Constructing an Interdisciplinary Flow Regime Recommendation1

Bartholow, John M., 2010. Constructing an Interdisciplinary Flow Regime Recommendation. Journal of the American Water Resources Association (JAWRA) 1-15. DOI: 10.1111/j.1752-1688.2010.00461.x Abstract: It is generally agreed that river rehabilitation most often relies on restoring a more natural flow regime, but credibly defining the desired regime can be problematic. I combined four distinct methods to develop and refine month-by-month and event-based flow recommendations to protect and partially restore the ecological integrity of the Cache la Poudre River through Fort Collins, Colorado. A statistical hydrologic approach was used to summarize the river’s natural flow regime and set provisional monthly flow targets at levels that were historically exceeded 75% of the time. These preliminary monthly targets were supplemented using results from three Poudre-specific disciplinary studies. A substrate maintenance flow model was used to better define the high flows needed to flush accumulated sediment from the river’s channel and help sustain the riparian zone in this snowmelt-dominated river. A hydraulic/habitat model and a water temperature model were both used to better define the minimum flows necessary to maintain a thriving cool water fishery. The result is a range of recommended monthly flows and daily flow guidance illustrating the advantage of combining a wide range of available disciplinary information, supplemented by judgment based on ecological principles and a general understanding of river ecosystems, in a highly altered, working river.     

Modeling Streams and Hydrogeomorphic Attributes in Oregon From Digital and Field Data1

Abstract: Managers, regulators, and researchers of aquatic ecosystems are increasingly pressed to consider large areas. However, accurate stream maps with geo‐referenced attributes are uncommon over relevant spatial extents. Field inventories provide high‐quality data, particularly for habitat characteristics at fine spatial resolutions (e.g., large wood), but are costly and so cover relatively small areas. Recent availability of regional digital data and Geographic Information Systems software has advanced capabilities to delineate stream networks and estimate coarse‐resolution hydrogeomorphic attributes (e.g., gradient). A spatially comprehensive coverage results, but types of modeled outputs may be limited and their accuracy is typically unknown. Capitalizing on strengths in both field and regional digital data, we modeled a synthetic stream network and a variety of hydrogeomorphic attributes for the Oregon Coastal Province. The synthetic network, encompassing 96,000 km of stream, was derived from digital elevation data. We used high‐resolution but spatially restricted data from field inventories and streamflow gauges to evaluate, calibrate, and interpret hydrogeomorphic attributes modeled from digital elevation and precipitation data. The attributes we chose to model (drainage area, mean annual precipitation, mean annual flow, probability of perennial flow, channel gradient, active‐channel width and depth, valley‐floor width, valley‐width index, and valley constraint) have demonstrated value for stream research and management. For most of these attributes, field‐measured, and modeled values were highly correlated, yielding confidence in the modeled outputs. The modeled stream network and attributes have been used for a variety of purposes, including mapping riparian areas, identifying headwater streams likely to transport debris flows, and characterizing the potential of streams to provide high‐quality habitat for salmonids. Our framework and models can be adapted and applied to areas where the necessary field and digital data exist or can be obtained.     

