This collaborative research project represents one of the first comprehensive biological process studies to be carried in the Arctic Ocean over a full annual cycle. Investigators from Oregon State University, the Canadian Dept. of Fisheries and Oceans, and from other U.S. institutions will use a Canadian icebreaker as home base for a 14-month period to study the seasonal cycle of biological production and respiration, and the seasonal cycle in biomass of algae, bacteria, protists, and zooplankton, in the central Arctic. The research program will be organized around continuous measurement of dissolved oxygen concentration in the upper water column. Dissolved oxygen content integrates the sum of production and respiration in both the water column and in the overlying sea ice. Continual monitoring of dissolved oxygen will allow detection of the initial spring increase in primary production, and of transient algal blooms, that may be missed by a discontinuous sampling program. Concentration of inorganic nutrients in the upper 100 m, concentration of dissolved and particulate organic matter in the water and in sea ice, biomass of autotrophic and heterotrophic organisms in the water column and sea ice, uptake rates of carbon and nitrogen by phytoplankton, and respiration rates of the planktonic community, will be analyzed at least weekly. The seasonal study of production/respiration processes will provide valuable information regarding: 1) the present structure and function of central Arctic ecosystems, which can serve as a baseline for evaluating the impact of future global change processes in this sensitive region; and 2) the nature and timing of production and respiration processes in a high latitude system and in particular how the heterotrophic community survives during the dark winter months.