Abstract
Microbial carbon use efficiency (CUE) is a critical regulator of soil organic matter dynamics and terrestrial carbon fluxes, with strong implications for soil biogeochemistry models. While ecologists increasingly appreciate the importance of CUE, its core concepts remain ambiguous: terminology is inconsistent and confusing, methods capture variable temporal and spatial scales, and the significance of many fundamental drivers remains inconclusive. Here we outline the processes underlying microbial efficiency and propose a conceptual framework that structures the definition of CUE according to increasingly broad temporal and spatial drivers where (1) CUE P reflects population-scale carbon use efficiency of microbes governed by species-specific metabolic and thermodynamic constraints, (2) CUE C defines community-scale microbial efficiency as gross biomass production per unit substrate taken up over short time scales, largely excluding recycling of microbial necromass and exudates, and (3) CUE E reflects the ecosystem-scale efficiency of net microbial biomass production (growth) per unit substrate taken up as iterative breakdown and recycling of microbial products occurs. CUEE integrates all internal and extracellular constraints on CUE and hence embodies an ecosystem perspective that fully captures all drivers of microbial biomass synthesis and decay. These three definitions are distinct yet complementary, capturing the capacity for carbon storage in microbial biomass across different ecological scales. By unifying the existing concepts and terminology underlying microbial efficiency, our framework enhances data interpretation and theoretical advances.
Highlights
IntroductionThe efficiency with which microorganisms convert available organic substrates into stable, biosynthesized products (broadly defined as ‘carbon use efficiency’—CUE) is a critical step in ecosystem carbon cycling
The efficiency with which microorganisms convert available organic substrates into stable, biosynthesized products is a critical step in ecosystem carbon cycling
Numerous approaches to measuring community-scale carbon use efficiency (CUEC) exist using a ratio of biomass production and substrate uptake, where uptake can be approximated by the sum of production and respiration (Manzoni et al 2012)
Summary
The efficiency with which microorganisms convert available organic substrates into stable, biosynthesized products (broadly defined as ‘carbon use efficiency’—CUE) is a critical step in ecosystem carbon cycling. CUE is an important concept for understanding the future trajectory of soil-climate feedbacks, recognition of which has led to recent reviews of the topic (Manzoni et al 2012; Sinsabaugh et al 2013), application in ecosystem models (Wang et al 2013; Allison 2014; Wieder et al 2014), and the development of new methods to estimate microbial efficiency in environmental samples (Blazewicz and Schwartz 2011; Dijkstra et al 2011b; Herrmann et al 2014) Progress in this field is hampered by chronic issues symptomatic of a divide among research approaches and disciplinespecific terminologies. Methodology Total respiratory losses, as measured by CO2 production or O2 demandg,h
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
