Abstract
To explore the question how litter and macrofauna feces respond to temperature and how respiration differs for litter with a different CN ratio, we compared the decomposition rates of leaf litter (Alnus glutinosa, Salix caprea, and Acer campestre) and isopod (Armadillidium vulgare) feces produced from the same litter in response to three constant (8, 16, and 24 °C) and one fluctuating (first week 8 °C, the other week 24 °C) temperatures in a 50 week laboratory experiment and in a field trial. Microbial respiration of litter with lower CN ratio (alder and willow) was significantly higher than respiration of feces, no significant difference was found for maple litter with higher CN ratio. This was supported by field litter bag experiments where alder and willow litter decomposed faster than feces but the opposite was true for maple litter. Litter respiration was significantly affected by temperature but feces respiration was not. Fluctuating temperature caused either lower or equal respiration as compared to mean constant temperature. The content of phenolics was significantly higher in intact litter in comparison with decomposed litter and feces, either fresh or decomposed. The CN ratio decreased as litter turned to feces in maple and alder litter but increased in willow litter. In conclusion, microbial respiration of both litter and feces were substantially affected by litter quality; the litter was more sensitive to temperature than feces.
Highlights
Soil contains three times more carbon (C) than the atmosphere
During the 50 week experiment, the microbial respiration of both litter and feces gradually decreased with time (Figure 1)
Carbon loss due to microbial respiration was significantly greater from litter than from A. vulgare feces (Figure 2; Table 1)
Summary
Soil contains three times more carbon (C) than the atmosphere. Carbon storage in terrestrial ecosystems depends on the balance between the gain from net primary production and the loss through decomposition [1,2,3]. Litter decomposition exhibits a critical function in the C budget of terrestrial ecosystems [4,5]. Increasing temperature directly accelerates metabolic and biochemical processes [8], accelerating decomposition rates as well. Different soils, in which organic matter is bound in different ways, show highly variable responses to temperature [5]. Ecological stoichiometry describes how macroelements C, nitrogen (N), phosphorus (P), and their ratios are critical for organisms to build biological structures and regulate physiological processes [9]. The relative abundance of C and nutrients in organic
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