A record of bottom water temperature and seawater δ18O for the Southern Ocean over the past 440kyr based on Mg/Ca of benthic foraminiferal Uvigerina spp.

Elderfield, Henry; Greaves, Mervyn; Barker, Stephen; Hall, Ian Robert; Tripati, Aradhna; Ferretti, Patrizia; Crowhurst, Simon J; Booth, Linda; Daunt, C

doi:10.1016/j.quascirev.2009.07.013

Cited by 139 publications

(165 citation statements)

References 45 publications

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“…The most probable warm water masses that can mix with sinking southern-sourced waters during the LGM are Drake Passage through flow waters from the Pacific. Although it has been shown that Pacific deep water was not significantly warmer than freezing (18,28), it remains to be determined whether Pacific intermediate waters were significantly warmer and had an influence on southern-sourced deep water in the Atlantic. Alternatively, the source of warmth in the deep South Atlantic may be derived from the accumulation of geothermal heat, assuming that the deep ocean is stagnant and cannot lose heat to the surface (29).…”

Section: Processes Controlling the Physical Properties Of Water Massementioning

confidence: 98%

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Evolution of South Atlantic density and chemical stratification across the last deglaciation

Roberts

Gottschalk

Skinner

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Section: Processes Controlling the Physical Properties Of Water Massementioning

confidence: 98%

“…are used to estimate benthic seawater temperature (18) and to calculate the δ 18 O of deep and intermediate water masses (hereafter referred to as δ w ). Temperature and δ w (closely related to seawater salinity) are combined to produce a continuous record of the evolution of the density gradient in the South Atlantic over the last deglaciation (Methods).…”

mentioning

confidence: 99%

Evolution of South Atlantic density and chemical stratification across the last deglaciation

Roberts

Gottschalk

Skinner

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Another Mg/Ca study also suggests that Pacific PGM deep-sea temperatures were~1 C lower than for the LGM (Martin et al, 2002). These anomalies fall well within the uncertainties of Mg/Ca calibrations, which remain poorly constrained at these low temperatures, especially because near-freezing temperatures require extrapolation outside the present-day calibration window for the method (Martin et al, 2002;Elderfield et al, 2010). More importantly, it is difficult to imagine how deep-sea temperatures could have been much lower than in the LGM because (pressurecorrected) conditions are thought to have been close to freezing in much of the LGM deep sea already (Siddall et al, 2010).…”

Section: The Global D 18 O:sea-level/ice-volume Relationshipmentioning

confidence: 60%

“…Martin et al, 2002;Elderfield et al, 2012). These are derived from benthic foraminiferal carbonate d 18 O data (d c ) that are corrected for temperature changes using Mg/Ca analyses of the same benthic foraminifera (Martin et al, 2002;Sosdian and Rosenthal, 2009;Elderfield et al, 2010Elderfield et al, , 2012 (Elderfield et al, 2012). Specifically, we use a probabilistic assessment of that record, which highlights the overall signal structure, and accounts for both chronological and sea-level uncertainties (Fig.…”

Section: Denton and Hughes 2002mentioning

confidence: 99%

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

Rohling

Hibbert

Williams

et al. 2017

Quaternary Science Reviews

100

115

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Arctic ice shelf Last Interglacial Glacioisostatic adjustment a b s t r a c t Studies of past glacial cycles yield critical information about climate and sea-level (ice-volume) variability, including the sensitivity of climate to radiative change, and impacts of crustal rebound on sealevel reconstructions for past interglacials. Here we identify significant differences between the last and penultimate glacial maxima (LGM and PGM) in terms of global volume and distribution of land ice, despite similar temperatures and radiative forcing. Our analysis challenges conventional views of relationships between global ice volume, sea level, seawater oxygen isotope values, and deep-sea temperature, and supports the potential presence of large floating Arctic ice shelves during the PGM. The existence of different glacial 'modes' calls for focussed research on the complex processes behind ice-age development. We present a glacioisostatic assessment to demonstrate how a different PGM ice-sheet configuration might affect sea-level estimates for the last interglacial. Results suggest that this may alter existing last interglacial sea-level estimates, which often use an LGM-like ice configuration, by several metres (likely upward).

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“…More recent studies raise further questions about the validity of the assumed calcification depths of infaunal species. For example, it has been assumed that Mg / Ca data from infaunal foraminifera are relatively insulated from the effect of bottom water [CO 2− 3 ] changes (Elderfield et al, 2006(Elderfield et al, , 2010. However, Weldeab et al (2016) have shown that infaunal Globobulimina spp.…”

Section: Introductionmentioning

confidence: 99%

“Live” (stained) benthic foraminiferal living depths, stable isotopes, and taxonomy offshore South Georgia, Southern Ocean: implications for calcification depths

Dejardin

Kender

Allen

et al. 2018

J. Micropalaeontol.

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Abstract. It is widely held that benthic foraminifera exhibit species-specific calcification depth preferences, with their tests recording sediment pore water chemistry at that depth (i.e. stable isotope and trace metal compositions). This assumed depth-habitat-specific pore water chemistry relationship has been used to reconstruct various palaeoenvironmental parameters, such as bottom water oxygenation. However, many deepwater foraminiferal studies show wide intra-species variation in sediment living depth but relatively narrow intra-species variation in stable isotope composition. To investigate this depth-habitat-stable-isotope relationship on the shelf, we analysed depth distribution and stable isotopes of "living" (Rose Bengal stained) benthic foraminifera from two box cores collected on the South Georgia shelf (ranging from 250 to 300 m water depth). We provide a comprehensive taxonomic analysis of the benthic fauna, comprising 79 taxonomic groupings. The fauna shows close affinities with shelf assemblages from around Antarctica. We find "live" specimens of a number of calcareous species from a range of depths in the sediment column. Stable isotope ratios (δ 13 C and δ 18 O) were measured on stained specimens of three species, Astrononion echolsi, Cassidulinoides porrectus, and Buccella sp. 1, at 1 cm depth intervals within the downcore sediment sequences. In agreement with studies in deep-water settings, we find no significant intra-species variability in either δ 13 C foram or δ 18 O foram with sediment living depth on the South Georgia shelf. Our findings add to the growing evidence that infaunal benthic foraminiferal species calcify at a fixed depth. Given the wide range of depths at which we find "living", "infaunal" species, we speculate that they may actually calcify predominantly at the sediment-seawater interface, where carbonate ion concentration and organic carbon availability is at a maximum.

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A record of bottom water temperature and seawater δ18O for the Southern Ocean over the past 440kyr based on Mg/Ca of benthic foraminiferal Uvigerina spp.

Cited by 139 publications

References 45 publications

Evolution of South Atlantic density and chemical stratification across the last deglaciation

Evolution of South Atlantic density and chemical stratification across the last deglaciation

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

“Live” (stained) benthic foraminiferal living depths, stable isotopes, and taxonomy offshore South Georgia, Southern Ocean: implications for calcification depths

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