Université Laval Québec, Canada
Chasing a changing Arctic Ocean: biological adjustments
Wednesday — January 12, 2011
Pacific Forum — 3:00 p.m.
Average global temperatures have increased over the last decade and temperatures in the Arctic are increasing more rapidly than elsewhere. The consequences of global warming are clear with the dramatic loss of multiyear ice and the expansion of ice free regions in summer. Beginning in the late 1990’s Canada and other countries have funded several major Arctic Oceanographic initiatives enabling yearly sampling in a number of Arctic regions. Combined data from these missions indicates that the upper ocean is freshening and becoming more stratified resulting in nitrogen becoming less available in the photic zone. Flow cytometry data indicated that the overall size distribution of bacteria was changing and that nanoplankton are being replaced by smaller eukaryotic picoplankton in the Canada Basin. Information on microbiological diversity and distribution is only now becoming available with increased sampling effort and high throughput DNA sequencing technologies.
We have collected DNA from the Amundsen Gulf region on an opportunistic basis since 2003 as part of 5 different research programs. The diversity and species composition of microbial communities, which includes phytoplankton, other protists, Bacteria, and Archaea, has shifted over a 7 year period, along with the physical oceanographic changes. The eventual outcome in terms of biological productivity and the consequences for bears, birds, and marine mammals will depend on the efficiency of nutrient transformations in the euphotic zone, the photosynthetic and heterotrophic species selected for by the new regime, and connectivity of physical space in a stratified moving water column.
Next: Pauline Yu