Global photosynthesis faster than thought
Thursday, 29 September 2011 Anna Salleh
Photosynthesis governs the cycling of CO2 through ocean and land plants (Source: Francisco Romero/iStockphoto)
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Speedy process Global photosynthesis is happening 25 per cent faster than previously thought - a finding that could help fine tune climate predictions, say scientists.
Atmospheric chemist Dr Colin Allison of CSIRO Marine and Atmospheric Research and colleagues report their findings today in the journal Nature.
"The refinements we propose represent a new benchmark for models to simulate carbon cycling through plants," says Allison.
Photosynthesis governs the cycling of CO2 through ocean and land plants.
To investigate the rate and amount of global photosynthesis, some previous studies have relied on extrapolating from laboratory measurements of CO2 absorption by leaves.
Other studies have analysed the chemistry of ocean sediments and ice cores to give a big picture of carbon cycling over millions of years.
The study by Allison and colleagues has drawn on 30 years of air samples taken from one tip of the planet to the other to give a finer grained picture of global photosynthesis.
Their study relied on measuring the ratio of oxygen isotopes in atmospheric CO2, which gives scientists an insight into how much photosynthesis is taking place and at what rate.
As part of their analysis, the scientists had to account for the influence of water - in particular brought about by El Niño events.
Since water influences the oxygen isotope ratio in CO2 via photosynthesis, Allison and colleagues were able to use known measurements of water and oxygen isotope ratios...