ENSO-coupled precipitation records (1959–2004) based on shells of freshwater bivalve mollusks (<Emphasis Type="Italic">Margaritifera falcata</Emphasis>) from British Columbia     

Bernd R. Schöne  Nicholas A. Page  David L. Rodland  Jens Fiebig  Sven Baier  Samuli O. Helama  Wolfgang Oschmann 《International Journal of Earth Sciences》2007,96(3):525-540

We present the results of sclerochronologically calibrated growth and stable isotope analyses of the freshwater bivalve Margaritifera falcata collected from an agricultural, suburban setting near Vancouver, BC. The oxygen isotope range of shell aragonite can be explained by the temperature range during the growing season, assuming the water δ ¹⁸O composition remained constant. However, shell growth is strongly influenced by local summer precipitation and potentially runoff of nutrient-rich stormwater. About 44% of the variability of annual shell growth can be explained by amounts of local summer (June–September) rainfall. Local winter precipitation and El Niño–Southern Oscillation (ENSO) strength during the preceding year exert a weak, but significant control on shell growth. In combination, summer and winter precipitation can explain up to 50% of the variability in annual shell growth. Spectral analyses substantiate the effect of precipitation on shell growth and demonstrate that shell growth and ENSO are coupled by precipitation. Common spectral density was found at periods of 6.5–9 years, particularly between 1985 and 2004. Higher frequency oscillation corresponding to periods of 3–5 years occurred during the early 1970s, early to mid 1980s, and later 1990s. These results suggest that skeletal records of bivalve mollusks provide suitable archives of ENSO-coupled precipitation in areas where other climate proxies such as tree-rings and speleothems may not be available.  相似文献   

Enhancing integrated indoor/outdoor mobility in a smart campus     

Joaquín Torres-Sospedra  Joan Avariento  David Rambla  Raúl Montoliu  Sven Casteleyn  Mauri Benedito-Bordonau 《International journal of geographical information science》2015,29(11):1955-1968

A Smart City relies on six key factors: Smart Governance, Smart People, Smart Economy, Smart Environment, Smart Living and Smart Mobility. This paper focuses on Smart Mobility by improving one of its key components: positioning. We developed and deployed a novel indoor positioning system (IPS) that is combined with an outdoor positioning system to support seamless indoor and outdoor navigation and wayfinding. The positioning system is implemented as a service in our broader cartography-based smart university platform, called SmartUJI, which centralizes access to a diverse collection of campus information and provides basic and complex services for the Universitat Jaume I (Spain), which serves as surrogate of a small city. Using our IPS and based on the SmartUJI services, we developed, deployed and evaluated two end-user mobile applications: the SmartUJI APP that allows users to obtain map-based information about the different facilities of the campus, and the SmartUJI AR that allows users to interact with the campus through an augmented reality interface. Students, university staff and visitors who tested the applications reported their usefulness in locating university facilities and generally improving spatial orientation.  相似文献   

Testing unbaited stygofauna traps for sampling performance     

Jrg Bork  Sabine Bork  Sven E. Berkhoff  Hans Jürgen Hahn 《Limnologica》2008,38(2):105-115

Unbaited phreatic traps are a promising new method for sampling subterranean limnofauna. The aim of this study is to evaluate whether such trap systems are suitable to gather representative samples of the physico-chemical parameters and the invertebrate fauna of the aquifer. Fifteen traps, installed in five groundwater bores, and four traps located in the hyporheic zone, were sampled twice monthly over a 1 year period (June 2003–June 2004). Water samples were removed in three separated fractions (hose, trap and aquifer water), analysed for physico-chemical and faunal characteristics and compared with one another. The study was carried out in the Nakdong River floodplain, Korea. Physico-chemical characteristics of trap and aquifer were similar, but differed greatly from the hose samples. Abundances of fauna inside the traps were higher than in the aquifer, whereas there were no differences in taxonomic composition of the trap and aquifer samples. Biases of abundances suspected due to the use of traps were negligible in the groundwater, though it is recommended that comparisons between groundwater and hyporheic abundances ascertained by traps be handled cautiously.  相似文献   

