Trace Elements of sediment core ML1208-16BB from central equatorial Pacific@en

Quantitative constraints on deep ocean carbonate chemistry are critical for understanding the processes responsible for glacial-interglacial changes in atmospheric pCO2 and the ocean feedbacks that amplify carbon cycle change. Here, we present a new, millennially-resolved, B/Ca-based record of carbonate ion concentration (∆[CO32-]), measured on C. wullerstorfi, from central equatorial Pacific site ML1208-16BB spanning the last 35 ka. This site, bathed by Pacific Deep Water, reveals a ~24 ± 7 µmol/kg rise in deep ocean [CO32-] between ~20 and 10 ka, a larger change than previously reconstructed from sites in the western equatorial Pacific and those in the central equatorial Pacific bathed by Lower Circumpolar Deep Water.对深海碳酸盐化学体系开展定量约束研究，对于阐明驱动大气CO₂分压（pCO₂）冰期-间冰期变化的核心过程，以及放大碳循环波动的海洋反馈机制，均具备关键科学价值。本研究基于采自赤道太平洋中部站位ML1208-16BB的伍氏颗石藻（C. wullerstorfi）壳体，建立了一套全新的、千年分辨率的硼钙比（B/Ca）记录，用以重建过去35 ka以来的深海碳酸根离子浓度（∆[CO₃²⁻]）变化。该站位受太平洋深层水（Pacific Deep Water）影响，其记录显示约20 ka至10 ka期间，深海碳酸根离子浓度上升了约24±7 µmol/kg，这一变化幅度大于此前基于西赤道太平洋站位以及受环极下层水（Lower Circumpolar Deep Water）影响的赤道太平洋中部站位所重建的结果。