Phytoperiphyton associated with lagoons generated by mining, San Juan river basin, Chocó-Colombia

Mining activity generates transformations in aquatic ecosystems and adjacent areas, as well as the creation of land depressions or "lagoons" that act as water reservoirs where aquatic communities develop, including the phytoperiphyton. Considering the role of this community in these environments, the purpose of this research was to study the phytoperiphytic community present in lagoons generated by mining processes, in the San Juan basin, Chocó (Colombia). Lagoons with different formation times were selected: 1-5 years, 5-10 years and 10-15 years; three lagoons for each time period. Physical and chemical variables were measured, and phytoperiphyton was collected, using an 8cm2 quadrant, obtaining a scraping area of 120cm2. The community was composed of six divisions, nine classes, 16 orders, 24 families and 33 genera, for a total density of 13108 org/cm2. The lagoons of 10-15 years presented the highest density, with Bacillariophytes as the most representative in all the studied lagoons, both in density and richness. There were differences in density between lagoons, but not in specific richness and diversity. Similarity values indicate that the lagoons have little variability in their phytoperiphytic communities. Conductivity and dissolved total solids are the variables with the greatest variation throughout the study; there are significant differences between lagoons for the variables dissolved oxygen, pH and alkalinity (p<0.05). This study constitutes a baseline for understanding the ecological dynamics of lentic environments generated by mining processes and on the development of phytoperiphytic communities in them.