Publications

Plastics and herbicides represent two of the most extensive and persistent anthropogenic contaminants entering agroecosystems. The synergistic interaction of these pollutants on soil health, however, remains poorly understood. For the first time, we investigated the behavior of a common selective triazine herbicide (simazine) in soil containing 0%, 1%, 5%, 10%, and 20% (w/w) of two commonly found microplastics, namely polyethylene (PE) and polyvinyl chloride (PVC). The mineralization of 14 C‐labeled simazine in soil decreased with the presence of both PE and PVC as indicated by the lower total 14 CO 2 loss. Consequently, the half‐life of simazine increased in the presence of microplastics, although there was little difference between microplastic types. The ratio of fungi‐to‐bacteria in the soil increased by 9%–18% after 1% of microplastics addition, while enzyme activities involved in C‐cycling decreased by 20%–46% in soil amended with PVC relative to the control. Further, enzyme activities were negatively correlated with the half‐life of simazine when added with PVC. Therefore, we ascribe the repression in simazine degradation to changes in microbial community structure (increased fungi‐to‐bacteria ratio) and reduced enzyme activities. Overall, microplastics accumulation in soil decreases herbicide breakdown resulting in herbicide residuals remaining, which in turn, may increase their risk of reaching ground or surface waters.

Climate change is intensifying extreme weather events in coastal areas, leading to more frequent discharge of untreated wastewater containing human viruses into coastal waters. This poses a health risk, especially during heatwaves when bathing activity increases. A study examined the survival and viability of seven common wastewater viruses in seawater at different temperatures. Viral genomes were quantified using direct qPCR, whilst viability was assessed using Capsid Integrity qPCR. Results showed that T90 values from direct qPCR were much higher than those from CI-qPCR, suggesting that risk mitigation should be based on viral integrity tests. All viruses remained potentially viable for at least 72 h in environmental seawater and longer in sterile artificial seawater, highlighting the importance of biotic processes in viral inactivation. Viral persistence decreased with increasing temperature. Whilst heatwaves may partially reduce risks from human viral pathogens in coastal waters, they do not eliminate them entirely.

The antimicrobial action of chitosan and functionalized chitosan derivatives is well known; however, limited research has been undertaken on its use in meat environments. In this study, the antibacterial activity of a newly-developed arginine-functionalized chitosan was tested against pathogenic Escherichia coli O157 in chicken juice. The chicken juice was representative of the liquid which accumulates in food packaging and which is frequently implicated in food poisoning incidents. Aliquots of chicken juice (50 ml) were inoculated with a lux-marked strain of E. coli O157 to approximately 8.75 log10 CFU ml−1. Samples were subsequently mixed with chitosan-arginine of varying concentrations (0–500 mg l−1) and incubated at 4 or 20 °C to mimic refrigeration and room temperatures, respectively. Pathogen persistence and metabolic activity (indexed by bioluminescence measurements) were subsequently quantified in the liquor at 0 (immediately after mixing), 3, 12, 24, 48, and 72 h post-incubation. The presence of chitosan-arginine significantly reduced both the numbers and metabolic activity of the pathogen in a dose-dependent manner with greater inhibition seen at higher concentration. In addition, it also suppressed the growth of general food spoilage bacteria, reduced malodor and prevented pathogen re-growth up to 72 h. The results imply that incorporating water soluble chitosan-arginine into packaging may help maintain both product shelf life and freshness as well as minimize the risk of food poisoning in both retail outlets and domestic homes.

