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Differentiation of continental shelf morphology along the southeast Florida Atlantic coast was based on interpretation of airborne laser bathymetry. The 600-km2 shelf study area, which had a shoreline extent of about 160 km and extended up to 10 km offshore, displayed a diverse range of seafloor morphologies that were characteristic of four main alongshore reaches. Reach I (sand flats and karst topography) in the northern part of the study area is terminated southward by the Bahamas Fracture Zone, a major morphotectonic feature. Reach II (sand flats and coral reefs) is characterized by sand flats with diabathic channel fields leeward or shoreward of the Florida Reef Tract, the seaward margin of which occurs along the shelf break on the upper part of the continental slope. Reach III (sand flats, hardgrounds, and coral reefs) is characterized by extensive nearshore rock outcrops that are exposed as bare rock surfaces on the seafloor or are variously mantled by thin veneers of sand that are not thick enough to disguise the underlying rock structure. Reach IV (tidal sand flats and ridges, hardgrounds, and coral reefs) is dominated by tidal features that notably include fields of tidal sand ridges in the lee of the Florida Reef Tract. The barrier reef on the southeast Florida Atlantic coast, which transitions to Florida Keys shelf environments southward, grades northward to drowned karst topography that is overlain by sand sheets and sand waves. Tidal channels and associated bars, deltas, and shoals occur on the interface between Biscayne Bay and the Atlantic Ocean. This reconnaissance-level characterization of continental shelf environments into morphological reaches in a geographic information system platform provides a basis for quantifying spatial distribution patterns of discrete landform units. [ABSTRACT FROM AUTHOR]

Land use changes have been shown to alter the balance of nutrient and mineral sources and sinks to coastal systems. These shifts are often preserved in sediment records. In Apalachicola Bay, productivity is dependent on nutrient loading from the Apalachicola-Chattahoochee-Flint (ACF) river basin; alterations to ACF watershed flow by management activities coupled with increased marine water inundation associated with rising sea level threaten this productivity. The objective of this research was to evaluate past changes in nutrient loading to Apalachicola Bay as recorded in sediment history and determine if these changes could be associated with both anthropogenic and natural alterations in the system. Sediment cores from three sites in the bay were collected and analyzed for organic carbon (C), total nitrogen (N), and total phosphorus (P) concentrations and δ13C and δ15N stable isotopic abundances. The three sites are located at the river mouth (S1), mid-bay (S2), and in the northeastern region of the bay (S3). Carbon and nitrogen concentrations, ratios, and stable isotopes coupled with grain-size shifts for the bay suggest a decrease in river organic matter supply and a change in sediment clay content supply and/or distribution for the bay. Overall, the applied indicators suggest an increase in marine influence on the organic matter in the estuary. These shifts appear to be associated with Apalachicola River management practices coupled with sea-level rise in the Gulf of Mexico. [ABSTRACT FROM AUTHOR]

This article discusses the damage to seagrass beds from boats in a Florida Park from the perspective of bioeconomics. At Lignumvitae Key Submerged Land Managed Area they estimate the value of the seagrass beds based on EPA restoration experience. According to the authors, the size of the boats inflicting damage had more impact on the severity of the damage than the amount of damage. They recommend signage as a cost effective way to reduce harm to the seagrass beds and increased numbers of law enforcement officials depending on the size of the area which needs to recover.

Heavy-metal pollution is an issue of concern in estuaries influenced by agriculture, urban, and harbor activities. Foraminiferal assemblages have been shown to be effective indicators of pollution. Sediment samples (n = 110) from Biscayne Bay were analyzed for heavy metals, foraminiferal assemblages, and grain-size distribution. Highest Cu, Zn, Cr, Hg, Pb, and Ni concentrations were found closest to Miami and near the mouths of several canals along the western margin of the bay. Few samples exceeded limits of possible biological effects as defined by previous studies. Ammonia and Cribroelphidium, two known stress-tolerant genera, correlated positively with Cu, Zn, Hg, and Ni (r ≥ 0.43). Symbiont-bearing foraminifers, Archaias, Laevipeneroplis, and Androsina, correlated negatively with Cu, Zn, Hg, and Ni (r ≤ -0.26). [ABSTRACT FROM AUTHOR]

