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Finkel PL, Carrizo D, Rasmussen KR, Knudsen NAT, Parro V, Sánchez-García L. Lipid-based paleoecological and biogeochemical reconstruction of Store Saltsø, an extreme lacustrine system in SW Greenland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171199. [PMID: 38408664 DOI: 10.1016/j.scitotenv.2024.171199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/07/2024] [Accepted: 02/21/2024] [Indexed: 02/28/2024]
Abstract
Polar lakes harbour a unique biogeochemistry that reflects the implications of climatic fluctuations against a susceptible yet extreme environment. In addition to polar, Store Saltsø (Kangerlussuaq, southwestern Greenland) is an endorheic lake with alkaline and oligotrophic waters that host a distinctive ecology adapted to live in such particular physico-chemical and environmental conditions. By exploring the sedimentary record of Store Saltsø at a molecular and compound-specific isotopic level, we were able to understand its ecology and biogeochemical evolution upon climate change. We employed lipid biomarkers to identify biological sources and metabolic traits in different environmental samples (shore terrace, sediment core, and white precipitates at the shore), and their succession over time to reconstruct the lake paleobiology. Different molecular ratios and geochemical proxies provided further insights toward the evolution of environmental conditions in the frame of the deglaciation history of Kangerlussuaq. The relative abundance of terrestrial (i.e., plant derived) biomarkers (odd long-chain n-alkanes, even long-chain n-alkanols, and phytosterols) in the upper half of the shore terrace versus the relatively more present aquatic biomarkers (botryococcenes and long-chain alkenones) in its lower half revealed higher lake water levels in the past. Moreover, the virtual absence of organics in the deepest section of the sediment core (32-29 cm depth) suggested that the lake did not yet exist at the northwestern shore of Store Saltsø ∼5100 years ago. According to the relative abundance of lipid biomarkers detected in the adjacent section above (29-25 cm depth), we hypothesize that the northwestern shore of Store Saltsø formed ∼4900 years ago. By combining the molecular and compound-specific isotopic analysis of lipids in a ∼360 cm sedimentary sequence, we recreated the paleobiology and evolution of an extreme lacustrine environment suitable for the study of the limits of life and the effects of climate warming.
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Affiliation(s)
- Pablo L Finkel
- Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain; Department of Physics and Mathematics, Department of Automatics, University of Alcalá, Madrid, Spain
| | | | | | | | - Victor Parro
- Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain
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Sánchez-García L, Carrizo D, Jiménez-Gavilán P, Ojeda L, Parro V, Vadillo I. Serpentinization-associated travertines as spatio-temporal archives for lipid biomarkers key for the search for life on Mars. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169045. [PMID: 38061658 DOI: 10.1016/j.scitotenv.2023.169045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 01/18/2024]
Abstract
Serpentinization is a well-known aqueous alteration process that may have played important roles in the origins and early evolution of life on Earth, and perhaps Mars, but there are still aspects related to biomarker distribution, partitioning, and preservation that merit further study. To assess the role that precipitation of carbonate phases in serpentinization settings may have on biomarker preservation, we search for life signs in one of the world's largest outcrops of subcontinental peridotites (Ronda, South Spain). We investigate the organic record of groundwater and associated carbonate deposits (travertines) in seven hyperalkaline springs, and reconstruct the biological activity and metabolic interactions of the serpentinization-hosted ecosystem. We identified lipid biomarkers and isotopic evidences of life, whose concentration and variety were much lower in groundwater than travertine deposits (ppb/ppt versus ppm level). Groundwater carried organics of abiotic (n-alkanes with values of CPI ∼ 1) and/or biotic origin, of fresher (e.g. acids or alcohols) or more diagenetized (mature hopanes and n-alkanes) nature. In contrast, associated travertines held a more prolific record of biomarkers incorporating (molecular and isotopic) fingerprints of surface (mostly phototrophs) and subsurface (chemolithotrophs, methanogens and/or methanotrophs) life. Serpentinization-associated travertines seem to act as biomolecule archives over time fed by autochthonous and allochthonous sources, hence amplifying the dim biological signal of groundwater. These results illustrate the relevance of serpentinization-associated surface mineral deposits in searching for traces of life on analogous environments on Mars. We highlight the diversity of lipids produced in serpentinizing land environments and emphasize the potential of these geostable biomolecules to preserve fingerprints of life.
