Distribución de los Foraminíferos bentónicos recientes en el estuario de T ina Menor (Cantabria)

Resumen

With the aim to describe the recent distribution of the benthic foraminifers, 17 samples from sediments of the Tina Menor estuary (Cantabria, N Spain) have been analysed. A total of 50 species have been identified 30 of which bearing numerous living individuals in the time of sampling; this biocenoses reaches the 43.5% of the total picked specimens. Lobatula lobatula and Rosalina globularis form the main assemblage in the outer estuary with marine influence. Miliammina fusca dominates the mud flats and marshes of the mid estuary. Ammonia tepida, Cribroelphidium williamsoni and Haynesina germanica generally live in the euryhaline upper estuary. The elevated percentage of Miliammina fusca characterizes Tina Menor in relation with other estuaries from Cantabria. The high amount of sand, even in the mud flats with or without vegetation, could be the responsible of this elevated percentage. The occurrence of euryhaline benthic foraminifer species in sandy-silty sediments of the mid estuary, far from their natural habitat, evidences fresh water surgences located in the contact between Quaternary materials from the estuary and quartzites and limestones of the Paleozoic.