Changes In Relative Abundance Research Articles

Legacy and novel perfluoroalkyl and polyfluoroalkyl substances in industrial wastewater and the receiving river water: Temporal changes in relative abundances of regulated compounds and alternatives

Concentrations of 28 novel and legacy perfluoroalkyl and polyfluoroalkyl substances (PFASs) in wastewater from 77 industrial plants in the largest industrial complex in Korea were determined. The industrial plants were of eight types (advanced electronic, battery, chemical, general electronic, glass and ceramic, metal, polymer, and textile). PFAS concentrations in river water receiving the wastewater were determined to assess the impact of wastewater from the industrial complex. Only 19 and nine target PFASs were detected in untreated industrial wastewater and river water, respectively. Novel PFASs such as F53B (6:2 chlorinated polyfluoroalkyl ether sulfonate) were not detected. The mean PFASs concentration in industrial wastewater treatment plant effluent was 5.18 µg/L. The mean total PFASs concentration was highest in advanced electronic plant effluent, second highest in general electronic plant effluent, and lowest in battery and chemical plant effluents. Perfluorohexane sulfonate was the dominant homolog, being detected in effluent from plants of all classes and contributing 96% of total discharged PFASs by mass. Perfluorooctane sulfonate (included in the Stockholm Convention) use has decreased markedly since previous studies. Perfluorooctane sulfonate has largely been replaced by PFASs with fewer than seven carbon atoms. A similar change was found for river water receiving industrial wastewater.

Signatures of landscape and captivity in the gut microbiota of Southern Hairy-nosed Wombats (Lasiorhinus latifrons)

BackgroundHerbivorous mammals co-opt microbes to derive energy and nutrients from diets that are recalcitrant to host enzymes. Recent research has found that captive management—an important conservation tool for many species—can alter the gut microbiota of mammals. Such changes could negatively impact the ability of herbivorous mammals to derive energy from their native diets, and ultimately reduce host fitness. To date, nothing is known of how captivity influences the gut microbiota of the Southern Hairy-nosed Wombat (SHNW), a large herbivorous marsupial that inhabits South Australia. Here, using 16S rRNA gene sequencing, we characterized the faecal microbiota of SHNWs in captivity and from three wild populations, two from degraded habitats and one from an intact native grass habitat.ResultsWe found that captive SHNWs had gut microbiota that were compositionally different and less diverse compared to wild SHNWs. There were major differences in gut microbiota community membership between captive and wild animals, both in statistically significant changes in relative abundance of microbes, and in the presence/absence of microbes. We also observed differences in microbial composition between wild populations, with the largest difference associated with native vs. degraded habitat.ConclusionsThese results suggest that captivity has a major impact on the gut microbiota of SHNWs, and that different wild populations harbour distinct microbial compositions. Such findings warrant further work to determine what impacts these changes have on the fitness of SHNWs, and whether they could be manipulated to improve future management of the species.

Effect of Sodium Lauryl Sulfate (SLS) Applied as a Patch on Human Skin Physiology and Its Microbiota

In this study, we assessed the change in skin microbiota composition, relative abundance, and diversity with skin physiology disruption induced by SLS patch. Healthy women declaring to have a reactive skin were submitted to a 0.5% aqueous sodium lauryl sulfate solution application under occlusive patch condition for 24 h. Skin properties were characterized by tewametry, corneometry, and colorimetry and bacterial diversity was assessed by 16S rRNA sequencing. Analysis before and one day after SLS patch removal revealed an increase of skin redness and a decrease of stratum corneum hydration and skin barrier function. The relative abundance of taxa containing potential pathogens increase (Firmicutes: Staphylococcaceae; Proteobacteria: Enterobacteriaceae, Pantoea) while some of the most occurring Actinobacteria with valuable skin protection and repair capacities decreased (Micrococcus, Kocuria, and Corynebacterium). We observed an impaired skin barrier function and dehydration induced by SLS patch disturb the subtle balance of skin microbiota towards skin bacterial community dysbiosis. This study provides new insights on the skin bacterial composition and skin physiology simultaneously impaired by a SLS patch.

Impacts of invasive cane toads on an Endangered marsupial predator and its prey

Recent research has revealed that impacts of some invasive species are chronic. Invasive cane toads Rhinella marina have apparently caused rapid and severe population-level declines of the Endangered northern quoll Dasyurus hallucatus across tropical Australia; however, more targeted, quantitative impact data are needed to disentangle this from other threats such as fire regimes, disease, feral cats and dingos. Moreover, repeatable counts before, during, after and long after toad invasion are needed in order to determine if short-term impacts are chronic vs. transitory. We used game cameras to monitor 2 quoll populations and their prey over a 5 yr period spanning the invasion of the toxic cane toads in 2 gorges in northwestern Australia. We predicted severe declines in quolls with the toad invasion, and predatory release of 2 prey species of quolls, a rodent and a smaller marsupial. Quolls declined quickly upon arrival of toads, becoming undetectable in one gorge and barely detectable in the other. Identification of individuals via unique spot patterns confirmed that the declines in detection rates were due to changes in relative abundance rather than decreases in activity. Despite quoll declines we found no evidence of mesopredator release; small mammals generally declined as toads arrived. Our research confirmed rapid population-level declines of quolls, and possibly smaller mammals, associated with arrival of invasive cane toads. Importantly, our surveys provide a baseline for future surveys to determine whether these short-term impacts are chronic or transitory, and whether recovery requires assistance from managers.

The rectal mucosal but not fecal microbiota detects subclinical ulcerative colitis

ABSTRACT Ulcerative colitis (UC), a subtype of inflammatory bowel disease, is characterized by repetitive remission and relapse. Gut microbiome is critically involved in pathogenesis of UC. The shifts in microbiome profile during disease remission remain under-investigated. Recent studies revealed that UC pathogenesis is likely to originate in the mucosal barrier. Therefore, we investigated the effectiveness of mucosal tissue microbiomes to differentiate patients with subclinical UC from healthy individuals. The microbiomes of cecal and rectal biopsies and feces were characterized from 13 healthy individuals and 45 patients with subclinical UC. Total genomic DNA was extracted from the samples, and their microbial communities determined using next-generation sequencing. We found that changes in relative abundance of subclinical UC were marked by a decrease in Proteobacteria and an increase in Bacteroidetes phyla in microbiome derived from rectal tissues but not cecal tissue nor feces. Only in the microbiome of rectal tissue had significantly higher community richness and evenness in subclinical UC patients than controls. Twenty-seven operational taxonomic units were enriched in subclinical UC cohort with majority of the taxa from the Firmicutes phylum. Inference of putative microbial functional pathways from rectal biopsy microbiome suggested a differential increase in interleukin-17 signaling and T-helper cell differentiation pathways. Rectal biopsy tissue was suggested to be more suitable than fecal samples for microbiome assays to distinguish patients with subclinical UC from healthy adults. Assessment of the rectal biopsy microbiome may offer clinical insight into UC disease progression and predict relapse of the diseases.

Detecção e ocupação de uma espécie de passeriforme em ambiente urbano

The modification of natural areas to meet the needs of human beings is called urbanization. Its effects on bird groups have been extensively studied, and mainly address changes in relative abundance and demographic aspects. Here we wished to determine the probabilities of detection and occupancy of the Great Kiskadee Pitangus sulphuratus in urban environments. We selected 10 sites within the urban area of ​​the city of Santa Helena, western Paraná state, southern Brazil, to conduct 5-minute point counts and used occupancy modelling and logistic regression to determine the aforementioned parameters. The probability of detecting the species is suggested to halve as a function of time, while its occupancy probability alone was not related to the levels of afforestation or noise pollution; the number of houses around point counts showed a positive influence on their detection. When we analyzed the probability with the variables together and their interactions, our results suggest that Great Kiskadee is well adapted to urban environments.

1281. Longitudinal and Spatial Variation in the Human Microbiome in a Phase 2a Clinical Study of Gepotidacin in Adult Females with Uncomplicated Urinary Tract Infection

