Created by the Monte Peron rock avalanche: Lago di Vedana (Dolomites,Italy) and its sediment record of landscape evolution after a mass wasting event     

Zolitschka  Bernd  Polgar  Irene Sophie  Behling  Hermann 《Landslides》2022,19(2):297-311

The timing of the Monte Peron Landslide is revised to 2890 cal. BP based on a radiocarbon-dated sediment stratigraphy of Lago di Vedana. This age fosters the importance of hydroclimatic triggers in the light of accelerating global warming with a predicted increase of precipitation enhancing the regional predisposition to large landslides. Moreover, a layer enriched in allochthonous organic and minerogenic detritus dating to the same wet period is interpreted as response to a younger and yet unidentified mass wasting event in the catchment of Lago di Vedana. Rock debris of the Monte Peron Landslide impounded the Cordevole River valley and created a landslide-dammed lake. Around AD 1150, eutrophication of this lacustrine ecosystem started with intensified human occupation – a process that ended 150 years later, when the river was diverted back into its original bed. Most likely, this occurred due to artificial opening of the river dam. In consequence, Lago di Vedana was isolated from an open and minerogenic to an endorheic and carbonaceous lacustrine system. After a monastery was established nearby in AD 1457, a second eutrophication process was initiated due to intensified land use linked with deforestation. Only in the eighteenth and nineteenth centuries, deposition of organic matter decreased coinciding with climatic (Little Ice Age) and cultural changes. Conversational measures are the likely reasons for a trend towards less eutrophic conditions since AD 1950.

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The influence of environmental variability of a coastal lagoon ecosystem on genetic diversity and structure of white seabream [Diplodus sargus (Linnaeus 1758)] populations          下载免费PDF全文

Raquel Hernández‐García  Irene Muñoz  Antonio López‐Capel  Concepción Marcos  Ángel Pérez‐Ruzafa 《Marine Ecology》2015,36(4):1144-1154

As coastal lagoons serve as nursery areas for some marine and estuarine fish, selective pressures of these brackish or hypersaline lagoons may influence the genetic structure of species and populations. We examined spatial and temporal genetic patterns at eight microsatellite loci in white seabream [Diplodus sargus (Linnaeus 1758)] recruits from the Mar Menor (Southeast Spain) and compared these loci with those in coastal populations from the open sea, observing a high degree of genetic diversity and spatio‐temporal genetic stability. However, the results suggest the presence of subpopulations or genetic substructures in the Mar Menor D. sargus population that could be interpreted as a homogeneous mixture of individuals from three differentiated subpopulations in the Mediterranean and evidence of the Wahlund effect. It also suggests that D. sargus adults return to their original spawning habitat, thus conserving the genetic differences among the respective populations over time. Overall, this study demonstrates the importance of the Mar Menor coastal lagoon as a nursery area for the conservation of genetic diversity of D. sargus populations.  相似文献   

Social Exclusion and the Disabled: An Accessibility Approach*   总被引：1，自引：0，他引：1  

Irene Casas 《The Professional geographer》2007,59(4):463-477

Understanding social dimensions (e.g., transport equity) is an important aspect of sustainable development. This holistic perspective allows the use of accessibility as a tool to identify disadvantaged groups. In this article, cumulative accessibility measures are calculated for a sample of individuals who participated in a one‐day travel diary survey for the Buffalo‐Niagara region in the state of New York. These measures, which include the number of opportunities available in an individual's activity space, are used to compare the levels of access between disabled and nondisabled groups and to determine if individuals' disabilities and other characteristics are contributing factors to their exclusion. Findings show that being young, coming from a small household, possessing a driver's license, having a steady job, living in an urban setting, and being willing to travel a long distance increase the number of opportunities available.  相似文献   

Biomarkers in upper Holocene Eastern North Sea and Wadden Sea sediments     

Bart E. van Dongen  W. Irene C. Rijpstra  Catharina J. M. Philippart  Jan W. de Leeuw  Jaap S. Sinninghe Damst 《Organic Geochemistry》2000,31(12)

