The effects of ultraviolet-a (UV-A) on UMT marine phytoplankton

Abstract

Marine phytoplankton is responsible for sequestering an estimated 104 Giga ton carbon per year which is approximately half the photosynthetic production on Earth. Phytoplankton mostly occupies the water surface or photic zone where ultraviolet-A radiation is highest. Scientific concern over ozone depletion in the upper atmosphere has prompted extensive efforts to assess the potential damage to life on Earth due to increased levels of UV radiation. Therefore, 7 species of natural phytoplankton population from University Malaysia Terengganu's beach and 2 species of monoalgal culture have been used to determine the effect of ultraviolet-A radiation on its growth rate, growth dynamic and cell division time. Results showed that there is no significant difference (p>0.05) in the growth dynamic except for Gymnodinium sp. However, there is slight effect of ultraviolet-A on their growth rate and cell division time where species exposed to ultraviolet-A have lower growth rates and higher cell divison time compared to species exposed to non ultraviolet-A radiation. Overall, the results indicate that ultraviolet-A radiation does not have acute effect on natural phytoplankton population.