horse chestnut floating in water with on water covered with floating plants in the rich ecosystem of a eutrophic lake, ukraine

horse chestnut alga algae algal blooms aquatic biodiversity ecosystem plant plants araceae biological filtration biomass production carbon sequestration chlorophyll duckweed ecological role eutrophication floating fresh freshwater pond green background invasive species lake leaf lemnaceae macrophytes oxygen generation petal photosynthesis density propagation reproduction rootless seaweed small stagnant stratiotes surface swamp tiny water pollution wetland wolffia covered rich eutrophic ukraine park odessa