Total extracts of sediment cores from five different stations in the North Sea and Wadden Sea were analysed for their biomarker composition. Only sediments of the Skagerrak contained significant amounts of marine biomarkers (mainly alkenones), other sites contained predominantly terrestrial biomarkers. Bioturbation in the Skagerrak is, however, far too high to determine sea surface temperature (SST) changes within short time intervals. These results indicate that biomarkers contained in these sediments are not useful to reconstruct climate fluctuations during the upper Holocene. High amounts of α-, β- and ω-hydroxy fatty acids as well as small amounts of α, β-dihydroxy fatty acids were released from the insoluble organic material of the sediments from the Wadden Sea station, indicating a significant input of the eelgrass Zostera marina. This was confirmed by microscopic observations. This is the first time the α,β-dihydroxy fatty acids have been found in a sediment core and they have proven to be potential biomarkers for these seagrass species.  相似文献   

IGU commission on the coastal environment no. 32, August 1992     

Roland Paskoff  Irene Campari  Andrew U. Frank 《GeoJournal》1992,27(4):392-396

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Mean sea level and the marine geoid—an analysis of concepts     

Irene Fischer 《Marine Geodesy》2013,36(1):37-59

The current ambition to achieve a 10‐cm marine geoid focuses attention on the interdisciplinary problem of relating oceanographic to geodetic measurements, and on the apparent conflict between them along the United States’ coasts. The concepts underlying the comparisons in this conflict are analyzed, and shown to leave a possibility of diffusing the deadlock by more precise reformulations. Concepts which have been equated in practical applications under less stringent accuracy requirements need to be refined and related more precisely through interdisciplinary efforts. An example is given of a geodetic utilization of density differences in the ocean, akin to but not the same as the idea of steric leveling, in order to highlight the similarity and dissimilarity between some geodetic and oceanographic ideas.  相似文献   

Background levels of potentially toxic metals from soils of the Pisa coastal plain (Tuscany, Italy) as identified from sedimentological criteria     

Alessandro Amorosi  Irene Sammartino  Giovanni Sarti 《Environmental Earth Sciences》2013,69(5):1661-1671

Identification of reliable background values of potentially toxic metals in sediments requires detailed integration of geochemical data with accurate sedimentological studies. Through analysis of 60 soil samples from the Pisa coastal plain, this study shows to what extent sediment provenance and facies characteristics may influence the natural distribution of potentially toxic metals (Cr, Ni, Cu, Zn, Pb) within alluvial and coastal sediments. Metals supplied to the alluvial plain are mostly concentrated within the finest sediment fraction (floodplain clays), while coarser crevasse and overbank deposits exhibit invariably lower metal contents. Beach-ridge sands display the lowest metal concentrations. Transport of ophiolitic detritus by the longshore drift may account for locally high Cr concentrations within beach deposits. Geochemical fingerprinting of individual facies associations in terms of natural metal contents results in the construction of a geologically-based geochemical map. This map offers a more reliable depiction of spatial distribution of background levels than interpolation techniques based uniquely upon statistical methods. Matching background values against metal concentrations from topsoil samples leads to the reliable assessment of the pollution status of Pisa coastal plain. Metal contents exceeding the threshold values designated for contaminated areas (Cr) simply reflect catchment geology, and are not the product of artificial contamination. On the other hand, anthropogenic disturbance may be detected even where metal contents (Pb, Cu) lie below the threshold values. The use of sedimentological criteria is presented here as a pragmatic tool to enhance predictability of natural metal contents in sediments, with obvious positive feedbacks for legislative purposes and environmental protection.  相似文献   

The paradox of gender discrimination in land ownership and women’s contribution to poverty reduction in Anglophone Cameroon     

