Carbon exchange characteristics and their environmental effects in the northern forest ecosystem of the Greater Khingan Mountains in China

Xin Zhang; Qiuliang Zhang; Shoujia Sun; Zhihong Xu; Yanan Jian; Yue Yang; Yuan Tian; Rula Sa; Bing Wang; Fei Wang

doi:10.1016/j.scitotenv.2022.156056

Carbon exchange characteristics and their environmental effects in the northern forest ecosystem of the Greater Khingan Mountains in China

Sci Total Environ. 2022 Sep 10;838(Pt 2):156056. doi: 10.1016/j.scitotenv.2022.156056. Epub 2022 May 20.

Authors

Xin Zhang¹, Qiuliang Zhang², Shoujia Sun³, Zhihong Xu⁴, Yanan Jian⁵, Yue Yang⁶, Yuan Tian⁷, Rula Sa⁵, Bing Wang⁵, Fei Wang⁵

Affiliations

¹ Department of Forest Management, College of Forestry, Inner Mongolia Agricultural University, Hohhot 010019, China; National Field Scientific Observation and Research Station of Greater Khingan Forest Ecosystem, Inner Mongolia, Genhe 022350, China.
² Department of Forest Management, College of Forestry, Inner Mongolia Agricultural University, Hohhot 010019, China; National Field Scientific Observation and Research Station of Greater Khingan Forest Ecosystem, Inner Mongolia, Genhe 022350, China. Electronic address: 18686028468@163.com.
³ Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.
⁴ Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, Queensland 4111, Australia.
⁵ Department of Forest Management, College of Forestry, Inner Mongolia Agricultural University, Hohhot 010019, China.
⁶ Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
⁷ College of Life and Environmental Science, Huangshan University, Huangshan 245041, China.

PMID: 35605849
DOI: 10.1016/j.scitotenv.2022.156056

Abstract

Measurement and analysis of CO₂ concentration at the ecosystem scale is the basis for studying ecosystem feedback to global climate change, and it is particularly useful for understanding the processes and mechanisms of ecosystem C exchange. Through observation of CO₂ concentration at different heights, this study examined whether a CO₂ lake phenomenon exists in the Larix gmelinii ecosystem of the Greater Khingan Mountains (China), and how it might be changed and what might represent its driving factors if such a phenomenon were found to exist. Plants and soils were sampled regularly to determine δ¹³C and to quantify the proportion of C released by each component of the ecosystem. The main path of C release and the main source of CO₂ lake formation were investigated. Statistical analysis revealed that a CO₂ lake phenomenon does exist in the L. gmelinii ecosystem. Comparative analysis showed that on the daily scale, when the ecosystem was a C source, the CO₂ lake phenomenon often occurred. On the scale of the growing season, the strongest CO₂ lake was accompanied by emergence of the peak respiratory flux. Stepwise regression analysis showed that environmental factors could explain 74.87% of the CO₂ lake phenomenon. The occurrence and strength of the CO₂ lakes were found to mainly respond to changes in temperature. Linear model analysis revealed that the rate of C release from autotrophic respiration in the forest was 51.18%; the rate of C release from heterotrophic respiration during litter decomposition was 51.78%. Therefore, the C release of the L. gmelinii ecosystem is mainly from autotrophic respiration. The CO₂ released during decomposition of litter represented the main source for the formation of CO₂ lakes. The CO₂ lake effect has substantial impact on the net C flux and plays an important role in the C source/sink effect of the ecosystem.

Keywords: C exchange; C isotope composition; C release; CO(2) concentration; CO(2) lake phenomenon.

MeSH terms

Carbon Dioxide / analysis
Carbon* / analysis
China
Ecosystem*
Forests
Seasons

Substances

Carbon Dioxide
Carbon