The Arctic Ocean Section (AOS) was a 1994 expedition in which two icebreaker vessels - the USCGC Polar Sea and the CCGS Louis S. St. Laurent - sailed from Nome, Alaska to the North Pole across the entire Arctic basin, covering over 2000 nautical miles.

The purpose of AOS was the increase understanding about the role of the Arctic in climate change and gather baseline data on contaminants in the region.

The significant science findings of the expedition were:

• The Atlantic layer of the Arctic Ocean was found to be 0.5–1.0^oC warmer than prior to 1993;
• A large eddy of cold fresh water was found centered at 1000 meters on the periphery of the Makarov Basin;
• Biological productivity was estimated to be ten times greater than previous estimates;
• An active microbial community was found; and
• Mesozooplankton biomass was found to increase with higher latitude.

Further Reading:

• Physical Oceanography Index
• Walter Tucker and David Cate, editors. The 1994 Arctic Ocean Section: The First Major Scientific Crossing of the Arctic Ocean. U.S. Army Cold Regions Research and Engineering Laboratory, 1996.
• P.Wheeler, M. Gosselin, E. Sherr, D. Thibault, R. H. Benner, and T. E. Whitledge. Active cycling of organic carbon in the central Arctic Ocean?: New measurements of biomass, primary production and dissolved organic carbon. Nature, 380:697–699, 1996.
• Arctic Ocean Section Porewater Chemistry Data, 1994
• Arctic Ocean Section 1994