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1.
A former meander of the Upper Rhône River, France, is completely filled with silt and occurs as a forested wetland. Bosminidae and Chydoridae (Crustacea, Cladocera) remains are analysed from a 6-m sediment core that reaches coarse sand and gravel layers deposited by running water. The lower layer of fine sediment, deposited by still water after the meander had been cut off, was dated at 1666±211 BC. The likely end of aquatic succession was dated at 800±150 AD. The results, processed using Factorial Correspondence Analysis, suggest 3 phases during the aquatic succession. Phase I, corresponding to open water conditions, is very short. The following phases, indicating the development of macrophyte stands, then a decrease in depth, extend much longer. The unexpectedly long duration (1000–2000 years) of these macrophyte-dominated and marshy phases may be explained by a progressive rise in the mean water level of the Rhône River. The causes of this water level rise may be related to climatic and/or fluvial dynamics changes. 相似文献
2.
淮河中上游浮游植物时空分布特征及关键环境影响因子识别 总被引：2，自引：2，他引：0
浮游植物是水生态系统的初级生产者,直接影响着水生态系统的结构、功能与稳定性。基于2012-2014年淮河流域沙颍河—淮干中游浮游植物和水质4次汛期和非汛期采集数据,利用物种优势度和多样性指数对浮游植物的时空分布进行表征,并利用冗余度分析、偏相关性分析等方法探索了淮河中上游流域的多种水环境因子对浮游植物时空分布的影响。结果表明,从时间变化上看,2012-2014年浮游植物密度呈现逐年递减趋势;从空间变化上看,物种丰度呈现从上游至下游逐渐减少趋势。从时空变化的影响因素上看,非汛期总磷和电导率影响最大,其解释度分别为：10.96%和8.36%;汛期总磷、总氮和氨氮影响最大,其解释度分别为9.47%、8.08%和6.96%。 相似文献
3.
辽河流域生态需水估算 总被引：13，自引：0，他引：13
从辽河流域存在的环境问题出发,在确定主要生态需水类型的基础上,基于水资源分区,分别估算各水资源分区的不同类型的生态需水,包括枯季河道生态需水、汛期输沙需水、入海需水、地下水恢复需补充的水量、河口湿地生态需水等。针对辽河流域季节性河流的特点,提出了枯水季节最小流量法的枯季河道生态需水计算方法。计算结果表明,辽河流域生态需水总量为130.44×108m3,占地表径流的48.3%,其中浑太河、东辽河2个水资源分区的生态需水量占地表径流的比例在60%以上,辽河干流生态需水量占地表径流的53.5%,其余水资源分区生态需水量占地表径流的比例均在50%以下。研究结果为流域水资源配置及水环境保护与恢复提供科学依据。 相似文献
4.
南京城市湖泊湿地的水质动态及其评价 总被引：4，自引：1，他引：3
选取南京市玄武湖、莫愁湖、内秦淮河湿地为对象,通过定点、定时采样和水质分析等方法,对城市湖泊湿地水质的季节动态、水质影响因素及其富营养化评价等进行了研究。结果表明,TN、TP、BOD和COD是反映城市湖泊水体污染度的重要指标,TP含量过高是造成城市河湖湿地水体富营养化的主要原因。水体污染程度随季节动态表现为:夏季>春季>秋季>冬季。相对封闭的莫愁湖湿地水质的季节变化较小,但水质较差,各个季节均表现出重富营养化—严重富营养化状态;受工业或生活污水影响较大的内秦淮河湿地,水体受污染严重,全年均属严重富营养—异常富营养化;玄武湖湿地的水体,在春季和秋季均已达到富营养化水平,夏季相对较好,TN、TP为富营养化水平,其余指标为中—富营养水平。 相似文献
5.
为探究西北干旱区内陆河流域水生态系统时空演变规律,2017年7月对黑河甘肃段进行了浮游植物的采样调查,并收集1981、1997、2008年浮游植物夏季调查数据,分析黑河上中下游浮游植物物种、生物多样性和优势种等群落结构的演变特征,同时提出生物活动力指标以表征河流生物的活动能力和活跃程度。结果表明：在空间分布上,黑河中游在各年份都具有最为丰富稳定的浮游植物群落结构,物种数（61属）、生物多样性指数（2.87）和生物活动力指数（0.194万cells·hm-2）均高于上下游。在时间尺度上,上游浮游植物群落变得持续丰富;中游从1981年持续衰落到2008年后出现反转并快速恢复到2017年更为丰富和活跃的水平;下游则呈现出持续衰落的态势。以1981年为基准,黑河中游水域面积到2010年减小5.2%,浮游植物生物活动力降低了16.5%,到2017年水域面积增加1.2%,浮游植物生物活动力增加了4.3%。黑河浮游植物对流域天然湿地及水域的变化具有强烈的敏感性和依赖性,浮游植物演变特征与湿地水域面积变化趋势一致。 相似文献
6.
