CHEMICAL FLUCTUATIONS DUE TO SEASONAL AND CROPPING EFFECTS ON AN ALGAL-SEAGRASS COMMUNITY

Benthic algae as well as blades and short shoots of Thalassia testudinum Banks ex König (turtle grass) were collected from caged plots in February, May, and October off Tarpon Springs, Florida in 1 m of water. The study was designed to determine chemical changes in algal and seagrass components from a seasonal and regrowth standpoint. Thalassia blades had ash levels of 30-40% while the algae had levels of 60-70%, both components were cut off at the surface and in plots where all plants were cropped to 5 cm above the substrate. Protein levels ranged from 3 to 12% for turtle grass and 2 to 5% for algae with highest levels in the spring and in regrowth plots. Soluble carbohydrate levels were 3-12% for turtle grass and 6-10% for the algae with highest levels in the late spring and fall. Calculated energy levels were constant over the year (1.75 to 1.80 × 104 l/g organic wt.) for both Thalassia and the algal components. The study demonstrated that the algal component was energetically equal in importance to turtle grass. © 1979.