Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress
Cyanobacterial mats are often a major biological component of extreme aquatic ecosystems, and in polar lakes and streams they may account for the dominant fraction of total ecosystem biomass and productivity. In this study we examined the vertical structure and physiology of Arctic microbial mats re...
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ftpubmed:oai:pubmedcentral.nih.gov:3337508 2023-05-15T14:56:49+02:00 Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress Lionard, Marie Péquin, Bérangère Lovejoy, Connie Vincent, Warwick F. 2012-04-26 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337508 http://www.ncbi.nlm.nih.gov/pubmed/22557996 https://doi.org/10.3389/fmicb.2012.00140 en eng Frontiers Research Foundation http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337508 http://www.ncbi.nlm.nih.gov/pubmed/22557996 http://dx.doi.org/10.3389/fmicb.2012.00140 Copyright © 2012 Lionard, Péquin, Lovejoy and Vincent. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited. CC-BY-NC Microbiology Text 2012 ftpubmed https://doi.org/10.3389/fmicb.2012.00140 2013-09-04T06:18:17Z Cyanobacterial mats are often a major biological component of extreme aquatic ecosystems, and in polar lakes and streams they may account for the dominant fraction of total ecosystem biomass and productivity. In this study we examined the vertical structure and physiology of Arctic microbial mats relative to the question of how these communities may respond to ongoing environmental change. The mats were sampled from Ward Hunt Lake (83°5.297′N, 74°9.985′W) at the northern coast of Arctic Canada, and were composed of three visibly distinct layers. Microsensor profiling showed that there were strong gradients in oxygen within each layer, with an overall decrease from 100% saturation at the mat surface to 0%, at the bottom, accompanied by an increase of 0.6 pH units down the profile. Gene clone libraries (16S rRNA) revealed the presence of Oscillatorian sequences throughout the mat, while Nostoc related species dominated the two upper layers, and Nostocales and Synechococcales sequences were common in the bottom layer. High performance liquid chromatography analyses showed a parallel gradient in pigments, from high concentrations of UV-screening scytonemin in the upper layer to increasing zeaxanthin and myxoxanthin in the bottom layer, and an overall shift from photoprotective to photosynthetic carotenoids down the profile. Climate change is likely to be accompanied by lake level fluctuations and evaporative concentration of salts, and thus increased osmotic stress of the littoral mat communities. To assess the cellular capacity to tolerate increasing osmolarity on physiology and cell membrane integrity, mat sections were exposed to a gradient of increasing salinities, and PAM measurements of in vivo chlorophyll fluorescence were made to assess changes in maximum quantum yield. The results showed that the mats were tolerant of up to a 46-fold increase in salinity. These features imply that cyanobacterial mats are resilient to ongoing climate change, and that in the absence of major biological perturbations, these ... Text Arctic Climate change PubMed Central (PMC) Arctic Canada Frontiers in Microbiology 3 |
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PubMed Central (PMC) |
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ftpubmed |
language |
English |
topic |
Microbiology |
spellingShingle |
Microbiology Lionard, Marie Péquin, Bérangère Lovejoy, Connie Vincent, Warwick F. Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress |
topic_facet |
Microbiology |
description |
Cyanobacterial mats are often a major biological component of extreme aquatic ecosystems, and in polar lakes and streams they may account for the dominant fraction of total ecosystem biomass and productivity. In this study we examined the vertical structure and physiology of Arctic microbial mats relative to the question of how these communities may respond to ongoing environmental change. The mats were sampled from Ward Hunt Lake (83°5.297′N, 74°9.985′W) at the northern coast of Arctic Canada, and were composed of three visibly distinct layers. Microsensor profiling showed that there were strong gradients in oxygen within each layer, with an overall decrease from 100% saturation at the mat surface to 0%, at the bottom, accompanied by an increase of 0.6 pH units down the profile. Gene clone libraries (16S rRNA) revealed the presence of Oscillatorian sequences throughout the mat, while Nostoc related species dominated the two upper layers, and Nostocales and Synechococcales sequences were common in the bottom layer. High performance liquid chromatography analyses showed a parallel gradient in pigments, from high concentrations of UV-screening scytonemin in the upper layer to increasing zeaxanthin and myxoxanthin in the bottom layer, and an overall shift from photoprotective to photosynthetic carotenoids down the profile. Climate change is likely to be accompanied by lake level fluctuations and evaporative concentration of salts, and thus increased osmotic stress of the littoral mat communities. To assess the cellular capacity to tolerate increasing osmolarity on physiology and cell membrane integrity, mat sections were exposed to a gradient of increasing salinities, and PAM measurements of in vivo chlorophyll fluorescence were made to assess changes in maximum quantum yield. The results showed that the mats were tolerant of up to a 46-fold increase in salinity. These features imply that cyanobacterial mats are resilient to ongoing climate change, and that in the absence of major biological perturbations, these ... |
format |
Text |
author |
Lionard, Marie Péquin, Bérangère Lovejoy, Connie Vincent, Warwick F. |
author_facet |
Lionard, Marie Péquin, Bérangère Lovejoy, Connie Vincent, Warwick F. |
author_sort |
Lionard, Marie |
title |
Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress |
title_short |
Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress |
title_full |
Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress |
title_fullStr |
Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress |
title_full_unstemmed |
Benthic Cyanobacterial Mats in the High Arctic: Multi-Layer Structure and Fluorescence Responses to Osmotic Stress |
title_sort |
benthic cyanobacterial mats in the high arctic: multi-layer structure and fluorescence responses to osmotic stress |
publisher |
Frontiers Research Foundation |
publishDate |
2012 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337508 http://www.ncbi.nlm.nih.gov/pubmed/22557996 https://doi.org/10.3389/fmicb.2012.00140 |
geographic |
Arctic Canada |
geographic_facet |
Arctic Canada |
genre |
Arctic Climate change |
genre_facet |
Arctic Climate change |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337508 http://www.ncbi.nlm.nih.gov/pubmed/22557996 http://dx.doi.org/10.3389/fmicb.2012.00140 |
op_rights |
Copyright © 2012 Lionard, Péquin, Lovejoy and Vincent. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited. |
op_rightsnorm |
CC-BY-NC |
op_doi |
https://doi.org/10.3389/fmicb.2012.00140 |
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Frontiers in Microbiology |
container_volume |
3 |
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1766328879183560704 |