In assessing biological UV-B effects, natural fluctuations of solar radiation should be taken into account

• Published in: Plant ecology 1997, Vol.128 (1/2), p.93-97
• Main Authors: Santas, R, Koussoulaki, A, Hader, D.P
• Format: Article
• Language: English
• Subjects: Biodiversity; Bromides; diurnal variation; dose response; ecosystems; Fluctuations; Light; Mathematical minima; measurement; Ozone; Photosynthetically active radiation; plant communities; Plant ecology; Plants; pollution; Radiation dosage; Sensors; Solar radiation; stress response; Ultraviolet radiation; UV-B and Terrestrial Ecosystems: General and Methodological Aspects; Visible spectrum; Wavelengths
• ISSN: 1385-0237; 1573-5052
• DOI: 10.1023/A:1009717226788

Daily and weekly fluctuations of PAR, UV-A, and UV-B have been continuously monitored for 5 months in Ancient Korinthos, Greece (37°58′ N, 23°0′ E) using a calibrated instrument based on 3 sharp band sensors. Daily dose ranged between$521-12006\text{kJ}\text{m}^{-2}$for PAR; 52-1,$239\text{kJ}\text{m}^{-2}$for UV-A; and 0.66-22.5 kJ m⁲ for UV-B. Weekly dose ranged between 16 778-81$788\text{kJ}\text{m}^{-2}$for PAR; 1 406-8$517\text{kJ}\text{m}^{-2}$for UV-A; and$18-151\text{kJ}\text{m}^{-2}$for UV-B. UV-B/PAR and UV-A/PAR ratio distribution, however, does not follow closely PAR fluctuations. Generally, the UV-B/PAR and UV-A/PAR ratios were high in bright light conditions ($2.1\times 10^{-3}$,$118\times 10^{-3}$) and low in darker weeks ($0.9\times 10^{-3}$,$63\times 10^{-3}$). The UV-B/UV-A ratio exhibits smaller fluctuations with season ($20\text{x}1\times 10^{-3}$,$12\times 10^{-3}$). Attention is drawn to the effects of sudden changes in ambient radiation and to the ratios of UV-B, UV-A, and PAR.