Event Date: Thursday, January 25
Event Time: 11:00 am - 12:00 pm
Location: Shelby Auditorium

Seminars set up by University Programs faculty cover a variety of topics throughout the year. Students on and off campus are invited to attend to learn more about what is happening in the marine science community. Topics include oysters, restoration, hypoxia, and more. The majority of seminars are streamed live and archived to the Dauphin Island Sea Lab YouTube channel.


Dr. Diana Varela
Associate Professor
Department of Biology
University of Victoria, Canada

Seminar Talk: Primary Production and Silicon Biogeochemistry in the Arctic Ocean: The highs, the lows and the diatoms

Dr. Diana Varela’s research interests are centered on understanding variations in marine primary productivity and the links between phytoplankton (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.

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 fluorescent probe (PDMPO dye) as tracers of diatom production in surface waters, and from natural variations in silicon isotopes (d30Si) measured throughout the water column as indicators of diatom production and water mass distribution.


Dr. Diana Varela is a tenured Associate Professor at the University of Victoria in western 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, and a Ph.D. from the Department of Earth and Ocean Sciences at the University of British Columbia (Canada).  Prior to the start of her faculty appointment at the University of Victoria, 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, and Simon Fraser University (Canada).

While her research group’s work is mainly dedicated to fundamental studies of marine phytoplankton eco-physiology and nutrient biogeochemistry, 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.