Characterization of Springtail (Arrhopalites caecus) for Use in Soil Ecotoxicity Testing.

Springtails (subclass: Collembola) represent one of the most extensively studied invertebrate groups in soil ecotoxicology. This is because of their ease of laboratory culture, significant ecological role, and sensitivity to environmental contaminants. Folsomia candida (family: Isotomidae) is a globally widespread parthenogenetic species that is prevalent in laboratory toxicity testing with springtails. Conversely, Arrhopalites caecus (family: Arrhopalitidae), a parthenogenic globular springtail species, remains untested in soil ecotoxicology. This species is found in diverse habitats, including cave systems and forest leaf litter, and has a global distribution. The sensitivity of A. caecus to environmental contaminants, such as neonicotinoid insecticides, as well as its life history and optimal culturing conditions, are largely unknown. The present study describes the establishment of a pure A. caecus laboratory culture and characterization of its life cycle and culturing conditions. We assessed the sensitivity of A. caecus to various insecticides, including exposures to the neonicotinoid thiamethoxam in soil and through a novel feeding assay as well as to clothianidin and cyantraniliprole in spiked soil exposures. In 7- and 14-day exposures to thiamethoxam in agricultural soil, the 50% lethal concentration (LC50) values were determined to be 0.129 mg/kg dry weight and 0.010 mg/kg dry weight, respectively. The 14-day LC50 for exposure to thiamethoxam via spiked food was determined to be 0.307 mg/kg dry weight. In addition, the 28-day 50% effect concentration for inhibition of juvenile production from cyantraniliprole exposure in the same soil type was 0.055 mg/kg dry weight. Challenges encountered in using this species included susceptibility to mite infestation and low adult survival rates in the 28-day cyantraniliprole test. Environ Toxicol Chem 2024;00:1-16. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Enhancing bioretention efficiency for pollutant mitigation in stormwater runoff: Exploring ecosystem cycling dynamics amidst temporal variability.

In this study, three distinct bioretention setups incorporating fillers, plants, and earthworms were established to evaluate the operational efficiency under an ecosystem concept across varying time scales. The results revealed that under short-term operating conditions, extending the drying period led to a notable increase in the removal of NO3--N, total phosphorus (TP), and chemical oxygen demand (COD) by 5 %-7%, 4 %-12 %, and 5 %-10 %, respectively. Conversely, under long-time operating conditions, the introduction of plants resulted in a significant boost in COD removal by 10 %-20 %, while the inclusion of earthworms improved NH4+-N and NO3--N removal, especially TP removal by 9 %-16 %. Microbial community analysis further indicated the favorable impact of the bioretention system on biological nitrogen and phosphorus metabolism, particularly with the incorporation of plants and earthworms. This study provides a reference for the operational performance of bioretention systems on different time scales.

Co-exposure to deltamethrin and cyazofamid: variations in enzyme activity and gene transcription in the earthworm (Eisenia fetida).

Pesticide formulations are typically applied as mixtures, and their synergistic effects can increase toxicity to the organisms in the environment. Despite pesticide mixtures being the leading cause of pesticide exposure incidents, little attention has been given to assessing their combined toxicity and interactions. This survey purposed to reveal the cumulative toxic effects of deltamethrin (DEL) and cyazofamid (CYA) on earthworms (Eisenia fetida) by examining multiple endpoints. Our findings revealed that the LC50 values of DEL for E. fetida, following 7- and 14-day exposures, ranged from 887.7 (728-1095) to 1552 (1226-2298) mg kg-1, while those of CYA ranged from 316.8 (246.2-489.4) to 483.2 (326.1-1202) mg kg-1. The combinations of DEL and CYA induced synergistic influences on the organisms. The contents of Cu/Zn-SOD and CarE showed significant variations when exposed to DEL, CYA, and their combinations compared to the untreated group. Furthermore, the mixture administration resulted in more pronounced alterations in the expression of five genes (hsp70, tctp, gst, mt, and crt) associated with cellular stress, carcinogenesis, detoxification, and endoplasmic reticulum compared to single exposures. In conclusion, our comprehensive findings provided detailed insights into the cumulative toxic effects of chemical mixtures across miscellaneous endpoints and concentration ranges. These results underscored the importance of considering mixture administration during ecological risk evaluations of chemicals.