This paper examines the use of fossil larval trichopteran communities to investigate and describe the flow environment of
a paleochannel network in the middle reaches of the River Trent floodplain (UK). Previous research utilising fossil insect
communities (principally O. Coleoptera, O. Chironomidae) has focussed upon climate reconstruction. However, larval trichopteran
communities (O. Trichoptera) also offer an aquatic signal, giving information regarding channel habitat structure and flow
environments. The taxonomic diversity of each fossil community and the categorisation of each taxon into a known flow group,
using the “LIFE” methodology, facilitates the reconstruction of the river flow conditions at each site based upon known faunal
associations with mean flow velocity. A total of 49 trichopteran taxa were recorded from 17 paleochannels (n = 170 samples). Detrended Correspondence Analysis (DCA) identified a environmental gradient on the first DCA axis that reflected
variability in flow, from rapid/fast flow to slow flowing and standing water habitats. In addition, two distinct faunal groups
were identified on the second DCA axis characteristic of (i) small nutrient rich lentic habitats; and (ii) larger water bodies
displaying features of both lentic, lotic and ephemeral habitats where marginal vegetation is abundant on a mineral substratum.
The results demonstrate that larval Trichoptera can be used in paleolimnological research to reconstruct a flow signal and
provide additional information regarding the aquatic habitat structure. Their wider use in describing the aquatic environment,
in association with other proxies (e.g., Chironomidae and Coleoptera), may provide a more holistic understanding of floodplain
paleoenvironment succession. 相似文献
7.
景观空间异质性对地表水质服务的影响研究——以河南省伊河流域为例 总被引：1，自引：1，他引：0
人类干扰使景观空间异质性发生了剧烈变化,进而对生态系统服务产生了严重影响。目前,针对景观空间异质性与生态系统服务的关联关系研究还较为薄弱。以河南省伊河流域为研究区域,以地表水质服务为研究对象,分析了地表水质服务的空间变化;通过以水质采样点为中心建立缓冲区,分析了不同尺度下的景观空间异质性特征,并与地表水质指标进行相关性研究,以探讨景观空间异质性与地表水质服务间的影响规律及响应机制。结果表明：① 研究区地表水质状况整体上为西南、东北部较差,中部较好;② 从景观组成来看,林地面积占比或斑块个数的增加有利于地表水质的提高;③ 类型水平上,林地的景观构型与化学需氧量的质量浓度在200 m半径缓冲区内显著相关（P<0.05）,城镇用地的景观构型对地表水质的影响则在2000 m半径缓冲区内更为明显;④ 景观水平上,总磷的质量浓度受到景观构型变化的强烈影响（P<0.05）,景观构型异质性越低,总磷的质量浓度就越高;⑤ 适当增加景观空间异质性可有效降低地表水质污染物的质量浓度,提高地表水质服务。研究结论可为伊河流域的空间开发及水环境保护政策的制定提供科学依据。 相似文献
8.
Yu-Xin Fan Fa-Hu Chen Guo-Xiao Wei David B. Madsen Charles G. Oviatt Hui Zhao Xi Chun Li-Ping Yang Tian-Lai Fan Guo-Qiang Li 《Journal of Paleolimnology》2010,43(3):577-587
Lake Jilantai-Hetao, a megalake, was formed some time before 60–50 ka, along the Great North Bend of the Yellow River. The
basin is now dry, with most of the area covered by aeolian sand. We are investigating this profound hydrologic change using
a number of research approaches. Paleoshorelines of this megalake are best preserved in the Jilantai area in the southwestern
portion of the megalake basin. We collected aquatic mollusk shells from littoral sediments at different altitudes around Jilantai
and measured their strontium isotope compositions. 87Sr/86Sr ratios in shell carbonates are different between the high lake phase (~1,080–1,050 m altitude) and the low lake phase (~1,044–1,030 m
altitude), with a small shift in average strontium ratios to more radiogenic values during the low lake phase. Based on regional
hydrology and physical geography, we conclude that water from the Yellow River was the dominant water source supplying this
megalake. 87Sr/86Sr ratios of modern water samples suggest the Yellow River was the dominant water source during the high lake phase, but that
the relative contribution of Yellow River water to the megalake was reduced, and that the relative contributions of local
precipitation and groundwater increased, during the low lake phase. 相似文献
9.
