Description of Periphyton Sample Clauses

Description of Periphyton based Stormwater Treatment Areas Presence of a periphyton community adapted to low water column P concentrations is considered the central element that leads to superior P removal performance by the PSTA technology. Periphyton communities are complex assemblages of cyanobacteria, eubacteria, diatoms and eukaryotic algae and are found in lakes, streams and wetlands, including the marshes of the Everglades (XxXxxxxxx and O’Dell 1996). Several characteristics of periphyton communities make them well suited for biological treatment of surface waters in wetlands (Xxxxx 2003). Floating and benthic calcareous periphyton mats are a key component of the ultra-oligotrophic Everglades marshes (Xxxxxxx et al., 1994), and are thought to be capable of reducing water column TP to extremely low levels. Periphyton typically has a high affinity for P and responds to P inputs more rapidly than other wetland components (macrophytes, soils) and thus is important in the uptake and storage of P (XxXxxxxxx et al., 1996). Typically, periphyton growth in PSTA systems is encouraged by several design features, including a benthic surface dominated by calcitic minerals, typically limerock; limited densities of emergent macrophytes, to reduce shading; and shallow water depths, to support light penetration. Periphyton-based systems appear to produce lower particulate P (PP) and dissolved organic P (DOP) concentrations, relative to muck-based EAV and SAV marshes. Phosphorus in those pools is less available for biological uptake or chemical sorption than soluble reactive P (SRP), and so more difficult to remove in treatment wetlands. Under certain conditions, however, PP and DOP can be broken down through hydrolysis reactions into more bioavailable forms of P. Phosphatase enzymes are naturally-produced proteins that catalyze these hydrolysis reactions, effectively increasing the transformation of selected DOP and PP molecules into more bioavailable P forms. Phosphatases are found internally within organisms and as extracellular moieties within the aquatic environment (Xxxxxx 1991). In ultra-oligotrophic south Florida marshes, periphyton mats are thought to be a key locus for production of these enzymes. It is believed that excessive inputs to a wetland of readily available P (such as SRP), either through inflow waters or via sediment-to-water column flux from enriched sediments, can constrain the development of periphyton adapted to low-P conditions, as well as the production of phosphata...