Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes

The study of microbial mats in extreme environments is of high scientific interest from geological, ecological, and geomicrobiological aspects. These mats represent multilayer bio-structures where each taxonomic group dominates a specific vertical layering distribution resulting from its growth and...

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Main Authors: Christos Kanellopoulos, Vasiliki Lamprinou, Artemis Politi, Panagiotis Voudouris, Ioannis Iliopoulos, Maria Kokkaliari, Leonidas Moforis, Athena Economou-Amilli
Format: Article
Language:English
Published: MDPI AG 2022-11-01
Series:Minerals
Subjects:
Online Access:https://www.mdpi.com/2075-163X/12/11/1408
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author Christos Kanellopoulos
Vasiliki Lamprinou
Artemis Politi
Panagiotis Voudouris
Ioannis Iliopoulos
Maria Kokkaliari
Leonidas Moforis
Athena Economou-Amilli
author_facet Christos Kanellopoulos
Vasiliki Lamprinou
Artemis Politi
Panagiotis Voudouris
Ioannis Iliopoulos
Maria Kokkaliari
Leonidas Moforis
Athena Economou-Amilli
author_sort Christos Kanellopoulos
collection DOAJ
description The study of microbial mats in extreme environments is of high scientific interest from geological, ecological, and geomicrobiological aspects. These mats represent multilayer bio-structures where each taxonomic group dominates a specific vertical layering distribution resulting from its growth and metabolic activity. In the present study, microbial mats in a hot spring environment from Aedipsos (Euboea Island, Greece) resulting in the creation of thermogenic travertine, were studied through an interdisciplinary approach. The mineralogical composition was determined by optical microscopy, XRD, and SEM-EDS microanalysis, and the identification of Cyanobacteria was made primarily on morphological characteristics. The main mineral phase in the studied samples is calcite and, to a less extent, aragonite, with several trace elements in the mineral-chemistry composition, i.e., up to 1.93 wt. % MgO, up to 0.52 wt. % SrO, up to 0.44 wt. % Na<sub>2</sub>O, up to 0.17 wt. % K<sub>2</sub>O, and up to 3.99 wt. % SO<sub>3</sub>. The dominant facies are lamination and shrubs, which are the most common among the facies of thermogenic travertines of the area. Several layers were identified, (i) a top mainly abiotic layer consisting of calcium carbonate micritic crystals, (ii) a second biotic layer–the Cyanobacteria layer, dominated by the species <i>Leptolyngbya perforans</i>, (iii) a third biotic layer where <i>Leptolyngbya perforans</i>, <i>Chloroflexus</i> and other bacteria occur, and (iv) a deeper abiotic part with several layers where no photosynthetic microorganisms occur. In the upper layers, nineteen (19) species of Cyanobacteria were identified, classified in the orders Chroococcales (37%), Synechococcales (31%), Oscillatoriales (16%), and Spirulinales (6%). Among the identified Cyanobacteria, there are typical thermophilic and limestone substrate species. These Cyanobacteria are found to participate in the biomineralization and biologically-influenced processes, i.e., (i) filamentous Cyanobacteria are trapping calcium carbonate crystals, and diatoms, (ii) extracellular polymeric substances (EPS) create crystal retention lattice contributing to the biomineralization process, and (iii) filamentous sheaths of Cyanobacteria are calcified, resulting in the creation of calcium carbonate tubes.