BackgroundGepotidacin (GSK2140944) is a first in class novel oral triazaacenaphthylene bacterial topoisomerase inhibitor. In this study, we evaluated the potential impact of orally administered gepotidacin on the human microbiome, across three body-sites and at three specific time-points, as an exploratory endpoint in a Phase 2a clinical trial for the treatment of uncomplicated Urinary Tract Infection (uUTI) (ClinicalTrials.gov: NCT03568942).MethodsThrough DNA sequencing of the 16S rRNA variable region 4, we analyzed samples collected with consent from study subjects from the gastrointestinal tract or GIT (stool), pharyngeal cavity (saliva swabs) and vagina (vaginal swabs). Samples were taken at three time points which were pre-dosing (Day 1), end of dosing (Day 5) and follow-up visit (Day 28 ±3 days). A total of 156 samples were collected and 141 samples passed quality control criteria for DNA sequence analyses. Using a rigorous computational work-flow, changes in microbiome diversity and relative abundances of microbial species were quantified.ResultsTime series analyses showed that microbiota alpha diversity dropped, relative to pre-dose, by the end of gepotidacin dosing but trended a return trajectory to original pre-dose levels by the follow-up visit, for all body sites (Figure). However, the character and extent of the microbiota changes varied by location. The relative ordering from least to greatest changes in microbiota diversity of body sites is vaginal, pharyngeal and GIT. We found no statistically significant occurrences of pathogen related taxa, such as Clostridioides or Enterobacterales spp., at the final timepoints.ConclusionSince gepotidacin is both orally dosed and elimination includes the biliary route, it was predicted to affect the GIT microbiome, however changes in the distal pharyngeal and vaginal microbiota were also observed. Gepotidacin alteration of the endogenous microbial community appears to be temporary and reversible as microbiota diversity rebounded to near pre-dosing status within a period of several weeks. Our study illustrates how microbiome analyses in antibiotic clinical studies can quantify patterns of microbiota disruption and recovery.DisclosuresAndrea Nuzzo, PHD, GlaxoSmithKline (Employee) Stephanie Van Horn, B.Sc., GlaxoSmithKline (Employee) Christopher Traini, PHD, GlaxoSmithKline (Employee) Caroline R. Perry, PhD, GlaxoSmithKline (Employee) Etienne Dumont, MD, GlaxoSmithKline (Employee) Nicole Scangarella-Oman, MS, GlaxoSmithKline plc. (Employee, Shareholder) David Gardiner, MD, GlaxoSmithKline (Employee) James R. Brown, PhD, GlaxoSmithKline (Employee)

Species abundance fluctuations over 31 years are associated with plant–soil feedback in a species‐rich mountain meadow

Abstract Increasing evidence suggest that plant–soil interactions play an essential role in plant community assembly processes. Empirical investigations show that plant species abundance in the field is often related to plant–soil biota interactions; however, the direction of these relations have yielded inconsistent results. We combined unique 31‐year long field data on species abundances from a species‐rich mountain meadow with single time point plant–soil feedback greenhouse experiments of 24 co‐occurring plant species. We tested whether these relations were dynamic in time, whether coupled increases and decreases in abundance between years were related to plant–soil feedback and whether these changes were underlain by years in which manuring was applied. The prevailingly negative relationship between plant–soil feedback and plant relative abundance in the field was significantly time‐dependent, which may reconcile the contrasting results in literature. Furthermore, significantly coupled oscillations appeared between species relative abundance changes and plant–soil feedback, which were likely moderated by years in which manuring was applied. Our results are consistent with the notion that the more abundant species are stabilised by negative plant–soil feedback, and the less abundant species co‐vary with the fluctuations of these more competitive species. Synthesis. Our results project plant–soil feedback as an important regulatory mechanism in plant communities, operating in conjunction with species' competitive ability and soil nutrient availability. We suggest that negative feedback is particularly prominent in more abundant plant species that profit from more readily available soil nutrients than less abundant species with positive feedback. Negative plant–soil feedback may thus prevent more abundant plant species from out‐competing less abundant plant species, facilitating stable species co‐existence.

Monitoring and Surveillance of Aerial Mycobiota of Rice Paddy through DNA Metabarcoding and qPCR.

The airborne mycobiota has been understudied in comparison with the mycobiota present in other agricultural environments. Traditional, culture-based methods allow the study of a small fraction of the organisms present in the atmosphere, thus missing important information. In this study, the aerial mycobiota in a rice paddy has been examined during the cropping season (from June to September 2016) using qPCRs for two important rice pathogens (Pyricularia oryzae and Bipolaris oryzae) and by using DNA metabarcoding of the fungal ITS region. The metabarcoding results demonstrated a higher alpha diversity (Shannon–Wiener diversity index H′ and total number of observed species) at the beginning of the trial (June), suggesting a higher level of community complexity, compared with the end of the season. The main taxa identified by HTS analysis showed a shift in their relative abundance that drove the cluster separation as a function of time and temperature. The most abundant OTUs corresponded to genera such as Cladosporium, Alternaria, Myrothecium, or Pyricularia. Changes in the mycobiota composition were clearly dependent on the average air temperature with a potential impact on disease development in rice. In parallel, oligotyping analysis was performed to obtain a sub-OTU identification which revealed the presence of several oligotypes of Pyricularia and Bipolaris with relative abundance changing during monitoring.

Simulated Winter Incubation of Soil With Swine Manure Differentially Affects Multiple Antimicrobial Resistance Elements.

Gastrointestinal bacteria that harbor antibiotic resistance genes (ARG) become enriched with antibiotic use. Livestock manure application to cropland for soil fertility presents a concern that ARG and bacteria may proliferate and be transported in the environment. In the United States, manure applications typically occur during autumn with slow mineralization until spring planting season. A laboratory soil incubation study was conducted mimicking autumn swine manure application to soils with concentrations of selected ARG monitored during simulated 120-day winter incubation with multiple freeze-thaw events. Additionally, the effects of two soil moistures [10 and 30% water holding capacity (WHC)] and two manure treatments [raw versus hydrated lime alkaline stabilization (HLAS)] were assessed. Fourteen tetracycline resistance genes were evaluated; tet(D), tet(G), and tet(L) were detected in background soil while swine manure contained tet(A), tet(B), tet(C), tet(G), tet(M), tet(O), tet(Q), and tet(X). By day 120, the manure-borne tet(M) and tet(O) were still detected while tet(C), tet(D), tet(L), and tet(X) genes were detected less frequently. Other tet resistance genes were detected rarely, if at all. The sum of unique tet resistance genes among all treatments decreased during the incubation from an average of 8.9 to 3.8 unique tet resistance genes. Four resistance elements, intI1, blactx–m–32, sul(I), erm(B), and 16s rRNA genes were measured using quantitative PCR. ARG abundances relative to 16S abundance were initially greater in the raw manure compared to background soil (−1.53 to −3.92 log abundance in manure; −4.02 to <−6.7 log abundance in soil). In the mixed manure/soil, relative abundance of the four resistance elements decreased (0.87 to 1.94 log abundance) during the incubation largely because 16S rRNA genes increased by 1.21 log abundance. Throughout the incubation, the abundance of intI1, blactx–m–32, sul(I), and erm(B) per gram in soil amended with HLAS-treated manure was lower than in soil amended with raw manure. Under low initial soil moisture conditions, HLAS treatment reduced the abundance of intI1 and resulted in loss of blactx–m–32, sul(I), and erm(B)] compared to other treatment-moisture combinations. Although one might expect antibiotic resistance to be relatively unchanged after simulated winter manure application to soil, a variety of changes in diversity and relative abundance can be expected.

Effect of an 8-week Exercise Training on Gut Microbiota in Physically Inactive Older Women.

Exercise can alter the composition of gut microbiota. However, studies examining the effects of exercise on gut microbiota in the elderly are lacking. This study aims to investigate whether an 8-week exercise training affect gut microbiota in physically inactive elderly women. Fourteen women were randomly assigned to either exercise group or control group. Repeated-measures analysis of variance was used to reveal changes in gut microbiota. Alpha diversity did not change significantly. A tendency to form 2 clusters was observed for operational taxonomic units (OTU) after intervention. At phylum, class, and order levels, a significant difference was observed between two groups for Fusobacteria (F=5.257, P=0.045), Betaproteobacteria (F=5.149, P=0.047), and Bifidobacteriales (F=7.624, P=0.020). A significant interaction was observed between two groups for Actinobacteria (F=8.434, P=0.016). At family and genus levels, a significant main effect of groups was observed in Bifidobacteriaceae (F=7.624, P=0.020), Bifidobacterium (F=7.404, P=0.022), and Gemmiger (F=5.881, P=0.036). These findings indicate that an 8-week exercise training may induce partial changes in relative abundance and OTU clustering of gut microbiota in physically inactive elderly women. Also, exercise may increase the abundance of bacteria associated with anti-inflammation such as Verrucomicrobia, reduce the abundance of bacteria associated with pro-inflammation such as Proteobacteria.

