Central Gulf Coast Of Florida Research Articles

Exploring the season of mound building through oxygen isotope geochemistry at the Garden Patch site, Gulf Coast Florida, USA

ABSTRACTThe American Southeast saw the development of large ceremonial village centers, the coalescence of households, and monumental architecture integrated into village layout during the Middle Woodland period (ca. AD 1–600). These shifts toward more sedentary lifeways occurred independently of, and prior to, the domestication of plants across the Southeast. This paper examines the seasonality of monumental construction at the Garden Patch site located on the central Gulf Coast of Florida. This site contains evidence for rapid mound construction that followed a predetermined site plan. Here, we present oxygen isotope analyses of archaeological mollusk shells (Crassostrea virginica) to evaluate the seasonality and periodicity of monument construction. We conclude that mound construction occurred during the cooler months of the year. Ultimately, this contributes to an anthropological understanding of the development of these early ceremonial centers in the Southeast.

Evidence for Stepped Pyramids of Shell in the Woodland Period of Eastern North America

AbstractAntiquarians of the nineteenth century referred to the largest monumental constructions in eastern North America as pyramids, but this usage faded among archaeologists by the mid-twentieth century. Pauketat (2007) has reintroduced the term pyramid to describe the larger, Mississippian-period (A.D. 1050 to 1550) mounds of the interior of the continent, recognizing recent studies that demonstrate the complexity of their construction. Such recognition is lacking for earlier mounds and for those constructed of shell. We describe the recent identification of stepped pyramids of shell from the Roberts Island Complex, located on the central Gulf Coast of Florida and dating to the terminal Late Woodland period, A.D. 800 to 1050, thus recognizing the sophistication of monument construction in an earlier time frame, using a different construction material, and taking an alternative form.

Assessing village life and monument construction (cal. AD 65–1070) along the central Gulf Coast of Florida through stable isotope geochemistry

Given recent debates and reinterpretation of large-scale shell deposits as monuments rather than midden in the emerging dialogue in world archaeology regarding shell sites, we need better quantitative assessments of the temporality of shell deposit formation. Here we couple Bayesian analysis of radiocarbon dates with the results from our study of shell isotopes from C. virginica from the Crystal River and the Roberts Island Shell Mound Complex, neighboring and temporally overlapping shell mound sites on the central Gulf Coast of Florida. Linking these two lines of data is a new methodological approach which provides a more detailed understanding of the temporality of traditions. The results indicate that midden accumulation occurred throughout the year in the later phases of occupation at both sites. In contrast, oyster from mound deposits appears to indicate season of collection predominately during the colder months of the year. This contrast between mound and midden season of collection suggests that episodes of feasting and associated monument construction may have been of relatively limited temporal duration.

Comparison of Small-Mammal Sampling Techniques in Tidal Salt Marshes of the Central Gulf Coast of Florida

Use of traditional small-mammal sampling techniques is challenging in coastal salt marshes and forests. Various conditions particular to this type of environment affect the efficacy of sampling efforts. We compared various indirect (no physical capture) and direct (physical capture) techniques coupled with different baits to determine an effective method for sampling small mammals. In 1440 trap-nights, Sherman live traps caught significantly more rodents than Fitch traps (112 versus 16 respectively, Fisher's exact test: P = 0.0103), but the relationship between bait types, which included oats, scratch feed, sunflower seeds and suet, was not as apparent. However, for practical reasons, scratch feed and sunflower seeds were best used in marsh conditions due to their water resistance and ease in clean-up. Both track and scat plates were unsuccessful due to water damage and destruction by nontarget animals. Cameras yielded limited success. Target small mammals were photographed 436 times, but of those, only 26 could be positively identified to species. However, with adjustments including improved lens quality and adjustable focus distance, this could become a useful tool for small-mammal sampling. Such improved remote cameras could offer a viable alternative when permits cannot be issued, field access is limited, or there are concerns about mortality of the target species.

Comparison of Small-Mammal Sampling Techniques in Tidal Salt Marshes of the Central Gulf Coast of Florida

Abstract Use of traditional small-mammal sampling techniques is challenging in coastal salt marshes and forests. Various conditions particular to this type of environment affect the efficacy of sampling efforts. We compared various indirect (no physical capture) and direct (physical capture) techniques coupled with different baits to determine an effective method for sampling small mammals. In 1440 trap-nights, Sherman live traps caught significantly more rodents than Fitch traps (112 versus 16 respectively, Fisher's exact test: P = 0.0103), but the relationship between bait types, which included oats, scratch feed, sunflower seeds and suet, was not as apparent. However, for practical reasons, scratch feed and sunflower seeds were best used in marsh conditions due to their water resistance and ease in clean-up. Both track and scat plates were unsuccessful due to water damage and destruction by nontarget animals. Cameras yielded limited success. Target small mammals were photographed 436 times, but of thos...

