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71.
In the Ohio River (OR), backwater confluence sedimentation dynamics are understudied, however, these river features are expected to be influential on the system’s ecological and economic function when integrated along the river’s length. In the following paper, we test the efficacy of organic and inorganic tracers for sediment fingerprinting in backwater confluences; we use fingerprinting results to evidence sediment dynamics controlling deposition patterns in confluences used for wetland and marina functions; and we quantify the spatial extent of tributary drainages with wetland and marina features in OR confluences. Both organic and inorganic tracers statistically differentiate sediment from stream and river end‐members. Carbon and nitrogen stable isotopes produce greater uncertainty in fingerprinting results than inorganic elemental tracers. Uncertainty analysis of the nonconservative tracer term in the organic matter fingerprinting application estimates an apparent enrichment of the carbon stable isotopes during instream residence, and the nonconservativeness is quantified with a statistical approach unique to the fingerprinting literature. Wetland and marina features in OR confluences impact 42% and 11% of tributary drainage areas, respectively. Sediment dynamics show wetland and marina confluences experience deposition from river backwaters with longitudinally linear and nonlinear patterns, respectively, from sediment sources.  相似文献   
72.
Coastal areas of Iran are heavily affected by urbanisation, industrialisation, and maritime activities. One consequence of this environmental pressure is the contaminants accumulation, as heavy metals, into the marine ecosystem. In this review, the coastal areas in the north and south of the country were assessed for lead (Pb) contamination of, one of the most toxic metals found in the environment. All studies conducted during 2006–2016 with at least 10 specimens that reported the mean and standard deviation of Pb were considered in this review. Heterogeneity between studies was assessed using the Q and I2 statistics. The Pb mean concentration overall studies was estimated to be 21.88?µg/g (95% CIs: 16.25–27.50). Random effect model showed no statistical difference in mean Pb concentration levels between south and north coasts. However, the variability in Pb mean concentrations within southern coasts was considerable and statistically significant. Moreover, the Pb concentrations in the northern coasts of Persian Gulf and Oman Sea, in south of Iran, decreased in the following order Hormozgan > Khuzestan > Sistan-VA-Balluchestan > Bushehr while in the southern coasts of Caspian Sea, in north of Iran, decreased in the order Guilan > Mazandaran > Golestan.  相似文献   
73.
Mitigation and offset programs designed to compensate for ecosystem function losses due to development must balance losses from affected ecosystems with gains in restored ecosystems. Aggregation rules applied to ecosystem functions to assess site equivalence are based on implicit assumptions about the substitutability of functions among sites and can profoundly influence the distribution of restored ecosystem functions on the landscape. We investigated the consequences of rules applied to the aggregation of ecosystem functions for wetland offsets in the Beaverhill watershed in Alberta, Canada. We considered the fate of 3 ecosystem functions: hydrology, water purification, and biodiversity. We set up an affect‐and‐offset algorithm to simulate the effect of aggregation rules on ecosystem function for wetland offsets. Cobenefits and trade‐offs among functions and the constraints posed by the quantity and quality of restorable sites resulted in a redistribution of functions between affected and offset wetlands. Hydrology and water purification functions were positively correlated with one another and negatively correlated with biodiversity function. Weighted‐average rules did not replace functions in proportion to their weights. Rules prioritizing biodiversity function led to more monofunctional wetlands and landscapes. The minimum rule, for which the wetland score was equal to the worst performing function, promoted multifunctional wetlands and landscapes. The maximum rule, for which the wetland score was equal to the best performing function, promoted monofunctional wetlands and multifunctional landscapes. Because of implicit trade‐offs among ecosystem functions, no‐net‐loss objectives for multiple functions should be constructed within a landscape context. Based on our results, we suggest criteria for the design of aggregation rules for no net loss of ecosystem functions within a landscape context include the concepts of substitutability, cobenefits and trade‐offs, landscape constraints, heterogeneity, and the precautionary principle.  相似文献   
74.
