Stream Courses Research Articles

Rainfall Induced Rock-Fall Debris Avalanche in October 2010, at Kwande Local Government Area of Benue State, Nigeria

Abstract This study explains the causes and the mechanism of the landslide occurrence at Kwande local Government Area of Benue, Nigeria in 2010. Although there was no fatality or any damage in the area, a large area of farmland was destroyed, trees were uprooted and a normal stream course was also disturbed. To study and understand the landslide event, a combination of geotechnical investigations and statistical data were used. These parameters were applied to a numerical model to simulate the causes of the landslide. Results of the geotechnical investigations made on samples taken from the area, showed average maximum dry density value of 1.6kg/m3, and average optimum moisture content value of 14%, hence the low to moderate density is indicative of a soil that can easily disperse. Also the triaxial compression test showed an angle of internal friction and cohesion values averaging around 14.82° and 25kPa respectively, and these low values indicate that the shear strength of the soil was reduced, due to the combined effect of increase in slope gradient, and high precipitation intensity which increased to a monthly value of 145mm before the landslide. The simulation result showed that the factor of safety value was 1.158, which is still close to the value for an incipient failure. Hence the results shown can be used in predicting the mechanisms and areas of possible landslides, as well as the causes of such soil deformations, and as such, safety measures could be taken against the reoccurrence of landslides in the area.

Impact of Long-Term Application of Domestic Sewage Water on Soil Properties Around Hubli City in Karnataka, India

The effects of application of domestic sewage water for over four decades on physical, chemical and biological properties of soils were studied at three sites in Gabbur, Mavanur and Katnur villages near Hubli city in North Karnataka, India. Long-term use of sewage irrigation improved soil physical properties in terms of decrease in bulk density and dispersion index and increase in aggregate stability and water holding capacity compared to the unirrigated check. Despite long-term irrigation with sewage water with an EC of >1 dS m−1, the EC of soils was low (0.20–0.45 dS m−1). An increase of one-and-half to two times in organic carbon content, available N, P, K and S, in the sewage irrigated soils was observed compared to soils not irrigated with sewage. However, the available Zn, Fe, Cu and B increased only slightly with the exception of Mn which increased substantially. In general there was a decreasing trend of organic carbon, available N, P, K and S with distance away from the stream course. Despite no heavy metals in sewage water, they were detected in soils but not in toxic levels. There were 94, 80 and 60 % more bacteria, fungi and actinomycetes, respectively, in sewage irrigated soils over the non-irrigated soils. Further, the coliform bacteria (E. coli) were observed in soil samples, suggesting fecal contamination.

Hexa(methoxymethyl)melamine: An Emerging Contaminant in German Rivers.

Hexa(methoxymethyl)melamine (HMMM)-containing resins are used in the production of coatings and plastics for cans, coils, and automobiles. A previous study demonstrated that this compound was associated with acute toxic effects on daphnia. This study presents the first compiled data on the occurrence of HMMM as an emerging contaminant in German rivers. The compound occurred in 60 of 117 water samples from three river systems, with concentrations ranging between < 10 and 880 ng/L. Based on water concentrations and river flow on the day of sampling, the loads of HMMM were calculated for two rivers. The spatial distribution patterns of the loads showed large variations and did not follow clear trends along the stream course. These variations were attributed to effective removal processes, leading to sudden load decreases within short flow distances. The data suggest that HMMM could be discharged to the investigated rivers with wastewaters from the automotive industry and related branches.

Rediscovery, phytogeography and conservation status of Leptodermis riparia Parker (Rubiaceae) in Western Himalaya, India

Leptodermis riparia Parker (Rubiaceae) is rediscovered after a gap of 90 years from its Type locality in eastern part of Uttarakhand, Western Himalaya. In addition, we recorded two new localities of this species in the state. All the three populations were found along stream courses especially on rocky substrates rich in limestone. The Type locality for this species was devastated due to severe floods of 2013. In this article, we have presented description, habitat characteristics, phytogeography and conservation status of L. riparia in the Western Himalaya.

