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Sample records for island aeolian archipelago

  1. Looking inside the Panarea Island (Aeolian Archipelago, Italy by gravity and magnetic data

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    F. Greco

    2008-06-01

    Full Text Available In this paper we show and discuss the results of gravity and magnetic surveys of Panarea Island and its archipelago. The most recent volcanic manifestation occurred in November 2002 with a shallow submarine gas eruption between the islets of Dattilo, Panarelli, Lisca Bianca, Bottaro and Lisca Nera. Currently, the activity of Panarea is monitored through a multidisciplinary study under the umbrella of the Italian Department of Civil Protection with the goal of defining the hazard of this area. With this aim, in May 2006 the first gravity and magnetic surveys of Panarea Island and its archipelago were performed. The offshore magnetic data were obtained using a marine magnetometer, a Geometrics G880, from the Istituto Idrografico dell Marina (IIM. Onshore and offshore magnetic data were integrated into an unique dataset for complete magnetic coverage of the study area. By using two micro-gravimeters (LaCoste & Romberg, gravity data were collected along tracks every 250 meters. The gravity dataset was processed using the standard method. A Bouguer reduction was applied to the free-air gravity dataset using a detailed digital elevation model of the island and the neighbouring sea after evaluation of the optimal Bouguer density to reduce the topographic effect. The result is a Bouguer anomaly map that shows lateral variations in density distribution and the relationships between the shallow volcanic/crustal features and tectonic lineaments. This evidence is also highlighted by the magnetic pattern, which suggests the importance of the youngest volcanic deposits with respect to the magnetic features of the island.

  2. Multicriteria analysis as a tool to investigate compatibility between conservation and development on Salina Island, Aeolian Archipelago, Italy

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    Bodini, Antonio; Giavelli, Giovanni

    1992-09-01

    Several multicriteria evaluation techniques have been developed since the 1970s. The need to compare different territorial policies has justified their introduction into environmental research. These methods are based on the numerical manipulation of heterogeneous information, which varies in terms of reference scale and type of measure (continuous, ordinal, qualitative, binary, etc.). During recent years, diverse investigations have focused on general conditions on Salina, the “green island” of the Aeolian archipelago. Such studies, within an interdisciplinary project, aimed to explore the possibility of implementing conservation strategies that are compatible with human needs, landscape preservation, and sustainable economic development. Three different evaluation techniques are applied, namely multicriteria weighted concordance and discordance analysis and a qualitative procedure. They are used to compare four alternative plans for the socioeconomic development of Salina Island. These plans lie between extreme alternatives: total protection of natural resources and maximizing economic development based on tourism. The plans are compared to each other on the basis of 14 criteria that reflect the socioenvironmental perception of Salina's inhabitants. The approach used in this research seems particularly fruitful because of its flexibility: it offers decision makers the chance to manage heterogeneous data and information that is not easily quantifiable. Such “soft” information helps to evaluate environmental conditions more precisely, and to make a less damaging choice among alternative development plans.

  3. Hawaiian Island Archipelago

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    1985-01-01

    The entire Hawaiian Island Archipelago (21.5N, 158.0W) is seen in this single view. The islands are a favorite international resort and tourist attraction drawing visitors from all over the world to enjoy the tropical climate, year round beaches and lush island flora. Being volcanic in origin, the islands' offer a rugged landscape and on the big island of Hawaii, there is still an occasional volcanic eruption of lava flows and steam vents.

  4. Behaviour of volcanogenic S-bearing compounds (H2S and SO2) in air at Vulcano Island (Aeolian Archipelago, southern Italy)

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    Caponi, Chiara; Tassi, Franco; Ricci, Andrea; Capecchiacci, Francesco; Venturi, Stefania; Cabassi, Jacopo; Vaselli, Orlando

    2017-04-01

    The main sources of SO2 and H2S in air consist of both natural fluid emissions related to active/quiescent volcanoes and hydrothermal systems, and anthropogenic activities (e.g. gas and oil refineries, steel industries, urban traffic). These gas compounds have a strong impact on air quality, since they are strong toxic and climate forcing agents. Notwithstanding, the behaviour of these S-compounds in air once they are released from the contaminant source(s) is poorly known, due to the scarce available data from thermodynamics and direct measurements. Hydrogen sulfide is considered to be relatively reactive in the atmosphere, being easily oxidized to SO2 by photochemical reactions, even though the efficiency of the H2S to SO2 conversion is significantly lowered under dark, dry and relatively cold conditions, leading to a residence time of H2S in air up to 42 days in winter. In this work, H2S and SO2 measurements in air carried out at the Levante beach (Vulcano Island, Aeolian Archipelago), where a number of hydrothermal fluid discharges consisting of fumaroles and submarine emissions occur, are presented and discussed. These volcanic fluids, characterized by an H2S-rich chemical composition, are released in a close proximity to the touristic village of Vulcano Porto. The measurements were carried out using a Thermo Scientific™ Model 450i Analyzer coupled with a Davis® Vantage Vue weather station (air humidity and temperature, wind direction and speed) in 34 fixed spots and along 8 pathways, selected according to: (i) distance from the contaminant source, (ii) wind direction and (iii) accessibility by car (where the instrument was installed). The main aim was to provide empirical insights on the behavior of these air pollutants in relation to the physical and chemical processes controlling their spatial distribution. The measured data were elaborated using a statistical approach to construct spatial distribution maps and conceptual models able to forecast the

  5. Seismicity Pattern Changes before the M = 4.8 Aeolian Archipelago (Italy) Earthquake of August 16, 2010

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    2014-01-01

    We investigated the seismicity patterns associated with an M = 4.8 earthquake recorded in the Aeolian Archipelago on 16, August, 2010, by means of the region-time-length (RTL) algorithm. This earthquake triggered landslides at Lipari; a rock fall on the flanks of the Vulcano, Lipari, and Salina islands, and some damages to the village of Lipari. The RTL algorithm is widely used for investigating precursory seismicity changes before large and moderate earthquakes. We examined both the spatial and temporal characteristics of seismicity changes in the Aeolian Archipelago region before the M = 4.8 earthquake. The results obtained reveal 6-7 months of seismic quiescence which started about 15 months before the earthquake. The spatial distribution shows an extensive area characterized by seismic quiescence that suggests a relationship between quiescence and the Aeolian Archipelago regional tectonics. PMID:24511288

  6. The island of Lipari (Aeolian archipelago, Italy). Preliminary distribution and evaluation of the significative elements pertaining to the environmental, floristic and faunistic patrimony; Distribuzione e valutazione preliminare di biotipi, flora e fauna: l'Isola di Lipari (Arcipelago Eoliano)

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    D' Ayala, A. [Parma Univ., Parma (Italy). Dipt. di Scienze Ambientali

    2000-02-01

    The island of Lipari (Italy), with the larger territorial extension and human impact in the Aeolian archipelago, shows a remarkable naturalistic resources richness and it was recently studied with the Italian program Carta della Natura (national law 394/91). In order to identify and prioritize areas for protection planning, are here presented some preliminary results concerning the conservation status, the spatial distribution of habitats of European importance (EU Habitat Directive 43/92), floristic and faunistic elements classified as threatened in Italy (IUCN categories), with reference to the ecological sensibility, anthropic pressure and also the main problems related the natural reserve in way of institution. [Italian] L'articolo presenta uno studio di valutazione ambientale relativo alla distribuzione dei biotipi, della flora e della fauna dell'isola di Lipari, inerente al programma nazionale Carta della Natura (L. 394/91). Vengono discussi alcuni aspetti significativi connessi all'importanza della conservazione degli habitat dell'isola, con riferimento alle problematiche della futura riserva.

  7. MAGMA STORAGE AND ASCENT AT LIPARI ISLAND (AEOLIAN ARCHIPELAGO, SOUTHERN ITALY) DURING THE OLD STAGES (223-81 KA): ROLE OF CRUSTAL PROCESSES AND TECTONIC INFLUENCE

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    di Martino, C.; Frezzotti, M.; Lucchi, F.; Peccerillo, A.; Tranne, C. A.; Diamond, L.

    2009-12-01

    Fluid inclusion study, together with structural, volcanological and petrochemical data, allow reconstruction of the magma feeding system of basaltic-andesitic to andesitic volcanoes during the oldest and intermediate stages of development of Lipari Island (223-81 ka). A major magma storage zone is active during the overall investigated time span at depths of ~22 km close to the crust-mantle Moho transition, at which mantle-derived mafic magmas tend to accumulate due to neutral buoyancy conditions. A shallow magma reservoir is found at depths of 5.5-3.5 km in correspondence of a major lithological discontinuity within the upper crust beneath central-type volcanoes (M. Mazzacaruso, M. S.Angelo, M. Chirica-Costa d'Agosto). It is the place where magmas shortly rest (day-week time scale) before the eruption. For fissural-type volcanoes (Timpone Ospedale, Monterosa, M. Chirica), tectonic structures are suggested to intercept magma batches at different crustal depths (~14 km), thus provoking CO2-degassing and rapid magma uprising with no substantial ponding at shallow levels. Partial crustal melting processes at roof of the deep magma reservoirs are invoked to explain conditions of fluids trapping at depths of volcanoes, active during the intermediate stages of development of Lipari (105-81 ka). These melting processes determine the generation of felsic melts which may act as a density-barrier and prevent the uprising of mantle-derived magmas, with an influence on the subsequent evolution of the magma feeding system of Lipari.

  8. Magma storage and ascent at Lipari Island (Aeolian archipelago, Southern Italy) at 223-81 ka: the role of crustal processes and tectonic influence

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    di Martino, Corrado; Frezzotti, Maria Luce; Lucchi, Federico; Peccerillo, Angelo; Tranne, Claudio A.; Diamond, Larryn W.

    2010-11-01

    Fluid inclusion studies together with volcanological and petrochemical data allow reconstruction of the magma feeding system of basaltic-andesitic to andesitic activity during the oldest and intermediate stages of development of Lipari Island (223-81 ka). A major magma storage zone is active during the overall investigated time span at depths of 22 km, close to the crust-mantle Moho transition, at which mantle-derived mafic magmas tend to accumulate due to neutral buoyancy conditions. Beneath central-type volcanoes (M. Mazzacaruso, M. S.Angelo, M. Chirica-Costa d’Agosto), a shallower magma reservoir is located within the upper crust at 5.5-3.5 km, associated with a major lithological discontinuity. For fissural-type volcanoes (Timpone Ospedale, Monterosa, M. Chirica), tectonic structures are suggested to influence further magma ascent and storage at mid-crustal depths (˜14 km), with no ponding at shallower levels. Partial crustal melting processes at the roofs of the deep magma reservoirs (˜17 km) are invoked to explain the origin of cordierite-bearing lavas beneath M. S.Angelo and M. Chirica-Costa d’Agosto volcanoes, which were active during the intermediate stages of development of Lipari (105-81 ka). The generation of felsic anatectic melts in the lower crust could have created density and rheologic barriers to impede the passage of mafic melts and promote their ponding, with influence on the subsequent evolution of Lipari volcano.

  9. Effects of steam-heating processes on a stratified volcanic aquifer: Stable isotopes and dissolved gases in thermal waters of Vulcano Island (Aeolian archipelago)

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    Federico, C.; Capasso, G.; Paonita, A.; Favara, R.

    2010-05-01

    We report on a comprehensive study of major-ion chemistry, dissolved gases, and stable isotopes measured in water wells at Vulcano Island since 1988. The work focuses on a quantitative model describing steam condensation and boiling phenomena in shallow water bodies. The model is based on the differences in partition coefficients between liquid water and vapor characterizing oxygen and hydrogen isotopes, as well as volcanic gases (CO 2, S species, and HCl). Based on both physical conditions of aquifers identified during drilling campaigns and the composition of the volcanic vapor, mass and enthalpy balances are applied in a multistep process of steam separation and condensation in shallower aquifers. By comparing the model results with measured data, we infer that (i) strong isotope enrichment observed in some shallow thermal waters can result from an increasing mass rate of condensing deep vapor, even in water meteoric in origin; (ii) the high CO 2 content measured in the fumarolic vapor during 1988-1993 affected the δ18O value of the steam-heated water due to CO 2-H 2O isotope exchange; (iii) the high pCO 2 measured in the coldest and peripheral waters are explained by the progressive enrichment of this gas in the vapor phase during multistep boiling; and (iv) the high Cl - and SO 42-contents in the hottest waters can be attributed to the direct condensation (single-step) of volcanic vapor. The model also takes into account both the mass fluxes and the compositions of the involved endmembers (steam and shallow groundwater), which provides important inferences on the modifications observed or expected during periods of increasing mass and heat input from depth.

  10. Tectonic Influence on Magma Storage and Ascent During the Older Evolutionary Stages (223-105 ka) of the Lipari Island (Aeolian Archipelago, Southern Italy)

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    di Martino, C.; Frezzotti, M.; Lucchi, F.; Peccerillo, A.; Tranne, C.; Diamond, L.

    2008-12-01

    Pure CO2 fluid inclusions are observed in fifteen quartz-rich xenoliths collected in basaltic-andesitic to andesitic volcanic products relevant to the older evolutionary stages of Lipari Island (223-105 ka). In volcanics forming central composite volcanoes (M. Mazzacaruso, 223-127 ka; M. S.Angelo, 105 ka), fluid inclusions are trapped during two distinct events: early Type I inclusions formed before host magma transport, and late (i.e. secondary) Type II inclusions trapped during magma ascent. Early Type I inclusions show homogenization temperatures corresponding to densities from 0.9 to 0.6 g/cc, while Type II inclusions record a considerably lower density interval between 0.38 and 0.1 g/cc. At the estimated trapping temperatures between 950 and 1090°C, obtained density values correspond to pressures of 0.58- 0.25 GPa (22-10 km) for Type I, and 0.13-0.03 GPa (5.5-1 km) for Type II inclusions, respectively. In those magmas erupted from fissural eruptive vents aligned along the main regional NNW-SSE and E-W faults systems (Timpone Ospedale, Monterosa and M. Chirica; 223-127 ka) only early Type I inclusions are observed. Density values form to two distinct intervals between 0.87 and 0.6 g/cc (0.53-0.25 GPa; 20-10 km; M. Chirica), and between 0.68-0.18 g/cc (0.32-0.05 GPa; 12-2 km; Timpone Ospedale and Monterosa). Fluid inclusion data together with tectonic features outline a complex magma storage and ascent evolution during the Lipari's older evolutionary stages. Beneath the central volcanoes of M. Mazzacaruso, M. S.Angelo and the M. Chirica, two magma reservoirs, located at lower crustal depths (~22 km; close to the Moho) and at very shallow levels (5.5-1 km), are present. Mantle-Derived magmas are accumulated into the deep magma chamber and may then reside in the shallower reservoir for a short period of time before being erupted to the surface. Such a magma feeding system is similar to those outlined for the Alicudi and Stromboli volcanoes, and for most of the

  11. Island Movements: Thinking with the Archipelago

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    Jonathan Pugh

    2013-05-01

    Full Text Available Whether in Homer or Plato, Shakespeare or Huxley, throughout history, thinking about islands has shaped how we think about human nature and our place in the world. However, to date archipelagos have received far less attention. This is problematic because we live, increasingly, in a world of island-island movements and not static forms. Not only in the more obvious cases of the Caribbean, Hawaii or the Philippines but, as Stratford et al (2011 say, many ‘continental forms’ like Canada and Australia are in fact archipelagos composed of thousands of island movements. To this list we can add more manufactured archipelagos: wind turbine arrays, industrial oil and military constellations. The key question therefore arises: what does it mean to think with the archipelago? This paper argues firstly that archipelagic thinking denaturalizes the conceptual basis of space and place, and therefore engages ‘the spatial turn’ presently sweeping the social sciences and humanities. Secondly, such thinking highlights the trope of what I call ‘metamorphosis’, of the adaptation and transformation of material, cultural and political practices through island movements. In both cases, I argue that thinking with the archipelago requires an important shift in how we frame analysis and engagement.

  12. A morphometric model of the Aeolian Islands (Italy)

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    Bisson, M.; Favalli, M.; Mazzarini, F.; Mori, A.; Sinapi, M. T. Pareschi   L.

    2003-07-01

    A Digital Elevation Model (DEM) of the Aeolian Islands (Southern Tyrrhenian Sea, Italy) is presented, with a 5 m horizontal resolution, derived from photograms at a relative medium scale of 1:35000, collected during an aerophotogrammetric flight in 1994-5. The sea data come from a hydrographic survey (1996-1997) of the seabed topography, carried out in accordance with present international standards. The sounding density of the bathymetric survey varies: it is more accurate near the coasts and in areas of structural interest. Previous bathymetric surveys, when available, were limited to small areas. The present DEM is enclosed in a rectangle with limits of longitude 14°16'32”- 15°22'51”E and latitude 38°20'55”- 38°53'50”N. The DEM of the islands and of the seabed, merged together, is presented here for the first time. The shadowed raster images of the DEM clearly outline the structural and volcanological features of the archipelago.

  13. New insights from high resolution bathymetric surveys in the Panarea volcanic complex (Aeolian Islands, Italy)

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    Anzidei, M.; Esposito, A.

    2003-04-01

    During November 2002 the portion of the Panarea volcanic complex (Aeolian Islands, Italy), which includes the islets of Dattilo, Panarelli, Lisca Bianca, Bottaro and Lisca Nera, experienced an intense submarine gaseous exhalation that produced a spectacular submarine fumarolic field. The submarine volcanic activity of the Aeolian area was already known during historical times by Tito Livio, Strabone and Plinio (SGA, 1996), that reported exhalation episodes and submarine eruptions. During the last decade geological, structural, geochemical and volcanological studies performed on the Panarea volcanic complex, evidenced a positive gravimetric anomaly, tectonic discontinuities and several centres of geothermal fluid emission (Barberi et al., 1974; Lanzafame and Rossi, 1984; Bellia et al., 1986; Gabianelli et al., 1990; Italiano and Nuccio, 1991; Calanchi et al., 1995,1999). With the aim to estimate the crustal deformation of the submarine area of the archipelago, connected with the exhalation activity, we produced a detailed Marine Digital Terrain Model (MDTM) of the seafloor by means of a high resolution bathymetric survey. We used the multi beam technique coupled with GPS positioning in RTK mode. We obtained a MDTM with an average pixel of 0.5 m. Our MDTM allowed to estimate the location, deep, shape and size of the exhalation centres and seafloor morphological-structural features, opening new questions for the evaluation of the volcanic hazard of Panarea area which date is still debated.

  14. Palaeoclimatic considerations of talus flatirons and aeolian deposits in Northern Fuerteventura volcanic island (Canary Islands, Spain)

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    Gutiérrez-Elorza, Mateo; Lucha, Pedro; Gracia, F.-Javier; Desir, Gloria; Marín, Cinta; Petit-Maire, Nicole

    2013-09-01

    Fuerteventura volcanic island has been subject to considerable aeolian activity since the Late Pleistocene. The aeolian record includes inactive aeolian deposits with interbedded entisols, whose age by OSL dating ranges between 46 and 26 ky BP. The Corralejo active dune field, where sand sheets, nebkhas, coppice dunes, blowouts, barchans and transverse dunes have been described, constitutes a more recent Aeolian deposit. Here the age is about 14 ky BP. On Fuerteventura Island aeolian dust has been deposited on valleys and slopes. This last type of accumulation has been affected by gully incision, producing talus flatirons. Samples taken on the apex of these palaeo-slopes indicate an OSL age of 30 and 50 ky BP. A palaeoclimatic succession has been interpreted during which a prevailing arid period took place in OIS 4, with the accumulation of aeolian dust. A humid period occurred in OIS 2, during which slopes were dissected and formed talus flatirons. An arid period about 14 ky BP gave rise to the Corralejo dune field, which has continued until present with slight climatic oscillations.

  15. The Idea of the Archipelago: Contemplating Island Relations

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    Elaine Stratford

    2013-05-01

    Full Text Available Creative, innovative, and timely research on islands and island futures is warranted and pressing, not least because island(ers are poorly served by established tropes of them as subordinate to continents or mainlands. Opportunities exist to provide a more thoroughgoing account of island life and island relations, and the seven papers in this special issue address that task. In works that consider islands in the Timor Sea, the Caribbean, the Pacific, Atlantic and Southern Oceans, and that span several different disciplinary frames—archival-historical, critical theoretical, literary, cultural, geopolitical, sociological and artistic—these papers evidence both the diversity of approach to thinking with the archipelago, and numerous points in common. Among the latter is an understanding that island relations are built on connection, assemblage, mobility, and multiplicity, and a commitment to critically examine the ways in which these entanglements affect and give effect to island life. The models of island relationality brought to light by this collective focus on the archipelago reveal new and diverse connections of island peoples with their physical and cultural environments, and with the world beyond; create spaces for growing resilience, association and engagement; and invite further study.

  16. Palaeomagnetism of welded, pyroclastic-fall scoriae at Vulcano, Aeolian Archipelago

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    Zanella, E.; De Astis, G.; Lanza, R.

    2001-06-01

    This paper deals with the magnetic fabric and remanent magnetization of welded scoriae fall deposits. Four scoriae blankets were emplaced on Vulcano (Aeolian Islands) from about 50 to 8 ka. Their detailed chronostratigraphic position has been debated in the literature and they have therefore been given a different interpretation in the reconstruction of the Vulcano's eruptive history. The aims of the study were a better understanding of the magnetic features of the scoriae fall deposits, which have so far been given little attention, and to set the chronostratigraphic relationships of the sampled deposits on the ground of their palaeomagnetic directions. Overall, the magnetic properties of the four deposits are alike. Investigation of isothermal remanence and susceptibility versus temperature measurements point to low-Ti titanomagnetite as the main ferromagnetic mineral. Magnetic foliation is well developed, moderately dispersed and in most cases close to horizontal. Lineation is either clustered or dispersed within the foliation plane. Stepwise thermal and alternating field demagnetization shows that secondary components are negligible in two units. In the other two, they are always completely removed in the first steps, below 20 mT or 400°C. Thereafter, the characteristic component (ChRM) is clearly isolated and the within-site dispersion of its direction is small ( α95fabric and remanence shows that no en masse movement of welded scoria occurred nor did individual spatter move with respect to one another after their emplacement. The scoriae therefore welded and cooled in situ. The between-site dispersion of the ChRM directions also is very small ( α95<3.5°) for three units, and their mean palaeomagnetic direction is consistent with the palaeosecular variation curve for Aeolian Islands. Statistical analysis of the results from two units whose isotopic ages are indistinguishable within the error range (Quadrara: 21.3±2.4 ka; Spiaggia Lunga: 24.0±5.0 ka

  17. Bronze Age pottery from the Aeolian Islands: definition of Temper Compositional Reference Units by an integrated mineralogical and microchemical approach

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    Brunelli, D.; Levi, S. T.; Fragnoli, P.; Renzulli, A.; Santi, P.; Paganelli, E.; Martinelli, M. C.

    2013-12-01

    An integrated microchemical-petrographic approach is here proposed to discriminate the provenance of archaeological pottery artefacts from distinct production centres. Our study focuses on a statistically significant sampling ( n=186) of volcanic temper-bearing potteries representative of the manufacturing and dispersion among the islands of the Aeolian Archipelago during the Bronze Age. The widespread establishment of new settlements and the abundant recovery of Aeolian-made ceramic in southern Italy attest for the increased vitality of the Archipelago during the Capo Graziano culture (Early Bronze Age-Middle Bronze Age 2; 2300-1430 BC). Potteries from three of the main known ancient communities (Lipari, Filicudi and Stromboli) have been studied integrating old collections and newly excavated material. Volcanic tempers have been first investigated through multivariate analyses of relative abundances of mineral and rock clasts along with petrographic characters. In addition, we performed in-situ mineral chemistry microanalyses by Electron Microprobe and Laser Ablation—Inductively Coupled Plasma Mass Spectrometry to assess major and trace element composition of the most common mineral phases. Four Temper Compositional Reference Units have been recognised based on compositional trends. Two units (AI and AX) are unequivocally distinct by their peculiar trace element enrichment and petrographic composition; they mostly contain samples from the sites of Lipari and Stromboli, respectively. Units AIV and AVIII, restricted to the sites of Filicudi and Stromboli, show distinct petrographic characters but overlapped geochemical fingerprints.

  18. Aeolian processes and landforms in the sub-Antarctic: preliminary observations from Marion Island

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    David W. Hedding

    2015-11-01

    Full Text Available Sub-Antarctic Marion Island has a hyperoceanic climate, with cold and wet conditions and consistently strong wind velocities throughout the year. Recent observations recognized the increasing role of aeolian processes as a geomorphic agent, and this paper presents the first data for transport by aeolian processes on a sub-Antarctic island. Data were collected through an intensive and high-resolution measurement campaign at three study sites using Big Spring Number Eight sediment traps and surface sediment samplers in conjunction with an array of climatic and soil logger sensors. Observed aeolian landforms are megaripples, and the data suggest that aeolian processes are also modifying solifluction landforms. The sediment traps and sediment samplers collected wind-blown scoria at all three study sites, and the annual (horizontal aeolian sediment flux extrapolated from this preliminary data is estimated at 0.36–3.85 kg cm−2 y−1. Importantly, plant material of various species was trapped during the study that suggests the efficiency of wind for the dispersal of plants in this sub-Antarctic environment may be underestimated. This paper advocates long-term monitoring of aeolian processes and that the link between aeolian processes and synoptic climate must be established. Furthermore, wind as a means to disperse genetic material on Marion Island should be investigated.

  19. Erupted cumulate fragments in rhyolites from Lipari (Aeolian Islands)

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    Forni, Francesca; Ellis, Ben S.; Bachmann, Olivier; Lucchi, Federico; Tranne, Claudio A.; Agostini, Samuele; Dallai, Luigi

    2015-12-01

    Over the last ~267 ky, the island of Lipari has erupted magmas ranging in compositions from basaltic andesites to rhyolites, with a notable compositional gap in the dacite field. Bulk geochemical and isotopic compositions of the volcanic succession, in conjunction with major and trace elemental compositions of minerals, indicate that the rhyolites were dominantly generated via crystal fractionation processes, with subordinate assimilation. Radiogenic (Sr, Nd, and Pb) and stable (O) isotopes independently suggest ≤30 % of crustal contamination with the majority of it occurring in mafic compositions, likely relatively deep in the system. Within the rhyolites, crystal-rich, K2O-rich enclaves are common. In contrast to previous interpretations, we suggest that these enclaves represent partial melting, remobilization and eruption of cumulate fragments left-over from rhyolite melt extraction. Cumulate melting and remobilization is supported by the presence of (1) resorbed, low-temperature minerals (biotite and sanidine), providing the potassic signature to these clasts, (2) reacted Fo-rich olivine, marking the presence of mafic recharge, (3) An38-21 plagioclase, filling the gap in feldspar composition between the andesites and the rhyolites and (4) strong enrichment in Sr and Ba in plagioclase and sanidine, suggesting crystallization from a locally enriched melt. Based on Sr-melt partitioning, the high-Sr plagioclase would require ~2300 ppm Sr in the melt, a value far in excess of Sr contents in Lipari and Vulcano magmas (50-1532 ppm) but consistent with melting of a feldspar-rich cumulate. Due to the presence of similar crystal-rich enclaves within the rhyolites from Vulcano, we propose that the eruption of remobilized cumulates associated with high-SiO2 rhyolites may be a common process at the Aeolian volcanoes, as already attested for a variety of volcanic systems around the world.

  20. The western Aeolian Islands volcanoes (Southern Tyrrhenian Sea, Italy) : the temporal and chemical evolution of a complex magmatic system

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    Leocat, E.; Peccerillo, A.; Gillot, P.-Y.

    2012-04-01

    The Aeolian Archipelago is located on the northern continental margin of the Calabro-Peloritan basement. This volcanic province emplaces in the geodynamic system linked to the convergence of African and European plates. In this study, we focused on Alicudi, Filicudi, Salina, Lipari and Vulcano to understand the temporal and geochemical evolution of western Aeolian Islands magmatism. These volcanoes contain the whole geochemical compositions typical of convergence settings ranging from calc-alkaline (CA) and high-K CA (HKCA) to shoshonitic (SHO) and potassic rocks (KS). Moreover, these magmas were emitted over a short time span, which attests to the complexity of the geodynamical setting. Geochemical data, consisting in major and trace elements whole rock analysis, were carried out on dated samples, whose geochronological data are based on K-Ar technique. The first magmas, emitted at Filicudi, Salina and Lipari after 300 ka, have relatively the same CA composition, whereas some Lipari lavas have early HKCA affinity. Around 120-130 ka, Alicudi and Vulcano emerged simultaneously in the western and central volcanic province that is influenced by two contrasted magmatic systems. In fact, the SHO magmatism in the central sector is coeval with CA activity in the western arc. After 40 ka, the last activity of Filicudi consists of mafic magmas of HKCA affinity while Salina and Alicudi emitted CA products. In contrast, mainly differentiated magmas of HKCA-SHO affinity were emplaced at Lipari and Vulcano. Overall, the K and incompatible elements enrichments increase through time mostly in the central arc. At the scale of the archipelago, the magmatic changes occurring around 120 and 40 ka may be explained by deep and regional processes, as mantle source contamination variations. However, at smaller space and time-scales, the magmatic evolution is more complex reflecting peculiar processes, as crustal assimilation and fractional crystallisation, specific to each volcano

  1. Perspective View, Mt. Etna, Italy & the Aeolian Islands

    Science.gov (United States)

    2002-01-01

    Italy's Mount Etna and the Aeolian Islands are the focus of this perspective view made from an Advanced Spaceborne Thermal and Emission Radiometer (ASTER) image from NASA's Terra spacecraft overlaid on Shuttle Radar Topography Mission (SRTM) topography. The image is looking south with the islands of Lipari and Vulcano in the foreground and Etna with its dark lava flows on the skyline. Vulcano also hosts an active volcano, the cone of which is prominent. In late October 2002, Etna erupted again, sending lava flows down the north and south sides of the volcano. The north flows are near the center of this view, but the ASTER image is from before the eruption.In addition to the terrestrial applications of these data for understanding active volcanoes and hazards associated with them such as lava flows and explosive eruptions, geologists studying Mars find these data useful as an analog to martian landforms and geologic processes. In late September 2002, a field conference with the theme of Terrestrial Analogs to Mars focused on Mount Etna allowing Mars geologists to see in person the types of features they can only sample remotely.Elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D

  2. Landslides density map of S. Miguel Island, Azores archipelago

    Directory of Open Access Journals (Sweden)

    P. Valadão

    2002-01-01

    Full Text Available The Azores archipelago is located in the Atlantic Ocean and is composed of nine volcanic islands. S. Miguel, the largest one, is formed by three active, E-W trending, trachytic central volcanoes with caldera (Sete Cidades, Fogo and Furnas. Chains of basaltic cinder cones link those major volcanic structures. An inactive trachytic central volcano (Povoação and an old basaltic volcanic complex (Nordeste comprise the easternmost part of the island. Since the settlement of the island early in the 15th century, several destructive landslides triggered by catastrophic rainfall episodes, earthquakes and volcanic eruptions occurred in different areas of S. Miguel. One unique event killed thousands of people in 1522. Houses and bridges were destroyed, roads were cut, communications, water and energy supply systems became frequently disrupted and areas of fertile land were often buried by mud. Based on (1 historical documents, (2 aerial photographs and (3 field observations, landslide sites were plotted on a topographic map, in order to establish a landslide density map for the island. Data obtained showed that landslide hazard is higher on (1 the main central volcanoes where the thickness of unconsolidated pyroclastic deposits is considerable high and (2 the old basaltic volcanic complex, marked by deep gullies developed on thick sequences of lava flows. In these areas, caldera walls, fault scarps, steep valley margins and sea cliffs are potentially hazardous.

  3. Landslides density map of S. Miguel Island, Azores archipelago

    Science.gov (United States)

    Valadão, P.; Gaspar, J. L.; Queiroz, G.; Ferreira, T.

    The Azores archipelago is located in the Atlantic Ocean and is composed of nine volcanic islands. S. Miguel, the largest one, is formed by three active, E-W trending, trachytic central volcanoes with caldera (Sete Cidades, Fogo and Furnas). Chains of basaltic cinder cones link those major volcanic structures. An inactive trachytic central volcano (Povoação) and an old basaltic volcanic complex (Nordeste) comprise the easternmost part of the island. Since the settlement of the island early in the 15th century, several destructive landslides triggered by catastrophic rainfall episodes, earthquakes and volcanic eruptions occurred in different areas of S. Miguel. One unique event killed thousands of people in 1522. Houses and bridges were destroyed, roads were cut, communications, water and energy supply systems became frequently disrupted and areas of fertile land were often buried by mud. Based on (1) historical documents, (2) aerial photographs and (3) field observations, landslide sites were plotted on a topographic map, in order to establish a landslide density map for the island. Data obtained showed that landslide hazard is higher on (1) the main central volcanoes where the thickness of unconsolidated pyroclastic deposits is considerable high and (2) the old basaltic volcanic complex, marked by deep gullies developed on thick sequences of lava flows. In these areas, caldera walls, fault scarps, steep valley margins and sea cliffs are potentially hazardous.

  4. Applying and validating the PTVA-3 Model at the Aeolian Islands, Italy: assessment of the vulnerability of buildings to tsunamis

    Directory of Open Access Journals (Sweden)

    F. Dall'Osso

    2010-07-01

    Full Text Available The volcanic archipelago of the Aeolian Islands (Sicily, Italy is included on the UNESCO World Heritage list and is visited by more than 200 000 tourists per year. Due to its geological characteristics, the risk related to volcanic and seismic activity is particularly high. Since 1916 the archipelago has been hit by eight local tsunamis. The most recent and intense of these events happened on 30 December 2002. It was triggered by two successive landslides along the north-western side of the Stromboli volcano (Sciara del Fuoco, which poured approximately 2–3×107 m3 of rocks and debris into the Tyrrhenian Sea. The waves impacted across the whole archipelago, but most of the damage to buildings and infrastructures occurred on the islands of Stromboli (maximum run-up 11 m and Panarea.

    The aim of this study is to assess the vulnerability of buildings to damage from tsunamis located within the same area inundated by the 2002 event. The assessment is carried out by using the PTVA-3 Model (Papathoma Tsunami Vulnerability Assessment, version 3. The PTVA-3 Model calculates a Relative Vulnerability Index (RVI for every building, based on a set of selected physical and structural attributes. Run-up values within the area inundated by the 2002 tsunami were measured and mapped by the Istituto Italiano di Geofisica e Vulcanologia (INGV and the University of Bologna during field surveys in January 2003. Results of the assessment show that if the same tsunami were to occur today, 54 buildings would be affected in Stromboli, and 5 in Panarea. The overall vulnerability level obtained in this analysis for Stromboli and Panarea are "average"/"low" and "very low", respectively. Nonetheless, 14 buildings in Stromboli are classified as having a "high" or "average" vulnerability. For some buildings, we were able to validate the RVI scores calculated by the PTVA-3 Model through a qualitative comparison with photographs taken by INGV and

  5. Geology, petrography, and petrology of Pinzon Island, galapagos archipelago

    Science.gov (United States)

    Baitis, Hartmut W.; Lindstrom, Marilyn M.

    1980-06-01

    Three stratigraphic units based on geologic relationships and paleomagnetic observations may be distinguished on Pinzon Island. The oldest unit is a broad shield which forms the main body of the island and was erupted during a period of reversed magnetic polarity from an area now occupied by a caldera. Subsequent activity was centered about 1.5 km to the north-northwest from vents later engulfed by the collapse of a younger caldera. The lower portion of this sequence was erupted during a period of transitional pole positions and is overlain by flows of normal polarity. Pinzon has the most diverse suite of differentiated tholeiitic rocks found in the Galapagos Archipelago. Products of eruptive cycles are preserved as sequences of tuffs and flows that have decreasing degrees of differentiation and increasing phenocryst abundance upsection. The sequences may be a consequence of tapping successively deeper levels of compositionally zoned magma chambers. Such a model is consistent with computer calculations utilizing major and trace element data for Pinzon rocks, which suggest that lavas of the island may be related by shallow-level crystal fractionation of observed phenocryst minerals.

  6. The western Aeolian Islands volcanoes (South Tyrrhenian Sea): highlight on their eruptive history based on K-Ar dating.

    Science.gov (United States)

    Leocat, E.; Gillot, P.-Y.; Peccerillo, A.

    2012-04-01

    The Aeolian Islands volcanoes are located in southern Tyrrhenian Sea on the northern continental margin of the Calabro-Peloritan basement. The Stromboli, Panarea and Vulcano volcanoes of the half eastern sector are well studied as they are still active and they represent high volcanic hazard. While stratigraphic studies were carried out on volcanoes of the western sector, radiometric ages are lacking to well understand their eruptive history. Therefore, new geochronological and geochemical data were obtained for Alicudi, Filicudi, Salina and Lipari western volcanoes. The aim is to establish a complete time framework of the volcanism and to study possible time-related variations of magma compositions. The 37 new ages were obtained using K-Ar Cassignol-Gillot technique that is suitable for dating Quaternary volcanic rocks. The new geochemical data consist of whole rock major and trace elements analysis on dated samples. Our new sets of data give evidence that the Aeolian Islands are young volcanoes emplaced within the last 300 ka. The oldest products outcrop at Filicudi, Salina and Lipari. Te first emerged activity of Alicudi volcano occurred 120 ka ago. While quiescence activity of at least 50 ka is recognized at Filicudi and Lipari, and potentially at Salina, the volcanic activity of Alicudi would have been relatively continuous. These whole volcanoes were active within the last 30 ka which has to be considered for volcanic hazard assessment. At the scale of each volcano, the degree of differentiation increase roughly through time, except at Filicudi where the ultimate products correspond to mafic magma. At the scale of the archipelago, this process increases from western Alicudi and Filicudi volcanoes, where andesitic magmas are the most evolved magmas, to central Salina and Lipari volcanoes, where rhyolitic magmas are emitted during explosive eruption. Moreover, pulses of magmatic activity would have occurred around 30-40 and 110-120 ka when the four volcanoes

  7. Applying and validating the PTVA-3 Model at the Aeolian Islands, Italy: assessment of the vulnerability of buildings to tsunami

    Science.gov (United States)

    Dall'Osso, Filippo; Maramai, Alessandra; Graziani, Laura; Brizuela, Beatriz; Cavalletti, Alessandra; Gonella, Marco; Tinti, Stefano

    2010-05-01

    The volcanic archipelago of the Aeolian Islands (Sicily, Italy) is included in the UNESCO World Heritage list and it is visited by more than 200.000 tourists per year. However, because of its geological characteristics, the risk related to the volcanic and seismic activity is particularly high. Since 1916 the archipelago has been hit by 8 local tsunamis (Maramai et al., 2005). The last and most intense of these events happened on the 30th of December 2002. It was triggered by two subsequent landslides along the north side of the Stromboli volcano (Sciara del Fuoco), which poured into the sea about 2-3 x 107 m3 of rocks and debris (Tinti et al., 2005). The waves reached the whole archipelago, but most of the damage to buildings and infrastructures occurred in the island of Stromboli (maximum run-up 11 metres) and Panarea. The aim of this study is to assess the vulnerability of those buildings located within the area inundated in 2002. The assessment is carried out using the PTVA-3 model (Papathoma Tsunami Vulnerability Assessment-version 3), recently developed and applied by Dall'Osso et al. (2009) in Sydney. As the original version of the PTVA (Papathoma, 2003), the PTVA-3 calculates a Relative Vulnerability Index (RVI) for every building, based on a set of selected physical and structural attributes. Run up values within the area inundated by the 2002 tsunami were measured and mapped by INGV and University of Bologna during field surveys in January 2003. Results of the assessment show that if the same tsunami occurred today, 54 buildings would be hit in Stromboli, and 5 in Panarea. The overall vulnerability level obtained for Stromboli is "average"/"low", while "very low" for Panarea. Nonetheless, 13 buildings in Stromboli are classified as having a "high" or "average" vulnerability. For 5 buildings, we could validate the RVI values calculated by the PTVA-3 through a qualitative comparison with some pictures taken by INGV during the post-tsunami survey. Apart from

  8. CRED Reson 8101 multibeam backscatter data from the islands and banks in the Mariana archipelago, 2007.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the Mariana archipelago between the U.S. Territory of Guam and Uracas Island in the Commonwealth...

  9. Viticultural zoning of Graciosa island of the Azores archipelago - Portugal

    Science.gov (United States)

    Madruga, João; Reis, Francisco; Felipe, João; Azevedo, Eduardo; Pinheiro, Jorge

    2016-04-01

    The management and sustainability of the traditional vineyards of the Azores settled on lava field terrains is strongly affected by practical limitations of mechanization and high demand on man labor imposed by the typical micro parcel structure of the vineyards. In a recent macrozoning approach study Madruga et al (2015) showed that besides the traditional vineyards there are significant areas in some of the Azores islands whose soils, climate and physiographic characteristics indicate a potential for the development of new vineyard areas offering conditions for better management and sustainability. The objective of this study was to conduct a detailed viticultural zoning at the level of the small mapscale (smaller than 1:25,000), for the island of Graciosa where, besides the traditional lava field terroir, there are also some localized experiences of grapevine production over normal soils, offering thus some comparative information on this type of production conditions. The zoning approach for the present study was based in a geographic information system (GIS) analysis incorporating factors related to climate and topography which was then combined with the soil mapping units fulfilling the suitable criteria concerning the soil properties taken as the most relevant for viticulture, being the result a map of homogeneous environmental units. The climatic zoning examined the direct quantitative variables (precipitation, temperature, evaporation) in relation to climate index, bioclimatic and viticultural specific values. Topography (elevation, slope, aspect, orientation) was analyzed based on the tridimensional models of the islands in GIS to include the best slopes for the mechanization of the vineyard cultural operations (0-15%). Soils were analyzed based on data and soil map units as defined in the soil surveys of the Azores archipelago. The soil properties taken for the analysis and definition of the potential vineyard areas were drainage, water holding capacity

  10. Accidental and ideal island cities: islanding processes and urban design in Belize City and the urban archipelagos of Europe

    Directory of Open Access Journals (Sweden)

    Elizabeth Pigou-Dennis

    2014-11-01

    Full Text Available This paper explores processes of islanding, de-islanding, and re-islanding in the context of island cities. Although today popularly associated with rural, peripheral, and isolated landscapes, concepts of the ideal city coincided in Medieval and Renaissance Europe with emergent notions of the ideal island. Major European cities such as Amsterdam, Paris, and Copenhagen were established on densely urbanized small islands. In accordance with dominant political and military philosophies, they were subsequently developed through comprehensive urban design into vast yet coherent urban archipelagos. In contrast, the contemporary development of Belize City as an island city took place through piecemeal land reclamation, absent comprehensive urban design, resulting in a very different kind of urban archipelago. Neither the coherent European island cities nor Belize City are generally regarded as islands today, yet their histories of urban development evidence the impact of spatial attributes of islandness on urban form. Comprehensive urban design efforts are currently directed at land reclamation and waterfront revitalization in Belize City, aiming to restore Belize City’s island city status. We argue that cities can be islanded, de-islanded, and re-islanded in the minds of their inhabitants and that it is necessary to recognize the connection between ideal islands and ideal cities in order to understand the islanding process in full.

  11. Phytochemical analysis of Achillea ligustica All. from Lipari Island (Aeolian Islands).

    Science.gov (United States)

    Venditti, Alessandro; Guarcini, Laura; Bianco, Armandodoriano; Rosselli, Sergio; Bruno, Maurizio; Senatore, Felice

    2016-01-01

    A complete chemical investigation of Achillea ligustica All. growing at Lipari (Aeolian Island, Sicily) has been carried out. Seventeen metabolites have been isolated and characterised from dichloromethane and methanol extracts of flowers and aerial parts, and GC/MS analyses of petroleum ether extracts was carried out, revealing a composition in sesquiterpenoids similar to those reported for populations from Greece, Sicily and Algeria, showing the presence of (3RS,6RS)-2,6-dimethyl-1,7-octadiene-3,6-diol (1), 2,6-dimethyl-octa-3(E),7-diene-2,6-diol (2), iso-seco-tanapartholide (3) from DCM fraction. In addition from the methanolic extract of the aerial parts, peculiar flavonoid glucuronides have been isolated: i.e. apigenin-7-O-glucuronide (12) and quercetin 3-O-glucuronide (14). These metabolites have been reported in this species for the first time. The isolated flavonoids were previously recognised in several species of this complex genus and for this reason seems to be highly retained secondary metabolites of importance from the chemotaxonomic point of view.

  12. Littoral Decapods of Socorro Island, Revillagigedo Archipelago, Mexico

    Directory of Open Access Journals (Sweden)

    Silvia Mille-Pagaza

    2003-03-01

    Full Text Available Decapod community inhabiting the rocky littoral of eight bays from Socorro island, Revillagigedo Archipelago, was studied during March 1992. Samples were collected from one-square meter plots placed following transects drawn perpendicularly to the shoreline along the intertidal zone. Species richness and abundance were determined in each bay, as well as the similarity between bays using Morisita’s index. Organisms collected belong to six families, 20 genera and 26 species of the Brachyura and Anomura infraorders. Xanthidae was the family with the highest number of species, and the highest species richness was recorded at the V. Lozano bay. Pachygrapsus transversus, Xanthodius cooksoni and Calcinus explorator were the most abundant species in nearly all localities. Dendrogram obtained define two groups of bays at a similarity level above 0.67, given the similarity in the crab’s species richness and their abundance between bays in the island.Se estudió la comunidad de cangrejos del litoral rocoso de ocho bahías de la Isla Socorro, Archipiélago Revillagigedo en marzo de 1992. Las muestras fueron colectadas en cuadrantes de un m² a lo largo de transectos perpendiculares a la costa en la zona intermareal. Se determinó la riqueza específica, la abundancia por especie para cada bahía, así como la similitud entre bahías mediante el índice de Morisita. Los organismos colectados pertenecen a seis familias, 20 géneros y 26 especies de los infraordenes Brachyura y Anomura. La familia con el mayor número de especies fue Xanthidae y la mayor riqueza específica se registró en la bahía V. Lozano. Pachygrapsus transversus, Xanthodius cooksoni y Calcinus explorator fueron las más abundantes en casi todas las localidades. En el dendrograma se definen dos agrupaciones con nivel de similitud superior a 0.67, dada la semejanza en la riqueza específica de cangrejos y las abundancias entre las bahías.

  13. Archipelago-wide island restoration in the Galapagos Islands: reducing costs of invasive mammal eradication programs and reinvasion risk.

    Directory of Open Access Journals (Sweden)

    Victor Carrion

    Full Text Available Invasive alien mammals are the major driver of biodiversity loss and ecosystem degradation on islands. Over the past three decades, invasive mammal eradication from islands has become one of society's most powerful tools for preventing extinction of insular endemics and restoring insular ecosystems. As practitioners tackle larger islands for restoration, three factors will heavily influence success and outcomes: the degree of local support, the ability to mitigate for non-target impacts, and the ability to eradicate non-native species more cost-effectively. Investments in removing invasive species, however, must be weighed against the risk of reintroduction. One way to reduce reintroduction risks is to eradicate the target invasive species from an entire archipelago, and thus eliminate readily available sources. We illustrate the costs and benefits of this approach with the efforts to remove invasive goats from the Galápagos Islands. Project Isabela, the world's largest island restoration effort to date, removed >140,000 goats from >500,000 ha for a cost of US$10.5 million. Leveraging the capacity built during Project Isabela, and given that goat reintroductions have been common over the past decade, we implemented an archipelago-wide goat eradication strategy. Feral goats remain on three islands in the archipelago, and removal efforts are underway. Efforts on the Galápagos Islands demonstrate that for some species, island size is no longer the limiting factor with respect to eradication. Rather, bureaucratic processes, financing, political will, and stakeholder approval appear to be the new challenges. Eradication efforts have delivered a suite of biodiversity benefits that are in the process of revealing themselves. The costs of rectifying intentional reintroductions are high in terms of financial and human resources. Reducing the archipelago-wide goat density to low levels is a technical approach to reducing reintroduction risk in the short

  14. Genetic affinities between the Yami tribe people of Orchid Island and the Philippine Islanders of the Batanes archipelago

    OpenAIRE

    2011-01-01

    Abstract Background Yami and Ivatan islanders are Austronesian speakers from Orchid Island and the Batanes archipelago that are located between Taiwan and the Philippines. The paternal genealogies of the Yami tribe from 1962 monograph of Wei and Liu were compared with our dataset of non-recombining Y (NRY) chromosomes from the corresponding families. Then mitochondrial DNA polymorphism was also analyzed to determine the matrilineal relationships between Yami, Ivatan, and other East Asian popu...

  15. CRED Simrad em300 multibeam backscatter data from the islands and banks in the Mariana archipelago, 2007.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the Mariana archipelago between the U.S. Territory of Guam and Uracas Island in the Commonwealth...

  16. Pectinoidea (Bivalvia: Propeamussiidae, Entoliidae and Pectinidae) from the Tarava Seamounts, Society Islands and the Tuamotu Archipelago (French Polynesia)

    NARCIS (Netherlands)

    Dijkstra, H.H.; Maestrati, P.

    2013-01-01

    Eighteen species of Pectinoidea (six Propeamussiidae Abbott, 1954, one Entoliidae Teppner, 1922, eleven Pectinidae Rafinesque, 1815) are listed from the Tarava Seamounts, Society Islands and Tuamotu Archipelago, French Polynesia. Four Propeamussiidae species (Parvamussium lamellatum n. sp., Parvamus

  17. Toward a Theory of Island Pedogeography: Testing the driving forces for pedological assemblages in archipelagos of different origins

    Science.gov (United States)

    Ibáñez, Juan-José; Effland, William R.

    2011-12-01

    The Theory of Island Biogeography has been based on biodiversity studies and used as a powerful predictive tool. Currently pedogeography does not have a similar theoretical construct. Although island biodiversity and biological assemblages have been topics of widespread interest in biogeography, ecology and conservation biology, soil scientists have conducted few studies of pedodiversity and pedological assemblages in archipelagos. Several studies have demonstrated that pedodiversity and biodiversity patterns have striking similarities in very disparate environments and at different scales, thus it is possible to test for a similar construct of island pedogeography. We analyze similarities and differences in the pedosphere for three archipelagos with different origins: (i) oceanic-intra-plate chains islands (Hawaiian Islands), (ii) oceanic-intra-plate cluster islands (Canary Islands), (iii) non-marine land-bridge islands with volcanism associated with plate boundary conditions (Aegean Islands) and (iv) as a comparison, islands in a nonplate boundary setting (the British Isles). In the Canary Islands, we also compiled selected biological, physiographical, geological and climatic data for further analysis of pedodiversity, climatic diversity, geodiversity and biodiversity. Our pedogeographic analysis of the three archipelagos indicates archipelagos of varying origins contain different soil assemblages with plate tectonics as the main driving force. The similarities between pedodiversity and biodiversity are more remarkable than the differences. We tested the hypothesis that soil taxa distributions on island chains can be modelled as a power function similar to the species-area relationship (SAR) proposed by McArthur and Wilson for archipelagos. The SAR functional relationship has been widely corroborated in other biodiversity studies. The same patterns were obtained for pedodiversity and biodiversity in the British Isles, and after that in the Aegean Archipelago. In

  18. Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

    Science.gov (United States)

    Ager, Thomas A.; Carrara, Paul E.; Smith, Jane L.; Anne, Victoria; Johnson, Joni

    2010-03-01

    An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ˜12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (˜12,900 cal yr BP) was pine woodland ( Pinus contorta) with alder ( Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ˜12,240 cal yr BP, Sitka spruce ( Picea sitchensis) began to colonize the island while pine woodland declined. By ˜11,200 cal yr BP, mountain hemlock ( Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ˜10,180 cal yr BP, when western hemlock ( Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ˜7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars ( Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

  19. Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

    Science.gov (United States)

    Ager, T.A.; Carrara, P.E.; Smith, Jody L.; Anne, V.; Johnson, J.

    2010-01-01

    An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ???12,900??cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400??cal yr BP. The earliest known vegetation to develop on the island (???12,900??cal yr BP) was pine woodland (Pinus contorta) with alder (Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ???12,240??cal yr BP, Sitka spruce (Picea sitchensis) began to colonize the island while pine woodland declined. By ???11,200??cal yr BP, mountain hemlock (Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ???10,180??cal yr BP, when western hemlock (Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ???7100??cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars (Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

  20. Reef Island Evolution and Dynamics: Insights from the Indian and Pacific Oceans and Perspectives for the Spermonde Archipelago

    Directory of Open Access Journals (Sweden)

    Paul S. Kench

    2017-05-01

    Full Text Available Along southwestern Sulawesi, Indonesia, the Spermonde Archipelago comprises some 120 islands of variable size and degree of anthropogenic modification. Comparable to adjacent areas in Southeast Asia, the Spermonde Archipelago is characterized by the congregation of a naturally high marine biodiversity and, at the same time, a high population density influencing the surrounding environmental conditions. As a consequence, during the last decades, research projects that have been carried out in the Spermonde mainly focused on social, ecological, political and economic interactions. However, geological and geomorphological aspects of the coral reef islands are less well understood and there have been few studies undertaken since the pioneering work of Umbgrove, Kuenen, and Verstappen in the Indonesian archipelago in the early to mid-twentieth century. Here we review the existing studies, with a focus on the Spermonde Archipelago, and reconcile them with more recent works on reef island evolution and dynamics from the Indian and Pacific Oceans. This synthesis shows that reef islands in the Spermonde Archipelago are well suited for geomorphological investigations, and provides perspectives for future reef island research in that area that will have global interest. We identify four research priorities: (1 To identify the timing and chronology of island formation; (2 Improved understanding of carbonate budgets and sediment generation that contribute to island building; (3 Document morphological changes in reef islands at seasonal to decadal timescales, and; (4 Quantify the process regime that drives sediment transport and island change with particular focus on the role of different monsoon seasons.

  1. Tracing socio-economic impact of ferry provision in Zadar island archipelago

    Directory of Open Access Journals (Sweden)

    Zrinka Mendas

    2015-06-01

    Full Text Available This paper explores a socio-economic impact of ferry provision in Zadar island archipelago in Croatia. Poor frequency, accessibility, and unaffordable ferry prices to smaller islands have had a detrimental impact on island communities’ sustainability. This prompts for asking what constitutes the socio-economic impact of ferry provision on remote and rural islands’ sustainability. The paper analyses on one hand, regional traces of demographics of population, migration, employment and education; and on the other local traces of emerging island communities’ activities. Adverse impact from the financial resource scarcity and centralisation remain unavoidable, e.g., litoralisation, social exclusion, lack of trade inflows and outflows, entrepreneurship, and lack of employment opportunities for young generations. Island communities are aware of the need for alternative sustainable ways of managing their local economies and this study captures this through communal entrepreneurial and cultural activities. Political actors also must align with their needs in order to provide a long-term sustainable but limited support. Heterogeneity of space and data provides an opportunity for adopting pluralistic and interpretivistic insight and align more closely academic research with evidence-based policy related to rural planning for island archipelagos.

  2. Patterns of diversification in islands: A comparative study across three gecko genera in the Socotra Archipelago.

    Science.gov (United States)

    Garcia-Porta, Joan; Morales, Hernán E; Gómez-Díaz, Elena; Sindaco, Roberto; Carranza, Salvador

    2016-05-01

    In this study we used the complete fauna of geckos of the Socotra Archipelago to test whether the three gecko genera co-occurring in the islands (Pristurus, Hemidactylus and Haemodracon) produced similar outcomes of morphological and climatic diversification. To test this, we produced a time-calibrated tree of 346 geckos including all 16 endemic species of the archipelago and 26 potential close-relatives in the continent. Our dating estimates revealed that most of the diversity of geckos in the archipelago was the consequence of in situ diversification. However not all genera shared similar patterns of diversification. While in Hemidactylus and Haemodracon this involved great differences in body size and low levels of climatic diversification (mostly involving sympatric distributions), an opposite pattern appeared in Pristurus in which most of the diversification involved shifts in climatic envelopes (mostly involving allopatric and parapatric distributions) but almost no size differentiation. Consistently with this, Pristurus was the only genus in which rates of size diversification in islands were substantially lower than in the continent. This illustrates how different groups can greatly differ in their patterns of intra-island diversification and highlights the importance of taxon-dependent factors at determining different patterns of diversification in the same insular context.

  3. Oceanic archipelagos

    DEFF Research Database (Denmark)

    Triantis, Kostas A.; Whittaker, Robert James; Fernández-Palacios, José María

    2016-01-01

    Since the contributions of Charles Darwin and Alfred Russel Wallace, oceanic archipelagos have played a central role in the development of biogeography. However, despite the critical influence of oceanic islands on ecological and evolutionary theory, our focus has remained limited to either...... the island-level of specific archipelagos or single archipelagos. Recently, it was proposed that oceanic archipelagos qualify as biotic provinces, with diversity primarily reflecting a balance between speciation and extinction, with colonization having a minor role. Here we focus on major attributes...... of the archipelagic geological dynamics that can affect diversity at both the island and the archipelagic level. We also reaffirm that oceanic archipelagos are appropriate spatiotemporal units to frame analyses in order to understand large scale patterns of biodiversity....

