Biomarkers of Endolithic Communities within Gypsum Crusts (Southern Tunisia)

Stivaletta, Nunzia; López‐García, Purificación; Boihem, L. L.; Millie, David F.; Barbieri, Roberto

doi:10.1080/01490450903410431

Cited by 42 publications

(35 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In hyper-arid environments (Atacama Desert, the Mojave Desert and Al-Jafr Basin) gypsum community evenness was also variable since Cyanobacteria dominated (79%) the Al-Jafr Basin population and represented only 18% of the Mojave Desert population (Dong et al 2007). Archaea were not detected in the Tunisian crust samples (Stivaletta et al 2010); however, the population of Nitrososphaeraceae found in GYQ-008 was consistent with the Thaumarchaea-dominated population found in the high Arctic (Ziolkowski et al 2013). Cyanobacteria made up of a comparatively smaller (1-3%) part of cryptoendolith population in the LSM impact structure.…”

Section: Microbial Communitysupporting

confidence: 61%

“…Gypsum crusts in Tunisia had populations that included Cyanobacteria, Actinobacteria, Proteobacteria, Bacteroidetes, Deinococus and Flavobacteria; however, population evenness varied between samples as a result of Cyanobacteria dominance (<15 to >80%) (Stivaletta et al 2010). Gypsum crusts in Tunisia had populations that included Cyanobacteria, Actinobacteria, Proteobacteria, Bacteroidetes, Deinococus and Flavobacteria; however, population evenness varied between samples as a result of Cyanobacteria dominance (<15 to >80%) (Stivaletta et al 2010).…”

Section: Microbial Communitymentioning

confidence: 98%

See 1 more Smart Citation

Gypsum-hosted endolithic communities of the Lake St. Martin impact structure, Manitoba, Canada: spectroscopic detectability and implications for Mars

Rhind

Ronholm

Berg

et al. 2014

International Journal of Astrobiology

View full text Add to dashboard Cite

There is increasing evidence that Mars may have once been a habitable environment. Gypsum is targeted in the search for Martian biosignatures because it can host extensive cryptoendolithic communities in extreme terrestrial environments and is widespread on Mars. In this study the viability of using different spectroscopy-based techniques to identify the presence of gypsum endolithic communities was investigated by analysing various cryptoendoliths collected from the Lake St. Martin impact crater (LSM), a Mars analogue site found in Manitoba, Canada. Concurrently, the cryptoendolithic microbial community structure present was also analysed to aid in assigning spectroscopic features to microbial community members. Two main morphologies of endolithic communities were collected from gypsum deposits at LSM: true cryptoendolithic communities and annular deposits on partially buried boulders and cobbles <1 cm below the soil surface. Endolithic communities were found to be visibly present only in gypsum with a high degree of translucency and could occur as deep as 3 cm below the exterior surface. The bacterial community was dominated by a phylum (Chloroflexi) that has not been previously observed in gypsum endoliths. The exterior surfaces of gypsum boulders and cobbles are devoid of spectroscopic features attributable to organic molecules and detectable by reflectance, Raman, or ultraviolet-induced fluorescence spectroscopies. However, exposed interior surfaces show unique endolithic signatures detectable by each spectroscopic technique. This indicates that cryptoendolithic communities can be detected via spectroscopy-based techniques, provided they are either partially or fully exposed and enough photon-target interactions occur to enable detection.

show abstract

Section: Microbial Communitysupporting

confidence: 61%

Section: Microbial Communitymentioning

confidence: 98%

Gypsum-hosted endolithic communities of the Lake St. Martin impact structure, Manitoba, Canada: spectroscopic detectability and implications for Mars

Rhind

Ronholm

Berg

et al. 2014

International Journal of Astrobiology

View full text Add to dashboard Cite

show abstract

“…Should the habitability of this fluid system have been taken advantage of by early life forms (if present on Mars), sulphates have been shown to preserve organic molecules on geologically relevant timescales (Aubrey et al 2006;Schopf et al 2012). Additionally, endolithic communities such as those found in the LSM gypsum are ubiquitous in gypsum and other evaporitic minerals deposits on Earth, even in the most extreme settings (Friedmann 1982;Cockell et al 2002;Hughes & Lawley 2003;Stivaletta et al 2010).…”

Section: Discussionmentioning

confidence: 99%

“…Depending on the optical properties of the host rock, they can be found up to 10 mm in depth (Hughes & Lawley 2003). It is for this reason that communities like these are found in the most extreme environments on Earth, from the Atacama Desert to the high Arctic and Antarctic (Friedmann 1982;Cockell et al 2002;Hughes & Lawley 2003;Weirzchos et al 2006;Stivaletta et al 2010).…”

