Department of Geology and Geophysics, Texas A&M University, College Station, USA.
Department of Earth, Ocean and Atmospheric Sciences, Old Dominion University, Norfolk, USA.
Sci Rep. 2020 Apr 20;10(1):6606. doi: 10.1038/s41598-020-63628-x.
Ventilation of carbon stored in the deep ocean is thought to play an important role in atmospheric CO increases associated with Pleistocene deglaciations. The presence of this respired carbon has been recorded by an array of paleoceanographic proxies from various locations across the global ocean. Here we present a new sediment core from the Eastern Equatorial Pacific (EEP) Ocean spanning the last 180,000 years and reconstruct high-resolution Th-derived fluxes of Th and excess barium, along with redox-sensitive uranium concentrations to examine past variations in dust delivery, export productivity, and bottom-water oxygenation, respectively. Our bottom-water oxygenation record is compared to other similar high-resolution records from across the Pacific and in the Southern Ocean. We suggest that the deep Pacific is a site of respired carbon storage associated with periods of decreased global atmospheric CO concentration during the LGM, confirming the conclusions from a wealth of previous studies. However, our study is the first to show a similar relationship beyond the last glacial, extending to at least 70,000 years.
储存在深海中的碳的通风被认为在与更新世冰消期相关的大气 CO 增加中起着重要作用。这种被呼吸的碳的存在已经被来自全球海洋各个位置的一系列古海洋学代理记录下来。在这里，我们展示了一个来自东赤道太平洋（EEP）海洋的新的沉积岩芯，跨越了过去的 180000 年，并重建了高分辨率的 Th 衍生通量的 Th 和过剩钡，以及氧化还原敏感的铀浓度，分别检查过去尘埃输送、出口生产力和底层水氧合的变化。我们的底层水氧合记录与来自太平洋和南大洋的其他类似高分辨率记录进行了比较。我们认为，太平洋深部是与 LGM 期间全球大气 CO 浓度降低相关的呼吸碳储存的场所，这证实了大量先前研究的结论。然而，我们的研究首次表明，这种关系不仅存在于末次冰期之后，而且至少延伸到了 7 万年前。
