Decrease In Species Diversity Research Articles

The Impact of Age and Pathogens Type on the Gut Microbiota in Infants with Diarrhea in Dalian, China.

Objective Diarrhea in infants is a serious gastrointestinal dysfunction characterized by vomiting and watery bowel movements. Without proper treatment, infants will develop a dangerous electrolyte imbalance. Diarrhea is accompanied by intestinal dysbiosis. This study compared the gut microbiota between healthy infants and diarrheic infants. It also investigated the effects of age and pathogen type on the gut microbiota of infants with diarrhea, providing data for the proper treatment for diarrhea in infants. Materials and Methods DNA was collected from the fecal samples of 42 Chinese infants with diarrhea and 37 healthy infants. The healthy infants and infants with diarrhea were divided into four age groups: 0–120, 120–180, 180–270, and 270–365 days. Using PCR and 16S rRNA high-throughput sequencing, the diarrhea-causing pathogens in these infants were identified and then categorized into four groups: Salmonella infection, Staphylococcus aureus infection, combined Salmonella and Staphylococcus aureus infection, and others (neither Salmonella nor Staphylococcus aureus). Results The species diversity of gut microbiota in diarrheic infants was significantly reduced compared with that in healthy infants. Infants with diarrhea had a lower abundance of Lactobacillus spp. and Bacillus spp. (P < 0.001) and a significant richness of Klebsiella spp. and Enterobacter spp. (P < 0.001). Similar gut microbiota patterns were found in diarrheic infants in all four age groups. However, different pathogenic infections have significant effects on the gut microbiota of diarrheic infants. For instance, the relative abundance of Klebsiella spp. and Streptococcus spp. was significantly increased (P < 0.001) in infants infected with Staphylococcus aureus; meanwhile, the richness of bacteria such as Enterobacter spp. was significantly increased in the Salmonella infection group (P < 0.001). Conclusion The microbiota in infants with diarrhea has changed significantly, characterized by decreased species diversity and abundance of beneficial bacteria and significant increase in the proportion of conditional pathogens. Meanwhile, the gut microbiota of infants with diarrhea at different ages was similar, but different pathogenic infections affect the gut microbiota characteristics. Therefore, early identification of changes in gut microbiota in infants with diarrhea and the adoption of appropriate pathogen type-specific interventions may effectively alleviate the disease and reduce adverse reactions.

Uncovering the microbiota in renal cell carcinoma tissue using 16S rRNA gene sequencing.

Increasing evidence indicates an important role of microbiota in cancer development and progression, while little is known about the correlation between microbiota and renal cell carcinoma (RCC). Thus, we performed this study to profile the intratumoral microbiota possibly associated with RCC. Paired RCC and adjacent normal tissue samples were collected from 24 patients with RCC. V3-V4 variable region of microbial 16S rRNA gene was sequenced using Illumina MiSeq. Sequencing reads were processed using QIIME. Differentially abundant bacterial taxa between groups were identified by LEfSe, and their potential functions were inferred by PICRUSt. Decreased species diversity was presented in RCC tissues (Simpson index, P = 0.0340), and the composition of the bacterial community in RCC tissues was significantly distinct from that in normal tissues (unweighted UniFrac distance, P = 0.026; weighted UniFrac distance, P = 0.017). Compared with normal tissues, 25 taxa increased and 47 reduced taxa were identified in RCC tissues. Among these taxa, the class Chloroplast (AUC = 0.91, P < 0.0001) and the order Streptophyta (AUC = 0.89, P < 0.0001) showed high indication accuracy to discriminate RCC tissues from normal tissues. Furthermore, nine altered pathways were identified in RCC tissues to reveal the potential microbial function. Our results have uncovered the presence of distinct microbiota in RCC and adjacent normal tissues and provided a better understanding of the possible role of the intratumoral microbiota in RCC. Further studies are required to confirm our results and determine the real correlation between microbiota and RCC.

Intraspecific variability in fluctuating environments: mechanisms of impact on species diversity.

