Biological Cycling of Phosphorus

Phosphodiesters include nucleic acids, phospholipids, and others. These compounds are labile and actively involved in biological cycling of phosphorus and are known to be important sources of DIP in aquatic environment (Chrost and Siuda, 2002). Turnover time of these compounds is short because of their rapid enzymatic hydrolysis by phosphodiesterases. The absolute quantity of DIP release during the hydrolysis of these compounds has not been determined in wetland soils. In aquatic environment, phosphodiesters were found to be one of the major sources of DIP in the water column. For example, enzymatically hydrolysable extracellular DNA contributes approximately... 

Phosphorus also occurs in all living things and the phosphate cycle, including the massive use of phosphatic fertilizers, is of great current interest.O 20) -pj.jg movement of phosphorus through the environment differs from that of the other non-metals essential to life (H, C, N, O and S) because it has no volatile compounds that can circulate via the atmosphere. Instead, it circulates via two rapid biological... 

The Atmosphere. - The Hydrosphere. - Chemical Oceanography. - Chemical Aspects of Soil. - The Oxygen Cycle. - The Sulfur Cycle. - The Phosphorus Cycle. - Metal Cycles and Biological Methyla-tion. - Natural Organohalogen Compounds. -Subject Index. 

In a general way, the overall movement of phosphorus on the continents can be considered as the constant water erosion of rock and transport of P in both particulate and dissolved forms with surface runoff to river channels and further to the oceans. The intermediate transformations are connected with uptake of P as a nutrientby biota and interactions between river waters and bottom sediments. The majority (up to 90%) of eroded P remains trapped in the mineral lattices of the particulate matter and will reach the estuaries and ocean without entering the biological cycle. The smallest soluble part of eroded phosphorus is readily available to enter the biological cycle (Figure 28). 

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