Social–ecological memory in urban gardens—Retaining the capacity for management of ecosystem services     

Stephan Barthel  Carl Folke  Johan Colding 《Global Environmental Change》2010,20(2):255-265

Many ecosystem services are in decline. Local ecological knowledge and associated practice are essential to sustain and enhance ecosystem services on the ground. Here, we focus on social or collective memory in relation to management practice that sustains ecosystem services, and investigate where and how ecological practices, knowledge and experience are retained and transmitted. We analyze such social–ecological memory of allotment gardens in the Stockholm urban area, Sweden. Allotment gardens support ecosystem services such as pollination, seed dispersal and pest regulation in the broader urban landscape. Surveys and interviews were preformed over a four-year period with several hundreds of gardeners. We found that the allotment gardens function as communities-of-practice, where participation and reification interact and social–ecological memory is a shared source of resilience of the community by being both emergent and persistent. Ecological practices and knowledge in allotment gardens are retained and transmitted by imitation of practices, oral communication and collective rituals and habits, as well as by the physical gardens, artifacts, metaphors and rules-in-use (institutions). Finally, a wider social context provides external support through various forms of media, markets, social networks, collaborative organizations, and legal structures. We exemplify the role of urban gardens in generating ecosystem services in times of crisis and change and conclude that stewards of urban green areas and the social memory that they carry may help counteract further decline of critical ecosystem services.  相似文献   

Analytic element modelling for strip aquifers     

José Anderson N. Batista  Edson Wendland  Harry E. Schulz 《水文研究》2012,26(8):1254-1262

The Analytic Element Method (AEM) provides a convenient tool for groundwater flow analysis in unbounded continuous domains. The AEM is based on the superposition of analytic functions, known as elements, useful at both regional and local scales. In this study, analytic elements for strip aquifers are presented. Such aquifers occur in riverine or coastal deposits and in outcrop zones of confined aquifers. Local flow field is modelled indirectly, using a reference plane related to the aquifer domain through the Schwarz‐Christoffel transform. The regional flow is obtained as a solution of the one‐dimensional flow equation. The proposed methodology was tested by modelling two hypothetical situations, which were compared to exact solutions. It is shown that regional boundaries can be reproduced exactly while local fields are adequately reproduced with analytic elements. The developed elements are applied to simulate a real flow field in northeastern Brazil showing good agreement with measured water levels. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Verschmutzungen durch alkylierte Phenole in der Deutschen Bucht     

Dr. Norbert Theobald  Dr. Gerhard Dahlmann  Stephan Dick 《Ocean Dynamics》1991,44(5-6):345-360

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Isothermal compression of low-cordierite to 30 kbar (25° C)     

P. W. Mirwald  M. Malinowski  Heinz Schulz 《Physics and Chemistry of Minerals》1984,11(3):140-148

The compression of cordierite (Mg, Fe)₂Al₄Si₅O₁₈·n (H₂O, CO₂; Na⁺, K⁺) has been studied up to 30 kbar (25° C) by volumetric measurements with a piston cylinder apparatus and by X-ray measurements with a diamond-anvil cell. Natural cordierite of intermediate Mg-Fe composition and synthetic Mg-cordierite served as samples. Two discontinuities at 2.2±0.3 and 9.0±0.6 kbar which are correlated with very small volume changes (0.3?0.05%) have been found. The X-ray data indicate, however, no symmetry change of the crystal structure. The two discontinuities are interpreted as phase transitions. The two discontinuities establish three pressure dependent phases referred to as low-pressure (LP)-, first high-pressure (HP1)- and second high-pressure (HP2)-phase. The gross compressibility of cordierite decreases from 1.1 Mbar^?1 at low pressure to 0.7 Mbar^?1 at 30 kbar for the intermediate Mg-Fe cordierite, and to 0.4 Mbar^?1 for Mg-cordierite. Depending on the pressure transmitting medium used in the two different compression techniques, two kinds of compression behavior are observed for cordierite. The measurements with the piston cylinder apparatus where lead is used as quasihydrostatic pressure medium indicate normal compression properties. The X-ray data, however, obtained with the diamond anvil cell where a methanol-ethanol mixture provides hydrostatic pressure conditions yield, e.g. for the HP1-phase a dramatic decrease in compressibility to almost zero. IR-spectra from samples of augmenting experiments with methanol, deuteromethanol and D₂O as pressure media indicate that pressure media of which the molecule size is comparable with the dimensions of the cordierite channels may be incorporated in the structure. This suggests that under such hydrostatic conditions the compression of cordierite is modified by a structure internal component which is acting via the channel system.  相似文献   

