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Land-use alters the temperature response of microbial carbon-use efficiency in soils – a consumption-based approach.
- Source :
-
Soil Biology & Biochemistry . Jan2020, Vol. 140, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
-
Abstract
- Soil organic carbon (SOC) is a substantial source of atmospheric CO 2 , but also a large cause of uncertainties in Earth-system models. A principal control on soil CO 2 release is the carbon-use efficiency (CUE) of microbial communities, which partitions the carbon (C) allocation between biosynthetic stabilization and CO 2 respiration during SOC decomposition. In Earth-system models, CUE is commonly considered as a constant, although it should be susceptible to environmental factors such as temperature. We explored CUE across a set of land-uses and temperatures, and we show the hitherto neglected phenomenon that land-use can alter the temperature response of CUE. In arable soils, CUE was constant over a temperature range between 5 and 20 °C, but it decreased with temperature in ley farming, grassland, and forest soils at temperatures above 12.5 °C. The decrease in CUE was strongest for forest soils. Implementing our findings into a soil-C model revealed substantial differences in projected SOC losses: Assuming an increase of mean annual temperature of 2 or 4 °C, soils were projected to lose up to 6 or 15% of their current SOC, respectively, until they reach a new steady-state. These projections varied among land-uses. Our findings confront the current representation of CUE in global C models and challenges C sequestration strategies based on land-use changes, because land-uses such as e.g. forest ecosystems with current high C storage may lose substantially more C than agricultural soils due to strong declines of CUE. Image 1 • Temperature responses of carbon-use efficiency (CUE) differed across land-uses. • CUE decreased strongly in ley farming, grassland, and forest soils beyond 12.5 °C. • Land-use specific CUE temperature responses have profound impact on SOC projection. • Novel consumption-based thermodynamic approach ensures similar microbial workloads. • Microbial community composition was not a major driver of differences in CUE. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00380717
- Volume :
- 140
- Database :
- Academic Search Index
- Journal :
- Soil Biology & Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 140978308
- Full Text :
- https://doi.org/10.1016/j.soilbio.2019.107639