Non-parametric Multidimensional Scaling Research Articles

Assessment of parent and alkyl -PAHs in surface sediments of Iranian mangroves on the northern coast of the Persian Gulf: Spatial accumulation distribution, influence factors, and ecotoxicological risks

Spatial patterns, potential origins, and ecotoxicological risk of alkylated (APAH) –and parent –(PPAH) polycyclic aromatic hydrocarbons (PAHs) were studied in mangrove surface sediments along the northern coasts of the Persian Gulf, Iran. The mean total concentrations (ngg−1dw) ∑32PAH, ∑PPAHs and ∑APAHs in sediments were 3482 (1689–61228), 2642 (1109–4849), and 840 (478–1273), respectively. The spatial variability was similar among these PAH groups, with the highest levels occurring in Nayband National Marine Park (NNMP). Physicochemical environmental factors, such as sediment grain size, and total organic carbon (TOC) contents, are significant factors of PAH distribution. These findings suggest that PAH pollution level is moderate-to-high, supporting the current view that mangrove ecosystems are under intensive anthropogenic impacts, such as petrochemical, oil and gas loads, port activities, and urbanization. Non-parametric multidimensional scaling (NPMDS) ordination demonstrated that NNMP mangrove is the critical site exhibiting high loading of PAH pollutants. Here, for the first time in this region, Soil quality guidelines (SQGs), Toxic equivalency quotient (TEQ), Mutagenic equivalency quotient (MEQ), and composition indices comprising Mean maximum permissible concentration quotient (m-MPC-Q), and Mean effect range median quotient (m-ERM-Q) methods were used to have a comprehensive risk assessment for PAH compounds and confirmed medium-to-high ecological risks of PAHs in the study area, particularly in the western part of the Gulf, highlighting the industrial impacts on the environment.

Extracellular enzyme activity in the coastal upwelling system off Peru: a mesocosm experiment

Abstract. The Peruvian upwelling system is a highly productive ecosystem with a large oxygen minimum zone (OMZ) close to the surface. In this work, we carried out a mesocosm experiment off Callao, Peru, with the addition of water masses from the regional OMZ collected at two different sites simulating two different upwelling scenarios. Here, we focus on the pelagic remineralization of organic matter by the extracellular enzyme activity of leucine aminopeptidase (LAP) and alkaline phosphatase activity (APA). After the addition of the OMZ water, dissolved inorganic nitrogen (N) was depleted, but the standing stock of phytoplankton was relatively high, even after N depletion (mostly > 4 µg chlorophyll a L−1). During the initial phase of the experiment, APA was 0.6 nmol L−1 h−1 even though the PO43- concentration was > 0.5 µmol L−1. Initially, the dissolved organic phosphorus (DOP) decreased, coinciding with an increase in the PO43- concentration that was probably linked to the APA. The LAP activity was very high, with most of the measurements in the range of 200–800 nmol L−1 h−1. This enzyme hydrolyzes terminal amino acids from larger molecules (e.g., peptides or proteins), and these high values are probably linked to the highly productive but N-limited coastal ecosystem. Moreover, the experiment took place during a rare coastal El Niño event with higher than normal surface temperatures, which could have affected enzyme activity. Using a nonparametric multidimensional scaling analysis (NMDS) with a generalized additive model (GAM), we found that biogeochemical variables (e.g., nutrient and chlorophyll-a concentrations) and phytoplankton and bacterial communities explained up to 64 % of the variability in APA. The bacterial community best explained the variability (34 %) in LAP. The high hydrolysis rates for this enzyme suggest that pelagic N remineralization, likely driven by the bacterial community, supported the high standing stock of primary producers in the mesocosms after N depletion.

Assessing approaches to learning with nonparametric multidimensional scaling.