Dissolved constituent fluxes from the sediment to the water column are important in estuarine environments. Benthic nutrient source depends on the mechanisms driving advection, the advective transport rate, and the concentration of nutrients in the discharged water, all of which depend on the source of discharged water and water-solid reactions along its flow. Pore water advection has been measured at rates of 3 to 6 cm/d using seepage meters in the Banana River Lagoon, Florida. Diffusion, advection, and reaction modeling of SiO2 profiles in pore water indicate that advection and reactions are more important than diffusion in the upper 1 m of the sediments. Advection results from the recirculation of the overlying water column through the bottom sediments, oxygenating the lagoon water, while pore water lacks oxygen. As lagoon water recirculates through sediments, the subsequent loss of oxygen enhances regeneration of buried organic matter. Using measured seepage rates and average pore water concentrations of nutrients, N and P fluxes from the sediment are estimated to be 33 to 38 µg/cm²/y and 3 to 5 µg/cm²/y, respectively. On the basis of sedimentation rates and the average concentrations of N and P in the sediment, the fluxes of N and P to the sediment are estimated to be 9 to 38 µg/cm²/y and 2 to 6 µg/cm²/y, respectively. These values suggest that 100% more N and 30% more P may discharge with recirculating lagoon water than is deposited in the sediment. Because the source of most pore water is surface water, the excess nutrients appear to originate from organic matter regeneration at or near the sediment-water interface, thereby elevating their concentrations in pore waters and depleting their concentration in the buried sediment. This regeneration of nutrients appears to limit their burial rate in the lagoon. [ABSTRACT FROM AUTHOR]

Marsh surface deposition, suspended sediment concentrations, tidal hydrodynamics, and marsh surface characteristics were measured within a tidal creek system of a west-central Florida, microtidal, open marine Juncus roemerianus marsh to examine the depositional relationship between a creek system and the surrounding marsh during nonstorm conditions. Results suggest that short-term marsh deposition is highly episodic with deposition showing an inverse relationship with marsh surface inundation. Deposition was greatest at marsh sites adjacent to secondary creek segments over all examined timescales. Variations in hydroperiod, time-velocity asymmetry, vegetation density, and sediment availability could not explain the observed differences in short-term deposition. [ABSTRACT FROM AUTHOR]

Beach nourishment requires large volumes of sand from offshore and new sources are constantly sought for development. The sediment-starved continental shelf off the central-west coast of Florida has traditionally supplied beach-quality sediments from ebb-tidal shoals and nearshore sand sheets, but as these supplies dwindle, sand searches increasingly look farther offshore for resources. Widely spaced sediment ridges, interspersed by karstified limestone seafloor (hard grounds), offer potential as sand resources that can be exploited by dredging to renourish eroded beaches for shore protection. The sand ridges, late Holocene in age, are generally shoreface detached, sediment starved, and clustered in "ridge fields." Six sediment ridge fields identified along 285 km of coast (Anclote, Sand Key, Sarasota, Manasota, Captiva, and Collier) contain about 1.4 billion cubic meters of sediments that are potentially available for dredging. Evaluation of these sediment sources, within the purview of the USMinval Code, requires the determination of resources, reserves, and level of certainty of assessment applied to a rating of resource potential. Present research is attempting to identify the overall resource potential with an eye toward eventually determining sand volumes in reserves, which will be much less than the total sand resource volume. [ABSTRACT FROM AUTHOR]

Beach erosion, a problem along most sandy shores, can be caused by man-induced interventions to the coast or natural processes. Remediation of beach erosion (i.e., beach restoration) along eroding developed beachfronts is commonly practiced in the United States by periodic beach renourishment with or without coastal structures. Rates of erosion within beach fills generally vary greatly, and areas that erode faster than the nourishment average are commonly termed erosional hot spots (EHSs). Delray Beach, located on the southeast coast of Florida, was renourished for the fourth time on December of 1992 with about 914,000 m³ of sand dredged from offshore and placed along 2.7 km of beach. About 448,000 m³ of the fill had eroded away by 2001, about eight and a half years after initial construction. Two beach segments with erosion rates higher than the nourishment average were identified based on analysis of annual beach profile data. About 40% of the eroded volume accrued from one of these beach segments, a 600-m long EHS located on the downdrift end of the nourishment. We evaluated hypotheses to explain EHS development; these included the influence of nearshore features (reefs and borrows) on nearshore wave propagation, variability of grain size alongshore, and changes in shoreline orientation induced by the placement of fill. The nearshore reefs have little to negligible influence on the nearshore waves and are not the cause of the EHSs. Borrow areas significantly influence nearshore waves along the beach. Grain-size differences alongshore were also not the cause of increased erosion of EHS segments since grain sizes are not persistently finer where higher erosion is observed or vice versa. Change in shoreline orientation in the south end of the fill (EHS segment) causes an acceleration of the alongshore currents and an increase in sediment transport potential. Shoreline orientation effects appear to play a relatively more significant role in the development of the EHS in the south end of the fill than the other processes evaluated. [ABSTRACT FROM AUTHOR]

