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Microbial Utilization of Carbon‐14‐Glucose in Aerobic vs. Anaerobic Denitrifying Soils
Author(s) -
Parsons Laura L.,
Smith M. Scott
Publication year - 1989
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1989.03615995005300040016x
Subject(s) - denitrifying bacteria , anaerobic exercise , loam , soil water , chemistry , environmental chemistry , agronomy , denitrification , ecology , nitrogen , biology , physiology , organic chemistry
In order to better characterize the behavior of denitrifying bacteria in soil and their effect on cycling of C and N, the rate of consumption and the extent of microbial assimilation of glucose were compared in aerobic and anaerobic denitrifying soils. Three soils (Bruno, a Udifluvent; Maury silt loam, and Paleudalf; and Lanton, a Haplaquoll) were amended with 14 C‐glucose and excess NO ‐ 3 , then incubated for 3 to 7 d in air or anaerobically. Transient accumulations of soluble, nonglucose intermediates occurred in both aerobic and anaerobic soils. Aerobic substrate consumption rates were greater than anaerobic denitrifying substrate consumption rates. Anaerobic substrate consumption rate varied among soils more than aerobic rates, but the ratio of aerobic to anaerobic rates for a sample was not related to the presumed propensity of that soil type to denitrify. When all labelled glucose had been depleted, 8 to 10% more of the label had been mineralized to CO 2 in the anaerobic than in aerobic incubations, suggesting lower efficiency of assimilation under denitrifying conditions. However, the effect of aerobic vs. denitrifying respiration on assimilation efficiency was small relative to differences among soil samples and the effects of substrate‐to‐soil ratio.