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Increasing soil temperature has the potential to alter the activity of
the extracellular enzymes that mobilize nitrogen (N) from soil organic
matter (SOM) and ultimately the availability of N for primary
production. Proteolytic enzymes depolymerize N from proteinaceous
components of SOM into amino acids, and their activity is a principal
driver of...
Contexts in source publication
Context 1
... The apparent activation energy of the protein substrate ranged from 18 to 60 kJ mol À1 (Table 1). On average, protein pools in sugar maple soils had the highest E a and hemlock the lowest ( p < 0.05) (Table 1), though the species rankings varied subtly among the three sampling dates. ...
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... The apparent activation energy of the protein substrate ranged from 18 to 60 kJ mol À1 (Table 1). On average, protein pools in sugar maple soils had the highest E a and hemlock the lowest ( p < 0.05) (Table 1), though the species rankings varied subtly among the three sampling dates. Seasonally, there was a significant interaction between species and sam- pling date on E a (p < 0.005). ...
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... ash, hemlock, and beech soils, E a declined across the growing season, though significantly (p < 0.05) only in ash and beech. The opposite was observed in sugar maple soils; E a 's in August were significantly higher than those in June and April (p < 0.05) (Table 1). ...
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... was little effect of warming on summer rates of proteolytic activity because warming accelerated the decline in the temperature sensitivity of enzyme activity across the growing season (Figure 4). By contrast, warming increased proteolytic activity over the growing season in sugar maple and ash soil (Figures 3c-3d), because of their high temperature sensitivity throughout the growing season (Table 1). Across the year elevating temperature by 5°C stimulated proteolytic enzyme activity 19%-36% (Table 2), with the largest stimulation in ash and sugar maple soil and the smallest in hemlock soil. ...
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... There were large seasonal differences in the temper- ature sensitivity of proteolytic enzyme activity (Figure 2). Across species and sampling dates, the E a of proteolytic enzyme activity varied from 18 to 60 kJ mol À1 (Table 1 and Figure 2). This measure of temperature sensitivity is, on average (mean E a = 33.5 kJ mol À1 ), less than half the value reported for the temperature sensitivity of C mineralization [e.g., Fierer et al., 2006;Craine et al., 2010]. ...
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... An interaction between leaf litter chemistry and the dynamics of protein protection by SOM may explain the greater activation energy of proteolytic enzyme activity in AM compared to ECM soil (Table 1). In particular, AM litter inputs are dominated by hydrolysable tannin whereas ECM litter inputs are dominated by condensed tannin [Talbot and Finzi, 2008]. ...
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... both types of tannins have the ability to bind proteins, condensed tannins protect protein from decomposition to a much greater degree than hydrolysable tannins [Kraus et al., 2003b;Bowman et al., 2004], and condensed tannins also bind soil enzymes, reducing activity [Joanisse et al., 2007]. Thus in AM soils, the greater apparent temperature sensitivity of proteolytic enzyme activity may be fueled by a greater availability of weakly bound SOM protein (Table 1). This line of argu- mentation could also help explain the increase in proteolytic activity across the growing season in sugar maple soil, the only species to display this pattern (Table 1). ...
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... in AM soils, the greater apparent temperature sensitivity of proteolytic enzyme activity may be fueled by a greater availability of weakly bound SOM protein (Table 1). This line of argu- mentation could also help explain the increase in proteolytic activity across the growing season in sugar maple soil, the only species to display this pattern (Table 1). ...
Citations
... This was attributed to higher rates of SOC decomposition at higher temperatures. There are some differences in temperature sensitivity between different soil enzyme ecosystems [86]. Enzymatic activity may also be influenced by soil water concentrations by changing rates of substrate diffusion. ...
