Climate‐dependent CO 2 emissions from lakes

Inland waters, just as the world's oceans, play an important role in the global carbon cycle. While lakes and reservoirs typically emit CO 2 , they also bury carbon in their sediment. The net CO 2 emission is largely the result of the decomposition or preservation of terrestrially supplied carbon. What regulates the balance between CO 2 emission and carbon burial is not known, but climate change and temperature have been hypothesized to influence both processes. We analyzed patterns in carbon dioxide partial pressure ( p CO 2 ) in 83 shallow lakes over a large climatic gradient in South America and found a strong, positive correlation with temperature. The higher p CO 2 in warmer lakes may be caused by a higher, temperature‐dependent mineralization of organic carbon. This pattern suggests that cool lakes may start to emit more CO 2 when they warm up because of climate change.