Ponce De Leon Inlet Research Articles

Florida Inlets and Intertidal Biofouling Communities

AbstractThis study reports on the identity and coverage of rocky intertidal species in the major inlets of Florida’s Atlantic coast. From north to south, these inlets are Fort George, St. Augustine, Ponce De Leon, Port Canaveral, Sebastian, Fort Pierce, Jupiter, Lake Worth, Boca Raton, Port Everglades, Baker’s Haulover, and Port of Miami. Dominant coverage in the southerly inlets included star corals (Siderastrea radians,62% Port of Miami), ribbed barnacles (Tetraclita stalactifera, 18% Port Everglades), and zoanthid corals (Palythoasp., 40% Baker’s Haulover). In the north, the community shifted and species absent in the south became common (e.g., eastern oystersCrassostrea virginica, 9% Fort George, 15% St. Augustine; the macroalgaEnteromorpha lactuca, 10% Fort George, 17% Sebastian Inlet). The invasive bryozoanBugula neritinawas always present north of the Port of Miami and was a major community component north of Port Everglades (e.g., 27% Fort Pierce Inlet and 22% Ponce de Leon Inlet). Correlations between intertidal populations and environmental indicators included the oysterC. virginicawith various sea surface temperature (SST) parameters (e.g., inverse correlations with max SST,R2= 0.81,p= .038). Likewise, the coralline algaPneophyllum fragilewas correlated with various SST parameters (e.g., min SST,R2= 0.51,p= .020). Bare rock andB. neritinaboth showed inverse correlations with the human population of inlet drainage basins (R2= 0.28,p= .040 andR2= 0.33,p= .026, respectively), the latter relationship an unexpected pattern for a notorious invader. These data show latitudinal patterns and provide baselines for future comparisons in the wake of projected climate change.

Tracking the distribution of non-native marine invertebrates (Mytella charruana, Perna viridis and Megabalanus coccopoma) along the south-eastern USA

Our study tracked three non-native, marine, sessile, invertebrate species which have recently colonized the south-eastern United States Atlantic coastlines and estuaries: Mytella charruana, the charru mussel; Perna viridis, the Asian green mussel; and Megabalanus coccopoma, the titan acorn barnacle. Along the eastern Floridian coast, Mytella charruana was discovered in the Indian River Lagoon, Florida (FL) in 2004. Perna viridis was found in Ponce de Leon Inlet, FL in 2002, after being introduced to Tampa Bay, FL in 1989. Megabalanus coccopoma was documented in St Augustine, FL and Brunswick, Georgia in 2006. From 2006 through to 2011, a biannual survey of the south-eastern Atlantic coastlines and estuaries was conducted from Jupiter, Florida to Charleston, South Carolina (894 km) to document the distribution and range expansion of M. charruana, P. viridis and M. coccopoma. Field surveys were conducted in June and December each year at 82 sites (e.g. docks, boat ramps, jetties and mangrove roots). The ranges of the three invertebrates have expanded and retracted along the Atlantic coast since the survey began. Mytella charruana had spread as far north as Savannah, Georgia in 2007, but the species was absent from northern Georgia in 2010 and 2011. Perna viridis and M. coccopoma were present in Georgia in 2007, but were absent in the 2010 and 2011 surveys. These range fluctuations may be explained by extreme cold temperatures, which occurred during the 2009/2010 and 2010/2011 winters. The patterns observed with these three sessile invertebrates provide information regarding how non-native species disperse and establish in new locations.

Water wave simulation in curvilinear coordinates using a time-dependent mild slope equation

The purpose of this article is to model the detailed progress of wave propagation in curvilinear coordinates with an effective time-dependent mild slope equation. This was achieved in the following approach, firstly deriving the numerical model of the equation, i.e., Copeland's hyperbolic mild-slope equation, in orthogonal curvilinear coordinates based on principal of coordinate transformation, and then finding the numerical solution of the transformed model by use of the Alternative Directions Implicit (ADI) method with a space-staggered grid. To test the curvilinear model, two cases of a channel with varying cross section and a semi-circular channel were studied with corresponding analytical solutions. The model was further investigated through a numerical simulation in Ponce de Leon Inlet, USA. Good agreement is reached and therefore, the use of the present model is valid to calculate the progress of wave propagation in areas with curved shorelines, nearshore breakwaters and other complicated geometries.

