dead colony of common freshwater sponge swim with strong current in a shallow freshwater river with clear water

air algae aquatic background balance biotope branch brook bubble clear climate colony colorful common contrast crystal current dead demosponge dense detritus disaster ecology ecosystem environment environmental europe explore flora flow freshwater gravel green ground human impact lacustris lake litter live moderate movement nature organic particle plant porifera ray river sand season shallow sponge spongilla spongillidae stream strong substrate sun swim temperate ukraine underwater unusual vegetation vinnytsia vulnerable water wilderness wonder