The National Ecological Observatory Network (NEON) is research platform designed to assess the effects of ecological change on ecosystems across North America. NEON’s aquatic program includes of a suite of instrument and observational data collected at 34 sites: 24 wadeable streams, 7 lakes, and 3 large rivers ranging from Puerto Rico to Alaska. Benthic macroinvertebrate samples are collected at all sites, and zooplankton samples are collected at lake sites, three times per year (spring, summer, fall).
Morphological taxonomy is a traditional method of assessing invertebrate communities in aquatic habitats. High-throughput DNA sequencing methods, or metabarcoding, are becoming more common as quicker, potentially less expensive, ways to assess aquatic communities. Samples are collected at NEON aquatic sites using quantitative methods for morphological taxonomic analysis, while a second set of samples are collected at the same time and location for metabarcode analysis. Samples are preserved in the field and sent to external facilities for analysis. Morphological taxonomy samples are processed and identified to the lowest practical taxonomic level. Metabarcode samples are homogenized prior to DNA extraction, and two fragments of the COI gene are PCR-amplified and Illumina sequenced. NEON morphological taxonomy data are publicly available and hosted on the NEON data portal, while sequence data are hosted on MG-RAST. DNA extracts are stored at the NEON bioarchive facility for further use by the community.
Results/Conclusions
A pilot study of NEON macroinvertebrate and zooplankton samples from 3 sites, 1 stream in Virginia and 2 lakes in Florida, show that there is good correlation between taxon lists obtained from metabarcode bioinformatics and morphological taxonomy at the family level. Sequence data in the pilot study were categorized by taxon using MG-RAST’s Subsystems database, which showed potential sources of contamination (e.g., primate sequences) as well as taxa that may be poorly represented by the sequences in the Subsystems database. As more data become available, we hope to resolve some of these mismatches between the MG-RAST database and NEON sequence data.
Macroinvertebrate and zooplankton sequence data from the full suite of NEON aquatic sites will be available in 2019. Aquatic metabarcode data are becoming a more common method of bioassessment. Data from the DNA sequence and morphological taxonomy analyses are quality checked and provided freely to the public. These data, along with the DNA extracts stored at the archive facility, NEON is providing a robust resource for the scientific community.