Assessing environmental quality in a historically polluted fjord, a comparison of benthic meiofaunal eDNA and morphospecies approaches

This study is the first assessment of foraminifera (meiofauna) diversity using sedimentary eDNA from one of the most polluted fjords in Scandinavia, comparing the assemblage response reported by morphology-based and molecular ecosystem assessment techniques.Although genetic data processing decisions influence the EcoQS assessment category determined by each technique, both datasets report congruous responses in the benthic foraminiferal assemblages to pollution and environmental stress factors. Genetic methods tend to overestimate EcoQS at highly anoxic sites probably due to a presence of dormant propagules or extraorganismal DNA, suggesting that morphological methods would still be necessary for EcoQS assessment in such conditions.