Systematic review of marine environmental DNA metabarcoding studies: Toward best practices for data usability and accessibility

The emerging field of environmental DNA (eDNA) research lacks universal
guidelines for ensuring data produced are FAIR–findable, accessible,
interoperable, and reusable–despite growing awareness of the importance of
such practices. In order to better understand these data usability
challenges, we systematically reviewed 60 peer-reviewed articles
conducting a specific subset of eDNA research: metabarcoding studies in
marine environments. For each article, we characterized approximately 90
features across several categories: general article attributes and topics,
methodological choices, types of metadata included, and availability and
storage of sequence data. Analyzing these characteristics, we identified
several barriers to data accessibility, including a lack of common context
and vocabulary across the articles, missing metadata, supplementary
information limitations, and a concentration of both sample collection and
analysis in the United States. While some of these barriers require
significant effort to address, we also found many instances where small
choices made by authors and journals could have an outsized influence on
the discoverability and reusability of data. Promisingly, articles also
showed consistency and creativity in data storage choices as well as a
strong trend toward open access publishing. Our analysis underscores the
need to think critically about data accessibility and usability as marine
eDNA metabarcoding studies, and eDNA projects more broadly, continue to
proliferate.