Spatial Distribution of Trophic Groups of Amoebae Around the Root Zone of Zea Mays Mycorrhizal With Rhizophagus Intraradices Grown in Microcosms

Fitness and productivity of most terrestrial plants depend on early associations with arbuscular mycorrhizal fungi and mutualistic bacteria. Plants select most of the microbial communities cohabiting their roots and mycorrhizosphere, attracting also all types of microbial predators. Naked amoebae are among the most voracious predators inflicting significant changes in soils bacterial and fungal populations. We evaluated how roots of Zea mays with or without Rhizophagus intraradices mycorrhizosphere (AMF) influence trophic groups of amoebae, along vertical (3, 6, and 9-cm) and horizontal soil distribution (roots and free-root compartments) grown in microcosms after, 20 days. Amoebae community in Non-AMF showed a high species richness in the root zone at 3 to 6-cm depth, and at the two free-root compartment away from plants. Conversely, AMF and mycelium zones modified the amoeba community at 6 to 9-cm depth, recording higher diversity of trophic groups than unplanted soil compartments. The highest bacterivorous diversity was found at the closer compartment to AMF roots, but fungivorous amoebae was not recorded. Amoebae feeding preferences were similar in both AMF and Non-AMF microcosms in where bacterivorous amoebae were dominant, while protozoa-eating amoebae were more frequent at the mycelium compartments. Rare amoebae species were found in AMF microcosms in comparison to those recorded from Non-AMF and unplanted microcosms.

Analysis of Bacillus thuringiensis treatment impact on microflora and cellulosolytic processes in southern chernozem

When using insecticides based on B. thuringiensis in biocenoses, the issues of their influence directly on plants and soil fertility are particularly relevant. The aim of the research was to study the direction of microbiological processes in the soil after processing potato plants with liquid spore cultures of entomopathogenic B. thuringiensis 792, 800, 810, 815, 857, 888, 902, 989, 994 and 0371 strains. The nature and extent of insecticide exposure were assessed by the quantity of microorganisms in the main ecological and trophic groups. It has been shown that soil treatment with B. thuringiensis strains 792, 854 and 989 influences the intensity of southern chernozem CO2 emission most actively, by 5.7-6.0 times. The studies made it possible to establish that B. thuringiensis strains 810, 854, 888 and 902 are able to exert the most active effect on the decomposition of cellulolose, increasing its activity by 93.7; 85.6; 82.0-93.7% to control. The statistically significant relationships study of correlation dependences made it possible to conclude that the treatment of southern chernozem with strains of B. thuringiensis 792, 800, 810, 854, 888 and 0371 does not have a destructive effect on soil microbocenosis.

Changes in the microbial community structure triggered by permafrost peat thawing

An increase in permafrost temperature, accompanied by the melting and release of buried organic carbon, is one of the elements of the global warming scenario. To understand the way ecosystems respond to environmental changes, it is necessary to elucidate the factors affecting the distribution and activity of microbes in permafrost soils, which have been poorly studied so far. Meanwhile, they can have significant implications for nutrient cycling and related processes. Our research is devoted to assessing changes in the structure of the microbial community due to the melting of the palsa permafrost layer caused by the fire in 2007. The ecological-trophic groups of microorganisms of the territories changed under the influence of a natural fire in comparison with undisturbed analogs have been studied. It was revealed that the number of microorganisms in most groups on the palsa, affected by fire, is statistically significantly higher than the number of microorganisms in the undisturbed area.

Hoverflies (Syrphidae: Diptera) in areas contaminated with heavy metals (Cd, Zn, Pb)

