It is a compound of nitrogen in combination with oxygen. Nitrate is highly soluble in water and is stable over a wide range of environmental conditions. It is readily transported in ground water and streams. They are compounds of phosphorus in combination with oxygen and hydrogen. Phosphates are only moderately soluble and, relative to nitrate, are not very mobile in soils and ground water.
Phosphates tend to remain attached to soil particles.
Algae feeding on these nutrients grow into unsightly scum on the water surface, decreasing recreational value and clogging water-intake pipes. Decaying mats of dead algae can produce foul tastes and odors in the water and remove oxygen from the water, occasionally resulting in fishkills. Algae growth is often limited by the available supply of phosphate or nitrate. Human activities can accelerate eutrophication by increasing the rate at which nutrients enter the water.