Recent studies have found considerable trait variations within species. The effect of such intraspecific trait variability (ITV) on the stability, coexistence, and diversity of ecological communities received considerable attention and in many models it was shown to impede coexistence and decrease species diversity. Here we present a numerical study of the effect of genetically inherited ITV on species persistence and diversity in a temporally fluctuating environment. Two mechanisms are identified. First, ITV buffers populations against varying environmental conditions (portfolio effect) and reduces variation in abundances. Second, the interplay between ITV and environmental variations tends to increase the mean fitness of diverse populations. The first mechanism promotes persistence and tends to increase species richness, while the second reduces the chance of a rare species population (which is usually homogeneous) to invade, thus decreasing species richness. We show that for large communities the portfolio effect is dominant, leading to ITV promoting species persistence and richness.

Dynamics of Modern Vegetation for Pasture Use in the Northwestern Pre-Caspian Region

This article presents the results of long-term studies of the process of desertification (degradation) of the dry lands of the northwestern Pre-Caspian region. Modern vegetation is considered to occur as a result of pasture overload with livestock. The authors consider this process to be “unification,” which leads to a decrease in species diversity in communities and, as a consequence, to uniformity of the vegetation cover. The complexity of the soil and vegetation cover characteristic of the Pre-Caspian region disappears, and a sequential change occurs in indigenous plant communities by a group of short-term derivatives. Quantitative assessment of the desertification process includes (classes) the stages of desertification, the criteria for pastoral digression, and the corresponding indicators, plant communities. They determine the ecological–dynamic series of plant communities, which reveal the mechanism of the degradation process. The study showed that the vegetation of the youngest New Caspian terrace within the northwestern Pre-Caspian region is characterized by high susceptibility to this process.

Benthic foraminifera and brachiopods from a marine cave in Spain: environmental significance

Sediment samples from a marine cave in the Murcia region (eastern Spain) were analysed for grain size, total benthic foraminiferaand dead brachiopoda to obtain environmental information through physical and ecological data in order to understandthe benthic communities of cave environments and their ecological significance. A total of 100 foraminiferal and 7 brachiopodspecies were classified, highlighting the first occurrence in the western Mediterranean of Gwynia capsula (Jeffreys, 1859). Statistical analysis applied to foraminiferal data allowed the identification of three assemblages characterised by decreasing species diversity along the cave. This corresponded to a similar separation recognisable through changes in brachiopod species abundance and well-correlated with cave morphology. The relative abundance of epifaunal clinging-attached foraminifera as well as the rate of cave and sciaphilic/coralligenous Brachiopoda, thought to be representative of the degree of separation from marine conditions,were found to be highly correlated, increasing towards the inner cave. Our hypothesis was that despite the different lifestyles ofthese two groups, the strict correlation of environmental factors (i.e. light, nutrients, sediment texture, water parameters) changingalong the length of the cave determines a comprehensive environmental gradient, causing an increase in environmental stress that has similar effects on the different taxonomic groups.

Effect of land-use types on edaphic properties and plant species diversity in Mediterranean agroecosystem.

Land-use intensification, contrary to sustainable land management, has an impact on the healthiness of the environmental agroecosystem. To assess the environmental implications in abandoned land, olive groves and maize crops, the most sensitive and reliable edaphic indicators were measured to estimate plant species diversity and potentially toxic elements in soil, among different types of land-use. Species diversity presents a decrease in maize crops and olive groves compared to abandoned land. The families with the greatest species diversity were Poaceae, Asteraceae and Fabaceae in each land-use. From the results of the canonical correspondence analysis among species, sampling sites and selected environmental variables, a clear separation between species and sampling sites belonging to different types of land-use was found, presenting strong correlation with specific edaphic parameters (pH, Soil Organic Matter, Silt, Electrical Conductivity, Total Nitrogen, , P, K, Zn and Cu). Species diversity was reduced in maize crops due to anthropogenic interventions such as the excessive use of nitrogen and phosphate fertilizers and herbicides. Despite the fact that the lowest richness of plant species was found in olive groves, non-removal of crop residue preserves soil organic matter. In 7.4% of soil samples in olive groves, concentrations were over 100 mg kg−1 denoting polluted soils, while the potentially toxic concentrations of bioavailable copper fraction ( probably lead to a decrease of species diversity. Future researches should therefore focus on the accumulation of toxic elements in agricultural land to preserve species diversity and a healthy environment.

