| This study investigated the ecosystem interactions and processes of algae in the Florida Everglades, where phosphorus pollution threatens ecological health. Two different studies, 1995 and 1996, were conducted in which algae were sampled along a phosphorus gradient in WCA-2A to determine the relationship among phosphorus enrichment and sedimentary algae, floating cyanobacterial mats, and Eleocharis periphyton. The first objective was to explain the effects of phosphorus at different taxonomic levels on sedimentary algae by using CA, CCA, and Pearson's correlations. Relative abundance of diatoms declined while cyanobacteria increased with higher P concentrations. Sedimentary phosphorus explained more variation in taxonomic composition of sedimentary algal assemblages than water column or floating mat P. The cyanobacteria with heterocysts, 5 algal genera and 7 algal species were positively correlated to phosphorus concentrations, while 3 genera and 7 species were negatively correlated. The second study developed cyanobacterial indicators that inferred P conditions from species composition of cyanobacterial mats and Eleocharis periphyton using weighted average regression techniques. Green algae had a lower phosphorus optima and tolerances than cyanobacteria. Epiphytic species had a smaller optima range and lower tolerances than floating mats. The best inference model was the epiphytic cyanobacteria model for surface sediment P (WAjack r2 = 0.4236). Cyanobacteria were a reliable indicator of phosphorus when compared to other studies and should be used in assessing the Florida Everglades. The third study investigated variability in scytonemin, carotene, chl a, and phycobiliproteins concentrations with time and depth in floating mats. Scytonemin, which shields algae from UV-radiation, was abundant throughout the mats. Carotene, chl a, and allophycocyanin concentrations increased significantly with depth in mats. All pigment concentrations increased, some as much as 3-fold, from 0800 to 1300 hrs and then declined. This may represent a diurnal cycle of resource allocation to optimize light harvesting and cell growth, which has implications for timing of sampling and estimating biomass with pigment concentration. The final study was an algal taxonomic survey of WCA-2A and Big Cypress National Preserve. 123 species were identified with 62 Cyanophyta, 46 Chlorophyta , 2 Euglenophyta, 1 Bacillariophyta and 1 unknown structure. This was the first report for 9 Cyanophyta and 2 Chlorophyta species from the United States and 56 Cyanophyta, 21 Chlorophyta and both euglenoid species to the state of Florida. |
