Abstract Seasonal variations in fluxes of isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs) and the estimated temperatures based on TEX 86 were examined in sinking particles collected using moored sediment traps in the eastern Atlantic upwelling regions. In the equatorial Guinea Basin, GDGT fluxes show a correlation with opal fluxes, implying that GDGTs are mainly transported via aggregation with diatoms. The flux-weighted T E X 86 H temperatures derived from particles collected both at 853 m and 3921 m depth correspond to the water temperature (24.1 °C) of ca. 50 m depth, where nitrate concentration starts to increase. This suggests that nutrient concentrations may affect the depth habitat of Thaumarchaeota, thereby influencing the TEX 86 -derived water temperatures. In the coastal upwelling off Namibia, T E X 86 H temperatures are similar to satellite-derived sea surface temperature (SST) during the warm season, but the record derived from the trap is delayed relative to the SST by approximately 26 days. Warm biases, however, occur during the cold season. Higher TEX 86 values have been found within the oxygen minimum zones (OMZs) in the water column of coastal upwelling regions. Thus, contributions from GDGTs produced in OMZs might explain the warmer temperature estimates during the cold season in regions where OMZs are pronounced. This scenario could explain the observed warm bias off Namibia. We, therefore, suggest that in the eastern Atlantic upwelling systems, nutrient depth distribution and GDGTs produced in OMZs can be potential environmental factors influencing TEX 86 in sinking particles. In paleoenvironmental records of TEX 86 , non-thermal signals have to be considered on regional scales.

中文翻译：

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TEX 86 在三个东大西洋上升流状态下沉粒子

摘要 在大西洋东部上升流区域使用系泊沉积物捕集器收集的下沉颗粒中检查了类异戊二烯甘油二烷基甘油四醚 (GDGT) 通量的季节性变化和基于 TEX 86 的估计温度。在赤道几内亚盆地，GDGT 通量显示出与蛋白石通量的相关性，这意味着 GDGT 主要通过与硅藻的聚集运输。来自在 853 m 和 3921 m 深度收集的粒子的通量加权 TEX 86 H 温度对应于约 24.1 °C 的水温 (24.1 °C)。50 m 深度，硝酸盐浓度开始增加。这表明营养浓度可能会影响奇异古菌的深度栖息地，从而影响源自 TEX 86 的水温。在纳米比亚沿海的上升流中，TEX 86 H 温度在暖季与卫星衍生的海面温度 (SST) 相似，但来自圈闭的记录相对于 SST 延迟了大约 26 天。然而，暖偏差发生在寒冷季节。在沿海上升流区域的水体中的最低氧区 (OMZ) 内发现了较高的 TEX 86 值。因此，OMZ 中产生的 GDGT 的贡献可能解释了在 OMZ 明显的地区寒冷季节期间温度估计值较高的原因。这种情况可以解释在纳米比亚附近观察到的温暖偏差。因此，我们建议在东大西洋上升流系统中，OMZ 中产生的养分深度分布和 GDGT 可能是影响下沉颗粒中 TEX 86 的潜在环境因素。在 TEX 86 的古环境记录中，