Changes In Abundance Research Articles

Past Fire and Vegetation Change in the Hyperdiverse Forests of the Ecuadorian Amazon.

The Ecuadorian Amazon holds more biodiversity than most other places on Earth. Palms are a particularly dominant component of the vegetation; however, it remains unknown to what degree the pattern has persisted through time. Here, we investigate the persistence of palm dominance through time and the degree to which past human activities (e.g., fire, cultivation, and forest opening) have affected changes in palm abundances across five regions of the Ecuadorian Amazon. We analyzed soil cores (40-80 cm depth) from each region for charcoal (evidence of past fire) and phytoliths (evidence of past vegetation change). The timings of fires (based on 14C radiocarbon dates), the occurrence, recurrence, and number of fires (based on charcoal presence and abundance in samples), and the amount of change in palm abundances (based on phytoliths) varied within and between the studied regions. The charcoal and phytolith results indicate the presence of low levels of past human activity at all sites. Our results show that patterns of modern palm hyperdominance found in Amazonian forests have not been persistent through time, and that even low levels of past human activities can affect palm abundance.

Vanadium oxide clusters in substellar atmospheres. A quantum chemical study

As a refractory material, vanadia (solid V$_2$O$_5$) is likely to be found as a condensate in the atmospheres of substellar objects such as exoplanets and brown dwarfs. However, the nature of the nanometer-sized vanadium oxide clusters that partake in the nucleation process is not well understood. We aim to understand the formation of cloud condensation nuclei in oxygen-rich substellar atmospheres by calculating the relevant fundamental properties of the energetically most favorable vanadium oxide molecules and clusters and, investigate how they contribute to the formation of condensation seeds. We applied a hierarchical optimization approach in order to find the most favourable structures for clusters of (VO) N and (VO$_2$) N for N=1-10, and of (V$_2$O$_5$) N for N=1-4, and to calculate their thermodynamical potentials. The candidate geometries are initially optimized by applying classical interatomic potentials; these are then refined at the B3LYP/cc-pVTZ level of theory to obtain accurate zero-point energies and thermochemical quantities. We present previously unreported vanadium oxide cluster structures as the lowest-energy isomers. Moreover, we report revised cluster energies and their thermochemical properties. Chemical equilibrium calculations are used to asses the impact of the updated and newly derived thermodynamic potentials on the gas-phase abundances of vanadium-bearing species. In chemical equilibrium, larger clusters from different stoichiometric families are found to be the most abundant vanadium-bearing species for temperatures below sim 1000 K, while molecular VO is the most abundant between sim 1000 K and sim 2000 K. We determine the nucleation rates of each stoichiometric family for a given (T$_ gas $, p$_ gas $) profile of a brown dwarf using both classical and non-classical nucleation theory. Small differences in the revised Gibbs free energies of the clusters have a large impact on the abundances of vanadium-bearing species in chemical equilibrium at temperatures below sim 1000 K. These abundance changes subsequently have an impact on the nucleation rates of each stoichiometric family. We find that with the revised and more accurate cluster data, non-classical nucleation rates are up to 15 orders of magnitude higher than classical nucleation rates.

Phagotrophy in the nitrogen-fixing haptophyte Braarudosphaera bigelowii.

Biological nitrogen fixation provides fixed nitrogen for microbes living in the oligotrophic open ocean. UCYN-A2, the previously known symbiont of Braarudosphaera bigelowii, now believed to be an early-stage B. bigelowii organelle that exchanges fixed nitrogen for fixed carbon, is globally distributed. Indirect evidence suggested that B. bigelowii might be a mixotrophic (phagotrophic) phototrophic flagellate. The goal of this study was to determine if B. bigelowii can graze on bacteria using several independent approaches. The results showed that B. bigelowii grazed on co-occurring bacteria at a rate of 5-7 cells/h/B. bigelowii and that the overall grazing rate was significantly higher at nighttime than at daytime. Bacterial abundance changes, assessed with 16S rRNA gene amplicon sequencing analysis, may have indicated preferential grazing by B. bigelowii on specific bacterial genotypes. In addition, Lysotracker™ staining of B. bigelowii suggested digestive activity inside B. bigelowii. Carbon and nitrogen fixation measurements revealed that the carbon demand of B. bigelowii could not be fulfilled by photosynthesis alone, implying supplementation by heterotrophy. These independent lines of evidence together revealed that B. bigelowii engages in phagotrophy, which, beyond serving as a supplementary source of carbon and energy, may also facilitate the indirect assimilation of inorganic nutrients.