Do adult snails in headwater streams make upstream migrations to compensate for spate-induced washout? A test using three populations of a tropical caenogastropod

Stream snails are known to exhibit upstream migration in temperate and tropical regions (see reviews by Huryn & Denny, 1997; Kappes & Haase, 2012). This behaviour can be driven by a variety of factors depending on species and circumstances, including the search for food, predator avoidance and compensation for washout or catastrophic drift during spates (e.g. Schneider & Frost, 1986; Schneider & Lyons, 1993; Snider & Gilliam, 2008). Recolonization of upstream habitats via migration can replenish losses due to spate-induced washout (Kopp, Jeschke & Gabriel, 2001) and could be an important mechanism contributing to population persistence (Speirs & Gurney, 2001; Pachepsky et al., 2005). Upstream migration may also be a mechanical consequence of snails orientating themselves to reduce hydrodynamic drag (Huryn & Denny, 1997; Covich, 2010). Within a species, migration patterns vary in relation to individual size and growth (e.g. Schneider & Lyons, 1993; Shigemiya & Kato, 2001; Snider & Gilliam, 2008; BlancoLibreros & Arroyave-Rincon, 2009). Upstream migrations of snails in tropical and subtropical streams have been mostly documented in amphidromous Neritidae (Blanco & Scatena, 2005, and references therein), which have plankotrophic larvae that require saline conditions for development. Juveniles must therefore migrate upstream from estuaries to adult habitats where they mature and breed (McDowall, 2007; Crandall, Taffel & Barber, 2010; Gorbach et al., 2012). The caenogastropod pachychilid Sulcospira hainanensis (Brot, 1872) is widespread in tropical streams in southern China (including Hong Kong, Guangdong and Hainan) and northern Vietnam (Kohler & Glaubrecht, 2001; Yeung & Dudgeon, 2014b). Sulcospira hainanensis is not amphidromous; it spends its entire life in fresh water and larvae are incubated in a cephalic brood pouch prior to their release in the form of miniature adults (Kohler & Glaubrecht, 2001). Wet-season declines in abundance have been recorded in this species, likely due to washout during spates (as high as 85%; Yeung & Dudgeon, 2014b). Upstream migration may therefore be necessary to compensate for this downstream displacement, which might otherwise result in long-term decline in snail densities in the upper courses of streams. There are few studies of migration by non-amphidromous caenogastropds in tropical streams, but Cochliopina tryoniana (Pilsbry) (Hydrobiidae) in Costa Rican streams exhibits upstream migratory behaviour, moving at rates of up to 110 m d (Schneider & Lyons, 1993). These streams receive frequent spates in the wet season, analogous to those in Hong Kong, and we consider it likely that the upstream migration of C. tryoniana is a compensatory response to downstream washout during this period, rather than having the life-history role seen in freshwater neritids (Schneider & Lyons, 1993). We hypothesized that S. hainanensis would show upstream migrations as a compensatory response to spate-induced washout. This was tested using a year-long mark-and-recapture study of three populations in Hong Kong. The study populations inhabited second-order stream at Tai Po Kau (TPK), and third-order streams at Pak Ngau Shek (PNS) and Shing Mun (SM) in the mainland New Territories of the Hong Kong Special Administrative Region of the People’s Republic of China (Yeung & Dudgeon, 2013: fig. 1). The TPK site (elevation: 180 m) was situated at mid-altitude and other sites (PNS: 110 m; SM: 300 m) in the lower half in their respective drainage basins. These sites were thus not close to the uppermost distributional limits of snails, which allowed the detection of any active upstream migration. Snails were present both upstream, and at various distances downstream of the study reaches, and physical conditions upand downstream were similar. Hong Kong has a tropical monsoonal climate, with the wet season (May to August) in 2011 (the year when the study was conducted) receiving 42% (1,007 mm) of the mean annual rainfall of 2,399 mm, which is typical of the seasonal pattern of precipitation (Hong Kong Observatory, 2011). Spates (.50 mm rainfall in 1 d) were frequent during this period (Hong Kong Observatory, 2011). The study sites encompassed a wide range of canopy closure (PNS: 40%; TPK: 80%; SM: 90%), with consequent differences in algal food availability (Yeung & Dudgeon, 2014a). Most other physical characteristics were similar in these streams, where the waters were slightly acidic and welloxygenated (see Yeung & Dudgeon, 2013; Table 1). Therefore, the sites chosen broadly represent the stream environment that the snails inhabit in Hong Kong. Monthly collections of 80–100 S. hainanensis individuals were made from January 2011 to January 2012 (except July 2011) along a 20-m study reach at each of the three sites. They were marked individually by uniquely identifiable bee tags (Opalith Numberplates for Queens, Item 112,902, Swienty A/S Company, Sonderborg, Denmark) attached to the shell with Aron Alpha Instant Glue super glue gel (Toagosei America Inc., West Jefferson, United States). Individuals ,1.5 mm aperture width