Molecular level toxicity effects of As(V) on Folsomia candida: Integrated transcriptomics and metabolomics analyses.

Arsenic (As) is a widespread metalloid with well-known toxicity. To date, numerous studies have focused on individual level toxicity (e.g., growth and reproduction) of As to typical invertebrate springtails in soils, however, the molecular level toxicity and mechanism was poorly understood. Here, an integrated transcriptomics and metabolomics approach was used to reveal responses of Folsomia candida exposed to As(V) of 10 and 60 mg kg-1 at which the individual level endpoints were influenced. Transcriptomics identified 5349 and 4020 differentially expressed genes (DEGs) in low and high concentration groups, respectively, and the most DEGs were down-regulated. Enrichment analysis showed that low and high concentrations of As(V) significantly inhibited chromatin/chromosome-related biological processes (chromatin/chromosome organization, nucleosome assembly and organization, etc.) in springtails. At high concentration treatment, structural constituent of cuticle, chitin metabolic process and peptidase activity (serine-type peptidase activity, endopeptidase activity, etc.) were inhibited or disturbed. Moreover, the apoptosis pathway was significantly induced. Metabolomics analysis identified 271 differential changed metabolites (DCMs) in springtails exposed to high concentration of As. Steroid hormone biosynthesis was the most significantly affected pathway. Several DCMs that related to chitin metabolism could further support above transcriptomic results. These findings further extended the knowledge of As toxic mechanisms to soil fauna and offer important information for the environmental risk assessment.

Chronic Effects of an Insect Growth Regulator (teflubenzuron) on the Life Cycle and Population Growth Rate of Folsomia candida.

Current standard toxicity tests on nontarget soil invertebrates mainly focus on the endpoints survival and reproduction. Such results are likely insufficient to predict effects at higher organizational levels, for example, the population level. We assessed the effects of exposure to the pesticide teflubenzuron on the collembolan Folsomia candida, by performing a full life-cycle experiment exposing single individuals via contaminated food (uncontaminated control and 0.2, 0.32, 0.48, 0.72, 1.08, and 1.6 mg/kg dry yeast). Several life-history traits were considered by following the growth and development of newly hatched individuals over a period of 65 days. We assessed survival, body length, time to first oviposition, cumulative egg production, and hatchability of eggs. A two-stage model was applied to calculate the population growth rate (λ) combined with elasticity analysis to reveal the relative sensitivity of λ to the effects of teflubenzuron on each life-history parameter. Body length was the least sensitive life-history parameter (median effective concentration = 1.10 mg teflubenzuron/kg dry yeast) followed by time to first oviposition (0.96 mg/kg), survival (median lethal concentration = 0.87 mg/kg), cumulative egg production (0.32 mg/kg), and egg hatchability (0.27 mg/kg). Population growth decreased with increasing concentrations of teflubenzuron (λ = 1.162/day in control to 1.005/day in 0.72 mg/kg dry yeast, with populations going extinct at 1.08 and 1.6 mg/kg dry yeast). Elasticity analysis showed that changes in juvenile survival had a greater impact on the population growth rate compared with the other life-history traits. Our study provides a comprehensive overview of individual-level effects of long-term exposure to teflubenzuron and integrates these effects to assess the potential risk to collembolan populations. Environ Toxicol Chem 2024;43:1173-1183. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Cryptic footprint of thallium in soil-plant systems; A review.

The current review highlights the complex behavior of thallium (Tl) in soil and plant systems, offering insight into its hazardous characteristics and far-reaching implications. The research investigates the many sources of Tl, from its natural existence in the earth crust to its increased release through anthropogenic activities such as industrial operations and mining. Soil emerges as a significant reservoir of Tl, with diverse physicochemical variables influencing bioavailability and entrance into the food chain, notably in Brassicaceae family members. Additionally, the study highlights a critical knowledge gap concerning Tl influence on legumes (e.g., soybean), underlining the pressing demand for additional studies in this crucial sector. Despite the importance of leguminous crops in the world food supply and soil fertility, the possible impacts of Tl on these crops have received little attention. As we traverse the ecological complexity of Tl, this review advocates the collaborative research efforts to eliminate crucial gaps and provide solutions for reducing Tl detrimental impacts on soil and plant systems. This effort intends to pave the path for sustainable agricultural practices by emphasizing the creation of Tl-tolerant legume varieties and revealing the complicated dynamics of Tl-plant interactions, assuring the long-term durability of our food systems against the danger of Tl toxicity.

