Florida Beach Research Articles

Brevetoxin composition in water and marine aerosol along a Florida beach: Assessing potential human exposure to marine biotoxins

The toxic dinoflagellate, Karenia brevis, produces a suite of polyether neurotoxins (brevetoxins, PbTx) that cause massive fish kills and neurotoxic shellfish poisoning. A unique characteristic of K. brevis blooms is the associated airborne (aerosolized) toxin component causing respiratory irritation to humans and other mammals. This study was undertaken in collaboration with human respiratory effects studies to establish the type and amount of brevetoxins to which beach-goers were exposed during a coastal harmful algal bloom (HAB). Concentrations of K. brevis cells were monitored in water, and brevetoxin concentrations were monitored in water and air over 3-day periods during a non-exposure control study (no HAB) and an exposure study (HAB event) along the Gulf Coast of Sarasota, FL, USA. The aerosol particle size distribution was also determined to assess brevetoxin aerosol deposition in the human respiratory system. During the non-exposure study, very low to background K. brevis cell counts were observed on day 1 and at background levels (<1 × 10 3 cells/L) on days 2 and 3; brevetoxin concentrations were very low in water and non-detectable in air. In contrast, the exposure study samples exhibited moderate concentrations of K. brevis cells in surf water (1 × 10 5 to 1 × 10 6 cells/L) and brevetoxin concentrations (sum PbTx-1, -2, and -3) in water ranged from <1 to 14 μg/L. In air, brevetoxin concentrations were highest on day 1, diminishing on day 2, and below detection levels on day 3, reflecting a change in wind direction from onshore to offshore during this period. Quantitation of individual brevetoxins showed that PbTx-2 was the most abundant in water, while PbTx-3 was the most abundant in air. The brevetoxin antagonist, brevenal, also was detected in water and aerosol samples during the exposure study. Particle size distribution analyses indicated that most of the aerosolized brevetoxin would be deposited in the nasal, oral, and pharyngeal regions, consistent with reported upper airway symptoms of stinging eyes and nose and dry, choking cough from throat irritation. About 2–3% would be deposited farther down in the tracheobronchial and alveolar regions, as evidenced by symptoms of wheezing, airflow reduction and chest tightness.

Remarkable salt tolerance of naked amoebae from the Salton Sea and beyond

This study documents the salinity tolerance of naked amoebae from the Salton Sea, California, from intertidal sand in Dania Beach, Florida, and from freshwater. Amoebae were collected from hypersaline ponds around the perimeter of the Salton Sea, where salinities averaged 160‰, and directly from the shoreline waters of the Sea where salinities were generally between 44 and 48‰. Naked amoebae were also collected from the intertidal zone of a Florida beach, a habitat subject to salinity fluctuations in the range 6–85‰. From these sites, six clones of amoebae were isolated for subsequent salinity tolerance experiments (two marine beach isolates, two Salton Sea isolates, and two hypersaline pond isolates). A seventh clone, Acanthamoeba polyphaga, a common freshwater/soil amoeba, was obtained from the Culture Collection of Algae and Protozoa (CCAP), England, UK. The culture experiments compared the effects of gradually changing salinity versus no salinity acclimatization and used growth rate and culture yield as indices of effect. Generally, amoebae were tolerant over a wide range of salinity conditions and were not markedly influenced by pre‐conditioning to salinity throughout the experiments. For example, one Salton Sea species, Platyamoeba pseudovannellida n.sp. Hauer, Rogerson &amp; Anderson 2001, was able to survive and grow well without pre‐adaptation over the range 0–150‰. Overall, the freshwater amoeba Acanthamoeba grew between 0‰ and 12‰, the marine clones grew in the range of 0–110‰, and the Salton Sea clones reproduced between 0‰ and 150‰. The hypersaline clones were the most resilient and grew between 0‰ and 270‰. The results suggest that most amoebae are essentially unaffected in terms of growth and yield by moderate and severe salinity changes. This might partly explain the high abundances of amoebae found by the authors in salt‐challenged environments. Amoebae in the Salton Sea reached 237,120 cells/liter while those in intertidal sand ranged from 181 to 8,473 amoebae/cm3. The survival and activity of large populations of naked amoebae in sites subject to salinity fluctuations suggest that they should be considered in future studies to better understand their, as yet, undefined ecological role.