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Affiliation(s)
- Laura Sánchez-García
- Centro de Astrobiología (CAB, CSIC-INTA), 28850 - Torrejón de Ardoz, Madrid, Spain.
| | - Daniel Carrizo
- Centro de Astrobiología (CAB, CSIC-INTA), 28850 - Torrejón de Ardoz, Madrid, Spain
| | - Pablo Jiménez-Gavilán
- Department of Geology, Faculty of Science, University of Malaga, 29071 Málaga, Spain
| | - Lucía Ojeda
- Department of Geology, Faculty of Science, University of Malaga, 29071 Málaga, Spain
| | - Víctor Parro
- Centro de Astrobiología (CAB, CSIC-INTA), 28850 - Torrejón de Ardoz, Madrid, Spain
| | - Iñaki Vadillo
- Department of Geology, Faculty of Science, University of Malaga, 29071 Málaga, Spain
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3
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Sánchez-García L, Lezcano MÁ, Carrizo D, Severino R, García-Villadangos M, Cady SL, Warren-Rhodes K, Cabrol NA, Parro V. Assessing siliceous sinter matrices for long-term preservation of lipid biomarkers in opaline sinter deposits analogous to Mars in El Tatio (Chile). THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:161765. [PMID: 36702265 DOI: 10.1016/j.scitotenv.2023.161765] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Subaerial hydrothermal systems are of great interest for paleobiology and astrobiology as plausible candidate environments to support the origin of life on Earth that offer a unique and interrelated atmosphere-hydrosphere-lithosphere interface. They harbor extensive sinter deposits of high preservation potential that are promising targets in the search for traces of possible extraterrestrial life on Hesperian Mars. However, long-term quality preservation is paramount for recognizing biosignatures in old samples and there are still significant gaps in our understanding of the impact and extent of taphonomy processes on life fingerprints. Here, we propose a study based on lipid biomarkers -highly resistant cell-membrane components- to investigate the effects of silicification on their preservation in hydrothermal opaline sinter. We explore the lipid biomarkers profile in three sinter deposits of up to ~3000 years from El Tatio, one of the best Martian analogs on Earth. The lipid profile in local living biofilms is used as a fresh counterpart of the fossil biomarkers in the centuries-old sinter deposits to qualitatively assess the taphonomy effects of silicification on the lipid's preservation. Despite the geological alteration, the preserved lipids retained a depleted stable-carbon isotopic fingerprint characteristic of biological sources, result highly relevant for astrobiology. The data allowed us to estimate for the first time the degradation rate of lipid biomarkers in sinter deposits from El Tatio, and to assess the time preservation framework of opaline silica. Auxiliary techniques of higher taxonomic resolution (DNA sequencing and metaproteomics) helped in the reconstruction of the paleobiology. The lipids were the best-preserved biomolecules, whereas the detection of DNA and proteins dropped considerably from 5 cm depth. These findings provide new insights into taphonomy processes affecting life fingerprints in hydrothermal deposits and serves as a useful baseline for assessing the time window for recovering unambiguous signs of past life on Earth and beyond.
