Ctenophores, like this Beroe species are often found accompanying swarms of medusae in the water column. Commonly called "comb jellies", these open water inhabitants use hair-like projections called cilia to move through the water. They are also carnivorous, feasting on prey almost as large as themselves. Zooplankton is an important food source for a variety of marine organisms, including baleen whales. (photo: Shane Anderson)