Advances in the Microbiology of the Atacama Desert and its Connection with Astrobiology Benito Gómez Silva Universidad de Antofagasta ASTROBIO SANTIAGO, CHILE

THE ATACAMA DESERT 1,200 km from approximately 18 o S to 28 o S located between the Pacific coast and the Andes Mountains the oldest and driest desert on Earth temperate hyperarid desert with mean annual temperature of 14–16 °C long term mean annual rainfall as low as 2 millimeters at its driest core increase in precipitation along the North-to-South latitude gradient became arid nearly 150 million years extreme aridity conditions for at least 10 – 15 million years ago large natural ore-grade nitrate deposits from atmospheric deposition, due to absence of soil leaching and biological cycling. Astrobiology 3, 393 (2003), Int. J. Climatol. 23, 1453 (2003), Geomorphology 73, 101 (2006), Microbiology of Extreme Soils. Soil Biology 13. P Dion, CS Nautiyal, eds. Springer, ASTROBIO SANTIAGO, CHILE

CONTRIBUTING FACTORS TO THE ATACAMA ARIDITY: (a) a zonal effect due to the subtropical high pressure belt which generates conditions for a strong precipitation deficit, (b) a continentality effect due to the distance of Atacama to the Amazonia-Atlantic moisture source, (c) a rainshadow effect due to the proximity of the Andes Range which prevents moisture advection from the east by disrupting zonal circulation, (in addition; “fog shadow” effect of the high coastal crest-line) (d) the oceanic effect carried out by the cold north-flowing Humboldt Current that upwells along the Atacama coast and generates a constant temperature inversion that traps moisture below 800 m altitude Astrobiology 3, 393 (2003), Int. J. Climatol. 23, 1453 (2003), Atmospheric Res. 71, 127 (2004) Microbiology of Extreme Soils. Soil Biology 13. P Dion, CS Nautiyal, eds. Springer, 2008., ASTROBIO SANTIAGO, CHILE

IS THERE MICROBIAL LIFE IN THE ATACAMA SOILS? If there is … What kind of microorganisms are at the Atacama? Abundance and diversity? Major environmental factor controlling life at the Atacama? ASTROBIO SANTIAGO, CHILE

“MARS-LIKE” SOILS AT THE HYPERARID CORE OF ATACAMA Very low levels of soil organic matter ( mg of C/g soil; 100 x lower than Dry Valleys soils, Antarctica) None or very low levels of detectable soil bacteria (by culture or DNA amplification) Soils contain a nonchirally specific oxidizing agent that equally oxidizes amino acid and glucose enantiomers. Science 302, 1018 (2003) ASTROBIO SANTIAGO, CHILE

EVIDENCE OF MICROBIAL LIFE IN THE ATACAMA SOILS: 1.Macroscopic and microscopic evidence: presence of microorganisms in hospitable habitats such as halites, quarzt, gypsum. 2.Biomarkers: soil organic matter (biomolecules) and biological, chemical, and photochemical decomposition mechanisms. 3.Microorganisms: culture dependent and independent methods Science 302, 1018 (2003), Microb. Ecol. 52, 389 (2006), Astrobiology 4, 415 (2006) J. Geophys. Res., 112, G04S15, doi: /2006JG (2007), J. Geophys. Res. 112, G02030, doi: /2006JG (2007), Proc. IV Int. Conference on Fog, Fog Collection and Dew, Santiago (2007), J. Geophys. Res. 113 doi: /2007JG (2008), J. Photochem. Photobiol.B: Biology 90, 79 (2008) ASTROBIO SANTIAGO, CHILE

1. SUITABLE NICHES FOR MICROBIAL COLONIZATION MUST BE: a. an intercepting obstacle for water droplets deposition from incoming fog events b.a surface for dew formation c.a temperature-controlling environment d.a filter to harmful solar UV radiation e.translucent to PAR (photosynthetic active radiation) J. Arid Environ. 65, 572 (2006) Astrobiology: Emergence, Search and Detection of Life. V.A. Basiuk, ed., American Scientific Publishers, In press. ASTROBIO SANTIAGO, CHILE

