The Origins of Plankton

Abstract

IN the course of a discussion on the “Biological Problems of Fresh Water” before a joint meeting of Sections D and K of the British Association at Aberdeen (NATURE, Sept. 22, p. 467), Prof. F. E. Fritsch pointed out that one of the outstanding problems confronting workers in this field is that of discovering the origins of the many recurrent cycles of free-floating organisms (plants and animals) that occur in the surface layers of standing waters and at times populate them in such enormous numbers that they lend a definite colour to the water.