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Press release embargoed by Nature Scientific Reports

until 10:00 AM (BST) Monday 27, May 2019

PRESS RELEASE

First nano-sized organisms found in the hottest region on Earth

An international scientific team led by the Centro de Astrobiología (CAB, CSIC-INTA) has discovered for the first time the presence of nano-sized microorganisms in the

multi-extreme conditions of the Dallol volcano, the hottest region on Earth, located in the Afar region, in Ethiopia. These microorganisms, which can survive and potentially live in one of the most extreme environments known, can be key to understand the

limits of habitability on both Earth and even on early Mars.

27-05-2019

The Dallol geothermal area in the northern part of the Danakil Depression (up to 124-155 meters below sea level) is deemed one of the most extreme environments on Earth. In fact, it is the hottest place on Earth. A new study, led by Felipe Gómez, researcher at the Centro de Astrobiología, and published in the journal Nature Scientific Reports, presents the first evidence of life found in this area. “Here, we describe for the first time morphological and molecular evidence of thermohaloacidophilic (loving high tempeature, high salt content and very low pH) nanomicroorganisms existing in this novel multi-extreme environment”, points out Gómez. Ultra-small structures are shown (which seems at the first look to be mineral precipitates) to be entombed within mineral deposits. In Gómez words, “Small (nano-sized) bacteria has been identified entombed in the salt layers deposited over the small chimneys in Dallol”. These organisms have been identified initially as members of the Order Nanohaloarchaea, although it could also be new microorganisms not described so far. This multi-extreme environment is located at the Afar Depression, an incipient seafloor spreading center located at the triple junction, between Nubian, Somali and Arabian Plates (it is characterized by an attenuated continental crust, which is less than 15 km thick with zones shallow 3–5 km deep magma chambers beneath its axial), and for hosting environments at the very edge of natural physical-chemical conditions. This is a narrow lowland salt plain (up to 124-155 meters below sea level) running inland, quasi-parallel to the Red Sea coast, which formed when part of the Red Sea was isolated during the Pleistocene. In the northern part of the area, a salt plain accumulation of marine evaporite deposits has been formed and host the Dallol volcano. The interaction between the evaporitic deposits and the volcanic activity have created the unique Dallol hot springs, which are highly acidic (pH zero or even negative) and saline (saturation) with maximum temperatures ranging between 90° and 109°C. At the surface, the water temperature at

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the source is above 100°C and highly acidic (pH ~ 0). The resultant hot pools vary in color depending on the high metal concentration (e.g. iron 35.6 g/l, copper 93 mg/l). A combination of these extreme chemical and physical parameters (e.g. temperature, pH, salinity and heavy metals) has resulted in a unique multi-extreme environment. The results from this study have deep implications for understanding the environmental limits of life and provides useful information for assessing the limits of habitability both on Earth and elsewhere in the Solar System, even on early Mars. Understanding, and defining these limits, using extreme terrestrial environments and Earth analogues sites is therefore a crucial step in selecting sites for future life detection missions.

About the CAB

The Center for Astrobiology (CAB) is a Joint Research Center of the Spanish National Research Council (CSIC) and the National Institute of Aerospace Technology (INTA). Created in 1999, it was the first Research Center of the world specifically devoted to astrobiological interdisciplinary research. In April 2000, CAB became the first Associate Member to NASA Astrobiology Institute (NAI). Its main objective is to study the origin, presence and influence of life in the universe. In addition to the understanding of the phenomenon of life as we know it (emergence, development, adaptability to extreme environments, etc.), it also involves the search for life beyond Earth (Exobiology) and Planetary Exploration and Habitability. Finally, the development of Advanced Space Technology and Instrumentation is also one of its main objectives. CAB is a truly multi-disciplinary institute, hosting scientists specializing in a very wide range of topics as Biology, Chemistry, Geology, Physics, Genetics, Ecology, Astrophysics, Planetology, Engineering, Mathematics, Computer Science, etc., and has also several Support Units, such as an Education & Public Outreach Office, an Administrative Unit, and an extensive scientific Library. Currently, CAB is hosting more than 120 researchers and technicians working on National and International Scientific Projects and participating in several European Networks. The CAB has developed the Rover Environmental Monitoring Station (REMS) for the mission Mars Science Laboratory (MSL), an environmental station on board NASA’s Curiosity rover, which is exploring Mars since 2012. Also, CAB has developed the Temperature and WINd Sensors (TWINS) instrument on board NASA’s InSight mission, that landed on the Red Planet in November 2018. Nowadays, there are two important developments going on: the Mars Environmental Dynamics Analyzer (MEDA) instrument for NASA’s Mars 2020 mission and the Raman Laser Spectrometer (RLS) instrument for ESA’s ExoMars 2020 mission. The CAB also participates in several instruments of great astrobiological relevance in development and/or operation, such as CARMENES, CHEOPS, PLATO, JWST/MIRI and JWST/NIRSPEC and BepiColombo/MIXS. The CAB has received in 2017 the distinction as María de Maeztu Unit by the Ministry of Science, Innovation and Universities, aimed at recognizing and promote Spanish Excellence in research.

Ctra. de Ajalvir km. 4, 28850 Torrejón de Ardoz, Madrid, España tel.: +34 91 5206433 fax: +34 91 5201074

More information

Figures

A) General view of the sampling site, (B) the small chimneys (temperature of water 90°C. (C) D9 sample from a small chimney in (A).

(D–L) SEM (Scanning Electron Microscopy) and (M–O) STEM (Scanning Transmission Electron Microscopy) images of sample D9 showing the morphologies of ultra-small microorganisms entombed in the mineral layers.

Ctra. de Ajalvir km. 4, 28850 Torrejón de Ardoz, Madrid, España tel.: +34 91 5206433 fax: +34 91 5201074

Scientific article in Nature Scientific Reports

“Ultra-small microorganisms in the polyextreme conditions of the Dallol volcano, Northern Afar, Ethiopia”, by F. Gómez, B. Cavalazzi, N. Rodríguez, R. Amils, G.G. Ori, K. Olsson-Francis, C. Escudero, J.M. Martínez & H. Miruts.

https://www.nature.com/articles/s41598-019-44440-8

Contact

Researcher at Centro de Astrobiología:

Felipe Gómez Gómez: gomezgf (+@cab.inta-csic.es)

EDUCATION AND PUBLIC OUTREACH DEPARTMENT

Paula Sánchez Narrillos: psanchez (+@cab.inta-csic.es); (+34) 915206438

Juan Ángel Vaquerizo: jvaquerizog (+@cab.inta-csic.es); (+34) 915201630