Failure of navy coating systems 1: chemical depth profiling of artificially and naturally weathered high-solids aliphatic poly(ester-urethane) military coating systems

A variety of weathering protocols are in use in industry and research laboratories to both replicate and accelerate the effects of weathering on coating systems. This work focuses on the use of two artificial and one natural weathering protocol (QUV, GM9540P, Florida beach exposure) in combination with spatially resolved transmission-mode Fourier transform infrared (FT-IR) spectroscopy for the purpose of chemically depth-profiling highly opaque high solids multi-layer poly(ester-urethane) coatings employed by the U.S. Department of Defense. Samples were prepared via subjection to 6/12-week GM9540P exposure, 7/13/25-week Florida beach exposure, or 6-/18-week QUV protocol. Thin (3 μm) cross-section samples were prepared via microtomy and depth-dependant trends in chemical evolutions were analyzed using transmission-mode micro-FT-IR. Scanning electron/energy-dispersive microscopy (SEM/EDS) was conducted on 10 μm cross-sections and spatial distribution/chemical makeup of inorganic constituents were analyzed. An apparent synergistic relationship between weathering protocols was found. It was theorized that a combination of chemistry and morphology of the inorganic fillers was primarily responsible for greater-than-expected photooxidative modification of the polymeric binder.

Development and Evaluation of Aggregate Destination Choice Models for Trip Distribution in Florida

Discrete choice modeling techniques have been used to model simultaneously the effects of land use and socioeconomic and demographic characteristics on travel behavior. To evaluate the performance of destination choice models with aggregate alternatives at the level of the travel analysis zone in allocating trips between zone pairs, this study developed three sets of home-based work models by using data collected from Broward, Palm Beach, and Volusia Counties in Florida. An objective for this study was to identify the benefit of destination choice models to urban areas of different sizes and characteristics. The spatial distribution patterns from the models were compared with those obtained from gravity models. The results from this study show that all urban areas benefited from destination choice models regardless of the urban size.

Landscape characteristics of Rhizophora mangle forests and propagule deposition in coastal environments of Florida (USA)

Field dispersal studies are seldom conducted at regional scales even though reliable information on mid-range dispersal distance is essential for models of colonization. The purpose of this study was to examine the potential distance of dispersal of Rhizophora mangle propagules by comparing deposition density with landscape characteristics of mangrove forests. Propagule density was estimated at various distances to mangrove sources (R. mangle) on beaches in southwestern Florida in both high-and low-energy environments, either facing open gulf waters vs. sheltered, respectively. Remote sensing and Geographic Information Systems were used to identify source forests and to determine their landscape characteristics (forest size and distance to deposition area) for the regression analyses. Our results indicated that increasing density of propagules stranded on beaches was related negatively to the distance of the deposition sites from the nearest stands of R. mangle and that deposition was greatly diminished 2 km or more from the source. Measures of fragmentation such as the area of the R. mangle forests were related to propagule deposition but only in low-energy environments. Our results suggest that geographic models involving the colonization of coastal mangrove systems should include dispersal dynamics at mid-range scales, i.e., for our purposes here, beyond the local scale of the forest and up to 5 km distant. Studies of mangrove propagule deposition at various spatial scales are key to understanding regeneration limitations in natural gaps and restoration areas. Therefore, our study of mid-range propagule dispersal has broad application to plant ecology, restoration, and modeling.

Do Harpacticoids (Copepoda) Use Water‐Borne Cues to Aid in Locating Food Parcels?

Abstract. Harpacticoid copepod food is patchily distributed and individuals must episodically move to new food patches. Key questions in harpacticoid feeding ecology include how individuals detect food patches and how rapidly they move toward patches. Based on literature reports, we hypothesized that harpacticoids locate food parcels by sensing a water‐borne cue. We tested this idea using individuals of Leptastacus coulli Huys, 1992 and Praeleptomesochra similis Lang, 1965 from a sandy beach in north Florida (29.948° N, 84.341° W). Individuals from both species selected seawater that had been exposed to food significantly more frequently than they selected control seawater. The rate of movement of these species was millimeters per second, which agreed with previous reports.

Severe infestation of cutaneous larva migrans

27-year-old otherwise healthy man presented to the mergency Department (ED) complaining of a rash on is buttock and right leg. The rash appeared after a amping trip on the beach in Florida 3 weeks prior. He tated the rash was intensely pruritic. The patient sought reatment in a local hospital and was prescribed cephaexin, steroids, and diphenhydramine, but despite his ompliance with the medications, the rash did not imrove. Physical examination revealed an erythematous rash overing the patient’s right and left buttocks and extendng down to include the entire right leg (Figure 1). A loser look revealed multiple excoriations and multiple erpiginous skin eruptions consistent with cutaneous arva migrans (Figure 2).

