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Research about Tampa Bay

Source-linked reports with geographic coverage including Tampa Bay.

At least 19 recordsLinked to original sources
USGS2024

Assessment of the interconnection between Tampa Bay and the Floridan aquifer system: Historical groundwater data compilation and analysis, 1976–2022

The U.S. Geological Survey used existing data collected after the last major navigational channel modification in the mid-1980s to investigate groundwater levels and chloride concentrations in wells in the Floridan aquifer system and other aquifers beneath and near Tampa Bay. Tampa Bay is located on the west-central coast of Florida and provides access for commercial shipping. In 2021, the U.S. Army Corps of Engineers began to investigate alternatives to improve the efficiency of the deep-draft navigation channels within Tampa Bay, reduce costs, improve safety, and analyze the implications of modifying navigational channels. The Floridan aquifer system underlies Tampa Bay and is the primary source of public water supply in the region. Modifications to the channels have the potential to expose the Floridan aquifer system to the saltwater in Tampa Bay, with the potential to increase salinity in wells in the region. Other factors affecting the groundwater levels and the location of the freshwater/saltwater interface were also examined, including changes in sea level, groundwater extraction, and variations in climate. Groundwater levels and well-construction reports were used to identify whether different aquifer units are well-connected. Twelve wells had available data before and after the last major channel modifications, which took place in the 1980s, with six datasets of chloride concentration available in areas along the northern and eastern coastline of Tampa Bay, which is nearest to historical dredging activities. Of these six, Kendall’s τ and p -values indicated increasing trends in chloride concentration for three datasets (TR 11-2, TR 10-2, 51), no trend in chloride concentration for two datasets (TR 9-3, 50), and a decreasing trend in chloride concentration for one dataset (TR 9-1). The upward trends in chloride concentration observed for TR 10-2 and 51 are likely the result of changes in local groundwater withdrawals. Well TR 11-2 had a gradual increasing trend in chloride concentration, fresh groundwater throughout the period of record, and a 3- to 4-foot increase in hydraulic head during the period of record, possibly caused by the construction and control of the Tampa Bypass Canal, resulting in changes to the regional potentiometric surface.

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USGS2022

Assessing per- and polyfluoroalkyl substances (PFAS) in sediments and fishes in a large, urbanized estuary and the potential human health implications

The primary source of chronic exposures to per- and polyfluoroalkyl substances (PFASs) in humans is through the ingestion of contaminated foods and drinking water, with fish and other seafood being a major contributor. Nevertheless, there is scant literature on the dietary exposure to PFASs for the general United States (U.S.) population. The Tampa Bay (Florida, USA) region has the highest population density in the State and communities and their attendant support services are arrayed in an urban to semi-rural continuum from the head of the Bay to the ocean mouth. Tampa Bay supports productive recreational and commercial fisheries, providing a diverse community of species. A variety of potential PFAS sources surround Tampa Bay including airports, industry, wastewater treatment plants, fire-fighting training areas and military installations. The objective of this study is to quantify PFASs in sediment and fishes collected from Tampa Bay to further estimate human health risks from dietary exposures. Sediment ( n = 17) and fish (24 species, n = 140) were collected throughout Tampa Bay in 2020 and 2021 and analyzed for 25 PFAS compounds. Concentrations of PFASs in sediments and edible tissues of fish ranged from 36.8 to 2,990 ng kg -1 (dry weight) and 307 to 33,600 ng kg -1 (wet weight), respectively. Generally, levels were highest in Old Tampa Bay and decreased south towards the Gulf of Mexico. Profiles in both matrices were generally dominated by perfluorooctane sulfonic acid (PFOS) with variations by location. Estimated human health risks from the consumption of contaminated fish collected in Tampa Bay exceeded concentration thresholds for minimum risk levels (MRLs) and tolerable weekly intake (TWIs) values for adults and youths. Additionally, concentrations of PFOS in edible fish tissues of several recreationally important species collected in Tampa Bay exceeded consumption guideline levels established by several governmental agencies. In the current context, the elevated levels of PFAS in Tampa Bay and the exceedances of available thresholds for potential human health risks are a cause for concern and justify a more intensive examination especially for more heavily utilized species, particularly those used in subsistence-level fishing, which, as elsewhere may be significantly under documented.

