The effects of regional (hydrogeology and geomorphology) and local (sediment and hydrology) characteristics on hyporheic assemblages were studied along a 40-km reach of a large gravel-bed river. Hyporheic water and fauna were sampled at the upstream and downstream positions of 15 large gravel bars. The resulting 30 stations varied in their sediment grain size, stability and direction of river-aquifer exchanges.
View Article and Find Full Text PDFIntensive sampling performed in the area of Oum El Bouaghi (Northeastern Algeria) yielded a new species of the stygobiont amphipod Pseudoniphargus, P. djemoi, in wells located in the plain of Tamlouka. The new species belongs to a group that shares the display of a uropod 3 exopod extremely elongate and upcurved in the male, whereas its peduncle is only moderately elongate.
View Article and Find Full Text PDFWater exchanges through the hyporheic zone are crucial to many ecological processes in streams. One major challenge for river managers is to find a practical method for localizing these exchanges using rapid data acquisition techniques. This work compares spatially continuous data, acquired by Thermal Infrared (TIR) techniques, with discrete data collected in surface water and in the hyporheic zone (DHM), at sites of expected water exchanges (gravel bars).
View Article and Find Full Text PDFEcological criteria are needed for a comprehensive evaluation of groundwater ecosystem health by including biological components with the physical and chemical properties that are already required by European directives. Two methodological approaches to assess the ecological status of groundwater ecosystems were combined in two alluvial plains (the Ariège and Hers Rivers, southwestern France) varying in agriculture intensity (from grassland to crop rotation including maize and sunflower, and to maize monoculture). In the first approach, the composition of invertebrate assemblages (only obligate-groundwater crustaceans, i.
View Article and Find Full Text PDFThe hyporheic zone of river ecosystems provides a habitat for a diverse macroinvertebrate community that makes a vital contribution to ecosystem functioning and biodiversity. However, effective methods for sampling this community have proved difficult to establish, due to the inaccessibility of subsurface sediments. The aim of this study was to compare the two most common semi-quantitative macroinvertebrate pump-sampling techniques: Bou-Rouch and vacuum-pump sampling.
View Article and Find Full Text PDFLepidocharontidae Galassi & Bruce, fam. n. is erected, containing Lepidocharon Galassi & Bruce, gen.
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