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Affiliation(s)
| | | | - Daniel Carrizo
- Centro de Astrobiología (CAB, CSIC-INTA), 28850 Torrejón de Ardoz, Spain
| | - Rita Severino
- Centro de Astrobiología (CAB, CSIC-INTA), 28850 Torrejón de Ardoz, Spain; Dept. of Physics and Mathematics and Automatics, University of Alcalá (UAH), 28805 Alcalá de Henares, Spain
| | | | - Sherry L Cady
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Kim Warren-Rhodes
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, CA 94043, United States
| | - Nathalie A Cabrol
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, CA 94043, United States
| | - Víctor Parro
- Centro de Astrobiología (CAB, CSIC-INTA), 28850 Torrejón de Ardoz, Spain
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Severino R, Moreno-Paz M, Puente-Sánchez F, Sánchez-García L, Risso VA, Sanchez-Ruiz JM, Cabrol N, Parro V. Immunoanalytical Approach for Detecting and Identifying Ancestral Peptide Biomarkers in Early Earth Analogue Environments. Anal Chem 2023; 95:5323-5330. [PMID: 36926836 PMCID: PMC10061368 DOI: 10.1021/acs.analchem.2c05386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Several mass spectrometry and spectroscopic techniques have been used in the search for molecular biomarkers on Mars. A major constraint is their capability to detect and identify large and complex compounds such as peptides or other biopolymers. Multiplex immunoassays can detect these compounds, but antibodies must be produced for a large number of sequence-dependent molecular targets. Ancestral Sequence Reconstruction (ASR) followed by protein "resurrection" in the lab can help to narrow the selection of targets. Herein, we propose an immunoanalytical method to identify ancient and universally conserved protein/peptide sequences as targets for identifying ancestral biomarkers in nature. We have developed, tested, and validated this approach by producing antibodies to eight previously described ancestral resurrected proteins (three β-lactamases, three thioredoxins, one Elongation Factor Tu, and one RuBisCO, all of them theoretically dated as Precambrian), and used them as a proxy to search for any potential feature of them that could be present in current natural environments. By fluorescent sandwich microarray immunoassays (FSMI), we have detected positive immunoreactions with antibodies to the oldest β-lactamase and thioredoxin proteins (ca. 4 Ga) in samples from a hydrothermal environment. Fine epitope mapping and inhibitory immunoassays allowed the identification of well-conserved epitope peptide sequences that resulted from ASR and were present in the sample. We corroborated these results by metagenomic sequencing and found several genes encoding analogue proteins with significant matches to the peptide epitopes identified with the antibodies. The results demonstrated that peptides inferred from ASR studies have true counterpart analogues in Nature, which validates and strengthens the well-known ASR/protein resurrection technique and our immunoanalytical approach for investigating ancient environments and metabolisms on Earth and elsewhere.
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Affiliation(s)
- Rita Severino
- Centro de Astrobiología (CAB), CSIC-INTA, 28850 Torrejón de Ardoz, Madrid, Spain.,PhD Program in Space Research and Astrobiology, University of Alcalá (UAH), 28805 Alcalá de Henares, Madrid, Spain
| | - Mercedes Moreno-Paz
- Centro de Astrobiología (CAB), CSIC-INTA, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Fernando Puente-Sánchez
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), 75651 Uppsala, Sweden
| | - Laura Sánchez-García
- Centro de Astrobiología (CAB), CSIC-INTA, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Valeria A Risso
- Departamento de Química Física, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071 Granada, Spain
| | - Jose M Sanchez-Ruiz
- Departamento de Química Física, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071 Granada, Spain
| | - Nathalie Cabrol
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, Mountain View, California 94043, United States
| | - Victor Parro
- Centro de Astrobiología (CAB), CSIC-INTA, 28850 Torrejón de Ardoz, Madrid, Spain
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Finkel PL, Carrizo D, Parro V, Sánchez-García L. An Overview of Lipid Biomarkers in Terrestrial Extreme Environments with Relevance for Mars Exploration. ASTROBIOLOGY 2023; 23:563-604. [PMID: 36880883 PMCID: PMC10150655 DOI: 10.1089/ast.2022.0083] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Lipid molecules are organic compounds, insoluble in water, and based on carbon-carbon chains that form an integral part of biological cell membranes. As such, lipids are ubiquitous in life on Earth, which is why they are considered useful biomarkers for life detection in terrestrial environments. These molecules display effective membrane-forming properties even under geochemically hostile conditions that challenge most of microbial life, which grants lipids a universal biomarker character suitable for life detection beyond Earth, where a putative biological membrane would also be required. What discriminates lipids from nucleic acids or proteins is their capacity to retain diagnostic information about their biological source in their recalcitrant hydrocarbon skeletons for thousands of millions of years, which is indispensable in the field of astrobiology given the time span that the geological ages of planetary bodies encompass. This work gathers studies that have employed lipid biomarker approaches for paleoenvironmental surveys and life detection purposes in terrestrial environments with extreme conditions: hydrothermal, hyperarid, hypersaline, and highly acidic, among others; all of which are analogous to current or past conditions on Mars. Although some of the compounds discussed in this review may be abiotically synthesized, we focus on those with a biological origin, namely lipid biomarkers. Therefore, along with appropriate complementary techniques such as bulk and compound-specific stable carbon isotope analysis, this work recapitulates and reevaluates the potential of lipid biomarkers as an additional, powerful tool to interrogate whether there is life on Mars, or if there ever was.