The influence of soil organic matter content and substance lipophilicity on the toxicity of pesticides to the earthworm Eisenia andrei.

To account for potential differences in bioavailability (and toxicity) due to different soil organic matter (OM) contents in natural and artificial soil (AS), in the current European environmental risk assessment (ERA) a correction factor (CF) of 2 is applied to toxicity endpoints for so called lipophilic pesticides (i.e. log Kow > 2) generated from laboratory tests with soil invertebrates. However, the appropriateness of a single CF is questioned. To improve the accuracy of ERA, this study investigated the influence of soil OM content on the toxicity to the earthworm Eisenia andrei of five active substances used in pesticides covering a wide range of lipophilicity. Laboratory toxicity tests were performed in AS containing 10 %, 5 % and 2.5 % peat, and a natural LUFA 2.2 soil (4.5 % OM), assessing effects on survival, biomass change and reproduction. Pesticide toxicity differed significantly between soils. For all pesticides, toxicity values (LC50, EC50) strongly correlated with soil OM content in AS (r2 > 0.82), with toxicity decreasing with increasing OM content. Obtained regression equations were used to calculate the toxicity at OM contents of 10.0 % and 5.0 %. Model-estimated toxicity between these soils differed by factors of 1.9-3.6, and 2.1-3.2 for LC50 and EC50 values, respectively. No clear relationships between pesticide lipophilicity and toxicity-OM relationships were observed: the toxicity of non-lipophilic and lipophilic pesticides was influenced by OM content in a similar manner. The results suggest that the CF of 2 may not be appropriate as it is based on incorrect assumptions regarding the relationships between lipophilicity, OM content and toxicity. Further research should be conducted to understand the mechanistic link between toxicity and soil OM content to better define more chemically and ecologically appropriate CFs for ERA.

Structural and Functional Shifts in the Microbial Community of a Heavy Metal-Contaminated Soil Exposed to Short-Term Changes in Air Temperature, Soil Moisture and UV Radiation.

The interplay between metal contamination and climate change may exacerbate the negative impact on the soil microbiome and, consequently, on soil health and ecosystem services. We assessed the response of the microbial community of a heavy metal-contaminated soil when exposed to short-term (48 h) variations in air temperature, soil humidity or ultraviolet (UV) radiation in the absence and presence of Enchytraeus crypticus (soil invertebrate). Each of the climate scenarios simulated significantly altered at least one of the microbial parameters measured. Irrespective of the presence or absence of invertebrates, the effects were particularly marked upon exposure to increased air temperature and alterations in soil moisture levels (drought and flood scenarios). The observed effects can be partly explained by significant alterations in soil properties such as pH, dissolved organic carbon, and water-extractable heavy metals, which were observed for all scenarios in comparison to standard conditions. The occurrence of invertebrates mitigated some of the impacts observed on the soil microbial community, particularly in bacterial abundance, richness, diversity, and metabolic activity. Our findings emphasize the importance of considering the interplay between climate change, anthropogenic pressures, and soil biotic components to assess the impact of climate change on terrestrial ecosystems and to develop and implement effective management strategies.

Terrestrial Isopods Generate Microplastics from Low-Density Polyethylene Without Effects on Survival.

With concern growing regarding the impact of microplastics (MPs) on terrestrial ecosystems, it is important to assess the role invertebrates may play in the fate of MPs within these ecosystems. Commonly, MPs enter these environments through improperly discarded waste or the application of treated biosolids and/or wastewater on agricultural soils. The present study investigated whether three species of terrestrial isopod (Porcellio scaber, Porcellio laevis, and Porcellionides pruinosus) ingest plastic debris and generate MPs during exposures varying from 24 h to 14 days and whether this may have an adverse effect on their health. Test vessels were designed to expose isopods to plastic fragments in the form of polyethylene plastic foam. Isopods were exposed to plastic that was either (1) pristine, or (2) weathered in a soil and water solution prior to incorporation in test vessels. When exposed to weathered polyethylene, all three species generated MPs (minimum-maximum size values for all durations inclusive: P. laevis = 114-1673 µm, P. scaber = 99-1635 µm, P. pruinosus = 85-1113 µm) through the consumption of macroplastic fragments with no observed impact on their health. In the shorter-duration exposures, the number of MPs generated by the isopod species in the present study was highly variable between experimental vessels (minimum-maximum generated MPs for 14-day exposure: P. laevis = 25-420, P. scaber = 50-583, P. pruinosus = 48-311). However, as the exposure durations increased, there was a clear trend of increasing MP generation, indicating that the isopods continued to consume the plastic fragments as long as the surface was weathered. A significant difference in the size of generated MPs was observed as well, with smaller isopod species generating smaller MP fragments on average. The results of the present study confirm that certain species of isopod can contribute to the generation of MPs, which constitutes an additional pathway of MP exposure to soil ecosystems. Environ Toxicol Chem 2024;43:784-792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A shift from individual species to ecosystem services effect: Introducing the Eco-indicator Sensitivity Distribution (EcoSD) as an ecosystem services approach to redefining the species sensitivity distribution (SSD) for soil ecological risk assessment.

