Modern biogeochemical conditions of the Eastern Equatorial Pacific (EEP) region are characterized by high macronutrient concentrations but low phytoplankton abundance due to both iron and silicic acid limitation. Since primary producers significantly impact the global carbon cycle, paleoproductivity in relation to climate change and nutrient availability in this region has been a topic of a number of studies. However, the complex dynamics of this region, especially east of the Galapagos Islands, has led to some discrepancies when linking reconstructed paleoproductivity with potential mechanisms for higher primary productivity. Here we focus on reconstructing primary productivity of haptophyte algae and diatoms, as well as continental material input, sea surface salinity, and sea surface temperature, and compare these reconstructions with existing records for the period comprised between 150 and 110 ka (the penultimate deglaciation period) with the aim to understand the mechanisms that most significantly influence phytoplankton growth over the EEP region east of the Galapagos Islands. Our results suggest enhanced upwelling in the EEP system during the penultimate deglaciation and increased phytoplankton abundance mainly as the result of both the increasing influence of nutrient‐rich Southern Ocean sourced waters through the Equatorial Undercurrent and a higher input of iron through atmospheric deposition. The highest phytoplankton abundances recorded at the study site during the penultimate deglaciation also suggest that maximum input of nutrients might have occurred during the millennial‐scale event Heinrich Event 11 in the North Atlantic as a result of global atmospheric and oceanic reorganizations.

中文翻译：

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倒数第二次冰期期间，赤道东太平洋，加拉帕戈斯群岛以东的初级生产力控制

赤道东太平洋地区（EEP）的现代生物地球化学条件的特征是高营养素含量高，但由于铁和硅酸的限制，浮游植物的丰度低。由于初级生产者对全球碳循环产生重大影响，因此该地区与气候变化和养分供应相关的古生产力已成为许多研究的主题。但是，该地区，特别是加拉帕戈斯群岛以东地区的复杂动态，在将重建的古生产力与提高初级生产力的潜在机制联系起来时，导致了一些差异。在这里，我们专注于重建触藻藻和硅藻的初级生产力，以及大陆物质输入，海面盐度和海面温度，并将这些重建物与150至110 ka（倒数第二次冰消期）期间的现有记录进行比较，以了解最显着影响加拉帕戈斯群岛以东EEP地区浮游植物生长的机理。我们的结果表明，在倒数第二次冰期期间，EEP系统的上升流增强，浮游植物的丰度增加，这主要是由于营养丰富的南大洋源水通过赤道暗流影响的增加和大气沉积物中铁的​​输入增加的结果。