Chemical assessment and fractionation of some heavy metals and arsenic in agricultural soils of the mining affected Drama plain, Macedonia, northern Greece.

The concentration and chemical fractionation of some heavy metals (Mn, Pb, Zn, Cu, Cd) and As in agricultural soils of the western Drama plain (northern Greece) were determined using inductively coupled plasma-mass spectrometry (ICP-MS) technique. Drama plain constitutes the recipient of the effluents from Xiropotamos stream, which passes through the abandoned "25km Mn-mine" place. Results showed that soils were found to have elevated concentrations of potentially harmful elements which are mainly associated with Mn mineralization. Peak total concentrations (in mgkg(-1)) of 130,013 for Mn, 1996 for Pb, 2140 for Zn, 147 for Cu, 28 for Cd, and 1077 for As were found in sampling points close and along both sides of the Xiropotamos stream, as a result of downstream transfer and dispersion of Mn mine wastes via flooding episodes. Contaminated sites are important sources of pollution and may pose significant environmental hazards for terrestrial and aquatic ecosystems. The geochemical influence of the mine wastes as a source of soil pollution is substantially reduced in sites 200m remote of the Xiropotamos stream course. The chemical partitioning patterns indicated that the potential for Mn, Pb, Zn, Cu, Cd, and As remobilization and bioavailability is low, as most of these elements were present in the residual and/or the more stable Mn- and Fe-hydroxide fractions. The partitioning in significant percent (14-25%) of Cd with the weakly bound exchangeable/carbonate fraction indicated that this metal could be highly mobile as well as bioavailable in the studied contaminated soils and this could be concern to human health.

Plasticity in the diet of an insectivorous Characin from a coastal stream of south-east Brazil: effects of riparian canopy cover in the diet and prey selectivity

