Reconstructing past ocean currents in the coastal regions is necessary to better understand the relationship between oceanographic changes and coastal ecosystems. It is known that variations have occurred with large-scale climate changes such as ENSO (El Niño Southern Oscillations) and PDO (Pacific Decadal Oscillations). Thus, reconstruction of past seawater conditions in coastal regions is needed to better understand the relationship between oceanographic changes and coastal ecosystems. Seawater radiocarbon is a unique proxy to understand the properties of water masses. Reef-building corals have been employed extensively and successfully in conducting this type of research into past ocean circulation histories. However, their distribution is limited to the low latitudes and hence alternative archives are required for studies in mid to high-latitude locations. Here, we use abalone shell samples obtained from Otsuchi Bay located in the Tohoku region on the Pacific coast of Northern Japan. Radiocarbon in abalone shells was compared with dissolved inorganic carbon in two-year-long records of river water as well as seawater. The data indicate that abalone shells can be used to reconstruct past seawater radiocarbon variations in northern Japan where coral skeletons are not available for ocean mixing studies.

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从日本大土湾获得的鲍鱼壳中记录到的东北太平洋海水放射性碳

有必要重建沿海地区过去的洋流，以更好地了解海洋变化与沿海生态系统之间的关系。众所周知，随着大规模气候变化发生变化，例如ENSO（厄尔尼诺南方涛动）和PDO（太平洋年代际涛动）。因此，需要重建沿海地区过去的海水状况，以更好地了解海洋变化与沿海生态系统之间的关系。海水放射性碳是了解水团性质的独特代表。造礁珊瑚已被广泛并成功地用于对过去的海洋环流历史进行此类研究。然而，它们的分布仅限于低纬度地区，因此在中高纬度地区进行研究需要替代档案。在这里，我们使用从位于日本北部太平洋沿岸东北地区的大土湾获得的鲍鱼壳样本。在长达两年的河水和海水记录中，将鲍鱼壳中的放射性碳与溶解的无机碳进行了比较。数据表明，鲍鱼壳可用于重建日本北部过去的海水放射性碳变化，那里的珊瑚骨骼无法用于海洋混合研究。在长达两年的河水和海水记录中，将鲍鱼壳中的放射性碳与溶解的无机碳进行了比较。数据表明，鲍鱼壳可用于重建日本北部过去的海水放射性碳变化，那里的珊瑚骨骼无法用于海洋混合研究。在长达两年的河水和海水记录中，将鲍鱼壳中的放射性碳与溶解的无机碳进行了比较。数据表明，鲍鱼壳可用于重建日本北部过去的海水放射性碳变化，那里的珊瑚骨骼无法用于海洋混合研究。