Marine temperatures underestimated for past greenhouse climate.

Autor: Vickers ML; Faculty of Science, Geology Section, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen K, Denmark. mlv@ign.ku.dk., Bernasconi SM; Geologisches Institut, Dep. Erdwissenschaften, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland., Ullmann CV; Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK.; Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, TR10 9FE, Cornwall, UK., Lode S; Department of Petrology and Economic Geology, Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350, Copenhagen K, Denmark., Looser N; Geologisches Institut, Dep. Erdwissenschaften, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland., Morales LG; Geologisches Institut, Dep. Erdwissenschaften, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland.; Scientific Centre for Optical and Electron Microscopy (ScopeM), ETH Zürich, Otto-Stern-Weg 3, 8093, Zürich, Switzerland., Price GD; School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK., Wilby PR; British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK.; School of Geography, Geology and the Environment, University of Leicester, University Road, Leicester, LE1 7RH, UK., Hougård IW; Faculty of Science, Geology Section, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen K, Denmark., Hesselbo SP; Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, TR10 9FE, Cornwall, UK., Korte C; Faculty of Science, Geology Section, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen K, Denmark.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2021 Sep 27; Vol. 11 (1), pp. 19109. Date of Electronic Publication: 2021 Sep 27.
DOI: 10.1038/s41598-021-98528-1
Abstrakt: Understanding the Earth's climate system during past periods of high atmospheric CO 2 is crucial for forecasting climate change under anthropogenically-elevated CO 2 . The Mesozoic Era is believed to have coincided with a long-term Greenhouse climate, and many of our temperature reconstructions come from stable isotopes of marine biotic calcite, in particular from belemnites, an extinct group of molluscs with carbonate hard-parts. Yet, temperatures reconstructed from the oxygen isotope composition of belemnites are consistently colder than those derived from other temperature proxies, leading to large uncertainties around Mesozoic sea temperatures. Here we apply clumped isotope palaeothermometry to two distinct carbonate phases from exceptionally well-preserved belemnites in order to constrain their living habitat, and improve temperature reconstructions based on stable oxygen isotopes. We show that belemnites precipitated both aragonite and calcite in warm, open ocean surface waters, and demonstrate how previous low estimates of belemnite calcification temperatures has led to widespread underestimation of Mesozoic sea temperatures by ca. 12 °C, raising estimates of some of the lowest temperature estimates for the Jurassic period to values which approach modern mid-latitude sea surface temperatures. Our findings enable accurate recalculation of global Mesozoic belemnite temperatures, and will thus improve our understanding of Greenhouse climate dynamics.
(© 2021. The Author(s).)
Databáze: MEDLINE
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