Historic fossils are revealing sudden chemical survivors, difficult long-held assumptions about how organic carbon is preserved over Earth’s historical past.
Trilobites are a number of the most recognizable fossils on Earth, but they’ve principally been handled as mineral snapshots of lengthy vanished marine life. Now, a world staff led by UT San Antonio stories one thing far rarer: chemical proof of chitin preserved inside trilobite fossils which are greater than 500 million years outdated. Chitin is the robust natural materials that helps construct trendy crab shells and bug exoskeletons, and that is the primary confirmed time it has been present in trilobites.
The work was led by Elizabeth Bailey, assistant professor of earth and planetary sciences at UT San Antonio. Past including a brand new layer of element to those traditional fossils, the outcomes level to a much bigger story about how sure biomolecules can endure deep time and what that sturdiness would possibly imply for Earth’s long-term carbon storage.
Chitin is among the many most typical natural polymers made by residing organisms, second solely to cellulose, and it’s best identified for giving energy to many animals and likewise to fungal cell partitions. For a very long time, researchers assumed chitin wouldn’t final lengthy after loss of life as a result of microbes and chemical breakdown are inclined to dismantle complicated natural supplies shortly.
The brand new research provides to a rising physique of proof that some organic polymers can persist within the geologic document for much longer than anticipated, particularly when they’re shielded by the suitable burial circumstances.
“This research provides to rising proof that chitin survives far longer within the geologic document than initially realized,” Bailey stated. “Past paleontology, this has vital implications for understanding how natural carbon is saved in Earth’s crust over geologic time.”
Bailey contributed a geochemical and planetary science method to the undertaking, drawing on her background in stratigraphy, subject geology, and research of how organic supplies work together with Earth’s carbon cycle throughout billions of years.
“I used to be motivated to pursue this work from my perspective as a planetary scientist fascinated about how natural molecules play a task in planetary geochemical processes,” stated Bailey. “My collaborators specialise in trendy chitin analytics, and so they had been excited to use more and more delicate strategies to such an historical and iconic fossil group.”
The analysis was not too long ago printed in PALAIOS, a month-to-month journal that focuses on how life has formed Earth’s historical past by means of paleontological and sedimentological information.
How carbon is saved
Though the research examined solely a restricted variety of fossils, its significance extends past trilobites. Studying how natural carbon can persist in widespread geological environments helps scientists higher reconstruct Earth’s carbon cycle and perceive how carbon is of course saved inside the planet’s crust.
The findings might also be related to discussions about local weather and carbon storage at this time. Limestones, which type from the buildup of organic materials and have been extensively used as building supplies all through human historical past, typically comprise organisms that produce chitin.
“When individuals take into consideration carbon sequestration, they have an inclination to consider bushes,” Bailey stated. “However after cellulose, chitin is taken into account Earth’s second most plentiful naturally occurring polymer. Proof that chitin can survive for tons of of tens of millions of years exhibits that limestones are a part of long-term carbon sequestration and related to understanding Earth’s carbon dioxide ranges.”
Early Earth lab
The analysis started previous to Bailey’s appointment at UT San Antonio, throughout her postdoctoral fellowship on the College of California, Santa Cruz, and was supported by the Heising-Simons Basis’s 51 Pegasi b Fellowship in Planetary Astronomy.
Whereas no different UT San Antonio school or college students had been straight concerned on this particular research, Bailey anticipates that the findings will create new alternatives inside the college’s Early Earth Lab for future student-driven analysis into the long-term survival of natural molecules in geological supplies.
In 2020, Bailey earned her Ph.D. in planetary science at Caltech and obtained the 51 Pegasi b Postdoctoral Fellowship in Planetary Astronomy from the Heising-Simons Basis, which she took to UC Santa Cruz. In her postdoc, she branched out from her very theoretical dissertation work into utilizing laboratory-based strategies to review planetary supplies. In 2025, Bailey accepted a tenure-track professorship at UT San Antonio within the Division of Earth and Planetary Sciences.
Bailey’s analysis focuses on how the Photo voltaic System, together with Earth, fashioned and altered over time. Her Early Earth Lab builds laptop fashions and carries out laboratory-based chemical analyses of planetary supplies, together with meteorites that fashioned within the Photo voltaic System and historical rocks from Earth.
Reference: “Proof for Surviving Chitin in Cambrian Trilobites from the Carrara Formation, Western North America” by Elizabeth Bailey, Mikhail Tsurkan, Krzysztof Nowacki, Teofil Jesionowski and Hermann Ehrlich, 24 December 2025, PALAIOS.
DOI: 10.2110/palo.2024.025
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