Abyssal hydrothermal alteration drives the evolution from simple alkanes to prebiotic molecular complexity

Area of Science:

• Geochemistry
• Astrobiology
• Organic Chemistry

Background:

• Abyssal hydrothermal vents are key sites for transforming simple reduced carbon into complex organic molecules.
• The exact organic geochemical continuum and evolutionary pathways are difficult to study due to intense hydrothermal alteration.

Purpose of the Study:

• To investigate the molecular relatedness and evolutionary patterns of organic molecules in abyssal hydrothermal vents.
• To bridge the gap between simple reduced carbon and the complex molecules necessary for prebiotic chemistry.

Main Methods:

• A metabolomics-inspired molecular fingerprinting strategy was employed.
• Mass spectral networking and hierarchical organization were used to construct a molecular phylogenetic tree.

Main Results:

• Organic molecules from different vent fields and activity states exhibit common molecular connection patterns.
• A progressive molecular evolution was observed, starting from alkanes and progressing to aromatics and complex heteroatom-bearing compounds.
• This evolution shows a systematic increase in molecular functionalization and polarity.

Conclusions:

• Hydrothermal systems play a significant role in generating life's essential feedstock on early Earth.
• The findings support the hypothesis that hydrothermal vents are crucial environments for prebiotic chemistry.
• This molecular framework can aid in the search for biosignatures in extraterrestrial environments like Mars and icy moons.