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1.
The soil microbial biomass and activity were estimated for seven field (intensive and extensive management), grassland (dry and wet), and forest (beech, dry and wet alder) sites. Three of the sites (wet grassland, dry and wet alder) are located on a lakeshore and are influenced by lake water and groundwater. Four different methods were selected to measure and characterize the microbial biomass. Values of microbial biomass (weight basis) and total microbial biomass per upper horizon and hectare (volume basis) were compared for each site.Fumigation-extraction and substrate-induced respiration results were correlated but dit not give the same absolute values for microbial biomass content. When using the original conversion factors, substrate-induced respiration gave higher values in field and dry grassland soils, and fumigation-extraction higher values in soils with low pH and high water levels (high organic content). Results from dimethylsulfoxide reduction and arginine ammonification, two methods for estimating microbial activity, were not correlated with microbial biomass values determined by fumigation-extraction or substrate-induced respiration in all soils examined. In alder forest soils dimethylsulfoxide reduction and arginine ammonification gave higher values on the wet site than on the dry site, contrary to the values estimated by fumigation-extraction and substrate-induced respiration. These microbial activities were correlated with microbial biomass values only in field and dry grassland soils. Based on soil dry weight, microbial biomass values increased in the order intensive field, beech forest, extensive field, dry grassland, alder forest, wet grassland. However, microbial biomass values per upper horizon and hectare (related to soil volume) increased in agricultural soils in the order intensive field, dry grassland, extensive field, wet grassland and in forest soils in the order beech, wet alder, dry alder. We conclude that use of the original conversion factors with the soils in the present study for fumigation-extraction and substrate-induced respiration measurements does not give the same values for the microbial biomass. Furthermore, dimethylsulfoxide reduction and arginine ammonification principally characterize specific microbial activities and can be correlated with microbial biomass values under specific soil conditions. Further improvements in microbial biomass estimates, particularly in waterlogged soils, may be obtained by direct counts of organisms, ATP estimate, and the use of 14C-labelled organic substrates. From the ecological viewpoint, data should also be expressed per horizon and hectare (related to soil volume) to assist in the comparison of different sites.  相似文献   

2.
The aim of this study was to determine the effects of plant absence or presence on microbial properties and enzyme activities at different levels of salinity in a sandy clay soil. The treatments involved five salinity levels—0.5 (control), 2.5, 5, 7.5, and 10 dS m?1 which were prepared using a mixture of chloride salts—and three soil environments (unplanted soil, and soils planted with either wheat or clover) under greenhouse conditions. Each treatment was replicated three times. At the end of the experiment, soil microbial respiration, substrate-induced respiration (SIR), microbial biomass C (MBC), and enzyme activities were determined after plant harvest. Increasing salinity decreased soil microbial properties and enzyme activities, but increased the metabolic quotient (qCO2) in both unplanted and planted soils. Most microbial properties of planted soils were greater than those of unplanted soils at low to moderate salinity levels, depending upon plant species. There was a small or no difference in soil properties between the unplanted and planted treatments at the highest salinity level, indicating that the indirect effects of plant presence might be less important due to significant reduction of plant growth. The lowered microbial activity and biomass, and enzyme activities were due to the reduction of root activity and biomass in salinized soils. The lower values of qCO2 in planted than unplanted soils support the positive influence of plant root and its exudates on soil microbial activity and biomass in saline soils. Nonetheless, the role of plants in alleviating salinity influence on soil microbial activities decreases at high salinity levels and depends on plant type. In conclusion, cultivation and growing plant in abandoned saline environments with moderate salinity would improve soil microbial properties and functions by reducing salinity effect, in particular planting moderately tolerant crops. This helps to maintain or increase the fertility and quality of abandoned saline soils in arid regions.  相似文献   

