Deep Pacific storage of respired carbon during the last ice age: Perspectives from bottom water oxygen reconstructions

Jacobel, A.W.; Anderson, R.F.; Jaccard, S. L.; McManus, J.F.; Pavia, F.J.; Winckler, G. (2020). Deep Pacific storage of respired carbon during the last ice age: Perspectives from bottom water oxygen reconstructions. Quaternary science reviews, 230, p. 106065. Elsevier 10.1016/j.quascirev.2019.106065

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Reconstructions of past changes in dissolved oxygen concentrations in the abyssal ocean are of interest to paleoceanographers because of their potential to help characterize and quantify the transfer of carbon between the atmosphere and the deep ocean. This potential, derived from the stoichiometric relation- ship between oxygen consumption and the regeneration of organic matter, has recently been expanded by compilations of core top observations for two proxies: the d13C gradient between coeval infaunal and epifaunal benthic foraminifera (Dd13C), and biomarker preservation. Here, we review these newer proxies, and the more established redox proxy authigenic uranium (aU), to critically evaluate our un- derstanding of the controls on proxy signal production and preservation. We locate our work in the equatorial Pacific, presenting both new data and a compilation of existing records from thirty-two sediment cores to draw semi-quantitative conclusions about bottom water oxygen and respired car- bon concentrations over the last glacial period. We find that the biogeochemical limitations on these proxies may be more substantial than previously appreciated, and therefore suggest several best-practice recommendations for their application. Despite the recognized data limitations, the compilation iden- tifies the glacial Pacific Ocean as a dominant sink for CO2 at all depths below the modern oxygen minimum zone. Our review emphasizes the importance of multiproxy reconstructions, informed by site- specific records of paleoproductivity, in drawing coherent, internally consistent conclusions about glacial ocean oxygenation and carbon storage.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Jaccard, Samuel

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0277-3791

Publisher:

Elsevier

Language:

English

Submitter:

Samuel Jaccard

Date Deposited:

04 Feb 2020 15:30

Last Modified:

09 Feb 2020 02:46

Publisher DOI:

10.1016/j.quascirev.2019.106065

BORIS DOI:

10.7892/boris.139759

URI:

https://boris.unibe.ch/id/eprint/139759

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