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1.
Degraded streams have been shown to retain fewer nutrients than un‐modified streams. The aim of this project was to investigate the relative importance of abiotic and biotic pathways of phosphorus uptake by epilithic communities in un‐modified and modified streams. This was investigated through a series of filterable reactive phosphorus (FRP)‐uptake experiments in two streams of the Torrens River Catchment, South Australia. Total benthic FRP uptake was assessed as the loss of FRP to un‐sterilized epilithic communities (kT), abiotic uptake was the loss to sterilized epilithic communities (kA) and biotic uptake (kB) was the difference between total and abiotic uptake. It was hypothesized that un‐modified reaches would have higher kA and kB than degraded and engineered reaches. Overall, kT, kA and kB were greatest in un‐modified reaches, but this pattern was not consistent across seasons. kT and kB were greatest in the un‐modified reaches in autumn–winter and late spring, but not in winter–spring. Differences in kB were best explained by phosphorus availability in the water column and the period of continuous flow. kA was greatest in the un‐modified reaches in autumn–winter, greatest in the degraded reaches in winter–spring, but similar in the un‐modified reaches and degraded reaches in late spring. kA was most dependent upon the background FRP concentration, but also the attached organic matter in the un‐modified reaches. The project demonstrated that several impacts of changes in land‐use can alter the affinity of biotic and abiotic processes for phosphorus, which will have implications for in‐stream nutrient availability and downstream ecosystems. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
2.
《Journal of Contemporary Water Research & Education》2017,160(1):100-118
Anthropogenic inputs of nutrients threaten water quality around the world, causing eutrophication and altering phytoplankton communities. In freshwater systems, certain physiochemical conditions, including high TP, low TN:TP, and warm temperatures, can lead to problematic cyanobacteria blooms. Cyanobacteria can decrease phytoplankton diversity and phytoplankton diversity has been positively linked to zooplankton diversity, suggesting that cyanobacteria may have indirect negative effects on zooplankton diversity. Using monitoring data from Lake Champlain, we tested three hypotheses: (1) cyanobacteria density and phytoplankton diversity are inversely related; (2) phytoplankton diversity and zooplankton diversity are positively related; and by extension (3) cyanobacteria density and zooplankton diversity are inversely related. Relationships were investigated separately at shallow (4–15 m) and deep (25–100 m) sites using several diversity metrics. At deep sites, cyanobacteria density was only related (positively) to zooplankton Shannon diversity. At shallow sites, all three hypotheses were supported by three of four diversity metrics; low phytoplankton richness appears to be the link between high cyanobacteria density and low zooplankton diversity. Our results suggest that cyanobacteria may indirectly reduce zooplankton diversity by decreasing resource heterogeneity, although our results based on observational data were also consistent with well‐known direct pathways. Because low biodiversity can alter ecosystem processes and impair functioning, our results suggest that shallow systems may be more responsive to global change than deeper systems. 相似文献
3.
Water is one of the most important ecosystem services because it is essential for food and energy production. The Tungabhadra basin, located in peninsular India, has a variety of challenges, including inter-basin water-sharing issues, low agricultural productivity and value, and rising need for renewable energy production. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) water yield model is used to analyze the consequences of climate change on water related services such as water yield and hydropower generation in the densely populated Tungabhadra basin. The impact of climate change on water supply services is studied for the period 1971–2000 as well as the future period 2021–2040. The model is calibrated using streamflow data collected at the Bawapuram gauge station in Telangana and there is a strong correlation between observed and simulated flow. The water yield for the entire basin declined by 33 and 50% under the Representative Concentration Pathways (RCP) 4.5 and 8.5 scenarios, respectively. The RCP 4.5 scenario reduces hydropower production and its Net Present Value (NPV) by 41 to 59%, whereas the RCP 8.5 scenario reduces production and NPV by 56 to 67%. The assessment of ecosystem services at the catchment scale revealed that the basin could be vulnerable to climate change due to a dramatic drop in ecosystem services. The methodology developed in this study can be applied to other river basins where quantifying ecosystem services is critical. 相似文献
4.
This Perspective argues for an expansion of conventional concepts of river biomes to better encapsulate the emerging social understanding of ‘biomes’ as living systems with unique macro- and micro-biotic ecological and biological signatures. We approach this by firstly examining recent interpretations of river biomes that have evolved from original zonal conceptions. We then postulate on the social/public understanding on ‘biomes’ through the popularity of two rich debates: human health via gut microbiomes and soil health via the soil microbiome. With these concepts in mind, we define the river biome as ‘A living flowing aquatic ecosystem, indicative of its environmental context, comprising unique biological, ecological, hydrologic and health characteristics that shape and are shaped by macro- and micro-biotic signatures and functions’. With this definition the term river biome is more aligned with ideas of river health and ecosystem functioning, which we believe may evoke greater public understanding of rivers as complex living systems. Enhanced public understanding of complex natural systems should be encouraged as a means by which to propel policy, funding and research as well as to improve specialist to non-specialist communication and relations. 相似文献
5.