The aim of the study was to determine the impact that three cultivation systems—conventional till (CT), reduced till (RT), and strip-till one-pass (ST-OP)—had on the biological parameters of the soil and their relationships with organic matter properties in the row zone (R) and inter-row zone (IR). For this purpose, a long-term static field experiment was carried out, from which soil samples were taken from a depth of 0–20 cm and the following were determined: TOC; TN content and fractional composition of organic matter; activity of dehydrogenases (DEHs), catalase (CAT), alkaline (AlP), and acid phosphatase (AcP); and the abundances of heterotophic bacteria (B), filamentous fungi (F), actinobacteria (Ac), and cellulolytic microorganisms (Ce). Soil samples for biological parameter tests were collected in summer (July) and autumn (October). RT and ST-OP increase the content of TOC, TN, carbon, and nitrogen in the humic and fulvic acid fractions. For the studied groups of microorganisms, the conditions for development were least favourable under CT cultivation. The results show that in July, the activities of DEH and CAT were the highest in ST-OP, whereas in October, they were the highest under CT. AlP and AcP activity were markedly the highest under ST-OP in both months. Enzyme activity was significantly the highest in the IR zone. The results indicate that, of the calculated multiparametric indicators, (AlP/AcP, GMea, BIF, BA12, and TEI), BA12 is a sensitive biological indicator of soil quality.
... Notably, increased soil moisture has been shown to increase enzyme activity [50,51], but the average soil moisture at the time of sampling fell from 19.5% in 2021 to 14.0% in 2022, indicating that other factors were likely playing a role in the increase in BG in 2022 as compared to 2021. Temperature has been positively correlated to enzyme activity [51,52]. However, soils were sampled in late June and May of 2021 and 2022, respectively, and June was warmer than May (average maximum soil temperatures of 27.8 • C compared to 18.6 • C at a depth of 5 cm, respectively; Colorado State University-CoAgMet Station ftc03-CSU-ARDEC; available at: https://coagmet. ...
Management-intensive Grazing (MiG) has been proposed to sustainably intensify agroecosystems through careful management of livestock rotations on pastureland. However, there is little research on the soil health impacts of transitioning from irrigated cropland to irrigated MiG pasture with continuous livestock rotation. We analyzed ten soil health indicators using the Soil Management Assessment Framework (SMAF) to identify changes in nutrient status and soil physical, biological, and chemical health five to six years after converting irrigated cropland to irrigated pastureland under MiG. Significant improvements in biological soil health indicators and significant degradation in bulk density, a physical soil health indicator, were observed. Removal of tillage and increased organic matter inputs may have led to increases in β-glucosidase, microbial biomass carbon, and potentially mineralizable nitrogen, all of which are biological indicators of soil health. Conversely, trampling by grazing cattle has led to increased bulk density and, thus, a reduction in soil physical health. Nutrient status was relatively stable, with combined manure and fertilizer inputs leading to stabilized plant-available phosphorous (P) and increased potassium (K) soil concentrations. Although mixed effects on soil health were present, overall soil health did increase, and the MiG system appeared to have greater overall soil health as compared to results generated four to five years earlier. When utilizing MiG in irrigated pastures, balancing the deleterious effects of soil compaction with grazing needs to be considered to maintain long-term soil health.
... In the same month as the wildfire, the soil AAN content in the burned plots increased significantly due to the decomposition of a large number of nitrogenous organic compounds produced by the burning of aboveground plants [64]. In August, the soil AAN content dropped sharply by 49.0%, influenced by various factors, such as the elevated pH value [65], AAN mineralization [66][67][68], AAN leaching, and soil erosion. In October, the soil protease activity and AAN mineralization were limited by low temperatures [69], and AAN leaching was almost stagnated by reduced rainfall. ...
This study investigates the evolution of soil nitrogen (N) contents and forms along a 17-year wildfire chronosequence in the Daxing’an Mountains. Surface soil and subsoil samples were collected during different recovery periods after wildfires. Then, the mineral N (i.e., NH4+-N and NO3−-N) and amino acid-N (AAN) contents in the soil extracts were measured and used to calculate the different ratios as indicators of the N forms. The results showed that the NH4+-N, NO3−-N, and AAN contents increased immediately after the wildfire. With vegetation restoration, the NH4+-N and NO3−-N contents became similar to those of unburned forests nine years and two months after the wildfire, respectively. The AAN content was mostly recovered one year post-fire. The wildfire did not lead to substantial changes in the mineral N form, but the ratio significantly increased and recovered after nine years. The soil available N form was altered by wildfires. After the wildfire, the dominant available N form changed from equivalent AAN and mineral N to a predominance of AAN in the growing season, and the predominance of AAN decreased to varying degrees in the non-growing season. With the recovery of the white birch and Dahurian larch, AAN again became the dominant N form, but the predominance of AAN was low before the freeze-up. Our study demonstrates that wildfires directly affect the soil N contents and forms, and such effects could be diminished by the restoration of the soil environment and vegetation over time.
