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No abstract is provided for this article.

No abstract is provided for this article.

Nitrogen oxides (NOx = NO + NO2) are important atmospheric pollutants that are directly harmful to human health. Recently in urban and industrial areas, synthetic materials have been developed and deployed to photocatalytically oxidize NOx to nitrate (NO3-) in order to improve air quality. We show that the natural presence of small amounts (≤5%) of titanium oxides, such as anatase and rutile, can also drive NOx oxidation to nitrate in soils under UV-visible irradiation. The NO uptake coefficients ranged between 0.1 × 10-6 for sandy soils to 6.4 × 10-5 in the case of tropical clay soils; the latter comparable in efficiency to current industrial man-made catalysts. This photocatalytic N-fixation mechanism offers a new strategy for NOx mitigation from the atmosphere by transforming it into nitrate, and simultaneously provides an energy efficient source of essential fertilizer to agriculture.

Sustainability of bivalve shellfish farming relies on clean coastal waters, however, high levels of faecal indicator organisms (FIOs, e.g. Escherichia coli) in shellfish results in temporary closure of shellfish harvesting beds to protect human health, but with economic consequences for the shellfish industry. Active Management Systems which can predict FIO contamination may help reduce shellfishery closures. This study evaluated predictors of E. coli concentrations in two shellfish species, the blue mussel (Mytilus edulis) and the Pacific oyster (Crassostrea gigas), at different spatial and temporal scales, within 12 estuaries in England and Wales. We aimed to: (i) identify consistent catchment-scale or within-estuary predictors of elevated E. coli levels in shellfish, (ii) evaluate whether high river flows associated with rainfall events were a significant predictor of shellfish E. coli concentrations, and the time lag between these events and E. coli accumulation, and (iii) whether operation of Combined Sewer Overflows (CSO) is associated with higher E. coli concentrations in shellfish. A cross-catchment analysis gave a good predictive model for contamination management (R

Bivalve shellfish have the capacity to accumulate norovirus (NoV) from waters contaminated with human sewage. Consequently, shellfish represent a major vector for NoV entry into the human food chain, leading to gastrointestinal illness. Identification of areas suitable for the safe cultivation of shellfish requires an understanding of NoV behaviour upon discharge of sewage into coastal waters. This study exploited the potential of Mytilus edulis to accumulate NoV and employed the proposed international standard method for quantification of NoV within mussel digestive tissues. To evaluate the spatial and temporal spread of NoV from an offshore sewage discharge pipe, cages of mussels were suspended from moorings (n=13) deployed in a 1km grid array around the outfall. Caged mussels were retrieved after 30 days and NoV (GI and GII), coliforms and E. coli enumerated. The experimentally derived levels of NoV GI and GII in mussels were similar, with NoV spread from the outfall showing a distinct plume which matched very closely to a tidallydriven effluent dispersal model. A contrasting spatial pattern was observed for coliforms. These data demonstrate that coliform / E. coli concentrations do not accurately reflect viral dispersal in marine waters and contamination of shellfish by sewage-derived viral pathogens.

High-throughput sequencing 16S rRNA gene surveys have enabled new insights into the diversity of soil bacteria, and furthered understanding of the ecological drivers of abundances across landscapes. However, current analytical approaches are of limited use in formalizing syntheses of the ecological attributes of taxa discovered, because derived taxonomic units are typically unique to individual studies and sequence identification databases only characterize taxonomy. To address this, we used sequences obtained from a large nationwide soil survey (GB Countryside Survey, henceforth CS) to create a comprehensive soil specific 16S reference database, with coupled ecological information derived from survey metadata. Specifically, we modeled taxon responses to soil pH at the OTU level using hierarchical logistic regression (HOF) models, to provide information on both the shape of landscape scale pH-abundance responses, and pH optima (pH at which OTU abundance is maximal). We identify that most of the soil OTUs examined exhibited a non-flat relationship with soil pH. Further, the pH optima could not be generalized by broad taxonomy, highlighting the need for tools and databases synthesizing ecological traits at finer taxonomic resolution. We further demonstrate the utility of the database by testing against geographically dispersed query 16S datasets; evaluating efficacy by quantifying matches, and accuracy in predicting pH responses of query sequences from a separate large soil survey. We found that the CS database provided good coverage of dominant taxa; and that the taxa indicating soil pH in a query dataset corresponded with the pH classifications of top matches in the CS database. Furthermore we were able to predict query dataset community structure, using predicted abundances of dominant taxa based on query soil pH data and the HOF models of matched CS database taxa. The database with associated HOF model outputs is released as an online portal for querying single sequences of interest ( https://shiny-apps.ceh.ac.uk/ID-TaxER/ ), and flat files are made available for use in bioinformatic pipelines. The further development of advanced informatics infrastructures incorporating modeled ecological attributes along with new functional genomic information will likely facilitate large scale exploration and prediction of soil microbial functional biodiversity under current and future environmental change scenarios.

