Analysing size variation during light-starvation response of nutritionally diverse chrysophytes with a Coulter counter
Rottberger, Julia; Gruber, Ansgar; Kroth, Peter G.
Mixotrophy is a combination of autotrophic and heterotrophic nutrition. The regulation of the nutritional mode in mixotrophic algae is not yet fully understood. Changes in the light regime are likely to affect cell size of autotrophic, mixotrophic and heterotrophic chrysophytes to a varying extend. Here we demonstrate that an automatic particle analyser (Coulter counter) is a helpful tool not only for cell counts, but also for the detection of changes in mean cell size, total cell bio-volume or size distribution of chrysophyte cultures. The method is time saving and therefore allows large comparative studies, however, the method tends to underestimate the absolute size compared to microscopic measurements. The limitations of automated particle analysis opposed to traditional microscopical measurements are discussed exemplarily for Dinobryon divergens.