Tropical carbon sink accelerated by symbiotic dinitrogen fixation.

ABSTRACT: A major uncertainty in the land carbon cycle is whether symbiotic nitrogen fixation acts to enhance the tropical forest carbon sink. Nitrogen-fixing trees can supply vital quantities of the growth-limiting nutrient nitrogen, but the extent to which the resulting carbon-nitrogen feedback safeguards ecosystem carbon sequestration remains unclear. We combine (i) field observations from 112 plots spanning 300 years of succession in Panamanian tropical forests, and (ii) a new model that resolves nitrogen and light competition at the scale of individual trees. Fixation doubled carbon accumulation in early succession and enhanced total carbon in mature forests by ~10% (~12MgC ha^-1) through two mechanisms: (i) a direct fixation effect on tree growth, and (ii) an indirect effect on the s

SUBMITTER: Levy-Varon JH 

PROVIDER: S-EPMC6904724 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature