Senior Theses 2005
Carey Lynn Perry (2005). Nutrient composition of sea grasses
in Florida's big bend region
Faculty advisor: Jeannine Lessmann
Nutrient loading to Florida's Big Bend coastal waters in the northeastern Gulf of Mexico has dramatically increased as the result of local development and land use changes in the SuwanneeRiver watershed. The main objectives of this study were: (1) To investigate the utility of the three dominant sea grasses, Halodule wrightii, Syringodium filiforme, and Thalassia testudinum, as nutrient bio-indicators in Florida's Big Bend; (2) To examine if sea grass nutrient composition varied between species in the region; and (3) To examine the regional differences in seagrass nutrient composition along the Big Bend coast with respect to a suspected nutrient source input, the Suwannee River. Leaf nutrient composition (carbon, nitrogen, phosphorus, and elemental ratios) of Halodule wrightii, Syringodium filiforme, and Thalassia testudinum was determined at 336 sites in 5 sub-regions in 2002 and at 127 sites in 4 sub-regions in 2003. Greater variation in nitrogen, phosphorus, and elemental N:P ratios of Halodule wrightii, along with the observation of decreasing nutrient concentration with distance from the SuwanneeRiver, suggest that this species might be a better bio-indicator of nutrient availability in the Big Bend region than Syringodium filiforme and Thalassia testudinum. Results from this study suggest that Halodule wrightii may play a substantial role in future management of nutrient loads and determination of ecosystem health in the Big Bend region of Florida. As nutrient loads increase in the future, the two other species may prove more useful as bio-indicators of environmental nutrient status.