Variation of overtides by wave enhanced bottom drag in a North Florida tidal inlet

Month-long observations of waves and tidal currents at Ponce de Leon Inlet, North Florida are used to investigate the importance of wave-induced bottom drag as a mechanism for overtide generation in estuaries. While bottom drag can in theory lead to overtide generation, in practice, resolving unambiguously this effect is difficult as it tends to be overshadowed by the stronger effect of diurnal–semidiurnal tidal variance. Bottom boundary layer numerical simulations based on observational data suggest that waves can cause the bottom drag experienced by currents to increase by a factor of 1.7, compared with relatively calm conditions. Despite the relatively short duration and limited scope of the experiment, the analysis suggests that overtide modulations (East–West velocity components of the 5th and 6th diurnal constituents) are correlated with wave-enhanced drag trends. Therefore, wave-enhanced bottom drags may be enhancing generation of overtides. Further work is necessary to understand the scope and the strength of this mechanism, in relation to the characteristics (e.g., flow direction) of individual overtides.

Transverse structure of subtidal flow in a weakly stratified subtropical tidal inlet

The transverse structure of exchange flows and lateral flows as well as their relationship to the subtidal variability are investigated in a subtropical inlet, Ponce de Leon Inlet, Florida. Two surveys were executed during different phases of the tidal month to determine the spatial structure of subtidal exchange flows. Data from fixed moorings were used to depict the temporal variability of the spatial structure established in the surveys. The data suggested a tidally rectified pattern of net outflow in the channel and inflow over shoals with a negligible influence of streamwise baroclinic pressure gradients on the dynamics and slight modifications due to the wind. Onshore winds strengthened net inflows but weakened net outflows, rarely reversing them, while offshore winds increased net outflows and weakened net inflows. Curvature effects were found to be important in modifying secondary circulations. Slight modifications to the secondary flows were also caused by stream-normal baroclinicity during one survey. Most important, the intensity of the exchange flows was modulated by tides, with the largest exchange flows developing in response to the strongest tidal rectification of spring tides.

Circulation and Flushing in the Lagoonal System of the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR), Florida

Circulation and flushing inside the lagoon system of Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR or GTM) have been studied using a three-dimensional numerical circulation model CH3D. The lagoon system includes two tidal inlets (St. Augustine Inlet and Matanzas Inlet). To ensure accuracy in model results, we extend the model domain to include a large portion of the coastal water and the Ponce de Leon Inlet in the south. Water levels on the open boundaries are provided by the East Coast (2001) ADCIRC Tidal Database. Model simulations of barotropic and baroclinic circulation from April 1 to May 31, 2004, produced reasonable water levels at numerous stations inside the GTM. Simulated salinity results are not as good because of the lack of freshwater inflow data inside the GTM and salinity data offshore. Using the simulated flow fields, we solve the three-dimensional transport equations for conservative species, and determine the flushing characteristics inside the GTM in terms of the 50% renewal time of the conservative species within each of eight segments, which are selected by considering the geographical features and proximity to tidal inlets and rivers. The flushing results indicate that tide is the most dominant flushing mechanism, while river and salinity are important flushing mechanisms for segments that are far from the tidal inlets. The normalized flushing times, defined as the 50% renewal time divided by the volume of the segment, are calculated for the eight segments and compared with each other. Comparing the “normalized” flushing time at all segments, a relative flushing ranking (RFR) is generated that ranks the “normalized” flushing time from the shortest to the longest as follows: segment 2 (includes St. Sebastian), segment 8 (near Ponce Inlet), segment 3 (includes Fort Matanzas), segment 7 (near Ponce Inlet), segment 1 (includes Pine Island), segment 4 (includes Pellicer Creek), segment 6 (includes High Bridge Road), and segment 5 (includes Bings Landing). This quantitative ranking of flushing characteristics inside the GTM is made possible because of the use of a three-dimensional numerical circulation and transport model that incorporates the effect of hydrodynamics on flushing. These results provide much more quantitative information than the simple empirical residence time indices (1–4) developed for the GTM in a previous study. CH3D was also applied to simulate the circulation during January 25 to February 3, 2006. Simulated currents inside the St. Augustine Inlet on February 2, 2006, compare favorably with the currents measured by Acoustic Doppler Current Profiler (ADCP). Model simulated flow rates through St. Augustine and Matanzas inlets reproduced measured data on July 1 and June 16, 2004, respectively. Model-simulated currents and water levels improved when the flooding-and-drying version of the model was used. The three-dimensional modeling approach can be used to provide sguidance on resource management and the development of sampling strategies for several ongoing and prospective biogeochemical studies in the GTM.

