Australian researchers have discovered that chemical changes in the ocean have a significant impact on climate change.
The study, published by the University of Tasmania (UTAS) and Institute for Marine and Antarctic Studies (IMAS) on Thursday, revealed that biogeochemical changes in the ocean modulate the environmental fluctuations between glacial and interglacial periods.
Pearse Buchanan, the lead researcher from IMAS, said the study used a carbon climate model to simulate the impact of a range of ocean processes during the Last Glacial Maximum (LGM), when global ice cover reached its peak around 25,000 years ago.
"The ocean is the primary driver of climate change over thousands of years, between ice ages and warm interglacial periods, by redistributing heat and carbon stored in the ocean," Buchanan said in a media release on Thursday.
"In this study we sought to explain how the ocean was able to draw down significant amounts of carbon from the atmosphere at the time of the Last Glacial Maximum, said Buchanan.
"There were physical changes to the ocean, such as increased ventilation of dense waters in the Southern Ocean, sea-ice expansion, and cooling. But the research found that the main influence was exerted by biogeochemical changes such as ocean productivity, the way sinking organic matter is remineralized and stored in the deep ocean, and the amount of calcium carbonate produced by calcifying organisms," he explained.
He said that the research gave an insight into the mechanisms by which the ocean, and the global climate, will respond in the future as carbon levels rise.
"Once you have those physical changes in the ocean the rest of the story -- about 60 percent of the story -- for the Last Glacial Maximum can only be explained when you start incorporating fundamental changes in biogeochemical processes that occur in the ocean," he said.
"What that means is that in the future as circulation changes, sea-ice reduces and surface waters in the ocean get warmer, we also need to keep an eye on how ocean biogeochemical processes respond."
