How Algae Helped Some Life Outlast Extinction

Source: AGU Advances

Earth’s largest mass extinction occurred round 252 million years in the past, wiping out nearly all of marine and terrestrial life, disrupting the worldwide carbon cycle for a number of hundred thousand years, and incomes the title “the Great Dying.” Global warming, altering temperature gradients, shifts in nutrient biking, and oxygen depletion worn out 81% of all marine life on the time.

But cooler, comparatively excessive latitude marine environments might have been refuges for species escaping risky local weather situations elsewhere. Buchwald et al. examined rock samples from the Arctic archipelago of Svalbard, Norway, and recognized excessive ranges of lipid biomarkers in rocks dated quickly after the Permian-Triassic extinction. Though the precise organism producing these molecules is unknown, it’s possible a bunch of phytoplankton. This discovering means that the cooler waters of the paleo-ocean allowed this major producer to bloom and maintain remaining sea life.

The researchers collected 32 rock samples from Svalbard taken from layers fashioned pre- and postextinction and in contrast them with samples taken from different areas, corresponding to northern Italy, southern China, and Türkiye. All signify hotter areas surrounding the prehistoric Tethys Ocean, a precursor to the trendy Indian Ocean and Mediterranean Sea. The group examined the samples for C₃₃–n-alkylcyclohexane (C₃₃–n-ACH) and phytanyl toluene, molecular fossils that act like fingerprints of historical marine life.

In the Svalbard samples dated after the Permian-Triassic extinction occasion, C₃₃–n-ACH ranges have been 10 occasions larger than in samples from earlier than the occasion. The researchers word that the preextinction samples possible skilled extra degradation, however that alkylcyclohexane biomarkers are comparatively immune to such degradation, which means the upper quantities detected after the extinction level to a real enhance within the biomarker. In the samples taken from hotter areas, far much less C₃₃–n-ACH total was detected, however the same enhance in abundance after the extinction occasion occurred.

Phytanyl toluene was largely absent from the Svalbard samples earlier than the extinction and confirmed a equally dramatic enhance within the extinction’s aftermath. It was not current within the tropical samples, suggesting that it was produced by a distinct phytoplankton than the species that produced the C₃₃–n-ACH.

Overall, these findings counsel that the phytoplankton producers of those biomarkers remained steady and thrived in cooler waters throughout a time when hotter waters have been unable to assist important marine life, the researchers say. (AGU Advances, https://doi.org/10.1029/2025AV001785, 2025)

—Rebecca Owen (@beccapox.bsky.social), Science Writer

Citation: Owen, R. (2025), How algae helped some life outlast extinction, Eos, 106, https://doi.org/10.1029/2025EO250426. Published on 13 November 2025.

Text © 2025. AGU. CC BY-NC-ND 3.0
Except the place in any other case famous, photographs are topic to copyright. Any reuse with out categorical permission from the copyright proprietor is prohibited.

Related