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Pleistocene carbonates of south Florida and islands of the Florida Keys are currently divided into five marine sequences designated, from oldest to youngest, the Q1-Q5 units. The units include a mosaic of freshwater and shallow marine deposits that accumulated on the Florida platform during high sea-level stands. The units are separated by regionalscale subaerial-exposure surfaces that formed during glacioeustatic lowstands. Analyses of cores recovered at Grossman Ridge Rock Reef and Joe Ree Rock Reef in the Florida Everglades reveal additional subaerial-exposure surfaces that are used to delineate subdivisions within units Q1 (Q1a-Q1b), Q2 (Q2a-Q2d), and Q4 (Q4a-Q4b). Units Q1-Q5 preserve evidence of at least 10 separate sea-level highstands, rather than 5 as indicated by previous studies. Compilation of available uranium-series dates on corals recovered from the Florida Keys indicates that the Q4 unit accreted during sea-level maxima associated with marine oxygen-isotope Stage 9 (Q4a) and isotope Stage 7 (Q4b). The Q5 unit formed during isotope Stage 5. No reliable dates are available for units Q1-Q3. We infer that unit Q3 was formed during the extended sea-level highstand of isotope Stage 11 and that units Q2 and Q1 predate isotope Stage 11. [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]

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]

A regional study of the Holocene sequence onlapping the west-central Florida Platform was undertaken to merge our understanding of the barrier-island system with that of the depositional history of the adjacent inner continental shelf. Key objectives were to better understand the sedimentary processes, sediment accumulation patterns, and the history of coastal evolution during the post-glacial sea-level rise. In the subsurface, deformed limestone bedrock is attributed to mid-Cenozoic karstic processes. This stratigraphic interval is truncated by an erosional surface, commonly exposed, that regionally forms the base of the Holocene section. The Holocene section is thin and discontinuous and, north or south of the Tampa Bay area, is dominated by low-relief sand-ridge morphologies. Depositional geometries tend to be more sheet-like nearshore, and mounded or ridge-like offshore. Sand ridges exhibit 0.5–4 m of relief, with ridge widths on the order of 1 km and ridge spacing of a few kilometers. The central portion of the study area is dominated nearshore by a contiguous sand sheet associated with the Tampa Bay ebb-tidal delta. Sedimentary facies in this system consist mostly of redistributed siliciclastics, local carbonate production, and residual sediments derived from erosion of older strata. Hardground exposures are common throughout the study area. Regional trends in Holocene sediment thickness patterns are strongly correlated to antecedent topographic control. Both the present barrier-island system and thicker sediment accumulations offshore correlate with steeper slope gradients of the basal Holocene transgressive surface. Proposed models for coastal evolution during the Holocene transgression suggest a spatial and temporal combination of back-stepping barrier-island systems combined with open-marine, low-energy coastal environments. The present distribution of sand resources reflects the reworking of these earlier deposits by the late Holocene inner-shelf hydraulic regime. [Copyright &y& Elsevier]

Analyzes the impact of the `Storm of the Century', an extratropical storm, which passed along Florida's west-central coastline on March 12-13, 1993 on the Waccasassa Bay system. Details of the Bay area; Analysis of the storm deposition in the area in the absence of any shoreline erosion along the salt-marsh coast; Details of the sampling and study; Hypothesis regarding the evolution of marshes under microtidal, low-wave-energy climate.

This article discusses some aspects of mortality in Florida between 1921-1930. It is well known that certain diseases are much more prevalent in the tropics and semi-tropics than elsewhere, and it has been alleged that as a result of these diseases, general mortality rates are much higher than in temperate zones. The author feels that this allegation is not true. This study is done by making comparisons between Florida's mortality rates and the Wisconsin's mortality rates. Wisconsin was chosen because of its many similarities to Florida. Of the seventeen diseases and causes of death analyzed, nine are against Florida when compared with Wisconsin. These diseases and causes of death are typhoid, malaria, puerperal causes, suicide, homicide, auto accidents, pellagra, old age, and septicemia. It can reasonably be said that puerperal causes, pellagra, and auto accidents are not because of the climate. It is seen that automobile accidents have been much greater in Florida because of the large number of non-resident motorists. Likewise it is seen that pellagra is caused by an unbalanced diet. Florida's much higher rates from puerperal causes are no doubt largely due to poverty and ignorance. As contrasted with the causes of death against Florida, it is seen that six are decidedly in favor of Florida. These are measles, whooping cough, tuberculosis, cancer, heart diseases, and pneumonia. For diphtheria and influenza, Florida's rates are about the same as Wisconsin's area. To conclude, if auto accidents, pellagra, and puerperal causes, which clearly are not attributable to the climate, were excluded, there is only one cause which takes a much greater toll of death in Florida.

