We have irradiated cultures of the green algae Euglena gracilis in the laboratory using as irradiation source a transilluminator (peak at 312 nm, Bachhofer, Reutlingen, FRG), the spectral data of which are equal to the Philips TL 12 lamps filtered by an I

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Assessment of Euglena gracilis as a biological dosimeter for solar UVA and UVB under field conditions

Katerina Koussoulaki¹, Daniel Danielidis², D. –P. Häder³ and Regas Santas^1*

¹ OikoTechnics Institute, Kefallenias 50, Athens GR-16342

² University of Athens, Division of Ecology and Systematics, GR-15784

³ Friedrich-Alexander Universität, Staudtstr. 5, Erlangen, D-8520

^* corresponding author

KEY WORDS

Ozone depletion, flagellates, biological dosimetry, solar UVR, image analysis, Greece.

ABSTRACT

The potential of using Euglena gracilis in biological dosimetry was assessed by exposing pure cultures to filtered and unfiltered solar radiation for 3, 7 and 14 days. Cell motility and velocity were determined by a real time image analysis system. After 3 days the reduction in mean motility of E. gracilis was more dramatic under the PAR+UVA+UVB treatment, while in the PAR+UVA treatment it was intermediate (61.3%) between the PAR+UVA+UVB (37.1%) and the PAR treatments (78.4%). Cell motility was highest (88.2%) in the dark. Motility in the PAR+UVA treatment was significantly lower than in the control and PAR treatment. On day 7, motility in the PAR+UVA+UVB treatment (24.3%) was significantly lower than all other treatments. After 14 days of exposure motile cells were found in the control cultures but not in any light treatment. Evidence was found that cell mean speed tends to be higher in the presence of UVR. These assays suggest that E. gracilis is a suitable biological dosimeter for field assays of 3-10 days of full sunshine in the Mediterranean region.