scholarly journals Rhizosphere Bacterial Networks, but Not Diversity, Are Impacted by Pea-Wheat Intercropping

2021 ◽  
Vol 12 ◽  
Author(s):  
Barbara Pivato ◽  
Amélie Semblat ◽  
Thibault Guégan ◽  
Samuel Jacquiod ◽  
Juliette Martin ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Plant Species ◽  
Ecological Processes ◽  
Niche Complementarity ◽  
Beneficial Effects ◽  
Sole Cropping ◽  
Chemical Inputs ◽  
Occurrence Pattern ◽  
Open Question ◽  
The Impact

Plant-plant associations, notably cereal-legume intercropping, have been proposed in agroecology to better value resources and thus reduce the use of chemical inputs in agriculture. Wheat-pea intercropping allows to decreasing the use of nitrogen fertilization through ecological processes such as niche complementarity and facilitation. Rhizosphere microbial communities may account for these processes, since they play a major role in biogeochemical cycles and impact plant nutrition. Still, knowledge on the effect of intecropping on the rhizosphere microbiota remains scarce. Especially, it is an open question whether rhizosphere microbial communities in cereal-legume intercropping are the sum or not of the microbiota of each plant species cultivated in sole cropping. In the present study, we assessed the impact of wheat and pea in IC on the diversity and structure of their respective rhizosphere microbiota. For this purpose, several cultivars of wheat and pea were cultivated in sole and intercropping. Roots of wheat and pea were collected separately in intercropping for microbiota analyses to allow deciphering the effect of IC on the bacterial community of each plant species/cultivar tested. Our data confirmed the well-known specificity of the rhizosphere effect and further stress the differentiation of bacterial communities between pea genotypes (Hr and hr). As regards the intercropping effect, diversity and structure of the rhizosphere microbiota were comparable to sole cropping. However, a specific co-occurrence pattern in each crop rhizosphere due to intercropping was revealed through network analysis. Bacterial co-occurrence network of wheat rhizosphere in IC was dominated by OTUs belonging to Alphaproteobacteria, Bacteroidetes and Gammaproteobacteria. We also evidenced a common network found in both rhizosphere under IC, indicating the interaction between the plant species; this common network was dominated by Acidobacteria, Alphaproteobacteria, and Bacteroidetes, with three OTUs belonging to Acidobacteria, Betaproteobacteria and Chloroflexi that were identified as keystone taxa. These findings indicate more complex rhizosphere bacterial networks in intercropping. Possible implications of these conclusions are discussed in relation with the functioning of rhizosphere microbiota in intercropping accounting for its beneficial effects.

scholarly journals Stability of microbiota in vineyard soils across consecutive years.

2021 ◽  
Author(s):  
Alessandro Cestaro ◽  
emanuela coller ◽  
Davide Albanese ◽  
erika stefani ◽  
Massimo Pindo ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Large Scale ◽  
Geographic Origin ◽  
Soil Microbial Communities ◽  
Geographical Location ◽  
Taxonomic Structure ◽  
Ecological Processes ◽  
Soil Microbiota ◽  
Soil Microbial ◽  
The Impact

Agricultural soils harbor rich and diverse microbial communities that have a deep influence on soil properties and productivity. Large scale studies have shown the impact of environmental parameters like climate or chemical composition on the distribution of bacterial and fungal species. Comparatively, little data exists documenting how soil microbial communities change between different years. Quantifying the temporal stability of soil microbial communities will allow us to better understand the relevance of the differences between environments and their impact on ecological processes on the global and local scale. We characterized the bacterial and fungal components of the soil microbiota in ten vineyards in two consecutive years. Despite differences of species richness and diversity between the two years, we found a general stability of the taxonomic structure of the soil microbiota. Temporal differences were smaller than differences due to geographical location, vineyard land management or differences between sampling sites within the same vineyard. Using machine learning, we demonstrated that each site was characterized by a distinctive microbiota, and we identified a reduced set of indicator species that could classify samples according to their geographic origin across different years with high accuracy.

scholarly journals Rewiring of peatland plant-microbe networks outpaces species turnover

2020 ◽  
Author(s):  
Bjorn J.M. Robroek ◽  
Magalí Martí ◽  
Bo H. Svensson ◽  
Marc G. Dumont ◽  
Annelies J. Veraart ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Species Turnover ◽  
Ecosystem Processes ◽  
Microbial Interactions ◽  
Ecosystem Dynamics ◽  
Bipartite Networks ◽  
Ecological Processes ◽  
Network Composition ◽  
The Impact ◽  
Network Rewiring