This article reports on a trace-based assessment of approaches to learning used by middle school aged children who interacted with NASA Mars Mission science, technology, engineering and mathematics (STEM) games in Whyville, an online game environment with 8 million registered young learners. The learning objectives of two games included awareness and knowledge of NASA missions, developing knowledge and skills of measurement and scaling, applying measurement for planetary comparisons in the solar system. Trace data from 1361 interactions were analysed with nonparametric multidimensional scaling methods, which permitted visual examination and statistical validation, and provided an example and proof of concept for the multidimensional scaling approach to analysis of time-based behavioural data from a game or simulation. Differences in approach to learning were found illustrating the potential value of the methodology to curriculum and game-based learning designers as well as other creators of online STEM content for pre-college youth. The theoretical framework of the method and analysis makes use of the Epistemic Network Analysis toolkit as a post hoc data exploration platform, and the discussion centres on issues of semantic interpretation of interaction end-states and the application of evidence centred design in post hoc analysis.

Geographical distribution and genetic diversity of Bradyrhizobium spp. isolated from Korean soybean root nodules

This study investigated the distribution and genetic diversity of the indigenous Bradyrhizobium spp. in the Korean agricultural field. A total of 254 Bradyrhizobium strains were isolated from 97 soybean samples (9 cultivars) collected in 14 regions. B. elkanii dominated in the southern regions, while B. diazoefficiens dominated in most central and northern regions. Through non-parametric multidimensional scaling (NMDS) analysis, we confirmed the possibility that environmental factors such as annual average temperature and soybean cultivars might affect the distribution of Bradyrhizobium spp. in some regions. The DNA fingerprint using repetitive DNA sequences showed the genetic diversity among the Bradyrhizobium strains isolated from the different regions. Clustering the strains based on the genetic diversity indicated that Bradyrhizobium spp. grouped into different clusters depending on geographic location. This study suggests that the Korean indigenous Bradyrhizobium spp. distribute differently according to the geographical feature, and the high genetic diversity of each strain attribute to the geographic location.

Repetitive extragenic palindromic and enterobacterial repetitive intergenic consensus sequence‐based typing of Shiga toxin‐producing Escherichia coli from bovine samples

AbstractThe strain typing of Shiga toxin‐producing Escherichia coli (STEC) is challenging due to its high genetic variability. In the present study, two polymerase chain reaction (PCR)‐based typing methods—repetitive extragenic palindromic sequences PCR (REP‐PCR) and enterobacterial repetitive intergenic consensus sequences PCR (ERIC‐PCR)—are evaluated for their efficacy in differentiating the strains. The present study used 100 strains of STEC isolated from bovine meat, bovine feces, and swabs from the chopping boards. The REP‐PCR profiles showed 21 different banding patterns, whereas ERIC‐PCR profiles obtained 18 patterns among the tested strains. The dendrogram prepared by the neighbor‐joining method formed eight and seven clusters for REP and ERIC‐PCR, respectively. The discriminatory indices for the typing methods were 87.83 and 83.03% for REP and ERIC‐PCR, respectively. Thus, the clusters based on REP and ERIC‐PCR fingerprints were unambiguous and thus could be useful for phylogenetic clustering and epidemiological surveillance. The nonparametric multidimensional scaling plots showed more than 75 and 60% similarities within populations of different REP and ERIC clusters, respectively, regarding its source of isolation, serogroup, and distribution virulence markers. The REP and the ERIC sequences are good molecular markers that offer rapid, cost‐effective, and easy molecular typing for STEC strains.

Silvopastoral systems as an alternative for conservation of dung beetles (Coleoptera: Scarabaeinae) in a cattle landscape in Caucasia Colombia

