| 1. |
- Elberling, Bo, et al.
(författare)
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Soil and Plant Community Characteristics and Dynamics at Zackenberg
- 2008
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Ingår i: High-arctic ecosystem dynamics in a changing climate - Ten years of monitoring and research at Zackenberg Research Station, Northeast Greenland (Advances in Ecological Research). - 0065-2504. - 9780123736659 ; 40, s. 223-248
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Arctic soils hold large amounts of nutrients in the weatherable minerals and the soil organic matter, which slowly decompose. The decomposition processes release nutrients to the plant-available nutrient pool as well as greenhouse gases to the atmosphere. Changes in climatic conditions, for example, changes in the distribution of snow, water balance and the length of the growing season, are likely to affect the complex interactions between plants, abiotic and biotic soil processes as well as the composition of soil micro- and macro-fauna and thereby the overall decomposition rates. These interactions, in turn, will influence soil-plant functioning and vegetation composition in the short as well as in the long term. In this chapter, we report on soils and. plant communities and their distribution patterns in the valley Zackenbergdalen and focus on the detailed investigations within five dominating plant communities. These five communities are located along an ecological gradient in the landscape and are closely related to differences in water availability. They are therefore indirectly formed as a result of the distribution of landforms, redistribution of snow and drainage conditions. Each of the plant communities is closely related to specific nutrient levels and degree of soil development including soil element accumulation and translocation, for example, organic carbon. Results presented here show that different parts of the landscape have responded quite differently to the same overall climate changes the last 10 years and thus, most likely in the future too. Fens represent the wettest sites holding large reactive buried carbon stocks. A warmer climate will cause a permafrost degradation, which most likely will result in anoxic decomposition and increasing methane emissions. However, the net gas emissions at fen sites are sensitive to long-term changes in the water table level. Indeed, increasing maximum active layer depth at fen sites has been recorded together with a decreasing water level at Zackenberg. This is in line with the first signs of increasing extension of grasslands at the expense of fens. In contrast, the most exposed and dry areas have less soil carbon, and decomposition processes are periodically water limited. Here, an increase in air temperatures may increase active layer depth more than at fen sites, but water availability will be critical in determining nutrient cycling and plant production. Field manipulation experiments of increasing temperature, water supply and nutrient addition show that soil-plant interactions are sensitive to these variables. However, additional plant-specific investigations are needed before net effects of climate changes on different landscape and plant communities can be integrated in a landscape context and used to assess the net ecosystem effect of future climate scenarios.
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| 2. |
- Grøndahl, Louise, et al.
(författare)
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Spatial and interannual variability of trace gas fluxes in a heterogeneous High Arctic landscape
- 2008
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Ingår i: High-arctic ecosystem dynamics in a changing climate - Ten years of monitoring and research at Zackenberg Research Station, Northeast Greenland (Advances in Ecological Research). - 0065-2504. - 9780123736659 ; 40, s. 473-498
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Summertime measurements of CO2 and CH4 fluxes were carried out over a range of high-arctic ecosystem types in the valley Zackenbergdalen since 1996 using both chamber and eddy covariance methodology. The net ecosystem CO2 exchange and CH4 flux data presented reveal a high degree of inter-annual variability within the dominant vegetation types in the valley, but also show distinct differences between them. In particular, the wet and dry parts of the valley show distinct differences. In general, the wet parts of the valley, the fens dominated by white cotton grass Eriophorum scheuchzeri, show high productivity, also in comparison with other sites, whereas CO2 uptake rates in the white arctic bell heather Cassiope tetragona and mountain avens Dryas spp.-dominated heaths are much smaller. Also within the different ecosystem types, a high degree of spatial variability can be documented. The spatial variability both within and between ecosystem types is especially pronounced for the CH4 flux and can, at least partly, be related to differences in vegetation composition and water table level. The importance of the CH4 emission from the various ecosystem types is evaluated both in relation to carbon and greenhouse gas budgets. In both wet and drier ecosystem components, inter-annual variability seems best explained through differences in the amount and distribution of snow in spring and the length of the growing season. A large number of replicate chamber measurements carried out over various vegetation types in the valley are used to produce a synthesis of 10 years of flux data available on growing season carbon dynamics and CH4 emission patterns in the individual parts of this high-arctic ecosystem and relates the differences between the ecosystems found in Zackenbergdalen to comparable sites in the circumpolar North.
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| 3. |
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| 4. |
- Brunekreef, Bert, et al.
(författare)
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Clean air in Europe : beyond the horizon?
- 2015
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 45:1, s. 7-10
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Johannessen, Ane, et al.
