Terrestrial CO2 storage in plant biomass and soil: a negative relationship
Abstract
Elevated CO2 ( eCO2 ) experiments provide critical information to quantify the capacity of terrestrial ecosystems to store carbon. eCO2 experiments collectively suggest that nutrient limitations modulate the eCO2 fertilization effect, but a global quantification of the effects of eCO2on ecosystem-level carbon storage from eCO2 experiments is still lacking. Here, we quantify the global magnitude of the eCO2 effect on biomass and soil carbon based on data from eCO2 experiments. Nitrogen (N) and phosphorus (P) availability support a 12±3% increase in global biomass above current values, equivalent to 59±13 petagrams of carbon, for an increase in atmospheric CO2 of 250 ppm. However, the effect of eCO2 on plant biomass has a direct and negative impact on soil carbon storage. Priming effects on soil carbon can diminish the positive effects of eCO2 commonly observed in forest ecosystems, but increases in soil carbon in grasslands provide some ecosystem-level benefits on carbon storage that were previously not accounted for. Our research highlights the importance of accounting for changes in both plants and soils, and provides a mechanistic framework to quantify the land carbon sink using empirical observations.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B13E2538T
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0470 Nutrients and nutrient cycling;
- BIOGEOSCIENCES;
- 1622 Earth system modeling;
- GLOBAL CHANGE