图们江地区水环境质量研究 总被引：7，自引：3，他引：7
图们江地区５条河流１８个断面水环境质量研究表明，本区地表水污染比较严重，大部分河流断面水质在Ⅳ、Ⅴ级水平，只有珲春河水质优于Ⅲ级，除布乐哈通河水质继续呈下降趋势外，其它河流污染水平基本得到了控制，河流污染物比较固定，主要是ＳＳ、ＣＯＤ、ＢＯＤ、ＡＲ－ＯＨ、Ｎ－ＮＨａ。 相似文献
10.
Ben J. Kefford 《International Journal of Salt Lake Research》1998,7(4):285-299
The effect of saline lake water disposal from the Lough Calvert Drainage Scheme on water quality of the Barwon River, in south
west Victoria, Australia, was investigated. The Scheme is used to regulate the levels of several saline lakes outside the
Barwon's catchment. This study found that the disposal of saline lake water was associated with increased total phosphorus,
PO4, TKN, suspended solids, electrical conductivity and stream discharge and lower NOx in the Barwon River. Thus, when disposing
of saline water, factors other than salinity should be considered in order to prevent an impact on the aquatic environment.
At present this is generally not done. The results are discussed with reference to the effects of saline water disposal on
aquatic biota and how the effect of saline lake water disposal on water quality may differ from the disposal of saline groundwater. 相似文献
11.
基于水环境承载力的沁河流域系统优化调控 总被引：8，自引：1，他引：7
基于水环境承载力核算模型,提出流域系统优化调控方法,并应用于沁河流域。通过承载力核算模型计算出2015年和2020年流域水环境承载力,当系统动力学预测的2015年和2020年经济发展规模高于承载力时,通过约束条件中工业企业排放浓度、城镇生活污水收集率、水资源利用率、尾水回用率等4项调控指标进行敏感度分析,最终确定最优的经济发展。结果表明:沁河流域应该优先调控城镇生活污水收集率;2015年,执行工业污水排放二级标准,收集率须达到71.4%以上,优化后的经济规模阈值为475.6亿元;2020年,执行工业一级标准,城镇生活污水收集率须为78.4%以上,相应地经济规模阈值为816.0亿元。 相似文献
12.
根据非恒定流运动的圣维南方程组,以及污染物浓度变化的一维带源项对流扩散方程,建立了闽江下游河道一维动态水动力水质模型,率定了糙率、纵向离散系数和污染物降解系数,验证了模型的合理性.计算结果表明,模型下边界定在梅花断面,为研究包括福州段在内的马尾(白岩潭)以上河段的水环境问题提供了适当的条件;河道来水污染负荷总量、流量和浓度条件对南、北港水质影响显著. 相似文献
13.
H. Cremer F. P. M. Bunnik T. H. Donders W. Z. Hoek M. Koolen-Eekhout H. H. Koolmees E. Lavooi 《Journal of Paleolimnology》2010,44(3):789-801
A 400-year sediment record from an 18 m deep scour hole lake (Haarsteegse Wiel) near the Meuse River in the Netherlands was
investigated for past changes in water quality, flooding frequency and landscape change using geophysical, geochemical and
micropaleontological information. The results are highly significant for determining long-term trends of water quality, the
impact of atmospheric (as SCP, spheroidal carbonaceous particles) and industrial (chromium) pollution on the terrestrial and
aquatic flora, and the impact of river floods. The studied sediment record was dated by combining 137Cs activities, biostratigraphical ages, micro-tephra layers, and historically documented floods indicated by the magnetic
susceptibility. The oldest flooding event is indicated at AD 1610 when the lake was created by water masses bursting through
a dike. Large historical river floods are well documented in regional chronicles and thus may provide reliable age calibration
points. Based on assumptions about the timing of flood events and constant rate of sedimentation, it appears that sedimentation
rates in Haarsteegse Wiel declined after ca. AD 1880. This decline might be a result of a widespread change from wheat cultivation
to pasture land from around AD 1875 as a direct result of falling wheat prices and intensified cattle farming linked to the
agricultural crisis in the last quarter of the nineteenth century. Water quality changes and absolute phosphorus concentrations
were reconstructed using a diatom-based transfer function. Results show that the currently nutrient-rich lake has mostly been
in a mesotrophic state prior to ca. AD 1920, with the exception of several apparently sharp eutrophication events that were
coeval with river floods. River flooding also impacted the vegetation composition by importing allochthonous components, and
indirectly by the influx of nutrients which had a clear influence on the composition of the water plant communities and aquatic
species diversity. Magnetic susceptibility changes and pollen data show that within the period AD 1610–1740, within the Little
Ice Age period, several undocumented floods may have occurred. Thus, documentation of geophysical, geochemical, and biological
flooding signals in a high-resolution archive present the possibility to detect flooding regimes further back in time. 相似文献
14.