Integral assessment of estrogenic potentials of sediment-associated samples

GOAL, SCOPE AND BACKGROUND: Exogenic endocrine-active substances are also called 'Endocrine Disrupting Chemicals' (EDC). They imitate or hinder the function of natural endogenic hormones or disturb the synthesis or the metabolism of hormones or of hormone receptors. The Enzyme-Linked Receptor Assay (ELRA) can detect estrogenic and anti-estrogenic effects at the level of receptor binding and is a useful tool for the integrative detection of contaminant effects. Although the test system has been used repeatedly in sediment assessments, the questions have remained concerning how it responds to variations in the physico-chemical matrix. For some bioassays, the salinity of the sample is a critical factor. This is especially relevant when testing wastewater samples or when sediment-associated samples in the tidal reaches of rivers are tested. Sediments in the tidal reaches of rivers change their salinity several times a day. Against this background, it would be beneficial to have a test procedure of known salinity tolerance. On account of this, the salinity tolerance of the ELRA was tested, assessed with reference substances at several salinity levels, and compared with the E-Screen method and a Yeast Estrogen Screen (YES), which are also frequently applied in environmental testing. The aim of this paper was to explore when the salinity limits within these test procedures are applicable. The trials should reveal the working range to be expected, characterize the salinity-dependent variations in sensitivity of the test, and provide options for methodological adjustments to improve the stability against increased salinity. METHODS: The ELRA was carried out with the human Estrogen Receptor alpha. (ER) using the same principle like a competitive immunoassay based on ligand-protein interaction. However, an essential difference is the use of a physiologically relevant receptor instead of an antibody as a linking protein. The ELRA measures the competition of sample estrogens and anti-estrogens against estradiol supplied as a BSA-coating conjugate for the binding site of dissolved ER. Estradiol or xeno-estrogen binding is quantified by a biotynilated anti-ER antibody and the subsequent measurement of peroxidase activity by a streptavidin-POD-biotin complex. The E-Screen was performed with the human breast cancer cell line MCF-7, which expresses the estrogen receptor constitutively. Cell proliferation depends on binding of estrogens or xeno-estrogens with the receptor. After incubation, estrogen-dependent cell growth was measured by sulforhodamin B staining. The YES was performed with a recombinant yeast strain, transfected with a receptor and a reporter plasmid bearing the estrogen receptor and a vitellogenin gene fused with the reporter gene lacZ. Estrogen or xeno-estrogen-dependent gene induction was measured indirectly by LacZ activity. The salinity levels were simulated in varying concentrations with NaCl from 0 to 40 per thousand or Artificial Sea Water (ASW) from 0 to 32 per thousand. RESULTS: The study characterized the factor 'salinity' for the prospective application fields of the ELRA. With reference substances such as 17-beta-estradiol, the ELRA showed classical sigmoidal concentration-effect relations in a range from 0.05 to 100 microg/l under physiological conditions. After a methodological adjustment to compensate decreasing receptor-binding affinity of estrogens and xeno-estrogens at higher salinity levels, the ELRA became applicable under salinity conditions up to concentrations of 20.5 per thousand. In tests, the ELRA reached under the influence of salinity a mean limit of detection of 0.062 microg/l 17-beta-estradiol. The mean relative inter-test error was around 11%. Above concentrations of 20.5 per thousand there is a risk of false negative assessment. Compared with the E-Screen method using the MCF7 cell line and the yeast estrogen test system (YES), the ELRA shows a lower sensitivity to 17-beta-estradiol. In the E-Screen, the cell proliferation was strongly reduced by sodium chloride induced cytotoxicity. In comparison with the E-Screen, the salinity tolerance of the YES and YAS methods is significantly higher. DISCUSSION: Despite adaption, total salinity tolerance could not be achieved with the ELRA. Freshwater samples were generally appraisable. Higher salinity levels above 20.5 per thousand would tend towards false negative results. The low inter-test error of 11% makes the ELRA suitable for the detection of estrogenic and anti-estrogenic potentials of single substances, substance mixtures, and of environmental samples. CONCLUSIONS: The ELRA is very fast and reproducible, it can be used for high-throughput screening in a microplate format at low cost, it is robust to microbial contamination, and is less susceptible to cytotoxic interferences than cell culture methods. RECOMMENDATIONS AND PERSPECTIVES: In their established form, the YES and the E-Screen methods are not applicable for liquid phase testing at higher salinity conditions. The salinity-adapted test version of the ELRA described here shows a broader working range for samples. Native water samples of more or less brackish origin or high-salinity effluent samples are testable. Results of tests with sediment associated samples of different salinity will be subject of a forthcoming publication.     

