The effect of pollutants (heavy metals and diesel fuel) on the respiratory activity of constructozems (artificial soils)

Young (1 month old) and mature (2 years old) constructozems (artificial soils) were supplemented with individual heavy metal salts or diesel fuel at different concentrations. The polluted and control constructozem variants were incubated and sampled at different time points to determine microbial biomass carbon (Cmic) and microbial respiration (MR). These parameters were found to be almost twice higher in the young than in the mature constructozem, with all pollutants causing an increase in Cmic, MR, and MR/Cmic = qCO2 values. The pollutant type had an effect on MR and qCO2 variances, and the time of exposure, on Cmic. The qCO2 value showed a strong positive correlation with pollutant concentrations, allowing this parameter to be regarded as a suitable indicator of urban environmental pollution

Microbial Indicators of Urban Soils and Their Role in the Assessment of Ecosystem Services: a Review

Abstract: An important element of the urban environment is soil, the balanced functioning of which largely depends on the soil microbiome. The state of the microbiome can be identified by different microbial indicators. However, there is still no answer to the question: which microbial indicators can most informatively reflect the functioning of urban soils and be useful in planning and landscaping urban areas? Databases eLibrar-y.ru, Web of Science, and Scopus were used to collect Russian and foreign papers published in the past 25 years on the study of the soil microbial properties in different cities of the world. It is revealed that the main attention in the study of urban soils is directed to the assessment of the microbial taxonomic structure, its gases’ production and enzymatic activities, the content of microbial biomass, its ecophysiological status, microbial functional diversity, cell morphology, and the presence of pathogenic and opportunistic microorganisms. The criteria of various microbial indicators (reproducibility, selectivity, cost, standardization, interpretation and understanding, recognition by the scientific community) are proposed to illustrate their acceptability and informative value for assessing the functions of urban soils and ecosystem services. The highest correspondence with such criteria was found for the soil microbial activity and the ecophysiological status, and the lowest belongs to the abundance of functional genes and “key groups” of microorganisms. The necessity of studying the relationship of the taxonomic diversity of the microbiome of urban soils with their main functions and the interpretation of experimental results in terms of ecosystem services is justified. © 2021, Pleiades Publishing, Ltd

Atmospheric Nitrogen Deposition and the Properties of Soils in Forests of Vologda Region

Twenty plots (20 m2 each) were selected in coniferous and mixed forests of the industrial Vologda district and the Vytegra district without developed industries in Vologda region. In March, snow cores corresponding to the snow cover depth were taken on these plots. In August, soil samples from the 0- to 20-cm layer of litter-free soddy-podzolic soil (Albic Retisol (Ochric)) were taken on the same plots in August. The content of mineral nitrogen (Nmin), including its ammonium (NH+ 4) and nitrate (NO- 3) forms, was determined in the snow (meltwater) and soil. The contents of total organic carbon, total nitrogen, and elements (Al, Ca); pH; particle size distribution; and microbiological parameters―carbon of microbial biomass (Cmic) and microbial respiration (MR)―were determined in the soil. The ratio MR/Cmic = qCO2 (specific respiration of microbial biomass, or soil microbial metabolic quotient) was calculated. The content of Nmic in meltwater of two districts was 1.7 mg/L on the average (1.5 and 0.3 mg/L for the NH+ 4 and NO– 3 forms, respectively). The annual atmospheric deposition was 0.6–8.9 kg Nmin/ha, the value of which in the Vologda district was higher than in the Vytegra district by 40%. Reliable correlations were found between atmospheric NH+ 4 depositions and Cmic (–0.45), between NH+ 4 and qCO2 (0.56), between atmospheric NO- 3 depositions and the soil NO- 3 (–0.45), and between NO- 3 and qCO2 (–0.58). The content of atmospheric Nmin depositions correlated with the ratios C/N (–0.46) and Al/Ca (–0.52) in the soil. In forests with the high input of atmospheric nitrogen (>2.0 kg NH+ 4/(ha yr) and >6.4 kg Nmin/(ha yr)), a tendency of decreasing Cmic, C/N, and Al/Ca, as well as increasing qCO2, was revealed, which could be indicative of deterioration in the functioning of microbial community and the chemical properties of the soil. © 2018, Pleiades Publishing, Ltd

Soil Microbial Respiration in Subtaiga and Forest-Steppe Ecosystems of European Russia: Field and Laboratory Approaches

