Dispatch 29: A Closing Word from the Chief Scientist     Print

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Bill Williams

October 17, 2015

We are now steaming east towards Kugluktuk with the west wind on our backs. Our 13^th annual science mission is completed successfully, thanks to the Captain and Crew of the Louis and science teams from WHOI, Fisheries and Oceans Canada, and other teams from the USA and Japan. At the end of each expedition we make a map showing our track and science stations along the way (Figure 1). This year there were 4 mooring recoveries, 3 mooring deployments, many buoys deployed in the ice as part of 2 Ice-Based Observatories, 3 buoys opportunistically recovered, 53 XCTDs and 70 CTD/Rosettes.  During our 27 days at sea, an enormous 11,717 water bottles were filled with sea water for geochemical analysis from the Niskin bottles on the rosette. With these we will be able to trace waters that flow in the Arctic Ocean, but that originate from elsewhere, from rivers, from the Pacific Ocean and from the Atlantic Ocean. We will also be able to learn more about the structure of the ecosystem in the Beaufort Gyre and how it changes with changing ice cover.

This year we steamed anticlockwise around our grid of stations, so that we headed to the north first and then slowly worked our way south and back east as the days began to grow shorter and colder.  As we started south, it looked like we would quickly be in open water, but the north wind both pushed the ice pack south and brought cold air that made open water begin to freeze rapidly, forming large areas of new nilas and pancake ice. It has been amazing to see this onset of winter first hand after the 4^th largest summertime sea ice melt in the Arctic. The growth of ice was obvious at mooring site BGOS-A. On our first visit to BGOS-A, for mooring recovery, on October  5^th,  we were in open water at the edge of the ice and the surface layer of the ocean was above freezing. On our return, 2 days later on October 7^th, there was 4 cm of new ice and the surface layer of the ocean was now at the freezing point and had become saltier from the salt that is left behind in the ocean as the ice grows.