On the sensitivity of ocean circulation to arctic freshwater input during the Paleocene/Eocene Thermal Maximum

2011 ◽  
Vol 306 (1-2) ◽  
pp. 82-94 ◽  
Author(s):  
Jesse T. Cope ◽  
Arne Winguth
Keyword(s):  
Ocean Circulation ◽  
Freshwater Input ◽  
Thermal Maximum

scholarly journals Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jussi Hovikoski ◽  
Michael B. W. Fyhn ◽  
Henrik Nøhr-Hansen ◽  
John R. Hopper ◽  
Steven Andrews ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
High Latitude ◽  
Seismic Reflection ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Early Eocene ◽  
Subaerial Exposure ◽  
Thermal Maximum ◽  
Volcanic Facies

AbstractThe paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins. We identify Paleocene–Eocene uplift that culminated in widespread regression, volcanism, and subaerial exposure during the Ypresian. We reconstruct the paleogeography of the northeast Atlantic–Arctic region and propose that this uplift led to fragmentation of the Norwegian–Greenland seaway during this period. We suggest that the seaway became severely restricted between about 56 and 53 million years ago, effectively isolating the Arctic from the Atlantic ocean during the Paleocene–Eocene thermal maximum and the early Eocene.

scholarly journals Freshening of Antarctic Intermediate Water in the South Atlantic Ocean in 2005–2014

2016 ◽  
Author(s):  
Wenjun Yao ◽  
Jiuxin Shi
Keyword(s):  
Atlantic Ocean ◽  
Ocean Circulation ◽  
Hydrological Cycle ◽  
World Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Intermediate Water ◽  
Freshwater Input ◽  
The South ◽  
Antarctic Intermediate Water

Abstract. Basin-scaled freshening of Antarctic Intermediate Water (AAIW) is reported to have dominated South Atlantic Ocean during period from 2005 to 2014, as shown by the gridded monthly means Argo (Array for Real-time Geostrophic Oceanography) data. The relevant investigation was also revealed by two transatlantic occupations of repeated section along 30° S, from World Ocean Circulation Experiment Hydrographic Program. Freshening of the AAIW was compensated by the opposing salinity increase of thermocline water, indicating the contemporaneous hydrological cycle intensification. This was illustrated by the precipitation less evaporation change in the Southern Hemisphere from 2000 to 2014, with freshwater input from atmosphere to ocean surface increasing in the subpolar high-precipitation region and vice versa in the subtropical high-evaporation region. Against the background of hydrological cycle augment, the decreased transport of Agulhas Leakage (AL) was proposed to be one of the contributors for the associated freshening of AAIW. This indirectly estimated variability of AL, reflected by the weakening of wind stress over the South Indian Ocean since the beginning of 2000s, facilitates the freshwater input from source region and partly contributes to the observed freshened AAIW. Both of our mechanical analysis is qualitative, but this work would be helpful to validate and test predictably coupled sea-air model simulations.

CO2-driven ocean circulation changes as an amplifier of Paleocene-Eocene thermal maximum hydrate destabilization

Geology ◽  
2010 ◽  
Vol 38 (10) ◽  
pp. 875-878 ◽  
Author(s):  
Daniel J. Lunt ◽  
Paul J. Valdes ◽  
Tom Dunkley Jones ◽  
Andy Ridgwell ◽  
Alan M. Haywood ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Thermal Maximum ◽  
Circulation Changes

The Carbon Cycle

2019 ◽  
pp. 129-158
Author(s):  
Han Dolman
Keyword(s):  
Carbon Cycle ◽  
Primary Production ◽  
Ocean Circulation ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Carbon Stocks ◽  
Climate Feedback ◽  
Fossil Fuel Burning ◽  
Thermal Maximum ◽  
Natural Carbon

The chapter first shows carbon dioxide variability over long geological timescales. The current stocks and fluxes of carbon are then given, for the whole planet and for the atmosphere, ocean and land separately. The main flows of carbon in the ocean, through the biological pump (via uptake through photosynthesis) and the physical pump (via involving chemical transformation uptake in water and production of carbonate), and on land, through photosynthesis (Gross Primary Production) and respiration leading to Net Primary Production, Net Ecosystem Production and Net Biome Production and through the storage of carbon in biomass, are described. Next, carbon interactions during the Paleocene–Eocene Thermal Maximum and glacial–interglacial transitions, thought to involve changes in ocean circulation and upwelling, are examined. The key changes from anthropogenic perturbation of the natural carbon cycle are shown to be due to fossil fuel burning and land-use change (deforestation). The effects of the carbon–climate feedback on temperature and carbon stocks are also shown.