(författare)
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Long-term air pollution exposure is associated with sick leave 20 years later
- 2018
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Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 52
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Little is known on outdoor air pollution in a long-term perspective and societal costs such as sick leave. In the Nordic countries, recent pollution health impact assessments have had to rely on outdated studies.Aims: To investigate if air pollution exposure is associated with sick leave 20 years later.Methods: We analysed self-reported sick leave (all-cause and respiratory) in 7 466 subjects from Bergen, Gothenburg, Umea, Uppsala in the RHINE3 study in 2010-12. Home addresses were geocoded and linked to annual average concentrations of PM2.5, PM10 and NO2 at RHINE3, 10 years earlier and 20 years earlier, using existing land-use regression (LUR) models. We performed multilevel logistic regression clustered by centre, and adjusted for sex, smoking, education and previous health-related workplace change.Results: Age range in RHINE3 was 40-66 yrs, 34% and 4% reported all-cause and respiratory sick leave during the last year. In the adjusted analyses all-cause sick leave was associated with PM2.520 years earlier (OR per interquartile range (IQR) difference (2.6 µg/m³) 1.12 (95%CI 1.01, 1.24)), and borderline with NO2 (OR per IQR diff (8.1 µg/m³) 1.09 (95%CI 0.99, 1.19)). Respiratory sick leave was associated with PM10 20 years earlier (OR per IQR diff (3.92 µg/m³) 1.54 (95%CI 1.06, 2.25)), and borderline with PM2.5 (OR per IQR diff 1.31 (95%CI 0.97, 1.76)). Pollution exposures at present as well as 10 years earlier were not significantly associated with sick leave.Conclusions: Air pollution exposure in a general population is associated with sick leave in a 20-year perspective. Our findings suggest that even low air pollution levels such as in Northern Europe have societal costs over time.
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| 6. |
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| 7. |
- Melen, Erik, et al.
(författare)
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Spirometric phenotypes from early childhood to young adulthood - A CADSET (Chronic Airway Disease Early Stratification) study
- 2020
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Ingår i: European Respiratory Journal. - : ERS Publications. - 0903-1936 .- 1399-3003. ; 56:Suppl 64
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Results from longitudinal cohort studies show that the lower the lung function in childhood and adulthood, the higher the risk of later chronic airway disease such as COPD. Yet, reliable data is sparse on the prevalence of different types of lung function impairments in the general population of children and young adults, as well as their major determinants.Aim: To report age- and sex-specific prevalences and characteristics of spirometric phenotypes from childhood up to young adulthood.Methods: Lung function data from independent European population-based cohorts involved in the CADSET collaboration were analysed. Pre-bronchodilator FEV1 and FVC data from each cohort were converted into z-scores according to the Global Lung Initiative (GLI) reference system. Overall fit with the GLI spirometry equations was assessed. Airway limitation was defined as a FEV1/FVC z-score < -1.65.Results: Five cohorts provided spirometry data from 10,842 observations in subjects aged 7 to 25 years. Airway limitation was found in around 6-10% across all ages in the cohorts. No evidence of differences between males and females in different age groups were observed. In unadjusted analyses of all cohorts, we found maternal smoking during pregnancy to be associated with airway limitation (p<0.05).Conclusion: Analyses of spirometry data from population-based cohorts in Europe show that the prevalence of airflow limitation according to GLI is substantial (6-10%) and quite similar across cohorts and age groups. These results suggest that airflow limitation can develop early in life and that there are rather small changes in prevalence during childhood.
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| 9. |
- Peralta, Gabriela P., et al.
(författare)
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Body mass index trajectories during adult life and lung function decline
- 2018
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Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 52
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Body mass index (BMI) has been associated with lung function. Whether distinct BMI trajectories during adult life affect lung function differently is unknown. We assessed associations of BMI trajectories from 34 to 54 years with lung function decline over the same period of time in the ECRHS cohort.BMI trajectories were developed using Group-Based Trajectory Modeling on data collected at least twice between ECRHS I and ECRHS III (n=9327). Associations of these trajectories with lung function decline were assessed using mixed linear regression models (adjusted for sex, age, age2, height, smoking status and baseline lung function) in a subgroup (n=3534) with lung function data at ECRHS I and III. As sex-specific analyses showed similar findings, males and females were combined.Four parallel trajectories were identified: ‘normal’, ‘overweight’, ‘obese’ and ‘morbidly obese’ (Fig. 1). Those with higher BMI trajectories had greater decline of FEV1 and FVC than those with ‘normal BMI’ trajectory (Fig. 2).Overweight and obese trajectories of BMI during adult life were associated with greater lung function decline in the ECRHS cohort.
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| 10. |
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