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•We profiled the faecal microbial communities of horses with cyathostomin infections, pre- and post-anthelmintic treatment.•Methanomicrobia and Dehalobacterium were expanded in the ...microbiota of horses with low cyathostomin faecal egg counts.•A reduction in TM7 and an expansion in Adlercreutzia followed anthelmintic treatment in horses with high faecal egg counts.•Novel intervention strategies against cyathostomins based on the manipulation of the gut flora may be developed.
A growing body of evidence, particularly in humans and rodents, supports the existence of a complex network of interactions occurring between gastrointestinal (GI) helminth parasites and the gut commensal bacteria, with substantial effects on both host immunity and metabolic potential. However, little is known of the fundamental biology of such interactions in other animal species; nonetheless, given the considerable economic losses associated with GI parasites, particularly in livestock and equines, as well as the global threat of emerging anthelmintic resistance, further explorations of the complexities of host-helminth-microbiota interactions in these species are needed. This study characterises the composition of the equine gut commensal flora associated with the presence, in faecal samples, of low (Clow) and high (Chigh) numbers of eggs of an important group of GI parasites (i.e. the cyathostomins), prior to and following anthelmintic treatment. High-throughput sequencing of bacterial 16S rRNA amplicons and associated bioinformatics and statistical analyses of sequence data revealed strong clustering according to faecal egg counts (P = 0.003). A trend towards increased populations of Methanomicrobia (class) and Dehalobacterium (genus) was observed in Clow in comparison with Chigh. Anthelmintic treatment in Chigh was associated with a significant reduction of the bacterial Phylum TM7 14 days post-ivermectin administration, as well as a transient expansion of Adlercreutzia spp. at 2 days post-treatment. This study provides a first known insight into the discovery of the intimate mechanisms governing host-parasite-microbiota interactions in equines, and sets a basis for the development of novel, biology-based intervention strategies against equine GI helminths based on the manipulation of the commensal gut flora.
In recent years there has been increasing recognition of the need to include sediment control strategies within catchment management plans. Information on the source of the sediment transported by a ...river is an important requirement for designing effective sediment control strategies. This paper uses the source fingerprinting approach to establish suspended sediment sources within two small (<4
km
2) lowland agricultural catchments in the UK, which are both extensively under drained. Representative samples of suspended sediment were collected from both catchments to encompass the expected inter- and intra-storm variability in sediment source. Statistically verified composite fingerprints and multivariate mixing models, incorporating particle size correction factors, were used to estimate the relative contribution of the potential sediment sources. These included surface sources (classified by land use, geology and soil type), eroding channel banks and field drains (subsurface sources). Field drains were shown to be important suspended sediment sources in both catchments, accounting for 27–55% of the sediment yields. Bank erosion contributes ca. 10% or less of the sediment yields. Surface sources were found to be important in both catchments contributing between 34–65% of the sediment yield. The above estimates of the relative contribution of the individual sediment sources within the study catchments to the overall sediment yield were shown to conceal significant inter- and intra-storm variability in the source contributions.
Diffuse water pollution from agriculture (DWPA) is a major environmental concern, with significant adverse impacts on both human and ecosystem health. However, without an appropriate understanding of ...the multiple factors impacting on water, mitigation measures cannot be targeted. Therefore, this paper addresses this gap in understanding, reporting the hydrochemical monitoring evidence collected from the UK Government's Demonstration Test Catchments (DTC) programme including contrasting chalk and clay/mudstone catchments. We use data collected at daily and sub-daily frequency over multiple sites to address: (1) How does the behaviour of the full range of nitrogen (N) species and phosphorus (P) fractions vary? (2) How do N species and P fractions vary inter- and intra-annually? (3) What do these data indicate about the primary pollution sources? And (4) which diffuse pollution mitigation measures are appropriate in our study landscapes?
