Congo basin blackwater lakes are releasing ancient carbon into the atmosphere
Science Daily
February 24, 2026
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Deep in the Congo Basin, blackwater lakes are releasing ancient carbon stored for thousands of years, challenging previous assumptions about the stability of peatlands as carbon reservoirs. A recent study published in *Nature Geoscience* reveals that these remote ecosystems, which store vast amounts of carbon, are now releasing significant amounts of CO2 into the atmosphere. Unlike previously thought, up to 40% of this carbon dioxide originates from ancient peat deposits rather than recently decomposed plant material. This discovery highlights a potential vulnerability in one of Earth's largest natural carbon sinks and raises questions about how climate change might be accelerating this process.
The research focused on two iconic blackwater lakes—Lac Mai Ndombe, the largest such lake in Africa, and Lac Tumba—situated in an ecologically critical region. These lakes are surrounded by undisturbed rainforests and swamp ecosystems that have been storing carbon for millennia. As plant debris and organic matter wash into the water, they create the characteristic dark "blackwater" hue. However, this unique environment also acts as a pathway for ancient carbon to escape. By analyzing the age of dissolved CO2 using radiocarbon dating, scientists found that significant amounts of this emissions come from peat layers accumulated thousands of years ago.
The implications of these findings are profound. While peatlands have long been considered stable carbon reservoirs, the release of ancient carbon suggests that environmental changes—such as increased drought conditions driven by climate change—could be accelerating the breakdown of
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Originally published on Science Daily on 2/24/2026