... Soil substrate quality could affect the activation energy of extracellular enzymes, thus, modifying the sensitivity of soil EEAs to warming. To acquire energy and nutrients, soil microorganisms usually produce extracellular enzymes with higher activation energy to decompose complex SOM (Brzostek and Finzi, 2012). ...
Extracellular enzymes play central roles in the biogeochemical cycles in wetland ecosystems. Their activities are strongly impacted by hydrothermal conditions. Under the ongoing global change, many studies reported the individual effects of flooding and warming on soil extracellular enzyme activities, however, few researches investigated their interactive effects. Therefore, the current study aims to determine the responses of extracellular enzyme activities to warming in wetland soils under divergent flooding regimes. We investigated the temperature sensitivity of seven extracellular enzymes related to carbon (α-glucosidase, AG; β-glucosidase, BG; cellobiohydrolase, CBH; β-xylosidase, XYL), nitrogen (β-N-acetyl -glucosaminidase, NAG; leucine aminopeptidase, LAP), and phosphorus (Phosphatase, PHOS) cycling along the flooding duration gradient in a lakeshore wetland of Poyang Lake, China. The Q10 value, calculated using a temperature gradient (10, 15, 20, 25, and 30 °C), was adopted to represent the temperature sensitivities. The average Q10 values of AG, BG, CBH, XYL, NAG, LAP, and PHOS in the lakeshore wetland were 2.75 ± 0.76, 2.91 ± 0.69, 3.34 ± 0.75, 3.01 ± 0.69, 3.02 ± 1.11, 2.21 ± 0.39, and 3.33 ± 0.72, respectively. The Q10 values of all the seven soil extracellular enzymes significantly and positively correlated with flooding duration. The Q10 values of NAG, AG and BG were more sensitive to the changes in flooding duration than the other enzymes. The Q10 values of the carbon, nitrogen, and phosphorus-related enzymes were mainly determined by flooding duration, pH, clay, and substrate quality. Flooding duration was the most dominant driver for the Q10 of BG, XYL, NAG, LAP, and PHOS. In contrast, the Q10 values of AG and CBH were primarily affected by pH and clay content, respectively. This study indicated that flooding regime was a key factor in regulating soil biogeochemical processes of wetland ecosystems under global warming.
... One of the author's explanations was that soil hydrolases mainly degrade unstable reaction substrates, and soil warming leads to the decrease of substrate availability, which will gradually inhibit soil enzyme activities [36]. Although warming can directly increase enzyme activity by increasing enzyme kinetics [37], the effects of these two directions cancel each other, resulting in an insignificant response to warming. ...
In order to explore the influence of climate warming on soil microbial metabolism in the ecosystem and reveal the relationship between soil microbial metabolism limitation and environmental factors, in this study, the effects of warming on soil enzyme activities and nutrient availability were investigated by setting underground heating cables at 2 °C and 4 °C soil warming in a typical Quercus acutissima forest in the northern subtropics, and enzyme stoichiometric models were used to evaluate the limits of soil microbial metabolism. The results showed that soil warming significantly increased the activities of β-1,4-glucosidase (BG) and L-leucine aminopeptidase (LAP), and significantly increased the contents of nitrate nitrogen (NO3−-N) and available phosphorus (AP) in soil. The soil warming increased soil microbial C limitation and alleviated soil microbial P limitation. Our study showed that the change of soil microbial C and P limitation caused by warming may cause a large amount of SOM decomposition in a short period, leading to a large fluctuation of soil carbon turnover, which is not conducive to the stability of the soil C pool. This study provides important insights linking microbial metabolism to soil warming and improves our understanding of C cycling in forest systems.
