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标题：A considerable fraction of soil-respired CO2 is not emitted directly to the atmosphere
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作者：Enrique P. Sánchez-Cañete ; Greg A. Barron-Gafford ; Jon Chorover 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：13518
DOI：10.1038/s41598-018-29803-x
语种：English
出版社：Springer Nature
摘要：Soil CO₂ efflux ( F _soil) is commonly considered equal to soil CO₂ production ( R _soil), and both terms are used interchangeably. However, a non-negligible fraction of R _soil can be consumed in the subsurface due to a host of disparate, yet simultaneous processes. The ratio between CO₂ efflux/O₂ influx, known as the apparent respiratory quotient (ARQ), enables new insights into CO₂ losses from R _soil not previously captured by F _soil. We present the first study using continuous ARQ estimates to evaluate annual CO₂ losses of carbon produced from R _soil. We found that up to 1/3 of R _soil was emitted directly to the atmosphere, whereas 2/3 of R _soil was removed by subsurface processes. These subsurface losses are attributable to dissolution in water, biological activities and chemical reactions. Having better estimates of R _soil is key to understanding the true influence of ecosystem production on R _soil, as well as the role of soil CO₂ production in other connected processes within the critical zone.