Biology‐mediated temperature control on atmospheric pCO2 and ocean biogeochemistry
Biology‐mediated temperature control on atmospheric pCO2 and ocean biogeochemistry
复制标题
DOI：
10.1029/2007gl031301
复制
发表时间：
2007-10
影响因子：
5.2
通讯作者：
Katsumi Matsumoto
中科院分区：
文献类型：
--
作者：
Katsumi Matsumoto
在更新世的大部分时间里，冰川-间冰期大气二氧化碳水平变化与全球气候之间的显著对应表明，二氧化碳也是一个关键的气候变化驱动因素。然而，目前还没有一个被广泛接受的解释来解释冰川时期的低二氧化碳水平。在这里，我使用一个中等复杂的气候模型来表明，冰川冷却作用于海洋中有机碳产生和衰变的速度，可以解释冰川二氧化碳降低的很大一部分。新的模式结果表明，冷却加强了有机碳从海洋表层到深海的垂直运输，降低了大气中的二氧化碳分压，并将营养物质从大西洋盆地转移到印度洋-太平洋盆地。由于降温对降低下沉颗粒物有机碳降解率的作用大于降低出口产量的作用，整体垂直输送量增加。这种由生物学介导的大气pCO2的净温度效应与溶解度驱动的大气pCO2的温度效应相当，溶解度几乎总是被认为是冰川CO2水平的一个重要因素。对未来的一个暗示是，更高的海洋温度将减少碳向深海的垂直运输，从而增加海洋中二氧化碳的脱气，从而对大气中的二氧化碳起到积极的反馈作用。
The remarkable correspondence between glacial‐interglacial changes in atmospheric CO2 levels and global climate over much of the Pleistocene suggests that CO2 is also a key climate change driver. However, there is as yet no widely accepted explanation of the low glacial CO2 levels. Here I use an intermediate‐complexity climate model to show that glacial cooling, acting on the rates of organic carbon production and decay in the ocean, can explain a significant portion of the glacial CO2 lowering. New model results show that cooling strengthens the vertical transport of organic carbon from the surface ocean to the deep ocean, reduces atmospheric pCO2, and shifts nutrients from the Atlantic basin to the Indo‐Pacific basins. The overall vertical transport is increased because the cooling effect on reducing the degradation rate of sinking particulate organic carbon is greater than on reducing the export production. This net temperature effect on atmospheric pCO2 mediated by biology is comparable to the temperature effect on atmospheric pCO2 driven by solubility, which is almost always mentioned as a large factor in the glacial CO2 levels. An implication for the future is that higher ocean temperatures will act as a positive feedback on atmospheric CO2 by reducing the vertical transport of carbon to the deep ocean and thereby increasing CO2 degassing from the ocean.