Nutrient limitation is pervasive in the terrestrial biosphere, although the relationship between global carbon (C) nitrogen (N) and phosphorus (P) cycles remains uncertain. Using meta-analysis we show that gross primary production (GPP) partitioning belowground is inversely related to soil-available N : P, increasing with latitude from tropical to boreal forests. N-use efficiency is highest in boreal forests, and P-use efficiency in tropical forests. High C partitioning belowground in boreal forests reflects a 13-fold greater C cost of N acquisition compared to the tropics. By contrast, the C cost of P acquisition varies only 2-fold among biomes. This analysis suggests a new hypothesis that the primary limitation on productivity in forested ecosystems transitions from belowground resources at high latitudes to aboveground resources at low latitudes as C-intensive root- and mycorrhizal-mediated nutrient capture is progressively replaced by rapidly cycling, enzyme-derived nutrient fluxes when temperatures approach the thermal optimum for biogeochemical transformations.
Bibliographical noteFunding Information:
We are grateful for comments from Andrew Black, Damien Bonal, Fred Bosveld, Larry Flanagan, Damiano Gianelle, Leonardo Montagnani, Andrew Richardson, Olivier Roupsard, Francesco Vaccari and Georg Wolhfahrt. We appreciate in-depth reviews from Benjamin Houlton, Michael Ryan, William Schlesinger, Benjamin Turner and Ying-Ping Wang. Principal funding for this research was provided to ACF by the Department of Energy (DOE), Office of Science (Grant No. SC0006916 & DE-SC0012288) and to ALG via the DOE Graduate Fellowship Program administered by Oak Ridge Institute for Science and Education (ORISE). ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE contract number DE-AC05-06OR23100. FLUXNET funding comes from: AmeriFlux (U.S. Department of Energy, Biological and Environmental Research, Terrestrial Carbon Program (DE-FG02-04ER63917 and DE-FG02-04ER63911)), AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, FLUXNET-Canada (supported by CFCAS, NSERC, BIOCAP, Environment Canada, and NRCan), GreenGrass, KoFlux, LBA, NECC, OzFlux, TCOS-Siberia, USCCC. We acknowledge the financial support to the eddy covariance data harmonisation provided by CarboEurope IP, FAO-GTOS-TCO, iLEAPS, Max Planck Institute for Biogeochemistry, National Science Foundation, University of Tuscia, Universite Laval, Environment Canada, and US Department of Energy and the database development and technical support from Berkeley Water Center, Lawrence Berkeley National Laboratory, Microsoft Research eScience, Oak Ridge National Laboratory, University of California-Berkeley and the University of Virginia. All opinions expressed in this paper are the authors’ and do not necessarily reflect the policies and views of DOE, ORAU or ORISE.
© 2016 John Wiley & Sons Ltd/CNRS
- Belowground carbon allocation
- global biogeochemical cycle
- nitrogen limitation
- resource use efficiency