Climate change ‘visible’ in east Antarctica
East Antarctica is experiencing a significant climate change, say scientists who claim to have found an increase of “bomb spikes” in the area.
An international team says that chemical clues absorbed from the atmosphere by Antarctic mosses during nuclear tests in the 1950s and 60s, have provided it with the evidence of significant climate change in east Antarctica.
In fact, the discovery came after scientists from the University of Wollongong and the Australian Nuclear Science and Technology Organisation found that the dramatic increase in atmospheric radiocarbon (14C), known as the “bomb spike”.
Bomb spikes are detectable in living moss shoots 50 years after nuclear testing, and could be used to track changes in moss growth rates.
The team, led by Prof. Sharon Robinson, collected samples of four moss species from five sites in east Antarctica and analysed them for their 14C content.
Spikes of 14C detected in the samples were correlated with records of annual atmospheric 14C and 14C tree-ring data, which then allowed the team to calculate age of moss samples.
“Mosses grow in an incremental fashion from the shoot tip and retain a record of atmospheric carbon encountered over their photosynthetic lifespan along length of their shoots.
“In some of our moss species the peak of the radiocarbon bomb spike was found just 15 mm from the top of 50 mm shoot, suggesting that these plants may be more than 100 years old,” he said.
Having dated the moss stems the team found that growth rates varied over time and with location, between 0.2 and 3.5 mm per year.
The scientists then used another chemical signal known as 13C to track changes in water availability — which has a profound impact on moss growth.
Post new comment