scholarly journals Changes in benthic ecosystems and ocean circulation in the Southeast Atlantic across Eocene Thermal Maximum 2

2015 ◽  
Vol 30 (8) ◽  
pp. 1059-1077 ◽  
Author(s):  
S. M. Jennions ◽  
E. Thomas ◽  
D. N. Schmidt ◽  
D. Lunt ◽  
A. Ridgwell
Keyword(s):  
Ocean Circulation ◽  
Thermal Maximum ◽  
Benthic Ecosystems

scholarly journals Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes

2016 ◽  
Vol 12 (4) ◽  
pp. 837-847 ◽  
Author(s):  
April N. Abbott ◽  
Brian A. Haley ◽  
Aradhna K. Tripati ◽  
Martin Frank
Keyword(s):  
Ocean Circulation ◽  
Deep Water ◽  
Deep Ocean ◽  
Isotopic Data ◽  
Carbon Isotopic ◽  
Deep Waters ◽  
Atmosphere System ◽  
Thermal Maximum ◽  
Ocean Atmosphere ◽  
Deep Ocean Circulation

Abstract. Global warming during the Paleocene–Eocene Thermal Maximum (PETM)  ∼  55 million years ago (Ma) coincided with a massive release of carbon to the ocean–atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role of changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites to reconstruct past deep-ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth Nd isotopes and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for initiation and recovery of the ocean–atmosphere system associated with the PETM.

scholarly journals Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes

2015 ◽  
Vol 11 (3) ◽  
pp. 2557-2583 ◽  
Author(s):  
A. N. Abbott ◽  
B. A. Haley ◽  
A. K. Tripati ◽  
M. Frank
Keyword(s):  
Ocean Circulation ◽  
Deep Water ◽  
Deep Ocean ◽  
Published Data ◽  
Isotopic Data ◽  
Carbon Isotopic ◽  
Atmosphere System ◽  
Thermal Maximum ◽  
Ocean Atmosphere ◽  
Deep Ocean Circulation

Abstract. Global warming during the Paleocene Eocene Thermal Maximum (PETM) ~55 million years ago (Ma) coincided with a massive release of carbon to the ocean–atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role for changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites and comparing data with published data from fossil fish debris to reconstruct past deep ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for global recovery of the ocean–atmosphere system after the PETM.

scholarly journals The Paleocene–Eocene Thermal Maximum at DSDP Site 277, Campbell Plateau, southern Pacific Ocean

2015 ◽  
Vol 11 (7) ◽  
pp. 1009-1025 ◽  
Author(s):  
C. J. Hollis ◽  
B. R. Hines ◽  
K. Littler ◽  
V. Villasante-Marcos ◽  
D. K. Kulhanek ◽  
...  
Keyword(s):  
Surface Water ◽  
Ocean Circulation ◽  
Surface Waters ◽  
Sediment Cores ◽  
Warm Season ◽  
Diagenetic Alteration ◽  
Thermal Maximum ◽  
Southern Pacific Ocean ◽  
Water Values ◽  
Dsdp Site

Abstract. Re-examination of sediment cores from Deep Sea Drilling Project (DSDP) Site 277 on the western margin of the Campbell Plateau (paleolatitude of ~65° S) has identified an intact Paleocene–Eocene (P–E) boundary overlain by a 34 cm thick record of the Paleocene–Eocene Thermal Maximum (PETM) within nannofossil chalk. The upper part of the PETM is truncated, either due to drilling disturbance or a sedimentary hiatus. An intact record of the onset of the PETM is indicated by a gradual decrease in δ13C values over 20 cm, followed by a 14 cm interval in which δ13C is 2 ‰ lighter than uppermost Paleocene values. After accounting for effects of diagenetic alteration, we use δ18O and Mg/Ca values from foraminiferal tests to determine that intermediate and surface waters warmed by ~5–6° at the onset of the PETM prior to the full development of the negative δ13C excursion. After this initial warming, sea temperatures were relatively stable through the PETM but declined abruptly across the horizon that truncates the event at this site. Mg/Ca analysis of foraminiferal tests indicates peak intermediate and surface water temperatures of ~19 and ~32 °C, respectively. These temperatures may be influenced by residual diagenetic factors and changes in ocean circulation, and surface water values may also be biased towards warm-season temperatures.

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