 LT) and continued well into the afternoon. Various science groups took advantage of the facilities a Palmer Station for science prep. Many individuals enjoyed the walk up the glacier behind Palmer station. The LMG departed Palmer Station at approximately 16:25 and began steaming towards GLOBEC process site #1.

27 July. Our progress was slowed considerably by pack ice of varying thickness and concentration with several icebergs visible.

28 July. The LMG arrived at GLOBEC Process Site #1 early this morning through relatively heavy ice but without requiring assistance from the NBP, which was nearby.  The ice conditions prevented us from using the 1-m MOCNESS so we waited until just before first light to conduct a CTD cast then proceeded with scuba diving and ice coring operations.  The day was concluded with another CTD cast.

29 July. Today we proved that the LMG could penetrate the pack ice off of Adelaide Island under its own power in winter as we crossed the Antarctic Circle.  Early this morning we made a rendezvous with the NBP and exchanged some equipment via zodiac.  Science activities today included seal tagging, diving, our first MOCNESS tow, and a CTD cast.  This area appears to be a biological hot spot that we considered using for GLOBEC Process Site #2.  Fog throughout the day coated everything with a thick layer of delicate rime.

30 July. The LMG continued to occupy GLOBEC Process Site #2.  We were very successful in gathering samples today despite deteriorating weather.  An ice party spent most of the day off the ship on a large floe, the sealers delighted in collecting scat samples, and the krill teams deployed some 1-m plankton nets as the ship drifted at ~0.7 kn in high winds.  The first Adélie penguin of the trip was netted, tagged, and released, later that evening we caught and deployed an additional 5 satellite tags on Adélie penguins.  We carried out a 1-m MOCNESS tow later that evening.

31 July. The LMG has had a rather slow science day, with most of the time spent in transit from a rich biological site that was occupied for only one day towards Process Site #2 proper.  We were able to tag a total of 6 Adélie penguins yesterday prior to moving off the southwest coast of Adelaide Island.  We had a reality check today, as Captain Verret has been able to maneuver the LMG through a wide variety of ice conditions. However, the ice conditions finally caught up with, as we could not make further progress due to ice pressure. We notified the NBP that we would probably need their assistance to get out. After only two hours the Captain Verret was able to free the LMG from the pack ice and we were underway under our own power. We then proceeded back to the open waters directly south of Adelaide Isld,

1 August. We traveled along the pack ice edge in a localized polynya southeast of Adelaide Island in northern Marguerite Bay.  We have seen very few seals but the weather has improved markedly.  Our next planned rendezvous with the NBP will occur in 2-3 days near GLOBEC Survey Site #28.  Meanwhile we will work the southern Adelaide Island area. We carried out a XBT transect and a 1m MOCNESS tow across the polynya in the northern region of Marguerite Bay. We spent the afternoon looking for seals. We succeeded in spotting two leopard seals and 2 crabeater seals. An attempt was made to place a satellite tag on one of the crabeater seals, but it retreated into the water before the animal could be captured. As dusk set in the ice teams began sampling the ice. This will be followed with a CTD cast. The next day or two will be spent looking for predators in the vicinity of Adelaide Island. After this we plan to get the assistance of the NBP to take us to Process site 2 that is further into the mouth of Marguerite Bay. Once there we hope to deploy a complex ice drifting buoy and set up a multiple day process station.

