Regulation causes nitrogen cycling discontinuities in Mediterranean rivers.

River regulation has fundamentally altered large sections of the world's river networks. The effects of dams on the structural properties of downstream reaches are well documented, but less is known about their effect on river ecosystem processes. We investigated the effect of dams on river nutrient cycling by comparing net uptake of total dissolved nitrogen (TDN), phosphorus (TDP) and organic carbon (DOC) in river reaches located upstream and downstream from three reservoir systems in the Ebro River basin (NE Iberian Peninsula).

Pollution-induced community tolerance to non-steroidal anti-inflammatory drugs (NSAIDs) in fluvial biofilm communities affected by WWTP effluents.

We assessed the tolerance acquired by stream biofilms to two non-steroidal anti-inflammatory-drugs (NSAIDs), ibuprofen and diclofenac. Biofilms came from a stream system receiving the effluent of a wastewater treatment plant (WWTP). The response of biofilms from a non-polluted site (upstream the WWTP) was compared to that of others downstream with relevant and decreasing levels of NSAIDs.