Towards a better understanding of the Oulmes hydrogeological system (Mid-Atlas,Morocco)     

Samuel Wildemeersch  Philippe Orban  Ingrid Ruthy  Olivier Grière  Philippe Olive  Abdelkhalek El Youbi  Alain Dassargues 《Environmental Earth Sciences》2010,60(8):1753-1769

Located in the Mid-Atlas (Morocco), the Oulmes plateau is famous for its mineral water springs “Sidi Ali” and “Lalla Haya” commercialised by the company “Les Eaux minérales d’Oulmès S.A”. Additionally, groundwater of the Oulmes plateau is intensively exploited for irrigation. The objective of this study, essentially performed from data collected during isotopic (summer 2004) and piezometric and hydrogeochemical field campaigns (spring 2007), is to improve the understanding of the Oulmes hydrogeological system. Analyses and interpretation of these data lead to the statement that this system is constituted by a main deep aquifer of large extension and by minor aquifers in a perched position. However, these aquifers interact enough to be in total equilibrium during the cold and wet period. As highlighted by isotopes, the origin of groundwater is mainly infiltration water except a small part of old groundwater with dissolved gas rising up from the granite through the schists.  相似文献   

The effects of controlled drainage on subsurface outflow from level agricultural fields     

Ingrid Wesstrm  Gunnar Ekbohm  Harry Linnr  Ingmar Messing 《水文研究》2003,17(8):1525-1538

Daily outflow frequencies and recession curves were used to identify differences in storage–outflow relationships between two different drainage systems, conventional and controlled drainage. A three‐year (1996–1999) field drainage experiment was carried out on a loamy sand soil in southern Sweden. Plots with an area of 0·2 hectares were drained by conventional subsurface drainage (CD) or by controlled drainage (CWT1 and CWT2). The controlled drainage system allowed the groundwater level in the soil to be varied during the year. It was kept at least 70 cm below the soil surface during the growing season but allowed to rise to a maximum of 20 cm below the soil surface during the rest of the year. Measurements were performed to record precipitation, drain outflow and groundwater levels. Daily values of outflow were divided into 10 categories, based on the size of outflow. Recession curves of hourly measurement of outflow were selected. They behaved like single reservoirs and a linear storage–outflow model was applied. Least squares estimates of the parameters initial outflow, initial storage volume and retention constant were calculated. Controlled drainage had a significant effect on total drain outflow and outflow pattern during the three years of measurement. The total drain outflow was 70% to 90% smaller in CWT than in CD. The analysis revealed that the initial outflows were higher, the retention constant and the temporary storage lower in CWT. The hydrological impacts of the reduction in temporary storage were higher peak flow, shorter lag time and shorter recession time and these effects increased with an increased groundwater level. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Changes in Dogger Bank macrofauna communities in the 20th century caused by fishing and climate     

Ingrid Kröncke 《Estuarine, Coastal and Shelf Science》2011,94(3):234-245

The macrofauna communities on the Dogger Bank (North Sea) from the 1920s, the 1950s and the 1980s to the 2000s were compared and identified five communities with similar spatial distribution throughout the 20th century. The abundance of dominant species in the five communities varied with time. Most obvious in the 1950s was the loss of the extensive Spisula and Mactra patches, which covered most of the shallow parts of the Bank in the 1920s. Since the 1980s, they have been found only as juveniles. The biological regime shift in the late 1980s caused an increase in macrofauna abundance, species numbers, diversity and southern species in most of the communities. The climate regime shift in 2001 had opposite effects in which the abundance, species numbers, diversity and southern species decreased in most of the communities. The increase in interface-feeding species and the decrease in sand-licking amphipods in the 2000s especially in the shallow Bank Community give evidence for climate driven changes in water masses, currents, storms, turbidity and food availability via planktonic or benthic primary production. Both fishing impact and climate change are hypothesised as explaining the changes in the Dogger Bank macrofauna communities.  相似文献   

Dust in the solar system and in extra-solar planetary systems     

Ingrid Mann  Melanie Köhler  Hiroshi Kimura  Andrzej Cechowski  Tetsunori Minato 《Astronomy and Astrophysics Review》2006,13(3):159-228

