Premium
Influence of Vegetation on Long‐term Phosphorus Sequestration in Subtropical Treatment Wetlands
Author(s) -
Bhomia R. K.,
Reddy K. R.
Publication year - 2018
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/jeq2017.07.0272
Subject(s) - wetland , vegetation (pathology) , abiotic component , environmental science , organic matter , environmental chemistry , soil water , phosphorus , nutrient , water quality , ecology , hydrology (agriculture) , chemistry , soil science , biology , geology , medicine , geotechnical engineering , organic chemistry , pathology
Sustainable operation of a treatment wetland depends on its continued treatment of influent water to achieve desired outflow water quality targets. Water treatment or nutrient reduction is attained by a combination of biotic and abiotic processes. We studied one of the world's largest treatment wetlands established to revive the Florida Everglades from impacts of excessive phosphorus (P) inputs. Phosphorus retained in the treatment wetlands is sequestered within the accumulated material via biotic and abiotic pathways that are influenced by the existing wetland vegetation. Recently accreted soils (RAS) provide a major sink for stored P, and long‐term P removal efficiency of treatment wetlands is governed by the stability of accreted P because more stable P pools are less susceptible to mobilization and loss. We quantified reactive P (extracted with acid and alkali) and nonreactive P (not extracted with acid and alkali) pools in wetland soils by using an operationally defined P fractionation scheme and assessed the effect of emergent vs. submerged vegetation communities on stability of sequestered P. Reactive P comprised 63 to 79% of total P in wetland soils without a clear difference between two vegetation groups. The quantities of reactive P forms (inorganic vs. organic P) were significantly different between two vegetation types. A higher proportion of reactive P was stored as organic P in flocculent detrital organic matter (floc) and RAS under emergent vegetation (46–47% total P) in comparison with submerged vegetation (21–34% total P). The dominant P removal pathway in the submerged vegetation system was associated with calcium whereas plant uptake and peat burial appeared to be the main pathway in the emergent vegetation system. Core Ideas Nutrient reduction in treatment wetlands is attained by biotic and abiotic processes. Wetland vegetation communities play an important role in P removal pathways. Recently accreted soil (RAS) serves as the primary sink for retained P. Proportion of reactive P is higher in RAS than in underlying native soils.