On the High Density of a Phytoplankton Population Found in a Lake under Ice

Abstract

Abstract The growth of phytoplankton in an ice‐covered lake was investigated with special reference to their photosynthetic and heterotrophic activities. Under transparent ice the photosynthetic production of organic matter was maintained enough to hold a high density of phytoplankton. When the light penetration to the water was diminished strongly by the ice‐sheet, heterotrophy contributed largely to the growth of phytoplankton.