  4. Genetic affinities between the Yami tribe people of Orchid Island and the Philippine Islanders of the Batanes archipelago.

    Science.gov (United States)

    Loo, Jun-Hun; Trejaut, Jean A; Yen, Ju-Chen; Chen, Zong-Sian; Lee, Chien-Liang; Lin, Marie

    2011-01-31

    Yami and Ivatan islanders are Austronesian speakers from Orchid Island and the Batanes archipelago that are located between Taiwan and the Philippines. The paternal genealogies of the Yami tribe from 1962 monograph of Wei and Liu were compared with our dataset of non-recombining Y (NRY) chromosomes from the corresponding families. Then mitochondrial DNA polymorphism was also analyzed to determine the matrilineal relationships between Yami, Ivatan, and other East Asian populations. The family relationships inferred from the NRY Phylogeny suggested a low number of paternal founders and agreed with the genealogy of Wei and Liu (P DNA variation in our data set ranged between 100-3,000 YBP.

  5. "IlVulcanoInforma": The restyling of the INGV Volcanological Information Centres, Aeolian Islands, Italy

    Science.gov (United States)

    D'Addezio, G.; Carapezza, M. L.; Riposati, D.; Team, L.

    2008-12-01

    Vulcano and Stromboli are the most active volcanoes of the Aeolian Islands. Vulcano is quiescent since the eruption of 1888-90 but in the last decades it experienced several crises with huge increase of gas output and temperature of the crater fumaroles, and variations in the magmatic gas components. Stromboli is characterized by a permanent mild explosive activity, episodically interrupted by major explosions, lava effusions, or paroxystic explosive events (October 2001: a tourist killed; December 2002: lava effusion, tsunami generated by flank collapse; April 2003: explosive paroxysm, block fallout on Ginostra village; February-March 2007: lava effusion and paroxysm). These islands are renowned tourist sites for the marvelous sea and the fascination that the volcanoes evoke. In fact, during summer risk increases as there are 10,000-15,000 persons per island (only a few hundreds in winter). Starting from the 1990 the INGV and the Civil Protection established a Volcanological Information Centre on each island with the main goal to inform population and tourists on the risks related to each volcano. During the year the two centres are visited by 8000-10,000 visitors coming from different countries. Researchers and trained students are involved in the educational activity devoted to inform visitors on the scientific aspects of volcano monitoring and hazard assessment and to ensure that tourists, willing to climb the summit crater area, will behave properly. In 2008 the Vulcano exhibition has been totally restyled. The INGV Laboratorio Grafica e Immagini has created for the project a composite and innovative graphic study. This includes a series of products (logos, brochures, panels ecc) with the intent to create new effective information means. The logo creation has been the first step for all the communications: an image with strong impact on volcano information distributed in strategic zones of the village to stimulate interest in the INGV centre and its exhibition.

  6. Late Quaternary relative sea-level changes and vertical movements at Lipari (Aeolian Islands)

    Science.gov (United States)

    Calanchi, N.; Lucchi, F.; Pirazzoli, P. A.; Romagnoli, C.; Tranne, C. A.; Radtke, U.; Reyss, J. L.; Rossi, P. L.

    2002-05-01

    Indicators of former sea-levels are recognised on the emergent portion of Lipari, Aeolian Islands. They correlate with three raised shorelines, located at elevations of 43-45 m above present sea-level (I), 23-27 m (II) and about 12 m (III). According to stratigraphical constraints, these shorelines correlate with the sea-level highstands corresponding to marine oxygen isotope substages 5e (124 ka), 5c (100 ka) and 5a (81 ka), respectively. The correlation of the shoreline I with substage 5e is supported by a U/Th age (119 +/- 6 ka) obtained from corals. Chronological and height data relevant to the fossil shorelines indicate that Lipari was affected by uplift with an average rate of 0.34 mm yr-1 during the past 125 ka. This uplift rate accords with the average uplift rates obtained, during the same time period, from the nearby islands of Filicudi (0.31 mm yr-1) and Salina (0.36 mm yr-1). Combined, these data suggest a similar uplift trend related to regional tectonic processes.In contrast to the long-term uplift, a localised submergence trend, documented especially for the last century, affects the eastern coast of Lipari. This subsidence is related to neo- and/or volcano-tectonic processes.

  7. Tephro- and chemo-stratigraphy of the Vulcanello Peninsula (Vulcano, Aeolian Islands)

    Science.gov (United States)

    Rosi, M.; Fusillo, R.; di Traglia, F.; Pistolesi, M.; Todman, A.; Menzies, M. A.

    2009-12-01

    New stratigraphic studies of the Vulcanello Peninsula have been used to better define the small-scale evolution of this young (1000 AD and 325±100 BP) volcanic center and to re-investigate the last 1000 years of volcanic history for the Island of Vulcano (Aeolian Islands, Southern Italy). Vulcanello Peninsula is the northern-most part of the Island of Vulcano. It comprises a shoshonitic lava platform and a volcanic edifice made up of three overlying cones, which are shoshonitic to trachytic in composition. Volcanic activity in this area was coeval with the recent eruptions of the La Fossa Cone, the present-day active center of the island. Our goal is to constrain the recent volcanic development of this mafic volcano and to focus on the historic eruptive activity of the two other recent or active centres in the southern Aeolian Islands, Mt. Pilato (Island of Lipari) and La Fossa Cone. In order to do so, we reconstructed the stratigraphical setting of the proximal deposits of the three Vulcanello cones, through the investigation of 25 outcrops. We analyzed the stratigraphy of the tephra blankets deposited on the lava platform, studying 10 trenches. Our intention is to integrate morphological, textural and chemical data in order to correlate these deposits with the Vulcanello, La Fossa Cone or Mt Pilato. LA-MC-ICPMS (RHUL) analysis of juvenile clasts is underway in order to investigate the evolution of the Vulcanello juvenile clasts. In addition 14C dating is planned on selected organic matter from the volcanostratigraphic sections. Our preliminary data for the Vulcanello proximal deposits suggest that each of the three cones experienced several eruptions, with a wide spectrum of eruptive styles and a diversity of chemistry. The oldest cone (Vulcanello I) is characterised by four different eruptions separated by minor unconformities or reworking material indicative of little or not time breaks in the eruptive cycle. The eruptions shift from Violent Strombolian to

  8. Magnetic fabric and remanent magnetization of pyroclastic surge deposits from Vulcano (Aeolian Islands, Italy)

    Science.gov (United States)

    Zanella, E.; De Astis, G.; Dellino, P.; Lanza, R.; La Volpe, L.

    1999-11-01

    Tufi di Grotte dei Rossi Inferiori are unwelded, fine-grained pyroclastic deposits of hydromagmatic origin emplaced between 21 and 11-8.6 ka at Vulcano (Aeolian Islands, Italy) by deposition through surges spreading laterally from inside the La Fossa caldera. In this study, the deposit's magnetic properties were investigated and interpreted in terms of eruptive and emplacement dynamics. Rock-magnetism data were supplemented by grain size and textural characteristic analyses as well as scanning electron microscope (SEM) investigations. Curie point measurements, isothermal remanent magnetization and microprobe analyses showed that magnetization is carried by low-Ti titanomagnetite. The size of the grains ranges from about 20 to 300 micrometres, their shape from equidimensional to highly elongated. The magnetic fabric is typical of fine-grained pyroclastics. Foliation is well developed and in most sites lineation is directed towards the source area of the La Fossa caldera. The remanent magnetization consists of two components whose blocking temperature spectra partially overlap. The direction of the low-temperature component is close to that of the axial dipole, and consistent with the palaeosecular variation curve for the Aeolian Islands. The high-temperature component is systematically shallowed and close to the direction of the magnetic lineation. The overall results suggest that the high-temperature component was acquired before, and the low-temperature component after, the actual deposition of grains. Immediately after eruption, the grains cooled and moved as free particles in the turbulent cloud during the expansion of the surge flows. Those particles with high blocking temperatures acquired a thermal remanence. They were then deposited and shear at the very base of the flow oriented them and imprinted the rock's fabric and high-temperature magnetization component. Volcanological and magnetic data suggest turbulent transportation and traction deposition of

  9. Coral reef destruction of Small island in 44 years and destructive fishing in Spermonde Archipelago, Indonesia

    Science.gov (United States)

    Nurdin, Nurjannah; Komatsu, Teruhisa; Rani, Chair; Supriadi; Fakhriyyah, Sitti; Agus

    2016-11-01

    Coral reefs are among the most diverse and threatened ecosystems on the planet. The most commonly stated for developing coral reef remote sensing techniques is to asses and or to monitor the status of these ecosystems. The study site was selected one of small island in inner zone Spermonde archipelago, Indonesia. We used Landsat MSS, Landsat TM, Landsat ETM, and Landsat OLI data to examine changes in the coral reefs of inner zone island in the Spermonde Archipelago from 1972 to 2016. The image processing are gap fills, atmospheric correction, geometric corrections, image composites, water column corrections, unsupervised classifications, and reclassification. Some of component change detection procedure was applied to define change. The results showed significant changes in 44 years. Disturbed coral reefs are typically characterized by loss of coral cover by increase in the abundance of dead corals and rubble. Local factors such as destructive fishing is direct destruction of inner zone island. While the impact of local threats may be reduced through management action, global threats to coral reefs are likely to increase in severity in the coming years.

  10. Eruptive history of western and central Aeolian Islands volcanoes (South Tyrrhenian Sea, Italy): temporal evolution of magmatism and of morphological structures

    Science.gov (United States)

    Leocat, E.; Gillot, P.; Peccerillo, A.

    2010-12-01

    The Aeolian Island archipelago is a complex volcanic province located on the continental margin of the Calabro-Peloritan basement. It emplaced in a geodynamic setting linked to the convergence of African and European plates. In this study, we focused on the western and central volcanoes that are respectively Alicudi-Filicudi-Salina and Lipari-Vulcano. They erupted the whole range of magmas typical of convergence settings : from calc-alkaline (CA) to potassic series (KS) through high-K CA (HKCA) and shoshonitic series (SHO). All these magma products were emitted in a span time of less than 300 ka that attests to the complexity of the volcano-tectonic evolution of this province. We report new geochronological data, based on the K/Ar Cassignol-Gillot technique, which is well suited for dating Quaternary volcanic materials. New geochemical analyses were realized on the dated samples in order to study the temporal evolution of the magmatism. These data sets were coupled with geomorphological analysis to study the relation between main morphological structures and eruptive styles. Before 180 ka, only the Filicudi, Salina and Lipari volcanoes had emerged activity. Their magmas have relatively the same CA composition, whereas some Lipari lavas have early HKCA affinity. Around 120-130 ka, Alicudi and Vulcano emerged simultaneously at the extremities of the archipelago. Alicudi products are less various and have the more primitive composition. SHO and HKCA products were emitted on Lipari and Vulcano, while only CA magmas were emplaced on Filicudi and Salina. After 40 ka, the last activity of Filicudi is characterized by mafic magmas of HKCA affinity. To the other extremity, similar products of SHO affinity were emplaced in southern Lipari and northern Vulcano. At this period, explosive activity with dacitic pumices occurred in Salina. The degree of differentiation and the K enrichment increase from western sector to central sector volcanoes and through time except at

  11. Testing the island effect on phenotypic diversification: insights from the Hemidactylus geckos of the Socotra Archipelago.

    Science.gov (United States)

    Garcia-Porta, Joan; Šmíd, Jiří; Sol, Daniel; Fasola, Mauro; Carranza, Salvador

    2016-04-13

    Island colonization is often assumed to trigger extreme levels of phenotypic diversification. Yet, empirical evidence suggests that it does not always so. In this study we test this hypothesis using a completely sampled mainland-island system, the arid clade of Hemidactylus, a group of geckos mainly distributed across Africa, Arabia and the Socotra Archipelago. To such purpose, we generated a new molecular phylogeny of the group on which we mapped body size and head proportions. We then explored whether island and continental taxa shared the same morphospace and differed in their disparities and tempos of evolution. Insular species produced the most extreme sizes of the radiation, involving accelerated rates of evolution and higher disparities compared with most (but not all) of the continental groups. In contrast, head proportions exhibited constant evolutionary rates across the radiation and similar disparities in islands compared with the continent. These results, although generally consistent with the notion that islands promote high morphological disparity, reveal at the same time a complex scenario in which different traits may experience different evolutionary patterns in the same mainland-island system and continental groups do not always present low levels of morphological diversification compared to insular groups.

  12. First occurrence of close-to-ideal Kirkiite at Vulcano (Aeolian Islands, Italy)

    DEFF Research Database (Denmark)

    Pinto, Daniela; Balic-Zunic, Tonci; Garavelli, anna;

    2006-01-01

    Samples of kirkiite from the high temperature fumaroles of La Fossa crater of Vulcano (Aeolian islands, Italy) were chemically and structurally investigated in this work. Associated minerals are vurroite, bismuthinite, galenobismutite, cannizzarite, lillianite, heyrovsk ite, galena, and other less...... characterized Pb(Bi)-sulfochlorides. Electron-microprobe analyses gave the average chemical formula Pb10.00Bi3.01As3.01(S18.47Se0.44C10.06) which is very close to the ideal composition of kirkiite, Pb10Bi3As3S19, and indeed significantly closer than the composition of the type specimen, Pb10.08Bi2.55Sb0.13As2...... in more regular and symmetric coordination polyhedra than in the holotype, as well as in the overall regularity of the structure. The increased Bi:As ratio produces an elongation of the a and b lattice periods, and a shortening of the c period, and increases the frequency of twinning in kirkiite....

  13. Halocarbons and other trace heteroatomic organic compounds in volcanic gases from Vulcano (Aeolian Islands, Italy)

    Science.gov (United States)

    Schwandner, Florian M.; Seward, Terry M.; Giże, Andrew P.; Hall, Keith; Dietrich, Volker J.

    2013-01-01

    Adsorbent-trapped volcanic gases, sublimates and condensates from active vents of the La Fossa crater on the island of Vulcano (Aeolian Islands, Italy) as well as ambient and industrial air were quantitatively analyzed by Short-Path Thermal Desorption-Solid Phase Microextraction-Cryotrapping-Gas Chromatography/Mass Spectrometry (SPTD-SPME-CF-GC-MS). Among the over 200 detected and quantified compounds are alkanes, alkenes, arenes, phenols, aldehydes, carboxylic acids, esters, ketones, nitriles, PAHs and their halogenated, methylated and sulfonated derivatives, as well as various heterocyclic compounds including thiophenes and furans. Most compounds are found at concentrations well above laboratory, ambient air, adsorbent and field blank levels. For some analytes (e.g., CFC-11, CH2Cl2, CH3Br), concentrations are up to several orders of magnitude greater than even mid-latitudinal industrial urban air maxima. Air or laboratory contamination is negligible or absent on the basis of noble gas measurements and their isotopic ratios. The organic compounds are interpreted as the product of abiogenic gas-phase radical reactions. On the basis of isomer abundances, n-alkane distributions and substitution patterns the compounds are thought to have formed by high-temperature (e.g., 900 °C) alkyl free radical reactions and halide electrophilic substitution on arenes, alkanes and alkenes. The apparent abiogenic organic chemistry of volcanic gases may give insights into metal transport processes during the formation and alteration of hydrothermal ore deposits, into the natural volcanic source strength of ozone-depleting atmospheric trace gases (i.e., halocarbons), into possibly sensitive trace gas redox pairs as potential early indicators of subsurface changes on volcanoes in the state of imminent unrest, and into the possible hydrothermal origin of early life on Earth, as indicated by the presence of simple amino acids, nitriles, and alkanoic acids.

  14. Models of oceanic island biogeography: changing perspectives on biodiversity dynamics in archipelagoes

    Directory of Open Access Journals (Sweden)

    Lawrence R Heaney

    2013-12-01

    Full Text Available Models of biogeographic processes can both enhance and inhibit our ability to ask questions that guide our understanding of patterns and processes. The two ‘traditional’ models of island biogeography, the Equilibrium Model and the Vicariance Model, raise important and insightful questions about relevant processes, but both fail to raise many crucial questions. An example involving the non-volant mammals of the Philippine archipelago shows that both models highlight some, but not all, relevant patterns and processes. The more recently proposed General Dynamic Model successfully combines many of the positive aspects of the two traditional models, but leaves some important questions unasked. We pose a number of questions here that may help guide further development of models of island biogeography.

  15. Integrating paleoecology and genetics of bird populations in two sky island archipelagos

    Directory of Open Access Journals (Sweden)

    Bowen Bonnie S

    2008-06-01

    Full Text Available Abstract Background Genetic tests of paleoecological hypotheses have been rare, partly because recent genetic divergence is difficult to detect and time. According to fossil plant data, continuous woodland in the southwestern USA and northern Mexico became fragmented during the last 10,000 years, as warming caused cool-adapted species to retreat to high elevations. Most genetic studies of resulting 'sky islands' have either failed to detect recent divergence or have found discordant evidence for ancient divergence. We test this paleoecological hypothesis for the region with intraspecific mitochondrial DNA and microsatellite data from sky-island populations of a sedentary bird, the Mexican jay (Aphelocoma ultramarina. We predicted that populations on different sky islands would share common, ancestral alleles that existed during the last glaciation, but that populations on each sky island, owing to their isolation, would contain unique variants of postglacial origin. We also predicted that divergence times estimated from corrected genetic distance and a coalescence model would post-date the last glacial maximum. Results Our results provide multiple independent lines of support for postglacial divergence, with the predicted pattern of shared and unique mitochondrial DNA haplotypes appearing in two independent sky-island archipelagos, and most estimates of divergence time based on corrected genetic distance post-dating the last glacial maximum. Likewise, an isolation model based on multilocus gene coalescence indicated postglacial divergence of five pairs of sky islands. In contrast to their similar recent histories, the two archipelagos had dissimilar historical patterns in that sky islands in Arizona showed evidence for older divergence, suggesting different responses to the last glaciation. Conclusion This study is one of the first to provide explicit support from genetic data for a postglacial divergence scenario predicted by one of the best

  16. Competing Notions of Diversity in Archipelago Tourism: Transport Logistics, Official Rhetoric and Inter-Island Rivalry in the Azores

    Directory of Open Access Journals (Sweden)

    Eduardo Costa Duarte Ferreira

    2013-05-01

    Full Text Available Contending and competing geographies are often implicitly involved in archipelagic spaces. Various small island states and territories with multi-island geographies have flourishing tourism industries that presuppose an archipelagic experience: visitors are encouraged to explore and sample different island constituents of the territory. This strategy taps into different tourism niche markets, improves local value added, and shares tourism revenue beyond key nodes and urban centers. The organization of such an important economic activity however often reflects a ‘one-size-fits-all’, tightly coordinated, frequently contrived process that does not necessarily speak to the cultural and biogeographical forms of diversity that reside in the archipelago. This paper offers the notion of archipelago as a new way of rethinking problems and challenges encountered in island tourism, and then assesses the implications of this conceptualization on the representation of ‘the archipelago’ in the Azores, Portugal, and reviews what this approach means and implies for sustainable tourism policy.

  17. Genetic affinities between the Yami tribe people of Orchid Island and the Philippine Islanders of the Batanes archipelago

    Directory of Open Access Journals (Sweden)

    Lee Chien-Liang

    2011-01-01

    Full Text Available Abstract Background Yami and Ivatan islanders are Austronesian speakers from Orchid Island and the Batanes archipelago that are located between Taiwan and the Philippines. The paternal genealogies of the Yami tribe from 1962 monograph of Wei and Liu were compared with our dataset of non-recombining Y (NRY chromosomes from the corresponding families. Then mitochondrial DNA polymorphism was also analyzed to determine the matrilineal relationships between Yami, Ivatan, and other East Asian populations. Results The family relationships inferred from the NRY Phylogeny suggested a low number of paternal founders and agreed with the genealogy of Wei and Liu (P The genetic affinity seen between Yami and Taiwanese aborigines or between Ivatan and the Philippine people was closer than that between Yami and Ivatan, suggesting that the Orchid islanders were colonized separately by their nearest neighbors and bred in isolation. However a northward gene flow to Orchid Island from the Philippines was suspected as Yami and Ivatan peoples both speak Western Malayo-Polynesian languages which are not spoken in Taiwan. Actually, only very little gene flow was observed between Yami and Ivatan or between Yami and the Philippines as indicated by the sharing of mtDNA haplogroup B4a1a4 and one O1a1* Y-STR lineage. Conclusions The NRY and mtDNA genetic information among Yami tribe peoples fitted well the patrilocal society model proposed by Wei and Liu. In this proposal, there were likely few genetic exchanges among Yami and the Philippine people. Trading activities may have contributed to the diffusion of Malayo-Polynesian languages among them. Finally, artifacts dating 4,000 YBP, found on Orchid Island and indicating association with the Out of Taiwan hypothesis might be related to a pioneering stage of settlement, as most dating estimates inferred from DNA variation in our data set ranged between 100-3,000 YBP.

  18. Archipelago-wide island restoration in the Galápagos Islands: reducing costs of invasive mammal eradication programs and reinvasion risk.

    Science.gov (United States)

    Carrion, Victor; Donlan, C Josh; Campbell, Karl J; Lavoie, Christian; Cruz, Felipe

    2011-05-11

    Invasive alien mammals are the major driver of biodiversity loss and ecosystem degradation on islands. Over the past three decades, invasive mammal eradication from islands has become one of society's most powerful tools for preventing extinction of insular endemics and restoring insular ecosystems. As practitioners tackle larger islands for restoration, three factors will heavily influence success and outcomes: the degree of local support, the ability to mitigate for non-target impacts, and the ability to eradicate non-native species more cost-effectively. Investments in removing invasive species, however, must be weighed against the risk of reintroduction. One way to reduce reintroduction risks is to eradicate the target invasive species from an entire archipelago, and thus eliminate readily available sources. We illustrate the costs and benefits of this approach with the efforts to remove invasive goats from the Galápagos Islands. Project Isabela, the world's largest island restoration effort to date, removed >140,000 goats from >500,000 ha for a cost of US$10.5 million. Leveraging the capacity built during Project Isabela, and given that goat reintroductions have been common over the past decade, we implemented an archipelago-wide goat eradication strategy. Feral goats remain on three islands in the archipelago, and removal efforts are underway. Efforts on the Galápagos Islands demonstrate that for some species, island size is no longer the limiting factor with respect to eradication. Rather, bureaucratic processes, financing, political will, and stakeholder approval appear to be the new challenges. Eradication efforts have delivered a suite of biodiversity benefits that are in the process of revealing themselves. The costs of rectifying intentional reintroductions are high in terms of financial and human resources. Reducing the archipelago-wide goat density to low levels is a technical approach to reducing reintroduction risk in the short-term, and is being

  19. New insights into the Aeolian Islands and other arc source compositions from high-precision olivine chemistry

    Science.gov (United States)

    Zamboni, Denis; Trela, Jarek; Gazel, Esteban; Sobolev, Alexander V.; Cannatelli, Claudia; Lucchi, Federico; Batanova, Valentina G.; De Vivo, Benedetto

    2017-02-01

    The Aeolian arc (Italy) is characterized by some of the strongest along-the-arc geochemical variations in the planet, making it an ideal location to study the effect of subducting components in modifying the mantle source of island arc melts. Here, we use high-precision element concentrations in primitive phenocrystic olivine from basalts along the arc to elucidate the effects of mantle source modification by the subduction process. Olivines from this arc have Ni concentrations and Fe/Mn ratios that show similarity to peridotite sources that melted to produce mid-ocean ridge basalts. Nevertheless, they also have systematically lower Ca concentrations and Fe/Mn ratios that broadly overlap with olivines from the available global arc array. These phenocrysts also do not show significant variations in Ca as a function of olivine forsterite content. The global data suggest that all olivines crystallizing from island-arc melts have suppressed Ca concentrations and Fe/Mn ratios, relative to olivines derived from melts at intraplate and mid-ocean ridge settings suggesting elevated H2O concentrations and higher oxidation state of the equilibrium melts. Based on olivine chemistry, we interpret a predominantly peridotite source (fluxed by subduction fluids) beneath the Aeolian Arc and also for other examples of arc-related lavas.

  20. Epidemiological survey of zoonotic helminths in feral cats in Gran Canaria island (Macaronesian archipelago-Spain).

    Science.gov (United States)

    Rodríguez-Ponce, Eligia; González, Jorge F; Conde de Felipe, Magnolia; Hernández, Julia N; Raduan Jaber, J

    2016-09-01

    The presence of zoonotic parasites in feral cats have been widely considered all over the world. In Gran Canaria (Macaronesian archipelago, Canary Islands, Spain) the number of feral cats has grown out of control in urban and rural areas. 48 of Felis catus captured in different Gran Canaria areas were studied. Animals were necropsied and several organs were systematically examined in order to collect and identify macroscopic parasites. In addition, coprological tests were done in 28 cats. There were no statistically significant differences in the prevalence rate among sex, age or capture area, showing an overall prevalence of helminths of 77.1%. The most common tapeworms were Dipylidium caninum (64.6%) and Taenia taeniaeformis (31.3%), followed by the nematodes Toxocara cati (20.8%), Ancylostoma tubaeforme (18.8%), Aelurostrongylusabstrusus (10.4%) and Trichuris vulpis (2.08%). We also find several eggs of Alaria alata in the small intestine of one cat (2.08%), being the first description of this trematode in cats in the Canary Islands. Aproximatelly, 40% of the studied cats harboured more than one parasite. High rates of zoonotic species found in these animals suggest the need of controling parasitic infections and preventive measures against them.

  1. Volatile organic compounds (VOCs) in air from Nisyros Island (Dodecanese Archipelago, Greece): Natural versus anthropogenic sources.

    Science.gov (United States)

    Tassi, F; Capecchiacci, F; Giannini, L; Vougioukalakis, G E; Vaselli, O

    2013-09-01

    This study presents the chemical composition of VOCs in air and gas discharges collected at Nisyros Island (Dodecanese Archipelago, Greece). The main goals are i) to discriminate between natural and anthropogenic VOC sources and ii) to evaluate their impact on local air quality. Up to 63 different VOCs were recognized and quantitatively determined in 6 fumaroles and 19 air samples collected in the Lakki caldera, where fumarolic emissions are located, and the outer ring of the island, including the Mandraki village and the main harbor. Air samples from the crater area show significant concentrations of alkanes, alkenes, cyclic, aromatics, and S- and O-bearing heterocycles directly deriving from the hydrothermal system, as well as secondary O-bearing compounds from oxidation of primary VOCs. At Mandraki village, C6H6/Σ(methylated aromatics) and Σ(linear)/Σ(branched) alkanes ratios <1 allow to distinguish an anthropogenic source related to emissions from outlet pipes of touristic and private boats and buses.

  2. The origins of ambient biological sound from coral reef ecosystems in the Line Islands archipelago.

    Science.gov (United States)

    Freeman, Simon E; Rohwer, Forest L; D'Spain, Gerald L; Friedlander, Alan M; Gregg, Allison K; Sandin, Stuart A; Buckingham, Michael J

    2014-04-01

    Although ambient biological underwater sound was first characterized more than 60 years ago, attributing specific components of ambient sound to their creators remains a challenge. Noise produced by snapping shrimp typically dominates the ambient spectra near tropical coasts, but significant unexplained spectral variation exists. Here, evidence is presented indicating that a discernible contribution to the ambient sound field over coral reef ecosystems in the Line Islands archipelago originates from the interaction of hard-shelled benthic macro-organisms with the coral substrate. Recordings show a broad spectral peak centered between 14.30 and 14.63 kHz, incoherently added to a noise floor typically associated with relatively "white" snapping shrimp sounds. A 4.6 to 6.2 dB increase of pressure spectral density level in the 11 to 17 kHz band occurs simultaneously with an increase in benthic invertebrate activity at night, quantified through time-lapse underwater photography. Spectral-level-filtered recordings of hermit crabs Clibanarius diugeti in quiet aquarium conditions reveal that transient sounds produced by the interaction between the crustaceans' carapace, shell, and coral substrate are spectrally consistent with Line Islands recordings. Coral reef ecosystems are highly interconnected and subtle yet important ecological changes may be detected quantitatively through passive monitoring that utilizes the acoustic byproducts of biological activity.

  3. Oceanic archipelagos

    DEFF Research Database (Denmark)

    Triantis, Kostas A.; Whittaker, Robert James; Fernández-Palacios, José María;

    2016-01-01

    Since the contributions of Charles Darwin and Alfred Russel Wallace, oceanic archipelagos have played a central role in the development of biogeography. However, despite the critical influence of oceanic islands on ecological and evolutionary theory, our focus has remained limited to either the i...

  4. Deep water gravity core from the Marsili Basin (Tyrrhenian Sea) records Pleistocenic Holocenic explosive events and instability of the Aeolian Archipelago, (Italy)

    Science.gov (United States)

    Di Roberto, A.; Rosi, M.; Bertagnini, A.; Marani, M. P.; Gamberi, F.; Del Principe, A.

    2008-10-01

    A 4.8 m long gravity core was recovered on a relative topographic high in the northern part of the Marsili Basin (southern Tyrrhenian Sea) at a water depth of 3200 m. The core was taken in order to decipher the sedimentary record of the past volcanic events of the nearby Aeolian arc. A succession of thin (2 cm to 5 cm thick) fine-grained turbidites, mainly of volcaniclastic origin, topped by hemipelagic mud layers and a number of primary tephra layers were recovered by the core. The most prominent turbidite occurs in the lower part of the core at 385 cm. It consists of a 20 cm-thick, thinning-upward, pebble to sand-sized bed. Grain-size analysis and component compositions in the 0.063-0.250 mm size fractions were determined on thirty samples taken from primary tephra beds and the silty-sandy basal part of the volcaniclastic turbidite units. SEM scans and glass fraction chemical analyses were successively carried out on a selection of 17 samples. To aid source correlation and comparison, sub-aerial tephras of the Lower Pollara (Salina, 24 ± 3.6 ka), Gabellotto-Fiumebianco (Lipari, 8.5 or 11.5 ka), Monte Pilato (Lipari, 749 or 580 AD) and Secche di Lazzaro (Stromboli, ~ 5 ka) eruptions were also analyzed with the same procedure. Primary tephra respectively belonging to the eruptions of Lower Pollara, Gabellotto-Fiumebianco and Vesuvius (AP eruptions 3.5 ka-79 AD) were identified in the core at the expected relative stratigraphic depths. Two turbidite beds composed of monogenic glass shards were also identified and interpreted as the remobilisation of primary tephras of Secche di Lazzaro (Stromboli, 5 ka) and Pilato (Lipari, 580 or 749 AD). Tephrochronology results indicate that the cored sequence formed in the last 30 ka suggesting an average sedimentation rate of 0.15-0.17 mm/y. The thick pebbly sandy turbidite unit in the lower part of the core has component and glass composition compatible with the Lower Pollara volcanic sequence of Salina Island. In view of the

  5. Impact factors identification of spatial heterogeneity of herbaceous plant diversity on five southern islands of Miaodao Archipelago in North China

    Science.gov (United States)

    Chi, Yuan; Shi, Honghua; Wang, Xiaoli; Qin, Xuebo; Zheng, Wei; Peng, Shitao

    2016-09-01

    Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity. Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patterns. Five southern islands in the Miaodao Archipelago, North China were studied herein. The spatial distribution of herbaceous plant diversity on these islands was analyzed, and the impact factors and their degree of impact on spatial heterogeneity were identified using CCA ordination and ANOVA. The results reveal 114 herbaceous plant species, belonging to 94 genera from 34 families in the 50 plots sampled. The total species numbers on different islands were significantly positively correlated with island area, and the average α diversity was correlated with human activities, while the β diversity among islands was more affected by island area than mutual distances. Spatial heterogeneity within islands indicated that the diversities were generally high in areas with higher altitude, slope, total nitrogen, total carbon, and canopy density, and lower moisture content, pH, total phosphorus, total potassium, and aspect. Among the environmental factors, pH, canopy density, total K, total P, moisture content, altitude, and slope had significant gross effects, but only canopy density exhibited a significant net effect. Terrain affected diversity by restricting plantation, plantation in turn influenced soil properties and the two together affected diversity. Therefore, plantation was ultimately the fundamental driving factor for spatial heterogeneity in herbaceous plant diversity on the five islands.

  6. Assessment of island beach erosion due to sea level rise: the case of the Aegean archipelago (Eastern Mediterranean)

    Science.gov (United States)

    Monioudi, Isavela N.; Velegrakis, Adonis F.; Chatzipavlis, Antonis E.; Rigos, Anastasios; Karambas, Theophanis; Vousdoukas, Michalis I.; Hasiotis, Thomas; Koukourouvli, Nikoletta; Peduzzi, Pascal; Manoutsoglou, Eva; Poulos, Serafim E.; Collins, Michael B.

    2017-03-01

    The present contribution constitutes the first comprehensive attempt to (a) record the spatial characteristics of the beaches of the Aegean archipelago (Greece), a critical resource for both the local and national economy, and (b) provide a rapid assessment of the impacts of the long-term and episodic sea level rise (SLR) under different scenarios. Spatial information and other attributes (e.g., presence of coastal protection works and backshore development) of the beaches of the 58 largest islands of the archipelago were obtained on the basis of remote-sensed images available on the web. Ranges of SLR-induced beach retreats under different morphological, sedimentological and hydrodynamic forcing, and SLR scenarios were estimated using suitable ensembles of cross-shore (1-D) morphodynamic models. These ranges, combined with empirically derived estimations of wave run-up induced flooding, were then compared with the recorded maximum beach widths to provide ranges of retreat/erosion and flooding at the archipelago scale. The spatial information shows that the Aegean pocket beaches may be particularly vulnerable to mean sea level rise (MSLR) and episodic SLRs due to (i) their narrow widths (about 59 % of the beaches have maximum widths economic resource of the Aegean archipelago.

  7. Ciguatera fish poisoning: Incidence, health costs and risk perception on Moorea Island (Society archipelago, French Polynesia).

    Science.gov (United States)

    Morin, Ewen; Gatti, Clémence; Bambridge, Tamatoa; Chinain, Mireille

    2016-12-01

    Ciguatera Fish Poisoning (CFP) is a non-bacterial seafood poisoning well characterized in the remote archipelagos of French Polynesia, yet poorly documented in the Society archipelago, most notably on Moorea, the second most populated island in French Polynesia, which counts a high proportion of fishermen fishing on a regular basis. To address this knowledge gap, a holistic study of the ciguatera issue was conducted on Moorea. First, ciguatera risk was analysed in terms of incidence rate, fish species most commonly involved and risk stratification in Moorea lagoon based on 2007-2013 epidemiological data. A mean incidence rate of 8 cases per 10,000 inhabitants for the study period and an average under-reporting rate of 54% were found. Taking into account hospitalization and medication fees, and loss of productive days, the health-related costs due to CFP were estimated to be USD $1613 and $749 for each reported and unreported case, respectively, with an overall cost of USD $241,847 for the study period. Comparison of the present status of CFP on Moorea with a risk map established in the late 1970's showed that the spatial distribution of the risk has stayed relatively stable in time, with the north shore of the island remaining the most prone to ciguatera. Evaluation of the current knowledge on CFP among different populations groups, i.e. fishermen, residents and visitors, was also conducted through direct and indirect interviews. About half of the fishermen interviewed were actually able to identify risky fishing areas. While, overall, the CFP risk perception in the fishing community of Moorea seemed accurate, although not scientifically complete, it was sufficient for the safe practice of their fishing activities. This may be due in part to adaptive responses adopted by 36% of the fishermen interviewed, such as the avoidance of either high-risk fishing sites or toxic species. At the residents and visitors' level, the study points out a striking lack of awareness

  8. Petrology and geochemistry of volcanic rocks from the island of Panarea: implications for mantle evolution beneath the Aeolian island arc (southern Tyrrhenian sea)

    Science.gov (United States)

    Calanchi, N.; Peccerillo, A.; Tranne, C. A.; Lucchini, F.; Rossi, P. L.; Kempton, P.; Barbieri, M.; Wu, T. W.

    2002-06-01

    Major, trace element and radiogenic isotope (Sr, Nd, Pb) data are reported for a suite of rocks from the Panarea volcano, a large structure that is largely hidden below sea level and outcrops only as a group of small islands between Lipari-Vulcano and Stromboli in the eastern Aeolian arc. The exposed rocks mostly consist of high-potassium calc-alkaline (HKCA) andesites, dacites and some rhyolites; shoshonitic basalts have been collected from submarine centres; mafic calc-alkaline (CA) rocks occur as thin layers of late-erupted strombolian scoriae. Major and trace element data are scattered, but define generally linear trends on inter-element diagrams; Sr-isotope ratios do not display significant increase with evolution, although rough positive trends of 87Sr/ 86Sr versus SiO 2 and Rb/Sr can be recognised within some units. The mafic rocks display varying enrichment in potassium, from CA to shoshonitic compositions, and are characterised by variable abundances of incompatible trace elements, which increase with potassium. There is an increase of 87Sr/ 86Sr ratios and a decrease of 143Nd/ 144Nd and 206Pb/ 204Pb ratios from CA to HKCA and shoshonitic mafic rocks. The scattered and incomplete nature of the outcrops make it difficult to constrain magmatic evolution at Panarea; geochemical and isotopic data suggest that AFC and mixing were important evolutionary processes. However, geochemical modelling does not support the possibility that the first-order compositional variations observed in the mafic rocks are the result of these processes, and suggests a genesis in a heterogeneous mantle source. Recent studies have highlighted strong differences in terms of incompatible trace element ratios and isotopic signatures, between the western-central and the eastern Aeolian arc. Rocks from the western islands (Alicudi, Filicudi, Salina, Vulcano) have typical magmatic arc geochemical signatures and relatively unradiogenic Sr-isotope compositions. By contrast, the eastern

  9. An assessment of the record in compositional variations from mantle source to magmatism at East Island, Crozet archipelago

    Science.gov (United States)

    Meyzen, C. M.; Marzoli, A.; Bellieni, G.

    2013-12-01

    The Crozet archipelago, located midway between Madagascar and Antarctica, constitutes the emerged part of the easternmost bank of the Crozet plateau, which lies upon upper Cretaceous oceanic seafloor derived from the Southeast Indian Ridge. It forms an elongated chain of five islands and islets, divided into two groups: an older eastern island group (Terres Australes et Antarctiques Francaises' expedition in 1969 from the northern part of East Island. Our alkali basalts from the Crozet archipelago are distinct from other oceanic within-plate magmatic rocks in showing ubiquitous large depletions in LILE with respect to other incompatible elements, although these rocks constitute one of the most incompatible-element-enriched suites among Earth's oceanic island basalts (OIB). The similarity of their trace element ratios and parallelism of their rare earth element patterns indicate: (1) a mantle source homogeneity over at least 1 Ma; (2) an uniformity of the melting conditions (i.e. degree of melting and residual mineralogy) during most of the sub-aerial eruptive history involving very small melting degrees of a garnet-phlogopite bearing, enriched mantle source, as to be expected to occur beneath an old tectonic plate where the bottom of the lithosphere is likely near the garnet to spinel transition. We will present new geodynamical and geochemical constraints on the mechanisms of formation for such garnet-phlogopite-bearing sources in oceanic island environments.

  10. Mixing, Assimilation, Storage and Homogenization, Aeolian Islands, Italy: Evidence from In situ Plagioclase Data from Alicudi Island

    Science.gov (United States)

    Hunt, R.; Bohrson, W. A.; Mayfield, A. M.; Creamer, J. B.

    2011-12-01

    In situ plagioclase data can provide time-transgressive information about petrogenetic processes that contribute to compositional diversity, thereby improving our ability to predict eruption style and to manage associated hazards. Alicudi, Aeolian Island Arc, Italy has a compositional range separated into 3 eruptive stages: stage 1 basalts; stage 2 basaltic andesites; stage 3 andesites (Peccerillo et al., 2004). Plagioclase from 10 samples that span this compositional and temporal range have been analyzed to elucidate magma chamber processes at this arc volcano. Through Nomarski Differential Interference Contrast imaging, 4 textural types were defined for each sample: simple oscillatory; complex oscillatory; sieved/patchy intermediate zone; sieve/patchy core. Andesitic plagioclase commonly exhibits patchy/sieve textures, whereas basaltic plagioclase commonly shows simple or complex oscillatory textures. Locations of core to rim major element analyses are based on textural boundaries. Microprobe results reveal ranges of An50-An88 in basalts, An42-An93 in basaltic andesites, and An45-An88 in andesites. Stage 1 and 2 cores and rims have a wide range in An. Stage 3 cores also have a wide range in An, but are dominated by lower values. In most samples, increasing An content of ≥10% is noted rimward of dissolution rims or within sieved/patchy zones, consistent with possible recharge events. Results of Tukey's Test (analysis of variance) suggest plagioclase crystals are related for stages 1 and 2. Stage 3 cores are unrelated to stage 1 and 2 cores. Laser Ablation Sr isotope data confirm variable 87Sr/86Sr for distinct textural types, and where possible, core and rim 87Sr/86Sr. Basalt plagioclase has the highest and most variable 87Sr/86Sr (0.70327-0.70375), whereas andesite plagioclase has the lowest and least variable (0.70284-0.70353). Whole rock 87Sr/86Sr (0.70316-0.70392) are consistent with in situ 87Sr/86Sr. Collectively, the data suggest mixing, assimilation

  11. Islands beneath islands: phylogeography of a groundwater amphipod crustacean in the Balearic archipelago

    Directory of Open Access Journals (Sweden)

    Juan Carlos

    2011-07-01

    Full Text Available Abstract Background Metacrangonyctidae (Amphipoda, Crustacea is an enigmatic continental subterranean water family of marine origin (thalassoid. One of the species in the genus, Metacrangonyx longipes, is endemic to the Balearic islands of Mallorca and Menorca (W Mediterranean. It has been suggested that the origin and distribution of thalassoid crustaceans could be explained by one of two alternative hypotheses: (1 active colonization of inland freshwater aquifers by a marine ancestor, followed by an adaptative shift; or (2 passive colonization by stranding of ancestral marine populations in coastal aquifers during marine regressions. A comparison of phylogenies, phylogeographic patterns and age estimations of clades should discriminate in favour of one of these two proposals. Results Phylogenetic relationships within M. longipes based on three mitochondrial DNA (mtDNA and one nuclear marker revealed five genetically divergent and geographically structured clades. Analyses of cytochrome oxidase subunit 1 (cox1 mtDNA data showed the occurrence of a high geographic population subdivision in both islands, with current gene flow occurring exclusively between sites located in close proximity. Molecular-clock estimations dated the origin of M. longipes previous to about 6 Ma, whereas major cladogenetic events within the species took place between 4.2 and 2.0 Ma. Conclusions M. longipes displayed a surprisingly old and highly fragmented population structure, with major episodes of cladogenesis within the species roughly correlating with some of the major marine transgression-regression episodes that affected the region during the last 6 Ma. Eustatic changes (vicariant events -not active range expansion of marine littoral ancestors colonizing desalinated habitats-explain the phylogeographic pattern observed in M. longipes.

  12. New data on Upper Carboniferous–Lower Permian deposits of Bol'shevik Island, Severnaya Zemlya Archipelago

    Directory of Open Access Journals (Sweden)

    Victoria B. Ershova

    2015-05-01

    Full Text Available We present here a detailed study of the Upper Carboniferous–Lower Permian stratigraphy of Bol'shevik Island in the Severnaya Zemlya Archipelago, consisting of the analysis of sedimentary structures and lithostratigraphy, U/Pb detrital zircon dating and structural studies. The preserved sedimentary structures suggest that the studied strata were deposited in a relatively small meandering fluvial system. U/Pb dating of detrital zircons reveals that the Upper Carboniferous–Lower Permian sandstones contain a primary age population ranging from 450 to 570 millions of years, with a predominance of Early–Middle Ordovician zircons. This detrital zircon distribution indicates that the studied formations were derived locally from the erosion of Lower Ordovician deposits of Bol'shevik Island or elsewhere in the archipelago. Our structural studies suggest that Upper Carboniferous–Lower Permian deposits are deformed into a series of west–north-west verging open asymmetric folds, suggesting a west–north-west direction of tectonic transport and that deformation across the island is post-Early Permian in age.

  13. Recent cryptic extinction of squamate reptiles on Yoronjima Island of the Ryukyu Archipelago, Japan, inferred from garbage dump remains

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nakamura

    2013-07-01

    Full Text Available We report recent skeletal remains of squamate reptiles screened from an old garbage dump deposit found on Yoronjima Island, a small island of the Ryukyu Archipelago, in the subtropical northwestern Pacific. Identified remains include at least three species of terrestrial snakes, one sea snake, and seven species of lizards. Among these, the Ryukyu Short-legged Skink, Ateuchosaurus pellopleurus; Kuroiwa’s Leopard Gecko, Goniurosaurus kuroiwae; and one unidentified Gekko species constitute entirely new findings. For a further two snake species and one lizard species, the evidence presented here is the first specimen-based documentation that these species existed on this island, where they are now evidently absent. The present absence of these species on Yoronjima is mainly attributable to predation by the Japanese Weasel, Mustela itatsi, introduced in the mid-1950s. Our results demonstrate a prominent case of recent, sizable deterioration of insular herpetofaunal diversity, which has never been documented with certainty in the Ryukyu Archipelago, and suggest that human influence should be taken into account in biodiversity research in this area.

  14. The high resolution bathymetric map of the exhalative area of Panarea (Aeolian Islands, Italy

    Directory of Open Access Journals (Sweden)

    G. Bortoluzzi

    2005-06-01

    Full Text Available On November 3, 2002 a shallow submarine gas eruption occurred in an area of 2.3 km2 east of Panarea (Aeolian volcanic arc, Southern Thyrrenian Sea, Italy. The exhalative area, surrounded by the islets of Dattilo, Panarelli, Lisca Bianca, Bottaro and Lisca Nera, has been known since historical times for the hydrothermal activity related to the Panarea volcanic complex. Due to the exceptional characteristics of the phenomenon, different geological, geochemical, geophysical and studies were carried out in this still poorly known volcanic area. A particular effort was devoted to producing a high resolution bathymetric map that also aimed to estimate the amount and location of the active exhalative centers and their variations in space and time. Data were obtained by three RTK multibeam surveys performed between December 2002 and December 2003. Here we show and discuss the technical details of the bathymetric surveys, the bathymetric map at 0.5 m resolution, and the accurate location of the 606 main exhalative centres active during the 2002-2003 crisis. The bathymetric data and the maps show two prevailing principal NE-SW and NW-SE alignments that match the spatial distribution of the exhalation centres. The accurate positioning at submeter accuracy of the gas vents is useful in the monitoring activity and to study their temporal and spatial variability.

  15. Eruptions of the last 2200 years at Vulcano and Vulcanello (Aeolian Islands, Italy) dated by high-accuracy archeomagnetism

    Science.gov (United States)

    Arrighi, Simone; Tanguy, Jean-Claude; Rosi, Mauro

    2006-12-01

    The recent eruptive history of the Vulcano island (Southern Italy) was investigated through the high-accuracy "large sample" archeomagnetic method (Tanguy, J.C., Le Goff, M., Principe, C., Arrighi, S., Chillemi, V., Paiotti, A., La Delfa, S., Patanè, G., 2003. Archeomagnetic dating of Mediterranean volcanics of the last 2100 years: validity and limits. Earth Planet. Sci. Lett. 211, 111-124; Tanguy, J.C., Principe, C., Arrighi, S., 2005. Comment on "Historical measurements of the Earth's magnetic field compared with remanence directions from lava flows in Italy over the last four centuries" by R. Lanza, A. Meloni, and E. Tema. Phys. Earth Planet. Interiors 152, 116-120; Arrighi, S., 2004. The large sample archeomagnetic method applied to Neapolitan volcanoes and Aeolian Islands. PhD Thesis. University of Pisa, Italy, pp. 1-186). Age determination is based upon directional geomagnetic variation reconstructed from historically dated lavas in Southern Italy, and from archeological sites in Western Europe (Gallet, Y., Genevey, A., Le Goff, M., 2002. Three millennia of directional variation of the Earth's magnetic field in Western Europe as revealed by archeological artefacts. Phys. Earth Planet. Interiors 131, 81-89) relocated to Sicily. Results in the present paper were obtained on 12 sites including 185 samples weighing 0.5-1 kg, distributed over the Vulcanello platform lavas and pyroclastic cones, and on the lava flows from the Fossa cone. It is shown that the Vulcanello platform was built by nearly continuous activity between AD 1000 and 1250, which is more than a millennium younger than believed until now from questionable interpretation of imprecise historical accounts. Most of the lavas from the Fossa cone, whose ages were rather hypothetical or known with a large uncertainty, have erupted within the same period. However, the last "Pietre Cotte" obsidian flow is confirmed to date from 1720 ± 30, in agreement with historical data (1739).

  16. New geological insights and structural control on fluid circulation in La Fossa cone (Vulcano, Aeolian Islands, Italy)

    Science.gov (United States)

    Barde-Cabusson, S.; Finizola, A.; Revil, A.; Ricci, T.; Piscitelli, S.; Rizzo, E.; Angeletti, B.; Balasco, M.; Bennati, L.; Byrdina, S.; Carzaniga, N.; Crespy, A.; Di Gangi, F.; Morin, J.; Perrone, A.; Rossi, M.; Roulleau, E.; Suski, B.; Villeneuve, N.

    2009-09-01

    Electric resistivity tomography (ERT), self-potential (SP), soil CO 2 flux, and temperature are used to study the inner structure of La Fossa cone (Vulcano, Aeolian Islands). Nine profiles were performed across the cone with a measurement spacing of 20 m. The crater rims of La Fossa cone are underlined by sharp horizontal resistivity contrasts. SP, CO 2 flux, and temperature anomalies underline these boundaries which we interpret as structural limits associated to preferential circulation of fluids. The Pietre Cotte crater and Gran Cratere crater enclose the main hydrothermal system, identified at the centre of the edifice on the base of low electrical resistivity values (<20 Ω m) and strong CO 2 degassing, SP, and temperature anomalies. In the periphery, the hydrothermal activity is also visible along structural boundaries such as the Punte Nere, Forgia Vecchia, and Palizzi crater rims and at the base of the cone, on the southern side of the edifice, along a fault attributed to the NW main tectonic trend of the island. Inside the Punte Nere crater, the ERT sections show an electrical resistive body that we interpret as an intrusion or a dome. This magmatic body is reconstructed in 3D using the available ERT profiles. Its shape and position, with respect to the Pietre Cotte crater fault, allows replacing this structure in the chronology of the development of the volcano. It corresponds to a late phase of activity of the Punte Nere edifice. Considering the position of the SP, soil CO 2 flux, and temperature maxima and the repartition of conductive zones related to hydrothermal circulation with respect to the main structural features, La Fossa cone could be considered as a relevant example of the strong influence of pre-existing structures on hydrothermal fluid circulation at the scale of a volcanic edifice.

  17. Insights Into The Dynamics Of Aeolian Volcanic Islands From DInSAR COSMO-SkyMed Observations

    Science.gov (United States)

    Solaro, Giuseppe; Castaldo, Raffaele; Casu, Francesco; De Luca, Claudio; Marsella, Maria; Pepe, Antonio; Pepe, Susi; Ruch, Joel; Sansosti, Eugenio; Scifoni, Silvia; Tizzani, Pietro; Zeni, Giovanni

    2014-05-01

    Differential Synthetic Aperture Radar Interferometry (DInSAR) is a remote sensing technique that allows investigating earth surface deformation phenomena (with centimeter to millimeter accuracy) by exploiting the round-trip phase components of Synthetic Aperture Radar (SAR) images relative to an area of interest. In particular, we refer to the Small BAseline Subsets (SBAS) technique, which relies on the use of small baseline differential SAR interferograms and on the application of the singular value decomposition (SVD) method. This technique can generate deformation velocity maps and time-series of the area of interest; moreover, it has the peculiarity to be able to work at two-scale resolution in order to investigate both spatially large deformation phenomena and localized displacements. Here we focus on the Aeolian Islands, one of the most tectonically and magmatically active zone in the Mediterranean Sea area, hosting several active volcanoes. We present preliminary results on deformation field on Lipari, Vulcano and Stromboli islands by exploiting COSMO-SkyMed (CSK) data both from ascending and descending orbits, generating time series extending from 2008 to 2013. We further combined ascending and descending data (low resolution, 20 meters) in order to separate the vertical and horizontal components of the deformation velocity. First results show that all the three islands are deforming. Lipari is principally affected by non-volcanic deformation such as gravitational instability phenomena mainly located in correspondence of coastal cliffs. On Vulcano island, we observed subsidence of the volcano La Fossa of about 4-5 cm/yr and also gravitational instability phenomena. However, the most important deformation feature is found on Stromboli along 'La Sciara del Fuoco' feature, in correspondence of lava flows. In this case, we observed subsidence of few cm/yr. By comparing InSAR results with recent structural data collected on the field at Lipari and Vulcano, we

  18. Socio-economic baseline assessment: Thayawthatangyi and Langan Islands, Myeik Archipelago, Myanmar

    OpenAIRE

    Schneider, H; Thiha, S.; Pontillas, M.; Ponce de Leon, E.M.

    2015-01-01

    This report details the methodology and results of a 2014 socio-economic baseline assessment of 4 villages in the Myeik Archipelago, Myanmar undertaken as part of a programme to build local stakeholders capacity to use data to inform marine resource planning and managemnt

  19. Island mass effect in the Juan Fernández Archipelago (33°S), Southeastern Pacific

    Science.gov (United States)

    Andrade, Isabel; Sangrà, Pablo; Hormazabal, Samuel; Correa-Ramirez, Marco

    2014-02-01

    Spatial and temporal variability of the island mass effect (IME; defined as local increases of phytoplankton associated with the presence of islands) at the Juan Fernández Archipelago (JFA) is analyzed using chlorophyll-a (Chl-a) satellite data, altimetry, sea surface temperature, wind, geostrophic currents and net heat flux over a ten year period (2002-2012). The the JFA islands (Robinson Crusoe-Santa Clara (RC-SC) and Alejandro Selkirk (AS)) present wakes with significant Chl-a increases, mainly during spring time. These wakes can reach Chl-a values of one order of magnitude higher (~1 mg m-3) than the surrounding oligotrophic waters (<0.1 mg m-3). The wakes are similar to von Kármán vortex streets which have been used to explain the impact of IME on Chl-a increases in numerical models. The wakes are formed from a high productivity area in the lee of the island, extending to the oceanic region as high Chl-a patches associated with submesoscale eddies that are detached from the islands and connected by less-productive zones. This pattern coincides with previous models that predict the effects of island-generated flow perturbations on biological production variability. The IME is a recurrent feature of islands that has even been observed in decadal average fields. In such average fields, the Chl-a values in RC-SC and AS islands can exceed values found in a Control Zone (a zone without islands) by ~50% and 30%, respectively. Seasonal and interannual variability reveals that, as a consequence of the IME, the winter Chl-a maximum associated with the development of winter convection and mesoscale eddies that propagate from the continental zone, promote that the Chl-a maximum extends towards spring. The IME has an impact on the island on both a local as well as a more regional scale that affects an area of ~40,000 km2 (1°Latitude×4°Longitude) centered on the islands. The transport of high productivity patches associated with submesoscale eddies may be responsible

  20. Multisensor and multitemporal data from Landsat images to detect damage to coral reefs, small islands in the Spermonde archipelago, Indonesia

    Science.gov (United States)

    Nurdin, Nurjannah; Komatsu, Teruhisa; Agus; Akbar AS, M.; Djalil, Abdul Rasyid; Amri, Khairul

    2015-06-01

    Coral reefs are important because of their high biodiversity and their key role in the tropical marine biosphere. Furthermore, coral reefs are very valuable as a socioeconomic resource as they make important contributions to the gross domestic product of many countries. Thus, it is very important to monitor dynamic spatial distributions of coral reefs and related habitats dominated by coral rubble, dead coral, and bleached corals. Despite these natural and socio-economic advantages, many factors are threatening coral reefs. The study site was selected in Spermonde archipelago, South Sulawesi, Indonesia because this area is included in the Coral Triangle, recognized as the epicenter of coral diversity and a priority for conservation. Images of Landsat MSS, Landsat TM, Landsat ETM, Landsat ETM+, and Landsat 8 data were used to examine changes in the coral reefs of Suranti Island in the Spermonde Archipelago during forty one years from 1972 to 2013. The image processing includes gap fills, atmospheric corrections, geometric corrections, image composites, water column corrections, unsupervised classifications, and reclassifications. Fill Gap processing was done on Landsat ETM+ SLC-off. Subsequently, a multi-component change detection procedure was applied to define changes. Shallow water bottom types classification was divided into live coral, rubble and sand habitats, dead coral with algae, rubble, and sand. Preliminary results showed significant changes during the period 1972-2013 as well as changes in coral reefs, likely explained partly by destructive fishing practices.

  1. Conservation genetics of the Philippine tarsier: cryptic genetic variation restructures conservation priorities for an island archipelago primate.