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Affiliation(s)
- Pablo L Finkel
- Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain
- Department of Physics and Mathematics and Department of Automatics, University of Alcalá, Madrid, Spain
| | | | - Victor Parro
- Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain
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Azua-Bustos A, Fairén AG, González-Silva C, Prieto-Ballesteros O, Carrizo D, Sánchez-García L, Parro V, Fernández-Martínez MÁ, Escudero C, Muñoz-Iglesias V, Fernández-Sampedro M, Molina A, Villadangos MG, Moreno-Paz M, Wierzchos J, Ascaso C, Fornaro T, Brucato JR, Poggiali G, Manrique JA, Veneranda M, López-Reyes G, Sanz-Arranz A, Rull F, Ollila AM, Wiens RC, Reyes-Newell A, Clegg SM, Millan M, Johnson SS, McIntosh O, Szopa C, Freissinet C, Sekine Y, Fukushi K, Morida K, Inoue K, Sakuma H, Rampe E. Dark microbiome and extremely low organics in Atacama fossil delta unveil Mars life detection limits. Nat Commun 2023; 14:808. [PMID: 36810853 PMCID: PMC9944251 DOI: 10.1038/s41467-023-36172-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 01/17/2023] [Indexed: 02/24/2023] Open
Abstract
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. Our analyses by testbed instruments that are on or will be sent to Mars unveil that although the mineralogy of Red Stone matches that detected by ground-based instruments on the red planet, similarly low levels of organics will be hard, if not impossible to detect in Martian rocks depending on the instrument and technique used. Our results stress the importance in returning samples to Earth for conclusively addressing whether life ever existed on Mars.
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Affiliation(s)
- Armando Azua-Bustos
- Centro de Astrobiología (CAB) (CSIC-INTA), 28850, Madrid, Spain. .,Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile.
| | - Alberto G Fairén
- Centro de Astrobiología (CAB) (CSIC-INTA), 28850, Madrid, Spain.,Department of Astronomy, Cornell University, Ithaca, 14853, NY, USA
| | | | | | - Daniel Carrizo
- Centro de Astrobiología (CAB) (CSIC-INTA), 28850, Madrid, Spain
| | | | - Victor Parro
- Centro de Astrobiología (CAB) (CSIC-INTA), 28850, Madrid, Spain
| | | | | | | | | | - Antonio Molina
- Centro de Astrobiología (CAB) (CSIC-INTA), 28850, Madrid, Spain
| | | | | | - Jacek Wierzchos
- Museo Nacional de Ciencias Naturales (CSIC), 28006, Madrid, Spain
| | - Carmen Ascaso
- Museo Nacional de Ciencias Naturales (CSIC), 28006, Madrid, Spain
| | - Teresa Fornaro
- INAF-Astrophysical Observatory of Arcetri, Florence, Italy
| | | | | | - Jose Antonio Manrique
- Universidad de Valladolid, Valladolid, Spain.,Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France
| | | | | | | | | | - Ann M Ollila
- Purdue University, Earth, Atmospheric, and Planetary Sciences, West Lafayette, USA
| | - Roger C Wiens
- Purdue University, Earth, Atmospheric, and Planetary Sciences, West Lafayette, USA
| | | | - Samuel M Clegg
- Purdue University, Earth, Atmospheric, and Planetary Sciences, West Lafayette, USA
| | - Maëva Millan
- Department of Biology, Georgetown University, Washington, DC, 20057, USA.,NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, 20771, USA.,LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, 11 Bd d'Alembert, 78280, Guyancourt, France
| | - Sarah Stewart Johnson
- Department of Biology, Georgetown University, Washington, DC, 20057, USA.,Science, Technology, and International Affairs Program, Georgetown University, Washington, DC, 20057, USA
| | - Ophélie McIntosh
- INAF-Astrophysical Observatory of Arcetri, Florence, Italy.,Science, Technology, and International Affairs Program, Georgetown University, Washington, DC, 20057, USA
| | - Cyril Szopa
- Science, Technology, and International Affairs Program, Georgetown University, Washington, DC, 20057, USA
| | - Caroline Freissinet
- Science, Technology, and International Affairs Program, Georgetown University, Washington, DC, 20057, USA
| | - Yasuhito Sekine
- Earth-Life Science Institute (ELSI), Tokyo Institute of Technology, Tokyo, Japan.,Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, Japan
| | - Keisuke Fukushi
- Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, Japan
| | - Koki Morida
- Division of Natural System, Kanazawa University, Kanazawa, Japan
| | - Kosuke Inoue
- Division of Natural System, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Sakuma
- National Institute for Materials Science, Tsukuba, Japan
| | - Elizabeth Rampe
- Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX, USA
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Fairén AG, Rodríguez N, Sánchez-García L, Rojas P, Uceda ER, Carrizo D, Amils R, Sanz JL. Ecological successions throughout the desiccation of Tirez lagoon (Spain) as an astrobiological time-analog for wet-to-dry transitions on Mars. Sci Rep 2023; 13:1423. [PMID: 36755119 PMCID: PMC9908944 DOI: 10.1038/s41598-023-28327-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 01/17/2023] [Indexed: 02/10/2023] Open
Abstract
