Oak Forest Soils Research Articles

Revising the role of belowground fungi in pentachlorophenol pollution management: insights from Tunisian cork oak forests

This summarizes the doctoral thesis “Belowground fungi are key sentinels in forest soils vulnerable to pentachlorophenol pollution: a mechanistic study in Quercus suber forests”. The PhD degree was awarded by ITQB NOVA in March 2018. It comprises a revision of the major issues, objectives, methodology and results, as well as a few possible recommendations for future work on bioremediation of halogenated aromatic pollutants. The working hypothesis of the thesis proposed that soils in Tunisian cork oak forests are likely contaminated with pentachlorophenol (PCP), a persistent organic pollutant (POP). This hypothesis is based on frequent reports of cork contamination with pentachloroanisole (PCA), which is likely formed through microbial conversion of PCP. Furthermore, PCP was considered a suitable model for investigating the role of soil mycobiota in pollution management due to its ability to travel long distances in the atmosphere, partition favourably into the soil layer, and moderate abiotic resistance, besides its life-threatening toxicity. Finally, fungi play a key role in colonizing soil in cork oak forests. These concepts have been applied in the "Preventive and remediation strategies for continuous elimination of polychlorinated phenols from forest soil" project (SfP-NATO 981674, 2006-2011). Overall the major findings of the study include the demonstration of the prevalence of PCP in the soils of Tunisian cork oak forests. Additionally, the study elucidated both the significance and impact of fungal activity in the mitigation and dispersion of PCP.

Scleromatobacter humisilvae gen. nov., sp. nov., a novel bacterium isolated from oak forest soil.

A novel bacterial strain, designated BS-T2-15T, isolated from forest soil in close proximity to decaying oak wood, was characterized using a polyphasic taxonomic approach. Phylogenetic analyses based on 16S rRNA gene sequences as well as phylogenomic analyses based on coding sequences of 340 concatenated core proteins indicated that strain BS-T2-15T forms a distinct and robust lineage in the Rubrivivax-Roseateles -Leptothrix-Azohydromonas -Aquincola-Ideonella branch of the order Burkholderiales. The amino acid identity and the percentage of conserved proteins between the genome of strain BS-T2-15T and genomes of closely related type strains ranged from 64.27 to 66.57% and from 40.89 to 49.27 %, respectively, providing genomic evidence that strain BS-T2-15T represents a new genus. Its cells are Gram-stain-negative, aerobic, motile by a polar flagellum, rod-shaped and form incrusted white to ivory colonies. Optimal growth is observed at 20-22 °C, pH 6 and 0% NaCl. The predominant fatty acids of strain BS-T2-15T are C16 : 1 ω7c, C16 : 0 and C14 : 0 2-OH. Its polar lipid profile consists of a mixture of phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol and its main respiratory quinone is ubiquinone 8. The estimated size of its genome is 6.28 Mb with a DNA G+C content of 69.56 mol%. Therefore, on the basis of phenotypic and genotypic properties, the new strain BS-T2-15T represents a novel genus and species for which the name Scleromatobacter humisilvae gen. nov., sp. nov., is proposed. The type strain is BS-T2-15T (DSM 113115T=UBOCC-M-3373T).

Changes in Soil Ectomycorrhizal Fungi Community in Oak Forests along the Urban–Rural Gradient

The ectomycorrhizal fungi communities of forests are closely correlated with forest health and ecosystem functions. To investigate the structure and composition of ectomycorrhizal fungi communities in oak forest soil and their driving factors along the urban–rural gradient, we set up a Quercus acutissima forest transect and collected samples from the center to the edge of Jinan city (urban, suburban, rural). The results showed that the ectomycorrhizal fungal community composition at the phyla level mainly included Basidiomycota and Ascomycota in three sites. At the genus level, the community compositions of ectomycorrhizal fungi, along the urban–rural gradient, exhibited significant differences. Inocybe, Russula, Scleroderma, Tomentella, Amanita and Tuber were the dominant genera in these Quercus acutissima forests. Additionally, the diversity of ectomycorrhizal fungi was the highest in rural Quercus acutissima forest, followed by urban and suburban areas. Key ectomycorrhizal fungi species, such as Tuber, Russula and Sordariales, were identified among three forests. We also found that pH, soil organic matter and ammonium nitrogen were the main driving factors of the differences in ectomycorrhizal fungi community composition and diversity along the urban–rural gradient. Overall, the differences in composition and diversity in urban–rural gradient forest were driven by the differences in soil physicochemical properties resulting from the forest location.