    Science.gov (United States)

    Brown, Rafe M; Weghorst, Jennifer A; Olson, Karen V; Duya, Mariano R M; Barley, Anthony J; Duya, Melizar V; Shekelle, Myron; Neri-Arboleda, Irene; Esselstyn, Jacob A; Dominy, Nathaniel J; Ong, Perry S; Moritz, Gillian L; Luczon, Adrian; Diesmos, Mae Lowe L; Diesmos, Arvin C; Siler, Cameron D

    2014-01-01

    Establishment of conservation priorities for primates is a particular concern in the island archipelagos of Southeast Asia, where rates of habitat destruction are among the highest in the world. Conservation programs require knowledge of taxonomic diversity to ensure success. The Philippine tarsier is a flagship species that promotes environmental awareness and a thriving ecotourism economy in the Philippines. However, assessment of its conservation status has been impeded by taxonomic uncertainty, a paucity of field studies, and a lack of vouchered specimens and genetic samples available for study in biodiversity repositories. Consequently, conservation priorities are unclear. In this study we use mitochondrial and nuclear DNA to empirically infer geographic partitioning of genetic variation and to identify evolutionarily distinct lineages for conservation action. The distribution of Philippine tarsier genetic diversity is neither congruent with expectations based on biogeographical patterns documented in other Philippine vertebrates, nor does it agree with the most recent Philippine tarsier taxonomic arrangement. We identify three principal evolutionary lineages that do not correspond to the currently recognized subspecies, highlight the discovery of a novel cryptic and range-restricted subcenter of genetic variation in an unanticipated part of the archipelago, and identify additional geographically structured genetic variation that should be the focus of future studies and conservation action. Conservation of this flagship species necessitates establishment of protected areas and targeted conservation programs within the range of each genetically distinct variant of the Philippine tarsier.

  2. Phylogeny of the island archipelago frog genus Sanguirana: Another endemic Philippine radiation that diversified 'Out-of-Palawan'.

    Science.gov (United States)

    Brown, Rafe M; Su, Yong-Chao; Barger, Brenna; Siler, Cameron D; Sanguila, Marites B; Diesmos, Arvin C; Blackburn, David C

    2016-01-01

    Recent higher-level frog phylogenetic analyses have included a few members of the endemic Philippine frog genus Sanguirana. Although the monophyly of the group has never been disputed, the recent phylogenetically-supported inclusion of the Palawan Wood Frog (Sanguirana sanguinea) in this clade was highly unexpected. In addition, species boundaries and relationships remain unclear and new species continue to be discovered. We estimate the phylogeny for this endemic Philippine genus using two mitochondrial gene regions and six nuclear loci and complete sampling for all known species. We use a time-calibrated Bayesian estimate of phylogeny and model-testing approach to biogeographic inference to infer ancestral areas and probable means of diversification. These analyses identify Sanguirana as an additional clade for which the 'Out-of-Palawan' biogeographic scenario is unambiguously preferred. This study lends additional support to recent work suggesting that a substantial portion of Philippine vertebrate megadiversity originated via colonization of the archipelago from the Palawan microcontinent, with subsequent invasion of oceanic islands (e.g., range expansion over Huxley's Modification of Wallace's Line), numerous instances of overwater dispersal, and geographic radiation across the archipelago.

  3. Natural {gamma}-radiation of rocks and soils from Vulcano (Aeolian Islands, Mediteranean Sea)

    Energy Technology Data Exchange (ETDEWEB)

    Brai, M. [Palermo Univ. (Italy). Ist. della Biocomunicazione; Hauser, S.; Bellia, S. [Palermo Univ. (Italy). Ist. di Mineralogia, Petrografia e Geochimica; Puccio, P.; Rizzo, S. [Palermo Univ. (Italy). Dipt. di Ingegneria Nucleare

    1995-04-01

    Gamma-ray spectra of the main lithotypes and soils from Vulcano island (Mediterranean Sea) have been carried out in order to quantify the natural radioactivity. The {sup 238}U, {sup 232}Th, and {sup 40}K contents obtained are in agreement with the genesis of the rock formation. In fact, basaltic rocks showed the lowest content of radionuclides whereas the rhyolitic rocks showed the highest concentrations. The results are comparable with other volcanic areas of southern Italy. Measurements of absorbed dose in air by TL dosimeters were also performed. The values ranged between 0.5 and 2.0 mGy y{sup -1}. Comparison between these values and those computed from {gamma}-ray spectra showed a good correlation. (author).

  4. Understanding and mapping local conflicts related to protected areas in small islands: a case study of the Azores archipelago

    Directory of Open Access Journals (Sweden)

    Chiara Bragagnolo

    2016-05-01

    Full Text Available Establishing Protected Areas (PAs is considered one of the most appropriate ways to conserve nature and cultural landscapes. However, conservation constraints can generate social conflicts, especially at a local level. In small islands (SIs, local conflicts may escalate due to an increase in competition for limited space and resources. Pico island in the Azores Archipelago (Portugal, part of the Outermost European region, was considered a good case to study conservation-development conflicts due to the amount of designated protected land (> 35% of its surface and the approval of a new Azorean PA network in 2007. This paper presents a new approach to understanding and mapping local conflicts within PAs in SIs by integrating qualitative data and spatially explicit information. This research takes stock of the benefits, needs and constraints related to Pico Natural Park as perceived by local stakeholders through face-to-face semi-structured interviews; it subsequently identifies and transposes the conflicts distilled from stakeholder discourse into spatially representative visual maps via GIS. Research outcomes show that PAs are perceived mainly as constraints to local development, showing inconsistency between local expectations and regional conservation policy. This highlights the importance of including public participation processes prior to any implementation of conservation strategies. The proposed method provides a springboard towards effective conflict management for PAs on Pico island, showing a relatively low-cost and straightforward approach to minimising future local conflicts which could be adapted to other similar Outermost European regions and SIs.

  5. Distribution of Thelastomatoid Nematodes (Nematoda: Oxyurida) in Endemic and Introduced Cockroaches on the Galápagos Island Archipelago, Ecuador.

    Science.gov (United States)

    Sinnott, Devinn; Carreno, Ramon A; Herrera, Henri

    2015-08-01

    The thelastomatoid pinworm fauna (Nematoda: Oxyurida: Thelastomatoidea) was surveyed in 3 endemic species and 6 introduced species of cockroach hosts (Insecta: Blattaria) in the Galápagos Islands, Ecuador. A total of 658 host specimens were examined from preserved collections that had been collected between 1966 and 2003 from 7 islands in the archipelago. Eight species of pinworms were identified from these cockroach hosts, including the dominant species Cephalobellus ovumglutinosus and a Severianoia sp. as well as Leidynema appendiculata, Hammerschmidtiella diesingi, an unidentified Cephalobellus species resembling Cephalobellus magalhaesi, an unidentified Protrellus species closely resembling Protrellus shamimi, and an undescribed Blattophila sp. Five new host records are identified for C. ovumglutinosus including the endemic Galápagos cockroaches Chorisoneura carpenteri, Ischnoptera snodgrassii, and Ischnoptera santacruzensis. These endemics were also infected with an undescribed Blatticola sp. Other species recorded resemble known pinworms from other hosts around the world. Prevalence between islands and between host species was variable, but total prevalence for individual pinworm species was consistently low (<10%). A single host specimen examined was infected with more than 1 pinworm species; otherwise only a single species was observed in each infected host. At least 1 introduced pinworm species carried to the islands via invasive cockroach hosts was present in endemic host species, but several globally widespread introduced pinworm species were absent from endemic cockroaches. Santa Cruz was inhabited by the greatest number of pinworm species, likely due to a higher rate of invasive host introduction. This survey, the first from this region, showed that the distribution and transmission of pinworms in the Galápagos Islands is complex and may provide future models of invertebrate dispersal and speciation in an ecosystem already rich with examples of

  6. A population genetic assessment of coral recovery on highly disturbed reefs of the Keppel Island archipelago in the southern Great Barrier Reef.

    Science.gov (United States)

    van Oppen, Madeleine J H; Lukoschek, Vimoksalehi; Berkelmans, Ray; Peplow, Lesa M; Jones, Alison M

    2015-01-01

    Coral reefs surrounding the islands lying close to the coast are unique to the Great Barrier Reef (GBR) in that they are frequently exposed to disturbance events including floods caused by cyclonic rainfall, strong winds and occasional periods of prolonged above-average temperatures during summer. In one such group of islands in the southern GBR, the Keppel Island archipelago, climate-driven disturbances frequently result in major coral mortality. Whilst these island reefs have clearly survived such dramatic disturbances in the past, the consequences of extreme mortality events may include the loss of genetic diversity, and hence adaptive potential, and a reduction in fitness due to inbreeding, especially if new recruitment from external sources is limited. Here we examined the level of isolation of the Keppel Island group as well as patterns of gene flow within the Keppel Islands using 10 microsatellite markers in nine populations of the coral, Acropora millepora. Bayesian cluster analysis and assignment tests indicated gene flow is restricted, but not absent, between the outer and inner Keppel Island groups, and that extensive gene flow exists within each of these island groups. Comparison of the Keppel Island data with results from a previous GBR-wide study that included a single Keppel Island population, confirmed that A. millepora in the Keppel Islands is genetically distinct from populations elsewhere on the GBR, with exception of the nearby inshore High Peak Reef just north of the Keppel Islands. We compared patterns of genetic diversity in the Keppel Island populations with those from other GBR populations and found them to be slightly, but significantly lower, consistent with the archipelago being geographically isolated, but there was no evidence for recent bottlenecks or deviation from mutation-drift equilibrium. A high incidence of private alleles in the Keppel Islands, particularly in the outer islands, supports their relative isolation and contributes

  7. A population genetic assessment of coral recovery on highly disturbed reefs of the Keppel Island archipelago in the southern Great Barrier Reef

    Directory of Open Access Journals (Sweden)

    Madeleine J.H. van Oppen

    2015-07-01

    Full Text Available Coral reefs surrounding the islands lying close to the coast are unique to the Great Barrier Reef (GBR in that they are frequently exposed to disturbance events including floods caused by cyclonic rainfall, strong winds and occasional periods of prolonged above-average temperatures during summer. In one such group of islands in the southern GBR, the Keppel Island archipelago, climate-driven disturbances frequently result in major coral mortality. Whilst these island reefs have clearly survived such dramatic disturbances in the past, the consequences of extreme mortality events may include the loss of genetic diversity, and hence adaptive potential, and a reduction in fitness due to inbreeding, especially if new recruitment from external sources is limited. Here we examined the level of isolation of the Keppel Island group as well as patterns of gene flow within the Keppel Islands using 10 microsatellite markers in nine populations of the coral, Acropora millepora. Bayesian cluster analysis and assignment tests indicated gene flow is restricted, but not absent, between the outer and inner Keppel Island groups, and that extensive gene flow exists within each of these island groups. Comparison of the Keppel Island data with results from a previous GBR-wide study that included a single Keppel Island population, confirmed that A. millepora in the Keppel Islands is genetically distinct from populations elsewhere on the GBR, with exception of the nearby inshore High Peak Reef just north of the Keppel Islands. We compared patterns of genetic diversity in the Keppel Island populations with those from other GBR populations and found them to be slightly, but significantly lower, consistent with the archipelago being geographically isolated, but there was no evidence for recent bottlenecks or deviation from mutation-drift equilibrium. A high incidence of private alleles in the Keppel Islands, particularly in the outer islands, supports their relative

  8. Palaeo-islands as refugia and sources of genetic diversity within volcanic archipelagos: the case of the widespread endemic Canarina canariensis (Campanulaceae).

    Science.gov (United States)

    Mairal, M; Sanmartín, I; Aldasoro, J J; Culshaw, V; Manolopoulou, I; Alarcón, M

    2015-08-01

    Geographical isolation by oceanic barriers and climatic stability has been postulated as some of the main factors driving diversification within volcanic archipelagos. However, few studies have focused on the effect that catastrophic volcanic events have had on patterns of within-island differentiation in geological time. This study employed data from the chloroplast (cpDNA haplotypes) and the nuclear (AFLPs) genomes to examine the patterns of genetic variation in Canarina canariensis, an iconic plant species associated with the endemic laurel forest of the Canary Islands. We found a strong geographical population structure, with a first divergence around 0.8 Ma that has Tenerife as its central axis and divides Canarian populations into eastern and western clades. Genetic diversity was greatest in the geologically stable 'palaeo-islands' of Anaga, Teno and Roque del Conde; these areas were also inferred as the ancestral location of migrant alleles towards other disturbed areas within Tenerife or the nearby islands using a Bayesian approach to phylogeographical clustering. Oceanic barriers, in contrast, appear to have played a lesser role in structuring genetic variation, with intra-island levels of genetic diversity larger than those between-islands. We argue that volcanic eruptions and landslides after the merging of the palaeo-islands 3.5 Ma played key roles in generating genetic boundaries within Tenerife, with the palaeo-islands acting as refugia against extinction, and as cradles and sources of genetic diversity to other areas within the archipelago.

  9. Signs of potential renewal of eruptive activity at La Fossa (Vulcano, Aeolian Islands)

    Science.gov (United States)

    Montalto, A.

    1996-04-01

    Since the end of the last magmatic eruption (1890), activity of La Fossa (southern Tyrrhenian Sea, Italy) has consisted of fumarolic emissions of fluctuating intensity. Fluids are discharged principally at two fumarolic fields located in the northern rim of the active crater and at the beach sited at its northern foot. Increased thermal, seismic and geochemical activity has been recorded since 1978, when an earthquake of M=5.5 occurred in the region. This paper combines available geophysical and geochemical information in order to develop a tentative interpretation of two episodes of apparent unrest which occurred in 1985 and 1987 1988, enhancing the risk of renewal of the eruptive activity. The 1985 unrest consisted essentially of a sharp build up of the internal pressure in the shallow hydrothermal system, which was induced by the injection of hot gases of magmatic origin. The crater fumaroles displayed significant increases in CO2 and other acid species, but their outlet temperature did not change. Conversely, the 1987 1988 episode was characterized by appreciable modifications at the crater fumaroles, with only secondary effects at the fumarole system of the beach. The sliding of part of the eastern flank of the La Fossa cone into the sea occurred on 20 April 1988, when the region was affected by crustal dilatation producing a seismic sequence of relatively high intensity. Both episodes of unrest were accompanied by increases of local microseismic activity, which affected the nothern sector of the island in 1985, and the southern one in 1988. Finally, a phase of appreciable areal contraction was detected in 1990, probably due to the effect of the cooling and crystallization of magma at relatively shallow depths, accompanying the increased thermal activity at the crater fumaroles. Regional tectonic stress seems to play an important role in the transition of the volcanic system from a phase of relative stability to a phase of apparent unrest, inducing the heating

  10. Volcanic history of Lipari (Aeolian Islands, Italy) during the last 10,000 years

    Science.gov (United States)

    Cortese, M.; Frazzetta, G.; La Volpe, L.

    1986-01-01

    Examination of the volcanic stratigraphy of deposits younger than 10,000 years on Lipari indicates four principal periods of volcanic activity related to specific centers. The products from each different volcanic center are defined as volcano-stratigraphic unit (VSU). From the oldest these are: the Canneto Dentro, Gabellotto-Fiume Bianco, Forgia Vecchia and Monte Pilato-Rocche Rosse VSUs. The study of textures and dispersal of the deposits permitted the vents to be localized and the recent volcanic history of Lipari to be reconstructed. The oldest event formed a small explosion breccia cone with a final obsidian lava in the Canneto Dentro area. Immediately afterward, a complex series of explosions produced the widespread dry-surge deposits of the Gabellotto-Fiume Bianco sequence. This activity ended with the extrusion of a domical lava flow. The renewal of activity occurred in the Pirrera area with an explosive eruption that produced explosion breccia deposits. The last eruptions from this vent were coeval with the first eruption of M. Pilato. The rim of the explosion breccia cone was partially destroyed by the Forgia Vecchia lava flow. M. Pilato cone grew in a very short period of time due to a continuous swarm of explosive events. After a short repose time, a series of more energetic and superficial explosions occurred through a vent slightly to the south. The extrusion of the Rocche Rosse lava flow (about 729 A.D.) ended this cycle of activity. All the volcanic centers follow a quite similar stochastic pattern starting with a fall or surge eruption and ending with effusion of viscous rhyolitic lavas. The four centers are aligned along either NW-SE or NE-SW fault systems according to the structural pattern of the island. They can be placed into two groups: the Canneto Dentro-Gabellotto centers and the Forgia Vecchia-M. Pilato centers. A long quiescence ( ⋍ 3,500 years) separates the activity of these two groups while inside of each the activities were nearly

  11. Grain-size features of aeolian sand on the east coast of Hainan Island and the revealed evolutionary processes of the sedimentary environment

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Mudui stratigraphic section represents the typical records of sedimentation processes of sand dunes and interdune depressions on the east coast of Hainan Island.Based on high-density sampling and optically stimulated luminescence(OSL) dating of the strata of the section,the grain-size composition,grain-size parameters,cumulative distribution probability curve,and grain-size-sensitivity indexes(SC/D) were analyzed.The analyzed results show that the grain-size features of aeolian sand,weakly developed sandy paleosol,two-facies(aeolian and aqueous) deposits,and lagoon deposits are all different.This indicates four evolutionary phases of the sedimentary environment of the east coast of Hainan Island since 38 ka B.P.Phase I:38-22 ka B.P.;phase II:22-17 ka B.P.;phase III:17-10 ka B.P.;phase IV:10 ka B.P.-present.The climate experienced the hot-wet/hot-dry,hot-wet/hot-dry,and warm-wet/hot-wet fluctuations,and the sedimentary environment also underwent lagoon deposition,dune and interdune depression deposition,dune stabilization and soil development,shifting sand deposition,and evolutionary processes.

  12. Description of the atmospheric circulation in the boundary layer over a tropical island: Case study of Guadeloupe Archipelago

    Science.gov (United States)

    Plocoste, Thomas; Dorville, Jean-François; Jacoby-Koaly, Sandra; Roussas, André

    2016-04-01

    Over past two decades the use of atmospheric sounding methods as Sodars, Lidar equipped drones increased sharply. Compare to weather balloon, these modern methods allow measure of profile at constant heights during long period. There are few studies using this type of equipment in tropical climates and lesser on small island. Wind regime on island of diameter less than 50 km are mostly considered as oceanic. Many author consider that thermal effect are negligible in land. But recent observations and simulations show importance of the thermal circulation at small- and meso- scales particularly in atmospheric pollution process. Up to 2009 no wind profile data were available continuously to study atmospheric circulation in Guadeloupe Archipelago (GA) which is one of the islands of the Lesser Antilles Arc. In first approximation wind was evaluated based on measures done at the most upwind island of the GA for many application as wind power and atmospheric pollution. From 2009 to 2012 a measurement campaign of the Atmospheric Boundary Layer (ABL) have been performed by the University of Antilles (UA) in GA. To assess effects of dynamic of ABL on air quality in sub urban area, particularly during the sunset and sunrise, UA monitored two sites with a weather station and a doppler sodar (REMTECH PAO). Both sites are close to the sea with one in a coastal area and the other in an open landfill surrounded by densely populated building and a mangrove swamp. Thermal and chemical measurements with a portable mass spectrometer were made in the vicinity of the landfill and showed the existence of urban heat islands. This study presents the first Doppler Sodar long measurements campaign in GA. Statistical analysis of the three year of doppler sodar data (i.e. wind components and its fluctuations) allow to identified and characterized the complex circulations on the two sites in the ABL between 25 and 500m above the sea level. Orographic and thermal effects due to urban area were

  13. CRED Towed-Diver Fish Biomass Surveys at Guam Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  14. CRED Towed-Diver Fish Biomass Surveys at Tinian Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  15. CRED Towed-Diver Fish Biomass Surveys at Rota Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  16. CRED Towed-Diver Fish Biomass Surveys at Aguijan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  17. CRED Towed-Diver Fish Biomass Surveys at Agrihan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  18. CRED Towed-Diver Fish Biomass Surveys at Guam Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  19. CRED Towed-Diver Fish Biomass Surveys at Guguan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  20. CRED Towed-Diver Fish Biomass Surveys at Tinian Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  1. CRED Towed-Diver Fish Biomass Surveys at Rota Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  2. CRED Towed-Diver Fish Biomass Surveys at Anatahan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  3. CRED Towed-Diver Fish Biomass Surveys at Saipan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  4. CRED Towed-Diver Fish Biomass Surveys at Farallon De Pajaros Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  5. CRED Towed-Diver Fish Biomass Surveys at Sarigan Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  6. CRED Towed-Diver Fish Biomass Surveys at Pagan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  7. CRED Towed-Diver Fish Biomass Surveys at Asuncion Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  8. CRED Towed-Diver Fish Biomass Surveys at Asuncion Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  9. CRED Towed-Diver Fish Biomass Surveys at Farallon De Pajaros Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  10. CRED Towed-Diver Fish Biomass Surveys at Saipan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  11. CRED Towed-Diver Fish Biomass Surveys at Aguijan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  12. CRED Towed-Diver Fish Biomass Surveys at Agrihan Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  13. CRED REA Algal Assessments at Asuncion Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 3 sites at Asuncion Island...

  14. CRED Towed-Diver Fish Biomass Surveys at Maug Islands, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  15. CRED Towed-Diver Fish Biomass Surveys at Guguan Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  16. CRED REA Algal Assessments at Agrihan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 4 sites at Agrihan Island...

  17. CRED Towed-Diver Fish Biomass Surveys at Guam Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  18. CRED Towed-Diver Fish Biomass Surveys at Guguan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  19. CRED Towed-Diver Fish Biomass Surveys at Sarigan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  20. CRED REA Algal Assessments at Uracas Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 3 sites at Uracas Island...

  1. CRED REA Algal Assessments at Maug Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 9 sites at Maug Island in...

  2. CRED REA Algal Assessments at Aguijan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 3 sites at Aguijan Island...

  3. CRED REA Algal Assessments at Tinian Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 6 sites at Tinian Island...

  4. CRED REA Algal Assessments at Rota Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 6 sites at Rota Island in...

  5. CRED REA Algal Assessments at Guguan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 2 sites at Guguan Island...

  6. CRED REA Algal Assessments at Pagan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 10 sites at Pagan Island...

  7. CRED REA Algal Assessments at Alamagan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 3 sites at Alamagan Island...

  8. CRED REA Algal Assessments at Sarigan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 3 sites at Sarigan Island...

  9. CRED REA Algal Assessments at Saipan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of Rapid Ecological Assessments (REA), Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, conducted at 8 sites at Saipan Island...

  10. CRED Towed-Diver Fish Biomass Surveys at Rota Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  11. CRED Towed-Diver Fish Biomass Surveys at Asuncion Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  12. CRED Towed-Diver Fish Biomass Surveys at Rota Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  13. CRED Towed-Diver Fish Biomass Surveys at Alamagan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  14. CRED Towed-Diver Fish Biomass Surveys at Maug Islands, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  15. CRED Towed-Diver Fish Biomass Surveys at Guguan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  16. CRED Towed-Diver Fish Biomass Surveys at Sarigan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  17. CRED Towed-Diver Fish Biomass Surveys at Aguijan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  18. CRED Towed-Diver Fish Biomass Surveys at Alamagan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  19. CRED Towed-Diver Fish Biomass Surveys at Saipan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  20. CRED Towed-Diver Fish Biomass Surveys at Sarigan Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  1. CRED Towed-Diver Fish Biomass Surveys at Alamagan Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  2. CRED Towed-Diver Fish Biomass Surveys at Maug Islands, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  3. CRED Towed-Diver Fish Biomass Surveys at Tinian Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  4. CRED Towed-Diver Fish Biomass Surveys at Pagan Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC)...

  5. CRED Towed-Diver Fish Biomass Surveys at Asuncion Island, Marianas Archipelago in 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  6. CRED Towed-Diver Fish Biomass Surveys at Pagan Island, Marianas Archipelago in 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  7. CRED Towed-Diver Fish Biomass Surveys at Aguijan Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  8. CRED Towed-Diver Fish Biomass Surveys at Alamagan Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  9. CRED Towed-Diver Fish Biomass Surveys at Farallon De Pajaros Island, Marianas Archipelago in 2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  10. CRED Towed-Diver Fish Biomass Surveys at Maug Islands, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  11. CRED Towed-Diver Fish Biomass Surveys at Farallon De Pajaros Island, Marianas Archipelago in 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Towed-diver surveys (aka. Towboard surveys) are conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as...

  12. Abundance and Distribution of Sperm Whales in the Canary Islands: Can Sperm Whales in the Archipelago Sustain the Current Level of Ship-Strike Mortalities?

    Directory of Open Access Journals (Sweden)

    Andrea Fais

    Full Text Available Sperm whales are present in the Canary Islands year-round, suggesting that the archipelago is an important area for this species in the North Atlantic. However, the area experiences one of the highest reported rates of sperm whale ship-strike in the world. Here we investigate if the number of sperm whales found in the archipelago can sustain the current rate of ship-strike mortality. The results of this study may also have implications for offshore areas where concentrations of sperm whales may coincide with high densities of ship traffic, but where ship-strikes may be undocumented. The absolute abundance of sperm whales in an area of 52933 km2, covering the territorial waters of the Canary Islands, was estimated from 2668 km of acoustic line-transect survey using Distance sampling analysis. Data on sperm whale diving and acoustic behaviour, obtained from bio-logging, were used to calculate g(0 = 0.92, this is less than one because of occasional extended periods when whales do not echolocate. This resulted in an absolute abundance estimate of 224 sperm whales (95% log-normal CI 120-418 within the survey area. The recruitment capability of this number of whales, some 2.5 whales per year, is likely to be exceeded by the current ship-strike mortality rate. Furthermore, we found areas of higher whale density within the archipelago, many coincident with those previously described, suggesting that these are important habitats for females and immature animals inhabiting the archipelago. Some of these areas are crossed by active shipping lanes increasing the risk of ship-strikes. Given the philopatry in female sperm whales, replacement of impacted whales might be limited. Therefore, the application of mitigation measures to reduce the ship-strike mortality rate seems essential for the conservation of sperm whales in the Canary Islands.

  13. Abundance and Distribution of Sperm Whales in the Canary Islands: Can Sperm Whales in the Archipelago Sustain the Current Level of Ship-Strike Mortalities?

    Science.gov (United States)

    Fais, Andrea; Lewis, Tim P; Zitterbart, Daniel P; Álvarez, Omar; Tejedor, Ana; Aguilar Soto, Natacha

    2016-01-01

    Sperm whales are present in the Canary Islands year-round, suggesting that the archipelago is an important area for this species in the North Atlantic. However, the area experiences one of the highest reported rates of sperm whale ship-strike in the world. Here we investigate if the number of sperm whales found in the archipelago can sustain the current rate of ship-strike mortality. The results of this study may also have implications for offshore areas where concentrations of sperm whales may coincide with high densities of ship traffic, but where ship-strikes may be undocumented. The absolute abundance of sperm whales in an area of 52933 km2, covering the territorial waters of the Canary Islands, was estimated from 2668 km of acoustic line-transect survey using Distance sampling analysis. Data on sperm whale diving and acoustic behaviour, obtained from bio-logging, were used to calculate g(0) = 0.92, this is less than one because of occasional extended periods when whales do not echolocate. This resulted in an absolute abundance estimate of 224 sperm whales (95% log-normal CI 120-418) within the survey area. The recruitment capability of this number of whales, some 2.5 whales per year, is likely to be exceeded by the current ship-strike mortality rate. Furthermore, we found areas of higher whale density within the archipelago, many coincident with those previously described, suggesting that these are important habitats for females and immature animals inhabiting the archipelago. Some of these areas are crossed by active shipping lanes increasing the risk of ship-strikes. Given the philopatry in female sperm whales, replacement of impacted whales might be limited. Therefore, the application of mitigation measures to reduce the ship-strike mortality rate seems essential for the conservation of sperm whales in the Canary Islands.

  14. Geography, deer, and host biodiversity shape the pattern of Lyme disease emergence in the Thousand Islands Archipelago of Ontario, Canada.

    Science.gov (United States)

    Werden, Lisa; Barker, Ian K; Bowman, Jeff; Gonzales, Emily K; Leighton, Patrick A; Lindsay, L Robbin; Jardine, Claire M

    2014-01-01

    In the Thousand Islands region of eastern Ontario, Canada, Lyme disease is emerging as a serious health risk. The factors that influence Lyme disease risk, as measured by the number of blacklegged tick (Ixodes scapularis) vectors infected with Borrelia burgdorferi, are complex and vary across eastern North America. Despite study sites in the Thousand Islands being in close geographic proximity, host communities differed and both the abundance of ticks and the prevalence of B. burgdorferi infection in them varied among sites. Using this archipelago in a natural experiment, we examined the relative importance of various biotic and abiotic factors, including air temperature, vegetation, and host communities on Lyme disease risk in this zone of recent invasion. Deer abundance and temperature at ground level were positively associated with tick abundance, whereas the number of ticks in the environment, the prevalence of B. burgdorferi infection, and the number of infected nymphs all decreased with increasing distance from the United States, the presumed source of this new endemic population of ticks. Higher species richness was associated with a lower number of infected nymphs. However, the relative abundance of Peromyscus leucopus was an important factor in modulating the effects of species richness such that high biodiversity did not always reduce the number of nymphs or the prevalence of B. burgdorferi infection. Our study is one of the first to consider the interaction between the relative abundance of small mammal hosts and species richness in the analysis of the effects of biodiversity on disease risk, providing validation for theoretical models showing both dilution and amplification effects. Insights into the B. burgdorferi transmission cycle in this zone of recent invasion will also help in devising management strategies as this important vector-borne disease expands its range in North America.

  15. Philopatry drives genetic differentiation in an island archipelago: comparative population genetics of Galapagos Nazca boobies (Sula granti) and great frigatebirds (Fregata minor).

    Science.gov (United States)

    Levin, Iris I; Parker, Patricia G

    2012-11-01

    Seabirds are considered highly mobile, able to fly great distances with few apparent barriers to dispersal. However, it is often the case that seabird populations exhibit strong population genetic structure despite their potential vagility. Here we show that Galapagos Nazca booby (Sula granti) populations are substantially differentiated, even within the small geographic scale of this archipelago. On the other hand, Galapagos great frigatebird (Fregata minor) populations do not show any genetic structure. We characterized the genetic differentiation by sampling five colonies of both species in the Galapagos archipelago and analyzing eight microsatellite loci and three mitochondrial genes. Using an F-statistic approach on the multilocus data, we found significant differentiation between nearly all island pairs of Nazca booby populations and a Bayesian clustering analysis provided support for three distinct genetic clusters. Mitochondrial DNA showed less differentiation of Nazca booby colonies; only Nazca boobies from the island of Darwin were significantly differentiated from individuals throughout the rest of the archipelago. Great frigatebird populations showed little to no evidence for genetic differentiation at the same scale. Only two island pairs (Darwin - Wolf, N. Seymour - Wolf) were significantly differentiated using the multilocus data, and only two island pairs had statistically significant φ(ST) values (N. Seymour - Darwin, N. Seymour - Wolf) according to the mitochondrial data. There was no significant pattern of isolation by distance for either species calculated using both markers. Seven of the ten Nazca booby migration rates calculated between island pairs were in the south or southeast to north or northwest direction. The population differentiation found among Galapagos Nazca booby colonies, but not great frigatebird colonies, is most likely due to differences in natal and breeding philopatry.

  16. A little island with significant groundwater resources: hydrogeological and hydrogeochemical features of the Pianosa aquifer (Tuscan Archipelago, Italy)

    Science.gov (United States)

    Giannecchini, R.; Doveri, M.; Mussi, M.; Nicotra, I.; Puccinelli, A.

    2012-12-01

    The Pianosa Island is one of the seven islands of the Tuscan Archipelago, particularly known for its typical flat morphological structure. It is formed by Neogenic-Quaternary sedimentary rocks, mainly represented by superficial calcarenite and underlying marl and clayey marl. Despite the small extension of the island (just 10,2 km2 wide, coastal perimeter of approximately 18 km, maximum altitude of 29 m a.s.l.) and poor rainfall amount (the annual average is 480,7 mm in 1951-2002 period), the Pianosa aquifer is characterized by significant groundwater resources, which supported the presence of approximately 2,000 people at the end of Eighties. Nevertheless, the groundwater overexploitation and the land use (agricultural activity and cattle-breeding, associated to the local penal settlement activity) caused important sea-water intrusion and pollution phenomena. An improvement of such situation occurs since 1998, owing to the closing of the penal settlement and its activities. This pilot research intends to describe the hydrogeological and hydrogeochemical features of the Pianosa Island aquifer system and the groundwater quality several years after the penal settlement closing. The results of a multidisciplinary approach (hydrogeological, geochemical, isotopic) show that the groundwater recharge and circulation are substantially controlled by the hydro-structural conditions. The flat and permeable superficial calcarenite allows a high infiltration rate. The water table flow direction is generally W-E, in accordance with the dip direction of the stratigraphic contact between the calcarenite and the underlying impermeable marly-clayey rocks. However, the latter present conglomerate and sandstone intercalations, sometimes in contact (by angular unconformity) with the calcarenite, determining a general continuity in groundwater circulation, which is phreatic in the calcarenite, and confined in the conglomerate and sandstone horizons. A piezometric depression with values

  17. On the origin and post-depositional history of widespread massive ash deposits: The case of Intermediate Brown Tuffs (IBT) of Lipari (Aeolian Islands, Italy)

    Science.gov (United States)

    De Rosa, Rosanna; Donato, Paola; Scarciglia, Fabio

    2016-11-01

    We analysed a widespread, massive ash unit outcropping on the island of Lipari, which belongs to the Intermediate Brown Tuffs (IBT) succession of the Aeolian Islands, Italy. The use of a multidisciplinary approach that integrates textural, petrological and pedological methods, allows us to discriminate between syn-eruptive and post-depositional features. The deposits are dominated by uncrystallised blocky glass fragments of homogeneous shoshonitic composition, confirming a provenance from hydromagmatic eruptions on the island of Vulcano. Many glass fragments are surrounded by a coating separated by a thin void of syn-eruptive origin due to alteration by aggressive acid gases in the eruptive cloud. The lack of this coating in the northern part of Lipari can be explained as a progressive dispersion of the gases far from the vent and/or to post-depositional processes. The degree of soil development significantly increases from south (soil profiles P1 and P2 at Valle Muria) to north (P3 and P4, at Madoro and Chiesa Vecchia sites, respectively) as a response to a decrease in slope steepness, which has brought about a progressive deepening of the pedogenetic front on gentler landforms and conversely its rejuvenation on steep slopes. The relatively poor to moderate degree of pedogenic evolution of the studied IBT unit is consistent with its emplacement during part of the last glacial period.

  18. Lyme borreliosis spirochetes and spotted fever group rickettsiae in ixodid ticks from Pianosa island, Tuscany Archipelago, Italy.

    Science.gov (United States)

    Tomassone, L; Grego, E; Auricchio, D; Iori, A; Giannini, F; Rambozzi, L

    2013-02-01

    A study on tick fauna and tick-borne pathogens was undertaken in Pianosa, an island in the Tuscany Archipelago that constitutes an important stopping and nesting point for migratory birds. Ticks were removed from feral cats and a few terrestrial birds, and host-seeking ticks were collected by dragging. A total of 89 ticks were found on animals: 57 Ixodes ventalloi Gil Collado, 1936 and 32 Ixodes acuminatus Neumann, 1901. Host-seeking ticks were 354 Hyalomma spp. larvae and 18 Hyalomma spp. adults, identified as Hyalomma marginatum C.L. Koch, 1844 (n=11) and 7 Hyalomma detritum Schulze, 1919 (n=7). A sample of adult ticks was subjected to molecular analyses to look for Rickettsia spp. and Borrelia burgdorferi sensu lato (s.l.). Sequence analysis of the 5S-23S intergenic spacer region and OspA gene of B. burgdorferi s.l.-positive samples showed the presence of Borrelia spielmanii (n=3; 3.7%, 95% confidence interval [CI] 0.08-10.4) and Borrelia valaisiana (n=13; 13.6%, 95% CI 7.0-23.0) in Ixodes ticks from cats and terrestrial birds. Ixodes spp. were also infected by Rickettsia helvetica (n=19; 23.4%, 95% CI 14.7-34.2). Finally, we detected Rickettsia aeschlimannii in 3 out of 12 host-seeking Hyalomma spp. adults tested (25%, 95% CI 5.5-57.2). Our study shows the presence of several tick-borne pathogens in Pianosa. Hyalomma spp. and Ixodes ticks other than I. ricinus seem to be involved in their epidemiological cycle, and birds could contribute to the pathogen dispersal along their migration routes. This is the first finding of B. spielmanii in Italy. We hypothesize the involvement of peridomestic rodents or hedgehogs in its maintenance in Pianosa.

  19. Environmental influences on soil CO 2 degassing at Furnas and Fogo volcanoes (São Miguel Island, Azores archipelago)

    Science.gov (United States)

    Viveiros, F.; Ferreira, T.; Cabral Vieira, J.; Silva, C.; Gaspar, J. L.

    2008-11-01

    Since October 2001, four soil CO 2 flux stations were installed in the island of São Miguel (Azores archipelago), at Fogo and Furnas quiescent central volcanoes. These stations perform measurements by the accumulation chamber method and, as the gas flux may be influenced by external variables, the stations are equipped with several meteorological sensors. Multivariate regression analysis applied to the large datasets obtained allowed observing that the meteorological variables may influence the soil CO 2 flux oscillations from 18% to 50.5% at the different monitoring sites. Additionally, it was observed that meteorological variables (mainly soil water content, barometric pressure, wind speed and rainfall) play a different role in the control of the gas flux, depending on the selected monitoring site and may cause significant short-term (spike-like) fluctuations. These divergences may be potentially explained by the porosity and hydraulic conductivity of the soils, topographic effects, drainage area and different exposure of the monitoring sites to the weather conditions. Seasonal effects are responsible for long-term oscillations on the gas flux. Before a reliable application of soil CO 2 flux to seismic and/or volcanic monitoring, it is important to recognize those environmental influences on the gas flux. In addition, understanding the external meteorological influences on the gas flux may be important for the public health risk assessment, since meteorological parameters may cause also significant indoor CO 2 increases. In a house at Furnas Village (in Furnas volcano caldera), the values detected reached percentages as high as 20.8% due to significant decreases in the barometric pressure.

  20. Aerobic endospore-forming bacteria from geothermal environments in northern Victoria Land, Antarctica, and Candlemas Island, South Sandwich archipelago, with the proposal of Bacillus fumarioli sp. nov.

    Science.gov (United States)

    Logan, N A; Lebbe, L; Hoste, B; Goris, J; Forsyth, G; Heyndrickx, M; Murray, B L; Syme, N; Wynn-Williams, D D; De Vos, P

    2000-09-01

    Aerobic endospore-forming bacteria were isolated from soils taken from active fumaroles on Mount Rittmann and Mount Melbourne in northern Victoria Land, Antarctica, and from active and inactive fumaroles on Candlemas Island, South Sandwich archipelago. The Mt Rittmann and Mt Melbourne soils yielded a dominant, moderately thermophilic and acidophilic, aerobic endospore-former growing at pH 5.5 and 50 degrees C, and further strains of the same organism were isolated from a cold, dead fumarole at Clinker Gulch, Candlemas Island. Amplified rDNA restriction analysis, SDS-PAGE and routine phenotypic tests show that the Candlemas Island isolates are not distinguishable from the Mt Rittmann strains, although the two sites are 5600 km apart, and 16S rDNA sequence comparisons and DNA relatedness data support the proposal of a new species, Bacillus fumarioli, the type strain of which is LMG 17489T.

  1. Ciguatera risk management in French Polynesia: the case study of Raivavae Island (Australes Archipelago).

    Science.gov (United States)

    Chinain, Mireille; Darius, H Taiana; Ung, André; Fouc, Mote Tchou; Revel, Taina; Cruchet, Philippe; Pauillac, Serge; Laurent, Dominique

    2010-10-01

    Based on epidemiological data available through long-term monitoring surveys conducted by both the Public Health Directorate and the Louis Malardé Institute, ciguatera is highly endemic in French Polynesia, most notably in Raivavae (Australes) which appears as a hot spot of ciguatera with an average incidence rate of 140 cases/10,000 population for the period 2007-2008. In order to document the ciguatera risk associated with Raivavae lagoon, algal and toxin-based field monitoring programs were conducted in this island from April 2007 to May 2008. Practically, the distribution, abundance and toxicity of Gambierdiscus populations, along with the toxicity levels in 160 fish distributed within 25 distinct species, were assessed in various sampling locations. Herbivores such as Scarids (parrotfish) and Acanthurids (unicornfish) were rated as high-risk species based on receptor-binding assay toxicity data. A map of the risk stratification within the Raivavae lagoon was also produced, which indicates that locations where both natural and man-made disturbances have occurred remained the most susceptible to CFP incidents. Our findings also suggest that, locally, the traditional knowledge about ciguatera may not be scientifically complete but is functionally correct. Community education resulted in self-regulating behaviour towards avoidance of high-risk fish species and fishing locations.

  2. A LA-ICP-MS study of minerals in the Rocche Rosse magmatic enclaves: Evidence of a mafic input triggering the latest silicic eruption of Lipari Island (Aeolian Arc, Italy)

    Science.gov (United States)

    Davì, Marcella; De Rosa, Rosanna; Barca, Donatella

    2009-05-01

    The volcanic products of Lipari Island (Aeolian Arc, Italy) younger than 10 ka are mostly aphyric rhyolitic pumices and obsidians emitted during unusual strombolian-type eruptions, which ended with the emplacement of lava flows. The last volcanic activity on the island dates back to 1230 ± 40 AD, with the extrusion of Rocche Rosse (RR) obsidian lava flow. Recently, mafic enclaves of latitic to trachytic composition have been identified and an evolution process between these enclaves and the rhyolitic magma has been documented in detail [Davì, M., 2007. The Rocche Rosse rhyolitic lava flow (Lipari, Aeolian Islands): magmatological and volcanological aspects. Plinius, supplement to the European Journal of Mineralogy 33, 1-8]. In this work textural and trace-element investigation of mineral phases of the RR enclaves, such as crystals of clinopyroxene, olivine, plagioclase, alkali-feldspar and biotite, was carried out to delineate the most recent feeding system of the island, since such a reconstruction could be significant in terms of hazard forecasting. The results indicate that most of the mineral phases are reversely or oscillatory zoned with respect to both major and trace elements, suggesting an early crystallization under low fO 2 conditions from melts of intermediate composition, followed by a later growth from a more mafic (presumably shoshonitic-basaltic) magma than that from which their cores crystallized. Crystals of magnesium-rich pyroxene and forsteritic-rich olivine are indicative of the presence of this shoshonitic basaltic magma. Based on microanalytical data, it is suggested here that the feeding system of recent Lipari volcanic activity was characterized by a shoshonitic-basaltic magma originating from a deep reservoir, which may have evolved and stopped in the crust, generating zoned magma chambers at different depths, in which latitic and rhyolitic magmas reside. The sudden arrival of a new input of mafic melt may have interacted with these

  3. A model to assess fundamental and realized carrying capacities of island ecosystem: A case study in the southern Miaodao Archipelago of China

    Institute of Scientific and Technical Information of China (English)

    SHI Honghua; SHEN Chengcheng; ZHENG Wei; LI Fen; WANG Xiaoli; CHI Yuan; GUO Zhen

    2016-01-01

    Research on carrying capacity, aiming at maintaining the limited ability of the Earth's life supporting system to sustain human development, requires a comprehensive and ecosystem-based approach to monitor and assess the localized sustainability of coupled social and ecological systems. A definition termed the ecosystem-based carrying capacity of island (EBCCI) was developed in this paper of which the indices of fundamental and realized carrying capacities of island (FCCI and RCCI) were highlighted to emphasize the inter-dependencies between social systems and ecological systems. In order to avoid the difficulties and uncertainties of direct assessment, the related assessment model was established on the basis of synthetic evaluation of inherent and external factors affecting the EBCCI. The southern Miaodao Archipelago (SMA) located in the intersection of the Bohai Sea and the Yellow Sea, China, was taken as a typical example to acquire integrated recognition of the island ecosystem and its carrying capacity so as to discuss its sustainable development. The index scores of FCCI and RCCI in the SMA were 0.818 5 and 0.712 9 out of 1.0, respectively, with acceptable uncertainties. The results showed a relatively well capacity to sustain progress and relatively well realization of the carrying capacity of island ecosystem, owing to a well capacity of ecologically regulating, general performance of both ecologically supporting and resource provisioning, and a relatively high level of social supporting system. The study implied that it was critical to optimize the inter-dependencies and to sustain the relative balance between social systems and ecological systems so as to improve the RCCI and further facilitate the sustainability of SMA. The approach proposed in this paper provides a powerful tool which is well applicative to the regional level of an oceanic island or archipelago to study the sustainable development and can be further popularized to the coastal zone.

  4. Soil CO2 degassing path along volcano-tectonic structures in the Pico-Faial-São Jorge islands (Azores archipelago, Portugal)

    Science.gov (United States)

    Viveiros, Fátima; Marcos, Márcio; Faria, Carlos; Gaspar, João L.; Ferreira, Teresa; Silva, Catarina

    2017-06-01

    The Azores archipelago is composed of nine volcanic islands located at the triple junction between the North American, Eurasian and Nubian plates. Nowadays the volcanic activity in the archipelago is characterized by the presence of secondary manifestations of volcanism, such as hydrothermal fumaroles, thermal and cold CO2-rich springs as well as soil diffuse degassing areas, and low magnitude seismicity. Soil CO2 degassing (concentration and flux) surveys have been performed at Pico, Faial and São Jorge islands to identify possible diffuse degassing structures. Since the settlement of the Azores in the 15th Century these three islands were affected by seven onshore volcanic eruptions and at least six destructive earthquakes. These islands are crossed by numerous active tectonic structures with dominant WNW-ESE direction, and less abundant conjugate NNW-SSE trending faults. A total of 2855 soil CO2 concentration measurements have been carried out with values varying from 0 to 20.7 vol.%. Soil CO2 flux measurements, using the accumulation chamber method, have also been performed at Pico and Faial islands in the summer of 2011 and values varied from absence of CO2 to 339 g m-2 d-1. The highest CO2 emissions were recorded at Faial Island and were associated with the Pedro Miguel graben faults, which seem to control the CO2 diffuse degassing and were interpreted as the pathways for the CO2 ascending from deep reservoirs to the surface. At São Jorge Island, four main degassing zones have been identified at the intersection of faults or associated to WNW-ESE tectonic structures. Four diffuse degassing structures were identified at Pico Island essentially where different faults intersect. Pico geomorphology is dominated by a 2351 m high central volcano that presents several steam emissions at its summit. These emissions are located along a NW-SE fault and the highest measured soil CO2 concentration reached 7.6 vol.% with a maximum temperature of 77 ºC. The diffuse

  5. Soil CO2 Degassing Path along Volcano-Tectonic Structures in the Pico-Faial-São Jorge Islands (Azores Archipelago, Portugal

    Directory of Open Access Journals (Sweden)

    Fátima Viveiros

    2017-06-01

    Full Text Available The Azores archipelago is composed of nine volcanic islands located at the triple junction between the North American, Eurasian, and Nubian plates. Nowadays the volcanic activity in the archipelago is characterized by the presence of secondary manifestations of volcanism, such as hydrothermal fumaroles, thermal and cold CO2-rich springs as well as soil diffuse degassing areas, and low magnitude seismicity. Soil CO2 degassing (concentration and flux surveys have been performed at Pico, Faial, and São Jorge islands to identify possible diffuse degassing structures. Since the settlement of the Azores in the fifteenth Century these three islands were affected by seven onshore volcanic eruptions and at least six destructive earthquakes. These islands are crossed by numerous active tectonic structures with dominant WNW-ESE direction, and less abundant conjugate NNW-SSE trending faults. A total of 2,855 soil CO2 concentration measurements have been carried out with values varying from 0 to 20.7 vol.%. Soil CO2 flux measurements, using the accumulation chamber method, have also been performed at Pico and Faial islands in the summer of 2011 and values varied from absence of CO2 to 339 g m−2 d−1. The highest CO2 emissions were recorded at Faial Island and were associated with the Pedro Miguel graben faults, which seem to control the CO2 diffuse degassing and were interpreted as the pathways for the CO2 ascending from deep reservoirs to the surface. At São Jorge Island, four main degassing zones have been identified at the intersection of faults or associated to WNW-ESE tectonic structures. Four diffuse degassing structures were identified at Pico Island essentially where different faults intersect. Pico geomorphology is dominated by a 2,351 m high central volcano that presents several steam emissions at its summit. These emissions are located along a NW-SE fault and the highest measured soil CO2 concentration reached 7.6 vol.% with a maximum

  6. Formation of cordierite-bearing lavas during anatexis in the lower crust beneath Lipari Island (Aeolian arc, Italy)

    Science.gov (United States)

    di Martino, Corrado; Forni, Francesca; Frezzotti, Maria Luce; Palmeri, Rosaria; Webster, James D.; Ayuso, Robert A.; Lucchi, Federico; Tranne, Claudio A.

    2011-11-01

    Cordierite-bearing lavas (CBL;~105 ka) erupted from the Mt. S. Angelo volcano at Lipari (Aeolian arc, Italy) are high-K andesites, displaying a range in the geochemical and isotopic compositions that reflect heterogeneity in the source and/or processes. CBL consist of megacrysts of Ca-plagioclase and clinopyroxene, euhedral crystals of cordierite and garnet, microphenocrysts of orthopyroxene and plagioclase, set in a heterogeneous rhyodacitic-rhyolitic groundmass containing abundant metamorphic and gabbroic xenoliths. New petrographic, chemical and isotopic data indicate formation of CBL by mixing of basaltic-andesitic magmas and high-K peraluminous rhyolitic magmas of anatectic origin and characterize partial melting processes in the lower continental crust of Lipari. Crustal anatectic melts generated through two main dehydration-melting peritectic reactions of metasedimentary rocks: (1) Biotite + Aluminosilicate + Quartz + Albite = Garnet + Cordierite + K-feldspar + Melt; (2) Biotite + Garnet + Quartz = Orthopyroxene + Cordierite + K-feldspar + Melt. Their position into the petrogenetic grid suggests that heating and consequent melting of metasedimentary rocks occurred at temperatures of 725 Lipari was induced by protracted emplacement of basic magmas in the lower crust (~130 Ky). Crustal melting of the lower crust at 105 ka affected the volcano evolution, impeding frequent mafic-magma eruptions, and promoting magma stagnation and fractional crystallization processes.

  7. Formation of cordierite-bearing lavas during anatexis in the lower crust beneath Lipari Island (Aeolian arc, Italy)

    Science.gov (United States)

    Di, Martino C.; Forni, F.; Frezzotti, M.L.; Palmeri, R.; Webster, J.D.; Ayuso, R.A.; Lucchi, F.; Tranne, C.A.

    2011-01-01

    Cordierite-bearing lavas (CBL;~105 ka) erupted from the Mt. S. Angelo volcano at Lipari (Aeolian arc, Italy) are high-K andesites, displaying a range in the geochemical and isotopic compositions that reflect heterogeneity in the source and/or processes. CBL consist of megacrysts of Ca-plagioclase and clinopyroxene, euhedral crystals of cordierite and garnet, microphenocrysts of orthopyroxene and plagioclase, set in a heterogeneous rhyodacitic-rhyolitic groundmass containing abundant metamorphic and gabbroic xenoliths. New petrographic, chemical and isotopic data indicate formation of CBL by mixing of basaltic-andesitic magmas and high-K peraluminous rhyolitic magmas of anatectic origin and characterize partial melting processes in the lower continental crust of Lipari. Crustal anatectic melts generated through two main dehydration-melting peritectic reactions of metasedimentary rocks: (1) Biotite + Aluminosilicate + Quartz + Albite = Garnet + Cordierite + K-feldspar + Melt; (2) Biotite + Garnet + Quartz = Orthopyroxene + Cordierite + K-feldspar + Melt. Their position into the petrogenetic grid suggests that heating and consequent melting of metasedimentary rocks occurred at temperatures of 725 crust of Lipari was induced by protracted emplacement of basic magmas in the lower crust (~130 Ky). Crustal melting of the lower crust at 105 ka affected the volcano evolution, impeding frequent maficmagma eruptions, and promoting magma stagnation and fractional crystallization processes. ?? 2011 Springer-Verlag.

  8. Dragons in the mist: three new species of Pseudocalotes Fitzinger (Squamata: Agamidae) from the sky island archipelago of Peninsular Malaysia.

    Science.gov (United States)

    Grismer, L Lee; Quah, Evan S H; Wood, Perry L Jr; Anuar, Shahrul; Muin, Abdul; Davis, Hayden R; Murdoch, Matthew L; Grismer, Jesse L; Cota, Michael; Cobos, Anthony J

    2016-07-07

    An integrative taxonomic analysis is used to delimit and describe three new species of Pseudocalotoes from the sky island archipelago of the Banjaran (=mountain range) Titiwangsa of Peninsular Malaysia. Pseudocalotes drogon sp. nov., from Fraser's Hill, Pahang is basal to the sister species P. larutensis from Bukit Larut, Perak in the Banjaran Bintang and the new species P. rhaegal sp. nov. from Cameron Highlands, Pahang. Pseudocalotes drogon sp. nov. is differentiated from all other species of Psuedocalotes by having the combination of a flat rostrum; seven postrostrals; an interparietal; 11 circumorbitals; five canthals; 7-10 superciliaries; one scale between the rostral and nasal; nine supralabials; eight infralabials; 10 postnasal-suborbital scales; four postmentals; five or six sublabials; five or six chinshields; 47 smooth, wide, gular scales; weak transverse gular and antehumeral folds; two enlarged scales between the ear and eye; enlarged upper and lower posttemporals; a single enlarged supratympanic; no enlarged postrictals; three large scales bordering the dorsal margin of the ear opening; large pretympanic scales; eight scales in the nuchal crest not separated by a gap; enlarged vertebral scales extending to the tip of the tail; keeled and non-plate-like scales on flanks; 51 midbody scales; midventrals smaller than dorsals; 19 subdigital lamellae on the fourth finger; 23 subdigital lamellae on the fourth toe; preaxial scales on third toe enlarged and spinose; subdigital lamellae not unicarinate; HW/HL 0.52; HL/SVL 0.31; no elbow or knee patches; and a male dewlap color of lime-green bearing a central yellow spot. Pseudocalotes rhaegal sp. nov. is differentiated from all other Psuedocalotes by having the combination of a convex rostrum; 6-8 postrostrals; an interparietal; nine or 10 circumorbitals; five canthals; 7-10 superciliaries; one or two scales between the rostral and nasal scales; eight or nine supralabials; seven or eight infralabials; 11 or 12

  9. Reefs and islands of the Chagos Archipelago, Indian Ocean: why it is the world’s largest no-take marine protected area

    Science.gov (United States)

    SHEPPARD, C. R. C.; ATEWEBERHAN, M.; BOWEN, B. W.; CARR, P.; CHEN, C. A.; CLUBBE, C.; CRAIG, M. T.; EBINGHAUS, R.; EBLE, J.; FITZSIMMONS, N.; GAITHER, M. R.; GAN, C-H.; GOLLOCK, M.; GUZMAN, N.; GRAHAM, N. A. J.; HARRIS, A.; JONES, R.; KESHAVMURTHY, S.; KOLDEWEY, H.; LUNDIN, C. G.; MORTIMER, J. A.; OBURA, D.; PFEIFFER, M.; PRICE, A. R. G.; PURKIS, S.; RAINES, P.; READMAN, J. W.; RIEGL, B.; ROGERS, A.; SCHLEYER, M.; SEAWARD, M. R. D; SHEPPARD, A. L. S.; TAMELANDER, J.; TURNER, J. R.; VISRAM, S.; VOGLER, C.; VOGT, S.; WOLSCHKE, H.; YANG, J. M-C.; YANG, S-Y.; YESSON, C.

