Authors: Zachary L Rinkes Jared L DeForest A Stuart Grandy Daryl L Moorhead Michael N Weintraub
Publish Date: 2013/06/05
Volume: 117, Issue: 1, Pages: 153-168
Abstract
With global change expected to alter aspects of the carbon C cycle empirical data describing how microorganisms function in different environmental conditions are needed to increase predictive capabilities of microbiallydriven decomposition models Given the importance of accelerated C fluxes during early decay in C cycling we characterized how varying litter qualities maple vs oak and sizes ground vs 025 cm2 vs 1 cm2 and contrasting soils sandy vs loamy altered microbial biomasscarbon and community structure respiration enzyme activities and inorganic nutrients over the initial 2 weeks of decomposition Our hypotheses were 1 mixing ground maple with loam should result in a quicker more prolonged respiration response than other treatments and 2 “priming” or substratestimulated soil organic matter turnover should be minimal over the first few days due to soluble C substrate uptake Respiration peaks biomass increases nutrient immobilization low enzyme activities and minimal priming occurred in all treatments over the first 72 h These general features suggest soluble C compounds are degraded before polymeric substrates regardless of litter size or type or soil Ground litter addition to the high C and microbial biomass loam resulted in a more prolonged respiration peak than the poorly aggregated sand Priming was greater in loam than the C limited sandy soil after the first 72 h likely due to cometabolism of labile and recalcitrant substrates We conclude that the general features of early decay are widespread and predictable yet differences in litter and soil characteristics influence the temporal pattern and magnitude of C fluxThis research was supported by the NSF Ecosystems Program Grant 0918718 For field and laboratory assistance we thank Mallory Ladd Ryan Monnin Steve Solomon Heather Thoman Logan Thornsberry and Megan Wenzel We are also grateful to Jason Witter for assistance in freezedrying samples for PLFA analysis For help with CN analysis we thank Doug Sturtz Russ Friederich and Jonathan Frantz from the USDA ARS at the University of Toledo We also thank two anonymous reviewers whose suggestions greatly improved this work
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