Kinematics of elliptical galaxies with a diffuse dust component – II. Dust effects on kinematic modelling     

Maarten Baes  †  Herwig Dejonghe  Sven De Rijcke† 《Monthly notices of the Royal Astronomical Society》2000,318(3):798-808

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净化湖泊饮用水源的物理-生态工程实验研究   总被引：37，自引：7，他引：30  

濮培民  胡维平  逄勇  魏阳春  刘雪芬  张静仪  颜京松  李文朝  SvenEricJφrgensen 《湖泊科学》1997,9(2):159-167

我国许多历史上水质优良的湖泊水源区已污染严重污染,净化饮用水源刻不容缓。本文介绍了自１９９１年以来太源进行的物理－生态工程的部分研究成果。着重介绍在太湖的重富营养湖湾－五里湖无锡中桥自来水厂水源区的静态和抽水动态实验。  相似文献   

Semantic Enablement for Spatial Data Infrastructures   总被引：4，自引：0，他引：4  

Krzysztof Janowicz  Sven Schade  Arne Bröring  Carsten Keßler  Patrick Maué  Christoph Stasch 《Transactions in GIS》2010,14(2):111-129

Building on abstract reference models, the Open Geospatial Consortium (OGC) has established standards for storing, discovering, and processing geographical information. These standards act as a basis for the implementation of specific services and Spatial Data Infrastructures (SDI). Research on geo‐semantics plays an increasing role to support complex queries and retrieval across heterogeneous information sources, as well as for service orchestration, semantic translation, and on‐the‐fly integration. So far, this research targets individual solutions or focuses on the Semantic Web, leaving the integration into SDI aside. What is missing is a shared and transparent Semantic Enablement Layer for SDI which also integrates reasoning services known from the Semantic Web. Instead of developing new semantically enabled services from scratch, we propose to create profiles of existing services that implement a transparent mapping between the OGC and the Semantic Web world. Finally, we point out how to combine SDI with linked data.  相似文献   

Combined use of aerogammaspectrometry and geochemistry to access sediment sources in a shallow coral site at Armação dos Búzios,Brazil     

Danielly Godiva  Heitor Evangelista  Milton Kampel  Marcus Vinicius Licinio  Casimiro Munita 《Estuarine, Coastal and Shelf Science》2010

Coral and reef environments in shallow waters are negatively affected by human activities in several coastal areas worldwide. It has been demonstrated that sediment influx and macronutrient discharges induce decline of coral population structure and diversity. Therefore, efforts to quantify sediment flux, sources and the biological response to sedimentation were conducted by several marine researchers. Herein, we investigated the case study of Armação dos Búzios/Brazil/Western South Atlantic, where coral colonies (mostly Siderastrea stellata) are under stress due to sediment apportionment as a consequence of regional human occupation. Classification of potential sediment source regions was based on a high-resolution aerogammaspectrometry survey for ²³²Th, ²³⁸U and ⁴⁰K in main land near shore, used as primarily tool, in combination with sediment geochemistry. This approach allowed distinguishing three hydrographic basins (Macaé river basin, São João river basin and Una river basin) as potential sources. Hierarchical cluster analysis applied to the set of parameters identified the Macaé River as the most probable sediment contributor to the coralline site.  相似文献   

Investigating Hologram-Based Route Planning     

Sven Fuhrmann  Oleg Komogortsev  Dan Tamir 《Transactions in GIS》2009,13(S1):177-196

It is often assumed that three-dimensional topographic maps provide more effective route planning, navigation, orientation, and way-finding results than traditional two-dimensional representations. The research reported here investigates whether three-dimensional spatial mappings provide better support for route planning than two-dimensional representations. In a set of experiments performed as part of this research, human subjects were randomly shown either a two- or three-dimensional hologram of San Francisco and were asked to plan a bicycling route between an origin and a destination point. In a second task, participants used these holograms to identify the highest elevation point in the displayed area. The eye-movements of the participants, throughout the process of looking at the geospatial holograms and executing the tasks, were recorded. The eye-tracking metrics analysis indicates with a high statistical level of confidence that three-dimensional holographic maps enable more efficient route planning. In addition, the research group is developing a new algorithm to analyze the differences between participant-selected routes and a set of "good routes." The algorithm employs techniques used to represent the boundary of objects and methods for assessing the difference between objects in modern digital image recognition, image registration, and image alignment applications. The overall goal is to create a theoretical framework for investigating and quantifying route planning effectiveness.  相似文献   