... At the same time, we also found that sediment was more affected by climate change than water column in the metabolic functions of bacteria related to the carbon and nitrogen cycles. The high concentration of substrate and nutrients in sediment constrains the enzyme's response to temperature [100]. Heat waves can stimulate an increase in bacterial abundance, and this change is more pronounced in sediment, a nutrient-rich substrate [14]. ...
Extreme climatic events, such as heat wave and large temperature fluctuations, are predicted to increase in frequency and intensity during the next hundred years, which may rapidly alter the composition and function of lake bacterial communities. Here, we conducted a year-long experiment to explore the effect of warming on bacterial metabolic function of lake water and sediment. Predictions of the metabolic capabilities of these communities were performed with FAPROTAX using 16S rRNA sequencing data. The results indicated that the increase in temperature changed the structure of bacterial metabolic functional groups in water and sediment. During periods of low temperature, the carbon degradation pathway decreased, and the synthesis pathway increased, under the stimulation of warming, especially under the conditions temperature fluctuation. We also observed that nitrogen fixation ability was especially important in the warming treatments during the summer season. However, an elevated temperature significantly led to reduced nitrogen fixation abilities in winter. Compared with the water column, the most predominant functional groups of nitrogen cycle in sediment were nitrite oxidation and nitrification. Variable warming significantly promoted nitrite oxidation and nitrification function in winter, and constant warming was significantly inhibited in spring, with control in sediments. Co-occurrence network results showed that warming, especially variable warming, made microbial co-occurrence networks larger, more connected and less modular, and eventually functional groups in the water column and sediment cooperated to resist warming. We concluded that warming changed bacterial functional potentials important to the biogeochemical cycling in the experimental mesocosms in winter and spring with low temperature. The effect of different bacteria metabolism functions in water column and sediment may change the carbon and nitrogen fluxes in aquatic ecosystems. In conclusion, the coupling response between different bacterial metabolic functions in water and sediment may improve the ability to mitigate climate change.
... Our results confirmed the general expectation that activity of BG, LAP and AP is stimulated by increasing temperatures up to optimal temperatures above those typically observed in moderate environments, with Q 10 -values for V max and activation energies within the ranges typically observed for soil exoenzymes (Trasar-Cepeda et al., 2007;Brzostek and Finzi, 2012;German et al., 2012;Stone et al., 2012;Steinweg et al., 2013;Razavi et al., 2015Razavi et al., , 2016Nottingham et al., 2016). However, despite few suggestive trends, temperature sensitivity did not vary significantly with depth for any enzyme or kinetic property, based on either Q 10 , following a linear Arrhenius model, or T opt , TS max and C p ‡ of V max estimated by the non-linear MMRT model. ...
... The uniform temperature sensitivity observed here contradicted our initial hypothesis that exoenzymes in deeper soils are more sensitive to temperature changes as a result of microbial adaptation to lower and narrower temperature ranges (Schipper et al., 2014), as observed at our site. Previous studies have observed that exoenzymes from colder soil environments tend to be more sensitive to temperature (Koch et al., 2007;Brzostek and Finzi, 2012), as well as in some subsoils in relation to surface soils (Steinweg et al., 2013). Therefore, we expected that Q 10 -values and activation energies would increase with depth, whereas either T opt , C p ‡ , or both, would decrease. ...
