Phytoplankton Dynamics in an Arctic Lake

• Published in: Journal of the Fisheries Research Board of Canada
• Main Author: Kalff, Jacob
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1967
• Subjects: General Medicine; Arctic; Arctic Lake; Phytoplankton
• Online Access: http://dx.doi.org/10.1139/f67-155; http://www.nrcresearchpress.com/doi/pdf/10.1139/f67-155

Primary production measurements (C 14 ) and phytoplankton counts were made in an arctic lake between June and September 1963. Annual carbon fixation was estimated at 8.5 g/m 2 (4.0 g/m 3 ), of which approximately 22% occurred under the ice. Phytoplankton numbers varied between 2.4 and 24.1 × 10 6 cells/liter. The proportion of small nannoplankton (≤ 10 μ) fluctuated between 51.0 and 100% and averaged 84.5%. Few of the organisms were larger than 20 μ. The highest numbers of phytoplankton were found near the lake bottom when between 1.20 and 1.75 m of ice covered the lake. Some evidence is provided suggesting that the organisms near the bottom lived heterotrophically when the lake was ice-covered. Insufficient light rather than nutrient deficiencies appears to have limited autotrophic carbon fixation under the ice.