DISTRIBUIÇÃO ESPAÇO-TEMPORAL DA COMUNIDADE FITOPLANCTÔNICA E VARIÁVEIS HIDROLÓGICAS EM UMA SALINA ARTESANAL DO ESTADO DO RIO GRANDE DO NORTE, BRASIL

Resumo

Spatial and temporal distribution of the phytoplankton community and hydrological variables in an artisanal saltworks in the State of Rio Grande do Norte, Brazil. The phytoplankton community structure was characterized by low taxon richness and biomass, and by a reduction of the specific diversity due to the selectivity of the hypersaline environmental system. The differing communities of the evaporators were characterized by a gradual reduction of the specific diversity along the water bodies course in the saltworks. Aphanothece halophytica, for its density and frequency, was responsible for both spatial and temporal distribution patterns of the community. Its dominance and distribution was rather due to the hydrodynamic management of the saltworks than to the seasonality of climatic factors itself. The salinity presented a pattern of progressive increase as the water moves along the evaporators, but without showing significant oscillations between the dry and rainy seasons. The low concentrations of nitrate and orthophosphate, and the significant negative correlations obtained from the regression of values of algal density and diversity on values of salt concentrations, evidenced the salinity as the main regulative source of the ecological processes in those hypersaline environments.

Keywords: Phytoplankton, hydrological variables, salinity, Aphanothece halophytica, saltworks, northeastern Brazil.

Descritores: Fitoplâncton, variáveis hidrológicas, salinidade, Aphanothece halophytica, salina, nordeste do Brasil.