Key differences in the rates of flux of nutrients were identified, dependent on catchment characteristics. Full N speciation and P fractionation, together with dissolved organic carbon (DOC) enabled identification of the most likely contributing sources in each catchment. Nitrate (NO3-N) was the dominant N fraction in the chalk whereas organic and particulate N comprised the majority of the load in the clay/mudstone catchments. Despite current legislation, orthophosphate (PO4-P) was not found to be the dominant form of P in any of the catchments monitored. The chalk sub-catchments had the largest proportion of inorganic/dissolved organic P (DOP), accompanied by episodic delivery of particulate P (PP). Contrastingly, the clay/mudstone sub-catchments loads were dominated by PP and DOP. Thus, our results show that by monitoring both the inorganic and organic fractions a more complete picture of catchment nutrient fluxes can be determined, and sources of pollution pin-pointed. Ultimately, policy and management to bring nutrient impacts under control will only be successful if a multi-stressor approach is adopted.
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•N speciation and P fractionation analysed for catchments with contrasting character.•Nitrate was the dominant N species in the chalk sub-catchments.•Organic and particulate N comprised the majority of the load in the clay rivers.•Orthophosphate was not found to be the dominant fraction in any of the catchments.•Particulate P was always an important P source, particularly in the clay catchments.
Variations in the concentration of determinands in rivers during storms often result in a hysteresis effect with different concentration during the rising and falling limb of the hydrograph. This is ...investigated here by measuring total phosphorus, particulate phosphorus and soluble reactive phosphorus at 3-h intervals at three points along the River Swale. Phosphorus concentration–discharge hysteresis from 10 storm events were quantified using an empirical model. The size and direction of the hysteresis loops were described by a response factor, and the slope of the loop quantified by a gradient constant. The modelled loops produced acceptable agreement with the field measurements. Hysteresis patterns for all phosphorus fractions changed markedly downstream, with predominantly anticlockwise trajectories in the upland moors (indicating a slow diffuse phosphorus delivery to the river) and clockwise in the intensively farmed lowland (indicating mobilisation of within-channel and riverbank phosphorus, and rapid inputs from field drains). The size of the hysteresis loops increased downstream, indicating an increased capacity for phosphorus storage and mobilisation within the lower catchment. During a succession of storms, lowland hysteresis loops decreased in magnitude, tending towards anticlockwise behaviour, indicating a depletion of mobile phosphorus from the river channel and margins. The modelling of hysteresis trajectories offers a convenient method of determining the relative contributions of diffuse and within-channel phosphorus sources.
This paper provides an overview of the impacts of rural land use on lowland streamwater phosphorus (P) and nitrogen (N) concentrations and P loads and sources in lowland streams. Based on weekly ...water quality monitoring, the impacts of agriculture on streamwater P and N hydrochemistry were examined along a gradient of rural–agricultural land use, by monitoring three sets of ‘paired’ (near-adjacent) rural headwater streams, draining catchments which are representative of the major geology, soil types and rural/agricultural land use types of large areas of lowland Britain. The magnitude and timing of P and N inputs were assessed and the load apportionment model (LAM) was applied to quantify ‘continuous’ (point) source and ‘flow-dependent’ (diffuse) source contributions of P to these headwater streams. The results show that intensive arable farming had only a comparatively small impact on streamwater total phosphorus (TP loads), with highly consistent stream diffuse-source TP yields of ca. 0.5
kg-P
ha
−1
year
−1 for the predominantly arable catchments with both clay and loam soils, compared with 0.4
kg-P
ha
−1
year
−1 for low agricultural intensity grassland/woodland on similar soil types. In contrast, intensive livestock farming on heavy clay soils resulted in dramatically higher stream diffuse-source TP yields of 2
kg-P
ha
−1
year
−1. The streamwater hydrochemistry of the livestock-dominated catchment was characterised by high concentrations of organic P, C and N fractions, associated with manure and slurry sources. Across the study sites, the impacts of human settlement were clearly identifiable with effluent inputs from septic tanks and sewage treatment works resulting in large-scale increases in soluble reactive phosphorus (SRP) loads and concentrations. At sites heavily impacted by rural settlements, SRP concentrations under baseflow conditions reached several hundred μg-P
L
−1. Load apportionment modelling demonstrated significant ‘point-source’ P inputs to the streams even where there were no sewage treatment works within the upstream catchment. This indicates that, even in sparsely populated rural headwater catchments, small settlements and even isolated groups of houses are sufficient to cause significant nutrient pollution and that septic tank systems serving these rural communities are actually operating as multiple point sources, rather than a diffuse input.
