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Carbon Limitation Leads to Thermodynamic Regulation of Aerobic Metabolism

Authors :
Jason Toyoda
Rosalie K. Chu
Lupita Renteria
Amy E. Goldman
James C. Stegen
V. A. Garayburu-Caruso
Whitney L. Garcia
Emily B. Graham
Charles T. Resch
Jacqueline Wells
Hyun-Seob Song
Source :
Environmental Science & Technology Letters. 7:517-524
Publication Year :
2020
Publisher :
American Chemical Society (ACS), 2020.

Abstract

Organic matter (OM) metabolism in freshwater ecosystems is a critical source of uncertainty in global biogeochemical cycles, yet aquatic OM cycling remains poorly understood. Here, we present the first work to explicitly test OM thermodynamics as a key regulator of aerobic respiration, challenging long-held beliefs that organic carbon and oxygen concentrations are the primary determinants of respiration rates. We pair controlled microcosm experiments with ultrahigh-resolution OM characterization to demonstrate a clear relationship between OM thermodynamic favorability and aerobic respiration under carbon limitation. We also demonstrate a shift in the regulation of aerobic respiration from OM thermodynamics to nitrogen content when carbon is in excess, highlighting a central role for OM thermodynamics in aquatic biogeochemical cycling particularly in carbon-limited ecosystems. Our work therefore illuminates a structural gap in aquatic biogeochemical models and presents a new paradigm in which OM thermodynamics and nitrogen content interactively govern aerobic respiration.

Details

ISSN :
23288930
Volume :
7
Database :
OpenAIRE
Journal :
Environmental Science & Technology Letters
Accession number :
edsair.doi.dedup.....52c6dddde0aff2c0d1e63836bb63fb60
Full Text :
https://doi.org/10.1021/acs.estlett.0c00258