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Calcium carbonate dissolution triggered by high productivity during the last glacial-interglacial interval at the deep western South Atlantic
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  • Jaime Y. Suárez-Ibarra,
  • Cristiane Fraga Frozza,
  • Sandro Monticelli Petró,
  • Pamela Lara Palhano,
  • Maria Alejandra Gomez Pivel
Jaime Y. Suárez-Ibarra
Univerzita Karlova

Corresponding Author:[email protected]

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Cristiane Fraga Frozza
Universidade Federal do Rio Grande do Sul
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Sandro Monticelli Petró
Universidade do Vale do Rio dos Sinos - UNISINOS
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Pamela Lara Palhano
Universidade Federal do Rio Grande do Sul
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Maria Alejandra Gomez Pivel
Universidade Federal do Rio Grande do Sul
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Studies reconstructing surface paleoproductivity and benthic conditions allow us to measure the effectiveness of the biological pump, an important mechanism in the global climate system. In order to assess surface productivity changes and their effect on the seafloor, we studied the core SAT-048A, recovered from the continental slope of the southernmost Brazilian continental margin, in the western South Atlantic. We assessed the sea surface productivity, the organic matter flux to the seafloor and the dissolution effects, based on micropaleontological (benthic and planktonic foraminifers, ostracods), geochemical (benthic and planktonic δ13C isotopes) and sedimentological data (carbonate and bulk sand content). Superimposed on the climate-induced changes related to the last glacial-interglacial transition, the reconstruction indicates paleoproductivity changes synchronized with the precessional cycle. From the reconstructed data, it was possible to identify high (low) surface productivity, high (low) organic matter flux to the seafloor, and high (low) dissolution rates of planktonic Foraminifera tests during the glacial (postglacial). Furthermore, within the glacial, enhanced productivity was associated with higher insolation values, explained by increased NE summer winds that promoted meandering and upwelling of the nutrient-rich South Atlantic Central Water. Changes in the Atlantic Meridional Overturning Circulation and the reorganization of bottom water masses could also have changed the CO3 2- saturation levels and have influenced the carbonate preservation. However, changes in the Uvigerina spp. δ13C values are very likely linked to the organic matter flux and not to the sea bottom dissolved inorganic matter δ13C values.
23 Mar 2022Published in Frontiers in Earth Science volume 10. 10.3389/feart.2022.830984