Response of balanced network models to large-scale perturbation: Implications for evaluating the role of small pelagics in the Gulf of Maine

Exploring the response of an ecosystem, and subsequent tradeoffs among its biological community, to human perturbations remains a key challenge for the implementation of an ecosystem approaches to fisheries (EAF). To address this and related issues, we developed two network (or energy budget) models, Ecopath and Econetwrk, for the Gulf of Maine ecosystem. These models included 31 network “nodes” or biomass state variables across a broad range of trophic levels, with the present emphasis to particularly elucidate the role of small pelagics. After initial network balancing, various perturbation scenarios were evaluated to explore how potential changes to different fish, fisheries and lower trophic levels can affect model outputs. Categorically across all scenarios and interpretations thereof, there was minimal change at the second trophic levels and most of the “rebalancing” after a perturbation occurred via alteration of the diet matrix. Yet the model results from perturbations to a balanced energy budget fall into one of three categories. First, some model results were intuitive and in obvious agreement with established ecological and fishing theory. Second, some model results were counter-intuitive upon initial observation, seemingly contradictory to known ecological and fishing theory; but upon further examination the results were explainable given the constraints of an equilibrium energy budget. Finally, some results were counter-intuitive and difficult to reconcile with theory or further examination of equilibrium constraints. A detailed accounting of biomass flows for example scenarios explores some of the non-intuitive results more rigorously. Collectively these results imply a need to carefully track biomass flows and results of any given perturbation and to critically evaluate the conditions under which a new equilibrium is obtained for these types of models, which has implications for dynamic simulations based off of them. Given these caveats, the role of small pelagics as a prominent component of this ecosystem remains a robust conclusion. We discuss how one might use this approach in the context of further developing an EAF, recognizing that a more holistic, integrated perspective will be required as we continue to evaluate tradeoffs among marine biological communities.     

Plume analysis from field evaluations of a portable air quality monitoring system

ABSTRACT

Near-road measurements in Rochester, NY with a Portable Air Quality Monitoring System indicate a significant plume control of PM_2.5 black carbon (BC) concentrations. This study evaluates the performance of two portable air quality enclosures deployed at collocated research sites to determine their accuracy and usefulness in field deployments, and specifically in pollution plume analysis. One system deployed collocated sensors for measurement of particulate matter mass concentration (Thermo pDR 1500 against Tapered Element Oscillating Microbalance (TEOM) measurement) and the second system deployed sensors for measurement of black carbon (Magee AE33 aethalometer and Brechtel Tricolor Absorption Photometer) in ambient and near-road locations in Rochester, New York, respectively. While the optical PM_2.5 sensors tended to be biased in their determination of concentration by ~15%, they followed changes and trends in concentration very well. The black carbon sensors in the portable systems agreed very well with each other and with the collocated sensor. As a case study to determine the contribution from statistically significant short-lived excursions of pollutant concentration, Morlet wavelet analysis was performed on data from the portable system sensors. Black carbon was found to be strongly influenced by plume behavior with significant plume excursions representing just over 12% of all data points and contributing on average 1 µg/m³ of black carbon above ambient concentrations.

Implications: This paper first evaluates two air pollutant monitoring enclosures with wide applicability including near-road detection of pollutants. Then, we present a novel method to designate isolate statistically significant excursions in air pollution concentration which can be used to determine the impact of pollutant plumes as observed in PM and black carbon behavior near road.     

Integration of RBCA frameworks and remediation technologies

Decisions that determine the proper risk-based remediation approach are based on technical, regulatory, cost, legal, and political factors. A wide variety of options such as the ASTM RBCA tiered approach, the API Decision Support Software, and a host of agency-specific methods and commercial risk assessment software are all available. The optimization of a remediation project requires the right remediation technology coupled with the appropriate analytical framework. For groundwater remediation, the application of various “risk reduction” technologies can be classified as aggressive (pump and treat), moderate intensity (air sparging), low intensity (oxygen release compound-ORC®), and intrinsic (monitor only). The time frame of risk analysis will establish the proper risk reduction strategy. The selection process is inherently iterative, and the approach by which an optimal solution can be derived forms the basis of this article. A case study of a Texas site put these issues into context.     

Experimental research on race and sex discrimination: The record and the prospects

Research in industry regarding race and sex access discrimination is reviewed. Review of sex discrimination research suggests that negative access discrimination exists for female applicants when the position is male-stereotyped and positive access discrimination exists when it is female-stereotyped. Results on race discrimination are few in number with mixed results, some showing reverse discrimination and others showing discrimination against blacks. More complex studies examining interactions between race and sex also provide mixed results. Recent evidence, which suggests that selection decisions are much more complex than have been studied, may account for the conflicting findings. Future research with more imaginative and complex designs and larger sample sizes is needed. Research designs should be selected to facilitate better measurement of the effects of civil rights law enforcement.     

The nexus amid foreign direct investment,urbanization, and CO2 emissions: Evidence from energy grouping along the ECOWAS community

Environment, Development and Sustainability - The vision of every country or subregions is to achieve economic growth and sustainable economic growth. Thus, the Economic Community of West African...     

Distributional effects of environmental policies in Greece

Environmental protection policies generate an equity question concerning the fair allocation of environmental benefits and costs. This paper presents evidence from Greece during the 1980s. The findings reveal that Greek environmental policies, in the form of government self-regulatory programs, are mostly regressive in nature. At the regional level these programs combine all forms of vertical equity. Since the public sector finances the majority of related expenditures out of taxes, the regressive elements of environmental policies have been reinforced by discretionary fiscal measures and tax evasion, accompanied by inflation, which have distorted the country's progressive tax system.     

Estimating the costs of corrective action at land disposal facilities

The U.S. Environmental Protection Agency (EPA) has proposed regulations that would require corrective action (e.g., soil excavation and groundwater removal and treatment) at municipal solid waste landfills (MSWLFs) and hazardous waste treatment, storage, and disposal facilities (TSDFs). This paper presents an overview of the proposed corrective action regulations, and discusses their relationship to proposed or existing closure and post-closure care regulations. The paper then presents estimated corrective action cost curves for various MSWLF scenarios defined by landfill area, average waste thickness, and the presence or absence of a clay liner. The paper finally illustrates the economic benefits of sound closure and postclosure care by comparing estimated costs of corrective action to estimated costs of closure and postclosure care at MSWLFs.