Incorporating the ecosystem services (ES) approach into soil ecological risk assessment (ERA) has been advocated over the years, but implementing the approach in ERA faces some challenges. However, several researchers have made significant improvements to the soil ERA, such as applying the species sensitivity distribution (SSD) to discern chemical effects on the soil ecosystem. Despite the considerable contributions of SSD to ERA, SSD fails to relate chemical impact on individual species to ES and account for functional redundancy as well as soil ecosystem complexity. Here, we introduce the Eco-indicator Sensitivity Distribution (EcoSD). An EcoSD fits ecological functional groups and soil processes, termed "eco-indicators," instead of individual species responses to a statistical distribution. These eco-indicators are related directly to critical ecosystem functions that drive ES. We derived an EcoSD for cadmium as a model chemical and estimated a soil ecosystem protection value (EcoPVSoil ) based on the eco-indicator dataset for cadmium from the literature. The EcoSD identified nitrogen cycling as the critical process disrupted by cadmium. A key advantage of EcoSD is that it identifies key ecological and chemical indicators of an ES effect. In doing so, it links chemical monitoring results to sensitive ecological functions. The estimated EcoPVSoil for cadmium was slightly more protective of the soil ecosystem than most regional soil values derived from this study's dataset and soil guideline values from the literature. Thus, EcoSD has proven to be a practical and valuable ES concept with the potential to serve as an initial step of the tiered ERA approach. Integr Environ Assess Manag 2023;00:1-14. © 2023 SETAC.

Precipitation seasonality and soil pH drive the large-scale distribution of soil invertebrate communities in agricultural ecosystems.

Soil invertebrates contribute significantly to vital ecosystem functions such as the breakdown of organic matter and cycling of essential nutrients, but our knowledge of their large-scale distribution in agricultural systems is limited, which hinders our ability to robustly predict how they will respond to future global change scenarios. Here, we employed metabarcoding analysis of eukaryotic 18S rRNA genes to examine the diversity and community composition of invertebrates in 528 sorghum rhizosphere and bulk soils, collected from 53 experimental field sites across China. Our results revealed that Nematoda, Arthropoda and Annelida were the dominant soil invertebrate groups in agroecosystems. Among all the climatic and soil parameters we examined, precipitation seasonality (i.e. the irregular distribution of precipitation during a normal year) had the strongest relationship with the richness of soil invertebrates, with an increase in soil invertebrate richness predicted with increasing precipitation seasonality. Mean annual precipitation and soil pH were the most important predictors of soil invertebrate community structure, with numerous invertebrate phylotypes showing either significantly positive or negative relationships with these two variables. Our findings suggest that shifts in precipitation patterns and soil pH, induced by future climate change and agricultural practices, will have important consequences for the distribution of soil invertebrate communities, with implications for agricultural ecosystem sustainability.

Coping with drought? Effects of extended drought conditions on soil invertebrate prey and diet selection by a fossorial amphisbaenian reptile.

