Bed sediments and geomorphological processes in high-gradient streams based in flysch of the Moravskoslezské Beskydy Mts.

Lithology of bed sediments in high-gradient streams may aff ect grain-size parameters and, thus, bed morphology and sediment transport dynamics. Flysch character of bedrock with alternation of resistant sandstones and less-resistant claystones influenced geomorphic processes and bed sediments in Beskydian headwater channels. Generally, claystone members supplied streams by higher amounts of relatively fi ner clastic material. On the contrary, channels located in sandstone members (e.g., Godula Member) were prone to occurrence of exposed bedrock due to signifi cantly lower sediment supply, except channel-reaches with evidence of debris-fl ow activity. Obtained trends of evaluated grain-size parameters (D90 and nominal index) in the stream longitudinal profi les pointed up on infl uence of claystone ratio in bed sediments and a character of sediment inputs. Signifi cant presence of claystones in bed sediments of selected streams led to decrease in D90 percentile and nominal index Dn of bed surface material. On the other hand, sandstone sediment supply in high-gradient streams underlaid by the middle part of the Godula Member did not show downstream coarsening or fi ning of bed sediments within stream longitudinal profi les and higher values of grain-size parameters were observed. Lithology of bed sediments in high-gradient streams may affect grain-size parameters and, thus, bed morphology and sediment transport dynamics. Flysch character of bedrock with alternation of resistant sandstones and less-resistant claystones influenced geomorphic processes and bed sediments in Beskydian headwater channels. Generally, claystone members supplied streams by higher amounts of relatively finer clastic material. On the contrary, channels located in sandstone members (e.g., Godula Member) were prone to occurrence of exposed bedrock due to significantly lower sediment supply, except channel-reaches with evidence of debris-flow activity. Obtained trends of evaluated grain-size parameters (D90 and nominal index) in the stream longitudinal profi les pointed up on influence of claystone ratio in bed sediments and a character of sediment inputs. Significant presence of claystones in bed sediments of selected streams led to decrease in D90 percentile and nominal index Dn of bed surface material. On the other hand, sandstone sediment supply in high-gradient streams underlaid by the middle part of the Godula Member did not show downstream coarsening or fining of bed sediments within stream longitudinal profiles and higher values of grain-size parameters were observed

Stream-bed sediments as indicators of sediment sources in flysh areas

The character of bed sediments reflects fluvial processes and the dynamics of material transport in fluvial (dis)continuum systems. The approach in this study was based on the measurement of the five largest boulders located within a channel, and on the observation of changes in their size in the longitudinal profi le of headwater streams Kobylská and Pulčínský potok. All three axes (dimensions) of the five largest boulders were measured at 10 ± 1m intervals of the longitudinal profile. The resulting trends in a particle-size index reflect the character of sediment delivery into the channel segment. The largest boulders were observed in channel sections with a strong interaction of slope processes. But local lithological conditions affect changes of the mean value of the particle-size index of the largest boulders. The role of slope processes can be accentuated by the presence of uniform sandstone lithology of the studied bed particles. In the lithology built by claystone layers the role of slope processes has problematic identification. The main reason is erodible character of claystone layers which affects sediment supply of finer particles from adjacent slopes into the channel segment.The character of bed sediments reflects fluvial processes and the dynamics of material transport in fluvial (dis)continuum systems. The approach in this study was based on the measurement of the five largest boulders located within a channel, and on the observation of changes in their size in the longitudinal profi le of headwater streams Kobylská and Pulčínský potok. All three axes (dimensions) of the five largest boulders were measured at 10 ± 1m intervals of the longitudinal profile. The resulting trends in a particle-size index reflect the character of sediment delivery into the channel segment. The largest boulders were observed in channel sections with a strong interaction of slope processes. But local lithological conditions affect changes of the mean value of the particle-size index of the largest boulders. The role of slope processes can be accentuated by the presence of uniform sandstone lithology of the studied bed particles. In the lithology built by claystone layers the role of slope processes has problematic identification. The main reason is erodible character of claystone layers which affects sediment supply of finer particles from adjacent slopes into the channel segment

Effect of instream wood on channel morphology and sedimentology: an example of the meandering Odra River

