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31.
Moored fish aggregating devices (MFADs) are used by small-scale fishers to access fish species difficult to harvest in large numbers. In the case of Guadeloupe (Caribbean area), the use of MFADs has increased considerably and this is causing congestion in these fishing areas and creating conflict between fishers. The aim of this article is to understand how informal fishing territories around the La Desirade Island were established and examine these territories through the lens of economic defendability theory. Results of semistructured interviews show that MFAD fishers display territoriality along MFAD tract lines forming quasi-privatized areas. Territoriality in this article is based on the following factors: the type of targeted resources, the cost of harvesting, the defending of territories, and the acknowledgment of territories by the fishing community. Conflicts and utilization of MFADs (overcapacity) have raised an opportunity to create co-managed legalized territorial use rights for fisheries. 相似文献
32.
Olivier Jacquat Andreas Voegelin Farid Juillot Ruben Kretzschmar 《Geochimica et cosmochimica acta》2009,73(19):5554-5571
In order to better understand the long-term speciation and fractionation of Zn in soils, we investigated three soils naturally enriched in Zn (237–864 mg/kg Zn) from the weathering of Zn-rich limestones (40–207 mg/kg Zn) using extended X-ray absorption fine structure (EXAFS) spectroscopy and sequential extractions. The analysis of bulk EXAFS spectra by linear combination fitting (LCF) indicated that Zn in the oolitic limestones was mainly present as Zn-containing calcite (at site Dornach), Zn-containing goethite (Gurnigel) and Zn-containing goethite and sphalerite (Liestal). Correspondingly, extraction of the powdered rocks with 1 M NH4-acetate at pH 6.0 mobilized only minor fractions of Zn from the Gurnigel and Liestal limestones (<30%), but most Zn from the Dornach rock (81%). In the Dornach soil, part of the Zn released from the dissolving limestone was subsequently incorporated into pedogenic hydroxy-interlayered vermiculite (Zn-HIV, 30%) and Zn-containing kaolinite (30%) and adsorbed or complexed by soil organic and inorganic components (40%). The Gurnigel and Liestal soils contained substantial amounts of Zn-containing goethite (50%) stemming from the parent rock, smaller amounts (20%) of Zn-containing kaolinite (and possibly Zn-HIV), as well as adsorbed or complexed Zn-species (30%). In the soil from Liestal, sphalerite was only found in trace amounts, indicating its dissolution during soil formation. In sequential extractions, large percentages of Zn (55–85%) were extracted in recalcitrant extraction steps, confirming that Zn-HIV, Zn-containing kaolinite and Zn-containing goethite are highly resistant to weathering. These Zn-bearing phases thus represent long-term hosts for Zn in soils over thousands of years. The capability of these phases to immobilize Zn in heavily contaminated soils may however be limited by their uptake capacity (especially HIV and kaolinite) or their abundance in soil. 相似文献
33.
34.
Olivier Merle Philippe Mairine Laurent Michon Patrick Bachèlery Magali Smietana 《Journal of Volcanology and Geothermal Research》2010,189(1-2):131-142
Based upon a re-interpretation of previous data and a new field campaign, a structural evolution is proposed for the early history of Piton de la Fournaise volcano from 500,000 to 50,000 years. Conceptually, it is shown that the formation of a caldera in which lava flows are contained inside the caldera depression, gives time for erosion to excavate deep canyons on the external slopes of the volcano, for example, the Rivière des Remparts, the Rivière Langevin and the Rivière de l'Est canyons on Piton de la Fournaise volcano. These canyons are infilled when lavas, filling the caldera and overflowing its rim, are able again to flow on the external slopes of the volcano. In the past, this excavating/infilling process has occurred twice following the formation of the Rivière des Remparts and Morne Langevin calderas. The formation of the third caldera, the Plaine des Sables caldera, was followed by the excavation of the current canyons. In addition to this process, two large landslides have been documented in the field. The first, which happened about 300,000 years ago, is apparently the first episode of the break up of Piton de la Fournaise volcano, predating the formation of the four large calderas. The second landslide, which occurred 150,000 years ago and is considered to be less extensive, has carried away the entire southern flank of the Rivière des Remparts caldera. 相似文献
35.
Dr Par Olivier L. Reymond 《Aquatic Sciences - Research Across Boundaries》1983,45(2):405-408
A method allowing isolation of phytoplancton algae for unialgal cultures is briefly described. Advantages and limits of the method are discussed. 相似文献
36.
