Gypsum endolithic phototrophs under moderate climate (Southern Sicily): their diversity and pigment composition

In this study, we used microscopic, spectroscopic, and molecular analysis to characterize endolithic colonization in gypsum (selenites and white crystalline gypsum) from several sites in Sicily. Our results showed that the dominant microorganisms in these environments are cyanobacteria, including: Chroococcidiopsis sp., Gloeocapsopsis pleurocapsoides, Gloeocapsa compacta, and Nostoc sp., as well as orange pigmented green microalgae from the Stephanospherinia clade. Single cell and filament sequencing coupled with 16S rRNA amplicon metagenomic profiling provided new insights into the phylogenetic and taxonomic diversity of the endolithic cyanobacteria. These organisms form differently pigmented zones within the gypsum. Our metagenomic profiling also showed differences in the taxonomic composition of endoliths in different gypsum varieties. Raman spectroscopy revealed that carotenoids were the most common pigments present in the samples. Other pigments such as gloeocapsin and scytonemin were also detected in the near-surface areas, suggesting that they play a significant role in the biology of endoliths in this environment. These pigments can be used as biomarkers for basic taxonomic identification, especially in case of cyanobacteria. The findings of this study provide new insights into the diversity and distribution of phototrophic microorganisms and their pigments in gypsum in Southern Sicily. Furthemore, this study highlights the complex nature of endolithic ecosystems and the effects of gypsum varieties on these communities, providing additional information on the general bioreceptivity of these environments.This project was supported by the Czech Science Foundation (Grant/Award No. 17-04270S and 21-03322S), Ministry of Education, Youth and Sports of the Czech Republic, National Programme of Sustainability I (Grant/Award No. LO1416), Charles University (Grant/Award Nos. UNCE/SCI/006 and UNCE 204069), ALGAMIC (Grant/Award No. CZ.1.05/2.1.00/19.0392). JM was supported by the Czech Science Foundation (GAČR) Project No. 22-06374S to accomplish phylogenetic and taxonomic analysis. JW was thankful for the financial support by the PGC2021-124362NB-I00 grant from MCI/AEI (Spain) and FEDER.Peer reviewe

Use of miniaturized Raman spectrometers under field conditions (sulphates)

Sulphates represent apparently an important component of Martian rocks and regolith. Their detection and identification is an integral part of the planned exploration missions, as they provide valuable information about the geological history of the planet. Also they could play a crucial exobiological role related with the possibility of existence of extinct or extant Martian life. This thesis provides a comprehensive overview of the occurrence and the geological situation of sulphates on the surface of Mars. The basic genetic factors responsible for formation of sulphates are introduced in terrestrial and Martian conditions. Furthermore, their significance is explained as indicators of geological factors and their connection with a possible Martian life. The second part presents method of Raman spectroscopy and its application in exobiology. The advantages and limitations of laboratory and portable instruments for analyzes exobiological samples are described. Identification capabilities of this method for determination of sulphates are shown, as well as its use on real locations considered as exobiological analogues. At the end, the current concept of Raman spectrometer for ExoMars rover is introduced. Keywords: Miniaturized Raman spectrometers, field conditions, sulphate