Current knowledge of the mechanisms driving soil organic matter (SOM) turnover and responses to warming is mainly limited to surface soils, although over 50% of global soil carbon is contained in subsoils. Deep soils have different physicochemical properties, nutrient inputs, and microbiomes, which may harbor distinct functional traits and lead to different SOM dynamics and temperature responses. We hypothesized that kinetic and thermal properties of soil exoenzymes, which mediate SOM depolymerization, vary with soil depth, reflecting microbial adaptation to distinct substrate and temperature regimes. We determined the Michaelis-Menten (MM) kinetics of three ubiquitous enzymes involved in carbon (C), nitrogen (N) and phosphorus (P) acquisition at six soil depths down to 90 cm at a temperate forest, and their temperature sensitivity based on Arrhenius/Q 10 and Macromolecular Rate Theory (MMRT) models over six temperatures between 4-50 • C. Maximal enzyme velocity (V max) decreased strongly with depth for all enzymes, both on a dry soil mass and a microbial biomass C basis, whereas their affinities increased, indicating adaptation to lower substrate availability. Surprisingly, microbial biomass-specific catalytic efficiencies also decreased with depth, except for the P-acquiring enzyme, indicating distinct nutrient demands at depth relative to microbial abundance. These results suggested that deep soil microbiomes encode enzymes with intrinsically lower turnover and/or produce less enzymes per cell, reflecting distinct life strategies. The relative kinetics between different enzymes also varied with depth, suggesting an increase in relative P demand with depth, or that phosphatases may be involved in C acquisition. V max and catalytic efficiency increased consistently with temperature for all enzymes, leading to overall higher SOM-decomposition potential, but enzyme temperature sensitivity was similar at all depths and between enzymes, based on both Arrhenius/Q 10 and MMRT models. In a few cases, however, temperature affected differently the kinetic properties of distinct Frontiers in Microbiology | www.frontiersin.org 1 November 2021 | Volume 12 | Article 735282 Alves et al. Exoenzyme Kinetics and Temperature Sensitivity enzymes at discrete depths, suggesting that it may alter the relative depolymerization of different compounds. We show that soil exoenzyme kinetics may reflect intrinsic traits of microbiomes adapted to distinct soil depths, although their temperature sensitivity is remarkably uniform. These results improve our understanding of critical mechanisms underlying SOM dynamics and responses to changing temperatures through the soil profile.
... Bonmati et al., 1991;Geisseler et al., 2010). Several studies have also reported seasonal effects on enzyme activities due to temperature and precipitation changes which were not possible to investigate in this study (Brzostek and Finzi, 2012;Wallenstein et al., 2009). Data for the parameters such as soil organic carbon and clay content are often not reported together with protease activity. ...
Proteases play a crucial role in the soil nitrogen (N) cycle by converting protein to oligopeptides and amino acids. They are often viewed as a bottleneck in terrestrial N cycling; therefore, it is vital that we have robust methods for evaluating protease activity in soil and to understand global patterns of protease activity. In response to this, several laboratory-based protease methods have been developed and subsequently modified. However, the validity of these different approaches remains largely unknown. In addition, the lack of standardised protocols makes it difficult to compare protease activity across studies. In this systematic synthesis, we critically evaluate the most common colorimetric and fluorimetric methods used to measure soil protease activity involving 680 independent studies and 1,491 individual assays. To investigate the key regulators of soil protease activity, we collected associated metadata on environmental (mean annual temperature and soil pH) and methodological (assay temperature and pH) factors. Protease activity measured with colorimetric substrates were centred around ca. 1000 nmol product g⁻¹ h⁻¹, whilst rates measured with fluorimetric substrates were lower at ca. 100 nmol product g⁻¹ h⁻¹. Fluorimetric and colorimetric substrates target different proteases which are likely to have different abundances, kinetic parameters, catalytic mechanism or ecological function suggesting why colorimetric substrates have a higher protease activity. We found soil protease activity varied widely around these peaks, likely due to a wide range of environmental or methodological factors that may influence/bias the result. We present the following recommendations for measuring soil protease activity: 1) report assay conditions and soil characteristics, particularly pH and temperature, 2) conduct the assay at either field or optimised pH and temperature conditions, and, 3) check that measurements lie between 0-5000 nmol product g⁻¹ h⁻¹. This will help reduce the variation in soil protease activity measurements due to methodological bias and improve reporting of abiotic and biotic associated data. Altogether this will lead to a better understanding of the ecological drivers of protease activity and refine parameterisation of global biogeochemical models.