Silvopastoral systems (SPS) represent an alternative to the environmental impact and biodiversity decline caused by extensive livestock practices. We evaluate the transformation of a conventional pasture parcel into a SPS, and how it alters the diversity of dung beetles, fundamental organisms in these ecosystems. Transects with pitfall traps, baited with excrement were established in SPS, pasture, and forest ecosystems. Differences in the structure of communities were compared through Whittaker curves, the incidence of functional groups, and non-parametric multidimensional scaling. The completeness of the sampling was estimated and the magnitude of change in qD diversity of the SPS concerning pasture and forest ecosystem was calculated for each season. A total of 7446 beetles belonging to twelve genera, fifteen species, and seven morphospecies were collected. The SPS was the environment with the greatest diversity of qD and functional groups after the forest ecosystem. It was more diverse than pasture, 30 % to 50 % richer in species and 10 % to 50 % more diverse in 1D and 2D. It is concluded that the conversion of the conventional pastures to SPS led to changes in the composition and structure of the beetle community, making the SPS a more diverse environment than the pasture in all seasons including the dry one, when conditions are the most adverse. These results suggest that the implementation of SPS is an important measure to preserve and increase the diversity of forest dung beetles in the livestock areas of the country.

Distribution of Polychlorinated Naphthalenes in Sediment From Industrialized Coastal Waters of Korea With the Optimized Cleanup and GC-MS/MS Methods

Limited studies have been conducted on polychlorinated naphthalenes (PCNs) in the coastal environment worldwide. In this study, analytical methods were optimized for 18 PCN congeners in sediment using a multi-layer silica gel column and a gas chromatograph coupled to tandem mass spectrometry (GC-MS/MS). The optimized analytical methods of PCNs were employed for sediment samples from heavily industrialized bays of Korea to assess the occurrence, contamination, potential sources, and ecotoxicological concerns. PCNs were detected in all sediment samples, indicating ubiquitous contamination in industrialized coastal regions of Korea. Total concentrations and toxic equivalents (TEQs) of PCNs ranged from 0.99 to 21,500 (mean: 568) pg/g dry weight and from 1.72 × 10–5 to 18.8 (mean: 0.52) pg TEQ/g dry weight, respectively, which were within the ranges reported by other studies. A clear decreasing gradient was observed for the sedimentary PCNs from inner to outer parts of the bays, streams, and rivers. This result indicates that industrial activities are primary sources of PCNs. The highest PCN concentrations were observed in sediment close to non-ferrous and petrochemical industries, indicating potential sources. CNs 73 and 52 were predominant congeners of PCNs in all sediment samples. Diagnostic ratios and non-parametric multidimensional scaling analysis showed that the potential primary sources of PCNs are thermal-related emissions and the use of PCB technical mixtures. Although a few sediment samples exceeded the sediment quality guidelines of TEQs, the cumulative risks by dioxin-like contaminants may be caused for almost all coastal zones surveyed. This is the first report on PCNs in sediment from Korean coastal waters.

Diversification of the financial education needs of the entrepreneurial ecosystem: a multidimensional scaling analysis applied to data from a financial intelligence platform

The objective of this research is to analyze the financial education needs of the central region of the country through Non-Parametric Multidimensional Scaling (NMDS), Shannon's diversity index and Simpson's dominance index, applied to a database from of a financial intelligence technological platform to identify the similarity of financial needs among users and their financial preferences. The results obtained show similarity between the data, which indicates that there is a lack of financial knowledge in the entrepreneurial ecosystem and, therefore, a high death rate of SMEs and uninformed financial decisions based on errors of interpretation of the information.

