underwater landscape, black sea. green, red and brown algae on the seabed

algae thickets algal flora algology algosociety aquatic biological black sea bluegreen ceramium cladophora ecological ecology enteromorpha environment eutrophication fauna green herd landscape macrophytes nature oxygen water synthesis pelagic photosynthesis porphira red riparian vegetation saltwater seaweed selfpurification ulva undersea underwater world wild wildlife