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USGS2020

Rapid peat development beneath created, maturing mangrove forests: Ecosystem changes across a 25-year chronosequence

Mangrove forests are among the world’s most productive and carbon‐rich ecosystems. Despite growing understanding of factors controlling mangrove forest soil carbon stocks, there is a need to advance understanding of the speed of peat development beneath maturing mangrove forests— especially in created and restored mangrove forests that are intended to compensate for ecosystem functions lost during mangrove forest conversion to other land uses. To better quantify the rate of soil organic matter development beneath created, maturing mangrove forests, we measured ecosystem changes across a 25‐year chronosequence. We compared ecosystem properties in created, maturing mangrove forests to adjacent natural mangrove forests. We also quantified site‐specific changes that occurred between 2010 and 2016. Soil organic matter accumulated rapidly beneath maturing mangrove forests as sandy soils transitioned to organic‐rich soils (peat). Within 25 years, a 20‐cm deep peat layer developed. The time required for created mangrove forests to reach equivalency with natural mangrove forests was estimated as: (1) < 15 years for herbaceous and juvenile vegetation; (2) ~55 years for adult trees; (3) ~25 years for the upper soil layer (0‐10 cm); and (4) ~45‐80 years for the lower soil layer (10‐30 cm). For soil elevation change, the created mangrove forests were equivalent to or surpassed natural mangrove forests within the first five years. A comparison to chronosequence studies from other ecosystems indicates that the rate of soil organic matter accumulation beneath maturing mangrove forests may be among the fastest globally. In most peatland ecosystems, soil organic matter formation occurs slowly (centuries, millennia); however, these results show that mangrove peat formation can occur within decades. Peat development, primarily due to sub‐surface root accumulation, enables mangrove forests to sequester carbon, adjust their elevation relative to sea level, and adapt to changing conditions at the dynamic land‐ocean interface. In the face of climate change and rising sea levels, coastal managers are increasingly concerned with the longevity and functionality of coastal restoration efforts. Our results advance understanding of the pace of ecosystem development in created, maturing mangrove forests, which can improve predictions of mangrove forest responses to global change and ecosystem restoration.

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USGS2019

Temperature mediates secondary dormancy in resting cysts of Pyrodinium bahamense (Dinophyceae)

High‐biomass blooms of the toxic dinoflagellate Pyrodinium bahamense occur most summers in Tampa Bay, Florida, USA, posing a recurring threat to ecosystem health. Like many dinoflagellates, P. bahamense forms immobile resting cysts that can be deposited on the seafloor—creating a seed bank that can retain the organism within the ecosystem and initiate future blooms when cysts germinate. In this study, we examined changes in the dormancy status of cysts collected from Tampa Bay and applied lessons from plant ecology to explore dormancy controls. Pyrodinium bahamense cysts incubated immediately after field collection displayed a seasonal pattern in dormancy and germination that matched the pattern of cell abundance in the water column. Newly deposited (surface) cysts and older (buried) cysts exhibited similar germination patterns, suggesting that a common mechanism regulates dormancy expression in new and mature cysts. Extended cool‐ and warm‐temperature conditioning of field‐collected cysts altered the cycle of dormancy compared with that of cysts in nature, with the duration of cool temperature exposure being the best predictor of when cysts emerged from dormancy. Extended warm conditioning, on the other hand, elicited a return to dormancy, or secondary dormancy, in nondormant cysts. These results directly demonstrate environmental induction of secondary dormancy in dinoflagellates—a mechanism common and thoroughly documented in higher plants with seasonal growth cycles. Our findings support the hypothesis that a seasonal cycle in cyst germination drives P. bahamense bloom periodicity in Tampa Bay and point to environmentally induced secondary dormancy as an important regulatory factor of that cycle.

