Protocells reproduce morphological and chemical signatures of early microfossils
- 1Dublin City University
Abstract
Identification of early microfossils relies on morphological and chemical criteria assumed to be unique to life, but whether abiotic microstructures can satisfy these criteria has not been rigorously tested. Hydrothermal environments preserve microfossils but are also efficient geochemical reactors for abiotic reactions. Protocells form in hydrothermal conditions and represent a plausible abiotic analogue to early microfossils. Here we show that protocells form from simple organic molecules in low-temperature, alkaline hydrothermal conditions in the presence of silica and produce spheres, filaments, and lenticular structures that strongly resemble the morphology of purported microfossils in Archaean silica cherts. FTIR spectroscopy provides overlapping chemical signatures across protocells, microorganisms, and geologic microstructures. In addition, the FTIR R3/2 ratio, a chemometric index often used to discriminate domains and determine biogenicity, identifies eight different protocell systems as either bacterial, archaeal, or eukaryotic. These data suggest that protocells preserved in ancient hydrothermal deposits can satisfy current biogenicity criteria, undermining the reliability of interpretations of the early fossil record. As life detection is the primary objective for current space exploration endeavours, robust biogenicity protocols that account for abiotic signatures are essential.
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BibTeX
@misc{chalonge2026protocells,
title = {{Protocells reproduce morphological and chemical signatures of early microfossils}},
author = {L. Gillet de Chalonge and K. Field and R. Dignam and M. Coutant and C. Loron and M. A. van Zuilen and S. F. Jordan},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.28.753251},
url = {https://www.biorxiv.org/content/10.64898/2026.09.28.753251v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Protocells reproduce morphological and chemical signatures of early microfossils
AU - L. Gillet de Chalonge
AU - K. Field
AU - R. Dignam
AU - M. Coutant
AU - C. Loron
AU - M. A. van Zuilen
AU - S. F. Jordan
PY - 2026
DA - 2026/09/28
PB - bioRxiv
DO - 10.64898/2026.09.28.753251
UR - https://www.biorxiv.org/content/10.64898/2026.09.28.753251v1
AB - Identification of early microfossils relies on morphological and chemical criteria assumed to be unique to life, but whether abiotic microstructures can satisfy these criteria has not been rigorously tested. Hydrothermal environments preserve microfossils but are also efficient geochemical reactors for abiotic reactions. Protocells form in hydrothermal conditions and represent a plausible abiotic analogue to early microfossils. Here we show that protocells form from simple organic molecules in low-temperature, alkaline hydrothermal conditions in the presence of silica and produce spheres, filaments, and lenticular structures that strongly resemble the morphology of purported microfossils in Archaean silica cherts. FTIR spectroscopy provides overlapping chemical signatures across protocells, microorganisms, and geologic microstructures. In addition, the FTIR R3/2 ratio, a chemometric index often used to discriminate domains and determine biogenicity, identifies eight different protocell systems as either bacterial, archaeal, or eukaryotic. These data suggest that protocells preserved in ancient hydrothermal deposits can satisfy current biogenicity criteria, undermining the reliability of interpretations of the early fossil record. As life detection is the primary objective for current space exploration endeavours, robust biogenicity protocols that account for abiotic signatures are essential.
ER -