Assessment of the exploitable biomass of thread herring(Opisthonema spp.) in northwestern Mexico     

Marcelino Ruiz-Domínguez  Casimiro Qui?onez-Velázquez  Dana Isela Arizmendi-Rodriguez  Víctor Manuel Gómez-Mu?oz  Manuel Otilio Nevárez-Martínez 《海洋学报(英文版)》2021,40(9):53-65

In recent years, the small pelagic fishery on the Pacific northwest coast of Mexico has significantly increased fishing pressure on thread herring Opisthonema spp. This fishery is regulated using a precautionary approach(acceptable biological catch(ABC) and minimum catch size). However, due to fishing dynamics, fish aggregation habits and increased fishing mortality, periodic biomass assessments are necessary to estimate ABC and assess the resource status. The Catch-MSY approach was used to analyze historical series of thread herring catches off the western Baja California Sur(BCS, 1981–2018) and the Gulf of California(GC, 1972–2018) to estimate exploitable biomass and target reference points in order to obtain catch quotas. According to the results, in GC,the maximum biomass reached in 1972(at the beginning of fishery) and minimum biomass reached in 2015; the estimated exploitable biomass for 2019 was 42.2×10~4 t; and the maximum sustainable yield(MSY) was 15.4×10~4 t.In the western BCS coast, the maximum biomass was reached in 1981(at the beginning of fishery) and minimum biomass was reached in 2017; the estimated exploitable biomass for 2019 was 3.2×10~4 t; and the MSY was 1.2×10~4 t.Both stocks showed a decrease in biomass over the past years and were currently near to point of full exploitation.The results suggest that the use of the Catch-MSY method is suitable to obtain annual biomass estimates, in order to establish an ABC, to know the current state of the resource, and to avoid overcoming the potential recovery of the stocks.  相似文献   

Benthic Foraminifera as ecological indicators for water quality on the Great Barrier Reef   总被引：1，自引：0，他引：1  

Sven Uthicke  Kristie Nobes 《Estuarine, Coastal and Shelf Science》2008,78(4):763-773

Benthic foraminifera are established indicators for Water Quality (WQ) in Florida and the Caribbean. However, nearshore coral reefs of the Great Barrier Reef (GBR) and other Pacific regions are also subjected to increased nutrient and sediment loads. Here, we investigate the use of benthic foraminifera as indicators to assess status and trends of WQ on GBR reefs. We quantified several sediment parameters and the foraminiferan assemblage composition on 20 reefs in four geographic regions of the GBR, and along a water column nutrient and turbidity gradient. Twenty-seven easily recognisable benthic foraminiferan taxa (>63 μm) were distinguished. All four geographic regions differed significantly (p < 0.05, ANOSIM) in their assemblage composition, and a redundancy analysis (RDA) showed that sediment parameters only explained a small proportion of the variance in the assemblage composition. On nine reefs along a previously studied water quality gradient, foraminifera showed a distinct shift in assemblage composition towards larger symbiont-bearing taxa from turbid inner shelf towards clearer outer shelf reefs. A RDA separated symbiotic and aposymbiotic (heterotrophic) taxa. In addition, total suspended solid and water column chlorophyll a concentrations were negatively correlated, and optical depth and distance to the mainland were positively correlated, with the abundance of symbiont-bearing taxa. Several large foraminifera were identified as indicators for offshore, clear water conditions. In contrast, heterotrophic rotaliids and a species retaining plastids (Elphidium sp.) where highly characteristic for low light, higher nutrient conditions. Application of the FORAM index to GBR assemblage composition showed a significant increase in the value of this index with increased distance from the mainland in the Whitsunday region (r² = 0.75, p < 0.001), and therefore with increasing light and decreased nutrient availability. We conclude that it will be possible to apply this index to GBR and possibly other Pacific reefs after some adaptations and additional experimental work on species-specific limiting factors.  相似文献