Among the observed circumstellar dust envelopes a certain population, planetary debris disks, is ascribed to systems with optically thin dust disks and low gas content. These systems contain planetesimals and possibly planets and are believed to be systems that are most similar to our solar system in an early evolutionary stage. Planetary debris disks have been identified in large numbers by a brightness excess in the near-infrared, mid-infrared and/or submillimetre range of their stellar spectral energy distributions. In some cases, spatially resolved observations are possible and reveal complex spatial structures. Acting forces and physical processes are similar to those in the solar system dust cloud, but the observational approach is obviously quite different: overall spatial distributions for systems of different ages for the planetary debris disks, as opposed to detailed local information in the case of the solar system. Comparison with the processes of dust formation and evolution observed in the solar system therefore helps understand the planetary debris disks. In this paper, we review our present knowledge of observations, acting forces, and major physical interactions of the dust in the solar system and in similar extra-solar planetary systems.  相似文献   

Erratum to “Dust grains in the comae and tails of sungrazing comets: modeling of their mineralogical and morphological properties”: [Icarus 159, 529-541 (2002)]     

Hiroshi Kimura  Ingrid Mann  Elmar K. Jessberger 《Icarus》2004,169(2):505-506

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Microheterogeneity of element distribution and sulfur speciation in an organic surface horizon of a forested Histosol as revealed by synchrotron-based X-ray spectromicroscopy     

Jörg Prietzel  Ingrid Kögel-KnabnerJürgen Thieme  David PatersonIan McNulty 《Organic Geochemistry》2011,42(11):1308-1314

In recent years, the relevance of physico-chemical heterogeneity patterns in soils at the micron and submicron scale for the regulation of biogeochemical processes has become increasingly evident. For an organic surface soil horizon from a forested Histosol in Germany, microspatial patterns of element distribution (sulfur, phosphorus, aluminium, silicon) and S speciation were investigated by synchrotron-based X-ray spectromicroscopy. Microspatial patterns of S, P, Al and Si contents in the organic topsoil were assessed for a sample region of 50 μm × 30 μm by spatially resolving μ-XRF. Sulfur speciation at four microsites was investigated by focused X-ray absorption near edge structure (μ-XANES) spectroscopy at the S K-edge. The results show a heterogeneous distribution of the investigated elements on the (sub)micron scale, allowing the identification of diatoms, aluminosilicate mineral particles and sulfide minerals in the organic soil matrix. Evaluation of the S K-edge μ-XANES spectra acquired at four different microsites by linear combination fitting revealed a substantial microspatial heterogeneity of S speciation, characterized by the presence of distinct enrichment zones of inorganic sulfide and zones with dominant organic disulfide S within a few micrometers distance, and coexistence of different S species (e.g. reduced inorganic and organic S compounds) at a spatial scale below the resolution of the instrument (60 nm × 60 nm; X-ray penetration depth: 30 μm).  相似文献   

Impact airblast triggers dust avalanches on Mars     

Kaylan J. Burleigh  Henry J. Melosh  Livio L. Tornabene  Boris Ivanov  Alfred S. McEwen  Ingrid J. Daubar 《Icarus》2012,217(1):194-201

Visible images from the Mars Reconnaissance Orbiter have revealed more than 200 new impact sites on Mars (almost all in dust-mantled regions) containing 1–50 m diameter craters, often in clusters. We count approximately 65,000 small-scale slope streaks within 2 to 3 km of one such cluster and categorize them into four morphologically distinct types. Here we show that these slope streaks (interpreted as dust avalanches) are triggered by the impact event but, surprisingly, are not due to seismic shaking; instead, the dust avalanches are due to airblasts created by the supersonic meteor(s) before impact. Sixteen of the new impact sites are associated with high areal densities of dust avalanches. The observed dust avalanche frequency suggests that impact-generated airblasts constitute a locally important and previously unrecognized process for inducing slope degradation on Mars.  相似文献   

Causal thinking and support for climate change policies: International survey findings     

