bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fragmentation study on butanolides with tandem mass spectrometry and its application for the screening of ScbR‐captured quorum sensing molecules in Streptomyces coelicolor A3(2)
Authors: Joo Hwang‐Soo , Yang Yung‐Hun , Lee Chang‐Soo , Kim June‐Hyung , Kim Byung‐Gee 
Published: February 2007

AbstractStreptomyces coelicolor has a quorum sensing (QS) system triggered by small diffusible signaling molecules, i.e. butanolides (or γ‐butyrolactones) and their cognate DNA‐binding receptors. Using the DNA‐binding receptors as an affinity capture matrix, the butanolides can be easily enriched and identified. For the identification and screening of the butanolides, the diagnostic peak lists generated by the tandem mass spectrometric (MS/MS) fragmentation analysis of chemically synthetic butanolides were used. In the case of using ScbR as the capture matrix, SCB1, a previously well‐known butanolide, and Acl‐1 (or SCB3)‐type butanolides having one more carbon in the acyl chain than SCB1, were detected. This is the first report directly demonstrating that Acl‐1 is able to bind to ScbR in S. coelicolor. Our proposed method using both diagnostic peak lists of butanolide and the purified receptor protein as an affinity capture tool can be applied to rapidly screen QS molecules in vitro. Copyright © 2007 John Wiley & Sons, Ltd.
Ecological effects of groundwater pumping and a natural drought on the upper reaches of a chalk stream
Authors: Wright J. F. , Berrie A. D. 
Published: February 2007

AbstractThe ecological effects are examined of a three‐month test of a groundwater pumping scheme, which augmented flow in a chalk stream in autumn 1975. The impact on the macrophytes and invertebrates in the upper perennial stream which received pumped water were found to be minimal.After pumping ceased, a dry winter and spring led on to a major drought in summer 1976. This prompted operational use of the groundwater pumping scheme in late summer 1976 prior to heavy winter rains which resulted in a return to the normal pattern of discharge in 1977. The ecological effects of the drought, the operational pumping and its aftermath are assessed on three channel reaches: the intermittent zone of the stream, which remained dry throughout 1976; the upper perennial channel where changes in flow regime were most severe; and the lower perennial section of the stream.Drying of the intermittent section for over one year had more severe effects on the invertebrates and fish populations than on the macrophytes, which recovered rapidly after the return of flow. In the upper perennial section, the drought led to siltation of the river‐bed, loss of macrophytes and limited habitat diversity for the invertebrate fauna. Further downstream, effects were still detectable, though less severe.Operational pumping brought immediate benefit to the perennial stream by increasing the river width, removing silt and encouraging growth of macrophytes, which provided habitat and food resources for invertebrates. However, in the upper perennial reach, where siltation and loss of macrophytes had been severe, regrowth of macrophytes was slow and the effects of the drought on both macrophytes and invertebrates were still apparent in autumn 1977. It is proposed that a pumping policy that maintains river flow above the level at which siltation and subsequent loss of macrophytes occurs could minimize undesirable ecological effects of extreme low flows.
Channel degradation in the middle Arve river, France
Authors: Peiry J.‐L. 
Published: February 2007

AbstractMan‐induced channel changes within Alpine alluvial rivers are investigated. For the middle Arve river, a series of long profiles surveyed between 1856 and 1981 show deep and rapid degradation since the beginning of the 1950s. This tendency is related to gravel extraction, weir construction, and embankment, and is shown to characterize Alpine rivers.
Accumulation of fine sediment within substrate gravels along two regulated rivers, UK
Authors: Petts Geoffrey E. 
Published: February 2007

