Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes

ABSTRACT Humic lakes and ponds receive large amounts of terrestrial carbon and are important components of the global carbon cycle, yet how their redox cycling influences the carbon budget is not fully understood. Here we compared metagenomes obtained from a humic bog and a clear-water eutrophic lak...

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Autores principales:	Shaomei He, Maximilian P. Lau, Alexandra M. Linz, Eric E. Roden, Katherine D. McMahon
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2019
Materias:	Cyc2 extracellular electron transfer EET humic lake humic substances HS Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/6bfbef21714142578feacede273af345
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spelling	oai:doaj.org-article:6bfbef21714142578feacede273af3452021-11-15T15:22:04ZExtracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes10.1128/mSphere.00436-182379-5042https://doaj.org/article/6bfbef21714142578feacede273af3452019-02-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mSphere.00436-18https://doaj.org/toc/2379-5042ABSTRACT Humic lakes and ponds receive large amounts of terrestrial carbon and are important components of the global carbon cycle, yet how their redox cycling influences the carbon budget is not fully understood. Here we compared metagenomes obtained from a humic bog and a clear-water eutrophic lake and found a much larger number of genes that might be involved in extracellular electron transfer (EET) for iron redox reactions and humic substance (HS) reduction in the bog than in the clear-water lake, consistent with the much higher iron and HS levels in the bog. These genes were particularly rich in the bog’s anoxic hypolimnion and were found in diverse bacterial lineages, some of which are relatives of known iron oxidizers or iron-HS reducers. We hypothesize that HS may be a previously overlooked electron acceptor and that EET-enabled redox cycling may be important in pelagic respiration and greenhouse gas budget in humic-rich freshwater lakes.Shaomei HeMaximilian P. LauAlexandra M. LinzEric E. RodenKatherine D. McMahonAmerican Society for MicrobiologyarticleCyc2extracellular electron transferEEThumic lakehumic substancesHSMicrobiologyQR1-502ENmSphere, Vol 4, Iss 1 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	Cyc2 extracellular electron transfer EET humic lake humic substances HS Microbiology QR1-502
spellingShingle	Cyc2 extracellular electron transfer EET humic lake humic substances HS Microbiology QR1-502 Shaomei He Maximilian P. Lau Alexandra M. Linz Eric E. Roden Katherine D. McMahon Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes
description	ABSTRACT Humic lakes and ponds receive large amounts of terrestrial carbon and are important components of the global carbon cycle, yet how their redox cycling influences the carbon budget is not fully understood. Here we compared metagenomes obtained from a humic bog and a clear-water eutrophic lake and found a much larger number of genes that might be involved in extracellular electron transfer (EET) for iron redox reactions and humic substance (HS) reduction in the bog than in the clear-water lake, consistent with the much higher iron and HS levels in the bog. These genes were particularly rich in the bog’s anoxic hypolimnion and were found in diverse bacterial lineages, some of which are relatives of known iron oxidizers or iron-HS reducers. We hypothesize that HS may be a previously overlooked electron acceptor and that EET-enabled redox cycling may be important in pelagic respiration and greenhouse gas budget in humic-rich freshwater lakes.
format	article
author	Shaomei He Maximilian P. Lau Alexandra M. Linz Eric E. Roden Katherine D. McMahon
author_facet	Shaomei He Maximilian P. Lau Alexandra M. Linz Eric E. Roden Katherine D. McMahon
author_sort	Shaomei He
title	Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes
title_short	Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes
title_full	Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes
title_fullStr	Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes
title_full_unstemmed	Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes
title_sort	extracellular electron transfer may be an overlooked contribution to pelagic respiration in humic-rich freshwater lakes
publisher	American Society for Microbiology
publishDate	2019
url	https://doaj.org/article/6bfbef21714142578feacede273af345
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Extracellular Electron Transfer May Be an Overlooked Contribution to Pelagic Respiration in Humic-Rich Freshwater Lakes

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