Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570, Bremerhaven, Germany.
MARUM-Center for Marine Environmental Sciences, University Bremen, Leobener Strasse, 28359, Bremen, Germany.
Nat Commun. 2019 Feb 8;10(1):656. doi: 10.1038/s41467-019-08606-2.
The deglacial history of CO release from the deep North Pacific remains unresolved. This is due to conflicting indications about subarctic Pacific ventilation changes based on various marine proxies, especially for Heinrich Stadial 1 (HS-1) when a rapid atmospheric CO rise occurs. Here, we use a complex Earth System Model to investigate the deglacial North Pacific overturning and its control on ocean stratification. Our results show an enhanced intermediate-to-deep ocean stratification coeval with intensified North Pacific Intermediate Water (NPIW) formation during HS-1, compared to the Last Glacial Maximum. The stronger NPIW formation causes lower salinities and higher temperatures at intermediate depths. By lowering NPIW densities, this enlarges vertical density gradient and thus enhances intermediate-to-deep ocean stratification during HS-1. Physically, this process prevents the North Pacific deep waters from a better communication with the upper oceans, thus prolongs the existing isolation of glacial Pacific abyssal carbons during HS-1.
北太平洋深部 CO 释放的冰消期历史仍未得到解决。这是由于基于各种海洋代用指标的亚北极太平洋通风变化的指示存在冲突，特别是在 Heinrich 盛冰期 1（HS-1）期间大气 CO 迅速上升时。在这里，我们使用复杂的地球系统模型来研究冰消期北太平洋翻转及其对海洋分层的控制。我们的结果表明，与末次冰盛期相比，HS-1 期间中深层海洋分层增强，与北太平洋中层水（NPIW）的形成增强同时发生。更强的 NPIW 形成导致中深层低盐度和高温。通过降低 NPIW 的密度，这会扩大垂直密度梯度，从而在 HS-1 期间增强中深层海洋分层。从物理上讲，这个过程阻止了北太平洋深部水与上层海洋更好地交流，从而延长了 HS-1 期间存在的冰川太平洋深海碳的隔离。