Aplikace Ramanovy spektrometrie pro detekci sulfátů hořících uhelných hald

Tato dizertační práce se zabývala využitím Ramanovy spektroskopie jako hlavní analytické metody pro identifikaci novotvořených minerálů, předně sulfátů, na hořících uhelných haldách. V tomto prostředí ovlivněném podpovrchovou termickou aktivitou vzniká řada neobvyklých či vzácných minerálů, které se vyznačují specifickými vlastnostmi jako je metastabilita, hygroskopie nebo vznik smíšených minerálních agregátů. Z tohoto důvodu je identifikace takových minerálních fází s použitím tradičních laboratorních metod ztížená. Mezi hlavní důvody využití Ramanovy spektroskopie patří nedestruktivnost metody, možnost rozlišení různě hydratovaných sulfátů, žádná nebo téměř žádná příprava vzorků a možnost terénního měření přímo v místě výskytu. Hlavní nevýhodou je nedostatek kompletních a spolehlivých spektroskopických dat studovaných minerálů. Z tohoto důvodu bylo laboratorně připraveno šest bezvodých sulfátů vzácně se vyskytujících v přírodě, u kterých byla laboratorním a přenosným spektrometrem získána Ramanova spektra a porovnána s hydratovanými analogy. Dále byla Ramanova spektroskope využita v kombinaci s dalšími metodami pro celkovou charakterizace dvou přírodních hlinitých sulfátů, alunogenu a khademitu. Jelikož se metastabilní fáze mohou po odběru rehydratovat nebo jinak transformovat, proběhlo testování...This Ph.D. thesis was focused on the application of Raman spectroscopy as the main analytical method for the characterization of neo-formed minerals, notably sulfates, from burning coal waste dumps. This environment associated with subsurface fires gives rise to a variety of uncommon and rare minerals. The specific features of these minerals (metastability, hygroscopy, mixed aggregates) causes that the mineralogical investigation is a challenging task using traditional laboratory-based techniques. Advantages such as the non-destructive nature, the sensitivity to the changes in the hydration degree of sulfates, little or none pretreatment, and the option of measurements directly in the field were the main reasons for applying this spectroscopy method. The scarce availability of spectroscopic data of most gas-vent minerals can be considered as the disadvantage. Therefore, artificial prepared samples of six anhydrous sulfates, which are rarely found in nature, were analyzed by Raman laboratory spectroscopy and a miniature a Raman spectrometer, and specific Raman features as well the differences with hydrated counterparts are shown. Laboratory investigation of two natural hydrated aluminum sulfates, alunogen and khademite, were carried out using Raman spectroscopy and other methods in order to obtain...Ústav geochemie, mineralogie a nerostných zdrojůInstitute of Geochemistry, Mineralogy and Mineral ResourcesPřírodovědecká fakultaFaculty of Scienc

Use of portable Raman spectrometers for detection of sulfates: potential application in exobiology

The detection of mineral phases under in situ conditions has become a primary but sometimes also challenging task in many fields of geoscience. Raman spectroscopy has been used as a powerful tool for the identification of various minerals and organic compounds. The advantages and the relative simplicity made this method a promising choice in the future planetary exploration missions to Mars. The deposits of aqueous minerals including sulfates have been found on the Martian surface. With the development of miniaturized handheld spectrometers there is a need for evaluation of Raman spectroscopy as a method of identification of sulfate phases in their natural conditions. In the first part of this work a handheld spectrometer equipped with 532 nm excitation laser was tested under laboratory conditions during which the ability to distinguish mineral samples representing sulfates of different chemical composition and different degree of hydration was investigated. In the second part, two handheld Raman spectrometers equipped with 532 and 785 nm excitation lasers were used for the characterization of sulfate phases on sites of their natural occurrence located in the Czech Republic. The quality of the Raman spectra acquired under outdoor conditions by both spectrometers was rather average but sufficient to..

Application of Raman spectroscopy for detection of sulfates of self-ignited coal heaps

This Ph.D. thesis was focused on the application of Raman spectroscopy as the main analytical method for the characterization of neo-formed minerals, notably sulfates, from burning coal waste dumps. This environment associated with subsurface fires gives rise to a variety of uncommon and rare minerals. The specific features of these minerals (metastability, hygroscopy, mixed aggregates) causes that the mineralogical investigation is a challenging task using traditional laboratory-based techniques. Advantages such as the non-destructive nature, the sensitivity to the changes in the hydration degree of sulfates, little or none pretreatment, and the option of measurements directly in the field were the main reasons for applying this spectroscopy method. The scarce availability of spectroscopic data of most gas-vent minerals can be considered as the disadvantage. Therefore, artificial prepared samples of six anhydrous sulfates, which are rarely found in nature, were analyzed by Raman laboratory spectroscopy and a miniature a Raman spectrometer, and specific Raman features as well the differences with hydrated counterparts are shown. Laboratory investigation of two natural hydrated aluminum sulfates, alunogen and khademite, were carried out using Raman spectroscopy and other methods in order to obtain..

Use of portable Raman spectrometers for detection of sulfates: potential application in exobiology