人工湿地中植物的修复作用原理与应用实例

植物修复在水污染防治中具有重要作用,有着广泛的应用前景。本文阐述了水生植物在湿地污水净化过程中的物理、化学、生物等方面的作用及原理,例举了植物修复在不同水质条件下的应用实例,提出应针对植物复氧能力、植物种类选择和收割植物后续处理等方面进行深入研究。     

水生生物对碳基纳米材料的物种敏感性分布研究

碳基纳米材料(CNMs)是科学研究中最热门的材料之一,然而CNMs对生态物种具有潜在的毒害作用.为了评估CNMs对生态物种的生态风险,通过广泛查阅,整理与分析了5种CNMs对22种单一水生物种的急性毒性数据,基于均值效应浓度值(EC₅₀)构建物种敏感性分布(SSD)模型,并计算得到5%危害浓度(Hazardous Concentration for 5%of species,HC₅)和潜在影响比例(Potential Affected Fractions,PAF).研究结果发现：富勒烯(C₆₀)、石墨烯纳米片(GN)、氧化石墨烯(GO)、单壁碳纳米管(SWCNTs)、多壁碳纳米管(MWCNTs)的HC₅值分别为1.88、0.37、0.13、1.31、0.74 mg·L^-1,表明二维石墨烯家族材料比零维C₆₀和一维碳纳米管对水生生物表现出更高的生态风险.与5种金属基纳米颗粒物(MNPs)相比,CNMs对水生生物的生态风险低于MNPs.通过对不同暴露浓度下CN...     

《物权法》为什么没有规定渔业环境权?

渔业环境权是渔业权人在得到许可的渔业水域从事养殖、捕捞等生产活动时所拥有的保护渔业水域环境的权利。根据物权理论，渔业环境权是一种基于国家对渔业水域的所有权上派生的用益物权，是《物权法》中养殖权和捕捞权的构成要件，它同养殖或捕捞水生动（植）物的所有权、对得到许可的水域（水体）的占有或使用权一起，构成完整的养殖权或捕捞权。这就是现行法律制度没有规定独立的渔业环境权的原因。     

Hydrologic Connectivity and the Contribution of Stream Headwaters to Ecological Integrity at Regional Scales1

Abstract: Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water‐mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two‐thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large‐scale ecological effects of altering headwaters are amplified by land uses that alter runoff and nutrient loads to streams, and by widespread dam construction on larger rivers (which frequently leaves free‐flowing upstream portions of river systems essential to sustaining aquatic biodiversity). We discuss three examples of large‐scale consequences of cumulative headwater alteration. Downstream eutrophication and coastal hypoxia result, in part, from agricultural practices that alter headwaters and wetlands while increasing nutrient runoff. Extensive headwater alteration is also expected to lower secondary productivity of river systems by reducing stream‐system length and trophic subsidies to downstream river segments, affecting aquatic communities and terrestrial wildlife that utilize aquatic resources. Reduced viability of freshwater biota may occur with cumulative headwater alteration, including for species that occupy a range of stream sizes but for which headwater streams diversify the network of interconnected populations or enhance survival for particular life stages. Developing a more predictive understanding of ecological patterns that may emerge on regional scales as a result of headwater alterations will require studies focused on components and pathways that connect headwaters to river, coastal and terrestrial ecosystems. Linkages between headwaters and downstream ecosystems cannot be discounted when addressing large‐scale issues such as hypoxia in the Gulf of Mexico and global losses of biodiversity.     

Adequacy of Visually Classified Particle Count Statistics From Regional Stream Habitat Surveys1

Abstract: Streamlined sampling procedures must be used to achieve a sufficient sample size with limited resources in studies undertaken to evaluate habitat status and potential management‐related habitat degradation at a regional scale. At the same time, these sampling procedures must achieve sufficient precision to answer science and policy‐relevant questions with an acceptable and statistically quantifiable level of uncertainty. In this paper, we examine precision and sources of error in streambed substrate characterization using data from the Environmental Monitoring and Assessment Program (EMAP) of the U.S. Environmental Protection Agency, which uses a modified “pebble count” method in which particle sizes are visually estimated rather than measured. While the coarse (2?) size classes used in EMAP have little effect on the precision of estimated geometric mean (D_gm) or median (D₅₀) particle diameter, variable classification bias among observers can contribute as much as 0.3?, or about 15‐20%, to the root‐mean‐square error (RMSE) of D_gm or D₅₀ estimates. D_gm and D₅₀ estimates based on EMAP data are nearly equal when fine sediments (<2 mm) are excluded, but otherwise can differ by up to a factor of 2 or more, with D_gm < D₅₀ for gravel‐bed streams. The RMSE of reach‐scale particle size estimates based on visually classified particle count data from EMAP surveys, including variability associated with reoccupying unmarked sample reaches during revisits, is up to five to seven times higher than that reported for traditional measured pebble counts by multiple observers at a plot scale. Nonetheless, a variance partitioning analysis shows that the ratio of among site to revisit variance for several EMAP substrate metrics exceeds 8 for many potential regions of interest, suggesting that the data have adequate precision to be useful in regional assessments of channel morphology, habitat quality, or ecological condition.     