    2014-01-01

    The Chagos Archipelago was designated a no-take marine protected area (MPA) in 2010; it covers 550 000 km2, with more than 60 000 km2 shallow limestone platform and reefs. This has doubled the global cover of such MPAs.It contains 25–50% of the Indian Ocean reef area remaining in excellent condition, as well as the world’s largest contiguous undamaged reef area. It has suffered from warming episodes, but after the most severe mortality event of 1998, coral cover was restored after 10 years.Coral reef fishes are orders of magnitude more abundant than in other Indian Ocean locations, regardless of whether the latter are fished or protected.Coral diseases are extremely low, and no invasive marine species are known.Genetically, Chagos marine species are part of the Western Indian Ocean, and Chagos serves as a ‘stepping-stone’ in the ocean.The no-take MPA extends to the 200 nm boundary, and. includes 86 unfished seamounts and 243 deep knolls as well as encompassing important pelagic species.On the larger islands, native plants, coconut crabs, bird and turtle colonies were largely destroyed in plantation times, but several smaller islands are in relatively undamaged state.There are now 10 ‘important bird areas’, coconut crab density is high and numbers of green and hawksbill turtles are recovering.Diego Garcia atoll contains a military facility; this atoll contains one Ramsar site and several ‘strict nature reserves’. Pollutant monitoring shows it to be the least polluted inhabited atoll in the world. Today, strict environmental regulations are enforced.Shoreline erosion is significant in many places. Its economic cost in the inhabited part of Diego Garcia is very high, but all islands are vulnerable.Chagos is ideally situated for several monitoring programmes, and use is increasingly being made of the archipelago for this purpose. PMID:25505830

  10. Evidence of stable genetic structure across a remote island archipelago through self-recruitment in a widely dispersed coral reef fish

    KAUST Repository

    Priest, Mark

    2012-11-19

    We used microsatellite markers to assess the population genetic structure of the scribbled rabbitfish Siganus spinus in the western Pacific. This species is a culturally important food fish in the Mariana Archipelago and subject to high fishing pressure. Our primary hypothesis was to test whether the individuals resident in the southern Mariana Island chain were genetically distinct and hence should be managed as discrete stocks. In addition to spatial sampling of adults, newly-settled individuals were sampled on Guam over four recruitment events to assess the temporal stability of the observed spatial patterns, and evidence of self-recruitment. We found significant genetic structure in S. spinus across the western Pacific, with Bayesian analyses revealing three genetically distinct clusters: the southernMariana Islands, east Micronesia, and the west Pacific; with the southern Mariana Islands beingmore strongly differentiated fromthe rest of the region. Analyses of temporal samples from Guam indicated the southern Mariana cluster was stable over time, with no genetic differentiation between adults versus recruits, or between samples collected across four separate recruitment events spanning 11 months. Subsequent assignment tests indicated seven recruits had self-recruited from within the Southern Mariana Islands population. Our results confirm the relative isolation of the southern Mariana Islands population and highlight how local processes can act to isolate populations that, by virtue of their broad-scale distribution, have been subject to traditionally high gene flows. Our results add to a growing consensus that self-recruitment is a highly significant influence on the population dynamics of tropical reef fish. 2012 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.

  11. Evidence of stable genetic structure across a remote island archipelago through self-recruitment in a widely dispersed coral reef fish.

    Science.gov (United States)

    Priest, Mark A; Halford, Andrew R; McIlwain, Jennifer L

    2012-12-01

    We used microsatellite markers to assess the population genetic structure of the scribbled rabbitfish Siganus spinus in the western Pacific. This species is a culturally important food fish in the Mariana Archipelago and subject to high fishing pressure. Our primary hypothesis was to test whether the individuals resident in the southern Mariana Island chain were genetically distinct and hence should be managed as discrete stocks. In addition to spatial sampling of adults, newly-settled individuals were sampled on Guam over four recruitment events to assess the temporal stability of the observed spatial patterns, and evidence of self-recruitment. We found significant genetic structure in S. spinus across the western Pacific, with Bayesian analyses revealing three genetically distinct clusters: the southern Mariana Islands, east Micronesia, and the west Pacific; with the southern Mariana Islands being more strongly differentiated from the rest of the region. Analyses of temporal samples from Guam indicated the southern Mariana cluster was stable over time, with no genetic differentiation between adults versus recruits, or between samples collected across four separate recruitment events spanning 11 months. Subsequent assignment tests indicated seven recruits had self-recruited from within the Southern Mariana Islands population. Our results confirm the relative isolation of the southern Mariana Islands population and highlight how local processes can act to isolate populations that, by virtue of their broad-scale distribution, have been subject to traditionally high gene flows. Our results add to a growing consensus that self-recruitment is a highly significant influence on the population dynamics of tropical reef fish.

  12. High resolution seismic data coupled to Multibeam bathymetry of Stromboli island collected in the frame of the Stromboli geophysical experiment: implications with the marine geophysics and volcanology of the Aeolian Arc volcanic complex (Sicily, Southern Tyrrhenian sea, Italy).

    Science.gov (United States)

    Aiello, Gemma; Di Fiore, Vincenzo; Marsella, Ennio; Passaro, Salvatore

    2014-01-01

    New high resolution seismic data (Subbottom Chirp) coupled to high resolution Multibeam bathymetry collected in the frame of the Stromboli geophysical experiment aimed at recording active seismic data and tomography of the Stromboli Island are here presented. The Stromboli geophysical experiment has been already carried out based on onshore and offshore data acquisition in order to investigate the deep structure and the location of the magma chambers of the Stromboli volcano. A new detailed swath bathymetry of Stromboli Island is here shown and discussed to reconstruct an up-to-date morpho-bathymetry and marine geology of the area compared to the volcanologic setting of the Aeolian Arc volcanic complex. Due to its high resolution the new Digital Terrain Model of the Stromboli Island gives interesting information about the submerged structure of the volcano, particularly about the volcano-tectonic and gravitational processes involving the submarine flanks of the edifice. Several seismic units have been identified based on the geologic interpretation of Subbottom Chirp profiles recorded around the volcanic edifice and interpreted as volcanic acoustic basement pertaining to the volcano and overlying slide chaotic bodies emplaced during its complex volcano-tectonic evolution. They are related to the eruptive activity of Stromboli, mainly poliphasic and to regional geological processes involving the intriguing geology of the Aeolian Arc, a volcanic area still in activity and needing improved research interest.

  13. Marine-continental tephra correlations: Volcanic glass geochemistry from the Marsili Basin and the Aeolian Islands, Southern Tyrrhenian Sea, Italy

    Science.gov (United States)

    Albert, P. G.; Tomlinson, E. L.; Smith, V. C.; Di Roberto, A.; Todman, A.; Rosi, M.; Marani, M.; Muller, W.; Menzies, M. A.

    2012-06-01

    Major, minor and trace element analysis of volcanic glass in proximal and distal (Lipari (Monte Pilato; 776 cal AD); (2) Vulcano; and (3) Campi Flegrei (Soccavo 1; 11,915-12,721 cal years BP). Whether a polymictic coarse grained volcaniclastic turbidite in the Marsili Basin originated from collapse on Salina remains unresolved because multi-elemental analysis raises doubt about the published correlation to the Pollara region. It is evident that correlation of proximal continental and distal marine tephras, at a high level of confidence, requires a full complement of major, minor and trace element data. In conjunction with considerations of the mineralogy and morphology of juvenile deposits these data help define petrological lineages such that precise provenance can be established. Whilst a precise proximal-distal match must be based on identical major, minor and trace element concentrations it is clear that resurgent activity from a single volcano can produce magmas with identical compositions. In such cases stratigraphic relationships must complement any geochemical study. Occasionally proximal stratigraphies may be unrepresentative of the complete eruptive history because of a lack of exposure due to burial by more recent effusive and explosive activity, or sector collapse which can remove vital stratigraphy particularly on volcanic islands.

  14. Contrasting sediment melt and fluid signatures for magma components in the Aeolian Arc: Implications for numerical modeling of subduction systems

    Science.gov (United States)

    Zamboni, Denis; Gazel, Esteban; Ryan, Jeffrey G.; Cannatelli, Claudia; Lucchi, Federico; Atlas, Zachary D.; Trela, Jarek; Mazza, Sarah E.; De Vivo, Benedetto

    2016-06-01

    The complex geodynamic evolution of Aeolian Arc in the southern Tyrrhenian Sea resulted in melts with some of the most pronounced along the arc geochemical variation in incompatible trace elements and radiogenic isotopes worldwide, likely reflecting variations in arc magma source components. Here we elucidate the effects of subducted components on magma sources along different sections of the Aeolian Arc by evaluating systematics of elements depleted in the upper mantle but enriched in the subducting slab, focusing on a new set of B, Be, As, and Li measurements. Based on our new results, we suggest that both hydrous fluids and silicate melts were involved in element transport from the subducting slab to the mantle wedge. Hydrous fluids strongly influence the chemical composition of lavas in the central arc (Salina) while a melt component from subducted sediments probably plays a key role in metasomatic reactions in the mantle wedge below the peripheral islands (Stromboli). We also noted similarities in subducting components between the Aeolian Archipelago, the Phlegrean Fields, and other volcanic arcs/arc segments around the world (e.g., Sunda, Cascades, Mexican Volcanic Belt). We suggest that the presence of melt components in all these locations resulted from an increase in the mantle wedge temperature by inflow of hot asthenospheric material from tears/windows in the slab or from around the edges of the sinking slab.

  15. New record of sheep frog (Hypopachus variolosus) in the Tres Marías Islands archipelago, Nayarit, Mexico Nuevo registro de la rana ovejera (Hypopachus variolosus) en el archipiélago de las islas Marías, Nayarit, México

    OpenAIRE

    J. Antonio de la Torre; Leonardo J. López-Damián; Horacio V. Bárcenas; Edith Nájera-Solís; Rodrigo A Medellín

    2010-01-01

    During a recent visit to María Madre Island, in the Tres Marías Island archipelago, 2 specimens of Hypopachus variolosus were found. This new record of the sheep frog from Tres Marías Island archipelago represents the first island record for this species. Due to the uncertainty about its conservation status in this locality, we consider necessary to improve the information about this species in the island.Durante una reciente vista a la isla María Madre del archipiélago de las islas Marías se...

  16. Soil-geomorphology interactions and paleoclimatic implications of an ornithogenic soil toposequence on Rata Island, Fernando de Noronha Archipelago, South Atlantic

    Science.gov (United States)

    de Oliveira, Fábio Soares; Schaefer, Carlos Ernesto G. R.; Abrahão, Walter Antônio Pereira; Clemente, Eliane de Paula; Simas, Felipe Nogueira Bello

    2014-07-01

    The formation of highly phosphatized soils on sites of avian activity is a common feature of oceanic islands. We characterized a toposequence of phosphatic soils on Rata Island, to evaluate the soil genesis based on local topographic variations. For this purpose, four soils ranging from the upper hill down to the lowest landscape position on the island, representing a range of parent materials (basalt and calcareous sands), were analyzed. In the lowest landscape position a shallow Regosol was identified, strongly influenced by birds and marine sprays, developed on “karstified” Pleistocene calcarenites; the three other soils in the upper part of the toposequence are Ornithogenic Cambisols, ranging from a deep Cambisol profile on Basalt lava to intermediate Cambisols on mixed colluvial sediments of the basalt/calcareous. The lowermost Regosol is associated with a rugged landscape with strong calcarenite dissolution and karstification. The soil phosphatization is clearly an inherited process of the Late Quaternary age, when climate conditions were different. Initial weathering took place in the last interglacial period, under wetter conditions during which the Tertiary basalts were strongly weathered, leaving corestones in a saprolitic, oxidized mass. In the late Pleistocene, a gentle surface distributed these weathering products along the pediment slopes as colluvial materials, whereas in the coastal areas aeolian processes formed large sand dunes composed of reworked calcareous sands from marine sources during a time of very low sea level. During this time, widespread bird activity accounted for secondary apatite formation on the surface of calcareous oolites. Finally, the Holocene warming was accompanied by increasing sea level, enhanced tropical weathering, Fe and Al mobility and variscite formation superimposed on degraded Ca-phosphates, forming two phase phosphatic aggregates.

  17. Taxonomy and zoogeography of Dobsonia Palmer, 1898, from the Louisiade Archipelago, the D’Entrecasteaux Group, Trobriand Island and Woodlark Island (Mammalia, Megachiroptera)

    NARCIS (Netherlands)

    Bergmans, Wim

    1979-01-01

    A lectotype is selected — and its skull figured, for the first time — for Dobsonia pannietensis (De Vis, 1905), which is considered to be a good species. Specimens have been examined from the Louisiades, the D’Entrecasteaux Group, Trobriand Island and Woodlark Island. The species varies per island o

  18. Thinking in Islands; The Portuguese perception of the Indonesian archipelago and particularly of Sunda in early texts and charts

    Directory of Open Access Journals (Sweden)

    Svann Langguth

    2012-10-01

    Full Text Available This article discusses various early sources on the Indonesian archipelago. It starts with the status of knowledge before the first voyage of the Portuguese to the Moluccas from accounts of travellers to insular Southeast Asia in the Middle Ages and the picture on world maps European cartographers produced. Comparing that view with text sources and the resulting geographic material of the first expeditions by the Portuguese provides an insight into contemporary mechanisms of knowledge transfer. Certain effects can be traced and are repeated on different levels of access to the original facts mainly because most maps were drawn up in Europe but based on the geographic description provided by text accounts. An abundance and multiplication of failures and mistakes is evident and is partly related to the scarcity of sources and due to reproduction techniques.

  19. Insights from geophysical monitoring into the volcano structure and magma supply systems at three very different oceanic islands in the Cape Verde archipelago

    Science.gov (United States)

    Faria, B. V.; Day, S.; Fonseca, J. F.

    2013-12-01

    Three oceanic volcano islands in the west of the Cape Verde archipelago are considered to have the highest levels of volcanic hazard in the archipelago: Fogo, Brava, and Santo Antao. Fogo has had frequent mainly effusive eruptions in historic time, the most recent in 1995, whilst Brava and Santo Antao have ongoing geothermal activity and felt earthquakes, and have experienced geologically recent violent explosive eruptions. Therefore, these three islands have been the focus of recent efforts to set up seismic networks to monitor their activity. Here we present the first results from these networks, and propose interpretations of the monitored seismic activity in terms of subsurface volcano structures, near-surface intrusive activity and seasonal controls on geothermal activity. In Fogo, most recorded seismic events are hydrothermal events. These show a strong seasonal variation, increasing during the summer rain season and decreasing afterwards. Rare volcano-tectonic (VT) events (0.1scar. They are interpreted as shear failures between unconsolidated material at the base of the collapse scar fill and underlying more rigid pre-collapse rocks with abundant dikes, occuring as a result of long-term gravitational re-adjustment of the collapse scar fill after inflation of the island due to the 1995 eruption. Brava experiences frequent swarms of VT events. These are located mostly offshore, with a small proportion of on-shore events. The positions of offshore events are strongly correlated with seamounts and hence are interpreted as due to submarine volcanic processes. Onshore events (0.7island that has been indicated by previous geological studies, and may be due to inflation of a magma reservoir in the edifice. S. Antão is characterized by frequent seismic swarms composed of VT earthquakes (0.1

  20. Molecular detection of Anaplasma platys, Ehrlichia canis, Hepatozoon canis and Rickettsia monacensis in dogs from Maio Island of Cape Verde archipelago.

    Science.gov (United States)

    Lauzi, Stefania; Maia, João P; Epis, Sara; Marcos, Ricardo; Pereira, Cristina; Luzzago, Camilla; Santos, Marta; Puente-Payo, Pablo; Giordano, Alessia; Pajoro, Massimo; Sironi, Giuseppe; Faustino, Augusto

    2016-07-01

    Tick-borne diseases are emerging worldwide and have an important zoonotic relevance. Dogs play an important role in the epidemiology of several zoonotic tick-borne pathogens acting as sentinels and/or reservoirs. This study focused on the molecular identification of tick-borne pathogens in blood samples of 153 autochthonous asymptomatic dogs in Maio Island, Cape Verde archipelago. Eighty-four (54.9%) dogs were positive for one or more pathogens. Fifty-five (35.9%) dogs were infected with Hepatozoon canis, 53 (34.6%) with Anaplasma platys, five (3.3%) with Ehrlichia canis and Rickettsia monacensis, an emerging human pathogen, was also identified in a single dog (0.7%). The former three pathogens cause important canine tick-borne diseases that are transmitted or potentially transmitted by Rhipicephalus sanguineus s.l., the only hard tick identified in Cape Verde. Furthermore, Wolbachia spp. was amplified from the blood of one dog. None of the dogs were positive for Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Midichloria mitochondrii, Bartonella spp., Babesia spp. or Theileria spp. Fifty-four (35.3%) animals showed single infections and 30 (19.6%) co-infections, with A. platys and H. canis co-infection being the most frequent (28 dogs, 18.3%). The frequency of E. canis infection was statistically different among age groups (P=0.017), being higher among dogs older than 4 years compared to younger dogs. Infection by A. platys was also statistically different among age groups (P=0.031), being higher in dogs younger than 2 years compared to older dogs. The statistical analyses showed no significant association of PCR positivity with gender or location. The frequency of tick-borne pathogens detected in dogs in Maio Island, including R. monacensis, highlights the need to improve diagnosis and control in order to prevent the risk of transmission of these pathogens among dogs and humans living in or travelling to this touristic island.

  1. Paleomagnetism from Deception Island (South Shetlands archipelago, Antarctica), new insights into the interpretation of the volcanic evolution using a geomagnetic model

    Science.gov (United States)

    Oliva-Urcia, B.; Gil-Peña, I.; Maestro, A.; López-Martínez, J.; Galindo-Zaldívar, J.; Soto, R.; Gil-Imaz, A.; Rey, J.; Pueyo, O.

    2016-07-01

    Deception Island shows the most recent exposed active volcanism in the northern boundary of the Bransfield Trough. The succession of the volcanic sequence in the island is broadly divided into pre- and post-caldera collapse units although a well-constrained chronological identification of the well-defined successive volcanic episodes is still needed. A new paleomagnetic investigation was carried out on 157 samples grouped in 20 sites from the volcanic deposits of Deception Island (South Shetlands archipelago, Antarctic Peninsula region) distributed in: (1) volcanic breccia (3 sites) and lavas (2 sites) prior to the caldera collapse; (2) lavas emplaced after the caldera collapse (10 sites); and (3) dikes cutting pre- and the lowermost post-caldera collapse units (5 sites). The information revealed by paleomagnetism provides new data about the evolution of the multi-episodic volcanic edifice of this Quaternary volcano, suggesting that the present-day position of the volcanic materials is close to their original emplacement position. The new data have been combined with previous paleomagnetic results in order to tentatively propose an age when comparing the paleomagnetic data with a global geomagnetic model. Despite the uncertainties in the use of averaged paleomagnetic data per volcanic units, the new data in combination with tephra occurrences noted elsewhere in the region suggest that the pre-caldera units (F1 and F2) erupted before 12,000 year BC, the caldera collapse took place at about 8300 year BC, and post-caldera units S1 and S2 are younger than 2000 year BC.

  2. Distribution and diversity of marine flora in coral reef ecosystems of Kadmat Island in Lakshadweep archipelago, Arabian Sea, India

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, V.V.; Komarpant, D.S.; Jagtap, T.G.

    is under constant threat of reclamation for cultivation of vegetables and dwellings. Poor composition, particularly of corals, indicated that the reefs around Kadmat Island were converting into algal or detrital reefs...

  3. Archipelago-Wide Island Restoration in the Galápagos Islands: Reducing Costs of Invasive Mammal Eradication Programs and Reinvasion Risk

    OpenAIRE

    Victor Carrion; C. Josh Donlan; Karl J Campbell; Christian Lavoie; Felipe Cruz

    2011-01-01

    Invasive alien mammals are the major driver of biodiversity loss and ecosystem degradation on islands. Over the past three decades, invasive mammal eradication from islands has become one of society's most powerful tools for preventing extinction of insular endemics and restoring insular ecosystems. As practitioners tackle larger islands for restoration, three factors will heavily influence success and outcomes: the degree of local support, the ability to mitigate for non-target impacts, and ...

  4. A new species of extinct scops owl (Aves: Strigiformes: Strigidae: Otus) from São Miguel Island (Azores Archipelago, North Atlantic Ocean).

    Science.gov (United States)

    Rando, Juan Carlos; Alcover, Josep Antoni; Olson, Storrs L; Pieper, Harald

    2013-01-01

    The extinct São Miguel Scops Owl Otusfrutuosoi n. sp. is described from fossil bones found in Gruta de Água de Pau, a volcanic tube in São Miguel Island (Azores Archipelago, North Atlantic Ocean). It is the first extinct bird described from the Azores and, after the Madeiran Scops Owl (O. mauli Rando, Pieper, Alcover & Olson 2012a), the second extinct species of Strigiformes known in Macaronesia. The forelimb elements of the new taxon are shorter, the hindlimb elements are longer, and the pelvis is shorter and broader than in the Eurasian Scops Owl (O. scops Linnaeus). The new species differs from O. mauli in the smaller size of many of its bones, especially the ulna and tibiotarsus. Its measurements (estimated weight, wing area, and wing loading, and the ratio of humerus + ulna + carpometacarpus length/femur length) indicate weak powers of flight and ground-dwelling habits. The latest occurrence of the new species, as evidenced by a radiocarbon date of 1970 ± 40 BP from bone collagen, indicates a Late Holocene extinction event subsequent to 49 cal BC, and was probably linked to human arrival and subsequent habitat alterations.

  5. Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago

    Directory of Open Access Journals (Sweden)

    Zoltan Csiki-Sava

    2015-01-01

    Full Text Available The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over the past two decades, promising new insights into latest Cretaceous faunal evolution. We review the terrestrial Late Cretaceous record from Europe and discuss its importance for understanding the paleogeography, ecology, evolution, and extinction of land-dwelling vertebrates. We review the major Late Cretaceous faunas from Austria, Hungary, France, Spain, Portugal, and Romania, as well as more fragmentary records from elsewhere in Europe. We discuss the paleogeographic background and history of assembly of these faunas, and argue that they are comprised of an endemic ‘core’ supplemented with various immigration waves. These faunas lived on an island archipelago, and we describe how this insular setting led to ecological peculiarities such as low diversity, a preponderance of primitive taxa, and marked changes in morphology (particularly body size dwarfing. We conclude by discussing the importance of the European record in understanding the end-Cretaceous extinction and show that there is no clear evidence that dinosaurs or other groups were undergoing long-term declines in Europe prior to the bolide impact.

  6. Small-scale spatial and temporal reproductive variability of the brown macroalga Sargassum thunbergii in contrasting habitats: A study on the island of Xiaoheishan, Changdao Archipelago, China

    Science.gov (United States)

    Yu, Yongqiang; Zhang, Quansheng; Lu, Zhicheng; Tang, Yongzheng; Zhang, Shubao; Chu, Shaohua

    2012-10-01

    A study of the reproductive pattern of Sargassum thunbergii, which is distributed widely around the island of Xiaoheishan (Changdao Archipelago, China), shows that it exhibits a flexibility to adapt to contrasting habitats. Populations of S. thunbergii from two depths at nine field sites exposed to increasing degrees of wave action were studied to determine their spatio-temporal variations in reproductive pattern. The start of the reproductive period was significantly delayed with increasing geographical latitude but independent of depth and wave exposure, and seawater temperature was found to be a significant controlling factor for maturation. In contrast with reproductive onset, two-way ANCOVA showed that there were significant effects of both depth and wave exposure on the peak and end point of the reproductive period. The latter were significantly delayed in the semi-exposed deep-water habitats compared to sheltered shallow-water habitats. The shortest duration of the reproductive period was recorded in the wave-exposed shallow-water habitats, while the longest duration was in the semi-exposed deep-water habitats. In addition, reproductive allocation (RA) in the studied populations showed a similar and significant temporal variation during reproduction, and RA increased as time progressed, followed by a rapid decrease in late summer. Wave exposure as well as depth also influenced significantly the RA whereby thalli from exposed and semi-exposed deep-water habitats allocated significantly more biomass to the production of receptacles than did thalli from sheltered shallow-water habitats.

  7. Biodiversity and management of the Madrean Archipelago: The Sky Islands of southwestern United States and northwestern Mexico

    Science.gov (United States)

    Leonard H. DeBano; Peter H. Ffolliott; Alfredo Ortega-Rubio; Gerald J. Gottfried; Robert H. Hamre; Carleton B. Edminster

    1995-01-01

    This conference brought together scientists and managers from government, universities, and private organizations to examine the biological diversity and management challenges of the unique "sky island" ecosystems of the mountains of the southwestern United States and northwestern Mexico. Session topics included: floristic resources, plant ecology,...

  8. Impact of commercial fishing on Trindade Island and Martin Vaz Archipelago, Brazil: characteristics, conservation status of the species involved and prospects for preservation

    Directory of Open Access Journals (Sweden)

    Hudson Tercio Pinheiro

    2010-12-01

    Full Text Available Visual records, radio interviews and onboard observations of the fishing activities during a 58 days scientific expedition to Trindade Island and the Martin Vaz Archipelago were obtained from February to April 2007. The regular activities of four different fisheries were observed: pelagic longline, bottom line, trolling and handline. These fisheries caused mortality of at least seven species with some level threat, according to the International Union for Conservation of Nature list. The establishment of specific restriction norms for hook-and-line activities around the oceanic islands was seen as an alternative for the conservation of the ichthyofauna of the region. Satellite monitoring to track the fishery vessels could be established through the national program as another legal mean to diminish fishing the impact.Reportamos atividades de pesca comerciais no complexo insular mais afastado da costa brasileira: Ilha da Trindade e Arquipélago Martin Vaz. As atividades foram estudadas através de embarques e entrevistas com os mestres e pescadores das embarcações durante uma expedição cientifica realizada entre fevereiro e abril de 2007. Quatro modalidades de atividades de pesca são realizadas na região, capturando ao menos sete espécies que possuem algum risco de extinção. O estabelecimento de normas específicas de restrição para atividades que pescam sobre os recifes das ilhas é uma alternativa para a conservação das espécies ameaçadas. O monitoramento das embarcações pode ocorrer via satélite através do programa nacional de rastreamento de embarcações pesqueiras (PREPS.

  9. Genetic differentiation between marine iguanas from different breeding sites on the island of Santa Fe (Galapagos Archipelago).

    Science.gov (United States)

    Lanterbecq, Deborah; Glaberman, Scott; Vitousek, Maren Noelani; Steinfartz, Sebastian; Benavides, Edgar; Wikelski, Martin; Caccone, Adalgisa

    2010-01-01

    We studied patterns of genetic diversity within and among 5 populations (318 individuals) of Galápagos marine iguanas (Amblyrhynchus cristatus) from the island Santa Fé. Populations were separated by distances of 0.2 to 9.9 km. We sequenced 1182 base pairs of the mitochondrial control region and screened 13 microsatellite loci for variability. We also added data from 5 populations (397 individuals) sampled on 4 neighboring islands (Santa Cruz, Floreana, Espanola, and San Cristobal). The 5 Santa Fé populations, revealed as genetically distinct from populations on other islands, present relatively low levels of genetic diversity, which are similar for both microsatellite (average observed heterozygosity from 0.7686 to 0.7773) and mitochondrial DNA (mtDNA) markers (haplotypic and nucleotide diversity from 0.587 to 0.728 and from 0.00079 to 0.00293, respectively), and comparable with those observed in similar-sized sampling sites on other islands. There was frequency-based evidence of genetic structure between northern and southern sites on Santa Fé (F(st) of 0.0027-0.0115 for microsatellite and 0.0447-0.2391 for mtDNA), but the 4 southern sites showed little differentiation. Most of the intra-island genetic variation was allocated within rather than between sites. There was no evidence of sex-biased dispersal or population substructuring due to lek-mating behavior, suggesting that these 2 observed behaviors are not strong enough to leave an evolutionary signal on genetic patterns in this species.

  10. Salmonella infection in green anoles (Anolis carolinensis), an invasive alien species on Chichi Island of the Ogasawara archipelago in Japan.

    Science.gov (United States)

    Sumiyama, Daisuke; Izumiya, Hidemasa; Kanazawa, Tomoko; Murata, Koichi

    2014-03-01

    We investigated the presence of Salmonella in the green anole (Anolis carolinensis), an invasive alien species on Chichi Island, Japan. Samples were also collected from feral goats and public toilets on the island to examine infectious routes. Salmonellae were isolated from 27.1% of 199 samples; 32.6% of 141 cloacal samples from anoles, 62.5% of 8 intestinal samples from anole carcasses, 16.7% of 12 fecal samples from goats and 2.6% of 38 toilet bowl swabs. The serotype of most isolates was Salmonella Oranienburg (94.4% of 54). Although we did not confirm the infection pathways, our results indicated that green anoles are a risk factor as a source of Salmonella for public health. It is important to consider endemic pathogens that may be amplified by alien species within their introduced areas.

  11. Chlorine isotope composition of volcanic rocks and gases at Stromboli volcano (Aeolian Islands, Italy): Inferences on magmatic degassing prior to 2014 eruption

    Science.gov (United States)

    Liotta, Marcello; Rizzo, Andrea L.; Barnes, Jaime D.; D'Auria, Luca; Martelli, Mauro; Bobrowski, Nicole; Wittmer, Julian

    2017-04-01

    Among the magmatic volatiles, chlorine (Cl) is degassed at shallow depths offering the opportunity to investigate the behavior of magmatic degassing close to the surface, and the possible occurrence of chemical and isotopic fractionation related to gas/melt partitioning. However, it is still unclear if the isotopic composition of Cl (δ37Cl) can be used as a proxy of magmatic degassing. In this work, we investigate the concentrations of chlorine and sulfur, and the Cl isotope composition of rocks and plume gases collected at Stromboli volcano, Aeolian Islands, Italy. This volcano was chosen because it is characterized by persistent eruptive activity (i.e., Strombolian explosions) and by the presence of magma at very shallow levels in the conduits. Rocks belonging to the different magmatic series erupted throughout the formation of the volcano have δ37Cl values ranging between - 1.0 and + 0.7‰. The isotopic composition seems independent of the Cl concentration of the rocks, but shows a negative correlation with SiO2 content. Plume gases have a greater isotopic compositional variability than the rocks (- 2.2‰ ≤ δ37Cl ≤ + 1.5‰) and the composition seems related to the level of volcanic activity at Stromboli. Gases collected in 2011-2013 during days of ordinary eruptive activity are characterized by δ37Cl values ranging from + 0.3 to + 1.5‰ and S/Cl molar ratios between 1.4 and 2.2, similar to previous S/Cl measurements performed at Stromboli with other techniques. Plume gases collected in July 2014, in days of high-level eruptive activity preceding the onset of the 2014 effusive eruption, have negative δ37Cl values (- 2.2‰ ≤ δ37Cl ≤ - 0.1‰) and S/Cl between 0.9 and 1.2, which are among the lowest S/Cl values measured at this volcano. The amplitude of the volcanic tremor and the variation in the inclination of very long period (VLP) seismic signal polarization clearly indicate that in July 2014 the intensity and frequency of Strombolian

  12. Subsidence and current strain patterns on Tenerife Island (Canary Archipelago, Spain) derived from continuous GNSS time series (2008-2015)

    Science.gov (United States)

    Sánchez-Alzola, A.; Martí, J.; García-Yeguas, A.; Gil, A. J.

    2016-11-01

    In this paper we present the current crustal deformation model of Tenerife Island derived from daily CGPS time series processing (2008-2015). Our results include the position time series, a global velocity estimation and the current crustal deformation on the island in terms of strain tensors. We detect a measurable subsidence of 1.5-2 mm/yr. in the proximities of the Cañadas-Teide-Pico Viejo (CTPV) complex. These values are higher in the central part of the complex and could be explained by a lateral spreading of the elastic lithosphere combined with the effect of the drastic descent of the water table in the island experienced during recent decades. The results show that the Anaga massif is stable in both its horizontal and vertical components. The strain tensor analysis shows a 70 nstrain/yr. E-W compression in the central complex, perpendicular to the 2004 sismo-volcanic area, and 50 nstrain/yr. SW-NE extension towards the Northeast ridge. The residual velocity and strain patterns coincide with a decline in volcanic activity since the 2004 unrest.

  13. The geology and geochemistry of Isla Marchena, Galapagos Archipelago: An ocean island adjacent to a mid-ocean ridge

    Science.gov (United States)

    Vicenzi, E. P.; McBirney, A. R.; White, W. M.; Hamilton, M.

    1990-06-01

    Isla Marchena is the subaerial exposure of a shield volcano located between the Galapagos Platform and the Galapagos Spreading Center. The geologic evolution of the island can be divided into two lava series separated by formation of a cadera and a period of explosive activity. Both lava series contain evolved alkali olivine and tholeiitic basalts (average mg # = 55.2) and are virtually aphyric with the exception of a plagioclase-rich horizon in the pre-caldera section. Although the major-element compositions of the two series are similar, the abundances of incompatible elements and ratios of highly/moderately incompatible elements increase systematically with decreasing stratigraphic age. These compositional differences, together with textural and mineral chemical evidence for disequilibrium, are not easily explained by any single petrologic mechanism. The combined effects of a periodically replenished magma chamber, assimilation-fractionation, and in situ crystallization of a solidification zone are possible mechanisms that may be responsible for the temporal changes in lava composition. MORB-like abundances of trace elements, in addition to unusually depleted 87Sr/ 86Sr and 143Nd/ 144Nd ratios for ocean-island basalts, suggest that magmas associated with the Galapagos plume interacted with those of the Galapagos Spreading Center.

  14. Epiclastic deposits associated with large-scale landslides and the formation of erosive calderas in oceanic islands: The example of the La Palma Island (Canary Archipelago)

    Science.gov (United States)

    Colmenero, J. R.; de la Nuez, J.; Casillas, R.; Castillo, C.

    2012-12-01

    The growth and evolution of the La Palma Island has frequently been punctuated by high magnitude mass-wasting events triggered by gravitational collapses of volcanic edifices and by the erosion of the Caldera de Taburiente. These episodes are evidenced by voluminous debris accumulations in the submarine vicinity of the island and the presence of six very-coarse epiclastic units in the geological record of the island. In this paper we study these epiclastic units in order to characterize their stratigraphic architecture and facies associations, and the mechanisms involved in the transport and emplacement of the material associated with large failures and the erosion of volcanic edifices. Emphasis is also placed on characterising the temporal sequence of processes that have occurred on the island and discussing the origin of the Caldera de Taburiente. Three of the units described - La Cumbrecita Breccias and Megabreccias, La Pared de la Caldera Breccias and Conglomerates and La Viña Breccias - are overlying the detachment surfaces of the Santa Cruz de La Palma, Playa de la Veta and Cumbre Nueva landslides, respectively. They mainly represent the products of debris avalanches and debris flows with subordinate stream-flows filling the scars of the landslides. Unit 4, Las Angustias Breccias and Conglomerates, is interpreted as debris-flow or lahar deposits generated by landslides during the growth of the Bejenado Volcano. The uppermost units, the Tazacorte Conglomerates and El Riachuelo Conglomerates, represent water-laid deposits related to the excavation and erosion of the Caldera de Taburiente, and the incision of a valley between the Bejenado Volcano and the Cumbre Nueva scarp, respectively. Our results provide new and valuable data about cyclic events of construction-destruction of volcanic edifices worldwide, and their related processes and deposits.

  15. Continuous SO2 flux measurements for Vulcano Island, Italy

    Directory of Open Access Journals (Sweden)

    Fabio Vita

    2012-06-01

    Full Text Available The La Fossa cone of Vulcano Island (Aeolian Archipelago, Italy is a closed conduit volcano. Today, Vulcano Island is characterized by sulfataric activity, with a large fumarolic field that is mainly located in the summit area. A scanning differential optical absorption spectroscopy instrument designed by the Optical Sensing Group of Chalmers University of Technology in Göteborg, Sweden, was installed in the framework of the European project "Network for Observation of Volcanic and Atmospheric Change", in March 2008. This study presents the first dataset of SO2 plume fluxes recorded for a closed volcanic system. Between 2008 and 2010, the SO2 fluxes recorded showed average values of 12 t.d–1 during the normal sulfataric activity of Vulcano Island, with one exceptional event of strong degassing that occurred between September and December, 2009, when the SO2 emissions reached up to 100 t.d–1.

  16. Biogeographic, climatic and spatial drivers differentially affect α, β and γ diversities on oceanic archipelagos

    NARCIS (Netherlands)

    J.S. Cabral; P. Weigelt; W.D. Kissling; H. Kreft

    2014-01-01

    Island biogeographic studies traditionally treat single islands as units of analysis. This ignores the fact that most islands are spatially nested within archipelagos. Here, we took a fundamentally different approach and focused on entire archipelagos using species richness of vascular plants on 23

  17. Seroprevalence of Toxoplasma gondii in seabirds from Abrolhos Archipelago, Brazil

    Science.gov (United States)

    Toxoplasma gondii is a coccidian parasite that infects almost all warm-blooded animals, including birds. Abrolhos is an archipelago of five islands, located in the Atlantic Ocean, 56 nautical kilometers from the south coast of the state of Bahia, northeastern Brazil. Part of this archipelago is a Na...

  18. Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago.

    Science.gov (United States)

    de Pina-Araujo, Isabel Inês M; Guimarães, Monick L; Bello, Gonzalo; Vicente, Ana Carolina P; Morgado, Mariza G

    2014-01-01

    HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010-2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1-75) and 47 (IQR = 12-84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented.

  19. Sighting frequency and relative abundance of bottlenose dolphins (Tursiops truncatus along the northeast coast of Margarita Island and Los Frailes Archipelago, Venezuela

    Directory of Open Access Journals (Sweden)

    Lenin Oviedo

    2005-09-01

    Full Text Available The study of local cetaceans in Venezuela has a very recent history, and few efforts have been made in the assessment of coastal populations based on field research. The occurrence of whales and dolphins along the northeast coast of Venezuela has been documented through sightings and stranding records. Given the underwater topographical features and the influence of upwelling processes, this area is considered a very productive coastal ecosystem. Our objective was to establish the sighting frequency and relative abundance of bottlenose dolphins in the area. Sighting records were gathered on bottlenose dolphins and other cetacean species occurring along the northeast coast of Margarita Island and Los Frailes Archipelago through direct observation during land-based (6 surveys, 48 hours of observation and boat-based surveys (24 surveys, 121 hours of observation, 1295 km covered. A sighting frequency was calculated using two methodologies and then compared, considering: 1 a mean effective observation time (4.27 hours, and 2 distance covered with cetacean sightings (1108 km. A third method is proposed relating a mean effective distance covered with cetacean sightings and expressed as a percentage. The abundance index was calculated using the mean effective observation time. The sighting frequency of Tursiops truncatus in the study area was 3 - 4 sightings per day of 4.27 observation hours, or by 185 kilometers covered. The relative abundance was calculated as 35 dolphins in the study area, so a total population of less than 60 dolphins could inhabit the proposed range. Tursiops truncatus is the dominant species in the northeast coast of Margarita Island and Los Frailes Archipelago with 70% of all the sightings, so this locality could be termed as the distribution range of a possible local population of bottlenose dolphins. Rev. Biol. Trop. 53(3-4: 595-600. Epub 2005 Oct 3.El estudio de cetáceos locales en Venezuela tiene una historia bien reciente

  20. Bulk rock composition and geochemistry of olivine-hosted melt inclusions in the Grey Porri Tuff and selected lavas of the Monte dei Porri volcano, Salina, Aeolian Islands, southern Italy

    Science.gov (United States)

    Doherty, Angela L.; Bodnar, Robert J.; De Vivo, Benedetto; Bohrson, Wendy A.; Belkin, Harvey E.; Messina, Antonia; Tracy, Robert J.

    2012-01-01

    The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical mineral assemblage of the GPT is calcic plagioclase, clinopyroxene (augite), olivine (Fo72−84) and orthopyroxene (enstatite) ± amphibole and Ti-Fe oxides. The lava units show a similar mineral assemblage, but contain lower Fo olivines (Fo57−78). The lava units also contain numerous glomerocrysts, including an unusual variety that contains quartz, K-feldspar and mica. Melt inclusions (MI) are ubiquitous in all mineral phases from all units of the Monte dei Porri eruptions; however, only data from olivine-hosted MI in the GPT are reported here. Compositions of MI in the GPT are typically basaltic (average SiO2 of 49.8 wt %) in the pumices and basaltic-andesite (average SiO2 of 55.6 wt %) in the scoriae and show a bimodal distribution in most compositional discrimination plots. The compositions of most of the MI in the scoriae overlap with bulk rock compositions of the lavas. Petrological and geochemical evidence suggest that mixing of one or more magmas and/or crustal assimilation played a role in the evolution of the Monte dei Porri magmatic system, especially the GPT. Analyses of the more evolved mineral phases are required to better constrain the evolution of the magma.

  1. REST Service - Resource Assessment Investigation of the Mariana Archipelago (RAIOMA)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data service represents a subset of fisheries research carried out by the Pacific Island Fisheries Science Center (PIFSC) in the Mariana Archipelago. Specific...

  2. A reappraisal of the stratigraphy and chronology of Early Pliocene palaeontological sites from Lanzarote Island containing fossil terrestrial animals

    Science.gov (United States)

    Lomoschitz, Alejandro; Sánchez Marco, Antonio; Huertas, María José; Betancort, Juan F.; Isern, Arnau; Sanz, Elena; Meco, Joaquín

    2016-11-01

    The Famara massif, in the north of Lanzarote Island, constitutes the remains of a former island inhabited by the oldest known vertebrate fauna of the Canary archipelago off the coast of Africa. In this study, new ages are offered for the underlying and overlying basaltic lava flows of two paleontological sites. The island's three major palaeontological sites, which contain remains of this ancient fauna (Valle Grande, Valle Chico and Fuente de Gusa), are intercorrelated according to their lithologies, sedimentology, palaeontological content and geochronology. The new K/Ar age interval for the fossiliferous sedimentary deposits ranges between 4.3 ± 0.7 and 3.78 ± 0.71 Ma, within the Early Pliocene, and shows that the first known terrestrial animals in Lanzarote were present on the island for about 500 ka. The principal component of the deposits is a bioclastic calcarenite of aeolian origin (sand sheet deposits), which is present in all three sites and constitutes 65% of the beds. The remaining 35% is of fluvial-aeolian origin (mainly stream deposits). All the beds contain the same fossils (insect egg pods, land snails, avian eggshells and tortoise eggshells). The local palaeogeography and the formation of the deposits were conditioned by a flat plain, larger than 16 km2, over which aeolian sands moved freely with a prevailing NNE-WSW wind direction. In agreement with previous investigations, the palaeoclimate in this interval (ca. 4.3 to 3.8 Ma) must have been mainly dry with some rainy episodes.

  3. Does diet in lacertid lizards reflect prey availability? Evidence for selective predation in the Aeolian wall lizard, Podarcis raffonei (Mertens, 1952 (Reptilia, Lacertidae

    Directory of Open Access Journals (Sweden)

    Pietro Lo Cascio

    2011-06-01

    Full Text Available In this paper the invertebrate fauna occurring on Scoglio Faraglione, a tiny Aeolian island (AeolianArchipelago, NE Sicily inhabited by a population of the critically endangered lacertid lizard Podarcis raffonei(Mertens, 1952, was censused at different seasons and the resulting data were then compared with dataobtained analysing prey composition and prey abundance in the diet of the lizards occurring on the same islet.The diet of Podarcis raffonei was mainly based on insects and other arthropods. The results indicate that dietcomposition is not directly influenced by prey availability and temporal prey abundance, and that there isstrong evidence indicating selective predation. Lizards prey upon a number of arthropod categories fewer thanthat recorded in field. Some invertebrate taxa (e.g. Diptera and Gastropoda are really less attractive for lizardsand are rarely preyed or not preyed at all despite their spatial and/or temporal abundance. This suggests thatPodarcis raffonei is able to operate a hierarchical choice within the range of prey items constituting its preyspectrum, probably through the ability to discriminate between prey chemicals or visually oriented predation.

  4. Contemporary research in aeolian geomorphology

    Science.gov (United States)

    Bauer, B. O.

    2009-04-01

    The first International Conference on Aeolian Geomorphology (ICAR) was held in 1986, and every four years since then, aeolian geomorphologists from around the world have assembled to discuss their research and to showcase recent advancements in understanding and modeling of aeolian processes. A content analysis of the "Bibliography of Aeolian Research" [Stout, J.E., Warren, A., Gill, T.E., 2009. Publication trends in aeolian research: An analysis of the Bibliography of Aeolian Research. Geomorphology 105, 6-17 (this volume)] shows that the number of publications on aeolian topics has increased exponentially from the mid-20th Century with approximately 50 publications per year to about 500 publications per year when the first ICAR was held, to almost 1000 publications per year currently. Areas of focus have shifted historically from initial concerns with aeolian erosion and dust events as isolated phenomenon of localized curiosity or only regional importance, to comprehensive physically-based investigations and modeling of the mechanics of aeolian transport. Recently, more applied studies have been motivated by the recognition of the importance of aeolian processes to dust emissions into the atmosphere (with relevance for human health and for meteorological conditions and climate change) and within regional management contexts (especially on coasts where impending sea-level rise is of great concern and in arid and semi-arid environments given the dependence of sediment surface stability and remobilization on meteorological and ecological conditions). Aeolian geomorphology is a rapidly growing sub-discipline of Geomorphology that offers rich opportunities for interdisciplinary collaborations with colleagues from the Atmospheric Sciences, Climatology, Sedimentology, Quaternary Geology, Fluid Mechanics, Physics, Mathematics, Computer Science, Physical Geography, Ecology, and Agricultural Sciences, as well as our counterparts in fluvial, coastal, and arid

  5. Aeolian sand transport and aeolian deposits on Venus: A review

    Science.gov (United States)

    Kreslavsly, Mikhail A.; Bondarenko, Nataliya V.

    2017-06-01

    We review the current state of knowledge about aeolian sand transport and aeolian bedforms on planet Venus. This knowledge is limited by lack of observational data. Among the four planetary bodies of the Solar System with sufficient atmospheres in contact with solid surfaces, Venus has the densest atmosphere; the conditions there are transitional between those for terrestrial subaerial and subaqueous transport. The dense atmosphere causes low saltation threshold and short characteristic saltation length, and short scale length of the incipient dunes. A few lines of evidence indicate that the typical wind speeds exceed the saltation threshold; therefore, sand transport would be pervasive, if sand capable of saltation is available. Sand production on Venus is probably much slower than on the Earth; the major terrestrial sand sinks are also absent, however, lithification of sand through sintering is expected to be effective under Venus' conditions. Active transport is not detectable with the data available. Aeolian bedforms (transverse dunes) resolved in the currently available radar images occupy a tiny area on the planet; however, indirect observations suggest that small-scale unresolved aeolian bedforms are ubiquitous. Aeolian transport is probably limited by sand lithification causing shortage of saltation-capable material. Large impact events likely cause regional short-term spikes in aeolian transport by supplying a large amount of sand-size particles, as well as disintegration and activation of older indurated sand deposits. The data available are insufficient to understand whether the global aeolian sand transport occurs or not. More robust knowledge about aeolian transport on Venus is essential for future scientific exploration of the planet, in particular, for implementation and interpretation of geochemical studies of surface materials. High-resolution orbital radar imaging with local to regional coverage and desirable interferometric capabilities is the

  6. Modeled Population Connectivity across the Hawaiian Archipelago.

    Science.gov (United States)

    Wren, Johanna L K; Kobayashi, Donald R; Jia, Yanli; Toonen, Robert J

    2016-01-01

    We present the first comprehensive estimate of connectivity of passive pelagic particles released from coral reef habitat throughout the Hawaiian Archipelago. Potential connectivity is calculated using a Lagrangian particle transport model coupled offline with currents generated by an oceanographic circulation model, MITgcm. The connectivity matrices show a surprising degree of self-recruitment and directional dispersal towards the northwest, from the Main Hawaiian Islands (MHI) to the northwestern Hawaiian Islands (NWHI). We identify three predicted connectivity breaks in the archipelago, that is, areas in the mid and northern part of the archipelago that have limited connections with surrounding islands and reefs. Predicted regions of limited connectivity generally match observed patterns of genetic structure reported for coral reef species in the uninhabited NWHI, but multiple genetic breaks observed in the inhabited MHI are not explained by passive dispersal. The better congruence in our modeling results based on physical transport of passive particles in the low-lying atolls of the uninhabited NWHI, but not in the anthropogenically impacted high islands of the MHI begs the question: what ultimately controls connectivity in this system?

  7. Revealing magma degassing below closed-conduit active volcanoes: Geochemical features of volcanic rocks versus fumarolic fluids at Vulcano (Aeolian Islands, Italy)

    Science.gov (United States)

    Mandarano, Michela; Paonita, Antonio; Martelli, Mauro; Viccaro, Marco; Nicotra, Eugenio; Millar, Ian L.

    2016-04-01

    The elemental and isotopic compositions of noble gases (He, Ne, and Ar) in olivine- and clinopyroxene-hosted fluid inclusions have been measured for rocks at various degrees of evolution and belonging to high-K calcalkaline-shoshonitic and shoshonitic-potassic series in order to cover the entire volcanological history of Vulcano Island (Italy). The major- and trace-element concentrations and the Sr- and Pb-isotope compositions for whole rocks were integrated with data obtained from the fluid inclusions. 3He/4He in fluid inclusions is within the range of 3.30 and 5.94 R/Ra, being lower than the theoretical value for the deep magmatic source expected for Vulcano Island (6.0-6.2 R/Ra). 3He/4He of the magmatic source is almost constant throughout the volcanic history of Vulcano. Integration of the He- and Sr-isotope systematics leads to the conclusion that a decrease in the He-isotope ratio of the rocks is mainly due to the assimilation of 10-25% of a crustal component similar to the Calabrian basement. 3He/4He shows a negative correlation with Sr isotopes except for the last-erupted Vulcanello latites (Punta del Roveto), which have anomalously high He isotope ratios. This anomaly has been attributed to a flushing process by fluids coming from the deepest reservoirs, since an input of deep magmatic volatiles with high 3He/4He values increases the He-isotope ratio without changing 87Sr/86Sr. A comparison of the He-isotope ratios between fluid inclusions and fumarolic gases shows that only the basalts of La Sommata and the latites of Vulcanello have comparable values. Taking into account that the latites of Vulcanello relate to one of the most-recent eruptions at Vulcano (in the 17th century), we infer that the most probable magma which actually feeds the fumarolic emissions is a latitic body that ponded at about 3-3.5 km of depth and is flushed by fluids coming from a deeper and basic magma.

  8. Revealing the magmas degassing below closed-conduit active volcanoes: noble gases in volcanic rocks versus fumarolic fluids at Vulcano (Aeolian Islands, Italy)

    Science.gov (United States)

    Mandarano, Michela; Paonita, Antonio; Martelli, Mauro; Viccaro, Marco; Nicotra, Eugenio; Millar, Ian L.

    2016-04-01

    With the aim to constrain the nature of magma currently feeding the fumarolic field of Vulcano, we measured the elemental and isotopic compositions of noble gases (He, Ne, and Ar) in olivine- and clinopyroxene-hosted fluid inclusions in high-K calcalcaline-shoshonitic and shoshonitic-potassic series so as to cover the entire volcanological history of Vulcano Island (Italy). The major and trace-element concentrations and the Sr- and Pb-isotope compositions for whole rocks were integrated with data obtained from the fluid inclusions. 3He/4He in fluid inclusions is within the range of 3.30 and 5.94 R/Ra, being lower than the value for the deep magmatic source expected for Vulcano Island (6.0-6.2 R/Ra). 3He/4He of the magmatic source is almost constant throughout the volcanic record of Vulcano. Integration of the He- and Sr-isotope systematics leads to the conclusion that a decrease in the He-isotope ratio of the rocks is mainly due to the assimilation of 10-25% of a crustal component similar to the Calabrian basement. 3He/4He shows a negative correlation with Sr isotopes except for the last-emitted Vulcanello latites (Punta del Roveto), which have high He- and Sr-isotope ratios. This anomaly has been attributed to a flushing process by fluids coming from the deepest reservoirs. Indeed, an input of deep magmatic volatiles with high 3He/4He values increases the He-isotope ratio without changing 87Sr/86Sr. A comparison of the He isotope ratios between fluid inclusions and fumarolic gases showed that only the basalts of La Sommata and the latites of Vulcanello have comparable values. Taking into account that the latites of Vulcanello relate to one of the most-recent eruptions at Vulcano (in the 17th century), we infer that that the most probable magma which actually feeds the fumarolic emissions is a latitic body ponding at about 3-3.5 km of depth and flushed by fluids coming from a deeper and basic magma.

  9. The effect of steam-heating processes on the chemical and isotopic composition of the shallow thermal aquifer in Vulcano Island (Aeolian Arc, Sicily).

    Science.gov (United States)

    Capasso, G.; Federico, C.; Madonia, P.; Paonita, A.

    2012-04-01

    We report on a comprehensive study of major-ion chemistry, dissolved gases, and stable isotopes measured in water wells at Vulcano Island since 1988. Particularly, we focus on chemical and hydrological modifications of groundwaters observed in the last two decades, interpreted according to a quantitative model describing steam condensation and boiling phenomena in shallow water bodies (Federico et al., 2010). According to this model, we infer that (i) strong isotope enrichment observed in some shallow thermal waters can result from an increasing mass rate of condensing deep vapor, even in water being meteoric in origin; (ii) the high pCO2 measured in the coldest and peripheral waters are explained by the progressive CO2 enrichment in the vapor phase during multistep boiling; and (iii) the high Cl- and SO4-- contents in the hottest waters can be attributed to the direct condensation (single-step) of volcanic vapor. The model also takes into account both the mass fluxes and the compositions of the involved endmembers (steam and shallow groundwater), which provides important inferences on the modifications observed during the periods of increasing mass and heat input from depth occurred at Vulcano Island. The volcanic crisis that occurred in 1988-1993 profoundly affected the composition of some thermal wells that were more-directly affected by ascending vapour. In particular, higher Cl-, SO4--, and HCO3- contents, temperature, and pCO2 values were measured. These variations are all explained by a different composition of the vapor entering the aquifer paralleled by a higher mass rate relative to the shallow meteoric endmember. Minor effects on the shallow thermal aquifer are observed during the following periods of increasing heat and mass flux from depth, mostly recorded in the crater area. This implies that the shallow thermal aquifer is affected by magmatic fluids ascending along central conduits only when there is a significant increase in the heat and mass fluxes

  10. Comparisons of N- and P-limited productivity between high granitic islands versus low carbonate atolls in the Seychelles Archipelago: a test of the relative-dominance paradigm

    Science.gov (United States)

    Littler, M. M.; Littler, D. S.; Titlyanov, E. A.

    1991-12-01

    This exploratory study suggests that different geological systems (carbonate vs. granitic) in tropical waters have contrasting patterns of photosynthetic nutrient limitation correlated with inorganic nitrogen (N) and phosphorus (P) availability. Physiological assays for 21 predominant macrophyte species show that inorganic N and P are much less limiting to photosynthesis on granitic islands than is the case on carbonate islands and that, of the two, P is more likely to limit production in carbonate-rich tropical waters. Patterns of nutrient limitation in turn are reflected by differences in the relative dominance of functional groups of sessile, epilithic, photosynthetic organisms. Surveys at 33 sites on 10 islands revealed that nearshore waters on high granitic islands tend to be characterized by large and species-rich standing stocks of frondose macroalgae, often dominated by Sargassum spp., whereas waters around low carbonate islands tend to be dominated by hermatypic corals. Macrophyte tissue and seawater analyses also indicate a possible trend toward higher levels of N and P in granitic vs. carbonate islands. Pagode Island, a low carbonate island influenced by guano from seabird colonies, is an exception, with few corals, relatively high levels of tissue and seawater N and P, and a predominance of macroalgae (mostly Dictyosphaeria cavernosa).

  11. [Vegetation landscape health assessment in Changshan Archipelago, North Yellow Sea].

    Science.gov (United States)

    Suo, An-ning; Sun, Yong-guang; Li, Bin-yong; Lin, Yong; Zhang, Yong-hua

    2015-04-01

    Island vegetation is an important component of island ecosystem. Multi-targets of island ecosystem health integrated with landscape ecology theory were employed to construct the index system for island vegetation health assessment in terms of landscape vigor, landscape stressing intensity and landscape stability. The Changshan Archipelago in the North Yellow Sea was chosen as a case to apply the island vegetation health assessment index system. The results showed that the overall vegetation health status in Changshan Archipelago was good and had a big island variation. The vegetation health index for Haiyang Island and Zhangzi Island was above 0.80, belonging to first eco-health level area, whereas that for Dachangshan Island, Xiaochangshan Island and Dawangjia Island ranged from 0.70 to 0.80, which could be categorized as the second eco-health level area. Guanglu Island and Shichen Island could be termed as the third eco-health level area with the vegetation health index below 0.70. The distance of island to mainland, area of island together with industrial structure were the main driving forces for the variation of vegetation landscape heath between different islands.

  12. To the knowledge of cuckoo wasps (Hymenoptera: Chrysididae) of the Balearic Archipelago, Spain.

    Science.gov (United States)

    Strumia, Franco; Gayubo, Severiano Fernández

    2013-01-01

    The Chrysididae of the Balearic Archipelago were studied by operating four Malaise traps in the Mallorca and Menorca Islands. Traps captured 98 individuals belonging to 19 species. Including all available data from literature, the number of species in this archipelago rise to 34. Hedychridium balearicum Strumia, sp. nov (Mallorca) is described and key to the Hedychridium monochroum species-group is given. Extrapolation from available data suggests the presence of about 58 to 107 Chrysididae species in the Balearic Archipelago.

  13. Impact and Epidemiological Investigations into the Incursion and Spread of Peste des Petits Ruminants in the Comoros Archipelago: An Increased Threat to Surrounding Islands.

