UNVEILING EXTREMOPHILES: EXPLORING PROTIST DIVERSITY IN CANADIAN ALKALINE SODA LAKES WITH DNA BARCODING

In Canada, the Cariboo Plateau region is home to a multitude of evaporative alkaline soda lakes. These lakes are an “extreme” environment, with high concentrations of salts and an average pH of over 10. Despite the extreme abiotic conditions, alkaline soda lakes have exceptionally high levels of primary productivity and organismal abundance and diversity. These soda lake communities are most heavily represented by filamentous cyanobacterial species, which have been studied in increasingly greater detail over the years. Many other species exist in these lakes, across all three domains of life – Bacteria, Archaea, and Eukarya. The Eukarya domain has been studied primarily at the mega- and macro-fauna levels. Microbial eukaryote species, or protists, have been heavily overlooked due in part to the assumption that protists lack cellular adaptations to survive in extreme conditions. However, molecular identification and microscopy studies have found the presence of hundreds of protistan species in these lakes.

We will be conducting a whole-community DNA barcoding study to identify protist species present in three Canadian soda lakes: Good Enough Lake, Probe Lake, and Deer Lake. This study will use three primer sets, which bind to genomic regions of interest and allow sequencing of that region for species detection, across the most used eukaryote marker gene, the 18S ribosomal RNA gene. This gene is a favourable marker gene as all eukaryotes require it for survival, and the gene has both conserved regions, for broadscale detectability through DNA barcoding, and variable regions, for species-specific identification. Primer sets have an implicit bias towards and against certain organismal genomes; by using three primer sets we aim to reduce the number of species missed through primer bias.

This study will identify protist species present in these lakes, including rare organisms, and potentially discover novel species. This study will also compare protist diversity seen across lake abiotic factors. Understanding the protist species present in these soda lakes and the evolutionary adaptations they possess to make this extreme environment habitable has important implications for understanding the evolutionary history of eukaryotes and life on Earth.