Instream wood is a natural phenomenon that signifi cantly influences a function of the fluvial system in forested river basins and represents a natural part of this system. However, the majority of these relatios between instream wood and fluvial ecosystems were investigated in mountain streams or gravel-bed rivers and we are lacking field data from lowland meandering rivers. This study deals with the complex assessment of instream wood on morphology and sediment parameters including the content of organic material at spatially detailed scale of the selected bend of the Odra River. Within the site of interest (66.5 river km), 12 instream wood pieces were identified (lenght ≥ 1 m, diameter ≥ 10 cm). Their presence significantly affected river morphology, when they were the main initiator of pool formation. In total, 28 samples of surface bed sediments were collected from the thalweg, bars and lateral pool. In laboratory, samples were subjected to grain size analysis (sieving method) and loss on ignition (LOI) to obtain content of organic matter. The majority of bed sediment samples were coarse grained and these samples were located in the thalweg. The main component of these samples is gravel, often supplemented with admixtures of finer fractions. The analysis of data did not show the effect of instream wood on the deposition of organic matter in bed sediments. One of the reasons may be the presence of coarse grained material which generally contains a small amount of organic matter.Instream wood is a natural phenomenon that signifi cantly influences a function of the fluvial system in forested river basins and represents a natural part of this system. However, the majority of these relatios between instream wood and fluvial ecosystems were investigated in mountain streams or gravel-bed rivers and we are lacking field data from lowland meandering rivers. This study deals with the complex assessment of instream wood on morphology and sediment parameters including the content of organic material at spatially detailed scale of the selected bend of the Odra River. Within the site of interest (66.5 river km), 12 instream wood pieces were identified (lenght ≥ 1 m, diameter ≥ 10 cm). Their presence significantly affected river morphology, when they were the main initiator of pool formation. In total, 28 samples of surface bed sediments were collected from the thalweg, bars and lateral pool. In laboratory, samples were subjected to grain size analysis (sieving method) and loss on ignition (LOI) to obtain content of organic matter. The majority of bed sediment samples were coarse grained and these samples were located in the thalweg. The main component of these samples is gravel, often supplemented with admixtures of finer fractions. The analysis of data did not show the effect of instream wood on the deposition of organic matter in bed sediments. One of the reasons may be the presence of coarse grained material which generally contains a small amount of organic matter

Effect of lithology and morphology of high-gradient channels on bed sediments: a case study of the Kobylská Stream (Vsetín highlands, Czech Republic)

High-gradient streams are integral parts of the fluvial systems, which connect the mountainous landscapes with lowland rivers in the sense of water and sediment transport. We analysed downstream grain-size characteristics of bed sediments and sphericity of grains with respect to the local flysch lithology and channel geometry in the 5.4 km long reach of the high-gradient Kobylská Stream (the Vsetín highlands, Outer Western Carpathians, Czech Republic). Results showed a high variability of bed-sediment sizes in the longitudinal course of the Kobylská stream. This condition is given by the occurrence of anthropogenic impact in the studied channel (local bank stabilisations, grade-control structures) and lateral sediment input from the adjacent landslides and bank failures. The lithology of the flysch nappe structure of the basin significantly influenced variations of bed sediment grain-sizes. Different bedrock resistance resulted into inverse correlation between the local river gradient and related bed grain-sizes. Especially the mudstone bedrock layers had significant impact on the fining of bed sediment in the upper steep part of the basin (D50 ≤ 40 mm) and by contrast, sandstone bedrock caused the coarsening of the bed sediment in the middle and lower parts (D50 up to 50 mm) characterised by lower bed gradients.High-gradient streams are integral parts of the fluvial systems, which connect the mountainous landscapes with lowland rivers in the sense of water and sediment transport. We analysed downstream grain-size characteristics of bed sediments and sphericity of grains with respect to the local flysch lithology and channel geometry in the 5.4 km long reach of the high-gradient Kobylská Stream (the Vsetín highlands, Outer Western Carpathians, Czech Republic). Results showed a high variability of bed-sediment sizes in the longitudinal course of the Kobylská stream. This condition is given by the occurrence of anthropogenic impact in the studied channel (local bank stabilisations, grade-control structures) and lateral sediment input from the adjacent landslides and bank failures. The lithology of the flysch nappe structure of the basin significantly influenced variations of bed sediment grain-sizes. Different bedrock resistance resulted into inverse correlation between the local river gradient and related bed grain-sizes. Especially the mudstone bedrock layers had significant impact on the fining of bed sediment in the upper steep part of the basin (D50 ≤ 40 mm) and by contrast, sandstone bedrock caused the coarsening of the bed sediment in the middle and lower parts (D50 up to 50 mm) characterised by lower bed gradients

Conditions of sediment transport and accumulation in man-affected Beskydian rivers: case study of the Morávka and Mohelnice rivers confluence