辽河流域社会经济活动的COD污染负荷 总被引：6，自引：1，他引：5
辽河流域污染物的输入是辽东湾海洋环境变化的最主要原因,治理海洋污染的根本在于治理陆域污染。以辽河流域COD污染为研究对象,在社会经济数据空间化及与土地利用数据匹配的基础上剔除了部分无效数据,提高了流域污染物估算和空间分析的精度,估算结果表明:2010年辽河流域COD总污染负荷约101万t,其中居民生活和畜禽养殖排放合计占总污染负荷的80%,是流域COD污染的主要来源;工业源污染占11%;城市径流污染占9%。COD污染主要分布在辽河平原,且以面源污染为主,约有30万t入河。生物体代谢是COD污染的主要来源,污染物排放总量难于降低,辽河流域的COD污染压力短期内依然严峻。 相似文献
15.
对鄱阳湖目前存在的问题、控湖后可产生的效益和解决控湖工程难题的途径作了一些思考，建议尽快筑坝控湖以提高湖泊效益。 相似文献
16.
太湖流域水生态功能三级分区 总被引：8，自引：0，他引：8
水生态功能分区是进行流域现代水生态管理的必然要求,是面向水质目标管理控制单元划分的基础。针对太湖流域特征,提出了太湖流域水生态功能三级分区的目的和划分原则,在其指导下构建了太湖流域非太湖湖体区和太湖湖体区水生态功能三级分区指标体系;在GIS技术支撑下,分别以太湖流域非太湖湖体区1100多个和太湖湖体区3500多个水生态功能单元为基本空间统计单位,结合分区指标数据,制作了基于水生态功能单元的各项指标的空间分布图,采用二阶聚类法并结合人工辅助的方法将太湖流域划分为21个水生态功能三级区;分区水生态特征分析结果表明全流域各分区水生生物特征均具有较大的变异性,反映出流域内水生态的空间差异和不均匀性,体现了分区结果的合理性、科学性和可靠性。 相似文献
17.
科罗拉多河的适应性管理处于世界领先水平。美国为研究格伦峡谷大坝对下游水生生态系统的影响而进行了3次高速水流实验,取得了显著的生态效益,也积累了许多宝贵经验。分析显示,利益相关方参与是该实验成功的体制保障,跟踪监测与评估是实验成功的技术保障,闸坝适应性调度是河流保护与管理的有效手段。该实验的实施过程和效果对我国闸坝调度有许多有益的启示。例如,对下游水生生物和湿地生态系统的保护应作为闸坝调度的目标之一,应加强闸坝适应性调度的实验和研究,促进利益相关方参与河流保护与管理。 相似文献
18.
随着气候变化、人口增长和经济发展,全球水资源供需矛盾日益突出,国际河流跨境水冲突不断加剧。地处中东的约旦河是世界上跨境水冲突最严重的河流。1948—2008年约旦河跨境水冲突事件数量占全球总量的1/5,战争性跨境水冲突数量占同级别总量的2/3。本文以地缘价值、地缘关系和地缘结构为模块构建国际河流跨境水冲突地缘环境分析框架,考察约旦河跨境水冲突事件的时空演化及其形成的地缘机制。研究发现,约旦河跨境水冲突的地缘目标集中于水资源战略要地,且按水资源地“主要→核心→次要”空间转移;跨境水冲突事件在时序上呈现从以色列争夺水权为主向域内阿拉伯国家讨还水权为主演化;跨境水冲突地缘体结构中以色列主动发起的跨境水冲突占六成多,域内阿拉伯国家和域外地缘体发起的各约占二成。基于地缘环境分析框架的研究得出以下结论：约旦河流域区位的地缘价值吸引域外大国直接介入,促成跨境水冲突向有利于美国—以色列利益的方向发展;域内地缘体的“水资源地”竞争地缘关系强于“水量”竞争地缘关系,对约旦河跨境水冲突具有强化作用;以色列作为约旦河地缘结构中的水霸权,对该流域跨境水冲突的基本态势和时空分布格局具有主导作用。 相似文献
19.
