HLY1502 letter 01 from Jim Swift

Sunday, 09 August 2015, 1:30 pm, local date and time (2130 UTC)

53.6°N, 166.5°W (Dutch Harbor, AK)

air 11.3 degC / 52 degF

water 13.5 degC / 56 degF

wind 12 knots from SW

leaving port, heading north to the Arctic Ocean

Dear Family, Friends, and Colleagues,

A half hour ago, the US Coast Guard science icebreaker Healy left the Aleutian Islands port of Dutch Harbor, Alaska, bound for the Arctic Ocean. 51 members of the science team, approximately 90 Coast Guard officers and crew, and shore support personnel worked diligently the past four days to ready the laboratories, deck work areas, science holds, and other areas for a long- planned NSF-funded (principally) 65-day voyage to study the geochemistry of the Arctic Ocean, not to mention filling huge stores of fuel and topping off tanks holding approximately one million gallons of fuel.

Wikipedia notes that Dutch Harbor was “one of the few sites, besides the attack on Pearl Harbor in Hawaii, in American territory to be bombed by the Japanese during World War II”. There are ruin-like remains all around from the war-era military facilities which involved over 20,000 personnel. Today the town is one of the top US commercial fishing ports; that and related support activities now dominate the town. It is also the closest US port to Bering Strait and the western Arctic Ocean, which is why we staged our expedition from here.

We enjoyed some of Dutch Harbor’s finest summer weather - easy winds, warm sun, and temperatures in the upper 50s. The treeless hills and lower slopes of the volcanic mountains were lush green with myriad low plants and wildflowers, humpback whales were breeching in the bay, and there were bald eagles overhead. What a great place for a walk after working in the labs! Dutch Harbor also offers a few restaurants and watering holes where science teams and off-watch crew congregated.

Well, that is literally behind us now, as we head north. There is a well- planned sequence of events to prepare the equipment for science use. For example, while docked at the pier we did in-water tests of one of the water sampling devices - the one not used for geochemistry - and this evening we will be soaking the main “clean-sample” geochemistry equipment to help purge the devices from minute traces of possible contaminants.

The part of the program I lead has to do with measuring and interpreting the distributions of the same seawater characteristics I and my colleagues have measured on most of my cruises over the years: the temperature, salinity, dissolved oxygen, and “nutrients” (nitrate, nitrite, phosphate, and silicate) in the water column from the surface to a little above the ocean bottom. And also similar to those other cruises, my colleagues on “hydrography” program will be determining the concentrations of ocean carbon parameters, CFCs (“freons”), and oxygen isotopes. Our team did similar work along part of the intended 2015 track in 1994 and another part in 2005, so we hope to be able to compare our measurements with the earlier ones. This is known by oceanographers as “repeat hydrography”, which is how the geochemists who lead this expedition refer to our work.

They, the geochemists, will meanwhile be determining the concentrations of various trace elements in seawater - “trace elements” because they are present in truly minute concentrations. Why? Because the ones they chose to measure are especially useful at illuminating the processes that interconnect the oceans, atmosphere, sea floor, continental shelves, rivers, ice, and so forth. The concept of “salinity” is based on the fact that to significant extent, the ratio of the various dissolved ions in ocean water (from sodium, calcium, potassium, sulfur, etc.) is nearly constant, no matter the location or the total concentration of all the salts. In other words, relatively fresh (lower salinity) water from the North Atlantic will have about the same ratio of sodium to calcium to potassium to sulfur ions as would a sample of salty (higher salinity) water from the subtropical Pacific Ocean. But there are variations, and they are important in telling us how the oceans work. In the case of this cruise, the geochemists are taking advantage of decades of earlier work to carry out a tightly focused exploration of the variations of a good number of the trace elements.

Hence this is the “US Geotraces Arctic Ocean cruise”, on which the hydrographic measurements provide crucial oceanographic context for interpretation of the geochemistry, as well a rare opportunity to address changes in the Arctic Ocean hydrography over the past 10 and 20 years.

We boarded yesterday and so have had enjoyed our first night’s sleep and first meals on board. We have been warmly welcomed and greatly assisted by the Coast Guard captain, officers, and crew, with whom we will spend the next two months. We are comfortable and ready to work. All is well.

Jim Swift

Research Oceanographer

UCSD Scripps Institution of Oceanography