In humid regions, where gaining river conditions generally prevail, daily hydroelectric dam releases alter downstream surface water–groundwater interactions by reversing the head gradient between river and adjacent groundwater. Previously, it has been noted that artificial stage changes due to dam releases enhance hyporheic exchange. Here we investigate the regulated Deerfield River in northwes...

Relationships among the historically isolated lineages of Pseudobarbus were reconstructed using molecular and morphological data. Contradictions between the molecular and morphological phylogenies suggest convergent evolution and homoplasy in some morphological characters. The earliest divergence in Pseudobarbus was between P. quathlambae in Lesotho and the rest of the genus associated with the...

The effects of five towns on river water pollution were examined along the Łyna River (southern watershed of the Baltic Sea, northern Poland). The relationships among the spatially derived indicators of urbanization, environmental variables, and physico-chemical and microbiological data (heterotrophic plate count at 22 and 37 °C, and fecal coli) obtained from longitudinal river profiling have b...

fish species diversity, distribution and abundance were studied in the sardabrud and chalus rivers, in the southern caspian sea basin, during 1992 and 1993 in five and four stations respectively, by monthly collections using electrofishing device. in total, 3200 fish specimens, including 15 species in sardabrud river and 12 species in chalus river, were investigated. the fish comprised of 13 ge...

the present study reports range extansion of moenkhausia oligolepis to the pindaré river drainage, of the mearim river basin, and itapecuru river basin, maranhão state, northeastern brazil. this species was previously known only from venezuela, guianas, and the amazon river basins. in addition, we present some meristic and morphometric data of the specimens herein examined and discuss on its di...

A total of 14 perfluorinated compounds (PFCs) were quantified in river water samples collected from tributaries of the Pearl River (Guangzhou Province, south China) and the Yangtze River (central China). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the two compounds with the highest concentrations. PFOS concentrations ranged from 0.90 to 99 ng...

  Mahisefid is the most popular fish in Iran with the highest economic value. The analysis of mitochondrial DNA has been extensively used as a marker for population genetic studies and is a powerful tool in studies of gene flow and evolutionary biology. Two hundred ninety four samples were collected from Sefid Rud River (100), Lamir River (98), Shir Rud River (48) and Tajan River (48) during s...

Fresh Water Rivers are one of the most important aquatic ecosystems in arid and semi-arid regions of Iran in point of biodiversity and drinking water views. Damghanroud River is one of these rivers at Semnan province that during past years has been threatened by drought and anthropogenic pollutions. This river supplies some parts of drinking water of Damghan city and some vicinity villages. The...