Detection of Peptidic Sequences in the Ancient Acidic Sediments of Río Tinto, Spain

Abstract

Biomarkers are molecules that are produced by or can be associated with biological activities. They can be used as tracers that give us an idea of the ancient biological communities that produced them, the paleoenvironmental conditions where they lived, or the mechanism involved in their transformation and preservation. As a consequence, the preservation potential of molecules over time depends largely on their nature, but also on the conditions of the environment, which controls the decomposition kinetics. In this context, proteins and nucleic acids, which are biomolecules bearing biological information, are among the most labile molecules. In this research, we report the presence of short-chained peptides obtained from extracts of ferruginous sedimentary deposits that have been produced under the acidic and oxidizing solutions of Río Tinto, Spain. These preliminary results go against the paradigmatic idea that considers the acidic and oxidizing environments inappropriate for the preservation of molecular information.

Río Tinto: A Geochemical and Mineralogical Terrestrial Analogue of Mars

“…The recent detection of protein fragments and other organic molecules [ 54 , 55 ] in the ancient terraces of the Rio Tinto basin evidences that its acidic and ferruginous environment promotes the preservation of molecules bearing information about the producing organism that inhabited this extreme environment over the last million years.…”

The Fate of Lipid Biosignatures in a Mars-Analogue Sulfur Stream

“…It has been suggested that the preservation of life’s organic compounds may be difficult in Fe 3+ mineral-containing sedimentary deposits owing to a predisposition for oxidation reactions 13 , 14 , yet contrary evidence has been provided by molecular organic extracts of ferruginous sediments from recent 15 and ancient 16 deposits from natural acid streams on Earth (e.g. Rio Tinto), while another study found that up to 21% of organic carbon in sediment is bound to Fe-bearing phases 17 .…”

Unveiling microbial preservation under hyperacidic and oxidizing conditions in the Oligocene Rio Tinto deposit

“…1 ), which is considered one of the sources of the acidic waters of Rio Tinto 10 . Indirect rock dating using geomagnetic techniques 25 suggests that the gossan materials in this location were formed through the acidic weathering of Carboniferous sulfide orebodies 26 during the late Oligocene 25 . Such alteration coincides with a thermal climatic event 27 that likely enhanced the acidic weathering of the orebodies.…”