V dnešní době se detekce minerálních fází v podmínkách in situ stává prvořadým, leč někdy komplikovaným úkolem v mnoha geovědních oborech. Ramanova spektroskopie slouží jako výkonný nástroj pro identifikaci různých minerálů i organických sloučenin. Přednosti metody a relativní jednoduchost vedlo k jejímu možnému budoucímu využití v rámci vesmírných misí cílících na planetu Mars. Na jeho povrchu bylo zjištěno množství minerálů obsahujících vodu, včetně sulfátů. Spolu s rozvojem malých přenosných spektrometrů s různým excitačním zdrojem je zapotřebí testovat, jak Ramanova spektroskopie zvládá identifikovat sulfátové fáze v jejich přirozených podmínkách. V prvé části této práce je zkoušen v laboratorních podmínkách přenosný spektrometr vybavený laserem s excitací 532 nm na vzorcích zastupující sulfáty různého chemického složení a různým obsahem vody. V druhé části se využili přenosné spektrometry vybavené lasery s excitací 532 a 785 nm pro charakterizaci sulfátových fází na místech jejich přirozeného výskytu nalézajících se v České republice. Kvalita Ramanových spekter obou spektrometrů měřená v terénních podmínkách byla spíše průměrná, avšak postačila k rozlišení přítomných sulfátů. Jednoduché sulfáty (sádrovec, rozenit) lze identifikovat snadno. U sulfátů tvořící izomorfní směsi (jarosit, copiapit)...The detection of mineral phases under in situ conditions has become a primary but sometimes also challenging task in many fields of geoscience. Raman spectroscopy has been used as a powerful tool for the identification of various minerals and organic compounds. The advantages and the relative simplicity made this method a promising choice in the future planetary exploration missions to Mars. The deposits of aqueous minerals including sulfates have been found on the Martian surface. With the development of miniaturized handheld spectrometers there is a need for evaluation of Raman spectroscopy as a method of identification of sulfate phases in their natural conditions. In the first part of this work a handheld spectrometer equipped with 532 nm excitation laser was tested under laboratory conditions during which the ability to distinguish mineral samples representing sulfates of different chemical composition and different degree of hydration was investigated. In the second part, two handheld Raman spectrometers equipped with 532 and 785 nm excitation lasers were used for the characterization of sulfate phases on sites of their natural occurrence located in the Czech Republic. The quality of the Raman spectra acquired under outdoor conditions by both spectrometers was rather average but sufficient to...Institute of Geochemistry, Mineralogy and Mineral ResourcesÚstav geochemie, mineralogie a nerostných zdrojůPřírodovědecká fakultaFaculty of Scienc

Evaluation of miniaturized Raman spectrometers for planetary exploration : from aromatics to amino acids

Organic molecules are currently believed to be abundant in space, but the possible biogenic origin, or the mere existence, on some planetary surfaces, Mars specifically, is a pending question. Reliable methods of detection are required to answer this question unambiguously and Raman spectroscopy has already been suggested for this task years ago. With exploration missions aiming to Mars on the horizon, collecting experience and building databases will have crucial importance investigations of analytical data obtained through Raman instrumentation onboard of rovers in the frame of Mars 2020 and other forthcoming missions. This work focuses on the evaluation of some portable Raman systems coupled to different excitation lasers (532, 785, 1064 nm and a dual laser system with sequentially shifted excitation SSE) for the detection of various organic molecules, with emphasis on non-complicated measure protocol and observation of fluorescence emission when a different wavelength is used. By using a simple statistical approach, we demonstrate a generally good readability of the obtained spectra for most of the investigated organics regardless the excitation sources and instruments used. A varying level of fluorescence emission was encountered, resulting in higher background for the 532 nm and 785 nm instrumentation while 1064 nm and SSE spectrometers provided almost fluorescence-free spectra. These results illustrate how the relatively simple miniaturized Raman spectrometers can provide fast and unambiguous identification of various organic compounds which are of great importance in the current and future planetology and/or exobiology missions

Identification of tunnel structures in manganese oxide minerals using micro‐Raman spectroscopy

Manganese oxides have attracted the interest of many researchers due to their broad application field. These oxides possess various electrochemical, adsorption and catalysis properties and are as such applied in the industrial context, for example, steel industry, catalysis and removal of toxins in the ground or in waste water. In the archaeometrical field, manganese oxides have been used as pigments on various artefacts such as pottery and rock art paintings. The diversity of manganese oxide applications highlights the need for a well-defined Raman spectroscopic database with correct characterization of these compounds. However, identification of manganese oxides by Raman spectroscopy is challenging due to the wide variety of manganese oxides, and manganese oxides are weak Raman scatterers and are susceptible under the laser light. As such, characterization by Raman spectroscopy is not straight forward. In this research, we have focussed on seven natural, mineral (tunnel) samples that were identified by micro-Raman spectroscopy using two different laser wavelengths (785 and 532 nm). The experimental conditions were controlled to not introduce any modifications (degradation and/or phase transition) of the manganese oxide species. Both lasers have proven to be successful and were able to retrieve well-characterized Raman spectra for each of the manganese oxide phase, which were compared with published literature