CO_2 and O_2 respiration kinetics in hydrocarbon contaminated soils amended with organic carbon sources used to determine catabolic diversity

摘要

Multiple substrate induced respiration (MSIR) assays which assess the response of soils to carbon source amendment are effective approaches to determine catabolic diversity of soils. Many assays are based on a single short term (<6 h) time point measurement and usually limited to CO_2 production only. However, repeated measurements of both CO_2 and O_2 simultaneously can provide additional valuable information. In this study, a MSIR assay involving eight carbon sources was applied to three hydrocarbon contaminated soils using continuous CO_2 and O_2 respiration measurements. Based on cumulative CO_2 and O_2 measurements at 4, 24 and 120 h, the soils were found to be distinct in terms of their catabolic diversity. Most noteworthy, however, was the response to the addition of maleic acid which provided strong evidence of abiotic CO_2 efflux to be the overriding process, raising questions about the interpretation of CO_2 only responses from organic acid addition in MSIR assays.