Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record

<p>Global weathering is the primary control of the Earth's climate over geologic timescales, converting atmospheric <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll...

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Main Authors: J. Renaudie, D. B. Lazarus
Format: Article
Language:English
Published: Copernicus Publications 2025-04-01
Series:Biogeosciences
Online Access:https://bg.copernicus.org/articles/22/1929/2025/bg-22-1929-2025.pdf
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author J. Renaudie
D. B. Lazarus
author_facet J. Renaudie
D. B. Lazarus
author_sort J. Renaudie
collection DOAJ
description <p>Global weathering is the primary control of the Earth's climate over geologic timescales, converting atmospheric <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>p</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="19d363e4a348c056939d011626862cf3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-1929-2025-ie00001.svg" width="24pt" height="12pt" src="bg-22-1929-2025-ie00001.png"/></svg:svg></span></span> into dissolved bicarbonate, with carbon sequestration by marine plankton as carbonate and organic carbon on the ocean floor. The accumulation rate of pelagic marine biogenic sediments is thus an indication of weathering history. Previous studies of Cenozoic pelagic sedimentation have yielded contrasting results, though most show a dramatic rise (up to 6 times) in rates over the Cenozoic. This contrasts with model expectations for approximate steady state in weathering, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>p</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="f970a075afd747993d97d753129f4038"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-1929-2025-ie00002.svg" width="24pt" height="12pt" src="bg-22-1929-2025-ie00002.png"/></svg:svg></span></span>, and sequestration over time. Here we show that the Cenozoic record of sedimentation recovered by deep-sea drilling has a strong, systematic bias towards lower rates of sedimentation with increasing age. When this bias is removed, accumulation rates are shown to actually decline by ca. 2 times over the Cenozoic. However, when accumulation area is adjusted for changes in available deposition area, global sediment flux to the deep sea is shown to have nearly doubled at the Eocene–Oligocene boundary but was otherwise essentially constant. Compilations of other metrics correlated to sedimentation rate (e.g. productivity, biotic composition) also must have a strong age bias, which will need to be considered in future paleoceanographic studies.</p>
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spelling doaj-art-b0d181df54e64f6e8003a0a6a156159d2025-08-20T02:24:30ZengCopernicus PublicationsBiogeosciences1726-41701726-41892025-04-01221929194610.5194/bg-22-1929-2025Cenozoic pelagic accumulation rates and biased sampling of the deep-sea recordJ. Renaudie0D. B. Lazarus1Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, GermanyMuseum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany<p>Global weathering is the primary control of the Earth's climate over geologic timescales, converting atmospheric <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>p</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="19d363e4a348c056939d011626862cf3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-1929-2025-ie00001.svg" width="24pt" height="12pt" src="bg-22-1929-2025-ie00001.png"/></svg:svg></span></span> into dissolved bicarbonate, with carbon sequestration by marine plankton as carbonate and organic carbon on the ocean floor. The accumulation rate of pelagic marine biogenic sediments is thus an indication of weathering history. Previous studies of Cenozoic pelagic sedimentation have yielded contrasting results, though most show a dramatic rise (up to 6 times) in rates over the Cenozoic. This contrasts with model expectations for approximate steady state in weathering, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>p</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="f970a075afd747993d97d753129f4038"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-1929-2025-ie00002.svg" width="24pt" height="12pt" src="bg-22-1929-2025-ie00002.png"/></svg:svg></span></span>, and sequestration over time. Here we show that the Cenozoic record of sedimentation recovered by deep-sea drilling has a strong, systematic bias towards lower rates of sedimentation with increasing age. When this bias is removed, accumulation rates are shown to actually decline by ca. 2 times over the Cenozoic. However, when accumulation area is adjusted for changes in available deposition area, global sediment flux to the deep sea is shown to have nearly doubled at the Eocene–Oligocene boundary but was otherwise essentially constant. Compilations of other metrics correlated to sedimentation rate (e.g. productivity, biotic composition) also must have a strong age bias, which will need to be considered in future paleoceanographic studies.</p>https://bg.copernicus.org/articles/22/1929/2025/bg-22-1929-2025.pdf
spellingShingle J. Renaudie
D. B. Lazarus
Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record
Biogeosciences
title Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record
title_full Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record
title_fullStr Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record
title_full_unstemmed Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record
title_short Cenozoic pelagic accumulation rates and biased sampling of the deep-sea record
title_sort cenozoic pelagic accumulation rates and biased sampling of the deep sea record
url https://bg.copernicus.org/articles/22/1929/2025/bg-22-1929-2025.pdf
work_keys_str_mv AT jrenaudie cenozoicpelagicaccumulationratesandbiasedsamplingofthedeepsearecord
AT dblazarus cenozoicpelagicaccumulationratesandbiasedsamplingofthedeepsearecord