Title
Marine Botany

Vertical Positioning of Diatoms

Although diatoms cannot swim, there are a whole host of biological features that allow them to influence their position in the water column. Some of these features influence the buoyancy of the cell, which determines whether they float or sink in seawater. Another has to do with the interaction of the cell with the water (drag), and the last is an environmental effect which may change dramatically from habitat to habitat.

  • Cell Size.
  • Silica.
  • Fats and Oils.
  • Test Projections.
  • Water Turbulence.

All of these factors influence the average equilibrium position of a diatom in the water. A diatom must live, on the average, at or above the critical depth, where sunlight is sufficient for photosynthesis. Natural selection has tuned all these factors to let diatoms live above that special depth.

Diatom Main Menu

Photo Gallery
Pennales
Anatomy and Morphology


copyright John Becker 1996.

Last updated: Oct. 21, 2005