Flexible foliar stoichiometry reduces the magnitude of the global land carbon sink | CU Experts

Increased plant growth under elevated CO2 slows the pace of climate; warming and underlies projections of terrestrial carbon (C) and climate; dynamics. However, this important ecosystem service may be diminished by; concurrent changes to vegetation carbon to nitrogen (C:N) ratios.; Despite clear observational evidence of increasing foliar C:N under; elevated CO2 , our understanding of potential ecological consequences of; foliar stoichiometric flexibility is incomplete. Here, we illustrate; that when we incorporated CO2-driven increases in foliar stoichiometry; into the Community Land Model the projected land C sink decreased; two-fold by the end of the century compared to simulations with fixed; foliar chemistry. Further, CO2-driven increases in foliar C:N profoundly; altered Earth’s hydrologic cycle, reducing evapotranspiration and; increasing runoff; and reduced belowground N cycling rates. These; findings underscore the urgency of further research to examine both the; direct and indirect effects of changing foliar stoichiometry on soil N; cycling and plant productivity.

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