AbstractEnviro-climatological changes are thought to be causing alterations in ecosystem processes through shifts in plant and microbial communities; however, how links between plant and microbial communities change with enviro-climatological change is likely to be less straightforward but may be fundamental for many ecological processes. To address this, we assessed the composition of the plant community and the prokaryotic community –using amplicon-based sequencing– of three European peatlands that were distinct in enviro-climatological conditions. Bipartite networks were used to construct site-specific plant-prokaryote co-occurrence networks. Our data show that between sites, plant and prokaryotic communities differ and that turnover in interactions between the communities was complex. Essentially, turnover in plant-microbial interactions is much faster than turnover in the respective communities. Our findings suggest that network rewiring does largely result from novel associations between species that are common and shared across the networks. Turnover in network composition is largely driven by novel interactions between a core community of plants and microorganisms. Taken together our results indicate that plant-microbe associations are context dependent, and that changes in enviro-climatological conditions will likely lead to network rewiring. Integrating turnover in plant-microbe interactions into studies that assess the impact of enviro-climatological change on peatland ecosystems is essential to understand ecosystem dynamics and must be combined with studies on the impact of these changes on ecosystem processes.

scholarly journals Monitoring Re-Growth of Invasive Plants Using an Autonomous Surface Vessel

2021 ◽  
Vol 7 ◽  
Author(s):  
Robert Codd-Downey ◽  
Michael Jenkin ◽  
Bir Bikram Dey ◽  
James Zacher ◽  
Eva Blainey ◽  
...  
Keyword(s):  
Plant Species ◽  
Position Estimation ◽  
Depth Information ◽  
Environmental Sensors ◽  
Invasive Aquatic Plant ◽  
Hull Design ◽  
Rtk Gps ◽  
Open Question ◽  
The Impact ◽  
Surface Vessel

Invasive aquatic plant species, and in particular Eurasian Water-Milfoil (EWM), pose a major threat to domestic flora and fauna and can in turn negatively impact local economies. Numerous strategies have been developed to harvest and remove these plant species from the environment. However it is still an open question as to which method is best suited to removing a particular invasive species and the impact of different lake conditions on the choice. One problem common to all harvesting methods is the need to assess the location and degree of infestation on an ongoing manner. This is a difficult and error prone problem given that the plants grow underwater and significant infestation at depth may not be visible at the surface. Here we detail efforts to monitor EWM infestation and evaluate harvesting methods using an autonomous surface vessel (ASV). This novel ASV is based around a mono-hull design with two outriggers. Powered by a differential pair of underwater thrusters, the ASV is outfitted with RTK GPS for position estimation and a set of submerged environmental sensors that are used to capture imagery and depth information including the presence of material suspended in the water column. The ASV is capable of both autonomous and tele-operation.

Phytoremediation of landfill leachate in constructed wetland

2019 ◽  
pp. 441-446
Author(s):  
Jaak Truu ◽  
Jaanis Juhanson ◽  
Mait Kriipsalu ◽  
Marit Seene
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Plant Species ◽  
Landfill Leachate ◽  
Water Samples ◽  
Free Water ◽  
Vegetation Period ◽  
Quality Of Water ◽  
Remediation Plan ◽  
The Impact

The integrated remediation plan of the Laguja landfill, Estonia, includes creation of aconstructed wetland for treatment of landfill leachate. A mesocosm experiment wasconducted in order to estimate the impact of different plant species on purification efficiencyof wetland. The quality of water in mesocosms was monitored during vegetation period. Allplant treatments enhanced reduction of organic matter (BOD: 87-96%, COD: ca 30%, TOC:ca 50%) as well as ammonia and total nitrogen in water compared to unplanted control.Presence of plants enhanced biodegradative bacterial abundance and activity as well asmetabolic diversity of microbial community in water. Water samples from all plant treatmentswere characterized by distinct microbial communities as revealed by molecular fingerprintingtechniques. Most different from the rest of microbial communities were water samples frommesocosm with plants on floating mats. Our results show that in free-water constructedwetlands with vegetation the purification efficiency is not dependent on plant species, whilestructure of water microbial community differs due to plant species.

scholarly journals Ecological stochasticity and phage induction diversify bacterioplankton communities at the microscale

2021 ◽  
Author(s):  
Rachel E. Szabo ◽  
Sammy Pontrelli ◽  
Jacopo Grilli ◽  
Julia A. Schwartzman ◽  
Shaul Pollak ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Large Scale ◽  
Natural Populations ◽  
Natural Environments ◽  
Biological Interactions ◽  
Ecological Processes ◽  
Shotgun Metagenomics ◽  
Wide Range ◽  
Resource Patches ◽  
The Impact

