Confidence and Trust in Public Institution Natural Hazards Management: Case Studies in Urban and Rural China     

Alex Y. Lo  Lewis T. O. Cheung  Anna Ka-Yin Lee  Bixia Xu 《The Professional geographer》2016,68(3):475-484

This research aims to investigate the extent to which urban and rural residents trust grassroots-level institutions and how this might affect community resilience to environmental change in China. It focuses on the commitments of institutional actors and their capacities to manage natural hazards and coordinate the community's response. Semistructured interviews were conducted with megacity (Tianjin) and remote village (Wolong) residents in China. We found that public confidence in grassroots-level institutions is limited due to inherent constraints on resources and power. Residents of Wolong tend to recognize the commitment and role of those institutions in connecting individuals with one another, whereas their urban counterparts in Tianjin remain skeptical. Issues of solidarity might account for this difference. These findings will have implications for state–society cooperation and disaster risk comanagement in both urban and rural China.  相似文献   

Quantifying the Effects of Commercial Clam Aquaculture on C and N Cycling: an Integrated Ecosystem Approach     

Anna E. Murphy  Kyle A. Emery  Iris C. Anderson  Michael L. Pace  Mark J. Brush  Jennie E. Rheuban 《Estuaries and Coasts》2016,39(6):1746-1761

Increased interest in using bivalve cultivation to mitigate eutrophication requires a comprehensive understanding of the net carbon (C) and nitrogen (N) budgets associated with cultivation on an ecosystem scale. This study quantified C and N processes related to clam (Mercenaria mercenaria) aquaculture in a shallow coastal environment (Cherrystone Inlet, VA) where the industry has rapidly increased. Clam physiological rates were compared with basin-wide ecosystem fluxes including primary production, benthic nutrient regeneration, and respiration. Although clam beds occupy only 3 % of the ecosystem’s surface area, clams filtered 7–44 % of the system’s volume daily, consumed an annual average of 103 % of the phytoplankton production, creating a large flux of particulate C and N to the sediments. Annually, N regenerated and C respired by clam and microbial metabolism in clam beds were ～3- and ～1.5-fold higher, respectively, than N and C removed through harvest. Due to the short water residence time, the low watershed load, and the close vicinity of clam beds to the mouth of Cherrystone Inlet, cultivated clams are likely subsidized by phytoplankton from the Chesapeake Bay. Consequently, much of the N released by mineralization associated with clam cultivation is “new” N as it would not be present in the system without bivalve facilitation. Macroalgae that are fueled by the enhanced N regeneration from clams represents a eutrophying process resulting from aquaculture. This synthesis demonstrates the importance of considering impacts of bivalve aquaculture in an ecosystem context especially relative to the potential of bivalves to remove nutrients and enhance C sinks.  相似文献   

First geophysical and shallow ice core investigation of the Kazbek plateau glacier,Caucasus Mountains     

Stanislav S. Kutuzov  Vladimir N. Mikhalenko  Alexi M. Grachev  Patrick Ginot  Ivan I. Lavrentiev  Anna V. Kozachek  Victoria V. Krupskaya  Alexey A. Ekaykin  Levan G. Tielidze  Pavel A. Toropov 《Environmental Earth Sciences》2016,75(23):1488

First-ever ice core drilling at Mt. Kazbek (Caucasus Mountains) took place in the summer of 2014. A shallow ice core (18 m) was extracted from a plateau at ~4500 m a.s.l. in the vicinity of the Mt. Kazbek summit (5033 m a.s.l.). A detailed radar survey showed that the maximum ice thickness at this location is ~250 m. Borehole temperature of ?7 °C was measured at 10 m depth. The ice core was analyzed for oxygen and deuterium isotopes and dust concentration. From the observed seasonal cycle, it was determined that the ice core covers the time interval of 2009–2014, with a mean annual snow accumulation rate of 1800 mm w. eq. Multiple melt layers have been detected. δ¹⁸O values vary from ?25 to ?5‰. The dust content was determined using a particle sizing and counting analyzer. The dust layers were investigated using scanning electron microscopy and X-ray diffraction analysis. Dust can be separated into two categories by its origin: local and distant. Samples reflecting predominantly local origin consisted mainly of magmatic rocks, while clay minerals were a characteristic of dust carried over large distances, from the deserts of the Middle East and Sahara. The calculated average dust flux over three years at Kazbek was of 1.3 mg/cm² a^?1. Neither δ¹⁸O nor dust records appear to have been affected by summer melting. Overall, the conditions on Kazbek plateau and the available data suggest that the area offers good prospects of future deep drilling in order to obtain a unique environmental record.  相似文献   

Changing structure of benthic foraminiferal communities: implications from experimentally grown assemblages from coastal Georgia and Florida,USA          下载免费PDF全文

