Journal ArticleDOI
Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation
J.-C. Duplessy,N.J. Shackleton,Richard G. Fairbanks,Laurent Labeyrie,Delia W Oppo,Nejib Kallel +5 more
TLDR
In this paper, a detailed reconstruction of the geographic distribution of ∂13C in benthic foraminifera in the Atlantic Ocean during the last glacial maximum was presented.Abstract:
The degree of similarity of the ∂13C records of the planktonic foraminiferal species N. pachyderma and of the benthic foraminiferal genus Cibicides in the high-latitude basins of the world ocean is used as an indicator of the presence of deepwater sources during the last climatic cycle. Whereas continuous formation of deep water is recognized in the southern ocean, the Norwegian Sea stopped acting as a sink for surface water during isotope stage 4 and the remainder of the last glaciation. However, deep water formed in the north Atlantic south of the Norwegian Sea during the last climatic cycle as early as isotope substage 5d, and this area was also the only active northern source during stages 4–2. A detailed reconstruction of the geographic distribution of ∂13C in benthic foraminifera in the Atlantic Ocean during the last glacial maximum shows that the most important deepwater mass originated from the southern ocean, whereas the Glacial North Atlantic Deep Water cannot be traced south of 40°N. At shallower depth an oxygenated 13C rich Intermediate Water mass extended from 45°N to 15°S. In the Pacific Ocean a ventilation higher than the modern one was also found in open ocean in the depth range 700–2600 m and is best explained by stronger formation of Intermediate Water in high northern latitudes.read more
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Journal ArticleDOI
Sea-level and deep water temperature changes derived from benthic foraminifera isotopic records
Claire Waelbroeck,Laurent Labeyrie,Laurent Labeyrie,Elisabeth Michel,Jean-Claude Duplessy,Jerry F. McManus,Kurt Lambeck,Estelle Balbon,Monique Labracherie +8 more
TL;DR: In this paper, robust regressions were established between relative sea-level (RSL) data and benthic foraminifera oxygen isotopic ratios from the North Atlantic and Equatorial Pacific Ocean over the last climatic cycle.
Journal ArticleDOI
Glacial/interglacial variations in atmospheric carbon dioxide
Daniel M. Sigman,Edward A. Boyle +1 more
TL;DR: A version of the hypothesis that the whole-ocean reservoir of algal nutrients was larger during glacial times, strengthening the biological pump at low latitudes, where these nutrients are currently limiting is presented.
Journal ArticleDOI
Abrupt climate change
Richard B. Alley,Jochem Marotzke,William D. Nordhaus,Jonathan T. Overpeck,Dorothy M. Peteet,Roger A. Pielke,Raymond T. Pierrehumbert,Peter B. Rhines,Thomas F. Stocker,Lynne D. Talley,John M. Wallace +10 more
TL;DR: Policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies.
Journal ArticleDOI
On the Structure and Origin of Major Glaciation Cycles 1. Linear Responses to Milankovitch Forcing
John Imbrie,Edward A. Boyle,Steven C. Clemens,A. Duffy,William R Howard,George Kukla,John E. Kutzbach,Douglas G. Martinson,Andrew McIntyre,Alan C. Mix,B. Molfino,Joseph J. Morley,Larry C. Peterson,Nicklas G Pisias,Warren L. Prell,Maureen E. Raymo,N.J. Shackleton,J. R. Toggweiler +17 more
TL;DR: Starr et al. as mentioned in this paper showed that the 23,000 and 41,000-year cycles of glaciation are continuous, linear responses to orbitally driven changes in the Arctic radiation budget, and used the phase progression in each climatic cycle to identify the main pathways along which the initial, local responses to radiation are propagated by the atmosphere and ocean.
Journal ArticleDOI
The role of ocean-atmosphere reorganizations in glacial cycles
TL;DR: In this paper, a case is made that glacial-to-interglacial transitions involve major reorganizations of the ocean-atmosphere system, and that these reorganizations constitute jumps between stable modes of operation which cause changes in the greenhouse gas content and albedo of the atmosphere.
References
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Journal ArticleDOI
Global variations of surface ocean productivity in low and mid latitudes: Influence on CO2 reservoirs of the deep ocean and atmosphere during the last 21,000 years
TL;DR: Based on detailed reconstructions of global distribution patterns, both paleoproductivity and the benthic δ13C record of CO2, which is dissolved in the deep ocean, strongly differed between the Last Glacial Maximum and the Holocene.
Journal ArticleDOI
Variations in mode of formation and temperature of oceanic deep waters over the past 125,000 years
TL;DR: In this paper, a detailed comparison of the oxygen isotopic composition of benthicforaminiferafrom sediment cores taken from the Norwegian Sea, and the Pacific, Atlantic and Southern oceans is revealed.
Journal ArticleDOI
Deep Circulation of the North Atlantic over the Last 200,000 Years: Geochemical Evidence
Edward A. Boyle,Lloyd D Keigwin +1 more
TL;DR: Data from a North Atlantic sediment core show that over the past 200,000 years there has been a continuous supply of nutrient-depleted waters into the deep North Atlantic, and indicates that the continental carbon inventory may have been less variable than previously suggested.
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North Atlantic thermohaline circulation during the past 20,000 years linked to high-latitude surface temperature
Edward A. Boyle,Lloyd D Keigwin +1 more