Estudo da distribuição da meiofauna em um gradiente salino no estuário de Pirangi-RN: com ênfase no grupo Tardigrada (Filo Tardigrada).

Abstract

The meiofauna consists of an ecological group composed of microscopic metazoans, living in small interstitial spaces among the sand grains with representatives in aquatic ecosystems (marine, estuarine and freshwater) and in moist soil, water-sediment interface. These reduced body size of organisms, ranging from 0.05 mm to 0.045mm in length make an important role in nutrient cycling and energy flow from the lower levels to the higher marine and estuarine trophic web.These animals possess the morphology, physiology and life cycle characteristics, and is also found in association with other creatures, like as algae. Through this work we studied the influence of salinity in the structure and composition of meiofauna and tardigradofauna of Pirangi estuary - RN, and held the first records Batillipes pennaki and Batillipes sp. nov. to the Rio Grande do Norte. The sampling occurred in April 2014, along the estuary in three transects on the north bank and three transects on the south bank with four replicates each, totaling 24 samples. These points for prospecting were determined according to the salinity gradient. Samples were collected at a depth of 10cm, with the aid of a PVC tube with 9.42cm² inner area. The meiofauna of this ecosystem was composed by: Nematoda, Tardigrada, Oligochaeta, Gastrotricha, Turbellaria, Copepoda, Acari, Ostracoda and Polychaeta. The meiofauna community of the north and south margins of the estuary presented correlations with organic matter and salinity, and the north margin is different significantly in their structure and meiofauna composition between sampling point sand the south margin (significance level of 0.1%). The Tardigrada fauna was somewhat different, with two species Batillipes pennaki e Batillipes sp. nov. being dominated by B. pennaki. The new specie of Tardigrada B. sp. nov. description is in process. These unprecedented record for the Rio Grande do Norte emphasizing Phylum Tardigrada, demonstrate the importance of new taxonomic studies about this group meiofaunistico.