Glacial deep ocean sequestration of CO2 driven by the eastern equatorial Pacific biologic pump

Doss, Whitney; Marchitto, Thomas M.

doi:10.1016/j.epsl.2013.07.019

Cited by 22 publications

(30 citation statements)

References 121 publications

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“…The [CO 3 2− ] and δ 13 C results presented here from ODP1240 are in good agreement with these expectations (Figures d and e), as well as with a previous study in the area (Doss & Marchitto, ), showing lower δ 13 C and [CO 3 2− ] during the late glacial, in parallel with reduced radiocarbon ventilation, and an increase in all of these parameters across the deglaciation. Interestingly, when the modern [CO 3 2− ] value from this area is taken into account, a drop at the late Holocene is inferred.…”

Section: Discussionsupporting

confidence: 92%

“…A different interpretation based on similar glacial‐interglacial Δ[CO 3 2− ] changes, also from the Panama Basin, has been proposed by Doss and Marchitto (). This study suggests that the observed glacial Δ[CO 3 2− ] difference found between a sediment core located at the sill depth and sediment cores located deeper in the basin are indicative of an increase in the export production during the last glacial.…”

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 90%

“…Interestingly, calculations based on the modern δ 13 C‐[CO 3 2− ] relationship in the Panama Basin suggest that the observed glacial‐interglacial δ 13 C difference is compatible with the observed glacial‐interglacial offset in [CO 3 2− ] (when a whole ocean glacial‐interglacial δ 13 C change of ~0.3‰ is assumed, due to terrestrial carbon release), which would imply no further [CO 3 2− ] addition from calcite dissolution (Doss & Marchitto, ). Following the calculations of Doss and Marchitto (), a 10 μmol/kg [CO 3 2− ] glacial‐interglacial drop would achieve a 30 μmol/kg DIC increase, which in turn would produce a ~0.26‰ change in δ 13 C due to respired carbon addition. If a whole ocean change of ~0.3‰ (Peterson et al, ) is assumed to have occurred exclusively due to terrestrial carbon release (Shackleton, ), a total change of ~0.56‰ would therefore be expected, which is not very far off the results of Doss and Marchitto () and our observed glacial‐interglacial δ 13 C difference of 0.4 ± 0.06‰.…”

Section: Discussionmentioning

confidence: 90%

“…Deep water [CO 3 2− ] offset between LGM (~18–23 kyr) and Holocene/modern (~0–8 kyr) from several Atlantic/Southern Ocean (in blue) and Indo‐Pacific Ocean (in orange) sediment cores. DSDP593Z (Elmore et al, ); RR0503‐83 (Allen et al, ); MW91‐9 GGC15, MW91‐9 GGC48, WIND 28K, and VM28‐122 (Yu et al, ); TTNO13 PC61 (Yu et al, ); BOFS and NEAP cores (Yu et al, ; Yu & Elderfield, ); RC13‐140, RC23‐22, and RC23‐15 (Doss & Marchitto, ); RC16‐59 (Broecker et al, ); GeoB cores (Raitzsch et al, ); MD07‐3076 (Gottschalk et al, ); TN057‐21 (Yu, Anderson, Jin, et al, ); and ODP1240 (this study, highlighted in bold). WP: western Pacific; EEP: Eastern Equatorial Pacific; CP: central Pacific; NEA: North East Atlantic; WEA: western equatorial Pacific; EqA: equatorial Atlantic; SO: Southern Ocean; IO: Indian Ocean.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2017

