Suspended Sediment as an Attenuating Factor of Ultraviolet-B Radiation Effects on the Growth and DNA Damage of Chlorella Sp.

Abstract

Effects of enhanced ultraviolet-B (UV-B) radiation and suspended sediment (SS) separately as well as in combination on the growth and DNA damage of Chlorella sp. were studied under controlled laboratory conditions. The Chlorella sp. was exposed to UV-B of 17 µW cm-2 for 0, 1 and 5 minutes in 0, 500 and 5000 mg L-1 defined SS. The results showed that SS attenuated light penetration and suppressed the growth of Chlorella sp.. It also attenuated UV-B induced DNA damage and promoted the cell growth. The suppression and promotion of cell growth depended on the concentration of SS and dose of UV-B radiation. These results are important in understanding of the effects of elevated UV-B radiation on microalgae in sediments-dominate coastal waters.