Sediment budgets have been established for two small (<4 km
2), lowland, agricultural catchments, by using
137Cs measurements, sediment source fingerprinting and more traditional monitoring ...techniques to quantify the individual components of the budget. The gross and net erosion rates for the fields on the catchment slopes were estimated using
137Cs measurements within selected fields, which encompassed a representative range of slope angles, slope lengths and land use. These estimates were extrapolated over the entire catchment, using a simple topographically driven soil erosion model (Terrain-Based GIS, TBGIS) superimposed on a DEM, to derive catchment average gross and net erosion rates. Suspended sediment yields were measured at the catchment outlets and sediment source fingerprinting techniques were used to establish the relative contributions from the catchment surface, subsurface tile drains and eroding channel banks to the sediment yields. In-channel and wetland storage were quantified using both direct measurements and
137Cs measurements. The sediment budgets established for the catchments highlighted the importance of subsurface tile drains as a pathway for sediment transfer, accounting for ca. 60% and 30% of the sediment output from the two catchments. Erosion from channel banks contributed ca. 10% and 6% of the sediment output from the two catchments. Although the suspended sediment yields from these catchments were considered high by UK standards (ca. 90 t km
−2 year
−1), the sediment delivery ratios ranged between 14% and 27%, indicating that a major proportion of the mobilised sediment was stored within the catchments. In-field and field-to-channel storage were shown to be of similar magnitude, but storage of sediment in the channel system and associated wetlands was relatively small, representing <5% of the annual suspended sediment yield.
Correct identification of P sources in rural watersheds is critical for the development of cost-effective measures to combat agriculturally-driven eutrophication. The chemical composition of various ...storm runoff types (field surface runoff, field drain outfalls, roads, farmyards, and septic tanks) and the receiving streams in three micro (<10 km2) watersheds of varying agricultural intensity were monitored over a 2-yr period. Mean weekly stream soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations increased from 29 and 69 μg L-1, respectively in the watershed with the lowest intensity agriculture to 382 and 503 μg L-1, respectively in the watershed with high intensity agriculture and a village sewage treatment works. Concentrations of TP in storm runoff varied by up to two orders of magnitude reflecting the complex origins, routing, and composition of contributing source areas. Application of the DESPRAL test suggested field runoff TP concentrations were influenced by both P and organic matter in soil. However, runoff from impervious surfaces (farmyard and roads), and/or influenced by septic tank discharges, was significantly more concentrated (0.08-16 mg TP L-1, mean >>1 mg L-1) than surface and subsurface runoff from cultivated land and pasture (0.02-3.6 mg TP L-1, mean <1 mg L-1), and/or contained a significantly greater proportion (>50% vs. <50%) of P in dissolved forms. It is concluded that P sources associated with the functioning of rural communities (impervious surfaces, detergents, and wastewater) may be more ecologically relevant than those associated with agriculture and should be better quantified and controlled to avoid localized eutrophication impacts.
