Periphyton development and composition were studied in three different treatments: (i) two fishpond units of wetland-type wastewater treatment pond systems, (ii) two fishponds in combined intensive-extensive fish farming systems and (iii) three traditional polyculture fishponds. Results showed that amounts of periphyton developed in traditional polyculture fishponds (iii) were different compare...

Periphyton is a key component of the Everglades ecosystems. It is a major primary producer, providing food and habitat for a variety of organisms, contributing material to the surface soil, and regulating water chemistry. Periphyton is sensitive to the phosphorus (P) supply and P enrichment has caused dramatic changes in the native Everglades periphyton assemblages. Periphyton also affects P av...

Algal and plant production of nonphosphorus lipids in place of phospholipids is a physiological response to low phosphorus (P) availability. This response has been shown in culture and in marine plankton studies, but examples from freshwater algae remain minimal. Herein, we analyzed the nutrient contents and lipid composition of periphyton communities across the Florida Everglades ecosystem. We...

The use of stable C and N isotopes in food web studies, and as environmental indicators, requires deeper understanding of the factors that affect the signatures of primary producers. A laboratory experiment by Trudeau and Rasmussen (2003) demonstrated the negative effect of water velocity on periphyton C and N signatures (dC and dN). Under a range of water velocities normally found in lotic sys...

Periphyton is an important food source at the base of freshwater ecosystems that tends to bioconcentrate trace elements making them trophically available. The potential for arsenic-a trace element of particular concern due to its widespread occurrence, toxicity, and carcinogenicity-to bioconcentrate in periphyton and thus be available to benthic grazers is less well characterized. To better und...

We explored N2 fixation and alkaline phosphatase activity (APA) in periphyton from a N-limited stream ecosystem by coupling measurements of these processes with nutrient diffusion substrata (NDS) experiments. We measured periphyton biomass accumulation (as ash-free dry mass [AFDM] and chlorophyll a [CHLA]), N2 fixation, and APA to evaluate the relative importance of N2 fixation as an N source t...

Agricultural runoff often contains pollutants with antagonistic impacts. The individual influence of nutrients and atrazine on periphyton has been extensively studied, but their impact when introduced together and with multiple agricultural pollutants is less clear. We simulated a field-scale runoff pulse into a riverine wetland that mimicked pollutant composition typical of field runoff of the...

A set of experiments was carried out to determine what effects periphyton communities could have on near-bed hydraulic fields. We analysed velocity distribution, skewness and kurtosis coefficients, Reynolds stresses, relative turbulence intensity, coefficient of eddy diffusivity, velocity spectra, and turbulence scales at two flows with, and without, diatom-dominated periphyton on the bed. We f...

We analyzed Hg species distribution patterns among ecosystem compartments in the Everglades at the landscape level in order to explore the implications of Hg distribution for Hg bioaccumulation and to investigate major biogeochemical processes that are pertinent to the observed Hg distribution patterns. At an Everglade-wide scale, THg concentrations were significantly increased in the following...

This study was conducted to characterize periphyton biomass, productivity, and algal species composition, and to examine how these parameters changed seasonally over the course of two years in Walker Branch, a temperate forest stream. Seasonal variations in several factors potentially controlling periphyton (irradiance, streamwater nutrient concentrations, temperature, and the incidence of seve...