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Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore

The Sembawang Hot Spring in Singapore lies at the foot of a major regional geological feature called the Bentong-Raub Suture Zone. Amid an extensively managed surface geothermal park, an undisturbed hot spring emerges with source water at 61°C, pH 6.8, and 1 mg/L dissolved sulfide. A small main pool...

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Autores principales: George, Christaline, Lim, Chloe Xue Qi, Tong, Yan, Pointing, Stephen Brian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10313338/
https://www.ncbi.nlm.nih.gov/pubmed/37396374
http://dx.doi.org/10.3389/fmicb.2023.1189468
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author George, Christaline
Lim, Chloe Xue Qi
Tong, Yan
Pointing, Stephen Brian
author_facet George, Christaline
Lim, Chloe Xue Qi
Tong, Yan
Pointing, Stephen Brian
author_sort George, Christaline
collection PubMed
description The Sembawang Hot Spring in Singapore lies at the foot of a major regional geological feature called the Bentong-Raub Suture Zone. Amid an extensively managed surface geothermal park, an undisturbed hot spring emerges with source water at 61°C, pH 6.8, and 1 mg/L dissolved sulfide. A small main pool at the source supported orange-green benthic flocs, whereas the outflow channel with gradually less extreme environmental stress supported extensive vivid green microbial mats. Microscopy revealed that cyanobacterial morphotypes were distinct in flocs and mats at several intervals along the environmental gradient, and we describe a spiraling pattern in the oscillatorian cyanobacteria that may reflect response to poly-extreme stress. Estimation of diversity using 16S rRNA gene sequencing revealed assemblages that were dominated by phototrophic bacteria. The most abundant taxa in flocs at 61°C/1 mg/L sulfide were Roseiflexus sp. and Thermosynechococcus elongatus, whilst the mats at 45.7–55.3°C/0–0.5 mg/L sulfide were dominated by Oscillatoriales cyanobacterium MTP1 and Chloroflexus sp. Occurrence of diverse chemoautotrophs and heterotrophs reflected known thermal ranges for taxa, and of note was the high abundance of thermophilic cellulolytic bacteria that likely reflected the large allochthonous leaf input. A clear shift in ASV-defined putative ecotypes occurred along the environmental stress gradient of the hot spring and overall diversity was inversely correlated to environmental stress. Significant correlations for abiotic variables with observed biotic diversity were identified for temperature, sulfide, and carbonate. A network analysis revealed three putative modules of biotic interactions that also reflected the taxonomic composition at intervals along the environmental gradient. Overall, the data indicated that three distinct microbial communities were supported within a small spatial scale along the poly-extreme environmental gradient. The findings add to the growing inventory of hot spring microbiomes and address an important biogeographic knowledge gap for the region.
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spelling pubmed-103133382023-07-01 Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore George, Christaline Lim, Chloe Xue Qi Tong, Yan Pointing, Stephen Brian Front Microbiol Microbiology The Sembawang Hot Spring in Singapore lies at the foot of a major regional geological feature called the Bentong-Raub Suture Zone. Amid an extensively managed surface geothermal park, an undisturbed hot spring emerges with source water at 61°C, pH 6.8, and 1 mg/L dissolved sulfide. A small main pool at the source supported orange-green benthic flocs, whereas the outflow channel with gradually less extreme environmental stress supported extensive vivid green microbial mats. Microscopy revealed that cyanobacterial morphotypes were distinct in flocs and mats at several intervals along the environmental gradient, and we describe a spiraling pattern in the oscillatorian cyanobacteria that may reflect response to poly-extreme stress. Estimation of diversity using 16S rRNA gene sequencing revealed assemblages that were dominated by phototrophic bacteria. The most abundant taxa in flocs at 61°C/1 mg/L sulfide were Roseiflexus sp. and Thermosynechococcus elongatus, whilst the mats at 45.7–55.3°C/0–0.5 mg/L sulfide were dominated by Oscillatoriales cyanobacterium MTP1 and Chloroflexus sp. Occurrence of diverse chemoautotrophs and heterotrophs reflected known thermal ranges for taxa, and of note was the high abundance of thermophilic cellulolytic bacteria that likely reflected the large allochthonous leaf input. A clear shift in ASV-defined putative ecotypes occurred along the environmental stress gradient of the hot spring and overall diversity was inversely correlated to environmental stress. Significant correlations for abiotic variables with observed biotic diversity were identified for temperature, sulfide, and carbonate. A network analysis revealed three putative modules of biotic interactions that also reflected the taxonomic composition at intervals along the environmental gradient. Overall, the data indicated that three distinct microbial communities were supported within a small spatial scale along the poly-extreme environmental gradient. The findings add to the growing inventory of hot spring microbiomes and address an important biogeographic knowledge gap for the region. Frontiers Media S.A. 2023-06-16 /pmc/articles/PMC10313338/ /pubmed/37396374 http://dx.doi.org/10.3389/fmicb.2023.1189468 Text en Copyright © 2023 George, Lim, Tong and Pointing. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
George, Christaline
Lim, Chloe Xue Qi
Tong, Yan
Pointing, Stephen Brian
Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore
title Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore
title_full Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore
title_fullStr Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore
title_full_unstemmed Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore
title_short Community structure of thermophilic photosynthetic microbial mats and flocs at Sembawang Hot Spring, Singapore
title_sort community structure of thermophilic photosynthetic microbial mats and flocs at sembawang hot spring, singapore
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10313338/
https://www.ncbi.nlm.nih.gov/pubmed/37396374
http://dx.doi.org/10.3389/fmicb.2023.1189468
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