Dr. Olivier L. Reymond 《Aquatic Sciences - Research Across Boundaries》1983,45(2):409-410
A new flat embedding method is commented. This method allows embedding of the same phytoplankton sample for light and transmission electron microscopy. Rare or interesting field specimens can then be easily selected and sectioned without the need of cultures. A great range of biological material can be handled with this method. 相似文献
37.
G. Gleizes D. Leblanc P. Olivier J. Bouchez 《International Journal of Earth Sciences》2001,90(2):325-340
This microstructural and anisotropy of magnetic susceptibility study of the internal structures of the Hercynian Néouvielle granite pluton (100 km2) provides new data indicating that the pluton was emplaced during the main Hercynian tectonic event recognized in the Pyrenees. It also provides new data about the later Alpine deformation localized along narrow mylonitic bands. These bands acted as reverse faults and have not rotated the Hercynian structures that define the main part of the pluton. The pluton is composed of two structural domains: the northern half of the pluton displays a beak shape in map view, with subhorizontal E-W trending lineations of magmatic origin; the southern half is semi-circular and displays rather steeply northward plunging lineations corresponding to magmatic and high temperature (HT) solid-state microstructures. These features are associated with magma deformation during emplacement. Magma deformation corresponds, in the northern half of the pluton, to an E-W strike-slip deformation recognized in the enveloping pelitic metasediments of Carboniferous age and, in the southern half of the pluton, to southward overthrusting recognized in the enveloping quartzites of Devonian age. Juxtaposition in a single granite body of transcurrent and compressive domains is viewed as a strain partitioning in the magma. This strain partitioning is linked to both the transpressive character of the main regional deformation event and the rheological contrast between the pelitic country rocks and quartzose country rocks. 相似文献
38.
Olivier Harifidy Ralison Alberto Vieira Borges Frank Dehairs J.J. Middelburg Steven Bouillon 《Organic Geochemistry》2008,39(12):1649
Madagascar’s largest estuary (Betsiboka) was sampled along the salinity gradient during the dry season to document the distribution and sources of particulate and dissolved organic carbon (POC, DOC) as well as dissolved inorganic carbon (DIC). The Betsiboka was characterized by a relatively high suspended matter load, and in line with this, low DOC/POC ratios (0.4–2.5). The partial pressure of CO2 (pCO2) was generally above atmospheric equilibrium (270–1530 ppm), but relatively low in comparison to other tropical and subtropical estuaries, resulting in low average CO2 emission to the atmosphere (9.1 ± 14.2 mmol m−2 d−1). Despite the fact that C4 vegetation is reported to cover >80% of the catchment area, stable isotope data on DOC and POC suggest that C4 derived material comprises only 30% of both pools in the freshwater zone, increasing to 60–70% and 50–60%, respectively, in the oligohaline zone due to additional lateral inputs. Sediments from intertidal mangroves in the estuary showed low organic carbon concentrations (<1%) and δ13C values (average −19.8‰) consistent with important inputs of riverine imported C4 material. This contribution was reflected in δ13C signatures of bacterial phospholipid derived fatty acids (i + a15:0), suggesting the potential importance of terrestrial organic matter sources for mineralization and secondary production in coastal ecosystems. 相似文献
39.
Geospeedometry allows to estimate the cooling rate (sinit) of metamorphic rocks at the beginning of the cooling history using diffusion data. But the choice of a diffusion activation energy (E) and a preexponential factor (D0) from experimental results can be difficult. We propose a method to obtain E directly from the rock itself by studying the variation of the average concentration of elements or isotopes (〈C〉) as a function of mineral grain size (d). An appropriate value of D0 can then be estimated using an existing compensation rule, a linear relationship between log D0 and E. Consequently, uncertainties on sinit are markedly reduced. All parameters of this analytical model and their sensitivity on sinit can be estimated from 〈C〉 of the mineral grains under study. As a test we apply our model to a study by Edwards and Valley (1998)**** on 18O/16O fractionation between diopside and calcite in Adirondacks marbles, and find a cooling rate in agreement with previous works, without choosing experimental values for E and D0. 相似文献
40.
Douglas A. Simons Paola Amico Dietrich Baade Sam Barden Randall Campbell Gert Finger Kirk Gilmore Roland Gredel Paul Hickson Steve Howell Norbert Hubin Andreas Kaufer Ralf Kohley Philip MacQueen Sergej Markelov Mike Merrill Satoshi Miyazaki Hidehiko Nakaya Darragh O'Donoghue Tino Oliva Andrea Richichi Derrick Salmon Ricardo Schmidt Hongjun Su Simon Tulloch Maria Luisa García Vargas R. Mark Wagner Olivier Wiecha Binxun Ye 《Experimental Astronomy》2005,19(1-3):15-44
Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 109 pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors – something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future. 相似文献