The marine biological pump is crucial for removing excess carbon dioxide from the atmosphere to the ocean interior and seafloor sediments. The Late Miocene Biogenic Bloom (LMBB), marked by notable increases in biogenic components in marine sediments, provides insights into the response of the biological pump to climate change. However, understanding the timing, distribution, and cause of the LMBB remains limited. We use marine barite, a refractory mineral precipitating from the water column associated with carbon export, and other proxies to reconstruct productivity in the equatorial Indian Ocean and equatorial western Atlantic between 12 and 5 Ma. Multi-proxy records reveal the onset of the LMBB in the equatorial Indian Ocean at ∼9 Ma, primarily driven by more vigorous upwelling during global cooling. We suggest that the steepened meridional temperature gradient and the Antarctic ice sheet expansion have strengthened ocean overturning, facilitating nutrient supply and biogenic bloom in upwelling regions.

中文翻译：

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赤道印度洋和赤道西大西洋晚中新世生物水华的海洋重晶石视角


海洋生物泵对于将大气中多余的二氧化碳去除到海洋内部和海底沉积物中至关重要。晚中新世生物水华 （LMBB） 以海洋沉积物中生物成分的显着增加为标志，为生物泵对气候变化的响应提供了见解。然而，对 LMBB 的时间、分布和原因的了解仍然有限。我们使用海洋重晶石（一种与碳输出相关的水柱沉淀的难熔矿物）和其他替代物来重建赤道印度洋和赤道西大西洋在 12 至 5 马 之间的生产力。多代理记录显示，LMBB 在赤道印度洋的起始高度约为 ∼9 马，主要是由全球变冷期间更剧烈的上升流驱动的。我们认为，陡峭的经向温度梯度和南极冰盖扩张加强了海洋翻转，促进了上升流地区的营养供应和生物水华。