Preferential dissolution of benthic foraminiferal calcite during laboratory reductive cleaning

Yu, Jimin; Elderfield, Henry; Greaves, Mervyn; Day, Jason

doi:10.1029/2006gc001571

Cited by 87 publications

(95 citation statements)

References 46 publications

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“…CO 2 uncertainty into our estimates of atmospheric CO 2 using δ 11 B. Splits for elemental and δ 11 B analyses were cleaned following established methods [38][39][40] . Trace-element ratios were determined as in ref.…”

Section: Site Informationmentioning

confidence: 99%

Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate

Anagnostou

John

Edgar

et al. 2016

Nature

392

377

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The Early Eocene Climate Optimum (EECO, which occurred about 51 to 53 million years ago) 1 , was the warmest interval of the past 65 million years, with mean annual surface air temperature over ten degrees Celsius warmer than during the pre-industrial period 2-4 . Subsequent global cooling in the middle and late Eocene epoch, especially at high latitudes, eventually led to continental ice sheet development in Antarctica in the early Oligocene epoch (about 33.6 million years ago). However, existing estimates place atmospheric carbon dioxide (CO 2 ) levels during the Eocene at 500-3,000 parts per million [5][6][7] , and in the absence of tighter constraints carbon-climate interactions over this interval remain uncertain. Here we use recent analytical and methodological developments 8-11 to generate a new high-fidelity record of CO 2 concentrations using the boron isotope (δ 11 Β) composition of well preserved planktonic foraminifera from the Tanzania Drilling Project, revising previous estimates 6 . Although species-level uncertainties make absolute values difficult to constrain, CO 2 concentrations during the EECO were around 1,400 parts per million. The relative decline in DOI: 10.1038/nature17423 Page 2 of 38 CO 2 concentration through the Eocene is more robustly constrained at about fifty per cent, with a further decline into the Oligocene 12 . Provided the latitudinal dependency of sea surface temperature change for a given climate forcing in the Eocene was similar to that of the late Quaternary period 13 , this CO 2 decline was sufficient to drive the well documented high-and low-latitude cooling that occurred through the Eocene 14 . Once the change in global temperature between the pre-industrial period and the Eocene caused by the action of all known slow feedbacks (apart from those associated with the carbon cycle) is removed 2-4 , both the EECO and the late Eocene exhibit an equilibrium climate sensitivity relative to the pre-industrial period of 2.1 to 4.6 degrees Celsius per CO 2 doubling (66 per cent confidence), which is similar to the canonical range (1.5 to 4.5 degrees Celsius 15 ), indicating that a large fraction of the warmth of the early Eocene greenhouse was driven by increased CO 2 concentrations, and that climate sensitivity was relatively constant throughout this period.Over the past 540 million years, Earth's climate has oscillated between a globally warm 'greenhouse state' and an 'icehouse state' with substantial continental glaciation 16 . The most recent of these transitions occurred between the warmest time interval of the last 65 million years-the EECO (about 14 ± 3 °C warmer than preindustrial times 2 )-and the rapid growth of ice on Antarctica in the earliest icehouse state of the Oligocene (~33.6 Myr ago 1 ). It has been suggested that variations in the concentration of the greenhouse gas CO 2 were responsible for both the overall warmth of the Eocene and the subsequent cooling 17 . Recent studies have documented the importance of CO 2 decline for the final step into the icehous...

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Section: Site Informationmentioning

confidence: 99%

Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate

Anagnostou

John

Edgar

et al. 2016

Nature

392

377

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“…Original Mg/Ca values we obtained for each record and we calculated SST for each data set using the thermometer of Anand et al 40 Mg/Ca values of the records that employed reductive cleaning protocol during sample preparation were also corrected by a 15% decrease in Mg/Ca due to foraminiferal dissolution reported by Barker et al 28 and Yu et al 41 A summary of all SST records used for the Equatorial Pacific is presented in Supplementary Fig. S3 and shows reasonable consistency between these records.…”

Section: Methodsmentioning

confidence: 99%

Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state

et al. 2013

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The El Niño-Southern Oscillation (ENSO) is one of the most important components of the global climate system, but its potential response to an anthropogenic increase in atmospheric CO 2 remains largely unknown. One of the major limitations in ENSO prediction is our poor understanding of the relationship between ENSO variability and long-term changes in Tropical Pacific oceanography. Here we investigate this relationship using palaeorecords derived from the geochemistry of planktonic foraminifera. Our results indicate a strong negative correlation between ENSO variability and zonal gradient of sea-surface temperatures across the Tropical Pacific during the last 22 ky. This strong correlation implies a mechanistic link that tightly couples zonal sea-surface temperature gradient and ENSO variability during large climate changes and provides a unique insight into potential ENSO evolution in the future by suggesting enhanced ENSO variability under a global warming scenario.

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“…2). Yu et al (2007) suggested that the most aggressive component of the batch method reductive solution is the citric acid. However, we found similar losses with the FT cleaning method and the use of buffered HYDRX not including citric acid.…”

Section: Carbonate Lossmentioning

confidence: 99%

Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments

Kraft

Hathorne

Weldeab

2013

Geochimica et Cosmochimica Acta

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The radiogenic neodymium (Nd) isotope composition of foraminiferal shells provides a powerful archive to investigate past changes in sources and mixing of water masses. However, seawater Nd isotope ratios extracted from foraminiferal shells can be biased by contaminant phases such as organic matter, silicates, or ferromanganese coatings, the removal of which requires rigorous multiple step cleaning of the samples. Here we investigate the efficiency of Flow Through and batch cleaning methods to extract seawater Nd isotope compositions from planktonic foraminifera in a shelf setting in the Gulf of Guinea that is strongly influenced by riverine sediment inputs. Nd isotope analyses of reductively and oxidatively cleaned mono-specific planktonic foraminiferal samples and reductively cleaned mixed benthic foraminifera were complemented by analyses of non-reductively cleaned mono-specific planktonic foraminiferal samples, Fe-Mn coatings of de-carbonated bulk sediment leachates, and the residual detrital fraction of the same sediment.Al/Ca and Mn/Ca ratios of fully cleaned foraminiferal samples reveal indistinguishable levels of cleaning efficiency between the batch and the Flow Through methods and the Nd isotope compositions obtained from application of both methods are identical within error. Furthermore, non-reductively cleaned foraminiferal samples have the same Nd isotope composition as reductively cleaned foraminifera at our study sites. Close to the Niger River mouth the Nd isotope composition of the foraminifera agree with the seawater Nd isotope composition of nearby stations. Based on the combined extracted Nd isotope signatures and element to calcium ratios, as well as rare earth element distribution patterns, we infer that the planktonic foraminiferal Nd isotope signatures reflect bottom water/pore water signatures. The isotopic composition of the bulk de-carbonated sediment leachates (Fe-Mn coatings) differs significantly from the foraminiferal data at this site and probably reflects particles that acquired their ferromanganese/pre-formed pre-formed/ferromanganese coatings in nearby rivers. Therefore, in such river influenced shelf settings foraminiferal shells should be used to obtain unbiased bottom seawater signatures.

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Preferential dissolution of benthic foraminiferal calcite during laboratory reductive cleaning

Cited by 87 publications

References 46 publications

Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate

Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate

Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state

Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments

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