Microorganisms in hospitable habitats from Atacama: hypolithic growth in quartz. Astrobiology: Emergence, Search and Detection of Life. V.A. Basiuk, ed., American Scientific Publishers, In press. ASTROBIO SANTIAGO, CHILE

Microorganisms in hospitable habitats from Atacama: growth of epilithic (A) and endolithic (B) cyanobacterial biofilms in halites. Astrobiology: Emergence, Search and Detection of Life. V.A. Basiuk, ed., American Scientific Publishers, In press. ASTROBIO SANTIAGO, CHILE

Microorganisms in hospitable habitats from Atacama: epi-endolithic growth of melanized meristematic fungus in halites. Astrobiology: Emergence, Search and Detection of Life. V.A. Basiuk, ed., American Scientific Publishers, In press. ASTROBIO SANTIAGO, CHILE

Microorganisms in hospitable habitats from Atacama: gypsum ASTROBIO SANTIAGO, CHILE J. Geophys. Res. 112, G02030, doi: /2006JG (2007)

ASTROBIO SANTIAGO, CHILE ATACAMA SITEORGANICS DETECTEDMETHODREFERENCE 24°S, 70°W 28°S, 70°W Formic acid, benzene Formic acid, propenenitrile, benzene, ethylbenzene, 1, 2-dimethylbenzene, methylbenzene, benzenenitrile, 1,2-butadiene, 1,3-pentadiene, 2- methylfuran, styrene pyr-GC-MSScience 302, 1018 (2003) 24°-28°SAmino acids (gly, glu, asp, ala, ser; 10 – 500 ppb along the precipitation gradient)* HPLC (MOA) Proc. Nat. Acad. Sci. 102, 1041 (2005)* 27°SAmino acids (gly, ala, val; ng/g) GC-MSPlanet. Space Sci. 54, 1592 (2006) 2. SOIL ORGANIC MATTER (SOM) AND BIOMOLECULES * From the authors: “Results advance the technology for laboratory and field analyses of samples from and in Mars-like sites. Detection limits: parts per trillion.”

3. MICROORGANISMS IN ATACAMA SOILS Large numbers and diversity of bacterial life at sites where water is available but, are there any bacteria at the hyperarid soils of Atacama? Where? How abundant? How diverse? Heterotrophic bacteria are present in the surface and subsurface soils of the hyperarid Atacama Desert in an ecological pattern of non-uniform distribution or patchiness. Science 302, 1018 (2003), Appl. Environ. Microbiol. 70, 5923 (2004), Appl. Environ. Microbiol. 72, 7902 (2006) Soil Biol. Biochem. 39, 704 (2007), J. Geophys. Res. 112, G04S17, doi: /2006JG (2007) Int. J. Syst. Evol. Microbiol. 57, 1408 (2007), Microbiology of Extreme Soils. Soil Biology 13. P Dion, CS Nautiyal, eds. Springer, 2008., Astrobiology: Emergence, Search and Detection of Life. V.A. Basiuk, ed., American Scientific Publishers, In press. ASTROBIO SANTIAGO, CHILE

Atacama SitesDetectionCFU per gram of soilReferences 24° to 28°S, 70°W Viable counts <1 x 10 3 to  10 5 Science 302, 1018 (2003) 100 miles south of Yungay (24°04’S, 69°5’W) DAPI stain 0.7 x 10 6 (surface) 9.6 x 10 6 (subsurface) Appl. Environ. Microbiol. 70, 5923 (2004) 23°S, 70°W to 24°S, 69°W 400 to 4,500 masl Viable counts<1 x 10 3 to 10 7 Appl. Environ. Microbiol. 72, 7902 (2006) 24°S, 69°52’W Viable counts10 3 CFU/g Soil Biol. Biochem. 39, 704 (2007) ASTROBIO SANTIAGO, CHILE ABUNDANCE OF HETEROTROPHIC MICROORGANISMS FROM ATACAMA SOILS

