Floats on docks, such as those at marinas, support an amazing variety of organisms. Organisms that attach to floating objects in the ocean are called "fouling organisms. Floats provide a solid substrate to which animals and algae attach. Since this zone is rarely disturbed by natural forces apart from ice, a highly diverse yet stable community forms. Diatoms, green alga and red algae often settle first, forming a pale green film on the floats. Then come the larger green algae. Along with the algae a host of animals settle here. Juvenile barnacles forming solid banks of tiny volcano-shaped tests. Blue mussels, attached by byssal threads, often form thick beds that appear to shut out all other organisms.
Rockport Harbor - Rockport, Maine