Belowground carbon flux links biogeochemical cycles and resource-use efficiency at the global scale

• Published in: Ecology letters Vol. 19; no. 12; pp. 1419 - 1428
• Main Authors: Gill, Allison L., Finzi, Adrien C.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-12-2016; Wiley-Blackwell
• Subjects: Belowground carbon allocation; Biogeochemistry; Carbon - chemistry; Carbon Cycle; Databases, Factual; Ecosystem; Forest soils; Geological Phenomena; global biogeochemical cycle; Nitrogen - chemistry; nitrogen limitation; Phosphorus - chemistry; resource use efficiency; nitrogen limitation; Belowground carbon allocation; global biogeochemical cycle; resource use efficiency
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.12690

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.