Event Abstract Back to Event Plasticity in the diet of an insectivorous Characin from a coastal stream of south-east Brazil: effects of riparian canopy cover in the diet and prey selectivity Paula B. Mazzoni1* and Rosana Mazzoni1 1 UERJ, Ecology, Brazil Riparian zones are intimately linked to aquatic ecosystems and affect a number of processes including the maintenance of many fishes species that feed directly on insect prey of both allo and autochtonous origin. Mimagoniates microlepis is a Glandulocaudinae species whose diet is broadly based on unsects. Registers mentioned that Mimagoniates species are generally opportunistic foragers, consuming prey approximately in proportion to what is available in the environment. Coastal streams from Mata Atlântica in the east cost of South America has been suffering drastic losses of natural cover because of forest cutting to supply the growing demands for food, development of agricultural fields, intensive cultivation of sugar cane and soya beans. In the present study we aimed to access how much the availability of insect prey changes along the stream course of a coastal stream from Mata Atlântica (southeast Brazil). We addressed if changes in the availability of prey insects are reflected in the diet of Mimagoniates populations occurring in different sites along the stream. We sampled prey availability and fishes at five sites with different degrees of canopy coverture (shaded vs. non shaded sites). We found that prey availability changes according to physical environmental variables (coverture, water velocity and substratum). Although adaptable to prey availability, relative importance of different insect groups changed in the diet of individuals according to sampling site, M. microlepis was not registered in sites without canopy coverture and allochthonous insect prey. References BARRETO, Almir P.; ARANHA, José M. R.. Alimentação de quatro espécies de Characiformes de um riacho da Floresta Atlântica, Guaraqueçaba, Paraná, Brasil. Revista Brasileira de Zoologia, Paraná, v.23. BRAGA, Almir P.; ARANHA, José Marcelo Rocha; VITULE, Jean Ricardo. Reproduction Period of Mimagoniates microlepis, from an Atlantic Forest Stream in Southern Brazil. Keywords: Stream, Mata Atlântica, rain forest, feeding ecology, Allochthonous matter Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Poster Presentation Topic: Ecology, Conservation and Invasive Species Citation: Mazzoni PB and Mazzoni R (2015). Plasticity in the diet of an insectivorous Characin from a coastal stream of south-east Brazil: effects of riparian canopy cover in the diet and prey selectivity. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.FMARS.2015.03.00210 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 07 Dec 2015; Published Online: 07 Dec 2015. * Correspondence: Mrs. Paula B Mazzoni, UERJ, Ecology, Rio de Janeiro, 20550013, Brazil, paulabmazzoni@yahoo.com.br Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Paula B Mazzoni Rosana Mazzoni Google Paula B Mazzoni Rosana Mazzoni Google Scholar Paula B Mazzoni Rosana Mazzoni PubMed Paula B Mazzoni Rosana Mazzoni Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

From Description to Process

From Description to Process

Disappearance of a dominant bosque species: screwbean mesquite (Prosopis pubescens)

Historic surveys record screwbean mesquite (Prosopis pubescens) as widespread and dominant within upland riparian communities of the U.S. Southwest. I compared herbarium records and published surveys with surveys I conducted throughout the former range of P. pubescens. I found that this species has disappeared from 53% of its former range and has declined in density at eight of nine sites compared. Of 112 sites surveyed, only Ash Meadows National Wildlife Refuge has dense groves of P. pubescens over a large area. Prosopis pubescens remains in protected areas but not in urbanized areas. Declines of southwestern riparian species such as cottonwood and willow are well documented, but this is the first example of a declining species that is typically considered drought tolerant and is often found farther away from the stream course. Human alteration of rivers is therefore likely to be influencing plant communities as far away as a kilometer from the river itself.

Analyses of optical images and radar data reveal structural features and predict groundwater accumulations in the central Eastern Desert of Egypt

The North African Sahara is currently dominated by arid to hyperarid climate. In the central part of the Eastern Desert of Egypt, Wadi Matula is a dry stream course much like those in the rest of the Sahara. It covers an area of about 7,500 km2. Radarsat-1 images, Shuttle Radar Topography Mission (SRTM), and Advanced Land Observing Satellite (ALOS)/Phased Array type L-band Synthetic Aperture Radar (PALSAR) data revealed paleodrainage systems and fault/fracture zones. Its trends display cross-cutting relationships. Interrupted surface runoff connections are inferred from block movements, tectonic capture processes, diverted valleys, and paleodrainage. The movements of the blocks led to newly formed drainage and caused disturbances in drainage orientations, topography, fractures, and stream density. Paleodrainage and the more recent drainage lines are superposed on weakness zones of major fractures and faults. These zones facilitated the hydrologic processes that caused erosion and downcutting. The intersection points of paleochannel courses, fracture/fault systems, and active streams must have increased the possibilities of groundwater accumulations. Accordingly, several exploration wells are suggested, which they represent the best abstraction sites of groundwater potentials. These predicted sites are consistent with the high potential zone of the groundwater prospect map. Thick fluvial deposits support that past pluvial events recharged the underlying aquifers. It is concluded that locations of paleodrainage, fractures/faults, and stream intersections are the best sites for groundwater resources; thus, radar images are powerful tools for mapping multi-temporal near-surface features in arid regions.

