Past climate conditions predict the influence of nitrogen enrichment on the temperature sensitivity of soil respiration

Peng Tian,Qingkui Wang,Xiong Yao,Thomas W. Crowther,Zhaolin Sun,Shuli Niu,Shengen Liu,Xuechao Zhao

doi:10.1038/s43247-021-00324-2

Abstract

The response of soil carbon release to global warming is largely determined by the temperature sensitivity of soil respiration, yet how this relationship will be affected by increasing atmospheric nitrogen deposition is unclear. Here, we present a global synthesis of 686 observations from 168 field studies to investigate the relationship between nitrogen enrichment and the temperature sensitivity of soil respiration. We find that the temperature sensitivity of total and heterotrophic soil respiration increased with latitude. In addition, for total and autotrophic respiration, the temperature sensitivity responded more strongly to nitrogen enrichment with increasing latitude. Temperature and precipitation during the Last Glacial Maximum were better predictors of how the temperature sensitivity of soil respiration responds to nitrogen enrichment than contemporary climate variables. The tentative legacy effects of paleoclimate variables regulate the response through shaping soil organic carbon and nitrogen content. We suggest that careful consideration of past climate conditions is necessary when projecting soil carbon dynamics under future global change.

Highlights

The response of soil carbon release to global warming is largely determined by the temperature sensitivity of soil respiration, yet how this relationship will be affected by increasing atmospheric nitrogen deposition is unclear
It is widely demonstrated that N enrichment impacts the Q10 of soil respiration[6,7,11], but whether the global-scale effects of N enrichment on the Q10 are associated with paleoclimate needs to be validated in empirical research
With previous studies that explored the spatial variations in the Q10 of Rt at regional and larger scales, our study revealed a consistent global pattern of the in situ Q10 of Rt and Rt consists of heterotrophic (Rh) that linearly increased with latitude (Fig. 1a, b); this pattern was not revealed for Ra (Fig. 1c)

Summary

Introduction

The response of soil carbon release to global warming is largely determined by the temperature sensitivity of soil respiration, yet how this relationship will be affected by increasing atmospheric nitrogen deposition is unclear. The response of total soil respiration (Rt) to elevated temperature, which is referred to as temperature sensitivity (Q10), regulates the magnitude and direction of global C migration and its feedback to climate change[3,4,5]. The significant roles of bioclimate variables and specific microbial community in regulating N deposition effect on Q10, as well as the comparison of N deposition effects between forest and grassland ecosystems at a regional scale were revealed recently[12] These previous studies have advanced our understanding of the mechanisms underlying the N-enrichment effect on Q10. We addressed the following questions: (1) How does N enrichment affect the Q10 of Rt and its components at the global scale? (2) Whether the paleoclimate could predict the N-enrichment effects on Q10 better than the contemporary climate? (3) How does the paleoclimate directly and indirectly regulate the effects of N enrichment on the Q10 of Rt and its components?

Methods

Results

Conclusion