Australian National University - 28 May 2010
Ancient oceans belched stagnant CO2 into the skiesThe discovery of some of the oldest water on Earth has helped scientists understand the link between carbon stored in the Southern Ocean and the yo-yoing levels of carbon dioxide in the atmosphere. The findings could have implications for future climate research.
The researchers have analysed a sample of the southern Atlantic ocean floor close to Antarctica. They used tiny animals trapped in the mud to work out why atmospheric carbon dioxide levels rose markedly as the ice age ended around 19,500 years ago.
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The research team was able to create a chronology of ocean water mixing by studying the remains of trapped microscopic animals called foraminifera. Dr Fallon used a new single stage accelerator mass spectrometer at ANU to ‘read’ the carbon signature in the specimens that lived near the surface of the ocean, and compared this with the specimens that lived near the ocean floor. The mass spectrometer, purchased with support from the Australian Research Council, analyses the decay of carbon isotopes to determine the age of an object.
New Scientist - 05 June 2010
Ventilation of the Deep Southern Ocean and Deglacial CO2 RiseAt the end of the last ice age, atmospheric carbon dioxide levels shot up by nearly 50 per cent. But where did the CO2 come from? This long-standing climatic mystery has now been solved.
Climate scientists have suspected - but never been able to prove - that the CO2 was the result of a huge belch of gas from the oceans. They predicted that the ice age had slowed ocean circulation, trapping CO2 deep within it, and that warmer temperatures reversed this process.
Signs of stagnant CO2-rich water have now been discovered 3700 metres beneath the Southern Ocean's seabed, between Antarctica and South Africa.
- Science 28 May 2010: Vol. 328. no. 5982, pp. 1147-1151, DOI: 10.1126/science.1183627
- Science 28 May 2010: Vol. 328. no. 5982, pp. 1117-1118, DOI: 10.1126/science.1190765