Richard E. Brazier Alan Puttock Hugh A. Graham Roger E. Auster Kye H. Davies Chryssa M. L. Brown 《Wiley Interdisciplinary Reviews: Water》2021,8(1)
Beavers have the ability to modify ecosystems profoundly to meet their ecological needs, with significant associated hydrological, geomorphological, ecological, and societal impacts. To bring together understanding of the role that beavers may play in the management of water resources, freshwater, and terrestrial ecosystems, this article reviews the state‐of‐the‐art scientific understanding of the beaver as the quintessential ecosystem engineer. This review has a European focus but examines key research considering both Castor fiber—the Eurasian beaver and Castor canadensis—its North American counterpart. In recent decades species reintroductions across Europe, concurrent with natural expansion of refugia populations has led to the return of C. fiber to much of its European range with recent reviews estimating that the C. fiber population in Europe numbers over 1.5 million individuals. As such, there is an increasing need for understanding of the impacts of beaver in intensively populated and managed, contemporary European landscapes. This review summarizes how beaver impact: (a) ecosystem structure and geomorphology, (b) hydrology and water resources, (c) water quality, (d) freshwater ecology, and (e) humans and society. It concludes by examining future considerations that may need to be resolved as beavers further expand in the northern hemisphere with an emphasis upon the ecosystem services that they can provide and the associated management that will be necessary to maximize the benefits and minimize conflicts. This article is categorized under:
- Water and Life > Nature of Freshwater Ecosystems
6.
Matteo Roncoroni Jade Brandani Tom I. Battin Stuart N. Lane 《Wiley Interdisciplinary Reviews: Water》2019,6(6)
The term “ecosystem engineering” emerged in the 1990s and is commonly used to refer to the activities of larger organisms like beavers and trees in rivers and streams. The focus on larger organisms may be motivated by their more visible effects on the environment. However, while it may be intuitive to suggest that the bigger the organism the bigger its potential engineering effects, there may be microscale organisms who through their number rather than their size can act simultaneously to result in significant impacts. This paper considers biofilms as a candidate ecosystem engineer. It is well known that biofilms play an important role in enriching the sediment matrix of nutrients and in stabilizing sediments. Biofilms may be critical in increasing the habitability of the benthic substratum. In this paper, we consider their potential role in the ontogeny of ecosystems in recently deglaciated terrain. We show how by changing sediment stoichiometry, decreasing sediment erodibility, and reducing surface sediment permeability they may promote primary succession on lateral, incised terraces, which are less perturbed compared with the main active floodplain. This article is categorized under:
- Water and Life > Nature of Freshwater Ecosystems
- Science of Water > Water and Environmental Change
7.
青海湖生态环境演变与稳定性 总被引：1，自引：0，他引：1
根据长系列水文模型模拟结果,对青海湖的环境演变进行了分析,利用一阶周期性自回归模型对青海湖水位变化趋势及其对湖泊生态的影响进行了预测。结果表明:青海湖多年平均亏缺水量为3.31亿m3,近10 a来增温幅度较大时期的亏缺水量为5.19亿m3;保持青海湖生态稳定的关键物种为青海湖裸鲤,盐度是决定青海湖裸鲤繁殖和生长的关键环境要素,其阈值为16.8‰;考虑气候变化的影响时,青海湖水位在未来30 a会继续下降,水位阈值为3 190.25 m,2030年水位最低,为3 191.35 m,此后水位开始小幅度回升并逐渐趋稳;不考虑气候变化的影响时,预计未来30 a内青海湖水位仍会持续下降,之后下降趋势开始变缓并趋于稳定,2100年左右稳定在3 192.25 m;两种预测结果都没有下降到青海湖生态稳定的水位阈值,因此未来青海湖生态系统的稳定性不受影响。 相似文献
8.
茎流是大气降水与溶解物在植物茎干上的汇集与运移,它对森林和农业生态系统具有重要的水文学和生态意义。本文总结了前人研究成果,加深了对茎流的理解并找出缺陷与误区,以促进对薄弱环节的研究。探讨了气象条件,季节变化,覆被结构,冠层空间型及植被种别等多个复杂易变因素对茎流量和其化学成分的影响。 相似文献
9.
