Warming accelerates decomposition of decades-old carbon in forest soils

摘要

Soils store more than two times as much carbon as the atmosphere, and the vulnerability of soil carbon to warming is a critical uncertainty in predictions of 21st century climate (1). In particular, the effect of warming on the decomposition of decades-old carbon, which makes up the majority of soil carbon stocks in temperate forest soils, is highly debated (2). We took advantage of a long-term carbon isotope label in forest soils in the eastern United States to show that soil carbon fixed more than 10 y ago is just as sensitive to warming as carbon fixed more recently.