This paper summarizes results of grain-size distribution of gravel bars and transport conditions in the context of sediment sources in the confl uence area of the Morávka and Mohelnice rivers (Moravskoslezské Beskydy Mts). We deal with a hypothesis that general changes of grain-size distribution of gravel bars are controlled by disconnection in sediment flux in the Morávka River and, by contrast, that higher sediment delivery is related to the Mohelnice river basin. The second focus is the evaluation of fluvial transport parameters of a channel influenced by control works and sediment mining. Bed load transport research was conducted with the application of BAGS (Bedload Assessment for Gravel-bed Streams) spreadsheet-based program. Sediment analysis of the channel confluence showed limited sediment supply character indicated by coarser sediment delivery from the Morávka River. This fact is related to the effect of hungry water caused mainly by the Morávka Reservoir. On the other hand, the Mohelnice River displayed trends of relatively higher sediment delivery without potential disconnectivities in sediment flux. Results of this analysis brought an insight into a potential scheme of the future development of the studied reaches. We suppose preservation of recent trends in case of the occurrence of signifi cant changes in land use or watershed management.This paper summarizes results of grain-size distribution of gravel bars and transport conditions in the context of sediment sources in the confl uence area of the Morávka and Mohelnice rivers (Moravskoslezské Beskydy Mts). We deal with a hypothesis that general changes of grain-size distribution of gravel bars are controlled by disconnection in sediment flux in the Morávka River and, by contrast, that higher sediment delivery is related to the Mohelnice river basin. The second focus is the evaluation of fluvial transport parameters of a channel influenced by control works and sediment mining. Bed load transport research was conducted with the application of BAGS (Bedload Assessment for Gravel-bed Streams) spreadsheet-based program. Sediment analysis of the channel confluence showed limited sediment supply character indicated by coarser sediment delivery from the Morávka River. This fact is related to the effect of hungry water caused mainly by the Morávka Reservoir. On the other hand, the Mohelnice River displayed trends of relatively higher sediment delivery without potential disconnectivities in sediment flux. Results of this analysis brought an insight into a potential scheme of the future development of the studied reaches. We suppose preservation of recent trends in case of the occurrence of signifi cant changes in land use or watershed management

IDENTIFIKACE (DIS)KONEKTIVIT VODNÍCH TOKŮ ZA VYUŽITÍ MAKROGRANULOMETRICKÉ ANALÝZY KORYTOVÝCH SEDIMENTŮ (MORAVSKOSLEZSKÉ BESKYDY)

This paper brings evidence on sediment distribution trends in longitudinal profiles of Beskydian high gradient streams. High gradient streams play an important role in the context of fluvial (dis)continuum as they represent a source of sediment for downstream parts of catchments. The main instrument in the identification of river basin (dis)connectivity was grain-size analysis and fluvialgeomorphological mapping. In addition, bedload material transport force was computed for sections in the vicinity of gauging station. The research comprised the study areas of the Býčinec Basin, the Velký Lipový Basin and the Malá Ráztoka Basin

Validation of distinct pathogenic patterns in a cohort of membranoproliferative glomerulonephritis patients by cluster analysis

Background: A novel data-driven cluster analysis identified distinct pathogenic patterns in C3-glomerulopathies and immune complex-mediated membranoproliferative glomerulonephritis. Our aim was to replicate these observations in an independent cohort and elucidate disease pathophysiology with detailed analysis of functional complement markers. ----- Methods: A total of 92 patients with clinical, histological, complement and genetic data were involved in the study, and hierarchical cluster analysis was done by Ward method, where four clusters were generated. ----- Results: High levels of sC5b-9 (soluble membrane attack complex), low serum C3 levels and young age at onset (13 years) were characteristic for Cluster 1 with a high prevalence of likely pathogenic variations (LPVs) and C3 nephritic factor, whereas for Cluster 2-which is not reliable because of the small number of cases-strong immunoglobulin G staining, low C3 levels and high prevalence of nephritic syndrome at disease onset were observed. Low plasma sC5b-9 levels, decreased C3 levels and high prevalence of LPV and sclerotic glomeruli were present in Cluster 3, and patients with late onset of the disease (median: 39.5 years) and near-normal C3 levels in Cluster 4. A significant difference was observed in the incidence of end-stage renal disease during follow-up between the different clusters. Patients in Clusters 3-4 had worse renal survival than patients in Clusters 1-2. ----- Conclusions: Our results confirm the main findings of the original cluster analysis and indicate that the observed, distinct pathogenic patterns are replicated in our cohort. Further investigations are necessary to analyse the distinct biological and pathogenic processes in these patient groups

C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy

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Ekonomická přidaná hodnota

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Ekonomická fakulta. Katedra (154) financ

Ecosystem Services of Large Wood: Mapping the Research Gap

It is well known that large wood affects geomorphic processes and functions in rivers. It enhances the quality of the habitat but it can also cause a threat to the population. These processes and functions of the environment can be transformed into ecosystem (dis)services, which represent direct or indirect (dis)benefits that the society obtains from nature. The goal of this paper was to describe the current relations between large wood and ecosystem services and map the related knowledge gaps. Firstly, we conducted a systematic literature review that was elaborated according to the six-stage and PRISMA protocols and workflow diagram. We found 499 papers; however, only 137 were eligible for the following analyses. Secondly, we made a transformation of research information from the articles (n = 135) into ecosystem services. The highest number of ecosystem services detected in the articles belonged to the regulation and maintenance section (n = 126), followed by the provisioning (n = 15) and cultural (n = 11) sections. The detected classes with the highest frequency of studies were specific habitat creation and increased channel heterogeneity. The findings show that the number of research papers on this topic is still insufficient; however, anaylzing ecosystem services could be useful to advocate the presence of large wood in the rivers