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以黄河三角洲退化湿地人工引水恢复区为研究对象,采用野外植被调查、土壤采样结合室内实验方法,对植被的种类、密度、盖度、频度和重要值以及土壤含水量、pH值、有机质、全氮以及全磷等指标进行分析,旨在探讨人工引水恢复工程对黄河三角洲退化湿地所产生的生态效应。结果表明：随着水分条件的改善,恢复区植被呈现出正向演替;恢复区土壤含水量明显高于未恢复区,pH值则明显降低,土壤有机质含量高于未恢复区,土壤全氮、全磷含量变化不大。可见,引水恢复工程已经使退化湿地的生态环境得到了一定程度的改善,淡水资源仍是制约退化湿地恢复的关键因素。 相似文献
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珠江流域水质现状及以区域合作为特色的水污染控制措施 总被引：3，自引：1，他引：3
通过对珠江流域水质现状的全面分析,找出污染源,发现水中COD、油类污染物、氨氮、总磷等超标,并有水质进一步恶化和水体富营养化的可能.根据珠江流域的水污染特点,提出了相应的水污染控制措施,主要有落实各项水污染控制工程、完善政策法规、强调舆论监督、加强治理力度等,并且将区域合作思想贯穿整个水污染控制工程. 相似文献
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寒冷地区道路表面除雪化冰使用的化学融雪剂随着地表径流进入水体,将影响水生态系统中的水生生物正常生长,并破坏水生态系统平衡。为研究化学融雪剂对水生生物的毒性效应,分析了不同浓度有机融雪剂对小球藻生长特征、藻细胞光和色素、蛋白质及多糖含量的影响。结果表明：浓度为2 g·L-1时有机融雪剂对小球藻生长无明显影响,当融雪剂浓度为4 g·L-1时,小球藻细胞生长表现出明显抑制效应,且抑制效应随融雪剂浓度增加呈显著上升趋势(P<0.01);当融雪剂浓度小于4 g·L-1时,有机融雪剂对小球藻细胞内叶绿素a合成有明显促进作用,但随着有机融雪剂处理浓度升高,藻细胞内叶绿素a含量逐渐下降。当融雪剂的处理浓度大于4 g·L-1的时候,藻细胞内蛋白质和多糖含量与对照组相比呈显著下降趋势(P<0.01)。这说明融雪剂浓度高于4 g·L-1时会抑制水体中小球藻正常生长繁殖,破坏藻体细胞,最终导致水生态系统平衡被破坏。 相似文献
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长江上游MODIS影像的水体自动提取方法 总被引：10，自引：0，他引：10
利用MODIS资料,分析了长江上游不同水体及其它主要地物在1～7通道的光谱特征,分析发现,水体混合像元在可见光的光谱特征与山体的阴影、云的阴影、城镇等的光谱特征具有很好的相似性,仅采用近红外波段和红光波段的方法不能有效提取出研究区的水体.提出综合采用归一化差分水指数、积雪指数以及可见光、近红外多通道信息的方法,逐步提取出研究区的水体及混合水体像元. 相似文献
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城市中水体布局对大气环境的影响 总被引：2，自引：0，他引：2
城市下垫面状况在很大程度上决定城市大气物理环境的特征。在城市区域增加湿地等自然地表有利于城市的减温增湿,促使局地流场发生变化,改善局地微气象条件以及大气物理环境。城市规划大气物理环境多尺度数值模拟系统为城市规划大气物理环境定量评估提供了有效的模拟工具。利用该系统中的城市尺度模式模拟了水体布局为集中型和分散型,水体面积占有率分别为4%、8%、12%和16%条件下,城市大气温度、湿度、风速、城市大气扩散条件的变化及其对城市大气环境的影响,利用北京市城市水体气象观测数据,分析了水体周边和商业区、交通区温、湿度的差异,并对模式模拟结果进行了验证,揭示了城市水体布局对城市大气物理环境影响的可能机制。模拟和观测结果显示,城市水体布局会对城市微气象环境产生一定影响。无论分散型或集中型布局,城市水体面积的增加,都在一定程度上使城市气温降低、湿度增加、平均风速增大。比较而言,分散型水体布局对城市区域微气象环境的影响更为显著。 相似文献
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通过对珠江流域水质现状的全面分析,找出污染源,发现水中COD、油类污染物、氨氮、总磷等超标,并有水质进一步恶化和水体富营养化的可能。根据珠江流域的水污染特点,提出了相应的水污染控制措施,主要有落实各项水污染控制工程、完善政策法规、强调舆论监督、加强治理力度等,并且将区域合作思想贯穿整个水污染控制工程。 相似文献
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为了解有机磷农药乙酰甲胺磷污染对本土水生敏感性物种斜生栅藻(Scenedesmus obliquus)的毒性效应,在实验室条件下采用静态毒性试验,研究了乙酰甲胺磷对斜生栅藻96 h急性毒性效应,并在急性试验基础上进行慢性试验,分析了斜生栅藻连续染毒14 d的叶绿素质量浓度、可溶性蛋白质量分数以及丙二醛(MDA)质量摩尔浓度的变化.结果表明:乙酰甲胺磷的96 h EC50为482.9 mg/L,属低毒农药,但在1 mg/L低质量浓度下可促进藻细胞生长;乙酰甲胺磷对栅藻光合作用无明显影响,但可通过干扰藻细胞代谢活动和引起膜脂过氧化反应,对斜生栅藻产生毒性作用;可溶蛋白和MDA可作为有效的生物标志物对农药引起的毒性做出评价.研究结果可为本土水生敏感性物种的保护和农药安全使用标准的制定提供理论依据. 相似文献
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Torben O. Sonnenborg Klaus Hinsby Lieke van Roosmalen Simon Stisen 《Climatic change》2012,113(3-4):1025-1048
The hydrology of coastal catchments is influenced by both sea level and climate. Hence, a comprehensive assessment of the impact of climate change on coastal catchments is a challenging task. In the present study, a coupled groundwater–surface water model is forced by dynamically downscaled results from a general circulation model. The effects on water quantity and quality of a relatively large lake used for water supply are analyzed. Although stream inflow to the lake is predicted to decrease during summer, the storage capacity of the lake is found to provide a sufficient buffer to support sustainable water abstraction in the future. On the other hand, seawater intrusion into the stream is found to be a significant threat to the water quality of the lake, possibly limiting its use for water supply and impacting the aquatic environment. Additionally, the results indicate that the nutrient load to the lake and adjacent coastal waters is likely to increase significantly, which will increase eutrophication and have negative effects on the surface water ecology. The hydrological impact assessment is based on only one climate change projection; nevertheless, the range of changes generated by other climate models indicates that the predicted results are a plausible realization of climate change impacts. The problems identified here are expected to be relevant for many coastal regimes, where the hydrology is determined by the interaction between saline and fresh groundwater and surface water systems. 相似文献
