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Publications (10 of 35) Show all publications
Siljeström, S., Thiel, V. & Steele, A. (2019). Preservation of heme derivatives in vertebrate fossils from the Messel Pit and Enspel, Germany. In: 29th International Meeting on Organic Geochemistry, IMOG 2019: . Paper presented at 29th International Meeting on Organic Geochemistry, IMOG 2019, 1 September 2019 through 6 September 2019. European Association of Geoscientists and Engineers, EAGE
Open this publication in new window or tab >>Preservation of heme derivatives in vertebrate fossils from the Messel Pit and Enspel, Germany
2019 (English)In: 29th International Meeting on Organic Geochemistry, IMOG 2019, European Association of Geoscientists and Engineers, EAGE , 2019Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
European Association of Geoscientists and Engineers, EAGE, 2019
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40880 (URN)2-s2.0-85074252213 (Scopus ID)9789462823044 (ISBN)
Conference
29th International Meeting on Organic Geochemistry, IMOG 2019, 1 September 2019 through 6 September 2019
Available from: 2019-12-10 Created: 2019-12-10 Last updated: 2019-12-10Bibliographically approved
Drake, H., Roberts, N., Heim, C., Whitehouse, M., Siljeström, S., Kooijman, E., . . . Åström, M. (2019). Timing and origin of natural gas accumulation in the Siljan impact structure, Sweden. Nature Communications, 10(1), Article ID 4736.
Open this publication in new window or tab >>Timing and origin of natural gas accumulation in the Siljan impact structure, Sweden
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2019 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, no 1, article id 4736Article in journal (Refereed) Published
Abstract [en]

Fractured rocks of impact craters may be suitable hosts for deep microbial communities on Earth and potentially other terrestrial planets, yet direct evidence remains elusive. Here, we present a study of the largest crater of Europe, the Devonian Siljan structure, showing that impact structures can be important unexplored hosts for long-term deep microbial activity. Secondary carbonate minerals dated to 80 ± 5 to 22 ± 3 million years, and thus postdating the impact by more than 300 million years, have isotopic signatures revealing both microbial methanogenesis and anaerobic oxidation of methane in the bedrock. Hydrocarbons mobilized from matured shale source rocks were utilized by subsurface microorganisms, leading to accumulation of microbial methane mixed with a thermogenic and possibly a minor abiotic gas fraction beneath a sedimentary cap rock at the crater rim. These new insights into crater hosted gas accumulation and microbial activity have implications for understanding the astrobiological consequences of impacts. © 2019, The Author(s).

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
Keywords
abiotic factor, anaerobic digestion, bedrock, cap rock, crater, Devonian, methane, methanogenesis, microbial activity, oxidation, shale, Dalarna, Siljan, Sweden
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40597 (URN)10.1038/s41467-019-12728-y (DOI)2-s2.0-85073546979 (Scopus ID)
Note

Funding details: Vetenskapsrådet, VR, 04129, 2017–05186, 2017–00766; Funding text 1: Thanks to AB Igrene for access to drill cores, drilling logs and gas data. Swedish research council (contract 2017–05186 to H.D., 2015–04129 to S.S., 2017–04129 to M.I.) and Formas (contract 2017–00766 to H.D. and M.W.) are thanked for financial support. K. Lindén, M. Tillberg, and M. Schmitt are thanked for analytical or sample preparation assistance, and University of Gothenburg for access to SEM. This is NordSIM publication 617 and Vegacenter publication 20.

