Planktonic foraminifera precipitate calcite shells, which after the death of the organisms are exported to the seafloor. Globally, the resulting calcite flux constitutes up to half of the pelagic calcite flux. Given their importance for the marine calcite budget and for the carbonate counter pump, which counteracts the biological pump in terms of oceanic capacity for CO₂ uptake, it is crucial to understand the mechanisms regulating the planktonic foraminifera calcite flux. In principle, variability in individual species calcite flux could be caused by changes in (a) shell flux, (b) shell size, and (c) calcification intensity. Where size and calcification intensity differ among species, variations can be caused by changes in species composition. To assess the importance of these factors in regulating the planktonic foraminifera calcite flux, we investigated two sediment trap time series from the Cape Blanc upwelling area. On intra-annual timescales, 82% of the variability in the calcite flux can be explained by shell flux alone. Since the intra-annual flux variability at the study site covers the global range of mean annual shell fluxes, our results indicate that a global prediction of steady-state planktonic foraminifera calcite flux can be predicted by shell flux variability in combination with species-specific average shell mass. However, our results show that on inter-annual timescales, shell mass variability can be as important as shell flux variability. Therefore, this implies that in order to predict temporal changes in the planktonic foraminifera calcite flux variability in shell size and calcification intensity also require considered.

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浮游有孔虫方解石通量的决定因素：对预测年内和年间远洋碳酸盐预算的影响

浮游有孔虫沉淀方解石壳，在生物体死亡后将其输出到海底。在全球范围内，由此产生的方解石通量占远洋方解石通量的一半。鉴于它们对海洋方解石预算和碳酸盐反泵的重要性，碳酸盐反泵在 CO ₂的海洋容量方面抵消了生物泵吸收，了解调节浮游有孔虫方解石通量的机制至关重要。原则上，单个物种方解石通量的变化可能是由 (a) 壳通量、(b) 壳尺寸和 (c) 钙化强度的变化引起的。在不同物种的大小和钙化强度不同的情况下，物种组成的变化可能会导致差异。为了评估这些因素在调节浮游有孔虫方解石通量中的重要性，我们调查了来自 Cape Blanc 上涌区的两个沉积物圈闭时间序列。在年内的时间尺度上，方解石通量的 82% 的变化可以单独用壳通量来解释。由于研究地点的年内通量变化涵盖了全球年平均壳通量的范围，我们的结果表明，稳态浮游有孔虫方解石通量的全局预测可以通过壳通量变异性结合物种特定的平均壳质量来预测。然而，我们的结果表明，在年际时间尺度上，壳质量变化可能与壳通量变化一样重要。因此，这意味着为了预测浮游有孔虫方解石通量的时间变化，壳大小和钙化强度的变化也需要考虑。