Periphyton as a potential phosphorus sink in the Everglades Nutrient Removal Project |
| |
Authors: | Paul V. McCormick Robert B.E. Shuford III Michael J. Chimney |
| |
Affiliation: | aEverglades Division (MSC-4440), South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, FL 33406, USA;bSTA Management Division (MSC-4470), South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, FL 33406, USA |
| |
Abstract: | Phosphorus uptake and release by periphyton mats were quantified in the Everglades Nutrient Removal Project (ENRP) to evaluate the potential for periphyton P removal. Short-term P uptake rates were determined by incubating cyanobacteria (Oscillatoria princeps and Shizothrix calcicola) and Chlorophycean (primarily Rhizoclonium spp.) algal mat samples for 0.5–2 h under ambient conditions in BOD bottles spiked with soluble reactive P (SRP). Cyanobacterial mats removed P more than twice as fast (80–164 μg P h−1 g−1 AFDM) as Chlorophycean mats (33–61 μg P h−1 g−1 AFDM) during these incubations. In a longer term study, fiberglass cylinders were used to enclose 1.8 m2 plots within the wetland and were dosed weekly for 7 weeks with: (1) no nutrients; (2) SRP (0.25 g P m−2 week−1); or (3) SRP plus nitrate (0.42 g N m−2 week−1) and ammonium (0.83 g N m−2 week−1). Phosphorus uptake rates by this periphyton assemblage, which was dominated by the chlorophytes Stigeoclonium spp. and Oedogonium spp., were measured weekly and were similar among nutrient treatments on most dates, indicating that the algal storage compartment for P was not saturated despite repeated P additions. Decomposition rates and P loss by cyanobacteria and Chlorophycean mats were determined by measuring biomass loss and SRP release in darkened BOD bottles over 28–42 day periods under anaerobic and aerobic conditions. First-order aerobic and anaerobic decomposition rates for cyanobacterial mats (k = 0.1095 and 0.1408 day−1, respectively) were 4–20-fold higher than rates for Chlorophycean mats (k = 0.0066 and 0.0250 day−1, respectively) and cyanobacteria released considerably more P back to the water column. Our findings suggest that periphyton can be an important short-term sink for P in treatment wetlands and that retention is strongly affected by the taxonomic composition of the periphyton assemblage. |
| |
Keywords: | Algae Constructed wetland Everglades Nutrient Removal Project Microcosm Periphyton Phosphorus |
本文献已被 ScienceDirect 等数据库收录! |
|