Evaluating the Glacial‐Deglacial Carbon Respiration and Ventilation Change Hypothesis as a Mechanism for Changing Atmospheric CO2
Evaluating the Glacial‐Deglacial Carbon Respiration and Ventilation Change Hypothesis as a Mechanism for Changing Atmospheric CO2
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DOI：
10.1029/2020gl091296
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发表时间：
2020-11
影响因子：
5.2
通讯作者：
L. Stott;Jun Shao;Jimin Yu;K. Harazin
中科院分区：
文献类型：
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作者：
L. Stott;Jun Shao;Jimin Yu;K. Harazin
解释末次冰期末次冰期pCO 2上升的流行假说要求在冰期期间积累在深海中的过量呼吸碳的通风增强。最近的研究认为，冰川海洋中的[O2]较低表明碳呼吸增加。[O2]消耗的幅度在冰川最大时为100-140 µ mol/kg。由于呼吸作用与溶解无机碳（DIC）的δ 13 C相耦合，碳呼吸产生的[O2]损耗100-140 µ mol/kg将使深水δ 13 CDIC相对于地表水降低0.01 ‰。呼吸碳的长期封存也会降低深海中14 C的含量。我们表明，在晚冰期期间，太平洋深水δ 13 CDIC相对于表层海洋并没有减少，Δ 14 C仅低0.50 ‰。对冰消期间假设的通风变化的模型模拟导致δ 13 CDIC、Δ 14 C和ε 14 C的大幅增加，而这些在观测中没有记录。
The prevailing hypothesis to explain pCO2 rise at the last glacial termination calls upon enhanced ventilation of excess respired carbon that accumulated in the deep sea during the glacial. Recent studies argue lower [O2] in the glacial ocean is indicative of increased carbon respiration. The magnitude of [O2] depletion was 100–140 µ mol/kg at the glacial maximum. Because respiration is coupled to δ13C of dissolved inorganic carbon (DIC), [O2] depletion of 100–140 µ mol/kg from carbon respiration would lower deep water δ13CDIC by ∼1‰ relative to surface water. Prolonged sequestration of respired carbon would also lower the amount of 14C in the deep sea. We show that Pacific Deep Water δ13CDIC did not decrease relative to the surface ocean and Δ14C was only ∼50‰ lower during the late glacial. Model simulations of the hypothesized ventilation change during deglaciation lead to large increases in δ13CDIC, Δ14C, and ε14C that are not recorded in observations.