Available from: 2019-11-12 Created: 2019-11-12 Last updated: 2019-11-12Bibliographically approved
Ivarsson, M., Skogby, H., Phichaikamjornwut, B., Bengtson, S., Siljeström, S., Ounchanum, P., . . . Holmström, S. (2018). Intricate tunnels in garnets from soils and river sediments in Thailand - Possible endolithic microborings. PLoS ONE, 13(8), Article ID e0200351.
Open this publication in new window or tab >>Intricate tunnels in garnets from soils and river sediments in Thailand - Possible endolithic microborings
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2018 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 8, article id e0200351Article in journal (Refereed) Published
Abstract [en]

Garnets from disparate geographical environments and origins such as oxidized soils and river sediments in Thailand host intricate systems of microsized tunnels that significantly decrease the quality and value of the garnets as gems. The origin of such tunneling has previously been attributed to abiotic processes. Here we present physical and chemical remains of endolithic microorganisms within the tunnels and discuss a probable biological origin of the tunnels. Extensive investigations with synchrotron-radiation X-ray tomographic microscopy (SRXTM) reveal morphological indications of biogenicity that further support a euendolithic interpretation. We suggest that the production of the tunnels was initiated by a combination of abiotic and biological processes, and that at later stages biological processes came to dominate. In environments such as river sediments and oxidized soils garnets are among the few remaining sources of bio-available Fe2+, thus it is likely that microbially mediated boring of the garnets has trophic reasons. Whatever the reason for garnet boring, the tunnel system represents a new endolithic habitat in a hard silicate mineral otherwise known to be resistant to abrasion and chemical attack.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35146 (URN)10.1371/journal.pone.0200351 (DOI)30089115 (PubMedID)2-s2.0-85051426408 (Scopus ID)
Note

 The authors acknowledge funding from the Swedish Research Council (Contracts No. 2007-4483 (SB), 2010-3929 (HS), 2012-4364 (MI), and 2013-4290 (SB), 2015-04129 (SS)), Danish National Research Foundation (DNRF53), and Paul Scherrer Institute (20130185) (MI) as well as Swedish National Space Board (Contract No. 83/10 (MI), 121/11 and 198/15 (SS)).

Available from: 2018-09-10 Created: 2018-09-10 Last updated: 2019-01-09Bibliographically approved
Steele, A., Benning, L. G., Wirth, R., Siljeström, S., Fries, M. D., Hauri, E., . . . Rodriguez Blanco, J. D. (2018). Organic synthesis on Mars by electrochemical reduction of CO<sub>2</sub>. Science Advances, 4(10), Article ID eaat5118.
Open this publication in new window or tab >>Organic synthesis on Mars by electrochemical reduction of CO<sub>2</sub>
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2018 (English)In: Science Advances, Vol. 4, no 10, article id eaat5118Article in journal (Refereed) Published
Abstract [en]

The sources and nature of organic carbon on Mars have been a subject of intense research. Steele et al. (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted melt inclusions. Here, we show that martian meteorites Tissint, Nakhla, and NWA 1950 have an inventory of organic carbon species associated with fluid-mineral reactions that are remarkably consistent with those detected by the Mars Science Laboratory (MSL) mission. We advance the hypothesis that interactions among spinel-group minerals, sulfides, and a brine enable the electrochemical reduction of aqueous CO2 to organic molecules. Although documented here in martian samples, a similar process likely occurs wherever igneous rocks containing spinel-group minerals and/or sulfides encounter brines.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36375 (URN)10.1126/sciadv.aat5118 (DOI)2-s2.0-85055869978 (Scopus ID)
Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-01-10Bibliographically approved
Varmuza, K., Filzmoser, P., Hoffmann, I., Walach, J., Cottin, H., Fray, N., . . . Hilchenbach, M. (2018). Significance of variables for discrimination: Applied to the search of organic ions in mass spectra measured on cometary particles. Journal of Chemometrics, 32(4), Article ID e3001.
Open this publication in new window or tab >>Significance of variables for discrimination: Applied to the search of organic ions in mass spectra measured on cometary particles
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2018 (English)In: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128X, Vol. 32, no 4, article id e3001Article in journal (Refereed) Published
Abstract [en]