Legitimizing Fluvial Ecosystems as Users of Water: An Overview

We suggest that fluvial ecosystems are legitimate users of water and that there are basic ecological principles guiding the maintenance of long-term ecological vitality. This article articulates some fundamental relationships between physical and ecological processes, presents basic principles for maintaining the vitality of fluvial ecosystems, identifies several major scientific challenges and opportunities for effective implementation of the basic ecological principles, and acts as an introduction to three specific articles to follow on biodiversity, biogeochemistry, and riparian communities. All the objectives, by necessity, link climate, land, and fresh water. The basic principles proposed are: (1) the natural flow regime shapes the evolution of aquatic biota and ecological processes, (2) every river has a characteristic flow regime and an associated biotic community, and (3) aquatic ecosystems are topographically unique in occupying the lowest position in the landscape, thereby integrating catchment-scale processes. Scientific challenges for the immediate future relate to quantifying cumulative effects, linking multidisciplinary knowledge and models, and formulating effective monitoring and assessment procedures. Additionally, forecasting the ecological consequences of changing water regimes is a fundamental challenge for science, especially as environmental issues related to fresh waters escalate in the next two to three decades.     

Spatial and Temporal Performance of the MiniFACE (Free Air CO2 Enrichment) System on Bog Ecosystems in Northern and Central Europe

The Bog Ecosystem Research Initiative (BERI) projectwas initiated to investigate, at five climaticallydifferent sites across Europe, the effects of elevatedCO₂ and N deposition on the net exchange ofCO₂ and CH₄ between bogs and the atmosphere,and to study the effects of elevated CO₂ and Ndeposition on the plant biodiversity of bogcommunities. A major challenge to investigate theeffects of elevated CO₂ on vegetation andecosystems is to apply elevated CO₂concentrations to growing vegetation without changingthe physical conditions like climate and radiation.Most available CO₂ enrichment methods disturb thenatural conditions to some degree, for instance closedchambers or open top chambers. Free Air CO₂Enrichment (FACE) systems have proven to be suitableto expose plants to elevated CO₂ concentrationswith minimal disturbance of their natural environment.The size and spatial scale of the vegetation studiedwithin the BERI project allowed the use of a modifiedversion of a small FACE system called MiniFACE. Thispaper describes the BERI MiniFACE design as well asits temporal and spatial performance at the five BERIfield locations. The temporal performance of theMiniFACE system largely met the quality criteriadefined by the FACE Protocol. One minute averageCO₂ concentrations measured at the centre of thering stayed within 20% of the pre-set target for morethan 95% of the time. Increased wind speeds werefound to improve the MiniFACE system's temporalperformance. Spatial analyses showed no apparentCO₂ gradients across a ring during a 4 day periodand the mean differences between each sampling pointand the centre of the ring did not exceed 10%.Observations made during a windy day, causing aCO₂ concentration gradient, and observations madeduring a calm day indicated that short term gradientstend to average out over longer periods of time. On aday with unidirectional strong winds, CO₂concentrations at the upwind side of the ring centrewere higher than those made at the centre and at thedownwind side of the ring centre, but the bell-shapeddistribution was found basically the same for thecentre and the four surrounding measurement points,implying that the short term (1 sec) variability ofCO₂ concentrations across the MiniFACE ring isalmost the same at any point in the ring. Based on gasdispersion simulations and measured CO₂concentration profiles, the possible interferencebetween CO₂-enriched and control rings was foundto be negligible beyond a centre-to-centre ringdistance of 6 m.