Soils in temperate agroecosystems are frequently exposed to extremes of moisture and temperature during which time soil functioning may be negatively affected. The aim of this study was to directly compare the effects of a single dry-wet or freeze-thaw (−5 °C or −20 °C) cycle on extracellular enzyme activity and soil organic matter turnover. We measured the activity of six enzymes before and after imposing the freeze-thaw or dry-rewet events. Our results showed that drying had a much greater impact on total enzyme activity than a −20 °C freezing event (38 vs. 10% reduction, respectively), while freezing at −5 °C had no appreciable effect. Enzyme activity recovered back to control levels relatively quickly which we ascribe to de novo exoenzyme production (within 3 d for the −20 °C freeze-thaw treatment and 14 d for the dry-wet treatment). We added 14C-labelled plant residues to the soil prior to imposing the same thermal or moisture stress events. Monitoring residue decomposition before and after imposing the treatments indicated that none of the stress regimes greatly affected organic matter turnover rates. Our results did reveal, however, a pulse of 14CO2 which was produced during the drying and freezing events themselves. We ascribe this to a shift in microbial metabolism and the production of stress avoidance metabolites (e.g. osmo- and cryo-protectants, membrane lipids). Our work highlights that extreme weather events may affect exoenzyme activity, however, these responses are transitory and are unlikely to greatly affect soil organic matter cycling unless they occur at high frequency.

Organo-mineral interactions have been hypothesized to play a major role in biogeochemical cycling and pedogenesis in some forest soils. These processes are likely to be controlled to some extent by their persistence in soil, however, the factors regulating their bioavailability remain poorly understood. Therefore, we investigated the microbial utilization of 14C-labeled citrate in glass bead filled bioreactors containing a biofilm developed from an inoculum from an acid forest soil. The removal of Al-citrate in the bioreactors was negligible compared to the rate of citrate removal in the absence of Al. There was no evidence that in the short-term the microbial community adapted to increase the utilization of Al-citrate. In bioreactors filled with a Picea abies forest soil (Haplic Arenosol) the rates of citrate utilization were always slightly higher than that of Al-citrate. We conclude that complexation of citrate by metals such as Al may have a significant effect on their role in soil biogeochemical cycles.

The <i>Encyclopaedia Cloacae</i> is a novel and centralised digital platform designed to support and advance wastewater-based epidemiology (WBE) by cataloguing pathogens detectable in wastewater and their relevance to public health surveillance. The platform is hosted on the EU Wastewater Observatory for Public Health (EU4S) website, where it is populated with peer-reviewed research through a structured workflow under harmonised criteria which address the presence of pathogens in human excreta, detectability in wastewater, and integration into public health systems. This tri-criteria approach ensures that the database is both scientifically robust and operationally actionable. Complemented by the <i>Visualising the Invisible</i> dashboard, the platform offers geospatial insights into global WBE research activity. By consolidating peer-reviewed evidence on pathogen detectability in wastewater and human excreta, the <i>Encyclopaedia Cloacae</i> enables early detection of infectious diseases, whether already known or newly emerging. The continuously updated repository and geospatial dashboards help to identify surveillance gaps and research hotspots, to support timely public health responses, enhance pandemic preparedness, and strengthen global health security. In addition, it supports One Health strategies, connecting the health of humans, animals, and the shared environment. This article outlines the platform's architecture, data curation methodology, and future directions, including automation and expansion to encompass broader health determinants such as antimicrobial resistance and chemical hazards.

Wastewater-based epidemiology (WBE) is a crucial tool for health and environmental monitoring, providing real-time data on public health indicators by analysis of sewage samples. Ensuring the integrity of these samples from collection to analysis is paramount. This study investigates the effects of different cold-storage conditions on the integrity of wastewater samples, focusing on both microbiological markers (such as extractable nucleic acids, SARS-CoV-2, and crAssphage) and physicochemical parameters (including ammonium, orthophosphate, pH, conductivity, and turbidity). Composite samples from the combined raw wastewater influent from five wastewater treatment works in South Wales, UK, were stored at 4°C, -20°C, and -80°C, and subjected to up to six freeze-thaw cycles over one year. The study found significant effects of storage temperature on the preservation of certain WBE markers, with the best yield most frequently seen in samples stored at -80°C. However, the majority of WBE markers showed no significant difference between storage at -80°C or at 4°C, demonstrating that it may not always be necessary to archive wastewater samples at ultra-low temperatures, thus reducing CO

