Soil erosion and sediment fluxes analysis: a watershed study of the Ni Reservoir,Spotsylvania County,VA, USA

Anthropogenic forces that alter the physical landscape are known to cause significant soil erosion, which has negative impact on surface water bodies, such as rivers, lakes/reservoirs, and coastal zones, and thus sediment control has become one of the central aspects of catchment management planning. The revised universal soil loss equation empirical model, erosion pins, and isotopic sediment core analyses were used to evaluate watershed erosion, stream bank erosion, and reservoir sediment accumulation rates for Ni Reservoir, in central Virginia. Land-use and land cover seems to be dominant control in watershed soil erosion, with barren land and human-disturbed areas contributing the most sediment, and forest and herbaceous areas contributing the least. Results show a 7 % increase in human development from 2001 (14 %) to 2009 (21.6 %), corresponding to an increase in soil loss of 0.82 Mg ha^-1 year^-1 in the same time period. ²¹⁰Pb-based sediment accumulation rates at three locations in Ni Reservoir were 1.020, 0.364, and 0.543 g cm^-2 year^-1 respectively, indicating that sediment accumulation and distribution in the reservoir is influenced by reservoir configuration and significant contributions from bedload. All three locations indicate an increase in modern sediment accumulation rates. Erosion pin results show variability in stream bank erosion with values ranging from 4.7 to 11.3 cm year^-1. These results indicate that urban growth and the decline in vegetative cover has increased sediment fluxes from the watershed and poses a significant threat to the long-term sustainability of the Ni Reservoir as urbanization continues to increase.     

Vibrational signals in a gregarious sawfly larva (<Emphasis Type="Italic">Perga affinis</Emphasis>): group coordination or competitive signaling?

Group living confers both benefits and costs to the individuals involved. Benefits may include enhanced defense, thermoregulation, and increased foraging efficiency while costs often involve competition for resources such as food, shelter, and mates. Communication provides a medium of exchange among individuals engaged in either cooperative or competitive interactions. The functional analysis of signals within groups therefore requires testing both cooperative and competitive functions, although the latter is infrequently done. In this paper, I study the use of two vibrational signals in a gregarious, processionary Australian sawfly larva, Perga affinis: tapping and contractions. Tapping involves striking the substrate with the sclerotized portion of the abdominal tail and a contraction is a fast, whole-body twitch, which is both tactile and vibrational in its transmission. For tapping, I first demonstrate that it is a form of communication, as tapping of one larva elicits tapping in another, and that it is transmitted through substrate vibrations. I then test whether the signal is mostly cooperative or competitive in nature by examining it in light of two hypotheses: (1) the Group Coordination hypothesis, stating that the signal functions to maintain group cohesiveness and (2) the Competitive Signaling hypothesis, stating that tapping serves as a competitive assessment signal between larvae while feeding. For contractions, I test only the group coordination hypothesis that they serve to coordinate and initiate group movement. Results support the group coordination hypothesis for each signal. While feeding, lone larvae (without potential competitors) were significantly more likely to tap than those in groups, and this trend continued in non-feeding situations. Contractions regularly preceded periods of group movement during processions and were given with increasing frequency before departure from preforaging clusters. The vibrational signals in this processionary species likely function cooperatively to maintain group cohesiveness and coordinate movement.     

Antibacterial and antimutagenic activitiy of extracts and essential oil from (Tunisian) Pistacia lentiscus

Aqueous and flavonoid-enriched extract as well as essential oil (EO) obtained from leaves of Pistacia lentiscus were assessed for antibacterial and antimutagenic activities. Antibacterial activity of different extracts and EO were evaluated against six bacterial strains. A marked inhibitory effect was observed against Salmonella typhimurium, whereas lower activity was observed against Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enteritidis. EO showed significant inhibitory effects against Salmonella typhimurium, Salmonella enteritidis and Staphylococcus aureus. The antimutagenic activity of the different extracts against Aflatoxin B₁ (AFB₁) and sodium azide was demonstrated with the Salmonella typhymurium assay. The number of revertants per plate decreased significantly when the plant extracts were added to the assay system using Salmonella typhimurium TA100, TA98 and TA1535.     

