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  • 1
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    Ecological condition of coastal ocean and estuarine waters of the U.S. South Atlantic Bight: 2000-2004 (2021)
    NOAA/National Ocean Service | Charleston, SC
    In:  http://aquaticcommons.org/id/eprint/14625 | 403 | 2014-02-21 21:36:16 | 14625 | United States National Ocean Service
    Details
    Publication Date: 2021-06-30
    Description: In March-April 2004, the National Oceanic and Atmospheric Administration (NOAA), U.S. Environmental Protection Agency (EPA), and State of Florida (FL) conducted a study to assessthe status of ecological condition and stressor impacts throughout the South Atlantic Bight (SAB) portion of the U.S. continental shelf and to provide this information as a baseline for evaluating future changes due to natural or human-induced disturbances. The boundaries of thestudy region extended from Cape Hatteras, North Carolina to West Palm Beach, Florida and from navigable depths along the shoreline seaward to the shelf break (~100m). The studyincorporated standard methods and indicators applied in previous national coastal monitoring programs — Environmental Monitoring and Assessment Program (EMAP) and National Coastal Assessment (NCA) — including multiple measures of water quality, sediment quality, andbiological condition. Synoptic sampling of the various indicators provided an integrative weight-of-evidence approach to assessing condition at each station and a basis for examining potential associations between presence of stressors and biological responses. A probabilisticsampling design, which included 50 stations distributed randomly throughout the region, was used to provide a basis for estimating the spatial extent of condition relative to the various measured indicators and corresponding assessment endpoints (where available).Conditions of these offshore waters are compared to those of southeastern estuaries, based on data from similar EMAP/NCA surveys conducted in 2000-2004 by EPA, NOAA, and partnering southeastern states (Florida, Georgia, South Carolina, North Carolina, Virginia) (NCA database for estuaries, EPA Gulf Ecology Division, Gulf Breeze FL). Data from a total of 747 estuarine stations are included in this database. As for the offshore sites, the estuarine samples were collected using standard methods and indicators applied in previous coastal EMAP/NCA surveys including the probabilistic sampling design and multiple indicators of water quality, sediment quality, and biological condition (benthos and fish).The majority of the SAB had high levels of DO in near-bottom water (〉 5 mg L-1) indicative of "good" water quality. DO levels in bottom waters exceeded this upper threshold at all sites throughout the coastal-ocean survey area and in 76% of estuarine waters. Twenty-one percent ofestuarine bottom waters had moderate levels of DO between 2 and 5 mg L-1 and 3% had DO levels below 2 mg L-1. The majority of sites with DO in the low range considered to be hypoxic (〈 2 mg L-1) occurred in North Carolina estuaries. There also was a notable concentration of stations with moderate DO levels (2 – 5 mg L-1) in Georgia and South Carolina estuaries.Approximately 58% of the estuarine area had moderate levels of chlorophyll a (5-10 μg L-1) and about 8% of the area had higher levels, in excess of 10 μg L-1, indicative of eutrophication. The elevated chlorophyll a levels appeared to be widespread throughout the estuaries of the region.In contrast, offshore waters throughout the region had relatively low levels of chlorophyll a with 100% of the offshore survey area having values 〈 5 μg L-1.