The Persistence of Endangered Florida Salt Marsh Voles in Salt Marshes of the Central Florida Gulf Coast

Abstract Two endangered Microtus pennsylvanicus dukecampbelli (Florida Salt Marsh Vole) were captured at a new location, in February of 2009, at Lower Suwannee National Wildlife Refuge. Since the species discovery in 1979, only 43 Florida Salt Marsh Voles (hereafter FSM Vole) have been captured. Outside of the type locality, this is only the second documented location for the FSM Vole. Given the difficulty in trapping this species and the lack of information about its life history, its discovery in a new location lends itself to the possibility that it is more widespread in the Central Florida Gulf Coast than previously thought. Although much of the salt marsh in the area is in public ownership, a good deal of it has already been altered by logging or development and is threatened by global climate change. More research is needed to adequately protect and manage the habitat for the FSM Vole. A study of FSM Vole coastal salt marsh habitat could also serve as a valuable monitoring tool for subtle changes in...

Analysis of Sediment and Gut Contents of the Sand Dollars Mellita tenuis, Encope michelini, and Encope aberrans off the Central Florida Gulf Coast

Sand dollars are conspicuous macroinvertebrates on particulate substrates in intertidal and shallow water environments. Their locomotion and feeding can have major effects on the sediment and infauna. We investigated the sediment and gut contents of three species of sand dollars off the central Florida gulf coast. Sediment comprised quartz particles at two sites and mixed quartz particles and carbonate shell hash at the third site. At all sites, gut particles were smaller than those of the sediment. This could have been the result of the teeth of the Aristotle’s lantern crushing the particles. However, particles in the food grooves of two species (Mellita tenuis and Encope michelini) were similar to those in the gut contents, smaller than in the sediment. This indicates that selection for small particles from the sediment occurred and that crushing of particles was not necessary to account for the small size of particles in the gut for those collections. The concentration of organic matter in the gut contents was much greater than that of the sediment, indicating that selection of organic matter not associated with the inorganic sediment particles occurred. It is possible that the contribution of organic matter not associated with the inorganic sediment particles is of considerable importance to the nutrient requirements of the sand dollars.

Red-tide–associated Mass Mortality in 2005 of the Sand Dollars Encope aberrans, Encope michelini, and Mellita tenuis (Echinodermata: Echinoidea) on the Central Florida Gulf Coast Shelf

In March 2005, populations of Encope aberrans and E. michelini found at 20-m depth (ca. 27 km west of Captiva Island) and of Mellita tenuis at 6.5-m depth (ca. 7 km west of Egmont Key) were studied to calculate density and size frequency distribution. All individuals were alive. A red tide occurred on the central Florida Gulf Coast shelf during the summer. In Sept., all individuals in these populations were dead. Dead individuals had lost their spines and were gray but intact, indicating recent death. On the same date, all E. michelini and E. aberrans were alive in a population at 20-m depth (ca. 26 km north of the site off Captiva Island and ca. 23 km west of Gasparilla Island). All individuals in a population of M. tenuis at 2-m depth immediately offshore Fort De Soto Park were alive 1 mo after the observation of complete mortality off Egmont Key. All E. aberrans at a site 28 km southwest of Egmont Key were dead in Oct. In May 2006, live E. michelini occurred at the Captiva site at the same density as in March and Sept. 2005. Their large size indicates their origin was by migration from nearby areas unaffected by the red tide.

Diets and coexistence of the sea urchins Lytechinus variegatus and Arbacia punctulata (Echinodermata) along the central Florida gulf coast

The basis for coexistence of similar species is fundamental in community ecology. One mechanism for coexistence is differentiation of diets. Lytechinus variegatus and Arbacia punctulata coexist in different microhabitats along the Florida gulf coast. Their great difference in morphology might affect their choice of microhabitats and diet. We analyzed diets of both species at 1 offshore and 1 nearshore site where both occurred in relatively equal numbers, an offshore site dominated by A. punctulata and an offshore site dominated by L. variegatus. Gut contents were analyzed to deter- mine the diet. A. punctulata prim. consumed sessile invertebrates except on dates when algal avail- ability was higher than normal. L. variegatus primarily consumed macroflora except on dates when macroflora was extremely limited. Electivity indices revealed no strong preferences for particular species of algae, although L. variegatus consumed many drift species. A. punctulata and L. variega- tus both fed in a random manner, although they avoided particular species of algae known to contain high concentrations of secondary metabolites. The diet of A. punctulata was correlated with algae only over rubble outcroppings at the offshore site with the highest biomass. Diets of offshore popula- tions were more similar to each other, regardless of the presence of conspecifics, than to those of populations at Caspersen Beach (nearshore site). As diets do not overlap, distribution of individuals at a location would not be affected by interspecific competition for food. However, intraspecific competition may be high due to low site productivity.

