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Temperature Effects on Kinetics of Microbial Respiration and Net Nitrogen and Sulfur Mineralization
Author(s) -
MacDonald Neil W.,
Zak Donald R.,
Pregitzer Kurt S.
Publication year - 1995
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/sssaj1995.03615995005900010036x
Subject(s) - mineralization (soil science) , respiration , chemistry , soil water , nitrogen cycle , environmental chemistry , soil respiration , nitrogen , ecosystem , sulfur , soil science , ecology , environmental science , botany , biology , organic chemistry
Global climate change may impact the cycling of C, N, and S in forest ecosystems because increased soil temperatures could alter rates of microbially mediated processes. We studied the effects of temperature on microbial respiration and net N and S mineralization in surface soils from four northern hardwood forests in the Great Lakes region. Soil samples were incubated in the laboratory at five temperatures (5, 10, 15, 20, and 25°C) for 32 wk. Headspace gas was analyzed for CO 2 ‐C at 2‐wk intervals, and soils were extracted to determine inorganic N and S. Cumulative respired C and mineralized N and S increased with temperature at all sites and were strongly related ( r 2 = 0.67 to 0.90, significant at P = 0.001) to an interaction between temperature and soil organic C. Production of respired C and mineralized N was closely fit by first‐order kinetic models ( r 2 ≥ 0.94, P = 0.001), whereas mineralized S was best described by zero‐order kinetics. Contrary to common assumptions, rate constants estimated from the first‐order models were not consistently related to temperature, but apparent pool sizes of C and N were highly temperature dependent. Temperature effects on microbial respiration could not be accurately predicted using temperature‐adjusted rate constants combined with a constant pool size of labile C. Results suggest that rates of microbial respiration and the mineralization of N and S may be related to a temperature‐dependent constraint on microbial access to substrate pools. Simulation models should rely on a thorough understanding of the biological basis underlying microbially mediated C, N, and S transformations in soil.