Arid climates are characterized by a summer drought period to which animals seem adapted. However, in some years, the drought can extend for unusually longer periods. Examining the effects of these current extreme weather events on biodiversity can help to understand the effects of climate change, as models predict an increase in drought severity. Here, we examined the effects of "unusual" extended drought on soil invertebrate prey availability and on diet composition (based on fecal contents) and diet selection of a fossorial amphisbaenian, the checkerboard worm lizard Trogonophis wiegmanni. Weather data show interannual variations in summer drought duration. The abundance and diversity of soil invertebrates in spring were high, and similar to those found in a "normal" early autumn, after some rain had ended with the summer drought. In contrast, in years with "unusual" extended drought, abundance, and diversity of soil invertebrates in early autumn were very low. Also, there were seasonal changes in amphisbaenians' diet; in autumn with drought, prey diversity, and niche breadth decreased with respect to spring and autumns after some rain had fallen. Amphisbaenians did not eat prey at random in any season, but made some changes in prey selection that may result from drought-related restrictions in prey availability. Finally, in spite that amphisbaenians showed some feeding flexibility, their body condition was lower in autumn than in spring, and much lower in autumn with drought. If extended drought became the norm in the future, amphisbaenians might suffer important negative effects for their health state.

A New Method for Ecological Risk Assessment of Combined Contaminated Soil.

Ecological risk assessment of combined polluted soil has been conducted mostly on the basis of the risk screening value (RSV) of a single pollutant. However, due to its defects, this method is not accurate enough. Not only were the effects of soil properties neglected, but the interactions among different pollutants were also overlooked. In this study, the ecological risks of 22 soils collected from four smelting sites were assessed by toxicity tests using soil invertebrates (Eisenia fetida, Folsomia candida, Caenorhabditis elegans) as subjects. Besides a risk assessment based on RSVs, a new method was developed and applied. A toxicity effect index (EI) was introduced to normalize the toxicity effects of different toxicity endpoints, rendering assessments comparable based on different toxicity endpoints. Additionally, an assessment method of ecological risk probability (RP), based on the cumulative probability distribution of EI, was established. Significant correlation was found between EI-based RP and the RSV-based Nemerow ecological risk index (NRI) (p < 0.05). In addition, the new method can visually present the probability distribution of different toxicity endpoints, which is conducive to aiding risk managers in establishing more reasonable risk management plans to protect key species. The new method is expected to be combined with a complex dose-effect relationship prediction model constructed by machine learning algorithm, providing a new method and idea for the ecological risk assessment of combined contaminated soil.

The Antibacterial Activity of Rhazya stricta Extracts against Klebsiella pneumoniae Isolated from Some Soil Invertebrates at High Altitudes.

Klebsiella is a common dangerous pathogen for humans and animals and is widely present in the digestive system. The genus Klebsiella is ubiquitous, as it is endemic to surface water, soil, and sewage. In this study, 70 samples were obtained from soil-dwelling invertebrates from September 2021 to March 2022 from Taif and Shafa in different altitudinal regions of Saudi Arabia. Fifteen of these samples were identified as Klebsiella spp. The Klebsiella isolates were genetically identified as Klebsiella pneumoniae using rDNA sequencing. The antimicrobial susceptibility of the Klebsiella isolates was determined. Amplification of virulence genes was performed using PCR. In this study, 16S rDNA sequencing showed a similarity from 98% to 100% with related K. pneumonia from the NCBI database, and the sequences were deposited in the NCBI GenBank under accession numbers ON077036 to ON077050. The growth inhibition properties of ethanolic and methanolic extracts of the medicinal plant Rhazya stricta's leaves against K. pneumoniae strains using the minimum inhibitory concentration (MIC) method and disc diffusion were evaluated. In addition, the biofilm inhibitory potential of these extracts was investigated using crystal violet. HPLC analysis identified 19 components divided into 6 flavonoids, 11 phenolic acids, stilbene (resveratrol), and quinol, and revealed variations in the number of components and their quantities between extracts. Both extracts demonstrated interesting antibacterial properties against K. pneumoniae isolates. The 2 extracts also showed strong biofilm inhibitory activities, with percentages of inhibition extending from 81.5% to 98.7% and from 35.1% to 85.8% for the ethanolic and methanolic extracts, respectively. Rhazya stricta leaf extract revealed powerful antibacterial and antibiofilm activities against K. pneumoniae isolates and could be a good candidate for the treatment or prevention of K. pneumonia-related infections.

Nanoemulsion carriers for drug delivery: Assessment of environmental hazards.

