An ecological approach to environmental impact assessment

Carbon cycling analysis is presented as a means for assessing anthropogenic perturbations in an ecosystem. Data from oligotrophic, eutrophic, and dystrophic (bog) lakes are used to show general trends in the lacustrine carbon cycle. The oligotrophic lake is an unstressed system and the eutrophic lake is under nutrient enrichment with high algal standing crops and productivity. The bog lake is a pH-stressed environment that is primarily a grazing ecosystem. It is hoped that a more effective environmental impact assessment will result from the use of carbon cycling as a unifying concept in ecosystem analysis.     

Ecological restoration as a strategy for conserving biological diversity

Though the restoration of disturbed ecosystems has so far played a relatively modest role in the effort to conserve biological diversity, there are reasons to suspect that its role will increase and that its contribution to the maintenance of diversity will ultimately prove crucial as techniques are further refined and as pristine areas for preservation become scarcer and more expensive.It is now possible to restore a number of North American communities with some confidence. However, it should be noted that many current efforts to return degraded lands to productive use, like attempts to reclaim land disturbed by mining, try only for rehabilitation to a socially acceptable condition and fall considerably short of actually restoring a native ecological community.Possible uses for restoration in the conservation of biodiversity include not only the creation of habitat on derelict sites, but also techniques for enlarging and redesigning existing reserves. Restoration may even make it possible to move reserves entirely in response to long-term events, such as changes in climate. Restoration in the form of reintroduction of single species to preexisting or restored habitat is also a critical link in programs to conserve species ex situ in the expectation of eventually returning them to the wild. And restoration provides opportunities to increase diversity through activities as diverse as management of utility corridors, transportation rights-of-way, and parks.     

Evaluating the sampling pattern when detecting Zones of Abrupt Change

We present a method for detecting the zones where an irregularly sampled variable changes abruptly in the plane. Such zones are called Zones of Abrupt Change (ZACs). This method not only allows estimation of ZACs, but also testing of their statistical significance against the null hypothesis of a stationary correlated random field. The sampling pattern, in particular its local density, is crucial in the detection of potential ZACs. In this paper, we address the problem of evaluating the sampling pattern by assessing the power of the local test used for detecting ZACs. It is shown that mapping the power allows us to identify zones where ZACs may or may not be detected. The methodology is applied to a soil data set sampled at eight different dates in an agricultural field. Detecting ZACs for the soil water content allowed us to identify permanent structures in the agricultural field related to the boundaries between different soil types. Mapping the power for various sampling densities proved to be useful to determine the minimal sampling density necessary for detecting ZACs.

Green chemistry with process intensification for sustainable biodiesel production

Biodiesel as a renewable fuel has the potential to replace non-renewable fossil fuels and associated environmental pollution. The most commonly used method in biodiesel production is transesterification of virgin and used oil feedstock. However, the chemical reaction (transesterification) does not proceed spontaneously, which means excess reactants are required to move the reaction to completion. The biodiesel reaction efficiency can be improved by incorporating green chemistry principles and process intensification effects. Green chemistry principles can be used to design chemical products and processes that reduce or eliminate the use and generation of hazardous substances. Microwave- and ultrasound-enhanced biodiesel synthesis can improve the reaction efficiency due to higher product recovery, low by-product formation, and reduced energy consumption. In addition, utilization of green metrics such as E-factor, atom economy (utilization), mass intensity or mass productivity, and reaction mass efficiency can help design safer and highly efficient biodiesel synthesis. Green chemistry principles have been analyzed for other processes in greater details, but they are rarely discussed in the context of biodiesel production. Process intensification by microwave- and ultrasound-mediated biodiesel production was never discussed from the perspective of green chemistry and sustainable process development. This research review article discusses the role of green chemistry and process intensification in biodiesel production followed by specific examples and illustrations on green metrics of microwave- and ultrasound-enhanced biodiesel synthesis and the effect of catalysts and solvents including discussions on reaction kinetics and activation energy in detail for the first time in the literature.