Hydrological exchange and subsurface water chemistry in streams varying in salinity in south-western Australia 总被引：1，自引：0，他引：1
Many streams in Westrn Australia are naturally saline. In others, especially in the south-western corner, land-clearance and
other human activities in the catchment have accelerated rates of salinisation of surface and groundwater. Trends in surface
water salinity are well-documented but the extent of penetration of saline stream water into the sediments has been little
studied. As many of these streams have porous sandy beds and their flows may derive from groundwater, hydrologic exchange
patterns between surface water and subsurface hyporheic water were hypothesised to govern the water chemistry of such rivers.
We predicted high rates of hydraulic conductivity, leading to a close relationship between surface and subsurface (to a depth
of 50 cm) salinity, and to a lesser extent, pH and dissolved oxygen. Where surface and hyporheic water differed in salinity,
other chemical differences were hypothesised to be similarly marked, perhaps resulting from disjunct shallow subsurface aquifers.
Triplicate wells were sampled from upwelling and downwelling zones of thirteen streams ranging in salinity from ca. 0.2 to
18 g L−1. Despite the seemingly-porous sandy beds at many sites, subsurface water chemistry only 20–40 cm below the bed sometimes
differed markedly from surface water. For example, hyporheic water was only one-fifth the salinity of surface water at some
saline sites (e.g., the Tone River) or 20 per cent more saline in streams with fresh surface water (e.g., the Weld River).
At some sites of intermediate salinity (e.g., the Warren River), subsurface water was up to three times fresher than surface
or downwelling water. Percentage saturation of dissolved oxygen in the hyporheic water was consistently low (<40%) whereas
pH was more acidic than surface water, presumably due to microbial activity. Vertical hydraulic conductivity may be limited
by layers of fine sediments and clays, implying that the meso-scale (1–100 cm) hydrological dynamics within the hyporheic
zones of these rivers are more complex than their sandy beds would indicate. Assumptions of ecosystem dynamics in saline streams
must be tempered by an understanding of hyporheic salinities as subsurface fresher water may support microbial and faunal
assemblages excluded from the surface benthos by high salinity. In saline streams, as in fresh ones, the hyporheic zone is
an important component of the stream ecosystem and equally prone to disruption by human activities. 相似文献
20.
Chee Kong Yap Ahmad Ismail Ching How Low Soon Guan Tan 《湿地科学》2007,5(4):311-321
Three different aquatic ecosystems(an urban pond,Kelana Jaya Pond;a polluted river,Sepang River;and the intertidal and offshore areas of the west coast of Peninsular Malaysia)with different sets of ecological backgrounds and human activities were reviewed and assessed for the levels of Cu and Zn contamination with special reference to those found in polluted sediments collected from the Sepang River.The discussion on the contamination levels of Cu and Zn in the aquatic environment of Peninsular Malaysia was based on a comparison of the metal contamination of 4 kinds of aquatic environments.The comparison of 4 different areas was based on ① total concentrations of 2 metals;② the concentrations and percentages of the nonresistant(EFLE,acid-reducible and oxidisable-organic)and resistant geochemical fractions;and ③ correlation coefficients(R-values)based on data of 4 areas separately and a combination of 4 areas.The Sepang River recorded nonresistant fractions of 63.1% for Zn and 55.8% for Cu in addition to slightly lower metal concentrations when compared to those(60%-70%)reported before the shutting down of the piggery activities in that area.These nonresistant metal percentages(55%-63%)indicated that the metal concentrations were still dominated by anthropogenic sources since nonresistant fraction of metals were mostly contributed by anthropogenic sources.The positive results from the four different aquatic environments assessed here provided strong evidence to show that Malaysia's aquatic environment had received anthropogenic Cu and Zn.The present study also showed that the percentage of the nonresistant fraction and the R-values based on correlation analysis of Cu and Zn could be used as indicators of Cu and Zn pollution in the Malaysian aquatic ecosystem.Based on the present data,the correlation coefficients(R-values)are potential indicators of EFLE Cu and acid-reducible Cu of the sediments.The use of R-values as indicators of metal pollution is suggested and it is applicable to other heavy metal data although it should be improved in future studies. 相似文献