High sensitivity of tubifex for ultraviolet-B

Phytoplankton and zooplankton serve as major food material for primary and secondary consumers in the marine food web. Although phytoplankton are primary targets to UV radiation damaging effects, we have demonstrated that stratospheric ozone depletion will affect zooplankton to contribute to inhibition in biomass production. In this study, an annilid Tubifex was irradiated under UVA, UVB, UVC or direct sunlight to demonstrate behavioral changes (motility and mortality). The organism showed varying degrees of sensitivity towards UVB and UVC. Even a small increment in UVB resulted in high degree of mortality. Interestingly, water turbidity seems to have a protective effect against UV exposure. These results strongly suggest that a change in UVB flux has direct impact on biomass production.