Detection of pharmacolipidodynamic effects following the intravenous and oral administration of gefitinib to C57Bl/6JRj mice by rapid UHPLC-MS analysis of plasma

Omics-based biomarker technologies, including metabolic profiling (metabolomics/metabonomics) and lipidomics, are making a significant impact on disease understanding, drug development, and translational research. A wide range of patho-physiological processes involve lipids and monitoring changes in lipid abundance can give valuable insights into mechanisms of drug action, off target pharmacology and toxicity. Here we report changes, detected by untargeted LC–MS, in the plasma lipid profiles of male C57Bl/6JRj mice following the PO and IV administration of the epidermal growth factor receptor (EGFR) inhibitor gefitinib. Statistical analysis of the data obtained for both the IV and PO samples showed time-related changes in the amounts of lipids from several different classes. The largest effects were associated with a rapid onset of these changes following gefitinib administration followed by a gradual return by 24 h post dose to the type of lipid profile seen in predose samples. Investigation of the lipids responsible for the variance observed in the data showed that the PI, PC, LPC, PE and TG were subject to the largest disruption with both transient increases and decreases in relative amounts seen in response to administration of the drug. The pattern of the changes in the relative abundances of those lipids subject to variation appeared to be correlated to the pharmacokinetics of gefitinib (and its major metabolites). These observations support the concept of a distinct pharmacolipidodynamic relationship between drug exposure and plasma lipid abundance.

Inter-generational consistency of the ectomycorrhizal fungal community in a mixed pine-cedar post-fire stand.

The mutualistic interaction between trees and ectomycorrhizal fungi (EMF) can have a major effect on forest dynamics and specifically on seedling establishment. Here, we compared the EMF community composition associated with the roots of young saplings and mature trees of two co-habiting Pinaceae: Pinus halepensis and Cedrus deodara growing together in a post-fire forest plot, using fungal ITS metabarcoding. We found that the differences in the EMF community between the two sapling groups were mostly attributed to changes in the relative abundance of specific fungal species with little species turnover. Specifically, Tomentella showed high abundance on pine roots while Tuber, Russula and Sebacina were more common on the roots of cedars. The physical proximity to a specific host species was correlated with the EMF community composition of young saplings. Specifically, regardless of the sapling's own identity, the roots of saplings growing next to mature cedars had higher abundance of Tuber species while Tomentella coerulea, Russula densifolia and Tuber nitidum dominated saplings next to mature pines. Cedar saplings' shoot structure was correlated with a specific EMF species. Overall, these results suggest that when germinating next to mature trees, the EMF community of saplings could be determined by extrinsic factors such as the small-scale distribution of mature trees in the forest.

Metabolomic characterization of human glioblastomas and patient plasma: a pilot study.