Розподіл голих амеб у ґрунтах степової зони України

As a result of the study, in the steppe zone of Ukraine (Odessa, Mykolaiv, Kirovohrad region), 12 species of naked amoebas were identified, which according to the modern Eukaryot system belong to three molecular clusters Tubulinea Smirnov et al., 2005, Discosea Cavalier-Smith, 2004., Discoba Simpson and Hampl et al., 2009. This species Vahlkampfia sp. (1), Vahlkampfia sp. (2), Deuteramoeba mycophaga Page, 1988, Saccamoeba stagnicola Page, 1974, Vexillifera sp., Vannella sp. Ripellaplatypodia Smirnov, Nassonova, Chao et Cavalier-Smith, 2007, Cochliopodium sp. (1), Mayorella sp., Thecamoeba striata Penard, 1890, Stenamoeba stenopodia (Page, 1969) Smirnov et al., 2007, Acanthamoeba sp. (1). In the studied steppe soils, the most common were Vahlkampfia sp. (2), S. stenopodia, Vahlkampfia sp. (1), Vexillifera sp., Cochliopodium sp. (1); the least common – R. platypodia, D. mycophaga, T. striata, Mayorella sp. As a result of the cluster analysis, it was found that the largest share of common species is observed between Mykolaiv and Kirovograd regions (0.71) and Odessa and Kirovograd regions (0.53); the smallest is between the Odessa and Mykolaiv regions (0.43). According to the results of cluster analysis, the faunistic complexes of soil species of amoebae of the steppe region of Ukraine are united into two clusters: one of them being complexes characteristic of the Odessa region, and the other complexes of the Mykolaiv and Kirovograd regions. According to the results of nonparametric multidimensional scaling, it is established that the species complex of soil amoebae in the Kirovograd and Mykolaiv regions is determined by the increased soil temperature and acidity, compared to the Odessa region. As for moisture, this factor has little effect on the species complexes amoebae steppe region of Ukraine.

Effects of resource manipulation on nematode community structure and metabolic footprints in an arable soil across time and depth

Summary In an arable field the herbivore and detritivore soil food chains were manipulated by the following treatments: maize as crop, amendment with maize litter and bare soil, representing labile rhizodeposits, recalcitrant plant debris and soil organic matter as major resource, respectively. Samples from top soil, rooted zone and root-free zone were collected in two consecutive years. The impact of these differences in resource availability and quality on the nematode community composition, Maturity Index (MI), diversity () and metabolic footprints was assessed. Plant feeders were fostered by the presence of maize and fungal feeders by litter amendment. Correspondingly, non-parametric multidimensional scaling showed that nematode community structure was most different between plant and litter plots, while bare soil was nested in-between. This indicates that resource depletion under bare soil did not result in distinctly different nematode assemblages. The MI was low and similar across treatments and depths, reflecting soil disturbance by arable management. Nematode diversity was highest under the crop in the second year, which mirrors the general positive impact of plants on belowground processes. However, the composite footprint showed that the removal of plants from the system had an overall low impact on the metabolic response of the nematode community. Taken together, this indicates a considerable resilience of the soil food web to the disruption of both the root and detrital carbon channel over at least two vegetation periods.

A Multivariate Approach to the Selection and Validation of Reference Conditions in KwaZulu-Natal Rivers, South Africa

The use of reference conditions is essential to the monitoring and management of aquatic ecosystems. We examined existing and potential reference sites through historical data, maps and field data collected from river sites in KwaZulu-Natal (KZN), South Africa. In our study, we applied nine criteria that best reflect the characteristics of South African rivers on 24 a priori selected reference sites. These nine criteria comprised of catchment conditions (flow modification and natural landscape) and site-specific attributes (water quality, human disturbance, river channel, water abstraction, riparian vegetation, riparian zone modification and instream habitat quality). The a priori selected reference sites were subjected to validation using multivariate methods such as analysis of similarities (ANOSIM), similarity percentages (SIMPER) and non-parametric multidimensional scaling (MDS) based on the macroinvertebrate fauna by applying a SASS5 threshold considered to be an indicator of undisturbed sites in South African rivers. We identified differences in the macroinvertebrate assemblages of the reference conditions for each river group based on their ecoregions, geomorphology and seasonal variations. Ecoregions and river geomorphology were better in the grouping of sites with similar reference conditions than the seasons. Our findings indicated that all of the selected sites could be considered as valid reference sites; however, caution should be taken in applying this method to lowland rivers because of their noticeable seasonal variability and habitat instability which tend to alter their reference states. We recommend that a type-specific reference condition be developed for lowland rivers. Also, statistical validation of reference conditions should be a continuous process in river biomonitoring.

