May 9, 2001
Latitude: 68° 05 732 S
Longitude: 68° 37 667 W
Temperature: -0.3° C (31° F)
Wind Chill: -17.5° C (1° F)
Seas: 8 to 10 feet
Yesterday was a drastic change from the calm of Marguerite Bay. We ran into a low-pressure system and had gale-force winds and heavy seas. Winds gusted to 63 knots and seas ran up to 20 feet. Were approaching Station 41 and for the past three stations, because of the weather, weve deployed expendable CTDs, which are connected by wire to a computer and tossed over the side of the ship. They dont collect water samples like the CTD probe does, but they can be used in rough weather.
Great news. BIOMAPER II is back in the water! After working tirelessly over a period of 72 hours, the team has the fish back in the water. It was put in the water early yesterday morning before we hit rough weather.
Here are a few questions sent to us via e-mail:
Q: Are there any specific animals that live only in Antarctica? Judi
A: Adélie and emperor penguins; crabeater, Weddell, and Ross seals; and blue and snow petrels live only in Antarctica. Thanks to Ari Friedlaender and Chris Ribbic for their help on this one.
Q: When the krill live under the ice, do they still move with the Deep Scattering Layer? Veritas
A: No. The theory is that the larval and small krill do not migrate. They stay near the surface with the ice. The larger krill are thought to migrate within the water column. That diurnal migration is something that the research team here hopes to shed some light on.
Q: What type of clothing do the scientists wear to keep from freezing? Do you do all of your research within the ship? Anna
A: There are two things to remember to keep from freezing: Stay warm and stay dry. Layers of clothing under a waterproof and windproof outer layer work wonders.
Most of the research is conducted remotely from within the ship but a lot of time is also spent putting equipment into and out of the water. For these deployments, the science staff works closely with the marine technicians (MTs) and the ships crew, from the bridge to the winch operator.
The team working on the bird survey has a specially constructed observation box. It offers protection from the wind but not the cold.
Q: How does the ship get through the ice? Julian
A: The Palmer has a specially constructed bow which allows it to ride over the ice. The weight of the ship then causes the ice to break.
Q: Is seasickness a concern for the scientists on board? I know it is a large ship, but you must encounter some rough seas that keep you rockin S. Lajoie
A: We have indeed encountered some rough seas, but seasickness has not been too big of a concern for the scientists. Some have spent a day or two in the comfort of their cabin, especially during the gale we weathered, but there has not been a widespread problem.
Before the ship left port, there was a sign posted that read Seasickness is unpleasant; please take proper precautions. Most of us heeded the warning!
Q: I read that the thermal wave that encircles Antarctica has broken down into many hot/cold areas. Are there any forecasts onto how this will affect the lifecycle of the krill, considering the importance they will have on future food production for the planet and for other species? Paul
A: Scientist Eileen Hofmann answers: This is an interesting question and one that is the topic of current research studies. The Antarctic Circumpolar Wave produces regions of warmer and cooler conditions as it moves around the Antarctic. This in turn produces high and lows in the sea ice that is produced each winter in the Antarctic.
Thus, you can picture a bulge in the sea ice extent that moves around the Antarctic with some periodicity. It takes about four to six years for a given area of the Antarctic to go from a maximum to a minimum in sea ice extent. It just so happens that Antarctic krill are believed to live for four to five years. As a result, their life span is the same length as the time it takes to go from high to low conditions or vice versa.
Antarctic krill do better during times of high sea ice extent, presumably due to better food resources in the winter through feeding on food associated with sea ice. As a result, the summer following high sea ice is characterized by good spawning and eventually good recruitment to the Antarctic krill population.
The issue of concern now is that the time span between high and low sea ice may be increasing. If this happens then it is possible that Antarctic krill will not experience good conditions during a life time and this could lead to reduced recruitment to the population. This is one of the hypotheses that is being tested as part of the Southern Ocean GLOBEC program.
Thanks for all your e-mailskeep them coming!
Mark Christmas, nationalgeographic.com field producer
Have a question for Mark or the SeaLab team about the expedition or life at sea in Antarctica? In every dispatch, Mark will answer selected questions from readers.
[Note: nationalgeographic.com does not research or copyedit dispatches.]
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