Wave Simulations in Ponce de Leon Inlet Using Boussinesq Model

An improved curvilinear grid model based on fully nonlinear Boussinesq equations is used to simulate wave propagation in Ponce de Leon Inlet, Fla. We employ the nearshore bathymetry of Ponce de Leon Inlet and generate a stretched curvilinear grid that can resolve shortwaves in the nearshore region and fit the complex geometry. Simulations of 18 cases with monochromatic input waves and Texel-Marsden-Arsloe spectral waves are carried out on the same scale as in the 1:100 scale physical model conducted at the U.S. Army Engineer Research and Development Center. Wave height comparisons, time series comparisons of surface elevation for monochromatic wave cases, and comparisons of power spectrum for spectral wave cases are made between numerical results and laboratory measure- ments. Comparison is also made between the probability distribution of surface elevation and skewness and asymmetry measures for both the measured data and the Boussinesq model results. It is shown that for the computations of nonlinear wave transformation over irregular bathymetry, the Boussinesq model is able to predict nonlinear wave features and is thus a more accurate model than some conventional models in shallow water.

Numerical Modeling of Waves at Ponce de Leon Inlet, Florida

Coastal inlets pose challenges of complex bathymetry, wave-current interaction, and influences of natural and artificial barriers for prediction of wave transformation with numerical wave models. The steady-state spectral WAVE model is described and evaluated with directional wave data measured during two storms (5.4 m and 2.4 m peak wave height) at Ponce de Leon Inlet, on the Atlantic coast of Florida. Model simulations of the two storms agreed well with measurements (within measurement uncertainty) except when incident waves were strongly nonlinear. Wave-current interaction was found to be a small influence compared to refraction by changing water depth.

Patterns in Species Composition of Fish and Selected Invertebrate Assemblages in Estuarine Subregions near Ponce de Leon Inlet, Florida

The Florida Fish and Wildlife Conservation Commission's Fisheries-Independent Monitoring program monitored the species composition and relative abundance of fishes and selected invertebrates in the estuarine waters near Ponce de Leon Inlet, Florida, from January 1993 through to December 1996. Sampling sites were located in three distinct physiographic and biotic estuarine subregions: Mosquito Lagoon (ML; 11 stations), Ponce de Leon Inlet (PI; 8 stations), and Tomoka Basin/River (TR; 8 stations). This series of subregions associated with Ponce de Leon Inlet is a species-rich estuarine system that is numerically dominated by a few taxa. A total of 1080477 animals representing 160 species and 56 families were recorded.Anchoa spp. (29·9%) and Menidia spp. (12·6%) were the numerically dominant taxa. Sciaenidae and Gobiidae were the most speciose families, with 12 species each (14·0% and 1·7% of the total animals collected, respectively), followed by the bothids 10 species (0·6% of total animals). Detrended correspondence analysis showed that the subregions could be discriminated by their respective species composition and relative abundance. Spatial differences in species composition were principally attributed to differences in the magnitude of seasonal recruitment events and to habitat characteristics associated with the presence of seagrass, inlet dynamics, or the influence of freshwater discharge. The presence of freshwater taxa (centrarchids) and the seasonal recruitment of juvenile Penaeidae,Micropogonias undulatus , Stellifer lanceolatus and Leiostomus xanthurus, characterize the TR area, whereas the presence of species associated with higher salinities (Opisthonema oglinum and Harengula jaguana) characterize PI and with seagrass (Lucania parva and Lagodon rhomboides) characterize ML.

PERFORMANCE OF A JETTY-WEIR INLET IMPROVEMENT PLAN

Comprehensive monitoring has been carried out since 1970 to determine the performance and effects of a navigation and inlet stabilization project at Ponce de Leon Inlet, Florida. The improvement plan at the tidal inlet included construction of two jetties, a weir sand by-pass system, and dredging of a navigable channel (Figure 1). An evaluation was made of the general current patterns, the relative refracted wave energy distribution, and the volumetric beach and hydrographic fluctuations associated with the inlet. An analysis of this data was used to interpret the dramatic and unexpected changes which have resulted along the adjacent coastline and within the inlet after the completion of the inlet improvements.

By-Passing and Back-Passing with Reference to Florida

By-passing by natural action is examined with special reference to Florida Inlets. The present status of by-passing plant operations in Florida is reviewed, including the 40-yr-old installation at the South Lake Worth Inlet and the 10-yr-old installation at the Palm Beach Inlet. The existing by-passing arrangement at the Hillsboro Inlet is based on transfer from deposit basin inside the weir section in the updrift side jetty; the planned transfer arrangement at the Ponce de Leon Inlet is based on the same principle. Inasmuch as it is evident that by-passing plants, partly because of the tidal flow that discharges material in the ocean and in the bay and partly as a result of the rise of sea level, will not be able to solve more than a certain part of a beach erosion problem, replenishment by sand from other sources is indispensable. The most logical source is offshore deposits. Material may be brought to shore by back-passing, using an offshore scraper for maintenance or a special hydraulic dredge for major improvements. If the borrow area is located close to shore, the question arises of whether the borrow pit will fill up again with material from further offshore, material from the sides, or material dragged out by waves from the beach. Tests performed on Jupiter Island using an offshore scraper are described briefly.