Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland
The microbial communities inferred in silica sinter rocks, based on multiscale morphological features (fabrics and textures) and the presence of lipid biomarkers and their carbon isotopic composition, are evaluated in the Krýsuvík geothermal area of Iceland. Close to vent environments (T > 75 °C...
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ftmdpi:oai:mdpi.com:/2075-163X/11/3/263/ 2023-08-20T04:07:26+02:00 Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland Jose Javier Álvaro Mónica Sánchez-Román Klaas G.J. Nierop Francien Peterse agris 2021-03-04 application/pdf https://doi.org/10.3390/min11030263 EN eng Multidisciplinary Digital Publishing Institute https://dx.doi.org/10.3390/min11030263 https://creativecommons.org/licenses/by/4.0/ Minerals; Volume 11; Issue 3; Pages: 263 silicified microbe texture fabric biomarker carbon isotope microbial mat Text 2021 ftmdpi https://doi.org/10.3390/min11030263 2023-08-01T01:12:08Z The microbial communities inferred in silica sinter rocks, based on multiscale morphological features (fabrics and textures) and the presence of lipid biomarkers and their carbon isotopic composition, are evaluated in the Krýsuvík geothermal area of Iceland. Close to vent environments (T > 75 °C and pH 1.7‒3), stream floors are capped with homogeneous vitreous crusts and breccia levels, with no distinct recognizable silicified microbes. About 4 m far from the vents (T 75‒60 °C and pH 3‒6) and beyond (T < 60 °C and pH 6‒7.6), microbial sinters, including wavy and palisade laminated and bubble fabrics, differ between abandoned meanders and desiccated ponds. Fabric and texture variances are related to changes in the ratio of filament/coccoid silicified microbes and associated porosity. Coatings of epicellular silica, less than 2 µm thick, favor identification of individual microbial filaments, whereas coalescence of opal spheres into agglomerates precludes recognition of original microbial textures and silicified microbes. Episodic fluctuations in the physico-chemical conditions of surface waters controlled the acidic hydrolysis of biomarkers. Wavy laminated fabrics from pond margins comprise fatty acids, mono- and dialkyl glycerol, mono- and diethers, monoalkyl glycerol esters and small traces of 10-methyl branched C16 and C18 fatty acids and archaeol, indicative of intergrowths of cyanobacteria, Aquificales, and sulfate reducing bacteria and methanogenic archaea. In contrast, wavy laminated fabrics from abandoned meanders and palisade laminated fabrics from ponds differ in their branched fatty acids and the presence vs. absence of bacteriohopanetetrol, reflecting different cyanobacterial contributions. δ13C values of biomarkers range from −22.7 to −32.9‰, but their values in the wavy (pond) and bubble fabrics have much wider ranges than those of the wavy (meander), palisade, and vitreous fabrics, reflecting dissolved inorganic carbon (DIC) sources and a decrease in 13C downstream outflow channels, with ... Text Iceland MDPI Open Access Publishing Krýsuvík ENVELOPE(-22.052,-22.052,63.897,63.897) Minerals 11 3 263 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
silicified microbe texture fabric biomarker carbon isotope microbial mat |
spellingShingle |
silicified microbe texture fabric biomarker carbon isotope microbial mat Jose Javier Álvaro Mónica Sánchez-Román Klaas G.J. Nierop Francien Peterse Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland |
topic_facet |
silicified microbe texture fabric biomarker carbon isotope microbial mat |
description |
The microbial communities inferred in silica sinter rocks, based on multiscale morphological features (fabrics and textures) and the presence of lipid biomarkers and their carbon isotopic composition, are evaluated in the Krýsuvík geothermal area of Iceland. Close to vent environments (T > 75 °C and pH 1.7‒3), stream floors are capped with homogeneous vitreous crusts and breccia levels, with no distinct recognizable silicified microbes. About 4 m far from the vents (T 75‒60 °C and pH 3‒6) and beyond (T < 60 °C and pH 6‒7.6), microbial sinters, including wavy and palisade laminated and bubble fabrics, differ between abandoned meanders and desiccated ponds. Fabric and texture variances are related to changes in the ratio of filament/coccoid silicified microbes and associated porosity. Coatings of epicellular silica, less than 2 µm thick, favor identification of individual microbial filaments, whereas coalescence of opal spheres into agglomerates precludes recognition of original microbial textures and silicified microbes. Episodic fluctuations in the physico-chemical conditions of surface waters controlled the acidic hydrolysis of biomarkers. Wavy laminated fabrics from pond margins comprise fatty acids, mono- and dialkyl glycerol, mono- and diethers, monoalkyl glycerol esters and small traces of 10-methyl branched C16 and C18 fatty acids and archaeol, indicative of intergrowths of cyanobacteria, Aquificales, and sulfate reducing bacteria and methanogenic archaea. In contrast, wavy laminated fabrics from abandoned meanders and palisade laminated fabrics from ponds differ in their branched fatty acids and the presence vs. absence of bacteriohopanetetrol, reflecting different cyanobacterial contributions. δ13C values of biomarkers range from −22.7 to −32.9‰, but their values in the wavy (pond) and bubble fabrics have much wider ranges than those of the wavy (meander), palisade, and vitreous fabrics, reflecting dissolved inorganic carbon (DIC) sources and a decrease in 13C downstream outflow channels, with ... |
format |
Text |
author |
Jose Javier Álvaro Mónica Sánchez-Román Klaas G.J. Nierop Francien Peterse |
author_facet |
Jose Javier Álvaro Mónica Sánchez-Román Klaas G.J. Nierop Francien Peterse |
author_sort |
Jose Javier Álvaro |
title |
Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland |
title_short |
Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland |
title_full |
Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland |
title_fullStr |
Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland |
title_full_unstemmed |
Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland |
title_sort |
multiscale microbial preservation and biogeochemical signals in a modern hot-spring siliceous sinter rich in co2 emissions, krýsuvík geothermal field, iceland |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2021 |
url |
https://doi.org/10.3390/min11030263 |
op_coverage |
agris |
long_lat |
ENVELOPE(-22.052,-22.052,63.897,63.897) |
geographic |
Krýsuvík |
geographic_facet |
Krýsuvík |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Minerals; Volume 11; Issue 3; Pages: 263 |
op_relation |
https://dx.doi.org/10.3390/min11030263 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/min11030263 |
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Minerals |
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11 |
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3 |
container_start_page |
263 |
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1774719053719404544 |