Phosphorus Uptake and Storage in Biotic Communities

Microorganisms also can play a major role in retaining phosphorus in wetlands with organic matter inputs or those producing large quantities of detrital matter internally as a result of high primary productivity. Microorganisms incorporate dissolved phosphorus into cellular constituents. 

FIGURE 9.40 Influence of phosphorus loading on microbial biomass phosphorus in soils of northern Everglades. (From Chua, 2000.) 

FIGURE 9.41 Influence redox potential and electron acceptors on microbial biomass in organic soil. (Adapted from McLatchey and Reddy, 1998.) 

Benthic periphyton utilizes phosphorus from both soil and the water column, whereas floating periphyton receives phosphorus largely from the water column. Epiphytic periphyton receives phosphorus largely from the water column and phosphorus released from senescent macrophyte tissue. A small amount of phosphorus is also derived by epiphytic periphyton from living tissue of macrophytes. Chemical composition of periphyton varies depending on water column phosphorus, water flow, and type of macrophytes. Phosphorus content of periphyton is in the range of 

5 mg g (dry weight), but the phosphorus content of 1.1-2.2 mg g is necessary for normal growth. High phosphorus concentrations reported are the result of luxury uptake, which is commonly observed in enriched water. Periphyton may reach phosphorus saturation at relatively low water column phosphorus concentrations ( 0.025 mg L ). 

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