Corrigendum: Using DNA metabarcoding for assessing chironomid diversity and community change in mosquito controlled temporary wetlands. MBMG 2: e21060. https://doi.org/10.3897/mbmg.2.21060

Chironomids have been proposed as important indicators for monitoring freshwater ecosystems, however, morphological determination is very challenging. In this study, we investigated the effectiveness of metabarcoding for chironomid diversity assessment and tested the retrieved chironomid operational taxonomic units (OTUs) for possible changes in relative abundance and species diversity in relation to mosquito control actions in four temporary wetlands. The biocide Bacillus thuringiensis var. israelensis (Bti) is widely applied for mosquito control in temporary wetlands of the German Upper Rhine Valley. Even though Bti is considered environmentally friendly, several studies have shown non-target effects on chironomids, a key food resource in wetland ecosystems Three of the studied wetlands were, for the first year after 20 years of Bti treatment, partly left Bti-untreated in a split field design, and one wetland has never been treated with Bti. Our metabarcoding approach detected 54 chironomid OTUs across all study sites, of which 70% could be identified to species level comparisons against the BOLD database. We showed that metabarcoding increased chironomid species determination by 70%. However, we found only minor significant effects of Bti on the chironomid community composition. Subsequent studies will have to address if and how the chironomid community composition might change in the now Bti-untreated temporary wetlands to assess effects of Bti.

Comparative Analysis of Milk Triglycerides Profile between Jaffarabadi Buffalo and Holstein Friesian Cow.

Milk lipids are known for a variety of biological functions, however; little is known about compositional variation across breeds, especially for Jaffarabadi buffalo, an indigenous Indian breed. Systematic profiling of extracted milk lipids was performed by mass spectrometry across summer and winter in Holstein Friesian cow and Jaffarabadi buffalo. Extensive MS/MS spectral analysis for the identification (ID) of probable lipid species using software followed by manual verification and grading of each assigned lipid species enabled ID based on (a) parent ion, (b) head group, and (c) partial/full acyl characteristic ions for comparative profiling of triacylglycerols between the breeds. Additionally, new triacylglycerol species with short-chain fatty acids were reported by manual interpretation of MS/MS spectra and comparison with curated repositories. Collectively, 1093 triacylglycerol species belonging to 141 unique sum compositions between the replicates of both the animal groups were identified. Relative quantitation at sum composition level followed by statistical analyses revealed changes in relative abundances of triacylglycerol species due to breed, season, and interaction effect of the two. Significant changes in triacylglycerols were observed between breeds (81%) and seasons (59%). When the interaction effect is statistically significant, a higher number of triacylglycerols species in Jaffarabadi has lesser seasonal variation than Holstein Friesian.

Effects of Excess Manganese on the Xylem Sap Protein Profile of Tomato (Solanum lycopersicum) as Revealed by Shotgun Proteomic Analysis.

Metal toxicity is a common problem in crop species worldwide. Some metals are naturally toxic, whereas others such as manganese (Mn) are essential micro-nutrients for plant growth but can become toxic when in excess. Changes in the composition of the xylem sap, which is the main pathway for ion transport within the plant, is therefore vital to understanding the plant’s response(s) to metal toxicity. In this study we have assessed the effects of exposure of tomato roots to excess Mn on the protein profile of the xylem sap, using a shotgun proteomics approach. Plants were grown in nutrient solution using 4.6 and 300 µM MnCl2 as control and excess Mn treatments, respectively. This approach yielded 668 proteins reliably identified and quantified. Excess Mn caused statistically significant (at p ≤ 0.05) and biologically relevant changes in relative abundance (≥2-fold increases or ≥50% decreases) in 322 proteins, with 82% of them predicted to be secretory using three different prediction tools, with more decreasing than increasing (181 and 82, respectively), suggesting that this metal stress causes an overall deactivation of metabolic pathways. Processes most affected by excess Mn were in the oxido-reductase, polysaccharide and protein metabolism classes. Excess Mn induced changes in hydrolases and peroxidases involved in cell wall degradation and lignin formation, respectively, consistent with the existence of alterations in the cell wall. Protein turnover was also affected, as indicated by the decrease in proteolytic enzymes and protein synthesis-related proteins. Excess Mn modified the redox environment of the xylem sap, with changes in the abundance of oxido-reductase and defense protein classes indicating a stress scenario. Finally, results indicate that excess Mn decreased the amounts of proteins associated with several signaling pathways, including fasciclin-like arabinogalactan-proteins and lipids, as well as proteases, which may be involved in the release of signaling peptides and protein maturation. The comparison of the proteins changing in abundance in xylem sap and roots indicate the existence of tissue-specific and systemic responses to excess Mn. Data are available via ProteomeXchange with identifier PXD021973.