AbstractThe channel‐bed materials have a marked influence on the biota of lotic systems. Experimental studies suggest that flow regulation, specificially the reduction in magnitude of flood events, may lead to the infiltration of fine particles into, and the concentration of these sediments within, open framework gravels downstream from tributary sediment sources. This paper examines the distribution of fines (sub‐2 mm), within channel substrate gravels along two regulated rivers in upland Britain.Bulk‐ and freeze‐sample techniques were used: the latter yielded volumes of fines five times those of the former. This emphasizes the problem of wash‐out during bulk‐sample collection, especially in compact, coarse gravel substrates. Nevertheless, the same spatial pattern was revealed by both data sets. Along both regulated rivers, the proportion of the substrate finer than 2 mm exceeds 20 per cent, by weight, below tributary confluences, contrasting with values for non‐regulated sites of less than 5 per cent. Both the amount and size of matrix sediments decrease downstream from the confluences. The spatial scale of the impact is small and the resultant ecological consequences of substrate sedimentation are likely to be localized.
Short communications monitoring the impact of dams on the downstream physical environment in the tropics
Authors: Olofin E. A. 
Published: February 2007

AbstractIn the main, the assessment of environmental impact of dams is not undertaken in feasibility surveys of dam‐related projects in the Tropics, as it should. Consquently, post‐implementation investigations (mostly by research students) continue to reveal undersirable effects. The lack of appropriate data on which to base predictions in proposed projects, or to assess environmental impacts in ongoing ones, is a major problem. It is argued that continuous monitoring of existing projects can help to fill this data gap. Such monitoring should cover the entire basin affected, taking into account environmental variables of the upstream, reservoir, and downstream systems. This paper considers the downstream system. Variables of importance include: soil erosion and sediment yield; channel morphometry; discharge and runoff pattern and volume; and changes in vegetation cover, water chemistry and water quality. Field measurements and observations, laboratory analyses, and statistical inferences are required to yield acceptable results. Such results are expected to enhance a better understanding (through impact assessment) and management of existing projects, on the one hand, and to aid wise predictions (at the feasibility stage) of environmental effects of new projects, on the other.
Historical changes of a large river in an urban area: The Garonne river, Toulouse, France
Authors: Fortuné M. 
Published: February 2007

AbstractMan‐made structures have greatly modified the flow pattern of the Garonne River at Toulouse (France) since at least the 12th century. The first of many small dams was constructed in 1182. Destructive floods regularly destroyed the dams, flooded protions of the city, changed the river course, and destroyed the wooden bridges, the first of which was probably built during the first half of the 13th century. The first stone bridge was completed in 1660, after a 100 year period of constuction.After 1680 attempts to control the river led to a variety of river responses: increased sedimentation in some locations and erosion in others, a reduction in the number of islands from seventeen to four, and a 63 per cent reduction in the length of shoreline in the urban area of Toulouse.
Water quality management: A regional perspective— The severn‐trent area
Authors: Brewin D. J. , Martin J. R. 
Published: February 2007

AbstractThe management of water quality in U.K. rivers is going through a period of major change due to the proposed reorganization of the water industry and to the increasing demands on river resources and the imposition of stricter environmental standards. Changes to the river classification scheme and effluent consent conditions are discussed. A brief summary is given of some of the quality problems that are of particular concern in the Severn‐Trent area. The impact on quality of river regulation including in‐river purification lakes is described. Catchment models have been developed to assist with the management of river resources. These and other river quality modelling techniques are reviewed.
Regulation of the River Dee
Authors: Lambert Allan 
Published: February 2007

AbstractThis paper discusses the interdisciplinary approach statutorily adopted for the management of the intensively regulated River Dee. The role of the Dee Consultative Committee is discussed and the procedures and methods for river regulation are described. Particular problems arise during severe droughts and a Conservation Rule Curve, using the aggregated storage of the two main reservoirs, has been devised to act as the trigger for optional initiation of water conservation measures. The social and environmental benefits of the integrated management scheme are demonstrated. Areas of conflict have been, and must continue to be, resolved by consultation, cooperation, and compromise.
Regulating the River Severn
Authors: Douglas J. R. 
Published: February 2007

