If facilities permit, you may want students to look at the site as well. The Bdeltoid rotifers are the ones with which I worked in Lake Hoare. Extensions can be at the discretion of the teacher. Some students may want more individual time to explore other ideas. Perhaps one or two students can assume the role of class recorders.
Students can also document the discussion in their lab notebooks.
Ask students to share their ideas about food webs and food chains in their local area. Then ask students to discuss in small groups what they think might be part of the food web in the perennially ice covered Lake Hoare in the Taylor Valley in the trans-antarctic mountains. Ask students to consider the kinds and numbers of things living in a local lake. Then compare the list to what they think might be in the Antarctic lake. Have students think about food availability.