白洋淀生态需水:进展及展望   总被引：1，自引：0，他引：1  

杨薇  赵彦伟  刘强  孙涛 《湖泊科学》2020,32(2):294-308

采用文献计量、统计分析等手段收集了国内外关于白洋淀生态需水核算的研究成果,系统梳理了15种白洋淀生态需水核算方法,获得了白洋淀不同时间尺度、不同等级生态需水核算结果,并结合雄安新区规划对白洋淀生态需水核算存在的问题及未来的需求提出了展望统计结果表明,白洋淀最小生态水位为7.45±0.66 m,适宜水位为8.61±0.52 m,最大水位为9.46±0.51 m;各等级生态需水月际变化趋势大致相同,8 9月最大,5月最小,但各月不同等级生态需水量的变幅较大;白洋淀最小生态补水量为1.35亿m~3,适宜补水量2.40亿m~3,最大生态补水量6.20亿m~3从支撑雄安新区规划建设的角度来看,目前白洋淀生态需水核算中面临的不足主要集中在生态管理目标和方法选择导致核算结果差异较大、缺乏淀区生态需水机制的阐释、生态需水核算时间尺度较粗略、未考虑淀区空间异质性的需水差异以及忽略河湖水文连通关系与过程5个方面;最后,以恢复白洋淀良性生态系统为导向,从分级分区开展白洋淀生态需水精细核算、分时分段淀区生态需水量质耦合模拟和考虑河湖沼连通的淀区水动力过程恢复3个方面提出了未来研究的建议与展望.  相似文献   

Hydrological management strategies for the control of algal blooms in regulated lowland rivers     

Jian Li  Wei Yin  Haiyan Jia  Xiaokang Xin 《水文研究》2021,35(6):e14171

Reservoirs of lowland floodplain rivers with eutrophic backgrounds cause variations in the hydrological and hydraulic conditions of estuaries and low-dam reservoir areas, which can promote planktonic algae to proliferate and algal bloom outbreaks. Understanding the ecological effects of variations in hydrological and hydraulic processes in lowland rivers is important for algal bloom control. In this study, the middle and lower reaches of the Han River, China, a typical regulated lowland river with a eutrophic background, are selected. Based on the effect of hydrological and hydraulic variability on algal blooms, a hydrological management strategy for river algal bloom control is proposed. The results showed that (a) differences in river morphology and background nutrient levels cause significant differences in the critical threshold flow velocities for algal bloom outbreaks between natural river and low-dam reservoir sections; there is no uniform threshold flow velocity for algal bloom control. (b) There are significant differences in the river hydrological/hydraulic conditions between years with and without algal blooms. The average river flow, water level and velocity in years with algal blooms are significantly lower than those in years without algal blooms. (c) For different river sections where algal blooms occur and to meet the threshold flow velocities, the joint operation of cascade reservoirs and diversion projects is an effective method to prevent and control algal blooms in regulated lowland rivers. This study is expected to deepen our understanding of the ecological significance of special hydrological processes and guide algal bloom management in regulated lowland rivers.  相似文献   

广盐性鱼类渗透压适应性与生理可塑性机制研究     

马爱军  崔文晓  刘志峰  张金生  黄智慧  杨双双  刘晓菲  杨凯  张薇 《海洋与湖沼》2018,49(6):1308-1317

拥有强大的渗透压调节能力对广盐性鱼类的生存至关重要。目前,关于鱼类渗透压调节机制已有不少研究,但均存在较大的局限性。本文从广盐性鱼类渗透压信号转导机制、渗透胁迫的细胞调控机制、渗透调控的内分泌调节机制和无机离子通道和转运蛋白介导的渗透调控等方面对广盐性鱼类的渗透压适应性和生理可塑性机制进行分析,以期从分子、细胞、通路和生理等层次初步探索广盐性鱼类盐度胁迫后的可塑性表型变化和不同盐度条件下的应答机制,为广盐性鱼类的渗透压调节机制的深入研究奠定基础。对广盐性鱼类渗透压适应性与生理可塑性机制研究,有助于研究其环境适应机理,促进野生鱼种的人工化养殖以及新品种的育种从而提高经济效益、社会效益和生态效益,对促进水产养殖学进步以及养殖业的发展具有重要意义,同时,为研究广盐性鱼类的渗透压调节机制开辟新的研究方向。  相似文献   

潮流界以下河段航道整治水位确定方法研究——以长江江阴以下河段为例     

徐元  贾雨少 《海洋工程》2018,36(2):64-72

在总结分析现有整治水位确定方法的基础上,根据潮流界以下河段的水沙运动特性,本文提出一种基于输沙能力的航道整治水位确定方法。考虑上游来水、下游潮汐为独立事件,统计潮流界以下河段上游来水、下游潮汐不同等级组合出现的频率,采用数学模型计算相应组合下河段沿程的潮位、流速过程,以流速四次方代表水流的输沙能力,统计不同潮位等级对应的综合净输沙能力,确定最大综合净输沙能力对应的水位为(最优)航道整治水位。以长江下游白茆沙水道和福姜沙水道为例,计算了所在河段的航道整治水位,并探讨了起动流速对整治水位计算的影响和最高整治水位概念对工程的意义。  相似文献   