    Description: EPA 600/R-10/046
    Keywords: Biology ; Ecology ; Fisheries ; Management
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 88
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  • 2
    Electronic Resource
    Electronic Resource
    Biogeography of benthic macroinvertebrates in estuaries along the Gulf of Mexico and western Atlantic coasts1,2 (2000)
    Springer
    Hydrobiologia 436 (2000), S. 17-33 
    Details
    ISSN: 1573-5117
    Keywords: biogeography ; estuary ; benthic ; invertebrate ; province
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The community composition of benthic macroinvertebrates from 870 estuarine sites was examined in order to either confirm or challenge established boundaries of biogeographical provinces along the Gulf of Mexico and western Atlantic coasts of the United States. The objective was two-fold: (1) to demarcate boundaries that separate dissimilar fauna in the Gulf of Mexico, and (2) to compare the Gulf of Mexico biogeographically with other well-known provinces. We segmented the coastline into grid cells with dimensions of 1° latitude and 2–4° longitude. Using the descriptive techniques of cluster analysis and nonmetric multidimensional scaling, we determined the similarities in benthic community composition between sites within grid cells in the Gulf of Mexico and compared the biotic ordinations to natural habitat characteristics such as salinity, sediment type, and depth. We then evaluated the overall community composition within each grid cell in the Gulf of Mexico and established whether or not similarities existed between adjacent grid cells. In this manner, we confirmed that an east–west gradient existed in estuarine benthic community composition along the Gulf of Mexico coast. This information was combined with our previous work in the western Atlantic coast to discern biogeographical provinces. Based on cluster analyses and an analysis of endemic benthic species the following provinces are proposed: (1) the Virginian province, from Cape Cod, Massachusetts to Wilmington, North Carolina, (2) the Gulf of Mexico, from Rio Grande, Texas to Cape Romano, Florida, and (3) south Florida, south of latitude 26° N. The region encompassing South Carolina, Georgia and northern Florida represents a transitional area between temperate and tropical provinces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026572601578
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  • 3
    Electronic Resource
    Electronic Resource
    Evaluation of sampling strategies to characterize dissolved oxygen conditions in northern Gulf of Mexico estuaries (1993)
    Springer
    Environmental monitoring and assessment 24 (1993), S. 219-229 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Dissolved oxygen was continuously monitored in eight sites of northern Gulf of Mexico estuaries in August, 1990. Monte Carlo analyses on subsamples of the data were used to evaluate several commonly used monitoring strategies. Monitoring strategies which involve single point sampling of dissolved oxygen may often misclassify an estuary as having good water quality. In the case of shallow, often well-mixed estuaries that experience diurnal cycles, such monitoring often does not occur at night, during the time of lowest dissolved oxygen concentration. Our objective was to determine the minimum sampling effort required to correctly classify a site in terms of the observed frequency of hypoxia. Tests concluded that the most successful classification strategy used the minimum dissolved oxygen concentration from a continuously sampled 24-hour period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00545979
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  • 4
    Electronic Resource
    Electronic Resource
    Linking Monitoring and Effects Research: EMAP's Intensive Site Network Program (1998)
    Springer
    Environmental monitoring and assessment 51 (1998), S. 369-380 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The EMAP program has been organized into three primary elements: Multi-Tier Design, Indicators, and Index Sites. The Index Sites program (DISPro - Demonstration Intensive Site Project) is the primary activity within the Index Sites element of EMAP. This project represents an inter-agency effort between EPA/ORD and DOI/NPS to develop a demonstration of an intensive site network of monitoring and research locations throughout the United States, utilizing the Nation's parklands as "outdoor laboratories." Twelve parks were selected to establish this demonstration. These 12 parks were selected because they are readily accessible, have a history of monitoring environmental information, and represent a broad spectrum of ecological communities. EMAP, through DISPro, is examining whether a "network" of sites existing within the parks can be used to address monitoring issues for global-scale environmental stressors (e.g., air pollution) as well as locale-specific stressors (e.g., air deposition, water-borne) and coordinated with cause-effect, issue-based research related to these environmental stressors. As a first activity, EPA will provide each of the sites with the instrumentation to monitor UV-B. The intent of the program is to initiate a consistent air monitoring program at each site to be followed by consistent monitoring within other media. The project will initiate research projects at all the sites (eventually) to examine the effects of environmental stressors of importance at each of the sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005976412512
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  • 5
    Electronic Resource
    Electronic Resource
    Dissolved Oxygen Conditions in Northern Gulf of Mexico Estuaries (1999)
    Springer
    Environmental monitoring and assessment 57 (1999), S. 1-20 
    Details
    ISSN: 1573-2959
    Keywords: dissolved oxygen ; EMAP ; estuary ; Gulf of Mexico ; monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Because deficient dissolved oxygen (DO) levels may have severe detrimental effects on estuarine and marine life, DO has been widely used as an indicator of ecological conditions by environmental monitoring programs. The U.S. EPA's Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) monitored DO conditions in the estuaries of the Gulf of Mexico from 1991 to 1994. DO was measured in two ways: 1) instantaneous profiles from the surface to the bottom were taken during the day, and 2) continuous measurements were taken near the bottom at 15 min intervals for at least 12 h. This information was summarized to assess the spatial distribution and severity of DO conditions in these estuaries. Depending on the criteria used to define hypoxia (DO concentrations usually 〈2 mg L-1 or 〈5 mg L-1) and the method by which DO is measured, we estimate that between 5.2 and 29.3% of the total estuarine area in the Louisianian Province was affected by low DO conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005980410752