    Science.gov (United States)

    Cêtre-Sossah, C; Kwiatek, O; Faharoudine, A; Soulé, M; Moutroifi, Y O; Vrel, M A; Salami, H; Rassoul, S; Asnaoui, M; Moindjie, Y; Albina, E; Libeau, G; Cardinale, E

    2016-08-01

    Late October 2012, a great number of deaths of unknown origin occurred in goat herds in the suburbs of Ngazidja, located in the Comoros archipelago. Few weeks later, laboratory testing requested by the animal health authorities resulted in the identification of peste des petits ruminants (PPR) infection. Notably, the Index case could be attributed to a sick goat imported from Tanzania. Viral isolation was successful from the lungs leading to the whole N nucleoprotein gene sequencing. Phylogenetic analysis revealed that the strain belongs to the lineage III which includes strains of eastern African origin. In addition, to evaluate the impact of PPR on the Comorian indigenous domesticated ruminant population, a cross-sectional PPR serological survey was conducted between April and July 2013. A low overall PPRV antibody prevalence 2.24% (95% CI [1.38; 3.08]) was detected with a Grande Comore prevalence of 3.34% (IC = [2.09; 4.63]) with a limited spread of the disease mainly due to farm practices such as limited contacts between farm animals and rapid slaughtering of sick animals. © 2014 Blackwell Verlag GmbH.

  14. New record of sheep frog (Hypopachus variolosus in the Tres Marías Islands archipelago, Nayarit, Mexico Nuevo registro de la rana ovejera (Hypopachus variolosus en el archipiélago de las islas Marías, Nayarit, México

    Directory of Open Access Journals (Sweden)

    J. Antonio de la Torre

    2010-08-01

    Full Text Available During a recent visit to María Madre Island, in the Tres Marías Island archipelago, 2 specimens of Hypopachus variolosus were found. This new record of the sheep frog from Tres Marías Island archipelago represents the first island record for this species. Due to the uncertainty about its conservation status in this locality, we consider necessary to improve the information about this species in the island.Durante una reciente vista a la isla María Madre del archipiélago de las islas Marías se encontraron 2 ejemplares de Hypopachus variolosus. Este nuevo registro de la rana ovejera en las islas Marías representa el primero de esta especie para una isla. Consideramos que es necesario obtener más información de esta especie en el archipiélago ya que su estado de conservación en esta localidad es incierto.

  15. Alpheid shrimps (Decapoda: Caridea) of the Trindade & Martin Vaz Archipelago, off Brazil, with new records, description of a new species of Synalpheus and remarks on zoogeographical patterns in the oceanic islands of the tropical southern Atlantic.

    Science.gov (United States)

    Anker, Arthur; Tavares, Marcos

    2016-01-01

    The present study deals with shrimps of the family Alpheidae collected in the shallow waters around the remote Trindade & Martin Vaz Archipelago, situated 1200 km off the coast of Espírito Santo, Brazil. A few additional samples came from dredges on top of the seamounts of the Vitória-Trindade Seamount Chain. A total of 23 species in eight genera are reported, the vast majority representing new records for the area. One species is described as new, Synalpheus trinitatis sp. nov., based on the type material from Trindade Island. The new species clearly belongs to the Synalpheus brooksi Coutière, 1909 species complex, differing from all its other members by at least two morphological features. Four species represent new records for Brazil and the southwestern Atlantic: Alpheopsis aequalis Coutière, 1897 sensu lato, Alpheopsis chalciope de Man, 1910 sensu lato, Alpheus crockeri (Armstrong, 1941) and Prionalpheus gomezi Martínez-Iglesias & Carvacho, 1991; the two species of Alpheopsis are recorded from the Atlantic Ocean for the first time. The colour pattern of the recently described Alpheus rudolphi Almeida & Anker, 2011, a species endemic to Brazil, is shown for the first time and compared to the colour patterns of the four closely related species of the A. armatus Rathbun, 1901 complex from the Caribbean-Florida region. A brief zoogeographical analysis of the alpheid fauna of the oceanic islands of the tropical southern Atlantic (Trindade & Martin Vaz, Fernando de Noronha, Atol das Rocas, São Pedro & São Paulo, Ascension, Saint Helena, Cape Verde, São Tomé & Príncipe) is also provided.

  16. Documenting the biodiversity of the Madrean Archipelago: An analysis of a virtual flora and fauna

    Science.gov (United States)

    Nicholas S. Deyo; Thomas R. Van Devender; Alex Smith; Edward. Gilbert

    2013-01-01

    The Madrean Archipelago Biodiversity Assessment (MABA) of Sky Island Alliance is an ambitious project to document the distributions of all species of animals and plants in the Madrean Archipelago, focusing particularly on northeastern Sonora and northwestern Chihuahua, Mexico. The information is made available through MABA’s online database (madrean.org). The sources...

  17. A new Ingolfiellid (Crustacea, Amphipoda, Ingolfiellidae from an anchialine pool on Abd al Kuri Island, Socotra Archipelago, Yemen

    Directory of Open Access Journals (Sweden)

    Valentina Iannilli

    2013-05-01

    Full Text Available Ingolfiella arganoi sp. n. from Abd al Kuri Island in the Arabian Sea is described from two specimens, a male and a female. The western shore of the Indian Ocean was hitherto a vacant spot in the distribution of circumtropical shallow marine interstitial ingolfiellids and therefore the location of the new species fills a meaningful gap in the geography of the family. Morphologically, the new species shows close affinities with I. xarifae from the Maldives.

  18. A new Ingolfiellid (Crustacea, Amphipoda, Ingolfiellidae) from an anchialine pool on Abd al Kuri Island, Socotra Archipelago, Yemen

    Science.gov (United States)

    Iannilli, Valentina; Vonk, Ronald

    2013-01-01

    Abstract Ingolfiella arganoi sp. n. from Abd al Kuri Island in the Arabian Sea is described from two specimens, a male and a female. The western shore of the Indian Ocean was hitherto a vacant spot in the distribution of circumtropical shallow marine interstitial ingolfiellids and therefore the location of the new species fills a meaningful gap in the geography of the family. Morphologically, the new species shows close affinities with Ingolfiella xarifae from the Maldives. PMID:23794897

  19. Population genetic structure of gray wolves (Canis lupus) in a marine archipelago suggests island-mainland differentiation consistent with dietary niche.

    Science.gov (United States)

    Stronen, Astrid V; Navid, Erin L; Quinn, Michael S; Paquet, Paul C; Bryan, Heather M; Darimont, Christopher T

    2014-06-10

    Emerging evidence suggests that ecological heterogeneity across space can influence the genetic structure of populations, including that of long-distance dispersers such as large carnivores. On the central coast of British Columbia, Canada, wolf (Canis lupus L., 1758) dietary niche and parasite prevalence data indicate strong ecological divergence between marine-oriented wolves inhabiting islands and individuals on the coastal mainland that interact primarily with terrestrial prey. Local holders of traditional ecological knowledge, who distinguish between mainland and island wolf forms, also informed our hypothesis that genetic differentiation might occur between wolves from these adjacent environments. We used microsatellite genetic markers to examine data obtained from wolf faecal samples. Our results from 116 individuals suggest the presence of a genetic cline between mainland and island wolves. This pattern occurs despite field observations that individuals easily traverse the 30 km wide study area and swim up to 13 km among landmasses in the region. Natal habitat-biased dispersal (i.e., the preference for dispersal into familiar ecological environments) might contribute to genetic differentiation. Accordingly, this working hypothesis presents an exciting avenue for future research where marine resources or other components of ecological heterogeneity are present.

  20. Population genetic structure of gray wolves (Canis lupus) in a marine archipelago suggests island-mainland differentiation consistent with dietary niche

    DEFF Research Database (Denmark)

    Stronen, Astrid Vik; Navid, Erin L; Quinn, Michael S;

    2014-01-01

    Background Emerging evidence suggests that ecological heterogeneity across space can influence the genetic structure of populations, including that of long-distance dispersers such as large carnivores. On the central coast of British Columbia, Canada, wolf (Canis lupus L., 1758) dietary niche...... mainland and island wolves. This pattern occurs despite field observations that individuals easily traverse the 30 km wide study area and swim up to 13 km among landmasses in the region. Conclusions Natal habitat-biased dispersal (i.e., the preference for dispersal into familiar ecological environments...

  1. The Galapagos archipelago: A natural laboratory to examine sharp hydroclimatic, geologic and anthropogenic gradients

    Science.gov (United States)

    Percy, Madelyn; Schmitt, Sarah; Riveros-Iregui, Diego; Mirus, Benjamin B.

    2016-01-01

    Poor understanding of the water cycle in tropical ecosystems has the potential to exacerbate water shortages and water crises in the region. We suggest that the Galápagos Islands provide an excellent proxy to regions across the tropics as a result of sharp hydroclimatic, anthropogenic, and pedohydrologic gradients across the archipelago. Hydroclimatic and pedohydrologic gradients are found across different elevations on single islands, as well as across the archipelago, whereas anthropogenic gradients reflect land use and land cover change across islands as population and growth in tourism have affected individual islands differently. This article highlights specific opportunities to further examine our understanding of the interactions between water and critical zone processes in tropical ecosystems, making connections between the Galápagos archipelago and much of the understudied tropics. The Galápagos archipelago offers a natural laboratory through which we can examine current threats to freshwater security as well as the dynamics of coupled natural and human systems.

  2. Mesh generation in archipelagos

    NARCIS (Netherlands)

    Terwisscha van Scheltinga, A.; Myers, P.G.; Pietrzak, J.D.

    2012-01-01

    A new mesh size field is presented that is specifically designed for efficient meshing of highly irregular oceanic domains: archipelagos. The new approach is based on the standard mesh size field that uses the proximity to the nearest coastline. Here, the proximities to the two nearest coastlines

  3. Description of Medwayella independencia (Siphonaptera, Stivaliidae, a new species of flea from Mindanao Island, the Philippines and their phoretic mites, and miscellaneous flea records from the Malay Archipelago

    Directory of Open Access Journals (Sweden)

    Michael Hastriter

    2014-05-01

    Full Text Available Medwayella independencia, a new species of flea, is described from the tupaiid host Urogale everetti (Thomas from Mindanao Island, Philippines. Several other species of fleas are also recorded from the Philippines including a single male of Lentistivalius philippinensis Hastriter & Bush, 2013 (previously known only from two males, the bat fleas Thaumapsylla breviceps orientalis Smit and Thaumapsylla longiforceps Traub, a single unidentified female species of Macrostylophora Ewing collected from the murid Bullimus bagobos Mearns, and a pair of Medwayella robinsoni ssp. from Sundasciurus hoogstraali (Sanborn from Busuanga Island, Philippines. Representatives of Medwayella Traub, 1972 and Macrostylophora have not previously been recorded from the Philippines. A key to the male sex of Medwayella is provided. Phoretic mites of the genus Psylloglyphus (family Winterschmidtiidae were present under the abdominal sclerites of several male and female specimens of M. independencia. This is the second report of a phoretic mite on a species of Medwayella Traub. The co-evolutionary implications between phoretic mites and fleas are discussed.

  4. Magmatic (silicates/saline/sulfur-rich/CO2) immiscibility and zirconium and rare-earth element enrichment from alkaline magma chamber margins : Evidence from Ponza Island, Pontine Archipelago, Italy

    Science.gov (United States)

    Belkin, H.E.; de Vivo, B.; Lima, A.; Torok, K.

    1996-01-01

    Fluid inclusions were measured from a feldspathoid-bearing syenite xenolith entrained in trachyte from Ponza, one of the islands of the Pontine Archipelago, located in the Gulf of Gaeta, Italy. The feldspathoid-bearing syenite consists mainly of potassium feldspar, clinopyroxene, amphibole, biotite, titanite, manganoan magnetite, apatite with minor nosean, Na-rich feldspar, pyrrhotite, and rare cheralite. Baddeleyite and zirkelite occur associated with manganoan magnetite. Detailed electron-microprobe analysis reveals enrichments in REE, Y, Nb, U, Th as well as Cl and F in appropriate phases. Fluid inclusions observed in potassium feldspar are either silicate-melt or aqueous inclusions. The aqueous inclusions can be further classified as. (1) one-phase vapor, (2) two-phase (V + L) inclusions, vapor-rich inclusions with a small amount of CO2 in most cases; homogenization of the inclusions always occurred in the vapor phase between 359 and 424??C, salinities vary from 2.9 to 8.5 wt. % NaCl equivalent; and. (3) three-phase and multiphase inclusions (hypersaline/sulfur-rich aqueous inclusions sometimes with up to 8 or more solid phases). Daughter minerals dissolve on heating before vapor/liquid homogenization. Standardless quantitative scanning electron microscope X-ray fluorescence analysis has tentatively identified the following chloride and sulfate daughter crystals; halite, sylvite, glauberite. arcanite, anhydrite, and thenardite. Melting of the daughter crystals occurs between 459 and 536??C (54 to 65 wt. % NaCI equivalent) whereas total homogenization is between 640 and 755??C. The occurrence of silicate-melt inclusions and high-temperature, solute-rich aqueous inclusions suggests that the druse or miarolitic texture of the xenolith is late-stage magmatic. The xenolith from Ponza represents a portion of the peripheral magma chamber wall that has recorded the magmatic/hydrothermal transition and the passage of high solute fluids enriched in chlorides, sulfur, and

  5. Meso-scale aeolian sediment input to coastal dunes: The nature of aeolian transport events

    Science.gov (United States)

    Delgado-Fernandez, Irene; Davidson-Arnott, Robin

    2011-03-01

    Observations of aeolian transport in coastal areas have focused on short-term experiments because of limitations imposed by instrumentation. This paper uses a case study at Greenwich Dunes, Prince Edward Island National Park, Canada, to analyze how sediment transport takes place at the beach over periods of weeks to months. A monitoring station provided hourly time series of vegetation cover, shoreline position, fetch distances, surficial moisture content, presence of ice and snow, wind speed and direction and transport processes over nine months. Analysis shows that high wind speeds may not generate any net transport into the dunes because of the limitations imposed by snow/ice cover, moisture, and short fetch distances. Despite extreme winds during intense storms, such events often lead to wave scarping rather than aeolian sediment input to the foredunes. When sediment was transported on the beach, the magnitude was regulated by a combination of factors including: angle of wind approach, fetch distance, moisture content, and duration of the wind event. In particular, angle of wind approach (and therefore fetch distance) may demote a high magnitude wind event with strong transport potential to one with no transport at all, which poses challenges for predicting the effects of individual storms over the course of several months. A significant proportion of sediment delivery to the foredunes was associated with wind events of low to medium magnitude. It is suggested here that large magnitude wind events have low probabilities of resulting in transport towards the foredune because factors such as wave inundation play an increasing role in preventing sediment movement across the beach. This has implications for modelling and management, and highlights differences between the magnitude and frequency of aeolian transport events in the coastal environment compared to those in deserts and to fluvial sediment transport.

  6. Complex systems in aeolian geomorphology

    Science.gov (United States)

    Baas, Andreas C. W.

    2007-11-01

    Aeolian geomorphology provides a rich ground for investigating Earth surface processes and landforms as complex systems. Sand transport by wind is a classic dissipative process with non-linear dynamics, while dune field evolution is a prototypical self-organisation phenomenon. Both of these broad areas of aeolian geomorphology are discussed and analysed in the context of complexity and a systems approach. A feedback loop analysis of the aeolian boundary-layer-flow/sediment-transport/bedform interactions, based on contemporary physical models, reveals that the system is fundamentally unstable (or at most meta-stable) and likely to exhibit chaotic behaviour. Recent field-experimental research on aeolian streamers and spatio-temporal transport patterns, however, indicates that sand transport by wind may be wholly controlled by a self-similar turbulence cascade in the boundary layer flow, and that key aspects of transport event time-series can be fully reproduced from a combination of (self-organised) 1/ f forcing, motion threshold, and saltation inertia. The evolution of various types of bare-sand dunes and dune field patterns have been simulated successfully with self-organising cellular automata that incorporate only simplified physically-based interactions (rules). Because of their undefined physical scale, however, it not clear whether they in fact simulate ripples (bedforms) or dunes (landforms), raising fundamental cross-cutting questions regarding the difference between aeolian dunes, impact ripples, and subaqueous (current) ripples and dunes. An extended cellular automaton (CA) model, currently under development, incorporates the effects of vegetation in the aeolian environment and is capable of simulating the development of nebkhas, blow-outs, and parabolic coastal dunes. Preliminary results indicate the potential for establishing phase diagrams and attractor trajectories for vegetated aeolian dunescapes. Progress is limited, however, by a serious lack of

  7. Formation of aeolian dunes on Anholt, Denmark since AD 1560

    DEFF Research Database (Denmark)

    Clemmensen, Lars B; Bjørnsen, Mette; Murray, Andrew;

    2007-01-01

    Sand dunes on the island of Anholt (Denmark) in the middle of Kattegat form a relatively barren, temperate climate Aeolian system, locally termed the "Desert". The dunes have developed on top of a raised beach ridge system under the influence of dominant winds from westerly directions....... They are relatively coarse-grained with an average mean grain size of 480 µm. The last phase of aeolian activity and dune formation on Anholt started after AD 1560, when the local pine forest was removed. Historical sources report intense sand mobilization in the 17th century, and new optically stimulated...... luminescence (OSL) dates indicate that dune formation continued until the end of the 19th century. This period of sand drift and dune formation took place during the later part of the Little Ice Age, which is characterized by increased (summer) storminess in large parts of NW Europe. Dune stabilization...

  8. Galapagos Islands

    Science.gov (United States)

    2002-01-01

    This true-color image of the Galapagos Islands was acquired on March 12, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The Galapagos Islands, which are part of Ecuador, sit in the Pacific Ocean about 1000 km (620 miles) west of South America. As the three craters on the largest island (Isabela Island) suggest, the archipelago was created by volcanic eruptions, which took place millions of years ago. Unlike most remote islands in the Pacific, the Galapagos have gone relatively untouched by humans over the past few millennia. As a result, many unique species have continued to thrive on the islands. Over 95 percent of the islands' reptile species and nearly three quarters of its land bird species cannot be found anywhere else in the world. Two of the more well known are the Galapagos giant tortoise and marine iguanas. The unhindered evolutionary development of the islands' species inspired Charles Darwin to begin The Origin of Species eight years after his visit there. To preserve the unique wildlife on the islands, the Ecuadorian government made the entire archipelago a national park in 1959. Each year roughly 60,000 tourists visit these islands to experience what Darwin did over a century and a half ago. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  9. Soil CO2 emissions at Furnas volcano, São Miguel Island, Azores archipelago: Volcano monitoring perspectives, geomorphologic studies, and land use planning application

    Science.gov (United States)

    Viveiros, FáTima; Cardellini, Carlo; Ferreira, Teresa; Caliro, Stefano; Chiodini, Giovanni; Silva, Catarina

    2010-12-01

    Carbon dioxide (CO2) diffuse degassing structures (DDS) at Furnas volcano (São Miguel Island, Azores) are mostly associated with the main fumarolic fields, evidence that CO2 soil degassing is the surface expression of rising steam from the hydrothermal system. Locations with anomalous CO2 flux are mainly controlled by tectonic structures oriented WNW-ESE and NW-SE and by the geomorphology of the volcano, as evidenced by several DDS located in depressed areas associated with crater margins. Hydrothermal soil CO2 emissions in Furnas volcano are estimated to be ˜968 t d-1. Discrimination between biogenic and hydrothermal CO2 was determined using a statistical approach and the carbon isotope composition of the CO2 efflux. Different sampling densities were used to evaluate uncertainty in the estimation of the total CO2 flux and showed that a low density of points may not be adequate to quantify soil emanations from a relatively small DDS. Thermal energy release associated with diffuse degassing at Furnas caldera is about 118 MW (from an area of ˜4.8 km2) based on the H2O/CO2 ratio in fumarolic gas. The DDS also affect Furnas and Ribeira Quente villages, which are located inside the caldera and in the south flank of the volcano, respectively. At these sites, 58% and 98% of the houses are built over hydrothermal CO2 emanations, and the populations are at risk due to potential high concentrations of CO2 accumulating inside the dwellings.

  10. The mystery of Bunge Land (New Siberian Archipelago): implications for its formation based on palaeoenvironmental records, geomorphology, and remote sensing

    Science.gov (United States)

    Schirrmeister, Lutz; Grosse, Guido; Kunitsky, Viktor V.; Fuchs, Margret C.; Krbetschek, Matthias; Andreev, Andrei A.; Herzschuh, Ulrike; Babyi, Olga; Siegert, Christine; Meyer, Hanno; Derevyagin, Alexander Y.; Wetterich, Sebastian

    2010-12-01

    Multiproxy datasets (geocryology, geochronology, sedimentology, palaeo-ecology) from permafrost exposures were used together with land surface information based on satellite imagery and thematic maps in order to reconstruct the Lateglacial to Holocene landscape and environmental dynamics of Bunge Land (Zemlya Bunge). This area of little relief, situated in the New Siberian Archipelago, connects the geomorphologically well-structured islands of Kotel'ny and Fadeevsky. A buried thermokarst landscape was found in the northwest region of the Bunge Land low terrace sand plain, whereas the Bunge Land high terrace seems to be an exposed residue of a similar late Quaternary thermokarst landscape. That is confirmed especially by radiocarbon accelerator mass spectrometry and optically stimulated luminescence age determinations, and by pollen analyses. Palaeogeographically, the late Pleistocene periglacial landscape and sedimentation of Bunge Land was closely connected to Kotel'ny and Fadeevsky; only later on seismotectonical block movements resulted in reshaping parts of Bunge Land. The Bunge Land low terrace area first subsided and the original landscape there was destroyed by marine inundation, followed by marine sedimentation. Subsequent block heave of the low terrace region exposed a vast sheet of marine sands which is continuously surficially reworked by aeolian processes, while the original alluvial plain landscape in the high terrace area was preserved and started degrading only by early Holocene thermokarst development. The studied exposures contain one of the northernmost (74.88°N) environmental records for the late Pleistocene-Holocene transition in the Eurasian Arctic.

  11. Oceanic archipelagos: a perspective on the geodynamics and biogeography of the World’s smallest biotic provinces

    Directory of Open Access Journals (Sweden)

    Kostas Triantis

    2016-07-01

    Full Text Available Since the contributions of Charles Darwin and Alfred Russel Wallace, oceanic archipelagos have played a central role in the development of biogeography. However, despite the critical influence of oceanic islands on ecological and evolutionary theory, our focus has remained limited to either the island-level of specific archipelagos or single archipelagos. Recently, it was proposed that oceanic archipelagos qualify as biotic provinces, with diversity primarily reflecting a balance between speciation and extinction, with colonization having a minor role. Here we focus on major attributes of the archipelagic geological dynamics that can affect diversity at both the island and the archipelagic level. We also re-affirm that oceanic archipelagos are appropriate spatiotemporal units to frame analyses in order to understand large scale patterns of biodiversity.

  12. Computer simulation of aeolian bedforms

    Institute of Scientific and Technical Information of China (English)

    苗天德; 慕青松; 武生智

    2001-01-01

    A discrete model is set up using the cellular automaton method and applied to simulate the formation and evolution of aeolian bedforms. The calculated bedforms resemble the actual shape of natural sand ripples and dunes.This reveals that the sand movement is a typical nonlinear dynamical process, and that the nesting configuration of sand ripples, dunes and draas are a self-organized system with a fractal characteristic, and evotves simultaneously at various scales in the sand-airflow.

  13. Energy Transition Initiative, Island Energy Snapshot - British Virgin Islands (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-03-01

    This profile provides a snapshot of the energy landscape of the British Virgin Islands (BVI), one of three sets of the Virgin Island territories in an archipelago making up the northern portion of the Lesser Antilles.

  14. Concentration and grain-size distribution of aeolian sands in peat bogs as an indicator of past storminess in coastal areas of Estonia

    Science.gov (United States)

    Vandel, Egert; Vaasma, Tiit; Tõnisson, Hannes; Sugita, Shinya; Vilumaa, Kadri; Anderson, Agnes; Terasmaa, Jaanus; Kangur, Mihkel; Pensa, Margus; Küttim, Martin; Umbleja, Liisa; Puusepp, Liisa

    2016-04-01

    Storminess in the Baltic Sea region has significantly increased over the last 50 years. As we do not have meteorological data beyond 20th century, therefore the long-term changes in storminess (e.g., frequency and magnitude of the storms) and its impact on the coastal evolution are mostly unknown. This study aims to reconstruct the extreme storm events along the coast of Estonia in late Holocene, inferred from changes in grain-size distribution and concentration of aeolian sands preserved in peat deposits. Four cores in total were collected from bogs of coastal Estonia; three from west Estonian archipelago (Hiiumaa Island and Saaremaa Island); one from the northern coast of the mainland (Juminda Peninsula). Core from Saaremaa (166 cm) covers the last 2700 years, cores from Hiiumaa (171 cm and 330 cm) cover ca 4000 years, and core from Juminda (465 cm) covers ca 8500 years. All AMS dates (77) are converted to cal yrs BP. Analyses of LOI and grain size are carried out at every centimetre in order to obtain data for mineral matter content and concentration of sand particles. The Juminda core shows a consistently low content of mineral matter (LOI < 2%) without clear peaks over the last 8000 years. The LOI results at both Hiiumaa sites show that mineral matter content gradually decreases from 4000 to 1500 cal yrs BP and then becomes the lowest in the period of 1500-1000 cal yrs BP; since then, it becomes higher (up to 10%) with fluctuations and has a clear peak around 700 cal yrs BP. At Saaremaa, the overall trend of mineral matter content is similar to that at the Hiiumaa sites: gradual decline from 2700 to 1500 cal yrs BP, lowest in 1500-1000 cal yrs BP, and relatively high over the last millennium. Concentration of mineral particles reveal clear peaks of aeolian sands at each site. At northern Hiiumaa, concentration has peaks around 3500, 3000 and 2500 cal yrs BP and is relatively high over the last 700 years. At Saaremaa, concentration has peaked at 2100, 1600 and

  15. Vegetation and Climate history of Franz Jozef Land Archipelago in the Late Holocene according pollen data

    Science.gov (United States)

    Nosevich, Ekaterina; Anisimov, Michail; Sapelko, Tatyana

    2015-04-01

    The archipelago Franz-Josef Land is situated in the Arctic Ocean (80°40' N, 54°50'E). It is one of the important areas for arctic research due to organization of Russian Arctic National Park there. Therefore, an interest to the environmental history of this territory grows up and any new data might have a high value. However, geographical remoteness of the archipelago is the reason why there are not much work has been done up to date. .A focus of our researches is vegetation and climate reconstruction during the Late Holocene history according pollen data. In frame of studying of the Franz Josef Land during complex expedition of Russian Arctic National Park on the islands geomorphological and botanical researches was occurred. Nowadays the typical island of archipelago presents the ice cap and glacier-free marine terraces of 35 m high at maximum, where solifluction and permafrost are developed. The archipelago has a maritime Arctic climate. Vegetation of archipelago Franz-Josef Land presents the northern type of Polar Desert. It includes 57 species of vascular plants (Poaceae, Juncaceae, Caryophyllaceae, Brassicaceae, Saxifragaceae etc). We studied the peat core from the southern part of Majbel Island, in the archipelago Franz Josef Land. More than a half of the island is covered by glacier. The core was sampled at the inner margin of ice-free high marine terrace, near the southern slope of bedrock hill. We received preliminary pollen data and radiocarbon data 3010±80 C14 y.a. at the bottom. The pollen concentration is low, but we manage to make some reconstructions of vegetation and climate. For correct interpretation of our results, we used surface samples from different islands of archipelago (Jackson, Hooker, Greely, Alexsandra land, Yeva-Liv, Appolonov, Georg land, Kane, Bell). Subrecent spectra include species presented in flora of region, but also those which are not founded at this region in this time.

  16. PROGRESS IN QUATERNARY AEOLIAN ENVIRONMENT RESEARCH

    Institute of Scientific and Technical Information of China (English)

    LU Rui-jie; CHEN Yuan; HASI Eerdun; YUE Xing-ling

    2005-01-01

    Quaternary aeolian environment researches were mainly conducted by analyzing the information carri-ers, extracting valuable evidences about aeolian environment changes, so to presume and reconstruct paleoenviron-ments. This paper formulated progress in Quaternary aeolian environment research using dune-morphological records,sedimentological records and bio-fossils records, as well as advances about chronology; presented that people shouldpay more attention to further synthetic study of multi-types of records including dune morphology, size, formationtime, sediment supply, and their relations with wind regime in future, especially the research on dating method.

  17. Bursts in intermittent aeolian saltation

    CERN Document Server

    Carneiro, M V; Herrmann, H J

    2014-01-01

    Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of intermittent flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the critical Shields number $\\theta_c$. The time delay between each burst decreases on average with the increase of the Shields number until saltation becomes non-intermittent and the sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain intermittent flux even below the threshold $\\theta_c$ for natural saltation initiation.

  18. Robotic Measurement of Aeolian Processes

    Science.gov (United States)

    Roberts, S.; Duperret, J. M.; Jerolmack, D. J.; Lancaster, N.; Nikolich, G.; Shipley, T. F.; Van Pelt, R. S.; Zobeck, T. M.; Koditschek, D. E.

    2015-12-01

    Local and regional measurements of sand transport and dust emission in complex natural settings presently lack spatiotemporal resolution adequate to inform models relevant for land management, climate policy, and the basic science of geomorphology. Deployments of wind, sand and dust sensors sophisticated enough to begin unpacking the complex relations among wind turbulence, surface roughness, sand flux and dust emission remain largely stationary. Aerial observations from satellites, planes and even UAVs help fill in, but none of these modalities offer the hope of "capturing the action" by being at the right place at the right time relative to the highly localized nature of sediment transport during wind storms. We have been developing a legged robot capable of rapidly traversing desert terrain, and are now adapting it to serve as a platform for scientific instrumentation. We aim to field a semi-autonomous, reactive mobile sensory package suited to the needs of aeolian science that can address the limitations of existing alternatives. This presentation reports on early trials in the Jornada LTER and White Sands National Monument aimed at gathering measurements of airflow and rates of sand transport on a dune face, assessing the role of roughness elements such as vegetation in modifying the wind shear stresses incident on the surface, and estimating erosion susceptibility in a natural arid soil. We will solicit ideas from the audience about other potentially interesting and viable measurement targets. Future close collaboration between aeolian, cognitive and robotics scientists such as we hope to promote through this presentation may yield machines with scientifically relevant sensory suites possessing sufficient autonomy to operate in-situ at the most intense episodes of wind and sediment movement under conditions far too uncomfortable and hazardous for human presence.

  19. Nudibranchia from the remote southern Chilean Guamblin and Ipún islands (Chonos Archipelago, 44-45° S, with re-description of Rostanga pulchra MacFarland, 1905 Nudibranquios de las islas Guamblin e Ipún (Archipiélago de los Chonos 44-45° S con redescripción de Rostanga pulchra MacFarland, 1905

    Directory of Open Access Journals (Sweden)

    MICHAEL SCHRÖDL

    2006-03-01

    Full Text Available The southern Chilean archipelago and fjordland (41-52° S thus far is very poorly investigated also with regard to its nudibranch fauna. This study presents the first records of nudibranchs from remote islands of the Chonos archipelago exposed to the open Pacific. Collecting data and some biological observations are given for the doridoidean Archidoris fontaini, Diaulula punctuolata and Rostanga pulchra. Taxonomically relevant external and radular characters of R. pulchra are redescribed and compared with literature data on conspecifics from Argentina and California. The bipolar, cold-water adapted R. pulchra is critically compared with the western Atlantic, warm-water adapted R. byga. New distributional data indicates that the Chiloé Island area (41-43° S does not represent a strict southern distributional barrier for warm-temperate eastern Pacific nudibranch species but is at least partly due to collecting biasLos archipiélagos y fiordos del sur de Chile han sido muy poco estudiados y particularmente la fauna de nudibranquios. En este estudio se presentan los primeros registros de nudibranquios para islas del Archipiélago de los Chonos abiertas al Pacífico. Se indican datos de recolecta y algunas observaciones biológicas para los doridáceos Archidoris fontaini, Diaulula punctuolata y Rostanga pulchra. La morfología externa y caracteres radulares de R. pulchra son redescritos y comparados con literatura referente a ejemplares de Argentina y California. Se comparan críticamente R. byga de las aguas cálidas del Atlántico occidental con R. pulchra , especie bipolar adaptada a aguas frías. La nueva información distribucional indica que la isla de Chiloé no representa una barrera distribucional estricta para las especies de nudibranquios del Pacífico sudeste, y es en su mayor parte debido a un vacío de recolección

  20. Ecological Risk Source Analysis and the Countermeasures on Functional Islands of Zhoushan Archipelago%基于专家调查问卷法的舟山群岛主体功能岛群生态风险源分析评价与防范对策研究

    Institute of Scientific and Technical Information of China (English)

    李睿; 计丽红; 曹雯婷; 胡春琴

    2016-01-01

    The assessment of island ecological risk is an important premise to develop and manage islands.In this paper,the Zhoushan Archipelago were taken as research area,according to the Ma-jor Function Zoning of Zhoushan City and Zhejiang Province,the Zhoushan archipelago were di-vided into six major functional islands:the Comprehensive Developing Islands,Coastal Tourism Islands,Coastal Industrial Islands,Logistics Islands,Contemporary Fishing Islands and Marine Ecological Islands.Based on expert questionnaire investigation,the main ecological risk sources and hazard degree for the six major functional islands were assessed.The results showed that the top 10 ecological risk sources of the Zhoushan Archipelago are:the typhoon and storm surge,the explosion of petroleum and its products,the oil spilling,the red tides,the landslides and debris flows,the shortage of fresh water resources,the overfishing,the excavation of sand and reef,the biological invasion and the emissions of industrial wastes.According to the extent of potential risk,the six major functional islands are arranged in the following order:the marine ecological is-land,the coastal tourism islands,the contemporary fishing islands,the comprehensive developing islands,the coastal industrial islands and the logistics islands.Some suggestions were also pro-posed in the paper,such as perfecting the controls of different risk sources to improve the perti-nence of disaster prevention and mitigation,improving the construction of public disaster preven-tion infrastructure to prevent common ecological risks.%对海岛进行风险评价是海岛开发利用和保护管理的基础和前提。文章以舟山群岛为研究区域,应用专家调查问卷法,对舟山群岛规划建设中的综合利用岛、滨海旅游岛、临港工业岛、港口物流岛、现代渔业岛、海洋生态岛等不同主体功能岛群面临的主要生态风险源及其危害度进行调查评估。结果表明,接受问卷调查

  1. Energy Transition Initiative: Island Energy Snapshot - U.S. Virgin Islands (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-03-01

    This profile provides a snapshot of the energy landscape of the U.S. Virgin Islands (USVI) - St. Thomas, St. John, and St. Croix. The Virgin Islands archipelago makes up the northern portion of the Lesser Antilles and the western island group of the Leeward Islands, forming the border between the Atlantic Ocean and the Caribbean Sea.

  2. Paleomagnetic Study of Azores Archipelago: Volcano-Tectonic Implications

    Science.gov (United States)

    Silva, P. F.; Henry, B.; Marques, F. O.; Madureira, P.; Miranda, J. M. A.; Lourenco, N. V.; Madeira, J.; Hildenbrand, A.; Nunes, J. C.; Roxerová, Z.

    2014-12-01

    Oceanic islands are by nature unstable volcanic buildings generally marked by rapid growth that alternates with destruction due to a variety of mass-wasting processes, including giant sector collapses, vertical caldera subsidence, fault generation/propagation, shallow landslides and coastal erosion. Due to its diverse volcanic and tectonic frameworks, the Azores archipelago represents an excellent case study for geophysical and geological proposes. Main results of a paleomagnetic study, conducted on oriented samples from approximately 60 accessible lava piles of three islands of Azores archipelago central group (Faial, Pico and Terceira islands) and covering as much as possible spatially and temporally these islands are: i) The paleomagnetic polarity is in close agreement with the radiometric results known for these islands; ii) Onshore volcanic activity began during the Matuyama geochron for Faial and during Brunhes for Terceira and Pico; iii) The mean ChRMs from Terceira and Pico islands result in a paleomagnetic pole similar to the ones retrieved from the studies of Johnson et al (1998) and Silva et al (2012), from S. Miguel and S. Jorge islands (other islands of Azores archipelago), respectively; iv) ChRMs from Faial show an elliptical distribution perpendicular to the WNW-ESE grabben that is the major structure of the island, suggesting tilting towards SSW of the southern wall and towards NNE of the northern one. The presence of listric faults plunging towards the middle of the grabben and aligned along the N110º azimuth could explain the elliptical distribution of paleomagnetic directions. This study is a contribution for the research project REGENA (PTDC/GEO-FIQ/3648/2012). References Johnson, C.L., Wijbrans, J.R., Constable, C.G., Gee, J., Staudigel, H., Tauxe, L., Forjaz, V.-H., Salgueiro, M., 1998. 40Ar/39Ar ages and paleomagnetism of S. Miguel lavas,Azores, Earth planet. Sci. Lett., 160, 637-649. Silva, PF; Henry, B; Marques, FO; Hildenbrand, A

  3. Investigation of the Volcano-tectonic dynamics of Vulcano Island by long-term (40 years) geophysical data

    Science.gov (United States)

    Bonforte, Alessandro; Alparone, Salvatore; Gambino, Salvatore; Guglielmino, Francesco; Obrizzo, Francesco; Velardita, Rosanna

    2015-04-01

    Vulcano island is a composite volcanic edifice located in the south-central sector of the Aeolian Archipelago (Tyrrhenian Sea, Italy). It is the southernmost tip of the southern branch of the Y-shaped archipelago; in particular, it is part of the bigger Lipari-Vulcano volcanic complex that comprises the two southernmost islands of the archipelago. This branch of the archipelago is NNW-SSE oriented and represent the off-shore prolongation of the Tindari-Letojanni tectonic lineament in the NE Sicily, splitting the Appennine chain on the west, from the Calabrian arc on the East. N-S compression seems to affect the western side of this NNW-SSE lineament, while extension affects the eastern one, with active volcanism and a NW dipping Benioff plane. Historic activity at Vulcano has been characterized by frequent transitions from phereatomagmatic to minor magmatic activity. The last eruption in 1888-90 was characterized by energetic explosive pulses and defines the so-called "vulcanian" type of activity. Since then, volcanic activity has taken the form of fumarolic emanations of variable intensity and temperature, mainly concentrated at "La Fossa" crater, with maximum temperatures ranging between 200° and 300° C; temperature increases and changes in the gas chemistry, were often observed. The most recent episode began in the 80's when fumarole temperature progressively increased to 690°C in May 1993. Vulcano is active and this favoured monitoring and research studies, in particular focussed on the most recent structures. In the frame of DPC-INGV "V3" project, we investigate the dynamics of the island through ca. 40 years of ground deformation and seismicity data collected by the discrete and continuous INGV monitoring networks. We considered levelling, GPS, EDM, seismic and tilt data. EDM and levelling measurements began in the middle 1970s and since the late 1990s the same EDM network has been surveyed by GPS. By combining and comparing geodetic data and seismicity we

  4. Ground robotic measurement of aeolian processes

    Science.gov (United States)

    Qian, Feifei; Jerolmack, Douglas; Lancaster, Nicholas; Nikolich, George; Reverdy, Paul; Roberts, Sonia; Shipley, Thomas; Van Pelt, R. Scott; Zobeck, Ted M.; Koditschek, Daniel E.

    2017-08-01

    Models of aeolian processes rely on accurate measurements of the rates of sediment transport by wind, and careful evaluation of the environmental controls of these processes. Existing field approaches typically require intensive, event-based experiments involving dense arrays of instruments. These devices are often cumbersome and logistically difficult to set up and maintain, especially near steep or vegetated dune surfaces. Significant advances in instrumentation are needed to provide the datasets that are required to validate and improve mechanistic models of aeolian sediment transport. Recent advances in robotics show great promise for assisting and amplifying scientists' efforts to increase the spatial and temporal resolution of many environmental measurements governing sediment transport. The emergence of cheap, agile, human-scale robotic platforms endowed with increasingly sophisticated sensor and motor suites opens up the prospect of deploying programmable, reactive sensor payloads across complex terrain in the service of aeolian science. This paper surveys the need and assesses the opportunities and challenges for amassing novel, highly resolved spatiotemporal datasets for aeolian research using partially-automated ground mobility. We review the limitations of existing measurement approaches for aeolian processes, and discuss how they may be transformed by ground-based robotic platforms, using examples from our initial field experiments. We then review how the need to traverse challenging aeolian terrains and simultaneously make high-resolution measurements of critical variables requires enhanced robotic capability. Finally, we conclude with a look to the future, in which robotic platforms may operate with increasing autonomy in harsh conditions. Besides expanding the completeness of terrestrial datasets, bringing ground-based robots to the aeolian research community may lead to unexpected discoveries that generate new hypotheses to expand the science

  5. Returning from the Horizon: Introducing Urban Island Studies

    Directory of Open Access Journals (Sweden)

    Xavier Barceló Pinya

    2015-12-01

    Full Text Available Island studies tends to focus on peripheral, isolated, and marginal aspects of island communities, while urban studies has showed scant awareness of islandness: Although many people research cities on islands, there is little tradition of researching island cities or urban archipelagos per se. Island cities (densely populated small islands and population centres of larger islands and archipelagos nevertheless play import cultural, economic, political, and environmental roles on local, regional, and global scales. Many major cities and ports have developed on small islands, and even villages can fulfil important urban functions on lightly populated islands. Island concepts are also deployed to metaphorically describe developments in urban space. The journal Urban Island Studies explores island and urban processes around the world, taking an island approach to urban research and an urban approach to island research.

  6. Tracer techniques in aeolian research: Approaches, applications, and challenges

    Science.gov (United States)

    Aeolian processes, the entrainment, transport and deposition of sediments by wind, impacts climate, biogeochemical cycles, food security, environmental quality and human health. Considering the multitude of interactions between aeolian processes and all the major components of the Earth system, ther...

  7. THE CHARACTERISTIC OF ISLAND-TYPE TOURISM DESTINATION AND ITS DEVELOPMENT MODE CHOICES—— A CASE STUDY OF ZHOUSHAN ARCHIPELAGO%海岛型旅游目的地的特征及开发模式选择——以舟山群岛为例

    Institute of Scientific and Technical Information of China (English)

    马丽卿

    2011-01-01

    中国海岛资源蕴藏丰富、景观奇特秀丽,是理想的海洋旅游目的地。就目前的开发现状而言,海岛旅游产品类型多样、体验性特色明显、开发热潮初现,但其自然生态脆弱、基础设施落后、开发投资成本较高,目的地成熟程度不高。文章对舟山群岛海洋旅游目的地进行实证分析,归纳出特色主题旅游岛、大旅游产业、城市(镇)旅游化、海岛生态旅游4种单岛型开发模式,区域联动开发和期限性有序开发2种群岛型开发模式,并建议从健全海岛管理体制、发挥社区参与作用、以特色化塑造海岛旅游整体形象、改善海岛旅游交通环境、提升海岛特色旅游产品开发水平五个方面人手,促进我国群岛型旅游地的可持续发展。%China is a country with extensive island resources. It is becoming a new hot issue of marine economy development with protection and exploitation of the islands. The paper analyzes the features of island-type tourism destinations. There are abounding with island resources and rich of the exotic beauty landscapes. That means it's an ideal marine tourism destination. But there is also a shortage of natural environment fragility, poor infrastructure, and high cost of development investment. On the current development situation, island tourism products are varying types and characteristics of significant experimental. But the development boom is just beginning and destination is not mature. This paper has empirical analysis of the marine tourism destination in Zhoushan archipelago. Categorizes six types of development mode, and put forward Island tourism development proposals in China.

  8. Selectivity of terrestrial gastropod extinctions on an oceanic archipelago and insights into the anthropogenic extinction process

    OpenAIRE

    Chiba, Satoshi; Roy, Kaustuv

    2011-01-01

    Anthropogenic impacts have led to widespread extinctions of species on oceanic islands but the nature of many of these extinctions remains poorly known. Here we investigate extinction selectivities of terrestrial gastropods from the Ogasawara archipelago in the northwest Pacific, where anthropogenic threats have changed over time, shifting primarily from the effects of habitat loss to predation by a variety of different predators. Across all of the islands, extinct species had significantly s...

  9. Merging field mapping and numerical simulation to interpret the lithofacies variations from unsteady pyroclastic density currents on uneven terrain: The case of La Fossa di Vulcano (Aeolian Islands, Italy)

    Science.gov (United States)

    Doronzo, Domenico M.; Dellino, Pierfrancesco; Sulpizio, Roberto; Lucchi, Federico

    2017-01-01

    In order to obtain results from computer simulations of explosive volcanic eruptions, one either needs a statistical approach to test a wide range of initial and boundary conditions, or needs using a well-constrained field case study via stratigraphy. Here we followed the second approach, using data obtained from field mapping of the Grotta dei Palizzi 2 pyroclastic deposits (Vulcano Island, Italy) as input for numerical modeling. This case study deals with impulsive phreatomagmatic explosions of La Fossa Cone that generated ash-rich pyroclastic density currents, interacting with the topographic high of the La Fossa Caldera rim. One of the simplifications in dealing with well-sorted ash (one particle size in the model) is to highlight the topographic effects on the same pyroclastic material in an unsteady current. We demonstrate that by merging field data with 3D numerical simulation results it is possible to see key details of the dynamical current-terrain interaction, and to interpret the lithofacies variations of the associated deposits as a function of topography-induced sedimentation (settling) rate. Results suggest that a value of the sedimentation rate lower than 5 kg/m2 s at the bed load can still be sheared by the overlying current, producing tractional structures (laminae) in the deposits. Instead, a sedimentation rate higher than that threshold can preclude the formation of tractional structures, producing thicker massive deposits. We think that the approach used in this study could be applied to other case studies (both for active and ancient volcanoes) to confirm or refine such threshold value of the sedimentation rate, which is to be considered as an upper value as for the limitations of the numerical model.

  10. 'Redefining health care': medical homes or archipelagos to navigate?

    Science.gov (United States)

    Enthoven, Alain C; Crosson, Francis J; Shortell, Stephen M

    2007-01-01

    This paper provides an analysis of the structure of the health care delivery system, emphasizing physician group practices. The authors argue for comprehensive integrated delivery systems (IDSs). The jumping-off point for their analysis is the recently published Redefining Health Care: Creating Value-Based Competition on Results, by Michael Porter and Elizabeth Teisberg. The authors focus on the book's core idea that competitors should be freestanding integrated practice units (or "islands in archipelagos") versus IDSs (or "medical homes"). In any case, the authors contend that this issue should be resolved by competition to attract and serve informed, cost-conscious, responsible consumers on a level playing field.

  11. DPTM simulation of aeolian sand ripple

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Aeolian sand ripple and its time evolution are simulated by the discrete particle tracing method (DPTM) presented in this paper. The difference between this method and the current methods is that the former can consider the three main factors relevant to the formation of natural aeolian sand ripples,which are the wind-blown sand flux above the sand bed formed by lots of sand particles with different di-ameters,the particle-bed collision and after it the rebound and ejection of sand particles in the sand bed,the saltation of high-speed sand particles and the creep of low-speed sand particles,respectively. The simulated aeolian sand ripple is close to the natural sand ripple not only in basic shape and characteristic,particle size segregation and stratigraphy,but also in formation stages. In addition,three important speeds can be obtained by this method,which are the propagation speed of the saturated aeolian sand ripple and the critical frictional wind speeds of emergence and disappearance of sand ripple.

  12. DPTM simulation of aeolian sand ripple

    Institute of Scientific and Technical Information of China (English)

    ZHENG XiaoJing; BO TianLi; XIE Li

    2008-01-01

    Aeolian sand ripple and its time evolution are simulated by the discrete particle tracing method (DPTM) presented in this paper.The difference between this method and the current methods is that the former can consider the three main factors relevant to the formation of natural aeolian sand ripples, which are the wind-blown sand flux above the sand bed formed by lots of sand particles with different di-ameters, the particle-bed collision and after it the rebound and ejection of sand particles in the sand bed, the saltation of high-speed sand particles and the creep of low-speed sand particles, respectively.The simulated aeolian sand ripple is close to the natural sand ripple not only in basic shape and characteristic, particle size segregation and stratigraphy, but also in formation stages.In addition, three important speeds can be obtained by this method, which are the propagation speed of the saturated aeolian sand ripple and the critical frictional wind speeds of emergence and disappearance of sand ripple.

  13. On the mathematical modeling of aeolian saltation

    DEFF Research Database (Denmark)

    Jensen, Jens Ledet; Sørensen, Michael

    1983-01-01

    The development of a mathematical model for aeolian saltation is a promising way of obtaining further progress in the field of wind-blown sand. Interesting quantities can be calculated from a model defined in general terms, and a specific model is defined and compared to previously published data...

  14. High precision locations of long-period events at La Fossa Crater (Vulcano Island, Italy

    Directory of Open Access Journals (Sweden)

    Salvatore Rapisarda

    2009-06-01

    Full Text Available Since the last eruption in 1888-90, the volcanic activity on Vulcano Island (Aeolian Archipelago, Italy has been limited to fumarolic degassing. Fumaroles are mainly concentred at the active cone of La Fossa in the northern sector of the island and are periodically characterized by increases in temperature as well as in the amount of both CO2 and He. Seismic background activity at Vulcano is dominated by micro-seismicity originating at shallow depth (<1-1.5 km under La Fossa cone. This seismicity is related to geothermal system processes and comprises long period (LP events. LPs are generally considered as the resonance of a fluid-filled volume in response to a trigger. We analyzed LP events recorded during an anomalous degassing period (August-October 2006 applying a high precision technique to define the shape of the trigger source. Absolute and high precision locations suggest that LP events recorded at Vulcano during 2006 were produced by a shallow focal zone ca. 200 m long, 40 m wide and N30-40E oriented. Their occurrence is linked to magmatic fluid inputs that by modifying the hydrothermal system cause excitation of a fluid-filled cavity.

  15. Aeolian Processes at Meridiani Planum

    Science.gov (United States)

    Watters, W. A.; Fike, D. A.; Greeley, R.; Grotzinger, J. P.; Jerolmack, D. J.; Malin, M. C.; Soderblom, L.; Squyres, S.; Sullivan, R.; Thompson, S.

    2004-12-01

    The Opportunity Rover has observed a variety of aeolian features at Meridiani Planum. These features imply wind-related processes that operate on a range of time-scales, so that at least a relative time-scale of formation and modification can be assigned to many. (a) Features forming and changing in the shortest time include probable impact ripples (cm-scale) that occur in dark basalt sand on the floors of local depressions throughout the plains. Also in this category are deposits of bright airfall dust (in the form of streaks) that are not removed downwind of topographic features such as crater rims. Analysis of MOC imagery indicates that streaks change orientation after intense dust storms. The similar orientations of impact ripples and bright streaks are thought to indicate the prevailing direction of the most-recent vigorous wind regime. (b) Forming and changing on a longer, intermediate time-scale (and hence older) are deflationary ripples armored with well-sorted mm-sized hematitic grains that likely propagate by creep (i.e., pushed by the impacts of smaller saltating grains). The removal of dust from the plains during storms implies saltation of sand ( ˜ 100 μ m) which indicates shear velocities approaching what is required to roll the ˜ 1 mm hematitic grains. The ``plains ripples'' rarely occupy local depressions and cover the plains at Meridiani Planum ( ˜ 1 cm tall, ˜ 10 cm wide, up to ˜ 1 m long). Plains ripples indicate two prominent orientations: the orientation of individual bedforms as well as that of en-echelon ripple trains. As deflationary structures that form by the winnowing of small grains, these features require relatively long periods to form. The presence of multiple orientations indicates that, once formed, multiple episodes of vigorous winds may be required to change markedly the orientations of these features. (c) Requiring probably the longest formation times are tails of protected rock downwind of hematite spherules embedded in

  16. Depth Contours for select locations across the U.S. Pacific Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are depth contours (isobaths) derived at 50 meters for most islands and reefs in the Mariana Archipelago, American Samoa, and the Pacific Remote Island...

  17. Chronology and stratigraphy of the Magdalen Islands archipelago from the last glaciation to the early Holocene: new insights into the glacial and sea-level history of eastern Canada

    DEFF Research Database (Denmark)

    Rémillard, Audrey M.; St-Onge, Guillaume; Bernatchez, Pascal

    2016-01-01

    The Magdalen Islands (Québec, Canada) are a key location for unravelling the glacial and sea-level history of the Maritime Provinces of eastern Canada. Although many sedimentary sequences have been described in the literature, absolute ages are lacking, impeding an accurate interpretation of the ...

  18. Tropical storm off Myanmar coast sweeps reefs in Ritchie's Archipelago, Andaman

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnan, P.; Grinson-George, G.; Vikas, N.; Titus-Immanuel, T.; Goutham-Bharathi, M.P.; Anand, A.; VinodKumar, K.; SenthilKumar, S.

    Archipelago; Red Skin Island (11° 32' 23.27” N 92° 35' 03.98” E), a popular tourist site under Mahatma Gandhi Marine National Park; North Bay (11° 42' 21.20” N 92° 45' 15.20” E) and Chidiya- tapu (11° 29' 28.00” N 92° 42' 40.00” E), sites in Port Blair which... at Rit- chie’s Archipelago; (1) South Button Island; (2) Sebastian hill; (3) Minerva ledge; (4) Broken ledge; (5) Jackson bar; (6) Red Skin; (7) North Bay; (8) Chidya- tapu. b Specific locations surveyed around South But- ton Island Environ Monit Assess...

  19. New insights on the petrology of submarine volcanics from the Western Pontine Archipelago (Tyrrhenian Sea, Italy)

    Science.gov (United States)

    Conte, A. M.; Perinelli, C.; Bianchini, G.; Natali, C.; Martorelli, E.; Chiocci, F. L.

    2016-11-01

    The Pontine Islands form a volcanic archipelago in the Tyrrhenian Sea. It consists of two edifices, the islands of Ponza, Palmarola and Zannone and the islands of Ventotene and Santo Stefano, respectively. The Archipelago developed during two main volcanic cycles in the Plio-Pleistocene: 1) the Pliocene episode erupted subalkaline, silica-rich volcanic units, which constitute the dominant products in the western edifice (Ponza and Zannone Islands); 2) the Pleistocene episode erupted more alkaline products, represented by evolved rocks (trachytes to peralkaline rhyolites) in the islands of Ponza and Palmarola and by basic to intermediate rocks in the eastern edifice (Ventotene and Santo Stefano Islands). In this paper we present new geochemical and petrological data from submarine rock samples collected in two oceanographic cruises and a scuba diving survey. The main result is the recovery of relatively undifferentiated lithotypes that provide further insights on the magmatic spectrum existing in the Pontine Archipelago, allowing modelling of the whole suite of rocks by fractional crystallization processes. New major and trace element data and thermodynamic constrains (by the software PELE) indicate the existence of three distinct evolutionary trends corresponding to a HK calcalkaline series in the Pliocene, followed by a transitional and then by a shoshonite series in the Pleistocene. In particular, the transitional series, so far overlooked in the literature, is required in order to explain the genesis of several peralkaline felsic rocks recognized in the Archipelago. On the whole, the new geochemical data i) confirm the orogenic signature of the suites, ii) allow to rule out an anatectic origin for both subalkaline and peralkaline rhyolites and iii) indicate highly heterogeneous mantle sources, due to crustal components variously recycled in the mantle via subduction.

  20. Historical tsunami in the Azores archipelago (Portugal)

    Science.gov (United States)

    Andrade, C.; Borges, P.; Freitas, M. C.

    2006-08-01

    Because of its exposed northern mid-Atlantic location, morphology and plate-tectonics setting, the Azores Archipelago is highly vulnerable to tsunami hazards associated with landslides and seismic or volcanic triggers, local or distal. Critical examination of available data - written accounts and geologic evidence - indicates that, since the settlement of the archipelago in the 15th century, at least 23 tsunami have struck Azorean coastal zones. Most of the recorded tsunami are generated by earthquakes. The highest known run-up (11-15 m) was recorded on 1 November 1755 at Terceira Island, corresponding to an event of intensity VII-VIII (damaging-heavily damaging) on the Papadopolous-Imamura scale. To date, eruptive activity, while relatively frequent in the Azores, does not appear to have generated destructive tsunami. However, this apparent paucity of volcanogenic tsunami in the historical record may be misleading because of limited instrumental and documentary data, and small source-volumes released during historical eruptions. The latter are in contrast with the geological record of massive pyroclastic flows and caldera explosions with potential to generate high-magnitude tsunami, predating settlement. In addition, limited evidence suggests that submarine landslides from unstable volcano flanks may have also triggered some damaging tsunamigenic floods that perhaps were erroneously attributed to intense storms. The lack of destructive tsunami since the mid-18th century has led to governmental complacency and public disinterest in the Azores, as demonstrated by the fact that existing emergency regulations concerning seismic events in the Azores Autonomous Region make no mention of tsunami and their attendant hazards. We suspect that the coastal fringe of the Azores may well preserve a sedimentary record of some past tsunamigenic flooding events. Geological field studies must be accelerated to expand the existing database to include prehistoric events

  1. Reading the Planetary Archipelago of the Torres Strait

    Directory of Open Access Journals (Sweden)

    Elizabeth McMahon

    2013-05-01

    Full Text Available This essay makes use of the Western concept of the archipelago as a starting point for an examination of island to island relations in the Torres Strait, Australia, as they are rehearsed in the imaginary domain of story, in both its written and oral modes. The essay deploys Spivak’s notions of planetarity and Bloch’s concept of utopianism as ways of charting the relationship between two Torres Strait stories, one old, one new. In so doing, the essay seeks to identify the capacity of Torres Strait literature and storytelling to re-conceive relations of space and time and to acknowledge a spatial and temporal mobility running parallel to the circumscribed trajectories of late modernity.