ASTROBIO SANTIAGO, CHILE Phylogenetic LineagesReference Firmicutes Proteobacteria Actinobacteria Geodermatophilaceae Genera: Sphingomonas, Bacillus, Arthrobacter, Brevibacillus, Kocuria, Cellulomonas, Hymenobacter Science 302, 1018 (2003) Gemmatimonadetes, Planctomycetes, Actinobacteria, Thermomicrobia, Proteobacteria, Acidithiobacillus Appl. Environ. Microbiol. 72, 7902 (2006) Gemmatimonadetes, Actinobacteria, Planctomycetes, Thermomicrobia, Proteobacteria Soil Biol. Biochem. 39, 704 (2007) Proteobacteria, Firmicutes, uncultured MT7 phylum, Actinobacteria: Frankia J. Geophys. Res. 112, G04S17, doi: /2006JG (2007) DeinococcusInt. J. Syst. Evol. Microbiol. 57, 1408 (2007) DIVERSITY OF HETEROTROPHIC MICROORGANISMS FROM ATACAMA SOILS

ASTROBIO SANTIAGO, CHILE LIFE IN ATACAMA: THE CYANOBACTERIAL FACTOR

ASTROBIO SANTIAGO, CHILE CYANOBACTERIA Unicellular or filamentous Gram- negative photosynthetic prokaryotes Key primary producers in a variety of habitats, including hot and cold deserts; particularly, under water stress conditions too limiting for most eukaryotic or prokaryotic life forms Free-living microorganisms forming biofilms in lithobiontic niches Symbiotic association in lichens (phycobionts) Endolithic, epilithic, hypolithic colonization

ASTROBIO SANTIAGO, CHILE CYANOBACTERIA-DOMINATED MICROBIAL CONSORTIA IN ATACAMA QUARTZ STUDY AREA AT AGUAS CALIENTES (25°18’S)

ASTROBIO SANTIAGO, CHILE DIVERSITY OF PHOTOAUTOTROPHIC AND HETEROTROPHIC MICROORGANISMS FROM ATACAMA LITHOBIONTIC BIOFILMS LITHIC SUBSTRATEPHYLOGENETIC LINEAGESREFERENCE Quartz Chroococcidiopsis, Nostoc, Phormidium alpha-proteobacteria, gamma-proteobacteria acidobacteriales Microb. Ecol. 52, 389 (2006) Gypsum Cyanobacteriae, alphaproteobacteria Verrucomicrobia, Firmicutes, Bacillus, Gemmatimonadetes,Planctomycetes J. Geophys. Res. 112, G02030, doi: /2006JG (2007) Halites Chroococcidiopsis-like Heterotrophic bacteria Chroococcidiopsis Nectria sp. Astrobiology 4, 415 (2006) Astrobiology: Emergence, Search and Detection of Life. V.A. Basiuk, ed., Am Sci. Pub. In press.

ASTROBIO SANTIAGO, CHILE FACTOR WITH MINOR OR NULL IMPACT ON PHOTOAUTOTROPHIC LIFE AT ATACAMA HABITAT AVAILABILITY TEMPERATURE SOIL TOXICITY AND pH CARBON INFLOW MAJOR ABIOTIC FACTORS AFFECTING LITHOBIONTIC LIFE AT ATACAMA SUNLIGHT MOISTURE

ASTROBIO SANTIAGO, CHILE HABITAT AVAILABILITY (North-to-South transect) SITEYUNGAY 24°06’ AGUAS CALIENTES 25°18’ ALTAMIRA 25°45’ COPIAPÓ 27°01’ RELATIVE DISTANCE (Km) MEAN ANNUAL RAINFALL (mm) NUMBER OF STONES/m TOTAL STONES COUNTED % COLONIZED STONES Microb. Ecol. 52, 389 (2006)

