bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of water transfer on aquatic insects in a stream in Hong Kong
Authors: Dudgeon David 
Published: February 2007

AbstractHong Kong streams serve as indirect catchments for storage reservoirs to which they are connected by a network of undergound tunnels. Water transfer to reservoirs reduces stream flow downstream of the extraction point, and surface flows may disappear in affected reaches during the dry season. The ecological effects of periodic dewatering on aquatic insects were investigated in Tai Po Kau Forest Stream, Hong Kong, where water extraction at a weir gives rise to intermittent flow immediately downstream of a well studied perennial stream section. Benthic samples were taken from the intermittent reach on 48 occasions over a two year period encompassing two dry seasons. Trends in total population densities were unclear, with considerable fluctuations over the study period. In contrast, species richness declined markedly after surface flow disappeared, reaching the lowest values at the end of both dry seasons. A rapid increase accompanied flow resumption on the onset of the summer monsoon, and maximum wet season values were up to five times greater than species richness during the dry season. Dry season declines in Ephemeroptera and Trichoptera were accompanied by a dramatic increase in Coleoptera (Elmidae and especially Helodidae). The situation was reversed during the wet season when Trichoptera (especially Cheumatopsyche and Chimarra) and Ephemeroptera (Leptophlebiidae, Baetidae and Heptageniidae) were numerous. Community structure in the intermittent reach recovered quickly from the dewatering disturbance, due largely to recolonization by drifting animals. At the scale investigated, the community was resilient to disturbance because a source of mobile colonists was available upstream. However, if dewatering affects reaches far downstream, the presence of suitable colonists in upstream reaches cannot be guaranteed, and recovery from disturbance will be delayed. Lowland streams in Hong Kong are often polluted and host to exotic species; in such circumstances the effects of water transfers are exacerbated and recolonization is hindered.
Mussels: The forgotten fauna of regulated rivers. A case study of the Caney Fork River
Authors: Layzer James B. , Gordon Mark E. , Anderson Robert M. 
Published: February 2007

AbstractDuring the past century freshwater mussel populations have declined precipitously throughout North America. Much of this loss has resulted from the construction of dams. In the Cumberland River system, 23% (22 species) of the historic mussel fauna is extinct or listed as endangered. Several additional species have either been extirpated from the Cumberland River or exist only in small, non‐reproducing populations. Mussels of headwater streams have been severely affected by coal mining and poor land use practices. An intensive survey was conducted in the Caney Fork River, a major tributary to the Cumberland River, to determine the historic and extant mussel fauna. The results indicate that at least 37 species of mussels have been extirpated from the Caney Fork River, mainly as a result of the construction and operation of the Center Hill Dam. Among the species extirpated, two are now extinct, five are endangered and five are candidates for listing as threatened or endangered. Effects associated with this dam include the inundation of 102 km of riverine habitat, the discharge of hypolimnetic water (which limits mussel reproduction) and an alternating pattern of stream bed scouring and dewatering. The recognition of mussel life history requirements during preconstruction could have reduced many of these effects.
Assessing the ecological effects of groundwater abstraction on chalk streams: Three examples from Eastern England
Authors: Bickerton Melanie , Petts Geoffrey , Armitage Patrick , Castella Emmanuel 
Published: February 2007

AbstractThe invertebrate communities and environmental characteristics of three English chalk streams; the rivers Wissey, Rhee and Pang, were investigated to determine the effects of groundwater abstraction. The data were collected as part of a larger study of 21 UK rivers subject to a variety of types of abstraction. A variety of analytical techniques, including a novel multivariate analysis (co‐structure analysis), and the use of species profiles, showed significant physical and biotic differences between the three rivers and between impacted and natural sites on each river. The observed faunal differences are discussed in relation to existing data on the impact of natural droughts on chalk streams, and the problems associated with determining the effects of non‐point source abstractions (such as from groundwater) are considered.
Stocking strategy for the rehabilitation of a regulated brown trout (Salmo Trutta L.) river
Authors: Aass Per 
Published: February 2007