Glioblastoma (GBM) is a clinically challenging primary brain tumor with poor survival outcome despite surgical resection and intensive chemoradiation. The metabolic heterogeneity of GBM can become biomarkers for treatment response, resistance, and outcome prediction. The aim of the study is to investigate metabolic distinctions between primary and recurrent GBM tissue and patient plasma to establish feasibility for metabolic profiling. A single-center cohort study analyzed tissue and blood samples from 15 patients with GBM using untargeted metabolomic/lipidomic assays. Metabolomic, lipidomic, and biogenic amine analyses were conducted on GBM tissue and patient plasma at diagnosis and recurrence using untargeted mass spectrometry. The study utilized a small but longitudinally collected cohort to evaluate alteration in metabolites, lipids, and biogenic amines between specimens at diagnosis and recurrence. Exploratory analysis revealed significant alteration in metabolites, lipids, and biogenic amines between diagnostic and recurrent states in both tumor and plasma specimens. Notable metabolites differed at recurrence, including N-alpha-methylhistamine, glycerol-3-phosphate, phosphocholine, and succinic acid in tissue, and indole-3-acetate, and urea in plasma. Principal component analysis revealed distinct metabolomic profiles between tumor tissue and patient plasma. Distinct metabolic profiles were observed in GBM tissue and patient plasma at recurrence, demonstrating the feasibility of using metabolomic methodologies for longitudinal studies. One patient exhibited a unique tumor resistance signature at diagnosis, possibly indicating a high-risk metabolomic phenotype. In this small cohort, the findings suggest the potential of metabolomic signatures of GBM tissue and patient plasma for risk stratification, outcome prediction, and the development of novel adjuvant metabolic-targeting therapies. The findings suggest metabolic discrepancies at diagnosis and recurrence in tissue and plasma, highlighting potential implications for evaluation of clinical response. The identification of significant changes in metabolite abundance emphasizes the need for larger studies using targeted metabolomics to validate and further explore these profiles.

Benthic communities under methane gradient in the Laptev and East Siberian seas

IntroductionMethane seeps influence surrounding benthic communities in different ways from slight changes in benthic abundance and biomass to major altering the species composition.Materials and MethodsWe studied benthic communities of 14 methane seep flares in Laptev and East Siberian seas with comparative analysis of species composition and abiotic parameters at the nearby areas not affected by methane seeps. The species diversity was comparable at seep and non-seep sites varying from 3.9 to 39.6 taxa per 100 individuals and from 4.5 to 34.8 taxa per 100 individuals, correspondingly.ResultsThe Laptev Slope community corresponds with the Polychaeta-community, encircling the upper continental slope area of the entire Siberian Arctic. The Lower Shelf community described in this study apparently corresponds with the Ophiocten sericeum community identified in the shelf areas of the Kara, Laptev and East Siberian seas. The Upper Shelf community is mostly inhabited by the bivalves species such as Portlandia arctica, Ennucula tenuis and Astarte montagui communities. The Estuarine community, which is the poorest by diversity but has high values of abundance and biomass is directly influenced by the Lena River runoff in terms of lower salinities and higher sedimentation rates.DiscussionThroughout the study area, the differences between the Estuarine, Upper Shelf, Lower Shelf and Laptev Slope communities exceeded the differences between the seep and background non-seep areas. Several taxa demonstrated correlations with different environmental factors, including the latitude, depth, temperature, salinity, pH and methane content, not depending on the revealed benthic community. Eight taxa demonstrated correlations with the methane content measured at different sediment depths. Two siboglinids taxa demonstrated high abundances at stations with highest methane content deep in the sediment. At the Siberian shelf, our geochemical data for siboglinid habitats are the first to be published so far.

Conversion of coastal marsh to aquaculture ponds altered soil ammonia oxidiser community and decreased ammonia oxidation potential

