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为考察三峡库区澎溪河营养盐的时空分布特征及营养状态,于2013~2014年对澎溪河不同断面透明度、高锰酸盐指数以及总氮、氨氮、总磷、叶绿素a的含量进行取样调查,对营养盐的时空变化特征进行分析,结合相关性分析,利用单因子法和综合营养状态指数法评价水体营养盐结构和营养状态。结果发现,澎溪河营养盐具有明显的季节差异性和空间分布差异性。相关性分析表明澎溪河上游河段叶绿素a含量与透明度、高锰酸盐指数、总氮含量、总磷含量的线性相关性不显著,而中段高阳渡口叶绿素a含量与总磷含量呈极显著正相关。单因子法评价结果显示,澎溪河水质为Ⅱ~Ⅲ类。水体综合营养状态指标范围为56~135,处于富营养至重度富营养化状态之间;春季3~5月及秋季10月,部分断面富营养化状态极高。 相似文献
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根据2006~2017年水质监测数据资料,对升钟水库水质和营养化状态变化进行分析,探讨了水库水质演变规律、富营养化发展趋势及主要影响因子,同时利用线性回归模型和累积概率密度模型对升钟水库富营养化未来5年的发展趋势进行风险预测。结果表明:升钟水库水质呈上升趋势,水质状态为Ⅱ类。综合营养状态指数显示水库营养状态由富营养逐步向中营养转变,水体中的总氮、总磷、高锰酸盐指数呈显著下降趋势,分析表明总磷是升钟湖富营养化的关键限制因子,未来5年内升钟水库的大坝断面有富营养化的中度风险(58.78%)。为控制环境风险,针对性提出防治升钟水库富营养化的对策和建议。 相似文献
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为了探究紫坪铺水库水质情况和富营养化状态变化情况,于2012年1月至2016年12月每月对水库四个监测点位进行采样分析,基于《地表水环境质量标准》(GB3838—2002)水质评价、综合营养状态指数(TLI)等方法,分析水质情况和水体富营养化的时间和空间变化情况。结果表明:①年平均水质指标中:溶解氧、高锰酸盐指数、五日生化需氧量、氨氮主要为Ⅰ类、Ⅱ类水质,总氮为Ⅲ类水质,总磷除2016年为Ⅳ类水质外其余年份均为Ⅲ类水质;②TLI年均值主要呈逐年升高趋势,但最高值为29.63;③TLI值空间分布特征为:库头﹥入湖库口﹥库中﹥库尾,时间分布特征为:5月、6月、7月、8月﹥1月、2月、3月、4月、9月﹥10月、11月、12月(丰水期﹥平水期﹥枯水期)。研究显示,紫坪铺水库水质整体主要处于湖库地表水Ⅲ类水质和贫营养化状态。 相似文献
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《中国环境管理干部学院学报》2017,(4)
为了判断陡河水体的营养状态,为水体修复提供理论基础,采用浮游生物定量方法对陡河水库水体中浮游植物群种类、数量进行分析,研究不同环境条件下水体中浮游植物的优势种群及变化规律。结果表明:浮游植物共有7个门,45种以上,是绿藻+硅藻型的群落结构类型,并有比较稳定的隐藻、金藻和蓝藻种类,浮游植物的细胞密度在100万个/L以上。综合来看,陡河水库水体处于轻度富营养状态。 相似文献
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南充市嘉陵江干流高锰酸盐指数和氨氮动态变化及影响因素 总被引:1,自引:0,他引:1
《四川环境》2018,(6)
为更好地掌握南充市嘉陵江干流主要污染物质的情况,使用2011~2015年南充市嘉陵江干流3个主要断面的监测数据,采用Pearson相关性分析、单因子水质标识指数等方法进行分析和探讨了氨氮、高锰酸盐指数的动态趋势及引起变化的因素。结果显示:五年来,3个监测点的DO和p H达到Ⅲ类标准,且变化基本稳定。南充段嘉陵江干流沙溪站(入境断面)有机污染物质在逐年减少,进入南充境内清泉寺站(控制断面)受到了轻微的污染,出境断面烈面站的受轻度污染程度均高于其余两个断面。丰水期和平水期,高锰酸盐指数增大,而氨氮含量呈下降趋势;枯水期两项指标增减趋势相同。五年中3个自动监测站的高锰酸盐指数和氨氮监测数据均达到Ⅲ类水质标准内,其中沙溪监测点水质最好。2011~2015年南充段嘉陵江水质状况整体保持良好,但烈面(出境)的两项指标有上升趋势,应加强对清泉寺水源地的防护,进一步加强对出境断面的污染治理。 相似文献
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A. U. Mallik 《Environmental management》1995,19(5):675-684
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into
heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil
acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed
habitats.
If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged
unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest
vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation
shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation. 相似文献
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Pickett ST Cadenasso ML Grove JM Boone CG Groffman PM Irwin E Kaushal SS Marshall V McGrath BP Nilon CH Pouyat RV Szlavecz K Troy A Warren P 《Journal of environmental management》2011,92(3):331-362
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs. 相似文献
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Justin D. Burdine 《Local Environment》2018,23(2):198-219
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered. 相似文献
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Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States 总被引:2,自引:0,他引:2
Christopher Carrier Ajay Kalra Sajjad Ahmad 《Journal of the American Water Resources Association》2013,49(6):1351-1366
In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management. 相似文献
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Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions. 相似文献
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Donald L. Chery Calvin G. Clyde Roger E. Smith 《Journal of the American Water Resources Association》1979,15(4):1126-1145
ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m2) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft3/sec (0.085 to 3.34 m3/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes. 相似文献
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Calvin P. C. Poon Frank J. DeLuise 《Journal of the American Water Resources Association》1967,3(4):26-35
Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality. 相似文献
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Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source. 相似文献
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Sources and Transport of Phosphorus to Rivers in California and Adjacent States,U.S., as Determined by SPARROW Modeling
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Joseph Domagalski Dina Saleh 《Journal of the American Water Resources Association》2015,51(6):1463-1486
The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams. 相似文献
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Darryl Macer 《Journal of Agricultural and Environmental Ethics》1997,10(3):249-267
The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that
we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals,
and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships
between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy
and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia
and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan,
New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there
were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand.
Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness
to be, and whether this relates to human ethics of the relationships.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献