Vegetative characteristics of three low-lying Florida coastal rivers in relation to flow, light, salinity and nutrients

The Chassahowitzka, Homosassa and Crystal rivers along the central Gulf coast of Florida were studied from 1998 to 2000 to identify factors controlling the abundance and distribution of submersed aquatic vegetation (SAV). Each of these three low-lying coastal rivers are spring-fed and exhibit low to moderate absolute flow rates (flows in either direction because of tidal influences, 0.06–0.46 m s−1) with only 14 of the stations sampled for SAV having flow rates in excess of 0.25 m s−1. At those stations where flow rates exceeded 0.25 m s−1, the substrate was generally comprised of exposed limestone outcroppings and did not provide a favorable habitat for either submersed macrophytes or macroalgae. The remaining sampling stations, where flow rates were less than 0.25 m s−1, had suitable substrates (e.g. mud, mud/sand, and sand) for the colonization and subsequent growth of SAV. Light availability and salinity were determined to be major factors affecting the distribution and abundance of SAV. Sampling stations, where the percent of incident light at the surface reaching the substrate was less than 10, had little or no SAV biomass. Low SAV biomass was also linked to sites where annual average salinities exceeded 3.5‰. Nutrient loads and nutrient concentrations accounted for little variance in SAV biomass after accounting for flow and related substrate type, light and salinity. These latter factors control the distribution and abundance of SAV in these three Florida coastal rivers.

Growth Bands in Test Plates of the Sea Urchins Arbacia punctulata and Lytechinus variegatus (Echinodermata) on the Central Florida Gulf Coast Shelf

Growth bands in test plates provide information about the biology and ecology of sea urchins. We documented the bands in the test plates of Arbacia punctulata and Lytechinus variegatus at different seasons and locations on the central Florida Gulf Coast shelf. The number of growth bands in test plates is significantly correlated with test diameter for A. punctulata. The number of growth bands is not significantly correlated with test diameter for L. variegatus. The condition of the outermost growth band was recorded along with the month and reproductive state to investigate the effect of variation in reproduction and temperature on growth. Growth bands in A. punctulata are well defined and appear to be related to the reproductive cycle. Growth bands in L. variegatus are less well defined and may be more closely related to food availability.

Comparative patterns of occupancy by decapod crustaceans in seagrass, oyster, and marsh-edge habitats in a Northeast Gulf of Mexico estuary

Decapod crustaceans occupying seagrass, salt marsh edge, and oyster habitats within the St. Martins Aquatic Preserve along the central Gulf coast of Florida were quantitatively sampled using a 1-m2 throw trap during July–August 1999 and March–April 2000. Relative abundance and biomass were used as the primary measures to compare patterns of occupancy among the three habitat types. Representative assemblages of abundant and common species from each habitat were compared using Schoener's Percent Similarity Index (PSI). In all, 17,985 decapods were sampled, representing 14 families and 28 species. In the summer sampling period, mean decapod density did not differ between oyster and seagrass habitats, which both held greater densities of decapods than marsh-edge. In the spring sampling period oyster reef habitat supported greater mean decapod density than both seagrass and marsh-edge, which had similar densities of decapods. Habitat-specific comparisons of decapod density between the two sampling periods indicated no clear seasonal effect. In summer 1999, when seagrasses were well established, decapod biomass among the three habitats was not significantly different. During spring 2000, decapod biomass in oyster (41.40 gm−2) was greater than in marshedge (4.20 gm−2), but did not differ from that of seagrass (9.73 g m−2). There was no significant difference in decapod biomas between seagrass and marsh-edge habitats during the spring 2000 sampling period. The assemblage analysis using Schoener's PSI indicated that decapod assemblages associated with oyster were distinct from seagrass and marshedge habitats (which were similar). The results of this study suggest that in comparison to seagrass and marsh-edge habitats, oyster reef habitats and the distinct assemblage of decapod crustaceans that they support represent an ecologically important component of this estuarine system.