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USGS2019

Tampa Bay Ocean and Coastal Acidification Monitoring Quality Assurance Project Plan

Coastal acidification caused by eutrophication, freshwater inflow, and upwelling is already affecting many estuaries worldwide and can be exacerbated by ocean acidification that is caused by increasing carbon dioxide in the atmosphere. Effective management, mitigation, and (or) adaptation to the effects of coastal and ocean acidification require careful monitoring of the resulting changes in seawater chemistry. Local, regional, and national agencies and institutions organizing acidification-monitoring and research efforts work toward standardizing data collection and reporting protocols so that data can be shared and compared across regions and synthesized into national assessments. This document describes a Quality Assurance Project Plan for the collection and reporting of seawater chemical and physical data using standardized methods and published best practices relevant for monitoring coastal and ocean acidification. The plan specifically addresses procedures for a joint partnership, the Tampa Bay Ocean and Coastal Acidification Monitoring project, conducted by the U.S. Geological Survey, the U.S. Environmental Protection Agency, and the Tampa Bay Estuary Program in the Tampa Bay estuary, Florida. The plan describes recommended procedures for project organization, sampling process design and methods, data-quality objectives and criteria, data validation and management procedures, and project deliverables.

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USGS2016

Ocean acidification buffering effects of seagrass in Tampa Bay

The Intergovernmental Panel on Climate Change has identified ocean acidification as a critical threat to marine and estuarine species in ocean and coastal ecosystems around the world. However, seagrasses are projected to benefit from elevated atmospheric pCO2, are capable of increasing seawater pH and carbonate mineral saturation states through photosynthesis, and may help buffer against the chemical impacts of ocean acidification. Additionally, dissolution of carbonate sediments may also provide a mechanism for buffering seawater pH. Long-term water quality monitoring data from the Environmental Protection Commission of Hillsborough County indicates that seawater pH has risen since the 1980‘s as seagrass beds have continued to recover since that time. We examined the role of seagrass beds in maintaining and elevating pH and carbonate mineral saturation state in northern and southern Tampa Bay where the percent of carbonate sediments is low (<3%) and high (>40%), respectively. Basic water quality and carbonate system parameters (including pH, total alkalinity, dissolved inorganic carbon, partial pressure of CO2, and carbonate mineral saturation state) were measured over diurnal time periods along transects (50-100 m) including dense and sparse Thalassia testudinum. seagrass beds, deep edge seagrass, and adjacent bare sand bottom. Seagrass density and productivity, sediment composition and hydrodynamic parameters were also measured, concurrently. Results indicate that seagrass beds locally elevate pH by up to 0.5 pH unit and double carbonate mineral saturation states relative to bare sand habitats. Thus, seagrass beds in Tampa Bay may provide refuge for marine organisms from the impacts of ocean acidification.

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USGS2012

Tampa Bay coastal wetlands: nineteenth to twentieth century tidal marsh-to-mangrove conversion

Currently, mangroves dominate the tidal wetlands of Tampa Bay, Florida, but an examination of historic navigation charts revealed dominance of tidal marshes with a mangrove fringe in the 1870s. This study's objective was to conduct a new assessment of wetland change in Tampa Bay by digitizing nineteenth century topographic and public land surveys and comparing these to modern coastal features at four locations. We differentiate between wetland loss, wetland gain through marine transgression, and a wetland conversion from marsh to mangrove. Wetland loss was greatest at study sites to the east and north. Expansion of the intertidal zone through marine transgression, across adjacent low-lying land, was documented primarily near the mouth of the bay. Generally, the bay-wide marsh-to-mangrove ratio reversed from 86:14 to 25:75 in 125 years. Conversion of marsh to mangrove wetlands averaged 72 % at the four sites, ranging from 52 % at Old Tampa Bay to 95 % at Feather Sound. In addition to latitudinal influences, intact wetlands and areas with greater freshwater influence exhibited a lower rate of marsh-to-mangrove conversion. Two sources for nineteenth century coastal landscape were in close agreement, providing an unprecedented view of historic conditions in Tampa Bay.