Antibiotic-induced alterations and repopulation dynamics of yellowtail kingfish microbiota

BackgroundThe use of antibiotics in aquaculture is a common infection treatment and is increasing in some sectors and jurisdictions. While antibiotic treatment can negatively shift gut bacterial communities, recovery and examination of these communities in fish of commercial importance is not well documented. Examining the impacts of antibiotics on farmed fish microbiota is fundamental for improving our understanding and management of healthy farmed fish. This work assessed yellowtail kingfish (Seriola lalandi) skin and gut bacterial communities after an oral antibiotic combination therapy in poor performing fish that displayed signs of enteritis over an 18-day period. In an attempt to promote improved bacterial re-establishment after antibiotic treatment, faecal microbiota transplantation (FMT) was also administered via gavage or in the surrounding seawater, and its affect was evaluated over 15 days post-delivery.ResultsAntibiotic treatment greatly perturbed the global gut bacterial communities of poor-performing fish – an effect that lasted for up to 18 days post treatment. This perturbation was marked by a significant decrease in species diversity and evenness, as well as a concomitant increase in particular taxa like an uncultured Mycoplasmataceae sp., which persisted and dominated antibiotic-treated fish for the entire 18-day period. The skin-associated bacterial communities were also perturbed by the antibiotic treatment, notably within the first 3 days; however, this was unlike the gut, as skin microbiota appeared to shift towards a more ‘normal’ (though disparate) state after 5 days post antibiotic treatment. FMT was only able to modulate the impacts of antibiotics in some individuals for a short time period, as the magnitude of change varied substantially between individuals. Some fish maintained certain transplanted gut taxa (i.e. present in the FMT inoculum; namely various Aliivibrio related ASVs) at Day 2 post FMT, although these were lost by Day 8 post FMT.ConclusionAs we observed notable, prolonged perturbations induced by antibiotics on the gut bacterial assemblages, further work is required to better understand the processes/dynamics of their re-establishment following antibiotic exposure. In this regard, procedures like FMT represent a novel approach for promoting improved microbial recovery, although their efficacy and the factors that support their success requires further investigation.

Unravelling the effects of multiple stressors on diatom and macroinvertebrate communities in European river basins using structural and functional approaches

Rivers suffer from more severe decreases in species diversity compared to other aquatic and terrestrial ecosystems due to a variety of pressures related to human activities. Species provide different roles in the functioning of the ecosystem, and their loss may reduce the capacity of the ecosystems to respond to multiple stressors. The effects on diversity will differ based on the type, combination and severity of stressors, as well as on the characteristics of the community composition and tolerance. Multiple trait-based approaches (MTBAs) can help to unravel the effects of multiple stressors on communities, providing a mechanistic interpretation, and, thus, complementing traditional biodiversity assessments using community structure. We studied the relationships between diversity indexes and trait composition of macroinvertebrate and diatom communities, as well as environmental variables that described the hydrological and geomorphological alterations and toxic pollution (pesticides and pharmaceuticals) of three different European river basins: the Adige, the Sava, and the Evrotas. These river basins can be considered representative cases of different situations in European freshwater systems. Hydrological variables were the main drivers determining the community structure and function in the rivers, for both diatoms and macroinvertebrates. For diatom communities, pharmaceutical active compound (PhAC) toxic units were also identified as a very important driver of diversity changes, explaining up to 57% of the variance in taxonomic richness. For macroinvertebrates, river geomorphology was an important driver of structural changes, particularly affecting Plecoptera richness. In addition, PhAC and pesticide toxic units were also identified as stressors for macroinvertebrate communities. MTBA provided a detailed picture of the effects of the stressors on the communities and confirmed the importance of hydrological variables in shaping the functional attributes of the communities.

