Contrasting Sensitivity of Marine Biota to UV-B Radiation Between Southern and Northern Hemispheres

Abstract

The asymmetries between hemispheres in stratospheric ozone concentration and atmospheric aerosols, leading to differences in incident ultraviolet B (UV-B) radiation, were examined in order to resolve the differential forcing of adaptation and selection of marine organisms under elevated UV-B radiation. This analysis was based on a meta-analysis including 2,060 experimental assessments of responses of marine organisms from the Northern and Southern Hemispheres to UV-B. Stratospheric ozone concentration in spring and summer decreased by 11.0 % in the Southern and 2.7 % in the Northern between 1970 and 2012, indicating higher UV-B incidence on the Southern Hemisphere. The ratio of studies on UV-B radiation impacts performed in the Southern against the Northern Hemisphere was 0.34 indicating higher research effort in the Northern Hemisphere. Responses of marine biota to UV-B indicated significantly more resistance of marine organisms tested from the Southern Hemisphere (P < 0.01) to UV-B radiation. Marine plants (angiosperm, macroalgae and microalgae) showed no significant differences in UV-B sensitivity between hemispheres, but the family Ulvaceae, showed significantly more resistance to UV-B for organisms tested from the Southern Hemisphere (P < 0.005). Echinodermata tested from the Southern Hemisphere were more resistant to UV-B (P < 0.005), as well as early stages of marine organisms (P < 0.001). Responses at the molecular and cellular level and demographic levels showed lower UV-B effects in the organisms tested from the Southern Hemisphere. The results obtained suggest that marine organisms from the Southern Hemisphere tend to be more resistant to UV-B radiation than those in the Northern Hemisphere.