Uni in the Brewery: Session 4
Climate Change makes life tougher for Antarctic Plants
By Sharon Robinson
Wednesday 22nd October ( 5:30pm-6:30pm )
Imagine spending 9 months a year at freezer temperatures (-20˚C) and then having 3 months of summer where the snow melts and you have almost continuous sunshine. Even then the air temperature still only gets above 0 ˚C for a few hours on the warmest days and it can still freeze at night. Pretty tough growing conditions which is why the only plants on continental Antarctica are mosses and they compete for space with lichens.
These are the conditions that are found where we are doing our research in the region around Casey Station Antarctica. |
Hear Prof.Sharon Robinson, being interviewed by Peter Riley from ABC Radio about her Uni in the Brewery presentation (the final one for 2008).
> Audio File 6.5MB
Thank you to ABC Radio Illawarra for allowing us to provide this audio file to the public! |
We have been working with colleagues at ANSTO to discover how slowly moss grows under these conditions. Radioactive carbon 14, which was released by nuclear bomb testing in the 1950s and 1960s, accumulates as the moss photosynthesises. Six cm long Antarctic moss shoots were cut into sections and dated based on how much radioactive carbon they contained. The carbon signature showed that the base of the shoots was growing before atmospheric testing started, meaning that the mosses were more than 50 years old. In good years the mosses grow on average 1.6 mm In a really tough season this drops to a mere 0.5 mm per year! Not surprisingly, growth rates are fastest in warmer years, but another important factor is how windy it is. The Antarctic ozone hole, which has led to increased ultraviolet-B (UV-B) radiation in the Antarctic spring since the 1970s, also seems to have reduced moss growth rates.
You might think that with this type of environment the moss would welcome a bit of climate change but unfortunately it seems to be making things worse. Although the region of Antarctica where we are working has not yet shown the rapid warming found in the Arctic and on the Antarctic Peninsula, climate change is having a significant effect. Climate change has led to increased wind speeds over these coastal regions and this is causing drying of the region. Increased evaporation is drying out the moss beds, which is bad news for the mosses that rely on melt water to grow. The lichens that they compete with are better suited to drier conditions and so the velvety, green moss beds that are such a feature of the Casey region may become much rarer in the future.
Just as the impact of nuclear testing in the 1950s has spread over the globe and left its signature in these tiny plants, so too the impact of climate change is being felt a long way from the source of the carbon emissions. Our research shows that climate change is truly global.
Biography
Sharon Robinson did her PHD at the University of London, followed by postdoctoral research at Duke University, N. Carolina, USA and the Australian National University in Canberra. In 1996 she took up a faculty position in Biological Sciences at the University of Wollongong and started research into climate change in Antarctica. This research is funded by the Australian Antarctic Division who also provide logistic support. Sharon has visited the Antarctic continent 5 times and sub Antarctic Macquarie Island once. She is a recognized leader in Antarctic climate change research, a subject editor for the top international journal, Global Change Biology and custodian of the only Antarctic State of the Environment Indicator for continental vegetation.
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