Toxicity of road salt to Nova Scotia amphibians

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC₅₀) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species.     

A simple chemical free arsenic removal method for community water supply - A case study from West Bengal, India

This report describes a simple chemical free method that was successfully used by a team of European and Indian scientists (www.qub.ac.uk/tipot) to remove arsenic (As) from groundwater in a village in West Bengal, India. Six such plants are now in operation and are being used to supply water to the local population (www.insituarsenic.org). The study was conducted in Kasimpore, a village in North 24 Parganas District, approximately 25 km from Kolkata. In all cases, total As in treated water was less than the WHO guideline value of 10 μg L⁻¹. The plant produces no sludge and the operation cost is 1.0 US$ per day for producing 2000 L of potable water.     

A Template for Integrated Community Sustainability Planning

This article describes a template for implementing an integrated community sustainability plan. The template emphasizes community engagement and outlines the components of a basic framework for integrating ecological, social and economic dynamics into a community plan. The framework is a series of steps that support a sustainable community development process. While it reflects the Canadian experience, the tools and techniques have applied value for a range of environmental planning contexts around the world. The research is case study based and draws from a diverse range of communities representing many types of infrastructure, demographics and ecological and geographical contexts. A critical path for moving local governments to sustainable community development is the creation and implementation of integrated planning approaches. To be effective and to be implemented, a requisite shift to sustainability requires active community engagement processes, political will, and a commitment to political and administrative accountability, and measurement.     

Contributions of fermentative acidogenic bacteria and sulfate-reducing bacteria to lactate degradation and sulfate reduction

The roles of fermentative acidogenic bacteria and sulfate-reducing bacteria (SRB) in lactate degradation and sulfate reduction in a sulfidogenic bioreactor were investigated by traditional chemical monitoring and culture-independent methods. A continuously stirred tank reactor fed with synthetic wastewater containing lactate and SO(2-)(4) at 35 degrees C, 10h of hydraulic retention time was used. The results showed that sulfate removal efficiency reached 99%, and sulfide and acetate were the main end products after 20 d of operation. 16S rRNA gene based clone libraries and single-strand conformation polymorphism profiles demonstrated that the proportion of SRB increased from 16% to 95%, and that Desulfobulbus spp., Desulfovibrio spp., Pseudomonas spp. and Clostridium spp. formed a stable, dominant community structure. The decreasing COD/SO(2-)(4) ratio had little effect on the community pattern except that Pseudomonas spp. and Desulfobulbus spp. increased slightly. The addition of molybdate to the influent significantly changed the microbial community, sulfate removal efficiency and the pattern of end products. Clostridium spp., Bacteroides spp. and Ruminococcus spp. became the dominant community members. The main end products switched from acetate to ethanol and then to propionate with the oxidation-reduction potentials increasing from -420 to -290 mV. A lactate degradation pathway was deduced: lactate served as the electronic donor for Desulfovibrio spp., or was fermented by Clostridium spp. and Bacteroides spp. to produce propionate or ethanol, which were subsequently utilized by Desulfobulbus spp. and Desulfovibrio spp. The acidotrophic SRB oxidized part of the acetate finally.     

Short term exposure to elevated trinitrotoluene concentrations induced structural and functional changes in the soil bacterial community

We investigated the acute impact of trinitrotoluene (TNT) contamination of soil on the aerobic bacterial community composition and function. The contamination of the environment with explosive residues presents a serious problem at sites across the world, with the highly toxic compound TNT being the most widespread explosive contaminant. We investigated the acute impact of trinitrotoluene (TNT) contamination of soil on the aerobic bacterial community composition and function. Soil microcosms were amended with a range of concentrations of TNT for 30 days. A polyphasic approach encompassing culture-independent molecular analysis by DGGE, community-level physiological profiling (CLPP) and cell enumeration revealed that the amendment of soils with TNT resulted in a shift from slower growing k-strategists towards faster growing r-strategists. Pseudomonads became prevalent at high concentrations of TNT. Pollution induced community tolerance (PICT) was observed as TNT concentrations increased. Chemical analyses revealed that TNT was reduced to its amino derivatives, products of reductive microbial transformation. The transformation to amino derivatives decreased at high concentrations of TNT, indicative of inhibition of microbial TNT transformation.     

四川中东部地区2009年大气硫沉降模拟

采用第三代公共多尺度空气质量模型Models-3/CMAQ,对四川中东部地区2009年1月、4月、7月和10月SO₂排放所产生的硫沉降分布进行数值模拟研究,并且将该模型输出的ρ(SO₂)、SO₄2-湿沉降量分别与地面层的ρ(SO₂)、降水中SO₄2-湿沉降量实测值进行相关分析,探讨硫沉降的季节、区域分布特征及湿沉降变化. 结果表明:ρ(SO₂)模拟值与实测值的R(相关系数)为0.445,SO₄2-湿沉降量模拟值与实测值的R为0.510;四川中东部地区夏季硫沉降量为2.2×104 t,高于其他三季,冬季最小,为1.0×104 t;硫沉降呈三大片区分布,宜宾、乐山、泸州为高值分布区,资阳、遂宁、南充、广安和达州均属于硫沉降低值区,成都、德阳、绵阳片区属硫沉降次高值区;干沉降中SO₂沉降量在各季所占比例均在85%以上,湿沉降中各季SO₄2-沉降量所占比例均在99%以上.      