Inner gorge–slot canyon system produced by repeated stream incision (eastern Alps): Significance for development of bedrock canyons

Many inner bedrock gorges of the Alps show abrupt downstream changes in gorge width, as well as channel type and gradient, as a result of epigenetic incision of slot canyons. Many slot canyons also are associated with older gorge reaches filled with Quaternary deposits. The age of slot canyons and inner bedrock gorges, however, commonly is difficult to constrain. For the inner-bedrock gorge system of the Steinberger Ache catchment (eastern Alps), active slot canyons as well as older, abandoned gorge reaches filled with upper Würmian proglacial deposits record three phases of gorge development and slot–canyon incision. A 234U/230Th age of cement of 29.7±1.8ka in fluvial conglomerates onlapping the flank of an inner gorge fits with late Würmian valley-bottom aggradation shortly before pleniglacial conditions; in addition, the age indicates that at least the corresponding canyon reach must be older. During advance of ice streams in the buildup of the Last Glacial Maximum (LGM), the catchment was blocked, and a proglacial lake formed. Bedrock gorges submerged in that lake were filled with fluviolacustrine deposits. During the LGM, the entire catchment was overridden by ice.During post-glacial reincision, streams largely found again their preexisting inner bedrock canyons. In some areas, however, the former stream course was ‘missed’, and a slot canyon formed. The distribution of Pleistocene deposits, the patterns of canyon incision, and the mentioned U/Th cementation age, however, together record a further discrete phase of base-level rise and stream incision well before the LGM. The present course of Steinberger Ache and its tributaries is a patchwork of (1) slot canyons incised during post-glacial incision; (2) vestiges of slot canyons cut upon an earlier (middle to late Würmian?) cycle of base-level rise and fall; (3) reactivated reaches up to ~200m in width of inner bedrock gorge that are watershed at present, and more than at least ~30ka in age; and (4) abandoned, sediment-filled reaches of bedrock canyons that also must be older than 30ka and that are exposed alongside the active streams. ‘Multi-cyclic’ bedrock canyon systems composed of reaches of markedly different ages may be common in mountain ranges subject to glaciations and/or mass wasting.

Sylvicultural procedures in catchment areas of the mountain streams as exemplified by the Skrzyczne massif in Poland

Abstract Extensive disintegration of spruce forests in the Beskidy Mts. in South Poland generates a need to regenerate sizeable areas as well as to rebuild forest stands which have defended themselves against breakdown. In practice, the magnitude of relevant management tasks does not allow for keeping up with the progressive destruction of forest, especially at higher altitudes, where natural regeneration does not occur as much as necessary. In addition, the species composition is limited to spruce, sometimes accompanied by beech and fir, whereas other species have a negligible share. What may be helpful in solving this problem is the method of regeneration of such areas and of establishment of under-canopy cultures, consisting of patchwork, multi-stage regeneration task performance, starting from the areas with the best chance of reforestation success and using the existing self-sown trees. Such areas undoubtedly include habitats with better water balance, i.e. humid habitats (in the case of larger areas, distinguished in the forest management plan as humid forest site types). The aim of the present study was to propose management of watercourses and headwater areas in the region of the Skrzyczne massif where the selected catchments are situated on the southern (the Malinowski Stream) and the northern (the Roztoka Czyrna stream) slopes of this massif. The research was carried out in August 2012 and included juxtaposition of available hydrological maps with actual field conditions along with identification of springs and streams and the course of their beds in order to update the existing data. The updating of the forest numerical maps in the existing databases of the State Forests IT System (SILP) included verification of the course of streams and determination of their nature (permanent or periodic) with a division into the existing ones and the added ones. The data was recorded against the background of the division of the forest surface, contour lines, major roads, climate and plant floors and forest habitat types. The total length of streams was ascertained. The catchment areas and areas along their beds were determined by adopting variable distances from the beds, depending on climate and plant zones and the slope gradient. The adopted distances were: 5 m in the upper forest zone, 10 m in the middle forest zone, 20 m in the lower forest zone on both sides of the bed and in the headwater area within the radius of 10 m from a source. Specific sylvicultural procedures in headwater areas and in the neighbourhood of watercourses were described in each climatic and vegetation zones.