AbstractRegulation of the catchment area of the Norwegian river Gudbrandsdalslågen began in 1919. The lowermost power station on the main river was completed in 1964 and is situated about 10 km above the large Norwegian lake, Mjøsa. The lake is the foraging area of the Hunder strain of brown trout, the fastest growing of all Norwegian trout. The running of the power plant has led to a severe reduction in water flows below the dam, and the most important spawning and nursery areas of the Hunder strain has been affected. The natural smolt production has been permanently reduced. The rehabilitation programme has included the construction of a fish ladder through the dam and a fixed minimum flow. A hatchery was built and a stocking programme using the local strain was implemented. The effect of stocking has been the easiest of the relief measures to evaluate. Hatchery reared fish constitute a growing share of the spawning population. During the last three years their share has been close to 60%. Reared fish constitute 30–40% of the trout caught in Lake Mjøsa. The average and best returns of tagged groups have been 25 and 50%, respectively, but return rates are highly dependent on release length and time and place of stocking.
Channel changes associated with two adjacent weirs on a regulated lowland alluvial river
Authors: Thoms M. C. , Walker K. F. 
Published: February 2007

AbstractSurvey data from 1906 and 1988 for the lower River Murray, Australia, reveal changes in channel morphology associated with the construction of Locks 2 and 3 (1925–8), which form contiguous pools in the Valley and Gorge sections, respectively. Regulated annual flows are less than half the volume of natural flows, and the frequency of maximum flows has decreased. Upstream weirs have reduced the sediment supply to the study reach by 1.05 × 106 tonnes per annum. The trap efficiencies of Pools 2 and 3 from 1906 to 1988 were 8 and 13% respectively, with retention channel of 80723 and 267470 tonnes. Responses over the past 60–70 years have differed between the pools‐some channel characteristics have attained a new dynamic equilibrium and others have not. In Pool 3 the average bed slope has been reduced by 000004 (44%) and has attained equilibrium, but in Pool 2 the supply and redistribution of sediment have not been sufficient to reduce the bed slope. There are continuous areas of degradation and aggradation in Pool 3 but discontinuous areas in Pool 2, reflecting different stages in slope adjustment. Cross‐sections have become wider and shallower in Pool 3 but narrower and deeper in Pool 2. These adjustments are influenced by local boundary conditions, floodplain morphology and the position of the study reach in the sequence of weirs. In general, the situation in the lower Murray does not conform to conventional models of the impact of regulation, which are based on data from upland dams. The Murray's gross morphology remains as a relict of the natural, semi‐arid regime. Low contemporary stream energies and cohesive bank materials restrict the initiation of channel metamorphosis and prolong the time required for the completion of channel adjustment.
Effects of atmospheric exposure on chlorophyll a, biomass and productivity of the epilithon of a tailwater river
Authors: Angradi Ted R. , Kubly Dennis M. 
Published: February 2007

AbstractField experiments were conducted to determine the effects of atmospheric exposure on the chlorophyll a content, biomass and gross primary productivity (GPP) of littoral epilithon in the Colorado River below Glen Canyon Dam, Arizona. The chlorophyll a content of the epilithon was much more sensitive to exposure than the biomass. The epilithon was rapidly bleached during summer daytime exposures, but algal filaments remained attached for several weeks after reinundation. The percentage of initial chlorophyll a remaining after one day of exposure was not different from the percentage remaining after two days of exposure. However, significant reductions in chlorophyll a content were detected for daytime exposures as short as six hours. Overall, there were close inverse relationships (r2 ≥ 0–73) between the time exposed or cumulative solar radiation (400–700 nm) and the percentage of initial chlorophyll a remaining after reinundation. The GPP of Cladophora glomerata‐dommaled epilithon from the permanently inundated channel was 10 times higher than the GPP of epilithon from the zone of daily water level fluctuation. Experimental atmospheric exposure of the epilithon from each zone reduced the GPP, but not the assimilation ratio (GPP per unit of chlorophyll a) of the epilithon.The Glen Canyon epilithon has low resistance to exposure disturbances, and recolonization is slow under hydropower peaking flow regimes. Cladophora glomerata has an important structural role in Glen Canyon, the disruption of which is likely to precipitate effects at higher trophic levels.
Nature, mass and preferential sites of coarse woody debris deposits in the lower ain valley (Mollon reach), France
Authors: Piegay Herve 
Published: February 2007

