BACKGROUND This study investigates the relationship between salinity and biotic communities (primary producers and macroinvertebrates) in Rambla Salada, a Mediterranean hypersaline stream in SE Spain. Since the 1980's, the mean salinity of the stream has fallen from about 100 g L(-1) to 35.5 g L(-1), due to intensive irrigated agriculture in the watershed. Furthermore, large dilutions occur occ...

Microscopical and molecular analyses were used to investigate the diversity and spatial community structure of spring phytoplankton all along the estuarine gradient in a macrotidal ecosystem, the Baie des Veys (eastern English Channel). Taxa distribution at high tide in the water column appeared to be mainly driven by the tidal force which superimposed on the natural salinity gradient, resultin...

Spatial and temporal variations of reproduction variables the two cyclopoid copepods Oithona nana Giesbrecht, 1893 similis Claus, 1866 were evaluated monthly from September 2007 to August 2008 in four ponds at different salinities solar saltern Sfax, Tunisia, under hypersaline conditions. Along salinity gradient abundance O. declined 14,900 ± 15,200 ind. m-3 (A1) 6,800 7,200 (C31) 13,800 17,100...

Where sexual and asexual forms coexist within a species, the asexuals are often found to be prevalent in marginal habitats. This asexual distribution pattern has received evolutionary attention linked to the paradox of sex. In many marine species, there is a distributional trend of asexual modes being more common in lower salinity waters regarded as the ecogeographic marginal, being explained b...