Annual and seasonal variations in soil volatile organic compound concentrations in a Mediterranean shrubland and holm oak forest

Soil biogenic volatile organic compounds (VOCs) play an important role in soil ecology and function and may affect atmospheric chemistry. While previous studies of soil VOCs have predominantly measured surface flux exchange rates, VOC concentrations within the surface soil layer are largely unknown, especially in Mediterranean ecosystems. In this study, we measured seasonal and annual concentrations of soil VOCs in a Mediterranean shrubland and a holm oak forest over the period 2014–2016. Soil CO2 efflux, and soil enzyme and plant activities were measured as explanatory variables of soil VOC concentrations. There were greater total soil VOC concentrations in the shrubland (3.66 ± 1.01 ppb) than the holm oak forest (2.23 ± 0.51 ppb) across the study period. There were the greatest concentrations of monoterpenes (0.85 ± 0.43 ppb) and methanol (0.81 ± 0.20 ppb) in the shrubland and forest, respectively, and concentrations of methanol, acetic acid, formaldehyde, ethanol, and acetaldehyde were the dominant compounds in both ecosystems (>0.1 ppb). Although concentrations of some VOCs in both ecosystems were highest and lowest in spring and winter, respectively, the variability of other VOCs depended on compound and ecosystem. Soil temperature and water content, CO2 efflux, and enzyme activity were the best explanatory variables for variation in soil VOC concentrations in the two ecosystems: there was a stronger association between concentration of dominant compounds, except formaldehyde, with soil temperature and/or CO2 efflux than with soil water content. Activity of C- and N-degrading enzymes was positively associated with the concentration of VOCs, depending on ecosystem, and consistently correlated with high soil water content. In the holm oak forest soils, net photosynthetic rate (A) was positively correlated with soil concentration of monoterpenes. These results show that soil VOC concentrations in these Mediterranean ecosystems are driven by soil temperature and water content, and microbial activity, in combination with ecosystem plant activity. It is thus likely that projected climate change increases in temperature increase soil VOC concentrations and lead to increases in emissions to the atmosphere; however, microbial production and consumption of soil VOCs may be modulated by soil water content.

Survival Rate, Chemical and Microbial Properties of Oak Seedlings Planted with or without Oak Forest Soils in a Black Locust Forest of a Dryland

Native tree species are frequently unable to effectively grow in non-native tree cultivation scenarios. In the Loess Plateau, China, it is difficult to find native oak (Quercus liaotungensis) seedlings in non-native black locust forests. Black locust is an arbuscular mycorrhizal (AM) tree, but oak is an ectomycorrhizal (ECM) tree. Plants highly depend on their symbiotic mycorrhizal fungi to take up water, nitrogen (N) and other nutrients. We hypothesized that black locust forests would not provide ECM inoculum to oak seedlings, limiting their water and nutrient uptake, which would be improved by ECM inoculum. Here, we (1) sowed seeds, with or without oak forest soils, (2) transplanted seedlings collected in oak forests, with or without oak forest soils, and (3) planted seedlings germinated in autoclaved or unautoclaved oak forest soils. We measured the survival and growth rate for all three experiments, along with chemical properties, and root ECM colonization. Oak seeds sowed with oak forest soils had higher mycorrhizal colonization, leaf N concentrations and survival rate, and lower root δ13C than the seeds sowed without oak forest soils. Planting with oak forest soils also increased the survival rate of the germinated seedlings, but not the transplanted seedlings. Overall, our study suggested that the use of oak forest soils in the black locust forest to improve the water and N uptake of oak seedlings by providing the ECM inoculum, resulting in a high survival rate. Our study also implies that the method of sowing seeds was effortless and effectively compared to transplanting wild/nursery seedlings.

