Post by the VIMS Palmer-LTER Research Team
After dropping off the birders at Avian Island, we had a full week of science ahead of us. We traversed 100’s of kilometers to sample near the coast and offshore in the deeper regions of the peninsula. When we reach a predetermined station (i.e., sampling location), collaborating labs on the ship deploy an AC-9 that measures turbidity and particle size in the water. The Conductivity, Temperature, Depth (CTD) is then deployed to the bottom of our station. When we sample near the coast, the bottom depth is relatively shallow (~300 m) so it takes less than an hour for the CTD to return to the surface. However, at the deeper, offshore stations we reach up to 3000 m and the cast can take 3 hours!
A fun thing we do at our deep stations is to send the CTD down with colored Styrofoam cups which shrink to more than half their size due to the immense pressure they are exposed to at 3000 m. It is a fun keepsake to give to friends and family upon our return from the cruise. Once the CTD has returned to the surface, it is time for our zooplankton tows! We do a two meter (2×2 meter) square net with a large mesh size to catch large zooplankton like krill. We then deploy a smaller 1 meter (1×1 meter) net to catch smaller zooplankton such as copepods. Occasionally we will also do additional tows to catch animals to be used in experiments.
Dr. Steinberg has been using Antarctic Krill, Euphausia superba, and gelatinous salps, Salpa thompsoni, to conduct fecal pellet experiments as a way to measure zooplankton contribution to carbon flux (through poop!) in the WAP. Her Ph.D. student, Tricia, is also conducting experiments with an open ocean snail called a pteropod. Tricia is interested in determining how increasing temperatures and limited food availability affect pteropod respiration and excretion. She has been conducting a series of these experiments and so far has found that pteropods exposed to high temperatures (~4 °C) and low food may be the most physiologically stressed.