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https://doi.org/10.5194/egusphere-2024-3636
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/egusphere-2024-3636
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
03 Dec 2024
| 03 Dec 2024
Status: this preprint is open for discussion.
Brief Communications: Stream Microbes Preferentially Utilize Young Carbon within the Ancient Bulk Glacier Dissolved Organic Carbon Pool
Abstract. Glaciers export ancient, bioavailable dissolved organic carbon (DOC). Yet, the sources of organic carbon (OC) underpinning bioavailability are poorly constrained. We assessed the isotopic composition of respired OC from bioincubations of glacier DOC. Relative to DOC, respired OC was younger (+4,350 – 8,940 yBP) and 13C enriched (+9.2 – 12.2 ‰), consistent with utilization of an in situ produced microbial carbon source. Molecular-level analyses suggest respired OC was associated with the aliphatic-rich portion of the dissolved organic matter pool. These findings provide direct evidence that a hidden pool of young OC may underpin the high bioavailability of ancient glacier DOC.
How to cite. Holt, A. D., Fellman, J. B., Kellerman, A. M., Hood, E., Bosman, S. H., McKenna, A. M., Chanton, J. P., and Spencer, R. G. M.: Brief Communications: Stream Microbes Preferentially Utilize Young Carbon within the Ancient Bulk Glacier Dissolved Organic Carbon Pool, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-3636, 2024.
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Amy D. Holt
CORRESPONDING AUTHOR
National High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
Jason B. Fellman
Program on the Environment and Alaska Coastal Rainforest Center, University of Alaska Southeast, Juneau, AK, 99801, USA
Anne M. Kellerman
National High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
Eran Hood
Program on the Environment and Alaska Coastal Rainforest Center, University of Alaska Southeast, Juneau, AK, 99801, USA
Samantha H. Bosman
National High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
Amy M. McKenna
Ion Cyclotron Resonance Facility, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310-4005, USA
Department of Soil Crop Sciences, Colorado State University, Fort Collins, Colorado 80523-1170, United States
Jeffery P. Chanton
National High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
Robert G. M. Spencer
National High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
Short summary
Glacier runoff is a source of old, bioavailable dissolved organic carbon (DOC) to downstream ecosystems. The DOC pool is composed of material of various origin, chemical character, age and bioavailability. Using bioincubation experiments we show glacier DOC bioavailability is driven by a young source, rather than ancient material which comprises the majority of the glacier carbon pool. This young, bioavailable fraction could currently be a critical carbon subsidy for recipient food webs.
Glacier runoff is a source of old, bioavailable dissolved organic carbon (DOC) to downstream...