多效膜蒸馏技术浓缩回收废水中的二甲基亚砜

利用具有内部潜热回收功能的气隙式多效膜蒸馏(MEMD)组件对含二甲基亚砜(DMSO)的化纤废水进行了浓缩回收研究,考察了料液中DMSO浓度、进料流量、进料温度和膜侧进口温度对膜通量、造水比、分离因子和回收率的影响。结果表明,多效膜蒸馏可以将DMSO废水浓缩至200~300 g/L;初始浓度为6.2 g/L时,造水比和分离因子最高值分别为12.4和76.0;虽然膜通量、造水比和分离因子均随料液浓度增大而下降,但是当DMSO浓度达到200 g/L时,膜通量、造水比、分离因子仍分别高达3.74 L/(m2·h)、7.1、32.1;在整个浓缩过程中,回收率维持在99.6%以上;当DMSO废水浓缩达到150 g/L以上时,含有少量DMSO的渗透液可作为二次料液继续用MEMD过程浓缩。膜组件在连续运行的1个月内保持了良好的操作性能。该实验研究表明,多效膜蒸馏过程可以高效节能地浓缩回收化纤废水中的DMSO。     

Risk assessment of heavy metal toxicity of soil irrigated with treated wastewater using heat shock proteins stress responses: case of El Hajeb,Sfax, Tunisia

Heavy metal contamination of soil resulting from treated wastewater irrigation can cause serious concerns resulting from consuming contaminated crops. Therefore, it is crucial to assess hazard related to wastewater reuse. In the present investigation, we suggest the use of biomarker approach as a new tool for risk assessment of wastewater reuse in irrigation as an improvement to the conventional detection of physicochemical accumulation in irrigated sites. A field study was conducted at two major sites irrigated with treated wastewater and comparisons were made with a control site. Different soil depths were considered to investigate the extent of heavy metal leaching, the estrogenic activity, and the biomarker response. Results have shown that a longer irrigation period (20 years) caused a slight decrease in soil metal levels when compared to the soil irrigated for 12 years. The highest levels of Cr, Co, Ni, Pb, and Zn were detected at 20 and 40 cm horizons in plots irrigated with wastewater for 12 years. The latter finding could be attributed to chemical leaching to deeper plots for longer irrigation period. Furthermore, the treated wastewater sample showed a high estrogenic activity while none of the soil samples could induce any estrogenic activity. Regarding the stress response, it was observed that the highest stress shown by the HSP47 promoter transfected cells was induced by a longer irrigation period. Finally, the treated wastewater and the irrigated soils exhibited an overexpression of HSP60 in comparison with reference soil following 1 h exposure. In conclusion, in vitro techniques can be efficiently used to assess potential hazard related to wastewater reuse.     

台北市生活垃圾管理经验及启示

台北市生活垃圾管理效果显著,人均生活垃圾日清运量年均减量7.3%、资源回收率年均增长28.3%并带动资源回收产业发展、居民负担仅为1998年的22.0%、社会成本较1998年减少30.7%。主要经验包括:明确的生活垃圾减量与资源回收目标;系统的管理模式设计,包括政府(环保局、地方清洁队、资源回收管理基金)、生产商、回收商、处理商、居民、垃圾焚烧厂和填埋场以及第三方等主要干系人。采取的主要政策手段包括强制源头分类、随袋征收垃圾处理费、建立资源回收管理基金、对资源回收行业的政策扶持以及信息公开与公众参与等。台北市先进的生活垃圾管理经验对中国大陆城市开展垃圾分类与资源化管理具有重要的参考价值。     

Bathymetric variation of epiphytic assemblages on Posidonia oceanica (L.) Delile leaves in relation to anthropogenic disturbance in the southeastern Mediterranean

