Size of centric diatoms as an ecological indicator

Abstract

The beautiful story of box-like diatoms, that at every division of the cell become smaller, beeause the new valves are formed inside the old ones is still usual in textbooks of Botany. There is no doubt about the reality of cycles of auxosporulation linked to eventual manges of size. But a general, regular and necessary decrease of size as generations go on, is simply not true. Many laboratories keep Skeletonema cultures over thousands of generations, without mange of diameter and without auxospore formation, and simple microscopical observation of the chains of many thick walled Melosira is evidence for the independence of diameter from the sequence of cell division. [...]