Identifying mechanisms driving the substantial dissolution of biogenic CaCO 3 (60 to 80%) in surface and mesopelagic waters of the global ocean is critical for constraining the surface ocean’s alkalinity and inorganic carbon budgets. We examine microzooplankton grazing on coccolithophores, photosynthetic calcifying algae responsible for a majority of open-ocean CaCO 3 production, as a mechanism driving shallow dissolution. We show that microzooplankton grazing dissolves 92 ± 7% of ingested coccolith calcite, which may explain 50 to 100% of the observed CaCO 3 dissolution in supersaturated surface waters. Microzooplankton grazing on coccolithophores is thus a substantial, previously unrecognized biological mechanism affecting the ballasting of organic carbon to deeper waters, the ecology and fitness of microzooplankton themselves due to buffering of food vacuole pH, and ultimately the continued ability of the surface ocean to take up atmospheric carbon dioxide.

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在球石藻 Emiliania huxleyi 上啃食的微型浮游动物及其在全球碳酸钙循环中的作用


确定驱动生物 CaCO 3 在全球海洋表层和中层水域大量溶解（60% 至 80%）的机制对于限制海洋表层的碱度和无机碳收支至关重要。我们研究了球石藻上的微型浮游动物吃草，球石藻是负责公海 CaCO 3 产生大部分的光合钙化藻类，作为驱动浅层溶解的机制。我们表明，微型浮游动物放牧溶解了 92% ± 7% 的摄入球石方解石，这可能解释了观察到的 CaCO 3 在过饱和地表水中溶解的 50% 到 100%。因此，在球石藻上吃掉的微型浮游动物是一种重要的、以前未被认识的生物机制，它影响有机碳到更深水域的压载，由于食物液泡 pH 值的缓冲，微浮游动物本身的生态和适应性，并最终影响了表层海洋吸收大气二氧化碳的持续能力。