AbstractCoarse woody debris (CWD) has been examined in a section of the Ain, a sixth order piedmont river with an actively meandering channel and a wooded floodplain. The spatial distribution of CWD, its mass and forms of accumulation are controlled by the hydrodynamics and the retention capacity of the forest. A typology shows the relative importance of woody debris in the mosaic of patches and the essential role of the ecotonal zones. The mass of debris varies from 0001 t ha−1, to more than 200t ha−1, but is lower than those observed in certain American rivers. Most of the material is deposited in the margins and forms a narrow debris line.The restocking in woody debris is recent in Europe and tends to diversify the environment. This affects the researcher and the planner. The first considers this transit of material as a useful hydromorphodynamic and biodynamic tool which is easy to evaluate, and the second considers it as a restoring and generative vector, the ecological functions of which are recognized. Its effect is stronger today as the watershed area tends to be subjected to a decrease in agricultural activity.
Near‐substrate hydraulic conditions under artificial floods from peaking hydropower operation: A preliminary analysis of disturbance intensity and duration
Authors: Gore James A. , Niemela Scott , Resh Vincent H. , Statzner Bernhard 
Published: February 2007

AbstractFST hemispheres of identical size but varying density were used to evaluate the intensity and duration of near‐bottom shear stresses during peaking hydropower floods of various magnitudes (maximum 345 m3 s−1; baseflow 2.75 m3 s−1). The FST values at single points were recorded at rapid intervals along previously surveyed transects during the rising limb of flood events at various distances from the hydropower facility. Whole transect evaluations were ‐accomplished after the ‘flood’ level had stabilized.Measurements of over 1300 FST values were significantly correlated with mean water column velocity and complex hydraulic conditions such as turbulence, shear velocity and viscous sublayer. FST hemispheres are a rapid means of characterizing hydraulic conditions in medium order rivers. Changes in near‐substrate hydraulic conditions were patchy and could be classified in terms of risk to fauna of either dislodgement or physical damage. Low risk (class 1) changes occurred when FST values increased rapidly but returned to initial values after a short period of time (< 90 minutes) from the arrival of the peaking wave. Medium risk (class 2) changes occurred when FST values increased rapidly and decreased after a short period of time, but remained at levels higher than before the arrival of the flood wave. High risk (class 3) changes occurred when FST values increased rapidly and remained at high levels during the entire flood event.It is suggested that floods that do not initiate significant bed movement create a mosaic of patches of variable disturbance risk to benthic fauna. Rapid evaluation by FST hemispheres could be used to characterize the overall disturbance potential for the channel by the construction of a weighted index based on the frequency of the various risk classes occurring in the reach being evaluated. A more appropriate analysis of impacts of peaking hydropower and other flood events must include the existence of hydraulic refugia and the movement patterns of both benthic species and those species that occupy the water column.
The fish ladder at the itaipu binational hydroelectric complex on the paraná river, Brazil
Authors: Borghetti J. R. , Nogueira V. S. G. , Borghetti N. R. B. , Canzi C. 
Published: February 2007

AbstractA study was carried out from 23 October to 19 November 1992 to determine the ability of fish to ascend the fish ladder at the ITAIPU dam, to identify the species attracted and to evaluate possible fish selection. The results show that some species of fish can ascend the ladder during the migratory period; the dam is non‐selective with respect to species, but selective with respect to fish size as a result of the presence of reduced openings. The ladder was ascended by both scaly species from surface waters (agile movers) and by deep water species which were characterized by slow movements. An average of 2892 fish ascended the ladder each day. The weight and length of fish recorded ranged from 336.0 to 3676.0 g and from 30.2 to 71.3 cm, respectively. The largest group of migrating fish was the curimba (Prochilodus scrofa). The high ratio of 72% of fish in the gonadal development stage, classified as ‘maturing’, indicates that the species caught in the ladder were migrating for reproduction purposes.
Downstream effects of a new hydropower impoundment on macrophyte, macroinvertebrate and fish communities
Authors: De Jalon Diego Garcia , Sanchez Pablo , Camargo Julio A. 
Published: February 2007