Leaf litter decomposition is an important process providing energy to freshwater biota. Flow regulation and dams can strongly alter freshwater ecosystems, but little is known about the effect of small impoundments on leaf litter decomposition rates in headwater streams. In this study, we examined the effect of small water storage impoundments (80 to 720 m3) on leaf litter decomposition by comparing sites located within 10‐m upstream and downstream of nine impoundments (Rhineland Palatinate, Germany) and sites located further upstream and downstream. The impoundments did not have a statistically significant effect on most physico‐chemical variables. However, the abundance of shredders and leaf litter decomposition rates decreased in study sites located within 10‐m upstream of the area flooded by impoundments. Small impoundments can locally reduce leaf litter decomposition rates in headwater streams. The effect of small impoundments on ecosystem functioning is minor and may require less attention by freshwater managers than other stressors, though this may differ for other ecological aspects such as connectivity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
10.
芮孝芳 《水利水电科技进展》2018,38(6):1-7
讨论了水文实验客观上的局限性及进一步发展的困难,论述了提升水文观测技术和方法的重要性及重点发展的若干方面。在分析科学研究数据密集范式产生背景及其强大生命力的基础上,指出水文学研究适合应用数据密集范式的理由,并提出了初步设想。呼吁水文学家应抓住机遇,在大力、深入发展水文遥感的同时,将发展数据水文学提上议事日程,摆到重要位置。展望未来,水文学将是在数据密集范式驱动下,物理水文学、随机水文学、仿真水文学和数据水文学相互补充、融合发展的水文学。 相似文献
11.
The hydrologic regime of the Illinois River has been altered over the past 100 years. Locks and dams regulate water surface elevations and flow, enabling commercial navigation to continue year round. This study relates changes in water surface elevation to fish abundance in the river, and establishes target criteria for operating locks and dams. Using long‐term records of daily river stage, we identified ecologically meaningful hydrological parameters for eight gage locations along the Illinois River. Inter‐annual variability of a long‐term fisheries dataset beginning in 1957 was related to variability in stage, flood and recession duration, frequency, timing, and rate of change of water levels. Reversals in water surface elevation, maximum stage levels, and length of the spring flood were the most important parameters influencing abundance of age‐zero fishes in annual collections. Smallmouth buffalo (Ictiobus bubalus), black crappie (Pomoxis nigromaculatus), freshwater drum (Aplodinotus grunneins), and white bass (Morone chrysops) were most abundant in samples during years that approximated the natural water level regime. Of the 33 hydrologic parameters evaluated for the entire water year from an Illinois River gage site on La Grange Reach, all except average stage in January and Julian date (JD) of maximum stage had moderate or high hydrologic alteration based on the historical range of variation (RVA). The highest degree of hydrologic alteration was for minimum stage levels (1‐day, 3‐day, and 7‐day), rate‐of‐rise, and rate‐of‐fall. Other parameters that have been severely altered were 30‐day minimum stage, 90‐day maximum stage, and the annual number of water level reversals. Operations of the La Grange and Peoria locks and dams could be modified so water level variability would approximate that of the late 1800s, when fish and wildlife resources were abundant. The water regime could be regulated to maintain navigation and improve conditions for native plants and animals without increasing flood damages. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
12.
Natural hydrogeomorphic characteristics and hydrologic alterations are important ecological drivers, and hydrology is also a common ecological, flood control and navigation system indicator. Hydrologic characteristics change dramatically from one end of the Upper Mississippi River System to the other, and hydraulic characteristics also differ spatially across the river channels and floodplain in response to dams, levees and diversions. Low flow surface water spatial change in response to navigation and flood control has been well known for many years, but little information was available on the spatial distribution of frequent floods. The flow frequency data presented here were developed to better estimate contemporary floods after historic flooding in 1993. Flood stage estimates are enhanced in GIS to help quantify and map potential floodplain inundation for more than 1000 river miles on the Upper Mississippi and Illinois Rivers. Potential flood inundation is mapped for the 50% to 0.2% annual exceedance probability flood stage (i.e. 2‐ to 500‐year expected recurrence interval flood) and also for alternative floodplain management scenarios within the existing flood protection infrastructure. Our analysis documents: (i) impoundment effects, (ii) a hydrologic gradient within the navigation pools that creates repeating patterns of riverine, backwater and impounded aquatic habitat conditions, (iii) potential floodplain inundation patterns for over 2 million acres and (iv) several integrated floodplain management scenarios. Extreme flood events are more common in recent decades, and they are expected to continue to occur at greater frequency in response to climate change. Floodplain managers can use the results presented here to help optimize land management and flood damage reduction on the Upper Mississippi River System. Published 2012. This article is a U.S. Government work and is in the public domain in the USA. 相似文献
13.