Protein represents a major input of organic matter to soil and is an important source of carbon (C) and nitrogen (N) for microorganisms. Therefore, determining which soil properties influence protein mineralisation in soil is key to understanding and modelling soil C and N cycling. However, the effect of different soil properties on protein mineralisation, and especially the interactions between soil properties, are poorly understood. We investigated how topsoil and subsoil properties affect protein mineralisation along a grassland altitudinal (catena) sequence that contained a gradient in soil type and primary productivity. We devised a schematic diagram to test the key edaphic factors that may influence protein mineralisation in soil (e.g. pH, microbial biomass, inorganic and organic N availability, enzyme activity and sorption). We then measured the mineralisation rate of 14C-labelled soluble plant-derived protein and amino acids in soil over a two-month period. Correlation analysis was used to determine the associations between rates of protein mineralisation and soil properties. Contrary to expectation, we found that protein mineralisation rate was nearly as fast as for amino acid turnover. We ascribe this rapid protein turnover to the low levels of protein used here, its soluble nature, a high degree of functional redundancy in the microbial community and microbial enzyme adaptation to their ecological niche. Unlike other key soil N processes (e.g. nitrification, denitrification), protease activity was not regulated by a small range of factors, but rather appeared to be affected by a wide range of interacting factors whose importance was dependent on altitude and soil depth [e.g. above-ground net primary productivity (NPP), soil pH, nitrate, cation exchange capacity (CEC), C:N ratio]. Based on our results, we hypothesise that differences in soil N cycling and the generation of ammonium are more related to the rate of protein supply rather than limitations in protease activity and protein turnover per se.

Dissolved organic carbon (DOC) turnover in aquatic environments is modulated by the presence of other key macronutrients, including nitrogen (N) and phosphorus (P). The ratio of these nutrients directly affects the rates of microbial growth and nutrient processing in the natural environment. The aim of this study was to investigate how labile DOC metabolism responds to changes in nutrient stoichiometry using 14C tracers in conjunction with untargeted analysis of the primary metabolome in upland peat river sediments. N addition led to an increase in 14C-glucose uptake, indicating that the sediments were likely to be primarily N limited. The mineralisation of glucose to 14CO2 reduced following N addition, indicating that nutrient addition induced shifts in internal carbon (C) partitioning and microbial C use efficiency (CUE). This is directly supported by the metabolomic profile data which identified significant differences in 22 known metabolites (34% of the total) and 30 unknown metabolites (16% of the total) upon the addition of either N or P. 14C-glucose addition increased the production of organic acids known to be involved in mineral P dissolution (e.g. gluconic acid, malic acid). Conversely, when N was not added, the addition of glucose led to the production of the sugar alcohols, mannitol and sorbitol, which are well known microbial C storage compounds. P addition resulted in increased levels of several amino acids (e.g. alanine, glycine) which may reflect greater rates of microbial growth or the P requirement for coenzymes required for amino acid synthesis. We conclude that inorganic nutrient enrichment in addition to labile C inputs has the potential to substantially alter in-stream biogeochemical cycling in oligotrophic freshwaters.

Sulphur-containing amino acids (i.e. Cysteine (Cys) and methionine (Met)) constitute an important proportion of the soil organic sulphur. However, detailed information regarding the microbial transformation of Cys and Met at a molecular level remain poorly characterized. To trace the fate of carbon (C) and sulphur (S) derived from Cys and Met in an agricultural grassland soil, a14C and 35S dual-isotopic labelling approach was adopted. We also investigated whether their mineralization was affected by manipulating C (added as glucose), nitrogen (N), phosphorus (P) and S (added as NH4NO3, KH2PO4 and K2SO4) availability in soil solution. Our results showed that over a 7-day incubation period, 67.2–89.2% of the 14C derived from Cys and Met was respired as 14CO2, 2.7–19.5% had been immobilized in the soil microbial biomass; while the recovery of 35S in soil solution ranged from 6.4 to 9.9%, with the reminder retained in the soil microbial biomass. Overall, our results indicated that soil microbial communities possess a high capacity to utilize Cys and Met. Furthermore, using the 14C and 35S dual-labelling technique, we found that C and S derived from Cys and Met were microbially mineralized and immobilized at different rates, indicating that the cycles of these two elements were temporally decoupled at the molecular level. The addition of glucose-C increased 14CO2 respiration from Cys and Met after 7 d, while in comparison inorganic N, P and S addition had less effect on 14C and 35S partitioning.

