Concomitant formation of protocells and prebiotic compounds under a plausible early Earth atmosphere.

Revealing the origin of life and unambiguously detecting fossil remains of the earliest organisms are closely related aspects of the same scientific research. The synthesis of prebiotic molecular building blocks of life and the first compartmentalization into protocells have been considered two events apart in time, space, or both. We conducted lightning experiments in borosilicate reactors filled with a mixture of gases mimicking plausible geochemical conditions of early Earth.

Multi-analytical characterization of an oncoid from a high altitude hypersaline lake using techniques employed in the Mars2020 and Rosalind Franklin missions on Mars.

In this work, a geological sample of great astrobiological interest was studied through analytical techniques that are currently operating in situ on Mars and others that will operate in the near future. The sample analyzed consisted of an oncoid, which is a type of microbialite, collected in the Salar Carachi Pampa, Argentina. The main peculiarity of microbialites is that they are organo-sedimentary deposits formed by the in situ fixation and precipitation of calcium carbonate due to the growth and metabolic activities of microorganisms.

Dark microbiome and extremely low organics in Atacama fossil delta unveil Mars life detection limits.

Identifying unequivocal signs of life on Mars is one of the most important objectives for sending missions to the red planet. Here we report Red Stone, a 163-100 My alluvial fan-fan delta that formed under arid conditions in the Atacama Desert, rich in hematite and mudstones containing clays such as vermiculite and smectites, and therefore geologically analogous to Mars. We show that Red Stone samples display an important number of microorganisms with an unusual high rate of phylogenetic indeterminacy, what we refer to as "dark microbiome", and a mix of biosignatures from extant and ancient microorganisms that can be barely detected with state-of-the-art laboratory equipment.

Organic geochemistry and mineralogy suggest anthropogenic impact in speleothem chemistry from volcanic show caves of the Galapagos.

The network of lava tubes is one of the most unexploited natural wonders of the Galapagos Islands. Here, we provide the first morphological, mineralogical, and biogeochemical assessment of speleothems from volcanic caves of the Galapagos to understand their structure, composition, and origin, as well as to identify organic molecules preserved in speleothems. Mineralogical analyses revealed that moonmilk and coralloid speleothems from Bellavista and Royal Palm Caves were composed of calcite, opal-A, and minor amounts of clay minerals.