Migration und Translokation von Blei und Cadmium im Lysimeterversuch     

F. Schulz  W. Gerlich  M. Schwan 《洁净——土壤、空气、水》1986,14(4):439-442

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Middle miocene deduction and late miocene beginning of collision registered in the hengchun peninsula: Geodynamic implications for the evolution of Taiwan     

Bernard Pelletier  Jean Franois Stephan 《Tectonophysics》1986,125(1-3)

Taiwan is located in the axis of the Manila Trench. It results from an oblique collision between the northernmost part of the Luzon arc and the Chinese passive margin. This active collision follows the subduction of the Oligocene-Miocene oceanic crust of the South China Sea along the Manila Trench. The tectonized Chinese margin emerged in the Hengchun peninsula (South Taiwan). Gentle folds which are delineated by the Quaternary reefal limestones demonstrate Recent deformations. These folds deformed a thick detrital sequence of Miocene age (Ssuchung Chi series) which was previously strongly folded and thrust westward (axis NS-N20) upon the Renting mélange of Latest Miocene age. These main deformations, sealed by the Middle Pliocene, are the evidence for the onset of collision in this part of Taiwan at the end of the Miocene. Because of its obliquity, the collision started already in the northern part of Taiwan during the Late Miocene (6-7-8 Ma ?).The Ssuchung Chi series, a sequence of proximal turbidites, has contained, since the Middle Miocene (NN 6~13 Ma), fragments of an Oligocene to Lower Miocene oceanic crust. This ophiolitic material is very similar to the East Taiwan Ophiolite of the Coastal Range. It originated most probably from a slice of South China Sea crust obducted in Middle Miocene times (13–14 Ma) upon the Chinese margin (North of the Hengchun peninsula). This obduction occurred 7 to 8 Ma before the beginning of collision. These results make it possible to propose an evolutionary model for Taiwan from the Oligocene to the Recent, with the different phases of a collision between a volcanic arc and a passive margin.  相似文献   

Reconstructions of spring/summer precipitation for the Eastern Mediterranean from tree-ring widths and its connection to large-scale atmospheric circulation     

Ramzi Touchan  Elena Xoplaki  Gary Funkhouser  Jürg Luterbacher  Malcolm K. Hughes  Nesat Erkan  Ünal Akkemik  Jean Stephan 《Climate Dynamics》2005,25(1):75-98

This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years to 600 years. The first reconstruction (1885–2000) was derived from principal components (PCs) of 36 combined chronologies. The remaining five, 1800–2000, 1700–2000, 1600–2000, 1500–2000 and 1400–2000 were developed from PCs of 32, 18, 14, 9, and 7 chronologies, respectively. Calibration and verification statistics for the period 1931–2000 show good levels of skill for all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed May–August precipitation, was 5 years (1591–1595) and occurred only once during the last 600 years. The longest reconstructed wet period was 5 years (1601–1605 and 1751–1755). No long term trends were found in May–August precipitation during the last few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation. In general, tree-ring indices are influenced by May–August precipitation, which is driven by anomalous below (above) normal pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the southern regions and warmer (cooler) conditions north of around 40°N. A compositing technique is used to extract information on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution related to extreme dry and wet summers were identified both for the most recent 50 years and the last 237 years. Except for the last few decades, running correlation analyses between the major European-scale circulation patterns and eastern Mediteranean spring/summer precipitation over the last 237 years are non-stationary and insignificant, suggesting that local and/or sub-regional geographic factors and processes are important influences on tree-ring variability over the last few centuries.  相似文献   

Earthquakes in Switzerland and surrounding regions during 2006     

Manfred Baer  Nicolas Deichmann  Jochen Braunmiller  John Clinton  Stephan Husen  Donat Fäh  Domenico Giardini  Philipp Kästli  Urs Kradolfer  Stefan Wiemer 《Swiss Journal of Geoscience》2007,100(3):517-528