Tirez was a small and seasonal endorheic athalassohaline lagoon that was located in central Spain. In recent years, the lagoon has totally dried out, offering for the first time the opportunity to analyze its desiccation process as a "time-analog" to similar events occurred in paleolakes with varying salinity during the wet-to-dry transition on early Mars. On the martian cratered highlands, an early period of water ponding within enclosed basins evolved to a complete desiccation of the lakes, leading to deposition of evaporitic sequences during the Noachian and into the Late Hesperian. As Tirez also underwent a process of desiccation, here we describe (i) the microbial ecology of Tirez when the lagoon was still active 20 years ago, with prokaryotes adapted to extreme saline conditions; (ii) the composition of the microbial community in the dried lake sediments today, in many case groups that thrive in sediments of extreme environments; and (iii) the molecular and isotopic analysis of the lipid biomarkers that can be recovered from the sediments today. We discuss the implications of these results to better understanding the ecology of possible Martian microbial communities during the wet-to-dry transition at the end of the Hesperian, and how they may inform about research strategies to search for possible biomarkers in Mars after all the water was lost.
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Affiliation(s)
- Alberto G Fairén
- Centro de Astrobiología (CSIC-INTA), 28850, Torrejón de Ardoz, Spain. .,Department of Astronomy, Cornell University, Ithaca, NY, 14853, USA.
| | - Nuria Rodríguez
- Centro de Astrobiología (CSIC-INTA), 28850, Torrejón de Ardoz, Spain.,Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | | | - Patricia Rojas
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Esther R Uceda
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Daniel Carrizo
- Centro de Astrobiología (CSIC-INTA), 28850, Torrejón de Ardoz, Spain
| | - Ricardo Amils
- Centro de Astrobiología (CSIC-INTA), 28850, Torrejón de Ardoz, Spain.,Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain.,Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - José L Sanz
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain.
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Megevand V, Carrizo D, Lezcano MÁ, Moreno-Paz M, Cabrol NA, Parro V, Sánchez-García L. Lipid Profiles From Fresh Biofilms Along a Temperature Gradient on a Hydrothermal Stream at El Tatio (Chilean Andes), as a Proxy for the Interpretation of Past and Present Biomarkers Beyond Earth. Front Microbiol 2022; 13:811904. [PMID: 35832812 PMCID: PMC9271869 DOI: 10.3389/fmicb.2022.811904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Hydrothermal systems and their deposits are primary targets in the search for fossil evidence of life beyond Earth. However, to learn how to decode fossil biomarker records in ancient hydrothermal deposits, we must first be able to interpret unambiguously modern biosignatures, their distribution patterns, and their association with physicochemical factors. Here, we investigated the molecular and isotopic profile of microbial biomarkers along a thermal gradient (from 29 to 72°C) in a hot spring (labeled Cacao) from El Tatio, a geyser field in the Chilean Andes with abundant opaline silica deposits resembling the nodular and digitate structures discovered on Mars. As a molecular forensic approach, we focused on the analysis of lipid compounds bearing recognized resistance to degradation and the potential to reconstruct the paleobiology of an environment on a broader temporal scale than other, more labile, biomolecules. By exploiting the lipid biomarkers’ potential to diagnose biological sources and carbon fixation pathways, we reconstructed the microbial community structure and its ecology along the Cacao hydrothermal transect. The taxonomic adscription of the lipid biomarkers was qualitatively corroborated with DNA sequencing analysis. The forensic capacity of the lipid biomarkers to identify biosources in fresh biofilms was validated down to the genus level for Roseiflexus, Chloroflexus, and Fischerella. We identified lipid biomarkers and DNA of several new cyanobacterial species in El Tatio and reported the first detection of Fischerella biomarkers at a temperature as high as 72°C. This, together with ecological peculiarities and the proportion of clades being characterized as unclassified, illustrates the ecological singularity of El Tatio and strengthens its astrobiological relevance. The Cacao hydrothermal ecosystem was defined by a succession of microbial communities and metabolic traits associated with a high- (72°C) to low-(29°C) temperature gradient that resembled the inferred metabolic sequence events from the 16S rRNA gene universal phylogenetic tree from thermophilic to anoxygenic photosynthetic species and oxygenic phototrophs. The locally calibrated DNA-validated lipidic profile in the Cacao biofilms provided a modern (molecular and isotopic) end member to facilitate the recognition of past biosources and metabolisms from altered biomarkers records in ancient silica deposits at El Tatio analogous to Martian opaline silica structures.
