Structure and Composition of Ice Algal Assemblages from the Gulf of St. Lawrence, Magdalen Islands Area

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Sève, Michèle A. De, Dunbar, Maxwell J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1990
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Weaver; Magdalen
• Online Access: http://dx.doi.org/10.1139/f90-090; http://www.nrcresearchpress.com/doi/pdf/10.1139/f90-090

Two types of ice algal assemblages were found in the Gulf of St. Lawrence: assemblages composed predominantly of pennate diatoms (abundance > 98.0%) and assemblages with a high abundance of centric diatoms (abundance > 46.2%). The first type is similar to Arctic landfast ice algal assemblages with the pennate diatoms Nitzschia cylindrus, N. polaris, and Navicula kariana as dominant species. The second type is similar to drifting ice algal assemblages previously described from the Gulf of St. Lawrence, with a percentage of centric diatom species > 46.2% due to the dominance of the planktonic diatom Thalassiosira nordenskioeldii. Species richness and the Shannon-Weaver index of diversity were low; density ranged from 10 4 –10 6 × cells∙L −1 and was negatively correlated with percent centric diatoms. Results on the structure and the composition of the ice algal assemblages are related to ice type, i.e. landfast and drifting pack ice, and compared with ice algal assemblages from higher latitudes.