PARENT SESSION
Poster Session #12: Marine Ecology.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
124
Nutrient limitation of benthic macrophytes in the upper Florida Keys: An in-situ nutrient enrichment experiment.
Ferdie, Meredith*,1, Fourqurean, James1, 1 Florida International University, Miami, FL
ABSTRACT- South Florida contains some of the most expansive documented seagrass communities in the world. Stoichiometry of seagrass tissue from the upper Florida Keys suggests that benthic coastal communities are phosphorus (P) limited inshore and nitrogen (N) limited offshore. This spatial variability hypothesis of nutrient limitation is presently being tested with a 15 month :in-situ sediment fertilization experiment. The objectives of this investigation are to determine the limiting nutrient for Thalassia testudinum growth and to assess the responses of inshore and offshore benthic communities to nutrient addition. Nutrient loading rates of 0.77 N and 0.09 P g m -2 d -1 are based on current estimates of dominant nutrient sources in the Florida Keys. Each site (3 inshore, 3 offshore) consists of 4 treatments (N, P, N+P, control) with six replicates, for a total of 144 experimental plots. We present the data from the first 10 months of nutrient enrichment for the response variables: seagrass productivity and leaf tissue C:N:P, sediment C:N:P, sediment chlorophyll a; total epiphyte load and epiphyte chlorophyll a. Results may be used to model changes that anthropogenic eutrophication may cause in the subtropical coastal marine waters of the upper Florida Keys.
KEY WORDS: Thalassia testudinum , Stoichiometry, nutrient limitation, seagrass