At the center of Africa, the Congo Basin contains one of the largest and most significant of these carbon reserves. Although its peatlands and swamps cover just 0.3 percent of the planet's land surface, they store about one third of all carbon held in tropical peatlands worldwide.

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Ancient Carbon Released Into the Atmosphere

Measurements show that substantial amounts of carbon dioxide are escaping from both lakes into the atmosphere. However, the origin of that carbon was not what scientists anticipated.

While some of the emissions come from recently grown plant material, up to 40 percent of the carbon dioxide originates from peat that accumulated thousands of years ago in nearby ecosystems. Researchers determined this by analyzing the age of the dissolved CO2 using radiocarbon dating (radiocarbon dating).

"We were surprised to find that ancient carbon is being released via the lake," explains lead author Travis Drake, a scientist in the Sustainable Agroecosystem (SAE) group led by ETH Professor Johan Six. "The carbon reservoir has a leak, so to speak, from which ancient carbon is escaping," adds co-author Matti Barthel, research technician in SAE.

How Is the Carbon Being Mobilized?

Previously, scientists believed that carbon stored in Congo Basin peat remained locked away for extremely long periods and would only be released under specific conditions such as extended drought.

Exactly how this old carbon is being freed from undecomposed plant matter remains uncertain. Researchers also do not yet know the precise pathways that allow it to move from peat soils into lake water.

Posted by: Timothy Birdnow at 01:11 PM | Comments (2) | Add Comment
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