|Blue skies, calm seas, and sunshine are a welcome sight after several days of heavy seas and snow.
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Photograph by Mark Christmas
May 1, 2001
Latitude: 66° 06 639 S
Longitude: 70° 53 106 W
Temperature: -1.0° C (30° F)
Wind Chill: -17.1° C (1.2° F)
Seas: 2 to 6 feet
Were on Station 10. Theres a raging snowstorm outside. Its 0300 hours. A CTD has just been recovered and MOCNESS is about to be deployed. It takes total concentration and an awareness of your surroundings to work safely in these conditions. The boat is heaving and awash with waves. Ice and snow are on the decks. There are cables under tension. MOCNESS goes in without a hitch.
The morning brings blue skies with clouds on the horizon. This should be a good day for bird and whale observations. BIOMAPER is back in the water. There have been a whole lot of solutions to be worked out. The team is hoping that things will run smoothly now.
A single humpback is sighted off the starboard bow. Catherine Berchok of Penn State University gets the word and rushes to deploy a sonobuoy so she can listen for its call. So far, only the sound of the ships engines. Ill recap the sightings and soundings tomorrow.
I have received many e-mails from people around the world who are following our expedition on nationalgeographic.com. Here are a few:
Q: I was reading about the extreme temperatures, and I would like to know, how do you possibly stay warm? Julie
A: The temperature range on the continent and on the water differ greatly. The extreme cold temperatures of the mainland are severe. You must remember that the freezing temperature of seawater is just about 28° Fand were not even in the ice yet. If you look at the temperatures on some of the dispatches, youll see that its mild compared to the temperatures at the South Pole Station, which can reach -90° F and below. Two of the keys are to stay dry and wear layers.
Q: Does the ozone hole that opens up periodically over Antarctica have any effect on the krill population? Gary
A: According to the scientists onboard the Palmer, the effects of the ozone hole on the krill population is indirect. The effects of ultraviolet (UV) radiation directly on krill is minimized as the UV radiation is contained to the upper levels of the water columnabove the area in which krill are usually found. The phytoplankton on which krill feed however, are affected.
There also is a global warming link to the cycle of sea-ice formation. It has been observed that in the summer following peak sea-ice formation there is a bloom in krill production. This peak sea-ice cycle had historically been determined to be six years in duration. There is evidence that this cycle is now an eight-year event.
If you consider that the lifespan of an Adelie penguin is believed to be 12 to 14 years, the penguin would enjoy two krill blooms in its lifetime with a six-year sea-ice cycle. If the environmental frequency of sea-ice formation changes, it is almost certain to have an effect on the biological frequency of the penguin, which would in turn affect the krill as there is a shift out of equilibrium.
Remember, if you have a question, drop us a line!
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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