Radiocarbon is an extremely useful carbon cycle tracer and radiometric dating tool. Here, we review the main principles and challenges involved in the use of radiocarbon in paleoceanography. First, we present a conceptual framework in which there are three possible uses of a radiocarbon measurement: (a) to obtain a calendar age interval, or a fossil entity's age; (b) to obtain an estimate of a carbon reservoir's past radiocarbon activity; or (c) to compare the relative radiocarbon activities of two contemporary carbon reservoirs. We discuss the analysis of marine fossil material, the generation of an atmospheric reference curve, and the interpretation of marine radiocarbon “ventilation metrics” in relation to this reference curve. It is emphasized that marine radiocarbon integrates the influences of: changing radiocarbon production; air-sea gas exchange effects at the sea surface; transport times within the ocean interior; and the mixing of water parcels with different transit times from the sea surface, and different sea-surface sources. These controls are what make radiocarbon such a powerful paleoceanographic tracer, though the difficulty of disentangling them is what makes marine radiocarbon dating and tracer studies so challenging. We discuss the implementation of radiocarbon in numerical models, and explore the theory linking ocean-atmosphere partitioning of radiocarbon and CO₂. Finally, we review existing records of marine radiocarbon variability over the last ∼25,000 years, which highlight the influence of ocean-atmosphere carbon exchange on past atmospheric CO₂ and climate, and point to emerging opportunities for resolving the global radiocarbon- and carbon budgets over the last glacial cycle.

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放射性碳作为古海洋学中的测年工具和示踪剂

放射性碳是一种非常有用的碳循环示踪剂和放射性测年工具。在这里，我们回顾了在古海洋学中使用放射性碳所涉及的主要原则和挑战。首先，我们提出了一个概念框架，其中放射性碳测量有三种可能的用途：（a）获得日历年龄间隔，或化石实体的年龄；(b) 估计碳储层过去的放射性碳活动；或 (c) 比较两个当代碳库的相对放射性碳活动。我们讨论了海洋化石材料的分析、大气参考曲线的生成以及与该参考曲线相关的海洋放射性碳“通风指标”的解释。强调海洋放射性碳综合了以下影响：改变放射性碳生产；海面的海气交换效应；海洋内部的运输时间；以及从海面经过不同时间、不同海面来源的水包的混合。这些控制使放射性碳成为如此强大的古海洋示踪剂，尽管难以解开它们是使海洋放射性碳测年和示踪研究如此具有挑战性的原因。我们讨论了放射性碳在数值模型中的应用，并探索了将放射性碳和 CO 的海洋-大气划分联系起来的理论 尽管解开它们的困难是使海洋放射性碳测年和示踪研究如此具有挑战性的原因。我们讨论了放射性碳在数值模型中的应用，并探索了将放射性碳和 CO 的海洋-大气划分联系起来的理论 尽管解开它们的困难是使海洋放射性碳测年和示踪研究如此具有挑战性的原因。我们讨论了放射性碳在数值模型中的应用，并探索了将放射性碳和 CO 的海洋-大气划分联系起来的理论₂ . 最后，我们回顾了过去 25,000 年海洋放射性碳变化的现有记录，这些记录突出了海洋-大气碳交换对过去大气 CO ₂和气候的影响，并指出了解决全球放射性碳和碳预算的新机会最后一个冰河周期。