3.
Temperature, drying, and rewetting are important climatic factors that control microbial properties. In the present study we looked at the respiration rates, adenosine 5′‐triphosphate (ATP) content, and adenylate energy charge (AEC) as a measure for energy status of microbial biomass in the upper 5 cm of mineral soils of three beech forests at different temperatures and after rewetting. The soils differed widely in pH (4.0 to 6.0), microbial biomass C (92 to 916 μg (g DW)—1) and ATP content (2.17 to 7.29 nmol ATP (g DW)—1). The soils were incubated for three weeks at 7 °C, 14 °C, and 21 °C. After three weeks the microbial properties were determined, retaining temperature conditions. The temperature treatment did not significantly affect AEC or ATP content, but respiration rates increased significantly with increasing temperature. In a second experiment the soils were dried for 12 hours at 40 °C. Afterwards the soils were rewetted and microbial properties were monitored for 72 hours. After the drying, respiration rates dropped below the detection limit, but within one hour after rewetting respiration rates increased above control level. Drying reduced AEC by 16 % to 44 % and ATP content by 47 % to 78 %, respectively. Rewetting increased AEC and ATP content significantly as compared to dry soil, but after 72 hours the level of the controls was still not reached. The level of AEC values indicated dormant cells, but ATP content increased. These results indicate that the microbial carbon turnover was not directly linked to microbial growth or microbial energy status. Furthermore our results indicate that AEC may describe an average energy status but does not reflect phases of growing, dormant, or dying cells in the complex microbial populations of soils.  相似文献   

4.
Attempts to determine available carbon in soils   总被引：10，自引：0，他引：10  
Summary The size of the C pool that is readily available to microorganisms affects important N transformations that occur in soils, e.g., denitrification and N immobilization. In the present work, the C content of soil extracts, the C in water displaced from soil and biomass C were compared as indicators of available C. A comparison of C measured by the anthrone method and a total organic-C analysis of extracts indicated that only a small portion of C was in carbohydrates. The substrate-induced respiration method of measuring biomass in conjunction with the Wright-Hobbie model was used as an additional determination of available C. Total organic-C analysis of a 1 N H2SO4 extract gave the highest C values (500–1700 mg C kg-1 soil) and the substrate-induced respiration method gave the lowest (1–5 mg glucose equivalents kg-1 soil). The C values closest to the C turnover measured in long-term incubation studies were obtained by the substrate-induced respiration method using the Wright-Hobbie model.Contribution from the Soil-Microbial Systems Laboratory, NRI, USDA-ARS, Beltsville, MD 20705, USA  相似文献   

5.
The effect of liming on microbial biomass C and respiration activity was studied in four liming experiments on young pine plantations. One of the experimental sites had been limed and planted 12 years before, two 5 years before, and one a year before soil sampling. The youngest experimental site was also treated with ash fertilizer. Liming raised the pHKCl of the humus layer by 1.5 units or less. Microbial biomass was measured using the fumigation-extraction and substrate-induced respiration methods. Liming did not significantly affect microbial biomass C, except in the experiment which had been limed 11 years ago, where there was a slight biomass increase. Basal respiration, which was measured by the evolution of CO2, increased in the limed soils, except for the youngest experiment, where there was no effect. Ash fertilization raised the soil pHKCl by about 0.5 unit, but did not influence microbial biomass C or basal respiration. Fumigation-extraction and substrate-induced respiration derived microbial biomass C values were correlated positively with each other (r=0.65), but substrate-induced respiration gave approximately 1.3 times higher results. In addition, the effect of storing the soil samples at +6 and -18°C was evaluated. The effects were variable but, generally, the substrate-induced respiration derived microbial biomass C decreased, and the fumigation-extraction derived microbial biomass C and basal respiration decreased or were not affected by storage.  相似文献   

6.
Bacterial and fungal contributions to microbial respiration in three beechwood soils rich in C (two basalt soils and one limestone soil) were investigated by using streptomycin and cycloheximide to inhibit substrate-induced respiration after glucose (8000 g g-1), N, and P addition to soil samples. The inhibitors were added as solutions (2000, 8000, and 16000 g g-1) and the reduction in substrate-induced respiration after separate and combined inhibitor addition was measured in an automated electrolytic microrespirometer. Bacterial and fungal contributions to microbial respiration were calculated using the interval 6–10 h after inhibitor application. The microbial biomas was smaller in the two basalt soils (Oberhang and Mittelhang) than in the limestone soil (Unterhang). In the presence of both inhibitors, microbial respiration was inhibited by a maximum of 45, 45, and 25% in the two basalt soils and the limestone soil, respectively. Inhibition of microbial respiration was at a maximum at streptomycin and cycloheximide concentrations of 16000 g g-1. The inhibitor additivity ratio approached 1.0 even at high inhibitor concentrations, indicating high inhibitor selectivity. Calculated prokaryote: eukaryote ratios indicated lower bacterial contributions to the microbial biomass in the Mettelhang (0.74) and Unterhang (0.73) than in the Oberhang (0.88) soil.  相似文献   