In many natural environments, microorganisms self-assemble around heterogeneously distributed resource patches. The growth and collapse of populations on resource patches can unfold within spatial ranges of a few hundred micrometers or less, making such microscale ecosystems hotspots of biological interactions and nutrient fluxes. Despite the potential importance of patch-level dynamics for the large-scale evolution and function of microbial communities, we have not yet been able to delineate the ecological processes that control natural populations at the microscale. Here, we addressed this challenge in the context of microbially-mediated degradation of particulate organic matter by characterizing the natural marine communities that assembled on over one thousand individual microscale chitin particles. Through shotgun metagenomics, we found significant variation in microscale community composition despite the similarity in initial species pools across replicates. Strikingly, a subset of particles was highly populated by rare chitin-degrading strains; we hypothesized that their conditional success reflected the impact of stochastic colonization and growth on community assembly. In contrast to the conserved functional structures that emerge in ecosystems at larger scales, this taxonomic variability translated to a wide range of predicted chitinolytic abilities and growth returns at the level of individual particles. We found that predation by temperate bacteriophages, especially of degrader strains, was a significant contributor to the variability in the bacterial compositions and yields observed across communities. Our study suggests that initial stochasticity in assembly states at the microscale, amplified through biotic interactions, may have significant consequences for the diversity and functionality of microbial communities at larger scales.

HBOT Application at Cases of Gingival Inflammation

2019 ◽  
Author(s):  
Ilma Robo
Keyword(s):  
Root Resorption ◽  
Periodontal Diseases ◽  
Therapeutic Effects ◽  
Clinical Effects ◽  
Gingival Inflammation ◽  
Beneficial Effects ◽  
New Therapeutic Approaches ◽  
Short Period ◽  
Mechanical Therapy ◽  
The Impact

The treatment of periodontal diseases, mainly of their origin, with the most common clinical manifestation in form of gingival inflammation, is manifold and powerful, including: mechanical therapy, antibiotic, antiseptic and various approaches to treatment, which are recommended to be used within a short period of time. New therapeutic approaches have been proven as alternative treatment to conventional therapy, or in combination with conventional therapies, to reduce the number of periodontopathic pathogens in gingival sulcus. HBOT has a detrimental effect on periodontal microorganisms, as well as beneficial effects on the healing of periodontal tissue, increasing oxygen pressure in gingival pockets. Our study is aimed at reviewing the current published literature on hyperbaric oxygen therapy and focuses on role of HBOT as a therapeutic measure for the individual with periodontal disease in general and for the impact on the recovery of gingival inflammation. HBOT and periodontal treatment together, reduce up to 99% of the gram-negative anaerobic load of subgingival flora. HBOT, significantly reduces subgingival anaerobic flora. Clinical effects in 2-year follow-up of treated patients are sensitive. Reduction of gingival hemorrhage indexes, depth of peritoneum, plaque index, occurs in cases of combination of HBOT and detraction. Reduced load persists up to 2 months after therapy. The significant increase in connective tissue removal starts at the end of 2nd week, to achieve the maximum in week 3-6 of application. HBOT used for re-implantation, stimulates the healing of periodontal membrane, pulp, prevents root resorption, healing of periodontal lining tissues. HBOT, significantly reduces the hemorrhage index with 1.2 value difference, 0.7mm probe depth, reduces gingival fluid by 2. HGH exposure is increased by gingival blood flow, with a difference of 2 in measured value. The therapeutic effects of HBOT in the value of the evaluation index can be saved up to 1-year post treatment.

Kalahari Cheetahs

2017 ◽  
Author(s):  
Gus Mills ◽  
Margaret Mills
Keyword(s):  
Reproductive Success ◽  
Spatial Ecology ◽  
Prey Selection ◽  
Arid Ecosystems ◽  
Foraging Success ◽  
Ecological Processes ◽  
Demographic Groups ◽  
Important Prey ◽  
Hunting Behaviour ◽  
The Impact

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.

Relation between cognitive disorders and type of physical activity: Results of the FréLE cohort

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
C Dupré ◽  
N Barth ◽  
A El Moutawakkil ◽  
F Béland ◽  
F Roche ◽  
...  
Keyword(s):  
Physical Activity ◽  
Cognitive Decline ◽  
Proportional Hazards ◽  
Cognitive Disorders ◽  
The Elderly ◽  
Cognitive Status ◽  
Global Test ◽  
Professional Activities ◽  
Beneficial Effects ◽  
The Impact

