Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands

[Image: see text] In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO(2) and CH(4). Duri...

Descripción completa

Detalles Bibliográficos
Autores principales: Patzner, Monique S., Kainz, Nora, Lundin, Erik, Barczok, Maximilian, Smith, Chelsea, Herndon, Elizabeth, Kinsman-Costello, Lauren, Fischer, Stefan, Straub, Daniel, Kleindienst, Sara, Kappler, Andreas, Bryce, Casey
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9097474/
https://www.ncbi.nlm.nih.gov/pubmed/35290040
http://dx.doi.org/10.1021/acs.est.1c06937
_version_ 1784706184965521408
author Patzner, Monique S.
Kainz, Nora
Lundin, Erik
Barczok, Maximilian
Smith, Chelsea
Herndon, Elizabeth
Kinsman-Costello, Lauren
Fischer, Stefan
Straub, Daniel
Kleindienst, Sara
Kappler, Andreas
Bryce, Casey
author_facet Patzner, Monique S.
Kainz, Nora
Lundin, Erik
Barczok, Maximilian
Smith, Chelsea
Herndon, Elizabeth
Kinsman-Costello, Lauren
Fischer, Stefan
Straub, Daniel
Kleindienst, Sara
Kappler, Andreas
Bryce, Casey
author_sort Patzner, Monique S.
collection PubMed
description [Image: see text] In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO(2) and CH(4). During the summer, shifts in runoff and soil moisture influence redox conditions and therefore the balance of Fe oxidation and reduction. Whether reactive iron minerals could act as a stable sink for carbon or whether they are continuously dissolved and reprecipitated during redox shifts remains unknown. We deployed bags of synthetic ferrihydrite (FH)-coated sand in the active layer along a permafrost thaw gradient in Stordalen mire (Abisko, Sweden) over the summer (June to September) to capture changes in redox conditions and quantify the formation and dissolution of reactive Fe(III) (oxyhydr)oxides. We found that the bags accumulated Fe(III) under constant oxic conditions in areas overlying intact permafrost over the full summer season. In contrast, in fully thawed areas, conditions were continuously anoxic, and by late summer, 50.4 ± 12.8% of the original Fe(III) (oxyhydr)oxides were lost via dissolution. Periodic redox shifts (from 0 to +300 mV) were observed over the summer season in the partially thawed areas. This resulted in the dissolution and loss of 47.2 ± 20.3% of initial Fe(III) (oxyhydr)oxides when conditions are wetter and more reduced, and new formation of Fe(III) minerals (33.7 ± 8.6% gain in comparison to initial Fe) in the late summer under more dry and oxic conditions, which also led to the sequestration of Fe-bound organic carbon. Our data suggest that there is seasonal turnover of iron minerals in partially thawed permafrost peatlands, but that a fraction of the Fe pool remains stable even under continuously anoxic conditions.
format Online
Article
Text
id pubmed-9097474
institution National Center for Biotechnology Information
language English
publishDate 2022
publisher American Chemical Society
record_format MEDLINE/PubMed
spelling pubmed-90974742022-05-13 Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands Patzner, Monique S. Kainz, Nora Lundin, Erik Barczok, Maximilian Smith, Chelsea Herndon, Elizabeth Kinsman-Costello, Lauren Fischer, Stefan Straub, Daniel Kleindienst, Sara Kappler, Andreas Bryce, Casey Environ Sci Technol [Image: see text] In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO(2) and CH(4). During the summer, shifts in runoff and soil moisture influence redox conditions and therefore the balance of Fe oxidation and reduction. Whether reactive iron minerals could act as a stable sink for carbon or whether they are continuously dissolved and reprecipitated during redox shifts remains unknown. We deployed bags of synthetic ferrihydrite (FH)-coated sand in the active layer along a permafrost thaw gradient in Stordalen mire (Abisko, Sweden) over the summer (June to September) to capture changes in redox conditions and quantify the formation and dissolution of reactive Fe(III) (oxyhydr)oxides. We found that the bags accumulated Fe(III) under constant oxic conditions in areas overlying intact permafrost over the full summer season. In contrast, in fully thawed areas, conditions were continuously anoxic, and by late summer, 50.4 ± 12.8% of the original Fe(III) (oxyhydr)oxides were lost via dissolution. Periodic redox shifts (from 0 to +300 mV) were observed over the summer season in the partially thawed areas. This resulted in the dissolution and loss of 47.2 ± 20.3% of initial Fe(III) (oxyhydr)oxides when conditions are wetter and more reduced, and new formation of Fe(III) minerals (33.7 ± 8.6% gain in comparison to initial Fe) in the late summer under more dry and oxic conditions, which also led to the sequestration of Fe-bound organic carbon. Our data suggest that there is seasonal turnover of iron minerals in partially thawed permafrost peatlands, but that a fraction of the Fe pool remains stable even under continuously anoxic conditions. American Chemical Society 2022-03-15 2022-04-05 /pmc/articles/PMC9097474/ /pubmed/35290040 http://dx.doi.org/10.1021/acs.est.1c06937 Text en © 2022 American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Patzner, Monique S.
Kainz, Nora
Lundin, Erik
Barczok, Maximilian
Smith, Chelsea
Herndon, Elizabeth
Kinsman-Costello, Lauren
Fischer, Stefan
Straub, Daniel
Kleindienst, Sara
Kappler, Andreas
Bryce, Casey
Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
title Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
title_full Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
title_fullStr Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
title_full_unstemmed Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
title_short Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
title_sort seasonal fluctuations in iron cycling in thawing permafrost peatlands
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9097474/
https://www.ncbi.nlm.nih.gov/pubmed/35290040
http://dx.doi.org/10.1021/acs.est.1c06937
work_keys_str_mv AT patznermoniques seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT kainznora seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT lundinerik seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT barczokmaximilian seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT smithchelsea seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT herndonelizabeth seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT kinsmancostellolauren seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT fischerstefan seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT straubdaniel seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT kleindienstsara seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT kapplerandreas seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands
AT brycecasey seasonalfluctuationsinironcyclinginthawingpermafrostpeatlands