High diversity of freshwater invertebrates on inuinnait nuna, the canadian arctic, revealed using mitochondrial DNA barcodes

Knowledge of genetic and species-level diversity for freshwater invertebrates in the Canadian Arctic is currently limited. Here, we sampled benthic and planktonic invertebrates from 68 ponds, seven lakes, and six rivers near Cambridge Bay (Iqaluktuuttiaq), Nunavut, between 2018 and 2021 and analysed individuals using mitochondrial cytochrome c oxidase subunit 1 (COI) gene sequences. From the 9336 specimens collected, 7186 provided sequences > 400 base pairs (83% success rate), representing 3358 unique haplotypes and 467 putative species based on Barcode Index Numbers (BINs; as a surrogate for species-level diversity). Chironomidae (non-biting midges) was the most diverse taxon, followed by Trombidiformes mites and Anomopoda (water fleas). Species’ accumulation curves for total diversity as well as the major taxa suggest that taxa we identified represent < 63% of the total diversity likely to be found in this region of the western Canadian Arctic (estimated n = 739) during the ice-free season. Further sampling over a wider geographical range as well as assessments of temporal (seasonal and inter-annual) variability will be required to assess comprehensively the total species richness currently found in the Canadian Arctic. In the interim, the publicly available data we provide here can be used as a baseline for ongoing studies and to track ecological changes occurring in aquatic habitats of the central Canadian Arctic and beyond.