Moderate to Severe Ulcerative Colitis Results in Differential Metabolism of Cranberry Polyphenols by the Colon Microbiome Ex Vivo

Abstract Objectives The microbiome plays a major role in polyphenol metabolism, producing metabolites that are bioavailable and potentially more bioactive than the polyphenol compounds from which they are derived. A consequence of ulcerative colitis (UC) is a ‘dysbiotic’ microbiome characterized by decreased species diversity, which may impact an individual's capability to metabolize polyphenols into bioavailable metabolites. The objective was to compare the microbial metabolism of cranberry polyphenols between fecal donors that were healthy or had moderate to severe UC to determine if dysbiosis effects polyphenol metabolism. Methods Fecal samples were donated by volunteers with or without moderate to severe UC (n = 9). Fecal samples were cultured anaerobically within 2 hours of defecation in the presence of A and B type proanthocyanidins, flavonols and anthocyanins extracted from cranberry powder. Aliquots were taken at 5 different time points over a 48-hour period and the resulting polyphenol metabolites were quantified via LC-ESI-MS/MS using SRM and authentic standards. 16S rRNA metagenomics analysis was also utilized to assess changes in the composition of the fecal microbiota. Results After 6 hours, healthy individuals produced 2.50, 20.1 and 5.25-fold higher (P &amp;lt; 0.05) concentrations of 3-(3-hydroxyphenyl)propionic acid, 3,4-dihydroxyphenylacetic acid and 3’,4’-dihydroxyphenyl-gamma-valerolactone, respectively. Healthy individuals continued to have significantly higher concentrations of these metabolites over the 48-hour period. UC microbiomes did not produce 3-hydroxyphenylacetic until after 48 hours, suggesting that the microbiome of those with UC may have significantly lower de-hydroxylase activity. Healthy microbiomes contained higher (P &amp;lt; 0.05) proportions of Ruminococcaceae, which could explain their ability to produce higher concentrations of cranberry polyphenol metabolites. Conclusions The microbiome of individuals with UC produces significantly lower cranberry polyphenol metabolites than healthy microbiomes. These results suggest that efficiency of polyphenol metabolism is dependent on health status of the colon and polyphenols could be potential biomarkers of colon health. Funding Sources Ocean Spray Cranberries, Inc, Middleborough, MA.

Research on innovative marine environmental conservation with no environmental impact using marine bio-cement

According to a growing body of research from scientists all over the world, the Earth is heading towards a global catastrophe. Polar ice caps are melting due to rising global temperatures and there have been many consequences for our oceans. The impact of human activity on the oceans has led to growing acidity of the water, as well as rising sea levels. Pollution and physical damage from human activities such as dredging and shipping have hit marine life hard, reducing animal and plant populations and decreasing species diversity. This reduction in key marine components such as the seaweed beds has a massive impact on other species, causing ripple effects that can be felt by humans. Providing food, shelter and breeding grounds for fish, squid, crustaceans and many other organisms, a decrease in the seaweed forests directly correlates to a reduction in sea life in the area, which affects the marine environment as a whole as well threatening the local fishing industry. Scientists have been trying to tackle this damage to the seaweed beds by developing ways in which to re-seed areas of the seabed. A variety of approaches have been taken to growing new seaweed to restore these habitats, but many of these methods are expensive and labour intensive. Associate Professor Masataka Kusube, from the Department of Applied Chemistry and Biochemistry, National Institute Technology at Wakayama College in Japan, is working with a number of industrial partners, including Mitsui Chemicals Inc. to produce large scale marine microbe cultures by pilot test facility and KYC Machine Industry Co., Ltd. to generate large scale marine bio-cement production, Kusube and his team have developed an innovative material dubbed 'marine bio-cement' to support the growth of eelgrass in the waters surrounding Japan.

The more we do, the less we gain? Balancing effort and efficacy in managing the Solidago gigantea invasion

AbstractDeveloping invasive plant management strategies is an important task in modern ecology, conservation biology and land management. Solidago gigantea is considered a problematic invader in Europe and Asia, where it forms dominant stands that can decrease species diversity. There is, therefore, an urgent need for effective management to reduce S. gigantea infestations and their negative impacts. We examined the efficacy of multiple approaches to S. gigantea management in Hungary. In our study, we evaluated the effect of several long‐term management techniques such as grazing, mowing and periodic flooding on the invader's density as well as native community diversity. In addition, we investigated the short‐ and long‐term effects of mowing combined with other treatment options, to estimate the influence of increased management intensity. Our results indicate that all tested management techniques had negative impacts on S. gigantea density. Short‐term mowing did not appear to improve species diversity in the resident community; however, all long‐term options improved species diversity. Moreover, combining treatments with mowing varied in its effectiveness; mowing once increased the efficacy of flooding, but decreased the efficacy of grazing, while mowing twice decreased efficacy of flooding. We suspect this is due to the increased intensity of disturbance, which does not allow for the natural recovery of communities, and after management ceases, invasion is able to re‐occur. Our results indicate that for effective management, we need to combine management options which act via different mechanisms, leading to cumulative positive effects on the resident community when applied at moderate levels.

