Open AccessOrientation of the green flagellate, Euglena gracilis , in a vertical column of water
Author(s) -
Häder DonatP.,
Griebenow Kai
Publication year - 1988
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1988.tb02660.x
Subject(s) - flagellate , euglena gracilis , water column , phototaxis , diel vertical migration , euglena , population , column (typography) , biology , botany , ecology , chloroplast , biochemistry , connection (principal bundle) , gene , demography , structural engineering , sociology , engineering
The orientation of the green flagellate, Euglena gracilis , in a vertical column immersed in a pond was studied using automatic cell counting based on computerized image analysis. When exposed to solar radiation, the population moved downward in the column, probably guided by negative phototaxis, and formed a dense layer at the bottom. It is suggested that this behavior provides an opportunity for the organisms to escape from detrimental bright light. The downward movement is faster than the swimming speed of the cells allows and could be accelerated by a fluid mechanic effect. The upward movement observed at night may be due to the precise negative gravitaxis observed in the organisms. These antagonistic types of behavior allow the organisms to actively search for and to stay in areas with suitable conditions.