1988 
Powell, G. V. N., and F. C. Schaffner (1991) Water trapping by seagrasses occupying bank 
habitats in Florida Bay. Est. Coastal Shelf Sci. . 32(1):43-60. 
Seagrasses, largely Thalassia testudinum, occupy habitats atop shallow carbonate 
mudbanks adjoining basins up to 3 m deep in Florida Bay. In this study, the phenomenon 
of water trapping whereby, during low tides, the seagrass meadow matrix retains a 
thin (< 20 cm) layer of water high on the bank top despite water levels in the adjoining 
basins being some 25-70 cm lower. The matrix slows water flow off the banks such 
that changes in the rate at which water recedes through time approximates a sigmoid 
function of water level. A meadow with a large seagrass standing crop (59 g dry mass 
m' 2 ) held a 17.4-cm layer of water atop the bank, while a meadow of lesser standing 
crop (less biomass per area, 130 g dry mass m' 2 ) that may have been facilitated by a 
topographical berm held just 3.3 cm of water. Similarly, on the bank slope the higher 
standing crop meadow held 10.4 cm of water while the bank slope meadow at the site 
with lesser standing crop held only 1.6 cm of water. Water trapping by seagrass can 
keep water on the banks for up to 8 hr during low tides, preventing desiccation of the 
bank, and thereby providing permanent habitat for a diverse community of epibenthic 
fishes and invertebrates. The water trapping phenomenon presumably enhances overall 
prey abundance and diversity, and regulates the temporal patterns of prey exposure to 
different types of predation risk, e.g. to wading birds vs. predatory fishes. This study 
took place in Murray Key and Sandy Key during 1988. 
1988 0 
Quinn, T. M., and D. F. Merriam (1988) Evolution of Florida Bay islands from a supratidal 
precursor: evidence from westernmost Bob Allen Key and Sid Key. J. Geol. . 96(3):375-82. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Cores from the interior portions 
of westernmost Bob Allen Key and Sid Key document island nucleation from a supratidal 
precursor developed on a paralic peat deposit; whereas cores from exterior portions of 
these islands document development of marine mudbanks, progradation or colonization 
by mangroves, and supratidal sedimentation. The supratidal precursor beneath these 
islands consists of eroded remnants of coastal tidal flats or local topographic highs that 
remained supratidal throughout the Holocene sea-level rise. Sedimentologic and 
biostratigraphic evidence suggest erosion of mangroves by storms or inundation of 
mangroves by storm deposits is a common precursor to subsequent sediment 
aggradation on both islands. If other Florida Bay islands developed from mangrove 
colonization of marine mudbanks, then data from westernmost Bob Allen Key and Sid 
Key indicate that nucleation from a supratidal precursor and mangrove colonization of 
marine mudbanks are both viable mechanisms for island initiation. The absence of 
evidence of a supratidal nucleus beneath an island can result from (a) island migration 
and subsequent erosion or (b) insufficient sampling density. Stratigraphic data from 
Florida Bay are insufficient to discriminate between the relative importance of these 
two models of island evolution; we contend that any model of the evolution of Florida 
Bay islands must incorporate island nucleation from a supratidal precursor as a viable 
mechanism for island evolution. 
1988 
Smith, K. N., and W. F. Herrnkind (1992) Predation on early juvenile spiny lobsters 
Panulirus argus (Latreille): influence of size and shelter. J. Exp. Mar. Biol. EcoL 157:3- 
18. 
Juvenile spiny lobsters Panulirus argus (Latreille) from three behaviorally and 
ecologically distinct ontogenetic groups (algal, 5-15 mm carapace length; transitional, 
16-25 mm CL; and post-algal, 26-35 mm CL) were tethered in their characteristic 
shelters and on open substratum to evaluate size related differences in predation risk. 
318 