AbstractThe River Severn is the longest of Britain's regulated rivers: this chapter describes the geography of the river's catchment area, from its source in central Wales to the Bristol Channel where it flows into the sea. It then considers the historical development of the Severn as a water resource, culminating in the construction of Llyn Clywedog and more recently the Shropshire Groundwater Scheme to augment low river flows and support greatly increased abstractions. Plans for even more substantial development of the resource system appropriate to the rapid demand growth of the 1960s and early 1970s are discussed. Practical experience in regulating flows in the river gained during the drought of 1976 is described and used to explain recent developments in the practice and monitoring of river regulation.
Hydrological changes and river regulation in the UK
Authors: Higgs Gary , Petts Geoff 
Published: February 2007

AbstractWater levels of streams and rivers in the United Kingdom have been regulated by weirs for more than one thousand years, but regulation of the flow regime by impoundments began in the latter half on the 19th Century. Organized river flow measurements were not undertaken until 1935, and today the average record length is about 20 years. Only three gauging stations have provided data suitable for pre‐ and post‐impoundment comparisons. Other studies have relied on the comparison of regulated and naturalized discharges. In either case climate and land‐use changes make evaluation of the hydrological effect of impoundments problematic. This paper reviews research on hydrological changes due to river regulation in the UK, and presents a case study of the River Severn to evaluate the influence of Clywedog Reservoir on flood magnitude and frequency.Consequent upon dam completion, on average, median flows have been reduced by about 50per cent; mean annual floods have been reduced by about 30per cent; and low flows have been maintained at about 22 per cent higher than the natural Q95 discharge. However, marked differences exist between rivers. The direct effect of reservoir compensation flows and the indirect effect of inter basin transfers for supply have significantly increased minimum flows in most rivers, although in the case of the latter this involves the discharge of treated effluents. In contrast, the effects of impoundments on flood magnitude and frequency is less clear and on the River Severn, at least, changes in flood hydrology during the past two decades are shown to be more related to climate change than to river regulation.
Assessment of the water surface profile model: Accuracy of predicted instream fish habitat conditions in low‐gradient, warmwater streams
Authors: Osborne Lewis L. , Wiley Michael J. , Larimore R. Weldon 
Published: February 2007

AbstractThe Instream Flow Group's (U.S. Fish and Wildlife Service) Physical Habitat Simulation (PHABSIM) model, the major component of the incremental methodology (IFIM) is presently the most widely employed instream flow assessment procedure. PHABSIM consists of both biological and hydrological components. The Water Surface Profile (WSP) hydrologic model is commonly recommended and employed in many PHABSIM applications. While several recent studies have critically addressed and questioned the validity of PHABSIM as a management tool from a biological perspective, there has been surprisingly limited attention given to problems of use, accuracy, bias, and the effect of errors in the WSP hydraulic simulation on the final PHABSIM output (i.e. weighted usable area (WUA) estimates). Therefore, the purpose of this study was to examine the effectiveness of the WSP hydraulic model for predicting hydraulic conditions in low‐gradient, warmwater streams in east‐central Illinois. Attempts were made to calibrate the WSP model at four locations on the Salt Fork and Middle Fork rivers and compare simulated results to actual measured conditions at different discharges. We conclude that in low‐gradient warmwater streams, the WSP model: (1) does not adequately simulate low‐flow habitat conditions, due to an inability to calibrate the model; (2) is, at best, difficult to calibrate, even within hydraulically uniform channels; (3) requires several field measurements and calibrations to simulate a sufficiently wide range of naturally occurring flows: (4) provides poor estimates of cell depth and velocity; and, results in highly erratic and often poor estimates of WUA for adults and fry of smallmouth bass. Finally, our results indicate that similar or better estimates of actual WUA can be attained by monitoring the distributions of depth, velocity, and substrate at a series of representative transects at different discharges and interpolating WUA from observed field data using less expensive and time consuming regression models.
Mitigation, compensation, and future protection for fish populations affected by hydropower development in the upper Columbia system, Montana, U.S.A.
Authors: Fraley John , Marotz Brian , Decker‐Hess Janet , Beattie Will , Zubik Ray 
Published: February 2007

