利用封存在极地冰芯中的古代空气，研究人员首次提出了80万年的大气氧三同位素比率的记录，这反映了过去全球生物圈的生产力。研究人员观察到，过去八个冰川期的全球生物圈生产力低于前工业化时代的生产力，在大多数情况下，它在冰川消失前几千年开始增加。这两种变化都是与二氧化碳的变化同时发生的，这意味着二氧化碳对全球生物圈生产力的主导控制，并支持了冰川气候下普遍存在的负反馈。
据介绍，全球生物圈生产力是大气中二氧化碳的最大吸收通量，它在过去和未来的碳循环中发挥着重要作用。然而，对生物圈生产力的全球估计仍然是一个挑战。
附：英文原文
Title: Global biosphere primary productivity changes during the past eight glacial cycles
Author: Ji-Woong Yang, Margaux Brandon, Amalle Landais, Stéphanie Duchamp-Alphonse, Thomas Blunier, Frédéric Prié, Thomas Extier
Issue&Volume: 2022-03-11
Abstract: Global biosphere productivity is the largest uptake flux of atmospheric carbon dioxide (CO2), and it plays an important role in past and future carbon cycles. However, global estimation of biosphere productivity remains a challenge. Using the ancient air enclosed in polar ice cores, we present the first 800,000-year record of triple isotopic ratios of atmospheric oxygen, which reflects past global biosphere productivity. We observe that global biosphere productivity in the past eight glacial intervals was lower than that in the preindustrial era and that, in most cases, it starts to increase millennia before deglaciations. Both variations occur concomitantly with CO2 changes, implying a dominant control of CO2 on global biosphere productivity that supports a pervasive negative feedback under the glacial climate.
DOI: abj8826
Source: https://www.science.org/doi/10.1126/science.abj8826