2012-2016年调水调沙对黄河口海域大型底栖动物群落结构的影响     

李少文  李凡  宋秀凯  张明亮 《海洋学报(英文版)》2020,39(10):120-128

为了明确黄河调水调沙对河口海域大型底栖动物群落结构的影响，本研究于2012至2016年调水调沙后进行了大型底栖动物样品的采集工作。整个研究时期共鉴定出大型底栖动物7门138种，生物量和丰度2012年显著高于2016年，生物量年间无显著差异；研究时期内优势种以小型多毛类为主，鲜见软体动物、节肢动物和棘皮动物，其中2016年优势种全部为小个体多毛类；MDS显示，随时间的推移距河口不同距离梯度的大型底栖动物逐渐演变为相同的群落结构，且Shannon-Wiener多样性指数和Margalef丰富度指数呈下降趋势；CCA显示研究海域主要底栖动物种类的生态需求为高中值粒径、低溶解氧、pH、黏土和硫化物含量。本研究推测调水调沙工程一定程度上影响了底层生物群落结构，特别是研究海域的A断面。  相似文献   

Environmental regulation and innovation: Evidence from China     

《Global Environmental Change》2022

The relevance of analyzing effects of environmental regulation on innovation cannot be overemphasized. In this paper, we first develop a theoretical model to predict how command-and-control environmental regulation affects innovation, and then we derive its channels. Using the difference-in-difference-in-differences strategy and a comprehensive dataset at city-industry-year level of manufacturing sectors in China, we found that the more stringent environmental regulations that are faced by cities, measured by the reduction targets of chemical oxygen demand (COD) and sulfur dioxide (SO₂) during the eleventh Five-Year Plan, are negatively associated with innovation. Thus, the evidence contradicts the Porter Hypothesis. On average, a one standard deviation increase in the reduction targets of COD (SO₂) is associated with a 0.023 (0.016) standard deviation decrease in the innovation index. We controlled carefully for various potential confounders, and the results were supported by robustness and falsification checks. There exists an evident heterogeneity effect across regions and industries with different pollution intensities. The channel analysis shows that stricter environmental regulation also accounts for a sharp decline in labor demand, firm entry, and inbound foreign direct investment. Our findings are also robust to alternative measures for innovation and environmental regulation.  相似文献   

黄河口清水沟河道的冲淤过程与模拟          下载免费PDF全文

郑珊  吴保生  周云金  王开荣  韩沙沙 《水科学进展》2018,29(3):322-330

为揭示黄河口清水沟河道长时段的冲淤演变规律并建立其冲淤计算方法,分析了清水沟1976—2015年的时空冲淤演变过程,采用河床演变的滞后响应模型,考虑河口来水来沙及河道延伸与蚀退的影响,建立了清水沟累计冲淤量的计算方法。结果表明:1976—1980年改道初期清水沟改道点上游先冲后淤,改道点下游淤滩塑槽,淤积量随着下游河道展宽而增加,1980年后改道点上、下游河道冲淤过程趋于一致;受水沙条件等因素影响,1980—1986年清水沟主槽冲刷展宽,之后主槽淤积萎缩;1996年清八改汊和2002年小浪底水库"调水调沙"原型试验以来,河道转淤为冲,2002年后河道冲刷速率随时间指数衰减;河床演变的滞后响应模型可计算清水沟长时段的冲淤过程,该方法可为预测未来清水沟冲淤演变趋势提供科学参考。  相似文献   