AbstractIntroductionAs a crucial component of the nitrogen cycle, ammonia oxidation in soil can be driven by canonical ammonia‐oxidising archaea (AOA) and bacteria, as well as complete ammonia oxidiser (CMX Nitrospira). Land use change can disrupt and alter the soil microbial community and the nitrogen cycle.Materials & MethodsWe compared the soil ammonia‐oxidising microorganisms and ammonia oxidation potentials in a coastal marsh and nearby reclaimed aquaculture ponds, monthly over a 10‐month period in southeastern China. The abundance of ammonia oxidisers was assessed by real‐time quantitative PCR and the community structure of CMX Nitrospira was evaluated by high‐throughput sequencing.ResultsThe ammonia oxidiser community was dominated by AOA in the marsh (91%) and was made up of similar proportions of AOA and CMX Nitrospira in the aquaculture ponds (46%–47%). The CMX Nitrospira community structure changed significantly between habitat types, mainly driven by opposite change in relative abundance of clade B versus clades A.2 and A.3. Aquaculture reclamation decreased the soil potential ammonia oxidation rate (PAO) by an order of magnitude, and AOA was the only significant predictor of PAO among all ammonia oxidiser groups.ConclusionOur results suggest that aquaculture reclamation from coastal marshes would significantly alter the soil ammonia oxidiser community and decrease ammonia oxidation rate, and CMX Nitrospira appear to play a relative larger role in nitrogen cycling in aquaculture ponds.

Cross-Validation of Lipid Structure Assignment Using Orthogonal Ion Activation Modalities on the Same Mass Spectrometer.

The onset and progression of cancer is associated with changes in the composition of the lipidome. Therefore, better understanding of the molecular mechanisms of these disease states requires detailed structural characterization of the individual lipids within the complex cellular milieu. Recently, changes in the unsaturation profile of membrane lipids have been observed in cancer cells and tissues, but assigning the position(s) of carbon-carbon double bonds in fatty acyl chains carried by membrane phospholipids, including the resolution of lipid regioisomers, has proven analytically challenging. Conventional tandem mass spectrometry approaches based on collision-induced dissociation of ionized glycerophospholipids do not yield spectra that are indicative of the location(s) of carbon-carbon double bonds. Ozone-induced dissociation (OzID) and ultraviolet photodissociation (UVPD) have emerged as alternative ion activation modalities wherein diagnostic product ions can enable de novo assignment of position(s) of unsaturation based on predictable fragmentation behaviors. Here, for the first time, OzID and UVPD (193 nm) mass spectra are acquired on the same mass spectrometer to evaluate the relative performance of the two modalities for lipid identification and to interrogate the respective fragmentation pathways under comparable conditions. Based on investigations of lipid standards, fragmentation rules for each technique are expanded to increase confidence in structural assignments and exclude potential false positives. Parallel application of both methods to unsaturated phosphatidylcholines extracted from isogenic colorectal cancer cell lines provides high confidence in the assignment of multiple double bond isomers in these samples and cross-validates relative changes in isomer abundance.

Dynamics of antibiotic resistance genes during manure composting: Reduction in herbivores manure and accumulation in carnivores

The elevated levels of antibiotic resistance genes (ARGs) in livestock manure represent a significant threat to both the environment and human health. Composting has been recognized as an effective strategy to mitigate the abundance of ARGs in manure. However, notable rebounds in ARGs abundance have been observed during this process. This study explored the changes in ARGs abundance and the underlying influencing factors during the composting of carnivore (chicken and pig) and herbivore (sheep and cow) manures, along with mushroom residues. The findings revealed that the total relative abundance of ARGs increased by 6.96 and 10.94 folds in chicken and pig manure composts, respectively, whereas it decreased by a remarkable 91.72% and 98.37% in sheep and cow manure composts. Nitrogen content emerged as the primary physicochemical factors governing the abundance of ARGs in chicken and pig manure composts. Conversely, carbon content played a pivotal role in determining ARGs abundance in chicken and pig manure composts. Furthermore, the presence of dominant hosts, such as Corynebacterium, Bacillus, and Clostridium, along with emerging bacteria like Thermobifida, Saccharomonospora, and Actinomadura, contributed significantly to the enrichment of total ARGs, including tetG, tetO, tetX, and sul2, in chicken and pig manure composts. The coexistence of these genes with mobile genetic elements and a plethora of host bacteria, coupled with their high abundance, renders them particularly high-risk ARGs. On the other hand, the observed decrease in the abundance of total ARGs in sheep and cow manure composts can be attributed to the decline in the population of host bacteria, specifically Atopostipes, Psychrobacter, and Corynebacterium. Collectively, these results provide crucial insights into the management of ARGs risks and offer essential theoretical support for enhancing the safe utilization of organic fertilizer in agriculture.

