Largo are in an area with the best present-day reef development; the two off Long Key 
are in an area with minimal patch reefs and where major passes allow Florida Bay 
water to flow onto the Florida reef platform. Two patterns of nutrient distribution 
emerged. Off Key Largo, and from Ohio to Looe Key, concentrations of N and 
chlorophyll-a were elevated near marinas and canals, but returned to oligotrophic 
levels within ca. 0.5 km of shore (e.g. chlorophyll-a £. 0.25 jig L' 1 ; N0 3 ' £. 0.25 jxm; 
NH 4 * £.0.10 jam). P concentrations, however, were often higher offshore. Sediment N 
and P were low and comparable to those of pristine reef areas. Sediment N was higher 
nearshore and decreased offshore; P concentrations varied little or exhibited the 
reverse pattern. Sediment N:P ratios were consistently lower offshore (1-10 vs. 20 
- 40 nearshore) indicating that N may be limiting to offshore algae. Low sediment 
nutrient content suggests that either supply of detrital material to reef tract sediments 
is low, or that remineralization rates are high. Higher offshore P0 4 ' 3 concentrations 
are attributed to periodic up welling along the shelf edge. The second distribution 
pattern was found in the ’middle keys’: Water column nutrients and chlorophyll-a were 
two times those in areas north and west of there. Sediment nutrients were higher also 
but nearshore and offshore areas did not differ. The middle keys are largely devoid of 
patch reefs and the offshore reefs are drowned ca. 5 m or more in depth. The higher 
sediment and nutrient efflux through the wide passes in this area (i.e. Shinn's inimical 
waters) are likely responsible for the lack of Holocene reef growth in this part of the 
Florida Keys. 
1992 . 
Tilmant, J. T., R. W. Curry, R. Jones, A. Szmant, J. C. Zieman, M. Flora, M. B. Robblee, D. 
Smith, R. W. Snow, and H. Wanless (1994) Hurricane Andrew's effect on marine resources. 
BiaScisnse, 44(4):230-7. 
Florida Bay has undergone dramatic changes in its seagrass beds since 1987 due to an 
unexplained seagrass dieoff. Before Hurricane Andrew, the decay of the stabilizing 
rhizome mat had left much of the bay vulnerable to erosion. For several months before 
the storm, bottom sediments had been disturbed and suspended and an area of milky 
green to brown water had persisted over much of the Bay. After Hurricane Andrew, 
the area appeared unchanged. From air and underwater observations, Florida Bay does 
not appear to have been affected directly by the storm. However, we expected eventual 
longer-term alterations to Florida Bay form nutrient increases associated with post¬ 
storm runoff. During the first few weeks after the storm, several reports of massive 
fish kills within the mangrove zone of the Everglades National Park and of an extermely 
strong smell of hydrogen sulfide over the west coast region were made. This suggests 
significant mortality during the storm or in relation to depleted oxygen levels 
associated with organic loading immediately afterward. Four weeks after the storm, no 
evidence of fish kills was found by the authors. Impact of the storm on loggerhead sea 
turtles, crocodile nests and the manatee population was minimal. 
1992 0 
Zieman, J. C., R. Davis, J. W. Fourqurean, and M. B. Robblee (1992) The role of climate in 
the Florida Bay seagrass dieoff. Abs., 1992 Symp. on Florida Keys Regional Ecosystem, 
November 16-20, Miami, FL. Bull. Ecol. Soc. America. , 73(2):398. 
[ABSTRACT ONLY. DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Since the fall 
of 1987, Florida Bay has experienced a major die-off of seagrasses and benthic 
macrophytes totaling tens of thousands of hectares. After several years, dieoff of 
Thalassia continued at a reduced rate, while colonization and growth of the colonizer 
Halodule became widespread. Anomalies in the recent climate record may have played a 
significant part in the dieoff initiation. Retrospective analysis of earlier data coupled 
with current studies show a large increase in seagrass biomass prior to the dieoff and a 
355 
