Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland
Climate change dramatically impacts Arctic and subarctic regions, inducing shifts in wetland nutrient regimes as a consequence of thawing permafrost. Altered hydrological regimes may drive changes in the dynamics of microbial mercury (Hg) methylation and bioavailability. Important knowledge gaps rem...
Published in: | Frontiers in Microbiology |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Frontiers Media S.A.
2021
|
Subjects: | |
Online Access: | https://doi.org/10.3389/fmicb.2021.741523 https://doaj.org/article/216c69c6113a4a60a025661860bcd1d7 |
id |
ftdoajarticles:oai:doaj.org/article:216c69c6113a4a60a025661860bcd1d7 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:216c69c6113a4a60a025661860bcd1d7 2023-05-15T15:16:41+02:00 Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland Spencer Roth Brett A. Poulin Zofia Baumann Xiao Liu Lin Zhang David P. Krabbenhoft Mark E. Hines Jeffra K. Schaefer Tamar Barkay 2021-10-01T00:00:00Z https://doi.org/10.3389/fmicb.2021.741523 https://doaj.org/article/216c69c6113a4a60a025661860bcd1d7 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/fmicb.2021.741523/full https://doaj.org/toc/1664-302X 1664-302X doi:10.3389/fmicb.2021.741523 https://doaj.org/article/216c69c6113a4a60a025661860bcd1d7 Frontiers in Microbiology, Vol 12 (2021) climate change peatland hgcA syntrophy mercury methylation Microbiology QR1-502 article 2021 ftdoajarticles https://doi.org/10.3389/fmicb.2021.741523 2022-12-31T07:55:36Z Climate change dramatically impacts Arctic and subarctic regions, inducing shifts in wetland nutrient regimes as a consequence of thawing permafrost. Altered hydrological regimes may drive changes in the dynamics of microbial mercury (Hg) methylation and bioavailability. Important knowledge gaps remain on the contribution of specific microbial groups to methylmercury (MeHg) production in wetlands of various trophic status. Here, we measured aqueous chemistry, potential methylation rates (kmeth), volatile fatty acid (VFA) dynamics in peat-soil incubations, and genetic potential for Hg methylation across a groundwater-driven nutrient gradient in an interior Alaskan fen. We tested the hypotheses that (1) nutrient inputs will result in increased methylation potentials, and (2) syntrophic interactions contribute to methylation in subarctic wetlands. We observed that concentrations of nutrients, total Hg, and MeHg, abundance of hgcA genes, and rates of methylation in peat incubations (kmeth) were highest near the groundwater input and declined downgradient. hgcA sequences near the input were closely related to those from sulfate-reducing bacteria (SRB), methanogens, and syntrophs. Hg methylation in peat incubations collected near the input source (FPF2) were impacted by the addition of sulfate and some metabolic inhibitors while those down-gradient (FPF5) were not. Sulfate amendment to FPF2 incubations had higher kmeth relative to unamended controls despite no effect on kmeth from addition of the sulfate reduction inhibitor molybdate. The addition of the methanogenic inhibitor BES (25 mM) led to the accumulation of VFAs, but unlike molybdate, it did not affect Hg methylation rates. Rather, the concurrent additions of BES and molybdate significantly decreased kmeth, suggesting a role for interactions between SRB and methanogens in Hg methylation. The reduction in kmeth with combined addition of BES and molybdate, and accumulation of VFA in peat incubations containing BES, and a high abundance of syntroph-related hgcA ... Article in Journal/Newspaper Arctic Climate change permafrost Subarctic Directory of Open Access Journals: DOAJ Articles Arctic Frontiers in Microbiology 12 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
climate change peatland hgcA syntrophy mercury methylation Microbiology QR1-502 |
spellingShingle |
climate change peatland hgcA syntrophy mercury methylation Microbiology QR1-502 Spencer Roth Brett A. Poulin Zofia Baumann Xiao Liu Lin Zhang David P. Krabbenhoft Mark E. Hines Jeffra K. Schaefer Tamar Barkay Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland |
topic_facet |
climate change peatland hgcA syntrophy mercury methylation Microbiology QR1-502 |
description |
Climate change dramatically impacts Arctic and subarctic regions, inducing shifts in wetland nutrient regimes as a consequence of thawing permafrost. Altered hydrological regimes may drive changes in the dynamics of microbial mercury (Hg) methylation and bioavailability. Important knowledge gaps remain on the contribution of specific microbial groups to methylmercury (MeHg) production in wetlands of various trophic status. Here, we measured aqueous chemistry, potential methylation rates (kmeth), volatile fatty acid (VFA) dynamics in peat-soil incubations, and genetic potential for Hg methylation across a groundwater-driven nutrient gradient in an interior Alaskan fen. We tested the hypotheses that (1) nutrient inputs will result in increased methylation potentials, and (2) syntrophic interactions contribute to methylation in subarctic wetlands. We observed that concentrations of nutrients, total Hg, and MeHg, abundance of hgcA genes, and rates of methylation in peat incubations (kmeth) were highest near the groundwater input and declined downgradient. hgcA sequences near the input were closely related to those from sulfate-reducing bacteria (SRB), methanogens, and syntrophs. Hg methylation in peat incubations collected near the input source (FPF2) were impacted by the addition of sulfate and some metabolic inhibitors while those down-gradient (FPF5) were not. Sulfate amendment to FPF2 incubations had higher kmeth relative to unamended controls despite no effect on kmeth from addition of the sulfate reduction inhibitor molybdate. The addition of the methanogenic inhibitor BES (25 mM) led to the accumulation of VFAs, but unlike molybdate, it did not affect Hg methylation rates. Rather, the concurrent additions of BES and molybdate significantly decreased kmeth, suggesting a role for interactions between SRB and methanogens in Hg methylation. The reduction in kmeth with combined addition of BES and molybdate, and accumulation of VFA in peat incubations containing BES, and a high abundance of syntroph-related hgcA ... |
format |
Article in Journal/Newspaper |
author |
Spencer Roth Brett A. Poulin Zofia Baumann Xiao Liu Lin Zhang David P. Krabbenhoft Mark E. Hines Jeffra K. Schaefer Tamar Barkay |
author_facet |
Spencer Roth Brett A. Poulin Zofia Baumann Xiao Liu Lin Zhang David P. Krabbenhoft Mark E. Hines Jeffra K. Schaefer Tamar Barkay |
author_sort |
Spencer Roth |
title |
Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland |
title_short |
Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland |
title_full |
Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland |
title_fullStr |
Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland |
title_full_unstemmed |
Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland |
title_sort |
nutrient inputs stimulate mercury methylation by syntrophs in a subarctic peatland |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/fmicb.2021.741523 https://doaj.org/article/216c69c6113a4a60a025661860bcd1d7 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change permafrost Subarctic |
genre_facet |
Arctic Climate change permafrost Subarctic |
op_source |
Frontiers in Microbiology, Vol 12 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/fmicb.2021.741523/full https://doaj.org/toc/1664-302X 1664-302X doi:10.3389/fmicb.2021.741523 https://doaj.org/article/216c69c6113a4a60a025661860bcd1d7 |
op_doi |
https://doi.org/10.3389/fmicb.2021.741523 |
container_title |
Frontiers in Microbiology |
container_volume |
12 |
_version_ |
1766346977797210112 |