scholarly journals Deconvolving Glacial Ocean Carbonate Chemistry from the Planktonic Foraminifera Carbon Isotope Record

1999 ◽  
pp. 329-342 ◽  
Author(s):  
Howard J. Spero ◽  
Jelle Bijma ◽  
David W. Lea ◽  
Ann D. Russell
Keyword(s):  
Carbon Isotope ◽  
Planktonic Foraminifera ◽  
Carbonate Chemistry ◽  
Isotope Record

scholarly journals Capturing the global signature of surface ocean acidification during the Palaeocene–Eocene Thermal Maximum

2018 ◽  
Vol 376 (2130) ◽  
pp. 20170072 ◽  
Author(s):  
Tali L. Babila ◽  
Donald E. Penman ◽  
Bärbel Hönisch ◽  
D. Clay Kelly ◽  
Timothy J. Bralower ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Carbon Isotope ◽  
Atmospheric Carbon Dioxide ◽  
Environmental Changes ◽  
Planktonic Foraminifera ◽  
Tight Coupling ◽  
Carbonate Chemistry ◽  
Surface Ocean ◽  
Thermal Maximum ◽  
Carbon Release

Geologically abrupt carbon perturbations such as the Palaeocene–Eocene Thermal Maximum (PETM, approx. 56 Ma) are the closest geological points of comparison to current anthropogenic carbon emissions. Associated with the rapid carbon release during this event are profound environmental changes in the oceans including warming, deoxygenation and acidification. To evaluate the global extent of surface ocean acidification during the PETM, we present a compilation of new and published surface ocean carbonate chemistry and pH reconstructions from various palaeoceanographic settings. We use boron to calcium ratios (B/Ca) and boron isotopes (δ 11 B) in surface- and thermocline-dwelling planktonic foraminifera to reconstruct ocean carbonate chemistry and pH. Our records exhibit a B/Ca reduction of 30–40% and a δ 11 B decline of 1.0–1.2‰ coeval with the carbon isotope excursion. The tight coupling between boron proxies and carbon isotope records is consistent with the interpretation that oceanic absorption of the carbon released at the onset of the PETM resulted in widespread surface ocean acidification. The remarkable similarity among records from different ocean regions suggests that the degree of ocean carbonate change was globally near uniform. We attribute the global extent of surface ocean acidification to elevated atmospheric carbon dioxide levels during the main phase of the PETM. This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.

The South Atlantic Carbon Isotope Record of Planktic Foraminifera

1999 ◽  
pp. 427-445 ◽  
Author(s):  
S. Mulitza ◽  
H. Arz ◽  
S. Kemle-von Mücke ◽  
C. Moos ◽  
H.-S. Niebler ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
South Atlantic ◽  
The South ◽  
Planktic Foraminifera ◽  
Isotope Record

The Tertiary Carbon Isotope Record

1988 ◽  
pp. 51-54
Author(s):  
DOUGLAS F. WILLIAMS ◽  
IAN LERCHE ◽  
W.E. FULL
Keyword(s):  
Carbon Isotope ◽  
Tertiary Carbon ◽  
Isotope Record

scholarly journals Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic

2015 ◽  
Vol 11 (4) ◽  
pp. 669-685 ◽  
Author(s):  
C. Consolaro ◽  
T. L. Rasmussen ◽  
G. Panieri ◽  
J. Mienert ◽  
S. Bünz ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbon Isotope ◽  
Deep Water ◽  
Planktonic Foraminifera ◽  
Sediment Supply ◽  
The Arctic ◽  
Fram Strait ◽  
The North ◽  
Carbon Isotope Excursion

Abstract. We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dates reveal a detailed chronology for the last 14 ka BP. The δ 13C record measured on the benthonic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values termed carbon isotope excursion (CIE I and CIE II, respectively). The values were as low as −4.37‰ in CIE I, correlating with the Bølling–Allerød interstadials, and as low as −3.41‰ in CIE II, correlating with the early Holocene. In the Bølling–Allerød interstadials, the planktonic foraminifera also show negative values, probably indicating secondary methane-derived authigenic precipitation affecting the foraminiferal shells. After a cleaning procedure designed to remove authigenic carbonate coatings on benthonic foraminiferal tests from this event, the 13C values are still negative (as low as −2.75‰). The CIE I and CIE II occurred during periods of ocean warming, sea-level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic, suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

Are Late Permian carbon isotope excursions of local or of global significance?

2019 ◽  
Vol 132 (3-4) ◽  
pp. 521-544 ◽  
Author(s):  
Borhan Bagherpour ◽  
Hugo Bucher ◽  
Torsten Vennemann ◽  
Elke Schneebeli-Hermann ◽  
Dong-xun Yuan ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
South China ◽  
Sea Water ◽  
Equatorial Position ◽  
Late Permian ◽  
Terrestrial Organic Matter ◽  
Triassic Boundary ◽  
Atmospheric Propagation ◽  
Isotope Record ◽  
Permian Triassic Boundary

Abstract We present a new, biostratigraphically calibrated organic and inorganic C-isotope record spanning the basal Late Permian to earliest Triassic from southern Guizhou (Nanpanjiang basin, South China). After fluctuations of a likely diagenetic overprint are removed, three negative carbon isotope excursions (CIEs) persist. These include a short-lived CIE during the early Wuchiapingian, a protracted CIE ending shortly after the Wuchiapingian–Changhsingian Boundary, and a third CIE straddling the Permian–Triassic boundary. Comparison of our new C-isotope record with others from the same basin suggests that influences of local bathymetry and of the amount of buried terrestrial organic matter are of importance. Comparison with other coeval time series outside of South China also highlights that only the negative CIE at the Permian–Triassic boundary is a global signal. These differences can be explained by the different volumes of erupted basalts between the Late Permian Emeishan and the younger Siberian large igneous provinces and their distinct eruptive modalities. Emeishan volcanism was largely submarine, implying that sea water was an efficient buffer against atmospheric propagation of volatiles. The equatorial position of Emeishan was also an additional obstacle for volatiles to reach the stratosphere and benefit from an efficient global distribution. Consequently, the local significance of these CIEs calls into question global correlations based on C-isotope chemostratigraphy during the Late Permian. The timing of the Late Permian Chinese CIEs is also not reflected in changes in species diversity or ecology, unlike the sudden and global Permian–Triassic boundary crisis and subsequent Early Triassic upheavals.

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