A survey of the epiphytic leaves of Posidonia oceanica was conducted along a depth transect at both the control station Attaya in the Kerkennah Islands and the disturbed Mahres station on the Sfax coast (Tunisia). Samples were collected by scuba divers at depths of 5, 10, 15, and 20 m in July 2008. We evaluated whether the pattern of spatial variability of the macroepiphyte assemblages of leaves of Posidonia oceanica differed in relation to anthropogenic interference. The results indicate that the decrease in shoot density and leaf length according to depth was low at Mahres. The biomass of epiphytic leaves and the percentage cover of epiphytic assemblages decreased with depth for both stations and heavily at Mahres, this decline being related to anthropogenic disturbance. This study shows that the highest values of epifauna and epiflora were detected at the disturbed station Mahres. Macroalgae assemblages decreased with depth at both stations and were dominated by Rhodophyta, whereas the percentage cover of the epifauna leaf that decreases according to depth was dominated by Hydrozoa and Bryozoa. Changes in epiphyte assemblages, epiphytic biomass, percentage cover, and species richness in proportion to Heterokontophyta, Rhodophyta, Cyanobacteria, Hydrozoa, Porifera, and Tunicata between the two stations constitute promising tools for detecting environmental disturbance.     

Integrating in-situ, Landsat, and MODIS data for mapping in Southern African savannas: experiences of LCCS-based land-cover mapping in the Kalahari in Namibia

Integrated ecosystem assessment initiatives are important steps towards a global biodiversity observing system. Reliable earth observation data are key information for tracking biodiversity change on various scales. Regarding the establishment of standardized environmental observation systems, a key question is: What can be observed on each scale and how can land cover information be transferred? In this study, a land cover map from a dry semi-arid savanna ecosystem in Namibia was obtained based on the UN LCCS, in-situ data, and MODIS and Landsat satellite imagery. In situ botanical relevé samples were used as baseline data for the definition of a standardized LCCS legend. A standard LCCS code for savanna vegetation types is introduced. An object-oriented segmentation of Landsat imagery was used as intermediate stage for downscaling in-situ training data on a coarse MODIS resolution. MODIS time series metrics of the growing season 2004/2005 were used to classify Kalahari vegetation types using a tree-based ensemble classifier (Random Forest). The prevailing Kalahari vegetation types based on LCCS was open broadleaved deciduous shrubland with an herbaceous layer which differs from the class assignments of the global and regional land-cover maps. The separability analysis based on Bhattacharya distance measurements applied on two LCCS levels indicated a relationship of spectral mapping dependencies of annual MODIS time series features due to the thematic detail of the classification scheme. The analysis of LCCS classifiers showed an increased significance of life-form composition and soil conditions to the mapping accuracy. An overall accuracy of 92.48% was achieved. Woody plant associations proved to be most stable due to small omission and commission errors. The case study comprised a first suitability assessment of the LCCS classifier approach for a southern African savanna ecosystem.     

Conservation Covenants on Private Land: Issues with Measuring and Achieving Biodiversity Outcomes in Australia

Conservation covenants and easements have become essential tools to secure biodiversity outcomes on private land, and to assist in meeting international protection targets. In Australia, the number and spatial area of conservation covenants has grown significantly in the past decade. Yet there has been little research or detailed policy analysis of conservation covenanting in Australia. We sought to determine how conservation covenanting agencies were measuring the biodiversity conservation outcomes achieved on covenanted properties, and factors inhibiting or contributing to measuring these outcomes. In addition, we also investigated the drivers and constraints associated with actually delivering the biodiversity outcomes, drawing on detailed input from covenanting programs. Although all conservation covenanting programs had the broad aim of maintaining or improving biodiversity in their covenants in the long term, the specific stated objectives of conservation covenanting programs varied. Programs undertook monitoring and evaluation in different ways and at different spatial and temporal scales. Thus, it was difficult to determine the extent Australian conservation covenanting agencies were measuring the biodiversity conservation outcomes achieved on covenanted properties on a national scale. Lack of time available to covenantors to undertake management was one of the biggest impediments to achieving biodiversity conservation outcomes. A lack of financial resources and human capital to monitor, knowing what to monitor, inconsistent monitoring methodologies, a lack of benchmark data, and length of time to achieve outcomes were all considered potential barriers to monitoring the biodiversity conservation outcomes of conservation covenants.