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spelling doaj.art-c5c3854a93a34a8bada6eedf27b128ba2023-11-24T05:58:56ZengMDPI AGMinerals2075-163X2022-11-011211140810.3390/min12111408Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization ProcessesChristos Kanellopoulos0Vasiliki Lamprinou1Artemis Politi2Panagiotis Voudouris3Ioannis Iliopoulos4Maria Kokkaliari5Leonidas Moforis6Athena Economou-Amilli7Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis, Ano Ilissia, 15784 Athens, GreeceFaculty of Biology, Department of Ecology and Systematics, National and Kapodistrian University of Athens, Panepistimiopolis, Ano Ilissia, 15784 Athens, GreeceFaculty of Biology, Department of Ecology and Systematics, National and Kapodistrian University of Athens, Panepistimiopolis, Ano Ilissia, 15784 Athens, GreeceFaculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis, Ano Ilissia, 15784 Athens, GreeceDepartment of Geology, University of Patras, 26500 Rio, GreeceDepartment of Geology, University of Patras, 26500 Rio, GreeceFaculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis, Ano Ilissia, 15784 Athens, GreeceFaculty of Biology, Department of Ecology and Systematics, National and Kapodistrian University of Athens, Panepistimiopolis, Ano Ilissia, 15784 Athens, GreeceThe study of microbial mats in extreme environments is of high scientific interest from geological, ecological, and geomicrobiological aspects. These mats represent multilayer bio-structures where each taxonomic group dominates a specific vertical layering distribution resulting from its growth and metabolic activity. In the present study, microbial mats in a hot spring environment from Aedipsos (Euboea Island, Greece) resulting in the creation of thermogenic travertine, were studied through an interdisciplinary approach. The mineralogical composition was determined by optical microscopy, XRD, and SEM-EDS microanalysis, and the identification of Cyanobacteria was made primarily on morphological characteristics. The main mineral phase in the studied samples is calcite and, to a less extent, aragonite, with several trace elements in the mineral-chemistry composition, i.e., up to 1.93 wt. % MgO, up to 0.52 wt. % SrO, up to 0.44 wt. % Na<sub>2</sub>O, up to 0.17 wt. % K<sub>2</sub>O, and up to 3.99 wt. % SO<sub>3</sub>. The dominant facies are lamination and shrubs, which are the most common among the facies of thermogenic travertines of the area. Several layers were identified, (i) a top mainly abiotic layer consisting of calcium carbonate micritic crystals, (ii) a second biotic layer–the Cyanobacteria layer, dominated by the species <i>Leptolyngbya perforans</i>, (iii) a third biotic layer where <i>Leptolyngbya perforans</i>, <i>Chloroflexus</i> and other bacteria occur, and (iv) a deeper abiotic part with several layers where no photosynthetic microorganisms occur. In the upper layers, nineteen (19) species of Cyanobacteria were identified, classified in the orders Chroococcales (37%), Synechococcales (31%), Oscillatoriales (16%), and Spirulinales (6%). Among the identified Cyanobacteria, there are typical thermophilic and limestone substrate species. These Cyanobacteria are found to participate in the biomineralization and biologically-influenced processes, i.e., (i) filamentous Cyanobacteria are trapping calcium carbonate crystals, and diatoms, (ii) extracellular polymeric substances (EPS) create crystal retention lattice contributing to the biomineralization process, and (iii) filamentous sheaths of Cyanobacteria are calcified, resulting in the creation of calcium carbonate tubes.https://www.mdpi.com/2075-163X/12/11/1408microbial matsbiomineralizationCyanobacteriatravertinehot springsAedipsos (Edipsos)
spellingShingle Christos Kanellopoulos
Vasiliki Lamprinou
Artemis Politi
Panagiotis Voudouris
Ioannis Iliopoulos
Maria Kokkaliari
Leonidas Moforis
Athena Economou-Amilli
Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes
Minerals
microbial mats
biomineralization
Cyanobacteria
travertine
hot springs
Aedipsos (Edipsos)
title Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes
title_full Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes
title_fullStr Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes
title_full_unstemmed Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes
title_short Microbial Mat Stratification in Travertine Depositions of Greek Hot Springs and Biomineralization Processes
title_sort microbial mat stratification in travertine depositions of greek hot springs and biomineralization processes
topic microbial mats
biomineralization
Cyanobacteria
travertine
hot springs
Aedipsos (Edipsos)
url https://www.mdpi.com/2075-163X/12/11/1408
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