AbstractPursuant to the Northwest Power Planning Council's Fish and Wildlife Program for the Columbia River system, we estimated losses in fish populations and developed mitigation, compensation, and protection alternatives for reservoirs and downstream river reaches affected by hydropower development in the Flathead and Kootenai River systems in northwest Montana, U.S.A. The construction of Hungry Horse Dam has resulted in estimated annual losses of 65500 migratory juvenile westslope cutthroat and 1965 adult migratory bull trout from the Flathead Lake and River system. In addition, operations of Hungry Horse and Kerr dams caused annual losses conservatively estimated at 96300 river‐spawning and 131000 lakeshore‐spawning kokanee adults. Water level fluctuations caused by dam operations at Libby and Hungry Horse reservoirs result in: (1) altered thermal stratification, (2) indirect losses in phytoplankton and zooplankton production, (3) direct washout of phytoplankton and zooplankton through dam penstocks, (4) reductions in standing crop of benthic organisms and of insects on the water surface, and (5) reduced fish growth in the late summer and fall. Mitigative measures include: (1) 99.2 and 113.3 m3 s−1 minimum flows in the Flathead and Kootenai rivers respectively, to protect salmonid eggs and juveniles, (2) improvement of fish passage to restore migrations between the Flathead and Swan systems, and (3) biological rule curves for operations at Libby and Hungry Horse reservoirs. To compensate for fisheries losses, we recommend enhancement of spawning and rearing habitat, introductions of hatchery juveniles, and spawning channels. We recommend protection from further hydropower development for 100 stream reaches (1386 km) for fish species of special concern, and for outstanding sport fisheries. These and other measures will be considered by various agencies in developing an overall fisheries restoration plan which should be flexible, and employ principles of adaptive management. Effectiveness of the plan may be limited by heavy reliance on hatchery fish. Although mitigation efforts may not restore fish populations to pre‐dam levels, substantial benefits should be realized.
Responses of the sediment system of a regulated river to a scour valve release: Llyn Clywedog, mid‐Wales, U.K.
Authors: Leeks G. J. L. , Newson M. D. 
Published: February 2007

AbstractIn March 1985 engineering tests of scour valves at the base of the Llyn Clywedog regulating reservoir resulted in a controlled peak release discharge of 53m3 s−1 into regulated reaches of the upper Severn. To exploit this unusual opportunity, simple monitoring systems were set up within the first 50 km downstream to assess the morphological effects on bed and banks and the movement of bed and suspended sediments. The interpretation of suspended sediment transport patterns became the major analytical task following the release, since bedload and morphological impacts were minimal. In comparison with natural floods, the scour valve release exhibited suspended sediment concentrations usually associated with a five‐year event, but with a complex time and space pattern resulting from the release strategy. Wet antecedent conditions and the short duration of the scour valve release help to explain why impacts on the downstream channel were, otherwise, much more restricted than those of a water resource test release in 1975. Since scour releases can be planned with greater flexibility than major water resource releases, indications are that they should be made ‘on the back of’ natural high flows, although sensitive sites may require protection.
Proposals for inhibiting abundant phytoplankton growth at the head of a river reservoir
Authors: Kagawa H. 
Published: February 2007

AbstractIn a river reservoir, the Ishitegawa Dam Reservoir in Japan, sites of abundant phytoplankton growth were investigated in connection with the water movement in the reservoir from January 1982 to January 1984 by comparing the distributions of chlorophyll a, water temperature, and coliform bacteria (Project A). The results distinguished three types of phytoplankton growth, of which one type, the abundant surface growth at the head of the reservoir, was most frequently observed. This case was considered to be caused by mixing of the surface lake water with the inflowing nutrient‐rich river water at the shallow lake‐head. Subsequently the effects of dissolved calcium and magnesium on the chlorophyll a and phytoplanktonic particulate phosphorus concentrations at the head of the reservoir were investigated until December 1987 (Project B). A trophic index, named the Ca‐Mg index, was found which correlated positively with the chlorophyll a and phytoplanktonic particulate phosphorus concentrations in a logarithmic scale and varied in relation to the changes in the same index of the inflowing river water. Based on the ecological results of these two projects, two proposals are presented for inhibiting abundant phytoplankton growth at the head of a river reservoir. Proposal A: make the head deep and, in addition, create a strong near‐bottom underflow of the inflowing river water. Proposal B: make a bypass in order to cut off the inflow of river water in the case of a high Ca‐Mg index.
Measuring discontinuities in the ter river
Authors: Sabater F. , Armengol J. , Sabater S. 
Published: February 2007

