Thermal and nutrient stress drove Permian-Triassic shallow marine extinctions

Impact Statement: What are the biggest consequences of climate change for marine ecosystems? Is it deoxygenation, thermal stress, ocean acidification, or any combination thereof? The Permian-Triassic climate crisis was an episode of severe and rapid climate warming with similarities to the worst-case projected scenarios for the near future. To better understand which consequences of this climate event led to one of the most severe biodiversity crisis ever, we implemented a novel approach of statistically integrating high-resolution fossil data with high-resolution geochemical data. Our results demonstrate that for equatorial, marine ecosystems, oxygen isotope (temperature proxy) and cadmium isotope (primary productivity proxy) dynamics best explain the marine extinction. This suggests that the biggest threats to past and modern biodiversity in these settings are the impacts of thermal and nutrient stress, as
well as associated trophic knock-on effects.

Abstract: The Permian-Triassic climate crisis can provide key insights into the potential impact of horizon threats to modern-day biodiversity. This crisis coincides with the same extensive environmental changes that threaten modern marine ecosystems (i.e., thermal stress, deoxygenation and ocean acidification), but the primary drivers of extinction are currently unknown. To understand which factors caused extinctions, we conducted a data analysis to quantify the relationship (anomalies, state-shifts and trends) between geochemical proxies and the fossil record at the most intensively studied locality for this event, the Meishan section, China. We found that δ18Oapatite (paleotemperature proxy) and δ 32 114/110Cd (primary productivity proxy) best explain changes in species diversity and species composition in Meishan’s paleoequatorial setting. These findings suggest that the physiological stresses induced by ocean warming and nutrient availability played a predominant role in driving equatorial marine extinctions during the Permian-Triassic event. This research enhances our understanding of the interplay between environmental changes and extinction dynamics during a past climate crisis, presenting an outlook for extinction threats in the worst-case “Shared Socioeconomic Pathways (SSP5-8.5) scenario.

Foster W. J., Frank A. B., Li Q., Danise S., Wang X. & Peckmann J., 2024. Thermal and nutrient stress drove Permian-Triassic shallow marine extinctions. Cambridge Prisms: Extinction: 1-25. Article.

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