Characterization of Bradyrhizobium spp. Nodulating Lupinus cosentinii and L. luteus Microsymbionts in Morocco

In this work, we analyzed the diversity of the nodule-forming bacteria associated with Lupinus luteus and Lupinus cosentinii grown in the Maamora Cork oak forest acidic soils in Morocco. The phenotypic analysis showed the high diversity of the strains nodulating the two lupine's species. The strains were not tolerant to acidity or high alkalinity. They do not tolerate salinity or high temperatures either. The strains isolated from L. luteus were more tolerant to antibiotics and salinity than those isolated from L. cosentinii. The plant growth promoting (PGP) activities of our strains are modest, as among the 28 tested isolates, only six produced auxins, six produced siderophores, whereas three solubilized phosphates. Only two strains possess the three activities. The rrs gene sequences from eight representative strains selected following ARDRA and REP-PCR results revealed that they were members of the genus Bradyrhizobium. Six strains were then retained for further molecular analysis. The glnII, recA, gyrB, dnaK, and rpoB housekeeping gene sequence phylogeny showed that some strains were close to B. lupini LMG28514T whereas others may constitute new genospecies in the genus Bradyrhizobium. The strains were unable to nodulate Glycine max and Phaseolus vulgaris and effectively nodulated L. luteus, L. cosentinii, L. angustifolius, Chamaecytisus albidus, and Retama monosperma. The nodC and nodA symbiotic gene phylogenies showed that the strains are members of the genistearum symbiovar.

Comparison between Mineralogical Properties of Oak Forest and Un-Cultivated Soils in Iraqi Kurdistan Region

This study was conducted to identify the mineralogical properties of oak forest and uncultivated soils at 12 locations in the Iraqi Kurdistan region, which included (Brifca, Gara, and Matin) in Duhok governorate, (Awagrd, Bilah, and Malakan) in Erbil governorate, (Badawan, Bardanga, and Chwarta) in Sulaimani Governorate and (Bakhakon, Hawar, and Sartak) in Halabja governorate. Clay minerals were identified from X-ray diffraction data and peaks. Peak height is used as a rough indicator of the relative abundance of minerals. In general, the expansion of 14°A to 17°A in the ethylene glycol treatment was not detected because measuring started at 5? so that’s why we cannot differentiate between Chlorite and Smectite in that treatment. Swelling chlorite was the dominant mineral in these soils. While the miner clay minerals at those locations were Kaolinite. Mica was identified at all locations, while the dominant type of mica in forest soils was Muscovite, which was obtained from 6 sites, and Mica Biotite was obtained from 4 sites. In uncultivated sites, both types of mica were recorded at 5 sites.

Not all long-distance-exploration types of ectomycorrhizae are the same: differential accumulation of nitrogen and carbon in Scleroderma and Xerocomus in response to variations in soil fertility

Long-distance-exploration type (LDET) ectomycorrhizae have been reported to be best adapted to infertile soils, but variation within LDET ectomycorrhizae have not been thoroughly examined. Concentrations of nitrogen (N) and carbon (C) in LDET ectomycorrhizae were examined in Xerocomus-Pinus sylvestris and Scleroderma-Quercus petraea ectomycorrhizae. The study determined how concentrations of these elements vary in ectomycorrhizae in fertile (organic, uppermost mineral) and infertile (brunic) soil layers. The organic horizon in both Scots pine and sessile oak forest soils had the highest mineral status and exchange cations. In contrast, low mineral concentrations, high base saturation, and pH were characteristic of the brunic horizon in both forest stands. Xerocomus ectomycorrhizae had a higher concentration of N in the fertile (organic and uppermost mineral) soil horizons (3.4%) than in the infertile (brunic) soil horizon (2.2%). N concentration in Scleroderma ectomycorrhizae varied from 2.8%-3.0 % and did not differ between the studied soil horizons. The mean concentration of carbon in Xerocomus ectomycorrhizae varied from 29%-46% in Scots pine stands and from 41%-44% in Scleroderma ectomycorrhizae in sessile oak stands. The concentration of carbon in both Xerocomus and Scleroderma ectomycorrhizae was significantly higher in the fertile horizons (organic and uppermost mineral) compared to the brunic (infertile) horizon. In summary, the analysis conducted in the present study indicates that the LDET ectomycorrhizae, Xerocomus and Scleroderma, possess inherent variations in C and N content to manage soil resources.