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A significant challenge in resource management is addressed: the perceived trade-off between economic growth and ecosystem restoration and conservation. Traditional approaches to management regard restoration as a potential cost to economic productivity. In this study we show that by considering a broader range of economic values, including ecosystem services values, an argument can be made that restoration of lake ecosystems also leads to favourable economic outcomes when commonly disregarded values are considered. Our case study analyses the ecological outcomes of different catchment mitigation and land use scenarios in terms of water quality results in a lake, assessing changes in land use values based on opportunity costs, and ecosystem services values. We show that when considering the value of ecosystem services, intensive agricultural land use is not necessarily the most economically valuable form of land use within a lake catchment. Indeed, a shift towards alternative land uses within a catchment can lead to both ongoing economic benefits and improvements in water quality. In this context, land-use change offers an option for water quality improvement that minimises lake and land mitigation costs, while adding value to catchment land use. An argument is made supporting land use change towards indigenous forest types, which can sustain alternative sources of income such as a range of recreational values, while supporting important ecosystem functions for the region. 相似文献
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基于MODIS植被指数的太湖蓝藻信息提取方法研究 总被引：4，自引：1，他引：3
有效地提取蓝藻水华信息对分析蓝藻动态分布有重要意义,而卫星遥感技术是进行太湖水质监测与保护的措施之一.本文以2007年7月25日Terra/MODIS数据为主要数据源,用比值植被指数(Irv)、归一化植被指数(Indv)和增强型植被指数(Iev),研究提取太湖蓝藻信息.结果表明:植被指数可以有效提取遥感影像中的蓝藻水华信息,其中Indv是应用效果较好的植被指数之一;在掩膜处理后,用Indv提取了太湖蓝藻的面积分布信息,效果较好;此外,选取Indv为测试变量,利用决策树分类法,有效地把蓝藻水华高浓度覆盖区、中浓度覆盖区和轻浓度覆盖区分开来,为准确掌握太湖蓝藻发生、发展趋势和发生程度提供可靠信息. 相似文献
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Yuanzhi Zhang Hongtao Duan Hongyan Xi Zhaojun Huang JinYeu Tsou Tingchen Jiang 《大气与海洋》2018,56(4):277-288
AbstractAquatic plants and lake bottoms in optically shallow waters (OSWs) wield great influence on reflectance spectra, resulting in the inapplicability of most existing bio-optical models for water colour remote sensing in lakes. Based on radiative transfer theory and measured spectra from a campaign for Lake Taihu in October 2008, absorption and backscattering coefficients were used to simulate the remote-sensing reflectance, which are considered to be reliable if matched to their measured counterparts. Several cases of measured spectra at different depths, Secchi disk depth transparency, and aquatic plant height and coverage were analyzed thoroughly for spectral properties. The contribution of aquatic plants was evaluated and compared with the measured and simulated remote-sensing reflectance values. This is helpful for removing the influence of aquatic plants and lake bottoms from the spectra and for constructing an improved chlorophyll a retrieval model for OSWs, such as that for Lake Taihu, China. 相似文献
