Kelp, a type of algae, is the
fastest growing plant in the sea, growing 2 feet a day under
the ideal conditions. Algin (kelp extract) is used in ice
cream as a thickening agent.
Kelp forests are an entire ecosystem unto themselves,
sheltering snails, starfish, crabs, sea cucumbers and other
creatures, as well as providing a food source for animals that
feed on algae.