7.
Methods for measuring soil microbial biomass C were reviewed. The basic ideas behind the fumigation-incubation method, the fumigation-extraction method, the substrate-induced respiration method, and the ATP method were examined together with the advantages, disadvantages, and limitations as reported in the literature and those found by our own recent investigations.The fumigation-incubation method is the basic technique which is also used for calibration of the three other methods. It is characterized by simple performance without the need of expensive equipment. Its application is limited to soils with a pH above 5 and to soils that do not contain easily degradable C sources. If these limitations are not considered, too low or even negative biomass values will be obtained. These restrictions are largely overcome by the fumigation-extraction method. However, the k EC factor applied to calculate microbial biomass C from the C additionally made extractable by the fumigation is still controversial. The substrate-induced respiration requires expensive equipment for the hourly measurement of soil respiration. This method is also susceptible to amendment of soils with C sources, leading to an overestimate of biomass C. Although a few authors disagree with some basic assumptions behind the methods described, they are widely used and accepted. The use of ATP to measure biomass C in soil is far more uncertain. A high diversity of applied techniques for the extraction and measurement of ATP has led to biomass C : ATP ratios which vary between about 150 and 1 000. Our own current investigations are expected to shed more light on the problems of ATP extraction. Preliminary results indicate that a constant biomass C : ATP ratio of about 200 may be more realistic.  相似文献   

8.
A short-term mesocosm experiment was conducted to ascertain the impact of tebuconazole on soil microbial communities. Tebuconazole was applied to soil samples with no previous pesticide history at three rates: 5, 50 and 500 mg kg−1 DW soil. Soil sampling was carried out after 0, 7, 30, 60 and 90 days of incubation to determine tebuconazole concentration and microbial properties with potential as bioindicators of soil health [i.e., basal respiration, substrate-induced respiration, microbial biomass C, enzyme activities (urease, arylsulfatase, β-glucosidase, alkaline phosphatase, dehydrogenase), nitrification rate, and functional community profiling]. Tebuconazole degradation was accurately described by a bi-exponential model (degradation half-lives varied from 9 to 263 days depending on the concentration tested). Basal respiration, substrate-induced respiration, microbial biomass C and enzyme activities were inhibited by tebuconazole. Nitrification rate was also inhibited but only during the first 30 days. Different functional community profiles were observed depending on the tebuconazole concentration used. It was concluded that tebuconazole application decreases soil microbial biomass and activity.  相似文献   

9.
The phenolic acids p-hydroxybenzoic, ferulic, caffeic and vanillic acid, were added to soil of the Countesswells series that had been fallow or carried crops of potatoes, peas or barley for two consecutive years. Changes in phenolic acid concentration, the soil biomass, the respiration rate, and soil amylase activity were measured over 28 days. All the phenolic acids were sorbed by the soils which was generally in the order caffeic > ferulic = vanillic > hydroxybenzoic acid. The phenolic acids stimulated soil respiration and increased the biomass as determined by the substrate-induced respiration method. but the fumigation method of biomass assessment gave anomalous results. The soil amylase activity was initially increased by phenolic acid amendments but soon decreased, and after 7 days was less than in non-amended soil although activity had increased again after 28 days. The rates of respiration and the total phenolic acid concentrations were similar to unamended controls after 28 days. The immediate respiration response, measured 1–6 h after amendment, indicated that caffeic acid gave the largest initial response of the phenolic tested, this being 55–72% of that given by glucose. Soil from the potato plot showed the highest immediate response to the phenolic acid amendments measured as a proportion of the respiration response to glucose. The findings suggest that some crops stimulate the growth of phenolic-acid degrading organisms.  相似文献   

