Marine Biodiversity and Ecosystems

Effects of increased Ultraviolet-B radiation on Antarctic intertebrate larvae

Principal Investigator: Dr Miles Lamare
Organisation: University of Otago

What we do: An international team of scientists lead by Dr Miles Lamare, and Associate Professor Mike Barker of the University of Otago, and Dr Michael Lesser of the University of New Hampshire have been examining the effects of Ozone Depletion and Ultraviolet Radiation (UV-R) on the Antarctic marine ecosystem. 

We are investigating the impact of UV-R on the planktonic larval stage of Sterechinus neumayeri, a species of sea urchin that is found throughout Antarctic shallow waters. Operating from Scott Base, our research involves diving under the sea ice to deploy optical instruments that measure the amount of UV-R penetrating the sea ice and water column. At the same time, we are rearing Sterechinus larvae in the laboratory for later transplantation under the ice on specially designed racks suspended at different depths. The racks have various UV-filters that allow us to quantify any harmful effects of UV-R under the sea ice. Larvae are also exposed to artificial UV-R in the laboratory to quantify specific effects of UV on development.

Why we do it: This research is challenging the assumption that marine life in Antarctica waters is protected from UV-R by the annual sea ice, that is 1-2 m thick and can cover 20 000 000 km2 of the Southern Ocean. While scientists thought that UV-R would penetrate the ice they did not expect it to be of high enough intensity to be damaging to marine life.

Some things we've found out so far: Initial results strongly indicate that this assumption is incorrect, and larval stages of Antarctic marine species might be impacted. This is particularly important given the increase in UV-R over the Antarctic continent when the ozone hole is present, and it's likely continuation for the next 25 years. The spring Ozone hole over Antarctica results in an increase in the more biologically damaging UV-radiation called UV-B, which is also responsible for skin cancer in humans. 

Early findings show that the more damaging wavelengths such as UV-B do penetrate the sea ice at intensities great enough to cause detrimental effects on the larval stages. The findings may indicate that the increase in UV-R over the Antarctic continent and surrounding oceans may have significant effects on marine life. If the delicate larval stages of sea urchins and other marine species are damaged, the lifecycle of many Antarctic species may be interrupted, with long-term impacts on the Antarctic marine ecosystem.

Recent Publications
Lesser, M.P., Thomas, T.M., Lamare, M. D. Barker, M.F. Biological weighting functions for DNA damage in sea urchin embryos exposed to ultraviolet radiation. Journal of experimental marine biology and ecology 328: 10-21, 2006.

Lesser, M.P., Lamare, M. D. Barker, M.F. Transmission of ultraviolet radiation through the Antarctic annual sea ice and its biological effects on sea urchin embryos. Limnology and Oceanography 49: 1957-1963, 2004.