Phytoplankton Dynamics in an Arctic Lake

Publisher Website
Google Scholar
Abstract
Primary production measurements (C14) and phytoplankton counts were made in an arctic lake between June and September 1963. Annual carbon fixation was estimated at 8.5 g/m2 (4.0 g/m3), of which approximately 22% occurred under the ice. Phytoplankton numbers varied between 2.4 and 24.1 × 106 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.