Abstract: Our study focuses on testing laboratory measurements of soil microbial respiration as a proxy that in the field conditions. The soil microbial respiration was measured in field (MRfield) and laboratory (MRlab) conditions monthly (from May to October) in subtaiga (mixed forest, meadow) and forest-steppe (broad-leaved forest, virgin steppe) ecosystems of the European Russia. The MRfield was determined through soil respiration partitioning by the conventional substrate-induced respiration method. The MRlab was measured as basal respiration of 10 cm topsoil at 22°C and 60% water holding capacity. The contribution of MRfield to total soil respiration varied during the growing season from 25 to 82% for subtaiga and from 41 to 88% for forest-steppe. The MRfield for studied ecosystems varied from 2.2 to 21.7 g СО2/(m2 d), while MRlab was from 3.5 to 18.6 g СО2/(m2 d). Similar results obtained by field and laboratory approaches were in 50% of measurements in the subtaiga ecosystems and in almost 20% of cases on the forest-steppe. The average MRfield and MRlab for growing season did not significantly differ for all studied ecosystems. These findings demonstrate possible prospects of using laboratory measurement of soil microbial respiration during the growing season to approximate and predict average MRfield for various ecosystems

Эмиссия СО₂, микробная биомасса и базальное дыхание чернозема при различном землепользовании

The relationship between the CO2 emission and microbiological properties was studied in Haplic Chernozem of steppe, forest, bare fallow of the reserve area and in Urbic Technosols of Kursk city. The CO2 emission from the soil surface (EMsurf) and two subsoil layers (at the depths of 10 and 20 cm: EM10, EM20) were monthly measured (May–October) together with simultaneous measurements of the soil temperature and water content. Overall, 360 soil samples were taken from the layers of 0–10, 10–20, and 20–30 cm for determining microbiological properties (microbial biomass carbon, Cmic basal respiration, BR). Soil chemical properties (the contents of organic C, total C, N, P, K, and Ca; and pH) were measured in samples taken in July. The EMsurf of steppe averaged 24 g СО2/(m2 day), which was 1.6, 1.5 and 6 times higher than that of forest, urban, and fallow soils, respectively. In the forest, EM10 and EM20 were two times higher than reference EMsurf they were similar in the fallow and urban soils; and they were 34% lower in the steppe soil. The CO2 emission from the soils of studied ecosystems during the growing season weakly depended on the soil temperature and moisture. The Cmic and BR (0–10 cm) of undisturbed ecosystems (steppe, forest) were higher by, on average, 3–5 and 2–4 times, respectively, that those of the disturbed (fallow, urban) ecosystems. The positive correlations between EMsurf and Cmic, BR (0–10 cm) were found (r = 0.56 and 0.74, respectively). The seasonal average EMsurf for different land uses was mainly (78%) controlled by their BR (linear regression). Therefore, the EMsurf from Chernozems of different land use during the growing season might be predicted on the basis of BR measurements (0–10 cm).В черноземе под степной растительностью, лесом (дубрава), в чистом пару (территория заповедника) и в урбаноземе города Курск (Курская область) изучали взаимосвязь эмиссии СО2 из почвы и ее микробиологических показателей. Измерения эмиссии СО2 с поверхности почвы (ЭМпов) и из двух нижележащих слоев почвы (глубина 10 и 20 см, ЭМ10, ЭМ20) проводили ежемесячно (май–октябрь), одновременно регистрировали температуру и влажность почвы. В отобранных образцах почвы слоев 0–10, 10–20, 20–30 см (всего 360) измеряли микробиологические показатели (углерод микробной биомассы (Смик), базальное дыхание). Химические свойства почвы (содержание Сорг общего С, N, Р, К, Са; рН) определяли в образцах, отобранных в июле. Показано, что ЭМпов степи составила в среднем 24 г СО2/(м2 сут), леса, города и пара – в 1.6, 1.5 и 6 раза меньше соответственно. ЭМ10 и ЭМ20 леса оказалась в среднем в 2 раза больше таковой с поверхности, пара и города – примерно одинаковой, а степи – на 34% меньше. Эмиссия СО2 из почвы изученных экосистем за наблюдаемый период слабо зависела от ее температуры и влажности. Смик и базальное дыхание почвы (0–10 см) ненарушенных экосистем (степи, леса) в среднем в 3–5 и 2–4 раза, соответственно, превышали таковые нарушенных (пара, города). Показана положительная корреляция ЭМпов изученных экосистем с Смик и базальным дыханием (0–10 см, r = 0.56 и 0.74 соответственно). ЭМпов чернозема разного землепользования за вегетационный период на 78% была обусловлена их базальным дыханием (линейная регрессия). Следовательно, ЭМпов чернозема разного землепользования за вегетационный период можно в определенной степени прогнозировать на основе экспериментальных данных о базальном дыхании его верхнего слоя (0–10 см)

Atmospheric Nitrogen Deposition and the Properties of Soils in Forests of Vologda Region