Ivan, a strong Category 4 hurricane (downgraded to a Category 3 at landfall), caused widespread erosion and overwash along the northwestern Florida barrier-island beaches. This study examines the storm impact and short-term poststorm recovery along a 200-km stretch of coast from Fort Walton Beach eastward to St. George Island. One prestorm and three poststorm beach-profile surveys were conducted to quantify the storm-induced morphological changes and poststorm recovery. Forty-six trenches were excavated to study the characteristics and thickness of subaerial storm deposits. Extensive inundation and overwash occurred within 100 km from the storm center at landfall. Significant beach/dune erosion was measured as far as 300 km east of the storm center. The highest elevation of beach erosion extended considerably above the measured storm-surge level, indicating that storm-wave setup and swash run-up played significant roles in controlling the elevation of beach erosion. A simple empirical formula reproduced the wave setup and swash run-up reasonably well. Beach recovery began immediately after the storm. Within 90 days, the berm crest recovered to its prestorm elevation, although it was now located approximately 15 m landward for nonoverwashed sites and 30 to 40 m for overwashed sites. The steep prestorm foreshore slope was restored from the gentle storm profile within 30 days. An apparent erosional surface was observed along the impacted foredune and backbeach, extending over 300 km eastward from the storm center. This erosional surface represents a net elevation loss ranging from 0.5 to over 2.0 m. A storm layer of up to 50 cm thick was deposited above the erosional surface. Generally, the storm-layer thickness decreases away from the storm center, as well as landward from the high tide line. Local factors such as beach width and orientation, and sediment properties and supply caused variations in the thickness of storm deposit. [ABSTRACT FROM AUTHOR]

Five asymmetrical, discontinuous, stratigraphically successive Pleistocene reef tracts rim the windward platform margin off the Florida Keys. Built of large head corals, the reefs are imposing in relief (~30 m high by 1 km wide), as measured from seismic profiles. Well dated to marine oxygen isotope substages 5c, 5b, and 5a, corals at depth are inferred to date to the Stage 6/5 transition. The size of these reefs attests to late Pleistocene conditions that repeatedly induced vigorous and sustained coral growth. In contrast, the setting today, linked to Florida Bay and the Gulf of Mexico, is generally deemed marginal for reef accretion. Incursion onto the reef tract of waters that contain seasonally inconsistent temperature, salinity, turbidity, and nutrient content impedes coral growth. Fluctuating sea level and consequent settings controlled deposition. The primary dynamic was position of eustatic zeniths relative to regional topographic elevations. Sea level during the past 150 ka reached a maximum of ~10.6 m higher than at present ~125 ka, which gave rise to an inland coral reef (Key Largo Limestone) and ooid complex (Miami Limestone) during isotope substage Se. These formations now form the Florida Keys and a bedrock ridge beneath The Quicksands (Gulf of Mexico). High-precision radiometric ages and depths of dated corals indicate subsequent apices remained ~15 to 9 m, respectively, below present sea level. Those peaks provided accommodation space sufficient for vertical reef growth yet exposed a broad landmass landward of the reefs for >100 ka. With time, space, lack of bay waters, and protection from the Gulf of Mexico, corals thrived in clear oceanic waters of the Gulf Stream, the only waters to reach them. [ABSTRACT FROM AUTHOR]

