| Summary: | This collection contains genetic extracts from soil microbes collected during periodic soil sampling at NEON terrestrial sites (NEON sample class: mic_dnaExtraction_in.soilDnaSampleID). Three unique locations are sampled per plot with ten soil plots per site. Bouts occur three times per year in order to capture the prevailing conditions at the site during different seasons, except in Alaska where there only 1 bout is possible. However, the frequency of genetic analysis and thus DNA archiving varies by site type. Soil sampling is conducted to a maximum depth of 30 ± 1 cm, and when organic (O) and mineral (M) horizons are present within a single profile, they are separated prior to analysis and archiving. However, other sub-horizons are not separated. During the majority of bouts, only the top horizon (O if present, else M) is analyzed for genetic content. Soils are homogenized and non-soil material is removed by hand in the field, then subsamples are immediately frozen on dry ice. They are maintained in ultra-low temperature freezers until they are shipped to an analytical facility for DNA extraction, sample preparation and sequencing. During peak greenness bouts, subsamples from each of the 3 sampling locations per plot are combined to form a plot-level composite that is used for metagenomics analysis. Laboratory metadata are delivered to NEON for QC testing and acceptance, and then formatted for upload to public sequence repositories. Genetic extracts are shipped from the analytical facility in 96-well plates to the NEON Biorepository to be archived at -80 degrees Celsius. See links below for NEON data products that provide physical, chemical, and biological measurements for these same soils (soil pH, moisture, and microbial properties are always measured; chemical properties are determined only for a subset of collection bouts). The metabarcoding protocol used by Battelle Applied Genomics is available in the NEON document library (https://data.neonscience.org/documents).
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