primarily on crustaceans (amphipods and isopods) and vegetation (marine 
alga/seagrasses), whereas resident species exhibited carnivorous feeding habits, 
consuming mainly crustaceans (amphipods and shrimp), polychaetes, and mollusks 
(bivalves). Spatial, temporal, and ontogenetic variations in foods habits were found 
among the species sampled. Shrimp exhibited dramatic differences in diet with predator 
size, site, and season; highest feeding activity was found in the fall-winter period 
while feeding diversity was lowest at the inner-most sampling site (Tarpon Bay). 
Silver jenny diet varied with season and site, while pinfish varied by season and size 
and pigfish by predator size. Variations in diet with site and season were attributed to 
food availability and habitat structure while trophic ontogeny was related to 
fish/shrimp morphogenesis. These species were sufficiently opportunistic in their food 
habits to take advantage of the availability of major prey groups found at the sampled 
sites. In summary, variations in abundance of the dominant species among sites were 
related to feeding habits as a reflection of prey availability and vegetative cover, while 
recruitment and reproductive activity were associated with season effects. It may be 
that patterns of estuarine abundance, as reported in this study, are influenced by 
long-term evolutionary adaption than by short-term ecological or behavioral response 
to environmental parameters. 
1979 - 1981 
Brown, J. W. (1987) Studies of humic and fulvic acid dynamics in coastal marine waters of 
South Florida. Mar. Environ. Res. . 21:163-74. 
Humic (HA) and fulvic (FA) acid concentrations (HA + FA) were monitored over a two- 
year period in different areas of Florida and Biscayne Bays. The Florida Bay sampling 
site was north of Islamorada. These studies were undertaken in an effort to determine 
fluctuations in the quantity and chemical nature of humic substances in productive 
coastal environments in South Florida and, retrospectively, to discern the extent of 
potential terrestrial influences. Additional studies were undertaken with material from 
a South Florida mangrove environment and material isolated from offshore Gulf Stream 
waters. Dramatic fluctuations in humic substances were observed in all coastal areas. 
In east-central Florida Bay, for example, humic materials (HA + FA, collectively) were 
found to fluctuate as much as eleven fold. In both Biscayne Bay and Florida Bay, these 
fluctuations appeared to follow the artificially-controlled input to water from the South 
Florida mainland. The ratios of FA to HA varied dramatically between terrestrially- 
influenced and oligotrophic marine environments (i.e. a progressive increase of the 
FA/HA ratio with this transition). In all marine locations studied, coarse particulate 
humic substances were low in comparison to the dissolved component of this chemical 
class. The sampling sites were monitored at 6 - 8 week intervals during 1979 to 1981. 
1980 0 
Aisner, J. A. (1980) Origin and development of Arsenic Bank, a Holocene biotherm in 
southwestern Florida Bay. Geol. Soc. Amer. Abs. . 12(4): 169. 
[ABSTRACT ONLY. DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Arsenic Bank is 
a Holocene biotherm located in southwestern Florida Bay, approximately 9 km north- 
northwest of Long Key. Fourteen cores were analyzed to determine the stratigraphy 
and depositional process of the shoal. Sediment samples from the shoal surface were 
also analyzed to determine recent modes of sedimentation and biotic communities. 
Arsenic Bank is composed of alternating beds of coarse coral, algal and molluscan 
sediments with subordinate plant, foraminiferal and ostracode debris. A thick carpet of 
Thalassia, Porites, Halimeda and sponges blankets the shoal and allows for sediment 
entrapment, shoal growth and stability. These current and wave resistant organisms 
form a loose, interlocking framework where coarse-grained molluscan and Halimeda 
sediment is entrapped. Sediment texture suggests that the various modes of 
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