Cell Size Manipulation in Natural Marine, Planktonic, Diatom Communities

Abstract

In cultures of natural phytoplankton dominated by diatoms and a mixed culture of diatoms of similar species composition, the mean cell diameter selected for in species competition experiments was related to the time between limiting nutrient (ammonium) additions (i.e. temporal patchiness). Mean cell diameter increased as frequency of nutrient addition decreased. The possibility that limiting nutrient patchiness may be of some importance in cell size selection in nature is also discussed.Key words: cell size, competition, limiting nutrient patchiness, marine food chains, phytoplankton