scholarly journals Links between eastern equatorial Pacific stratification and atmospheric CO 2 rise during the last deglaciation

2015 ◽  
Vol 30 (11) ◽  
pp. 1407-1424 ◽  
Author(s):  
Samantha C. Bova ◽  
Timothy Herbert ◽  
Yair Rosenthal ◽  
Julie Kalansky ◽  
Mark Altabet ◽  
...  
Keyword(s):  
Equatorial Pacific ◽  
Last Deglaciation ◽  
Eastern Equatorial Pacific ◽  
The Last Deglaciation

scholarly journals The Evolution of Deep Ocean Chemistry and Respired Carbon in the Eastern Equatorial Pacific Over the Last Deglaciation

2017 ◽  
Vol 32 (12) ◽  
pp. 1371-1385 ◽  
Author(s):  
Maria de la Fuente ◽  
Eva Calvo ◽  
Luke Skinner ◽  
Carles Pelejero ◽  
David Evans ◽  
...  
Keyword(s):  
Deep Ocean ◽  
Equatorial Pacific ◽  
Last Deglaciation ◽  
Eastern Equatorial Pacific ◽  
The Last Deglaciation ◽  
Ocean Chemistry

scholarly journals Increase in water column denitrification during the deglaciation controlled by oxygen demand in the eastern equatorial Pacific

2009 ◽  
Vol 6 (3) ◽  
pp. 5145-5161 ◽  
Author(s):  
P. Martinez ◽  
R. S. Robinson
Keyword(s):  
Water Column ◽  
Oxygen Demand ◽  
Deep Ocean ◽  
Leading Edge ◽  
Last Deglaciation ◽  
Equatorial Undercurrent ◽  
Export Production ◽  
Eastern Equatorial Pacific ◽  
The Last Deglaciation ◽  
Oxygen Minimum

Abstract. Here we present organic export production and isotopic nitrogen results over the last 30 000 years from one core localized off Costa Rica (ODP Site 1242) on the leading edge of the oxygen minimum zone of the Eastern Tropical North Pacific. Marine export production reveals glacial-interglacial variations with low organic matter (total organic carbon and total nitrogen) contents during warm intervals, twice more during cold episodes and double peaked maximum during the deglaciation, between ~15.5–18.5 and 11–13 ka BP. When this new export production record is compared with four nearby cores localized within the Eastern Pacific along the Equatorial divergence, a good agreement between all the cores is observed, with the major feature being a maximum of export during the early deglaciation. As for export production, water-column denitrification represented by sedimentary δ15N records along the Eastern tropical North and South Pacific between 15° N and 36° S is coherent as well over the last deglaciation period. The whole isotopic nitrogen profiles indicate that denitrification increased abruptly at 19 ka BP to a maximum during the early deglaciation, confirming a typical Antarctic timing. It is proposed that the increase in export production and then in subsurface oxygen demand lead to an intensification of water-column denitrification within the oxygen minimum zones in the easternmost Pacific at the time of the last deglaciation. The triggering mechanism would have been primarily linked to an increase in preformed nutrients contents feeding the Equatorial Undercurrent driven by the resumption of overturning in the Southern Ocean and the return of nutrients from the deep ocean to the sea-surface. An increase in equatorial wind-driven upwelling of sub-surface nutrient-rich waters could have played the role of an amplifier.

scholarly journals The Atmospheric Bridge Communicated the δ<sup>13</sup>C Decline during the Last Deglaciation to the Global Upper Ocean

2020 ◽  
Author(s):  
Jun Shao ◽  
Lowell D Stott ◽  
Laurie Menviel ◽  
Andy Ridgwell ◽  
Malin Ödalen ◽  
...  
Keyword(s):  
Nutrient Transport ◽  
Deep Ocean ◽  
Upper Ocean ◽  
Last Deglaciation ◽  
Planktic Foraminifera ◽  
Proxy Records ◽  
Deep Waters ◽  
Eastern Equatorial Pacific ◽  
The Last Deglaciation ◽  
Atmospheric Pco2

Abstract. During the early last glacial termination (17.2–15 ka) atmospheric δ13C declined sharply by 0.3–0.4 ‰ as atmospheric pCO2 rose. This was the initial part of the atmospheric δ13C excursion that lasted for multiple thousand years. A similar δ13C decline has been documented in marine proxy records from both surface and thermocline-dwelling planktic foraminifera. The foraminiferal δ13C decline has previously been attributed to a flux of respired carbon from the deep ocean that was subsequently transported within the upper ocean (i.e. bottom up transport) to sites where the signal is recorded. Here, we provide modeling evidence that when respired carbon upwells in the Southern Ocean, negative δ13C anomalies in the global upper ocean were instead transferred from the atmosphere (i.e. top down transport). Due to this efficient atmospheric bridge, the pathway of δ13C transport was likely to be different from nutrient transport during the early deglaciation. This implies that the usage of planktic δ13C records for identifying the carbon source(s) responsible for the atmospheric pCO2 rise during the early deglaciation is limited. The model results also suggest that thermocline waters in upwelling systems like the eastern equatorial Pacific, and even upper deep waters above 2000 m, can be affected by this atmospheric bridge during the early deglaciation. Our results imply that caution must be applied when interpreting early deglacial marine δ13C records from depths that are potentially affected by the atmosphere.

scholarly journals Equatorial Pacific seawater pCO2 variability since the last glacial period

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kaoru Kubota ◽  
Yusuke Yokoyama ◽  
Tsuyoshi Ishikawa ◽  
Takuya Sagawa ◽  
Minoru Ikehara ◽  
...  
Keyword(s):  
Isotope Analysis ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Last Deglaciation ◽  
Last Glacial Period ◽  
Near Surface ◽  
Surface Dwelling ◽  
The Last Deglaciation ◽  
Global Carbon ◽  
The Last Glacial

Abstract The ocean may have played a central role in the atmospheric pCO2 rise during the last deglaciation. However, evidence on where carbon was exchanged between the ocean and the atmosphere in this period is still lacking, hampering our understanding of global carbon cycle on glacial–interglacial timescales. Here we report a new surface seawater pCO2 reconstruction for the western equatorial Pacific Ocean based on boron isotope analysis—a seawater pCO2 proxy—using two species of near-surface dwelling foraminifera from the same marine sediment core. The results indicate that the region remained a modest CO2 sink throughout the last deglaciation.

scholarly journals Larger CO2 source at the equatorial Pacific during the last deglaciation

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Kaoru Kubota ◽  
Yusuke Yokoyama ◽  
Tsuyoshi Ishikawa ◽  
Stephen Obrochta ◽  
Atsushi Suzuki
Keyword(s):  
Equatorial Pacific ◽  
Last Deglaciation ◽  
The Last Deglaciation
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