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1.
The effect of nitrogen on biomass production, shoot elongation and relative density of the mosses Pleurozium schreberi, Hylocomium splendens and Dicranum polysetum was studied in a chamber experiment. Monocultures were exposed to 10 N levels ranging from 0.02 to 7.35 g N m−2 during a 90-day period. All the growth responses were unimodal, but the species showed differences in the shape parameters of the curves. Hylocomium and Pleurozium achieved optimum biomass production at a lower N level than Dicranum. Pleurozium had the highest biomass production per tissue N concentration. Tolerance to N was the widest in Dicranum, whereas Hylocomium had the narrowest tolerance. Dicranum retained N less efficiently from precipitation than the other two species, which explained its deviating response. All species translocated some N from parent to new shoots. The results emphasize that the individual responses of bryophytes to N should be known when species are used as bioindicators.  相似文献   
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Soils emit a large variety of volatile organic compounds. In natural ecosystems, measurements of microbial volatile organic compound (MVOC) exchange rates between soil and atmosphere are difficult due to e.g. the spatial heterogeneity of the belowground organisms, and due to the many potential sources for the same compounds. We measured in laboratory conditions the MVOC emission rates and spectra of eight typical fungi occurring in boreal forest soils. The studied species are decomposers (Gymnopilus penetrans, Ophiostoma abietinum), ectomycorrhizal (Cenococcum geophilum, Piloderma olivaceum, Suillus variegatus, Tomentellopsis submollis) and endophytic fungi (Meliniomyces variabilis, Phialocephala fortinii). The MVOC emissions contained altogether 21 known and 6 unidentified compounds whose emission rates were >0.1 μg g(DW)?1 h?1. The most abundant compounds were the short-chain carbonyl compounds (acetone and acetaldehyde). The greatest carbonyl emissions were measured from P. olivaceum (1.9 mg acetone g(DW)?1 h?1) and P. fortinii (0.114 mg acetaldehyde g(DW)?1 h?1). Terpenoid emissions (isoprene, mono- and sesquiterpenes) were detected from some fungal cultures, but in relatively small amounts. We conclude that soil micro-organisms can potentially be responsible for significant emissions of volatiles, especially short-chain oxygenated compounds, to the below-canopy atmosphere.  相似文献   
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The international recovered paper trade serves two important functions: increasing raw material availability in the paper and board industry and providing economic incentives to recycle. The purpose of this paper is to shed further light on emerging patterns in this trade by empirically analysing the changes in the bilateral trade flows of recycled paper between 1992 and 2008. According to our estimations, two important changes occurred in the 1990s and 2000s. First, the growing importance of developing economies in global recycled paper trade plays a significant role in import demand as a determinant of trade flows. Second, the changes in global trade patterns necessitate investigating the transportation cost measures used in applied research.  相似文献   
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Technology innovation is an increasingly globalized exercise with dramatic consequences for scientific and diplomatic goals alike, and requires enhanced participation and integration of scientists and science-minded diplomats within diplomatic missions to advance shared policy goals. This more general problem is addressed in the present article by focusing on recent collaborations between U.S. and German scientists, including several of the coauthors.  相似文献   
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Contribution of particulate phosphorus to runoff phosphorus bioavailability   总被引:1,自引:0,他引:1  
Runoff P associated with eroded soil is partly solubilized in receiving waters and contributes to eutrophication, but the significance of particulate phosphorus (PP) in the eutrophying P load is debatable. We assessed losses of bioavailable P fractions in field runoff from fine-textured soils (Cryaquepts). Surface runoff at four sites and drain-flow at two of them was sampled. In addition to dissolved molybdate-reactive phosphorus (DRP) losses, two estimates of bioavailable PP losses were made: (i) desorbable PP, assessed by anion exchange resin-extraction (AER-PP) and (ii) redox-sensitive PP, assessed by extraction with bicarbonate and dithionite (BD-PP). Annual losses of BD-PP and AER-PP were derived from the relationships (R2 = 0.77-0.96) between PP and these P forms. Losses of BD-PP in surface runoff (94-1340 g ha(-1)) were typically threefold to fivefold those of DRP (29-510 kg ha(-1)) or AER-PP (13-270 g ha(-1)). Where monitored, drainflow P losses were substantial, at one of the sites even far greater than those via the surface pathway. Typical runoff DRP concentration at the site with the highest Olsen-P status (69-82 mg kg(-1)) was about 10-fold that at the site with the lowest Olsen P (31-45 mg kg(-1)), whereas the difference in AER-PP per mass unit of sediment was only threefold, and that of BD-PP 2.5-fold. Bioavailable P losses were greatly influenced by PP runoff, especially so on soils with a moderate P status that produced runoff with a relatively low DRP concentration.  相似文献   
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The copper (Cu) resistance of Arctostaphylos uva-ursi was tested in a pot experiment (lasting 8 weeks) using rooted cuttings originating from an area near the Harjavalta Cu-Ni smelter, SW Finland. The fine roots were moderately infected by arbutoid mycorrhizae. The plants were exposed to five Cu levels (1, 10, 22, 46 and 100 mg l(-1)) given repeatedly together with a nutrient solution. The critical Cu concentration in the nutrient solution inhibiting the growth of A. uva-ursi was below 10 mg l(-1) Cu (EC(50) value for biomass production 3.3 mg l(-1) Cu). This concentration was clearly lower than the value we have found earlier for other dwarf shrubs under similar experimental conditions. Most of the Cu given accumulated in the roots and old stems. The results suggest that A. uva-ursi cuttings were relatively sensitive to Cu despite the ability of the adult clones to grow in Cu-contaminated soil. The adult clones extend their roots into the less toxic deeper soil layers, which may facilitate the avoidance of heavy metals.  相似文献   
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The effects of Ergorest® arm supports on wrist angles and musculoskeletal strain in the neck-shoulder-arm region and electrical activity in the shoulder and arm muscles were studied during typing or the use of the mouse in work with a visual display unit (VDU). Twenty-one women were randomized into 3 groups (1 arm support, 2 arm supports, and control). Measurements were carried out before and after the 6-week intervention. The wrist extension of the mouse hand, the muscle activity of the trapezius muscle, and the subjective discomfort ratings indicated that 2 arm supports were better than 1 in work with a mouse. The Ergorest® arm support alleviates muscle and joint strain in VDU work when used for both arms.  相似文献   
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Cultural sustainability has become a much discussed topic in the forestry and bioenergy sectors. However, there are not many indicators available for measuring cultural sustainability. In order to identify indicators for the assessment of the cultural sustainability impacts of wood-based bioenergy in eastern Finland, two-phased expert interviews were conducted. The process was supported by a hybrid approach: A qualitative mapping technique was applied when the indicators were identified, and weights for the indicators were set using a quantitative rating technique. The experts identified 49 indicators of cultural sustainability. Most of the generated indicators were relevant for local uses and highlighted the perceptions of the general public. Furthermore, most of the indicators were relevant from the perspective of raw material acquisition. Applying methods of differing backgrounds enabled advanced problem structuring, which allowed the identification of indicators suitable for assessing cultural sustainability of wood-based bioenergy in Eastern Finland. The quantitative rating technique enabled the determination of the importance of the indicators generated. Nevertheless, it seems that the hybrid approaches have many challenges related to the quantitative measuring of the participants’ perceptions. Cultural sustainability indicators should be identified within a case study, since it seems that most of the cultural sustainability indicators are case specific. The process introduced here offers steps for identifying case-specific cultural sustainability indicators; however, the concept of cultural sustainability cannot be strictly defined.  相似文献   
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