27 October 2007

Photo: Crabeater seal triad: male, female and pup

We arrived at Peter I Island on 25th October at around midnight and stood off the island about 20 miles. The morning of the 26th was stunningly clear and brilliant. I was up just before dawn (~ 0430) and organized the plan for circumnavigating the island to get a general idea of what fauna was at or around it. The island (named by Bellingshausen in the early 1800s when he discovered it) is about 18 km long by 8 km long and covered by ice and snow. It is the tip of a massive volcano that rises straight up from the ocean floor with nothing around it for several hundred km. Moderately abundant flocks of snow petrels, southern fulmars, and Antarctic petrels were off the east side....they breed on the island though it is difficult to see where they might find the bits of bare volcanic rock they need as so little of the island is free of snow and ice. We saw a few leopard seals and crabeater seals and minke whales in the surrounding pack ice.

We departed the island at 1430hrs and headed straight for the Drake Passage en route to Punta Arenas, Chile. A substantial new ice field had formed that extended north quite a ways so we did not exit the pack ice until this morning (27th) at 0530. About the same time of day on the same date in 1915, Ernest Shacketon and his crew abandoned their ship (the Endurance) when it finally was completely crushed and sank within hours after being trapped in the pack ice of the Weddell Sea. The history of his leadership and survival of all aboard is one of those remarkable stories of polar lore. We left the pack ice while most were sleeping and unaware of the change except for the building ocean swell that comes without the protection of the pack.Conditions have been moderate today in mostly side-following seas and winds.I've continued my observation duty in the ice tower for surveys of seabirds and marine mammals, stopping only during our weekly fire drill just after lunch. Marine mammal and seabird diversity and numbers have been low since leaving the pack ice, with just a few cape petrels, Antarctic petrels, blue petrels, southern fulmars and a very occasional giant petrel. Things should pick up tomorrow morning as we approach the Antarctic Convergence. Our expected arrival at Punta Arenas is the afternoon of October 31st and I think I'll be flying toward home on 1 November, though we haven't got travel itineraries yet and likely won't until Monday or Tuesday. bs

The map below shows the drift on Ice Station Belgica from September 27 through October 24. The overall distance drifted was around 240 nautical miles.

October 21

Photo: Dr. Brent Stewart (HSWRI, left) and Dr. Jean-Louis Tisson (head of the Belgian science team) sign out aboard the RVIB Palmer prior to leaving the ship for on-ice research activities.

The last two days we have had fairly obnoxious weather with huge NE winds and blowing snow, obscuring visibility. We've been 'drifting' SW with the floe at about 0.5 to 0.8 knots and are now at 70S,93.5W--back to where we were about a week or more ago.

Winds died this morning a bit and blowing snow was down to just the area within 1-2 feet of the surface so it was safe for some limited on-ice operations. I'm planning to help the geophysics team with re-measuring a few 300m lines for snow depth and ice thickness in the a.m. and then will go over to the Patria site to check on the crabeater seal triad (male, female, pup) in the afternoon. I've been spending virtually all day in the ice tower. Lots to see as we approach the continental shelf including at least one minke whale, several giant petrels, some Antarctic and snow petrels, one slender-billed prion, and now about eight crabeater seal breeding pairs within 3-4 mile radius of the ship,including at least three with pups. The pair nearest the ship (Danco site) have now been hauled out continuously for 16 days and no pup so I'm thinking that the female is not pregnant and am considering other reasons for this long-fasting haul out.

A female leopard seal that appears to be pregnant hauled out about 600 m from the ship early yesterday and slept all day until just about sunset (2200 hrs) and then went back into the water...just about the time that most crabeater seals are in the water and beginning to feed. I'm hoping that she hauls out again tomorrow closer to the ship and stays around for a few days. bs

October 12

I led a Zodiac science operation today (the first one of the cruise and my first solo Science Event of the cruise) - took the boat out about a mile to a second breeding pair of crabeater seals (another pregnant female and attending male have hauled out very near the icebreaker). No pups yet, but we should have a birth from one of the females within the next day or two. High pressure, light winds, and blue sky today (ambient temperature is -11.7C). Peter I Island is in complete view (about 50-60 miles away) - spectacular! bs

October 8

Worked on the ice yesterday helpling to survey ice thicknesses (measurements every meter for 300 meters on two 300-m lines). Temps have been around -12 to-15C with wind chill at about -40C and blowing snow periodically to obscure. But we got it done.

The pregnant female crabeater seal near the ship has not pupped yet but may today (it's 4th day she has hauled out) so I'm sticking in the ice tower onboard the ship for the day to try to catch the birth on film. Other projects seem to be going well. We are still drifting to the north and are now just north of 70S at 93W. Southwest winds continuing strong this a.m. -bs

First Monday in October (aka, the Supremes back on stage)

Weather has been a bit hoary but we worked on our big ice floe station for a few hours yesterday. We're going out again this morning, hopefully for most of the day. Winds are down to about 25 knots and the temperature is around -10C, with a wind-chill of -35C. We are now at 70deg24min south, 94deg07min west (i.e., just off eastern end of Thurston Island in the western Bellingshausen Sea).

We are drifting (really cruising) at about 0.6 knot to 1 knot westward, and should enter the eastern Amundsen Sea perhaps by the end of the week. We hadn't planned on going there after the delays because of the fire, but it now looks like we'll get to spend some time there anyway.
Yesterday, some emperors and one Adelie penguin investigated us and we saw a minke whale in a narrow lead between two floes last night. There will likely will be some seals out today if it warms a bit more. -bs

September 27

We made little headway today after finishing Ice Station III at about 0700hrs and then pushing south. But we did find a large floe to park at for the next couple of weeks and docked next to it tonight at about 1830hrs. It is at about 70deg41.1min south, 090deg59.15min west....and we are free drifting to the west at a fair rate. We should have a better idea tomorrow about our exact drift rate.