Ann Bostrom  Robert E. O’Connor  Gisela Böhm  Daniel Hanss  Otto Bodi  Frida Ekström  Pradipta Halder  Sven Jeschke  Birgit Mack  Mei Qu  Lynn Rosentrater  Anethe Sandve  Ingrid Sælensminde 《Global Environmental Change》2012,22(1):210-222

Few comparative international studies describe the climate change policies people are willing to support and the reasons for their support of different policies. Using survey data from 664 economics and business undergraduates in Austria, Bangladesh, Finland, Germany, Norway, and the United States, we explore how perceived risk characteristics and mental models of climate change influence support for policy alternatives. General green policies such as funding research on renewable technologies and planting trees were the overwhelmingly most popular policy alternatives. Around half the students support carbon reduction policies such as requiring higher car fuel efficiency and increasing taxes on fossil fuels. Least popular were engineering alternatives such as fertilizing the oceans and replacing fossil fuels with nuclear power. Variations among nations are generally small. Support for different policy alternatives corresponds with different causal thinking. Those who hold a pollution model of the causes of climate change, tend to blame environmental harms (e.g., air pollution from toxic chemicals), see general green policy alternatives as effective, and support general green policies. Support of carbon reduction strategies is associated with seeing carbon emissions as the cause and reducing carbon emissions as effective solutions. Support of engineering solutions increases with identifying volcanoes among causes and regarding engineering solutions as effective. Although these international students agree that climate change is a threatening problem, their causal thinking correlates with support for different mitigative policy actions, with the most popular ones not necessarily the most effective.  相似文献   

Melanistic southern right‐whale dolphins (Lissodelphis peronii) off Kaikoura,New Zealand,with records of other anomalously all‐black cetaceans     

Ingrid N. Visser  Dagmar Fertl  L. Todd Pusser 《新西兰海洋与淡水研究杂志》2013,47(5):833-836

Reports of anomalously pigmented cetaceans, including melanistic (all‐black) individuals are infrequent. We observed four melanistic southern right‐whale dolphins (Lissodelphis peronii) including a calf, off Kaikoura (42°34'S, 173°50'E), New Zealand. We also compiled records of melanistic individuals from five other species of cetaceans. The ecological context of melanistic pigmentation of cetaceans is not well understood; however, it may increase heat absorption, affect ability to capture prey, impair visual/social communication, and/or increase conspicuousness to predators.  相似文献   

A synthesis of Cenozoic sedimentation in the North Sea     

Ingrid Anell  Hans Thybo  Erik Rasmussen 《Basin Research》2012,24(2):154-179

The North Sea Basin contains an almost complete record of Cenozoic sedimentation, separated by clear regional unconformities. The changes in sediment characteristics, rate and source, and expression of the unconformities reflect the tectonic, eustatic and climatic changes that the North Sea and its margins have undergone. While the North Sea has been mapped locally, we present the first regional mapping of the Cenozoic sedimentary strata. Our study provides a new regional sub‐division of the main seismic units in the North Sea together with maps of depocentres, influx direction and source areas. Our study provides a regional synthesis of sedimentation based on a comprehensive interpretation of a regionally covering reflection seismic data set. We relate observations of sediment characteristics and unconformities to the geological evolution. The timing, regional expression and stratigraphic characteristics of many unconformities indicate that they were generated by eustatic sea‐level fall, often in conjunction with other processes. Early Cenozoic unconformities, however, relate to tectonism associated with the opening of the North Atlantic. From observation on a regional scale, we infer that the sediment influx into the North Sea during the Cenozoic is more complex than previously suggested clockwise rotation from early northwestern to late southern sources. The Shetland Platform supplied sediment continuously, although at varying rates, until the latest Cenozoic. Sedimentation around Norway changed from early Cenozoic influx from the southwestern margin, to almost exclusively from the southern margin in the Oligocene and from all of southern Norway in the latest Cenozoic. Thick Eocene deposits in the Central Graben are sourced mainly from a western and a likely southern source, indicating that prominent influx from the south did not only occur from the mid‐Miocene onwards. We infer a new age for the increased progradational sediment influx in the Pleistocene of 2.5 Ma, coeval with Fennoscandian glaciation.  相似文献