The role of diatoms in primary production and silicon biogeochemistry in Arctic and Sub-Arctic Oceans

20 Juny 2017
Sala d'Actes
Impartida per: 
Dr. Diana Varela
University of Victoria, British Columbia, Canadà


During this talk, Dr. Varela will address spatial and temporal patterns in phytoplankton production and nutrient concentrations in the Arctic and sub-Arctic marine waters surrounding North America. Results from International Polar Year and other research projects (e.g. GEOTRACES, Distributed Biological Observatory) conducted during the last decade show that phytoplankton production in marine Arctic waters is highly variable from region to region, with hotspots of activity in the Chukchi Sea, the Canadian Arctic Archipelago and Baffin Bay. These high production sectors markedly contrast with the oligotrophic waters of the Canada Basin. Dr. Varela will zoom into those Arctic hotspots and describe the role of diatoms in phytoplankton production and nutrient cycling in the pan-Canadian Arctic from the sub-Arctic Pacific to the sub-Arctic Atlantic Oceans. She will present results from experimental manipulations using the radioactive 32Si isotope and a novel fluorescent probe (PDMPO dye) as tracers of diatom production in surface waters, and from natural variations in silicon isotopes (δ30Si) measured throughout the water column as indicators of diatom production and water mass distribution.


Brief biography

Dr. Diana Varela is a tenured Associate Professor at the University of Victoria (Victoria, B.C., Canada), with a joint position in the Department of Biology and the School of Earth and Ocean Sciences. Her educational background includes a ‘Licenciatura’ (equivalent to a Bachelor in Science Honours) in Biology and Oceanography at the ‘Universidad Nacional del Sur’ in Argentina, a Master of Arts from the Boston University Marine Program (USA), and a PhD. from the Department of Earth and Ocean Sciences at the University of British Columbia (Vancouver, Canada). Prior to the start of her faculty appointment at the University of Victoria in 2003, she held post-doctoral positions at the University of British Columbia and Fisheries and Oceans Canada, and was awarded a Canadian post-doctoral fellowship to work at the University of California Santa Barbara (California, USA), and Simon Fraser University (Burnaby, B.C., Canada).  Her research interests are centered on understanding variations in marine primary productivity and the links between algal (mainly diatom) physiology and nutrient cycling in the world’s ocean. Her group works from the cellular level involving phytoplankton cultures to the ecological level in natural communities, and on to a much broader oceanographic scale using natural isotopes as tracers of marine biogeochemical processes. While her lab’s work is mainly dedicated to fundamental research, they have also collaborated with industry and academic partners on applied projects. These team efforts were aimed at optimizing light systems in large-size bioreactors for aquaculture use, and assessing CO2 capture and production of value products in cyanobacteria.  Dr. Varela has extensive field experience in oceanographic expeditions to the Arctic, Antarctic, North and Equatorial Pacific, and North and South Atlantic Oceans.