Down‐core changes in the coiling direction of Globorotalia truncatulinoides in the northwestern subtropical Atlantic (KNR140‐37PC and Ocean Drilling Program Sites 1063, 1059, 1056, 1058) provide a tracer for the hydrographic conditions in the western boundary current over the past 700 kyr (Marine Isotope Stage, MIS, 1–17). A consistent association between percent G. truncatulinoides (sinistral) abundances, total test counts, and bulk sediment CaCO₃ content is established by MIS 11 suggesting a response to ocean‐atmosphere interactions during the mid Brunhes event. Commencing with MIS 11, interglacial maxima are associated with high total test counts and either distinct sinistral test minima (MIS 9e, 11c) or maxima (MIS 1, 5e, 7a). High sinistral test abundances with relatively high test counts is similar to the late Holocene relationship at the study sites. Low sinistral test abundances despite high test counts means that coiling ratios are dominated by dextral forms. We interpret this pattern to indicate more intense flow in the subtropical gyre either via the western boundary current drawing toward the gyre center, or a more northern influence of the North Equatorial and Antilles Currents. This suggests that the western boundary current may have been more intense during MIS 11c and MIS 9e then during MIS 7a, MIS 5e, and MIS 1 consistent with climate warm anomalies in northern Europe at these times. Regardless of the mechanism, the observation that minima and maxima in sinistral test abundances are prolonged at these times indicates that the western gyre boundary remained stable during relative warm intervals.

中文翻译：

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从globorotalia truncatulinoides的卷曲比重建过去700 Kyr在北大西洋的西部边界洋流稳定性

在卷绕方向向下核心变化Globorotalia truncatulinoides在西北大西洋热带（KNR140-37PC和大洋钻探计划网站1063，1059，1056，1058）在西边界流，在过去700 KYR水文条件提供示踪剂（海洋同位素阶段，MIS，1-17）。截短的G. truncatulinoides（正弦）丰度百分比，总测试计数和大量沉淀物CaCO ₃之间的一致性MIS 11建立了内容，建议在布鲁日中旬事件期间对海洋-大气相互作用做出反应。从MIS 11开始，冰间最大值与高总测试计数以及明显的鼻窦测试最小值（MIS 9e，11c）或最大值（MIS 1，5e，7a）相关。较高的鼻窦检测丰度和较高的检测计数类似于研究地点晚新世的关系。尽管测试次数多，但鼻窦测试的丰度却低，这意味着卷曲比主要由右旋形式决定。我们将这种模式解释为表明，通过向边界中心的西边界洋流或北赤道和安的列斯洋流向北的影响，表明亚热带涡流中有更强烈的流动。这表明与MIS 8a，MIS 5e和MIS 1期间相比，MIS 11c和MIS 9e期间的西部边界流可能更强，这与这些时期北欧的气候温暖异常一致。不管机理如何，在这些时间观察到的鼻窦测试丰度的最小值和最大值都会延长，这表明西回旋边界在相对温暖的时间间隔内保持稳定。