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首页> 外文期刊>Paleoceanography >Plio-Pleistocene glacial-interglacial productivity changes in the eastern equatorial Pacific upwelling system
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Plio-Pleistocene glacial-interglacial productivity changes in the eastern equatorial Pacific upwelling system

机译：赤道东太平洋上升系统中的上新世更新世冰川间冰川生产力变化

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The eastern equatorial Pacific Ocean (EEP) upwelling system supports >10% of the present-day global ocean primary production, making it an important component in Earth's atmospheric and marine carbon budget. Traditionally, it has been argued that since intensification of Northern Hemisphere glaciation (iNHG, similar to 2.7Ma), changes in EEP productivity have predominantly depended on trade wind strength-controlled upwelling intensity. An alternative hypothesis suggests that EEP productivity is primarily controlled by nutrient supply from the high southern latitudes via mode waters. Here we present new high-resolution data for the latest Pliocene/early Pleistocene from Ocean Drilling Program Site 849, located within the equatorial divergence system in the heart of the EEP upwelling regime. We use carbon isotopes in benthic and planktic foraminiferal calcite and sand accumulation rates to investigate glacial-interglacial (G-IG) productivity fluctuations between 2.65 and 2.4Ma (marine isotope stages (MIS) G1 to 94). This interval includes MIS 100, 98, and 96, three large-amplitude glacials (similar to 1 in benthic O-18) representing the culmination of iNHG. Our results suggest that latest Pliocene/early Pleistocene G-IG productivity changes in the EEP were strongly controlled by nutrient supply from Southern Ocean-sourced mode waters. Our records show a clear G-IG cyclicity from MIS 100 onward with productivity levels increasing from full glacial conditions and peaking at glacial terminations. We conclude that enhanced nutrient delivery from high southern latitudes during full glacial conditions together with superimposed intensified regional upwelling toward glacial terminations strongly regulated primary productivity rates in the EEP from MIS 100 onward.
机译：赤道东部太平洋（EEP）上升流系统支持当今全球海洋初级生产量的10％以上，使其成为地球大气和海洋碳预算的重要组成部分。传统上，人们一直认为，自北半球冰期加剧（iNHG，类似于2.7Ma）以来，EEP生产率的变化主要取决于贸易风强度控制的上升强度。另一个假设表明，EEP生产率主要受南部高纬度地区通过适度水域的营养供应控制。在这里，我们介绍了位于EEP上升机制中心赤道发散系统中，来自海洋钻探计划站点849的最新上新世/早更新世的新高分辨率数据。我们在底栖和板状有孔虫方解石和砂的堆积速率中使用碳同位素来研究2.65到2.4Ma（海洋同位素阶段（MIS）G1到94）之间的冰晶间（G-IG）生产率波动。这个间隔包括MIS 100、98和96，三个大振幅冰川（类似于底栖O-18中的1个），代表了iNHG的顶点。我们的结果表明，EEP中最新的上新世/早更新世G-IG生产力变化受到来自南大洋模式水域养分供应的强烈控制。我们的记录显示，从MIS 100起，G-IG周期具有明显的周期性，而生产力水平则从充分的冰川条件开始上升，并在冰川末梢达到顶峰。我们得出的结论是，在充分的冰川条件下，来自南部高纬度地区的营养输送增加，加上朝向冰川终止的区域加剧上升，从MIS 100起强烈调节了EEP的主要生产力。

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