Effects of nitrogen with and without acidified sulphur on an ectomycorrhizal community in a Sitka spruce (Picea sitchensis Bong. Carr) forest

This preliminary study investigated the effects of enhanced nitrogen (NH4NO3 at 48 kg ha(-1) y(-1)), sulphur (Na2SO4 at 50 kg ha(-1) y(-1)), acidified nitrogen and sulphur (H2SO4 + NH4NO3) at pre-stated doses (pH 2.5), and acidified nitrogen and sulphur deposition at double these doses on the ectomycorrhizal community associated with a 13-year-old Sitka spruce (Picea sitchensis) forest. Sulphur deposition had little impact on below ground ectomycorrhizal diversity, but stimulated sporocarp production. Nitrogen inputs increased below ground colonisation compared to acidified nitrogen and sulphur, largely due to an increase in Tylospora fibrillosa colonisation. Sporocarp production and ectomycorrhizal root colonisation by Lactarius rufus were reduced in the nitrogen treated plots. These observations suggest that nitrogen deposition to a young plantation may suppress ectomycorrhizal fungi producing large sporocarps. It is proposed that enhanced nitrogen deposition increases ectomycorrhizal nitrogen assimilation, consuming more carbon and leaving less for extrametrical mycelium and sporocarp development.     

Pragmatic estimation of a spatio-temporal air quality model with irregular monitoring data

Statistical analyses of health effects of air pollution have increasingly used GIS-based covariates for prediction of ambient air quality in “land use” regression models. More recently these spatial regression models have accounted for spatial correlation structure in combining monitoring data with land use covariates. We present a flexible spatio-temporal modeling framework and pragmatic, multi-step estimation procedure that accommodates essentially arbitrary patterns of missing data with respect to an ideally complete space by time matrix of observations on a network of monitoring sites. The methodology incorporates a model for smooth temporal trends with coefficients varying in space according to Partial Least Squares regressions on a large set of geographic covariates and nonstationary modeling of spatio-temporal residuals from these regressions. This work was developed to provide spatial point predictions of PM_2.5 concentrations for the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) using irregular monitoring data derived from the AQS regulatory monitoring network and supplemental short-time scale monitoring campaigns conducted to better predict intra-urban variation in air quality. We demonstrate the interpretation and accuracy of this methodology in modeling data from 2000 through 2006 in six U.S. metropolitan areas and establish a basis for likelihood-based estimation.     

Early Effects of Atmospheric Ammonia Deposition on Calluna Vulgaris (L.) Hull Growing on an Ombrotrophic Peat Bog

This paper reports data from a field study investigating the impacts of elevated ammonia (NH₃) deposition on Calluna vulgaris growing on an ombrotrophic peat bog in S.E. Scotland. Shoot extension, foliar N concentrations, chlorophyll concentration and chlorophyll fluorescence were measured during the second growing season of exposure to a gradient of ammonia concentrations. Results indicate that NH₃ increases growth between 150–200 kg N ha^–1y^–1 cumulative deposition. Foliar N content increased significantly in response to NH₃ cumulative deposition up to 400 kg N ha^–1 y^–1 whereas chlorophyll a content significantly decreased. Measurements of Fv/Fm suggest that although NH₃ exposure altered the growth and reduced chlorophyll a, the efficiency of photosystem II was insensitive to NH₃-N deposition at this stage.     

Bridging the gap: bringing together intentional and unintentional injury prevention efforts to improve health and well being

PROBLEM: Intentional and unintentional injury prevention efforts have traditionally been independent and non-integrated. Fostering collaboration between the sub-fields would enhance work within both sub-fields and advance injury prevention work as a whole. METHOD: A systematic assessment of similarities and differences between the sub-fields was performed, including an examination of relevant definitions and norms, research methods and findings, key risk and resiliency factors, and prevention strategies that would promote collaboration and better advance current prevention efforts. RESULTS/SUMMARY: Several areas exist in which injury prevention efforts could be coordinated or ideas and practices could be cross-applied, including training of practitioners, data collection and analysis, application of tools and methodologies, examination of risk and resiliency factors, and identification of funding sources and partners. IMPACT ON INDUSTRY: This paper delineates how intentional and unintentional injury prevention practitioners can more effectively collaborate to promote safer environments and further reduce incidence of injury. An integrated injury prevention approach could significantly impact the underlying contributors to both types of injury, allowing practitioners within both sub-fields to achieve greater outcomes through increased credibility, reduced duplication of efforts, more efficient use of resources, and unified injury prevention messages.     

An index of radioecology,what has been important?

The Journal of Environmental Radioactivity (JER) has been published for the last 20 years, an important time frame for the discipline of radioecology. Certainly the study of radioecology accelerated following the Chernobyl incident. As the discipline moves forward, there will be less emphasis on that incident, and scientists will find a new focus. Issues related to waste management and decommissioning may come to the fore. There is also a large effort world-wide to deal more quantitatively with the estimation of dose and consequences to non-human biota. All researchers in radioecology will have opinions on what topics are important now and will be important in the future. Indeed, Policy Board members and Associate Editors of JER have provided a number of Editorials in the Millennium Editorial Series with their perspectives. This paper explores the trends among papers published in JER since 1995, using the ScienceDirect on-line search capability to objectively categorize the papers and quantify the relative numbers of contributions. Obviously, this is somewhat imperfect, but it does provide an index of what has been important in radioecology, and provides some quantification to recent statements about the future of radioecology.     

High-impact conservation: invasive mammal eradications from the islands of western México

Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21,615 per colony and USD 49,370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in Mexico and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western Mexico provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.     

