DNA-based methods in paleolimnology: new opportunities for investigating long-term dynamics of lacustrine biodiversity

The emergence of DNA analyses of lake sediments has opened up many new areas of inquiry, including the study of taxa that were traditionally not considered in paleolimnology because they do not leave distinct morphological fossils. Here, we discuss the potential and challenges associated with the study of DNA in paleolimnology to address critical research questions in lacustrine ecology. We examine some recent applications by highlighting studies that have quantified centennial to millennial-scale dynamics, and that considered a diversity of planktonic groups, including bacteria, phytoplankton and zooplankton. We also summarize the main methodological precautions to be taken into account for implementing these types of DNA analyses. Based on our review of the literature focused on the analysis of DNA preserved in lake sediments, the emerging topics we have identified include: (1) the spread, establishment and effect of invasive species, (2) past fish population dynamics, (3) interactions within lacustrine communities, identified through network analyses, (4) potential application of metabarcoding for transfer functions. There are many new and exciting questions that could be addressed using DNA preserved in lake sediment and this will no doubt be an area of continued expansion in the field of paleolimnology for many years to come