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USGS2011

Management case study: Tampa Bay, Florida

Tampa Bay, Florida, USA, is a shallow, subtropical estuary that experienced severe cultural eutrophication between the 1940s and 1980s, a period when the human population of its watershed quadrupled. In response, citizen action led to the formation of a public- and private-sector partnership (the Tampa Bay Estuary Program), which adopted a number of management objectives to support the restoration and protection of the bay’s living resources. These included numeric chlorophyll a and water-clarity targets, as well as long-term goals addressing the spatial extent of seagrasses and other selected habitat types, to support estuarine-dependent faunal guilds. Over the past three decades, nitrogen controls involving sources such as wastewater treatment plants, stormwater conveyance systems, fertilizer manufacturing and shipping operations, and power plants have been undertaken to meet these and other management objectives. Cumulatively, these controls have resulted in a 60% reduction in annual total nitrogen (TN) loads relative to earlier worse-case (latter 1970s) conditions. As a result, annual water-clarity and chlorophyll a targets are currently met in most years, and seagrass cover measured in 2008 was the highest recorded since 1950. Factors that have contributed to the observed improvements in Tampa Bay over the past several decades include the following: (1) Development of numeric, science-based water-quality targets to meet a long-term goal of restoring seagrass acreage to 1950s levels. Empirical and mechanistic models found that annual average chlorophyll a concentrations were a primary manageable factor affecting light attenuation. The models also quantified relationships between TN loads, chlorophyll a concentrations, light attenuation, and fluctuations in seagrass cover. The availability of long-term monitoring data, and a systematic process for using the data to evaluate the effectiveness of management actions, has allowed managers to track progress and make adaptive changes when needed. (2) Citizen involvement, that is, the initial reductions in TN loads, which occurred in the late 1970s and early 1980s, was a result of state regulations that were developed in response to citizens’ call for action. Improved water clarity and better fishing and swimming conditions were identified as primary goals by citizens again in the early 1990s, and led to development of numeric water-quality targets and seagrass restoration goals. More recent citizen actions, from pet waste campaigns to support of reductions in residential fertilizer use, are important elements of the nitrogen management strategy. (3) Collaborative actions, that is, in addition to numerous other collaborative ventures that have benefitted Tampa Bay, the public/private Nitrogen Management Consortium, which includes more than 40 participating organizations, has implemented over 250 nutrient-reduction projects. These projects have addressed stormwater treatment, fertilizer manufacturing and shipping, agricultural practices, reclaimed water use, and atmospheric emissions from local power stations, providing more than 300 tons of TN load reductions since 1995. (4) State and federal regulatory programs, that is, regulatory requirements, such as state statutes and rules requiring compliance with advanced wastewater treatment standards by municipal sewerage works, have played a key role in Tampa Bay management efforts. The technical basis and implementation plan of the Tampa Bay nitrogen management strategy have been developed in cooperation with state and federal regulatory agencies, and the strategy has been recognized by them as an appropriate tool for meeting water-quality standards, including federally mandated total maximum daily loads. Subsequent management efforts have focused on maintaining and extending those improvements in Tampa Bay’s environmental resources by addressing water and sediment quality and habitat protection and restoration. Implementation of a collaborative, watershed-based management process, driven by an integrated science approach, has played a central role in supporting progress toward the achievement of science-based estuary management goals.

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USGS2011

Tampa Bay

Tampa Bay is Florida’s largest open-water estuary and encompasses an area of approximately 1036 km 2 (400 mi 2 ) (Burgan and Engle, 2006; TBNEP, 2006). The Bay’s watershed drains 5,698 km 2 (2,200 mi 2 ) of land and includes freshwater from the Hillsborough River to the north east, the Alafia and Little Manatee rivers to the east, and the Manatee River to the south (Figure 1). Freshwater inflow also enters the bay from the Lake Tarpon Canal, from small tidal tributaries, and from watershed runoff. Outflow travels from the upper bay segments (Hillsborough Bay and Old Tampa Bay) into Middle and Lower Tampa Bay. Southwestern portions of the water shed flow through Boca Ciega Bay into the Intracoastal Waterway and through the Southwest Channel and Passage Key Inlet into the Gulf of Mexico. The average depth in most of Tampa Bay is only 3.4 m (11 ft); however, 129 km (80 mi) of shipping channels with a maximum depth of 13.1 m (43 ft) have been dredged over time and are regularly maintained. These channels help to support the three ports within the bay, as well as commercial and recreational boat traffic.

