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101.
102.
Mika Nieminen Sirpa Piirainen Ulf Sikström Stefan Löfgren Hannu Marttila Sakari Sarkkola Ari Laurén Leena Finér 《Ambio》2018,47(5):535-545
The objective of this study was to evaluate the potential of different water management options to mitigate sediment and nutrient exports from ditch network maintenance (DNM) areas in boreal peatland forests. Available literature was reviewed, past data reanalyzed, effects of drainage intensity modeled, and major research gaps identified. The results indicate that excess downstream loads may be difficult to prevent. Water protection structures constructed to capture eroded matter are either inefficient (sedimentation ponds) or difficult to apply (wetland buffers). It may be more efficient to decrease erosion, either by limiting peak water velocity (dam structures) or by adjusting ditch depth and spacing to enable satisfactory drainage without exposing the mineral soil below peat. Future research should be directed towards the effects of ditch breaks and adjusted ditch depth and spacing in managing water quality in DNM areas. 相似文献
103.
Ulf Sonesson Frida Anteson JenniferDavis Per-Olow Sjödén 《Ambio-人类环境杂志》2005,34(4):365-369
在对食物生产系统进行环境相关的系统分析中,消费者阶段(家庭运输、烹制、储存和损耗)是整个食物生命周期中对环境产生影响的一个重要因素.然而,家庭是食物链中调查最少的部分.对家庭信息的收集有很多困难,因为家庭数量庞大,同时与食物相关的活动通常会与其它家务劳动活动混合在一起.环境系统分析和消费者研究两领域研究人员相互合作,通过用问卷、日记和采访面谈的方式调查瑞典的家庭,收集了关于家庭食物运输和损耗的数据.每户每周的平均运输距离是28~63km不等,而这主要依靠怎样分配和其它差事相搭配的运输任务.调制食品时的损耗变化范围是0~34%,而不同类型的食品会有所不同.储存的损耗率为0~164%(因为有更多的食物被扔掉,如对食橱的清理,而不是消费).在调制和储存两阶段中奶制品因损耗少而得分最高. 相似文献
104.
Julia Wohlers-Z?llner Antje Biermann Anja Engel Petra D?rge Aleksandra M. Lewandowska Markus von Scheibner Ulf Riebesell 《Marine Biology》2012,159(11):2503-2518
A comparative analysis of data, obtained during four indoor-mesocosm experiments with natural spring plankton communities from the Baltic Sea, was conducted to investigate whether biogeochemical cycling is affected by an increase in water temperature of up to 6?°C above present-day conditions. In all experiments, warming stimulated in particular heterotrophic bacterial processes and had an accelerating effect on the temporal development of phytoplankton blooms. This was also mirrored in the build-up and partitioning of organic matter between particulate and dissolved phases. Thus, warming increased both the magnitude and rate of dissolved organic carbon (DOC) build-up, whereas the accumulation of particulate organic carbon (POC) and phosphorus (POP) decreased with rising temperature. In concert, the observed temperature-mediated changes in biogeochemical components suggest strong shifts in the functioning of marine pelagic food webs and the ocean’s biological carbon pump, hence providing potential feedback mechanisms to Earth’s climate system. 相似文献
105.
Lennart Thomas Bach Ulf Riebesell Scarlett Sett Sarah Febiri Paul Rzepka Kai Georg Schulz 《Marine Biology》2012,159(8):1853-1864
The flux of organic particles below the mixed layer is one major pathway of carbon from the surface into the deep ocean. The magnitude of this export flux depends on two major processes—remineralization rates and sinking velocities. Here, we present an efficient method to measure sinking velocities of particles in the size range from approximately 3–400?μm by means of video microscopy (FlowCAM?). The method allows rapid measurement and automated analysis of mixed samples and was tested with polystyrene beads, different phytoplankton species, and sediment trap material. Sinking velocities of polystyrene beads were close to theoretical values calculated from Stokes’ Law. Sinking velocities of the investigated phytoplankton species were in reasonable agreement with published literature values and sinking velocities of material collected in sediment trap increased with particle size. Temperature had a strong effect on sinking velocities due to its influence on seawater viscosity and density. An increase in 9?°C led to a measured increase in sinking velocities of ~40?%. According to this temperature effect, an average temperature increase in 2?°C as projected for the sea surface by the end of this century could increase sinking velocities by about 6?% which might have feedbacks on carbon export into the deep ocean. 相似文献
106.