10.
The need to identify microbial community parameters that predict microbial activity is becoming more urgent, due to the desire to manage microbial communities for ecosystem services as well as the desire to incorporate microbial community parameters within ecosystem models. In dryland agroecosystems, microbial biomass C (MBC) can be increased by adopting alternative management strategies that increase crop residue retention, nutrient reserves, improve soil structure and result in greater water retention. Changes in MBC could subsequently affect microbial activities related to decomposition, C stabilization and sequestration. We hypothesized that MBC and potential microbial activities that broadly relate to decomposition (basal and substrate-induced respiration, N mineralization, and β-glucosidase and arylsulfatase enzyme activities) would be similarly affected by no-till, dryland winter wheat rotations distributed along a potential evapotranspiration (PET) gradient in eastern Colorado. Microbial biomass was smaller in March 2004 than in November 2003 (417 vs. 231 μg g−1 soil), and consistently smaller in soils from the high PET soil (191 μg g−1) than in the medium and low PET soils (379 and 398 μg g−1, respectively). Among treatments, MBC was largest under perennial grass (398 μg g−1). Potential microbial activities did not consistently follow the same trends as MBC, and the only activities significantly correlated with MBC were β-glucosidase (r = 0.61) and substrate-induced respiration (r = 0.27). In contrast to MBC, specific microbial activities (expressed on a per MBC basis) were greatest in the high PET soils. Specific but not total activities were correlated with microbial community structure, which was determined in a previous study. High specific activity in low biomass, high PET soils may be due to higher microbial maintenance requirements, as well as to the unique microbial community structure (lower bacterial-to-fungal fatty acid ratio and lower 17:0 cy-to-16:1ω7c stress ratio) associated with these soils. In conclusion, microbial biomass should not be utilized as the sole predictor of microbial activity when comparing soils with different community structures and levels of physiological stress, due to the influence of these factors on specific activity.  相似文献   

11.
Summary We studied the effects of amending soils with different volumes of water or glucose solution on respiration rates measured as CO2 evolution. Basal respiration was not significantly affected by the volume of water amendment, but substrate-induced respiration in static soil solutions was significantly reduced by increasing water contents. Inhibition of substrate-induced respiration was removed by continuously agitating the incubation vessels. Estimates of substrate-induced respiration rates for six soils differed markedly, depending on whether the vessels were stationary or agitated during the incubation. Agitation allowed increased discrimination between substrate-induced respiration rates for the soils, while static incubation only differentiated the soil with the highest substrate-induced respiration rate from the other soils.  相似文献   

12.
Microbial biomass C, ATP, and substrate-induced respiration were measured in the organic layers and the mineral A horizon of three beech forest soils with moder humus differing in Ca and Mg supply. Analyses of variance showed that horizon-specific differences explained most of the variance in the three microbial parameters. All three were significantly interrelated, with Spearman rank correlation coefficients of between 0.86 and 0.93. However, differences in the decline of these parameters with depth led to horizon-specific differences in their ratios. Thus, the ratios were not markedly interrelated. The mean ATP: microbial C ratio was 5.2 mol ATP g-1 C in the L 2 layer, 19.5 in the F layers, and 9.6 in the H and A horizons. The ratio of substrate-induced respiration to microbial C varied between 39.3 and 82.2 O2h-1 g-1 C in the F1 layers and between 5.3 and 32.1 l in the other layers. It is concluded that the use of different parameters can help to analyze both horizonand site-specific differences in microbial performance.  相似文献   

13.
Microbial properties and nematode abundance were measured along a gradient of increasing Cu, Cr, and As concentrations (50–1300 mg Cr kg-1) in the top 5 cm of a pasture soil contaminated by runoff of preserving liquor from an adjacent timber-treatment plant. Microbial biomass C and N were significantly (P<0.05) lower in contaminated than uncontaminated soils. The amount of microbial biomass C as a percentage of total organic C declined significantly (r 2 value with Cr 0.726*) with increasing contamination, and the ratio of respired C to biomass C was significantly (P<0.05) higher with contamination. Substrate-induced respiration, microbial biomass P, and denitrification declined (r2 value with Cr 0.601, 0.833*, and 0.709*, respectively) with increasing contamination. Increasing contamination had no effect on prokaryote substrate-induced respiration but eukaryote: eukaryote substrate-induced respiration declined significantly (r 2 value with Cr 0.722*). Accordingly, the ratio of prokaryote substrate-induced respiration increased significantly (r 2 value with Cr 0.799*) with contamination. There was a significant (r 2 value with Cr 0.872*) hyperbolic relationship between sulphatase activity and contamination, with activity declining by approximately 80% at >1000 mg Cr kg-1. Increasing contamination had no effect on basal respiration, dimethyl sulphoxide reduction, and phosphatase, urease, and invertase activities. Numbers of plant-associated nematodes declined significantly (r 2 value with Cr 0.780*) with contamination. On a percentage basis, plant-feeding nematodes predominated in less contaminated soils, whereas bacterial-feeding and predatory nematodes predominated in heavily contaminated soils. The use of the fumigation—incubation procedure for measurement of microbial biomass C in heavy-metal contaminated soils is discussed.  相似文献   

