From ancient climates and human prehistory to modern-day lake pollution: a glance at the universal applicability of diatoms!
Prof. Reinhard Pienitz
09. Juin 2016
Diatoms are microscopic algae that live in tiny "glass houses", transparent cell walls with elaborate patterns of perforations that are known for their exceptional beauty which even inspired world architecture! They form the basis of major food chains and are largely responsible for the functioning and maintenance of the biogeochemical cycling of materials and energy at the planetary scale. Diatoms are excellent indicators of climatic and environmental changes which, with respect to their universality, are unsurpassed since the more than 20,000 different species display very particular ecological preferences and colonize virtually all aquatic habitats on Earth. Due to the growing volume of knowledge about their application in the aquatic sciences and the palaeo-sciences worldwide, diatoms have become a preferred tool in many laboratories with which to conduct studies in such diverse fields such as global climate change, water quality, archaeology, biogeography and biodiversity. My lecture intends to provide an array of examples of diverse research questions that can be addressed using fossilized and modern diatom records, including studies of modern-day urban lake pollution, postglacial palaeo-climates and palaeo-geography, palaeo-oceanography and human prehistory in temperate, subarctic and arctic regions of North America.
Professor in the Department of Geography, Université Laval (Québec City, Canada), Dr. Reinhard Pienitz leads the Aquatic Paleoecology Laboratory at Centre d’Études Nordiques (CEN). He supervises and co-supervises the research of graduate students and post-doctoral researchers in the fields of paleolimnology and paleoceanography, in both the Departments of geography and biology. The paleolimnologic research in his laboratory focuses on the use of fossil freshwater algae (diatoms), insects (chironomid larvae) and invertebrates (cladocera, ostracods) preserved in the sediments of arctic lakes and ponds (Labrador, Nunavik (northern Québec), Nunavut, Northwest Territories and Yukon/Alaska, Scandinavia) to reconstruct changes in climate and the environment during post-glacial times. The remains of marine diatoms and dinocysts in sedimentary deposits of coastal regions serve as indicators of changes in paleo-currents, paleoproductivity and past sea-level fluctuations in paleoceanographic studies along the Canadian West Coast, the Beaufort Sea coast (southern Arctic Ocean) and the Canadian East Coast (Labrador fjords). During past years, his research has also focused on the recovery and study of long-term climate archives from crater lake ecosystems in Nunavik (Pingualuit Crater Lake project) and southern Patagonia (PASADO project). In addition, research projects that determine the impact of animal populations (snow geese, caribous) and mining activities on the water quality of drinking water reservoirs have been completed in the Arctic, as well as assessments of the effects of urban and agricultural pollution on lakes in the Québec City region. He administers the Circumpolar Diatom Database (CDD) since 1997 and published more than 200 scientific articles, book chapters and books on diatoms and their use in the field of paleolimnology.