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  • 6
    Electronic Resource
    Electronic Resource
    Using structural equation modeling to investigate relationships among ecological variables (2000)
    Springer
    Environmental and ecological statistics 7 (2000), S. 93-111 
    Details
    ISSN: 1573-3009
    Keywords: exploratory and confirmatory factor analysis ; indicator variables ; latent variables ; measurement errors ; measurement models ; path analysis ; regression analysis ; structural equation modeling ; structural models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Structural equation modeling is an advanced multivariate statistical process with which a researcher can construct theoretical concepts, test their measurement reliability, hypothesize and test a theory about their relationships, take into account measurement errors, and consider both direct and indirect effects of variables on one another. Latent variables are theoretical concepts that unite phenomena under a single term, e.g., ecosystem health, environmental condition, and pollution (Bollen, 1989). Latent variables are not measured directly but can be expressed in terms of one or more directly measurable variables called indicators. For some researchers, defining, constructing, and examining the validity of latent variables may be the end task of itself. For others, testing hypothesized relationships of latent variables may be of interest. We analyzed the correlation matrix of eleven environmental variables from the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) using methods of structural equation modeling. We hypothesized and tested a conceptual model to characterize the interdependencies between four latent variables-sediment contamination, natural variability, biodiversity, and growth potential. In particular, we were interested in measuring the direct, indirect, and total effects of sediment contamination and natural variability on biodiversity and growth potential. The model fit the data well and accounted for 81% of the variability in biodiversity and 69% of the variability in growth potential. It revealed a positive total effect of natural variability on growth potential that otherwise would have been judged negative had we not considered indirect effects. That is, natural variability had a negative direct effect on growth potential of magnitude −0.3251 and a positive indirect effect mediated through biodiversity of magnitude 0.4509, yielding a net positive total effect of 0.1258. Natural variability had a positive direct effect on biodiversity of magnitude 0.5347 and a negative indirect effect mediated through growth potential of magnitude −0.1105 yielding a positive total effects of magnitude 0.4242. Sediment contamination had a negative direct effect on biodiversity of magnitude −0.1956 and a negative indirect effect on growth potential via biodiversity of magnitude −0.067. Biodiversity had a positive effect on growth potential of magnitude 0.8432, and growth potential had a positive effect on biodiversity of magnitude 0.3398. The correlation between biodiversity and growth potential was estimated at 0.7658 and that between sediment contamination and natural variability at −0.3769.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009662930292
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  • 7
    Electronic Resource
    Electronic Resource
    Determining the Causes of Benthic Condition (1998)
    Springer
    Environmental monitoring and assessment 51 (1998), S. 381-397 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A benthic index for northern Gulf of Mexico estuaries has been developed and successfully validated by the Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) in the Louisianian Province. The benthic index is a useful and valid indicator of estuarine condition that is intended to provide environmental managers with a simple tool for assessing the ecological condition of benthic macroinvertebrate communities. Associations between the benthic index and indicators of hypoxia, sediment contamination, and sediment toxicity were investigated to determine the most probable cause(s) of degraded benthic condition. The results showed that, on a local scale, the associations between the benthic index and potential environmental causes differed among estuaries. In Pensacola Bay, FL, for example, there was a significant association between the levels of toxic chemicals (e.g. DDT, silver, and TBT) in the sediment and the benthic index, especially in the bayous which have known sediment contamination problems. In Mobile Bay, however, degraded benthic communities were more closely associated with eutrophication and hypoxia. Nevertheless, a benthic index is a valuable tool for identifying areas that could be already degraded and tracking the status of environmental condition in large geographical regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005932630259
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  • 8
    Electronic Resource
    Electronic Resource
    Using Information on Spatial Variability of Small Estuaries in Designing Large-Scale Estuarine Monitoring Programs (2000)
    Springer
    Environmental monitoring and assessment 63 (2000), S. 223-236 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract In the early 1990s, EPA's Environmental Monitoring and Assessment Program (EMAP) documented the ecological condition of the overall population of small estuaries along the mid-Atlantic coast of the United States. However, the Program did not provide detailed information on the condition of individual estuaries less than 260 km2 in surface area, a group of estuaries of concern to environmental managers. To address the needs of environmental managers, when EMAP returned to the region in summer 1997, it included a study of the spatial variability of ecological indicators within individual small estuaries. At 127 probability-based sites in 10 estuaries, EMAP measured a variety of parameters of water quality and sediments, including dissolved oxygen (DO), nutrients, grain size of sediments, contaminants in sediments, and community structures of benthic macroinvertebrates. From this information the ecological condition (e.g., percent area with DO concentrations below 5mg L−1) for each estuary, along with 90% confidence interval, was determined. The width of the confidence interval was then recalculated for sample sizes ranging from two stations to the total number of stations sampled in that estuary. Confidence interval widths were then plotted against sample size. These plots can be useful in designing future regional monitoring programs with a goal of describing conditions in individual systems as well as broad geographic regions. Results illustrate that beyond five stations per estuary, the reduction in the width of the confidence interval with increasing sampling intensity is relatively small; however, individual program managers need to determine "how small is small enough."