The instrument Cometary Secondary Ion Mass Analyzer (COSIMA) on board of the European Space Agency mission Rosetta to the comet 67P/Churyumov-Gerasimenko is a secondary ion mass spectrometer with a time-of-flight mass analyzer. It collected near the comet several thousand particles, imaged them, and analyzed the elemental and chemical compositions of their surfaces. In this study, variables have been generated from the spectral data covering the mass ranges of potential C-, H-, N-, and O-containing ions. The variable importance in binary discriminations between spectra measured on cometary particles and those measured on the target background has been estimated by the univariate t test and the multivariate methods discriminant partial least squares, random forest, and a robust method based on the log ratios of all variable pairs. The results confirm the presence of organic substances in cometary matter-probably a complex macromolecular mixture.

Keywords
Classification, Comet 67P/Churyumov-Gerasimenko, D-PLS, Pairwise log ratios, Random forest, Rosetta, Time-of-flight secondary ion mass spectrometry, Variable importance
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33270 (URN)10.1002/cem.3001 (DOI)2-s2.0-85041032628 (Scopus ID)
Available from: 2018-02-12 Created: 2018-02-12 Last updated: 2018-12-20Bibliographically approved
Grady, M. M., Wright, I., Engrand, C. & Siljeström, S. (2018). The Rosetta mission and the chemistry of organic species in comet 67P/Churyumov-Gerasimenko. Elements, 14(2), 95-100
Open this publication in new window or tab >>The Rosetta mission and the chemistry of organic species in comet 67P/Churyumov-Gerasimenko
2018 (English)In: Elements, ISSN 1811-5209, E-ISSN 1811-5217, Vol. 14, no 2, p. 95-100Article in journal (Refereed) Published
Abstract [en]

Comets are regarded as probably the most primitive of solar system objects, preserving a record of the materials from which the solar system aggregated. Key amongst their components are organic compounds - molecules that may trace their heritage to the interstellar medium from which the protosolar nebula eventually emerged. The most recent cometary space mission, Rosetta, carried instruments designed to characterize, in unprecedented detail, the organic species in comet 67P/Churyumov-Gerasimenko (67P). Rosetta was the first mission to match orbits with a comet and follow its evolution over time, and also the first mission to land scientific instruments on a comet surface. Results from the mission revealed a greater variety of molecules than previously identified and indicated that 67P contained both primitive and processed organic entities. 

Keywords
Chemistry, Comet, Isotopes, Organics, Rosetta, Volatiles
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33781 (URN)10.2138/gselements.14.2.95 (DOI)2-s2.0-85045679352 (Scopus ID)
Available from: 2018-05-02 Created: 2018-05-02 Last updated: 2018-08-21Bibliographically approved
Fornaro, T., Boosman, A., Brucato, J. R., ten Kate, I. L., Siljeström, S., Poggiali, G., . . . Hazen, R. M. (2018). UV irradiation of biomarkers adsorbed on minerals under Martian-like conditions: Hints for life detection on Mars. Icarus (New York, N.Y. 1962), 313, 38-60
Open this publication in new window or tab >>UV irradiation of biomarkers adsorbed on minerals under Martian-like conditions: Hints for life detection on Mars
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2018 (English)In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, E-ISSN 1090-2643, Vol. 313, p. 38-60Article in journal (Refereed) Published
Abstract [en]

Laboratory simulations of Martian conditions are essential to develop quantitative models for the survival of organic biomarkers for future Mars exploration missions. In this work, we report the results of ultraviolet (UV) irradiation processing of biomarkers adsorbed on minerals under Martian-like conditions. Specifically, we prepared Mars soil analogues by doping forsterite, lizardite, antigorite, labradorite, natrolite, apatite and hematite minerals with organic compounds considered as potential biomarkers of extant terrestrial life such as the nucleotides adenosine monophosphate (AMP) and uridine monophosphate (UMP). We characterized such Mars soil analogues by means of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Confocal Raman Imaging Spectroscopy (CRIS), in order to get insights into the specific molecule-mineral interactions and explore the capabilities of different techniques to reveal diagnostic features of these biomarkers. Then, we performed irradiation experiments in the mid-UV spectral region under simulated Martian conditions and under terrestrial ambient conditions for comparison, monitoring the degradation process through DRIFTS. We observed that degradation under Martian-like conditions occurs much slower than in terrestrial ambient conditions. The minerals labradorite and natrolite mainly promote photodegradation of nucleotides, hematite and forsterite exhibit an intermediate degrading effect, while apatite, lizardite and antigorite do not show any significant catalytic effect on the degradation of the target organic species.

