Composição e distribuição espacial de foraminíferos bentônicos de dois estuários tropicais (7°S, Paraíba, Brasil)

Abstract

Estuaries are transitional environments characterized by strong environmental gradients and, due to their proximity to the ocean, these environments are ideal for various human activities, which increases the range of stressors. The foraminifera are unicellular eukaryotes, which are considered good bioindicators. The present study analyzed the composition and distribution of benthic foraminifera from two estuaries of Paraíba. Abiotic data such as salinity, temperature, pH, dissolved oxygen, dissolved solids and particle size were also collected. Were observed fifty species in the Mamanguape river estuary and 60 species in the Paraíba river estuary, with a predominance of calcareous species, followed by miliolid and agglutinant species. Was observed a limited variation of salinity and this probably reflect in the dominance of calcareous species of both estuaries. The species that contributed mostly to the structuring of the community in the Mamanguape River estuary were Ammonia parkinsoniana, Cribroelphidium excavatum, Ammonia tepida and Haynesina germanica, which are typical species of estuarine environments, supporting the range of salinity. Amongst the species that mostly contributed to the Paraíba River estuary group there were both typical estuarine and marine species, such as A. tepida, A. parkinsoniana and C. excavatum, and A. gibbosa, E. repandus and Q. lamarckiana, respectively. Ammonia tepida is a species tolerant to stress and environmental pollution, and a greater abundance of this species was observed in the Paraíba river estuary, which may indicate that this estuary is more impacted than the Mamanguape river estuary, where a greater abundance of A. parkinsoniana was observed, a typical species from pristine environments.