We develop novel locally defined diagnostics for the efficiency of the ocean's biological pump by tracing carbon throughout its lifetime in the ocean from gas injection to outgassing and counting the number of passages through the soft-tissue and carbonate pumps. These diagnostics reveal that the biological pump's key controls on atmospheric pCO₂ are the mean number of lifetime pump passages per dissolved inorganic carbon (DIC) molecule at the surface and the mean aphotic sequestration time of regenerated DIC. We apply our diagnostics to an observationally constrained carbon-cycle model that features spatially varying stoichiometric ratios and is embedded in a data-assimilated global ocean circulation. We find that for the present-day ocean an average of 44 ± 4% of DIC in a given water parcel makes at least one lifetime passage through the soft tissue pump, and about 4% makes at least one passage through the carbonate pump. The global mean number of lifetime pump passages per molecule, including the fraction with zero passages, is and for the soft-tissue and carbonate pumps. Using idealized perturbations to sweep out a sequence of states ranging from zero biological activity ( ppmv) to complete surface nutrient depletion ( ppmv), we find that fractional changes in are dominated by fractional changes in the number of soft-tissue pump passages. At complete surface nutrient depletion, the mean fraction of DIC that has at least one lifetime passage through the soft-tissue pump increases to 69 ± 5% with .

中文翻译：

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生物碳泵的新指标：泵通道数及其对大气 pCO2 的控制

我们通过在海洋中从气体注入到除气的整个生命周期中追踪碳，并计算通过软组织和碳酸盐泵的通道数，为海洋生物泵的效率开发了新的本地定义的诊断方法。这些诊断表明生物泵对大气 pCO ₂的关键控制是表面每个溶解的无机碳 (DIC) 分子的平均寿命泵通道数和再生 DIC 的平均无光螯合时间。我们将我们的诊断应用于观测受限的碳循环模型，该模型具有空间变化的化学计量比，并嵌入到数据同化的全球海洋环流中。我们发现，对于当今的海洋，给定水包中平均 44 ± 4% 的 DIC 至少有一次通过软组织泵，大约 4% 至少有一次通过碳酸盐泵。每个分子的寿命泵通道的全局平均数，包括具有零通道的部分，是和用于软组织泵和碳酸盐泵。使用理想化扰动清除从零生物活性 ( ppmv) 到完全表面养分消耗 ( ppmv)的一系列状态，我们发现 的分数变化主要由软组织泵通道数量的分数变化决定。在表面养分完全耗尽时，至少有一次通过软组织泵的生命周期的 DIC 的平均分数增加到 69 ± 5% 。