Mapping and monitoring of submerged aquatic vegetation in Escambia-Pensacola Bay System, Florida

Abstract

Recently, the distribution and changes in submerged aquatic vegetation (SAV) in the Escambia-Pensacola Bay System in northestern Florida were monitored by two techniques. One technique used divers to measure changes in the deepwater margin of beds and provided horizontal growth measurements to the nearest centimeter, the other used a differential global positioning system (DGPS) on a small boat to map the perimeter of SAV beds in shallow water. Current distribution of SAV in Escambia Bay shows that most of the SAV losses that occurred during the 1950s to 1970s have been recovered. In Santa Rosa Sound and Pensacola Bay, SAV showed significant increased growth with horizontal growth rates of some beds averaging more than 50 cm over the past year. In Big Lagoon, however, SAV has declined an average of 10 cm in horizontal coverage along the deepwater edge. Water quality and photosynthetically active radiation light measurements from the Escambia-Pensacola Bay System suggest that increased light availability was associated with the increased seagrass coverage in Santa Rosa Sound and Pensacola Bay, and elevated nutrient concentrations were associated with the seagrass declines in Big Lagoon.