云南云龙天池枝角类群落演替对1950s以来人类活动影响信号的识别     

索旗  陈光杰  孔令阳  徐会明  李静  张涛  王露  周起  郑昕 《湖泊科学》2022,34(5):1735-1750

从1950s开始, 云南地区部分湖泊受到了水文调控(如筑坝)和鱼类引入等流域开发活动的直接影响, 湖泊水环境与生态系统结构已出现明显改变. 开展浮游动物群落的长期生态响应评价有助于认识气候波动和人为胁迫的影响模式. 本文选取云龙天池进行了沉积物记录分析, 在重建过去100年环境变化历史的基础上开展了枝角类群落的多指标分析(物种组成、个体大小、生物量等), 进一步结合多变量分析识别了枝角类群落构建的关键驱动因子. 结果显示, 云龙天池在过去100年间经历了明显的水位波动, 约1962年以前水位较低, 1950s起的水文调控(筑坝)导致湖泊水位波动上升, 2006年以来略有下降. 枝角类群落随水位波动呈现由底栖种向浮游种占优转变的模式, 并在2006年以来底栖种略有增加. 总体上, 低水位时期底栖枝角类占优, 高水位时期浮游枝角类占优. 水体营养水平也对枝角类群落产生了较为显著的影响. 在沉积物总氮和有机质通量上升时, 长额象鼻溞(Bosmina longirostris)相对丰度和枝角类浓度都明显上升. 枝角类象鼻溞个体大小表明, 1969年鱼类引入后象鼻溞的壳长、壳刺长度、触角长度显著减小, 反映了鱼类捕食压力上升的影响. 本研究进一步揭示了水文调控和鱼类引入对湖泊环境和生物群落结构的驱动影响. 其中, 1960s以前云龙天池处于自然波动的状态, 湖泊环境和枝角类群落变化主要受气候(如降水、气温)的影响; 1960s以来人类活动的影响强度已经掩盖了气候变化的信号, 成为影响湖泊生态演化轨迹的主要因素. 为了开展有效的湖泊保护与生态治理, 有必要综合评估水文调控、鱼类引入等人类活动对湖泊生态健康的长期影响.  相似文献   

中国西部寒区流域冰川水文调节功能研究     

贺青山  杨建平  陈虹举  王彦霞  唐凡  冀钦  葛秋伶 《冰川冻土》2021,43(5):1512-1522

冰川作为固体水库以“削峰填谷”的形式显著调节径流丰枯变化,冰川的水文调节功能对于中国西北干旱区至关重要。使用现有VIC-CAS模型模拟得到中国西部寒区2014—2100年径流预估数据,从趋势和波动变化相结合的视角,基于径流变差系数法,构建了冰川水文调节指数（Glacier_R）,分析了9个寒区流域冰川径流变化的稳定性,详细剖析了历史时期（1971—2010年）和未来到21世纪末这些流域冰川水文调节功能的强弱变化。结果表明：历史时期及RCP2.6和RCP4.5情景下,除长江流域外,青藏高原其余流域的冰川径流减小时间节点为2020s,西北内陆河流域则为2010s。历史时期及RCP2.6和RCP4.5情景下至21世纪末,尽管西部寒区大部分流域的冰川径流呈减少趋势,但波动幅度减小或无明显变化,冰川径流稳定性增强或无变化。总体上,西北内陆河流域的冰川水文调节功能较高,青藏高原流域的冰川水文调节功能较低。RCP2.6和RCP4.5情景下,至21世纪末,西部寒区各流域冰川水文调节功能均呈现减弱趋势,西北内陆河流域减弱更加显著,如RCP4.5情景下,木扎提河冰川水文调节功能降幅达25.4%,而青藏高原各流域的冰川水文调节功能一直处于较低水平。从年代际变化来看,1970s—2010s是寒区流域冰川水文调节功能较强的时期,1980s和2000s两个时段冰川水文调节功能尤强;RCP2.6和RCP4.5情景下,未来到21世纪末,冰川调节功能明显减弱。减弱的时间节点不同,最早为1970s,最晚为2020s。  相似文献   

Downstream effects of stream flow diversion on channel characteristics and riparian vegetation in the Colorado Rocky Mountains,USA          下载免费PDF全文

Simeon T. Caskey  Tyanna S. Blaschak  Ellen Wohl  Elizabeth Schnackenberg  David M. Merritt  Kathleen A. Dwire 《地球表面变化过程与地形》2015,40(5):586-598

Flow diversions are widespread and numerous throughout the semi‐arid mountains of the western United States. Diversions vary greatly in their structure and ability to divert water, but can alter the magnitude and duration of base and peak flows, depending upon their size and management. Channel geometry and riparian plant communities have adapted to unique hydrologic and geomorphic conditions existing in the areas subject to fluvial processes. We use geomorphic and vegetation data from low‐gradient (≤3%) streams in the Rocky Mountains of north‐central Colorado to assess potential effects of diversion. Data were collected at 37 reaches, including 16 paired upstream and downstream reaches and five unpaired reaches. Channel geometry data were derived from surveys of bankfull channel dimensions and substrate. Vegetation was sampled using a line‐point intercept method along transects oriented perpendicular to the channel, with a total of 100 sampling points per reach. Elevation above and distance from the channel were measured at each vegetation sampling point to analyze differences in lateral and vertical zonation of plant communities between upstream and downstream reaches. Geomorphic data were analyzed using mixed effects models. Bankfull width, depth, and cross‐sectional area decreased downstream from diversions. Vegetation data were analyzed using biological diversity metrics, richness, evenness and diversity, as well as multivariate community analysis. Evenness increased downstream from diversions, through reduced frequency of wetland indicator species and increased frequency of upland indicator species. Probability of occurrence for upland species downstream of a diversion increases at a greater rate beginning around 0·5 m above active channel. The results suggest that channel morphology and riparian plant communities along low‐gradient reaches in montane environments in the Colorado Rocky Mountains are impacted by diversion‐induced flow alteration, with the net effect of simplifying and narrowing the channel and homogenizing and terrestrializing riparian plant communities. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献