We report on ecological restoration at Penrhyn, Europe's largest slate quarry, which lies adjacent to Snowdonia National Park and a Site of Special Scientific Interest. Broadleaf woodland and heathland were targeted, to provide wildlife corridors to adjacent habitats of high conservation value. Young tree seedlings (six species) of local provenance were planted into slate pockets amended with nutrients (readily available mineral NPK or an organic mix of biosolids and paper sludge with an estimated five-year impact) and water retentive materials (clay overburden or polyacrylamide gel). Applying mineral NPK increased tree basal area by 70% in the first 18 months. The organic mix gave an increase of 130 % in tree basal area, promoted water retention and stimulated nutrient cycling. Both N-fixing tree species and non-fixers responded to fertilization and small-seeded species responded more than large-seeded ones. Tree basal area increased by 50% in the clay treatment compared with trees planted in bare slate ± gel. The transfer during quarrying of heath vegetation with associated peat to a site designated for restoration proved effective in establishing key heathland subshrubs. Bilberry re-sprouted easily from buried shoots whilst heather turf died, but within one year a flush of heather seedlings had germinated from the seedbank in the transferred peat. Three years on, there was complete ground cover of target heathland species, provided that sheep were excluded. Grazing by rabbits was beneficial in reducing grass and increasing heather cover. Where availability of heathland topsoil was limited, heathland brash was applied to clay-covered slate. Germination of heather proved slow and sparse, with no germination of bilberry.

Long -term herbaceous response data following herbicidal treatment of honey mesquite (Prosopis glandulosa Torr.) are needed to develop more accurate projections regarding economic feasibility of these treatments and to model ecological interactions between woody and herbaceous plants in rangeland sys- tems.Our objective was to measure herbaceous yield and mesquite regrowth 10 or 20 years after mesquite was aerially sprayed with either mesquite top -killing or root -killing herbicides.Treatments evaluated included mesquite top -killing herbicides at 10 -12 years (T10) and 19 -21 years (T20) post-treatment, mesquite root -killing herbicides at 10 -12 years (R10) and 19 -21 years (R20) post-treatment, and an untreated control where mesquite were >30 years old (C30).Treatments were applied in the late 1970's or late 1980's.Grass yields, measured annually from 1998 through 2000, were quantified within patches of 3 perennial grass functional groups: cool -season mid -grasses, warm -season mid -grasses, or warm -season short -grasses.Coolseason annual grass yields were also quantified within these perennial grass patches.By 1998, mesquite canopy cover was 55, 47, 36, 24, and 12% in C30, T20, T10, R20, and R10 treatments, respectively.Warm-season mid -grass yields were most sensitive to differences in mesquite cover in all 3 years and declined sharply when mesquite cover exceeded 30 %. Cool-season midgrass yields declined slightly with increasing mesquite cover.Warm-season short -grass and cool-season annual grass yields were not related to mesquite cover, except in 2000 when warmseason short -grass yield beneath mesquite canopies increased with increasing mesquite cover.Results suggest that herbicide treatment life (defined by increased perennial grass yield in response to mesquite treatments) was at least 20 years for the root -killing herbicide, but no longer than 10 years for the topkilling herbicide.

Escherichia coli are often used as faecal indicator bacteria (FIB) to provide a measure of microbial pollution in recreational and shellfish harvesting waters. However, although model forecasts for predicting the concentrations of FIB in surface waters are becoming more robust, they suffer from an inconsistency in quantification methods and an understanding of the spatial variation of FIB within a water course. The aim of this study was to investigate the transverse spatial variation in E. coli numbers (as an indicator of faecal pollution) across the estuary of the River Conwy, UK. Water samples were collected from four transverse transects across the estuary. Spatial variation of E. coli was significantly different from one side of the river to the other, although was not correlated with depth or the physiochemical properties of the water. Subsequently, microbial water quality classifications on the two opposite banks suggested very different levels of pollution coming down the river. This work has shown that the side of the river that routine water monitoring samples are taken from can make a significant difference to the classification of microbial water quality. This has important implications for sampling strategies and the use of microbial source tracking (MST) techniques.