... Previous studies have shown that increased soil temperature can increase soil enzyme activity 92 www.nature.com/scientificreports/ some differences in the temperature sensitivity for different ecosystems and different kinds of soil enzymes 96,97 . Soil carbon turnover and nutrient cycling depend on soil enzyme activity 98 . ...
Vegetation degradation, due to climate change and human activities, changes the biomass, vegetation species composition, and soil nutrient input sources and thus affects soil nutrient cycling and enzyme activities. However, few studies have focused on the responses of soil nutrients and enzymes to vegetation degradation in high-altitude wet meadows. In this study, we examined the effects of vegetation degradation on soil nutrients (soil organic carbon, SOC; total nitrogen, TN; total phosphorus, TP) and enzyme activities (i.e., urease, catalase, amylase) in an alpine meadow in the eastern margin of the Qinghai-Tibet Plateau. Four different levels of degradation were defined in terms of vegetation density and composition: primary wet meadow (CK), lightly degraded (LD), moderately degraded (MD), and heavily degraded (HD). Soil samples were collected at depth intervals of 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm to determine soil nutrient levels and enzyme activities. The results showed that SOC, TN, catalase and amylase significantly decreased with degradation level, while TP and urease increased with degradation level (P < 0.05). Soil nutrient and enzyme activity significantly decreased with soil depth (P < 0.05), and the soil nutrient and enzyme activity exhibited obvious "surface aggregation". The activities of soil urease and catalase were strongest in spring and weakest in winter. The content of TN in spring, summer, and autumn was significantly higher than observed in winter (P < 0.05). The soil TP content increased in winter. Soil amylase activity was significantly higher in summerm than in spring, autumn, and winter (P < 0.05). TP was the main limiting factor for plant growth in the Gahai wet meadow. Values of SOC and TN were positively and significantly correlated with amylase and catalase (P < 0.05), but negatively correlated with urease (P < 0.05). These results suggest the significant role that vegetation degradation and seasonal freeze–thaw cycle play in regulating enzyme activities and nutrient availability in wet meadow soil.
... The C/N ratio also determines the rate of organic matter transformation and its direction [44,45]. A high soil content of organic matter (its layer and the degree of decomposition) determine the temperature and moisture content of topsoil layers, which in turn has a significant effect on the level of activity of enzymes, especially dehydrogenases [5,10,46,47]. The pH value also has a significant impact on soil microbial activity and enzymes exhibit high sensitivity to soil pH [48], which is also evidenced by the results of this study. ...
This study was conducted over the period 2017-2019 in Czesławice (central Lublin region, Poland). The aim of the present study was to compare chemical soil quality parameters (soil pH, available P and K, organic carbon, and total nitrogen content) and soil enzymatic activity (dehydrogenase, acid phosphatase, alkaline phosphatase, urease, protease) in organic and conventional farming systems. The experimental design included two crop rotations (organic and conventional) in which identical plant species were grown: sugar beet-spring barley-red clover-winter wheat-oats. The loess soil on which the experiment was conducted was characterized by the grain size distribution of silt loam, and this soil was categorized as good wheat soil complex (soil class II). The experiment was set up as a split-plot design in triplicate in plots with an area of 40 m 2. Soil sampling was carried out using a soil auger within an area of 0.20 m 2 (from the 0 to 20 cm layer) in each plot during the autumn period. Over the 3-year study period, it was found that the organic system contributed to an increased soil content of organic carbon and total nitrogen. Moreover, a significantly higher soil pH value and a favorable narrow C/N ratio were found under the organic system (regardless of the crop species). Under the conventional system, in turn, a higher soil phosphorus and potassium content was observed. Enzymatic tests of the soil in the five-field crop rotation proved significantly higher activity of all the enzymes studied (in particular that of dehydrogenase, protease, and urease) in the organic system relative to the conventional one, regardless of the crop plant. Among the plants grown in crop rotation, sugar beet, and red clover had the most beneficial effect on the activity of the soil enzymes, followed by oats (especially under the organic system). The activity of the studied enzymes in the organic system was positively correlated (statistically significantly) with favorable soil pH, a higher content of organic C, and total N, and C/N ratio.