Seasonal and Spatial Variation in Algal Composition and Biomass on the Central Florida Gulf Coast Shelf

Information on primary producers is fundamental to the understanding of communities. Little is known about the primary producers of marine communities at intermediate depths on the Florida Gulf Coast shelf. The diversity and biomass of algae and seagrass were studied seasonally at three offshore sites (12- to 18-m depth) and one nearshore site (6-m depth) on the central Florida Gulf Coast shelf. Thirty-eight species of attached and drift macroalgae and one drifting seagrass, Thalassia testudinum, were found. The deepest collection site was the most productive in terms of standing biomass and had much more flora on limestone rubble than on sand. All other sites had relatively low floral biomass. Algal diversity varied considerably with season at 6- and 12-m depths, whereas a more stable diversity was observed at 18m. Plant and algal communities in the Gulf of Mexico vary greatly between sites of different depths even when in close proximity. Intermediate depths contained lower algal biomass with more variable species composition over time than the deeper offshore sites.

Specific‐Gravity Effects on Fertilizer Leaching from Surface Sources to Shallow Water Tables

AbstractSubirrigated sands with surface‐applied fertilizer bands are susceptible to considerable gravity‐induced convection of fertilizer salts whenever the water table approaches within 30 to 45 cm of the soil surface and induces rapid fertilizer dissolution. Laboratory studies have been conducted on two sands from Manatee County in the vegetable and citrus production region along central Florida's Gulf Coast. Peak saturated‐zone electrical conductivity (EC) values of 14 and 9 dS m−1 were attained within 3 to 5 d at the 60‐cm depth for columns of local sand having a water table maintained 2.5 and 22.5 cm below the soil surface, respectively. Such movement is far too rapid to be ascribed to reasonable diffusional or traditional convective‐flow effects, and is instead attributed to gravity‐induced convective flow, or fertilizer “dropout”. Sectioned‐column studies demonstrated near‐surface EC values of 25 to 35 and 70 to 90 dS m−1 for water tables maintained at the 15‐ and 45‐cm depths, respectively. These same columns evidenced solute‐pulse movement to the 8‐ to 10‐cm depth and the 15‐ to 20‐cm depth after 6 and 24 h, respectively, for water tables maintained at the 45‐cm depth. Lower hydraulic conductivity, quite possibly as a result of increased soil organic matter content for these otherwise virtually identical fine sands, moderated such effects somewhat. Implications are discussed with respect to early‐season fertilizer management in vegetable production regions of the southeastern Coastal Plain.

Ground Stabilization for foundation and excavation construction in Florida karst topography

The construction of additional facilities at the Florida Power Corporation's Crystal River Energy Complex required an extensive stabilization program to construct foundations for approximately one half mile of cooling towers. This paper presents an overview of the techniques and methods used in the construction of additional facilities at the Crystal River Generating Station. Excavations for intake and discharge structures were to be more than 20 ft below the water table. Cooling tower foundations were constructed on extensively solutioned Florida limerock located on the central Gulf Coast of Florida. Hybrid ground modification techniques were used to stabilize soft or loose soils and solution features in the underlying limerock, allowing mat and spread footing foundations to be used for most of the facility. The ground modification techniques were used to detect, collapse, densify, and fill solution features below the structure foundations. The bearing capacity after ground modification was verified by field load tests. Subsurface investigations indicated that sheet pile excavations with grouted seals were the optimal technique for cofferdam excavations in the limerock formation. Existing collapsed caverns were encountered during construction of the cofferdam for the intake structure and the adjacent discharge structure, requiring a fast-track design change, considerable field coordination, and daily modifications to accommodate the varied conditions encountered. Tied-back soldier pile cofferdam construction was combined with grouting, underwater excavation, and a massive, unreinforced, concrete tremie slab with grouted anchors, and installed off a barge to provide a dewatered excavation. This project involved the use of hybrid soil-rock anchors to anchor one of the largest continuous placement tremie seals installed in Florida. Other excavations used sheeting and grouting of the underlying limerock formation to provide a dewatered excavation. Ground modification techniques were used to treat a filled cavern discovered in the corner of one discharge structure. The entire construction of this facility was confined to a narrow work area by existing wetlands and the generating station discharge canal. Strict environmental restrictions required by the regulatory agencies to prevent impacts to the surrounding area were imposed on this project.

Stratigraphy and Geologic History of Central Florida Gulf Coast Barrier Island: ABSTRACT

Stratigraphy and Geologic History of Central Florida Gulf Coast Barrier Island: ABSTRACT