Differentiating and Quantifying Gas-Phase Conformational Isomers Using Coulomb Explosion Imaging.

Conformational isomerism plays a crucial role in defining the physical and chemical properties and biological activity of molecules ranging from simple organic compounds to complex biopolymers. However, it is often a significant challenge to differentiate and separate these isomers experimentally as they can easily interconvert due to their low rotational energy barrier. Here, we use the momentum correlation of fragment ions produced after inner-shell photoionization to distinguish conformational isomers of 1,2-dibromoethane (C2H4Br2). We demonstrate that the three-body breakup channel, C2H4+ + Br+ + Br+, contains signatures of both sequential and concerted breakup, which are decoupled to distinguish the geometries of two conformational isomers and to quantify their relative abundance. The sensitivity of our method to quantify these yields is established by measuring the relative abundance change with sample temperature, which agrees well with calculations. Our study paves the way for using Coulomb explosion imaging to track subtle molecular structural changes.

Dietary adaptation to high starch involves increased relative abundance of sucrase-isomaltase and its mRNA in nestling house sparrows.

Dietary flexibility in digestive enzyme activity is widespread in vertebrates but mechanisms are poorly understood. When laboratory rats are switched to a higher carbohydrate diet, the activities of the apical intestinal α-glucosidases (AGs) increase within 6-12 h, mainly by rapid increase in enzyme transcription, followed by rapid translation and translocation to the intestine's apical, brush-border membrane (BBM). We performed the first unified study of the overall process in birds, relying on activity, proteomic, and transcriptomic data from the same animals. Our avian model was nestling house sparrows (Passer domesticus), which switch naturally from a low-starch insect diet to a higher starch seed diet and in whom the protein sucrase-isomaltase (SI) is responsible for all maltase and sucrase intestinal activities. Twenty-four hours after the switch to a high-starch diet, SI activity was increased but not at 12 h post diet switch. SI was the only hydrolase increased in the BBM, and its relative abundance and activity were positively correlated. Twenty-four hours after a reverse switch back to the lower starch diet, SI activity was decreased but not at 12 h post diet switch. Parallel changes in SI mRNA relative abundance were associated with the changes in SI activity in both diet-switch experiments, but our data also revealed an apparent diurnal rhythm in SI mRNA. This is the first demonstration that birds may rely on rapid increase in abundance of SI and its mRNA when adjusting to high-starch diet. Although the mechanisms underlying dietary induction of intestinal enzymes seem similar in nestling house sparrows and laboratory rodents, the time course for modulation in nestlings seemed half as fast compared with laboratory rodents. Before undertaking modulation, an opportunistic forager facing limited resources might rely on more extensive or prolonged environmental sampling, because the redesign of the intestine's hydrolytic capacity shortly after just one or a few meals of a new substrate might be a costly mistake.

Ecotoxicological assessment of commercial boron nitride nanotubes toward Xenopus laevis tadpoles and host-associated gut microbiota

Despite the growing interest for boron nitride nanotubes (BNNT) due to their unique properties, data on the evaluation of the environmental risk potential of this emerging engineered nanomaterial are currently lacking. Therefore, the ecotoxicity of a commercial form of BNNT (containing tubes, hexagonal-boron nitride, and boron) was assessed in vivo toward larvae of the amphibian Xenopus laevis. Following the exposure, multiple endpoints were measured in the tadpoles as well as in bacterial communities associated to the host gut. Exposure to BNNT led to boron accumulation in host tissues and was not associated to genotoxic effects. However, the growth of the tadpoles increased due to BNNT exposure. This parameter was associated to remodeling of gut microbiome, benefiting to taxa from the phylum Bacteroidetes. Changes in relative abundance of this phylum were positively correlated to larval growth. The obtained results support the finding that BNNT are biocompatible as indicated by the absence of toxic effect from the tested nanomaterials. In addition, byproducts, especially free boron present in the tested product, were overall beneficial for the metabolism of the tadpoles.