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USGS2007

Seasonal variations on the residence times and partitioning of short-lived radionuclides ( 234 Th, 7 Be and 210 Pb) and depositional fluxes of 7 Be and 210 Pb in Tampa Bay, Florida

Historically, Tampa Bay has been impacted heavily by a wide range of anthropogenic perturbations that may include, agricultural-, shipping-, phosphate mining/distribution-related activities, as well as a burgeoning coastal population. Due to the presence of U-rich underlying sediments, elevated activities of U- and Th-series daughter products may be naturally released into this system. This region is also known for summer thunderstorms and corresponding increases in precipitation and surface water runoff. Only limited work has been conducted on the partitioning of particle-reactive radionuclides (such as 7 Be, 210 Pb, and 234 Th) in such a dynamic coastal system. We investigated both the removal residence time and partitioning of these radionuclides between filter-retained particulate matter (≥ 0.5 μm) and the filtrate (< 0.5 μm) phase during late spring (June 2003) and mid summer (August 2003) in the water column of Tampa Bay. Our results indicate that the partitioning of 7 Be, 210 Pb, and 234 Th between filtrate and filter-retained phase is controlled foremost by enhanced bottom resuspension events during summer thunderstorms. As a consequence, no significant relationship exists between the distribution coefficients (Kd values) of these isotopes and the concentration of suspended particulate matter (SPM). Relatively faster recycling rates of atmospheric water vapor derived from the ocean results in lower atmospheric depositional fluxes of 210 Pb to the study site than predicted. The relationship between 7 Be and 210 Pb in bulk (wet + dry) deposition is compared to their respective water column activities. The residence times of particulate and dissolved 234 Th, 7 Be and 210 Pb, as well the distribution coefficients of these radionuclides, are then compared to values reported in other coastal systems.

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USGS2007

Ra and Rn isotopes as natural tracers of submarine groundwater discharge in Tampa Bay, Florida

A suite of naturally occurring radionuclides in the U/Th decay series ( 222 Rn, 223,224,226,228 Ra) were studied during wet and dry conditions in Tampa Bay, Florida, to evaluate their utility as groundwater discharge tracers, both within the bay proper and within the Alafia River/estuary — a prominent free-flowing river that empties into the bay. In Tampa Bay, almost 30% of the combined riverine inputs still remain ungauged. Consequently, groundwater/surface water (hyporheic) exchange in the discharging coastal rivers, as well as submarine groundwater discharge (SGD) within the bay, are still unresolved components of this system's water and material budgets. Based on known inputs and sinks, there exists an excess of 226 Ra in the water column of Tampa Bay, which can be evaluated in terms of a submarine groundwater contribution to the bay proper. Submarine groundwater discharge rates calculated using a mass balance of excess 226 Ra ranged from 2.2 to 14.5 L m − 2 day − 1 , depending on whether the estuarine residence time was calculated using 224 Ra/xs 228 Ra isotope ratios, or whether a long term, averaged model-derived estuarine residence time was used. When extrapolated to the total shoreline length of the bay, such SGD rates ranged from 1.6 to 10.3 m 3 m − 1 day − 1 . Activities of 222 Rn were also elevated in surface water and shallow groundwater of the bay, as well as in the Alafia River estuary, where upstream activities as high as 250 dpm L − 1 indicate enhanced groundwater/surface water exchange, facilitated by an active spring vent. From average nutrient concentrations of 39 shallow, brackish, groundwater samples, rates of nutrient loading into Tampa Bay by SGD rates were estimated, and these ranged from 0.2 to 1.4 × 10 5 mol day − 1 (PO 4 3− ), 0.9–6.2 × 10 5 mol day − 1 (SiO 4 − ), 0.7–5.0 × 10 5 mol day − 1 (dissolved organic nitrogen, DON), and 0.2–1.4 × 10 6 mol day − 1 (total dissolved nitrogen, TDN). Such nutrient loading estimates, when compared to average river discharge estimates (e.g., TDN = 6.9 × 10 5 mol day − 1 ), suggest that SGD-derived nutrient fluxes to Tampa Bay are indeed important components to the overall nutrient economy of these coastal waters.

