Evaluating the causal basis of ecological success within the scleractinia: an integral projection model approach

Many tropical corals have declined in abundance in the last few decades, and evaluating the causal basis of these losses is critical to understanding how coral reefs will change in response to ongoing environmental challenges. Motivated by the likelihood that marine environments will become increasingly unfavorable for coral growth as they warm and become more acidic (i.e., ocean acidification), it is reasonable to evaluate whether specific phenotypic traits of the coral holobiont are associated with ecological success (or failure) under varying environmental conditions including those that are adverse to survival. Initially, we asked whether it was possible to identify corals that are resistant or sensitive to such conditions by compiling quantitative measures of their phenotypic traits determined through empirical studies, but we found only weak phenotypic discrimination between ecological winners and losers, or among taxa. To reconcile this outcome with ecological evidence demonstrating that coral taxa are functionally unequal, we looked beyond the notion that phenotypic homogeneity arose through limitations of empirical data. Instead, we examined the validity of contemporary means of categorizing corals based on ecological success. As an alternative means to distinguish among functional groups of corals, we present a demographic approach using integral projection models (IPMs) that link organismal performance to demographic outcomes, such as the rates of population growth and responses to environmental stress. We describe how IPMs can be applied to corals so that future research can evaluate within a quantitative framework the extent to which changes in physiological performance influence the demographic underpinnings of ecological performance.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

An experimental evaluation of transgenerational isotope labelling in a coral reef grouper

Transgenerational isotope labelling (TRAIL) using enriched stable isotopes provides a novel means of mass-marking marine fish larvae and estimating larval dispersal. The technique, therefore, provides a new way of addressing questions about demographic population connectivity and larval export from no-take marine protected areas. However, successful field applications must be preceded by larval rearing studies that validate the geochemical marking technique, determine appropriate concentrations and demonstrate that larvae are not adversely affected. Here, we test whether injection of enriched stable barium isotopes (¹³⁵Ba and ¹³⁷Ba) at two dose rates produces unequivocal marks on the otoliths of the coral reef grouper Epinephelus fuscoguttatus. We also assess potential negative effects on reproductive performance, egg size, condition and larval growth due to injection of adult female fish. The injection of barium isotopes at both 0.5 and 2.0 mg Ba/kg body weight into the body cavities of gravid female fish was 100% successful in the geochemical tagging of the otoliths of larvae from the first spawning after injection. The low-dose rate produced no negative effects on eggs or larvae. However, the higher dose rate of 2 mg Ba/kg produced small reductions in yolk sac area, oil globule area, standard length and head depth of pre-feeding larvae. Given the success of the 0.5 mg Ba/kg dose rate, it is clearly possible to produce a reliable mark and keep the concentration below any level that could affect larval growth or survival. Hence, enriched Ba isotope injections will provide an effective means of mass-marking grouper larvae.     

Distribution of tritium in estuarine waters: the role of organic matter

Tritium is an important environmental radionuclide whose reactivity with ligands and solids in aquatic systems is assumed to be limited. We studied the fractionation and sorption of tritium (added as tritiated water) in river water and seawater, and found that its distribution appears to be influenced by its affinity for organic matter. Tritium rapidly equilibrates with dissolved organic ligands that are retained by a reverse-phase C18 column, and with suspended sediment particles. Significantly, a measurable fraction of sorbed tritium associates with proteinaceous material that is potentially available to sediment-feeding organisms. These characteristics have not been reported previously and cannot be accounted for solely by isotopic exchange with hydrogen. Nevertheless, they are in qualitative agreement with available measurements of tritium in estuarine and coastal waters where its principal discharge is as tritiated water. Further research into the estuarine biogeochemical behaviour of tritium is required and radiological distribution coefficients and concentration factors that are assumed for this radionuclide may require reconsideration.     

Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation

This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L^?1). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption–oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.     

Mobility and recalcitrance of organo-chromium(III) complexes

Hexavalent chromium [Cr(VI)] is a major industrial pollutant. Bioremediation of Cr(VI) to Cr(III) is a viable clean-up approach. However, Cr(VI) bioreduction also produces soluble organo–Cr(III) complexes, and little is known about their behavior in the environment. When tested with soil columns, citrate–Cr(III) showed little sorption to soil; malate–Cr(III) had limited partitioning with soil; and histidine–Cr(III) exhibited significant interaction with soil. It appears that the mobility varies depending on the organic ligand. Further, Ralstonia eutropha JMP 134 and Pseudomonas aeruginosa pAO1 readily degraded malate, citrate, and histidine, but not the corresponding organo–Cr(III) complexes. The recalcitrance is not due to toxicity, but the complexes are likely to cause hindrance to enzymes, as malate dehydrogenase and amino acid oxidase could not use malate–Cr(III) and histidine–Cr(III), respectively. The data are in agreement with the reports of soluble organo–Cr(III) complexes in the environment.     

Nonferrous metal (loid) s mediate bacterial diversity in an abandoned mine tailing impoundment

Environmental Science and Pollution Research - Migration and transformation of toxic metal (loid) s in tailing sites inevitably lead to ecological disturbances and serious threats to the...     

The SITE Demonstration of the Shirco Electric Infrared Incinerator

A test program for the Shirco infrared destruction process is described in this article. This incineration process is transportable and can be an effective method for cleanup of soils from Superfund sites. A pilot-scale unit and a 100-ton per day transportable unit were tested as part of the Superfund Technology Evaluation (SITE) program.

The process consists of a thermal destruction chamber where electricity is used for infrared rods that heat the waste, and a second chamber where propane is used to destroy any remaining hydrocarbons in the exhaust from the first chamber. A venturi scrubber and horizontal packed tower were used for particulate removal before exhausting the gas to the atmosphere. The feed material was reduced to less than one inch in diameter before it was processed by the unit.

The testing indicated that the Shirco system would remove and destroy organics from a waste, but would not remove heavy metals. The scrubber on the full scale system was of marginal capacity for that particular application and did not meet the RCRA specifications of 180 mg/dscm during two of the four tests made for the full scale unit.

Both units achieved Destruction and Removal Efficiencies (DRE) in excess of the 99.99 percent required for RCRA applications. Performance with respect to the TSCA requirement of 99.9999 percent for PCBs could not be ascertained due to the concentration of PCB in the feed.     

Facilitating Integrated Resource and Environmental Management: Australian and Canadian Perspectives

It is widely believed that improved resource and environmental management outcomes would occur if those responsible took a longer term view, considered whole systems rather than their components in isolation, and co-ordinated and integrated their activities with each other. There has been substantial action in many countries to achieve these ideals but with mixed success. Why has it not been possible to have a more co-ordinated and integrated approach to resource and environmental management (IREM)? We briefly review various conceptual issues regarding the purpose and character of IREM. The core of the paper is analysis of the factors contributing to success or failure, including the requirement that IREM, in practice, must be based on a careful analysis of the need and scope for integration in a given context, the significance of leadership, information access, and the links with other planning and management activities. Obstacles arising from these and other shortcomings, including the focus regarding what IREM involves, bureaucratic resistance, adverse financial arrangements and property rights problems, are also discussed. The paper concludes with five recommendations as to how to enhance integrated resource and environmental management dealing with need, scope and context, best management practice, information accessibility and integration, financial arrangements,and strengthening local and regional planning capacity.