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Intensive agriculture and densely populated areas represent major sources of nutrient pollution for European inland and coastal waters, altering the aquatic ecosystems and affecting their capacity to provide ecosystem services and support economic activities. Ambitious water policies are in place in the European Union (EU) for protecting and restoring aquatic ecosystems under the Water Framework Directive and the Marine Strategy Framework Directive. This research quantified the current pressures of point and diffuse nitrogen and phosphorus emissions to European fresh and coastal waters (2005–2012), and analysed the effects of three policy scenarios of nutrient reduction: 1) the application of measures currently planned in the Rural Development Programmes and under the Urban Waste Water Treatment Directive (UWWTD); 2) the full implementation of the UWWTD and the absence of derogations in the Nitrates Directive; 3) high reduction of nutrient, using best technologies in wastewaters treatment and optimal fertilisation in agriculture. The results of the study show that for the period 2005–2012, the nitrogen load to European seas was 3.3–4.1 TgN/y and the phosphorus load was 0.26–0.30 TgP/y. Policy measures supporting technological improvements (third scenario) could decrease the nutrient export to the seas up to 14% for nitrogen and 20% for phosphorus, improving the ecological status of rivers and lakes, but widening the nutrient imbalance in coastal ecosystems (i.e. increasing nitrogen availability with respect to phosphorus), affecting eutrophication. Further nutrient reductions could be possible by a combination of measures especially in the agricultural sector. However, without tackling current agricultural production and consumption system, the reduction might not be sufficient for achieving the goals of EU water policy in some regions. The study analysed the expected changes and the source contribution in different European regional seas, and highlights the advantages of addressing the land-sea dynamics, checking the coherence of measures taken under different policies. 相似文献
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辽宁北部典型流域水生态功能三级分区与水生态服务功能评价 总被引：1，自引：0，他引：1
流域水生态功能区划是水生态和水资源综合保护的重要前提和基础。在综合分析调查辽河流域辽北地区典型流域自然环境特征、水文数据、地理信息数据的基础上,结合辽河流域水生态功能一级、二级分区结果,建立水生态功能三级分区指标体系,对辽宁省辽河流域内清河、汎河流域进行水生态功能三级分区。结果表明：清河流域可分为7个水生态功能三级区,汎河流域可分为4个水生态功能三级区,水生态服务功能类型共划分为5类：生物多样性与生物栖息地维持功能,产品提供与农业生产功能,水源涵养与水文调蓄功能,人居保障与城市发展功能,水土保持与生态修复功能。水生态功能三级分区结果为辽河流域实施水生态综合管理提供了科技支撑,同时也为中国水生态功能分区技术规范的制定提供了科学依据。 相似文献
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近地面风场变化对太湖蓝藻暴发影响的数值研究 总被引：5，自引：1，他引：4
蓝藻水华是在特定的气象和水文条件下,已成为优势种群的蓝藻群体在水体中发生水平、垂直位置的改变而形成.选取2007年6月24日和9月8日发生的2次蓝藻暴发个例,利用WRFV2模式进行较高分辨率数值模拟,研究了在蓝藻成为优势群体之后的上浮积聚阶段近地面风向风速对蓝藻水华面积变化和活动范围的影响.通过数值模拟结果与EOS/MODIS卫星遥感监测到的蓝藻信息的对比分析发现,蓝藻的活动对湖区近地面风场变化的反应相当迅速,蓝藻大面积暴发过程往往对应着有利的风向风速变化:如风速小、系统性东北风、辐散环流等.研究表明通过对太湖地区各气象要素的高分辨率数值模拟,可以预测蓝藻的暴发和演变情况,为太湖蓝藻暴发的预测预警提供气象依据. 相似文献
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The response of Lake Tahoe to climate change 总被引：2，自引：0，他引：2
G. B. Sahoo S. G. Schladow J. E. Reuter R. Coats M. Dettinger J. Riverson B. Wolfe M. Costa-Cabral 《Climatic change》2013,116(1):71-95
Meteorology is the driving force for lake internal heating, cooling, mixing, and circulation. Thus continued global warming will affect the lake thermal properties, water level, internal nutrient loading, nutrient cycling, food-web characteristics, fish-habitat, aquatic ecosystem, and other important features of lake limnology. Using a 1-D numerical model—the Lake Clarity Model (LCM) —together with the down-scaled climatic data of the two emissions scenarios (B1 and A2) of the Geophysical Fluid Dynamics Laboratory (GFDL) Global Circulation Model, we found that Lake Tahoe will likely cease to mix to the bottom after about 2060 for A2 scenario, with