98-12 Assessing thermal stress during the Permian-Triassic mass extinction through ostracods from the Southern Alps (Italy)

Session: Linking Biodiversity Loss to Environmental Stressors Through Integrated Approaches

Presenting Author:

Mónica Alejandra Gómez Correa

Authors:

Gómez Correa, Mónica Alejandra¹, Frank, Anja B.², Wiedenbeck, Michael³, Gliwa, Jana⁴, Korn, Dieter⁵, Prinoth, Herwig⁶, Kustatscher, Evelyn⁷, Foster, William J.⁸

(1) Department of Earth System Sciences, University of Hamburg, Hamburg, Germany, (2) Department of Earth System Sciences, University of Hamburg, Hamburg, Germany, (3) Helmholtz Centre for Geosciences, Potsdam, Germany, (4) Institute of Geological Sciences, Palaeontology Section, Freie Universität Berlin, Berlin, Germany, (5) Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany, (6) Museum Ladin, San Martin de Tor / St. Martin in Thurn/ San Martino in Badia, Italy, (7) Sammlungs- und Forschungszentrum, Tiroler Landesmuseen, Hall in Tirol, Austria, (8) Department of Earth System Sciences, University of Hamburg, Hamburg, Germany,

Abstract:

The Permian-Triassic mass extinction, which occurred approximately 252 million years ago, was the Earth's most severe known biotic crisis. During the extinction period, environmental changes, such as thermal stress, deoxygenation, and ocean acidification, are hypothesized to have played crucial roles in driving the crisis. Among the affected taxa, ostracods were abundant, diverse and widely distributed microfossils across the extinction. Their fossil record provides valuable insights into marine ecosystem responses to such severe environmental changes and helps identify the primary drivers of this catastrophic extinction. Ostracod carapaces are composed of low-Mg calcite, a stable and reliable archive of seawater conditions. This study uses secondary ion mass spectrometry (SIMS) to analyze the geochemical signals preserved in ostracod carapaces from Permian-Triassic carbonate ramp successions in the Southern Alps, Italy. We measured δ¹⁸O_ostracod as a proxy for paleotemperature and δ¹³C_ostracod to assess perturbations in the carbon cycle. Our results reveal that the δ¹³C_ostracod data record a decreasing trend in δ¹³C_carbonate of abiotic carbonate typical for the end Permian, but with a consistent negative offset likely caused by vital effects. Further, the recorded δ¹⁸O_ostracod values decrease across the investigated interval, suggesting a gradual increase in sea surface temperatures, which agrees with previously measured δ¹⁸O_ostracod data from other localities. These findings highlight the value of ostracod geochemistry as an indicator of temperature change. Further analyses of these microfossils have the potential to enhance our understanding of marine ecosystem responses to temperature changes in the past, present and future.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-4793

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