Global warming and other climate-related processes are rapidly changing the Arctic Ocean. Summer sea ice is disappearing and the sea surface is warming and becoming less salty. This changing physical environment is altering basic biological processes and air-sea exchange of gasses. The carbon cycle is of particular interest in the Arctic because it is unknown how carbon dioxide sources and sinks are changing and whether these changes will lead to increased greenhouse gas accumulation in the atmosphere. It is thought that with less ice cover the Arctic Ocean will absorb more human-produced carbon dioxide. Higher carbon dioxide levels cause the ocean to become more acidic because carbon dioxide forms carbonic acid when it dissolves in water. The increase in the acidity of the water can affect the food web by harming shell-forming organisms. In spite of these important issues, not much is known about the carbon cycle in the central Arctic Ocean basins. Nearly all measurements of ocean acidity have been made on the Arctic shelves during the summer period when access is easy. We will measure the amount of dissolved oxygen and carbon dioxide in the surface water and its acidity in the central Arctic Ocean during a summer cruise on the ice breaker Louis St. Laurent and on year-round oceanographic moorings. Outreach activities include continued operation of an ocean acidification exhibit that we developed for University of Montana?s science museum which has been seen by thousands of museum visitors.
The research will specifically support installment of a shipboard underway pCO2 system along with deployment of pCO2, pH, and photosynthetically active radiation sensors on the Woods Hole Oceanographic Institution time-series moorings in the Beaufort Sea. The ship follows the same cruise track since the program began in 2003, starting south on the Beaufort shelf and extending to the northern Canada Basin. Three moorings are deployed annually with a subsurface profiler that measures conductivity, temperature, depth, and dissolved O2. Our sensors are deployed at ~35 m depth, just below the subsurface float. These data will allow us to compute air-sea CO2 fluxes and net community productivity during periods when there is less than 100% ice cover and photosynthetically active radiation is greater than zero. The quality-controlled shipboard and mooring data will be made available to the scientific community by submission of the data to the Arctic data repository (ACADIS).
