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Is UV-B radiation affecting charophycean algae in shallow freshwater systems?
Nancy V J de Bakker1, P M van Bodegom, W H van de Poll
1Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit, de Boelelaan 1085, 1081 HV Amsterdam, the Netherlands. nancy.de.bakker@ecology.falw.vu.nl
The New Phytologist
|May 5, 2005
Summary
Charophycean algae are sensitive to ultraviolet-B (UV-B) radiation, experiencing reduced growth and increased DNA damage. While submerged, they are protected, but fluctuating water levels can expose them to harmful UV-B.
Area of Science:
- Environmental Science
- Botany
- Ecology
Background:
- Charophytes are crucial for freshwater transparency.
- Ozone depletion has led to increased UV-B radiation levels.
- Understanding UV-B effects on charophytes is vital for aquatic ecosystem health.
Purpose of the Study:
- To investigate the impact of UV-B radiation on charophycean algae.
- To assess both potential and actual UV-B effects under natural and experimental conditions.
Main Methods:
- A glasshouse experiment exposing charophytes to varying UV-B levels.
- Field measurements in Dutch freshwater systems dominated by charophytes.
- Spectroradiometrical measurements and DNA dosimeters were used.
Main Results:
- Charophytes demonstrated sensitivity to UV-B radiation, with negative effects on growth.
- UV-B exposure increased DNA damage in Chara aspera.
- No significant increase in UV-B absorbing compounds was observed, indicating a lack of protective screens.
- Field data showed rapid UV-B attenuation in water, protecting submerged vegetation.
- Fluctuating water tables can lead to intermittent UV-B exposure.
Conclusions:
- Charophytes are vulnerable to UV-B, particularly when exposed.
- Submerged charophytes are generally protected by water, but environmental changes pose risks.
- Further research is needed on charophyte adaptation and ecological consequences of UV-B exposure.