Molecular approaches are revolutionizing the analysis and assessment of marine pelagic assemblages and enabling simultaneous detection of diversity from microbes to mammals. Emerging results indicate that global estimates of pelagic diversity will markedly increase with more accurate detection of rare, cryptic and introduced species, as well as a higher resolution of time/space patterns. As high-throughput DNA sequencing (HTS) becomes more accessible and less expensive, the use of metabarcoding (i.e., large-scale taxonomic identification of complex environmental samples via analysis of orthologous DNA regions) may expand into numerous applications in ocean research, monitoring, and management and be critically important in allowing the rapid detection and description of climate change impacts on pelagic biodiversity and biogeography.
Among the challenges remaining for the reliable and routine application of metabarcoding are the evaluation and comparison of results using different genes and gene regions, the impacts of degraded DNA (e.g. environmental DNA and DNA recovered from gut contents), and the continued development of reference databases for all gene regions. A particular need is to move metabarcoding applications from identifying and detecting taxa to quantifying them in terms of abundance and/or biomass.
Despite the remarkable promise of metabarcoding in yielding new understanding and appreciation for global patterns of biodiversity, it is critically important to maintain expertise and capacity in morphological taxonomy across the many groups represented in the marine pelagic assemblage.
The application of metabarcoding approaches for ecosystem observation will require validation, ground-truthing, and standardization. Integrative morphological and molecular taxonomic approaches can provide a foundation for research, monitoring, and management o the pelagic realm.
Topics of particular interest for papers in this session include:
- Comparison of morphological and metabarcoding analyses; accuracy and resolution of MOTU (Molecular Operational Taxonomic Unit) designations
- Environmental DNA (eDNA) analysis
- Metabarcoding analysis of trophic interactions and pelagic foodweb dynamics
- Approaches toward quantitative analysis of taxon abundance or biomass
- Prospects for metabarcoding analysis of species-level biodiversity for metazoans
- Applications for time-series collections and long-term ecosystem observing
- Standardization and/or intercomparison of protocols for ecosystem monitoring and assessment, including calculation of biotic indices and detection of introduced invasive species
