SAMPLES ARE CURRENTLY UNAVAILABLE. Please contact the NEON Biorepository for information about when these samples will become available. Subsample for algae taxonomy (freeze-dried; NEON sample class: ptx_taxonomy_in.freezeDried). Benthic and water column field samples are collected in wadeable streams, rivers, and lakes, three times per year during the growing season using the type of sampler most suitable to the habitat and substratum types present at the site. Samples within this collection are preserved by freeze-drying. Samples are archived in 20 mL glass scintillation vials and stored at room temperature. See AOS Protocol and Procedure: Periphyton and Phytoplankton Sampling and NEON Aquatic Sampling Strategy (https://data.neonscience.org/documents) for more information about this sample class. NEON datasets (https://data.neonscience.org/home) associated with this sample class include Periphyton, Seston, and Phytoplankton Chemical Properties (chlorophyll, pheophytin, carbon, nitrogen, phosphorus, and carbon, nitrogen, and sulfur isotopes) and Periphyton, Seston, and Phytoplankton Collection.