A ground-water model was developed for Miami-Dade County Florida, which lies within the Southeast Atlantic Coastal Zone, as a predictive tool that will be used to analyze different water-management scenarios, including regional water-supply plans and the Comprehensive Everglades Restoration Plan (CERP). The model is being developed by the South Florida Water Management District (SFWMD) based on a modified version of the US Geological Survey modular three-dimensional, finite-difference, ground-water-flow model (MODFLOW). This version includes the Wetland and Diversion packages, which are MODFLOW modules that enable the top layer of the grid system to include overland flow through dense vegetation, channel flow through a slough network, and interaction with levees, and thus can closely simulate the natural system. The model domain is discretized into 430 rows by 367 columns with a uniform cell size of 500 ft × 500 ft (152.4 m). Four horizontal layers are used to represent lithologic zones within the surficial aquifer, one of the most transmissive aquifers in the world, with transmissivity values as high as 300,000 ft²/d (27,870.9 m²/d). Boundary conditions were established by water levels in canals on the northern and southern edges of the modeled region and by water-level measurements in wetlands along the western edge. The eastern boundary with the Atlantic Ocean was determined by using mean tidal fluctuations to calculate the equivalent fresh-water head. The main advantage of this model, besides the high degree of detail and the number of variables, is that it can simulate hydroperiods within wetland areas using the Wetland and Diversion packages. These packages allow the model to represent the full hydrologic cycle within the wetland areas, including sources and sinks on a daily basis, starting with total precipitation as a driving force. During calibration (1988–90), a very low sensitivity to conductivity and canal conductances was observed. Therefore, the fit between the model-computed water levels and the observed historical ground-water levels was achieved mainly by adjusting general head boundary conditions and wetland parameters within the active domain. The model is highly sensitive to the operational rules, especially the stages at which the canals are maintained, and is therefore responsive to the way that the system is managed. [ABSTRACT FROM AUTHOR]

A highly detailed digitized map depicts 22 benthic habitats in 3140.5 km² of the Florida Keys National Marine Sanctuary. Dominant are a seagrass/lime-mud zone (map area 27.5%) throughout Hawk Channel and seagrass/carbonate-sand (18.7%) and bare carbonate-sand (17.3%) zones on the outer shelf and in The Quicksands. A lime-mud/seagrass-covered muddy carbonate-sand zone (9.6%) abuts the keys. Hardbottom communities (13.2%) consist of bare Pleistocene coralline and oolitic limestone, coral rubble, and senile coral reefs. Smaller terrestrial (4.0%) and marine habitats, including those of live coral (patch reefs, 0.7%), account for the rest (13.7%) of the area. Derived from aerial photomosaics, the seabed dataset fits precisely when transposed onto a newly developed National Geophysical Data Center hydrographic-bathymetry map. Combined, the maps point to new information on unstudied seabed morphologies, among them an erosional nearshore rock ledge bordering the seaward side of the Florida Keys and thousands of patch-reef clusters aligned in mid-Hawk Channel. Preliminary indications are that the ledge may represent the seaward extent of the 125-ka Key Largo and Miami Limestone that form the keys, and the patch reefs colonized landward edges of two noncoralline, non-dune-ridge topographic troughs. The troughs, their substrate, and inner-shelf location along the seaward side of the Hawk Channel bedrock depression are the first of that type of nuclei to be recognized in the Florida reef record. Together, the map datasets establish the efficacy and accuracy of using aerial photographs to define in extraordinary detail the seabed features and habitats in a shallow-reef setting. [ABSTRACT FROM AUTHOR]

Airborne laser bathymetry (ALB) is a new laser bathymetric survey tool that has applicability in clear coastal (Case II) waters to depths of -70 m. The new sounding technique features rapid acquisition of large, high-quality data sets via variable swath widths that are independent of water depth. This advanced ALB system was deployed along the continental shelf of southeast Florida (Palm Beach, Broward, and Miami-Dade Countless, providing a contiguous data set for 160 km of coast from onshore to 6 km offshore. Image enhancement of the ALB digital data facilitates recognition of numerous seafloor features and bathymetric patterns. Bathymetric analysis of the 600-km² survey area on the continental shelf shows inherited lithologic features that are partly covered by surficial sediments. Primary parabathic (shore-parallel) provinces include: (1) nearshore rocky zones dominated by the Anastasia Formation, (2) coral-algal reef systems (Florida Reef Tract [FRT]), and (3) marine platforms (terraces). Sedimentary subprovinces include shoreface sands, interreefal sedimentary infills (coral rubble in basal sequences and near reef gaps), and finer-grained materials seaward of coral reefs. Tertiary topographic features include: (1) longshore bar and trough systems, shoals, sand sheets (flats), and diabathic (cross-shore) channels; (2) reef crests and ledges, forereef spur-and-groove topography, sediment ramps in large reef gaps, and incised paleo-river channels; and (3) drowned karst topography. Hierarchical organization (classification and mapping) of these bathymetric features is now possible for the first time because of the increased accuracy and density of ALB data. These data and related maps allow, for the first time, assessment of links between the influence of seabed morphology on wave transformation patterns and beach morphodynamics in southeast Florida. [ABSTRACT FROM AUTHOR]

