The role of grazing on sea ice algae and sea ice bacteria by ciliates and flagellated (zooplankton) in Terra Nova Bay

Sea water was collected from a depth of 2 meters below the sea ice in the region of Gondwana Station in Terra Nova Bay. Initial measurements of chlorophyll along with presence and abundance of ciliates and flagellates were made. The collected water was then divided into a range of dilutions (with the addition of filtered sea water) and deployed under the ice for 24 hours. Subsequent chlorophyll a measurements were made from each sample to determine rates of phytoplankton growth and rates of grazing in the presence of variable grazer densities. This same experiment was modified using phytoplankton and bacteria from sea ice rather than algae, to assess the rates of sea ice algal growth and rates of grazing by zooplankton. The presence and grazing pressure of protists on bacteria within the sea ice was determined by adding fluorescently labelled beads as prey surrogates to a melted sea ice samples containing grazers and using fluorescence microscopy to determine the rate of uptake over time.