Convergence of soil nitrogen isotopes across global climate gradients

Scientific Reports
By: , and 

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Abstract

Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the 15 N: 14 N ratio of soil organic matter across climate gradients provide key insights into understanding global patterns of N cycling. In synthesizing data from over 6000 soil samples, we show strong global relationships among soil N isotopes, mean annual temperature (MAT), mean annual precipitation (MAP), and the concentrations of organic carbon and clay in soil. In both hot ecosystems and dry ecosystems, soil organic matter was more enriched in 15 N than in corresponding cold ecosystems or wet ecosystems. Below a MAT of 9.8°C, soil δ15N was invariant with MAT. At the global scale, soil organic C concentrations also declined with increasing MAT and decreasing MAP. After standardizing for variation among mineral soils in soil C and clay concentrations, soil δ15N showed no consistent trends across global climate and latitudinal gradients. Our analyses could place new constraints on interpretations of patterns of ecosystem N cycling and global budgets of gaseous N loss.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Convergence of soil nitrogen isotopes across global climate gradients
Series title Scientific Reports
DOI 10.1038/srep08280
Volume 5
Year Published 2015
Language English
Publisher Nature Publishing Group
Publisher location London
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 8 p.; Article number: 8280
Online Only (Y/N) N
Additional Online Files (Y/N) N