bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fish Passage in a Western Iowa Stream Modified by Grade Control Structures
Authors: Litvan Mary E. , Pierce Clay L. , Stewart Timothy W. , Larson Chris J. 
Published: October 2008

Abstract
Grade control structures (GCSs) are commonly used in streams of western Iowa to control bank erosion and channel headcutting but may be barriers to fish passage. From May 2002 to May 2006, we used mark–recapture methods to evaluate fish passage over a total of five GCSs, ranging in slope (run : rise) from 13:1 to 18:1 in Turkey Creek, Cass County, Iowa. Three structures, over which limited fish movement was documented from 2002 to 2004, were modified in the winter of 2004–2005 to facilitate fish passage. Before modification, the majority of recaptured fish were recaptured at the station where they were originally marked; only 1% displayed movement between sites and either upstream or downstream over a GCS. After modification fish passage improved, 14% of recaptured fish displayed movement either upstream or downstream over a GCS. Individuals of four target species—channel catfish Ictalurus punctatus, yellow bullhead Ameiurus natalis, black bullhead A. melas, and creek chub Semotilus atromaculatus—passed over at least one modified structure. The majority of documented movements over GCSs were in the upstream direction and occurred in late spring and early summer, when streamflow was relatively high. Although we documented low numbers of fish passing both upstream and downstream over GCSs, these structures are probably barriers to fish movement during periods of low flow and when there is a structural failure, such as in-channel movement of riprap. Grade control structures are pervasive in western Iowa streams; nearly every low-order stream contains at least one instream structure. To sustain fish populations, management efforts should focus on constructing or modifying GCSs to allow fish passage.
Predictive Value of a Lake Sturgeon Habitat Suitability Model
Authors: Haxton Tim J. , Findlay C. Scott , Threader R. W. 
Published: October 2008

Abstract
Although many fish habitat suitability models (HSMs) have been developed and used in wildlife management and conservation planning, comparatively few have been independently validated. Given the importance of such models in habitat management and conservation policy, the extent to which they accurately predict population parameters (e.g., abundance or recruitment) is a critical issue. Here we apply an HSM recently developed for lake sturgeon Acipenser fulvescens in northern rivers to three reaches of the Ottawa River, using measurements of the model's key variables (substrate type, water depth, and velocity) to generate spatially explicit predictions of habitat suitability. We then test the predictive power of the model by comparing lake sturgeon catch per unit effort (CUE) when using short-set gill nets in areas predicted to have good (habitat suitability index values &gt;0.6) and poor (values &lt; 0.3) adult and juvenile foraging habitats. Consistent with model predictions, significantly more lake sturgeon were caught at sites within river reaches predicted to be of high quality than at those predicted to be of low quality. Moreover, the average CUE at the reach scale correlated positively with the average predicted habitat foraging quality. On the other hand, the predictive power was generally low, such that most of the variation in CUE was unexplained by the fitted models. These results suggest that although the lake sturgeon HSM developed for northern rivers has some predictive power in other contexts, the uncertainty of its predictions is still rather high. We suggest that (1) considerably more effort be devoted to the independent validation of both existing HSMs and those still in development and (2) in the absence of independent validation and bona fide estimates of their predictive power, such models be used circumspectly in conservation management and planning.
Impact of hydromorphology and spatial scale on macroinvertebrate assemblage composition in streams
Authors: Verdonschot Piet FM 
Published: October 2008

Abstract
Stream risk assessment and restoration requires understanding of the controlling factors and the scale at which they act. The role of hydromorphology, along with physicochemistry, was for a long time neglected, and scale issues were barely tackled. In this study, both the role of hydromorphology and the relevance of scale are studied. For this purpose, the macroinvertebrate community of the stream is used as the scale of the target biota. Next, the following research question is dealt with: At which scale, and to what extent, do hydrology and morphology along with physicochemistry explain stream macroinvertebrate distribution? Three data sets were used: The European AQEM study, the Dutch streams study, and an extensive habitat-preference study. Ordination was used to relate the macroinvertebrate species composition to the (hydromorphological) environment for both the European study and the Dutch stream study data. To explore the strength of one or more variables in explaining the macroinvertebrate distribution over the sampling sites, the fraction of the sum of canonical eigenvalues was used as a measure. To determine the preference for a specific habitat type of each macroinvertebrate species in the habitat preference study, the index of representation was calculated. The European study showed that streams within a more limited geographic area tend to carry macroinvertebrates whose distribution is better explained by stream stretch and in-stream variables. However, even within stream type catchment and stream valley, variables almost equally add to the explanation of the macroinvertebrates distribution. The explanatory power of hydrological and physicochemical variables increased toward smaller scales, and morphological variables showed an equal explanatory power over the different scales. In the Dutch streams study, stream level was much better explained in comparison to the habitat level. Geographical, morphological, and physicochemical variables were strong explanatory variables. For both habitat and stream, the stream stretch variables contributed most to the explanation of macroinvertebrate distribution, whereas microhabitat variables were less explanatory. The habitat preference study supported the observation that habitat provided less explanation than stream stretch. Only 15% of the macroinvertebrate species showed a clear habitat preference; none showed an obligatory one. In conclusion, stream macroinvertebrates distribution is best explained by local stream-stretch variables, provided those variables are contained within a catchment and stream valley context. Differences in vulnerability and biotic capacity between macroinvertebrate species determine the assemblage present. Applying this knowledge in water management means that any risk assessment and restoration effort needs a hydromorphological context.
Toward an integrated assessment of the ecological and chemical status of european river basins
Authors: von der Ohe Peter C , De Deckere Eric , Prüß Andrea , Muñoz Isabel , Wolfram Georg , Villagrasa Marta , Ginebreda Antonio , Hein Michaela , Brack Werner 
Published: October 2008

Abstract
Here, recommendations to improve ecological and chemical status assessments in accordance with the European Water Framework Directive (WFD) are made on the basis of experience gained from the MODELKEY project database, linking existing biological and chemical monitoring data of 3 case study river basins (Elbe, Scheldt, and Llobregat). The data analysis within and across river basins revealed major obstacles to be tackled, including scarcity of matching ecological and chemical monitoring sites for cause–effect relationships as well as a general lack of stressor-specific metrics for single biological quality elements (BQE) to enable a comprehensive risk assessment of all predominant stressors, including toxicity. An example of such a metric, which is recommended for the BQE of benthic macroinvertebrates, is the trait-based species-at-risk index (SPEAR) that correlated well with a respective measure for toxic stress, referred to as toxic units, based on simple mixture toxicity concepts. Surprisingly, the assessment of chemical status of a total of 695 monitoring sites for 2000 to 2004 showed that environmental quality standards (EQSs) were exceeded for at least 1 of the currently 41 priority pollutants (PPs) in 92% to 98% of the cases in all 3 of the river basins, which, according to definition, indicates potential effects on ecological status. A comparison of compliance with EQSs for 41 PPs with a respective effect threshold (derived for benthic macroinvertebrates) revealed that the rather conservative concept of chemical status is most likely not protective in all cases. Furthermore, to account for the many other compounds that are detected frequently in European surface waters and that may also have ecotoxicological effects, we introduced a provisional predicted no-effect concentration that is in accordance with the EQS methodology and is suggested to identify potential emerging compounds for which no or insufficient toxicity data exist. In conclusion, this study aims to support the implementation of the WFD by drawing conclusions from the analysis of heterogeneous data sets of various member states and by introducing new tools to move toward an integrated European assessment of ecological and chemical status.
Uncertainty in environmental risk assessment: implications for risk-based management of river basins
Authors: Ragas Ad MJ , Huijbregts Mark AJ , Henning-de Jong Irmgard , Leuven Rob SEW 
Published: October 2008