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2006. During this period, 572 earthquakes and 91 quarry blasts were detected and located in the region under consideration. Of these earthquakes, two occurred in conjunction with the construction of the new Gotthard railway tunnel and 165 were induced artificially by the stimulation of a proposed geothermal reservoir beneath the city of Basel. With 20 events with M _L ≥ 2.5, five of which were artificially induced, the seismic activity in the year 2006 was far below the average over the previous 31 years. Nevertheless, six events were felt by the public, most prominently the strongest of the induced Basel events (M _L 3.4), which caused some non-structural building damage. Noteworthy are also the two earthquakes near Cortaillod (M _L 3.2), on the shore of Lake Neuchatel, and in Val Mora (M _L 3.5), between the Engadin and Val Müstair, as well as the 42 aftershocks of the M _L 4.9 Vallorcine earthquake, between Martigny and Chamonix, of September 2005. Editorial handling: Stefan Bucher  相似文献   

The Cloud Ice Mountain Experiment (CIME) 1998: experiment overview and modelling of the microphysical processes during the seeding by isentropic gas expansion     

Wolfram Wobrock  Andrea I. Flossmann  Marie Monier  Jean-Marc Pichon  Laurent Cortez  Jean-Franois Fournol  Alfons Schwarzenbck  Stephan Mertes  Jost Heintzenberg  Paolo Laj  Giordano Orsi  Loretta Ricci  Sandro Fuzzi  Harry Ten Brink  Piet Jongejan  Ren Otjes 《Atmospheric Research》2001,58(4):7907

The second field campaign of the Cloud Ice Mountain Experiment (CIME) project took place in February 1998 on the mountain Puy de Dôme in the centre of France. The content of residual aerosol particles, of H₂O₂ and NH₃ in cloud droplets was evaluated by evaporating the drops larger than 5 μm in a Counterflow Virtual Impactor (CVI) and by measuring the residual particle concentration and the released gas content. The same trace species were studied behind a round jet impactor for the complementary interstitial aerosol particles smaller than 5 μm diameter. In a second step of experiments, the ambient supercooled cloud was converted to a mixed phase cloud by seeding the cloud with ice particles by the gas release from pressurised gas bottles. A comparison between the physical and chemical characteristics of liquid drops and ice particles allows a study of the fate of the trace constituents during the presence of ice crystals in the cloud.In the present paper, an overview is given of the CIME 98 experiment and the instrumentation deployed. The meteorological situation during the experiment was analysed with the help of a cloud scale model. The microphysics processes and the behaviour of the scavenged aerosol particles before and during seeding are analysed with the detailed microphysical model ExMix. The simulation results agreed well with the observations and confirmed the assumption that the Bergeron–Findeisen process was dominating during seeding and was influencing the partitioning of aerosol particles between drops and ice crystals. The results of the CIME 98 experiment give an insight on microphysical changes, redistribution of aerosol particles and cloud chemistry during the Bergeron–Findeisen process when acting also in natural clouds.  相似文献   

Behaviour of H₂O₂, NH₃, and black carbon in mixed-phase clouds during CIME     

Paolo Laj  Andrea I. Flossmann  Wolfram Wobrock  Sandro Fuzzi  Giordano Orsi  Loretta Ricci  Stephan Mertes  Alfons Schwarzenbck  Jost Heintzenberg  Harry Ten Brink 《Atmospheric Research》2001,58(4):256

We investigated the partitioning of trace substances during the phase transition from supercooled to mixed-phase cloud induced by artificial seeding. Simultaneous determination of the concentrations of H₂O₂, NH₃ and black carbon (BC) in both condensed and interstitial phases with high time resolution showed that the three species undergo different behaviour in the presence of a mixture of ice crystals and supercooled droplets. Both H₂O₂ and NH₃ are efficiently scavenged by growing ice crystals, whereas BC stayed predominantly in the interstitial phase. In addition, the scavenging of H₂O₂ is driven by co-condensation with water vapour onto ice crystals while NH₃ uptake into the ice phase is more efficient than co-condensation alone. The high solubility of NH₄⁺ in the ice could explain this result. Finally, it appears that the H₂O₂–SO₂ reaction is very slow in the ice phase with respect to the liquid phase. Our results are directly applicable for clouds undergoing limited riming.  相似文献