  2. Progressive migration and anagenesis in Drimys confertifolia of the Juan Fernández Archipelago, Chile.

    Science.gov (United States)

    López-Sepúlveda, Patricio; Takayama, Koji; Greimler, Josef; Crawford, Daniel J; Peñailillo, Patricio; Baeza, Marcelo; Ruiz, Eduardo; Kohl, Gudrun; Tremetsberger, Karin; Gatica, Alejandro; Letelier, Luis; Novoa, Patricio; Novak, Johannes; Stuessy, Tod F

    2015-01-01

    A common mode of speciation in oceanic islands is by anagenesis, wherein an immigrant arrives and through time transforms by mutation, recombination, and drift into a morphologically and genetically distinct species, with the new species accumulating a high level of genetic diversity. We investigate speciation in Drimys confertifolia, endemic to the two major islands of the Juan Fernández Archipelago, Chile, to determine genetic consequences of anagenesis, to examine relationships among populations of D. confertifolia and the continental species D. winteri and D. andina, and to test probable migration routes between the major islands. Population genetic analyses were conducted using AFLPs and nuclear microsatellites of 421 individuals from 42 populations from the Juan Fernández islands and the continent. Drimys confertifolia shows a wide genetic variation within populations on both islands, and values of genetic diversity within populations are similar to those found within populations of the continental progenitor. The genetic results are compatible with the hypothesis of high levels of genetic variation accumulating within anagenetically derived species in oceanic islands, and with the concept of little or no geographical partitioning of this variation over the landscape. Analysis of the probability of migration within the archipelago confirms colonization from the older island, Robinson Crusoe, to the younger island Alejandro Selkirk.

  3. Divergence and long-distance overseas dispersals of island populations of the Ryukyu five-lined skink, Plestiodon marginatus (Scincidae: Squamata), in the Ryukyu Archipelago, Japan, as revealed by mitochondrial DNA phylogeography.

    Science.gov (United States)

    Kurita, Kazuki; Hikida, Tsutomu

    2014-04-01

    We assessed the historical biogeography of the Ryukyu five-lined skink, Plestiodon marginatus, and related species (P. stimpsonii and P. elegans). Our specific aims were to reveal the origin, tim- ing, and route of the colonization to three volcanic islands in the northern Tokara Group of the northern Ryukyus: Kuchinoshima, Nakanoshima, and Suwanosejima. We conducted phylogenetic analyses and divergence time estimation using a partial sequence of the mitochondrial cytochrome b gene for P. marginatus collected from across its whole range (the northern and central Ryukyus), and for P. stimpsonii (from the Yaeyama Group of the southern Ryukyus) and P. elegans (from Taiwan). Our results suggest three major clades (A, B, and C). Clades A and B consist of P. marginatus, excluding the Kuchinoshima population, and Clade C consisted of the Kuchinoshima population, P. stimpsonii, and P. elegans. These clades are estimated to have diverged during the Late Miocene to the Late Pliocene. Among the three examined northern Tokara populations, the Kuchinoshima population was shown to be a sister group of P. stimpsonii. The two other populations from Nakanoshima and Suwanosejima Islands were closely related to P. marginatus from the northern part of the Okinawa Group and that from Kodakarajima Island in the southern Tokara Group, respectively. These populations are estimated to have diverged from their respective related spe cies in various ages of the Early to Late Pleistocene, suggesting that they colonized the islands by independent overseas dispersals of approximately 50-850 km via the Kuroshio Current. Taxonomic implications for P. marginatus are also discussed.

  4. Introducing a New International Society of Aeolian Research

    Science.gov (United States)

    Zobeck, T. M.; Lee, J.; Lancaster, N.; Bullard, J. E.

    2008-12-01

    Aeolian research is a long-standing and rapidly growing area of geological study where scientists of many disciplines meet to investigate the effects of wind on the surface of the Earth and other planetary bodies such as Mars and Titan. Fields of study in aeolian research cover a broad spectrum ranging from developing a basic scientific understanding of the fundamental physical processes of grain motion to the effects of soil erosion on landscape health and environmental sustainability. Aeolian research also includes studies of the effects of aeolian particles on global climate, air quality, and human health, coastal sand transport processes, land degradation, dune migration, the formation of sand seas, and much more. A growing number of international conferences have been organized to focus specifically on aeolian phenomena and a vast number of scholarly publications have been produced to support the science. One popular bibliography includes over 30,000 citations and hundreds of peer-reviewed papers are published each year. Until very recently, no scientific society specifically dealing with aeolian research has been available. The new International Society of Aeolian Research (ISAR) that has been organized to bring together aeolian scientists from around the world. The new society was created to promote contacts among researchers in aeolian processes and related subjects for discussion and comparison of research, to initiate conferences (such as the International Conference on Aeolian Research), to organize excursions, and support the publication of a peer-reviewed scientific journal. The International Society of Aeolian Research sponsors the new Elsevier journal Aeolian Research in support of these activities. This paper will provide further details about the new society and the journal. Please see www.aeolianresearch.org for details.

  5. Aesthetic value of aeolian geomorphosites in the Kumtagh Desert, China

    Institute of Scientific and Technical Information of China (English)

    JinFeng Wu; Xin Wang; Feng Guo; Lei Li

    2014-01-01

    Tourism development of aeolian geomorphosites in the Kumtagh Desert is beneficial to both harmonious development of human-nature relationship and the sustainable development of the tourist industry in the Kumtagh Desert and its sur-rounding area. This paper adopts some research methods including field observation, expert assessment, and systematic investigation to analyze and evaluate the aesthetic value of aeolian geomorphosites in the Kumtagh Desert from three aspects of"Beauty of Morphology","Beauty of Color"and"Beauty of Forms". This research is a creative work in the field of aeolian geomorphosites combining the method of aeolian geomorphology and tourism geography.

  6. Feedbacks between aeolian processes and ecosystem change in a degraded desert grassland in the southwestern US

    Science.gov (United States)

    Li, Junran

    2015-04-01

    The desert grassland in the southwestern US has undergone dramatic vegetation changes with many areas of grassland becoming shrublands in the last 150 years. A principle manifestation of such a land degradation is the wide distribution of fertile islands in once-homogenous landscapes, which changed soil resource redistributions through the movement of resources from plant interspaces to the area beneath plant canopies. A great deal of work has examined the role of water in nutrient reduction and enforcement of islands of fertility in the semiarid landscapes. However, little is known on the role of wind in the removal or redistribution of soil resources, and further the feedbacks between wind and ecosystem change in this area. In spring 2004, a vegetation removal experiment was established in the northern Chihuahuan Desert, southern New Mexico, where vegetation cover on the experimental plots were manually reduced to various levels to study the entire suite of aeolian processes, including erosion, transport, and deposition in creating and enforcing patchy distribution of vegetation. This experiment has been continually maintained for more than ten years, with the sampling and observation of vegetation cover, soil nutrients, sediment flux, topography, and plant physiology. The experimental results highlighted that the aeolian processes in the Chihuahuan Desert are able to change soil properties and community composition in as short as 3 three years. Further, the removal of grasses by 75% may trigger a very substantial increase of wind erosion and the removal of grass by 50% could cause significant amount of C and N loss due to wind erosion. Last but not least, the change of the spatial distribution of soil C and the micro-topography both point to the fact that aeolian processes contribute substantially to the dynamics of fertile islands in this desert grassland.

  7. Rare sulfosalts from vulcano, aeolian islands, Italy

    DEFF Research Database (Denmark)

    Pinto, Daniela; Balic Zunic, Tonci; Bonaccorsi, Elena

    2006-01-01

    the a and b unit-cell parameters, which increase with the increase of the Cl content. The structural refinements converge to the agreement R values of 3.10 % for 840 reflections [Fo > 4s(Fo)] and 1.49 % for 376 reflections [Fo > 4s(Fo)], respectively. The structure of Cl-bearing galenobismutite...... is topologically identical to that of Cl-free galenobismutite. The excess of Pb observed in Cl-bearing galenobismutite is incorporated in the trigonal prismatic M2gb and M3gb sites. No Pb for Bi substitution was observed for the octahedral position M1gb. No evidence of a preferential distribution of Cl among...

  8. The water landscapes of the Canary Islands

    DEFF Research Database (Denmark)

    Lee, Gini; Braae, Ellen Marie; Diedrich, Lisa

    2013-01-01

    Island environments, particularly small archipelagos such as the Canary Islands, are more visible subject to the vagaries of change wrought by ecological and climate dynamics, shifting social conditions and economic impacts subject to global markets, than is witnessed on continental worlds....

  9. The water landscapes of the Canary Islands

    DEFF Research Database (Denmark)

    Lee, Gini; Braae, Ellen Marie; Diedrich, Lisa

    2013-01-01

    Island environments, particularly small archipelagos such as the Canary Islands, are more visible subject to the vagaries of change wrought by ecological and climate dynamics, shifting social conditions and economic impacts subject to global markets, than is witnessed on continental worlds....

  10. Diversity of fruit-feeding butterflies in a mountaintop archipelago of rainforest.

    Science.gov (United States)

    Pereira, Geanne Carla Novais; Coelho, Marcel Serra; Beirão, Marina do Vale; Braga, Rodrigo Fagundes; Fernandes, Geraldo Wilson

    2017-01-01

    We provide the first description of the effects of local vegetation and landscape structure on the fruit-feeding butterfly community of a natural archipelago of montane rainforest islands in the Serra do Espinhaço, southeastern Brazil. Butterflies were collected with bait traps in eleven forest islands through both dry and rainy seasons for two consecutive years. The influence of local and landscape parameters and seasonality on butterfly species richness, abundance and composition were analyzed. We also examined the partitioning and decomposition of temporal and spatial beta diversity. Five hundred and twelve fruit-feeding butterflies belonging to thirty-four species were recorded. Butterfly species richness and abundance were higher on islands with greater canopy openness in the dry season. On the other hand, islands with greater understory coverage hosted higher species richness in the rainy season. Instead, the butterfly species richness was higher with lower understory coverage in the dry season. Butterfly abundance was not influenced by understory cover. The landscape metrics of area and isolation had no effect on species richness and abundance. The composition of butterfly communities in the forest islands was not randomly structured. The butterfly communities were dependent on local and landscape effects, and the mechanism of turnover was the main source of variation in β diversity. The preservation of this mountain rainforest island complex is vital for the maintenance of fruit-feeding butterfly community; one island does not reflect the diversity found in the whole archipelago.

  11. White Sea Islands: contemporary relief dynamics and history of the development.

    Science.gov (United States)

    Kosevich, N.

    2012-04-01

    The fundamental problem of isolated areas of land relief formation that created and changed by the interaction of both continental and oceanic natural processes. The main objective is to reveal the main geomorphological features of islands and their development tendencies, to reconstruct the late Pleistocene and Holocene formation history, and to systematize the present ideas according to integrated geomorphological approach. The main objects of study are so called «small» islands with the areas not exceeding few hundred square kilometers. A small land area, surrounded by water, is a good model that allows to visualize the results of interaction between endogenous and exogenous factors and relief formation conditions (continental and oceanic). Relationship between conditions, factors and processes of relief formation on islands are extremely complex, variable and ambiguous. A small island gives an opportunity to trace the initial stages of land origin, the first stages of subaerial relief development, and in general - the first steps of nature evolution after its emergence from the ocean. Therefore, their integrated study is an important fundamental problem in modern science. Our preliminary studies included: • Analysis of existing information on the White Sea islands relief. • Elaboration of the geological and geomorphologic array concept based on remotely sensed data. • Typify the islands using compiled data sets. • Large-scale mapping of geomorphologic and morpho-structural peculiarities of islands and/or island groups and allocation of the key model territories. The present field studies include: 1. Geomorphologic survey of the selected areas. 2. Drilling and sinking of prospect-holes of lacustrine-swamp, alluvial, marine, aeolian, and other deposits with sampling for further analysis (diatom, lithologic, etc.) to determine the conditions of sediments formation. Particular attention is paid to identification and sampling of carbon containing material

  12. New species of Xestoleberididae (Crustacea, Ostracoda from Archipelago of São Pedro and São Paulo, Equatorial Atlantic

    Directory of Open Access Journals (Sweden)

    Nathália C. da Luz

    2014-12-01

    Full Text Available Two new species of Xestoleberididae: Xestoleberis brasilinsularis sp. nov. and Xestoleberis machadoae sp. nov., both endemic to Archipelago of São Pedro and São Paulo, are described. The record of these shallow marine waters species from Brazilian oceanic islands represents an important contribution to the knowledge of the evolutionary history the species inhabit areas.

  13. The blowflies of the Madeira Archipelago: species diversity, distribution and identification (Diptera, Calliphoridae s. l.)

    Science.gov (United States)

    Prado e Castro, Catarina; Szpila, Krzysztof; Martínez-Sánchez, Anabel; Rego; Silva, Isamberto; Serrano, Artur R.M.; Boieiro, Mário

    2016-01-01

    Abstract Knowledge on the taxonomic diversity and distribution of blowflies from the Madeira Archipelago is updated. New and interesting findings are reported for poorly studied islands and islets of this archipelago, together with a brief analysis of the diversity of Macaronesian Calliphoridae s. l. Seven blowfly species were collected during this study, including the first records of Calliphora vicina Robineau-Desvoidy, 1830, Chrysomya albiceps (Wiedemann, 1819), Lucilia sericata (Meigen, 1826), Pollenia rudis (Fabricius, 1794) and Stomorhina lunata (Fabricius, 1805) from Porto Santo, and of Calliphora vicina, Lucilia sericata and Stomorhina lunata from Desertas Islands. The presence of Calliphora loewi Enderlein, 1903 in Madeira Laurisilva forest is discussed and its first instar larva is redescribed, revealing important differences in relation to its original description. An identification key to the adult Madeiran blowflies is provided for the first time. PMID:27917052

  14. Recent Aeolian Dune Change on Mars

    Science.gov (United States)

    Bourke, M. C.; Edgett, K. S.; Cantor, B. A.

    2007-01-01

    Previous comparisons of Martian aeolian dunes in satellite images have not detected any change in dune form or position. Here, we show dome dunes in the north polar region that shrank and then disappeared over a period of 3.04 Mars years (5.7 Earth years), while larger, neighboring dunes showed no erosion or movement. The removal of sand from these dunes indicates that not only is the threshold wind speed for saltation exceeded under present conditions on Mars, but that any sand that is available for transport is likely to be moved. Dunes that show no evidence of change could be crusted, indurated. or subject to infrequent episodes of movement.

  15. Archaen to Recent aeolian sand systems and their sedimentary record

    DEFF Research Database (Denmark)

    Rodríguez-López, Juan Pedro; Clemmensen, Lars B; Lancaster, Nick

    2014-01-01

    The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand-sea or dunefield (erg) deposits, whereas coastal systems...... are primarily known from the Cenozoic. The complexity of aeolian sedimentary processes and facies variability are under-represented and excessively simplified in current facies models, which are not sufficiently refined to reliably account for the complexity inherent in bedform morphology and migratory...... behaviour, and therefore cannot be used to consistently account for and predict the nature of the preserved sedimentary record in terms of formative processes. Archean and Neoproterozoic aeolian successions remain poorly constrained. Palaeozoic ergs developed and accumulated in relation...

  16. New paleomagnetic data from late Paleozoic sedimentary rocks of Novaya Zemlya Archipelago: tectonic implications

    Science.gov (United States)

    Abashev, Victor V.; Metelkin, Dmitry V.; Mikhaltsov, Nikolay E.; Vernikovsky, Valery A.; Matushkin, Nikolay Yu.

    2017-04-01

    New paleomagnetic data for Novaya Zemlya archipelago were obtained by processing the samples collection gathered during the 2014 field season. The paleomagnetic directions and paleomagnetic poles were determined from the Paleozoic sedimentary complexes located on the Southern Island (Upper Permian) and the Northern Island (Lower and Upper Devonian, Upper Carboniferous) of the archipelago. Positive fold and reversal tests indicate that the isolated paleomagnetic directions correspond to the primary magnetization components. The corresponding paleomagnetic pole are in good agreement with poles obtained earlier in the 1980s by E.L. Gurevich and I.A. Pogarskaya. Considering the confidence ovals, the paleomagnetic poles obtained for the sites of the Northern Island are located close to the corresponding path segment of the APWP of Europe. This means that at least since the early Devonian, the northern part of Novaya Zemlya Archipelago had a position that was close to its current position relatively to the Arctic margin of Europe and has not undergone significant shifts or rotations. However, the upper Permian paleomagnetic pole for the Southern Island is very different from the corresponding part of the European APWP. We are considering this pole position within a model, involving significant intraplate movement between the structures of the European and Siberian tectonic provinces until the Late Cretaceous. The sinistral strike-slips inferred by the model could have caused or were accompanying the opening of the Mesozoic rift system in Western Siberia. This event has reached its maximum within the South Kara basin and resulted in the north-westward (in geographic coordinates) displacement of the southern part of the Novaya Zemlya Archipelago in relation to the Arctic margin of Europe and in the deformation of the Pay-Khoy-Novaya Zemlya margin, which caused its modern curved form. The study was supported by the Russian Science Foundation, grant No. 14-37-00030 and the

  17. Number of endemic and native plant species in the Galapagos Archipelago in relation to geographical parameters

    DEFF Research Database (Denmark)

    Willerslev, E.; Hansen, Anders J.; Nielsen, K. K.

    2002-01-01

    By simple and multiple regression analyses we investigate updated species numbers of endemic and native vascular plants and seed plants in the Galapagos Archipelago in relation to geographical parameters. We find that the best models to describe species numbers are regression models with log...... explained variation is in general small. The results show that the species area relationships are different for native and endemic species. This is discussed in relation to classical island biogeographical models, and the concepts of radiative speciation. Udgivelsesdato: 2002...

  18. Description of Nicrophorus efferens, new species, from Bougainville Island (Coleoptera, Silphidae, Nicrophorinae

    Directory of Open Access Journals (Sweden)

    Derek Sikes

    2013-06-01

    Full Text Available A new species of Nicrophorus in the nepalensis species-group, Nicrophorus efferens Sikes and Mousseau, is described from Bougainville Island in the Solomon Islands archipelago. It is distinguished from the known species of the genus Nicrophorus and its likely closest relative, Nicrophorus reticulatus Sikes and Madge, based on external morphology. A comparison among the four Nicrophorus species known from the Solomon Island archipelago and Papua New Guinea is presented.

  19. The scale insects (Hemiptera: Coccoidea) of the Maltese Archipelago.

    Science.gov (United States)

    Mifsud, David; Mazzeo, Gaetana; Russo, Agatino; Watson, Gillian W

    2014-09-25

    Past works on scale insects (Hemiptera: Coccoidea) from the Maltese Archipelago are reviewed. Based on the literature and contemporary collections, a total of 93 species of scale insects belonging to 12 scale insect families are here reported (Aclerdidae 1 species; Asterolecaniidae 4; Coccidae 17; Diaspididae 46; Eriococcidae 5; Kermesidae 1; Margarodidae 1; Micrococcidae 1; Monophlebidae 2; Pseudoccocidae 11; Putoidae 2 and Rhizoecidae 2). Of these, 17 species represent new distribution records. Ten species are excluded from the scale insect fauna of the Maltese Islands. Of the 93 species present, only 29 (31.18%) are probably indigenous and the rest (68.82%) represent established introductions from elsewhere. More than 65% of the indigenous species are typical Mediterranean in distribution, with a few species having a mainly European chorotype. A quarter of the established aliens originate from Eurasia, followed by an East Asian/ Oriental component (20.31%); European (14.06%); Neotropical (14.06%); cryptogenic (14.06%); African (7.81%) and Australasian (4.70%). Movement of live fruit trees and ornamental plants into the Maltese Archipelago from nearby countries is probably the main route for entry of alien scale insects into the country. Some possible future introductions are discussed.

  20. Large mainland populations of South Island robins retain greater genetic diversity than offshore island refuges

    NARCIS (Netherlands)

    Boessenkool, Sanne; Taylor, Sabrina S.; Tepolt, Carolyn K.; Komdeur, Jan; Jamieson, Ian G.

    2007-01-01

    For conservation purposes islands are considered safe refuges for many species, particularly in regions where introduced predators form a major threat to the native fauna, but island populations are also known to possess low levels of genetic diversity. The New Zealand archipelago provides an ideal

  1. Stygofauna of the Canary Islands, 9. The amphipod genus Pseudoniphargus (Crustacea) in the Canary Islands

    NARCIS (Netherlands)

    Stock, Jan H.

    1988-01-01

    Pseudoniphargus was known from inland stygohabitats in the Iberian peninsula, the Azores, Madeira, N.W. Africa, and Bermuda, but not from the Canary Islands. Systematic sampling in six of the seven larger islands of the latter archipelago has revealed the presence of the genus in Tenerife (4 species

  2. Volcanological implications of crystal-chemical variations in clinopyroxenes from the Aeolian Arc, Southern Tyrrhenian Sea (Italy)

    Science.gov (United States)

    Nazzareni, Sabrina; Molin, Gianmario; Peccerillo, Angelo; Zanazzi, Pier Francesco

    2001-03-01

    Crystal chemistry and structural data for clinopyroxene from the Aeolian islands (Southern Tyrrhenian Sea, Italy) were determined with the aim of obtaining geobarometric information and exploring implications for the structure of volcanic plumbing systems. Cell and M1 site volumes for clinopyroxenes, which are known to decrease with increasing pressure of crystallization, revealed variable values, both within some single islands and along the entire arc, indicating polybaric conditions of crystallization. The lowest cell and M1 volumes were found at Filicudi, plotting close to values of clinopyroxenes from high-pressure ultramafic xenoliths entrained in alkali basalts. Indications of high-pressure crystallization were also found at Salina and, to a lesser extent, at Alicudi, all situated in the western sector of the Aeolian Arc. The central and eastern islands of Lipari, Vulcano, Panarea and Stromboli generally show higher values of cell parameters, suggesting crystallization in shallow magma chambers. These islands are characterized by the occurrence of large calderas, which are apparently lacking at Salina and Filicudi. Time-related variations were observed for cell and M1 volumes of clinopyroxene for some islands. At Salina, the early-erupted products display low values of cell parameters with respect to later activity, thus indicating a decrease in crystallization pressure with time. A similar, although less striking, pattern is observed at Alicudi and Lipari. An overall increase in cell parameters with time was observed at the scale of the entire arc. The observed variations in clinopyroxene structural parameters highlight the significance of pyroxene crystal chemistry for petrogenetic and volcanological interpretation. Correlation with time and the structural characteristics of volcanoes suggest significant regional and temporal modifications in the plumbing systems of Aeolian volcanoes. Clinopyroxenes from Filicudi and the older Salina crystallized at high

  3. The coastal fishes and fisheries of the Socotra Archipelago, Yemen.

    Science.gov (United States)

    Zajonz, Uwe; Lavergne, Edouard; Klaus, Rebecca; Krupp, Friedhelm; Aideed, Moteah Sheikh; Saeed, Fouad Naseeb

    2016-04-30

    The Socotra Archipelago is situated in the Gulf of Aden where tropical and "pseudo-temperate" conditions combine to create a unique marine ecosystem. The diversity, ecology, productivity and fisheries of the coastal fish assemblages are still relatively understudied and no update of the scientific knowledge existed. The islands support unique coastal and coral-associated fish assemblages in spite of the limited biogenic reef frameworks. Fish diversity is the highest among comparable Arabian eco-regions, and fish biomass productivity high too by Indian Ocean standards. The production of the once traditionally-managed small-scale fishery is severely declining and whether it is sustainable nowadays is extremely doubtful. At a time when Yemen is torn apart by a severe political and humanitarian crisis it is timely to review and update the current state of knowledge for scientists and managers, and thereby ease access to existing information, facilitating follow-on studies and evidence-based conservation and fisheries management.

  4. Tsunami generation in Stromboli island and impact on the south-east Tyrrhenian coasts

    Directory of Open Access Journals (Sweden)

    S. Tinti

    2003-01-01

    Full Text Available Stromboli is one of the most active volcanoes in the Aeolian island arc in south Tyrrhenian sea, Italy. In the last 100 years the most relevant volcanic eruptions have beenaccompanied by local tsunamis, that have caused damage and casualties. In some cases the direct mechanism of local tsunami generation is clear, i.e. pyroclastic flows entering the sea. In some others it is uncertain and some speculation concerning the collapse of the eruptive column on the sea surface or the failure of some underwater mass can be made. But the ordinary activity is unlikely to generate large regional tsunamis. These can be produced by the lateral collapse of the volcanic cone that geomorphological and volcanological  investigations have proven to have occurred repeatedly in the recent history of the volcano, with return period in the order of some thousands of years. The last episode is dated to less than 5 ka BP, and left the Sciara del Fuoco scar on the north-west flank of Stromboli. Based on previous studies, the possible collapse of the nortwestern sector of Stromboli and the consequent generation and propagation of a tsunami are explored. The impact on Stromboli and on the other islands of the Aeolian archipelago is estimated, as well as the impact on the coast of Sicily and the Tyrrhenian coasts of Calabria. The simulation is carried out by means of a double model: a Lagrangian block model to compute the motion of the collapsing mass, and a finite-element hydrodynamic model to compute the evolution of the tsunami. Two distinct tsunami simulations are carried out, one on a very fine grid around the source region to evaluate the tsunami near Stromboli, and one utilising a coarser grid covering the whole south-east Tyrrhenian sea to compute the tsunami propagation toward Sicily and Calabria. It is found that a huge-volume collapse of the north-western flank of the Stromboli cone is capable of producing a regional tsunami which is catastrophic at the source

  5. Acoustic habitat of an oceanic archipelago in the Southwestern Atlantic

    Science.gov (United States)

    Bittencourt, Lis; Barbosa, Mariana; Secchi, Eduardo; Lailson-Brito, José; Azevedo, Alexandre

    2016-09-01

    Underwater soundscapes can be highly variable, and in natural conditions are often dominated by biological signals and physical features of the environment. Few studies, however, focused on oceanic islands soundscapes. Islands in the middle of ocean basins can provide a good example of how untouched marine soundscapes are. Autonomous acoustic recordings were carried out in two different seasons in Trindade-Martin Vaz Archipelago, Southwestern Atlantic, providing nearly continuous data for both periods. Sound levels varied daily and between seasons. During summer, higher frequencies were noisier than lower frequencies, with snapping shrimp being the dominating sound source. During winter, lower frequencies were noisier than higher frequencies due to humpback whale constant singing. Biological signal detection had a marked temporal pattern, playing an important role in the soundscape. Over 1000 humpback whale sounds were detected hourly during winter. Fish vocalizations were detected mostly during night time during both summer and winter. The results show an acoustic habitat dominated by biological sound sources and highlight the importance of the island to humpback whales in winter.

  6. Emergence of rabbit haemorrhagic disease virus 2 in the archipelago of Madeira, Portugal (2016-2017).

    Science.gov (United States)

    Carvalho, Carina Luísa; Silva, Sara; Gouveia, Paz; Costa, Margarida; Duarte, Elsa Leclerc; Henriques, Ana Margarida; Barros, Sílvia Santos; Luís, Tiago; Ramos, Fernanda; Fagulha, Teresa; Fevereiro, Miguel; Duarte, Margarida Dias

    2017-06-21

    We report the detection of rabbit haemorrhagic disease virus 2 (RHDV2) in the Madeira archipelago, Portugal. Viral circulation was confirmed by RT-qPCR and vp60 sequencing. Epidemiological data revealed the outbreak initiated in October 2016 in Porto Santo affecting wild and domestic rabbits. It was then detected three months later on the island of Madeira. Five haplotypes were identified and a genetic overall similarity of 99.54 to 99.89% was observed between the two viral populations. Unique single nucleotide polymorphisms were recognised in the Madeira archipelago strains, two of which resulting in amino acid substitutions at positions 480 and 570 in the VP60 protein. Phylogenetic investigation by Maximum Likelihood showed all the vp60 sequences from the Madeira archipelago group together with high bootstraps. The analysis also showed that the Madeira archipelago strains are closely related to the strains detected in the south of mainland Portugal in 2016, suggesting a possible introduction from the mainland. The epidemiological data and high genetic similarity indicate a common source for the Porto Santo and Madeira RHDV2 outbreaks. Human activity related to hunting was most probably at the origin of the Madeira outbreak.

  7. The peopling of Madeira Archipelago (Portugal) according to HLA genes.

    Science.gov (United States)

    Arnaiz-Villena, A; Reguera, R; Ferri, A; Barbolla, L; Abd-El-Fatah-Khalil, S; Bakhtiyarova, N; Millan, P; Moscoso, J; Mafalda, A; Serrano-Vela, J I

    2009-02-01

    The Madeira-Porto Santo Archipelago was officially colonized in 1420 by Portuguese settlers. Its importance in Columbus' information for the American discovery and for slave traffic across the Atlantic is unquestionable. Thus, a complex peopling may have given rise to a present-day high admixture of ethnicities according to HLA genes. A sample of 173 healthy unrelated Madeirans was analysed and compared with 6986 HLA chromosomes from other worldwide populations. Genetic distances, neighbour-joining dendrograms and correspondence analyses were used for comparisons. Southern European, North African (including Canary Islands), Jewish and Mediterranean typical HLA alleles were found and genetic distances from Madeirans to these populations were the closest ones. In addition A*24-B*65-DRB1*0102-DQB1*0501 and A*68-B*08-DRB1*0301-DQB1*0201 haplotypes were newly found in Madeira and not found in any other population. Jewish-Armenian-Middle East haplotype (A*33-B*65-DRB1*0102-DQB1*0501) is one of the most common haplotypes; this haplotype is also present in Spaniards and North Africans. Quantitatively, Portuguese, North Africans (Algerians), Spaniards and Canary Islanders (in this order) are the most important parental populations to Madeirans. Results are discussed on the basis of the recorded historical peopling which does not show a noticeable African gene input in present-day Madeiran population according to our data; one of the closest related populations found is the Canary Islanders, suggesting that Guanche (Canary Islands first inhabitants) slaves gene flow is still noticed at present, both in Madeira and in Canary Islands populations.

  8. Persistent Aeolian Activity at Endeavour Crater, Mars

    Science.gov (United States)

    Chojnacki, M.; Michaels, T. I.; Fenton, L. K.

    2013-12-01

    Long-term monitoring of sites that are known to have active dunes and ripples is generally limited to 3 Mars-Years (MY). Here, we discuss new results of dune activity and albedo change in Endeavour crater (EC), Meridiani Planum (MP) that record eight MY of aeolian activity. MP dune fields often show large yearly variations in albedo; EC darkened by ~12% in TES albedo between MY 24 and 26 (from 0.14 to 0.12). THEMIS VIS albedo of dunes did not change significantly from MY 26 to 29, but did decrease notably (~15 %) in MY 30. These darkening events are most likely related to aeolian-driven dust cleaning (e.g., removal by saltating sand, dust devils). For example, the Opportunity rover (poised on the western rim of EC) observed evidence for a MY 31 dune field dust-clearing event. HiRISE monitoring of MP has shown it be one of the most active regions outside of north polar latitudes. Paired images of western EC taken 3 MY apart show clear evidence for dune modification that include: ripple migration, change in dune perimeters, exposure of previously buried light-toned rock, and/or burial of rock by sand (Fig. 1a-1b). Dune slip face movement is evident for most dunes, where crests and aprons advanced (2-7 m) in the downwind direction (to the SSE) at rates of 0.7-2.3 m per MY. Small dome dunes in the eastern EC were found to have a large degree of aeolian activity (e.g., deflation and/or translation) by an earlier study that used MGS-MRO images (MY 24-30). New MY 31 images validate earlier observations, showing clear evidence for bedform deflation where dunes often occupy less area (~50%) than in earlier MY 29 images (Fig. 1c-1d). Areal removal rates are on par with earlier estimates. Bedform modification and sand streamer orientation appear to be caused by a NNW wind regime, consistent with earlier observations, mesoscale modeling, and the transport direction of barchans to the west. Dunes in EC are now known to be periodically (consistently?) active from over a decade

  9. Momentum profile of aeolian saltation cloud

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The momentum profile of an aeolian saltation cloud is poorly understood. In this paper, height profiles for saltation momentum are reconstructed for three particle-size populations at four wind velocities based on profiles for mean particle velocity and relative particle concentration of saltation cloud obtained using particle image velocimetry in a wind tunnel. The results suggest that the saltation momentum profiles are characterized by peak curves with a maximum at some height above the surface. The height of this maximum increases with increasing wind velocity, but decreases with increasing particle size. It is linearly correlated with average saltation height and is comparable with the results of numerical simulations in a previous study. Our results confirm that Bagnold’s kink is an important feature of wind velocity profiles modified by the presence of saltating particles and that the height of the kink is closely related to the average trajectories of the saltating particles.

  10. Recent International and Domestic Migration in the Maltese Archipelago: An Economic Review

    Directory of Open Access Journals (Sweden)

    Rose Marie Azzopardi

    2012-05-01

    Full Text Available Migration strategies often permit densely populated island territories to alleviate unemployment, ease pressure on limited resources, and compensate for the absence of economic diversification. This paper evaluates two types of recent migratory flows affecting the Maltese archipelago: international migration to and from the islands triggered or intensified by European Union membership; and domestic, inter-island movements between the ‘mainland’ (Malta and the smaller island (Gozo.The descriptive statistics used are based on published data, whilst the qualitative evaluation is derived from focus groups and interviews with stakeholders. Conclusions suggest that emigration remains an overall positive experience at the individual level, with constructive spill-over effects, mingling of cultures and better use of resources at the national level. Such benefits can be expected to increase if authorities design policies which encourage rather than discourage migratory flows.

  11. Multi-Technique Study of a Martian Aeolian Sand Analog

    Science.gov (United States)

    Kuhlman, K.; Marshall, J.; Evans, N. D.; Luttge, A.

    2001-01-01

    Potential scientific returns from technological advances in various forms of microscopy and benchmarking of currently available in-situ measurements using an aeolian red dune sand from the central Australian desert. Additional information is contained in the original extended abstract.

  12. The rock magnetic characteristics of last glacial cycle loess from the island of Susak (Adriatic Sea, Croatia)

    Science.gov (United States)

    Hambach, Ulrich; Duchoslav, Maguerita; Rolf, Christian; Wacha, Lara; Frechen, Manfred; Galovic, Lidija

    2010-05-01

    Loess is by far the most important terrestrial archive that provides detailed palaeoclimatic information for the whole Quaternary. Loess covers wide areas in Asia and Southeast Europe where continental and sub-continental climates predominate. In Mediterranean climate settings, however, loess deposits are almost absent and the few existing sites provide invaluable palaeoclimatic information. Heller & Liu (1984) were the first who used magnetic susceptibility variations in Chinese loess to correlate the loess deposits to marine records. The susceptibility variations in the loess-palaeosol couplets resemble the pattern of the global ice volume record with higher values in palaeosols (interglacials) and lower values in loess (glacials). In most parts of the Eurasian loess belt, the intensity of pedogenesis leads to enhancement of magnetic minerals in soils. However, in other parts of the world under different climatic conditions, even depletion of the magnetic fraction could be observed. Furthermore, the wind strength during dust transport and loess deposition also seems to control the magnetic mineralogy. With stronger winds, minerals with higher density such as iron oxides are enriched during aeolian transport. Here we report on first results from a detailed rock magnetic investigation of a loess sequence from the Adriatic coast of Croatia. The Pjeskokop site is located on the island of Susak in the northern Dalmatian archipelago. On Susak, aeolian sands, sandy loess and loess have been deposited on Cretaceous marine limestones and form an up to 20 metres thick Pleistocene sediment blanket (Cremaschi 1990). At the Pjeskokop site, non-oriented samples were collected with narrow spacing (~2 cm) from a more than 11 metres high section. All samples were subjected to standard rock laboratory procedures. Detailed petrographical and grain size studies on parallel samples are in progress. A strongly rubified pedo-complex forms the base of the sequence. Weakly developed

  13. The Influence of Migration on Population Ageing in the Cres-Lošinj Archipelago

    Directory of Open Access Journals (Sweden)

    Sonja Podgorelec

    1999-12-01

    Full Text Available Demographic research in regard to the islands of Cres and Lošinj belongs in the domain of small population studies. Throughout history, and especially after World War II, the islands experienced very strong emigration and later immigration processes. After fifty or more years of continual emigration, immigration began on the island of Lošinj in the 1960s, and on Cres in the 1970s. This reversal from strong depopulation to a significant increase in the size of the population, if the islands are examined as a whole, reveals certain demographic particularities in comparison with other Croatian islands. The long-term reduction of the birth rate and prolonged emigration from settlements in the interior of Cres and from all the islands of the Lošinj archipelago has been the cause of many elderly, single-person and abandoned households. All the analytical indicators pertaining to the age structure are above the threshold which marks the beginning of population ageing. The average age on all the islands has for over thirty years been well above 30, whereas in the Lošinj archipelago it has been above the reproductive age – i.e. about 50. The age coefficient varies between 14.02 for Lošinj and 49.22 for Ilovik. The island of Lošinj itself has the youngest population, and hence the lowest indicators of ageing. The burden on the working-age contingent on each island has changed at a different rate and in a different direction during the last three inter-census periods. The co-efficient of dependency of the young is increasing on all the islands, while the co-efficient of dependency of the elderly age groups is falling on Lošinj, Ilovik, Unije and Cres. The reduction of the birth rate and the negative migration balance caused by high emigration of mainly young, unmarried males has caused a seks ratio imbalance in favour of females. The general co-efficient of females, according to the 1991 census was between 105.7 on Lošinj and 145.5 on Unije. The

  14. Phylogeographic analyses of submesophotic snappers Etelis coruscans and Etelis "marshi" (family Lutjanidae reveal concordant genetic structure across the Hawaiian Archipelago.

    Directory of Open Access Journals (Sweden)

    Kimberly R Andrews

    Full Text Available The Hawaiian Archipelago has become a natural laboratory for understanding genetic connectivity in marine organisms as a result of the large number of population genetics studies that have been conducted across this island chain for a wide taxonomic range of organisms. However, population genetic studies have been conducted for only two species occurring in the mesophotic or submesophotic zones (30+m in this archipelago. To gain a greater understanding of genetic connectivity in these deepwater habitats, we investigated the genetic structure of two submesophotic fish species (occurring ∼200-360 m in this archipelago. We surveyed 16 locations across the archipelago for submesophotic snappers Etelis coruscans (N = 787 and E. "marshi" (formerly E. carbunculus; N = 770 with 436-490 bp of mtDNA cytochrome b and 10-11 microsatellite loci. Phylogeographic analyses reveal no geographic structuring of mtDNA lineages and recent coalescence times that are typical of shallow reef fauna. Population genetic analyses reveal no overall structure across most of the archipelago, a pattern also typical of dispersive shallow fishes. However some sites in the mid-archipelago (Raita Bank to French Frigate Shoals had significant population differentiation. This pattern of no structure between ends of the Hawaiian range, and significant structure in the middle, was previously observed in a submesophotic snapper (Pristipomoides filamentosus and a submesophotic grouper (Hyporthodus quernus. Three of these four species also have elevated genetic diversity in the mid-archipelago. Biophysical larval dispersal models from previous studies indicate that this elevated diversity may result from larval supplement from Johnston Atoll, ∼800 km southwest of Hawaii. In this case the boundaries of stocks for fishery management cannot be defined simply in terms of geography, and fishery management in Hawaii may need to incorporate external larval supply into management

  15. Cossidae of the Socotra Archipelago (Yemen

    Directory of Open Access Journals (Sweden)

    Robert Borth

    2011-08-01

    Full Text Available The taxonomy of the family Cossidae (Lepidoptera of the Socotra Archipelago is revised. Five species are recognized, including two new species (Mormogystia brandstetteri and Meharia hackeri, and dubious identifications and records are discussed. Adults and genitalia are illustrated and bionomic details, molecular evidence and a synonymic checklist of Socotra Cossidae genera is provided. A review of their distribution reveals that at least 80 percent of Socotro`s Cossidae species are unique to the archipelago which is renowned for its endemism.

  16. Cossidae of the Socotra Archipelago (Yemen)

    Science.gov (United States)

    Borth, Robert; Ivinskis, Povilas; Saldaitis, Aidas; Yakovlev, Roman

    2011-01-01

    Abstract The faunistic composition of the family Cossidae (Lepidoptera) of the Socotra Archipelago is revised. Five species are recognized, including two new species (Mormogystia brandstetteri and Meharia hackeri), and dubious identifications and records are discussed. Adults and genitalia are illustrated and bionomic details, DNA barcodes and a synonymic checklist for Socotran cossids are provided. A review of their distribution reveals that at least 80 percent of Socotra’s cossids are unique to the archipelago, which is renowned for its endemism. A checklist listing all the species from generas Meharia, Mormogystia, Aethalopteryx, Azygophleps, as well as the synonymy and distribution is provided. PMID:21998527

  17. New littoral mite species (Acari, Oribatida, Fortuyniidae) from the Galápagos archipelago, with ecological and zoogeographical considerations.

    Science.gov (United States)

    Pfingstl, Tobias; Schatz, Heinrich

    2017-03-17

    Two species of Fortuyniidae, found on the Galápagos Islands (Ecuador) are described and illustrated based on the adult and juvenile instars. Alismobates galapagoensis sp. nov. was found on six islands of the archipelago, in littoral and supralittoral habitats. It is morphologically similar to A. inexpectatus Pfingstl & Schuster, 2012 from Bermuda, but differs from that species and all other known congeners by a prominent cuticular ridge on epimeron III among other unique character combinations. Litoribates caelestis gen. and sp. nov. was found on the islands Santa Cruz and Bartolomé in the littoral zone under Maytenus and mangroves. Notes on distribution and ecological preferences of both species are included.

  18. Plant species persistence and turnover on small Bahamian islands.

    Science.gov (United States)

    Morrison, Lloyd W

    2003-06-01

    I conducted surveys of the plant species occupying 136 small islands in the Exuma Cays and 58 small islands near Andros, Bahamas. Most species occurred on relatively few islands, and most islands contained relatively few species. Identities of the most common species differed between the two archipelagos. Comparisons with earlier surveys revealed species extinctions and immigrations. Turnover was relatively low on both a per island and a per species basis on both archipelagos, although significant spatial variation in turnover rates between archipelagos was found. Most islands experienced no turnover; islands on which turnover did occur were larger and had higher species richness. Likewise, most species did not turnover, although much variation existed in turnover rates among those that did. Experimental introductions of two species to very small islands naturally devoid of vegetation revealed that these islands could support plant life. One species survived on eight of ten islands for >9 years, including the effects of a moderate (class 2) hurricane. This hurricane caused substantial damage and loss of plant biomass, but resulted in no species extinctions on 30 small islands. Data for the small islands in this region, now spanning almost a decade, reveal that most populations are persistent over periods of years to decades, rarely going extinct or immigrating. Even moderate hurricanes seem to have little impact on species compositions.

  19. At the edge: Heritage and tourism development in Vietnam’s Con Dao archipelago

    Directory of Open Access Journals (Sweden)

    Philip Hayward

    2014-12-01

    Full Text Available This article outlines the development of Vietnam’s Con Dao archipelago (and Con Son island in particular as tourism destinations since the formal reunification of Vietnam in 1975. In particular it examines the nature of the area’s two main tourism attractions, Con Son’s prison sites and memorials and the archipelago’s natural environment, and how these have been marketed to and experienced by national and international tourists. This discussion also involves considerations of the concept of thanatourism and how the latter might be understood to operate in a Vietnamese context. The final sections of the article consider development plans and options for the archipelago; how these can be understood within national political contexts; and what problems there might be with their implementation.

  20. Multiple, independent colonizations of the Hawaiian Archipelago by the family Dolichopodidae (Diptera

    Directory of Open Access Journals (Sweden)

    Kari Roesch Goodman

    2016-11-01

    Full Text Available The family Dolichopodidae forms two of the four largest evolutionary radiations in the Hawaiian Islands across all flies: Campsicnemus (183 spp and the Eurynogaster complex (66 spp. They also include a small radiation of Conchopus (6 spp. A handful of other dolichopodid species are native to the islands in singleton lineages or small radiations. This study provides a phylogenetic perspective on the colonization history of the dolichopodid fauna in the islands. We generated a multi-gene data set including representatives from 11 of the 14 endemic Hawaiian dolichopodid genera to examine the history of colonization to the islands, and analyzed it using Bayesian and maximum likelihood phylogenetic methods. We used a subset of the data that included Conchopus and the eight genera comprising the Eurynogaster complex to estimate the first phylogenetic hypothesis for these endemic groups, then used Beast to estimate their age of arrival to the archipelago. The Eurynogaster complex, Campsicnemus and Conchopus are clearly the result of independent colonizations. The results strongly support the Eurynogaster complex as a monophyletic group, and also supports the monophyly of 4 of the 8 described genera within the complex (Adachia, Arciellia, Uropachys and Eurynogaster. Members of the family Dolichopodidae have been dispersing over vast distances to colonize the Hawaiian Archipelago for millions of years, leading to multiple independent evolutionary diversification events. The Eurynogaster complex arrived in the Hawaiian Archipelago 11.8 Ma, well before the arrival of Campsicnemus (4.5 Ma, and the even more recent Conchopus (1.8 Ma. Data presented here demonstrate that the Hawaiian Dolichopodidae both disperse and diversify easily, a rare combination that lays the groundwork for field studies on the reproductive isolating mechanisms and ecological partitioning of this group.

  1. High gene flow due to pelagic larval dispersal among South Pacific archipelagos in two amphidromous gastropods (Neritomorpha: Neritidae).

    Science.gov (United States)

    Crandall, E D; Taffel, J R; Barber, P H

    2010-06-01

    The freshwater stream fauna of tropical oceanic islands is dominated by amphidromous species, whose larvae are transported to the ocean and develop in the plankton before recruiting back to freshwater habitat as juveniles. Because stream habitat is relatively scarce and unstable on oceanic islands, this life history would seem to favor either the retention of larvae to their natal streams, or the ability to delay metamorphosis until new habitat is encountered. To distinguish between these hypotheses, we used population genetic methods to estimate larval dispersal among five South Pacific archipelagos in two amphidromous species of Neritid gastropod (Neritina canalis and Neripteron dilatatus). Sequence data from mitochondrial cytochrome oxidase I (COI) revealed that neither species is genetically structured throughout the Western Pacific, suggesting that their larvae have a pelagic larval duration (PLD) of at least 8 weeks, longer than many marine species. In addition, the two species have recently colonized isolated Central Pacific archipelagos in three independent events. Since colonization, there has been little or no gene flow between the Western and Central Pacific archipelagos in N. canalis, and high levels of gene flow across the same region in N. dilatatus. Both species show departures from neutrality and recent dates for colonization of the Central Pacific archipelagos, which is consistent with frequent extinction and recolonization of stream populations in this area. Similar results from other amphidromous species suggest that unstable freshwater habitats promote long-distance dispersal capabilities.

  2. The Alexander Archipelago wolf: a conservation assessment.

    Science.gov (United States)

    David K. Person; Matthew Kirchhoff; Victor van Ballenberghe; George C. Iverson; Edward. Grossman

    1996-01-01

    We summarized the scientific information available for the Alexander Archipelago wolf (Canis lupus ligoni) in the Tongass National Forest of southeast Alaska. Information concerning the morphology, distribution, taxonomy, genetics, and ecology of wolves are presented. Three issues for the conservation of wolves in southeast Alaska are discussed:...

  3. Magmatic activity at Islas Marias Archipelago, Gulf of California: Oceanic lithosphere with gabbroic sills versus Jurassic-Cretaceous arc components.

    Science.gov (United States)

    Schaaf, P. E. G.; Solis-Pichardo, G.; Hernandez-Trevino, T.; Villanueva, D.; Arrieta, G. F.; Rochin, H.; Rodriguez, L. F.; Bohnel, H.; Weber, B.

    2015-12-01

    Islas Marias Archipelago consists of four islands located in the mouth of the Gulf of California. Lithologically three of them (Maria Madre, San Juanito, and Maria Cleofas) are quite similar with a 165-170 Ma metamorphic basement, 75-85 Ma intrusive and extrusive rocks, and a sedimentary sandstone cover, which according to its foraminiferous content recorded multiple uplift and subsidence events related to the opening of the Gulf. However, these units are absent on Maria Magdalena island which is positioned between the other islands. Here, instead, oceanic lithosphere with pillow lavas and gabbroic sills, intercalated with sandstones form the dominant outcrops. Their geochemical and isotopic characteristics are similar to N-MORB with epsilon Nd values around +10 and 87Sr/86Sr of 0.70290. The gabbros are not older than 22 Ma. Magdalena island was obviously uplifted separately from the other islands of the archipelago, probably along a now hidden transform fault system along the East Pacific Rise. Metamorphic and igneous rocks of the other islands can be correlated to lithologically similar units in the Los Cabos Block, Baja California, or to the continental margin units in Sinaloa, Nayarit and Jalisco states when looking at their geochemical and geochronological signatures. Paleomagnetic studies on 35 sampling sites from all 4 islands give evidence for relatively small scale tectonic movements.

  4. Stepping-stones to the Edge: Artistic Expressions of Islandness in an Ocean of Islands

    Directory of Open Access Journals (Sweden)

    Laurie Brinklow

    2013-05-01

    Full Text Available Since the earliest of times, islands have captured the artistic imagination—and, often, for the artist who finds his or her muse in being ‘islanded’, the smaller the island the better. Archipelagos offer an ideal setting for artists who take their inspiration from place: on small islands off islands they can experience an intensity of island living they might not otherwise have on a main island: boundedness and connection, isolation and community. This paper examines expressions of islandness by artists who live on islands off islands that are poles apart—‘archipelagos’ of the Canadian North Atlantic and the Great Southern Ocean. It draws upon interviews with those artists and writers to consider the nature of humans’ attachment and attraction to islands, exploring through the lens of phenomenology what Stratford et al. call the “entanglement between and among islands”.

  5. Aeolian desertification and its control in Northern China

    Directory of Open Access Journals (Sweden)

    Wang Tao

    2014-12-01

    Full Text Available Aeolian desertification is a kind of land degradation through wind erosion resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in Northern China. To compare the results of remote sensing data in the late 1950s, 1975, 1987, 2000 and 2010, we can summarize that the expansion of aeolian desertified land in Northern China has been accelerated for 5 decades, as its annual expanded rate was 1,560 km2 during the late 1950s and 1975, 2,100 km2 between 1975 and 1988, 3,600 km2 from 1988 to 2000, and -1,375 km2 from 2000 to 2010. The desertified land kept expanding before 2000 and began to get rehabilitated since 2000. The impact of human activity on the aeolian desertification process is much more active than that from natural process which mainly incarnates on land use change (from rangeland to farmland and increased land use intensity (over-cultivation, over-grassing, and over-fuelwood collection. The natural vegetation cover destroyed by the human activities has accelerated the development of aeolian desertification. China has made great progresses in understanding and combating aeolian desertification through decades of effort and there were many projects carried out for the prevention and control purpose. The National Project of Grain for Green Program is the most important one with 1060 counties of 22 provinces involved. The objective is to withdraw 3.67 million ha of dry land farming and degraded steppe, and 5.13 million ha of aeolian desertified land suited to reforestation and re-vegetation will be rehabilitated. There are about 8 million ha of lands suffering from aeolian desertification will be brought under control in the next ten years and 26.67 million ha of windbreaks will be planted. The total investment from the central government is estimated to be 75 billion RMB (11 billion USD.

  6. Near-shore distribution of phyllosomas of the two only lobster species (Decapoda: Achelata present in Robinson Crusoe Island and endemic to the Juan Fernández archipelago Distribución costera de filosomas de las dos únicas especies de langostas (Decapoda: Achelata presentes en la Isla Robinson Crusoe y endémicas del archipiélago de Juan Fernández

    Directory of Open Access Journals (Sweden)

    ÁLVARO T PALMA

    2011-09-01

    Full Text Available Two lobster species coexist in the southeast Pacific Juan Fernández archipelago, Jasus frontalis (Milne-Edwards, 1837 and Acantharctus delfini (Bouvier, 1909. Like most lobster species they undergo a prolonged larval period, which is particularly long for J. frontalis (> 16 months. Though typical of Palinurids, this long larval duration is usually not thought to be conducive to local recruitment. While it is known that settlement is confined to the three islands of the archipelago (Robinson Crusoe, Alejandro Selkirk and Santa Clara and Desventuradas Islands (aprox. 800 km to the north, it remains poorly understood how local larval supply allows such distribution pattern. The goal of this study is twofold. Firstly, we aimed to characterize the distribution and abundance of the larvae of these two species around Robinson Crusoe Island using plankton tows and systematic hydrographic records between October 2008 to March of 2011, thus providing the first systematic and prolonged coupled biophysical observations in the nearshore of the archipelago. We hypothesize that spatial and temporal larval distribution patterns are associated to their retention around the archipelago, thus contributing to our knowledge of the physical and biological processes maintaining their extreme isolation. Secondly, using molecular genetics, we confirm a simple taxonomic criteria to distinguish the larvae of the two species, thus aiding future studies of larval dynamics. Throughout phyllosomas of A. delfini were more abundant than that of J. frontalis. Both species were more abundant on the northern shores of Robinson Crusoe Island and generally associated with warmer and saltier waters and mostly present in the samples collected during spring and summer months. Phyllosomas of both species were more abundant during nighttime tows in the upper layer of the water column surveyed suggesting a diurnal vertical migration behavior which, for coastal dwelling meroplanktonic

  7. Ticks on passerines from the Archipelago of the Azores as hosts of borreliae and rickettsiae.

    Science.gov (United States)

    Literak, Ivan; Norte, Ana Claudia; Núncio, Maria Sofia; de Carvalho, Isabel Lopes; Ogrzewalska, Maria; Nováková, Markéta; Martins, Thiago F; Sychra, Oldrich; Resendes, Roberto; Rodrígues, Pedro

    2015-07-01

    We examined the presence of borreliae and rickettsiae bacteria in ticks from wild passerine birds on three islands of the Archipelago of the Azores, the westernmost region of Palearctic. A total of 266 birds belonging to eight species from seven families were examined on São Miguel, Santa Maria and Graciosa islands in 2013. Ticks collected from these birds consisted of 55 Ixodes frontalis (22 larvae, 32 nymphs, 1 adult female) and 16 Haemaphysalis punctata nymphs. Turdus merula and Erithacus rubecula were the birds most infested with both tick species. Three T. merula in Santa Maria were infested with 4 I. frontalis infected with Borrelia turdi. No rickettsiae were found in the ticks. We report for the first time the presence of I. frontalis and B. turdi on the Azores islands and we showed that the spatial distribution reaches further west than previously thought.

  8. Magmatic control along a strike-slip volcanic arc: The central Aeolian arc (Italy)

    KAUST Repository

    Ruch, Joel

    2016-01-23

    The regional stress field in volcanic areas may be overprinted by that produced by magmatic activity, promoting volcanism and faulting. In particular, in strike-slip settings, the definition of the relationships between the regional stress field and magmatic activity remains elusive. To better understand these relationships, we collected stratigraphic, volcanic and structural field data along the strike-slip Central Aeolian arc (Italy): here the islands of Lipari and Vulcano separate the extensional portion of the arc (to the east) from the contractional one (to the west). We collected >500 measurements of faults, extension fractures and dikes at 40 sites. Most structures are NNE-SSW to NNW-SSE oriented, eastward dipping, and show almost pure dip-slip motion; consistent with an E-W extension direction, with minor dextral and sinistral shear. Our data highlight six eruptive periods during the last 55 ka, which allow considering both islands as a single magmatic system, in which tectonic and magmatic activity steadily migrated eastward and currently focus on a 10 km long x 2 km wide active segment. Faulting appears to mostly occur in temporal and spatial relation with magmatic events, supporting that most of the observable deformation derives from transient magmatic activity (shorter-term, days to months), rather than from steady longer-term regional tectonics (102-104 years). More in general, the Central Aeolian case shows how magmatic activity may affect the structure and evolution of volcanic arcs, overprinting any strike-slip motion with magma-induced extension at the surface.

  9. Magmatic control along a strike-slip volcanic arc: The central Aeolian arc (Italy)

    Science.gov (United States)

    Ruch, J.; Vezzoli, L.; De Rosa, R.; Di Lorenzo, R.; Acocella, V.

