In order to document relative changes in water mass contributions in the Gulf of Maine (GoM), we used the shell material of the long‐lived ocean quahog (Arctica islandica). A multicentury, crossdated master shell growth chronology facilitated the reconstruction of a radiocarbon Δ¹⁴C history prior to the radiocarbon bomb‐pulse of the 1950s. This reconstruction reveals a highly variable Δ¹⁴C series (mean = −56.6 ± 8.0‰ (1σ); N = 34) from CE 1685 to 1935. Δ¹⁴C values indicate a rapid shift ca. 1860 CE in source waters to the GoM. From CE 1685 to 1860, GoM waters were dominated by an admixture of Warm Slope Water primarily composed of tropical Atlantic surface waters/Gulf Stream Waters, and Scotian Shelf Water. This water regime was followed by a rapid Δ¹⁴C transition to a Labrador Slope Water endmember after CE 1860, with an apparent decrease in Scotian Shelf Water. Together, this shift is likely related to broader changes in the Arctic and the Labrador Sea, and a short‐term strengthening of the Atlantic meridional overturning circulation. Labrador Slope Water dominating GoM hydrography in the 1900s is verified by the similarities between this record and other coral‐ and shell‐derived Δ¹⁴C records influenced by waters with Labrador Sea origin. This suggests that GoM radiocarbon variability broadly reflects large‐scale ocean circulation processes in the Northwestern Atlantic. The lack of Δ¹⁴C values much below the Labrador Slope Water endmember suggests that the interior GoM gets very little to no Antarctic Intermediate Water as other studies had previously suggested.

中文翻译：

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缅因湾有250年历史的放射性碳年代史，在小冰河时代末期揭示了水文状况的转变

为了记录缅因州湾（GoM）中水质量贡献的相对变化，我们使用了长寿命海洋qua（Arctica islandica）的壳材料。甲multicentury，crossdated主壳生长年表促进了放射性碳Δ的重建¹⁴之前的20世纪50年代的放射性碳炸弹脉冲C的历史。此重建揭示了一个高度可变的Δ ¹⁴ C系列（平均= -56.6±8.0‰（1σ）; ñ  = 34）从CE 1685至1935Δ ¹⁴C值表示快速移动约。公元1860年在戈壁的源头水域。从公元1685年到1860年，GoM水主要由暖坡水混合而成，这些水主要由热带大西洋地表水/海湾溪流水和斯科蒂陆架水组成。这种水政权接着快速Δ ¹⁴ CE 1860后的C转变为拉布拉多斜率水端元，在斯科舍陆架水的明显减少。总之，这种转变很可能与北极和拉布拉多海的更广泛变化以及大西洋经线翻转环流的短期加强有关。拉布拉多坡水在1900主导墨西哥湾水文通过此记录及其他coral-和壳衍生Δ之间的相似性验证¹⁴受拉布拉多海起源水域影响的C记录。这表明，GoM的放射性碳变异性广泛反映了西北大西洋的大规模海洋环流过程。缺乏Δ的¹⁴ C值远低于拉布拉多水坡端员认为，内部墨西哥湾变得很少没有南极中层水和其他研究以前建议。