Distribuição espaço-temporal da meiofauna em uma praia arenosa tropical.

Abstract

Sandy beaches have a high biodiversity and protect one of the most extent environments throughout the Brazilian coast. Presenting a fauna of invertebrates that are resistant and adapt to various changes. Meiofauna is projected by invertebrate metazoan organisms that measure 0.044 mm and 0.5 mm. The research aims to characterize the space-time structure of the medium-phained community based on composition and abundance. The collections were performed on Cup beach during the sea bass and two perpendicular transects were chosen to the waterline and equidistant in 100 meters. In each transect, four average collection points were defined in three portions (upper, middle and lower) and one in shallow infralitoral. In each of these points three replicated medium and additional replicated replicated were collected for analysis of particle size factors, using a 9.6 cm2 internal PVC cylindrical witness. As a sample of the biological material were added to 4% - prepared saline plastic pots. Meiofauna samples were washed through the overlapping geological sieves set, with 500 μm and 45 um laboratory mesh intervals and treches on Dolfuss plates under stereomicroscope for screening and identification of the middle -phanainistic organisms present. The half -black was composed of 11 taxa being: Nematoda, Copepoda, Polychaeta, Oligochaeta, Acoela, Acari, Gastrotricha, Ostracoda, Nemertea, Tardigrated and Amphipoda. The Nematoda group was the most abundant in both months. The total density of months,being higher, varied between the months (July and August) and lower in the dry period (September and November). Among the areas, average and infralittoral medium litoral stand out for the highest densities of organisms. Permanova's result also confirmed the significant differences in the meiofauna community between the months, transects and zones of the nMDS figures viewer. Among the abiotic variables, they confirm the average grain size that stands out having an influence of 68% of the meiofauna community.