The knowledge of seasonal temperature variability in the ocean is essential for understanding climate and its response to forcing factors. Time intervals with highly dynamic climate and increased seasonal forcing such as the early Holocene are of particular interest. Yet, the temporal resolution of most existing climate records is not sufficient to reconstruct temperature seasonality. Here, we present the first seasonally resolved, early Holocene, bottom-water temperature record from the Viking Bank in the northern North Sea. The reconstruction is based on the stable oxygen isotope data (δ¹⁸O_shell) of two crossdated, radiocarbon-dated subfossil shells of Arctica islandica (Bivalvia). Oxygen isotope data were combined into a 21-year long record, dated at 9593–9573 (±55) cal yr BP The record indicates an early Holocene seasonal temperature amplitude up to ca. 4.5 °C. To estimate changes in the mean state and seasonality of temperature conditions between the present and early Holocene, the record and temperatures inferred thereof are compared with modern δ¹⁸O_shell profiles and instrumental temperature data. The results indicate that the seasonal amplitude of δ¹⁸O_shell signal in the subfossil shells reflects sea-level changes. The reconstruction suggests that the long-term average and seasonal variability of temperature were similar to modern times when considering changes in the relative sea level. Our data also confirm that δ¹⁸O_shell records are reproducible and track seasonal amplitude of bottom-water temperature variability, thus demonstrate the potential for application in reconstructions of past seasonality. Furthermore, our results show that δ¹⁸O_shell records can be used to reconstruct seasonal stratification dynamics. This novel application of sclerochronological data has the potential to be used to validate and constrain paleotidal models.

了解海洋中的季节性温度变化对了解气候及其对强迫因素的响应至关重要。具有高度动态气候和增加季节性强迫的时间间隔（例如，全新世早期）尤其令人关注。然而，大多数现有气候记录的时间分辨率不足以重建温度季节性。在这里，我们展示了北海北部维京银行的第一个季节性分解的全新世早期底部水温记录。重建是基于稳定氧同位素数据（δ ¹⁸ ö_壳2 crossdated，放射性碳过时的亚化石壳的）北极蛤（Bivalvia）。氧同位素数据被合并为一个21年的长记录，日期为9593–9573（±55）yr BP。该记录表明全新世早期的季节性温度幅度高达约。4.5℃。为了估计的平均状态和当前和全新世早期之间的温度条件下的季节性变化，其推断该记录和温度与现代δ相比¹⁸ ö_壳型材和仪器的温度数据。结果表明，δ的季节性振幅¹⁸ ö_壳化石壳中的信号反映了海平面的变化。重建表明，考虑相对海平面变化时，温度的长期平均和季节性变化与现代相似。我们的数据还证实，δ ¹⁸ Ø_壳记录是重复性和跟踪底部水温变化的季节性幅度，从而表现出的潜力在过去的季节性的重建中的应用。此外，我们的结果表明，δ ¹⁸ Ø_外壳记录可以被用来重建季节性分层动态。年代学数据的这种新颖的应用有潜力用于验证和约束古潮模型。