SRP172878 PRJNA508881 Microbial diversity of Totoras periphyton from Titikaka lake Dissolved As in lake Titicaca is close to the WHO limit for drinking water. We investigate As cycling in water, sediment, totora plants (Schoenoplectus californicus) and periphyton growing on the stems, As speciation and localization in periphyton, and As speciation in water. We described highly variable As accumulation in periphyton. We determine microbial diversity of As hyperaccumulator and not acccumulator periphytons.