each study site, quantitative standing crop data, leaf mark and 14 C uptake productivity 
data. 
1983 - 1987 
Powell, W. M., W. J. Kenworthy, and J. W. Fourqurean (1989) Experimental evidence for 
nutrient limitation of seagrass growth in a tropical estuary with restricted circulation. Bull. 
Mar. Sci. . 44:324-40. 
We studied the impacts of additions of nutrients to a seagrass community on a 
carbonate mudbank in Florida Bay. Shallow mudbanks dampen lunar tide in Florida Bay, 
and empoundment and channelization of the upland watershed (the Everglades) have 
reduced freshwater input, resulting in restricted circulation and reduced nutrient 
availability. Nutrients were supplied by seabirds defecating from experimental roosts. 
Seabirds used the roosts approximately 7% of the time so the input of nutrients was 
constant and quantifiable. The birds delivered approximately 2 - 4 g of excrement per 
day, resulting in an average loading rate of 0.052 g N and 0.009 g P m' 2 d-i. Only a 
portion of the excrement is immediately released as inorganic NH 3 and P0 4 ; about 80% 
reaches the sediment surface in a relatively insoluble form. There was a significant 
buildup of phosphate and ammonium in the pore water at the enriched, sites. The 
ammonium profile of low concentrations at the surface and then increasing with a steep 
slope through 20 cm suggests a rapid uptake and demand for mineralized nitrogen. 
Phosphorus in contrast had relatively high levels at the surface. Nutrient addition 
significantly increased areal leaf production and standing crop of Thalassia testudinum 
and Halodule wrightii. Above ground biomass at enriched sites averaged twice controls 
while below ground biomass was not significantly different between fertilized and 
control plots. Increased standing crop was produced primarily through longer, wider 
blades by Thalassia and longer blades and increased short shoot density by Halodule. 
Thalassia areal leaf production was 60% greater at enriched sites than at controls. 
Halodule areal leaf production increased by three orders of magnitude at enriched sites. 
Tissue nutrient content and nitrogen fixation assays suggest that phosphorus 
availability limits seagrass growth in unenriched conditions, but that nitrogen becomes 
limiting with the addition of bird excrement. 
1 984 
Ducommun, J. J., and C. D. Burke (1987) Interpretation of paleosalinities from two cores 
from Florida Bay. The Compass . 64(2):82-88. 
Florida Bay encompasses a wide variety of paleosalinity environments. The distribution 
of ostracode and foraminifer taxa in this area can be used to interpret the fluctuations 
in salinity that occur in the Bay. Populations of microfossils from Florida Bay were 
analyzed from two cores. Interpretation of these assemblages suggests that salinity 
ranged from normal marine to brackish water. Analysis of population parameters with 
statistical tests (e g, Kruskal - Wallis, Log ANOVA) suggests that the two cores 
originated from different environments. These statistical tests, however, could not 
pinpoint environmental changes within cores. 
1 984 
Fonseca, M. S., G. W. Thayer, and W. J. Kenworthy (1987) The use of ecological data in the 
implementation and management of seagrass restorations. Fla. Mar. Res. PubL 42:175-87. 
Effective restoration of seagrass systems can be implemented best through 
incorporation of basic ecological data into decision-making processes. The data are 
comprised mainly of seagrass population growth and coverage models. Careful selection 
of a site to be transplanted and monitored under strict performance standards offers 
functional restoration of a system. Environmental factors such as light, temperature, 
salinity, tidal range, and sediment stability may be used to determine a priori whether 
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