Department of Earth and Environmental Sciences, Columbia University, New York, 10027, NY, USA.
Lamont-Doherty Earth Observatory, Palisades, 10964, NY, USA.
Nat Commun. 2017 Nov 23;8(1):1727. doi: 10.1038/s41467-017-01938-x.
As the largest reservoir of carbon exchanging with the atmosphere on glacial-interglacial timescales, the deep ocean has been implicated as the likely location of carbon sequestration during Pleistocene glaciations. Despite strong theoretical underpinning for this expectation, radiocarbon data on watermass ventilation ages conflict, and proxy interpretations disagree about the depth, origin and even existence of the respired carbon pool. Because any change in the storage of respiratory carbon is accompanied by corresponding changes in dissolved oxygen concentrations, proxy data reflecting oxygenation are valuable in addressing these apparent inconsistencies. Here, we present a record of redox-sensitive uranium from the central equatorial Pacific Ocean to identify intervals associated with respiratory carbon storage over the past 350 kyr, providing evidence for repeated carbon storage over the last three glacial cycles. We also synthesise our data with previous work and propose an internally consistent picture of glacial carbon storage and equatorial Pacific Ocean watermass structure.
作为在冰期-间冰期时间尺度上与大气交换碳的最大碳库，深海被认为是在更新世冰期碳封存的可能位置。尽管这一预期有很强的理论基础，但水团通风年龄的放射性碳数据存在冲突，而且关于呼吸碳库的深度、来源甚至存在的示踪剂解释也存在分歧。因为呼吸碳储存的任何变化都伴随着溶解氧浓度的相应变化，所以反映氧合作用的示踪剂数据在解决这些明显的不一致性方面很有价值。在这里，我们展示了来自太平洋中部赤道地区的铀氧化还原敏感性记录，以确定过去 350 千年来与呼吸碳储存相关的间隔，为过去三个冰川循环中反复的碳储存提供了证据。我们还将我们的数据与以前的工作进行了综合，并提出了一个关于冰川碳储存和赤道太平洋水团结构的内部一致的图景。