14.
Amending soils with glucose (5 mg g?1) resulted in an immediate increase in microbial activity and within 30 min the rates of heat output and respiration at 22° C were increased by up to 17.8 and 23.4 times, respectively. The increased rate of heat output remained stable for up to 6 h and there was good correlation with the amount of CO2 respired. The soil biomass was calculated by the method of Anderson and Domsch (1978). The rate of heat output of the biomass varied in different soils and ranged from 11.5 to 83.7 Jh?1 g?1 biomass C. In glucose-amended soils, however, the rate of heat output was much more consistent; the soils were in two groups having between 169–265 Jh?1g?1 biomass C or 454–482 J h?1 g?1 biomass C, both the latter two soils were from pasture. The increased rate of heat output from the amended soils was lower than expected from the respiration rate and the heat of oxidation of glucose, suggesting that a proportion of the CO2 respired was from catabolism of substrates other than glucose. Use of 14C-glucose confirmed that between 57–91% of the CO2 was derived from the glucose substrate.  相似文献   

15.
The increase in microbial C content, cumulative respiration and changes in ”︁available” C were determined after adding glucose (2 mg glucose-C (g soil)—1, ”︁C”), glucose + nitrogen (”︁C+N”) or glucose + nitrogen + phosphorus (”︁C+N+P”) to four soils. In two sandy soils, one agricultural and the other from a beech forest in Germany, available C was still present approximately 7 days after C addition. The supplement N and N+P decreased the content of available C and stimulated respiration rate and microbial growth. In two loamy forest soils from Italy, which had a high native content of microbial C, available C was present in the beech soil but not in a silver fir soil treated with C+N. In the Italian beech and fir soil, microbial growth was highest with C+N+P and C+N addition respectively. Available C remaining in the soil was related to some extent to the native microbial C content. However, microbial growth and respiration response varied between soil and treatment. The respiratory coefficient, that is the ratio of assimilated to respired C, varied between 0.0 and 1.45 μg Cmic (μg CO2-C)—1 and was generally higher when a large amount of native biomass was present. The eco-physiological strategy of the soil microbiota in using C seemed to shift according to the biomass content, the added concentration and composition of available substrates, and emergent system properties.  相似文献   

16.
Brazilian industry produces huge amounts of tannery sludge as residues, which is often disposed by landfilling or land application. However, consecutive amendment of such composted industrial wastes may cause shifts in soil microbial biomass （SMB） and enzyme activity. This study aimed to evaluate SMB and enzyme activity after 3-year consecutive composted tannery sludge （CTS） amendment in tropical sandy soils. Different amounts of CTS （0.0, 2.5, 5.0, 10.0, and 20.0 t ha-1） were applied to a sandy soil. The C and N contents of SMB, basal and substrate-induced respiration, respiratory quotient （qCO2）, and enzyme activities were determined in the soil samples collected after CTS amendment for 60 d at the third year. After 3 years, significant changes were found in soil microbial properties in response to different CTS amounts applied. The organic matter and Cr contents significantly increased with increasing CTS amounts. SMB and soil respiration peaked following amendment with 10.0 and 20.0 t ha-1 of CTS, respectively, while qCO2 was not significantly affected by CTS amendment. However, soil enzyme activity decreased significantly with increasing CTS amounts. Consecutive CTS amendment for 3 years showed inconsistent and contrasting effects on SMB and enzyme activities. The decrease in soil enzyme activities was proportional to a substantial increase in soil Cr concentration, with the latter exceeding the permitted concentrations by more than twofold. Thus, our results suggest that a maximum CTS quantity of 5.0 t ha-1 can be applied annually to tropical sandy soil, without causing potential risks to SMB and enzyme activity.  相似文献   

17.
The characteristics of the respiration activity of leached chernozems under different land uses were studied. The use of soil-conservation technologies of crop cultivation led to an increase in the basal and substrate-induced respiration and in the content of the carbon of the microbial biomass. With respect to the microbial activity and the sustainability of the microbial pool, the soils were arranged into the following order: virgin soils → soils treated with soil-conservation technologies → soils treated with traditional methods.  相似文献   