Abstract Background Few previous cohorts have studied the different type of physical activities and the degree of cognitive decline. The objective of this work was to analyze the leisure, domestic and professional activities with mild and moderate cognitive disorders in older people living in community. Methods The study used data from the longitudinal and observational study, FrèLE (FRagility: Longitudinal Study of Expressions). The collected data included: socio-demographic variables, lifestyle, and health status (frailty, comorbidities, cognitive status, depression). Cognitive decline was assessed by using: MMSE (Mini-Mental State Examination) and MoCA (Montreal Cognitive Assessment). MoCA was used with two cut-offs (26 and 17) so as to define mild and moderate cognitive disorders Physical activity was assessed by the PASE (Physical Activity Scale for the Elderly), structured in three sections: leisure, domestic and professional activities. Spline and proportional hazards regression models (Cox) were used to estimate the risk of cognitive disorders. Results At baseline, 1623 participants were included and the prevalence of cognitive disorders was 6.9% (MMSE) and 7.2% (MoCA), mild cognitive disorders was 71.3%. The mean age was 77 years, and 52% of the participants were women. After a 2 years long follow-up, we found 6.9% (MMSE) and 6% (MoCA) cognitive disorders on participants. Analyses showed that domestic activities were associated to cognitive decline (HR = 0.52 [0.28-0.94] for MMSE and HR = 0.48 [0.28-0.80] for MoCA). No association were found with leisure and professional activities, and no spline were significant with mild cognitive disorders. Conclusions Analysis showed a relationship between cognitive disorders and type of physical activity, thanks to the use of specific questionnaire of elderly and two global test of cognition. These findings will contribute to the debate on the beneficial effects of physical activity on cognition. Key messages This work allowed to compare two test of cognition and their link with physical activity. It contributes to the debate on the beneficial effects of physical activity on cognition. The work allowed us to see the effect of the different types of physical activity and the impact of the statistical method on the results.

scholarly journals Microstructure and Durability Performance of Mortars with Volcanic Powder from Calbuco Volcano (Chile) after 4 Hardening Years

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1751
Author(s):  
Rosa María Tremiño ◽  
Teresa Real-Herraiz ◽  
Viviana Letelier ◽  
José Marcos Ortega
Keyword(s):  
Water Absorption ◽  
Thermal Analyses ◽  
Length Change ◽  
Cement Industry ◽  
Chloride Diffusion ◽  
Beneficial Effects ◽  
State Diffusion ◽  
Calbuco Volcano ◽  
Reference Specimens ◽  
The Impact

One of the most popular ways to lessen the impact of the cement industry on the environment consists of substituting clinker by additions. The service life required for real construction elements is generally long, so it would be interesting to obtain information about the effects of new additions after a hardening period of several years. Analyzed here are the effects of the incorporation of volcanic ashes, coming from Calbuco volcano’s last eruption (Chile), as clinker replacement, in the durability and pore structure of mortars, after approximately 4 hardening years (1500 days), in comparison with reference specimens without additions. The substitution percentages of clinker by volcanic powder studied were 10% and 20%. The microstructure was characterized with mercury intrusion porosimetry and impedance spectroscopy. In order to evaluate the pozzolanic activity of the volcanic powder after 1500 days, differential thermal analyses were performed. Water absorption after immersion, steady-state diffusion coefficient and length change were also studied. In accordance with the results obtained, the 10% and 20% substitution of clinker by volcanic powder from the Calbuco volcano showed beneficial effects in the mortars after 4 years, especially regarding the microstructure and chloride diffusion, without noticeable influence in their water absorption.

Alkaline soil pH affects bulk soil, rhizosphere and root endosphere microbiomes of plants growing in a Sandhills ecosystem

2021 ◽  
Vol 97 (4) ◽  
Author(s):  
Lucas Dantas Lopes ◽  
Jingjie Hao ◽  
Daniel P Schachtman
Keyword(s):  
Microbial Communities ◽  
Plant Species ◽  
Soil Ph ◽  
Soil Microbial Communities ◽  
Bulk Soil ◽  
Strong Impact ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Soil Microbial ◽  
Soil Rhizosphere

ABSTRACT Soil pH is a major factor shaping bulk soil microbial communities. However, it is unclear whether the belowground microbial habitats shaped by plants (e.g. rhizosphere and root endosphere) are also affected by soil pH. We investigated this question by comparing the microbial communities associated with plants growing in neutral and strongly alkaline soils in the Sandhills, which is the largest sand dune complex in the northern hemisphere. Bulk soil, rhizosphere and root endosphere DNA were extracted from multiple plant species and analyzed using 16S rRNA amplicon sequencing. Results showed that rhizosphere, root endosphere and bulk soil microbiomes were different in the contrasting soil pH ranges. The strongest impact of plant species on the belowground microbiomes was in alkaline soils, suggesting a greater selective effect under alkali stress. Evaluation of soil chemical components showed that in addition to soil pH, cation exchange capacity also had a strong impact on shaping bulk soil microbial communities. This study extends our knowledge regarding the importance of pH to microbial ecology showing that root endosphere and rhizosphere microbial communities were also influenced by this soil component, and highlights the important role that plants play particularly in shaping the belowground microbiomes in alkaline soils.

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