Discussion
In the current study, regardless of sample size (10 g, 0.5 g) and bioinformatics pipeline (ESVs, 97% OTUs, 95% OTUs) applied, we found highly comparable diatom community patterns between metabarcoding data and microscopic inventories from lake sediment samples. This was especially pronounced between the metabarcoding treatments, i.e., amplicons from 10 g and 0.5 g of DNA extracts (HTS 10 and HTS 0.5, respectively). Although the per-sample diatom richness was not significantly correlated between microscopy and metabarcoding data, community analyses indicated consistent patterns of environmental variables shaping the diatom community structures, irrespective of sample-size and bioinformatics pipeline used. This further demonstrates that metabarcoding is a viable alternative to detect diatom-environment relationships.