scholarly journals Carbon isotope records reveal precise timing of enhanced Southern Ocean upwelling during the last deglaciation

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Giuseppe Siani ◽  
Elisabeth Michel ◽  
Ricardo De Pol-Holz ◽  
Tim DeVries ◽  
Frank Lamy ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Carbon Isotope ◽  
Last Deglaciation ◽  
Precise Timing ◽  
The Last Deglaciation

scholarly journals Hydrographic shifts south of Australia over the last deglaciation and possible interhemispheric linkages

2021 ◽  
pp. 1-12
Author(s):  
Matthias Moros ◽  
Patrick De Deckker ◽  
Kerstin Perner ◽  
Ulysses S. Ninnemann ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Southern Hemisphere ◽  
Critical Role ◽  
Temperature Response ◽  
South Australia ◽  
Last Deglaciation ◽  
Tight Coupling ◽  
Oceanic Fronts ◽  
The Last Deglaciation ◽  
Circumpolar Current

Abstract Northern and southern hemispheric influences—particularly changes in Southern Hemisphere westerly winds (SSW) and Southern Ocean ventilation—triggered the stepwise atmospheric CO2 increase that accompanied the last deglaciation. One approach for gaining potential insights into past changes in SWW/CO2 upwelling is to reconstruct the positions of the northern oceanic fronts associated with the Antarctic Circumpolar Current. Using two deep-sea cores located ~600 km apart off the southern coast of Australia, we detail oceanic changes from ~23 to 6 ka using foraminifer faunal and biomarker alkenone records. Our results indicate a tight coupling between hydrographic and related frontal displacements offshore South Australia (and by analogy, possibly the entire Southern Ocean) and Northern Hemisphere (NH) climate that may help confirm previous hypotheses that the westerlies play a critical role in modulating CO2 uptake and release from the Southern Ocean on millennial and potentially even centennial timescales. The intensity and extent of the northward displacements of the Subtropical Front following well-known NH cold events seem to decrease with progressing NH ice sheet deglaciation and parallel a weakening NH temperature response and amplitude of Intertropical Convergence Zone shifts. In addition, an exceptional poleward shift of Southern Hemisphere fronts occurs during the NH Heinrich Stadial 1. This event was likely facilitated by the NH ice maximum and acted as a coup-de-grâce for glacial ocean stratification and its high CO2 capacitance. Thus, through its influence on the global atmosphere and on ocean mixing, “excessive” NH glaciation could have triggered its own demise by facilitating the destratification of the glacial ocean CO2 state.

scholarly journals The Driving Mechanisms on Southern Ocean Upwelling Change during the Last Deglaciation

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 266
Author(s):  
Wei Liu ◽  
Zhengyu Liu ◽  
Shouwei Li
Keyword(s):  
Southern Ocean ◽  
Climate Model ◽  
Model Simulation ◽  
Early Stage ◽  
Surface Wind ◽  
Ekman Pumping ◽  
Last Deglaciation ◽  
Buoyancy Forcing ◽  
Local Topography ◽  
The Last Deglaciation

We explore the change in Southern Ocean upwelling during the last deglaciation, based on proxy records and a transient climate model simulation. Our analyses suggest that, beyond a conventional mechanism of the Southern Hemisphere westerlies shift, Southern Ocean upwelling is strongly influenced by surface buoyancy forcing and the local topography. Over the Antarctic Circumpolar Current region, the zonal mean and local upwelled flows exhibited distinct evolution patterns during the last deglaciation, since they are driven by different mechanisms. The zonal mean upwelling is primarily driven by surface wind stress via zonal mean Ekman pumping, whereas local upwelling is driven by both wind and buoyancy forcing, and is tightly coupled to local topography. During the early stage of the last deglaciation, the vertical extension of the upwelled flows increased downstream of submarine ridges but decreased upstream, which led to enhanced and diminished local upwelling, downstream and upstream of the submarine ridges, respectively.

Climate evolution at the last deglaciation: the role of the Southern Ocean

2004 ◽  
Vol 228 (3-4) ◽  
pp. 407-424 ◽  
Author(s):  
Cristina Bianchi ◽  
Rainer Gersonde
Keyword(s):  
Southern Ocean ◽  
Last Deglaciation ◽  
Climate Evolution ◽  
The Last Deglaciation

scholarly journals Regional carbon isotope syntheses from the last deglaciation

2017 ◽  
Vol 25 (3) ◽  
pp. 154-154
Author(s):  
Andreas Schmittner ◽  
G Martínez-Méndez ◽  
AC Mix ◽  
J Repschläger
Keyword(s):  
Carbon Isotope ◽  
Last Deglaciation ◽  
The Last Deglaciation

scholarly journals Rapid shifts in circulation and biogeochemistry of the Southern Ocean during deglacial carbon cycle events

2020 ◽  
Vol 6 (42) ◽  
pp. eabb3807
Author(s):  
Tao Li ◽  
Laura F. Robinson ◽  
Tianyu Chen ◽  
Xingchen T. Wang ◽  
Andrea Burke ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Deep Sea ◽  
Deep Ocean ◽  
Biological Pump ◽  
Last Deglaciation ◽  
Proxy Data ◽  
Ocean Ventilation ◽  
Carbon Release ◽  
The Last Deglaciation

The Southern Ocean plays a crucial role in regulating atmospheric CO2 on centennial to millennial time scales. However, observations of sufficient resolution to explore this have been lacking. Here, we report high-resolution, multiproxy records based on precisely dated deep-sea corals from the Southern Ocean. Paired deep (∆14C and δ11B) and surface (δ15N) proxy data point to enhanced upwelling coupled with reduced efficiency of the biological pump at 14.6 and 11.7 thousand years (ka) ago, which would have facilitated rapid carbon release to the atmosphere. Transient periods of unusually well-ventilated waters in the deep Southern Ocean occurred at 16.3 and 12.8 ka ago. Contemporaneous atmospheric carbon records indicate that these Southern Ocean ventilation events are also important in releasing respired carbon from the deep ocean to the atmosphere. Our results thus highlight two distinct modes of Southern Ocean circulation and biogeochemistry associated with centennial-scale atmospheric CO2 jumps during the last deglaciation.

An n-alkane and carbon isotope record during the last deglaciation from annually laminated sediment in Lake Xiaolongwan, northeastern China

2016 ◽  
Vol 56 (2-3) ◽  
pp. 189-203 ◽  
Author(s):  
Qing Sun ◽  
Manman Xie ◽  
Yuan Lin ◽  
Yabing Shan ◽  
Qingzeng Zhu ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Northeastern China ◽  
Last Deglaciation ◽  
Laminated Sediment ◽  
Annually Laminated Sediment ◽  
Isotope Record ◽  
The Last Deglaciation

scholarly journals Southern Ocean source of 14C-depleted carbon in the North Pacific Ocean during the last deglaciation

2010 ◽  
Vol 3 (11) ◽  
pp. 770-773 ◽  
Author(s):  
C. Basak ◽  
E. E. Martin ◽  
K. Horikawa ◽  
T. M. Marchitto
Keyword(s):  
Pacific Ocean ◽  
Southern Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Last Deglaciation ◽  
The North ◽  
The Last Deglaciation ◽  
The North Pacific
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