EM122 Water Column Sonar Data Collected During HLY1401

Study of Under-ice Blooms In the Chukchi Ecosystem (SUBICE) (HLY1401, EM122). The primary objectives of SUBICE were to determine the spatial distribution of large under-ice phytoplankton blooms on the Chukchi Shelf and the physical mechanisms that control them. The project utilizes new data obtained from both remote instrumentation (e.g. moorings,satellites) and an interdisciplinary ship-based field program to gain a better understanding of the physical/chemical conditions that favor under-ice bloom development as well as the physiological adaptations that allow phytoplankton to flourish beneath sea ice. The long-standing paradigm of the Arctic Ocean is one in which phytoplankton proliferate at the ice edge, supplying a substantial fraction of annual NPP and concentrating much of the food web in the MIZ. However, if under-ice phytoplankton blooms are widespread, then current estimates of annual NPP on Arctic continental shelves may be >10-fold too low. Our research program will allow us to determine the extent of under-ice blooms on the Chukchi Shelf and provide better estimates of production in these seasonally ice covered waters. It will also provide an improved understanding of the timing of phytoplankton blooms under the ice, in the MIZ, and in the open waters of the Chukchi Shelf, as well as the mechanisms controlling them.