Addressing the Impact of Atmospheric Nitrogen Deposition on Western European Grasslands

There is a growing evidence base demonstrating that atmospheric nitrogen deposition presents a threat to biodiversity and ecosystem function in acid grasslands in Western Europe. Here, we report the findings of a workshop held for European policy makers to assess the perceived importance of reactive nitrogen deposition for grassland conservation, identify areas for policy development in Europe and assess the potential for managing and mitigating the impacts of nitrogen deposition. The importance of nitrogen as a pollutant is already recognized in European legislation, but there is little emphasis in policy on the evaluation of changes in biodiversity due to nitrogen. We assess the potential value of using typical species, as defined in the European Union Habitats Directive, for determining the impact of nitrogen deposition on acid grasslands. Although some species could potentially be used as indicators of nitrogen deposition, many of the typical species do not respond strongly to nitrogen deposition and are unlikely to be useful for identifying impact on an individual site. We also discuss potential mitigation measures and novel ways in which emissions from agriculture could be reduced.     

Observations on the short-term movements and behaviour of whale sharks (Rhincodon typus) at Ningaloo Reef, Western Australia

The short-term movements and behaviour of whale sharks (Rhincodon typus Smith, 1828) during March 1994 and April 1997 are reported from data collected by acoustic tracking and archival tags at Ningaloo Reef on the north west coast of Western Australia. Sharks were tracked for up to 26 h and generally swam slowly at ≃0.7 m s⁻¹ parallel to the reef edge; occasionally they swam in a wide arc adjacent to passes in the reef. All tracked sharks made regular dives through the water column, mostly from the surface to near the bottom. These dives did not appear to be related to hydrographic features, and the sharks were probably searching the water column for food. Most sharks were accompanied by other fishes, usually the golden trevally Gnathanodon speciosus. Received: 19 January 1999 / Accepted: 22 June 1999     

Fate of 1,2,3,4,6,7,8-heptachlorodibenzofuran and pentachlorophenol during laboratory-scale anaerobic mesophilic sewage sludge digestion

The possibility of the formation of PCDDs and dechlorination of PCDFs during the anaerobic digestion of sewage sludge in laboratory scale digesters was investigated. Digesters were spiked with 1,2,3,4,6,7,8-HpCDF-13C(6) (240 ng/g organic matter (OM)) and pentachlorophenol (PeCP)-13C(6) (24 microg/g OM) and the output sludge monitored for 60 days. No dechlorination or formation of the labelled or native PCDD/Fs was observed. The detectable 1,2,3,4,6,7,8-HpCDF-13C(6) dechlorination yield was 0.0008-1% depending on homologue group and the detectable formation of OCDD yield was 0.00042% PeCP-13C(6). Preferential respiration of other, more bioavailable, substrates is suggested as the most plausible explanation for the lack of dechlorination. Formation of PCDDs from PeCP has been observed in aerobic environments but this study provides further evidence that it is not a precursor for formation during anaerobic digestion.     

Dissolved organic nitrogen regulation in freshwaters

Dissolved organic nitrogen (DON) has been hypothesized to play a major role in N cycling in a variety of ecosystems. Our aim was to assess the seasonal and concentration relationships between dissolved organic carbon (DOC), DON, and NO3- within 102 streams and 16 lakes within catchments of differing complexity situated in Wales. Further, we aimed to assess whether patterns of land use, soil type, and vegetation gave consistent trends in DON and dissolved inorganic nitrogen (DIN) relationships over a diverse range of catchments. Our results reinforce that DON constitutes a significant component of the total dissolved N pool typically representing 40 to 50% of the total N in streams and lakes but sometimes representing greater than 85% of the total dissolved N. Generally, the levels of DON were inversely correlated with the concentration of DIN. In contrast to DIN concentrations, which showed distinct seasonality, DON showed no consistent seasonal trend. We hypothesize that this reflects differences in the bioavailability of these two N types. The amount of DON, DOC, and DIN was significantly related to soil type with higher DON export from Histosol-dominated catchments in comparison with Spodosol-dominated watersheds. Vegetation cover also had a significant effect on DON concentrations independent of soil type with a nearly twofold decrease in DON export from forested catchments in comparison with nonforested watersheds. Due to the diversity in catchment DON behavior, we speculate that this will limit the adoption of DON as a broad-scale indicator of catchment condition for use in monitoring and assessment programs.     

On the potential of iPhone significant location data to characterize individual mobility for air pollution health studies