18.
Heavy metal availability, microbial biomass and respiration, bacterial diversity and enzyme activity were studied in soils from long-term field experiments contaminated with Mn-Zn- or Cd-Ni-rich sludge, incorporated into soils at two different rates. Soils that never received sludge were used as controls. Microbial biomass C content (BC) and soil respiration (CO2-C) were slightly reduced in soils amended with Mn-Zn at the higher incorporation rate whereas in soils receiving Cd-Ni-rich sludge BC and respiration were unaffected. Metabolic quotient values (qCO2) calculated by the BC-to-CO2-C ratio were not significantly different, regardless of the sludge type whereas the microbial biomass C-to-total organic C (BC-to-TOC) ratios were significantly reduced in the soils receiving the higher rates of both sludge types. Phosphomonoesterase, β-glucosidase and arylsulfatase activities and hydrolase-to-BC ratios, were significantly reduced in soils amended with Ni-Cd-sludge at both rates, whereas the Mn-Zn-sludge only reduced the arylsulfatase activity at the higher rate. Protease activity was generally higher in all the sludge-amended soils as compared to control soils whereas urease activity was unaffected by sludge amendments. The structure of the bacterial community, as determined by denaturing gradient gel electrophoresis (DGGE), was different in the sludge-amended soils as compared to the respective controls. The most important changes were observed in the soils amended with high-level Ni-Cd sludge. Because some of the adverse effects were observed at moderate contamination levels, our results indicate that the presence of certain heavy metal combinations can be a serious limitation for sludge disposal.  相似文献   

19.
 A model describing the respiration curves of glucose-amended soils was applied to the characterization of microbial biomass. Both lag and exponential growth phases were simulated. Fitted parameters were used for the determination of the growing and sustaining fractions of the microbial biomass as well as its specific growth rate (μ max). These microbial biomass characteristics were measured periodically in a loamy silt and a sandy loam soil incubated under laboratory conditions. Less than 1% of the biomass oxidizing glucose was able to grow immediately due to the chronic starvation of the microbial populations in situ. Glucose applied at a rate of 0.5 mg C g–1 increased that portion to 4–10%. Both soils showed similar dynamics with a peak in the growing biomass at day 3 after initial glucose amendment, while the total (sustaining plus growing) biomass was maximum at day 7. The microorganisms in the loamy silt soil showed a larger growth potential, with the growing biomass increasing 16-fold after glucose application compared to a sevenfold increase in the sandy loam soil. The results gained by the applied kinetic approach were compared to those obtained by the substrate-induced respiration (SIR) technique for soil microbial biomass estimation, and with results from a simple exponential model used to describe the growth response. SIR proved to be only suitable for soils that contain a sustaining microbial biomass and no growing microbial biomass. The exponential model was unsuitable for situations where a growing microbial biomass was associated with a sustaining biomass. The kinetic model tested in this study (Panikov and Sizova 1996) proved to describe all situations in a meaningful, quantitative and statistically reliable way. Received: 19 July 1999  相似文献   

20.
The solfatara field is a unique ecosystem characterized by harsh conditions such as acidic soils. We examined the respiration rate and phospholipid fatty acid (PLFA) content of solfatara soils and their responses to carbon and nitrogen addition to determine whether soil microbial respiration and biomass in a solfatara field are limited by substrate availability. Soil samples were collected from locations along a transect across a solfatara field in Oita Prefecture, Japan. The soil in the central part of the solfatara field was highly acidic (pH 2.4) and contained low amounts of carbon and nitrogen. Low basal respiration rates were detected in these soil samples. Measurements of substrate-induced respiration (SIR) and PLFA contents suggested that it was partly attributable to low microbial biomass. Addition of a carbon source (glucose) to the solfatara soil engendered a marked increase in the microbial respiration rate, whereas the nitrogen source (ammonium nitrate) application had no marked effect. Addition of both carbon and nitrogen caused a nearly eightfold increase in the microbial respiration rate and a threefold increase in the total PLFA contents. These results suggest that some acidophilic and/or acid-tolerant microorganisms exist in solfatara soil, but that their respiration and biomass are limited by low substrate availability.  相似文献   

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