Seaweeds through time: Morphological and ecological analysis of Proterozoic and early Paleozoic benthic macroalgae

Benthic marine macroalgae or seaweeds are key ecological players in oceans today and have been since the Proterozoic. To date, however, morphological and evolutionary patterns for Precambrian macroalgae have been documented only in rather broad terms. To refine our understanding in this critical interval, we updated a dataset of Proterozoic to early Paleozoic noncalcified macroalgal fossils preserved as macroscopic carbonaceous compressions. The data were analyzed using non-parametric multidimensional scaling (NMDS) and functional-form group (FFG) approaches, in order to characterize morphological and ecological evolutionary patterns of these macroalgae. At the broadest scale, the results show progressive increases in thallus size, morphospace range, and aspects of ecological complexity such as canopy heights, surface area/volume ratios, and functional-form groups through time. These trends, however, are not always monotonous. In particular, significant increases in Proterozoic macroalgal morphological diversity and maximum size appear to have occurred in the Neoproterozoic (Tonian and Ediacaran periods, respectively). Analysis of Ediacaran macroalgal assemblages shows that macroalgae broadly follow the Ediacara-like fossil assemblages, with a significant drop in most studied metrics in the terminal Ediacaran stage (~550–539 Ma). The latter event occurs during the Kotlinian crisis experienced by Ediacara-type macro-organisms, highlighting the possibility that this extinction event during the Ediacaran-Cambrian transition affected both macroalgae and Ediacara-type macro-organisms. Our analysis also confirms an Ordovician increase in the morphological and ecological diversity of macroalgae.

Changes in Foot Skin Microbiome of Patients with Diabetes Mellitus Using High-Throughput 16S rRNA Gene Sequencing: A Case Control Study from a Single Center.

BackgroundWorldwide, the treatment of complications associated with type 2 diabetes mellitus, including diabetic foot ulcer (DFU), results in an economic burden for patients and healthcare systems. This study aimed to use high-throughput 16S rRNA gene sequencing to investigate the changes in foot skin microbiome of patients with diabetes mellitus from a single center in China.Material/MethodsFifty-two participants were divided into 4 study groups: healthy controls (n=13); patients with short-term diabetes (<2 years; n=13); patients with intermediate-term diabetes (5–8 years; n=13); and patients with long-term diabetes (>10 years; n=13). Swabs were analyzed from the intact skin of the foot arch using high-throughput 16S ribosomal RNA sequencing.ResultsMicrobiome phylogenic diversity varied significantly between the study groups (whole tree, P<0.01; Chao1, P<0.01), but were similar within the same group. The findings were supported by non-parametric multidimensional scaling (stress=0.12) and principal component analysis (principal component 1, 8.38%; principal component 2, 5.28%). In patients with diabetes mellitus, the dominant skin microbial phyla were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes.ConclusionsHigh-throughput 16S rRNA gene sequencing showed dynamic changes in the skin microbiome from the foot during the progression of diabetes mellitus. These findings support the importance of understanding the role of the skin microbiota in the pathogenesis of DFU.

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.

Chronic ecotoxicity of ciprofloxacin exposure on taxonomic diversity of a meiobenthic nematode community in microcosm experiments

A laboratory bioassay was performed to assess the ecotoxicity of ciprofloxacin on a meiobenthic nematodes community from Bizerte lagoon (NE Tunisia). Four ciprofloxacin doses [D1 (50 µg/g), D2 (100 µg/g), D3 (200 µg/g), and D4 (500 µg/g)] were applied to the substrate, and responses were studied after one month. Discernible differences were observed between control assemblages and those populating ciprofloxacin treated substrates. All univariate indices were affected significantly compared to those in the control microcosm with increasing antibiotic concentration. The non-parametric Multi-Dimensional Scaling based on species abundances (MDS) showed significant separation of the control microcosm from the antibiotic-treated populations. The nematode species responses to the fluoroquinolone treatments varied: Odontophora villoti was reduced at all concentrations of ciprofloxacin and was considered “sensitive,” whereas Metoncholaimus pristiurus was affected by moderate concentrations; its abundance increased with the highest dose D4 and was described as “opportunistic.” Paramonohystera pilosa, whose abundance increased with antibiotic doses appeared “resistant.”

