dense covering of rotting algae on water

alga algae aquatics background blanket blanketed bloom blooming brown carpet choking colors contaminate contamination covering dense deoxygenate deoxygenating depletion dirt dirty disgusting ditch enriched environment environmental eutrophic eutrophication floating freshwater green layer methane minerals nature nitrogen nutrients oxygen phosphate polluted pollution pond problem rotting scum several slime stagnant stinking suffocate suffocating surface swamp swamping texture vegetation water