Environmental DNA preserved in lake sediments: Calibrating a new tool for biodiversity science

English Abstract:

Biodiversity losses are a major cause of global change and could lead to significant alterations in aquatic ecosystems. Therefore, there is an urgent need to quantify biodiversity from aquatic ecosystems. Applying molecular methods to environmental DNA (eDNA) has the potential to greatly advance aquatic biodiversity science as these methods may allow for a more efficient and reproducible quantifications of biodiversity. These methods have proven to be effective in detecting endangered and invasive vertebrate and invertebrate species in water. In paleolimnology, eDNA utilization has the potential to widen the range of possible target taxa. However, more calibration is needed to elucidate the advantages and the limitations of using molecular tools in paleolimnology. The objectives of this project are then (1) to evaluate to the degree to which eDNA from sediment extracts preserve the biological dynamics apparent in the water column, and (2) to quantify the congruence between molecular approaches and traditional tools to identify taxa. To address these objectives, water samples are collected and sediment traps are deployed on a monthly basis in Cultus Lake, British Columbia. Diatoms are targeted in this study because they are adequately preserved in lake sediments and are then a suitable candidate for the calibration purpose. In addition, sockeye salmon are also studied to explore the potential of molecular methods to detect species without diagnostic features preserved in lake sediments. This study will provide great insights of the limitations and the advantages to use molecular methods to reconstruct past community dynamics.