Ecomare

Plants make up the basis of all life, whether on land or in the sea. However, there aren't many plants that can survive in salt water, day in, day out. Almost all plant life in sea consists of microscopically small algae in suspension: the phytoplankton. That foam you sometimes find on the beach comes from phytoplankton species which have died. The small percentage of plants which are not phytoplankton grows attached to the sea bed, eelgrass and seaweed. But they too need sunlight to grow just like plankton. You only find these plants in shallower areas where enough sunlight can penetrate.