Situación medioambiental de la marisma Joyel (Cantabria): datos aportados por los foraminíferos bentónicos

Abstract

A total of sixty nine species of benthic foraminifers have been identified in the Joyel-Ria of Quejo marsh (Cantabria, N Spain). Fifty six of those species had living individuals in the time of sampling. Main foraminifer assemblages change from the mouth to the head of the estuary. Thus, in the silty channels of the marsh area, the most abundant species is Ammonia tepida, while in the vegetated middle marsh area is Trochammina inflata the dominant species. In the mid area of the Ria of Quejo, dominant assemblage is composed by Ammonia tepida, Cribroelphidium williamsoni, Haynesina germanica and Lobatula lobatula. The last one, besides Rosalina globularis are dominant at the mouth and with Quinqueloculina seminula, in the beaches. The occurrence of abundant living individuals of A. tepida at the flooded area of the head, now occupied by an old sewage point, confirms the recovering of this area thanks to the environmental policy of the last years. Finally, the occurrence of live specimens of Ammonia tepida and Haynesina germanica inside the lagoon of Joyel indicates the influence of brackish water