Field experiments performed during 1988 at two sites near Long Key, Florida Bay 
nursery habitat indicated that juveniles attained a partial size refuge from a suite of 
abundant algal lobster predators at about the time they emerged from settling habitat. 
Algal lobsters experience significantly decreased mortality by sheltering at night, 
thereby attaining a survival rate comparable to that of larger, older juveniles that 
forage nocturnally in the open. Diver surveys and limited net sampling revealed an 
array of lobster predators including octopus, portunid crabs, bonnethead sharks, nurse 
sharks, sting rays, gray snapper and toad fish, as well as general crustacean predators 
including bonefish and permit. High relative mortality of the smallest juveniles suggests 
that predation on the algal and early transitional phases was a potential bottleneck to 
population recruitment. 
1988, 1990 
Rude, P. D., and R. C. Aller (1991) Fluorine mobility during early diagenesis of carbonate 
sediment; an indicator of mineral transformations. Geochim. .Cosmochim. A. . 55(9)2491- 
509. 
The abundant occurrence of calcium carbonate minerals in marine sediment, their well- 
documented dissolution or precipitation during diagenesis, and their high F content 
suggest that carbonate mineral diagenesis may be an important influence on F behavior 
in marine sediment. To test this hypothesis, the geochemistry of F in shallow carbonate 
mudbank sediment of Florida Bay was examined. The F content of biogenic calcium 
carbonate in Florida Bay varies with mineralogy, positively correlates with the Mg 
content of calcite, and occurs in similar abundance to Sr (high-Mg calcite: F/Sr = 2.4 
mol/mol; aragonite: 0.53-0.79 mol mol' 1 ; low-Mg calcite: 0.22 mol mol' 1 . Models of 
porewater distributions, direct solute flux measurements, and reaction rate estimates 
over the upper 0 - 16 cm of sediment from Bob Allen Key Bank predict net fluxes out of 
the sediment of 170 nmol F m^d' 1 , 230 nmol Sr m^d* 1 , and 5.6 mmol Ca m' 2 d* 1 . The 
net solute flux ratio of F/Sr (0.71 mol mol' 1 ) is consistent with dissolution of aragonite 
or high-Mg calcite, but F/Ca and Sr/Ca ratios (28 mmol mol' 1 and 40 mmol mol' 1 , 
respectively) are 3-10 times that of biogenic carbonate sources. Selective dissolution 
of a high F and Sr content phase or, more likely (based on dissolution experiments), 
concurrent dissolution and reprecipitation of phases with different F and Sr contents 
account for this discrepancy. The loss of F, Sr, and Ca to fluorapatite precipitation, as 
predicted from a stoichiometric model of phosphate release, can be added to the 
transport reaction model predicted net fluxes. A resulting, more complete mass balance 
model incorporating both carbonate mineral reactions and fluorapatite formation yields 
total release estimates of F, Sr, and Ca of 770 nmol, 332 nmol, and 53 mmol nr 2 d' 1 , 
respectively. Calcium carbonate minerals apparently undergo transformation whereby 
34 mmol high-Mg calcite m' 2 d' 1 and 19 mmol aragonite rrr 2 d' 1 dissolve, and 46 mmol 
low-Mg calcite m' 2 d' 1 precipitates (ignoring other cations besides Ca). If no 
fluorapatite formation occurs, the required fluxes are that 23 mmol aragonite m' 2 d' 1 
dissolves and 3.4 mmol high-Mg calcite m' 2 d' 1 and 14 mmol low-Mg calcite m' 2 d' 1 
precipitate. Net loss of CaC0 3 from the deposit by dissolution is 6-7 mmol nrr 2 d' 1 (3% 
of the accumulation flux). The magnitude of these fluxes could cause significant 
mineralogical and chemical changes on rapid time scales in nearshore carbonate 
sediment. Fluorine is probably mobile in other carbonate deposits undergoing diagenetic 
alteration on short and longer time scales and is a powerful additional constraint on the 
rates and nature of carbonate mineral diagenesis. Sample collection for this study took 
place during 1988 and 1990. 
1988 - 1989 
Forcucci, D., M. J. Butler, and J. H. Hunt (1994) Population dynamics of juvenile Caribbean 
spiny lobster, Panulirus argus, in Florida Bay, Florida. Bull. Mar, Sci, . 54(3):805-18. 
319 
