To date, little is known about the impact of super-eruptions on ocean biogeochemistry. Using boron isotopes ratios measured on planktonic foraminifera in the marine sediment core BAR94–25, we provide a high-resolution pH record in the Andaman Sea (North of Sumatra), spanning Marine Isotopic Stage 5 to 3. This transition encompasses the super-eruption of the Toba volcano, 74,000 years ago, making it possible to decipher the potential impact of the super-eruption emissions on the ocean pH for the first time. Our results show that inferred foraminiferal pH values generally follow those predicted by glacial-interglacial CO variations. However, several abrupt pH drops coincide with Toba ash deposition. This suggests the occurrence of acidification events possibly related to Toba volcanic sulphur emission episodes. These pH drops are followed by anomalous pH increases, possibly relating to localised increases in seawater alkalinity following the alteration of large ash deposits on land.

中文翻译：

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与上次多巴火山活动相关的安达曼海海面酸化事件


迄今为止，人们对超级喷发对海洋生物地球化学的影响知之甚少。利用在海洋沉积物岩芯 BAR94-25 中的浮游有孔虫上测量的硼同位素比率，我们提供了安达曼海（苏门答腊岛北部）的高分辨率 pH 记录，跨越海洋同位素阶段 5 至 3。这一转变包括超级喷发74,000 年前的多巴火山，首次破译了超级喷发排放对海洋 pH 值的潜在影响。我们的结果表明，推断的有孔虫 pH 值通常遵循冰期-间冰期 CO 变化预测的值。然而，几次 pH 值突然下降与多巴灰沉积同时发生。这表明酸化事件的发生可能与多巴火山硫排放事件有关。 pH 值下降后，pH 值异常升高，可能与陆地上大量灰沉积物改变后海水碱度局部增加有关。