Biodiversidade e distribuição da nematofauna em um gradiente salino no estuário de Pirangi - RN.

Abstract

Estuaries are ecosystems that impose severe abiotic conditions leading to the biota of the meiofauna to undergo unique morphotisiological adaptations. The Nematoda taxon is an example of group that adapts very well to these conditions, as it presents several strategies for survival and great adaptive success in these environments. The study of biodiversity and distribution of the nematofaunistic community through a saline gradient was carried out in the Pirangi Estuary, located on the coast of Rio Grande do Norte. The organisms were analyzed through the samples collected in September 2014 throughout the estuary in three transects on the south bank and three transects on the north bank, with four replicates each, totaling 24 samples. The prospecting points were chosen through the salinity gradient. The meiofauna was composed of 9 large groups, and the community nematofaunistic was represented by 31 genera. The largest number of genres was found in the highest salinity concentration, highlighting the relationship of this group with the salinity. The structure of the nematofaunistic community was related to the variables: sal linity, temperature, sediment granulometry and organic matter content. Nematoda was the dominant taxonomic group at all salinity points. The results suggest that the salinity, particle size and organic matter variables were the main factors associated with the spatial distribution of the structure of the nematofaunistic community. Statistically the meiofaunistic community and the nematofaunistic community, from the margin south were different from the north bank, as the low concentration points of salinity were different from high salinity concentration points. The present work brings relevant data for the Brazilian estuarine nematofauna.