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It has been shown that the deep Eastern Equatorial Pacific (EEP) region was poorly ventilated during the Last Glacial Maximum (LGM) relative to Holocene values. This finding suggests a more efficient biological pump, which indirectly supports the idea of increased carbon storage in the deep ocean contributing to lower atmospheric CO2 during the last glacial. However, proxies related to respired carbon are needed in order to directly test this proposition. Here we present Cibicides wuellerstorfi B/Ca ratios from Ocean Drilling Program Site 1240 measured by laser ablation inductively coupled plasma mass spectrometry (LA‐ICPMS) as a proxy for deep water carbonate saturation state (Δ[CO32−], and therefore [CO32−]), along with δ13C measurements. In addition, the U/Ca ratio in foraminiferal coatings has been analyzed as an indicator of oxygenation changes. Our results show lower [CO32−], δ13C, and [O2] values during the LGM, which would be consistent with higher respired carbon levels in the deep EEP driven, at least in part, by reduced deep water ventilation. However, the difference between LGM and Holocene [CO32−] observed at our site is relatively small, in accordance with other records from across the Pacific, suggesting that a “counteracting” mechanism, such as seafloor carbonate dissolution, also played a role. If so, this mechanism would have increased average ocean alkalinity, allowing even more atmospheric CO2 to be “sequestered” by the ocean. Therefore, the deep Pacific Ocean very likely stored a significant amount of atmospheric CO2 during the LGM, specifically due to a more efficient biological carbon pump and also an increase in average ocean alkalinity.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

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

et al. 2017

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Middle Eocene to Late Oligocene Antarctic glaciation/deglaciation and Southern Ocean productivity

et al. 2014

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During the Eocene-Oligocene transition, Earth cooled significantly from a greenhouse to an icehouse climate. Nannofossil assemblages from Southern Ocean sites enable evaluation of paleoceanographic changes and, hence, of the oceanic response to Antarctic ice sheet evolution during the Eocene and Oligocene. A combination of environmental factors such as sea surface temperature and nutrient availability is recorded by the nannofossil assemblages of and can be interpreted as responses to the following changes. A cooling trend, started in the Middle Eocene, was interrupted by warming during the Middle Eocene Climatic optimum and by short cooling episodes. The cooling episode at 39.6 Ma preceded a shift toward an interval that was dominated by oligotrophic nannofossil assemblages from~39.1 to~36.2 Ma. We suggest that oligotrophic conditions were associated with increased water mass stratification, low nutrient contents, and high efficiency of the oceanic biological pump that, in turn, promoted sequestration of carbon from surface waters, which favored cooling. After 36.2 Ma, we document a large synchronous surface water productivity turnover with a dominant eutrophic nannofossil assemblage that was accompanied by a pronounced increase in magnetotactic bacterial abundance. This turnover reflects a response of coccolithophorids to changed nutrient inputs that was likely related to partial deglaciation of a transient Antarctic ice sheet and/or to iron delivery to the sea surface. Eutrophic conditions were maintained throughout the Oligocene, which was characterized by a nannofossil assemblage shift toward cool conditions at the Eocene-Oligocene transition. Finally, a warm nannofossil assemblage in the Late Oligocene indicates a warming phase.

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Radiocarbon dating of planktonic foraminifer shells: A cautionary tale

Mekik

2014

Paleoceanography

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[1] Sedimentation rate, bioturbation, winnowing, and calcite dissolution produce significant radiocarbon age offsets among multiple species of coexisting planktonic foraminifers and pteropod fragments. We compare the radiocarbon age of foraminifer species and pteropod fragments with estimates of percent calcite dissolved made with a sedimentary proxy (Globorotalia menardii fragmentation index-MFI) to delineate the effect of dissolution on radiocarbon age of foraminifers. Data from two core top transects on the Rio Grande Rise (RIO) and Ontong Java Plateau (OJP) and from down core sediments of varying sedimentation rates in the tropical Pacific (ME-27, MD98 2177, and MW91-9 56GGC) reveal that sediments with the greatest accumulation rates produce the least age offsets among coexisting species. Age offsets among coexisting foraminifers are about 3500 years on RIO, and 1000 years on OJP. Two core tops from RIO yield an age of the Last Glacial Maximum possibly due to mass displacement of younger sediments downslope. Foraminifer age increases with increasing dissolution and there is a consistent pattern of older foraminifer fragments coexisting with younger whole shells of the same species. The only exception is sediments which have experienced high dissolution where fragments are younger than whole shells. The age offset between fragments of G. menardii and its coexisting whole shells does not exceed the age offset among other coexisting foraminifer species in the same core tops.

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Glacial deep ocean sequestration of CO2 driven by the eastern equatorial Pacific biologic pump

Cited by 22 publications

References 121 publications

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

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

Middle Eocene to Late Oligocene Antarctic glaciation/deglaciation and Southern Ocean productivity

Radiocarbon dating of planktonic foraminifer shells: A cautionary tale

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