green plants and algae on a wet rocky slope on serpent's island, ukraine

alga algae bath beach benthic biology black sea bluegreens chloroplast closeup creek cyanobacteria cyanobacterium cyanophytes down rocks ecology ecosystem environment filamentous freshwater green island microorganisms microscopic nature nostoc sp plant prokaryotic scenic singlecelled snake spirogyra underwater water wildlife zmeiniy tree bright background landscape outdoor