2017-2018 USAP Field Season
Using bio-acoustics on an autonomous surveying platform for the examination of phytoplankton-zooplankton and fish interactions in the Western Ross Sea
Dr. Grace Saba
Supporting Stations: RV/IB Nathaniel B. Palmer
The quantitative linkages between primary producers and the higher trophic levels, specifically the processes responsible for the regulation of abundance of middle trophic levels dominated by copepods and crystal krill (Euphausia crystallorophias), are virtually unknown in the Ross Sea. Using a glider equipped with a multi-frequency echo sounder, researchers will conduct a quantitative assessment of simultaneous spatial distributions of phytoplankton, zooplankton, and Antarctic silverfish in Terra Nova Bay and the surrounding shelf waters. The addition of the bioacoustic echo sounder on a glider is a new system that has not yet been deployed and tested widely. These novel data will allow for the investigation of trophic interactions between these three trophic levels as well as their relation to physical drivers.
Field Season Overview
Two participants will sail on the RVIB Nathaniel B. Palmer from Punta Arenas, Chile to Terra Nova Bay. Their primary objective on this cruise is to deploy the Slocum G2 glider with the integrated Acoustic Zooplankton and Fish Profiler (AZFP). The team will also deploy various net systems in order to ground truth the acoustic data from the glider.
The three major components of this work include: (1) An acoustic survey with one, 4-to-6 week deployment of a Slocum glider with an AZFP package to map distribution and abundance of phytoplankton, multiple zooplankton taxa, and silverfish during the spring-summer transition along TNB polynya ice shelf and in continental shelf waters adjacent to TNB; (2) Ship-based acoustic sampling via the hull-mounted EK-60 during ship transit when possible to complement glider-based acoustic measurements; and (3) Ship-based sampling of zooplankton and silverfish using net tows and mid-water trawls to validate acoustic data of taxa composition and size collected from the glider deployment. ASC Marine Technicians will recover the glider on leg two of the NBP18-01 cruise without a project participant present.
The operations to support this project requires collaboration and flexibility with the other science teams on board. Net tows will need to occur opportunistically during transits between the other science team’s CTD (Conductivity-Temperature-Depth) and TMC (Trace Metal Clean) cast stations. Current-tracking drifters will dictate where the ship is required to be.
Deploying Team Members