an annual mixing depth of less than 200 m as the most common value. Deep mixing, which currently occurs on average every 3–4 years, will (under the GFDL B1 scenario) occur only four times during 2061 to 2098. When the lake fails to completely mix, the bottom waters are not replenished with dissolved oxygen and eventually dissolved oxygen at these depths will be depleted to zero. When this occurs, soluble reactive phosphorus (SRP) and ammonium-nitrogen (both biostimulatory) are released from the deep sediments and contribute approximately 51 % and 14 % of the total SRP and dissolved inorganic nitrogen load, respectively. The lake model suggests that climate change will drive the lake surface level down below the natural rim after 2085 for the GFDL A2 but not the GFDL B1 scenario. The results indicate that continued climate changes could pose serious threats to the characteristics of the Lake that are most highly valued. Future water quality planning must take these results into account. 相似文献
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Climate-induced increase in surface temperatures can impact hydrologic processes of a watershed system. This study uses a continuous simulation model to evaluate potential implications of increasing temperature on water quantity and quality at a regional scale in the Connecticut River Watershed of New England. The increase in temperature was modeled using Intergovernmental Panel on Climate Change (IPCC) high and low warming scenarios to incorporate the range of possible temperature change. It was predicted that climate change can have a significant affects on streamflow, sediment loading, and nutrient (nitrogen and phosphorus) loading in a watershed. Climate change also influences the timing and magnitude of runoff and sediment yield. Changes in variability of flows and pollutant loading that are induced by climate change have important implications on water supplies, water quality, and aquatic ecosystems of a watershed. Potential impacts of these changes include deficit supplies during peak seasons of water demand, increased eutrophication potential, and impacts on fish migration. 相似文献
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This paper represents an attempt to combine the output of several models that deal with future climatic, hydrologic and economic conditions in the Great Lakes and makes some predictions about the possible impact of one scenario of 2 × CO2 climate on Great Lakes shipping. It is realized that there is a great deal of uncertainty in all the models and that improvements are continually being made. Data from a General Circulation Model of future temperature and precipitation in the Great Lakes basin, a Great Lakes levels and flows model from the Canada Centre for Inland Waters and an International Joint Commision's Great Lakes economic model modified by the University of Wisconsin were used. The 1900–1976 period of lake levels and flows was used. The hydrologic model indicated that future mean lake levels may be reduced by one-half meter, and that the extreme low levels of the mid 1960's could occur 77% of the time in the future. No ice cover is predicted for any lake except Erie, permitting an eleven month shipping season. Five scenarios of future impact on shipping were evaluated. It was found that mean annual shipping costs may increase by 30% and the frequency of years when costs exceed those of the period of low lake levels (1963–65) could rise to 97%. Possible policy options in a future with climatically induced lower lake levels could include regulation to keep levels artificially high by diversions into the system, or increased dredging of the connecting channels. 相似文献