Coupled Coccolith-Based Temperature and Productivity High-Resolution Reconstructions in the Eastern Equatorial Pacific During the Last Deglaciation and the Holocene
Coupled Coccolith-Based Temperature and Productivity High-Resolution Reconstructions in the Eastern Equatorial Pacific During the Last Deglaciation and the Holocene
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DOI：
10.3389/fmars.2022.865846
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
M. Saavedra‐Pellitero;I. Hernández‐Almeida;E. Cabarcos;K. Baumann;T. Dunkley Jones;F. Sierro;J. Flores
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文献类型：
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作者：
M. Saavedra‐Pellitero;I. Hernández‐Almeida;E. Cabarcos;K. Baumann;T. Dunkley Jones;F. Sierro;J. Flores
我们提出了一个新的高分辨率重建的年度海表温度（SSTa）和净初级生产力（NPP）使用新的颗石藻为基础的模型开发的东赤道太平洋（EEP）。我们结合发表的coccolithophore普查计数从核心顶部在东太平洋与32个新的样本从赤道地区，推导出一个新的统计模型来重建SSTa。结果表明，新的EEP样本的添加改进了现有的基于颗石藻的SST校准，并允许以更高的置信度重建EEP中的SST a。我们还合并了深透光物种Florisphaera深在相同的表面沉积物样品的相对丰度与现有的热带地区的校准数据集，重建年度NPP。温度和生产率校准成功地应用于化石颗石数据从大洋钻探项目网站1240，在EEP。基于颗石的海表温度估计显示，在末次冰期最大期（LGM）和新仙女木期（Younger Dryas）期间冷却，并在全新世开始时变暖。这种模式不同的时间和幅度的温度变化从其他现有的SST重建的基础上地球化学和动物群代理。我们讨论这些差异是不同的代理敏感性的结果，日照强迫，季节性偏差，和/或保存文物。重建的年NPP表现出总体下降的趋势，从末次冰期晚期到近代，我们涉及到减弱风驱动的赤道上升流对全新世。我们还使用我们的SSTa和NPP重建计算了碳输出，并与相同位置的其他基于地球化学的重建进行了比较。我们的耦合SSTa-NPP重建提供了关键数据，以更全面地评估初级和出口生产力的演变以及EEP中的有机碳埋藏，并对其在冰川终端全球生物地球化学循环中的作用产生影响。
We present a new high-resolution reconstruction of annual sea-surface temperatures (SSTa) and net primary productivity (NPP) using novel coccolithophore-based models developed for the Eastern Equatorial Pacific (EEP). We combined published coccolithophore census counts from core-tops in the Eastern Pacific with 32 new samples from the Equatorial region, to derive a new statistical model to reconstruct SSTa. Results show that the addition of the new EEP samples improves existing coccolithophore-based SST-calibrations, and allow reconstructing SSTa in the EEP with higher confidence. We also merged the relative abundance of deep-photic species Florisphaera profunda in the same surface sediment samples with existing calibration datasets for tropical regions, to reconstruct annual NPP. Both temperature and productivity calibrations were successfully applied to fossil coccolith data from Ocean Drilling Project Site 1240, in the EEP. The coccolith-based SSTa estimates show a cooling during the Last Glacial Maximum (LGM) and the Younger Dryas, and warming at the start of the Holocene. This pattern differs in the timing and magnitude of the temperature changes from other available SST-reconstructions based on biogeochemical and faunal proxies. We discuss these discrepancies to be the result of different proxy sensitivities to insolation forcing, seasonal bias, and/or preservation artifacts. Reconstructed annual NPP shows a general decreasing trend from the late last glacial period to recent times, which we relate to the weakening of wind-driven equatorial upwelling towards the Holocene. We also calculated carbon export using our SSTa and NPP reconstructions, and compared to other geochemical-based reconstructions for the same location. Our coupled SSTa-NPP reconstruction provides key data to more fully assess the evolution of primary and export productivity as well as organic carbon burial in the EEP, with implications for its role in global biogeochemical cycles across glacial terminations.