Enzyme stoichiometry indicates the variation of microbial nutrient requirements at different soil depths in subtropical forests

Abstract

2Soil extracellular enzyme activities and associated enzymatic stoichiometry are considered 3 indicators to nutrients availability and microbial substrate limitation. However, many of current studies 4 have been focusing on upper most soil layer with a single enzyme as represent, leading to critical 5 uncertainties in understanding the nutrient availability in deeper soils. In this study, we investigated 6 C-, N-and P-acquiring enzyme activities and microbial C, N and P limitation across a range of soil 7 layers (0 -10, 10 -20, 20 -40 and 40 -60 cm) in a natural secondary evergreen broad-leaved forest 8 and a Chinese fir (Cunninghamia lanceolata) plantation forest in subtropical China. Our results 9 showed that the two typical subtropical forests are commonly co-limited by C and P at all soil depths, 10 but not N. The study found that microbial C and P limitation fluctuated along soil depth, and that 11 higher N was demanded by microbes in soil under 20 cm in the two forests. Our results highlight the 12 asymmetrical patterns of microbial nutrient limitation along the whole soil profile, and provide 13 important information in understanding nutrient limitations in deeper soils. It is feasible to explicitly 14 incorporate this vertical asymmetrical nutrient limitation patterns into future research priority.15 16

Microbial properties in tropical montane forest soils developed from contrasting parent material—An incubation experiment

“…A similar observation was made by Liu et al. (2020) in subtropical soils of China. Overall, under laboratory incubation conditions in which all soils were subjected to standardized moisture, oxygen, and temperature, we found a high proportion of potentially labile C in tropical subsoils (Figure 1e−h).…”

“…Overall, explanatory variables (i.e., rPCs) did not explain the variance in microbial investment in C and P acquisition to a greater extent (Table 2). This indicates that microbial resource acquisition is complex and could strongly depend on other factors that were not accounted for in this study, such as microbial physiology, substrate stoichiometry, and microbial community composition (Cui et al., 2019; Liu et al., 2020; Stone et al., 2014).…”

Herbivores stimulate respiration from labile and recalcitrant soil carbon pools in grasslands of Yellowstone National Park

“…Grazing increases labile C inputs in YNP (Hamilton III & Frank, 2001; Hamilton III, Frank, Hinchey, & Murray, 2008) which may have stimulated soil microbial decomposition of relatively recalcitrant C (Frank et al, 2002; Vestergård, Reinsch, Bengtson, Ambus, & Christensen, 2016; Wilson et al, 2018). Second, progressive changes in microbial community composition and extracellular enzymes could contribute to the degradation of recalcitrant C pool (Liu, Chen, Chen, Guo, & Li, 2020; Mueller et al, 2017; Stark et al, 2015). Third, herbivores may have increased the degradation of the recalcitrant soil C pool by their dung and urine inputs (Blagodatsky et al, 2010; Piñeiro, Paruelo, Oesterheld, & Jobbágy, 2010) or trampling and fragmenting organic material (Kauffman, Thorpe, & Brookshire, 2004).…”

Long‐term nitrogen loading alleviates phosphorus limitation in terrestrial ecosystems

“…Plants and soil microorganisms preferentially invest metabolic resources to acquire nutrients that limit their growth (Bragg, 2012; Johnson, Wilson, Bowker, Wilson, & Miller, 2010; Marklein & Houlton, 2012). Soil phosphatases are enzymes produced by both plants and soil microorganisms to catalyze the hydrolysis of ester‐phosphate bonds and phosphoric acid anhydrides, releasing orthophosphate that can be taken up across living cell membranes (Liu, Chen, Chen, Guo, & Li, 2020; Margalef et al., 2017; Vance, Uhde Stone, & Allan, 2003). The production of extracellular phosphatases is generally assumed to indicate P limitation of both plant and microbial growth (Jian et al., 2016; Marklein & Houlton, 2012; Vitousek, Porder, Houlton, & Chadwick, 2010).…”