Evidence for pre-climacteric activation of AOX transcription during cold-induced conditioning to ripen in European pear (Pyrus communis L.).

European pears (Pyrus communis L.) require a range of cold-temperature exposure to induce ethylene biosynthesis and fruit ripening. Physiological and hormonal responses to cold temperature storage in pear have been well characterized, but the molecular underpinnings of these phenomena remain unclear. An established low-temperature conditioning model was used to induce ripening of 'D'Anjou' and 'Bartlett' pear cultivars and quantify the expression of key genes representing ripening-related metabolic pathways in comparison to non-conditioned fruit. Physiological indicators of pear ripening were recorded, and fruit peel tissue sampled in parallel, during the cold-conditioning and ripening time-course experiment to correlate gene expression to ontogeny. Two complementary approaches, Nonparametric Multi-Dimensional Scaling and efficiency-corrected 2-(ΔΔCt), were used to identify genes exhibiting the most variability in expression. Interestingly, the enhanced alternative oxidase (AOX) transcript abundance at the pre-climacteric stage in 'Bartlett' and 'D'Anjou' at the peak of the conditioning treatments suggests that AOX may play a key and a novel role in the achievement of ripening competency. There were indications that cold-sensing and signaling elements from ABA and auxin pathways modulate the S1-S2 ethylene transition in European pears, and that the S1-S2 ethylene biosynthesis transition is more pronounced in 'Bartlett' as compared to 'D'Anjou' pear. This information has implications in preventing post-harvest losses of this important crop.

Resource partitioning among sympatric elasmobranchs in the central-western Mediterranean continental shelf

Knowledge of the mechanisms that allow coexistence among sympatric species is fundamental to understand ecosystem functioning. Resource partitioning among seven elasmobranchs inhabiting the Sardinian continental shelf (40°07′N, 9°00′E): Dasyatis pastinaca; Raja asterias; R. brachyura; R. clavata; R. miraletus; R. polystigma and Scyliorhinus canicula, was investigated through stomach content analysis. Data from 1680 samples collected between 2005 and 2014, in 26–200 m depth, were analysed with respect to population, sex, season (winter and summer) and size groups. Species living in shallower waters (characterized by a narrower bathymetric range) had the most specialized diets. All species appeared to be mesopredators, feeding mainly on Crustacea, Actinopterygii, Mollusca and Polychaeta. Despite shared common morphological features, from the high ecological diversity of prey items, we hypothesized the presence of different predatory behavior among the species studied: some species were able to feed on endobenthic and/or epibenthic organisms, while others had made limited movements in the water column. Non-parametric Multi-Dimensional Scaling analysis highlighted the presence of five predator groups, confirming strong resource partitioning, as also demonstrated by low levels of interspecific niche overlap. The observed variations in feeding habits could be ascribed only to size and not to sex or season. Generally, diet changed from small Crustacean prey, to larger prey, like Actinopterygii and Mollusca. Some species became more generalist during development, others restricted their prey range. Shifts in feeding habits affected species’ roles in the food web, with different species occupying different functional trophic groups over the course of their life cycles.

Variations in the Botanical Diversity of Forbs–Bunchgrass Steppes of Eastern Mongolia over an 11-Year Period (2008–2018)

The dynamics of the botanical diversity of plain forbs–bunchgrass steppes is analyzed for the period of 2008–2018 based on materials from the biomonitoring of plant cover at the Tumentsogt experimental station (Eastern Mongolia) as part of the scientific program of an integrated Russian–Mongolian biological expedition. Eight permanent test plots of 100 m2 were laid along the transect on the plain between hills in the northeastern part of the experimental station. We analyzed the correlation between the main parameters of the plant communities (the species composition, richness, and saturation; the height and abundance of species; and the density of grass stands) with the meteorological conditions (the heat supply and the amount and distribution of precipitation during the growing period). A combined analysis of phytocenotic and climatic data was performed with nonparametric multidimensional scaling of indirect ordination. Ecotopic fluctuations caused by changes in the amount and regime of precipitation in different years, as well as by the dynamics of the temperature regime, were studied. The species saturation of communities was maximal in years with low ombrothermic indices and lowest in years with high indices. The floristic composition of communities of three–feather-grass steppes includes a flora-cenotic core composed of 23 permanent perennial steppe and forest–steppe species, which provides a relative stability of ecosystems under changing environmental conditions. The dynamics of steppe ecosystems of the East Mongolian steppes is phytocyclic.

