Title: Sequential Abiotic-Biotic Processes Drive Organic Carbon Transformation in Peat Bogs

Abstract

Abstract Peatlands, which store one third of the terrestrial carbon (C), are subject to large disturbances under a changing climate. It is crucial to understand how microbial and physiochemical factors affect the vulnerability of these large C stores to predict climate‐induced greenhouse gas fluxes. Here, we used a combination of mass spectrometry and spectroscopy techniques, to understand sequential biotic and abiotic degradation pathways of Sphagnum fallax leachate in an anaerobic incubation experiment, in the presence and absence of microorganisms. Removal of microorganisms was carried out by passing aqueous samples through 0.2‐µm filters. Our results revealed that S. fallax leachate degradation by abiotic reactions is a significant contributor to CO ₂ production. Further, abiotic factors, such as low pH, are responsible for partial dissolved organic carbon (DOC) degradation that produces bioavailable compounds that shift microbial metabolic pathways and stimulate respiration in peat bogs. Acid‐catalyzed hydrolysis of Sphagnum ‐ produced glycosides can provide the microbial communities with glucose and stimulate microbial respiration of DOC to CO ₂ . These results, while unique to peatlands, demonstrate the importance and underscore the complexity of sequential abiotic and biotic processes on C cycling in peat bogs. It is therefore crucial to incorporate abiotic degradation andmore » sequential below‐ground biotic and abiotic interactions into climate models for a better prediction of the influence of climate change on DOC stability in peatlands. These findings might not be representative of other ecosystems with different environmental conditions including mineral‐rich peatlands and plant matter in surface peat horizons that comprise discrete microbial populations, and DOC composition.« less

Authors:

Fudyma, Jane D.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8834-9044"

Toyoda, Jason G. ^[2]; Chu, Rosalie K. ^[2]; Weitz, Karl K. ^[2]; Heyman, Heino M.  ^[3];

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Eder, Elizabeth ^[2]; Hoyt, David W.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-2857-719X"

Gieschen, Hans  ^[4];

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• Search DOE PAGES for ORCID "0000-0003-3845-3921"

Graf Grachet, Nathalia  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5713-8065"

Wilson, Rachel M.  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-5770-9614"

Tfaily, Malak M.  ^[6]

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• Search DOE PAGES for ORCID "0000-0002-3036-2833"

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+ Show Author Affiliations

1. Univ. of Arizona, Tucson, AZ (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Bruker Daltonics Inc., Billercia, MA (United States)
4. Department of Environmental Science The University of Arizona Tucson AZ USA
5. Florida State Univ., Tallahassee, FL (United States)
6. Univ. of Arizona, Tucson, AZ (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)

Publication Date:

Fri Jan 29 00:00:00 EST 2021

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Sciences Laboratory (EMSL)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC)

OSTI Identifier:

1781660

Alternate Identifier(s):

OSTI ID: 1786687

Report Number(s):

PNNL-SA-160453
Journal ID: ISSN 2169-8953

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research. Biogeosciences

Additional Journal Information:

Journal Volume: 126; Journal Issue: 2; Journal ID: ISSN 2169-8953

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; abiotic; biotic; degradation pathways; mass spectrometry; metabolites; peat bogs