Biologists find signs of DNA damage in Antarctic fish
SYDNEY, Australia (AP) _ Ultraviolet light pouring through the hole in the ozone layer that opens over Antarctica each year is causing DNA damage in a species of icefish, biologists have found.
The discovery of lesions in the DNA of icefish off the Antarctic Peninsula that stretches toward the tip of South America builds on research that found genetic damage in tiny single-celled plants in the same region.
The work by Kirk Malloy and William Detrich of Northeastern University in Boston was supported by the U.S. National Science Foundation, which funds research ships and scientific bases in Antarctica.
``Ozone depletion has previously been shown to harm one-celled marine plants in Antarctica,″ Detrich said. ``We’ve now documented significant damage at a higher level of the food chain.″
The ultraviolet-B light shining through the ozone hole caused a surprising number of lesions in the eggs and larvae of icefish, they found.
So far, no DNA damage has been found in penguins, seals or other higher animals, but the work on icefish confirms a trend found in smaller, simpler one-celled plants.
Detrich and Malloy next plan to see if the DNA damage in icefish hampers their survival.
Excess ultraviolet light may slow a fish’s growth, interfere with cellular processes and divert precious energy to DNA repair, they said.
``Increased UV-B may ultimately let fewer larvae survive to adulthood,″ Malloy said.
A thin layer of ozone in the Earth’s upper atmosphere screens out most UV-B radiation, but it has thinned over the Arctic and Antarctic in recent decades as manmade gases called chlorofluorocarbons rose into the stratosphere.
A hole forms over Antarctica each southern spring, cutting ozone levels in half and letting more UV-B light reach the ground.
The ozone layer has also thinned, but to a lesser extent, in temperate climates. UV-B light can cause skin cancers and glaucoma.