Comparison between Mineralogical Properties of Oak Forest and Un-Cultivated Soils in Iraqi Kurdistan Region

This study was conducted to identify the mineralogical properties of oak forest and un-cultivated soils at 12 locations in the Iraqi Kurdistan region, which included (Brifca, Gara, and Matin) in Duhok governorate, (Awagrd, Bilah, and Malakan) in Erbil governorate, (Badawan, Bardanga, and Chwarta) in Sulaimani Governorate and (Bakhakon, Hawar, and Sartak) in Halabja governorate. Clay minerals were identified from X-ray diffraction data and peaks. Peak height is used as a rough indicator of the relative abundance of minerals. In general, the expansion of 14A to 17A in ethylene glycol treatment was not detected because measuring started from 5 so thats why we cannot be differentiated between Chlorite and Smectite in that treatment. Swelling chlorite was the dominant mineral in these soils. While the miner clay mineral at that locations were Kaolinite. Mica was identified at all locations, while the dominant type of Mica at forest soils was Muscovite which was obtained from 6 sites, while Mica Biotite was obtained from 4 sites, but in un-cultivated sites, both types of mica recorded at 5 sites.

Amynthas spp. impacts on seedlings and forest soils are tree species-dependent

Asian jumping worms (Amynthas spp.) are recent invaders of Upper Midwest forests. Research has highlighted the impacts of Amynthas earthworms on soil biogeochemistry and structure, and field observations suggest that Amynthas spp. decrease litter horizon depth and alter plant communities. However, the extent to which Amynthas spp. effects vary among forest types and with worm density and the mechanisms driving these effects are unknown. We conducted a 3-month tree seedling study to evaluate the effects of Amynthas spp. on tree seedling growth and a mesocosm field experiment to evaluate Amynthas spp. effects on soil carbon and nutrient cycling, soil structure, and leaf litter decomposition rates across forest types. In the seedling study, Amynthas spp. enhanced the growth of sugar maple and European buckthorn seedlings and decreased the growth of white oak seedlings. These effects were due to Amynthas spp.-induced changes in soil properties. In the mesocosm study, as Amynthas spp. density increased, carbon mineralization and carbon, nitrogen, and phosphorus availability increased in white oak forest soils and decreased in sugar maple forest soils, while decomposition rates of European buckthorn litter increased as Amynthas spp. density increased. Amynthas spp. altered soil structure similarly across all forest soil types. Taken together, our results suggest that Amynthas spp. have the potential to alter forest ecosystem dynamics via feedbacks among tree species, seedlings, and soil biogeochemistry. However, Amynthas spp. effects on tree seedlings and forest soils are largely context-dependent, and the direction and magnitude of these effects are mediated by tree species.

Soil energy potential in the coniferous and broadleaf forests of Holosiivskyi National Nature Park

The article presents the results of three-year studies of the energy reserve of soils of pine and oak forests of the Holosiivskyi National Nature Park. Soils largely reflect the state of many internal processes in forest ecosystems. The most important for the ecosystem sustainability is the soil content of organic matter, which determines the energy potential of the soil, and its fertility. The aim of the study was to investigate the energy reserve gradient in depth in oak and pine forests by organic matter content, to compare the effect of two different types of forest phytocenoses on soil energy potential as an important indicator of ecosystem stability. Soil profiles were investigated, in which 7 horizons of soil were isolated in the oak forest, and only 4 were clearly identified in the pine forest. Tests for carbonates and clay loam showed sod-podzolic gley soil in an oak forest and sod-hidden podzolic soil in pine forest with poorly expressed soil horizons. Soil energy potential was determined The soil energy gradient in soils is distributed with a decrease from the upper horizon to the lower in both oak and pine forests. The upper humus horizon in the pine forest was richer in organic matter than the humus horizon in the oak forest. At the same time, in the pine forest soils the sharpest decrease of organic matter with depth was observed. The deciduous forest phytocenoses provided a larger and more uniformly distributed organic matter stock in the soil horizons. Comparing the energy reserve of broadleaf and coniferous forest phytocenoses soils, differences in the soil horizons, which amounted to 189506.9 kJ/m3 between humus A1 horizons in both forests, were 24 %. The difference between the eluvial horizons was 32216.2 kJ/m3 – 9 %, the difference between the eluvial horizons – 23747.1 kJ/m3 – 8 %, and the difference between the soil-forming horizons of 3018.7 kJ/m3 – 1.6 %. The study confirmed the importance of determining the energy potential of soils to assess the stability of phytocenoses.Manuscript received 21.04.2020