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USGS2007

Submarine groundwater discharge to Tampa Bay: Nutrient fluxes and biogeochemistry of the coastal aquifer

To separately quantify the roles of fresh and saline submarine groundwater discharge (SGD), relative to that of rivers, in transporting nutrients to Tampa Bay, Florida, we used three approaches (Darcy's Law calculations, a watershed water budget, and a 222 Rn mass-balance) to estimate rate of SGD from the Pinellas peninsula. Groundwater samples were collected in 69 locations in the coastal aquifer to examine biogeochemical conditions, nutrient concentrations and stoichiometry, and salinity structure. Salinity structure was also examined using stationary electrical resistivity measurements. The coastal aquifer along the Pinellas peninsula was chemically reducing in all locations sampled, and that condition influences nitrogen (N) form and mobility of N and PO 4 3− . Concentrations of NH 4 + , PO 4 3− and ratio of dissolved inorganic N (DIN) to PO 4 3− were all related to measured oxidation/reduction potential (pε) of the groundwater. Ratio of DIN: PO 4 3− was below Redfield ratio in both fresh and saline groundwater. Nitrogen occurred almost exclusively in reduced forms, NH 4 + and dissolved organic nitrogen (DON), suggesting that anthropogenic N is exported from the watershed in those forms. In comparison to other SGD studies, rate of PO 4 3− flux in the seepage zone (μM m − 2 d − 1 ) in Tampa Bay was higher than previous estimates, likely due to 1) high watershed population density, 2) chemically reducing conditions, and 3) high ion concentrations in fresh groundwater. Estimates of freshwater groundwater flux indicate that the ratio of groundwater discharge to stream flow is ∼ 20 to 50%, and that the magnitudes of both the total dissolved nitrogen and PO 4 3− loads due to fresh SGD are ∼ 40 to 100% of loads carried by streams. Estimates of SGD based on radon inventories in near-shore waters were 2 to 5 times greater than the estimates of freshwater groundwater discharge, suggesting that brackish and saline SGD is also an important process in Tampa Bay and results in flux of regenerated N and P from sediment to surface water.

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USGS2007

Colored dissolved organic matter in Tampa Bay, Florida

Absorption and fluorescence of colored dissolved organic matter (CDOM) and concentrations of dissolved organic carbon (DOC), chlorophyll and total suspended solids in Tampa Bay and its adjacent rivers were examined in June and October of 2004. Except in Old Tampa Bay (OTB), the spatial distribution of CDOM showed a conservative relationship with salinity in June, 2004 (a CDOM (400) = − 0.19 × salinity + 6.78, R 2 = 0.98, n = 17, salinity range = 1.1–32.5) with little variations in absorption spectral slope and fluorescence efficiency. This indicates that CDOM distribution was dominated by mixing. In October, 2004, CDOM distribution was nonconservative with an average absorption coefficient (a CDOM (400), ∼ 7.76 m -1 ) about seven times higher than that in June (∼ 1.11 m -1 ). The nonconservative behavior was caused largely by CDOM removal at intermediate salinities (e.g., a CDOM (400) removal > 15% at salinity ∼ 13.0), which likely resulted from photobleaching due to stronger stratification. The spatial and seasonal distributions of CDOM in Tampa Bay showed that the two largest rivers, the Alafia River (AR) and Hillsborough River (HR) were dominant CDOM sources to most of the bay. In OTB, however, CDOM showed distinctive differences: lower absorption coefficient, higher absorption spectral slopes, and lower ratios of CDOM absorption to DOC and higher fluorescence efficiency. These differences may have stemmed from (1) changes in CDOM composition by more intensive photobleaching due to the longer residence time of water mass in OTB; (2) other sources of CDOM than the HR/AR inputs, such as local creeks, streams, groundwater, and/or bottom re-suspension. Average CDOM absorption in Tampa Bay at 443 nm, a CDOM (443), was about five times higher in June and about ten times higher in October than phytoplankton pigment absorption, a ph (443), indicating that blue light attenuation in the water column was dominated by CDOM rather than by phytoplankton absorption throughout the year.

