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Advisor(s)
Abstract(s)
This study analyses the taxonomy, ecology and biogeography of the species of
benthic foraminifera living on the intertidal margins of the Guadiana Estuary (SE Portugal, SW Spain). Of the 54 taxa identified during sampling campaigns in winter and
summer, 49 are systematically listed and illustrated by scanning electron microscope
(SEM) photographs. Ammonia spp. were the most ubiquitous calcareous taxa in both
seasons. Morphological analysis and SEM images suggested three distinct morphotypes of the genus Ammonia, two of which proved to be Ammonia aberdoveyensis on
the basis of partial rRNA analyses. Jadammina macrescens and Miliammina fusca
were the most ubiquitous agglutinated taxa in the estuary. Jadammina macrescens
dominates the upper-marsh zones almost exclusively, occurring at very high densities.
Ammonia spp. are the most abundant in the low-marsh and tidal-flats of the lower
reaches of the Guadiana Estuary, but are widespread throughout the estuary, especially during summer when environmental conditions favor their proliferation. Miliammina fusca dominates the sparsely vegetated low-marsh and tidal-flat zones of the
upper reaches, where it is associated with calcareous species. Due to its geographical
position, the Guadiana system shares characteristics of both Atlantic and Mediterranean estuaries. This is reflected in the foraminiferal assemblages, with a dominance of
thermophilous species and an ecological zonation typical of the Mediterranean climatic
zone.
Description
Keywords
Benthic foraminifera Taxonomy Biogeography Ecological zonation Genetic analysis Guadiana Estuary
Citation
Publisher
Coquina Press