    2016-02-01

    The regional stress field in volcanic areas may be overprinted by that produced by magmatic activity, promoting volcanism and faulting. In particular, in strike-slip settings, the definition of the relationships between the regional stress field and magmatic activity remains elusive. To better understand these relationships, we collected stratigraphic, volcanic, and structural field data along the strike-slip central Aeolian arc (Italy): here the islands of Lipari and Vulcano separate the extensional portion of the arc (to the east) from the contractional one (to the west). We collected >500 measurements of faults, extension fractures, and dikes at 40 sites. Most structures are NNE-SSW to NNW-SSE oriented, eastward dipping, and show almost pure dip-slip motion, consistent with an E-W extension direction, with minor dextral and sinistral shear. Our data highlight six eruptive periods during the last 55 ka, which allow considering both islands as a single magmatic system, in which tectonic and magmatic activities steadily migrated eastward and currently focus on a 10 km long × 2 km wide active segment. Faulting appears to mostly occur in temporal and spatial relation with magmatic events, supporting that most of the observable deformation derives from transient magmatic activity (shorter term, days to months), rather than from steady longer-term regional tectonics (102-104 years). More in general, the central Aeolian case shows how magmatic activity may affect the structure and evolution of volcanic arcs, overprinting any strike-slip motion with magma-induced extension at the surface.

  10. Aeolian Slipface Processes on Earth and Mars

    Science.gov (United States)

    Cornwall, Carin; Jackson, Derek; Bourke, Mary; Cooper, Andrew

    2016-04-01

    The surface of Mars is dominated by aeolian features and many locations show ripple and dune migration over the past decade with some sediment fluxes comparable to terrestrial dunes. One of the leading goals in investigating aeolian processes on Mars is to explore the boundary conditions of sediment transport, accumulation, and dune mor-phology in relation to wind regime as well as to quantify migration rates and sediment flux. We combine terrestrial field observations, 3D computational fluid dynamics (CFD) modeling and remote sensing data to investigate com-plex, small scale wind patterns and grainflow processes on terrestrial and martian dunes. We aim to constrain grain flow magnitudes and frequencies that occur on slipface slopes of dunes in order to improve estimates of martian dune field migration and sediment flux related to wind velocity and flow patterns. A series of ground-based, high resolution laser scans have been collected in the Maspalomas dune field in Gran Canaria, Spain to investigate grainflow frequency, morphology and slipface advancement. Analysis of these laser scans and simultaneous video recordings have revealed a variety of slipface activity. We identify 6 different grain-flow morphologies including, hourglass shape (classic alcove formation with deposit fan below), superficial flow (thin lenses), narrow trough (vertical lines cm in width), sheet, column (vertical alcove walls), and complex (combi-nation of morphologies triggered simultaneously in the same location). Hourglass grainflow morphologies were the most common and occurred regularly. The superficial and narrow trough morphologies were the second most com-mon and frequently occurred in between large grain flows. Sheet grainflows were rare and unpredictable. These flows involved large portions of the slipface (metres across) and mobilized a substantial amount of sediment in one event. We have compared these grainflow morphologies from Maspalomas to those in martian dune fields and

  11. Paraliparis hawaiiensis, a new species of snailfish (Scorpaeniformes: Liparidae) and the first described from the Hawaiian Archipelago.

    Science.gov (United States)

    Stein, D L; Drazen, J C

    2014-05-01

    Paraliparis hawaiiensis n.sp. is described from the north-western Hawaiian Islands from two specimens collected at 2196 and 3055 m. It differs from other North Pacific Ocean species in its chin pore arrangement, tooth pattern and body proportions. Although liparid specimens have previously been collected from Hawaii, they were undescribed and are now lost. Therefore, this is the first liparid species described from the archipelago. In situ photographs of Hawaiian snailfishes are also shown and discussed here.

  12. Stromboli volcano (Aeolian Archipelago, Italy): An open window on the deep-feeding system of a steady state basaltic volcano

    Science.gov (United States)

    Bertagnini, A.; MéTrich, N.; Landi, P.; Rosi, M.

    2003-07-01

    Paroxysms at Stromboli are the most violent manifestations of the persistent activity and are related to the emission of small volumes (103-105 m3) of nearly aphyric HK-basaltic pumices. They offer the exceptional opportunity to detail the mixing-crystallization-degassing processes that occur in a steady state basaltic arc volcano. We present mineralogy, major, volatile, and trace element geochemistry of olivine-hosted melt inclusions of these pumices. In all the paroxysms, melt inclusions hosted in olivines Fo88-91 have recorded the parental melts rich in CaO (up to 14.5 wt %) but low in FeO (6-7 wt %). They demonstrate recurrent variations in the K2O content (1.6-1.3 wt %) and S/Cl ratios (1.2-0.8) of the melts that entered the deep system. Dynamic magma mixing between melts slightly distinct by their degree of evolution, rapid crystallization, and entrapment of gas-oversaturated melts during decompression are indicated by (1) the high density of irregular, clear melt inclusions, and embayments in homogeneous olivines (Fo87±0.5-Fo83±0.5), (2) the variable ratio between melt and gas bubble, and (3) the variability of melt inclusion compositions in both major (CaO/Al2O3 = 1-0.59) and volatile (3.4-1.8 wt % H2O, 1582-1017 ppm CO2) elements. FeO-rich melt inclusions in patchy, reversely zoned olivines also demonstrate interactions between ascending melt blobs and inherited olivine crystals. We propose a model involving a vertically extended dike-like system, where magmas progress and differentiate. On the basis of olivine growth rate calculations the volatile-rich magma blobs may ascend within few hours to few tenths of hours. Finally, we propose that sulfur degassing is possibly initiated during the early stage of magma differentiation.

  13. The lost Adventure Archipelago (Sicilian Channel, Mediterranean Sea): Morpho-bathymetry and Late Quaternary palaeogeographic evolution

    Science.gov (United States)

    Civile, Dario; Lodolo, Emanuele; Zecchin, Massimo; Ben-Avraham, Zvi; Baradello, Luca; Accettella, Daniela; Cova, Andrea; Caffau, Mauro

    2015-02-01

    The rise in sea level following the Last Glacial Maximum (LGM) radically altered pre-existing geography, pushing back the former shorelines. The effect of this eustatic change was particularly intense and dramatic in flat lands and shelves, such as the Sicilian Channel. High-resolution bathymetric maps and Chirp seismic profiles analyzed in this study show that the Sicilian Channel, now lying at depths rarely exceeding 150 m, has emerged several times during its geological history. The last emergence was during the Early Holocene, when kilometre-sized islands punctuated the north-western sector of the Sicilian Channel, the Adventure Plateau, forming a broad archipelago. Many of these islands, now located in water ranging in depth from - 10 to - 40 m, are composed of highly deformed Neogene sedimentary rocks (Talbot, Ante-Talbot, Nereo, and Pantelleria Vecchia banks), while others represent submarine Pleistocene volcanic edifices (Galatea, Anfitrite and Tetide banks). Sedimentary cover in all of these banks is virtually absent. High-resolution seismic profiles allowed the identification of post-LGM morphological markers associated with the marine transgression, some of which are characterized by melt water-pulses, as demonstrated by the presence of specific and distinct erosional features. Combining swath bathymetric data with the seismic profiles, we have generated two palaeogeographic maps of the former Adventure Archipelago at two specific time frames: (1) at the end of the Younger Dryas stadial (11,500 yr B.P., corresponding to a former sea level of - 60 m), and (2) at the end of the melt-water pulse 1B (11,200 yr B.P., corresponding to a former sea level of - 42 m). Maps clearly show that in just 300 years the geography of the archipelago has changed dramatically, so much so that some islands have disappeared and some have decreased by more than 80% of their pre-Younger Dryas size.

  14. The role of the Azores Archipelago in capturing and retaining incoming particles

    Science.gov (United States)

    Sala, Iria; Harrison, Cheryl S.; Caldeira, Rui M. A.

    2016-02-01

    The capacity of the Azores Archipelago to capture and retain incoming particles and organisms that are drifting with the oceanic currents was the main focus of this study. Using the Hybrid Coordinate Ocean Model coupled with the Connectivity Modeling System (an offline Lagrangian tool) a series of experiments were conducted to determine: i) the origin of the particles that reach the archipelago, ii) the capacity of each island sub-group to retain incoming particles and organisms, as well as the iii) oceanographic phenomena that lead to their transport and retention. The Gulf Stream (GS) and the westward propagating eddy corridors were identified as the main transport pathways affecting the Azores region. Eddy Kinetic Energy from altimetry data and Lyapunov exponent analysis suggest that eddies and filaments are the main delivery mechanisms. In the upper mixed layer, the GS and its associated eddies are a predominant regional oceanographic feature injecting particles from the north and west boundaries toward the Azores. The capacity to capture particles of each island sub-group was directly proportional to their size, while the retention time within the Azores region increased with depth, associated with the decrease in velocity of the intermediate water currents. This study opens new prospects to understand transport in the Mid-Atlantic (Azores) region and the islands' role in marine colonization, dispersal, fisheries recruitment and speciation.

  15. Joint analysis of electric and gravimetric data for volcano monitoring. Application to data acquired at Vulcano Island (southern Italy) from 1993 to 1996

    Science.gov (United States)

    Di Maio, Rosa; Berrino, Giovanna

    2016-11-01

    Understanding the dynamics of volcanic-hydrothermal systems is a key factor for discriminating between magmatic and hydrothermal nature of the sources responsible for the unrest phenomena observed in active volcanic areas. Numerous studies of geophysical data monitoring in volcano-geothermal districts has indeed proven that close relationships exist between the volcanic and hydrothermal fluid circulation and the anomalous geophysical signals observed at the ground surface. In this paper, a simultaneous analysis that integrates resistivity and gravity data is suggested as a useful tool to infer a consistent conceptual model of hydrothermal volcanic systems and their evolution. An application of the proposed analysis to repeated resistivity and gravity measurements performed on Vulcano Island (Aeolian Archipelago, Sicily, southern Italy) is presented with the aim of gaining information on the dynamics of the volcanic-hydrothermal system. The examined period ranges from December 1993 to September 1996, when significant changes in chemical properties, temperatures and emission rates of La Fossa crater fumaroles were observed, all indicating an increase in the flux of hot deep magmatic gases. The results of our analysis, which refers to a profile located at the foot of the northwest flank of La Fossa cone, suggest that underground cyclic water-to-vapour transformations govern the shallow hydrothermal system dynamics, generally described by a negative correlation between the monitored resistivity and gravity data. The occurrence of positive correlations between the two analysed parameters could be ascribed to volcanic dynamics, which would mask the normal hydrological and hydrothermal system behaviour.

  16. Chapter 2. The historical geography of an archipelago of polar explorers

    OpenAIRE

    Capelotti, P. J.

    2015-01-01

    An outline of the rationale for a workshop, held in Oslo, Norway, from 12-13 May 2015, to discuss the historic place names of the High Arctic archipelago of Franz Josef Land. The islands contain hundreds of place names that amount to a virtual catalog of polar exploration and explorers of the mid- to late-19th Century. As an example, three American expeditions spent seven years there between 1898-1905, in failed attempts to try to reach the geographic North Pole. However, in the process, they...

  17. Climate change influenced female population sizes through time across the Indonesian archipelago.

    Science.gov (United States)

    Guillot, Elsa G; Tumonggor, Meryanne K; Lansing, J Stephen; Sudoyo, Herawati; Cox, Murray P

    2013-01-01

    Lying at the crossroads of Asia and the Pacific world, the Indonesian archipelago hosts one of the world's richest accumulations of cultural, linguistic, and genetic variation. While the role of human migration into and around the archipelago is now known in some detail, other aspects of Indonesia's complex history are less understood. Here, we focus on population size changes from the first settlement of Indonesia nearly 50 kya up to the historic era. We reconstructed the past effective population sizes of Indonesian women using mitochondrial DNA sequences from 2,104 individuals in 55 village communities on four islands spanning the Indonesian archipelago (Bali, Flores, Sumba, and Timor). We found little evidence for large fluctuations in effective population size. Most communities grew slowly during the late Pleistocene, peaked 15-20 kya, and subsequently declined slowly into the Holocene. This unexpected pattern may reflect population declines caused by the flooding of lowland hunter/gatherer habitat during sea-level rises following the last glacial maximum.

  18. Mechanics of aeolian processes: Soil erosion and dust production

    Science.gov (United States)

    Mehrabadi, M. M.

    1989-01-01

    Aeolian (wind) processes occur as a result of atmosphere/land-surface system interactions. A thorough understanding of these processes and their physical/mechanical characterization on a global scale is essential to monitoring global change and, hence, is imperative to the fundamental goal of the Earth observing system (Eos) program. Soil erosion and dust production by wind are of consequence mainly in arid and semi arid regions which cover 36 percent of the Earth's land surface. Some recent models of dust production due to wind erosion of agricultural soils and the mechanics of wind erosion in deserts are reviewed and the difficulties of modeling the aeolian transport are discussed.

  19. A complex evolutionary history in a remote archipelago: phylogeography and morphometrics of the Hawaiian endemic Ligia isopods.

    Directory of Open Access Journals (Sweden)

    Carlos A Santamaria

    Full Text Available Compared to the striking diversification and levels of endemism observed in many terrestrial groups within the Hawaiian Archipelago, marine invertebrates exhibit remarkably lower rates of endemism and diversification. Supralittoral invertebrates restricted to specific coastal patchy habitats, however, have the potential for high levels of allopatric diversification. This is the case of Ligia isopods endemic to the Hawaiian Archipelago, which most likely arose from a rocky supralittoral ancestor that colonized the archipelago via rafting, and diversified into rocky supralittoral and inland lineages. A previous study on populations of this isopod from O'ahu and Kaua'i revealed high levels of allopatric differentiation, and suggested inter-island historical dispersal events have been rare. To gain a better understanding on the diversity and evolution of this group, we expanded prior phylogeographic work by incorporating populations from unsampled main Hawaiian Islands (Maui, Moloka'i, Lana'i, and Hawai'i, increasing the number of gene markers (four mitochondrial and two nuclear genes, and conducting Maximum likelihood and Bayesian phylogenetic analyses. Our study revealed new lineages and expanded the distribution range of several lineages. The phylogeographic patterns of Ligia in the study area are complex, with Hawai'i, O'ahu, and the Maui-Nui islands sharing major lineages, implying multiple inter-island historical dispersal events. In contrast, the oldest and most geographically distant of the major islands (Kaua'i shares no lineages with the other islands. Our results did not support the monophyly of all the supralittoral lineages (currently grouped into L. hawaiensis, or the monophyly of the terrestrial lineages (currently grouped into L. perkinsi, implying more than one evolutionary transition between coastal and inland forms. Geometric-morphometric analyses of three supralittoral clades revealed significant body shape differences among them

  20. Shallow hydrothermal alteration and permeability changes in pyroclastic deposits: a case study at La Fossa cone (Vulcano island, Italy):

    Science.gov (United States)

    Cangemi, Marianna; Madonia, Paolo; Speziale, Sergio; Oliveri, Ygor

    2016-04-01

    La Fossa cone at Vulcano, the southernmost island of the Aeolian volcanic archipelago (Italy), has been characterized by an intense fumarolic activity since its last eruption dated 1888-90. Mineralogical alteration induced by shallow hydrothermal circulation has significantly reduced the permeability of the volcanic products, causing important feedbacks on the circulation of fluids in the shallowest portion of the volcanic edifice. The summit area of the cone is sealed by a quite continuous coating surface, fostering the condensation of hydrothermal fluids inside the volcanic edifice. The combination of fractures and volcano-stratigraphic discontinuities, conveying hydrothermal fluids, makes significant rock volumes prone to slide seaward, as occurred in 1988 during the main unrest experienced by Vulcano island since its last eruption. Similar instability conditions are found over the Forgia Vecchia crater rim area, formed by phreatic activity on the NE flank of the cone, where tensile fracturing and hydrothermal circulation interacts with mutual negative feedbacks. In the behalf of the DPC-INGV V3 Project 2012-15 we investigated the mineralogical composition and the hydraulic conductivity (under saturated conditions) of volcanic deposits potentially prone to hydrothermal fluid circulation, for evaluating their ability in retaining water, creating favourable conditions for gravitational instability. We also measured rainfall rate and volumetric soil moisture content in two automated stations located in different areas, with and without active hydrothermal circulation. We found that hydrothermal alteration transforms volcanic products into clay minerals, significantly reducing permeability of volcanic deposits. Argillified volcanic materials show background water contents, modulated by impulsive increments following rainfalls, higher than unaltered pyroclastic deposits, due to the combination of lower permeability and direct condensation of hydrothermal vapour. The

  1. Aeolian sediment flux derived from a natural sand trap

    NARCIS (Netherlands)

    Weerd, van der A.J.; Wijnberg, K.M.

    2016-01-01

    In 2011, a mega-nourishment (the ‘Sand Motor’) was constructed along the Dutch Coast. Since it is a pilot project, its evolution is closely monitored. This paper presents first results on the temporal variation in aeolian sediment transport across the nourishment, based on (a) the rate of infill ove

  2. A new conceptual model for aeolian transport rates on beaches

    NARCIS (Netherlands)

    De Vries, S.; Stive, M.J.F.; Van Rijn, L.; Ranasinghe, R.

    2012-01-01

    In this paper a new conceptual model for aeolian sediment transport rates is presented. Traditional sediment transport formulations have known limitations when applied to coastal beach situations. A linear model for sediment transport rates with respect to wind speed is proposed and supported by

  3. Aeolian Sediment Transport Pathways and Aerodynamics at Troughs on Mars

    Science.gov (United States)

    Bourke, Mary C.; Bullard, Joanna E.; Barnouin-Jha, Olivier S.

    2004-01-01

    Interaction between wind regimes and topography can give rise to complex suites of aeolian landforms. This paper considers aeolian sediment associated wit11 troughs on Mars and identifies a wider range of deposit types than has previously been documented. These include wind streaks, falling dunes, "lateral" dunes, barchan dunes, linear dunes, transverse ridges, sand ramps, climbing dunes, sand streamers, and sand patches. The sediment incorporated into these deposits is supplied by wind streaks and ambient Planitia sources as well as originating within the trough itself, notably from the trough walls and floor. There is also transmission of sediment between dneTsh. e flow dynamics which account for the distribution of aeolian sediment have been modeled using two-dimensional computational fluid dynamics. The model predicts flow separation on the upwind side of the trough followed by reattachment and acceleration at the downwind margin. The inferred patterns of sediment transport compare well with the distribution of aeolian forms. Model data indicate an increase of wind velocity by approx. 30 % at the downwind trough margin. This suggests that the threshold wind speed necessary for sand mobilization on Mars will be more freqentmlye t in these inclined locations.

  4. Aeolian sands as material to construct low-volume roads

    CSIR Research Space (South Africa)

    Paige-Green, P

    2011-07-01

    Full Text Available Aeolian sands are widespread in many semi-arid to arid areas of the world and often provide the only economic source of construction materials for low volume roads. Experience in southern Africa over a number of decades has shown that provided...

  5. Aeolian Desertification and its Control in Northern of China

    Science.gov (United States)

    Wang, Tao

    2017-04-01

    Aeolian desertification is land degradation through wind erosion mainly resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in Northern China. To compare the analyses results of remote sensing data in late of 1950, 1975, 1987, 2000 and 2010, we can summarize that the development of aeolian desertified land in Northern China had being accelerated for 5 decades, as its annual expanded rate was 1,560 km2 during late of 1950 and 1975, 2,100 km2 between 1975 and 1988, 3,600 km2 from 1988 to 2000 and -1375 km2 from 2000 to 2010. The whole situation of desertification comes to be depraved before 2000 and to be improve after 2000. The human impact is much more active than natural one on the process of aeolian desertification which mainly incarnates on the changes of the landuse fashion (from rangeland to farmland) and enhance of landuse intensity (over-cultivation, over-grassing and over-fuelwood collection). The natural vegetation had been destroyed by the human activities that had accelerated to the development or/and control of aeolian desertification. China has made much progresses in understanding and combating aeolian desertification through many efforts for decades and there were many projects have been carried out. One of among them is the National Project of Grain for Green Program and more than 1000 counties in 22 provinces have been included into this project. The objective is to withdraw 3.67 million ha of dry land farming and degraded steppe, and 5.13 million ha of aeolian desertified land suited to reforestation and revegetation will be rehabilitated. There are about 8 million ha of lands under the threats of aeolian desertified land will be brought under control in the next ten years and 26.67 million ha of windbreaks will be planted. The total financial input is estimated to 75 billion Yuan (11 billion US) what is entirely from the central government.

  6. Spatial differences of aeolian desertification responses to climate in arid Asia

    Science.gov (United States)

    Wang, Xunming; Hua, Ting; Lang, Lili; Ma, Wenyong

    2017-01-01

    Most areas of arid Asia are covered by aeolian dunes, sand sheets, gravels, and desert steppes, and may jeopardize nearly 350 million people if climate change increases aeolian desertification. Although the aeolian desertification is mainly triggered by climate changes are extensively acknowledged, the responses of aeolian desertification to various climate scenarios are poorly understood. Based on the tight combinations of dune activity index (DAI) trends and of aeolian desertification, here the spatial differences of aeolian desertification responses on various climate scenarios were reported. The analyzed results show that the variations in temperature, precipitation and wind regime have no significant contributions on aeolian desertification in the extremely arid Asia. From the early to blooming periods of vegetation growth, although temperature rise may benefit vegetation growths in some high latitudes and altitudes, the temperature rise may increase aeolian desertification in most arid Asia regions such as Mongolia, West and Central Asia. In arid Asia, although precipitation increases may benefit the rehabilitation, decreases in precipitation is not the key role on aeolian desertification occurrences in extremely arid regions. From the early to blooming periods of vegetation growths, spatial trends of the sensitivity of aeolian desertification to wind regime varied. Generally, at the regional scales there are relative high sensitivities for aeolian desertification to climate changes in the eastern and western regions of arid Asia, and the climate changes may not play important roles on aeolian desertification occurrence in the central regions. The spatial differences of aeolian desertification responses to climate changes indicate various strategies for aeolian desertification combating are needed in different regions of arid Asia.

  7. New Paleomagnetic Data for the Franz Josef Land Archipelago and their Tectonic Consequences

    Science.gov (United States)

    Abashev, V.; Mikhaltsov, N.

    2014-12-01

    On the base of field work on the Franz Josef Land archipelago (FJL) in 2010 and 2011 the new paleomagnetic data are obtained from the Jurassic-Early Cretaceous magmatic complexes. Main focus of this work was concentrated on the Early-Jurassic basalts widely represented on the Hooker island [1]. Together with the previous data [2] statistically reasonable paleomagnetic pole for the age boundary of 190 million years for the FJL is received (PLat.=62.4; PLon.=140.2; dp/dm=5.5/5.0; N=13). Paleomagnetic data allow to assume that the position of the FJL relative to the Europe in the Early Jurassic significantly differs from the present one. But to the Early Cretaceous it reached relative position very close to the presently observed [2]. We suggest that at least during Early-Middle Jurassic there was rifting processes between the North Barentz terrane (FJL and (may be) Svalbard) and the other part of the European tectonic domain. This rift was accompanied by shifting of the FLJ to the north-eastward on about 500 km. Also obtained paleomagnetic data agree with a hypothesis assuming that the FJL was passing over the Icelandic-Siberian hot spot during Jurassic-Cretaceous time: main paleolatitudes correspond to the Island's present latitude and the paleolatitude of the Siberian trapps. Paleomagnetic study of FJL has a reconnaissance character and cannot lead to any ultimate deductions as the data is obviously not enough. And further work on the basaltic covers of the archipelago seems to be very promising. Research was supported by grant RFBR 13-05-00177. 1. Karyakin Yu.V., Shipilov E.V. Geochemical Specialization and the 40Ar/39Ar Age of Basaltoid Magmatism in the Aleksandra Land, Northbrook, Hooker, and Hayes Island (Franz Josef Land Archipelago) // Doklady Akademii Nauk, 2009, Vol.425, No.2, P. 213-217 (in Russian). 2. Bragin V.Yu., Karyakin Yu.V., Mikhaltsov N.E. The Franz Josef Land archipelago: reconnaissance paleomagnetic data // Large igneous provinces of Asia

  8. Character and provenance of aeolian sediments in northeast Thailand

    Science.gov (United States)

    Nichol, Janet E.; Nichol, Douglas W.

    2015-12-01

    Aeolian activity is not generally associated with the humid tropics, and although reports of loess-like soils in various locations in southeast Asia exist, these mainly lack the detailed analysis to set them in meaningful spatial or historical context. This paper examines the red and yellow sandy sediments of the Khorat Plateau in northeast Thailand which have been variously referred to as 'cover sands', 'loessial soils' or 'loess'. The sediments are referred to as having alluvial, biological as well as aeolian origin, and a date of 9-35 ka is reported. The study compares the Khorat sediments physically and geochemically with loess and aeolian sediments from other regions, as well as with other sites in southeast Asia which are reported here. The moderate degree of particle sorting and unimodal sizes of the sediments along with a sub-spherical sub-rounded form, supports previous diagnoses of an aeolian origin. Geochemical analysis of the Khorat sediments indicates severe depletion in both mobile and immobile elements, which are even more depleted than other southeast Asian loessic soils examined. This depletion, along with the only moderate particle sorting, suggests the source of the sediments to be the local weathered sandstones outcropping around the edge of the Khorat Plateau. The dissimilarity of the Khorat sediments from Upper Continental Crust (UCC) elemental values supports this, as homogenisation would occur if diverse source areas were involved. The study suggests that aeolian sediments of humid tropical regions warrant more attention as climate proxy markers, due to the dissimilarity between the present climate and conditions required for their formation.

  9. Submarine Hydrothermal Activity on the Aeolian Arc: New Evidence from Helium Isotopes

    Science.gov (United States)

    Lupton, J.; de Ronde, C.; Baker, E.; Sprovieri, M.; Bruno, P.; Italiano, F.; Walker, S.; Faure, K.; Leybourne, M.; Britten, K.; Greene, R.

    2008-12-01

    In November 2007 we conducted a water-column and seafloor mapping study of the submarine volcanoes of the Aeolian Arc in the southern Tyrrhenian Sea aboard the R/V Urania. A total of 26 CTD casts were completed, 13 vertical casts and 13 tows. In addition to in situ measurements of temperature, conductivity, pressure and suspended particles, we also collected discrete samples for helium isotopes, methane, and trace metals. The helium isotope ratio, which is known to be an unambiguous indicator of hydrothermal input, showed a clear excess above background at 5 out of the 10 submarine volcanoes surveyed. We found the strongest helium anomaly over Marsili seamount, where the 3He/4He ratio reached maximum values of δ3He = 23% at 610 m depth compared with background values of ~7%. We also found smaller but distinct δ3He anomalies over Enerato, Eolo, Palinuro, and Secca del Capo. We interpret these results as indicating the presence of hydrothermal activity on these 5 seamounts. Hydrothermal venting has been documented at subsea vents offshore of the islands of Panarea, Stromboli, and Vulcano (Dando et al., 1999; Di Roberto et al., 2008), and hydrothermal deposits have been sampled on many of the submarine volcanoes of the Aeolian Arc (Dekov and Savelli, 2004). However, as far as we know this is the first evidence of present day hydrothermal activity on Marsili, Enerato, and Eolo. Samples collected over Filicudi, Glabro, Lamentini, Sisifo, and Alcioni had δ3He very close to the regional background values, suggesting either absence of or very weak hydrothermal activity on these seamounts. Helium isotope measurements from the background hydrocasts positioned between the volcanoes revealed the presence of an excess in 3He throughout the SE Tyrrhenian Sea. These background profiles reach a consistent maximum of about δ3He = 11% at 2300 m depth. Historical helium profiles collected in the central and northern Tyrrhenian Sea in 1987 and 1997 do not show this deep 3He

  10. Liberalism in the Islamic World and its influence in the Malay Archipelago: Model in Indonesia

    Directory of Open Access Journals (Sweden)

    Abbas Mansur Tamam

    2014-06-01

    Full Text Available Liberalism means here Orientalist attempt to attract even Islam conformity with the principles of Western liberalism in form and substance. Hence Zhardha in the Islamic world have to do Orientalism, which under his leadership became the U.S. currently wants Islam that corresponds to the values of modernity and secularism and Western liberalism. And this phenomenon coincides appearance in the Islamic world with its appearance Malay archipelago and Indonesia to face particular Alholanda since colonial days, and then taking this trend develops even have an influence on contemporary history in these islands. So this includes talking on two things: Orientalist role for the emergence of liberalism in the Islamic world, and its influence in the Malay islands.

  11. [Helminth fauna of the bank vole myodes glareolus (Schreber, 1780) in the Kizhi Archipelago].

    Science.gov (United States)

    Bugmyrin, S V; Korosov, A V; Bespyatova, L A; Ieshko, E P

    2015-01-01

    The present study was aimed to examine the specific features of the helminth fauna in insular populations of the bank vole (Myodes glareolus) in the north of the species range. The material was collected in and nearby the Kizhi Archipelago (Lake Onega, 62°1' N 35°12' E) during August 1997, 2005-2007, 2012 and 2013. Small mammals were trapped on 23 islands (varying from 2 to 15,000 ha) and on the mainland. Helminthological met- hods were applied to examine 301 specimens of M glareolus. Fourteen helminth species were found: trematodes--Skrjabinoplagiorchis vigisi; cestodes--Paranoplocephala omphalodes, P. gracilis, Catenotaenia henttoneni, Taenia mustelae, Cladotaenia globife- ra, Spirometra erinacei; nematodes--Trichocephalus muris, Aonchotheca murissylvatici, Hepaticola hepatica, Heligmosomum mixtum, Heligmosomoides glareoli, Longistriata minuta, Syphacia petrusewiczi. The parasites S. vigisi, S. erinaci, H. hepatica and T. muris were identified in the bank vole in Karelia for the first time. Significant differences were detected between the helminth faunas of local insular populations of the bank vole. A distinctive feature of all small islands was that samples from them lacked the widespread pa- rasitic nematode Heligmosomum mixtum. The studies have confirmed the general trends observed in the parasite fauna of most isolated populations of small mammals: a poorer species diversity and high infestation rates with certain species of parasites. The Kizhi Archipelago is characterized by the specific high abundance of regionally rare parasite species (H hepatica, A. murissylvatici), and by the absence of common parasites (H. mixtum, H. glareoli).

  12. Aeolian Sediment Trapping Efficiencies of Sparse Vegetation and its Ecohydrological Consequences in Drylands

    Science.gov (United States)

    Gonzales, H. B.; Ravi, S.; Li, J. J.; Sankey, J. B.

    2016-12-01

    Hydrological and aeolian processes control the redistribution of soil and nutrients in arid and semi arid environments thereby contributing to the formation of heterogeneous patchy landscapes with nutrient-rich resource islands surrounded by nutrient depleted bare soil patches. The differential trapping of soil particles by vegetation canopies may result in textural changes beneath the vegetation, which, in turn, can alter the hydrological processes such as infiltration and runoff. We conducted infiltration experiments and soil grain size analysis of several shrub (Larrea tridentate) and grass (Bouteloua eriopoda) microsites and in a heterogeneous landscape in the Chihuahuan desert (New Mexico, USA). Our results indicate heterogeneity in soil texture and infiltration patterns under grass and shrub microsites. We assessed the trapping effectiveness of vegetation canopies using a novel computational fluid dynamics (CFD) approach. An open-source software (OpenFOAM) was used to validate the data gathered from particle size distribution (PSD) analysis of soil within the shrub and grass microsites and their porosities (91% for shrub and 68% for grass) determined using terrestrial LiDAR surveys. Three-dimensional architectures of the shrub and grass were created using an open-source computer-aided design (CAD) software (Blender). The readily available solvers within the OpenFOAM architecture were modified to test the validity and optimize input parameters in assessing trapping efficiencies of sparse vegetation against aeolian sediment flux. The results from the numerical simulations explained the observed textual changes under grass and shrub canopies and highlighted the role of sediment trapping by canopies in structuring patch-scale hydrological processes.

  13. Phylogeographic Analyses of Submesophotic Snappers Etelis coruscans and Etelis “marshi” (Family Lutjanidae) Reveal Concordant Genetic Structure across the Hawaiian Archipelago

    Science.gov (United States)

    Andrews, Kimberly R.; Moriwake, Virginia N.; Wilcox, Christie; Grau, E. Gordon; Kelley, Christopher; Pyle, Richard L.; Bowen, Brian W.

    2014-01-01

    The Hawaiian Archipelago has become a natural laboratory for understanding genetic connectivity in marine organisms as a result of the large number of population genetics studies that have been conducted across this island chain for a wide taxonomic range of organisms. However, population genetic studies have been conducted for only two species occurring in the mesophotic or submesophotic zones (30+m) in this archipelago. To gain a greater understanding of genetic connectivity in these deepwater habitats, we investigated the genetic structure of two submesophotic fish species (occurring ∼200–360 m) in this archipelago. We surveyed 16 locations across the archipelago for submesophotic snappers Etelis coruscans (N = 787) and E. “marshi” (formerly E. carbunculus; N = 770) with 436–490 bp of mtDNA cytochrome b and 10–11 microsatellite loci. Phylogeographic analyses reveal no geographic structuring of mtDNA lineages and recent coalescence times that are typical of shallow reef fauna. Population genetic analyses reveal no overall structure across most of the archipelago, a pattern also typical of dispersive shallow fishes. However some sites in the mid-archipelago (Raita Bank to French Frigate Shoals) had significant population differentiation. This pattern of no structure between ends of the Hawaiian range, and significant structure in the middle, was previously observed in a submesophotic snapper (Pristipomoides filamentosus) and a submesophotic grouper (Hyporthodus quernus). Three of these four species also have elevated genetic diversity in the mid-archipelago. Biophysical larval dispersal models from previous studies indicate that this elevated diversity may result from larval supplement from Johnston Atoll, ∼800 km southwest of Hawaii. In this case the boundaries of stocks for fishery management cannot be defined simply in terms of geography, and fishery management in Hawaii may need to incorporate external larval supply into management plans

  14. Towards a phoenix phase in aeolian research: shifting geophysical perspectives from fluvial dominance

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, Jeffrey J [Los Alamos National Laboratory; Field, Jason P [UNIV OF ARIZONA; Breshears, David D [UNIV OF ARIZONA

    2008-01-01

    Aeolian processes are a fundamental driver of earth surface dynamics, yet the importance of aeolian processes in a broader geosciences context may be overshadowed by an unbalanced emphasis on fluvial processes. Here we wish to highlight that aeolian and fluvial processes need to be considered in concert relative to total erosion and to potential interactions, that relative dominance and sensitivity to disturbance vary with mean annual precipitation, and that there are important scale-dependencies associated with aeolian-fluvial interactions. We build on previous literature to present relevant conceptual syntheses highlighting these issues. We then highlight the relative investments that have been made in aeolian research on dust emission and management relative to that in fluvial research on sediment production. Literature searches highlight that aeolian processes are greatly understudied relative to fluvial processes when considering total erosion in different environmental settings. Notably, within the USA, aeolian research was triggered by the Dust Bowl catastrophe of the 1930s, but the resultant research agencies have shifted to almost completely focusing on fluvial processes, based on number of remaining research stations and on monetary investments in control measures. However, numerous research issues associated with intensification of land use and climate change impacts require a rapid ramping up in aeolian research that improves information about aeolian processes relative to fluvial processes, which could herald a post-Dust Bowl Phoenix phase in which aeolian processes are recognized as broadly critical to geo- and environmental sciences.

  15. Contemporary proglacial aeolian sediment transport in West Greenland

    Science.gov (United States)

    Bullard, J. E.; Austin, M. J.

    2007-12-01

    Glacial erosion processes produce significance quantities of fine sediments that are washed out from beneath glaciers by meltwater. When deposited on the glacier floodplain they dessicate and strong ice-driven winds can entrain and transport them across the landscape resulting in the formation of sand dunes and loess, and adding very fine particles (dust) to the atmosphere. Recent studies suggest that locally-generated dust can play an important role in regulating albedo and the melting rate of glaciers. Very few field process studies have examined the relationship between sediment-delivery to the proglacial floodplain by meltwater and the subsequent aeolian erosion and deposition of these fine sediments. This research reports the use of semi-isokinetic directional sediment samplers to make an initial assessment of the rates of transport of dust and sand in Sandflugtdalen, a valley adjacent to the West Greenland ice sheet. Vertical arrays (z(m) = 0.18, 0.43, 0.85, 1.4) of samplers were deployed in a down valley transect over a distance of 4 km. Trapped sediments were retrieved after intervals of 1 week and 9 weeks. The mass of sediment collected in the traps varied from 0.002-3.62 g cm2 wk-1. As expected, near surface traps collected more, and coarser, sediment than those deployed at 1.4 m height but the decrease in mass of sediment with height was highly variable. The array closest to the glacier trapped the greatest quantity of suspended sediment and the density of suspended sediment decreased with distance down valley. The flux of aeolian sediment comprises clays, silts and sand-sized particles. Areas of aeolian entrainment, transport and deposition are closely linked to the development and distribution of sediments on the proglacial floodplain which varies considerably in terms of surface roughness. At the east end of the valley, close to the ice sheet, aeolian sediment flux is controlled by sediment supply and topography rather than wind speed. Further down

  16. Aeolian Coastal Landscapes in changes (a study from Tahkuna, Estonia)

    Science.gov (United States)

    Anderson, A.

    2012-04-01

    The openness of the coast to the winds and storm waves has an important part in changing aeolian coastal landscapes as well as anthropogenic factor. The aeolian coastal landscapes are probably the most dynamic areas. Occurrence of aeolian coastal landscapes in Estonia is limited. They consist of sandy beaches, sandy beach ridges and dunes. The coastal ecosystems are strongly affected by their topography, based on the character of deposits and moisture conditions. The majority of their ecosystems are quite close to the specific natural habitat. These ecosystems are represented in the list of the European Union Habitats (Natura 2000). In recent decades human influence has changed the landscape over time in different activities (recreation, trampling, off-road driving) and their intensities, which has led to destruction or degradation of various habitats. Previously coastal landscapes were used for forestry and pasture. Nowadays one of the most serious threats to open landscape is afforestation. This study examines the relationships between landscape components during last decades. Trying to find out how much aeolian coastal landscapes are influenced by natural processes or human activities. The results are based on cartographic analysis, fieldwork data. The method of landscape complex profile was used. The profiles show a cross-sections of landforms and interrelationships between landscape components, most frequently describing the relations between soils and vegetation. In each sample point the mechanical composition of sediments, vegetation cover and soil is determined. Results show that changes in landscapes are induced by their own development as well as changes in environmental factors and human activities. Larger changes are due to increase of coastal processes activity. These processes can be observed in sandy beaches, which are easily transformed by waves. Higher sea levels during storm surges are reaching older beach formation, causing erosion and creating

  17. Holocene aeolian sediments on the NE Tibetan Plateau

    Science.gov (United States)

    Stauch, G.; Lehmkuhl, F.; Hilgers, A.; Zhao, H.

    2012-04-01

    The semiarid climate of the northeastern Tibetan Plateau supports the formation of different types of aeolian sediments and landforms during the Holocene. Aeolians silts and sands in the catchment of the Donggi Cona in an elevation above 4000m to 4800 m asl reflect variable climate conditions during that time as well as different sediment sources. Based on 51 OSL datings and catchment wide geomorphological mapping a complex pattern of long and short distance sediment transport has been reconstructed. Only few aeolian archives are preserved from the late Pleistocene in this mountain environment indicating cold and dry climate conditions which prevented a continuous accumulation. During the early Holocene a phase of increased aeolian sedimentation of sand at the slopes of the mountains has been reconstructed. The sand originated from a large alluvial fan which was highly active during the Pleistocene. In addition, a thin loess cover is preserved at a few sites in the neighboring mountains ranges. The sedimentation of the loess started around 2000 years later than the sedimentation of the sand at the foot slope. Both archives are related to an increase in precipitation at the northern margin of the Tibetan Plateau which was related to a strengthening of the Asian Monsoon during that time. The wetter climate conditions favored the development of a vegetation cover which leads to the trapping and fixation of the aeolian sediments. However, with a further strengthening of the Monsoon systems these archives subsequently eroded due to higher run off and accumulated as colluvial and fluvial deposits in the basins. These phase lasted until 6 ka. A second aeolian period started at around 3 ka with the formation new dunes in the basins. This period can be associated with dry and cold climate of the late Holocene supporting the reactivation of the sand in the area. This might be further enhanced by an increased human impact by grazing during the late Holocene and resulting

  18. Occurrences of whale shark (Rhincodon typus Smith, 1828 in the Saint Peter and Saint Paul archipelago, Brazil

    Directory of Open Access Journals (Sweden)

    FHV. Hazin

    Full Text Available The Saint Peter and Saint Paul Archipelago in the central tropical Atlantic, is an important ground of whale sharks that are commonly sighted throughout the year close to the fishing boats in the adjacencies of the islands. In sightings reported between February 2000 and November 2005, the lengths of the individuals ranged between 1.8 to 14.0 m. The causes of these concentrations in the archipelago are still unclear, once there are no upwellings and plankton concentrations for feeding, and no reproductive activities were reported. Nevertheless, they could be associated to the spawning period of the abundant flying fishes, mainly in the first semester, when sightings were more frequent.

  19. Human Causes of Aeolian Desertification in Northern China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China.

  20. Spatiotemporal heterogeneity of phytoplankton diversity and its relation to water environmental factors in the southern waters of Miaodao Archipelago, China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Wei; LI Fen; SHI Honghua; HUO Yuanzi; LI Yan; CHI Yuan; GUO Zhen

    2016-01-01

    To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter (73), moderate in autumn (70), but lower in summer (31) and spring (27). The species richness index in autumn (5.92) and winter (4.28) was higher than that in summer (2.83) and spring (1.41). The Shannon-Wiener diversity index was high in autumn (2.82), followed by winter (1.99) and summer (1.92), and low in spring (0.07). The species evenness index in autumn (0.46) and summer (0.39) was higher than that in winter (0.32) and spring (0.02). On the basis of principal component analysis (PCA) and redundancy analysis (RDA), we found that dissolved inorganic nitrogen (DIN) and chemical oxygen demand (COD) in spring, COD in summer, pH in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis (CA) based on key environmental variables.

  1. Spatial segregation of the endemic versus non-endemic hummingbird on Robinson Crusoe Island, Chile

    DEFF Research Database (Denmark)

    Vizentin-Bugoni, Jeferson; Sonne, Jesper; Hodum, Peter

    2017-01-01

    Competitive pressure from invasive species tends to have a particularly strong impact on remote islands, and knowledge of such phenomena can be crucial to the conservation of endemic biodiversity. Of the two hummingbird species inhabiting Robinson Crusoe Island, Juan Fernández Archipelago, Chile...

  2. How near, how far? Adaptive radiation in mammals and birds on various islands

    NARCIS (Netherlands)

    Hoek Ostende, van den L.W.; Locatelli, E.; Meijer, H.J.M.

    2011-01-01

    Many factors control radiations on islands, but some general patterns do emerge. Bird radiations are mostly found on oceanic archipelagos far from the continental coast line. Mammal radiations are mostly know from island arcs, which are somewhat easier to reach though still isolated enough to allow

  3. Vascular plants from the Galápagos Islands: new records and taxonomic notes

    NARCIS (Netherlands)

    Werff, van der Henk

    1977-01-01

    From April 1974 to October 1975 the author conducted field work on the Galápagos Islands for a vegetation study of Santa Cruz and Volcán Alcedo, Isabela. Plants were collected on other islands as well. Thirty-five taxa are new for the archipelago. When determining the material, I found some changes

  4. Boring sponges (Porifera, Clionidae) collected during the "Tydeman" Canary Islands expedition Cancap-II, 1977

    NARCIS (Netherlands)

    Groot, de R.A.

    1980-01-01

    INTRODUCTION AND MATERIAL The boring sponges of the Canary Islands have never been studied in any detail, but the boring fauna of this archipelago cannot be expected to be very rich. All islands are volcanic and calcareous rocks are not common. Consequently, in most areas large shells and rhodophyte

  5. A first contribution to our knowledge of the flora of the Talaud Islands and Morotai

    NARCIS (Netherlands)

    Holthuis, L.B.; Lam, H.J.

    1942-01-01

    The Talaud Islands are forming part of the Malay Archipelago, being situated north of Celebes and the Moluccas, south of Mindanao and east of the Sangihe group, between 3°45’ and 5°35’ N. lat. and 126°32’ and 127°10’ E. long. The main group consists of three larger islands, viz. Karakelong, Salebabo

  6. Moss-inhabiting diatom communities from Heard Island, sub-Antarctic

    NARCIS (Netherlands)

    VandeVijver, B.; Beyens, L.; Vincke, S.; Gremmen, N.J.M.

    2004-01-01

    In this paper, we list 192 diatom taxa, collected from bryophyte samples from Heard Island (52degrees05'S, 73degrees30'E). The Heard Island diatom flora shows a marked similarity to those of the Crozet and Kerguelen archipelagos, and is quite dissimilar to the moss-dwelling diatom flora of Macquarie

  7. Geodetic implications on block formation and geodynamic domains in the South Shetland Islands, Antarctic Peninsula

    Science.gov (United States)

    Berrocoso, M.; Fernández-Ros, A.; Prates, G.; García, A.; Kraus, S.

    2016-01-01

    The South Shetland Islands archipelago is dynamically complex due to its tectonic surroundings. Most islands are part of a formerly active volcanic arc, although Deception, Penguin and Bridgeman Islands, as well as several submarine volcanoes, are characterized by active back-arc volcanism. Geodetic benchmarks were deployed and the movement of the lithosphere to which they were fixed measured to provide geodynamic insight for the South Shetland Islands, Bransfield Basin and Antarctic Peninsula area based on surface deformation. These benchmarks' data add spatial and temporal coverage to previous results. The results reveal two different geodynamic patterns, each confined to a distinct part of the South Shetland Islands archipelago. The inferred absolute horizontal velocity vectors for the benchmarks in the northeastern part of the archipelago are consistent with the opening of the Bransfield Basin, while benchmark vectors in the southwestern part of the archipelago are similar to those of the benchmarks on the Antarctic Peninsula. In between, Snow, Deception and Livingston Islands represent a transition zone. In this area, the horizontal velocity vectors relative to the Antarctic plate shift northeastwards from N to NW. Furthermore, the South Shetland Islands benchmarks, except for that at Gibbs (Elephant) Islands, indicate subsidence, which might be a consequence of the slab roll-back at the South Shetland Trench. In contrast, the uplift revealed by the Antarctic Peninsula benchmarks suggests glacial isostatic adjustment after the Larson B ice-shelf breakup.

  8. How near, how far? Adaptive radiation in mammals and birds on various islands

    NARCIS (Netherlands)

    Hoek Ostende, van den L.W.; Locatelli, E.; Meijer, H.J.M.

    2011-01-01

    Many factors control radiations on islands, but some general patterns do emerge. Bird radiations are mostly found on oceanic archipelagos far from the continental coast line. Mammal radiations are mostly know from island arcs, which are somewhat easier to reach though still isolated enough to allow

  9. A new conceptual model for aeolian transport rates on beaches

    OpenAIRE

    de Vries, S.; Stive, M.J.F.; van Rijn, L.; Ranasinghe, R.

    2012-01-01

    In this paper a new conceptual model for aeolian sediment transport rates is presented. Traditional sediment transport formulations have known limitations when applied to coastal beach situations. A linear model for sediment transport rates with respect to wind speed is proposed and supported by both data and numerical model simulations. The presented model does not solve complex wind fields and is therefore very easily applicable. Physical principles such as the presence of a threshold veloc...

  10. Soil Response to Aeolian Disturbance in West Greenland

    Science.gov (United States)

    Heindel, R. C.; Culler, L. E.; Chipman, J. W.; Virginia, R. A.

    2015-12-01

    Arctic soils are a critical ecological resource, yet are increasingly vulnerable to global change. In the Kangerlussuaq region of West Greenland, aeolian disturbance is the greatest threat to soil stability, with strong katabatic winds eroding vegetation and soil down to the underlying glacial till or bedrock. Little is known about what controls the distribution and rate of the aeolian erosion, which initially results in a state change from tundra to a deflated and nearly unvegetated ground. It is unclear if vegetation can eventually reestablish after erosion occurs, potentially aided by the biological soil crust (BSC) that develops within the eroded areas, or if this soil loss is an irreversible change in vegetation and soil carbon (C) and nitrogen (N) cycling. Our analysis of high-resolution satellite imagery shows that across the entire study region, deflated ground covers 22% of the terrestrial landscape. Aeolian erosion occurs more frequently closer to the Greenland Ice Sheet and on S-facing slopes. Using lichenometry, we estimate that erosional fronts move across the landscape at rates of 2.5 cm yr-1, leaving unproductive ground in their wake. The onset of widespread aeolian erosion occurred roughly 700-1000 years ago, pointing toward regional cooling and aridity as the drivers behind erosion. Finally, we consider whether the BSCs can improve soil quality enough to allow for full vegetation regrowth. Preliminary results show that while the BSCs fix atmospheric N and increase C storage, the rate of soil quality recovery is extremely slow. Understanding the thresholds between vegetated tundra and eroded ground is critical for predicting how the Kangerlussuaq landscape will respond to anticipated changes in climate and ice sheet dynamics.

  11. Divergent genetic strata in five Bahamian islands.

    Science.gov (United States)

    Simms, Tanya M; Barrett, Dianne A; McCartney, Quinn; Herrera, Rene J

    2012-01-01

    Based on historical records, the genetic landscape of the Bahamian archipelago is presumed to be complex and to exhibit island-specific characteristics, yet the genetic composition of the island chain, which could corroborate or refute these past accounts, remains poorly defined. As such, the current investigation was undertaken to genetically characterize 5 Bahamian populations representing the Northwest (Grand Bahama and Abaco) and Central (Eleuthera, Exuma and Long Island) Bahamas across the 15 autosomal Identifiler loci routinely employed in forensic analyses. Altogether, our findings suggest that Bahamians are a genetically heterogeneous group, with each island sampled receiving differential contributions from African, European, East Asian and Native American sources. Even though the strongest genetic signal in all 5 collections emanates from continental Africa, inter-island differentiation is noted in both the Structure and admixture analyses. The presence of alleles not in common among the 5 insular populations also signals genetic heterogeneity among the islands of the archipelago. This is especially the case when considering the Long Island population, which exhibits statistically significant genetic differences in relation to the other Bahamian collections and the New World groups of African descent (Afro-American and Afro-Caribbean) in the G-test pair-wise comparisons, even after application of the Bonferroni adjustment. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Quantifying the provenance of aeolian sediments using multiple composite fingerprints

    Science.gov (United States)

    Liu, Benli; Niu, Qinghe; Qu, Jianjun; Zu, Ruiping

    2016-09-01

    We introduce a new fingerprinting method that uses multiple composite fingerprints for studies of aeolian sediment provenance. We used this method to quantify the provenance of sediments on both sides of the Qinghai-Tibetan Railway (QTR) in the Cuona Lake section of the Tibetan Plateau (TP), in an environment characterized by aeolian and fluvial interactions. The method involves repeatedly solving a linear mixing model based on mass conservation; the model is not limited to spatial scale or transport types and uses all the tracer groups that passed the range check, Kruskal-Wallis H-test, and a strict analytical solution screening. The proportional estimates that result from using different composite fingerprints are highly variable; however, the average of these fingerprints has a greater accuracy and certainty than any single fingerprint. The results show that sand from the lake beach, hilly surface, and gullies contribute, respectively, 48%, 31% and 21% to the western railway sediments and 43%, 33% and 24% to the eastern railway sediments. The difference between contributions from various sources on either side of the railway, which may increase in the future, was clearly related to variations in local transport characteristics, a conclusion that is supported by grain size analysis. The construction of the QTR changed the local cycling of materials, and the difference in provenance between the sediments that are separated by the railway reflects the changed sedimentary conditions on either side of the railway. The effectiveness of this method suggests that it will be useful in other studies of aeolian sediments.

  13. Aeolian Sediment Transport Integration in General Stratigraphic Forward Modeling

    Directory of Open Access Journals (Sweden)

    T. Salles

    2011-01-01

    Full Text Available A large number of numerical models have been developed to simulate the physical processes involved in saltation, and, recently to investigate the interaction between soil vegetation cover and aeolian transport. These models are generally constrained to saltation of monodisperse particles while natural saltation occurs over mixed soils. We present a three-dimensional numerical model of steady-state saltation that can simulate aeolian erosion, transport and deposition for unvegetated mixed soils. Our model simulates the motion of saltating particles using a cellular automata algorithm. A simple set of rules is used and takes into account an erosion formula, a transport model, a wind exposition function, and an avalanching process. The model is coupled to the stratigraphic forward model Sedsim that accounts for a larger number of geological processes. The numerical model predicts a wide range of typical dune shapes, which have qualitative correspondence to real systems. The model reproduces the internal structure and composition of the resulting aeolian deposits. It shows the complex formation of dune systems with cross-bedding strata development, bounding surfaces overlaid by fine sediment and inverse grading deposits. We aim to use it to simulate the complex interactions between different sediment transport processes and their resulting geological morphologies.

  14. Atmospheric significance of aeolian salts in the sandy deserts of northwestern China

    Directory of Open Access Journals (Sweden)

    B.-Q. Zhu

    2015-12-01

    Full Text Available Large sandy deserts in the middle latitudes of northwestern China were investigated for soluble salt variations in modern and ancient aeolian sediments, aiming to explore the environmental significance of "aeolian salts". Results revealed that aeolian salt variations have a clear relationship with the changing meridional and zonal gradients of the desert locations and the aeolian differentiation effect, but are weakly linked to local geological conditions. It suggests that the natural system of aeolian salts is hydrologically open and the chemistry of the parent brines are different from that predicted for hydrologically closed systems. Atmospheric depositions of water-soluble chemical species are an important process/source contributing to aeolian salt. Sequential variations of soluble salts in sedimentary profiles interbedded with aeolian and non-aeolian deposits and their palaeoenvironmental implications in the hinterland areas of these deserts were further evaluated, based on the constraints of OSL dating and radiocarbon dating data. The results indicate that the inorganic salts may be a latent geoproxy in revealing regional palaeoclimatic changes in desert areas for the sediments deposited under onefold depositional environment, but the interpretation should be more careful for the sediments deposited under diverse depositional conditions. This study presents the evidence of atmospheric origin of aeolian salt in sandy deserts, with limited climatic significance in palaeoenvironmental reconstruction.

  15. Aeolian particle transport inferred using a ~150-year sediment record from Sayram Lake, arid northwest China

    Directory of Open Access Journals (Sweden)

    Long Ma

    2015-05-01

    Full Text Available We studied sediment cores from Sayram Lake in the Tianshan Mountains of northwest China to evaluate variations in aeolian transport processes over the past ~150 years. Using an end-member modeling algorithm of particle size data, we interpreted end members with a strong bimodal distribution as having been transported by aeolian processes, whereas other end members were interpreted to have been transported by fluvial processes. The aeolian fraction accounted for an average of 27% of the terrigenous components in the core. We used the ratio of aeolian to fluvial content in the Sayram Lake sediments as an index of past intensity of aeolian transport in the Tianshan Mountains. During the interval 1910-1930, the index was high, reflecting the fact that dry climate provided optimal conditions for aeolian dust transport. From 1930-1980, the intensity of aeolian transport was weak. From the 1980s to the 2000s, aeolian transport to Sayram Lake increased. Although climate in northwest China became more humid in the mid-1980s, human activity had by that time altered the impact of climate on the landscape, leading to enhanced surface erosion, which provided more transportable material for dust storms. Comparison of the Lake Sayram sediment record with sediment records from other lakes in the region indicates synchronous intervals of enhanced aeolian transport from 1910 to 1930 and 1980 to 2000.

  16. Holocene palaeosols and aeolian activities in the Umimmalissuaq valley, West Greenland

    DEFF Research Database (Denmark)

    Müller, Michael; Thiel, Christine; Kühn, Peter

    2016-01-01

    Aeolian sand sheets and active dunefields preserve an ancient Holocene land surface represented by palaeosols that occur around the present ice margin in the Kangerlussuaq area, West Greenland. To determine the relation between Holocene aeolian activities and periods of soil formation, both subst....... This period was characterised by low but constant aeolian activity. Since aeolian activity intensified after around 300 cal. yr b2k and is still resulting in active dunefields with coarse and medium sand accumulation, the ice margin must have reached its present position at that time....

  17. Mega-ripples in Iran: A new analog for transverse aeolian ridges on Mars

    Science.gov (United States)

    Foroutan, M.; Zimbelman, J. R.

    2016-08-01

    A new terrestrial analog site for transverse aeolian ridges (TARs) is described in this study. The Lut desert of Iran hosts large ripple-like aeolian bedforms, with the same horizontal length scales and patterns of TARs on Mars. Different classes of TARs and different types of other aeolian features such as sand dunes, zibars, dust devil tracks and yardangs can be found in this area, which signify an active aeolian region. This area represents a unique site to study the formation and evolution of these enigmatic features, with potential relevance toward a better understanding of TARs on Mars.

