Effects on Mediterranean lagoon macrobenthos of a river diversion: assessment and analytical review.

Abstract

Continuous input of freshwater in the Etang de Berre for nearly 20 yr, due to the diversion of the Durance river has completely modified the biological balance of the lagoon. Pollution control measures involve a 90% reduction of the pollution inflow into the lagoon. The last 1983 survey undertaken does not show any particular effects of these measures on the macrobenthos, which is limited to a narrow coastal zone. The bottom of the lagoon is azoic at depth >5 m. Analysis demonstrates the major influence of erratic freshwater inputs on degradation of the benthic ecosystem, by their effects on salinity variations, silt input and the impoverishment of dissolved oxygen.-from Authors