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Affiliation(s)
- Valentine Megevand
- Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
- Department of Earth Sciences, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon, Lyon, France
| | | | | | | | - Nathalie A. Cabrol
- Carl Sagan Center for Research, The SETI Institute, Mountain View, CA, United States
| | - Víctor Parro
- Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
| | - Laura Sánchez-García
- Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
- *Correspondence: Laura Sánchez-García,
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9
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Lezcano MÁ, Sánchez-García L, Quesada A, Carrizo D, Fernández-Martínez MÁ, Cavalcante-Silva E, Parro V. Comprehensive Metabolic and Taxonomic Reconstruction of an Ancient Microbial Mat From the McMurdo Ice Shelf (Antarctica) by Integrating Genetic, Metaproteomic and Lipid Biomarker Analyses. Front Microbiol 2022; 13:799360. [PMID: 35928160 PMCID: PMC9345047 DOI: 10.3389/fmicb.2022.799360] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 03/21/2022] [Indexed: 12/31/2022] Open
Abstract
Paleobiological reconstructions based on molecular fossils may be limited by degradation processes causing differential preservation of biomolecules, the distinct taxonomic specificity of each biomolecule type, and analytical biases. Here, we combined the analysis of DNA, proteins and lipid biomarkers using 16S and 18S rRNA gene metabarcoding, metaproteomics and lipid analysis to reconstruct the taxonomic composition and metabolisms of a desiccated microbial mat from the McMurdo Ice Shelf (MIS) (Antarctica) dated ~1,000 years BP. The different lability, taxonomic resolution and analytical bias of each biomolecule type led to a distinct microbial community profile. DNA analysis showed selective preservation of DNA remnants from the most resistant taxa (e.g., spore-formers). In contrast, the proteins profile revealed microorganisms missed by DNA sequencing, such as Cyanobacteria, and showed a microbial composition similar to fresh microbial mats in the MIS. Lipid hydrocarbons also confirmed Cyanobacteria and suggested the presence of mosses or vascular plant remnants from a period in Antarctica when the climate was warmer (e.g., Mid-Miocene or Eocene). The combined analysis of the three biomolecule types also revealed diverse metabolisms that operated in the microbial mat before desiccation: oxygenic and anoxygenic photosynthesis, nitrogen fixation, nitrification, denitrification, sulfur reduction and oxidation, and methanogenesis. Therefore, the joint analysis of DNA, proteins and lipids resulted in a powerful approach that improved taxonomic and metabolic reconstructions overcoming information gaps derived from using individual biomolecules types.
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Affiliation(s)
- María Ángeles Lezcano
- Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir, Madrid, Spain
- *Correspondence: María Ángeles Lezcano,
| | | | - Antonio Quesada
- Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir, Madrid, Spain
- Departamento de Biología, C. Darwin 2, Universidad Autónoma de Madrid, Madrid, Spain
| | - Daniel Carrizo
- Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir, Madrid, Spain
| | | | | | - Víctor Parro
- Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir, Madrid, Spain
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