Distribution and overwintering strategies of krill
Carin Ashjian, Cabell Davis, Scott Gallager, Peter Wiebe, Woods Hole Oceanographic Institution
The Southern Ocean GLOBEC project is studying
the overwintering strategies of krill (Euphausia superba)
in the Antarctic Ocean. Krill are critical species in the Antarctic
ecosystem and provide food for a rich upper trophic level community
including seabirds (e.g., penguins), seals, and whales. Despite
years of study, the overwintering strategies of krill remain unidentified.
In this project, a multi-institution, multi-disciplinary team of
scientists is examining the physical and biological characteristics
of Marguerite Bay, Antarctic Peninsula, and the neighboring continental
shelf to elucidate how and where krill survive the winter.
My research is part of a larger effort by a group of WHOI scientists to describe the horizontal and vertical distribution of zooplankton, especially krill, in association with physical characteristics on the shelf using an array of instruments. Much of our work involved surveying the shelf with the BIOMAPERII towed vehicle equipped with upward and downward looking acoustic transducers at five frequencies to measure acoustic backscatter, a CTD to measure temperature and salinity, a fluorometer, and a Video Plankton Recorder (VPR) to determine the high resolution vertical and horizontal distribution of zooplankton, including larval krill. This instrument is towed behind the ship, profiling vertically from 20 - 250 m. We also sampled at selected sites using a MOCNESS (Multiple Opening Closing Net and Environmental Sensing System) to collect zooplankton from discrete depths for identification and measurement purposes and with an ROV equipped with a VPR to document the under ice distribution of krill. My specific work involves describing the distribution of zooplankton taxa from the MOCNESS samples and the high resolution distribution of larval krill from the VPR.
I'll be adding more information about this project later. Meanwhile, please see the Southern Ocean GLOBEC web page.
This project is funded by the National Science Foundation.