AbstractThe downstream effects of Valparaíso Reservoir (Río Tera, north‐western Spain) on macrophyte, macroinvertebrate and fish communities are examined by comparing their respective structures before (1986) and after (1990‐1991) the creation of this hydropower impoundment. A single sampling station was selected 2.4 km below the dam. Macrophytes significantly (p < 0.05) decreased their total biomass, although the species composition remained dominated by two species (Myriophyllum verticillatum and Ranunculus fluitans). The macroinvertebrate community, on the other hand, exhibited a significant (p < 0.05) decrease in taxonomic richness, total density and total biomass. In general, planarians, ephemer‐opterans, coleopterans, plecopterans and trichopterans disappeared or decreased their abundances. Scrapers (as relative biomass) were the functional feeding group most adversely affected by the new flow regulation. With regard to the fish community, the most significant change was the absence of all resident coarse fishes (cyprinids, primarily) at the sampling site during the 1990 and 1991 sampling surveys. Conversely, salmonids (Salmo trutta) persisted; the trout population was dominated by individuals of the 0+ age group (⩽ 1 year old) both before and after the construction of Valparaíso Dam. It is concluded that short‐term flow fluctuations induced by hydroelectric power generation were the main factor causing the observed adverse effects. In this respect, some management measures to minimize these effects are recommended.
Origin and abundance of lake whitefish (Coregonus clupeaformis) congregating below a hydroelectric control dam in northern Canada
Authors: Barnes N. E. , Bodaly R. A. 
Published: February 2007

AbstractThe abundance and origin of lake whitefish (Coregonus clupeaformis) congregating downstream of the Missi Falls control dam at the outlet of Southern Indian Lake (SIL) in northern Manitoba, Canada were studied during two successive open water seasons. In 1986 the number of lake whitefish below the dam increased to almost 90000 in the autumn and most of these fish were physiologically ready to spawn. Morphological comparisons indicated that most of these fish originated from SIL and were apparently attempting to return to it. Flows through the dam in this year were high and similar to those before the diversion of the Churchill River. In 1987 there were fewer fish of SIL origin below the control dam and the numbers decreased over the summer. Discharge through the dam was much lower in 1987 than before diversion. The number of lake whitefish below the dam that appeared to originate from lakes downstream of Missi Falls on the lower Churchill River varied from 2000 to 12000 over the whole study period. These fish may have been attracted to the control dam by local environmental conditions such as cool water temperatures. The effects of the control dam on lake whitefish movements and distribution was not predicted despite extensive pre‐project studies. These effects should receive more attention in the prediction of impacts of boreal hydroelectric projects.
Improving surface‐analysis methods for characterization of advanced materials by development of standards, reference data, and interlaboratory comparisons
Authors: Baer D. R. 
Published: February 2007

AbstractThis paper summarizes the results of two surveys examining current needs for improved analyses of surfaces. Surfaces and interfaces are increasingly important to science and technologies associated with nanoparticles, nano‐structured materials and other complex materials including those associated with information systems and medical or biological applications. Adequate characterization of advanced materials frequently requires application of more than one analysis method along with the need to analyze data in increasingly sophisticated and sometimes interrelated ways. It is useful for both new and experienced analysts to have ready access to best practices for obtaining accurate and useful information from a variety of different analysis tools. The International Organization for Standardization (ISO) Committee TC 201 on surface chemical analysis and the ASTM Committee E‐42 on surface analysis are working to address these needs by assembling guides and standards reflecting the collective experience and wisdom of experts in this community. Published in 2007 by John Wiley & Sons, Ltd
A database approach for information communication in a peer‐to‐peer collaborative CAD environment
Authors: Ma Haoxue , Risch Tore 
Published: February 2007