Airborne laser bathymetric (ALB) systems rapidly acquire large, high-quality datasets via variable swath widths that are independent of water depth. Laser bathymetric survey tools have applicability in dear coastal (Case II) waters down to -70 meters depth. Deployed along the southeast Florida (Palm Beach, Broward. and Miami-Dade Counties) coast, an advanced ALB system provided a continuous dataset for 160 kilometers of coast from onshore to 6 kilometers offshore. Digital terrain models developed from this high-density bathymetric data permitted recognition of numerous seafloor features and bathymetric patterns from different image formats. Bathymetric analysis of the 600-km² survey area on the narrow continental shelf shows inherited lithulogic features that are partly covered by surficial sediments. Primary parabathic provinces include: (1) nearshore rocky zones dominated by the Anastasia Formation. (2) coral-algal reef systems (Florida Reef Tract [FRT]), and (3) marine terraces. Secondary sedimentary subprovinces include shoreface sands, inter-reefal sedimentary infills (coral rubble in basal sequences and near reef gaps), and finer-grained materials seaward of the FRT. Tertiary topographic features include: (1) longshore bar and trough systems, shoals, sand sheets, and diabathic channels; (2) reef crests and ledges, forereef spurs and grooves, sediment ramps in large reef gaps, and incised paleo-river channels; and (3) drowned karst topography. Hierarchical organization of these bathymetric features is now possible for the first time because of the increased accuracy and density of bathymetric data obtained by ALB systems. [ABSTRACT FROM AUTHOR]

High-resolution bathymetry surveys of Egmont Channel were conducted in 1999 and 2001 using a Kongsberg Simrad EM 3000 multibeam bathymetric system. These data were supplemented with other bathymetry data, seismic profiles, underwater scuba observations, and current velocity data, in order to investigate the geologic and hydrodynamic characteristics of Egmont Channel. Bounded to the north by a linear steep scarp ( ∼ 38°) and by a more gradual .slope (>10°) to the south Egmont Channel is an asymmetric tidal inlet and the main .shipping channel for Tampa Bay, Florida. The cross sectional area (17,964 m2) land the tidal prism (6X108 m3) for Egmont Channel were derived in this study. Currents measured at Egmont Deep and the Sunshine Skyway Bridge ( ∼ 11 km away I with Acoustic Doppler Current Profilers, have a high correlation (97%) indicating the current velocities at Sunshine Skyway Bridge can be used as a proxy for current velocities at Egmont Deep. Seismic profile data indicate that both tbe mouth of Tampa Bay and the bay proper contain many stratigraphically controlled depressions. Egmont Deep is located at one of these depressions. Bathymetry and seismic data indicate that the main ebb jet for Egmont Channel is deflected northward by a local stratigraphic high located at the north end of Egmont Key. The repeated high-resolution multibeam bathymetric surveys document sediment bedform migration. The bottom characteristics of the deep fluctuate due to the erosion and deposition of gravelwaves. Analysis of seismic data and SCUBA observations suggest that the most likely origin for Egmont Deep is a combination of erosion-resistant limestone strata interspersed with pockets of dissolution which is overlain by an irregular bed of mobile sediments. The strong tidal current scour maintains the depth of the feature and assures that any sediment that becomes incorporated in the deep is short-lived. [ABSTRACT FROM AUTHOR]

Quantitative data on beach changes caused by coastal storms is critical to the understanding of coastal morphodynamics and mitigation of coastal erosion hazards. Recent advances in airborne LIDAR technology allow large-scale mapping of beach erosion, dune scarping, and overwash deposition with incredible detail. By comparing 40 km of beaches along the central Florida Atlantic coast surveyed before and after Hurricane Floyd in 1999, we found that most beaches experienced erosion; about 18 to +1 m³/m of sediment per unit shoreline length were removed or deposited. Beach erosion is not spatially uniform, and variations in magnitude occur three dimensionally. The high-density LIDAR data provided accurate information about shore changes both at small and large scales. [ABSTRACT FROM AUTHOR]

