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Hydrologic Influence on Stability of Organic Phosphorus in Wetland Detritus
Author(s) -
Pant H.K.,
Reddy K.R.
Publication year - 2001
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2001.302668x
Subject(s) - drawdown (hydrology) , environmental chemistry , phosphorus , nutrient , organic matter , phosphate , wetland , water column , chemistry , humus , nitrate , detritus , environmental science , hydrology (agriculture) , groundwater , soil water , ecology , soil science , aquifer , geology , biology , biochemistry , geotechnical engineering , organic chemistry
Accretion of organic matter in wetlands provides long‐term storage for nutrients and other contaminants. Water‐table fluctuations and resulting alternate flooded and drained conditions may substantially alter the stability of stored materials including phosphorus (P). To study the effects of hydrologic fluctuation on P mobilization in wetlands, recently accreted detrial material (derived primarily from Typha spp.) was collected from the Everglades Nutrient Removal Project (ENRP), a constructed wetland used to treat agricultural drainage water in the northern Everglades. The detrital material was subjected to different periods of drawdown and consecutive reflooding under laboratory conditions. The 31 P nuclear magnetic resonance ( 31 P NMR) spectroscopy analysis revealed that sugar phosphate, glycerophosphate, polynucleotides, and phospholipids (glycerophosphoethanolamine and glycerophosphocholine) were the major forms of P in the detrital material. After 30 d of drawdown, polynucleotides were reduced to trace levels, whereas sugar phosphate, glycerophosphate, and phospholipids remained the major fractions of organic P. Microorganisms seemed to preferentially utilize nucleic acid P, perhaps to obtain associated nutrients including carbon and nitrogen. At the end of the 30‐d reflooding period, cumulative P flux from detritus to water column accounted for 3% of the total P (≤15 d of drawdown) and further decreased to 2% at 30 d of drawdown, but increased to 8% at 60 d of drawdown. The drawdown (≤30 d) not only reduced P flux to the water column, but also increased the humification and microbial immobilization of P. Excessive drawdown (60 d), however, triggered the release of P into the water column as the water content of detritus decreased from 95 to 11%.