A heatwave increases turnover and regional dominance in microbenthic metacommunities

While the effect of the global biodiversity crisis on local species loss is still debated, there is empirical evidence for major changes in local biodiversity attributed to increased species turnover. In communities exposed to a climate stressor, species turnover can lead to increased dominance of well-adapted species and consequently to an overall decline in species diversity. Despite the known importance of species turnover for community dynamics and functioning, experimental results on the connection between biodiversity loss and species turnover are scarce. We still do not fully understand which specific factors increase the rate of change in species composition, especially when considering natural compared to artificially lab assembled communities. In the present study, we experimentally tested whether a heatwave and dispersal increased species turnover and decreased species diversity in natural benthic diatom communities with different initial species compositions. We found that on the local scale, dispersal had overall positive effects on species richness while the relationship between exposure to the heatwave, species turnover, and diversity depended on initial community composition. However, on the regional (i.e. metacommunity) scale, exposure to the heatwave and dispersal both increased turnover and decreased Shannon diversity by almost 50%. Turnover in these metacommunities was not caused by a loss of species, but rather by a change in dominance patterns leading to homogenization, and consequently decreased diversity. Our study shows that climate change can destabilize community composition and degrade species diversity, but still after ca. 15 generations does not decrease the number of species in the community, demonstrating that the response of species diversity and richness to changing conditions can be fundamentally decoupled on ecological time scales.

The Estimation of the Initial Stage of Succession of Green-pine Trees Windfall in the Eastern Moscow Suburbs

The paper is devoted to the study of entomocomplex of stem pests, the number and biology of its dominant species and the ecological structure of the soil mesofauna of the two differing in composition and growing conditions, areas of wind pine forests-green insects. The main causes of windfalls, which are unfavorable soil and soil conditions and the defeat of trees by the root sponge, are established. The degree of participation of different types of feed substrate in the dynamics of the number of stem pests in the lesion is estimated. In addition to the windfall of trees, stem pests are the adjacent one, decreasing the resistance of pine in the walls of the forest, overmature trees or trees weakened by anthropogenic, standing trees, the trunks of which are damaged by windfall to a lesser extent than the remaining standing part of inboard of broken trunks. We identified eight species of entomophagous parasitic on the grubs of Longhorn beetles and jewel beetles. It is noted that the population of ground beetles, in windswept areas studied, is characterized by a decrease in species diversity, a decrease in the number of moisture-loving species typical of pine forests of the Eastern Moscow region, a change in the spectrum of life forms in the direction of reducing litter species and increasing the proportion of litter-soil.

COMPARATIVE ANALYSIS OF THE NEMATODIAN FAUNA AND ITS SEASONAL DYNAMICS OF AGRICULTURAL PLANTS OF FOOTHILL REGIONS OF THE TASHKENT OASIS

