Same same, but different: The response of diatoms to environmental gradients in Fennoscandian streams and lakes – barcodes, traits and microscope data compared

We developed and compared the performance of freshwater benthic diatom indices calculated from (i) traditional morphological species identification, (ii) Amplicon Sequence Variants (ASVs) obtained via DNA metabarcoding, (iii) traits to indicate eutrophication in rivers lakes Fennoscandia. Based on results, we provided recommendations for future routine use bioassessment tools environmental monitoring assessment. Our results show that ASVs are most promising candidates be used Indices based correlated better with TotP concentrations than taxa data, whereas trait least. could see by studying taxonomic assignments morphotaxa were divided up into several different ecological profiles, which explained part index also encourages further studies diversity preferences. In general, ASV- morphotaxon-specific optima differed slightly between streams lakes, but significantly each other. This means it should possible develop a common is applicable both boundary values respect might need set separately them. More knowledge required enable their