Eating and growing

This large particle is covered with a bacterial biofilm, which provides a rich feeding ground for various organisms. As a Synula colony feeds on the bacteria, its member flagellates grow and divide, causing the Synula to become longer before our eyes. Between this long Synula and the particle surface, other small flagellates are absorbed in eating.

Commentary by Prof. Yuji Tsukii, Hosei University
Although the commentary of this video says “each member flagellate repeatedly divides,” no member flagellate of this Synula colony seems to be dividing in this video. In general, it takes from 30 minutes to a few hours for a flagellate cell to complete the dividing process. Therefore, it is almost impossible for us to observe cell division within the time limit of this video.

In addition, the first part of the commentary states that “a large particle provides a rich feeding ground for various organisms,” and the final part of the commentary says that “as a Synula colony feeds on bacteria, its member flagellates grow and divides.” However, there is no video evidence to support these descriptions. In the video there are scenes of various small protozoa running into this large particle, but these protozoa may not be feeding on bacteria, because most small protozoa sustain themselves through photosynthetic activity or by absorption of dissolved nutrients around them (osmotrophy).

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map