The article presents data on the species and quantitative composition of nematode communities of soil layers of agrocenoses and natural ecosystems of the foothill regions of the Tashkent oasis of the Republic of Uzbekistan. As a result of studies, it was revealed that 54 species are widespread in the soil layers of wheat fields, 45 species in tomato fields and 65 species of nematodes in natural ecosystems. In the seasonal dynamics of the number of nematodes, spring and autumn peaks are observed, when the number of nematode individuals is several times higher compared to the summer and winter periods. Autumn temperature drop and a slight increase in soil moisture contribute to a new increase in species diversity and number of phytonematodes. A decrease in species diversity and number of phytonematodes in winter is associated with a decrease in temperature and the absence of a power source. The vertical distribution of soil nematodes and their accumulation in a particular soil layer, first of all, depends on the presence of the root system of plants, the optimum temperature and humidity of the soil and air. Various ecological groups of nematodes and their individual species do not react equally to changes in the conditions of existence, as the dynamics of para-isobionts were maximal in the spring, while in eusaprobionts, there was a small group that included only 4 species (4.1%) of nematodes. The species composition of devisaprbionts is more diverse in the spring and autumn. Phytohelminths are represented by 40 species (40.8%), in the dynamics of their species composition there are no sharp fluctuations that were observed in other ecological groups. The maximum number (27) of species is confined to the spring period. The difference in species diversity and the number of phytonematodes in different plants, soil layers and seasons was determined, which is associated with vegetation, changes in humidity and temperature in different soil layers.

Assessment of the impact of railway traffic on the state of plant communities

The article reflects the results of studies on the impact of railway traffic on plant communities. The anthropogenic impact on the environment is complex. Many factors affect the species diversity of the flora near railways in different ways. The accumulation of Cd, Zn, Pb, Cr in plants ofPimpinella saxifragaL.,Hypericum perforatumL.,Trifolium mediumL was revealed. The anthropogenic stress leads to disruption of naturally formed ecosystems, which manifests in a decrease in species diversity, density and biological productivity. As a result of the anthropogenic impact adventitious plants appear, the share of which is 11% of the flora. Research in this area contributes to a deeper understanding of the processes of anthropogenic transformation of floristic complexes and should become the basis for environmental monitoring of disturbed habitats.

PECULIARITIES OF SEASONAL CHANGES IN THE TAXONOMIC STRUCTURE AND NUMBER OF TURUN BEETLE (COLEOPTERA, CARABIDAE) HERPETOBIA IN URBAN CENOSES OF KHARKIV

A total of 99 species from 35 genera of Carabidae have been registered in the urban cenoses of Kharkiv. The eudominants were Harpalus affinis Schrank, 1781, H. griseus Panzer, 1797, H. rufipes De Geer, 1774. The dominants included 17 species: Notiophilus biguttatus Fabricius, 1779, N. germinyi Fauvel, 1863, Сarabus nemoralis O.Müller, 1764, Broscus cephalotes Linnaeus, 1758, Asaphidion flavipes Linnaeus, 1761, Poecilus versicolor Sturm, 1824, Pterostichus melanarius Illiger, 1798, Calathus ambiguus Paykull, 1790, C. fuscipes Goeze, 1777, Amara apricaria Paykull, 1790, A. bifrons Gyllenhal, 1810, Harpalus distinguendus Duftschmid, 1812, H. modestus Dejean, 1829, H. smaragdinus Duftschmid, 1812, H. tardus Panzer, 1797, H. xanthopus winkleri Schauberger, 1923, Panagaeus bipustulatus Fabricius, 1775. Other species are registered as rare. The total number of species was higher at household plots (46) and in the city outskirts (41 species). Fewer species are registered in cities parks, the Forest Park, and the plots of the center (33–35 species). The maximum number of species (for all cenoses) is observed in May (from 45 to 56 species depending on the year). In June and the first half of July, the species diversity decreases (to 40–42), and in August, 14– 39 species were registered. In September, a total of 25–27 species were recorded, and in the first half of October only 4–14 species. The maximum dynamic density was registered at the household plots and in the city outskirts (0.13–0.73 specimen / 1 trap-day), the minimum density of carabids was observed in the Forest Park and the plantings in the center of the city (0.03–0.06 specimen / 1 trap-day). The increase in the number of carabids began from the second half of April to mid-May, with a peak at the end of the latter month or in the first decade of June. The decline of carabids population density was registered in late June – early July, mainly in the parks. In the household plots, the plots of the center and in the city outskirts, the maximal density was registered in July – August, mainly due to increased activity of species of the genus Harpalus. In September, the density of carabids decreased sharply, and from the last decade of September until the first half of October, single individuals were observed. When comparing the seasonal changes of the sex index and the dynamic density of the dominant species (for example, C. nemoralis), the maximum population density was observed 10–20 days earlier than the maximal level of sex index.