d. Individual group reports

BG 232 Costa, Burns and Crocker. Our research focuses on how crabeater seals forage within the seasonal winter pack ice. Data on Krill distribution and abundance acquired as part of the Southern Ocean GLOBEC and the biophysical coupling will provide a context to place the foraging behavior of crabeater seals. Satellite linked time depth recorders are being placed on the seals to monitor their foraging patterns (locations and dive patterns). Our field team on this cruise consists of Dan Costa (U. C. Santa Cruz), Nick Gales (Australian Antarctic Division), Steve Trumble (Univ of Alaska), and Brigette McDonald (Sonoma State University). Fortunately we have the able assistance of Steve Trumble who was part of the previous crabeater field team on the April-May GLOBEC cruise. During the first few days of the cruise we saw very few seals either in the water or hauled out on floes. Although, this lack of sightings is frustrating, we are buoyed by the daily location updates we are receiving from tags placed on 8 seals during the earlier GLOBEC cruise. These animals are now diving very deeply, with a new maximum depth for the species of 605 m! Our first significant seal sightings occurred as we were in transit to process station 2. At mid day we located a crabeater that was sound asleep on a medium sized floe. Captain Verret was able to edge the LMG right up to the floe where we were lowered onto the floe with the personnel basket. We then succeeded in anesthetizing the seal and placing a satellite linked time dive recorder on it. Although there was little wind (less than 5 kts) it was very cold -12°C. The cold made processing samples difficult and we were not able to measure blood volume, as the material we inject into the animal froze before we could administer it. We had some things to learn about working in such cold weather, but for a first seal things went very well. We were able to obtain a complete set of morphometric measurements (body mass, blubber thickness, length, girth), and we collected blood and other tissue samples. We are glad to report that the satellite tag is working well and the animal is now along the outer coast of Adelaide heading north. The ship then proceeded south towards Process site 2 and along the way encountered over 200 crabeater seals hauled out along a large lead running along the coast of Adelaide Island. We decided to stay here for the night, to allow seal tagging the next day in daylight. Unfortunately the weather deteriorated the next day, although it was warmer (-2°) the wind was very strong coming out of the N NE 30-40 kts gusting to 50. We found that under these conditions the seals prefer to stay in the water, as we saw many of them around, but they refused to haul out. We were able to collect 4 scat samples from the area were the seals hauled out and although the material was very digested the only prey item found was krill. Given that we will have to wait until the NBP can escort us into Process Site 2, we were able to use much of 1 August to search for seals. We went looking for pack ice in the Southern tip of Adelaide Island, but found that the recent wind had created a rather large polynya in the Northern Reaches of Marguerite Bay. We searched across to Porquois Pas Island and spotted 2 leopard seals and 2 crabeater seals. The first crabeater seal was on a small floe and it went into the water when we approached, we attempted to capture the second crabeater seal but it managed to escape during our attempts to capture it. We are now returning the to area where we saw so many seals the other day in hopes that they will now haul out given the better weather.

BG 234 Fraser.  It is estimated that about 250,000 Adélie penguins winter on the sea ice of the WAP.  The key objective of our study is to understand the processes the sustain such a large predator population during the polar winter.  This work relies on the use of ARGOS-based satellite transmitters (PTTs) to determine the distribution and movements of Adélie penguins relative to features such as such as bathymetry and sea ice.  We are also obtaining samples of their diets to understand winter foraging ecology.  Our field team consists of Bill Fraser and Steve Muth.  Similar to seals, penguin numbers increased as we moved from the northern to the southern reaches of the study grid.  To date our group has had one very successful day.  On July 30 we encountered several groups of AdJ lies off the southern end of Adelaide Island and a single bird was caught and instrumented with a PTT during the afternoon.  Later that day a larger group of AdJ lies was encountered near Cone Island and a 5 person team was lowered onto to ice with the personnel basket to help capture the group. Five birds were subsequently caught and instrumented with PTTs.  We are pleased to report that all 6 of the instrumented birds are transmitting locations.  Most interesting, is that all these birds are currently working an ice edge west of Adelaide Island and focusing their foraging activities over the 200-500 m contours.  This area also held large numbers of crabeater seals, suggesting it may be an important local foraging area for upper-trophic level predators.

