The condition of coral reefs in South Florida (2000) using coral disease and bleaching as indicators

The destruction of coral reef habitats has occurred at unprecedented levels during the last three decades. Coral disease and bleaching in the Caribbean and South Florida have caused extensive coral mortality with limited recovery, often coral reefs are being replaced with turf algae. Acroporids were once dominant corals and have diminished to the state where they are being considered as endangered species. Our survey assessed the condition of reef corals throughout South Florida. A probability-based design produced unbiased estimates of the spatial extent of ecological condition, measured as the absence or presence and frequency or prevalence of coral diseases and bleaching intensity over large geographic regions. This approach allowed us to calculate a quantifiable level of uncertainty. Coral condition was estimated for 4100 hectares (ha) (or 41.0 km²) of coral reefs in South Florida, including reefs in the Florida Keys National Marine Sanctuary (FKNMS), New Grounds, Dry Tortugas National Park (DTNP), and Biscayne National Park (BNP). The absence or presence of coral disease, causal coral bleaching, partial bleaching and coral paling were not good indicators of overall coral condition. It was more useful to report the prevalence of anomalies that indicated a compromised condition at both the population and community levels. For example, 79% of the area in South Florida had less than 6% of the coral colonies diseased, whereas only 2.2% (97.15 ha) of the sampled area had a maximum prevalence of 13% diseased coral colonies at any single location. The usefulness of causal bleaching might be more important when considering the prevalence of each of the three different states at a single location. For example, paling was observed over the entire area, whereas bleaching and partial bleaching occurred at 19 and 41% of the area, respectively. An index for coral reef condition might integrate the prevalence and species affected by each bleaching state at individual locations. By establishing these baselines, future surveys can examine changes and trends in the spatial distribution of coral conditions in South Florida and able to score the reefs as to their health status.     

The influence of mass transfer on solute transport in column experiments with an aggregated soil

The spreading of concentration fronts in dynamic column experiments conducted with a porous, aggregated soil is analyzed by means of a previously documented transport model (DFPSDM) that accounts for longitudinal dispersion, external mass transfer in the boundary layer surrounding the aggregate particles, and diffusion in the intra-aggregate pores. The data are drawn from a previous report on the transport of tritiated water, chloride, and calcium ion in a column filled with Ione soil having an average aggregate particle diameter of 0.34 cm, at pore water velocities from 3 to 143 cm/h. The parameters for dispersion, external mass transfer, and internal diffusion were predicted for the experimental conditions by means of generalized correlations, independent of the column data. The predicted degree of solute front-spreading agreed well with the experimental observations. Consistent with the aggregate porosity of 45%, the tortuosity factor for internal pore diffusion was approximately equal to 2. Quantitative criteria for the spreading influence of the three mechanisms are evaluated with respect to the column data. Hydrodynamic dispersion is thought to have governed the front shape in the experiments at low velocity, and internal pore diffusion is believed to have dominated at high velocity; the external mass transfer resistance played a minor role under all conditions. A transport model such as DFPSDM is useful for interpreting column data with regard to the mechanisms controlling concentration front dynamics, but care must be exercised to avoid confounding the effects of the relevant processes.     

Catfish epidermal secretions in response to threat or injury

The Arabian Gulf catfish (Arius thalassinus, Rüppell) secrete a thick layer of proteinaceous material when threatened or injured. The chemical and pharmacological properties of this material indicate that it may promote the healing of wounds. These studies suggest that the abrupt secretion of mucous-like gel in response to a perceived hazard is an externally expressed defense response; the secretion may have a primary function in healing injury beyond the commonly postulated roles of deterring predators or facilitating escape.     

Improving PHA/LOPA by consistent consequence severity estimation

Most risk analysis methods rely on a qualitative judgment of consequence severity, regardless of the analysis rigor applied to the estimation of hazardous event frequency. Since the risk analysis is dependent on the estimated frequency and consequence severity of the hazardous event, the error associated with the consequence severity estimate directly impacts the estimated risk and ultimately the risk reduction requirements. Overstatement of the consequence severity creates excessive risk reduction requirements. Understatement results in inadequate risk reduction.Consistency in the consequence severity estimate can be substantially improved by implementing consequence estimation tools that assist PHA/LOPA team members in understanding the flammability, explosivity, or toxicity of process chemical releases. This paper provides justification for developing semi-quantitative look-up tables to support the team assessment of consequence severity. Just as the frequency and risk reduction tables have greatly improved consistency in the estimate of the hazardous event frequency, consequence severity tables can significantly increase confidence in the severity estimate.     

A Review of the Elements of Human Well-Being with an Emphasis on the Contribution of Ecosystem Services

Natural ecosystems perform fundamental life-support services upon which human civilization depends. However, many people believe that nature provides these services for free and therefore, they are of little or no value. While we do not pay for them, we pay significantly for their loss in terms of wastewater treatment facilities, moratoriums on greenhouse gases, increased illnesses, reduced soil fertility and losses in those images of nature that contribute to our basic happiness. Little is understood about the well-being benefits of the natural environment and its ecosystem services. The interwoven relationship of ecosystems and human well-being is insufficiently acknowledged in the wider philosophical, social, and economic well-being literature. In this article, we discuss an approach to examine human well-being and the interactions of its four primary elements-basic human needs, economic needs, environmental needs, and subjective well-being-and ecosystem services.     

The Role of Social and Intergenerational Equity in Making Changes in Human Well-Being Sustainable

A sustainable world is one in which human needs are met equitably and without sacrificing the ability of future generations to meet their needs. Human well-being is described by four primary elements—basic human needs, economic needs, environmental needs, and subjective well-being. These elements can interact in a myriad of ways to influence overall well-being. What makes changes in human well-being sustainable for a population or a nation? Two major interactional concepts can push changes in human well-being toward a sustainable state in space and time—social equity and intergenerational equity. The concept of social equity distributes well-being over space, ensuring the fair treatment of all members of society promoting spatial sustainability of a well-being decision. The concept of intergenerational equity distributes well-being through time, ensuring the well-being of present and future generations of a population or nation, promoting temporal sustainability of a well-being decision. The roles of social and intergenerational equity in terms of their influence on human well-being are examined with a focus on more sustainable decision-making.     

Using structural equation modeling to investigate relationships among ecological variables

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.     

Dissolved Oxygen Conditions in Northern Gulf of Mexico Estuaries

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.     

The Ecological Condition of Gulf of Mexico Resources from Perdido Key to Port St. Joe, Florida, USA: Part I. Coastal Beach Resources

Using the approach established by EPA's Environmental Monitoring and Assessment Program (EMAP), a shoreline monitoring survey was conducted in August and September 1999, encompassing the Florida Panhandle from Perdido Key, Florida to Port St. Joe, Florida. The objective of this survey was to demonstrate the use of a probabilistic survey for monitoring and estimating the condition of swimmable beach areas. Thirty stations were sampled using a probabilistic sampling design. Hydrographic data were collected in addition to samples for water chemistry. Bacterial indicators, enterococci and fecal coliforms, were enumerated from the water according to the EPA Beaches Environmental Assessment Closure and Health (BEACH) Program and Florida state guidelines. Additional criteria for site condition included the presence or absence of primary and secondary dunes, anthropogenic debris and vegetation. Based on EMAP evaluation guidelines and Florida state criteria, a baseline assessment of the condition of the Gulf of Mexico beach resources surveyed is presented.