Abstract
Environmental risk assessment is typically uncertain due to different perceptions of the risk problem and limited knowledge about the physical, chemical, and biological processes underlying the risk. The present paper provides a systematic overview of the implications of different types of uncertainty for risk management, with a focus on risk-based management of river basins. Three different types of uncertainty are distinguished: 1) problem definition uncertainty, 2) true uncertainty, and 3) variability. Methods to quantify and describe these types of uncertainty are discussed and illustrated in 4 case studies. The case studies demonstrate that explicit regulation of uncertainty can improve risk management (e.g., by identification of the most effective risk reduction measures, optimization of the use of resources, and improvement of the decision-making process). It is concluded that the involvement of nongovernmental actors as prescribed by the European Union Water Framework Directive (WFD) provides challenging opportunities to address problem definition uncertainty and those forms of true uncertainty that are difficult to quantify. However, the WFD guidelines for derivation and application of environmental quality standards could be improved by the introduction of a probabilistic approach to deal with true uncertainty and a better scientific basis for regulation of variability.
Dynamic weighting system for water quality index
Authors: Sargaonkar Aabha P. , Gupta Apurba , Devotta Sukumar 
Published: October 2008

Water quality standards are developed world over by National and International agencies for pollution control decision-making. Use-based water quality classification criteria and Water Quality Indices (WQIs) also play important role in assessment of water resources for their suitability with reference various uses. Formulation of value function curves and weights assigned to parameters in WQIs are often defined by local water experts and hence WQIs are known to inherit subjectivity. Assignment of weights a priori to various water quality parameters results in misclassification of water quality by WQI.
A method of dynamic weighting has been developed in the present work to assign weights to water quality parameters with due consideration to their pollution effect at a particular site. Application of a methodology to Overall Index of Pollution (OIP) provides water quality classification of Indian rivers as “Polluted”, “Acceptable”, and “Slightly Polluted”, which is comparable with the reported CPCB classification as well as with the statistical index CCME-WQI. The methodology developed is general and can be applied to any subjective index. This is exemplified by dynamically weighting the parameters in NSF-WQI for Red and Waikato rivers. Dynamic weighting system provides a true representation to comprehend water quality classification and to achieve River Quality Objectives.
The secret to achieving reliable biological phosphorus removal
Authors: Thomas M. P. 
Published: October 2008

The enhanced biological phosphorus removal (bio-P) activated sludge process has a reputation for variable performance. A significant factor contributing to variability in bio-P was found to be related to microbial population dynamics involving the competitive growth of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). It was found that the key factor in their competitive growth was the specific type of VFA in the influent to the bioreactor. The PAOs seem to have a competitive advantage to use propionate, whereas the GAOs have a competitive advantage to use acetate. Therefore, the secret to achieving reliable biological phosphorus removal was to ensure an adequate supply of propionate, or an alternative substrate such as molasses that can be readily fermented to propionate.
When Noosa WWTP was commissioned in Nov 1997, and for several years afterwards, the bio-P performance was found to be variable. This paper outlines the findings of the research and optimisation program that was carried out, which identified the cause of the variability in bio-P and subsequently lead to implementation of an improved operating strategy. The recent long-term results demonstrate that reliable bio-P can be achieved in full-scale wastewater treatment plants without dosing metal salts. The effluent total phosphorus has been maintained below 0.5 mg/L since Jul 2001 and the 50 percentile result for the last 12 months was 0.2 mg/L.
Diatom communities of lake/stream networks in the Tatra Mountains, Poland, and the Swiss Alps
Authors: Kawecka Barbara , Robinson Christopher 
Published: October 2008