The aim of the research was to study the diversity of hoverflies (Syrphidae: Diptera) living in areas under the influence of heavy metal emissions (Cd, Zn and Pb). Although the area of the Olkusz Ore-bearing Region (OOR), where the research was partially conducted, belongs to the contaminated regions, where a relatively high species richness of Syrphids has been noted. During the research period, a total of 1,180 syrphids, belonging to 165 species were caught, which constitutes 39.76% of all the Polish Syrphidae fauna. These species represented all the trophic groups with the dominance of zoophagous species (48.48%); however, the most numerous (quantitatively abundant) were saprophagous. Among the collected syrphids, common and numerous species, such as: E. arbustorum (LINNAEUS, 1758), E. tenax (LINNAEUS, 1758), Episyrphus balteatus (DE GEER, 1776) and S. pipiens (LINNAEUS, 1758), as well as rare species such as Callicera aenea (FABRICIUS, 1777) (NT), Chalcosyrphus piger (FABRICIUS, 1794) (DD), Epistrophe ochrostoma (ZETTERSTEDT, 1849) (VU), Orthonevra geniculata (MEIGEN, 1830) (DD), Rhingia rostrata (LINNAEUS, 1758) (DD), Sphegina sibirica STACKELBERG, 1953 (LC) and Spilomyia diophthalma (LINNAEUS, 1758) (NT), were noted. Eleven of the collected species have been included in the Polish Red List of Endangered Species. Melangyna ericarum (COLLIN, 1946) is recorded as a new one among the Polish fauna. Numerous observations did not indicate that the area covered by the study was characterised by a significantly lower species diversity compared to other sites. In fact, the samples taken were usually characterised by a relatively high biodiversity. The obtained results may suggest that anthropogenic activities, including those leading to environmental pollution with heavy metals and to a strong transformation of natural habitats, do not completely destroy biodiversity, and in some cases leave space for nature to create habitats where even rare species of organisms such as Syrphidae can develop.

QUANTITATIVE COMPOSITION THE MICROORGANISMS OF RHIZOSPHERE AGRICULTURAL PLANTS

During 2020, on the basis of stationary and temporary field experiments, which are located in the Skvуra Research Station of Organic Production of NAAS, Nosiv SDS and the Institute of Vegetable and Melon NAAS were studied quantitative composition of the soil micromycetes under different agricultural crops: winter wheat, spring barley and onion. The vegetation period in the Kyiv region was characterized by – sufficiently moist (HTC 1,7), and in Chernihiv and Kharkiv regions drought prevailed (HTC 0,6). Adverse weather conditions such as drought or waterlogging are crucial factors in changing the number of mycobiomes in the studied soils.Stationary field experiments in the selection Nosivka during the ontogenesis winter wheat characterized the greatest number pedatrophic and less number of amylolytic, cellulosolytic ecological-trophic groups. The stationary experiments field researches were also conducted in Skvyra Research Station of Organic Production. Where the rhizosphere soil under spring barley crops is characterized by a larger number of micromycetes, as well as amylolytic and cellulolytic ecological-trophic groups. Was determined the number of soil micromycetes the main ecological and trophic groups. The rhizosphere soil on the stationary field of the Institute of Vegetable and Melon NAAS during the ontogenesis of different varieties of onions characterized by high number cellulosolytic group of micromycetes, which despite the decrease in the hydrothermal coefficient increased by the end of the growing season of the culture.Therefore, the interaction between plants and micromycetes is a dynamic process in which the hydrothermal coefficient during the growing season, soil type, and the root system of agricultural plants, this influences the formation of soil mycobiome.

Predicting the sign of trophic effects: individual-based simulation versus loop analysis

Food web research needs to be predictive in order to support decisions system-based conservation. In order to increase predictability and applicability, complexity needs to be managed in such a way that we are able to provide simple and clear results. One question emerging frequently is whether certain perturbations (environmental effects or human impact) have positive or negative effects on natural ecosystems or their particular components. Yet, most of food web studies do not consider the sign of effects. Here, we study 6 versions of the Kelian River (Borneo) food web, representing six study sites along the river. For each network, we study the signs of the effects of a perturbed trophic group i on each other j groups. We compare the outcome of the relatively complicated dynamical simulation model and the relatively simple loop analysis model. We compare these results for the 6 sites and also the 14 trophic groups. Finally, we see if sign-agreement and sign-determinacy depend on certain structural features (node centrality, interaction strength). We found major differences between different modelling scenarios, with herbivore-detritivore fish behaving in the most consistent, while algae and particulate organic matter behaving in the least consistent way. We also found higher agreement between the signs of predictions for trophic groups at higher trophic levels in sites 1–3 and at lower trophic levels in site 4–6. This means that the behaviour of predators in the more natural sections of the river and that of producers at the more human-impacted sections are more consistently predicted. This suggests to be more careful with the less consistently predictable trophic groups in conservation management.