The lagoons that border the east coast of the Florida peninsula provide an opportunity to study water chemistry and phytoplankton characteristics over a wide range of water residence and nutrient load conditions. This article includes the results of a 2-year study of eight study sites. The northern half of the sampling range included four sampling sites within the newly established Guana Tolomato Matanzas National Estuarine Research Reserve. The southern half of the sampling range consisted of four study sites distributed in ecologically distinct sub-basins of the Indian River Lagoon. The Guana Tolomato Matanzas National Estuarine Research Reserve and Indian River Lagoon include estuaries with water residence times ranging from days to months and watersheds with widely differing nutrient load characteristics. The results of this study revealed wide temporal and spatial variability of physical and chemical characteristics. Mean salinities for the study period ranged from 9.7 to 31.5% over the eight sites. Mean orthophosphate and total phosphorus concentrations ranged from 0.26 to 1.55 µM and 1.45 to 3.00 µM, respectively. Mean dissolved inorganic nitrogen and total nitrogen concentrations ranged from 3.14 to 9.77 µM and 26.43 to 71.14 µM, respectively. Individual phytoplankton standing crops, in terms of chlorophyll α concentrations, ranged from less than 1 µg L-1 to more than 60 µg L-1. Comparisons of the relationships between nutrient and phytoplankton standing crops at the eight study sites indicated that water residence times and nutrient loads provided important insights into the basis for observed temporal and spatial patterns of variability. Indices for water residence time and nutrient load were determined for each site. A combination of the character of watershed inputs and residence time was most useful in interpreting patterns of nutrient concentrations, whereas water residence time appeared to he the pre-eminent factor dictating phytoplankton standing crop potential among the eight study sites. [ABSTRACT FROM AUTHOR]

The need for a cautious interpretation of results from an analytic method for an analysis of the stability of tidal inlets is illustrated by comparing theory with data from St. Andrew Bay in Florida's panhandle. Historically this bay was connected to the Gulf of Mexico by East Pass at the eastern end of the bay. However, following the opening of St. Andrew Bay Entrance in 1934 at the western end to serve Panama City, the flow cross-section of this channel increased while East Pass contracted gradually and eventually closed in 1998. In December 2001 East Pass was reopened by dredging a small flow-relief channel. These events provided the opportunity to apply the stability analysis to the newly-formed two-inlet one-bay system. Interpretation of the results in terms of observed inlet stability versus prediction is shown to be contingent upon knowledge of the history of channel maintenance and the morphodynamics of the bay. The illustration underscores the need to apply the method in pre-project engineering investigations of the long-term impact of opening a second inlet in a bay. [ABSTRACT FROM AUTHOR]

Highlights the 50th Anniversary of the Coastal and Oceanographic Engineering academic program at the University of Florida. Mission and educational objectives; Accreditation; Research program; Inter-disciplinary modes; International activity.

Electromagnetic profiling and groundwater sampling on Sugarloaf Key and Little Torch Key in the Lower Keys of Florida show that these small, low-lying islands support only brackish-water lenses. On both islands, the lenses have central cores with lower salinities surrounded by areas of increasing salinity. The uppermost few meters of these central zones are uniform and slightly brackish (∼3 ppt) year-round on Sugarloaf Key. On Little Torch Key, which is smaller, there is a similar central, uniform brackish zone during the wet season, with salinity slightly higher than on Sugarloaf Key. These lenses are similar in form to many freshwater lenses, except that the central zone is slightly brackish rather than fresh. During the dry season Little Torch Key loses the central brackish zone, and salinities increase approximately linearly with depth. This dry-season pattern, in which the freshwater/saltwater mixing zone effectively extends throughout the lens, is similar to that documented on Enjebi Island on the Enewetak Atoll. Seasonal variations on Little Torch Key are less evident outside the central zone. The central lower-salinity core on Sugarloaf Key coincides with elevations > 0.8 m. Using vegetation as a proxy for elevation, the central zone corresponds to the highest elevations on Little Torch Key as well. Tidal efficiencies on Sugarloaf Key indicate the tidal signal propagates through the high-permeability, buried Key Largo Limestone, and then upward through the overlying lower permeability Miami Limestone that contain the lenses. Mixing driven by tidal pumping is likely responsible for the absence of true freshwater lenses on these islands. [ABSTRACT FROM AUTHOR]

The article offers information on the Bahia Honda State Park in Big Pine Key, Florida, discussing the limestone at the park, including the Key Largo Limestone and the Miami Oölite Limestone, and the plants such as yellow satinwood (Zanthoxylum flavum) and key thatch palm(Leucothrinax morrisii).

This article presents the Coastal Award of the American Society of Civil Engineers awarded to oceanographer Paul Komar at the Coastal Sediments Conference 2003 in St. Petersburg, Florida. The award is presented to an individual in recognition of having sustained achievement spanning two decades with contributions to both coastal science and engineering. Komar's achievements includes pioneering research in longshore sediment transport on beaches, the computer simulation of shoreline change, the initiation of sediment motion by waves and currents, and the formation of heavy-mineral placers on beaches. Komar is an emeritus professor of oceanography at Oregon State University.

A photograph of Saint (St.) Marks Wildlife Refuge and Lighthouse in Florida is presented.