From sensing to acclimation: The role of membrane lipid remodeling in plant responses to low temperatures.

Low temperatures pose a dramatic challenge to plant viability. Chilling and freezing disrupt cellular processes, forcing metabolic adaptations reflected in alterations to membrane compositions. Understanding the mechanisms of plant cold tolerance is increasingly important due to anticipated increases in the frequency, severity, and duration of cold events. This review synthesizes current knowledge on the adaptive changes of membrane glycerolipids, sphingolipids, and phytosterols in response to cold stress. We delve into key mechanisms of low-temperature membrane remodeling, including acyl editing and headgroup exchange, lipase activity, and phytosterol abundance changes, focusing on their impact at the subcellular level. Furthermore, we tabulate and analyze current gycerolipidomic data from cold treatments of Arabidopsis, maize, and sorghum. This analysis highlights congruencies of lipid abundance changes in response to varying degrees of cold stress. Ultimately, this review aids in rationalizing observed lipid fluctuations and pinpoints key gaps in our current capacity to fully understand how plants orchestrate these membrane responses to cold stress.

Effects of dietary zinc on the gut microbiome and resistome of the gestating cow and neonatal calf

Zinc is an essential trace element required in the diet of all species. While the effects of zinc have been studied in growing calves, little is known about the effect of zinc on the microbiota of the gestating cow or her neonatal calf. Understanding factors that shape the gut health of neonatal animals and evaluating the effect of dietary supplements in adult gestating animals is important in promoting animal health and informing feeding practices. The aims of this study were to determine the effect of dietary zinc on the microbiota and resistome of the gestating cow and calf. Gestating cows received standard (40 ppm) or high (205 ppm) dietary zinc levels from dry off to calving. Fecal samples were collected from cows upon enrollment and at calving and from neonatal calves. Fecal samples underwent 16S rRNA sequencing and a subset also underwent shotgun metagenomic sequencing. The effect of zinc supplementation on the diversity and composition of the cow and calf microbiome and resistome was assessed. Alpha and beta diversity and composition of the microbiota were significantly altered over time but not by treatment in the cows, with alpha diversity decreasing and 14 genera found at significantly higher relative abundances at calving compared to enrollment. Levels of 27 antimicrobial resistance genes significantly increased over time. Only a small number of taxa were differentially expressed at calving in treatment and control groups, including Faecalibacterium, Bacteroides, Turicibacter, and Bifidobacterium pseudolongum. No effect of the dam’s treatment group was observed on the diversity or composition of the neonatal calf microbiota. The calf resistome, which was relatively rich and diverse compared to the cow, was also unaffected by the dam’s treatment group. The impact of high levels of dietary zinc thus appeared to be minimal, with no observed changes in alpha or beta diversity, and few changes in the relative abundance of a small number of taxa and antimicrobial resistance genes.

Discovery of giant and conventional magnetofossils bookending Cretaceous Oceanic Anoxic Event 2

Conventional magnetofossils are the remains of magnetotactic bacteria and giant magnetofossils are the remains of iron biomineralizing organisms that have not yet been identified. We report the oldest robust conventional and giant magnetofossil records, ~97 Ma, from marine sediments drilled in Holland Park, Virginia, USA. The Holland Park core records the Cenomanian-Turonian boundary and Oceanic-Anoxic Event 2 (OAE2). Magnetic datasets indicate single domain magnetite within the clay-rich sediments bookending OAE2. Electron microscopy images from these intervals highlight conventional and giant magnetofossil morphologies, including three potentially new giant magnetofossil morphologies: seeds, squash, and spades. There is an overall high abundance and morphological disparity of magnetofossils at Holland Park. However, we observe abundance, disparity, and preservation changes between the magnetofossil assemblages bookending OAE2. Our observations provide clues toward understanding the ecological thresholds of the enigmatic organisms that produce giant magnetofossils and evidence that magnetofossils may be widely distributed in the geologic record.