Characterization of phosphorus (P) sources in catchments is critical to the restoration of stream integrity following eutrophication. To better understand the effects of farming practices on P ...transfer in a small rural mixed farming catchment (Rosemaund), spatial and temporal patterns in P delivered from a field-drain (Foxbridge, 6
ha), and to two downstream stations (Jubilee, 31
ha and Belmont, 150
ha) were investigated in relation to detailed records on cultivation practices and fertilizer/manure P inputs over a 3-year period (1997–2000) with above-average rainfall. The Belmont catchment also included a farmstead and a small sewage treatment works (STW). The main source of P in drainflow (December–April) was the soil with flow-weighted concentrations of particulate P (PP) up to 2
mg
L
−1 and concentrations of dissolved-reactive P (DRP) (0.1–0.4
mg
DRP
L
−1) above current riverine targets to limit eutrophication. Agricultural operations carried out in autumn/early winter sporadically increased concentrations of DRP (fertilizer/manure applications) and PP (cultivations) in drain/stream discharge, but only during events that produced small amounts of stormflow. Occasionally large DRP and PP concentrations in drainflow were also recorded during the ecologically sensitive summer months, but this was unrelated to any farming practice. Stream P concentrations were further influenced by processes of baseflow dilution, in-stream retention/release and discharges from the STW and farmstead. The results highlight the disparity between the timing of farming operations at this site (autumn/early winter), the main period of land drainage (winter/spring) and the main period of biological activity (spring and summer). A greater understanding of the ecological significance of variably timed P inputs to headwater streams is needed to develop effective catchment management.
Abstract Objective To compare the responsiveness of the EuroQol five-dimensional questionnaire (EQ-5D) generic quality-of-life instrument with that of specific instruments—the Brief Pain Inventory ...(BPI) and the Oswestry Disability Index (ODI)—in assessing low back pain. Methods Data were obtained from a group of patients receiving epidural steroid injections. We assessed responsiveness by using correlation, by estimating standardized response means, by receiver operating characteristic curve analysis, and by comparing the minimum clinically important differences peculiar to each of the instruments. Results ODI, BPI, and EQ-5D index scores, and changes in scores, were found to be correlated. Estimated standardized response means and receiver operating characteristic curve analysis suggested lower responsiveness for the EQ-5D index score. Clinically significant categories of mild, moderate, and severe BPI pain intensity translated into progressively and significantly lower mean EQ-5D index scores. An increase or a decrease in severity level reported on any of the five EQ-5D dimensions was associated with significant changes (with appropriate signs) in the condition-specific scores. No change in severity in any EQ-5D dimension was associated with no change in the specific scores. Significant changes in the EQ-5D index scores were associated with clinically important changes in the ODI and BPI scores. Correlation between index scores and responses on EQ-5D’s visual analogue scale was only moderate. Conclusions The EQ-5D index is less responsive than instruments specific to pain measurement, although it is capable of indicating clinically important changes. The lower responsiveness arises from EQ-5D’s more limited gradation of severity and its multidimensionality.
Phosphorus dynamics along a river continuum Bowes, Michael J; House, William A; Hodgkinson, Robin A
The Science of the total environment,
09/2003, Letnik:
313, Številka:
1
Journal Article
Recenzirano
Changes in phosphorus concentration and form along 110 km of the River Swale in Northern England were examined over a 2-year period during 1998–2000. This study aimed to use these data to identify ...the importance of within-channel storage on phosphorus dynamics and to determine the changes in longitudinal transport of phosphorus along a river continuum. The catchment was divided into three contrasting zones: the upland, dominated by sheep farming; a transitional zone, and an intensively-farmed lowland, impacted by sewage inputs. Samples, taken at the downstream extent of each zone at approximately 2-day intervals, were analysed for total phosphorus (TP), total dissolved phosphorus (TDP) and soluble reactive phosphorus (SRP), all of which increased in concentration downstream. SRP concentrations were highest in summer and during low flows, although 92% of phosphorus was exported between autumn and spring. The TDP in the upper and transitional zones consisted of both soluble reactive and un-reactive phosphorus, but in marked contrast was almost entirely in soluble reactive form in the lowland. The majority (85%) of phosphorus exported from the catchment was generated within the lowland, due to sewage inputs and losses from intensive agricultural land. It was predominantly particulate-bound, due to interactions of dissolved phosphorus with suspended sediment. The upland contributed less than 5% to the TP annual budget. Intensive river water monitoring highlighted that the lowland dominated phosphorus export during the rising stage of storms (indicating a rapid mobilisation of fine phosphorus-rich sediment), whereas the transitional zone became dominant on the falling stage (due to greater diffuse phosphorus input).
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