Morphological organization of a steep, tropical headwater stream: The aspect of channel bifurcation

Channel characterization and instream wood surveys demonstrate the spatial complexity of an ungauged, tropical headwater stream (HWS) in the Tilarán Mountains of Costa Rica. Throughout the stream course, we characterized 29 individual reaches based on their morphological organization and instream wood occurrences. Bifurcated reaches were the most numerous and consistently distributed. They also had the highest values of wood abundance and loading and contained the majority of unattached instream wood. We selected two bifurcated reaches for ultrahigh resolution terrestrial laser scanning (TLS) surveys. Orthographic TLS produced millimeter-resolution point cloud data sets from which 2cm, planimetric-resolution digital elevation models (DEMs) of the channel surface were derived for both reaches. Cross-sectional surveys of these DEMs, using the River Bathymetry Toolkit (RBT), produced hydraulic geometries at two flow levels (high and low) for every meter-length of channel reach. We input these geometries into a one-dimensional, analytical model to demonstrate the downstream evolution of mean stream power through varying morphology elements. Mean stream power variation displays a regular pattern through the vertical modulation of step-pool sequences, but this regular pattern is lost through channel widening and bifurcation. Reach geometric data indicates that increasing width-to-depth ratio is the most notable feature of channel bifurcation and corresponds to a reduction in slope and roughness variation. This primary understanding of channel dynamics denotes the complex organization of a tropical HWS and promotes further research into tropical HWS systems.

2D Geoelectric Imaging of the Uneme-Nekhua Fracture Zone

We have employed 2D geoelectric imaging to reveal the geometry and nature of a fracture zone in Uneme-Nekhua, southwestern Nigeria. The fracture zone is discernable from an outcropping rock scarp and appears to define the course of a seasonal stream. Data were acquired using the dipole-dipole survey array configuration with electrode separation of 6 m and a maximum dipole length of 60 m. Three traverses with lengths varying between 72 m and 120 m were laid orthogonal to the course of the seasonal stream. 2D geoelectric images of the subsurface along the profiles imaged a north-south trending fracture zone. This fracture zone appears to consist of two vertical fractures with more intense definition downstream. The eastern fracture is buried by recent sediment, while the western fracture appears to have experienced more recent tectonic activity as it appears to penetrate through the near surface. Perhaps at some point, deformation ceased on the eastern fracture and further strain was transferred to the western fracture. The fracture zone generally defines the course of the north-south seasonal stream with the exception of the downstream end where the fracture appears to have died out entirely. Two associated basement trenches lying parallel to and east of the fracture zone are also imaged.

Meandering of Tributaries of the Tigris River Due to Mass Movements within Iraq

Tigris and Euphrates are the main rivers in Iraq. The former has 5 main tributaries while the latter has no tributaries within Iraq. All these rivers exhibit meandering and/or shifting of their courses due to many reasons; such as mass movements and alluvial fan's development. The meandering and shifting of river courses due to mass movements is dealt with in this study. Many examples are given from different parts of Iraq within different rivers and streams. In each case, the geology of the involved area is described; the reasons of the shifting and/or meandering of the river course are given. GIS technique was used to determine the coverage of the involved area. Landsat, Google Earth and DEM images were used to indicate the suffered areas from shifting and meandering of the rivers and streams. When possible, age of the shifting and/or meandering of the river and stream courses was estimated; using exposure age determination; mainly depending on the presence of river terraces, erosional forms, vegetation cover and the maturity of the involved area. Some of the given examples of shifting of river courses were found to be still active; others are inactive. In many cases, indications for very large mass movement phenomena were seen. Moreover, some of the large involved areas are highly populated, others includes few houses and/ or farms. The majority of the meanders are developed due to mass movement phenomena; others are caused by alluvial fans and/or tectonic features, lime plunging of anticlines.

