Towards standardization of DNA metabarcoding for marine
environmental monitoring
A European scale monitoring method has been identified as a science
priority need to support benthic ecosystem assessments (Van Hoey et al.,
2019). Biotic indexes inferred from DNA based taxonomic assignments are
comparable to indexes derived from morphological identifications
(Aylagas et al., 2018; Elbrecht, Vamos, et al., 2017; Lobo et al.,
2017). When using DNA metabarcoding for monitoring, a standardized
method that compares best with traditional morphological analyses in
order not to break up the existing traditional monitoring time series is
preferable. Our results show that bulk samples with use of the Leray
primer set would be the method of choice for benthic monitoring in the
North Sea. The next step is now to show case the repeatability and
robustness of DNA metabarcoding for European legislation such as the
Marine Strategy Framework Directive which may be achieved through the
organization of a ring test in which the same samples are processed by
different laboratories. Finally, our results show that complete
reference sequence databases will not be the holy grail to come to 100%
comparability with morpho-taxonomic datasets, but at this point the
reference databases are our only link with the ecological and biological
information imbedded in the Linnean system. As such, collaboration with
taxonomic experts to further populate the reference database remain
highly recommended (Porter & Hajibabaei, 2018) to benefit as much as
possible from the inclusion of DNA metabarcoding in monitoring studies.