AbstractIn this paper a method for measuring discontinuities in the spatial organization of a river produced by disturbances is presented. First of all, a way of doing comparable environmental gradients defined by different variables is proposed. To do so, all the variables have been transformed by means of the equation: Pi' = Pi ‐ Pmin/Pmax ‐ Pmin, as a previous measure of the parametric distances (Pij') between sites. When these parametric distances are plotted in relation to the geographical ones, the distortion between both river images appears as an expression of the changes occurring in each stretch, and the derivative dPij'/dx is a measure of its rate of change. To define a river gradient, we need to calculate the general trend of a variable, using direct gradient analysis. The fit of the results obtained from an undisturbed stretch to an empirical curve for all the river gives us a measure of the expected values for that river. The difference between expected and observed values can be a measure of the discontinuity. The same procedure has been used for an overall environmental and biological data. To this end, the Euclidean distance (ED) and a distance obtained from Factor score of a Principal Components analysis (PCA) have been calculated. Only the second method seems to be of general interest for studying discontinuities. Finally, the results of the first score loadings obtained from PCA of three groups of variables (physical and chemical, physiographical and morphological, and phytobenthic) have been used to do a comparison between the parametric images of the River Ter.
A study of physical parameters at the spawning sites of the european grayling (Thymallus thymallus L.)
Authors: Gönczi Adam P. 
Published: February 2007

AbstractAn investigation of the spawning sites of European grayling, Thymallus thymallus (L.), in two Swedish rivers revealed narrow range in their physical parameters.The bottom substrate was composed of 10–20 per cent sand, 50–70 per cent gravel (<2cm), 20–30 per cent stones (2–10cm), and a few bigger stones (>10cm in diameter). Eggs were found only where the gravel thickness was more than 5 cm. The depth varied between 30–50cm. Mean depth for 22 different spawning sites was 36cm. The water velocity varied between 23–90cm s−1, average 54 cm s−1. The temperature at the start of spawning was 3.9°C and at the end it was about 9°C.The results indicate the narrow range in physical parameters at the spawning sites. Small changes in the environment caused by regulation of river flow or water level may disturb the spawning behaviour of grayling and cause a decrease in population size or even extinction.
Flushing flow recommendations for maintenance of salmonid spawning gravels in a steep, regulated stream
Authors: Reiser Dudley W. , Ramey Michael P. , Beck Stuart , Lambert Thomas R. , Geary R. Eugene 
Published: February 2007

AbstractA study was conducted to develop flushing flow recommendations for maintaining the quantity of salmonid spawning gravels in the North Fork of the Feather River, a regulated stream in California, U.S.A. This required the development of a technique which would prescribe flows to remove sediments from the gravels without removing the gravels themselves, which are in finite supply in the river.Field studies involved the use of a ‘two‐point‐are’ procedure which allowed depth, velocity, and substrate measurements to be concentrated over spawning gravels at each site. Measurements were repeated at each site at three different flows ranging from 1.7 to 11.3 m3 s−1. The local velocity and depth measurements were used to evaluate hydraulic conditions within areas containing spawning gravels. Four flow levels were derived which would provide varying degrees of sediment transport and flushing; (1) surficial flushing of gravels; (2) mobilization of gravels; (3) surficial flushing of cobbles; and (4) mobilization of cobbles.Results of the study indicated a flushing flow of 56.6 m3 s−1 occurring as a planned release or natural flow for from 1–3 days would be sufficient to transport sediment from spawning gravels. This flow was intermediate to levels which maximize surficial gravel flushing and levels which maximize surficial cobble flushing.