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006408306208
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  • 9
    Electronic Resource
    Electronic Resource
    Design-based estimators and power analyses of trend tests for the proportion of fish that exhibit gross pathological disorders (1998)
    Springer
    Environmental and ecological statistics 5 (1998), S. 65-80 
    Details
    ISSN: 1573-3009
    Keywords: estuaries ; fish ; pathology ; variance estimation ; power analyses ; Horvitz-Thompson estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Methods for estimating the proportion of fish that exhibit gross pathological disorders and for estimating the variance of these estimates are defined. The methods are for the situation in which a probability-based sampling design is used to collect fish for examination, but geographic locations (rather than individual fish) are assigned probabilities of being selected for sampling. To illustrate the use of the methods, they are applied to data collected during the 1992 EMAP- Estuaries sampling program in the Louisianian Province (i.e., the Gulf of Mexico). Separate estimates of the proportion of fish with gross pathological disorders are computed for demersal species, commercial species, pelagic species, and all species as one group. In addition, a test for trend in the proportion of fish that exhibit gross pathological disorders is defined, and analyses of the power of the test are presented. The power analyses are based on a general underlying model of the random distribution patterns of fish and the random process of catching fish. The power analyses also take into account the features of the sampling designs used for collecting fish. Component parameter estimates were computed using data from the 1992 EMAP-Estuaries sampling program in the Louisianian Province. Results from these analyses suggest that the EMAP-Estuaries sampling designs are capable of detecting a 0.15% change per year in the proportion of fish (all species groups combined) with gross pathological disorders in estuaries of the Louisianian Province over a 12-year period with a power of at least 80%. © Rapid Science 1998
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009611520486
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  • 10
    Electronic Resource
    Electronic Resource
    CHARACTERIZING DISSOLVED OXYGEN CONDITIONS IN ESTUARINE ENVIRONMENTS (1997)
    Springer
    Environmental monitoring and assessment 45 (1997), S. 321-330 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Dissolved oxygen concentration, which is often measured inestuaries to quantify the results of and stresses associatedwith eutrophication, can be highly variable with time of dayand tidal stage. To assess how well dissolved oxygenconditions are characterized by typical monitoring programs,we conducted Monte Carlo sampling from 16 semi-continuous,31-day dissolved oxygen records collected from estuaries alongthe Atlantic and Gulf coasts to mimic three samplingstrategies: (1) systematic point-in-time sampling, (2) randompoint-in-time sampling, and (3) short-term continuous records.These strategies were evaluated for their accuracy inestimating mean oxygen concentration, minimum oxygenconcentration, and percent of time below a threshold value of2 ppm. Mean dissolved oxygen concentration was most accuratelyestimated in both estuarine regions by random point-in-timesampling, but this strategy required more than ten samplingsper month for the estimate to be within 0.5 ppm on 50% of thesimulations. Short-term continuous sampling (24–48 h)correctly identified estuaries in the Gulf of Mexico regionwhere dissolved oxygen concentrations of less than 2 ppm wereexperienced greater than 20% of the time. However, largetidal variations in Atlantic coast estuaries showed thismeasure to be inaccurate in these estuarine environments. Noneof the sampling strategies correctly identified month-longoxygen minima within 0.5 ppm for more than 50% of thesimulations. This inability to characterize correctlydissolved oxygen conditions could add significant uncertaintyto risk assessments, waste load allocation models, and otherwater quality evaluations that are the basis for developingwastewater treatment strategies and requirements. Perhaps moreimportantly, the inaccuracy with which conventional samplingprocedures characterize minimum dissolved oxygen valuessuggests that the extent of hypoxia in estuarine waters inbeing substantially underestimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005726718951
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