Nanoemulsions (NEs) have been extensively studied as carriers for drug delivery, since these provide a good alternative to the existing non-nano systems, while promoting their target delivery and controlled release. NEs are considered safe drug carriers from a pre-clinical perspective, but there is currently no information on their ecotoxicological effects. In the present study we investigated the toxicity of a NE material (lecithin, sunflower oil, borate buffer) designed to be used as a liposomal excipient for eye drops, further referred to as (Lipid Particle:LP) LP_Eye and its dispersant (borate buffer) (LP_Eye disp.). Effects were assessed using two model species in soil ecotoxicology in LUFA 2.2 soil: Enchytraeus crypticus (Oligochaeta) and Folsomia candida (Collembola), based on the OECD standard guideline (28 days) and its extension, a longer-term exposure (56 days). The endpoints evaluated included survival, reproduction, and size. LP_Eye and LP_Eye disp. were toxic to E. crypticus and F. candida, affecting all measured endpoints. The toxicity of LP_Eye in E. crypticus seemed to be induced by the dispersant, whereas for F. candida, more sensitive, this was less explanatory. There were no indications that toxicity increased with longer exposure. Current results provide ecotoxicological data for a group of NMs that was absent, revealing toxicity to relevant environmental species. Indications were that the dispersant contributed to most of the observed effects, thus there is room to improve the formulation and achieve lower environmental impact.

More than just a substrate for mites: Moss-dominated biological soil crust protected population of the oribatid mite, Oppia nitens against cadmium toxicity in soil.

Metal-impacted sites often need aggressive ecorestoration strategies to restore a functional plant-soil system. The use of biological soil crusts for soil stabilization, moisture retention and C and N input in disturbed and contaminated soils is becoming a more common ecorestoration practice. Biological soil crusts comprise cyanobacteria, fungi, lichens, and bryophytes (mostly moss). Moss-dominated BSCs provide significant N mineralization rate in most terrestrial ecosystems. Oribatid mites or moss mites dominate moss-dominated BSCs and provide essential ecosystem services such as decomposition and nutrient cycling. We hypothesized that moss-dominated BSCs would create a high-quality habitat niche for O. nitens to resist Cd-induced toxicity. Adult mites were exposed to Cd for 28 days in soil with or without BSCs that were aged for eight months. Cadmium toxicity to mites in soil without BSCs was 1.7 and 5.4times greater than in soil with BSCs, respectively for the mites reproduction and instantaneous population growth rate (PGRi). The moss-dominated BSC did not reduce Cd bioavailability in the mites but increased the mite's resilience to Cd toxicity, likely mediated by the trophic transfer of calcium from the BSC to the mites. Our work identifies a second mechanistic avenue by which BSCs are useful for ecorestoration, i.e., the improvement of soil invertebrate physiology to resist metal stress.

Size spectra of the edaphic fauna of typical Argiudol soils of the Rolling Pampa Region, Argentina.

Background: Soil-dwelling organisms populate the spaces-referred to as interstices-between the litter on the soil surface and the pores in the soil's organo-mineral matrix. These organisms have pivotal roles in soil ecosystem functions, such as the breakdown and decomposition of organic matter, the dispersal of bacterial and fungal spores and biological habitat transformation. These functions, in turn, contribute to broader ecosystem services like carbon and nutrient cycling, soil organic matter regulation and both chemical and physical soil fertility.This study provides morphological data pertaining to a range of soil organism sizes, specifically in Argiudol soils subjected to varying levels of agricultural activity in the Rolling Pampas Region, one of the world's most extensive and fertile plains.The primary focus is on soil microarthropods-namely, Acari (mites) and Collembola (springtails)-with a body width of less than 2 mm. These organisms constitute the majority of life in the intricate soil pore network. Additionally, the study documents species of earthworms (Oligochaeta, Crassiclitelata), recognised as ecosystem engineers for their ability to create physical channels in the soil matrix and to distribute organic matter. Moreover, the study includes measurements of morphological traits of soil-dwelling "macrofauna" (organisms with a body width greater than 2 mm), which are also implicated in various soil ecosystem functions. These include population regulation by apex predators, organic matter decomposition, biogenic structure formation, nutrient mobilisation and herbivory. New information: In this paper, we report both the geographical locations and individual measurements of key morphological traits for over 7,000 specimens, covering a range of soil-dwelling organisms. These include springtails (Entognatha, Collembola), mites (Arachnida, Acari), earthworms (Oligochaeta, Crassiclitellata) and additional soil macrofauna. All specimens were collected from typical Argiudol soils located in three distinct agricultural systems characterised by varying levels of land-use intensity. To our knowledge, no other dataset exists providing this information for the Argentinian Pampas.