Tomorrow, the 'colonization' of the giant floe begins - and drilling and shoveling and ice-mass-balancing will get into full gear. -bs

September 25

We arrived near Peter I Oy (Peter the First Island) in pretty miserable weather Monday night around 11:00 p.m. We then started heading due south to the ice which we penetrated sometime early Tuesday morning. I was in the ice tower early and started seeing lots of crabeater seals almost immediately. Later "lots" turned to huge numbers scattered all over the congested ice. We also saw leopard seals, though less abundant, a Ross seal, minke whales, killer whales, Adelie penguins and scattered emperor penguins...a very interesting area here.

We stopped for our first ice station at around 1430hrs and had about 15 people out on the ice in two parties. I was designated leader of the ice geophysics party...so I'm hoping to get an "Ice geophysics" certificate at the end of this trip. We'll do some CTD (conductivity, temperature, depth) casts and other oceanographic sampling as well as an ROV (remotely-operated vehicle) deployment in just a bit. We then head south again for about 5.5 hours where we will do another ice station at around midnight, and then repeat every 5.5 hours for two more days before getting to first big floe processing station. More later.... Brent

Greetings from Palmer Station!

We made an unscheduled stop on the Antarctic peninsula following a fire aboard ship a couple of days ago. No one was injured but the fire (on the main deck) was serious enough that two labs are now sealed for the remainder of the cruise - some items melted and others were damaged by heat and soot. Several days after cleaning, most of the thick soot is gone from the main deck though it still drifts slowly out of the ventilation ducts. We are planning to continue the cruise - most of the instruments appear to be functioning or substitutes have been found. But the e-mail servers are down on the ship, as are the instruments for making measurements while underway - it's not clear whether those can be brought back up. We hope to make up for lost time by cutting back on some en route activities so we can get into the ice as far as possible as quickly as possible - to about 72 degrees S latitude along 105 W longitude. I've been conducting surveys for marine mammals and seabirds throughout the cruise from the ice tower - we have about 10 hours of daylight. Bird densities are very low, but I've recorded about a dozen different species so far. Lots of marine mammal sightings near Palmer Station, including crabeater seals, minke whales and adult male Antarctic fur seals. bs

First Stop, Santiago, Chile

Departing San Diego is always difficult because it means leaving America´s Finest City and the best climate just about anywhere...especially when expecting a temperature shift from the comfortable 80 degrees F at Mission Bay to the late winter sub-sub-sub-freezing temperatures of the Antarctic. I arrived in Santiago, Chile early morning on 31st August to typical sister city weather and was met by the terrific NSF representatives at AGUNSA who shuffled me through passport control and onto their office for coffee and snacks. Departure to Punta Arenas in a couple of hours and then will join the rest of the crew and research team, led by the principal investigator Steve Ackley, on the NSF Icebreaker Nathaniel B. Palmer this afternoon. Some last minute efforts to get some supplies and equipment to the ship with me were partly successful. A few valves and filters for scientific equipment reached San Diego by Federal Express about a half hour before I struck off for the airport in San Diego. Some other supplies and chemical stains got delayed when the Federal Express plane that they were scheduled on broke down. We are hoping that they may be quickly redirected to Punta Arenas in time to reach the ship before departure. More from Punta Arenas. Hasta pronto. -bs

SIMBA (Sea Ice Mass Balance in the Antarctic) Expedition 2007

Dr. Brent Stewart holds a Weddell seal pup on the sea ice in McMurdo Sound, Antarctica. Weddell seals are one of four species of ice seals Dr. Stewart will be studying during the SIMBA (Sea Ice Mass Balance in the Antarctic) expedition aboard the icebreaker RVIB Nathanial B. Palmer (see photo below) cruise, one of several international research efforts being conducted under the auspices of the International Polar Year. Scientists participating in the SIMBA cruise are also likely to observe leopard, crabeater and Ross seals and a variety of species of whales and seabirds.

For more information on the SIMBA expedition, go to http://www.utsa.edu/lrsg/Antarctica/SIMBA/objectives.htm. A brief project description from that website follows: The quantification of Antarctic sea ice thickness on a circumpolar quantitative basis will provide, for the first time, a fully quantitative baseline data set for monitoring of future change in the Antarctic sea ice cover. Using the coupling between thickness, physical property and remote sensing measurements, a full validation of altimetry (for ice thickness), and passive and active radar (for thin and thick ice characterization) will enable future monitoring to rely more on remote sensing than costly and regionally limited field surveys. Ice thickness is the principal quantitative measure of ocean-atmosphere exchanges and the data sets will therefore be the gold standard for validation of air-ice-ocean coupled models, and thereby increase confidence in their capability for future prediction. Sea ice mass balance determines salt and freshwater fluxes to the ocean, and therefore contributes directly to the formation of water masses and oceanic circulation characteristics in polar regions. Understanding the coupling between ice physics, biology and biogeochemistry will determine the direction and magnitude of gas fluxes and sediment contributions from sea ice derived fluxes. The role of ice-covered oceans in present day and past exchanges (as determined from continental ice core measurements) and relation to climate change will be better correlated and quantified.

Dr. Stewart and the research team will set sail for Antarctica on Thursday, August 30. The icebreaker will be departing from, and returning to, Punta Arenas, Chile. Please be sure to check in regularly to keep up to date on Dr. Stewart's research activities.

International Polar Year

The International Polar Year (IPY), which begins in March 2007 and continues until 2009, is a program of international research and education focused on the Arctic and Antarctic regions. For more information on IPY, go to http://www.us-ipy.gov/.