Metadata standards and practical guidelines for specimen and DNA curation when building barcode reference libraries for aquatic life

Patricia Mergen (Botanical Garden of Meise, Belgium) is thanked for introducing experts who co-authored this paper. We thank Charlotte Duval and Claude Yepremian of the MNHN (Museum National d’Histoire Naturelle, Paris, France) for their comments. We acknowledge Axel Hausmann, Matthias F. Geiger and two additional anonymous reviewers for their constructive comments. This paper was written under COST Action DNAqua-Net. The European COST Action DNAqua-Net (CA 15219 https://dnaqua.net/) is a collaborative network which gathers several hundreds of scientists and water managers, with the objective of developing new genetic tools for bioassessment and monitoring of aquatic ecosystems (Leese et al. 2016). Reference libraries, together with their feasibility and quality, are one of the most important subjects of DNAqua-Net and several meetings highlighted the need to improve the reference data and maintain their quality and reliability. This has been formalised in the discussion of Weigand et al. (2019).