sunlight and shadow at the same time in a pond covered with floating common duckweed plants

spirodela polyrhiza duckweed common duckmeat greater great freshwater habitat aquatic plant dense colonies water surface mat smooth round flat disc fastgrowing lifestyle tank floating used bio fuel industrial waste animal feed removing toxic substances urban treatment sunlight shadow time pond covered plants green duck pattern minor fresh small abstract texture dirty natural wild leaf background environment marsh detail beauty closeup nature mineral still grow invasive purifier autumn nutrient top float flora cleaning lake white cover beautiful lesser light freedom ray