● We evaluated the accuracy of iPhone data in capturing time-activity patterns. ● iPhone data captured the most important microenvironments and time spent in them. ● iPhone data also accurately captured daily exposure to ambient PM pollution. ● A considerable fraction of the population in the USA may have iPhone data available. ● iPhone data has great potential in air pollution health studies. In many air pollution health studies, the time-activity pattern of individuals is often ignored largely due to lack of data. However, a better understanding of this location-based information is expected to decrease uncertainties in exposure estimation. Here, we showcase the potential of iPhone’s Significant Location (iSL) data in capturing the user’s historical time-activity patterns in order to estimate exposure to ambient air pollutants. In this study, one subject carried an iPhone in tandem with a reference GPS tracking device for one month. The GPS device recorded locations in 10 second intervals while the iSL recorded the time spent in locations the subject visited frequently. Using GPS data as a reference, we then evaluated the accuracy of iSL data in capturing the subject’s time-activity patterns and time-weighted air pollution concentration within the study time period. We found the iSL data accurately captured the time the subject spent in 16 microenvironments (i.e. locations the subject visited more than once), which was 93% of the time during the study period. The average error of time-weighted aerosol optical depth value, a surrogate of particle pollution, is only 0.012%. To explore the availability of iSL data among iPhone users, an online survey was conducted. Among the 349 surveyed participants, 72% of them have iSL data available. Considering the popularity of iPhones, iSL data may be available for a significant portion of the general population. Our results suggest iSL data have great potential for characterizing historical time-activity patterns to improve air pollution exposure estimation.     

Closing the gap: a research agenda to accelerate the adoption and effective use of proven older adult fall prevention strategies

IntroductionTo make an impact on the public's health, evidence-based interventions must be disseminated broadly, supported by training and technical assistance, adopted widely, and implemented as designed. Many effective older adult fall prevention interventions have been identified, but too few have gained wide community acceptance and little is known about the best ways to encourage their broader use. Therefore, as in many other fields, fall prevention suffers from a wide gap between scientific discoveries and their everyday use.MethodThis article articulates the key activities embedded in Step 4 of the public health model—specifically translation and dissemination to ensure widespread adoption and use—in order to illuminate critical research needs in older adult fall prevention.ConclusionsThese needs, if addressed, will help close the gap between research and practice.     

Repeatability of Phase 1 habitat survey

As the major part of a Habitat Survey of Wales, over 80% of the land surface was surveyed in the field between 1987 and 1997 using the Phase 1 method. A resurvey of 294 randomly selected points was carried out during the early stages to audit the quality of the data being collected, leading to the development of a set of recommendations for the surveyors to improve the consistency and accuracy of habitat mapping. Recent studies have indicated a high level of discrepancy between organisations in field habitat mapping using the Phase 1 method. The findings of the Phase 1 audit in Wales are presented here to show the level of repeatability that was achieved within an organisation. There was 76% correspondence in habitat mapping between 'surveyor' and 'assessor' at the level of individual Phase 1 habitat classes. The degree of repeatability varied according to habitat strata: it was highest for modified land cover types (88%), lowest for semi-improved types (56%) and intermediate for semi-natural types (75%). An overall estimate of the repeatability of Phase 1 survey in the study area of 83% was obtained by weighting the figures for the three strata by the proportion of land area occupied by each stratum. This figure increased to 85% when habitats were amalgamated into Broad Habitat groups. These results are considerably better than those reported by studies of consistency between organisations. Most of the discrepancies between surveyor and assessor were caused by differences in habitat identification. However, at almost two thirds of the points where such a difference occurred, the assessor noted that the vegetation was transitional or borderline with that mapped by the surveyor.     

Element content in tissues of four rodent species sampled in the Geysers geothermal steamfield

Liver and kidney tissue samples from four rodent species collected in the Geysers geothermal steamfield of northern California were analyzed for content of 28 elements. Element concentrations in samples from the developed region of the Geysers were compared with samples from undeveloped reference regions to determine the influence of geothermal power development on element content in small mammal tissues. Eight elements (B, Ca, Cu, Mg, Mn, P, Sr, Ti) were enriched in samples from the Geysers, 12 (Ag, Al, Co, Cr, Fe, K, Mo, Na, Ni, Pb, Si, Zn) were decreased within the Geysers, Ba and Li were inconclusive, and six (As, Be, Cd, Hg, Sn, V) were below the minimum analytical limits. The longest-lived species (Neotoma fuscipes) had the greatest occurrence of statistically significant differences in element content. Sites in grassland habitat produced more significant differences in element content than either chaparral or streamside habitats for samples from Peromyscus maniculatus. Peromyscus boylii and P. truei provided additional data, but no distinct advantages for element monitoring. The data indicate regional influences from geothermal power development on element levels in rodent tissues.     

Habitat inventory at a regional scale: a comparison of estimates of terrestrial Broad Habitat cover from stratified sample field survey and full census field survey for Wales, UK

Estimates of terrestrial Broad Habitat cover for Wales from the Countryside Survey 2000 stratified sample field mapping programme in Britain are compared with the findings of a full census field mapping project, the Habitat Survey of Wales. The Countryside Survey sampling regime comprised a stratified random sample of 1 km squares [corrected] covering <0.5% of the land surface. Comparative assessment indicates that although few of the sample-derived estimates for individual Broad Habitats are within 30% of the full census survey results, relative extents accord with data from the complete census survey for all Broad Habitats apart from Arable & Horticultural. The accuracy of this estimate is improved when the national boundary of Wales is taken into account in the sample stratification scheme. It is suggested that cultural land-use differences between countries render cropland habitat extent less predictable from physical environmental parameters than semi-natural habitat extent. It is also shown that the precision of sample-derived cover estimates is influenced by habitat pattern: the error term associated with habitats of broadly equal extent is greater for those with the most clumped distributions.