BG 235 Fritsen. In conjunction with BG-241 and BG-244, we are implementing our program to record the distribution and activity of sea ice microbial communities within the predominant ice types within the region and how these are influenced by the ocean-atmosphere interactions.  This program consists of recording the ice types encountered in transit, characterizing the ice at process stations occupied, and contributing to CTD/ XBT operations for vertical profiles of the water column. Ship-based hourly ice observations (using ASPeCT protocol), direct ice sampling at stations, and sampling of the rosette are daily activities.  Ice types sampled at process station one included flat, first year ice; forming frazil / grease ice; deformed first year ice; and gray ice between first year floes. Our field team consists of Chris Fritsen, Sarah Marschall and Jeramie Memmott. At station two, nilas ice, flat first year ice, and deformed first year ice were sampled. Thus far, our combined efforts have resulted in sampling a total of 20 ice cores from floes having thicknesses ranging from 10 cm to 2.0 meters (predominant ice floe thickness = 30-50 cm).  Ice, snow, and water column samples are analyzed for microbial biomass (as particulate carbon and nitrogen, chlorophyll a, and bacterial biomass).  Samples are also analyzed for salinity/nutrient ratios to determine if the ice nutrients are indicative of net production or loss of microbial biomass.  Photophysiology and bacterial production experiments have been conducted on a subset of samples collected thus far.

BG- 237 Harvey. The major focus of this project is the biochemical determination of age structure in E. superba and lipid biomarkers indicative of its dietary history. Initial MOCNESS tows were unsuccessful in collecting adults, although larval animals were collected and divers made others available for analysis after collection. Additional larval samples collected by the NBP were also made available and transferred during a planned rendezvous. A MOCNESS tow on 7/31 south of Adelaide Island collected a minimal number of adults and other size classes to allow sorting and dissection of eye stalks for onboard analysis of age markers. Additional tows are planned to provide adequate numbers for statistical analysis. The construction of the portable HPLC system for this project presented the opportunity for separation and analysis of pigment distributions. Ice cores, slushes and surface waters have been collected by other project teams for pigment analysis during the cruise. Pigment distributions in these samples will allow comparisons with direct microscopic observations and primary production measures being conducted on parallel samples by other project teams. Our field team consists of Rodger Harvey and Se-Jong Ju.

BG-244 Quetin/Ross BG-244-O. Our field team consists of C. Boch, T. Newberger, L. Quetin, S. Oakes, M. Thimgan, and J. Watson. All went well with the checkout dives at Palmer Station on July 26.  We used the dive locker to save time and avoid the offload, and dove near the seawater intake.  We noted that the steel sheathing on the line closest to Gamage Point has a separation of about 4 feet in the inter-tidal zone, exposing the plastic pipe to damage from ice.  We also used the time at Palmer Station to do some weighing of chemicals.  Our visit went extremely well thanks to the great reception at the station.  Thanks, Palmer.

We were able to dive in the pack ice July 28, 29 before weather shut us down.  We were able to collect krill larvae on both dives and have started 2 instantaneous growth rate (IGR) experiments and are maintaining larval stocks for feeding experiments.  Mid-shelf (66° 22.5, 70° 44.7) the larvae were less abundant under the ice than near Adelaide Island (67° 13.7, 69°  25.5).  We have yet to measure the IGR experiments.  The intermolt period for larvae from LIGR 1 was 26 days.  LIGR 2 is still running.  Though we have found stages ranging from Furcila 4 through Juvenile, most of the larvae are in the Furcilia 6 stage.

OG-241-0 Smith/Martinson/Perovich. Our field team consists of Bruce Elder, Sharon Stammerjohn and Kerry Claffey. Ice studies performed on 3 different ice floes. This constitutes 59 meters of ice drilled for ice thickness profiles.  Also measured were snow depths and snow-ice interface temperatures.  The ice thicknesses of the level portions of each floe were 55cm, 32cm and 35cm in that order. 2 of the floes contained rafting, ridging and on the last floe the surface was flooded. Hourly ice observations performed over 577 km using the ASPECT protocol.  20 cores obtained in conjunction with biology groups from 4 locations. Analysis of temperature, salinity and D18O profiles of each ice site. Ice buoys and instrumentation tested and ready for deployment.

Submitted by:

Daniel Costa
Chief Scientist

Karl Newyear
Marine Projects Coordinator