Phenotypic response of a geographically expanding species, Scomber colias: Clues in the fish otolith shape

During the last decades, there has been a growing interest in the Atlantic chub mackerel, Scomber colias, owing to its northward expansion across the East Atlantic Ocean. This trend has been observed from regions of higher abundance off northwest Africa to the waters of the Atlantic Iberian and the Mediterranean Sea. Changes in abundance and spatial distribution of Atlantic chub mackerel have been previously studied and various theoretical models have been proposed to elucidate the changes in its abundance and biomass. However, within this fishing context, only a limited number of studies have attempted to understand how this species has responded at both the individual and population levels to the changing environmental conditions. The phenotypic variability of 1660 individuals of S. colias collected from the Canary Islands, Madeira, the Cantabrian Sea and the Central-Northern Mediterranean Sea was examined, with a specific focus on otolith shape. We identified six morphotypes classified into two groups and associated to the four analyzed regions. Despite of the occurrence of shared phenotypes in varying proportions among the different fishing grounds, this classification might be explained by the adaptation of certain morphotypes to specific environmental conditions and the migratory behavior of this species. The morphotypes M1-M5 were more abundant in the warmer waters of Madeira-Canary Islands region and M6 in the colder waters of Ligurian-Cantabrian. It is plausible that the former set may represent resident contingents, while morphotypes M2-M3 and M4 are likely to exhibit migratory behavior. Therefore, we suggest a complex metapopulation structure, where different contingents coexist.

Estimating fox abundance using the simultaneous count method

AbstractFeral foxes Vulpes vulpes are a major threat to Australian wildlife and assessing the success of control programs requires comparison of abundance before and after control. While camera traps are often used to assess fox activity, estimating abundance is difficult due to the inability to distinguish individuals requiring an “unmarked” methodology. We tested the “simultaneous count method” which requires samples to be independent during the sampling period, that is, 24 h, while allowing lack of independence between sampling periods. This enables repeat detections of animals to estimate abundance. We tested the method on camera data collected over 5 years at Oolambeyan National Park, New South Wales, during a fox control program and conclude that the method has merit. We were able to statistically measure an effect of change in abundance from a median of 57 to 2, however, estimation of detectability was erratic.

Digestion, nitrogen excretion and rumen microbial communities in beef cattle, and in vitro methane output, of fresh temperate grass with or without citrus pulp supplementation

The effects of supplementing grass with a high-energy, low-protein concentrate on intake, rumen fermentation, rumen microbial communities, apparent total tract digestibility and N-balance in beef cattle, and rumen fermentation and methane output in vitro, were studied. Sixteen Charolais steers (mean live weight (s.d.) 564 (24.3) kg)), were used in a completely randomised block design experiment, and offered either zero-grazed perennial ryegrass (Lolium perenne L.) ad libitum (GO), or the same grass with 2.25 kg citrus pulp dry matter (DM) daily (GCP). During the measurement phase, DM intake was restricted at 0.85 of their pre-determined intake. The same diets were incubated in an eight-vessel RUSITEC system. Supplementation decreased grass DM intake (6.59 vs. 7.54 kg/d) but increased total DM intake by 0.95 kg/d (P < 0.01). Rumen pH (P = 0.05) and NH3 concentration (P < 0.05) decreased, and total volatile fatty acid (VFA) concentrations (P < 0.01), molar proportions of propionate (P = 0.08) and butyrate (P < 0.05) increased for GCP compared to GO. Supplementation significantly altered the overall rumen microbial community structure compared to GO, driven principally by changes in relative abundance of Prevotella, Methoanobrevibacter and Lachnospiraceae genera. Plasma urea concentration was lower (P < 0.05) for GCP than GO. There was no effect (P > 0.10) of supplementation on apparent total tract digestibility of DM, OM and ADFom, but aNDFom digestibility tended to be lower (P = 0.07) and crude protein (N × 6.25) digestibility was lower (P < 0.01) for GCP compared to GO. Nitrogen intake (200 g/d) did not differ (P > 0.05) between treatments. Faeces N loss was 9 g/d greater (P < 0.01), and urine (P < 0.01) and total (P < 0.05) N losses were 22 and 13 g/d lower, respectively, for GCP compared to GO. In terms of N-balance (g/kg N intake), faecal N excretion was greater and urinary N excretion was lower (P < 0.01) resulting in a greater N use efficiency (P = 0.06) for GCP than GO. In vitro rumen NH3 concentrations were lower (P < 0.01) for GCP compared to GO, whereas in vitro rumen pH, lactic acid, VFA concentrations and molar proportions, and methane and total gas output did not differ (P > 0.05) between treatments. Supplementing grass with a low-protein, high-energy feed may be a strategy to reduce urinary and total N excretion in beef cattle grazing temperate grass pasture.

