College of Resources, Sichuan Agricultural University, 211 Huiming Road, Wenjiang District, Chengdu 611130, Sichuan, China.
The Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Dongxiaofu No.2, Haidian District, Beijing 100091, China.
Sci Rep. 2016 Nov 29;6:37864. doi: 10.1038/srep37864.
Comparisons of soil respiration (R) and its components of heterotrophic (R) and rhizospheric (R) respiration during daytime and nighttime, growing (GS) and dormant season (DS), have not being well studied and documented. In this study, we compared R, R, R, and their responses to soil temperature (T) and moisture (θ) in daytime vs. nighttime and GS vs. DS in a subalpine forest in 2011. In GS, nighttime R and R rates were 30.5 ± 4.4% (mean ± SE) and 30.2 ± 6.5% lower than in daytime, while in DS, they were 35.5 ± 5.5% and 37.3 ± 8.5% lower, respectively. DS R and R accounted for 27.3 ± 2.5% and 27.6 ± 2.6% of GS R and R, respectively. The temperature sensitivities (Q) of R and R were higher in nighttime than daytime, and in DS than GS, while they all decreased with increase of T. Soil C fluxes were more responsive to θ in nighttime than daytime, and in DS than GS. Our results suggest that the DS and nighttime R play an important role in regulating carbon cycle and its response to climate change in alpine forests, and therefore, they should be taken into consideration in order to make accurate predictions of R and ecosystem carbon cycle under climate change scenarios.
关于土壤呼吸（R）及其异养（R）和根际（R）呼吸组成部分在白天和夜间、生长季（GS）和休眠季（DS）的比较，尚未得到很好的研究和记录。在这项研究中，我们于 2011 年在亚高山森林中比较了 R、R、R 及其对白天与夜间和 GS 与 DS 土壤温度（T）和水分（θ）的响应。在 GS 中，夜间 R 和 R 的速率比白天分别低 30.5±4.4%（平均值±标准误差）和 30.2±6.5%，而在 DS 中，分别低 35.5±5.5%和 37.3±8.5%。DS 的 R 和 R 分别占 GS 的 R 和 R 的 27.3±2.5%和 27.6±2.6%。R 和 R 的温度敏感性（Q）在夜间高于白天，在 DS 高于 GS，而随着 T 的增加，它们都降低。土壤 C 通量对θ的响应在夜间高于白天，在 DS 高于 GS。我们的研究结果表明，DS 和夜间 R 在调节高山森林碳循环及其对气候变化的响应方面发挥着重要作用，因此，为了在气候变化情景下对 R 和生态系统碳循环做出准确预测，应该考虑它们。