Origins of green turtle ( Chelonia mydas ) feeding aggregations around Barbados, West Indies

Although green turtles (Chelonia mydas Linnaeus) do not nest in Barbados, the easternmost island in the Caribbean archipelago, juveniles are regularly seen foraging in nearshore waters. To examine the stock composition of this foraging population, mitochondrial (mt) DNA control region sequences were analysed from 60 juvenile (31–70 cm curved carapace length) green turtles and compared with data published for key nesting populations in the Atlantic, as well as other feeding grounds (FGs) in the Caribbean. Eight distinct haplotypes were recognised among the 60 individual green turtles sampled around Barbados. Three of the haplotypes found have only previously been reported from western Caribbean nesting beaches, and two only from South Atlantic beaches. The nesting beach origin of one of the Barbados FG haplotypes is as yet unidentified. Stock mixture analysis based on Bayesian methods showed that the Barbados FG population is a genetically mixed stock consisting of approximately equal contributions from nesting beaches in Ascension Island (25.0%), Aves Island/Surinam (23.0%), Costa Rica (19.0%), and Florida (18.5%), with a lesser but significant contribution from Mexico (10.3%). Linear regression analysis indicated no significant effects of rookery population size or distance of the rookery from the FG on estimated contributions from the source rookeries to the Barbados FG. Our data suggest that the similar-sized green turtles sampled on the Barbados FG are a mixed stock of more diverse origins than any previously sampled feeding aggregations in the Caribbean region. The relatively large contribution from the Ascension Island rookery to the Barbados FG indicates that hatchlings from distant rookeries outside the Caribbean basin enter the North Atlantic gyre and become a significant part of the pool from which eastern Caribbean foraging populations are derived. These data support a life cycle model that incorporates a tendency of immatures to migrate from their initial foraging grounds at settlement towards suitable foraging grounds closer to their natal rookeries as they mature.

Visitor Preferences for Public Beach Amenities and Beach Restoration in South Florida

Coastal erosion threatens many sandy beaches and the ecological, economic, social and cultural amenities they provide. The problem is especially chronic in South Florida. A frequent solution for beach restoration involves sand replacement, or nourishment, but is temporary, expensive, and has usually been funded by governmental sources. However, as such agencies reduce their share and require more local funding, beach nourishment must rely on other funding sources, including beach recreationists. Our study characterized three South Florida beaches and probed visitor willingness-to-pay for beach nourishment. We found that even beaches within close proximity attract different user types. Users are amenable to higher fees if they lead to greater resource protection.

Recreational exposure to aerosolized brevetoxins during Florida red tide events

During two separate Karenia brevis red tide events, we measured the levels of brevetoxins in air and water samples, conducted personal interviews, and performed pulmonary function tests on people before and after they visited one of two Florida beaches. One hundred and twenty-nine people participated in the study, which we conducted during red tide events in Sarasota and Jacksonville, FL, USA. Exposure was categorized into three levels: low/no exposure, moderate exposure, and high exposure. Lower respiratory symptoms (e.g. wheezing) were reported by 8% of unexposed people, 11% of the moderately exposed people, and 28% of the highly exposed people. We performed nasal–pharyngeal swabs on people who experienced moderate or high exposure, and we found an inflammatory response in over 33% of these participants. We did not find any clinically significant changes in pulmonary function test results; however, the study population was small. In future epidemiologic studies, we plan to further investigate the human health impact of inhaled brevetoxins.

Spatiotemporal patterns of annual sea turtle nesting behaviors along an East Central Florida beach

The Florida coastline from Melbourne Beach to Wabasso Beach is one the most important nesting areas for loggerhead turtles (Caretta caretta) in the Western Hemisphere and for green turtles (Chelonia mydas) in the United States. In this study, we quantified the spatial patterns of numerous loggerhead (N≈400,000) and green turtle (N≈14,000) and less numerous (N≈100) leatherback (Dermochelys coriacea) beach ascents from 1989–1999 in terms of their autocorrelative properties along 40.5 km within this critical reproductive zone. Nesting and non-nesting emergence patterns of loggerhead and green turtles were non-random, favoring the southern half of the study area. Perhaps due to low numbers or differences in nesting behavior, leatherback nest distributions were not significantly different from random. Loggerhead and green turtle nest locations exhibited similar clinal patterns. They were positively autocorrelated at distances less than 10 km and negatively at distances greater than 30 km. These patterns were significantly correlated interannually.