根据垂直潜流人工湿地发生堵塞的成因主要是基质层中不可滤物质积累的结论,在分析垂直潜流人工湿地堵塞物形态及成分粒径的基础上,首次提出了基质间不可滤物质积累微观概念模型的假设;并根据微观概念模型,在考虑生物膜、无机物积累等动态变化因素条件下提出基质间完全堵塞所需时间、基质表面发生雍水所需时间及基质渗透系数随时间变化的关系.  相似文献   
75.
Sulphur cycling and its correlation to removal processes under dynamic redox conditions in the rhizosphere of helophytes in treatment wetlands are poorly understood. Therefore, long-term experiments were performed in laboratory-scale constructed wetlands treating artificial domestic wastewater in order to investigate the dynamics of sulphur compounds, the responses of plants and nitrifying microorganisms under carbon surplus conditions, and the generation of methane. For carbon surplus conditions (carbon:sulphate of 2.8:1) sulphate reduction happened but was repressed, in contrast to unplanted filters mentioned in literature. Doubling the carbon load caused stable and efficient sulphate reduction, rising of pH, increasing enrichment of S(2-) and S(0) in pore water, and finally plant death and inhibition of nitrification by sulphide toxicity. The data show a clear correlation of the occurrence of reduced S-species with decreasing C and N removal performance and plant viability in the experimental constructed wetlands.  相似文献   
76.
分析了洪泽湖湿地生态系统属性及其在南水北调工程实施后的演变趋势,利用野外实验研究,在生境改变条件下,适用于不同湿地退化状况的人工辅助恢复技术;在实验监测的基础上,对洪泽湖几种典型湿地生态系统的生态功能进行了定量评价,为生态恢复工程的设计提供必要的技术支持。  相似文献   
77.
人工神经元网络对水处理系统建模适应性的研究   总被引:10,自引:0,他引:10  
针对水处理系统的特点和研究中的难点,引入人工神经元网络的理论和思想,提出了水处理系统的神经网络分析方法.通过建立基于BP人工神经元网络的臭氧生物活性炭系统的模型,具体地考察了人工神经元网络对水处理系统建模的适应性,使水处理系统的研究迈向智能化和控制化.  相似文献   
78.
涤沦仿真丝印染废水治理技术的研究及其应用   总被引:8,自引:0,他引:8  
采用化学法去除对苯二甲酸,对高浓度涤纶仿真丝印染废水进行治理。结果表明:该技术对碱减量废水中CODCr的去除有显著的效果。当废水的pH值在12~14,CODCr含量在10000~33000mg/L时,将废水的pH值调节到4~6,出水CODCr能降至1000~2700mg/L之间,CODCr去除率为77%~955%。为涤纶纺真丝印染废水治理达标排放奠定了基础  相似文献   
79.
2005~2006年,在蓄水初期的大房郢水库采用投放滤食性鱼类鱼种、移殖螺、蚌、浅水区移植沉水植物、上游湿地扩大香蒲生长面积、消落区以上范围栽培杨树林和防护带等生物操纵与人工湿地技术相结合的方法改善水质的研究,结果表明:自2005年以来,该水库未再出现过蓝藻水华,水体富营养化得到了有效控制,水质已基本稳定在中-富营养型水平。由此认为,利用生物操纵与人工湿地技术结合为改善大房郢水库水质发挥了重要作用。  相似文献   
80.
湿地是分布于陆生生态系统和水生生态系统之间具有独特水文、土壤、植被与生物特征的生态系统。盛泽湖是位于苏州相城区东北部的天然浅水湖泊,东临阳澄湖,面积为3.86 km^2。由于当地居民对湖泊进行过度养殖和捕捞、大量的围湖造田和进行农业生产建设、工农业废水和生活污水直接排入水体及湿地附近砖瓦厂的取土等原因引起盛泽湖湿地的生态退化。用生态规划的方法来探讨如何对盛泽湖湿地进行生态恢复,并从环境效益、社会效益和经济效益来分析规划方案实施后的效果。  相似文献   
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