Influence of the environmental characteristics of mangrove forests on recent benthic foraminifera in the Gulf of Uraba, Colombian Caribbean

Mangrove forests with different characteristics have developed in the Gulf of Uraba (Colombia). Eighty-two sediment samples were studied for species of foraminifera and their environmental dependence. Ten agglutinated species and one calcareous species dominated in these mangroves. Foraminifera were absent in mangrove areas exposed to high hydraulic energy (waves) or high human affectation. Two characteristic assemblages were found. The first one, represented by Milliammina fusca, the most dominant species, was related to finer substrates and lower salinities. The second one, represented by Ammonia beccarii, the most common calcareous species, was found in polluted low-oxygen environments. Haplophragmoides canariensis and Trochammina squamata, small species, showed a preference for places with abundant organic matter. A conceptual model is proposed that relates the benthic foraminifera to the hydrodynamics, grain size, organic matter content, and pollution.