AbstractTimely and efficient information communication is a key factor in ensuring successful collaboration in engineering collaborative design. This work proposes a database approach to support information communication between distributed and autonomous CAD systems. It provides the designer with an easy and flexible way, a project‐based propagation meta‐table, to specify what parts of a CAD information model should be communicated to other collaborating designers. A CAD peer manager, containing a peer database that stores information to be exchanged with the other collaborators, wraps each participating CAD system. The peer manager identifies changes made to the CAD model by using stored procedures and active rules in the peer database that are automatically generated based on the propagation meta‐table. The identified updates are propagated in a timely manner to other peers via inter‐database message passing, thereby minimizing the volume of necessary information to be exchanged. Furthermore, remote peer designers can flexibly incorporate, filter, or delete received updates by using a propagation control interface, which is also used to issue user's commands to download the data from the CAD system to the peer database and lookup the received messages in the peer database. The approach is applicable on any CAD system having a CORBA interface and can also be applied to other kinds of object‐oriented interfaces. Copyright © 2007 John Wiley & Sons, Ltd.
Influence of Cu2+‐organic montmorillonites on thermal decomposition and smoke emission of poly(vinyl chloride) by cone calorimetric study
Authors: Yang Zhihua , Li Bin , Tang Fei 
Published: February 2007

AbstractCu2+‐Organic montmorillonites were prepared by modifying Na+ montmorillonite (Na+‐MMT) with silane coupling agents and cupric sulfate. PVC/organic montmorillonite composites were prepared by the melt intercalation method. Morphological structure of modified MMT and PVC/MMT was obtained by using XRD and SEM. The XRD results showed that silanes and Cu2+ were intercalated among interlayers and that modified MMT may have exfoliated dispersion in PVC. Effects of Cu2+‐organic montmorillonites on decomposition and smoke emission of poly(vinyl chloride) (PVC) in the flaming mode were investigated by using a cone calorimeter at an incident heat flux of 25 kW·m−2. Cone experimental data demonstrated that the Cu2+‐organic montmorillonites prepared were new effective smoke suppressants. They clearly promoted an early HCl elimination, crosslinking reactions, and char residue formation, based upon the decomposition parameters of mass loss, mass loss rate, and time of initial decomposition (tinitial). Cu2+‐Organic montmorillonites decreased peak heat release rate, total heat release, peak smoke production rate, total smoke production, and smoke extinction area during the flaming process. The smoke‐reducing efficiency of Cu2+‐organic montmorillonites (Cu2+‐OMMTs) was the best. However, the content of cupric ion was only 0.6–0.8% in Cu2+‐OMMTs and 0.03–0.04% in PVC composites. They may make the smoke‐reducing efficiency reach 45–50%. This result further demonstrates that Cu2+ ion is a very effective smoke suppressant for PVC. J. VINYL ADDIT. TECHNOL., 13:31–39, 2007. © 2007 Society of Plastics Engineers.
Hydrothermal Synthesis, Structure and Property of a Zinc Coordination Polymer Based on Aromatic Polycarboxylate and Phenanthroline Ligands
Authors: Yu Xiao‐Yang , Lu Jing , Yu Jie‐Hui , Zhang Xiao , Xu Ji‐Qing 
Published: February 2007

AbstractA zinc coordination polymer [Zn(μ2‐H2bta)1/2(μ4H2bta)1/2(phen)(H2O)]n (1) (H4bta = benzene‐1,2,4,5‐tetracarboxylic acid, phen = 1, 10‐phenanthroline) has been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric and single‐crystal X‐ray diffraction analyses. Compound 1 displays pucker layer structure formed from Zn2+ ions and μ2‐H2bta2− and μ4‐H2bta2− bridging ligands, and it is linked into three dimensional (3D) supramolecular frameworks through the hydrogen bonds and π‐π interactions. It exhibits strong blue fluorescence at room temperature in the solid state.