Researcher Profile

André Rochon

Job Title: Postdoctoral research fellow (Marine Environmental Geology)
Employer: Geological Survey of Canada (Atlantic), Bedford Institute of > Oceanography
Place of Birth: Montreal, Quebec, Canada
Public School attended: Armand Lavergne (Montreal)
High School attended: Urgel Archambault (Montreal)
Further Education: UQAM dept. of Earth Sciences (B.Sc., M.Sc.), dept. of Environmental Sciences (Ph.D.).
Geographic focus of research: Bay of Fundy, Gulf of St. Lawrence, Labrador Sea, Baffin Bay, Beaufort Sea, North Atlantic Ocean, Arctic Ocean

Brief synopsis of current research:
I am presently working on sediment cores from the Atlantic Canada region in order to reconstruct past sea-surface conditions for the most recent geological epoch, the Holocene (last 10,000 years). This is done by analyzing sediment samples at regular interval downcore for their content in dinoflagellate cysts. Dinoflagellates are planktonic algae best known for producing harmful algal blooms, or red tides, which are a serious economic and public health problem throughout the world. Some dinoflagellates form cysts which fall at the bottom of the ocean and are preserved in the sediment. By comparing the fossil with the modern dinoflagellate cyst assemblages, we are able to reconstruct the sea-surface conditions (temperature, salinity, presence of sea-ice) in which the fossil dinoflagellates lived using mathematical and statistical equations called transfer functions. The results help us in understanding the mechanisms responsible for the development of harmful algal blooms, and to understand how the Earth's climate has evolved for the last 10,000 years. The data we produce is also used by climate modelers in order to test and validate the climate simulation models used to predict future climate in the context of global warming.

This is an image of the cyst produced by the dinoflagellate Alexandrium tamarense, which forms toxic blooms that cause Paralytic Shellfish Poisoning in the Bay of Fundy and in several other coastal regions on the eastern coast of the United states and in Europe.

E-mail:
rochona@agc.bio.ns.ca

Recent Publications:

Lewis, J., Rochon, A., and Harding, I.C. 2000. Preliminary observations of cyst-theca relationships in Spiniferites ramosus and Spiniferites membranaceus (Dinophyceae). In press in Grana.

Rochon. A., de Vernal, Turon, J-L., Matthiessen, J. and Head, M.J. 1999. Distribution of recent dinoflagellate cysts in surface sediments from the North Atlantic and adjacent seas, and quantitative reconstruction of sea-surface parameters. Special Contribution Series no. 35 of the American Association of Stratigraphic Palynologists.

Rochon, A., de Vernal, A., Sejrup, H-P, and Haflidason, H. 1998. Palynological evidence of climatic and oceanographic changes in the North Sea during the last deglaciation. Quaternary Research, 49, 197-207.

de Vernal, A., Rochon, A., Turon, J.-L. and Matthiessen, J. 1997. Organic-walled dinoflagellate cysts: palynological tracers of sea-surface conditions in middle to high latitude marine environments. Geobios, 30, 905-920.

de Vernal, A., Rochon, A., Hillaire-Marcel, C., Turon, J.-L., and Guiot, J. 1993. Quantitative reconstruction of sea-surface conditions, seasonal extent of sea-ice cover and meltwater discharges in high latitude marine environments from dinoflagellate cyst assemblages. In: Peltier, R. (ed.), Ice in the Climate System, NATO Series, Vol. I, 12, 611-621.

Comments:
I chose my career because ever since I was 6-7 years old I was interested in fossils and geology in general. Geology also provided me with many opportunities to travel and be outdoors, which is what I like the most. In the summer of 1989 I worked for 3 months in the Canadian Arctic Archipelago, mostly on Ellesmere Island and Borden Island. This is the nicest place I have ever been. My main research interests are now paleoceanography (study of past oceanographic conditions) and marine palynology (study of organic microfossils in marine sediments), so I get to spend some time at sea on research vessels in order to collect sediment cores, which I also like. The ocean is one of the most important component in the Earth's climate system, but it was also important in the past and will certainly be in the future. Trying to understand how it worked in the geological times in order to try in predicting how it will affect the climate in the future is like putting together a giant puzzle. So, for those who like puzzles...