Abstract
Diatom communities in alpine-zone streams of the Tatra National Park and the Swiss National Park were heterogeneous with respect to species richness, abundance, Shannon diversity index, and ecological preference. Two groups of diatoms were distinguished. Group 1, inhabited streams in the upper Gąsienicowa Valley (Tatra Mts) and Macun Lakes region (Alps), and had high species richness and Shannon diversities (especially in the Tatra Mts streams) but low abundances. The most abundant and common diatoms were Psammothidium helveticum, Diatoma mesodon, Aulacoseira alpigena, Achnanthidium minutissimum, Psammothidium subatomoides, Psammothidium marginulatum, and Gomphonema parvulum. Group 2 inhabited Tatra Mts streams in the Five Polish Lakes Valley and lower Gąsienicowa Valley. Diatoms were highly abundant but species richness and Shannon diversities were relatively low. The most abundant were Achnanthidium minutissimum, Diatoma mesodon, Fragilaria capucina gracilis group and Tabellaria flocculosa. There was no clear difference between the diatom communities of the outlet streams of upper lakes and the inlet streams of adjacent downstream lakes. The high abundance of diatoms in the streams of the Tatra Mts suggests recent ecosystem changes related to lake eutrophication and partly by weather anomalies resulting from climate change.
Lead and cadmium content in the meat tissues of fish from water ecosystems in the vicinity of a pesticide tomb
Authors: Skibniewska Krystyna , Guziur Janusz , Marzec Zbigniew , Zaręba Stanisław , Grzybowski Mirosław , Szarek Józef 
Published: October 2008

Abstract
Lead and cadmium levels were determined in the meat tissues of roach, bream, and carp netted in a lake and in fish ponds threatened by a pesticide tomb and in control basins in northeastern Poland. Concentrations in roach ranged from 20 to 124 μg kg-1 of Pb and from 1 to 19 μg kg-1 of Cd. In bream they were from 4 to 280 μg kg-1 of Pb and 2 to 28 μg kg-1 of Cd, while in carp they were from 9 to 82 μg kg-1 of Pb and 2 to 260 μg kg-1 of Cd. The metal concentrations were low; no result exceeded admissible residue levels set forth by Polish law, and no evident contamination of fish by leakage from the pesticide tomb was detected.
Comments on the diet of Asplanchna priodonta (Gosse, 1850) in the Dobczycki dam reservoir on the basis of field sample observations
Authors: Pociecha Agnieszka , Wilk-Woźniak Elżbieta 
Published: October 2008

Abstract
During a monitoring programme the diet composition of Asplanchna priodonta was studied. Samples were collected every month from the deepest part of the Dobczycki dam reservoir (Southern Poland). The diet of A. priodonta, which included colonial cyanobacteria, diatoms, dinoflagelates and protozoa, indicated that it is both a grazer and a predator. These results support the hypothesis that A. priodonta is an opportunistic feeder. Additionally these results include the first observations of the protozoan Tintinnopsis sp. as a food source of Asplanchna.
Chemometric exploration of sea water chemical component data sets with missing elements
Authors: Smoliński Adam , Falkowska Lucyna , Pryputniewicz Dorota 
Published: October 2008

Abstract
The results of the application of chemometric methods, such as principal component analysis (PCA) and its generalization for N-way data, the Tucker3 model, for the analysis of an environmental data set are presented. The analyzed data consists of concentration values of chemical compounds of organic matter, and their transformed products, in a short-term study of a sea water column measured at the Gdańsk Deep (φ = 55°1'N, λ = 19°10'E).
The main goal of this paper is to present improved approaches for exploration of data sets with missing elements, based on the expectation-maximization (EM) algorithm. The most common methods for dealing with missing data, generally consisting of setting the missing elements to zero or to mean values of the measured data, are often unacceptable as they destroy data correlations or influence interpretation of relationships between objects and variables. The EM algorithm may be built into different computational procedures used for exploratory analysis (i.e. EM/PCA or EM/TUCKER3).
New data on the biology of the introduced exotic nematode Anguillicola crassus Kuwahara, Niimi et Itagaki, 1974 in the eel Anguilla anguilla in Lake Wdzydze (Polish waters)
Authors: Rolbiecki Leszek 
Published: October 2008

Abstract

Anguillicola crassus Kuwahara, Niimi et Itagaki, 1974 is an Asian parasitic nematode that was introduced to Europe and inhabits the swim bladder of eels. In the 2002-2005 period, 237 eels, Anguilla anguilla (Linnaeus, 1758), from Lake Wdzydze were examined for the occurrence of the nematode. 79.3% of the fish were infected, at a mean intensity of 7.2 nematodes per fish. Morphological measurements of the observed A. crassus are presented. This is the first published report of A. crassus in eels from Lake Wdzydze.
The evaluation of Cr, Ni, Cu, and Co contents in bottom sediments of the Supraśl River and its tributaries
Authors: Skorbiłowicz Elżbieta , Skorbiłowicz Mirosław 
Published: October 2008