Microbiome variations induced by delta9-tetrahydrocannabinol predict weight reduction in obese mice

IntroductionObesity and high-fat diets induce consistent alterations in gut microbiota composition. Observations from epidemiological reviews and experiments also illustrate weight regulation effects of delta9-tetrahydrocannabinol (THC) with microbiome shifts. Therefore, we investigated the weight-loss potential of THC in obese mice models and to elucidate the contribution of specific gut microbiome changes in THC-induced weight loss.MethodsHigh-fat diet induced obese mice were treated with oral THC supplementation for two weeks and compared with controls. In addition to measuring weight, fecal samples were obtained at various timepoints, sequenced for bacterial 16s rRNA content and analyzed using QIIME2. Alpha and beta diversity were computed followed by linear mixed effects (LME) modeling of bacterial relative abundance relationship to THC treatment and weight change.ResultsIn both male and female mice, the THC group had significantly greater average weight loss than controls (−17.8% vs. −0.22%, p&amp;lt;0.001 and −13.8% vs. +2.9%, p&amp;lt;0.001 respectively). Male mice had 8 bacterial taxonomic features that were both significantly different in relative abundance change over time with THC and correlated with weight change. An LME model using three bacterial features explained 76% of the variance in weight change with 24% of variation explained by fixed effects of feature relative abundance alone. The model also accurately predicted weight change in a second male mouse cohort (R=0.64, R2=0.41, p=&amp;lt;0.001). Female mice had fewer significant predictive features and were difficult to model, but the male-produced 3-feature model still accurately predicted weight change in the females (R=0.66, R2=0.44, p&amp;lt;0.001).ConclusionUsing a stepwise feature selection approach, our results indicate that sex-specific gut microbiome composition changes play some role in THC-induced weight loss. Additionally, we illustrated the concept of microbiome feature-based modeling to predict weight changes.

Hurricanes temporarily weaken human-ecosystem linkages in estuaries.

Intense disturbances such as hurricanes may drastically affect ecosystems, producing both acute and long-term changes along coastlines. By disrupting human activities (e.g., fishing), hurricanes can provide an opportunity to quantify the effects of these activities on coastal ecosystems. We performed predator-exclusion experiments on oyster reefs in 2016, one-year before a category-4 hurricane ("Harvey") and again in 2018 one-year post-hurricane where the storm made landfall. Additionally, we examined 8 years (2011-2018) of fisheries-independent data to gauge how fishing pressure and fish populations were affected by the storm in three locations that varied in storm impacts. In the month following Hurricane Harvey, fishing effort dropped by 90% in the area with wind and flooding damage, and predatory fish species commonly targeted by anglers were 300% more abundant than the year prior to the hurricane. The locations without damage to fishing infrastructure did not experience declines in fishing pressure or changes in fish abundance, regardless of flooding disturbance. Reef fish and invertebrate communities directly affected by the storm were significantly different after the hurricane and were ~ 30% more diverse. With low fishing pressure, sportfish CPUE were 1.7-6.9 × higher immediately after the hurricane. Intermediate consumers, such as crabs that prey on oysters, were 45% less abundant and 10% smaller. These results indicate that hurricanes can temporarily disrupt human-ecosystem linkages and reconstitute top-down control by sportfish in estuarine food webs. Disturbance events that interrupt or weaken those interactions may yield indirect ecological benefits and provide insights into the effects of human activities on food webs.

