A decreasing carbon allocation to belowground autotrophic respiration in global forest ecosystems

Xiaolu Tang; Yuehong Shi; Xinruo Luo; Liang Liu; Jinshi Jian; Ben Bond-Lamberty; Dalei Hao; Alexander Olchev; Wenjie Zhang; Sicong Gao; Jingji Li

doi:10.1016/j.scitotenv.2021.149273

A decreasing carbon allocation to belowground autotrophic respiration in global forest ecosystems

Sci Total Environ. 2021 Dec 1:798:149273. doi: 10.1016/j.scitotenv.2021.149273. Epub 2021 Jul 26.

Authors

Xiaolu Tang¹, Yuehong Shi², Xinruo Luo², Liang Liu², Jinshi Jian³, Ben Bond-Lamberty⁴, Dalei Hao⁵, Alexander Olchev⁶, Wenjie Zhang⁷, Sicong Gao⁸, Jingji Li⁹

Affiliations

¹ College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, Sichuan, China; State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & WaterPollution, Chengdu University of Technology, Chengdu 610059, China. Electronic address: lxtt2010@163.com.
² College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, Sichuan, China.
³ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China; Pacific Northwest National Laboratory, Joint Global Change Research Institute at the University of Maryland-College Park, 5825 University Research Court, Suite 3500, College Park, MD 20740, USA.
⁴ Pacific Northwest National Laboratory, Joint Global Change Research Institute at the University of Maryland-College Park, 5825 University Research Court, Suite 3500, College Park, MD 20740, USA.
⁵ Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA.
⁶ Department of Meteorology and Climatology, Faculty of Geography, Lomonosov Moscow State University, GSP-1, Leninskie Gory, 119991 Moscow, Russia.
⁷ School of Geographical Sciences, Nanjing University of Information Science and Technology (NUIST), Nanjing 210044, China.
⁸ CSIRO Land and Water, PMB 2, Glen Osmond, SA 5064, Australia; Centre for Applied Water Science, University of Canberra, Canberra, Australia.
⁹ College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, Sichuan, China; State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & WaterPollution, Chengdu University of Technology, Chengdu 610059, China.

PMID: 34378544
DOI: 10.1016/j.scitotenv.2021.149273

Abstract

Belowground autotrophic respiration (RA_soil) depends on carbohydrates from photosynthesis flowing to roots and rhizospheres, and is one of the most important but least understood components in forest carbon cycling. Carbon allocation plays an important role in forest carbon cycling and reflects forest adaptation to changing environmental conditions. However, carbon allocation to RA_soil has not been fully examined at the global scale. To fill this knowledge gap, we first used a Random Forest algorithm to predict the spatio-temporal patterns of RA_soil from 1981 to 2017 based on the most updated Global Soil Respiration Database (v5) with global environmental variables; calculated carbon allocation from photosynthesis to RA_soil (CA_B) as a fraction of gross primary production; and assessed its temporal and spatial patterns in global forest ecosystems. Globally, mean RA_soil from forests was 8.9 ± 0.08 Pg C yr^-1 (mean ± standard deviation) from 1981 to 2017 and increased significantly at a rate of 0.006 Pg C yr^-2, paralleling broader soil respiration changes and suggesting increasing carbon respired by roots. Mean CA_B was 0.243 ± 0.016 and decreased over time. The temporal trend of CA_B varied greatly in space, reflecting uneven responses of CA_B to environmental changes. Combined with carbon use efficiency, our CA_B results offer a completely independent approach to quantify global aboveground autotropic respiration spatially and temporally, and could provide crucial insights into carbon flux partitioning and global carbon cycling under climate change.

Keywords: Aboveground respiration; Belowground autotrophic respiration; Carbon allocation; Carbon cycling; Gross primary production; Random forest.

MeSH terms

Carbon Cycle
Carbon*
Ecosystem*
Respiration
Soil
Trees

Substances

Soil
Carbon