Classification of freshwater ice conditions on the Alaskan Arctic Coastal Plain using ground penetrating radar and TerraSAR-X satellite data

Arctic freshwater ecosystems have responded rapidly to climatic changes over the last half century. Lakes and rivers are experiencing a thinning of the seasonal ice cover, which may increase potential over-wintering freshwater habitat, winter water supply for industrial withdrawal, and permafrost degradation. Here, we combined the use of ground penetrating radar (GPR) and high-resolution (HR) spotlight TerraSAR-X (TSX) satellite data (1.25 m resolution) to identify and characterize floating ice and grounded ice conditions in lakes, ponds, beaded stream pools, and an alluvial river channel. Classified ice conditions from the GPR and the TSX data showed excellent agreement: 90.6% for a predominantly floating ice lake, 99.7% for a grounded ice lake, 79.0% for a beaded stream course, and 92.1% for the alluvial river channel. A GIS-based analysis of 890 surface water features larger than 0.01 ha showed that 42% of the total surface water area potentially provided over-wintering habitat during the 2012/2013 winter. Lakes accounted for 89% of this area, whereas the alluvial river channel accounted for 10% and ponds and beaded stream pools each accounted for <1%. Identification of smaller landscape features such as beaded stream pools may be important because of their distribution and role in connecting other water bodies on the landscape. These findings advance techniques for detecting and knowledge associated with potential winter habitat distribution for fish and invertebrates at the local scale in a region of the Arctic with increasing stressors related to climate and land use change.

Variation in morphological characteristics of Japanese fluvial sculpin related to different environmental conditions in a single river system in eastern Japan

AbstractStream fish with low mobility are often restricted to a narrow range of a stream course, and their morphological characters tend to be affected substantially by the environmental conditions of their habitat. We examined the relationships between environmental conditions and morphological characters of Japanese fluvial sculpin (Cottus pollux), a small, benthic fish with low mobility, at seven tributaries of the same river system in eastern Japan. Discriminant function analysis (DFA) indicated significant morphological differences in sculpins amongst the seven tributaries, and over 80% of individuals were classified correctly in each tributary. The strong positive correlation/loadings on the first discriminant function (DF1: 49.9% of total variation) were anterior caudal peduncle depth (0.436) and caudal peduncle truss (0.387), both of which could be regarded as an attribute of caudal peduncle depth. The second discriminant function (DF2: 16.5% of total variation) had a high negative loading for distance between the posterior first dorsal fin and anterior anal fin (−0.454), which could be regarded as an attribute of body depth. Correlation analysis indicated that sculpin tended to have a lower caudal peduncle depth under faster bottom current velocities at the tributary scale. Individuals deviating substantially from the centroid of DF2 in each tributary had a poorer body condition. Our results suggest the possibility of changes in the morphological characters of Japanese fluvial sculpin in relation to environmental conditions even at the tributary scale within the same river system.