Private wells throughout central Florida have arsenic levels above the maximum contaminant level (MCL) of 10 µg/L. We conducted a biomonitoring project of residents with wells above the MCL (higher risk) and below 8 µg/L (lower risk) to determine the relative importance of dietary and water sources of arsenic. Urinary arsenic did not differ by risk status, though higher-risk residents were more likely to use bottled or filtered well water as their primary source for drinking, cooking, and brushing teeth. Higher income, home ownership, and more servings of fish, seafood, white rice, and wine were associated with higher urinary arsenic levels. Similar relationships were seen when excluding individuals who consumed fish or seafood within 3 days of sampling. Provision of filters and bottled water to higher-risk households provided protection from arsenic exposure through well water. Diet and lifestyle factors, however, contributed to higher urinary arsenic levels among participants, regardless of household risk status. [ABSTRACT FROM AUTHOR]

Sediment vibracores and surface samples were collected from the mixed carbonate/siliciclastic inner shelf of west–central Florida in an effort to determine the three-dimensional facies architecture and Holocene geologic development of the coastal barrier-island and adjacent shallow marine environments. The unconsolidated sediment veneer is thin (generally <3 m), with a patchy distribution. Nine facies are identified representing Miocene platform deposits (limestone gravel and blue–green clay facies), Pleistocene restricted marine deposits (lime mud facies), and Holocene back-barrier (organic muddy sand, olive-gray mud, and muddy sand facies) and open marine (well-sorted quartz sand, shelly sand, and black sand facies) deposits. Holocene back-barrier facies are separated from overlying open marine facies by a ravinement surface formed during the late Holocene rise in sea level. Facies associations are naturally divided into four discrete types. The pattern of distribution and ages of facies suggest that barrier islands developed approximately 8200 yr BP and in excess of 20 km seaward of the present coastline in the north, and more recently and nearer to their present position in the south. No barrier-island development prior to approximately 8200 yr BP is indicated. Initiation of barrier-island development is most likely due to a slowing in the Holocene sea-level rise ca. 8000 yr BP, coupled with the intersection of the coast with quartz sand deposits formed during Pleistocene sea-level highstands. This study is an example of a mixed carbonate/siliciclastic shallow marine depositional system that is tightly constrained in both time and sea-level position. It provides a useful analog for the study of other, similar depositional systems in both the modern and ancient rock record. [Copyright &y& Elsevier]

The shelf-valley system underlying Tampa Bay, Florida’s largest estuary, is situated in the middle of the Neogene carbonate Florida Platform. Compared to well-studied fluvially incised coastal plain valley systems, this shelf-valley system is unique in its karstic origin and its alternating carbonate-siliciclastic infill. A complex record of sea-level changes, paleo-fluvial variability and marine processes have controlled the timing and mechanisms of this ‘compound’ shelf-valley infill. A dense grid of high-resolution, single-channel seismic data were collected at the mouth of Tampa Bay, in an attempt to define this stratigraphy, determine the controls on deposition, and define the underlying structure of this shelf-valley system. The seismic data were correlated with nearby wells and boreholes for lithologic and age control. Sequence stratigraphic methods were incorporated in order to develop an integrated chronostratigraphy for the depositional infilling of the shelf-valley system. Five seismic sequences were identified. Sequence boundaries generally show erosional truncation and karstification, with downlap of overlying sequences. Structure contour and isopach maps indicate that the Tampa Bay shelf-valley system has remained in essentially the same location since its formation in the early Miocene, although the provenance of sedimentary infill has changed. This change is due to increasing amounts of siliciclastic material during the Neogene. Seismic facies interpretations indicate lower-energy, northward prograding deposition dominated by predominantly carbonate sediments within the lowest Sequence A. Higher energy, siliciclastic fluvio-deltaic deposition within sequences B and C originates to the east and northeast of the shelf-valley system related to a Pliocene pulse of sedimentation onto the Florida Platform. Finally, marine processes (longshore transport, ebb-tidal delta formation) dominate the upper two sequences (D and E), reworking these siliciclastic sediments into a spatially mixed carbonate-siliciclastic depositional setting. [Copyright &y& Elsevier]