Steven J. Guldan Alexander G. Fernald Carlos G. Ochoa Vincent C. Tidwell 《Journal of Contemporary Water Research & Education》2013,152(1):49-54
In New Mexico, increasing demand for water, combined with limited supplies and periodic drought, is placing additional stress on traditional acequia communities. Research on the hydrology of acequia agriculture in northern New Mexico has been carried out in three communities and their associated watersheds and irrigated valleys. Critical to the effort has been the participation of the acequias and individual farmers, ranchers, and other community member stakeholders. Participation in hydrology research included assistance in altering flows in acequias, and access to private property and wells, critical to obtain ground and surface water measurements. Further research that integrated hydrologic data with ecosystem, land‐use, economics, and sociocultural data, via development of a system dynamics model, required community member participation through surveys, interviews, and workshops to develop, calibrate and refine the model. 相似文献
14.
黄河源区水文气象要素变化对生态环境的影响 总被引：6，自引：0，他引：6
根据黄河源头地区的降水、蒸发、径流等水文气象要素多年变化资料,并结合20世纪70～90年代的卫星影像资料的分析,认为气候变化和人类活动等因素极大地改变了黄河源头地区生态环境的格局,是影响黄河源头生态环境的主要因素。 相似文献
15.
针对内陆干旱区城市发展和生态环境保护的强烈互斥性,在整体识别内陆干旱区水循环与生态演变耦合作用机理上,构建基于生态水文阈值调控的水资源多维均衡配置模型。模型分3个层次:以流域为单元的水资源系统耗水总量和地下水采补平衡;以行政分区为单元的经济社会系统水量平衡和水土平衡;以河道关键控制断面和灌区为单元的生态环境系统水生态平衡和水盐平衡,并给出相应的多重循环迭代算法。将该模型方法应用于我国内陆干旱区——塔里木河流域,结果显示:在平枯水平年通过累计新增节水灌溉面积85.1万hm~2,累计退减基本农田外灌溉面积41.5万hm~2,累计退减国民经济用水量为75亿m~3,可实现该地区水资源-经济社会-生态环境复合系统的有序良性演化和高效均衡发展,验证了该方法的可行性。 相似文献
16.
从人类活动影响水文测验谈贯彻水文条例 总被引：2，自引：0，他引：2
人类活动对水文实测数据序列的一致性产生了很大影响,人类活动干扰水文测验事件愈演愈烈。结合陕西省宣传贯彻水文条例取得的初步成效,提出了各地出台配套规章制度、实施大水文战略、机构升格、加强自身建设等建议。 相似文献
17.
低浓度基质下厌氧氨氧化反应器的启动及其运行性能 总被引：1，自引：0，他引：1
在低浓度基质条件下进行厌氧氨氧化反应器(ANAMMOX)的启动试验,先培养好氧硝化生物膜,然后转向厌氧环境培养厌氧氨氧化菌,经过294天成功启动反应器.在ANAMMOX稳定运行期,NH3-N的去除量:NO-2-N的去除量:NO-3-N的生成量为1:1.38:0.4.反应器的脱氮性能随着进水TN负荷的增加而提高,氮素去除负荷最高达到0.431 kg/(m3·d),并与进水TN负荷呈现良好的相关性.在上向流反应器中,NH3-N、NO-2-N浓度随水流沿滤柱高度不断降低,同时生成NO-3-N.沿水流方向至滤柱高120 cm处NH3-N和NO-2-N的去除率分别达到86.7%和近99%,TN的去除率达到85.4%.CODCr也随水流不断下降,pH则沿程上升. 相似文献
18.
基于MODIS卫星遥感数据,计算了云南省2000—2014年陆地生态系统水分利用效率(WUE),结合国家气象站点的观测数据,采用趋势分析、EOF分析和相关性分析等方法,获取了云南省陆地生态系统WUE时空变化规律和主要驱动因子。结果表明:云南省陆地生态系统WUE空间分布差异明显,呈现南北低、中间高的格局,WUE在大部分地区呈现了明显的季节变化,而在低值区变化不显著;WUE年际变化趋势存在明显的南北差异,北方主要呈增加的趋势,南方主要呈减少的趋势,蒸散发是其变化的主导因素;WUE空间模态呈现南北反向分布模式,北方增加,南方减少,反之亦然;WUE驱动因子自北向南依次为相对湿度、最高温度和日照时数,相关关系呈现南北差异。 相似文献
19.
20.
信息化技术和手段为水文勘测工作的深化提供了基础和条件。通过对湖北省水文勘测工作现状和问题的分析,提出了改进水文勘测工作的思路。充分利用信息化平台,从站网建设、信息系统扩充、勘测技术研究、人才培养和优化管理方式等方面提出了建议。 相似文献