DISTRIBUTION OF PRESENT FORAMINIFERA IN A MEDITERRANEAN ECOSYSTEM - PREVOST LAGUNA

The present study aims to determine the organization of Foraminifera i n a Mediterranean paralic ecosystem, the Prevost laguna, and to put in obviousness their distribution in function of the confinement zones. The distribution of Foraminifera is studied thanks to different method s of population study (specific richness, density, Fisher diversity in dex, correspondence analysis). The distribution of characteristic spec ies is analyzed from the distribution of absolute and relative abundan ce. We observe, like in all paralic ecosystems studied up to now, a de crease of specific richness, from the areas under marine influence to the marginal lagoonal reaches. However, the density distribution is no t established according to this same gradient. The strong densities no ticed in more confined zones should be related to the chlorophycea alg a proliferation that characterizes this laguna. Populations of Foramin ifera are weakly diversified and characterize perfectly this ecosystem that is situated essentially in zone IV-V of confinement.