July 10 - 2005 Options

[Betty_Carvellas]

July 10 - 2005

So far, the weather has remained sunny and clear. While on deck today, I was excited to see porpoises alongside the ship. On last year's cruise, we were in fog for the majority of the trip, and I missed the opportunity to see the wildlife. For now, I'm three for three, with a bald eagle in Kodiak on Friday, orcas yesterday, and porpoises today. It makes me sad to realize how quickly this environment is changing, and no one can really predict the impact on the organisms in this unique ecosystem. Today I found another newspaper, The San Francisco Chronicle, from July 8 in the lounge. The headline of one article read "Polar ice melting earlier, imperiling polar bears, panel says." Because the pack ice along the western coast of Hudson Bay, Canada, is melting 3 weeks earlier than it did 30 years ago, the polar bears are losing 3 weeks of feeding time during a peak period when they need to put on fat in order to live on shore during the summer months. On average, polar bears in that area weigh 15% less than they did 30 years ago.

I heard of another indication of the changing climate while talking today with Dr. Lee Cooper of the University of Tennessee, Knoxville. Lee's work took him on the USCGC Healy summer SBI (Shelf Basin Interactions) cruises of 2002 (when I was on board as well) and 2004. During the 2002 cruise, we ran into ice only three days out of Nome, Alaska, and we were unable to complete a line of stations east of Barrow due to heavy ice. Last summer, when the ship was on the same cruise path, it encountered almost no ice during the entire trip.

Finding explanations for climate change is not an easy task. Lee's work on the SBI cruises and on this cruise involves collecting water to analyze for oxygen 18, an isotope (different form of the same element, this one with 2 extra neutrons) of oxygen. By analyzing the ratio between oxygen 18 and oxygen 16 (the most common isotope), Lee can track the source of the fresh water component of the water he is sampling. As the Japanese current, Kuriosho, comes across the Pacific, it splits upon reaching the coast of North America. It heads south to California and north to become the Alaskan current that runs along the southern coast of Alaska and the Aleutian Islands. As it reaches the passes through the Aleutians, the current turns north into the Bering Sea. We're now sampling just south of Unimak Pass, the first pass where Pacific water freely flows from the Pacific into the Bering Sea. Lee should be able to tell, in general terms, if the components of the fresh water are from Japan or from the rivers, glaciers, and melting snow of Alaska or both. The farther north, the colder the temperature, and the higher the altitude at which the precipitation fell, the more depleted the oxygen 18. His data can help determine the amount of fresh water from Alaska, such as from melting glaciers, and therefore provide indications of global warming.



At our science talk this evening, Bon van Hardenburg, chief scientist, and Jackie Grebmeier, co-chief scientist, presented an outline of the work of the cruise. You can check the cruise map pictured below to see where we're headed; in future journals, I'll fill you in on all the science that you see listed.