Coating evaluation and validation of accelerated test conditions using an in-situ corrosion sensor

An in-situ corrosion sensor was used to obtain electrochemical impedance spectroscopy (EIS) measurements on coated panels under a variety of accelerated laboratory test conditions as well as ambient exposure at a Florida beach. Three studies are reported. The first compared the sensor (EIS) measurements taken in a salt fog chamber to those obtained using a clamp-on cell and the conventional remote electrode/immersion approach. For coatings with minimal edge defects, the two methods gave equivalent results. For coatings with edge defects, the sensor was able to detect the defects provided the surface was wet, as in the salt fog chamber. In contrast, the conventional approach was unable to detect defects unless they were within the confines of the clamp-on cell. In the second case, sensor measurements were used to compare coating degradation during salt fog, a cyclic corrosion test, humidity, and immersion to that occurring at a Florida beach. The cyclic corrosion test showed an excellent correlation with beach exposure while the salt fog and other test showed very little correlation, suggesting that the cyclic test is more valid for discriminating coating performance for seacoast exposure. The sensor also indicated that the test could be short-ened by up to 40% without significantly reducing the validity of the test. In the final example, a series of primers and appliques were evaluated using the cyclic corrosion test. The sensor EIS results allowed a discrimination between the materials sets even though there was little or no visual difference between the specimens.

Effects of Fire Ants (Hymenoptera: Formicidae) on Hatching Turtles and Prevalence of Fire Ants on Sea Turtle Nesting Beaches in Florida

Red imported fire ants (Solenopsis invicta Buren) have increasingly been observed in loggerhead (Caretta caretta L.) and green (Chelonia mydas L.) sea turtle nests in Florida, and in the nests of freshwater turtles. They may be attracted to the disturbance, mucous and moisture associated with turtle nesting and establish foraging tunnels into turtle nests shortly after egg-laying, thus increasing the vulnerability of hatchlings to fire ant predation. We conducted experiments on a freshwater turtle (Pseudemys nelsoni Carr) to determine the potential impacts of S. invicta on turtle hatchlings. Over 70% of hatchlings were killed by S. invicta during pipping or shortly after hatching. To determine the extent of S. invicta infestation of sea turtle nesting beaches, we sampled known nesting beaches throughout the state of Florida. Beach surveys indicated that S. invicta are present and often abundant on most beaches and dunes along the Florida coast.

AMSPDC: An overview of its history and evolving mission

AMSPDC: An overview of its history and evolving mission

A SEM Study of Epilithic and Endolithic Algae and Cyanophytes in Coquina Beach Rock of North Central Florida

Abstract The eastern coast of north central Florida is home to a habitat unique in the southeastern United States. Some areas of the north to north-central Florida beaches consist of outcroppings of coquina, a beach rock formed by shell fragments and sand held together by a calcareous cement. The major constituents of coquina are shell fragments of the surf clam Donax variabilis, while fragments of Area sp. and Dinocardium sp. are also generally present. These same shell fragments are also found loose comprising most of the beach “sand” in this area. The coquina serves as a substrate for a variety of attatched seaweeds and fouling organisms. Microalgae and cyanophytes of interest to this study can be classified as either epilithic or endolithic. Epilithic microorganisms inhabit the surface, using the rock primarily as a site of attatchment. The endolithic microorganisms are those algae and cyanophytes that actively bore into the coquina rock's shell fragments.

Comparison of Elements in Bottlenose Dolphins Stranded on the Beaches of Texas and Florida in the Gulf of Mexico over a One-Year Period

We analyzed tissue samples from bottlenose dolphins (Tursiops truncatus) that had stranded on beaches in Texas and Florida over a 1-year period starting in September 1991. The concentrations of 10 elements plus methyl mercury (MeHg) were determined in brain, kidney, and liver, and we examined these results for differences based upon age, site, sex, and tissue type. A strong inverse relationship between total mercury (Hg) and the percentage that was MeHg was found in liver, kidney, and brain tissue, presumably due to demethylation of MeHg. A threshold concentration was found for total Hg in brain tissue, indicating that most Hg was present as MeHg up to about 8 years of age. Increases in total Hg after this age were accompanied by an increase in the ratio of total Hg to MeHg, indicating demethylation. Strong relationships were found between total Hg in liver and age and between total Hg and selenium in liver, which have been observed before in many fish- and squid-eating marine mammals. The only difference based on sex of the animals was observed for MeHg, which was higher in females and contrary to the pattern often observed for organic contaminants. Several elements (copper, Hg, lead, zinc) exhibited intersite differences, which were not consistent. Bottlenose dolphin from Florida exhibited the highest levels of MeHg and total Hg, while animals from Texas exhibited the highest levels of lead, copper, and zinc. The essential elements copper and zinc were expected to be the same for the Texas and Florida animals; however, observed differences may indicate population differences in basic physiological levels, dietary intake, or health status.

