Carbon release from ocean helped end ice age »
Scientists have found a release of carbon dioxide stored deep in the ocean helped warm the planet and bring it out of the last ice age. The findings will help scientists understand how the ocean affects the carbon cycle and climate change. "The ocean currently contains about 60 times more carbon than the atmosphere - in natural conditions it is the main driver of carbon dioxide variations," said joint lead researcher, Dr Gianluca Marino, from The Australian National University (ANU) Research School of Earth Sciences. "Carbon can exchange rapidly between the ocean and the atmosphere." Atmospheric carbon dioxide levels fluctuate from around 185 parts per million (ppm) during the most recent ice age, to 280 ppm during warmer periods such as the last millennium. Since 1850 carbon dioxide levels have risen to nearly 400 ppm. The team of scientists from UK and Australia reconstructed ancient carbon dioxide levels by studying levels of the element boron in shells of microfossils recovered from the ocean floor, and compared them with the atmospheric carbon dioxide levels previously measured in ice cores from Antarctica. The team found that at the end of the last ice age, reconstructions of carbon dioxide dissolved in the ocean from tiny organisms that lived at the surface in the South Atlantic Ocean and eastern equatorial Pacific became much higher than the atmospheric levels at the time.
