Phosphorus Cycle in Water
Phosphorus (P), like nitrogen, is an important nutrient element that is required
by the cells of all living things. Many important molecules within cells contain
phosphorus atoms. For example, adenosine triphosphate (ATP) is a phosphorusbearing
compound. It occurs in every living cell, where it plays a key role in storing
energy. Other nutrients such as nitrogen, are found as gases. Phosphorus does
not have a gasous phase under natural conditions. This means that once present
in an aquatic system it will tend to be stored unless physically removed.
Excluding phosphorus carried as dust in the wind, and the amounts transported
for human use, phosphorus is carried by water. The amount of phosphorus found
in the surface water, such as streams and lakes, is the product of a complex
set of relationships. These include:
geologic processes - the weathering of rocks;
atmospheric imputs - phosporus carried as wind-borne dust;
biologicaland chemical prosses that recycle phosphorus;
patterns of flowing water, which transport materials containing
phosphorus;
shape of landforms, which determines patterns of erosion and
deposition;