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Soil erosion is considered the biggest contributor to nonpoint source pollution in the United States according to the U.S. Environmental Protection Agency and the federally mandated National Pollution Discharge Elimination System. Soil loss rates from construction sites can be 10 to 20 times that of agricultural lands. The use of surface applied organic amendments has been shown to reduce runoff and erosion, however, with the exception of animal manure, little research has focused on nutrient loss from these amendments. Four types of compost blankets, hydroseed, silt fence, and a bare soil (control) were applied in field test plots. Treatments were seeded with common bermuda grass. A rainfall simulator applied rainfall at an average rate equivalent to a 50 yr hr −1 storm event (7.75 cm hr −1 ). Three simulated rain events were conducted: immediately after treatment application, at three months when vegetation was established, and at one year when the vegetation was mature. After three months, the compost generated five times less runoff than hydroseed with silt fence, and after one year, generated 24 percent less runoff. All treatments proved better than the control at reducing solids loss. Total solid loads were as much as 3.5 times greater from hydroseed and silt fence compared to the composts during the first storm, and as much as 16 times greater during the second storm. Materials high in inorganic nitrogen (N) released greater amounts of nitrogen in storm runoff; however, these materials showed reduced N loss over time. Hydroseeding generated significantly higher total phosphorus (P) and dissolved reactive P loads compared to compost in storm runoff during the first storm event.

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements.

The significance of biodiversity to biogeochemical cycling is viewed most directly through the specific biogeochemical transformations that organisms perform. Although functional diversity in soils can be great, it is exceeded to a high degree by the richness of soil species. It is generally inferred from this richness that soil systems have a high level of functional redundancy. As such, indices of species richness probably contribute little to understanding the functioning of soil ecosystems. Another approach stresses the value of identifying \"keystone\" organisms, that is those that play an exceptionally important role in determining the structure and function of ecosystems. Both views tend to ignore the importance of biodiversity in maintaining the numerous and complex interactions among organisms in soils and their contributions to biogeochemical cycling. We describe some of those interactions and their importance to ecosystem function. Soil organisms alter the physical, chemical and biological properties of soils in innumerable ways. The composition and structure of biotic communities at one hierarchical level can influence the spatial heterogeneity of resource and refuge patches at other hierarchical levels. This spatial heterogeneity is supported by a number of biologically relevant spheres of influence that include the detritusphere, the drilosphere, the porosphere, the aggregatusphere and the rhizosphere. Each has fairly distinct properties that operate at different spatial scales. We discuss how these properties may function in regulating the interactions among organisms and the biogeochemical processes that they mediate. It is through the formation of a spatially and temporally heterogeneous structure that biodiversity may contribute most significantly to the functioning of soil ecosystems. Real advances in understanding the significance of biodiversity to biogeochemical cycling will come from taking a broader view of biodiversity. Such a view will necessarily encompass many levels of resolution including: 1) the importance of biodiversity to specific biogenic transformations, 2) the complexity and specificity of biotic interactions in soils that regulate biogeochemical cycling, and 3) how biodiversity may operate at different hierarchically arranged spatial and temporal scales to influence the structure and function of ecosystems.

Soil erosion is one of the biggest contributors to nonpoint source pollution in the United States. Soil loss rates from construction sites are 10 to 20 times that of agricultural lands. The use of surface applied organic amendments has been shown to reduce runoff and erosion through enhanced vegetation growth and soil quality characteristics. The objective of this study was to evaluate the vegetation growth and soil quality effects from compost blanket and hydroseed applications to soils disturbed by construction activities. Four types of compost blankets, two hydroseeded treatments (silt fence and mulch filter berm) and a bare soil (control) were applied in field test plots. Treatments were seeded with common Bermuda grass ( Cynodon dactylon ). Vegetative growth (percent cover and biomass of weeds and grasses) and soil quality characteristics were evaluated periodically over one year and 18 months, respectively. Results showed compost blankets provided an average of 2.75 times more vegetative cover than hydroseed after three months. After one year, cover was similar, but hydroseed had significantly greater weed biomass than compost and a greater ratio of weed biomass relative to Bermuda grass biomass. One type of compost blanket increased surface soil extractable organic carbon, and another type increased organic matter in 0 to15 cm (0 to 6 in) soil depths relative to hydroseed treated soils. A one-time application of hydroseed that included mineral phosphorus (P) fertilizer elevated surface soil P after 18 months. On construction sites where disturbed soils are prone to erosion and vegetation establishment is required, compost applications will promote quicker vegetation cover with less weed growth than hydroseeding. Some compost erosion control blankets have the ability to increase soil quality characteristics relative to hydroseed applications within 18 months of application.

Background : APECED (Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy) is a rare autosomal recessive disease characterised primarily by sequential immune-mediated destruction of endocrine tissues, chronic oral or mucocutaneous candidiasis and ectodermal disorders, including hypoplasia of dental enamel. Aim : This was to investigate the oral health and presence of enamel defects in a cohort of patients with APECED. Methods : 16 patients with APECED (mean age of 13.9 years) were matched for age and gender with healthy controls. A comprehensive medical, dental and drug history was recorded, followed by a clinical assessment of oral health which was determined by assessing periodontal treatment needs, prevalence of dental caries, erosion, fluorosis and enamel defects. The estimated time of the development of the enamel defects and the contemporaneous medical diagnosis were recorded. Results : Oral health of patients with APECED was poor compared with controls, with a higher prevalence of periodontal disease, caries and erosion. There was a significantly (P < 0.05) higher prevalence of enamel defects in the study group. The enamel defects were mostly hypoplastic in the form of pits, missing enamel and grooves. The enamel defects occurred in a chronological pattern. There was a strong association between the estimated time of defective enamel formation and a history of hypoparathyroidism. Gastrointestinal dysfunction and a history of chronic mucocutaneous candidiasis were also associated with the presence of enamel defects. Conclusion : The oral health of individuals with APECED was poor compared with controls with a higher prevalence of periodontal disease, caries, erosion and enamel defects. The enamel defects in the study population occurred in a chronological pattern and some were associated with a history of systemic disease during the period of tooth development.