Long-term drought decreases ecosystem C and nutrient storage in a Mediterranean holm oak forest

Aridity has increased in recent decades in the Mediterranean Basin and is projected to continue to increase in the coming decades. We studied the consequences of drought on the concentrations, stoichiometries and stocks of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) in leaves, foliar litter of a three dominant woody species and soil of a Mediterranean montane holm oak forest where soil-water content was experimentally reduced (15 % lower than the control plots) for 15 years. Nitrogen stocks were lower in the drought plots than in the control plots (8.81 ± 1.01 kg ha−1 in the forest canopy and 856 ± 120 kg ha−1 in the 0−15 cm soil layer), thus representing 7 and 18 % lower N stocks in the canopy and soil respectively. δ15N was consistently higher under drought conditions in all samples, indicating a general loss of N. Foliar C and K stocks were also lower but to a lesser extent than N. Decreases in biomass and C and N stocks due to drought were smallest for the most dominant tall shrub, Phillyrea latifolia, so our results suggest a lower capacity of this forest to store C and nutrients but also substantial resulting changes in forest structure with increasing drought.

Litterfall Hg deposition to an oak forest soil from southwestern Europe

Litterfall constitutes one of the main vectors for mercury (Hg) transfer to forested ecosystems, so we studied the deposition of Hg through senescent vegetation (oak leaves, twigs and miscellaneous) in a deciduous forest plot of Southwest Europe dominated by Quercus robur in 2015 and 2016. Total Hg concentrations increased in the following order: bole wood (1.4 μg kg−1) < bark (8.3 μg kg−1) < twigs (12.2 μg kg−1) < miscellaneous (36.0 μg kg−1) < oak leaves (39.3 μg kg−1) < mineral soil (42.4 μg kg−1) < Oi horizons (48.7 μg kg−1) < Oe + Oa horizons (71.6 μg kg−1). Mercury accumulation rates in oak leaves during the growing season were 0.15–0.18 μg kg−1 day−1. Mercury deposition fluxes were 26 and 21 μg m−2 yr−1 for 2015 and 2016, respectively, with oak leaves being the fraction that contributed the most. Mercury determination in litterfall sorted biomass fractions lead to a more accurate estimation of the total annual Hg deposition fluxes through litterfall. Higher Hg content was obtained for organic horizons (average of 60.2 μg kg−1) than for mineral soil (mean of 42.4 μg kg−1), but the soil Hg pool was higher in the latter. The results confirmed the necessity of taking into account the Hg pool in the deeper mineral soil layers as they accumulate substantial quantities of Hg associated to organic C and Al compounds, preventing its mobilization to other compartments of the terrestrial ecosystems.

Bacterial Communities on the Surface of the Mineral Sandy Soil from the Desert of Maine (USA).

The Desert of Maine, not a real desert, is a 160,000 m2 tourist attraction of glacial silt which resembles a desert, surrounded by a pine forest in the state of Maine located in the northeastern USA. Though not a true desert, the soil of the Desert of Maine has a sandy texture with poor water-holding abilities, nutrient retention capabilities, and a relatively low pH value (pH 5.09). Samples from this site may be of interest to examine the bacterial diversity present on mineral sandy loam soils with an acidic pH, low concentrations of organic materials though surrounded by a pine forest, and compare it with true desert soil microbial populations. Two surface sand samples from the Desert of Maine were obtained, and pyrosequencing of PCR amplified 16S rRNA genes from total extracted DNA was used to assess bacterial diversity, community structure, and the relative abundance of major bacterial taxa. We found that the soil samples from the Desert of Maine displayed high levels of bacterial diversity, with a predominance of members belonging to the Proteobacteria and Actinobacteria phyla. Bacteria from the most abundant genus, Acidiphilium, represent 12.5% of the total 16S rDNA sequences. In total, 1394 OTUs were observed in the two samples, with 668 OTUs being observed in both samples. By comparing Desert of Maine bacterial populations with studies on similar soil environments, we found that the samples contained less Acidobacteria than soils from acid soil forests, and less Firmicutes plus more Proteobacteria than oligotrophic desert soils. Interestingly, our samples were found to be highly similar in their composition to an oak forest soil in France.

