The Autonomous Polar Productivity Sampling System (APPSS)
PI: Mike Steele
This part of the larger NASA ICESCAPE project examines the long-term, seasonal variability in phytoplankton abundance as a function of changes in sea ice cover, stratification, and temperature regimes measured in the Beaufort and Chukchi Seas throughout the growing season. This will be accomplished by making high frequency observations using ARGO floats with near-real time satellite communication. For the deeper waters to the north of the Chukchi Sea and in the deep Beaufort Sea, an ARGO float will be built that will cycle between 300 m depth and the surface. The floats will measure temperature, conductivity, dissolved oxygen, fluorescence, and backscattering. In addition, floats deployed in 2011 will have a nitrate sensor to estimate NO3- consumption, new production and net community production. These single point field measurements will be used to validate key remotely sensed variables such as sea surface temperature and salinity, chlorophyll a, and primary production. Satellite data will also be used to scale up the single point drifter measurements to the regional scales of the Beaufort and Chukchi Seas.
Finally, the combination of a recently compiled data set of historical values of pan-Arctic primary production and chlorophyll a with an existing Arctic Ocean hydrographic database will allow examination of case studies in order to better understand the temporal evolution of primary productivity and its physical controls in this rapidly changing ecosystem over the spring, summer, and fall seasons. The paucity of existing primary production data in the Beaufort and Chukchi Seas, and the Arctic Ocean as a whole, in space and time and the difficulty of obtaining higher frequency data by expensive and infrequent ship-based measurements beg for a field based approach that is complementary to, and supportive of, the cloud and ice limited satellite measurements possible in the Beaufort and Chukchi Seas.