Section: Organic Biomarker Preservationmentioning

confidence: 99%

The persistence of a chlorophyll spectral biosignature from Martian evaporite and spring analogues under Mars-like conditions

Stromberg¹,

Applin

Cloutis

et al. 2013

International Journal of Astrobiology

View full text Add to dashboard Cite

Spring and evaporite deposits are considered two of the most promising environments for past habitability on Mars and preservation of biosignatures. Manitoba, Canada hosts the East German Creek (EGC) hypersaline spring complex, and the post impact evaporite gypsum beds of the Lake St. Martin (LSM) impact. The EGC complex has microbial mats, sediments, algae and biofabrics, while endolithic communities are ubiquitous in the LSM gypsum beds. These communities are spectrally detectable based largely on the presence of a chlorophyll absorption band at 670 nm; however, the robustness of this feature under Martian surface conditions was unclear. Biological and biology-bearing samples from EGC and LSM were exposed to conditions similar to the surface of present day Mars (high UV flux, 100 mbar, anoxic, CO 2 rich) for up to 44 days, and preservation of the 670 nm chlorophyll feature and chlorophyll red-edge was observed. A decrease in band depth of the 670 nm band ranging from *16 to 80% resulted, with correlations seen in the degree of preservation and the spatial proximity of samples to the spring mound and mineral shielding effects. The spectra were deconvolved to Mars Exploration Rover (MER) Pancam and Mars Science Laboratory (MSL) Mastcam science filter bandpasses to investigate the detectability of the 670 nm feature and to compare with common mineral features. The red-edge and 670 nm feature associated with chlorophyll can be distinguished from the spectra of minerals with features below *1000 nm, such as hematite and jarosite. However, distinguishing goethite from samples with the chlorophyll feature is more problematic, and quantitative interpretation using band depth data makes little distinction between iron oxyhydroxides and the 670 nm chlorophyll feature. The chlorophyll spectral feature is observable in both Pancam and Mastcam, and we propose that of the proposed EXOMARS Pancam filters, the PHYLL filter is best suited for its detection.

show abstract

“…Most studies focused on the first few millimeters under rock or scale surfaces (e.g., Horath and Bachofen 2006;Walker and Pace 2007b;Hallmann et al 2013) or describe rock substrata with outstanding susceptibility to endolithic attack like gypsum crusts from Tunesia and Anarctica (Stivaletta et al 2010;Ziolkowski et al 2013). In our study, the eukaryotic community in depth profiles from two sandstones with different pore textures was analyzed by 18S rRNA gene sequencing of environmental DNA.…”

Section: Introductionmentioning

confidence: 99%

Depth profiles of microbial colonization in sandstones

Hallmann

Friedenberger

Hause-Reitner

et al. 2015

Geomicrobiology Journal

View full text Add to dashboard Cite

Molecular methods allow a comprehensive view on uncultured microbial communities in dimension stone. In the presented study, we focus on depth profiles of microbial colonization in sandstones with different porosity and overall durability. The sandstones were exposed to the environment for several years and were covered with a dense brown-greenish biofilm. Samples from the stone surface, from 0.5 cm and from 3.0 cm depths were taken under sterile conditions and subjected to analysis of microbial DNA (sequencing of 18S rRNA genes) and culturing experiments. A silica cemented Buntsandstein was just colonized at the stone surface, predominantly with algal and fungal microorganisms. Here, no environmental DNA could be isolated from depth profiles. From a calcitic Chirotheriensandstein with high pore size (shown by thin sections), environmental DNA from depths down to 3 cm could be retrieved. Apart from filamentous fungi and algae, mosses clearly dominated the microbial community. Hence, moss rhizoids or protonemata must be abundant as endoliths inside the stone material. It is reasonable to assume that the rhizoids may contribute to an increase in pore size by active penetration of the clastic material, even though colonization of the surface by mosses may not be necessarily obvious. This feature may imply stronger impact of stone decay induced by endolithic growth of bryophytes than hitherto observed.

show abstract

Biomarkers of Endolithic Communities within Gypsum Crusts (Southern Tunisia)

Cited by 42 publications

References 68 publications

Gypsum-hosted endolithic communities of the Lake St. Martin impact structure, Manitoba, Canada: spectroscopic detectability and implications for Mars

Gypsum-hosted endolithic communities of the Lake St. Martin impact structure, Manitoba, Canada: spectroscopic detectability and implications for Mars

The persistence of a chlorophyll spectral biosignature from Martian evaporite and spring analogues under Mars-like conditions

Depth profiles of microbial colonization in sandstones

Contact Info

Product

Resources

About