Anna E. Weinmann  Susan T. Goldstein 《Marine Ecology》2016,37(4):891-906

Environmental changes such as ocean warming or sea‐level rise have a profound impact on shallow‐water coastal environments. Benthic foraminifera have long been successfully used as indicators for ecologic responses. The propagule method is a useful tool to evaluate the reactions of entire assemblages of foraminifera when exposed to different environmental conditions. Here we present results from growth experiments of foraminiferal assemblages from three sites in coastal Georgia and Florida (USA) under different temperatures (18, 24 and 30 °C) and salinities (15 and 35). Results show that assemblages grown at the higher temperatures had greater abundances of foraminifera, whereas salinity was the primary factor in shaping the composition of the experimentally grown assemblages from the three sites. We also show that experimentally grown assemblages contain high numbers of ‘exotic’ species that result from successful propagule recruitment from outside of the original environments (e.g. the open shelf). Overall, opportunistic and previously termed ‘pioneer species’ proved to be the most successful constituents of the experimental assemblages, showing that reactions of foraminiferal assemblages to environmental changes can appear remarkably quickly (e.g. in the course of several weeks). Our observations on the faunal reactions to different temperatures and salinities indicate that ongoing environmental alterations of coastal areas will likely result in significant changes in the shallow‐water foraminiferal assemblages of the coasts of Georgia and Florida. As such, our study provides general insights into the ecologic effects of current climate change.  相似文献   

From Jurassic rifting to Cretaceous subduction in NW Iranian Azerbaijan: geochronological and geochemical signals from granitoids     

Anna?LechmannEmail authorView author&#;s OrcID profile  Jean-Pierre?Burg  Peter?Ulmer  Ali?Mohammadi  Marcel?Guillong  Mohammad?Faridi 《Contributions to Mineralogy and Petrology》2018,173(12):102

Previous interpretations of a Jurassic subduction in Iran were based on trace element classification diagrams for granitoids, but their reliability is questionable, underscored by modern examples of continental break-up zones such as the Baja California. We present new field observations, bulk rock geochemistry, Sr and Nd isotope analyses and U–Pb zircon geochronology to assess the age and tectonic setting of previously undated intermediate to felsic magmatic rocks cropping out in the Precambrian basement of NW Iranian Azerbaijan. The geochronology revealed an uneven distribution in space and time: Late Jurassic (159–154 Ma) intrusions and dikes are alkaline to calc-alkaline. Their melt source is mantle dominated with a distinct continental contribution disclosed by radiogenic isotopes and abundant inherited zircon cores. Mid-Cretaceous (112–96 Ma) plutonic bodies and associated volcanic rocks occur only to the east of the major Siah Cheshmeh–Khoy Fault. They have geochemical signatures typical of a metasomatized mantle. In consistence with the sedimentation history of the area, our new interpretation attributes the Late Jurassic magmatism to thinning of a continental lithosphere in a rift-related setting. Mid-Cretaceous magmatism was produced by oceanic subduction beneath the Central Iran continent. We interpret the 40-Ma age gap between the two magmatic episodes as the time of opening of the oceanic basin witnessed by the Khoy ophiolite in the study area.  相似文献   

Thermal expansion on volcanic tuff rocks used as building stones: examples from Mexico     

Rubén López-Doncel  Wanja Wedekind  Alfredo Aguillón-Robles  Reiner Dohrmann  Sergio Molina-Maldonado  Theresa Leiser  Anna Wittenborn  Siegfried Siegesmund 《Environmental Earth Sciences》2018,77(9):338

Three cities in the center of Mexico, declared as cultural heritage, were erected mainly of volcanic tuffs as main construction element. Many of the historic buildings of these cities show significant damage and deterioration. One of the causes of these damages can be attributed to a phenomenon poorly studied in volcanic tuffs, the thermal expansion. To understand the response of volcanic tuffs to thermal expansion, as well as to know their thermal expansion coefficient, thermal expansion test was performed on 12 representative tuffs of these localities. In the same way and to know which of their petrographic, petrophysical, mineralogical, and geochemical properties influence this phenomenon, several laboratory studies were carried out to determine which of these plays an important role in the expansion. The results of our tests showed that volcanic tuffs rocks have very varied thermal expansion values, ranging from 0.7 mm/m at their maximum expansion to even contraction in the order of ??0.5 mm/m. Equally varied were the thermal expansion coefficient values ranging from 10.1 to ??7.2 10^?6/K. The most dominant behavior type is the “anisotropic no residual strain behavior”. In general, the behavior of the tuffs in practically all the tests carried out showed a very important heterogeneity in the rocks; however, in spite of the non-homogeneous behavior of the tuffs, three main factors could be identified that play an important role in the thermal expansion of the studied rocks, the chemical composition, e.g., acid volcanic tuff rocks (rhyolitic composition) had greater expansions, while the more basic rocks (basaltic composition) expanded less, the textural and fabrics homogeneity, e.g., the most homogeneous rocks texturally have higher expansion values and the degree of crystallinity, and, e.g., the tuff rocks with the largest amount of glass showed smaller thermal expansions than the tuffs composed of microcrystals.  相似文献   

