Timing of the descent into the last Ice Age determined by the bipolar seesaw

Barker, Stephen; Diz, Paula

doi:10.1002/2014pa002623

Cited by 78 publications

(116 citation statements)

References 129 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…The last millennial-scale increase in flow speeds at ∼17.5 ka coincides with Heinrich Stadial 1, the beginning of Southern Ocean upwelling and the end of the last ice age on a global scale (41). The reacceleration of sub-Antarctic DP transport matches the major deglacial warming in the sub-Antarctic Southeast Pacific and South Atlantic (42) (Fig. 4), suggesting a close coupling of DP throughflow to the initiation of Southern Hemisphere warming.…”

Section: Resultsmentioning

confidence: 65%

Glacial reduction and millennial-scale variations in Drake Passage throughflow

Lamy

Arz

Kilian

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

116

111

View full text Add to dashboard Cite

The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, crucial for advancing our understanding of the Southern Ocean’s role in global ocean and climate variability. Here, we reconstruct changes in DP throughflow dynamics over the past 65,000 y based on grain size and geochemical properties of sediment records from the southernmost continental margin of South America. Combined with published sediment records from the Scotia Sea, we argue for a considerable total reduction of DP transport and reveal an up to ∼40% decrease in flow speed along the northernmost ACC pathway entering the DP during glacial times. Superimposed on this long-term decrease are high-amplitude, millennial-scale variations, which parallel Southern Ocean and Antarctic temperature patterns. The glacial intervals of strong weakening of the ACC entering the DP imply an enhanced export of northern ACC surface and intermediate waters into the South Pacific Gyre and reduced Pacific–Atlantic exchange through the DP (“cold water route”). We conclude that changes in DP throughflow play a critical role for the global meridional overturning circulation and interbasin exchange in the Southern Ocean, most likely regulated by variations in the westerly wind field and changes in Antarctic sea ice extent.

show abstract

Section: Resultsmentioning

confidence: 65%

Glacial reduction and millennial-scale variations in Drake Passage throughflow

Lamy

Arz

Kilian

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

116

111

View full text Add to dashboard Cite

show abstract

“…Before proceeding, we want to reiterate that, whereas the age models for PS2498-1 and TN057-06 were adjusted by tuning to the EDC dust record, the age model for TN057-21 was tuned only by alignment with the oxygen isotope record of the North GRIP ice core [49]. Therefore, the correspondence of the palaeoproductivity record of TN057-21 (figure 6d,f ) with the records from the other cores (figures 5 and 6), as well as with the EDC dust record (figure 6a), supports the reliability of tuning the age models of PS2498-1 and TN057-06 to the EDC dust record.…”

Section: (B) Biological Response To Dustmentioning

confidence: 99%

Biological response to millennial variability of dust and nutrient supply in the Subantarctic South Atlantic Ocean

Anderson

Barker

Fleisher

et al. 2014

Phil. Trans. R. Soc. A.

Self Cite

112

View full text Add to dashboard Cite

Fluxes of lithogenic material and fluxes of three palaeo-productivity proxies (organic carbon, biogenic opal and alkenones) over the past 100 000 years were determined using the 230 Th-normalization method in three sediment cores from the Subantarctic South Atlantic Ocean. Features in the lithogenic flux record of each core correspond to similar features in the record of dust deposition in the EPICA Dome C ice core. Biogenic fluxes correlate with lithogenic fluxes in each sediment core. Our preferred interpretation is that South American dust, most probably from Patagonia, constitutes a major source of lithogenic material in Subantarctic South Atlantic sediments, and that past biological productivity in this region responded to variability in the supply of dust, probably due to biologically available iron carried by the dust. Greater nutrient supply as well as greater nutrient utilization (stimulated by dust) contributed to Subantarctic productivity during cold periods, in contrast to the region south of the Antarctic Polar Front (APF), where reduced nutrient supply during cold periods was the principal factor limiting productivity. The anti-phased patterns of productivity on opposite sides of the APF point to shifts in the physical supply of nutrients and to dust as cofactors regulating productivity in the Southern Ocean.

show abstract

“…The significant glacial decrease in Drake Passage transport, accompanied by a reduction of the ACC transport, strongly reduced the interbasin water mass exchange in the Southern Ocean and enhanced the high-low latitude exchange within the Pacific Eastern Boundary Current System ( Figure F6). The reacceleration of subantarctic Drake Passage transport matches the major deglacial warming in the subantarctic Southeast Pacific and South Atlantic (Barker and Diz, 2014), suggesting a close coupling of Drake Passage throughflow to the initiation of Southern Hemisphere warming.…”

Section: Hypothesis H1: Acc Dynamics and Drake Passage Throughflowmentioning

confidence: 68%