Metagenomic profiling of fresh water lakes at different altitudes in Pakistan

Freshwater lakes play a crucial role in sustainability of ecosystem in the favour of communities flourishing around it. In this study, differential metagenomic evaluation of three freshwater ecosystems in Pakistan was carried out. These included Lakes Keenjhar, Rawal and Saif-ul-Muluk situated at the altitudes 21, 527, 3224 m respectively. Former two lakes serve as water reservoirs for three major cities of Pakistan, while the high-altitude Lake Saif-ul-Muluk is located in a pristine environment at the meeting point of Himalayan and Karakoram ranges. Next generation sequencing (NGS) of metagenomic DNA of microbial communities was carried out using surface water samples from these lakes by Illumina Hi-Seq 2500 sequencing technology. Bioinformatics analysis identified Proteobacteria as the most dominant phylum (58–79%) followed by Planctomycetes (34%), Cyanobacteria (12%) and Bacteroidetes (15%). Lake Saif-ul-Muluk contained highest abundance of bacterial genera including Vibrio, Bordetella, Pseudomonas, Burkholderia and Escherichia; while Microcystis were found to be abundant in Lakes Keenjhar and Rawal. Non-parametric multi-dimensional scaling (NMDS) principle component analysis on genus level revealed that these ecosystems were divergent from each other and from metagenomes of lakes in the Americas. Characterization of virulence factors and antibiotics resistant genes in metagenomic contigs were also identified. Chemical profiling of Lakes Keenjhar and Rawal showed higher concentration of phosphorus which indicated eutrophication in these lakes might be due to Microcystis infestation.

Unexpected consequences of bombing. Community level response of epiphytic diatoms to environmental stress in a saline bomb crater pond area.

The spatial response of epiphytic diatom communities to environmental stress was studied in a moderately saline wetland area located in the plain of Danube-Tisza Interfluve, Hungary. The area is characterised by World War II bomb crater ponds and can be regarded as an excellent ecological model system where the dispersion of species is slightly limited by distance. To study the effect of environmental variables on the communities, canonical correspondence analysis was applied. Salinity, pH, total suspended solids, total phosphorous and depth proved to be significant environmental drivers in this analysis. The ecological status of the ponds was assessed with Ziemann’s halobity index, as the trophity-depending metric cannot be applied to these habitats (due to the naturally high phosphorus content). Ponds in “good” ecological status significantly differed from those appertaining to water quality category of “not-good” ecological status considering characteristic of natural astatic soda pans (e.g. salinity, pH, ammonium, total phosphorous concentration, nitrogen:phosphorous ratio and turbidity). The differences between epiphytic diatom communities inhabiting the ponds were detected using non-parametric multidimensional scaling. The samples formed three groups according to the types of ponds (“transparent”, “transitional” and “turbid”) based on the width of the macrophyte belt around them. Indicator species related to the ecological status of the ponds and diatom communities contributing to the separation of groups of ponds were identified. One of the indicator species differed from species already described. Light and scanning electron microscopy features and phylogenetic analyses based on three genes (18S and 28S rRNA genes, rbcL) proved that it was a new species of Nitzschia genus, closely related to Nitzschia frustulum and Nitzschia inconspicua. Therefore, description of a new species, Nitzschia reskoi Ács, Duleba, C.E.Wetzel & Ector is proposed. We concluded that the increasing abundance of Nitzschia reskoi was a signal of the degradation of the intermittent saline wetlands.