Calcium Carbonate and Phosphate Reference Materials for Monitoring Bulk and Microanalytical Determination of Sr Isotopes          下载免费PDF全文

Michael Weber  Federico Lugli  Klaus Peter Jochum  Anna Cipriani  Denis Scholz 《Geostandards and Geoanalytical Research》2018,42(1):77-89

In situ laser ablation analyses rely on the microanalytical homogeneity of reference materials (RMs) and a similar matrix and mass fraction between unknown samples and RMs to obtain reliable results. Suitable carbonate and phosphate RMs for determination of Sr isotope ratios in such materials are limited. Thus, we determined ⁸⁷Sr/⁸⁶Sr ratios of several carbonate (JCt‐1, JCp‐1, MACS‐1, MACS‐3) and phosphate (MAPS‐4, MAPS‐5, NIST SRM 1400, NIST SRM 1486) international RMs using dissolved samples and two different multi‐collector inductively coupled plasma‐mass spectrometers (MC‐ICP‐MS). Our Sr isotope data are in agreement with published data and have an improved measurement precision for some RMs. For MACS‐1, we present the first ⁸⁷Sr/⁸⁶Sr value. We tested the suitability of these materials for microanalytical analyses by LA‐MC‐ICP‐MS, with two different laser ablation systems: a conventional nanosecond laser and a state‐of‐the‐art femtosecond laser. We investigated the RMs micro‐homogeneity and compared the data with our solution data. Both laser ablation systems yielded identical ⁸⁷Sr/⁸⁶Sr ratios within uncertainty to the solution data for RMs with low interferences of REEs. Therefore, these carbonate and phosphate RMs can be used to achieve accurate and precise results for in situ Sr isotope investigations by LA‐MC‐ICP‐MS of similar materials.  相似文献   

Rapid characterisation of the extremely large landslide threatening the Rules Reservoir (Southern Spain)     

Reyes-Carmona  Cristina  Galve  Jorge Pedro  Moreno-Sánchez  Marcos  Riquelme  Adrián  Ruano  Patricia  Millares  Agustín  Teixidó  Teresa  Sarro  Roberto  Pérez-Peña  José Vicente  Barra  Anna  Ezquerro  Pablo  López-Vinielles  Juan  Béjar-Pizarro  Marta  Azañón  José Miguel  Monserrat  Oriol  Mateos  Rosa María 《Landslides》2021,18(12):3781-3798

Landslides - When an active landslide is first identified in an artificial reservoir, a comprehensive study has to be quickly conducted to analyse the possible hazard that it may represent to such...  相似文献   

Dating recent floodplain sediments in the Hawkesbury‐Nepean River system,eastern Australia using single‐grain quartz OSL     

Anna K. Sim  Kristina J. Thomsen  Andrew S. Murray  Geraldine Jacobsen  Russell Drysdale  Wayne Erskine 《Boreas: An International Journal of Quaternary Research》2014,43(1):1-21

Two fluvial sediment cores taken from a floodplain of the Hawkesbury‐Nepean River system in the Sydney region, eastern Australia are dated using Optically Stimulated Luminescence (OSL) to provide a reliable chronology essential for the management and planning of water resources. Nine charcoal ¹⁴C (AMS) dates constrain these OSL ages. Quartz extracted from seven OSL samples from each of the cores was measured using both single‐grain and multi‐grain OSL techniques. Three of the single‐grain natural dose distributions appear to be well bleached, but the others appear to be incompletely bleached to various degrees. Three minimum‐age models (MAM, MAM_UL and IEU) are applied to the single‐grain dose distributions. We conclude that these models give consistent age estimates. For one of the cores it appears to be necessary to use a minimum‐age model to obtain accurate ages, but in the other core incomplete bleaching is probably less important than postdepositional mixing and mixing during sampling. As a result, the burial age is probably best estimated using the weighted average of the individual single‐grain dose estimates. The application of multi‐grain OSL techniques to these samples results in an average apparent age overestimation of ～200 years, which is significant for these samples, but negligible for sediments older than a few thousand years. The intention is that the chronology obtained in this study will be used in conjunction with a proxy flood record, derived from floodplain sediments, to gain an understanding of the long‐term variability in periods of high and low rainfall in eastern Australia.  相似文献   

Deep electrical resistivity structure of the northern Gibraltar Arc (western Mediterranean): evidence of lithospheric slab break‐off     

Oriol Rosell  Anna Martí  Àlex Marcuello  Juanjo Ledo  Pilar Queralt  Eduard Roca  Joan Campanyà 《地学学报》2011,23(3):179-186

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