Coral thermal tolerances constrain extreme Mesozoic–Cenozoic hothouse reconstructions
Leonard J, Zahirovic S, Salles T, Dimitrijevic D, Merdith AS, Dowding E (2026)
Publication Language: English
Publication Type: Journal article, Original article
Publication year: 2026
Journal
Book Volume: 699
DOI: https://doi.org/10.1016/j.palaeo.2026.113957
Open Access Link: https://doi.org/10.1016/j.palaeo.2026.113957
Abstract
Reef-building hard corals today occupy a thermal Sea Surface Temperature (SST) niche between about 22–30°" role="presentation" style="display: inline-block; line-height: normal; font-size: 14.4px; font-size-adjust: none; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border-width: 0px; position: relative;">C. If this niche is evolutionarily conserved, their past geographic distribution should be restricted to bands of limited SSTs. Here we test if this simple biological constraint can act as an independent check on paleotemperature reconstructions for the post-Pangea timeframe. We run an ensemble of climate simulations for every 10 Myr from 250–0 Ma across eight atmospheric CO2 scenarios (100–4480 ppm) and two paleogeographic models to quantify coral habitat suitability based on modern SST preferences. We construct a best-fit paleotemperature curve composed of simulations that correspond to the highest average coral suitability at each age snapshot. Our curve fits within the envelope of past temperatures suggested by other published paleotemperature reconstructions. The paleotemperature curve of Scotese et al. (2021) is considered the closest match to our coral-constrained curve with the two deviating from one another by an average 6%. On the other hand, paleotemperature curves that rely on quantitative geochemical SST data (e.g. Grossman and Joachimski, 2022 and Song et al., 2019) generally have a poor fit, with Jurassic and Cenozoic SSTs 13% and 17% cooler. Furthermore, our findings do not support estimates of extreme global temperatures in Cretaceous hothouses, instead suggesting more modest GMSTs of about 20–26°" role="presentation" style="display: inline-block; line-height: normal; font-size: 14.4px; font-size-adjust: none; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border-width: 0px; position: relative;">C at these times. We find that photosymbiotic reef corals would have needed to adjust the upper bound of their thermal preference to approximately 35°" role="presentation" style="display: inline-block; line-height: normal; font-size: 14.4px; font-size-adjust: none; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border-width: 0px; position: relative;">C in order to better match the warm temperatures predicted by Judd et al. (2024). Our results imply coral distributions encode a strong low-latitude temperature filter that could reject some extreme paleotemperature estimates, and that cross-validation of paleotemperature reconstructions using independent biologically grounded constraints is both possible and necessary.
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Australia (AU)How to cite
APA:
Leonard, J., Zahirovic, S., Salles, T., Dimitrijevic, D., Merdith, A.S., & Dowding, E. (2026). Coral thermal tolerances constrain extreme Mesozoic–Cenozoic hothouse reconstructions. Palaeogeography, Palaeoclimatology, Palaeoecology, 699. https://doi.org/https://doi.org/10.1016/j.palaeo.2026.113957
MLA:
Leonard, Jonathon, et al. "Coral thermal tolerances constrain extreme Mesozoic–Cenozoic hothouse reconstructions." Palaeogeography, Palaeoclimatology, Palaeoecology 699 (2026).
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