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USGS2007

Deglacial climate variability in central Florida, USA

Pollen and ostracode evidence from lacustrine sediments underlying modern Tampa Bay, Florida, document frequent and abrupt climatic and hydrological events superimposed on deglacial warming in the subtropics. Radiocarbon chronology on well-preserved mollusk shells and pollen residue from core MD02-2579 documents continuous sedimentation in a variety of non-marine habitats in a karst-controlled basin from 20 ka to 11.5 ka. During the last glacial maximum (LGM), much drier and cooler-than-modern conditions are indicated by pollen assemblages enriched in Chenopodiaceae and Carya , with rare Pinus (< 10%). Pinus pollen increased to 20–40% during the warming of the initial deglaciation (∼ 17.2 ka), reaching near modern abundance (60–80%) during warmer, moister climates of the Bølling/Allerød interval (14.7–12.9 ka). Within the Bølling/Allerød, centennial-scale dry events corresponding to the Older Dryas and Intra-Allerød Cold Period indicate rapid vegetation response (< 50 years) to climate variability. The Younger Dryas (12.9–11.6 ka) was characterized by two distinct phases: slightly drier than the peak Bølling/Allerød between 12.9 and 12.3 ka and much drier from 12.3 to 11.5 ka. The Tampa Bay record of deglacial atmospheric temperature and moisture can be correlated with other paleoclimate records in the North Atlantic region and has implications for climate-forcing by ice-sheet fluctuation, thermohaline circulation, and atmospheric circulation.

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USGS2007

Topobathymetric data for Tampa Bay, Florida

Topobathymetric data (“topobathy”) are a merged rendering of both topography (land elevation) and bathymetry (water depth) to provide a single product useful for inundation mapping and a variety of other applications. These data were developed using one topographic and two bathymetric datasets collected at different dates. Topography was obtained from the U.S. Geological Survey's (USGS) National Elevation Dataset (NED). Bathymetry was provided by NOAA's GEOphysical DAta System (GEODAS). For several nearshore areas within the bay GEODAS data were replaced with high resolution bathymetry acquired by NASA's Experimental Advanced Airborne Research Lidar (EAARL).

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USGS2007

Altered mangrove wetlands as habitat for estuarine nekton: are dredged channels and tidal creeks equivalent?

Hasty decisions are often made regarding the restoration of "altered" habitats, when in fact the ecological value of these habitats may be comparable to natural ones. To assess the "value" of altered mangrove-lined habitats for nekton, we sampled for 1 yr within three Tampa Bay wetlands. Species composition, abundance, and spatial distribution of nekton assemblages in permanent subtidal portions of natural tidal creeks and wetlands altered by construction of mosquito-control ditches and stormwater-drainage ditches were quantified through seasonal seine sampling. Results of repeated-measures analysis of variance and ordination of nekton community data suggested differences in species composition and abundance between natural and altered habitat, though not consistently among the three wetlands. In many cases, mosquito ditches were more similar in assemblage structure to tidal creeks than to stormwater ditches. In general, mosquito ditches and stormwater ditches were the most dissimilar in terms of nekton community structure. These dissimilarities were likely due to differences in design between the two types of ditches. Mosquito ditches tend to fill in over time and are thus more ephemeral features in the landscape. In contrast, stormwater ditches are a more permanent altered habitat that remain open due to periodic flushing from heavy runoff. Results indicate that environmental conditions (e.g., salinity, current velocity, vegetative structure) may provide a more useful indication of potential habitat "value" for nekton than whether the habitat has been altered. The type of ditching is therefore more important than ditching per se when judging the habitat quality of these altered channels for fishes, shrimps and crabs. Planning should entail careful consideration of environmental conditions rather than simply restoring for restoration's sake.

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