Keywords
Biomarkers, Infrared spectroscopy, Laboratory simulations, Mars soil analogues, Raman spectroscopy, ToF-SIMS
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34364 (URN)10.1016/j.icarus.2018.05.001 (DOI)2-s2.0-85047245545 (Scopus ID)
Note

 Funding details: TD1308-Origins; Funding details: NNX13AJ19G, NASA, National Aeronautics and Space Administration; Funding details: 198/15, SNSB, Swedish National Space Board; Funding details: ASI, Agenzia Spaziale Italiana; Funding details: UU, Universiteit Utrecht;

Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2019-02-05Bibliographically approved
Siljeström, S., Parenteau, M., Jahnke, L. & Cady, S. (2017). A comparative ToF-SIMS and GC–MS analysis of phototrophic communities collected from an alkaline silica-depositing hotspring. Organic Geochemistry, 109, 14-30
Open this publication in new window or tab >>A comparative ToF-SIMS and GC–MS analysis of phototrophic communities collected from an alkaline silica-depositing hotspring
2017 (English)In: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 109, p. 14-30Article in journal (Refereed) Published
Abstract [en]

One of few techniques that is able to spatially resolve chemical data, including organic molecules, to morphologicalfeatures in modern and ancient geological samples, is time-of-flight secondary ion mass spectrometry(ToF-SIMS). The ability to connect chemical data to morphology is key for interpreting thebiogenicity of preserved remains in ancient samples. However, due to the lack of reference data for geologicallyrelevant samples and the ease with which samples can be contaminated, ToF-SIMS data may bedifficult to interpret. In this project, we aimed to build a ToF-SIMS spectral database by performing parallelToF-SIMS and gas chromatography–mass spectrometry (GC–MS) analyses of extant photosyntheticmicrobial communities collected from an alkaline silica-depositing hot spring in Yellowstone NationalPark, USA. We built the library by analyzing samples of increasing complexity: pure lipid standards commonlyfound in thermophilic phototrophs, solvent extracts of specific lipid fractions, total lipid extracts,pure cultures of dominant phototrophic community members, and unsilicified phototrophic streamercommunities.The results showed that important lipids and pigments originating from phototrophs were detected byToF-SIMS (e.g., wax esters, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sufloquinovosyldiaglycerol,alkanes, etc.) in the streamer lipid extracts. Many of the lipids were also detected in situin the unsilicified streamer, and could even be spatially resolved to individual cells within the streamercommunity. Together with the ToF-SIMS database, this mapping ability will be used to further exploreother microbial mats and their fossilized counterparts in the geological record. This is likely to expandthe geochemical understanding of these types of samples.

Keywords
Lipids; ToF-SIMS; Imaging mass spectrometry; Microbial streamers; Hot springs
National Category
Natural Sciences Geochemistry
Identifiers
urn:nbn:se:ri:diva-30081 (URN)10.1016/j.orggeochem.2017.03.009 (DOI)2-s2.0-85018274698 (Scopus ID)
Funder
Swedish National Space BoardSwedish Research Council
Available from: 2017-07-07 Created: 2017-07-07 Last updated: 2019-01-07Bibliographically approved
Drake, H., Ivarsson, M., Bengtson, S., Heim, C., Siljeström, S., Whitehouse, M. J., . . . Åström, M. E. (2017). Anaerobic consortia of fungi and sulfate reducing bacteria in deep granite fractures. Nature Communications, 8(1), Article ID 55.
Open this publication in new window or tab >>Anaerobic consortia of fungi and sulfate reducing bacteria in deep granite fractures
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2017 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, no 1, article id 55Article in journal (Refereed) Published
Abstract [en]

