Energy efficiency and conservation for individual Americans

Americans make up only 4% of the world population, yet currently consume 25% of the world’s fossil fuels. The U.S. imports 63% of its oil and it is predicted that by 2020 the U.S. will be importing 95% of its oil resources. Over the past century, ample and affordable supplies of fossil fuels have powered the growth and prosperity of the economies of the US and other countries. Within this century, world oil supplies will decline while demand is projected to continue to increase, suggesting that we will have to transition to different fuels or become much more energy efficient or both. Looking ahead to the near decades, estimates are that consumers will have to reduce their energy use by at least 50%. This reduction will be necessary in large part due the decline in the availability of conventional oil and gas, but also because the U.S. population will continue to grow in number. Although government action is important, individuals too often discount their ability to make significant contributions to solving such major problems. This investigation identifies how informed and concerned individuals can collectively conserve fossil energy. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. An erratum to this article can be found at     

The extraction and utilization of local and scientific geospatial knowledge within the Bluff oyster fishery, New Zealand

This paper assesses the Bluff oyster fishery in New Zealand as a case study in common pool resource management. It discusses ways in which modern information technology, augmented by low-tech data gathering strategies and community ethnography, can be used to produce an integrated scientific and local knowledge-inspired fishery database that lends itself to fostering collaboration in resource management and planning. The specific context and state of the oyster fishery in Bluff are described. Issues regarding undocumented and ephemeral intergenerational knowledge, much of which is geospatial in nature, on the fishery, the current crisis that many see in the future of the fishery, and a lack of cohesion or common sense of purpose between the stakeholder groups are discussed. It is argued that the digital resource that results from the integration of local and scientific knowledge and the potential community building processes that can ensue from collaboration and dialogue around this centrepiece are of central importance in developing an oyster fishery management plan that is holistic in concept and sustainable in purpose.     

Australian approaches to coastal vulnerability assessment

The Australian coastline is one of the longest and most diverse of any in the world, and Australian researchers have developed preliminary models of the behaviour of major coastal systems such as beaches and reefs. The Australian population is particularly focused along the coastline, especially in metropolitan centres; however, the population of regional centres along the coast is increasing steadily in response to a phenomenon termed seachange. Coastal systems are increasingly threatened by potential impacts as a result of climate change, as indicated by the successive assessments by the Intergovernmental Panel on Climate Change (IPCC). Although Australia played a central role in applying a common methodology (CM), developed from IPCC guidelines in the 1990s, and in devising alternative approaches, which were initially trialled at nine sites on the Australian coast, there has not been a nationally co-ordinated approach to assessing the coastal vulnerability of Australia, and such an approach is only emerging now. Instead, there have been a series of different approaches adopted to look at the different parts of the Australian coast, including wetland mapping in northern Australia; geomorphic unit mapping in South Australia; storm surge vulnerability modelling in Queensland; probabilistic approaches to beach erosion in New South Wales; indicative mapping of potential coastal retreat in Tasmania. Additionally, there have been methods proposed by insurers and coastal engineers to meet their requirements. Since 2005, the Australian government has once again seen the need for a national coastal vulnerability assessment, and a series of studies are planned or under way to achieve the aims of a National Climate Change Adaptation Framework.     

Effect of physico-chemical pretreatment on the removal efficiency of horizontal subsurface-flow constructed wetlands

In this study, we tested the effect of a physico-chemical pretreatment on contaminant removal efficiency in two experimental horizontal subsurface-flow constructed wetlands (SSF CWs). One SSF CW was fed with settled urban wastewater, whereas the other with the same wastewater after it had undergone a physico-chemical pretreatment. The SSF CWs were operated with three different hydraulic retention times. During the experiments the effluent concentrations of COD, ammonia N and sulfate were very similar, and, therefore, the physico-chemical pretreatment did not improve the quality of the effluents. COD removal efficiency (as percentage or mass surface removal rate) was slightly greater in the SSF CW fed with pretreated wastewater. Ammonia N removal efficiency was, in general, similar in both SSF CWs and very high (80-90%). At the end of the experiments it was observed that in the SSF CW fed with settled wastewater the hydraulic conductivity decreased by a 20%.     