Diversity of Naked Amoebae in Soils of Forest Areas of Zhytomyr Region (Ukraine).

Here we consider the morphotypes and changing species composition of naked amoebae in soils of forest areas in Zhytomyr region (Ukraine). The species composition and morphotypes of amoebae are influenced by the microclimate of soil and litter. Complexes of naked amoebae in the study area constitute two clusters: one of broadleaf (oak) and mixed forests, another of coniferous forests. The most similar species compositions were found in soils of oak and mixed forests (64 % similarity). The least similar were amoebae complexes of coniferous forests and oak forests, and coniferous forests and mixed forests. Non-parametric multidimensional scaling (MDS) showed that species complex of amoebae of mixed forests and oak forests had moister and more acidic soils compared to coniferous forests.

Soil microbial diversity drops with land-use change in a high mountain temperate forest: a metagenomics survey.

Land-use change has been identified as the most severe threat to biodiversity. Soils are important biodiversity reservoirs, but to what extent conversion of high-altitude temperate forest to arable land affects taxonomic and functional soil biodiversity is still largely unknown. Shotgun metagenomics was used to determine the taxonomic and functional diversity of bacteria, archaea and DNA virus in terms of effective number of species in high-altitude temperate oak and pine-oak forest and arable soils from Mexico. Generally, the soil ecosystem maintained its microbial species richness notwithstanding land-use change. Archaea diversity was not affected by land-use change, but the bacterial diversity decreased with 45-55% when the oak forest was converted to arable land and 65-75% when the pine-oak forest was. Loss in bacterial diversity as a result of land-use change was positively correlated (R2 = 0.41) with the 10-25% loss in functional diversity. The archaeal communities were evener than the bacterial ones, which might explain their different response to land-use change. We expected a decrease in DNA viral communities as the bacterial diversity decreased, i.e. their potential hosts. However, a higher viral diversity was found in the arable than in the forest soils. It was found that converting high altitude oak and pine-oak forests to arable land more than halved the bacterial diversity, but did not affect the archaeal and even increased the viral diversity.

COMPARISON BETWEEN CHEMICAL AND MINERALOGICAL PROPERTIES OF OAK FOREST AND BARE CULTIVATED SOILS IN IRAQI KURDISTAN REGION

This study was conducted during 1/7/2016 to 20/12/2018, which aimed to determine chemical and mineralogical properties of oak forest and bare cultivated soils at 6 locations in Iraqi Kurdistan region, the samples were collected from two depths (0 – 30) and (30 – 60) cm. The study included some chemical and physical properties and identification of clay minerals from X-ray diffraction data. Peak height is used as a rough indicator of relative abundance of minerals. In general, the expansion of 14°A to ≈ 17°A in ethylene glycol treatment was not detected because measuring started from 5θ so that’s why we cannot differentiated between Chlorite and Semectite in that treatment. The main results indicated that the organic matter, clay content and CEC values in forest soils were higher than their values in bare cultivated soils, swelling chlorite being the dominant mineral in these soils. While the miner clay mineral at that locations were Kaolinite. Mica was identified at all location, while the dominant type of Mica at forest soils was Muscovite which was obtained from 4 Locations, while Mica Biotite was dominant in bare cultivated soils which was obtained from 4 sites.