Optimizing investment strategies for mangrove plantations by considering biological and economic parameters

Coastal deforestation in the Ayeyarwady Delta, Myanmar (formerly Burma) is addressed through the promotion of native-species mangrove plantations on cleared land formerly sustaining natural mangrove forests. To date there are no attempts to determine the optimal mangrove plantation strategy to maximize economic returns for private or communal plantation owners. We integrated empirical biological and economic data to suggest optimal mangrove plantation strategies in the region. We censused 4-yr oldAvicennia officinalis mangrove plantations in two townships to calculate survival and growth rates of mangroves planted using different techniques across an inundation gradient. We used the calculated rates to forecast the production of fuelwood, poles and posts at 10, 13 and 15 yr after establishment. We calculated the compound rate of growth for the three commodities over a 7-yr period, and then forecast commodity price for the same harvest intervals. Integration of those parameters in our model led us to conclude that both profit and the internal rate of return would be greatest for plantations of seedlings raised in polyethylene bags as opposed to bare-root or direct propagule planting. Therefore, the use of potted seedlings should be promoted, despite higher initial costs. The optimal rotation period varies according to ground level and planting technique. Optimizing economic returns for coastal plantations does not necessarily require a sacrifice of ecological benefits. Due to a discrepancy between official conversion quotes and local real value no conversion estimate in USD is given.     

Optimizing investment strategies for mangrove plantations by considering biological and economic parameters

Coastal deforestation in the Ayeyarwady Delta, Myanmar (formerly Burma) is addressed through the promotion of native-species mangrove plantations on cleared land formerly sustaining natural mangrove forests. To date there are no attempts to determine the optimal mangrove plantation strategy to maximize economic returns for private or communal plantation owners. We integrated empirical biological and economic data to suggest optimal mangrove plantation strategies in the region. We censused 4-yr oldAvicennia officinalis mangrove plantations in two townships to calculate survival and growth rates of mangroves planted using different techniques across an inundation gradient. We used the calculated rates to forecast the production of fuelwood, poles and posts at 10, 13 and 15 yr after establishment. We calculated the compound rate of growth for the three commodities over a 7-yr period, and then forecast commodity price for the same harvestintervals. Integration of those parameters in our model led us to conclude that both profit and the internal rate of return would be greatest for plantations of seedlings raised in polyethylene bags as opposed to bare-root or direct propagule planting. Therefore, the use of potted seedlings should be promoted, despite higher initial costs. The optimal rotation period varies according to ground level and planting technique. Optimizing economic returns for coastal plantations does not necessarily require a sacrifice of ecological benefits. Due to a discrepancy between official conversion quotes and local real value no conversion estimate in USD is given.     

Management priorities for Magdalena Bay, Baja California, Mexico

The current lack of a working resource management plan Magdalena Bay (southern Baja California, Mexico) has weakened attempts to set priorities among resource users and has contributed to: reduced fish stocks, land and marine contamination, and declines in the ecological integrity of the bay of 170 000 ha and its vast mangrove lagoon systems. The government agencies responsible for maintaining ecological integrity and managing marine resource use have not been successful in addressing these problems due to jurisdictional ambiguities, lack of community support, and lack of manpower for monitoring and enforcing policies. A framework was designed by the authors to work toward an approach for balancing between community development and conserving ecological integrity at the local level in the peripheral and central zones of the Magdalena Bay system. The goal of this framework was to suggest a basis for setting management priorities that included the perceptions and preferences of stakeholder groups with regard to direct threats to the environmental health of the study areas. To achieve this goal a crossdisciplinary study of the central and peripheral zones was used to examine factors that influence current resource use and the environmental state in these two regions of the bay system. Insights into the preferences and perceptions of stakeholder groups with regard to management priorities were acquired using the key informant technique. The results revealed potential conflicts with regard to preferred management priorities between stakeholder groups, as well as polarities within stakeholder groups themselves.     

Structural and functional variations of phytoplankton communities in the face of multiple disturbances

The global decline of freshwater biodiversity caused by climate change and human activities are supposed to disrupt ecosystem services related to water quality and alter the structure and function of aquatic communities across space and time, yet the effects of the combination of these factors on plankton community ecosystem has received relatively little attention. This study aimed to explore the impacts of disturbances (e.g. human activity, temperature, precipitation, and water level) on phytoplankton community structure (i.e. community evenness and community composition) and function (i.e. resource use efficiency) in four subtropical reservoirs over 7 years from 2010 to 2016. Our results showed that community turnover (measured as community dissimilarity) was positively related to disturbance frequency, but no significant correlation was found between phytoplankton biodiversity (i.e. evenness) and disturbance frequency. Phytoplankton resource use efficiency (RUE = phytoplankton biomass/ total phosphorus) was increased with a higher frequency of disturbance with an exception of cyanobacteria. The RUE of Cyanobacteria and diatoms showed significantly negative correlations with their community evenness, while the RUE of Chlorophyta exhibited a positive correlation with their community turnover. We suggest that multiple environmental disturbances may play crucial roles in shaping the structure and functioning of plankton communities in subtropical reservoirs, and mechanism of this process can provide key information for freshwater uses, management and conservation.