Nasal douches for diseases of the nose and the paranasal sinuses—a comparative in vitro investigation

Nasal douches are applied in great number of diseases of the nose and the paranasal sinuses. For this purpose, many different kinds of nasal douching systems have been introduced into the market. The aim of this study was to examine the irrigation characteristics of the current nasal douching systems. In this context, 26 nasal douching systems were compared regarding irrigation volume, irrigation duration, flow rate and pressure and course of the irrigation stream. The following procedure was applied: First, the spontaneous flow through the nasal douche was measured, then the flow under compression. Finally, these procedures were repeated using a nose model. Furthermore, we asked the manufacturers for information concerning possible cleaning and disinfection techniques. Douching period and flow rate highly depend on physical parameters: distance between liquid column and outlet (hydrostatic pressure) and form and size of the outlet (energy loss because of friction/turbulence). A weak irrigation stream was found in spontaneous release of the douching system when both douching pressure and flow rate offered low values. The douching of the nose model showed that the incompressible nasal douches only reached the lower nasal passage. Only the compressible nasal douching systems led to a diffuse moisturization as well as to a perfusion of the entire nasal cavity. Systematic evaluation of the different recommended cleaning and disinfection methods of the nasal douching systems is still missing. Nasal douches are often recommended in many diseases of the nose and the paranasal sinuses. In this comparative in vitro study, physical parameters and material properties of the nasal douching systems were examined for the first time. For irrigation of the whole nasal cavity and paranasal sinuses, compressible douching systems are recommended which have a minimum output pressure of 120mbar, a good connection of the outlet to the nostril with a possible insertion into the nasal vestibule and an irrigation stream which is directed upwards (45°). The material should be transparent, easy to clean and disinfect and should not contain harmful elements.

Delineation of fluvial sediment architecture of subalpine riverine systems using noninvasive hydrogeophysical methods

River management and restoration measures are of increasing importance for integrated water resources management (IWRM) as well as for ecosystem services. However, often river management mainly considers engineering and construction aspects only and the hydrogeological settings as the properties and functions of ancient fluvial systems are neglected which often do not lead to the desired outcome. Knowledge of the distribution of sediment units could contribute to a more efficient restoration. In this study, we present two noninvasive approaches for delineation of fluvial sediment architecture that can form a basis for the restoration, particularly in areas where site disturbance is not permitted. We investigate the floodplain of a heavily modified low-mountain river in Switzerland using different hydrogeophysical methods. In the first approach, we use data from electromagnetic induction (EMI) with four different integral depths (0.75–6 m) and gamma-spectrometry as well as the elevation data as input for a K-means cluster algorithm. The generated cluster map of the surface combines the main characteristics from multilayered input data and delineates areas of varying soil properties. The resulting map provides an indication of areas with different sedimentary units. In the second approach, we develop a new iterative method for the generation of a geological structure model (GSM) by means of various EMI forward models. We vary the geological input parameters based on the measured data until the predicted EMI maps match the measured EMI values. Subsequently, we use the best matched input data for the GSM generation. The derived GSM provides a 3D delineation of possible ancient stream courses. A comparison with an independent ground penetrating radar (GPR) profile confirmed the delineations on the cluster map as well as the vertical changes of the GSM qualitatively. Thus, each of the approaches had the capacity for detecting sedimentary units with distinct hydraulic properties as an indication of former stream courses. The developed methodology presents a promising tool for the characterization of test sites with no additional subsurface information.

Variation in life-history traits of male Japanese fluvial sculpin Cottus pollux in relation to nest abundance along a stream course

Life-history theory predicts the occurrence of variation in the life-history traits of fish populations under different environmental conditions; however, most studies have focused on such variation between geographically separated populations. We compared breeding characteristics and life-history traits of the Japanese fluvial sculpin (Cottus pollux), a bottom-dwelling nest-holding fish, between two adjacent sites sub-divided by a weir along a stream course in central Japan. Males in the area with a lower abundance of nest sites reached sexual maturity at an earlier age and had a shorter life span than males in the area with sufficient nest abundance. Size-dependent male reproduction was found only in areas with a shortage of nest sites, supporting the assumption of competitive exclusion among males for nests. Females matured at the same age in both sites with no differences in age-specific growth rates and mortality. Our results provide evidence for life-history variation in age and size at maturity and age-specific mortality schedule of males in nest-holding fishes in a single stream population via different sexual selection regimes related to differences in nest abundance between sites.