Liang Mao-Chang, Mahata Sasadhar, Laskar Amzad H, Thiemens Mark H, Newman Sally
Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan.
Graduate Institute of Astronomy, National Central University, Taoyuan, Taiwan.
Sci Rep. 2017 Oct 13;7(1):13180. doi: 10.1038/s41598-017-12774-w.
The abundance variations of near surface atmospheric CO isotopologues (primarily OCO, OCO, OCO, and OCO) represent an integrated signal from anthropogenic/biogeochemical processes, including fossil fuel burning, biospheric photosynthesis and respiration, hydrospheric isotope exchange with water, and stratospheric photochemistry. Oxygen isotopes, in particular, are affected by the carbon and water cycles. Being a useful tracer that directly probes governing processes in CO biogeochemical cycles, ΔO (=ln(1 + δO) - 0.516 × ln(1 + δO)) provides an alternative constraint on the strengths of the associated cycles involving CO. Here, we analyze ΔO data from four places (Taipei, Taiwan; South China Sea; La Jolla, United States; Jerusalem, Israel) in the northern hemisphere (with a total of 455 measurements) and find a rather narrow range (0.326 ± 0.005‰). A conservative estimate places a lower limit of 345 ± 70 PgC year on the cycling flux between the terrestrial biosphere and atmosphere and infers a residence time of CO of 1.9 ± 0.3 years (upper limit) in the atmosphere. A Monte Carlo simulation that takes various plant uptake scenarios into account yields a terrestrial gross primary productivity of 120 ± 30 PgC year and soil invasion of 110 ± 30 PgC year, providing a quantitative assessment utilizing the oxygen isotope anomaly for quantifying CO cycling.
近地表大气CO同位素异构体（主要是(^{13}O^{12}CO)、(^{12}O^{13}CO)、(^{18}O^{12}CO)和(^{12}O^{18}CO)）的丰度变化代表了来自人为/生物地球化学过程的综合信号，这些过程包括化石燃料燃烧、生物圈的光合作用和呼吸作用、水圈与水的同位素交换以及平流层光化学。特别是氧同位素，会受到碳和水循环的影响。(\Delta^{17}O)（(=\ln(1 + \delta^{17}O)-0.516\times\ln(1 + \delta^{18}O))）作为一种直接探测CO生物地球化学循环控制过程的有用示踪剂，为涉及CO的相关循环强度提供了另一种约束。在这里，我们分析了北半球四个地点（中国台湾台北、南海、美国拉霍亚、以色列耶路撒冷）的(\Delta^{17}O)数据（总共455次测量），发现其范围相当窄（(0.326\pm0.005‰)）。保守估计陆地生物圈与大气之间的循环通量下限为(345\pm70PgC/年)，并推断出大气中CO的停留时间为(1.9\pm0.3)年（上限）。考虑各种植物吸收情况的蒙特卡罗模拟得出陆地总初级生产力为(120\pm30PgC/年)，土壤入侵量为(110\pm30PgC/年)，利用氧同位素异常对CO循环进行了定量评估。