Soils harbour high levels of microbial diversity, underpinning their ability to provide key soil functions and ecosystem services. The extreme variety of soil microbial life is often explained by reference to the physical and chemical heterogeneity of the soil environment. However, detailed understanding of this link is still lacking, particularly as micro-scale studies are difficult to scale up to the soil profile or landscape level. To address this, we used soil samples collected from a wide range of temperate oceanic habitats (e.g. arable, grassland, coniferous and deciduous woodland, heathland; 335 sites in total) to evaluate the link between soil texture and microbial diversity. Soil particle size distribution was measured in each sample using laser granulometry (i.e. sand, silt, clay), while the diversity of bacterial and fungal communities were determined by metabarcoding with an Illumina MiSeq using16S and ITS1 taxonomy marker gene regions, respectively. Multifractal analysis of the soil particle size distribution was then used to describe the heterogeneity of the soil particle sizes. Overall, our results showed no impact of habitat type upon textural heterogeneity indicating that it is an aspect of soil quality resistant to management decisions. Using a structural equation modelling approach, we show that soil textural heterogeneity positively influences bacterial diversity but had little impact upon fungal diversity. We also find that textural composition impacts both bacterial and fungal composition, with many specific microbial taxa showing co-occurrence relationships with clay and fine-silt sized particles. Our results strongly indicate that soil textural heterogeneity influences microbial community diversity regardless of soil management practices and biophysical activities. The close linkages between different groups of soil organisms can obscure the mechanisms driving the development of biodiversity, however, it is clear that the soil physical environment has differential impacts on organisms with different life history strategies.

Earthworms ingest large amounts of soil and have the potential to radically alter the biomass, activity, and structure of the soil microbial community. In

Plant S deficiency is common, but the role of S-containing amino acids such as cysteine in plant S uptake is unknown. We applied 14 C-, 35 S-, 13 C-, and 15 N-labelled cysteine to wheat and oilseed rape rhizospheres and traced the plants’ elemental uptake. Both plants absorbed 0.37–0.81% of intact cysteine after 6 h with no further increase after 24 h. They absorbed 1.6–11.5% 35 S and 12.3–7.6% 15 N from cysteine after 24 h and utilised SO 4 2− as their main S source (75.5–86.4%). Added and naturally occurring cysteine-S contributed 5.6 and 1.1% of total S uptake by wheat and oilseed rape, respectively. Cysteine and inorganic S derived from cysteine contributed 24.5 and 13.6% of uptake for wheat and oilseed rape, respectively, after 24 h. Oilseed rape absorbed ~10-fold more S from cysteine and SO 4 2− than did wheat. The highest absorption of free cysteine should be in the organic-rich soil patches. Soil microorganisms rapidly decomposed cysteine (t 1/2 = 1.37 h), and roots absorbed mineralised inorganic N and S. After 15 min, 11.7–14.3% of the 35 S-cysteine was retained in the microbial biomass, while 30.2–36.7% of the SO 4 2− was released, suggesting that rapid microbial S immobilisation occurs after cysteine addition. Plants acquire N and S from cysteine via unidirectional soil-to-root nutrient flow, and cysteine is an important S source for plants.

Ecological thresholds, which represent points of rapid change in ecological properties, are of major scientific and societal concern. However, very little research has focused on empirically testing the occurrence of thresholds in temperate terrestrial ecosystems. To address this knowledge gap, we tested whether a number of biodiversity, ecosystem functions and ecosystem condition metrics exhibited thresholds in response to a gradient of forest dieback, measured as changes in basal area of living trees relative to areas that lacked recent dieback. The gradient of dieback was sampled using 12 replicate study areas in a temperate forest ecosystem. Our results provide novel evidence of several thresholds in biodiversity (namely species richness of ectomycorrhizal fungi, epiphytic lichen and ground flora); for ecological condition (e.g. sward height, palatable seedling abundance) and a single threshold for ecosystem function (i.e. soil respiration rate). Mechanisms for these thresholds are explored. As climate-induced forest dieback is increasing worldwide, both in scale and speed, these results imply that threshold responses may become increasingly widespread.

Plant sulphur (S) deficiency occurs worldwide; however, in comparison to other macronutrients (e.g.,&nbsp;N, P), limited attention has been paid to the