The effects of different temperatures in mercury toxicity to the terrestrial isopod Porcellionides pruinosus.

Climate changes and metal contamination are pervasive stressors for soil ecosystems. Mercury (Hg), one of the most toxic metals, has been reported to interact with temperature. However, compared to aquatic biota, little is known about how temperature affects Hg toxicity and bioaccumulation to soil organisms. Here, toxicity and bioaccumulation experiments were replicated at 15 °C, 20 °C, and 25 °C to understand how sub-optimal temperatures affect the toxicokinetics and toxicodynamics of Hg via soil. Genotoxicity and energy reserves were also assessed to disclose potential trade-offs in life-history traits. Results underpin the complexity of temperature-Hg interactions. Survival was determined mainly by toxicokinetics, but toxicodynamics also played a significant role in defining survival probability during early stages. The processes determining survival probability were faster at 25 °C: General Unified Threshold of Survival (GUTS) model identified an earlier/steeper decline in survival, compared to 20 °C or 15 °C, but it also approached the threshold faster. Despite potentiation of Hg genotoxicity, temperature promoted faster detoxification, either increasing toxicokinetics rates or damage repair mechanisms. This metabolism-driven increase in detoxification led to higher depletion of energy reserves and likely triggered stress response pathways. This work emphasized the need for comprehensive experimental approaches that can integrate the multiple processes involved in temperature-metal interactions.

Environmental Impact of Triclopyr on Habitat Quality in Boreal Rights-of-Way.

The indirect effects of herbicides on habitat quality in boreal ecoregions remain poorly understood. Herbicides are commonly applied on boreal rights-of-way to control vegetation below power lines, where they can indirectly enter the soil ecosystem after leaf abscission. Key soil processes such as litter decomposition and soil nutrient cycling can be influenced by altering litter chemistry and/or impacting decomposer species. Disruption of these soil processes could lead to changes in ecosystem health of boreal systems. The indirect impacts of triclopyr on habitat quality of treated boreal rights-of-way were examined through litter mass loss and quality (carbon-to-nitrogen ratios) and the response of boreal invertebrates (Folsomia candida and Oppia nitens) in microcosms and avoidance tests. Litter breakdown rates were not significantly different within a year of treatment. However, we did observe nitrogen profile differences between field-treated and untreated samples, which likely resulted from triclopyr-induced repression of natural leaf senescence processes. At field application rates, there were no differences in survival and reproduction rates of F. candida, which is key in litter breakdown. The triclopyr concentrations that caused 50% of tested F. candida and O. nitens to avoid treated litter were above field application rates. Therefore, field application rates of triclopyr are not expected to impair habitat quality and ecosystem services of boreal ecoregions based on the parameters we evaluated. Our study improves understanding of the effects of herbicide application on habitat quality and is critical for responsible herbicide use on boreal rights-of-way. Environ Toxicol Chem 2022;41:2955-2967. © 2022 SETAC.

A Functional Carbohydrate Degrading Enzyme Potentially Acquired by Horizontal Gene Transfer in the Genome of the Soil Invertebrate Folsomia candida.

Horizontal gene transfer (HGT) is defined as the acquisition by an organism of hereditary material from a phylogenetically unrelated organism. This process is mostly observed among bacteria and archaea, and considered less likely between microbes and multicellular eukaryotes. However, recent studies provide compelling evidence of the evolutionary importance of HGT in eukaryotes, driving functional innovation. Here, we study an HGT event in Folsomia candida (Collembola, Hexapoda) of a carbohydrate-active enzyme homologous to glycosyl hydrase group 43 (GH43). The gene encodes an N-terminal signal peptide, targeting the product for excretion, which suggests that it contributes to the diversity of digestive capacities of the detritivore host. The predicted α-L-arabinofuranosidase shows high similarity to genes in two other Collembola, an insect and a tardigrade. The gene was cloned and expressed in Escherichia coli using a cell-free protein expression system. The expressed protein showed activity against p-nitrophenyl-α-L-arabinofuranoside. Our work provides evidence for functional activity of an HGT gene in a soil-living detritivore, most likely from a bacterial donor, with genuine eukaryotic properties, such as a signal peptide. Co-evolution of metazoan GH43 genes with the Panarthropoda phylogeny suggests the HGT event took place early in the evolution of this ecdysozoan lineage.