We adapted a direct count method for obtaining counts of active protozoa that was not overly time consuming. Soil samples from an agricultural field were examined at 1- to 3-day intervals three times through the year. The three sampling periods represented different weather conditions. At each sampling event, fresh soil samples were extracted upon return to the laboratory for protozoa. These were enumerated at the microscope without prior culture, in soil-water suspension dilutions. We describe a procedure that allowed all samples to be processed in a few hours. Our results suggest there is good reproducibility and agreement between samples collected on the same day. Our data resolve differences between days as soil conditions changed slowly with drying or wetting. This procedure is suitable for describing species active at the time of sampling. Unlike the 'most probable number' procedure that relies on cultivable species, it is less prone to enumerating excysting individuals, and it provides better resolution between sampling dates, with a relatively low number of samples.[PUBLICATION ABSTRACT]

Wolters et al identify the basic types of interaction between vascular plants and soil biota, describe the sensitivity of each type to changes in species composition, and evaluate the potential consequences of global change drivers on ecosystem processes.

In the lower montane region of northwestern Ecuador, forest clearing for sugar cane and pasture production occurs simultaneously with recolonization of secondary forest vegetation on abandoned agricultural lands. We estimated the loss of forest-derived soil C (light in13C) and the accumulation of C from replicate sugar cane and pasture vegetation (heavy in13C) using a stable C isotope technique. We also measured differences in the proportion of soil C derived from C3and C4plants across a land-use progression from agricultural fields through successional communities and undisturbed forest. Total soil C was 23 Mg/ha lower in the upper 30 cm following 50 yr of sugar cane production (24% decrease) compared to old-growth forest. The net change (-0.4 Mg·ha-1·yr-1) in soil C consisted of 1.3 Mg/ha annual losses of original forest C and 0.9 Mg/ha annual gains of C from sugar cane. After 15 yr beneath pasture, soil C was 11 Mg/ha less in the upper 30 cm than beneath forest (12% decrease). During that period, 33% of the original forest C was lost, compared to 68% released during 50 yr of sugar cane cultivation. Rate of forest C loss, C4-C accumulation, and net soil C change differed little between two distinct pasture types. Setaria sphacelata pasture and a traditional mixed-species pasture both contained more total soil C and added C4-C more rapidly than sugar cane. Under second-growth forest, soil C increased by 1.9 Mg·ha-1·yr-1, the result of a 3 Mg/ha annual increase in C3carbon and a 1.1 Mg/ha annual loss of C4carbon. The total soil C pool returned to preclearing levels within 20 yr. While widespread reforestation may be thwarted by high demands for land in northwestern Ecuador, agricultural land-use options exist that can contribute to increased soil C stocks.

Since species loss is predicted to be nonrandom, it is important to understand the manner in which those species that we anticipate losing interact with other species to affect ecosystem function. We tested whether litter species diversity, measured as richness and composition, affects breakdown dynamics in a detritus-based stream. Using full-factorial analyses of single- and mixed-species leaf packs (15 possible combinations of four dominant litter species; red maple [Acer rubrum], tulip poplar [Liriodendron tulipifera], chestnut oak [Quercus prinus], and rhododendron [Rhododendron maximum]), we tested for single-species presence/absence (additive) or species interaction (nonadditive) effects on leaf pack breakdown rates, changes in litter chemistry, and microbial and macroinvertebrate biomass. Overall, we found significant nonadditive effects of litter species diversity on leaf pack breakdown rates, which were explained both by richness and composition. Leaf packs containing higher litter species richness had faster breakdown rates, and antagonistic effects of litter species composition were observed when any two or three of the four litter species were mixed. Less-consistent results were obtained with respect to changes in litter chemistry and microbial and macroinvertebrate biomass. Our results suggest that loss of litter species diversity will decrease species interactions involved in regulating ecosystem function. To that end, loss of species such as eastern hemlock (Tsuga canadensis) accompanied by predicted changes in riparian tree species composition in the southeastern United States could have nonadditive effects on litter breakdown at the landscape scale.

Population dynamics of enchytraeids are described for 2 montane forested watersheds in southwestern North Carolina (Coweeta) and an agricultural site under conventional (CT) and no-tillage (NT) management in the northeastern Georgia piedmont (Horseshoe Bend, HSB). Given that much of the taxonomy, ecology and community structure of enchytraeids is poorly known, our objective was to identify key \"indicators\" of enchytraeid community structure which could be used, in this case, to better understand their role in soil structure formation. Although population densities of enchytraeids were higher in the forested (Coweeta) than in the arable soils (HSB), the average ash free dry weight per enchytraeid at HSB was nearly double that found at Coweeta. Based on these measurements and an estimate of their gut transit time, we calculated that the enchytraeids at HSB transported 2180 g of soil per m² per year compared to 443 and 393 g m⁻² yr⁻¹ for watershed 18 and 27, respectively at Coweeta. We therefore hypothesize that enchytraeids have a larger influence on soil structure in agricultural fields than in forested areas, in spite of lower population densities. The ash free dry weight and ash wt. per enchytraeid may qualify as key \"indicator\" parameters of enchytraeid community structure which helps to understand their functional role in ecosystems, though more studies are called for.