Phosphorus Limitation on Carbon Sequestration in China under RCP8.5

Abstract

Currently, there is a lack of understanding regarding carbon (C) sequestration in China arising as a result of phosphorus (P) limitation. In this study, a global land surface model (CABLE) was used to investigate the response of C uptake to P limitation after 1901. In China, P limitation resulted in reduced net primary production (NPP), heterotrophic respiration, and net ecosystem production (NEP) in both the 2030s and the 2060s. The reductions in NEP in the period 2061–70 varied from 0.32 Pg C yr⁻¹ in China to 5.50 Pg C yr⁻¹ at the global scale, translating to a decrease of 15.0% for China and 7.6% globally in the period 2061–70, relative to the changes including C and nitrogen cycles. These ranges reflect variations in the magnitude of P limitation on C uptake (or storage) at the regional and global scales. Both in China and at the global scale, these differences can be attributed to differences in soil nutrient controls on C uptake, or positive feedback between NPP and soil decomposition rates, or both. Our results highlight the strong ability of P limitation to influence the pattern, response, and magnitude of C uptake under future conditions (2030s–2060s), which may help to clarify the potential influence of P limitation when projecting C uptake in China.

摘 要

目前,磷限制对中国和全球的碳汇和碳存储影响强度与差异缺乏系统地研究。本研究基于全球陆面模式CABLE,分析了1901年后磷限制对中国未来碳汇和碳存储变化的影响。在中国,磷限制引起了2030s和2060s的净初级生产力(NPP)、异养呼吸(HR)和净生态系统生产力(NEP)减少。相对于没有考虑磷循环过程,2061至2070年,中国与全球净初级生产力分别减少了0.32Pg C yr-1(或者15.0%)和5.50Pg C yr-1(或者7.6%)。这表明磷限制对中国碳汇的限制强度明显高于全球水平。土壤养分对碳吸收的影响差异、NPP和土壤分解速率之间的正反馈均会改变磷限制影响的强度。我们的研究强调了未来情景下磷限制对中国碳吸收有重要的影响。考虑磷限制的影响将有助于改善模式对中国碳汇评估与预估的能力。