砂漠の鉱物に隠れていた炭素循環を科学者が発見（In a first, scientists reveal an unexpected carbon cycle occurring in the Mojave Desert）

2026-09-23 カリフォルニア大学バークレー校（UCB）

＜関連情報＞

• https://ourenvironment.berkeley.edu/news/uc-berkeley-scientists-find-carbon-cycle-hiding-desert-minerals
• https://www.science.org/doi/10.1126/sciadv.aed9979

熱駆動型CO2吸着/脱着と土壌呼吸への影響 Thermally driven CO2 adsorption/desorption and its effect on soil respiration

Anna Abramova, Jennifer Mills, Gregory E. Maurer, Benjamin Gilbert, […] , and Ronald Amundson
Science Advances  Published:23 Sep 2026
DOI:https://doi.org/10.1126/sciadv.aed9979

Abstract

Soil respiration counterbalances global photosynthesis, yet several aspects of this process remain unexplained despite decades of research: (i) nighttime negative soil carbon flux in drylands and (ii) diurnal temperature-dependent hysteresis patterns. We propose that abiotic CO₂ adsorption-desorption in the soil is the cause or contributor to these phenomena. Laboratory isotherms were conducted on desert soil at various diurnal temperatures and CO₂ partial pressure levels. These results, combined with field data from the Mojave Desert, demonstrate that adsorption causes negative nocturnal CO₂ fluxes, while desorption during the day leads to positive fluxes. In addition, by accounting for thermally driven physical CO₂ exchange, the apparent temperature hysteresis commonly observed is reversed. The annual CO₂ adsorption in the thermally active soil layer ranges from 16.7 to 19.3 grams of CO₂-C per square meter per year, indicating a possible abiotic exchange of up to 2.2 to 2.5 billion tonnes of CO₂-C with the atmosphere globally. Our findings suggest that gaseous adsorption should be included in the global carbon cycle to more accurately represent land-atmosphere CO₂ exchange.