Photosynthetic organisms use sunlight to provide the energy necessary to combine carbon dioxide and water to form organic molecules and ATP. Those same photosynthetic organism also use cellular respiration to breakdown those organic molecules whenever there is an energy demand greater than what can be provided by photosynthesis or in the absence of light.
Answer:
Excess nitrogen can cause over-stimulation of growth of aquatic plants and algae. Excessive growth of these organisms, in turn, can clog water intakes, use up dissolved oxygen as they decompose, and block light to deeper waters. So few organisms live in these conditions or even can suffocate and die.
