The benthic foraminiferal communities of northern Adriatic continental shelf

Off the Po Delta in the northern Adriatic, three different foraminiferal associations were identified in the fraction > 0.125 mm of 25 sediment samples. The first association concerns sample stations between depths of 5 and 13.5 m in the shallow, nutrient rich belt and is characterized by dominant Ammonia beccarii. The second occupies the 29.5-38.5 m deep, nutrient rich zone of clay-rich sediment, where inputs from the Po are concentrated, and is dominated by Nonionella opima. The third association, in the 21-46-m-deep and nutrient poor zone, is dominated by Textularia agglutinans. The same distribution of communities was obtained using total association (living and dead specimens) and biocenosis (stained individuals). The good correspondence with the foraminiferal distribution described in the past indicates that, in spite of the occurrence of anoxic and dysoxic events, the environmental state in the northern Adriatic may be considered stable.