Effects of UV radiation on the RNA/DNA ratio of Copepods from Antarctica and Chile

Abstract

The effect of ultraviolet (UV) radiation on marine organisms has been an important focus of recent research, with depletion of the ozone layer resulting in increased UV radiation at high latitudes. Several studies have identified negative impacts of UV radiation on the biology of zooplanktonic organisms. This study used the RNA/DNA ratio as a measure of stress in copepod assemblages from Fildes Bay in Antarctica and Quintay Bay on the central coast of Chile, two areas with high UV radiation but different photobiologic histories. Controlled time-light experiments were performed with copepods from the two locations, exposing them to white light, UV light, or darkness. The results showed different responses to UV radiation. Copepods from Fildes Bay showed a slow metabolic response to UV radiation after 4 and 8 h of exposure. Copepods from Quintay Bay showed a fast metabolic response after 4 h of exposure (4 orders of magnitude higher than that for Fildes Bay copepods) followed by a rapid return toward baseline after 8 h of exposure. These different responses probably reflect the time the copepod assemblages have been exposed to increased UV radiation and the extent of adaptive stress responses to cope with that increased UV radiation.The results of this study show that the RNA/DNA ratio is a useful indicator of the physiologic status of marine organisms and is a useful tool to measure the effects of changing environmental conditions on marine ecosystems, such as those associated with global climate change. Citation: Lagos P F, Valdes M J, Manriquez K. Effects of UV radiation on the RNA/DNA ratio of copepods from Antarctica and Chile. Adv Polar Sci, 2015, 26: 147-157, doi: 10.13679/j.advps.2015.2.00147