Ecological and Faunistic Structure of Ground Beetle Population (Coleoptera, Carabidae) of Forest Belts in The Tambov Region (Russia)

The article presents the analysis of ground beetle population in forest belts of different types. The ecological structure of ground beetle complexes of forest belts is determined by soil and moisture conditions. Differences in the diversity of ground beetle populations depending on a complex of soil and plant conditions and the nature of anthropogenic impact are found. The increase in steppe formation and xerophytism conditions in forest belts leads to a decrease in species diversity of the genera Carabus, Poecilus, Pterostichus, Calathus, Amara and Harpalus.

Zooplankton community structure before and after Mnemiopsis leidyi arrival

Abstract In the present study, the temporal dynamics of zooplankton community of the North West Adriatic Sea (coastal area of Emilia-Romagna region, Italy) was monitored over 12 years. The distribution and abundance of zooplankton species were investigated in relation to physical and biological parameters (temperature, salinity, dissolved oxygen and chlorophyll-a). Since November 2015 the non-indigenous copepod Pseudodiaptomus marinus, Sato, 1913 has been observed in the study area. During summer 2016, the American comb jelly Mnemiopsis leidyi, A. Agassiz, 1865 was recorded there for the first time and its presence was continuously monitored since that time (weekly observations from August 2016 to December 2017). Our study confirmed that the environmental conditions of the study area were suitable for M. leidyi growth. In addition, due to the combined effects of temperature, salinity and food availability M. leidyi was able to survive during winter months. Particular attention was then given to zooplankton abundance and community changes between two time periods: before and after M. leidyi arrival. Statistical analysis revealed significant differences in zooplankton abundance between the two time periods and a decrease in species diversity and evenness was observed during summer 2016.

The influence of fluids on the species composition and preservation of microfossils in biogenic carbonate sediments by hydrothermal cluster “Pobeda” (Mid-Atlantic ridge)

The species composition, distribution and preservation of carbonate shells of nanno and microfossils of biogenic bottom sediments within the hydrothermal cluster Pobeda (1707.451708.7 n) were studied on the basis of materials obtained in flight No. 37 of NIS Professor Logachev in the Russian exploration area (Mid-Atlantic ridge). Physical-chemical parameters and the total carbonate content of sediments were measured, their changes in column sections were revealed. For complexes of coccoliths studied precipitation is attributed to the top (acme) biostratigraphic zone of Emiliania huxleyi. It is established that within the zone of hydrothermal activity (ore cluster Pobeda) the total number of microorganisms decreases and their species diversity decreases, as a rule, in the lower part of the columns. Down the column section also decreases the Eh, pH and carbonate precipitation. These changes are explained by the influence of diffuse hydrothermal fluids.

Legacy effects of soil homogenization on tallgrass prairie restoration: toward resolved understanding of the relationship between soil heterogeneity and plant species diversity

Within plant communities, niche‐based species sorting can occur among distinct soil patches (microsites), increasing coexistence and diversity. Microsite edges (microedges) may also offer additional niche space. Therefore, in recently abandoned croplands, which often have uniform soils caused by a legacy of tillage (soil homogenization), the plant species diversity of future restoration efforts may be reduced. We conducted an experiment during the early establishment phase (3 years) of a tallgrass prairie restoration on former cropland to determine if soil homogenization decreases species diversity and alters community composition, and if microedges offer additional niche space. Heterogeneous plots with sand‐ or woodchip‐enriched patches were compared to plots made up of the same components, but distributed homogeneously, and pits and mounds were compared to flat topsoil. Homogenization decreased diversity in flat topsoil plots relative to pit plots and increased diversity in woodchip plots. In both cases, the treatments with the lowest canopy cover and greatest plant density had the greatest diversity. Sand and topographic homogenization decreased diversity, but when a drought occurred in year two, the effect was suppressed in the sand treatment and magnified in the pit plots. Microedges had properties unique from adjacent patches. Overall, variability in heterogeneity–diversity relationships was affected by interactions with plant growth patterns and environmental conditions. Our results indicate that while the addition of contrasting soil microsites has the potential to promote increased diversity in grassland restoration on former cropland, the patch components and design must be optimized to achieve this management goal.