- Drake, John E;
- Gallet‐Budynek, Anne;
- Hofmockel, Kirsten S;
- Bernhardt, Emily S;
- Billings, Sharon A;
- Jackson, Robert B;
- Johnsen, Kurt S;
- Lichter, John;
- McCarthy, Heather R;
- McCormack, M Luke;
- Moore, David JP;
- Oren, Ram;
- Palmroth, Sari;
- Phillips, Richard P;
- Pippen, Jeffrey S;
- Pritchard, Seth G;
- Treseder, Kathleen K;
- Schlesinger, William H;
- DeLucia, Evan H;
- Finzi, Adrien C
The earth's future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO₂. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade through the root-microbe-soil system; increases in the flux of C belowground under elevated CO₂ stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO₂ as a result of increases in canopy N content and higher photosynthetic N-use efficiency. The ecosystem-level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil.