Identification

Title

Coupled decline in ocean pH and carbonate saturation during the Palaeocene–Eocene Thermal Maximum

Abstract

<div class="c-article-section__content" style="box-sizing:inherit;margin-bottom:40px;padding-top:8px;" id="Abs1-content"><p style="box-sizing:inherit;margin-bottom:24px;margin-top:0px;overflow-wrap:break-word;word-break:break-word;">The Palaeocene–Eocene Thermal Maximum, a climate event 56 million years ago, was characterized by rapid carbon release and extensive ocean acidification. However, our understanding of acidification and the evolution of ocean saturation states continues to be hindered by considerable uncertainties, primarily stemming from the limited availability of proxy data. Under such conditions, data assimilation allows for an internally consistent assessment of atmospheric CO<sub style="bottom:-0.25em;box-sizing:inherit;font-size:13.5px;line-height:0;position:relative;vertical-align:baseline;">2</sub> changes, ocean acidification and carbonate saturation state during this period. Here, we present a reconstruction of the Palaeocene–Eocene Thermal Maximum carbon cycle perturbation by assimilating seafloor sediment CaCO<sub style="bottom:-0.25em;box-sizing:inherit;font-size:13.5px;line-height:0;position:relative;vertical-align:baseline;">3</sub> and sea surface temperature proxy data with simulations from an Earth system model, which includes a comprehensive carbonate system. Our reconstructions indicate a substantial increase in atmospheric CO<sub style="bottom:-0.25em;box-sizing:inherit;font-size:13.5px;line-height:0;position:relative;vertical-align:baseline;">2</sub> from 890 ppm (95% credible interval: 680–1,170 ppm) to 1,980 ppm (1,680–2,280 ppm), coupled with a notable decline in pH (0.46 units, ranging from 0.31 to 0.63 units) and surface-water calcite saturation state, decreasing from 10.2 (7.5–12.8) in the pre-event period to 3.8 (2.8–5.1) during the thermal maximum. Carbonate undersaturation intensified substantially in high-latitude surface waters during the Palaeocene–Eocene Thermal Maximum, paralleling the current decline in Arctic aragonite saturation driven by anthropogenic CO<sub style="bottom:-0.25em;box-sizing:inherit;font-size:13.5px;line-height:0;position:relative;vertical-align:baseline;">2</sub> emissions.</p></div></div></section><div class="js-context-bar-sticky-point-mobile" style="-webkit-text-stroke-width:0px;background-color:rgb(255, 255, 255);box-sizing:inherit;color:rgb(34, 34, 34);font-family:Harding, Palatino, serif;font-size:18px;font-style:normal;font-variant-caps:normal;font-variant-ligatures:normal;font-weight:400;letter-spacing:normal;orphans:2;text-align:start;text-decoration-color:initial;text-decoration-style:initial;text-decoration-thickness:initial;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;" data-track-context="article body"> 

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.net/ark:/85065/d7c82fnz

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

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Text

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title

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reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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date type

publication

effective date

2024-12-01T00:00:00Z

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<span style="font-family:Arial;font-size:10pt;font-style:normal;" data-sheets-root="1">Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</span>

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

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