Everglades (Fla )

Differences in relative primary productivity of periphyton were determined for three light regimes: open slough (control), sawgrass canopy, and cattail canopy. The center of Water Conservation Area 2-A, Everglades was chosen as the study site because it is relatively unaffected by nutrient runoff. Periphyton productivity was determined by the light and dark bottle method, and biomass was recorded as ash-free dry weight. Statistically significant correlations were found between periphyton biomass and water temperature and between organic content and water temperature. Mean photosynthetically active radiation reaching the surface of the water under sawgrass and cattail canopy was 45% $\pm$ 3% and 11% $\pm$ 1% respectively. Relative primary productivity of periphyton was lower under cattail canopy than under sawgrass canopy due to increased shading of cattail. This reduction of periphyton biomass and primary productivity can be considered an indirect effect of nutrient enrichment from the Everglades Agricultural Area.

This thesis is intended to explore the genetic variation between cattail species (Typha spp.), within T. domingensis in different locations, anthropoegenic conditions, and possibly discover a hybrid in the Florida Everglades. Typha domingensis is the dominant cattail species in the Everglades, while Typha latifolia a less common species is also present. Five nuclear and chloroplast protein encoding genes from around 20 samples of cattail plants were collected randomly in the Water Conservation Areas of the Everglades Protection Act, cloned and sequenced. The results of sequencing showed differences between the two species studied, using an insertion within an intron of the Type 2 Metallothionein-like protein gene as a marker to differentiate between the two species. A high degree of nucleotide polymorphisms interspecifically was revealed. Species identification based on morphology is not always reliable that is why our marker must be utilized to confirm the identity of a plant.

The Big Cypress Swamp and the Everglades of South Florida are inherently oligotrophic ecosystems that in recent decades have been subjected to increasing agricultural nutrient inputs. While extensive research regarding deleterious effects of nutrient impacts has been conducted in the phosphorus-deficient Everglades, there is a lack of research in Big Cypress Swamp. This 12-month field study assessed the responsiveness of Taxodium distichum, Fraxinus caroliniana, and herbaceous vegetation to increased nutrient levels in Big Cypress Swamp. Six nutrient treatments (Control, N, P, K, 2K, and PxK) were applied to the soil surrounding these trees. F. caroliniana had higher photosynthetic rates with 2K treatments and higher growth rates with PxK treatments. T. distichum had higher Leaf Area Index in the P and PxK treatment but did not exhibit other responses to treatment. Herbaceous vegetation showed little response to treatments. This study concluded that potassium may be co-limiting in this ecosystem.

To improve water quality as part of a large restoration effort, constructed herbaceous wetlands will be used as filters of high nutrient water. In this study, I tested whether mixed forested wetlands could also be used as nutrient filters. I examined water quality parameters within a forested slough isolated from direct anthropogenic disturbance and within an impounded forest wetland receiving direct agricultural effluent. Among the water quality parameters, TP and K concentrations in the forested slough were particular low. Although all nutrients, except TKN, were higher in the impounded wetland, nutrient concentrations within the wetland were lower at interior sites as compared to inflow water. Based on the use of chloride as a conservative tracer, this reduction resulted predominantly from biological and chemical processes, while physical processes played a minimal role. This study established that mixed forested wetlands can significantly reduce high nutrient levels in surface water.