How Do Modern Extreme Hydrothermal Environments Inform the Identification of Martian Habitability? The Case of the El Tatio Geyser Field

Roberto Barbieri,Barbara Cavalazzi

doi:10.3390/challe5020430

Abstract

Despite the success in knowledge gained by the Mars missions in the last two decades, the search for traces of life on Mars is still in progress. The reconstruction of (paleo-) environments on Mars have seen a dramatic increase, in particular with regard to the potentially habitable conditions, and it is now possible to recognize a significant role to subaerial hydrothermal processes. For this reason, and because the conditions of the primordial Earth—when these extreme environments had to be common—probably resembled Mars during its most suitable time to host life, research on terrestrial extreme hydrothermal habitats may assist in understanding how to recognize life on Mars. A number of geological and environmental reasons, and logistics opportunities, make the geothermal field of El Tatio, in the Chilean Andes an ideal location to study.

Highlights

Since the pioneering work by Brock at the Yellowstone National Park [1], the identification of hyperthermophilic microorganisms has opened an extraordinary field for the study of the early evolution
Hydrothermalism depends on volcanic activities on land, in the seafloor, and in the deep subsurface, and provides habitats for chemosynthetic,thermophilic microbial life forms in the deep systems, while at the surface they are active competitors of photosynthetic ones
A typical case is that of the desiccation-tolerant and radiation-resistant coccoid Chroococcidiopsis, one of the most primitive cyanobacteria, which is able to live in a wide range of extremely severe conditions (e.g., [52,53,54]), including hot springs, and was proposed as a pioneer microorganism for terraforming Mars [55]

Summary

Introduction

Since the pioneering work by Brock at the Yellowstone National Park [1], the identification of hyperthermophilic microorganisms has opened an extraordinary field for the study of the early evolution. Whereas in the seafloor the geothermal areas are usually close to an oceanic ridge, on land they are associated with different types of volcanic emissions In both cases, the resulting hydrothermal systems depend on the heating and the emission of water at high temperatures. The resulting hydrothermal systems depend on the heating and the emission of water at high temperatures Because this combination of liquid water and energy sources is considered necessary for life outside of the Earth, hydrothermal environments detected on Mars are among the most promising targets for searching for traces of possible extraterrestrial life. Similar to their terrestrial analogues, an important aspect of these Martian subaerial hydrothermal deposits, which could contribute to the reconstruction of the planet’s evolution over time, is that they could convey information on hydrothermal fluid flow circulation of the deep subsurface (that cannot yet be achieved) up to the planet’s surface

Hydrothermalism

Los Géiseres del Tatio

Conclusions