Twenty plots (20 m2 each) were selected in coniferous and mixed forests of the industrial Vologda district and the Vytegra district without developed industries in Vologda region. In March, snow cores corresponding to the snow cover depth were taken on these plots. In August, soil samples from the 0- to 20-cm layer of litter-free soddy-podzolic soil (Albic Retisol (Ochric)) were taken on the same plots in August. The content of mineral nitrogen (Nmin), including its ammonium (NH+ 4) and nitrate (NO- 3) forms, was determined in the snow (meltwater) and soil. The contents of total organic carbon, total nitrogen, and elements (Al, Ca); pH; particle size distribution; and microbiological parameters―carbon of microbial biomass (Cmic) and microbial respiration (MR)―were determined in the soil. The ratio MR/Cmic = qCO2 (specific respiration of microbial biomass, or soil microbial metabolic quotient) was calculated. The content of Nmic in meltwater of two districts was 1.7 mg/L on the average (1.5 and 0.3 mg/L for the NH+ 4 and NO– 3 forms, respectively). The annual atmospheric deposition was 0.6–8.9 kg Nmin/ha, the value of which in the Vologda district was higher than in the Vytegra district by 40%. Reliable correlations were found between atmospheric NH+ 4 depositions and Cmic (–0.45), between NH+ 4 and qCO2 (0.56), between atmospheric NO- 3 depositions and the soil NO- 3 (–0.45), and between NO- 3 and qCO2 (–0.58). The content of atmospheric Nmin depositions correlated with the ratios C/N (–0.46) and Al/Ca (–0.52) in the soil. In forests with the high input of atmospheric nitrogen (>2.0 kg NH+ 4/(ha yr) and >6.4 kg Nmin/(ha yr)), a tendency of decreasing Cmic, C/N, and Al/Ca, as well as increasing qCO2, was revealed, which could be indicative of deterioration in the functioning of microbial community and the chemical properties of the soil. © 2018, Pleiades Publishing, Ltd

Soil CO2 Emission, Microbial Biomass, and Basal Respiration of Chernozems under Different Land Uses

Abstract—: The relationships between the soil CO2 emission and microbial properties have been studied in Haplic Chernozem of steppe, forest (oak), bare fallow of the reserve area and in Urbic Technosols of Kursk city. The CO2 emission was monthly measured (May–October) from the soil surface (EMsurf) and two subsoil layers at the depths of 10 and 20 cm (EM10, EM20), and the soil temperature and water content were simultaneously recorded. Overall, 360 soil samples have been taken from the layers 0–10, 10–20, and 20–30 cm for determining the microbial properties (microbial biomass carbon, Cmic; basal respiration, BR). Soil chemical properties (the organic C content, total C, N, P, K, and Ca; and pH) have been measured in the samples taken in July. The EMsurf of steppe averaged 24 g СО2/(m2 day), which was 1.6, 1.5 and 6 times higher than that of forest, urban, and fallow soils, respectively. In the forest, EM10 and EM20 were two times higher than reference EMsurf; they were similar in the fallow and urban soils; and they were by 34% lower in the steppe soil. The soil CO2 emission of studied ecosystems depended weakly on soil temperature and water content during the growing season. The Cmic and BR (0–10 cm) of undisturbed ecosystems (steppe, forest) were higher by, on average, 3–5 and 2–4 times, respectively, than those of disturbed (fallow, urban) ecosystems. The positive correlations between EMsurf and Cmic, BR (0–10 cm) were found (r = 0.56 and 0.74, respectively). The seasonal average EMsurf for different land uses was controlled mainly (78%) by soil BR (linear regression). Therefore, the EMsurf from Chernozems of different land uses during the growing season might be predicted on the basis of BR measurements (0–10 cm). © 2019, Pleiades Publishing, Ltd

Soil Microbial Respiration in Subtaiga and Forest-Steppe Ecosystems of European Russia: Field and Laboratory Approaches

Abstract: Our study focuses on testing laboratory measurements of soil microbial respiration as a proxy that in the field conditions. The soil microbial respiration was measured in field (MRfield) and laboratory (MRlab) conditions monthly (from May to October) in subtaiga (mixed forest, meadow) and forest-steppe (broad-leaved forest, virgin steppe) ecosystems of the European Russia. The MRfield was determined through soil respiration partitioning by the conventional substrate-induced respiration method. The MRlab was measured as basal respiration of 10 cm topsoil at 22°C and 60% water holding capacity. The contribution of MRfield to total soil respiration varied during the growing season from 25 to 82% for subtaiga and from 41 to 88% for forest-steppe. The MRfield for studied ecosystems varied from 2.2 to 21.7 g СО2/(m2 d), while MRlab was from 3.5 to 18.6 g СО2/(m2 d). Similar results obtained by field and laboratory approaches were in 50% of measurements in the subtaiga ecosystems and in almost 20% of cases on the forest-steppe. The average MRfield and MRlab for growing season did not significantly differ for all studied ecosystems. These findings demonstrate possible prospects of using laboratory measurement of soil microbial respiration during the growing season to approximate and predict average MRfield for various ecosystems. © 2020, Pleiades Publishing, Ltd