REGION,LANDSCAPE, AND SCALE EFFECTS ON LAKE SUPERIOR TRIBUTARY WATER QUALITY1

ABSTRACT: In 1998 and 1999, third‐order watersheds in high mature forest (HMF) and low mature forest (LMF) classes were selected along gradients of watershed storage within each of two hydrogeomorphic regions in the Lake Superior Basin to evaluate threshold effects of storage on hydrologic regimes and watershed exports. Differences were detected between regions (North and South Shore) for particulates, nutrients, and pH, with all but silica values higher for South Shore streams (p < 0.05). Mature forest effects were detected for turbidity, nutrients, color, and alkalinity, with higher values in the LMF watersheds, that is, watersheds with less that 50 percent mature forest cover. Dissolved N, ammonium, N:P, organic carbon, and color increased, while suspended solids, turbidity, and dissolved P decreased as a function of storage. Few two‐way interactions were detected between region and mature forest or watershed storage, thus threshold based classification schemes could be used to extrapolate effects across regions. Both regional differences in water quality and those associated with watershed attributes were more common for third‐order streams in the western Lake Superior drainage basin as compared with second‐order streams examined in an earlier study. Use of ecoregions alone as a basis for setting regional water quality criteria would have led to misinterpretation of reference condition and assessment of impacts in the Northern Lakes and Forest Ecoregion.     

The effectiveness of the e-money incentive mechanism in promoting separation of recyclables at source in Malaysia

Journal of Material Cycles and Waste Management - A new concept of a reward system by two e-money-incentive systems aimed at improving separation at source toward reducing residual waste generation...     

Effective communication about complex environmental issues: Perceived quality of information about carbon dioxide capture and storage (CCS) depends on stakeholder collaboration

This experimental research addresses the effectiveness of communication about complex environmental issues, depending on whether the same information is provided by multiple collaborating or by individual organizations (i.e., stakeholders). The information provided pertains to carbon dioxide capture and storage (CCS) technology, as an example of a complex environmental issue. In Studies 1 (N = 75) and 2 (N = 66) we found that participants perceived factual information from collaborating stakeholders to be of higher quality than when the same information was provided by individual stakeholders. As predicted, the expectation of diverse perspectives being represented in the collaborative information mediated this effect. In addition, in Study 3 (N = 79) the perceived dissimilarity of collaborating stakeholders was shown to be an important precondition for the collaboration effect observed in Studies 1 and 2. Finally, these studies indicate that occasional collaboration between different stakeholders does not necessarily harm the perceived credibility of each individual stakeholder.     

Impact of gamma irradiation on the transformation efficiency for extracellular plasmid DNA

Extracellular DNA is omnipresent in aquatic environments and is thought to be a genetic material for horizontal gene transformation between microorganisms. We studied the impact of gamma irradiation on the transformation efficiency (transformants number per ng of DNA per ml) of extracellular DNA. Plasmid pEGFP as a model extracellular DNA was irradiated by gamma rays. The transformation efficiency decreased with the increase in radiation dose. A total dose of 10Gy is normally not lethal for microorganisms but certainly affects the transformation efficiency of extracellular DNA. The decrease in the efficiency would be induced by strand breaks of extracellular DNA because the yield of both single-strand breaks (SSBs) and double-strand breaks (DSBs) increased with the increase in radiation dose. The relative transformation efficiency of SSBs and DSBs to that of covalently closed circles (CCCs) was 30.3% and 0.2%, respectively. This impact on natural transformation suggests an inability of microorganisms to acquire new characteristics which should be normally acquired.     

Effects of acute γ-irradiation on the aquatic microbial microcosm in comparison with chemicals

Effects of acute γ-irradiation were investigated in the aquatic microcosm consisting of green algae (Chlorella sp. and Scenedesmus sp.) and a blue–green alga (Tolypothrix sp.) as producers; an oligochaete (Aeolosoma hemprichi), rotifers (Lecane sp. and Philodina sp.) and a ciliate protozoan (Cyclidium glaucoma) as consumers; and more than four species of bacteria as decomposers. At 100 Gy, populations were not affected in any taxa. At 500–5000 Gy, one or three taxa died out and populations of two or three taxa decreased over time, while that of Tolypothrix sp. increased. This Tolypothrix sp. increase was likely an indirect effect due to interspecies interactions. The principal response curve analysis revealed that the main trend of the effects was a dose-dependent population decrease. For a better understanding of radiation risks in aquatic microbial communities, effect doses of γ-rays compared with copper, herbicides and detergents were evaluated using the radiochemoecological conceptual model and the effect index for microcosm.     

How organizational motives and communications affect public trust in organizations: The case of carbon dioxide capture and storage

Preventing climate change is among the greatest environmental challenges facing the world today. Recently developed carbon dioxide capture and storage (CCS) technology is an important strategy to mitigate climate change. Public trust in organizations involved in CCS technology is important for successful implementation of this technology. This work adresses how inferred organizational motives and organizational communications affect public trust in these organizations. Study 1 (N = 264) showed that Dutch citizens generally have less trust in the industrial organizations than in the environmental NGOs involved in CCS. As predicted, inferred organizational motives (organization-serving motives versus public-serving motives) accounted for this difference. In Study 2 (N = 78) and Study 3 (N = 51) we used experimental designs. Both experiments showed that organizations that communicated arguments incongruent with inferred organizational motives instigated less trust than organizations that communicated arguments congruent with inferred organizational motives. Study 3 additionally showed that communicating an incongruent and a congruent argument together diminished the negative effects of the incongruent argument. In both Study 2 and Study 3 the effect of congruency on trust was mediated by perceived honesty of the organizations.     

Isolation of a fungus from denitrifying activated sludge that degrades highly chlorinated dioxins

 This article reports the potential of denitrifying activated sludge to degrade highly chlorinated dioxins, especially from a (landfill) leacheate treatment plant in Japan, and the isolation from this denitrifying activated sludge of a microorganism able to degrade highly chlorinated dioxins. Using a 700-ml bioreactor, denitrifying activated sludge was cultivated under denitrifying conditions by adding 2.0 ng of a mixture of 4- to 8-chlorinated dioxins from fly ash. The dioxin contents of the sample, effluent, and medium before and after cultivation were measured by gas chromatography–mass spectrometry (GC–MS). After 7 days cultivation, about 90% of added dioxins were lost (average percentage of isomer depletion). A dioxin-degrading microorganism was isolated from the activated sludge. Lignin was added to the medium as a color indicator of aromatic compound degradation, and the lignin-decolorizing microorganisms in the denitrifying activated sludge were screened. Some strains were isolated, and one major isolated fungus, strain 622, decolorized lignin effectively. Strain 622 was identified as an Acremonium sp. from its morphological characteristics. It could decolorize lignin by 24% under paraffin-sealed anaerobic conditions. After the cultivation of strain 622 with a 2 ng/ml mixture of 4- to 8-chlorinated dioxins for 1 day, 82% (average for individual isomers) of the added 4- to 8-chlorinated dioxins had been degraded. Added octachlorodibenzo-p-dioxin (OCDD, 100 ng) was degraded under aerobic conditions after 8 h of incubation. During this process, heptachlorodibenzo-p-dioxin was produced and appeared to be a degradation product of OCDD. 1- or 2-hydroxydibenzo-p-dioxin from OCDD was also identified as the degradation product by GC–MS. These results indicated that OCDD was degraded to the nonchlorinated dibenzo-p-dioxins through dechlorination by Acremonium sp. strain 622. Received: October 12, 2001 / Accepted: March 11, 2002