Greenhouse gas emissions from African lakes are no longer a blind spot
Alberto Borges, Loris Deirmendjian, Steven Bouillon, William Okello, Thibault Lambert, Fleur Roland, Vao Fenotiana Razanamahandry, Ny Riavo G. Voarintsoa, François Darchambeau, Ismael A. Kimirei, Jean‐Pierre Descy, George H. Allen, Cédric Morana
Abstract
Natural lakes are thought to be globally important sources of greenhouse gases (CO 2 , CH 4 , and N 2 O) to the atmosphere although nearly no data have been previously reported from Africa. We collected CO 2 , CH 4 , and N 2 O data in 24 African lakes that accounted for 49% of total lacustrine surface area of the African continent and covered a wide range of morphology and productivity. The surface water concentrations of dissolved CO 2 were much lower than values attributed in current literature to tropical lakes and lower than in boreal systems because of a higher productivity. In contrast, surface water–dissolved CH 4 concentrations were generally higher than in boreal systems. The lowest CO 2 and the highest CH 4 concentrations were observed in the more shallow and productive lakes. Emissions of CO 2 may likely have been substantially overestimated by a factor between 9 and 18 in African lakes and between 6 and 26 in pan-tropical lakes.