A 700-year multiproxy reconstruction on the Argentinian Pampas inferred from the sediments of Laguna Blanca Grande

The Pampean region is a crucial area to obtain sensitive paleoclimatic lacustrine archives due to the presence of shallow environments in a territory non impacted by humans until the last centuries. In this study, we provide a paleoecological reconstruction for the last ca. 700 years based on a multiproxy lacustrine record from Laguna Blanca Grande, in Olavarría (Buenos Aires, Argentina). Our inferences, which were based on sedimentary properties, diatom, cladoceran and ostracod assemblages, offered interesting information about hydroclimatic variability and nutrient increase. Changes in relative abundances on diatoms, specifically on Aulacoseira granulata and Aulacoseira granulata var. angustissima and fragilariods, were used to infer shifts in nutrient conditions. The remainder proxies together indicated small lake level changes. Reconstructed hydroclimatic conditions in Laguna Blanca Grande are consistent with previous paleoecological inferences indicating a humid phase around ca. AD 1450 and progressive drier conditions ca. AD 1530–1900. A flood gate construction and an increase of nutrients in the lake revealed a higher human pressure due to population increase and land-use changes during the last century. Further studies on taxonomy and autecology of microcrustaceans are needed to effectively unlock the information contained in biological proxies from Sudamerican records.

Differential effects of fertilisers on pollination and parasitoid interaction networks

Grassland fertilisation drives non-random plant loss resulting in areas dominated by perennial grass species. How these changes cascade through linked trophic levels, however, is not well understood. We studied how grassland fertilisation propagates change through the plant assemblage into the plant-flower-visitor, plant-leaf miner and leaf miner-parasitoid networks using a year's data collection from a long-term grassland fertiliser application experiment. Our experiment had three fertiliser treatments each applied to replicate plots 15m2 in size: mineral fertiliser, farmyard manure, and mineral fertiliser and farmyard manure combined, along with a control of no fertiliser. The combined treatment had the most significant impact, and both plant species richness and floral abundance decreased with the addition of fertiliser. While insect species richness was unaffected by fertiliser treatment, fertilised plots had a significantly higher abundance of leaf miners and parasitoids and a significantly lower abundance of bumblebees. The plant-flower-visitor and plant-herbivore networks showed higher values of vulnerability and lower modularity with fertiliser addition, while leaf miner-parasitoid networks showed a rise in generality. The different groups of insects were impacted by fertilisers to varying degrees: while the effect on abundance was the highest for leaf miners, the vulnerability and modularity of flower-visitor networks was the most affected. The impact on the abundance of leaf miners was positive and three times higher than the impact on parasitoids, and the impact on bumblebee abundance was negative and double the magnitude of impact on flower abundance. Overall, our results show that while insect species richness was unaffected by fertilisers, network structure changed significantly as the replacement of forbs by grasses resulted in changes in relative abundance across trophic levels, with the direction of change depending on the type of network. Synthesis. By studying multiple networks simultaneously, we were able to rank the relative impact of habitat change on the different groups of species within the community. This provided a more holistic picture of the impact of agricultural intensification and provides useful information when deciding on priorities for mitigation.

Biofilm and microbiome response of attached growth nitrification systems across incremental decreases to low temperatures

The study investigates low temperature attached growth rates and nitrifying biofilm, biomass, and microbiome responses down to 1 °C. Two moving bed biofilm reactors (MBBR) were acclimatized from 10 °C to 1 °C by incremental decreases in temperatures. A non-linear decline in nitrification with decreasing temperatures was recorded with a kinetic threshold temperature delineated between 4 °C and 2 °C, at which a significant decline in efficiency of 22.47% occurred. An increase in biofilm thickness of 25.47% occurs between 10 °C and 4 °C, followed by lesser increases of 6.55% and 9.60% at 2 °C and 1 °C. Biofilm density decreases between 10 °C and 1 °C. An increase in embedded viable cells of 24.01% occurs between 10 °C and 4 °C, followed by lesser non-statistically relevant increases at 2 °C and 1 °C. No statistically significant change in the number of estimated species is observed; however, β-diversity analysis indicates greater microbial community shifts above the kinetic threshold followed by lesser shifts between 2 °C and 1 °C. Nitrosomanadacea and Nitrosopira are the ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) families in the biofilm with relative abundances of 3.43 ± 0.51% and 0.94 ± 0.44% respectively at 10 °C. A change in NOB relative abundance occurred between the temperatures of 10 °C and 1 °C, decreasing to 0.19 ± 0.10% above the kinetic threshold. The estimation of nitrifiers per carrier in the bioreactors, based on biofilm thickness, biomass viability and relative abundances shows an increase of 30.2% in AOB/carrier above the kinetic threshold temperature (> 4 °C) followed by lesser increases down to 1 °C.