How Melting Giant Icebergs May Help Slow Climate Change (Just A Little)

Melting icebergs may be fighting against the very forces that cause them to melt, a new study suggests.

Water dripping off icebergs and into the Antarctic Ocean, also known as the Southern Ocean, contains iron and other nutrients, according to research published Monday in the journal Nature Geoscience. These nutrients fertilize phytoplankton, the microscopic marine life that plays a key role in oceanic ecosystems, and help the tiny plants absorb carbon dioxide in the atmosphere as they grow into plumes.

In other words, there might be even more carbon dioxide in our atmosphere if it weren’t for the help of phytoplankton, said Dr. Grant Bigg, professor of earth system science at the University of Sheffield in England and lead author of the study.

“Previous research had shown that there was a fertilizing effect from iceberg meltwater but no one had looked at the giant icebergs in a systematic way before,” he said. “The extent, and strength, of the fertilized phytoplankton plume was the big surprise.”

For the study, Bigg and his colleagues analyzed 175 satellite images taken between 2003 and 2013 that show ocean water and at least 18-kilometer-long icebergs in the remote Antarctic Ocean. A greenish color of the water indicated high levels of phytoplankton productivity.

They noticed the colorful phytoplankton plumes in the photos extended hundreds of kilometers from giant icebergs and persisted for at least a month after the iceberg passed by. The researchers concluded that this biological process involving meltwater and phytoplankton may be responsible for up to 20 percent of the carbon that’s stored in the deep Antarctic Ocean.

“The research is important as it has shown that there is more carbon stored in the Southern Ocean than previously calculated, which will have knock-on consequences for the global carbon budget,” Bigg —> Read More