An analysis of the sexual, alcohol and drug related behavioural patterns of students on spring break

Little information is available regarding the consensual sexual activity of young adults on holiday. Both academic and popular press coverage of sex and travel has tended to focus on commercial sex. This study examines the sexual activity, alcohol and drug use of US college students during ‘Spring Break’ at a popular Florida beach destination. The results suggest that students engaged in more sexual activity and had more new sexual partners during their holiday than in the previous month. Students were also found to engage in heavy alcohol consumption and some drug abuse, placing them at higher risk for contracting sexually transmitted diseases (STDs). Those motivated to visit this destination by its ‘party reputation’ consumed significantly more alcohol, compared to those with other motivations. The results suggest implications for health education, tourism marketing, and public policy decisions.

Winter mortality of common loons in Florida coastal waters.

Diagnostic findings are presented for 434 common loons (Gavia immer) found sick or dead on Florida beaches from 1970 through 1994, primarily during the months of December to April. The most commonly recognized problem was an emaciation syndrome (66%), followed by oiling (18%), aspergillosis (7%), trauma (5%) and miscellaneous disease entities (1%). The cause-of-death for 3% of the birds was not determined. Many of the carcasses examined (n = 173) were obtained during an epizootic which occurred from January to March of 1983 in which more than 13,000 loons were estimated to have died. An emaciation syndrome, characterized by severe atrophy of pectoral muscles, loss of body fat and hemorrhagic enteritis, was the primary finding in this epizootic. It was postulated to have a complex etiologic basis involving synergistic effects and energy costs of migration, molting and replacement of flight feathers, food resource changes, salt-loading, intestinal parasitism, environmental contaminants, and inclement weather.

Thermal effects of condominiums on a turtle beach in Florida

Beach temperatures at the depth of nests were studied at the loggerhead turtle Caretta caretta rookery at Boca Raton, Florida. The sand at 30 and 60 cm depth in areas shaded by condominiums averaged about 1°C cooler than that in adjacent areas unshaded by buildings. With particularly large condominiums, differences were as large as 2°C. Longer incubation durations of nests laid close to buildings were consistent with such sites being cooler. In the heat of midsummer, when temperatures on this beach were almost always well above the pivotal level, the shade from condominiums probably did not alter the sex ratio of the hatchlings. However, at the cooler start of the season, shade reduced temperatures to below the pivotal level, presumably increasing the number of males produced at this time.

Sperm competition in horseshoe crabs ( Limulus polyphemus )

Male horseshoe crabs have two mating tactics. Some males come ashore attached to a female (clasping the posterior margin of the females' carapace with their modified pedipalps) and nest with her on the intertidal portion of the beach during the high tide. Other males come ashore unattached and crowd around nesting couples. Fertilization is external and unattached males that are in contact with a pair, i.e. ‘satellite’ males, release sperm, so the assumption has been that they are fertilizing eggs. We conducted a paternity analysis to determine the proportion of eggs fertilized by attached and satellite males. Pairs with one satellite were observed during nesting on beaches in Florida and Delaware and their eggs were collected and reared to the late trilobite or first instar horseshoe crab stage. DNA was extracted from these offspring and from each adult (female, attached and satellite male) for use in paternity analysis. A Limulus-specific hypervariable microsatellite locus was identified and primers were constructed to amplify this locus via the polymerase chain reaction (PCR). Genotypes of putative parents and offspring were determined by resolving length variants of these PCR products on acrylamide gels. This allowed us to determine parentage of the offspring. We demonstrate that satellite males fertilized 40% of the eggs on average, attached males fertilized 51% and 4% of the eggs that were laid by the female were fathered neither by the attached male nor by the satellite (and 5% could not be determined unambiguously). There is high variability in the success of satellite males, ranging from 0 to 88%. Part of this variability can be explained by the position of the satellite relative to the attached male. We discuss the mechanics of fertilization and the possible advantages for multiple mating in this species.