Oceans' Carbon Release could Fuel Climate Change

It's not enough that we have to worry about human-caused greenhouse gases, but a new study now shows that nature may be contributing to climate change in its own way. With rising global temperatures, the world's oceans could start to release more carbon dioxide (CO2) into the atmosphere, fueling climate change even further.

The study, published in Nature Geoscience, provides fresh insight into how the oceans may be playing a major part in our changing climate.

Based on a 26,000-year-old sediment core taken from the Gulf of California, researchers believe the ocean's ability to take up atmospheric CO2 has changed over time.

The team, from the University of Edinburgh, measured the abundance of key elements - silicon and iron - in the fossils of tiny marine organisms, known as plankton, in the sediment core.

Plankton are a vital marine organism because they absorb CO2 from the atmosphere at the ocean surface, and can stow away vast quantities of carbon.

According to researchers, periods with when silicon was least abundant corresponded with relatively warm climates, low levels of atmospheric iron, and reduced CO2 uptake by the oceans' plankton. Scientist had suspected that iron played a part in plankton's ability to absorb CO2 - but this latest study shows that a lack of iron at the ocean surface affects other factors that contribute to plankton's carbon uptake.

"Iron is known to be a key nutrient for plankton, but we were surprised by the many ways in which iron affects the CO2 given off by the oceans," lead study author Dr. Laetitia Pichevin said in a University of Edinburgh news release. "If warming climates lower iron levels at the sea surface, as occurred in the past, this is bad news for the environment."

The Southern Ocean and equatorial Pacific and coastal areas, which are known to play a crucial role in influencing levels of CO2 in the global atmosphere, were particularly affected by this phenomenon.

Rising temperatures can indirectly increase the amount of the greenhouse gas emitted by the oceans, propelling climate change's affects further forward - a concern considering the White House's recent release of a report detailing the many ways that climate change may negatively impact Americans' health.