Description From bryozoans and snails to shrimps, eels, swordfish, and whales, the Sargasso Sea provides a home to countless types of marine life, thanks to the prevalence of microalgae called sargassum. Following a single blade of this extraordinary seaweed as it grows and spreads, readers see what it provides for the sea's organisms: a base for hydroids and tube worms to filter and feed, shelter for anemones and nudibranchs and their nutritious waste, hunting grounds for crabs and amphipods, and a source of nourishment and protection for the fish, birds, whales, and reptiles that feed on these smaller creatures.