We present a high-resolution seawater radiocarbon (Δ14C) record from a Porites coral collected from Masthead Island in the southern Great Barrier Reef (GBR) covering the years 1945–2017. The Δ14C values from 1945–1953 (pre-bomb era) averaged –49‰. As a result of bomb-produced 14C in the atmosphere, Δ14C values started to rise rapidly from 1959, levelled off at ∼131‰ in the late 1970s and gradually decreased to ∼40.3‰ by 2017 due to the decrease in the air-sea 14C gradient and the overturning of the 14C ocean reservoir (i.e., surface ocean to subsurface ocean; atmosphere to surface ocean). The Masthead Island record is in agreement with previous 14C coral records from the southern GBR. A comparison between surface ocean and atmospheric Δ14C suggests that, since 2010, the main reservoir of bomb-derived 14C has shifted from the atmosphere to the surface ocean, potentially resulting in reversed 14C flux in regions where the CO2 gradient is favorable. The high-resolution Masthead coral Δ14C sheds light on long-term variability in air-sea exchange and GBR regional ocean dynamics associated with climate change and in conjunction with the previous records provides a robust seawater 14C reference series to date other carbonate samples.

中文翻译：

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大堡礁珊瑚记录中的地表海洋放射性碳：1945-2017

我们提出了一种高分辨率的海水放射性碳（Δ14C) 从一个记录门廊1945-2017 年间从大堡礁 (GBR) 南部的桅顶岛采集的珊瑚。Δ141945 年至 1953 年（炸弹前时代）的 C 值平均为 –49‰。由于炸弹产生14大气中的 C，Δ14C值从1959年开始快速上升，到1970年代后期稳定在~131‰，到2017年由于海陆空下降逐渐下降到~40.3‰14C梯度和倾覆14C 海洋水库（即地表海洋到地下海洋；大气到地表海洋）。刊头岛记录与之前的一致14来自 GBR 南部的 C 珊瑚记录。表层海洋与大气 Δ 的比较14C 建议，自 2010 年以来，炸弹衍生的主要储层14C 已从大气转移到海洋表层，可能导致逆转14CO 的区域中的 C 通量2梯度是有利的。高分辨率标头珊瑚 Δ14C揭示了与气候变化相关的海气交换和GBR区域海洋动力学的长期变化，并结合以前的记录提供了强大的海水14C 参考系列到日期的其他碳酸盐样品。