Survival of Brenneria goodwinii and Gibbsiella quercinecans, associated with acute oak decline, in rainwater and forest soil

Acute oak decline (AOD) affects native UK oak species causing rapid decline and mortality in as little as five years. A major symptom of AOD is black weeping stem lesions associated with bacterial phytopathogens, Brenneria goodwinii and Gibbsiella quercinecans. However, there is limited knowledge on the ecological and environmental reservoirs of these phytopathogens. Rainwater and soils are common reservoirs of plant pathogens in a forest environment; therefore, the aim of this study was to investigate the survival of B. goodwinii and G. quercinecans in vitro when inoculated into rainwater and forest soil using a combination of agar-based colony counts and gyrB gene-targeted quantitative PCR (qPCR). Brenneria goodwinii lost viability on inoculation into soil and rainwater, but was detectable at low abundance in soil for 28 days using qPCR, suggesting a limited ability to persist outside of the host, potentially in a viable but non-culturable (VBNC) state. Conversely, Gibbsiella quercinecans, was re-isolated from rainwater for the entire duration of the experiment (84 days) and was re-isolated from forest soil after 28 days, with qPCR analysis corroborating these trends. These data demonstrate that B. goodwinii is unable to survive in forest soils and rainwater, suggesting that it may be an endosymbiont of oak trees, whereas G. quercinecans remains viable in soil and rainwater biomes, suggesting a broad ecological distribution. These data advance understanding of the potential epidemiology of AOD-associated bacteria and their ecological reservoirs, thus increasing the overall knowledge of the pathology of AOD, which assists the development of future management strategies.

An environmentally friendly method for the determination of polycyclic aromatic hydrocarbons in different soil typologies

Environmental contextPolycyclic aromatic hydrocarbons (PAHs) are widespread organic pollutants that tend to accumulate in soil. We developed an environmentally friendly analytical method for PAHs to evaluate human health risks associated with their presence in soils. The method is feasible for the analysis of soils with widely varying PAH contamination levels, and is well suited to environmental monitoring studies of relevance to human health. AbstractA microwave-assisted extraction, with a dispersive solid-phase purification step followed by programmed temperature vaporisation–gas chromatography–tandem mass spectrometry, is proposed as an environmentally friendly, simple and cheap analytical method for polycyclic aromatic hydrocarbons (PAHs) in soil. Different extraction and clean-up operating variables were tested to achieve satisfactory analytical performances: trueness from 92 to 114%, limit of quantification (LOQ) from 0.4 to 2µgkg−1 for most PAHs and intermediate precision, calculated as relative standard deviation (RSD), below 10%. The method was validated using both Certified Reference Material and real soil samples collected at sites subjected to different human activities. PAH contents ranged from 0.11 (in holm oak forest soil) to 1mgkg−1 d.w. (in an industrial soil) according to the anthropic gradient. The soil PAH contents measured were used to estimate the risk to human health, which suggested the exposure to the PAHs in soil as a potential risk for human health, especially at the industrial site. The feasibility of the method for soils with different PAH contamination degrees makes it relevant in monitoring programs.

Physico-chemical characterization of Oak, Pine and Sal forest soil profiles of Betalghat Region of Kumaun Himalaya

Soil is one of the basic natural resources on which all forms of terrestrial life co-exist. The soils of three forest types i.e., banj-oak ( Quercus leucotrichophora A. Camus) chir-pine ( Pinus roxburghii Sargent) and sal ( Shorea robusta Gaertn. f.) of Betalghat block, Nainital District, (Kumaun Himalaya). Soils were drawn from three depths viz. 0-10 cm, 11-20 cm, 21-30 cm. The present study were studied resulted to soil physico-chemical properties i.e. maximum soil texture (sand 34.30 %, silt 57.21 % and clay 33.23 %), soil moisture ( 12.6 %), bulk density ( 1.43 g.cm -3 ), porosity ( 52.06 %), water holding capacity ( 69.27 %) and the maximum values of chemical analysis i.e. pH ( 6.80 ), total carbon ( 3.82 %), organic matter (6.57 %), total nitrogen ( 0.36 % ), available potassium ( 267 mg/kg ) and available phosphorous ( 62 mg/kg ). Banj-oak forest shows rich physical properties followed by sal and chir-pine forest while chir-pine forest shows rich chemical properties in compared to sal and banj-oak forest.