The deep biosphere is one of the least understood ecosystems on Earth. Although most microbiological studies in this system have focused on prokaryotes and neglected microeukaryotes, recent discoveries have revealed existence of fossil and active fungi in marine sediments and sub-seafloor basalts, with proposed importance for the subsurface energy cycle. However, studies of fungi in deep continental crystalline rocks are surprisingly few. Consequently, the characteristics and processes of fungi and fungus-prokaryote interactions in this vast environment remain enigmatic. Here we report the first findings of partly organically preserved and partly mineralized fungi at great depth in fractured crystalline rock (-740 m). Based on environmental parameters and mineralogy the fungi are interpreted as anaerobic. Synchrotron-based techniques and stable isotope microanalysis confirm a coupling between the fungi and sulfate reducing bacteria. The cryptoendolithic fungi have significantly weathered neighboring zeolite crystals and thus have implications for storage of toxic wastes using zeolite barriers. © 2017 The Author(s).

Keywords
Fungi, Prokaryota
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-30780 (URN)10.1038/s41467-017-00094-6 (DOI)2-s2.0-85021701127 (Scopus ID)
Available from: 2017-08-23 Created: 2017-08-23 Last updated: 2018-08-21Bibliographically approved
Hilchenbach, M., Fischer, H., Langevin, Y., Merouane, S., Paquette, J., Rynö, J., . . . Zaprudin, B. (2017). Mechanical and electrostatic experiments with dust particles collected in the inner coma of comet 67P by COSIMA onboard Rosetta. Philosophical Transactions. Series A: Mathematical, physical, and engineering science, 375(2097)
Open this publication in new window or tab >>Mechanical and electrostatic experiments with dust particles collected in the inner coma of comet 67P by COSIMA onboard Rosetta
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2017 (English)In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 375, no 2097Article in journal (Refereed) Published
Abstract [en]

The in situ cometary dust particle instrument COSIMA (COmetary Secondary Ion Mass Analyser) onboard ESA's Rosetta mission has collected about 31 000 dust particles in the inner coma of comet 67P/Churyumov-Gerasimenko since August 2014. The particles are identified by optical microscope imaging and analysed by time-of-flight secondary ion mass spectrometry. After dust particle collection by low speed impact on metal targets, the collected particle morphology points towards four families of cometary dust particles. COSIMA is an in situ laboratory that operates remotely controlled next to the comet nucleus. The particles can be further manipulated within the instrument by mechanical and electrostatic means after their collection by impact. The particles are stored above 0°C in the instrument and the experiments are carried out on the refractory, ice-free matter of the captured cometary dust particles. An interesting particle morphology class, the compact particles, is not fragmented on impact. One of these particles was mechanically pressed and thereby crushed into large fragments. The particles are good electrical insulators and transform into rubble pile agglomerates by the application of an energetic indium ion beam during the secondary ion mass spectrometry analysis. This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Authors.

Keywords
Coma, Comet, Dust, Fragmentation Author for correspondence:, Electrostatics, Ion beams, Ions, Mass spectrometry, Piles, Secondary emission, Secondary ion mass spectrometry, Spectrometry, 67p/churyumov-gerasimenko, Electrical insulators, Fragmentation Author for correspondence, Particle morphologies, Rosetta mission, Time of flight secondary ion mass spectrometry
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-30265 (URN)10.1098/rsta.2016.0255 (DOI)2-s2.0-85020220282 (Scopus ID)
Available from: 2017-08-11 Created: 2017-08-11 Last updated: 2019-01-22Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4975-6074

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