Abstract
The aim of this study was to evaluate the total and soluble forms of Cr, Ni, Cu, and Co contents in bottom sediments of the Supraśl River and its tributaries. Studies were carried out in August 2005 and March 2006. The total contents of metals were determined, following the digestion of the sediments in nitric acid in a MARS 5 closed microwave system. Soluble forms of metals were extracted with 1 mol dm-3 HC1 at the ambient temperature. The bottom sediments of the Supraśl and its tributaries are slightly contaminated with chromium. Copper, nickel, and cobalt occur mainly at a geochemical background level. A positive linear correlation between total forms of metal contents and their soluble forms was found.
Establishing reference conditions for Polish lakes - preliminary results
Authors: Soszka Hanna , Kolada Agnieszka , Gołub Małgorzata , Cydzik Dorota 
Published: October 2008

Abstract
Establishing reference conditions is essential for performing ecological status assessments of surface waters according to the EU Water Framework Directive. Ecological status is described as the deviation from undisturbed (reference) conditions. This paper presents the process of establishing preliminary reference values for chlorophyll a, total phosphorus, and Secchi disc readings in different types of Polish lakes. This was done by selecting potential reference lakes and performing statistical analysis of the values of the main eutrophication parameters. The preliminary reference values for total phosphorus, chlorophyll, and Secchi disc depth were defined as 0.033 mgP dm-3, 3.75 μg dm-3, and 3.6 m for stratified lakes, and 0.048 mgP dm-3, 5.80 μg dm-3, and 2.5 m. for polymictic lakes, respectively.
Assessing flood risk and detecting changes of salt water inflow in a coastal micro-tidal brackish marsh using GIS
Authors: Urbański Jacek , Ślimak Agata 
Published: October 2008

Abstract
In order to assess changes in salt water inflow and potential flood risks due to sea level rise in a micro-tidal Beka brackish marsh on the Polish Baltic Coast GIS was used. Such wetlands are important elements of coastal zone natural environments. Creating a geodatabase within a GIS system makes it possible to carry out broad analyses of complex systems, such as coastal wetlands. The results indicate that a 40 cm sea-level rise would considerably increase the frequency of flooding in the investigated area, in part because of the small range of the annual sea level oscillations there. A map of the index of changes in saltwater inflow, created with the help of cost-weighted distance (functions), shows that changes which have occurred along the shore, consisting of filling in the drainage channel outlets, have likely had a significant impact on the vegetation of the area.
Preparation and characterization of catalyst mix Fe-Co/MgO for carbon nanotubes growth
Authors: Steplewska Anna , Jedrzejewski Roman , Borowiak-Palen Ewa 
Published: October 2008

Preparation and characterization of catalyst mix Fe-Co/MgO for carbon nanotubes growth
Fe-Co/MgO is one of the most common catalyst mix applied to carbon nanotubes (CNTs) growth in chemical vapor deposition process. Therefore, here we present detailed study on the preparation and characterization of Fe-Co/MgO. The precursors of Fe and Co are iron (II) acetate and cobalt acetates, correspondingly. The molar ratio of the catalyst mix is Fe:Co:MgO=1:1:100. Initially, thermogravimetric analysis (TGA) of the mixture was performed. TGA analysis of it indicated the stepwise mass losses which pointed out the crucial thermal conditions for the changes in the elemental composition, morphology, crystallographic structure and vibrational properties. In current state of the art the lowest growth temperature for singlewalled carbon nanotubes is 550°C in CVD technique and here the characterization of the catalyst mix strongly suggest that this temperature can be decreased what would enhance the compatibility of CNT growth with current complementary metal-oxide-silicon (CMOS) technology for CNTs-based nanoelectronics. The morphology, crystallographic structure, elemental composition of the samples and its spectroscopic properties were performed via high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD) and Infrared spectroscopy (IR), respectively.