The role of humic non-exchangeable binding in the promotion of metal ion transport in groundwaters in the environment

Metal ions form strong complexes with humic substances. When the metal ion is first complexed by humic material, it is bound in an 'exchangeable' mode. The metal ion in this fraction is strongly bound, however, if the metal-humic complex encounters a stronger binding site on a surface, then the metal ion may dissociate from the humic substance and be immobilised. However, over time, exchangeably-bound metal may transfer to a 'non-exchangeable' mode. Transfer into this mode and dissociation from it are slow, regardless of the strength of the competing sink, and so immobilisation may be hindered. A series of coupled chemical transport calculations has been performed to investigate the likely effects of non-exchangeable binding upon the transport of metal ions in the environment. The calculations show that metal in the non-exchangeable mode will have a significantly higher mobility than that in the exchangeable mode. The critical factor is the ratio of the non-exchangeable first-order dissociation rate constant and the residence time in the groundwater column, metal ion mobility increasing with decreasing rate constant. A second series of calculations has investigated the effect of the sorption to surfaces of humic/metal complexes on the transport of the non-exchangeably bound metal. It was found that such sorption may reduce mobility, depending upon the humic fraction to which the metal ion is bound. For the more weakly sorbing humic fractions, under ambient conditions (humic concentration etc.) the non-exchangeable fraction may still transport significantly. However, for the more strongly sorbed fractions, the non-exchangeable fraction has little effect upon mobility. In addition to direct retardation, sorption also increases the residence time of the non-exchangeable fraction, giving more time for dissociation and immobilisation. The non-exchangeable dissociation reaction, and the sorption reaction have been classified in terms of two Damkohler numbers, which can be used to determine the importance of chemical kinetics during transport calculations. These numbers have been used to develop a set of rules that determine when full chemical kinetic calculations are required for a reliable prediction, and when equilibrium may be assumed, or when the reactions are sufficiently slow that they may be ignored completely.     

The acetochlor registration partnership: prospective ground water monitoring program

The Acetochlor Registration Partnership conducted a prospective ground water (PGW) monitoring program to investigate acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] transport to ground water at eight sites. The distribution of soil textures among these sites was weighted toward coarser soil types, while also including finer-textured soils that dominate most corn (Zea mays L.)-growing areas of the United States. Each site consisted of a 1.2-ha test plot adjacent to a 0.2-ha control plot. Suction lysimeters and monitoring wells were installed at multiple depths within each test and control plot to sample soil-pore water and near-surface ground water. Irrigation was applied to each site during the growing season to ensure water input of 110 to 200% of average historical rainfall. Acetochlor dissipated rapidly from surface soils at all sites with a DT(50) (time for 50% of the initial residues to dissipate) of only 3 to 9 d, but leaching was not an important loss mechanism, with only 0.25% of the 15,312 soil-pore water and ground water samples analyzed containing parent acetochlor at or above 0.05 microg L(-1). However, quantifiable residues of a soil degradation product, acetochlor ethanesulfonic acid, were more common, with approximately 16% of water samples containing concentrations at or above 1.0 microg L(-1). A second soil degradation product, acetochlor oxanilic acid, was present at concentrations at or above 1.0 microg L(-1) in only 0.15% of water samples analyzed. The acetochlor PGW program demonstrated that acetochlor lacks the potential to leach to ground water at detectable concentrations, and when applied in accordance with label restrictions, is unlikely to move to ground water at concentrations hazardous to human health.     

Regional coexistence and local dominance in Chaoborus: species sorting along a predation gradient

Variation in the intensity of predation across the well-known environmental gradient of freshwater habitats from small, ephemeral ponds to large, permanent lakes is a key factor in the development and maintenance of aquatic community structure. Here, we present data on the distribution and abundance of four species of Chaoborus (Diptera: Chaoboridae) across this environmental gradient. Chaoborus show a distinct pattern of species sorting when aquatic systems are divided into fish and fishless environments, and this pattern is consistent with species traits known to influence their vulnerability to fish predation (i.e., pigmentation, diel vertical migration [DVM] behavior, and body size). To test whether fish are the drivers of this pattern, we created a gradient in fish density by stocking bluegill sunfish (Lepomis macrochirus) into 15 experimental ponds in southwestern Michigan, USA, and then allowed Chaoborus species to colonize. There was clear evidence of species sorting along the predation gradient; Chaoborus americanus was most abundant in the fishless ponds, C. flavicans was neutral in response to fish, and C. punctipennis and C. albatus were most abundant at high fish biomass, a response consistent with their field pattern. Furthermore, prey preference experiments confirm that size selective predation and differences in Chaoborus species traits contribute to the pattern of Chaoborus abundance and distribution.