How does ocean biology affect atmospheric pCO2? Theory and models
How does ocean biology affect atmospheric pCO2? Theory and models
复制标题
海洋生物学如何影响大气中的 pCO2？
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
R. Slater
中科院分区：
文献类型：
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作者：
I. Marinov;M. Follows;A. Gnanadesikan;J. Sarmiento;R. Slater
本文研究了大气二氧化碳分压对海洋生物变化的敏感性，这些变化导致海洋表面营养物质的减少。我们发现，由于软组织泵（OCSsoft）的作用，预成形营养物质的全球库存是大气二氧化碳分压和海洋碳储量的关键决定因素。我们提出了一个新的理论，表明在大气和海洋完全平衡的条件下，大气二氧化碳分压可以写成OCSsoft指数函数的和。该理论还证明了大气二氧化碳分压对软组织泵变化的敏感性如何取决于预成型的养分库存和表面缓冲化学。我们验证了我们的理论，反对模拟在一套现实的一般循环模式（GCMs）的养分消耗。表层养分耗竭后大气二氧化碳分压的减少取决于模式中的海洋环流。通过增加垂直混合或南大洋风来增加深海通风会增加大气co2对地表养分强迫的敏感性。相反，南大洋的分层降低了大气CO2对地表养分消耗的敏感性。由于与大气气体交换缓慢，地表CO2不平衡使大气pCO2在高通风量模式下对养分耗竭更敏感，而在低通风量模式下对养分耗竭不敏感。我们的发现对过去和未来的气候都有潜在的重要意义。
[1] This paper examines the sensitivity of atmospheric pCO2 to changes in ocean biology that result in drawdown of nutrients at the ocean surface. We show that the global inventory of preformed nutrients is the key determinant of atmospheric pCO2 and the oceanic carbon storage due to the soft-tissue pump (OCSsoft). We develop a new theory showing that under conditions of perfect equilibrium between atmosphere and ocean, atmospheric pCO2 can be written as a sum of exponential functions of OCSsoft. The theory also demonstrates how the sensitivity of atmospheric pCO2 to changes in the soft-tissue pump depends on the preformed nutrient inventory and on surface buffer chemistry. We validate our theory against simulations of nutrient depletion in a suite of realistic general circulation models (GCMs). The decrease in atmospheric pCO2 following surface nutrient depletion depends on the oceanic circulation in the models. Increasing deep ocean ventilation by increasing vertical mixing or Southern Ocean winds increases the atmospheric pCO2 sensitivity to surface nutrient forcing. Conversely, stratifying the Southern Ocean decreases the atmospheric CO2 sensitivity to surface nutrient depletion. Surface CO2 disequilibrium due to the slow gas exchange with the atmosphere acts to make atmospheric pCO2 more sensitive to nutrient depletion in high-ventilation models and less sensitive to nutrient depletion in low-ventilation models. Our findings have potentially important implications for both past and future climates.