Gerald Schernewski Arunas Balciunas Dennis Gräwe Ulf Gräwe Kristina Klesse Marcus Schulz Sylvie Wesnigk David Fleet Mirco Haseler Nils Möllman Stefanie Werner 《Journal of Coastal Conservation》2018,22(1):5-25
Major objectives were to provide a comprehensive dataset on beach macro-litter for parts of the southern Baltic Sea and to analyse if the methodology is fully applicable and a suitable monitoring method in the Baltic. We carried out a regular macro litter beach monitoring (OSPAR methodology, 4 time a year) on 35 beaches along the German and Lithuanian Baltic coast over 2–5 years. Additional experiments addressed the subjectivity of the field surveys and spatio-temporal variability on different scales. We observed no seasonality of the data and a monthly compared to a 3-monthly sampling resulted in 3 times higher annual item numbers. Along the Lithuanian coast, the average number of items per survey varied between 138 and 340 and along the German Baltic coast between 7 and 404, with a median value of 47. All data showed a very high spatio-temporal variability. Using the Matrix Scoring Technique we assessed beach litter sources. With 50% tourism and recreation was the most important source. 3D–transport simulations helped to explain the minor role of shipping as a source and, compared to the North Sea, the low numbers of items on German Baltic beaches. Floating litter had a short duration time in the western Baltic Sea and offshore drift dominated. Further, the common regular beach cleanings reduced the potential for local litter accumulation and translocation. We suggest a monitoring system on 14 Baltic beaches in Germany and 2 in Lithuania and provide cost calculations. The analysis of macro-litter in cormorant nesting material and the search for beached dead animals did not show any result. We can conclude that the macro-litter beach monitoring method is less suitable for Baltic beaches and should only serve as a complementary method in combination with others. 相似文献
107.
Ulf Landstrm 《Environment international》1990,16(4-6)
Laboratory studies carried out in sound chambers give experimental support to the theory that fatigue and wakefulness could be influenced by sound and hearing. The tiring effect is more pronounced during exposure to low frequency noise compared to higher frequencies. A tiring effect was observed at lower levels above the hearing perception curve. As expected, when the sound pressure level was raised or the frequency was increased, stress reactions and alertness was a more frequently occurring effect. The laboratory findings were supported by a field study carried out on lorry drivers. The tiring effect was more pronounced when driving lorries generating higher levels of low-frequency noise compared to lorries generating lower levels. 相似文献
108.
109.
Ulf Sikström 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):137-142
Liming and/or application of specific nutrients have been proposed as countermeasures to the acidification of forest soils
in southern Sweden. In this study the stem growth of Picea abies (L.) Karst. growing on acidic mineral soils in SW Sweden was investigated 10 years after additions of lime (Ca; 3000 kg lime
ha−1), lime plus P (25 kg ha−1) and K (80 kg ha−1), or N in low doses (2 × 10 kg ha−1 yr−1) (treatments: CaPK, Ca, N, CaPKN, and 2Ca2P2K, respectively). Compared with the control, stem growth was increased following
all treatments involving lime additions, including liming alone. The PK addition did not seem to affect growth. The most plausible
cause of the observed growth increases was that the lime additions indirectly increased the supply of plant-available N. The
annual low-dose N addition did not significantly affect growth. This suggests that air-borne deposition of N, which supplies
very small doses of N throughout the year, has a minor or even negligible influence on P. abies growth. 相似文献
110.
Rüdiger W. Brause Ulf Pietruschka 《International journal of occupational safety and ergonomics》2013,19(3):253-269
This paper describes the problems and an adaptive solution for process control in rubber industry. We show that the human and economical benefits of an adaptive solution for the approximation of process parameters are very attractive.The modeling of the industrial problem is done by the means of artificial neural networks. For the example of the extrusion of a rubber profile in tire production our method shows good resuits even using only a few training samples. 相似文献