Diversity of planktonic and benthic communities in the high‐altitude Salar de Pedernales basin, Atacama Desert, Chile

Resumo

Salar de Pedernales basin is located at 3,300 meters above sea level in the Atacama Desert, Chile, covering an area of 3,000 km². This ecosystem is characterized by high exposure to ultraviolet radiation, low humidity, huge variations in ions content and extreme thermal gradients. Despite these extreme conditions, it has a rich autochthonous fauna and flora. Aquatic biodiversity in the basin is still poorly documented. Our study assessed compositional changes of planktonic and benthic communities across several salt flats (Pedernales S-O, Piedra Parada, La Laguna), natural water courses (wetland and creeks), an artificial stream and lagoon (Pedernales N-E), and their relationship with local physicochemical parameters. Our results show that the Salar de Pedernales basin is a highly heterogeneous ecosystem principally influenced by conductivity, pH, and major ions. Community diversity was high at all locations except for the artificial stream. Microalgae were spatially similar with major changes observed in the disturbed habitats. The composition of the invertebrate communities strongly varied among locations but displayed distinct composition in the perturbed locations (Salar de Pedernales N-E). Distance-based redundancy analysis revealed that phytoplankton and -benthos were driven by changes in trace metals and nitrate, whereas zooplankton communities were mainly related to osmotic stress. Our data highlight the remarkable biodiversity of the natural water bodies of the Salar de Pedernales basin and point to the potential effects of anthropogenic intervention on the biota in these extreme habitats.