Evaluation of the 18O-H2O incubation method for measurement of soil microbial carbon use efficiency. (June 2020)

• Record Type: Journal Article
• Authors: Qu, Lingrui; Wang, Chao; Bai, Edith
• Is Part Of: Soil biology and biochemistry. Volume 145(2020)
• Publication Date: 2020-06
• Subjects: Oxygen isotope -- Growth rate -- Carbon use efficiency -- Microbial turnover rate -- Soil carbon cycles; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2020.107802
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: The 18 O-labelled water approach has been widely used to estimate microbial carbon use efficiency (CUE). However, this approach assumes that oxygen in microbial DNA synthesis is 100% from water while this assumption has not been tested. We tested this assumption using 18 O-labelled glucose and 18 O-labelled water to see their contributions to the oxygen in microbial DNA synthesis. Results showed microbes used less than 8.3% glucose-oxygen and more than 91.7% water-oxygen for their DNA synthesis. The 18 O-labelled water method for estimation of CUE has proven to be reliable under low enrichment of 18 O in soil water. We suggest to use a correction factor (i.e., 1.1 in this study) to account for oxygen incorporated into DNA from other sources than water. Highlights: The best incubation time for 18 O-H2 O approach to study microbial CUE was 48 h. Soil microbes used more than 90% water oxygen for their new DNA synthesis. A conversion factor of 1.1 was found for CUE estimation for our studied soil.