ASTROBIO SANTIAGO, CHILE COLONIZED NICHESTEMPERATURE (°C) MaximumMinimum QUARTZ (coastal desert, 23°48’ S) AIR (17.2°C mean annual) STONE SURFACE BELOW THE STONE SOIL SURFACE SOIL (5 cm deep) QUARTZ (Yungay, desert core; 24°04’ S) AIR (16.5°C mean annual) STONE SURFACE QUARTZ (Aguas calientes, desert core; 25°18’ S) AIR (17.9°C mean annual) SOIL (2-5 cm deep) HALITES (Yungay, desert core, 24°49’ S) INSIDE THE CRUST OUTSIDE THE CRUST

ASTROBIO SANTIAGO, CHILE Location (70° W) Mean annual rainfall % of quartz stones with colonization 24° S2 mm0.1 25° S4 mm0.3 27° S21 mm28 LIQUID WATER AVAILABILITY FOR CYANOBACTERIAL QUARTZ COLONIZATION (NORTH-TO-SOUTH TRANSECT) Microb. Ecol. 52, 389 (2006) J. Geophys. Res., 112, G04S15, doi: /2006JG (2007) SOURCE OF LIQUID WATER RAIN FOG DEW

ASTROBIO SANTIAGO, CHILE DESSICATION TOLERANCE : biosynthesis of exopolysaccharides (EPS) EPS

ASTROBIO SANTIAGO, CHILE SOLAR AND UV RADIATION Annual average sunlight at the Atacama core: 335 Wm -2 Daily maximum over 1,000 Wm -2 Maximum values for PAR Yungay: 2.37 mmoles m -2 s -1 Salar Grande: 2.21 mmoles m -2 s -1 Quartz stones transmit from 0.08% to 1% of midday incident light (depending upon thickness and coloration). The lowest end of this intensity range is closer to or below the light compensation for photosynthesis of primary producers.

ASTROBIO SANTIAGO, CHILE J. Photochem. Photobiol. B: Biology 90, 79 (2008)

ASTROBIO SANTIAGO, CHILE MICROORGANISMS FROM ATACAMA STRATEGIES TO COPE WITH HIGH SOLAR UV RADIATION (UV-A: nm; UV-B: nm) PIGMENTABSORBANCE MAXIMA MAAs (mycosporine-like amino acids nm MELANIN in vivo: 335 nm in vitro: ; nm SCYTONEMIN* in vivo: 370 nm in vitro: 384 nm *only in cyanobacteria; aprox. 300 species.

ASTROBIO SANTIAGO, CHILE ABSOPTION SPECTRUM OF CRUDE EXTRACT FROM CYANOBACTERIAL BIOFILMS

ASTROBIO SANTIAGO, CHILE HPLC CHROMATOGRAM OF SCYTONEMIN FROM TWO CYANOBACTERIAL BIOFILMS

ASTROBIO SANTIAGO, CHILE ABSORPTION SPECTRUM OF SCYTONEMIN AFTER PURIFICATION BY HPLC

ASTROBIO SANTIAGO, CHILE HALITE COLONIZATIONPIGMENT CONTENT (mg g proteins -1 ) ScytoneminChlorophyll aCarotenoids EPILITHIC ENDOLITHIC EPIILITHIC COLONIZATIONENDOLITHIC COLONIZATION

ASTROBIO SANTIAGO, CHILE Héctor Olivares, Universidad de Antofagasta, Chile Catherine Lizama, Universidad de Antofagasta, Chile Armando Azua, PUC, Chile Jacek Wierzchos, CCMA – CSIC, Spain Carlos González, UNAP, Chile E. Imre Friedmann, NASA, USA Chris McKay, AMES – NASA, USA Alfonso F Dávila, NASA, USA Fred A Rainey, Louisiana State University, USA Rafael Navarro-González, UNAM, México Klaus Dose, Johannes Gutemberg-Universität, Mainz, Germany Sergio Risi, Johannes Gutemberg-Universität, Mainz, Germany

ASTROBIO SANTIAGO, CHILE Dr. E. Imre Friedmann An ”extreme” microbiologist Microbial ecology of absolute extreme environments, astrobiology, experimental and molecular taxonomy of cyanobacteria.