The impact of calcifying phytoplankton on atmospheric CO2 concentration is determined by a number of factors, including their degree of ecological success as well as the buffering capacity of the ocean/marine sediment system. The relative importance of these factors has changed over Earth's history and this has implications for atmospheric CO2 and climate regulation. We explore some of these implications with four “Strangelove” experiments: two in which soft-tissue production and calcification is stopped, and two in which only calcite production is forced to stop, in idealized icehouse and greenhouse climates. We find that in the icehouse climate the loss of calcifiers compensates the atmospheric CO2 impact of the loss of all phytoplankton by roughly one-sixth. But in the greenhouse climate the loss of calcifiers compensates the loss of all phytoplankton by about half. This increased impact on atmospheric CO2 concentration is due to the combination of higher rates of pelagic calcification due to warmer temperatures and weaker buffering due to widespread acidification in the greenhouse ocean. However, the greenhouse atmospheric temperature response per unit of CO2 change to removing ocean soft-tissue production and calcification is only one-fourth that in an icehouse climate, owing to the logarithmic radiative forcing dependency on atmospheric CO2 thereby reducing the climate feedback of mass extinction. This decoupling of carbon cycle and temperature sensitivities offers a mechanism to explain the dichotomy of both enhanced climate stability and destabilization of the carbonate compensation depth in greenhouse climates.

中文翻译：

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钙化浮游植物在温室大气 CO2 调节中表现出增强的作用

钙化浮游植物对大气 CO2 浓度的影响取决于许多因素，包括它们的生态成功程度以及海洋/海洋沉积物系统的缓冲能力。这些因素的相对重要性在地球历史上发生了变化，这对大气 CO2 和气候调节产生了影响。我们通过四个“Strangelove”实验探索了其中的一些含义：两个在理想化的冰库和温室气候中，软组织生产和钙化停止，两个仅方解石生产被迫停止。我们发现，在冰库气候中，钙化剂的损失补偿了所有浮游植物损失对大气 CO2 的影响大约六分之一。但在温室气候中，钙化剂的损失补偿了所有浮游植物的损失约一半。这种对大气 CO2 浓度影响的增加是由于温度升高导致远洋钙化率较高，而温室海洋中广泛酸化导致缓冲较弱。然而，单位CO2变化对去除海洋软组织产生和钙化的温室大气温度响应仅为冰库气候的四分之一，这是由于对大气CO2的对数辐射强迫依赖，从而减少了大规模灭绝的气候反馈.