Quantifying dry NH3 deposition to an ombrotrophic bog from an automated NH3 field release system

Providing an accurate estimate of the dry component of N deposition to low N background, semi-natural habitats, such as bogs and upland moors dominated by Calluna vulgaris is difficult, but essential to relate nitrogen deposition to effects in these communities. To quantify the effects of NH₃ inputs to moorland vegetation growing on a bog at a field scale, a field release NH₃ fumigation system was established at Whim Moss (Scottish Borders) in 2002. Gaseous NH₃ from a line source was released along of a 60 m transect, when meteorological conditions (wind speed >2.5 m s^–1 and wind direction in the sector 180–215°) were met, thereby providing a profile of decreasing NH₃ concentration with distance from the source. In a complementary study, using a NH₃ flux chamber system, the relationships between NH₃ concentrations and cuticular resistances were quantified for a range of NH₃ concentrations and micrometeorological conditions for moorland vegetation. Cuticular resistances increased with NH₃ concentration from 11 s m^–1 at 3.0 g m^–3 to 30 s m^–1 at 30 g m^–3. The NH₃ concentration data and the concentration-dependent canopy resistance are used to calculate NH₃ deposition taking into account leaf surface wetness. The implications of using an NH₃ concentration-dependent cuticular resistance and the importance for refining critical loads are discussed.     

An Automated Wet Deposition System to Compare the Effects of Reduced and Oxidised N on Ombrotrophic Bog Species: Practical Considerations

Critical N loads for ombrotrophic bogs, which often contain rare and N-sensitive plants (especially those in lower plant groups: lichens, mosses and liverworts), are based on very few experimental data from measured, low background N deposition areas. Additionally the relative effects of reduced versus oxidised N are largely unknown. This paper describes an automated field exposure system (30 km S. of Edinburgh, Scotland) for treating ombrotrophic bog vegetation with fine droplets of oxidised N (NaNO₃) and reduced N (NH₄Cl). Whim Moss exists in an area of low ambient N deposition (ca. 8 kg N ha^–1 y^–1), the sources and quantification of which are described. The wet N treatment system is run continuously, and is controlled/activated by wind speed and rainfall to provide a unique simulation of real world treatment patterns (no rain=no treatment). Simulated precipitation is supplied at ionic concentrations below4mMin rainwater collected on site. Treatments provide a replicated dose response to 16, 32 and 64 kg N ha^–1 y^–1 adjusted for ambient deposition (8 kg N ha^–1 y^–1). The 16 and 64 kg N ha^–1 y^–1 are duplicated with a P+K supplement. Baseline soil chemistry and foliar nutrient status was established for all 44 plots for Calluna vulgaris, Sphagnum capillifolium, Hypnum jutlandicum and Cladonia portentosa.     

Spatial patterns of tungsten and cobalt in surface dust of Fallon,Nevada

Spatial patterns of tungsten and cobalt are described for surface dust of Fallon, Nevada, where a cluster of childhood leukemia has been ongoing since 1997. In earlier research, airborne tungsten and cobalt was shown to be elevated in total suspended particulates in Fallon. To fine-tune the spatial patterns of tungsten and cobalt deposition in Fallon, surface dust was collected in a grid pattern within as well as outside of Fallon to establish background concentrations of metals. In surface dust, tungsten and cobalt show sharp peaks (934 ppm and 98 ppm, respectively) within Fallon just north of highway 50 and west of highway 95. These two peaks overlap spatially, and given the grid pattern used for collecting surface dust, the source area of these two airborne metals can be pinpointed to the vicinity of hard-metal industry located north of highway 50 and west of highway 95. Fallon is distinctive in west central Nevada because of high airborne tungsten and cobalt particulates, and given its cluster of childhood leukemia, it stands to reason that additional biomedical research is in order to test directly the leukogenicity of combined airborne tungsten and cobalt particulates.     

Primordial radionuclides in Canadian background sites: secular equilibrium and isotopic differences

A literature review and field sampling were done to obtain information on primordial (natural-series) radionuclide concentrations in terrestrial environments in diverse locations across Canada. Of special interest was the degree of secular equilibrium among members of decay series. The analytes measured in soils and plants were (nat)U by neutron activation-delayed neutron counting, (228)Th, (230)Th, (232)Th, (226)Ra and (210)Po by alpha spectroscopy, (210)Pb by gas flow proportional counting, (228)Ra by beta counting and (137)Cs by gamma spectroscopy. In addition, ICP-MS was used to obtain concentrations of about 50 analytes including elemental U, Pb, and Th. Samples were from seven representative background sites with a total of 162 plant samples from 38 different species. These data were supplemented by a review that gathered a large portion of the similar data from published sources. The sites chosen were semi-natural, far from any nuclear industry, although several were specifically located in areas with slightly elevated natural U concentrations. As might be expected, there were many cases of non-detectable concentrations. However, certain trends were evident. The activity ratio (210)Po/(210)Pb was unity in soils and non-annual plant tissues such as lichens. It was about 0.6 in annual plant tissues. These results are consistent with the time required for ingrowth of (210)Po to reach secular equilibrium. There was evidence from several sources that (210)Pb in plants came predominantly from deposition of (210)Pb from air after the decay of airborne (222)Rn. This was expected. Somewhat unexpected was the observation that (228)Th seemed to be much more plant available than (232)Th, even though both are in the same decay series and should be chemically similar. The difference was attributed to the combined effects of ingrowth from (228)Ra in the plant and effects of alpha recoil in mobilizing (228)Th in the soil. In general, the results of this study will benefit risk assessment, both in providing background concentrations, but also some indication of where isotope activity ratios can and cannot be used to estimate concentrations.