L. Fonjong  Lawrence Fombe  Irene Sama-Lang 《GeoJournal》2013,78(3):575-589

Land is the core of the predominantly agrarian economy of Cameroon. It is therefore an important factor of production to both men and women particularly in rural areas. While the legal framework in Cameroon advocate for equal rights and opportunities to resources, the majority of rural women who are mostly peasant farmers can neither inherit nor own land due to gender discriminatory customary practices. This study examines some of the arguments for sustaining these customary practices that violate women’s rights over the years and the role of these ‘landless’ women in poverty alleviation. The study is based on a field survey which was conducted among some 2,205 respondents in 2009 using questionnaires, interviews and focus group discussions in Anglophone Cameroon. The findings revealed that although women are the livewire of rural households and key players in the struggle against poverty who depend solely on land, they still do not have security of tenure over the land they cultivate. The paper argues that even though women are assuming increasing roles in the education of the children, provision of food and paying for medical services for the homes, there are still some traditional belief systems that work against their rights to land. These belief systems have a strong grip on the attitudes and perception of both men and women on women’s rights to land in that even when men and women are unanimous on the need for women to own land, they both disagree on how they should own the land. The logical outcome of this dilemma is that men own the land while women work on it. The latter have very little possibilities to carry out any long term investment on land without the blessing of the former. We thus, advocate for gender mainstreaming in land reforms and gender consciousness among traditional authorities, men and even among the women as some of the ways of redressing gender discrimination in land ownership rights and poverty particularly in rural areas.  相似文献   

On the Atlantic–Pacific Niños connection: a multidecadal modulated mode     

Marta Martín-Rey  Belén Rodríguez-Fonseca  Irene Polo  Fred Kucharski 《Climate Dynamics》2014,43(11):3163-3178

Atlantic and Pacific El Niño are the leading tropical oceanic variability phenomena at interannual timescales. Recent studies have demonstrated how the Atlantic Niño is able to influence on the dynamical processes triggering the development of the Pacific La Niña and vice versa. However, the stationarity of this interbasin connection is still controversial. Here we show for the first time that the Atlantic–Pacific Niños connection takes place at particular decades, coinciding with negative phases of the Atlantic Multidecadal Oscillation (AMO). During these decades, the Atlantic–Pacific connection appears as the leading coupled covariability mode between Tropical Atlantic and Pacific interannual variability. The mode is defined by a predictor field, the summer Atlantic Sea Surface Temperature (SST), and a set of predictand fields which represent a chain of atmospheric and oceanic mechanisms to generate the Pacific El Niño phenomenon: alteration of the Walker circulation, surface winds in western Pacific, oceanic Kelvin wave propagating eastward and impacting on the eastern thermocline and changes in the Pacific SST by internal Bjerknes feedback. We suggest that the multidecadal component of the Atlantic acts as a switch for El Niño prediction during certain decades, putting forward the AMO as the modulator, acting through changes in the equatorial Atlantic convection and the equatorial Pacific SST variability. These results could have a major relevance for the decadal prediction systems.  相似文献   

Changes in submerged macrophyte abundance altered diatom and chironomid assemblages in a shallow lake     

Jesse C. Vermaire  Marie-Hélène Greffard  Émilie Saulnier-Talbot  Irene Gregory-Eaves 《Journal of Paleolimnology》2013,50(4):447-456

Submerged macrophyte abundance strongly influences aquatic ecosystems. Because of a lack of monitoring data, however, the long-term dynamics of such aquatic plants are poorly understood. Increasingly, paleolimnologists use changes in subfossil algae and invertebrates to infer past submerged macrophyte dynamics and assess how human activities have altered this important primary producer component of aquatic ecosystems. We evaluated the sensitivity of subfossil diatom and chironomid assemblages to historically documented changes in macrophyte abundance in Chenango Lake, New York, USA, where macrophyte cover has been monitored since 1978. We also tested the ability of a semi-quantitative diatom-based macrophyte-abundance inference model to detect the pronounced macrophyte decline that was observed between 1993 and 2001. Diatoms responded to the recent loss of macrophytes, with a decline in the relative abundance of macrophyte-associated taxa. Estimates of macrophyte abundance fluctuated according to the diatom-based inference model. Chironomid changes were coherent with the diatom-inferred macrophyte zones. The largest shifts in subfossil assemblages occurred before the start of the monitoring record and coincided with construction of a ~4.3-m-high dam on the lake, which substantially expanded the littoral habitat. Even in heavily managed systems, large reductions in macrophyte abundance can be detected with paleolimnological approaches.  相似文献