Mapping global distributions of clay-size minerals via soil properties and machine learning techniques

Clay-size mineral is a vital ingredient of soil that influences various environment behaviors. It is crucial to establish a global distribution map of clay-size minerals to improve the recognition of environment variations. However, there is a huge gap of lacking some mineral contents in poorly accessible remote areas. In this work, machine learning (ML) approaches were conducted to predict the mineral contents and analyze their global abundance changes through the relationship between soil properties and mineral distributions. The average content of kaolinite, illite, smectite, vermiculite, chlorite, and feldspar were predicated to be 28.69 %, 22.30 %, 12.42 %, 5.43 %, 5.03 %, and 1.44 % respectively. Model interpretation showed that topsoil bulk density and drainage class were the most significant factors for predicting all six minerals. It could be seen from the feature importance analysis that bulk density notably reflected the distribution of 2:1 layered minerals more than that of 1:1 mineral. High drainage favored secondary minerals development, while low drainage was more benefited for primary minerals. Moreover, the content variation of different minerals aligned with the distribution of corresponding soil properties, which affirmed the accuracy of established models. This study proposed a new approach to predict mineral contents through soil properties, which filled a necessary step of understanding the geochemical cycles of soil-related processes.

Relating microbial community composition to treatment performance in an ozone-biologically active carbon filtration potable reuse treatment train

Treatment trains that couple ozone (O3) with biologically active carbon (BAC) filtration are of interest as a lower cost, more sustainable, membrane-free approach to water reuse. However, little is known about the microbial communities that are the fundamental drivers of O3-BAC treatment. The objective of this study was to demonstrate microbial community profiling as a diagnostic tool for assessing the functionality, biological stability, and resilience of coupled physical, chemical, advanced oxidative and biological processes employed in water reuse treatment. We utilized 16S rRNA gene amplicon sequencing to profile the bacterial microbiota over time throughout a potable reuse train employing coagulation, flocculation, sedimentation, ozonation, BAC filtration, granular activated carbon (GAC) adsorption, and UV disinfection. A distinct baseline microbiota was associated with each stage of treatment (ANOSIM, p < 0.05, r-stat = 0.52), each undergoing succession with time and operational shifts. Ozonation resulted in the sharpest shifts (i.e., 83.3 % average change in Genus level relative abundances, when adjusted O3:TOC ratio > 1), and also variance, in microbial community composition. Adjustment in O3:TOC ratios, temperature, filter-aid polymer, monochloramine quenching agent, and empty-bed contact time also resulted in measurable changes in the baseline microbial community composition of individual processes, but to a lesser degree. Of these, supplementation of nitrogen and phosphorus resulted in the strongest bifurcation, especially in the microbial communities inhabiting the BAC (ANOSIM: p < 0.05, BAC5 r-stat = 0.32; BAC10 r-stat = 0.54) and GAC (ANOSIM: p < 0.05, GAC10 r-stat = 0.54; GAC20 r-stat = 0.63) units. Additionally, we found that the BAC microbial community was responsive to an inoculation of microbially active media, which resulted in improved TOC removal. The findings of this study improve understanding of bacterial dynamics occurring in advanced water treatment trains and can inform improved system design and operation.