  18. Origin and in situ diversification in Hemidactylus geckos of the Socotra Archipelago.

    Science.gov (United States)

    Gómez-Díaz, Elena; Sindaco, Roberto; Pupin, Fabio; Fasola, Mauro; Carranza, Salvador

    2012-08-01

    The Socotra Archipelago is an ancient continental fragment of Gondwanan origin and one of the most isolated landforms on Earth and a biodiversity hot spot. Yet, the biogeography and evolutionary history of its endemic fauna still remain largely overlooked. We investigate the origin, tempo and mode of diversification in the Hemidactylus geckos of the Socotra Archipelago. Concatenated and multilocus species coalescent analyses of Hemidactylus from Arabia and North Africa indicate that the Hemidactylus from Socotra do not form a monophyletic group and branch as three independent and well-supported clades instead. Both the chronogram inferred using the gene tree approach of BEAST and the age-calibrated multilocus species tree obtained using *BEAST suggest that the origin of Hemidactylus from Socotra may have involved a first vicariance event that occurred in the Early Miocene, followed by two independent transoceanic dispersal events that occurred more recently, during the Pliocene. Within Socotra, we analysed patterns of genetic diversity, the phylogeography and the demographic history in all seven nonintroduced species of Hemidactylus. Results based on two mitochondrial and two nuclear loci from 144 individuals revealed complex patterns of within-island diversification and high levels of intra-species genetic divergence. The interplay of both historical and ecological factors seems to have a role in the speciation process of this group of geckos. Interestingly, the case of H. forbesii and H. oxyrhinus, which inhabit the island of Abd al Kuri with an area of 133 km(2), may represent one of the most extreme cases of intra-island speciation in reptiles ever reported. © 2012 Blackwell Publishing Ltd.

  19. Pollinating fig wasps: genetic consequences of island recolonization

    NARCIS (Netherlands)

    Zavodna, M.; Arens, P.; Partomihardjo, T.; Vosman, B.; van Dijk, P.J.; Van Damme, J.M.M.

    2005-01-01

    The levels of genetic diversity and gene flow may influence the long-term persistence of populations. Using microsatellite markers, we investigated genetic diversity and genetic differentiation in island (Krakatau archipelago, Indonesia) and mainland (Java and Sumatra, Indonesia) populations of Lipo

  20. On two Mammals from the Calamianes-islands

    NARCIS (Netherlands)

    Jentink, F.A.

    1895-01-01

    The study of the geographical distribution of the Mammals over the islands of the Malayan Archipelago teaches us the fact that only a very small number of species is common to Sumatra and Borneo and at the same time to Java. The most interesting species among them is without question Mydaus meliceps

  1. Monte Carlo path sampling approach to modeling aeolian sediment transport

    Science.gov (United States)

    Hardin, E. J.; Mitasova, H.; Mitas, L.

    2011-12-01

    Coastal communities and vital infrastructure are subject to coastal hazards including storm surge and hurricanes. Coastal dunes offer protection by acting as natural barriers from waves and storm surge. During storms, these landforms and their protective function can erode; however, they can also erode even in the absence of storms due to daily wind and waves. Costly and often controversial beach nourishment and coastal construction projects are common erosion mitigation practices. With a more complete understanding of coastal morphology, the efficacy and consequences of anthropogenic activities could be better predicted. Currently, the research on coastal landscape evolution is focused on waves and storm surge, while only limited effort is devoted to understanding aeolian forces. Aeolian transport occurs when the wind supplies a shear stress that exceeds a critical value, consequently ejecting sand grains into the air. If the grains are too heavy to be suspended, they fall back to the grain bed where the collision ejects more grains. This is called saltation and is the salient process by which sand mass is transported. The shear stress required to dislodge grains is related to turbulent air speed. Subsequently, as sand mass is injected into the air, the wind loses speed along with its ability to eject more grains. In this way, the flux of saltating grains is itself influenced by the flux of saltating grains and aeolian transport becomes nonlinear. Aeolian sediment transport is difficult to study experimentally for reasons arising from the orders of magnitude difference between grain size and dune size. It is difficult to study theoretically because aeolian transport is highly nonlinear especially over complex landscapes. Current computational approaches have limitations as well; single grain models are mathematically simple but are computationally intractable even with modern computing power whereas cellular automota-based approaches are computationally efficient

  2. Reef Fish Dispersal in the Hawaiian Archipelago: Comparative Phylogeography of Three Endemic Damselfishes

    Directory of Open Access Journals (Sweden)

    Kimberly A. Tenggardjaja

    2016-01-01

    Full Text Available Endemic marine species at remote oceanic islands provide opportunities to investigate the proposed correlation between range size and dispersal ability. Because these species have restricted geographic ranges, it is assumed that they have limited dispersal ability, which consequently would be reflected in high population genetic structure. To assess this relationship at a small scale and to determine if it may be related to specific reef fish families, here we employ a phylogeographic survey of three endemic Hawaiian damselfishes: Abudefduf abdominalis, Chromis ovalis, and Chromis verater. Data from mitochondrial markers cytochrome b and control region revealed low but significant genetic structure in all three species. Combining these results with data from a previous study on Dascyllus albisella and Stegastes marginatus, all five endemic damselfish species surveyed to date show evidence of genetic structure, in contrast with other widespread reef fish species that lack structure within the Hawaiian Archipelago. Though individual patterns of connectivity varied, these five species showed a trend of limited connectivity between the atolls and low-lying Northwestern Hawaiian Islands versus the montane Main Hawaiian Islands, indicating that, at least for damselfishes, the protected reefs of the uninhabited northwest will not replenish depleted reefs in the populated Main Hawaiian Islands.

  3. Genome-wide SNP analysis explains coral diversity and recovery in the Ryukyu Archipelago.

    Science.gov (United States)

    Shinzato, Chuya; Mungpakdee, Sutada; Arakaki, Nana; Satoh, Noriyuki

    2015-12-10

    Following a global coral bleaching event in 1998, Acropora corals surrounding most of Okinawa island (OI) were devastated, although they are now gradually recovering. In contrast, the Kerama Islands (KIs) only 30 km west of OI, have continuously hosted a great variety of healthy corals. Taking advantage of the decoded Acropora digitifera genome and using genome-wide SNP analyses, we clarified Acropora population structure in the southern Ryukyu Archipelago (sRA). Despite small genetic distances, we identified distinct clusters corresponding to specific island groups, suggesting infrequent long-distance dispersal within the sRA. Although the KIs were believed to supply coral larvae to OI, admixture analyses showed that such dispersal is much more limited than previously realized, indicating independent recovery of OI coral populations and the necessity of local conservation efforts for each region. We detected strong historical migration from the Yaeyama Islands (YIs) to OI, and suggest that the YIs are the original source of OI corals. In addition, migration edges to the KIs suggest that they are a historical sink population in the sRA, resulting in high diversity. This population genomics study provides the highest resolution data to date regarding coral population structure and history.

  4. Crustal and upper mantle seismic structure of the Svalbard Archipelago from the receiver function analysis

    Directory of Open Access Journals (Sweden)

    Wilde−Piórko Monika

    2015-06-01

    Full Text Available Receiver function provides the signature of sharp seismic discontinuities and the information about the shear wave (S−wave velocity distribution beneath the seismic station. This information is very valuable in areas where any or few reflection and/or refraction studies are available and global and/or regional models give only rough information about the seismic velocities. The data recorded by broadband seismic stations have been analysed to investigate the crustal and upper mantle structure of the Svalbard Archipelago. Svalbard Archipelago is a group of islands located in Arctic, at the north−western part of the Barents Sea continental platform, which is bordered to the west and to the north by passive continental margins. The new procedure of parameterization and selection of receiver functions (RFs has been proposed. The back−azimuthal sections of RF show a strong variation for the HSPB and KBS stations. Significant amplitudes of transversal component of RF (T−RF for the HSPB station indicate a shallow dipping layer towards the southwest. The structure of the crust beneath the SPITS array seems to be less heterogeneous, with very low amplitudes of converted phase comparing to the KBS and HSPB stations. Forward modelling by trial−and−error method shows a division of the crust into 3-4 layers beneath all stations and layering of the uppermost mantle beneath the SPITS array and the HSPB stations. The thickness of the mantle transition zone is larger for western part of archipelago and smaller for eastern part comparing to iasp91 model.

  5. Status of the Coral Reefs of the Samoan Archipelago

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of this study are twofold: (1) To determine the current status of coral reef fishes and their habitat throughout the Samoan Archipelago. This will be...

  6. Sponge beta diversity in the Spermonde Archipelago, SW Sulawesi, Indonesia

    NARCIS (Netherlands)

    Voogd, de N.J.; Cleary, D.F.R.; Hoeksema, B.W.; Noor, A.; Soest, van R.W.M.

    2006-01-01

    Sponge assemblages were investigated in the Spermonde Archipelago, southwestern Sulawesi, Indonesia. In this study spatial patterns of sponge similarity among sites were significantly related to remotely sensed environmental variables, the degree of human settlement and depth, but not to the

  7. Biodiversity conservation and utilisation in the Maltese Islands

    OpenAIRE

    Stevens, D. T.; Lanfranco, Edwin; Mallia, Adrian; Schembri, Patrick J.; Commonwealth Science Council Conference on Identifying and Monitoring Biodiversity and its Utilization in Commonwealth Small Island Developing States

    1995-01-01

    The Maltese archipelago which occupies an area of c.316km2 consists of the inhabited islands of Malta, Gozo and Comino and several other uninhabited islets and rocks. In spite of their restricted area, the limited number of habitats, and the intense human pressure, the Maltese Islands support a very diverse terrestrial and freshwater biota, with some 2000 species of plants and fungi known, more than 4000 species of insects, several hundred species of other invertebrates, and more than 200 ter...

  8. Wine, tourism and experience in the Canary Islands' context

    OpenAIRE

    Alonso, Abel Duarte

    2009-01-01

    The Canary Islands or ‘fortunate islands,’ a Spanish archipelago and a well-known mass tourism destination, is experiencing the redevelopment of its wine industry. In this regard, wine tourism appears to be a natural extension emerging from a traditional product - wine - that has been part of Canary Islands’ culture for centuries. This study explores the extent to which wine, tourism and related experiences are becoming integrated in local wineries’ business/marketing concept. Semi-structured...

  9. Oceanographic mechanisms that possibly explain dominance of neritic-tropical zooplankton species assemblages around the Islas Marías Archipelago, Mexico

    OpenAIRE

    Jaime Gómez-Gutiérrez; René Funes-Rodríguez; Karmina Arroyo-Ramírez; Carlos Armando Sánchez-Ortíz; Juan Ramón Beltrán-Castro; Sergio Hernández-Trujillo; Ricardo Palomares-García; Octavio Aburto-Oropeza; Exequiel Ezcurra

    2014-01-01

    The nearshore zooplankton species assemblage, identified per taxonomic groups (20) and per species for 12 selected groups, was analyzed from samples collected during November 2010 at four volcanic islands of the Islas Marías Archipelago (IMA), located 90-120 km offshore Nayarit, Mexico. From chlorophyll-a concentration and zooplankton biovolume perspective mesotrophic conditions prevailed in comparison with the Gulf of California during November. Crustaceans numerically dominated the zooplank...

  10. Postglacial formation and dynamics of North Patagonian Rainforest in the Chonos Archipelago, Southern Chile

    Science.gov (United States)

    Haberle, S. G.; Bennett, K. D.

    2004-12-01

    Pollen analysis of continuous sediment cores from two lakes in the northern Chonos Archipelago (44°S) in southern Chile shows a complete postglacial record of vegetation change. The fossil records indicate that deglaciation was complete in the northern Chonos by at least 13,600 14C yr BP. Ericaceous heath and grassland persisted for more than 600 years after deglaciation under the influence of dry/cold climates and frequent burning. Nothofagus- Pilgerodendron- Podocarpus forest, with modern analogues in the southern Chonos Archipelago, was established across the northern islands by 12,400 14C yr BP under increasingly warm and wet climates. There is no evidence for a return to cooler climates during the Younger Dryas chronozone. The rise of Tepualia stipularis and Weinmannia trichosperma as important forest components between 10,600 and 6000 14C yr BP may be associated with climates that were warmer than present. The collapse of Pilgerodendron communities during this time may have been triggered by a combination of factors related to disturbance frequency including tephra deposition events, fire and climate change. After 6000 14C yr BP Pilgerodendron recovers and Nothofagus-Pilgerodendron-Tepualia forest persists until the present. European logging and burning activity may have increased the susceptibility of North Patagonian Rainforest to invasion by introduced species and to future collapse of the long-lived Pilgerodendron communities.

  11. The groundwater invertebrate fauna of the Channel Islands

    Directory of Open Access Journals (Sweden)

    Lee R.F.D. Knight

    2015-05-01

    Full Text Available The Channel Islands are a small archipelago of British dependencies just off the coast of Normandy at the western end of the English Channel. There were only three records for stygobitic Crustacea [Niphargus fontanus Bate, 1859 and N. kochianus Bate, 1859 from Jersey and N. aquilex Schiődte, 1855 from Guernsey] from the archipelago and no systematic survey has been carried out of the islands for their groundwater fauna till present. Recently sampling was carried out in wells, boreholes and springs on the four largest islands, Jersey, Guernsey, Alderney and Sark during February 2012. Niphargus aquilex was widespread across all four islands and did not appear to be restricted to any particular geology. Niphargus ladmiraulti was present in large numbers in a single borehole on Jersey, the first record of this species from the archipelago. Niphargus kochianus was collected from two sites on Alderney and the syncarid Antrobathynella stammeri (Jakobi, 1954 from two sites on the west coast of Jersey. The records for A. stammeri are new for the Channel Islands and possibly represent the first records of this species from the French bio-geographical area. The presence of N. fontanus on the islands was not confirmed. Several species of stygophilic Cyclopoida were also recorded during the survey along with epigean freshwater invertebrate taxa, which were mostly present in springs and shallow wells close to surface streams.

  12. Sand incursion into temperate (Lithuania) and tropical (the Bahamas) maritime vegetation: Georadar visualization of target-rich aeolian lithosomes

    Science.gov (United States)

    Buynevich, Ilya V.; Savarese, Michael; Curran, H. Allen; Bitinas, Albertas; Glumac, Bosiljka; Pupienis, Donatas; Kopcznski, Karen; Dobrotin, Nikita; Gnivecki, Perry; Boush, Lisa Park; Damušytė, Aldona

    2017-08-01

    Interaction of windblown sand with maritime vegetation, either as dune migration or episodic grain transport is a common phenomenon along many sandy coasts. Vegetation introduces antecedent surface roughness, especially when scaled to the landform height, but its role may be concealed if overwhelmed by aeolian incursion and burial. Where field observations and cores lack detail for characterizing this complex process, ground-penetrating radar (GPR) offers continuous visualization of aeolian sequences. Along the Curonian Spit, Lithuania, dune reactivation phases resulted in massive invasion of siliciclastic sand triggered by natural perturbations and land clearance. Massive (>30 m high) dunes entombed mature pine, oak, and alder stands and this process is ongoing. Mid-frequency (200 MHz) georadar surveys reveal landward-dipping lateral accretion surfaces interrupted by high-amplitude point-source anomalies produced by recently buried trees. In tropical regions, dense vegetation and potential for rapid lithification of carbonate sand results in more complex internal structures. Along the windward coast of San Salvador Island, the Bahamas, a massive dune has buried several generations of maritime scrubland, resulting in highly chaotic reflection pattern and high target density. On a nearby Little Exuma Island, numerous reentrants in aeolianites promoted formation of blowouts and incursion of windblown sand 10-25 m into a silver thatch palm forest. High-frequency (800 MHz) GPR images resolve diffractions from trunks and roots buried by > 2 m of oolitic sand. Basal refection morphology helps differentiate the irregular dune/beachrock surface from a smooth palm-frond mat. Aside from detecting and mapping buried vegetation, geophysical images capture its effect on sediment accumulation. This has the potential for differentiating its effect from other discordant structures within dunes (clasts, dissolution voids, trunk molds, burrows, and cultural remains).

  13. Continued monitoring of aeolian activity within Herschel Crater, Mars

    Science.gov (United States)

    Cardinale, Marco; Pozzobon, Riccardo; Michaels, Timothy; Bourke, Mary C.; Okubo, Chris H.; Chiara Tangari, Anna; Marinangeli, Lucia

    2017-04-01

    In this work, we study a dark dune field on the western side of Herschel crater, a 300 km diameter impact basin located near the Martian equator (14.4°S, 130°E), where the ripple and dune motion reflects the actual atmospheric wind conditions. We develop an integrated analysis using (1) automated ripple mapping that yields ripple orientations and evaluates the spatial variation of actual atmospheric wind conditions within the dunes, (2) an optical cross-correlation that allows us to quantify an average ripple migration rate of 0.42 m per Mars year, and (3) mesoscale climate modeling with which we compare the observed aeolian changes with modeled wind stresses and directions. Our observations are consistent with previous work [1] [2] that detected aeolian activity in the western part of the crater. It also demonstrates that not only are the westerly Herschel dunes movable, but that predominant winds from the north are able to keep the ripples and dunes active within most (if not all) of Herschel crater in the current atmospheric conditions. References: [1] Cardinale, M., Silvestro, S., Vaz, D.A., Michaels, T., Bourke, M.C., Komatsu, G., Marinangeli, L., 2016. Present-day aeolian activity in Herschel Crater, Mars. Icarus 265, 139-148. doi:10.1016/j.icarus.2015.10.022. [2] Runyon, K.D., Bridges, N.T., Ayoub, F., Newman, C.E. and Quade, J.J., 2017. An integrated model for dune morphology and sand fluxes on Mars. Earth and Planetary Science Letters, 457, pp.204-212.

  14. The Icelandic volcanic aeolian environment: Processes and impacts - A review

    Science.gov (United States)

    Arnalds, Olafur; Dagsson-Waldhauserova, Pavla; Olafsson, Haraldur

    2016-03-01

    Iceland has the largest area of volcaniclastic sandy desert on Earth or 22,000 km2. The sand has been mostly produced by glacio-fluvial processes, leaving behind fine-grained unstable sediments which are later re-distributed by repeated aeolian events. Volcanic eruptions add to this pool of unstable sediments, often from subglacial eruptions. Icelandic desert surfaces are divided into sand fields, sandy lavas and sandy lag gravel, each with separate aeolian surface characteristics such as threshold velocities. Storms are frequent due to Iceland's location on the North Atlantic Storm track. Dry winds occur on the leeward sides of mountains and glaciers, in spite of the high moisture content of the Atlantic cyclones. Surface winds often move hundreds to more than 1000 kg m-1 per annum, and more than 10,000 kg m-1 have been measured in a single storm. Desertification occurs when aeolian processes push sand fronts and have thus destroyed many previously fully vegetated ecosystems since the time of the settlement of Iceland in the late ninth century. There are about 135 dust events per annum, ranging from minor storms to >300,000 t of dust emitted in single storms. Dust production is on the order of 30-40 million tons annually, some traveling over 1000 km and deposited on land and sea. Dust deposited on deserts tends to be re-suspended during subsequent storms. High PM10 concentrations occur during major dust storms. They are more frequent in the wake of volcanic eruptions, such as after the Eyjafjallajökull 2010 eruption. Airborne dust affects human health, with negative effects enhanced by the tubular morphology of the grains, and the basaltic composition with its high metal content. Dust deposition on snow and glaciers intensifies melting. Moreover, the dust production probably also influences atmospheric conditions and parameters that affect climate change.

  15. A comprehensive method for aeolian particle granulometry and micromorphology analyses.

    Science.gov (United States)

    Zaady, E; Dody, A; Weiner, D; Barkai, D; Offer, Z Y

    2009-08-01

    The aim of this study was to use a new approach to investigate aeolian particle granulometry and micromorphology. Taking total aeolian deposition into account, we used parameters such as, particle area, perimeter, shape analysis for particle roughness (area/perimeter) and elongation (long/short axis). These parameters were analyzed on temporal and spatial scales at four study sites in the eastern Negev Desert, Israel. The total collection of particles was sorted into three size groups based on particle area to facilitate comparison. The classic definition of particle size (equating particle length with particle diameter) produced relatively small variations among the three size classes (25-38.6%). Our proposed comprehensive method demonstrated significant variation among the three size classes (13.9-60.8%), e.g. the classic method placed 36.4% of the particles in size class two while the new method placed 60.8% of the particles in this size class; the differences were even more significant regarding size class 3 (38.6% vs. 13.9%, respectively). The classic method did not facilitate investigation of particle roughness and elongation. With this new approach, it was possible to clearly define the particles by size class, based on these characteristics. With roughness, the variation among size classes 2 and 3 was about 27%. With elongation, the variation among size classes two and three was about 21%. Applying similar investigation method to study the aeolian particle granulometry and micromorphology can better facilitate more detailed calculation of particle size distribution, roughness and elongation.

  16. Assesing Geographic Isolation of the Galapagos Islands

    Science.gov (United States)

    Orellana, D.; Smith, F.

    2016-06-01

    The Galapagos Archipelago is one of the most important ecological spots in the planet due its unique biodiversity, active geology, and relatively well-preserved ecosystems. These characteristics are strongly based on the geographical isolation of the islands. On the one hand this isolation allowed the evolution processes that gave the islands their international fame and on the other hand it kept them from major human impacts that affected the vast majority of the Earth's surface. Galapagos' geographical isolation is therefore of mayor value, but it is rapidly diminishing due to the increase of marine and air transportation among islands and with the rest of the world. This increased accessibility implies enhanced risks for the ecological dynamics on the archipelago (e.g. increased risk of biological invasions, uncontrolled tourism growth, more water and energy consumption). Here, we introduce a general accessibility model to assess geographical isolation of the Galapagos Islands. The model aims to characterize accessibility in terms of human mobility by evaluating travel time to each point of the archipelago using all available transportation modalities. Using a multi criteria cost surface for marine and land areas, we estimated travel time for each surface unit using the fastest route and mode of transportation available while considering several friction factors such as surface type, slope, infrastructure, transfer points, legal restrictions, and physical barriers. We created maps to evaluate the isolation of different islands and places, highlighting the potential risks for several habitats and ecosystems. The model can be used for research and decision-making regarding island conservation, such as estimating spreading paths for invasive species, informing decisions on tourism management, and monitoring isolation changes of sensitive ecosystems.

  17. Responses of aeolian desertification to a range of climate scenarios in China

    Science.gov (United States)

    Wang, Xunming; Hua, Ting; Ma, Wenyong

    2016-06-01

    Aeolian desertification plays an important role in earth-system processes and ecosystems, and has the potential to greatly impact global food production. The occurrence of aeolian desertification has traditionally been attributed to increases in wind speed and temperature and decreases in rainfall. In this study, by integrating the aeolian desertification monitoring data and climate and vegetation indices, we found that although aeolian desertification is influenced by complex climate patterns and human activities, increases in rainfall and temperature and decreases in wind speed may not be the key factors of aeolian desertification controls in some regions of China. Our results show that, even when modern technical approaches are used, different approaches to desertification need to be applied to account for regional differences. These results have important implications for future policy decisions on how best to combat desertification.

  18. An Ecological Perspective on Inshore Fisheries in the Main Hawaiian Islands

    OpenAIRE

    Smith, M. Kimberly

    1993-01-01

    A description of fisheries within a depth of 100 fathoms is provided for the eight southeastern-most islands of the Hawaiian Archipelago, known as the main Hawaiian Islands (MHI). These are the inhabited islands of the State of Hawaii and are those most subject to inshore fishing pressure, because of their accessibility. Between 1980 and 1990, an average of 1,300 short tons of fishes and invertebrates were reported annually within 100 fm by commercial fishermen. Total landings may be signific...

  19. Sailing the Archipelago in a boat of rhymes Pantun in the Malay world

    Directory of Open Access Journals (Sweden)

    Muhammad Haji Salleh

    2011-04-01

    Full Text Available The extremely popular poetic form from Insular Southeast Asia, the pantun, travelled from its unknown source throughout the Malay Archipelago, first in Malay, then in the languages of Southeast Asia. In the ports and states where they were received, local colour, other idiosyncrasies, references, and linguistic characteristics have been added, and in fact, special forms with special names developed. This basic form is known, composed, and loved in at least 40 dialects of Malay, and 35 non-Malay languages, in the Peninsula and many of the islands of Malaysia and Indonesia. It spread through trade routes, ports, and also via diasporas and colonial economic projects which caused numerous peoples to move, who in turn brought the pantun along with them. It is now the most dynamic single literary form and has the longest history.

  20. Potential speciation of morphotypes in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago, Japan

    Science.gov (United States)

    Hirose, M.; Yokobori, S.; Hirose, E.

    2009-03-01

    Four morphotypes are recognized in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago: three color morphs (white, dark gray, and brown) of small-type colonies and one large-type colony (white with gray patches). The genetic variation among these four morphotypes was investigated by constructing phylogenetic trees based on a 401-bp fragment of the cytochrome oxidase subunit I (COI) gene of 29 specimens collected from five islands (Okinawajima, Sesokojima, Ikeijima, Kumejima, and Ishigakijima). The results support the monophyly of the genus Didemnum and that of the four morphotypes of D. molle. Moreover, the phylogenetic trees discriminated four clades corresponding to each morphotype. The geographic differences of the sequences were much smaller than the differences among the morphotypes, suggesting that the four morphotypes in D. molle are discrete sibling species.

  1. Functional analysis of the newly established plants induced by nesting gulls on Riou archipelago (Marseille, France)

    Science.gov (United States)

    Vidal, Eric; Médail, Frédéric; Tatoni, Thierry; Vidal, Patrick; Roche, Philip

    1998-06-01

    The recent population explosion of Yellow-legged gulls ( Larus cachinnans), nesting on the Riou archipelago, off Marseille (France), has perturbed the flora and the vegetation of this site. The present study consists of a functional approach to the newly established plant species through an analysis of some of their vital attributes. Small islets appear to be more affected by floristic turnover than larger islands. In some cases, more than 50 % of the current flora was not present 35 years ago. The newly established taxa show special adaptations to the severe ecological pressure induced by gull colonies and to the characteristics of the Mediterranean climate. These plant species are mostly therophytes or hemicryptophytes and have a ruderal or a stress-tolerant strategy. Gulls' contribution to propagule dispersal from the continent appears to be very slight, dispersal by wind being the prevalent mode.

  2. Transient magmatic control in a tectonic domain: the central Aeolian volcanic arc (South Italy)

    KAUST Repository

    Ruch, Joel

    2015-04-01

    The background stress field in volcanic areas may be overprinted by that produced by transient magmatic intrusions, generating local faulting. These events are rarely monitored and thus not fully understood, generating debate about the role of magma and tectonics in any geodynamic setting. Here we carried out a field structural analysis on the NNW-SSE strike-slip system of the central Aeolian Arc, Italy (Lipari and Vulcano islands) with ages constrained by stratigraphy to better capture the tectonic and magmatic evolution at the local and regional scales. We consider both islands as a single magmatic system and define 5 principal stratigraphic units based on magmatic and tectonic activity. We collected >500 measurements of faults, extension fractures and dikes at 40 sites, mostly NNE-SSW to NNW-SSE oriented with a dominant NS orientation. These structures are governed quasi exclusively by pure dip-slip motion, consistent with an E-W extension direction, with minor dextral and sinistral slip, the latter being mostly related to old deposits (>50 ka). We further reconstructed the evolution of the Vulcano-Lipari system during the last ~20 ka and find that it consists of an overall half-graben-like structure, with faults with predominant eastward dips. Field evidence suggests that faulting occurs often in temporal and spatial relation with magmatic events, suggesting that most of the observable deformation derived from transient magmatic activity, rather than from steady regional tectonics. To explain the dominant magmatic and episodic extension in a tectonic dominant domain, we propose a model where the regional N-S trending maximum horizontal stress, responsible for strike-slip activity, locally rotates to vertical in response to transient pressurization of the magmatic system and magma rise below Lipari and Vulcano. This has possibly generated the propagation of N-S trending dikes in the past 1 ka along a 10 km long by 1 km wide crustal corridor, with important

  3. Heat Islands

    Science.gov (United States)

    EPA's Heat Island Effect Site provides information on heat islands, their impacts, mitigation strategies, related research, a directory of heat island reduction initiatives in U.S. communities, and EPA's Heat Island Reduction Program.

  4. Gully annealing by aeolian sediment: field and remote-sensing investigation of aeolian-hillslope-fluvial interactions, Colorado River corridor, Arizona, USA

    Science.gov (United States)

    Sankey, Joel B.; Draut, Amy E.

    2014-01-01

    Processes contributing to development of ephemeral gully channels are of great importance to landscapes worldwide, and particularly in dryland regions where soil loss and land degradation from gully erosion pose long-term land-management problems. Whereas gully formation has been relatively well studied, much less is known of the processes that anneal gullies and impede their growth. This study of gully annealing by aeolian sediment, spanning 95 km along the Colorado River corridor in Glen, Marble, and Grand Canyon, Arizona, USA, employed field and remote sensing observations, including digital topographic modelling. Results indicate that aeolian sediment activity can be locally effective at counteracting gully erosion. Gullies are less prevalent in areas where surficial sediment undergoes active aeolian transport, and have a greater tendency to terminate in active aeolian sand. Although not common, examples exist in the record of historical imagery of gullies that underwent infilling by aeolian sediment in past decades and evidently were effectively annealed. We thus provide new evidence for a potentially important interaction of aeolian–hillslope–fluvial processes, which could affect dryland regions substantially in ways not widely recognized. Moreover, because the biologic soil crust plays an important role in determining aeolian sand activity, and so in turn the extent of gully development, this study highlights a critical role of geomorphic–ecologic interactions in determining arid-landscape evolution.

  5. High-resolution modelling of 3D hydrodynamics in coastal archipelagos

    Science.gov (United States)

    Miettunen, Elina; Tuomi, Laura; Ropponen, Janne; Lignell, Risto

    2016-04-01

    Dynamics of the coastal seas are affected by eutrophication, over-fishing, coastal construction and climate change. To enable the sustainable development of these areas, monitoring and modelling of the state of the sea are needed. The Archipelago Sea, located in the northern part of the semi-enclosed and brackish water Baltic Sea, is one of the most complex coastal areas with over 40 000 small islands and islets. It is also very vulnerable area already heavily stressed with eutrophication. Applicable modelling tools are needed to support the decision making and to provide sufficiently reliable information on the effects of the planned actions on the state of the coastal waters. We used 3D hydrodynamic model COHERENS to model the Archipelago Sea area with high spatial resolution of 0.25 nmi. Boundary conditions for this limited area were provided from coarser resolution, 2 nmi, Baltic Sea grid. In order to evaluate the performance of the high-resolution coastal model implementation a comprehensive measurement dataset was gathered, including hydrographic data from three intensive monitoring stations and several more rarely visited monitoring or research stations. The hydrodynamic model was able to simulate the surface temperature and salinity fields and their seasonal variation with good accuracy in this complex area. The sharp depth gradients typical for this area provided some challenges to the modelling. There was some over mixing and related to too strong vertical currents in the steep slopes of the deeper fault lines. Also the water exchange between the more open sea and coastal areas through narrow channels between the islands is not sufficiently well reproduced with the current resolution, leading to too high bottom temperatures.

  6. Reproductive response to nitrogen and phosphorus fertilization along the Hawaiian archipelago's natural soil fertility gradient.

    Science.gov (United States)

    DiManno, Nicole M; Ostertag, Rebecca

    2016-01-01

    Nitrogen (N) and phosphorus (P) are the most important nutrients involved in plant reproduction and typically the most limiting in terrestrial ecosystems. The natural soil fertility gradient of the Hawaiian archipelago, in which younger islands are N limited and older islands are P limited, provides a model system to examine questions regarding allocation of nutrients. Using fertilized plots (+N or +P) at the extreme sites of the Hawaiian archipelago, vegetative productivity (e.g., net primary productivity, growth, and litterfall) and foliar nutrient responses have previously been studied for the dominant canopy tree, Metrosideros polymorpha. Here, we investigated whether the reproductive response of M. polymorpha mirrors the previously found vegetative productivity and foliar nutrient responses, by quantifying: (1) inflorescence and seed productivity, and (2) nutrient concentration of reproductive structures. Fertilization with N and P did not significantly affect the productivity of inflorescences or seeds, or seed viability at either site. However, nutrient concentrations increased after fertilization; %P increased in inflorescences in the +P treatment at the P-limited site. Seeds and inflorescences generally contained higher nutrient concentrations than leaves at both sites. Unlike foliar data, reproductive strategies of M. polymorpha differed depending on soil nutrient limitation with emphasis on quality (higher seed viability/greater nutrient concentrations) at the P-limited site. We suggest that in response to P additions M. polymorpha employs a nutrient conservation strategy for its inflorescences and an investment strategy for its seeds. Examining N and P simultaneously challenges a basic assumption that reproductive allocation follows a similar pattern to the often measured aboveground productivity.

  7. Introduced mammals on Western Indian Ocean islands

    Directory of Open Access Journals (Sweden)

    James C. Russell

    2016-04-01

    Full Text Available The diversity of introduced mammals and their introduction history varies greatly across the Western Indian Ocean (WIO islands, from ancient introductions in the past millennia on islands off the East coast of Africa where extant terrestrial native mammal communities exist, to very recent invasions in the past decades on islands in the Mascarene archipelago. We compile the distribution of 16 introduced mammal taxa on 28 island groups comprising almost 2000 islands. Through an exhaustive literature review and expert consultation process we recorded all mammal eradications, and species recoveries which could be attributed to introduced mammal eradication or control. All island groups have been invaded by mammals, and invasive cats and rats in particular are ubiquitous, but cultural contingency has also led to regional invasions by other mammals such as lemurs, civets and tenrecs. Mammal eradications have been attempted on 45 islands in the WIO, the majority in the Seychelles and Mauritius, and where successful have resulted in spectacular recovery of species and ecosystems. Invasive mammalian predator eradication or control in association with habitat management has led to improved conservation prospects for at least 24 species, and IUCN red-list down-listing of eight species, in the Mascarene Islands. Future island conservation prioritisation in the region will need to take account of global climate change and predicted sea-level rises and coastal inundation. Greater investment and prioritisation in island conservation in the region is warranted, given its high biodiversity values and the extent of invasions.

  8. Island development: Local governance under globalization

    Directory of Open Access Journals (Sweden)

    Huei-Min Tsai

    2014-12-01

    Full Text Available Issues surrounding island development have generated a growing volume of research. What does it mean to develop? How can island communities maintain control over development processes to the benefit of the local economy, rather than seeing economic flows enter and exit the island with little or a primarily negative impact? And how important is local knowledge for edifying local governance and enhancing potentials for innovation in island development? Island histories have repeatedly been forwarded as exemplars and ‘lessons’ for global learning on (unsustainability. To consider these issues, we have selected a number of papers from among the presentations given at the International Geographical Union’s Commission on Islands Conference, Island Development: Local Economy, Culture, Innovation and Sustainability, which took place in the Penghu Archipelago, Taiwan, 1–5 October 2013. These papers serve as examples of how the processes of globalization have penetrated the borders and changed the political and economic structures of islands. They also explore how island-based innovations in science, technology, culture, and formal or informal governance might contribute to sustainable island development.

  9. Spatial variation patterns of subtidal seaweed assemblages along a subtropical oceanic archipelago: Thermal gradient vs herbivore pressure

    Science.gov (United States)

    Sangil, Carlos; Sansón, Marta; Afonso-Carrillo, Julio

    2011-10-01

    The structure and composition of subtidal rocky seaweed assemblages were studied at 69 sites on the Canary Islands (northeastern Atlantic). This group of islands are situated at the southern boundary of the warm temperate region and adjacent to the cold waters from the northwest African coastal upwelling, which creates a difference of almost 2 °C in surface seawater temperature from the eastern to the western islands. This thermal variation allows an examination of the transition between the warm temperate and the tropical regions along this longitudinal gradient together with the hypothesised Fucales-dominated assemblages towards the eastern islands in contrast to the Dictyotales-dominated assemblages towards the western ones. Environmental and biological parameters were considered in order to investigate which were the main factors explaining spatial variation along the gradient in a multi-scaled approach. Although seventy-nine macroalgae were identified, 87.63% of the total mean cover was due to six taxa ( Lobophora variegata, nongeniculate corallines, Canistrocarpus cervicornis, Jania adhaerens, Cystoseira abies-marina and Pseudolithoderma adriaticum). At a large scale, sea urchin density explained the highest variation in seaweed assemblages (26.94%), and its pattern of distribution across the islands. The expected pattern of distribution according to the upwelling distance only occurred in restricted areas of the Canarian Archipelago in absence of herbivore pressure and habitat degradation. Spatial variations within islands (medium scale) were mainly related to wave exposure, while at a small scale these were mostly due to the degree of sedimentation.

  10. Islands of the Arctic

    Science.gov (United States)

    Overpeck, Jonathan

    2004-02-01

    Few environments on Earth are changing more dramatically than the Arctic. Sea ice retreat and thinning is unprecedented in the period of the satellite record. Surface air temperatures are the warmest in centuries. The biology of Arctic lakes is changing like never before in millennia. Everything is pointing to the meltdown predicted by climate model simulations for the next 100 years. At the same time, the Arctic remains one of the most pristine and beautiful places on Earth. For both those who know the Arctic and those who want to know it, this book is worth its modest price. There is much more to the Arctic than its islands, but there's little doubt that Greenland and the major northern archipelagos can serve as a great introduction to the environment and magnificence of the Arctic. The book uses the islands of the Arctic to give a good introduction to what the Arctic environment is all about. The first chapter sets the stage with an overview of the geography of the Arctic islands, and this is followed by chapters that cover many key aspects of the Arctic: the geology (origins), weather and climate, glaciers, ice sheets, sea ice, permafrost and other frozen ground issues, coasts, rivers, lakes, animals, people, and environmental impacts. The material is pitched at a level well suited for the interested layperson, but the book will also appeal to those who study the science of the Arctic.

  11. The Indonesian archipelago: an ancient genetic highway linking Asia and the Pacific.

    Science.gov (United States)

    Tumonggor, Meryanne K; Karafet, Tatiana M; Hallmark, Brian; Lansing, J Stephen; Sudoyo, Herawati; Hammer, Michael F; Cox, Murray P

    2013-03-01

    Indonesia, an island nation linking mainland Asia with the Pacific world, hosts a wide range of linguistic, ethnic and genetic diversity. Despite the complexity of this cultural environment, genetic studies in Indonesia remain surprisingly sparse. Here, we report mitochondrial DNA (mtDNA) and associated Y-chromosome diversity for the largest cohort of Indonesians examined to date-2740 individuals from 70 communities spanning 12 islands across the breadth of the Indonesian archipelago. We reconstruct 50 000 years of population movements, from mitochondrial lineages reflecting the very earliest settlers in island southeast Asia, to Neolithic population dispersals. Historic contacts from Chinese, Indians, Arabs and Europeans comprise a noticeable fraction of Y-chromosome variation, but are not reflected in the maternally inherited mtDNA. While this historic immigration favored men, patterns of genetic diversity show that women moved more widely in earlier times. However, measures of population differentiation signal that Indonesian communities are trending away from the matri- or ambilocality of early Austronesian societies toward the more common practice of patrilocal residence today. Such sex-specific dispersal patterns remain even after correcting for the different mutation rates of mtDNA and the Y chromosome. This detailed palimpsest of Indonesian genetic diversity is a direct outcome of the region's complex history of immigration, transitory migrants and populations that have endured in situ since the region's first settlement.

  12. Historical change of mercury pollution in remote Yongle archipelago, South China Sea.

    Science.gov (United States)

    Liu, Xiaodong; Xu, Liqiang; Chen, Qianqian; Sun, Liguang; Wang, Yuhong; Yan, Hong; Liu, Yi; Luo, Yuhan; Huang, Jing

    2012-04-01

    We collected three ornithogenic coral sand sedimentary profiles from Jinyin Island, Jinqing Island and Guangjin Island of Yongle archipelago, South China Sea and reconstructed the deposition flux of anthropogenic Hg over the past 700 years in the study area. On the whole, the anthropogenic Hg flux is relatively low; it remained at a low level before the Industrial Revolution with a small peak at about 1450-1550 AD, which may record the enhanced metallurgy activity in Ming Dynasty of China. During the 20th century, the deposition flux of anthropogenic Hg increased rapidly, but two troughs occurred during the periods around 1940s and 1970s, corresponding to the economic depression caused by World War II, Civil War in China (1945-1949), and the Culture Revolution (1966-1976) in China. Since the 1970s the deposition flux of anthropogenic Hg has been persistently increasing, apparently the result of fast economic development in East and Southeast Asia countries around South China Sea.

  13. Aeolian dune interactions preserved in the ancient rock record

    Science.gov (United States)

    Day, Mackenzie; Kocurek, Gary

    2017-08-01

    Interactions between individual dunes drive the evolution of a dune-field pattern. Ubiquitous in modern systems, dune interactions have increasingly been the focus in understanding dune-field dynamics through surface models and experiments. In contrast, how these dynamics are incorporated into the stratigraphic record has remained largely unaddressed. Current models for the interpretation of the architecture of sets of aeolian cross-strata and bounding surfaces do not explicitly incorporate dune interactions. Recent documentation of a common type of dune interaction and the resulting stratigraphic architecture at the White Sands Dune Field, New Mexico, has established a set of diagnostic criteria by which this architecture could be identified. In this study, five examples of interpreted interaction architecture were identified in well-known Jurassic aeolian units in the western United States. These results confirm the expected presence of dune-interaction architecture in the rock record, and highlight the need for a new generation of models that couple complex dune surface dynamics with their stratigraphic expression.

  14. Element Geochemical Analysis of the Contribution of Aeolian Sand to Suspended Sediment in Desert Stream Flash Floods

    Directory of Open Access Journals (Sweden)

    Xiaopeng Jia

    2014-01-01

    Full Text Available The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  15. Element geochemical analysis of the contribution of aeolian sand to suspended sediment in desert stream flash floods.

    Science.gov (United States)

    Jia, Xiaopeng; Wang, Haibing

    2014-01-01

    The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  16. The Gulag Archipelago: From Inferno to Paradiso

    Directory of Open Access Journals (Sweden)

    David Matual

    1982-09-01

    Full Text Available It is apparent from the title of his novel The First Circle and from various details there and in other works that Alexander Solzhenitsyn is familiar with at least the imagery of Dante's Divine Comedy . One direct and several indirect references to it also suggest a Dantean subtext in his longest and most ambitious project, The Gulag Archipelago . Indeed, the loci of the Comedy — Inferno , Purgatorio , and Paradiso —are transformed in the Gulag into metaphorical representations of the various stages in the development of man's consciousness—and especially Solzhenitsyn's consciousness—during the ordeals of arrest, inquest, imprisonment, and exile. The Inferno is surely the most prominent and in some ways the most memorable part of Solzhenitsyn's work. It is the phase in which most of the zeks live—the phase of unremitting hatred, cynicism, and selfishness caused by the cruelty and degradation of their experiences in prisons and labor camps. It is a life among rapacious thieves and police informers, a life in which only the self matters. The Purgatorio is the stage reached by those who, like Solzhenitsyn himself, begin to question the validity of all ideologies and who recognize and admire the strength of those whose personality derives from an uncompromisingly spiritual worldview. But in the Purgatorio the light of understanding is just beginning to penetrate the darkness; the process of spiritual rebirth is in an embryonic state. When a zek crosses the threshold of the Paradiso (as Solzhenitsyn clearly does—notably in Part IV, he attains a wisdom and understanding not yet accessible to the majority of men. He realizes that attachments to property, possessions, and even loved ones only add to the sufferings of the prisoners. He now knows that the life of the spirit, divorced from earthly preoccupations, is the only life that is eternal and inviolate. With that realization he has achieved the ultimate knowledge and the ultimate

  17. Risk Factors of Typhoid Infection in the Indonesian Archipelago.

    Science.gov (United States)

    Alba, Sandra; Bakker, Mirjam I; Hatta, Mochammad; Scheelbeek, Pauline F D; Dwiyanti, Ressy; Usman, Romi; Sultan, Andi R; Sabir, Muhammad; Tandirogang, Nataniel; Amir, Masyhudi; Yasir, Yadi; Pastoor, Rob; van Beers, Stella; Smits, Henk L

    2016-01-01

    Knowledge of risk factors and their relative importance in different settings is essential to develop effective health education material for the prevention of typhoid. In this study, we examine the effect of household level and individual behavioural risk factors on the risk of typhoid in three Indonesian islands (Sulawesi, Kalimantan and Papua) in the Eastern Indonesian archipelago encompassing rural, peri-urban and urban areas. We enrolled 933 patients above 10 years of age in a health facility-based case-control study between June 2010 and June 2011. Individuals suspected of typhoid were tested using the typhoid IgM lateral flow assay for the serodiagnosis of typhoid fever followed by blood culture testing. Cases and controls were defined post-recruitment: cases were individuals with a culture or serology positive result (n = 449); controls were individuals negative to both serology and culture, with or without a diagnosis other than typhoid (n = 484). Logistic regression was used to examine the effect of household level and individual level behavioural risk factors and we calculated the population attributable fraction (PAF) of removing each risk significant independent behavioural risk factor. Washing hands at critical moments of the day and washing hands with soap were strong independent protective factors for typhoid (OR = 0.38 95% CI 0.25 to 0.58 for each unit increase in hand washing frequency score with values between 0 = Never and 3 = Always; OR = 3.16 95% CI = 2.09 to 4.79 comparing washing hands with soap sometimes/never vs. often). These effects were independent of levels of access to water and sanitation. Up to two thirds of cases could be prevented by compliance to these practices (hand washing PAF = 66.8 95% CI 61.4 to 71.5; use of soap PAF = 61.9 95%CI 56.7 to 66.5). Eating food out in food stalls or restaurant was an important risk factor (OR = 6.9 95%CI 4.41 to 10.8 for every unit increase in frequency score). Major gains could potentially be

  18. Is the Hawaiian Archipelago dominantly Loa-trend?

    Science.gov (United States)

    Weis, D.; Harrison, L.; Garcia, M. O.; Rhodes, M. M.

    2015-12-01

    Hawaiian volcanoes are distributed en echelon on the islands along two chains, the Loa and Kea trends, that are geographically and geochemically distinct1,2. These geochemical differences may be attributed to source zoning (concentric or bilateral) of the Hawaiian mantle plume (HMP) or to variations in pressure and temperature of melting. Most of these models assume a degree of independence of the two trends that is perhaps not realistic. To explore the isotopic characteristics of two "Kea"-trend volcanoes with transitional signatures, we analyzed 11 samples of Kohala shield-stage tholeiitic lavas and three from Haleakala for high-precision Pb-Nd-Sr-Hf isotopes. These samples are transitional in all isotopic systems between Loa and Kea compositions and cross-over the Pb-Pb boundary3. Minor cross-overs had been documented in Mauna Kea4, Kilauea5, and W Molokai6 basalts. A bilateral or concentric view of the HMP is thus too simplistic. Statistical analysis of the MC-ICP-MS or triple-spike shield tholeiite data (n>600) and the existence of three Pb-Pb trends originating from average Loa indicate that Loa is the dominant mantle source composition on the archipelago. Isotopically, four geochemical groups are identified: Kea (Mauna Kea, Kilauea), average Loa (Mauna Loa, Hualalai, Kauai, Waianae, W. Molokai, Loihi), enriched Loa (Koolau Makapuu, Lanai, Kahoolawe) and transitional Kea (E. Molokai, W. Maui, Haleakala, Kohala). The implications are: 1) HMP source components refresh and grade into and out of existence on a smaller timescale than previously thought; 2) the Kea trend is also heterogeneous; and 3) vertical heterogeneity of the plume is important on a regional scale as well as at the scale of individual volcanoes6. 1Jackson et al., 1972, GSA Bull. 83, 1-17. 2Weis et al., 2011, Nat. Geosci., 4, 831-838. 3Abouchami et al., 2005, Nature, 434, 851-856. 4Eisele et al., 2003, G-cubed, 4, 5, 32 pages. 5Marske et al., 2007, EPSL, 259, 34-50. 6Xu et al., 2014, GCA, 132

  19. Colonization and diversification of aquatic insects on three Macaronesian archipelagos using 59 nuclear loci derived from a draft genome.

    Science.gov (United States)

    Rutschmann, Sereina; Detering, Harald; Simon, Sabrina; Funk, David H; Gattolliat, Jean-Luc; Hughes, Samantha J; Raposeiro, Pedro M; DeSalle, Rob; Sartori, Michel; Monaghan, Michael T

    2017-02-01

    The study of processes driving diversification requires a fully sampled and well resolved phylogeny, although a lack of phylogenetic markers remains a limitation for many non-model groups. Multilocus approaches to the study of recent diversification provide a powerful means to study the evolutionary process, but their application remains restricted because multiple unlinked loci with suitable variation for phylogenetic or coalescent analysis are not available for most non-model taxa. Here we identify novel, putative single-copy nuclear DNA (nDNA) phylogenetic markers to study the colonization and diversification of an aquatic insect species complex, Cloeon dipterum L. 1761 (Ephemeroptera: Baetidae), in Macaronesia. Whole-genome sequencing data from one member of the species complex were used to identify 59 nDNA loci (32,213 base pairs), followed by Sanger sequencing of 29 individuals sampled from 13 islands of three Macaronesian archipelagos. Multispecies coalescent analyses established six putative species. Three island species formed a monophyletic clade, with one species occurring on the Azores, Europe and North America. Ancestral state reconstruction indicated at least two colonization events from the mainland (to the Canaries, respectively Azores) and one within the archipelago (between Madeira and the Canaries). Random subsets of the 59 loci showed a positive linear relationship between number of loci and node support. In contrast, node support in the multispecies coalescent tree was negatively correlated with mean number of phylogenetically informative sites per locus, suggesting a complex relationship between tree resolution and marker variability. Our approach highlights the value of combining genomics, coalescent-based phylogeography, species delimitation, and phylogenetic reconstruction to resolve recent diversification events in an archipelago species complex. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Quantifying and interpreting nestedness in habitat islands

    DEFF Research Database (Denmark)

    Matthews, Thomas J.; Cottee-Jones, H. Eden W.; Whittaker, Robert James

    2015-01-01

    Aim: The concept of nestedness is important in determining the relative contribution to overall system diversity of different habitat patches within a fragmented system. Much of the previous work on nestedness has focused on islands within oceans (islands sensu stricto). The largest analysis...... with fragment area, suggesting that structured extinctions may be important in determining the composition of certain habitat island communities. We found that the degree of nestedness in an archipelago is an important consideration for systematic conservation planning. Main conclusions: Significant nestedness...... is considerably less common in habitat islands than previously reported. Strategic guidance for conservation planning should proceed on a case by case basis, and previous conservation recommendations based on the assumption of significant nestedness in most fragmented landscapes may need to be re-evaluated....

  1. Gozitan crossings : the impact of migration and return migration on an island community [book review

    OpenAIRE

    Xerri, Raymond C.

    2017-01-01

    Living on an island offers both advantages and disadvantages. Many people on the Inner Hebrides off the north-western coast of Scotland have to travel to the mainland either on a daily or on a weekly basis in order to go to work. The same can be said to islands such as the Isle of Man or the Orkney Islands. The same might also be said for the inhabitants of the Aeolian Islands, off the western coast of nearby Sicily. Gozo is no exception.

  2. A new species of insular Rock Gecko (Genus Cnemaspis Strauch, 1887) from the Bidong Archipelago, Terengganu, Peninsular Malaysia.

    Science.gov (United States)

    Grismer, L Lee; Wood, Perry L; Ahmad, Amirrudin B; Sumarli, Alexandra S-I; Vazquez, Jessika J; Ismail, Lukman H B; Nance, Ronald; Mohd-Amin, Muhammad Afif B; Othman, Mohamad N A B; Rizaijessika, Syed A; Kuss, Maria; Murdoch, Matthew; Cobos, Anthony

    2014-01-24

    A new insular species Cnemaspis bidongensis sp. nov. (Squamata: Gekkonidae), is described from Pulau Bidong, Terengganu, Peninsular Malaysia and bears a unique suite of morphological and color pattern characters that differentiate it from all other congeners. Cnemaspis bidongensis sp. nov. is the sister species to C. kendallii (Gray) and represents the fifth insular endemic species of Cnemaspis on archipelagos along the east coast of Peninsular Malaysia. This species survived massive deforestation of the small island of Bidong (260 ha) from the mid 1970s to the early 1990s when the island served as a Vietnamese refugee camp and harbored as many as 40,000 people at one time. We hypothesize that this species' generalized lifestyle contributed to its survival, allowing it to seek refuge in rocky microhabitats.

  3. Community structures of soil animals and survival of land snails on an island of the Ogasawara Archipelago Estruturas de comunidades de animais de solo e sobrevivência dos caracóis terrestres numa ilha do Arquipélago Ogasawara

    OpenAIRE

    Motohiro Hasegawa; Shinji Sugiura; Masamichi T. Ito; Aska Yamaki; Keiko Hamaguchi; Toshio Kishimoto; Isamu Okochi

    2009-01-01

    On Chichijima, one of the Ogasawara (Bonin) Islands located in the Western Pacific Ocean, land snails have declined, the suggested cause being predation pressure by an invasive flatworm (Platydemus manokwari). Soil fauna were investigated in areas where the snail survives, and where it has become extinct. Much of the fauna, dominated by introduced earthworms and ants, was undiminished, however, one undescribed but endemic carabid (Badister sp.), which selectively feeds on land snails, was abs...

  4. Species composition, diversity and stratification in subtropical evergreen broadleaf forests along a latitudinal thermal gradient in the Ryukyu Archipelago, Japan

    Directory of Open Access Journals (Sweden)

    S.M. Feroz

    2015-07-01

    Full Text Available A well-developed evergreen broadleaf forest exists in the northern part of Okinawa and in the central part of the Ishigaki Islands in the Ryukyu Archipelago, Japan. All woody plants were identified to species level and their heights and diameters were measured in a 750m2 plot in Okinawa and a 400m2 plot in the Ishigaki Islands. Species overlap, dominance, diversity, multi-strata structure, and spatial distribution were calculated. The floristic composition in Okinawa was found to be different from that in Ishigaki. The species overlap between strata was higher in Okinawa than in Ishigaki. Species diversity and evenness tended to increase from the top down in Okinawa and the reverse in Ishigaki. Mean tree weight of each stratum decreased and tree density increased from top down in both forests. This trend resembled the mean weight–density trajectory of self-thinning plant populations. The degree of stand stratification, species richness and species diversity for trees with DBH ⩾4.5  cm increased along the latitudinal thermal gradient in the Ryukyu Archipelago. Thus, trees in the lower strata of Okinawa and upper strata of Ishigaki are important for sustainable maintenance of higher woody species diversity in the Ryukyu Archipelago.

  5. Islands, Island Studies, Island Studies Journal

    Directory of Open Access Journals (Sweden)

    Godfrey Baldacchino

    2006-05-01

    Full Text Available Islands are sites of innovative conceptualizations, whether of nature or human enterprise, whether virtual or real. The study of islands on their own terms today enjoys a growing and wide-ranging recognition. This paper celebrates the launch of Island Studies Journal in the context of a long and thrilling tradition of island studies scholarship.

  6. Spatial variability in the structure of intertidal crab and gastropod assemblages within the Seychelles Archipelago (Indian Ocean)

    Science.gov (United States)

    Smale, Dan A.; Barnes, David K. A.; Barnes, Richard S. K.; Smith, David J.; Suggett, David J.

    2012-04-01

    Tropical nearshore ecosystems represent global hotspots of marine biodiversity and endemism but are often poorly understood and impacted by human activities. The Seychelles Archipelago (Western Indian Ocean) sustains a wealth of marine life, much of which is threatened by rapid development associated with tourism and climate change. Six marine parks exist within the Archipelago, but their biodiversity value and ecological health are poorly known, especially with regards to non-fish and coral species. Here we investigate spatial patterns of littoral biodiversity on 6 islands, 5 of which were granitic and within marine parks, including the first surveys of Curieuse and Ile Cocos. Our surveys formed a nested sampling design, to facilitate an examination of variability in species richness, faunal abundance, taxonomic distinctness and assemblage composition at multiple spatial scales, from islands (> 100 s km) to quadrats (metres). We identified (mostly to species) and enumerated two target taxa, brachyuran decapod crustaceans and gastropod molluscs, and recorded over 8300 individuals belonging to over 150 species. Crabs and gastropods exhibited different patterns of spatial variability, as crab assemblages were generally more distinct between islands, while gastropod assemblages were markedly variable at the smallest spatial scales of 'patch' and 'quadrat'. Intertidal biodiversity was greatest on Curieuse Island and least at Desroches, the latter was being the only coral atoll we surveyed and thereby differing in its geological and ecological context. We discuss likely drivers of these biodiversity patterns and highlight urgently-needed research directions. Our assessment of the status of poorly-known invertebrate assemblages across the Seychelles will complement more extensive surveys of coral and fish assemblages and, in doing so, provide a useful baseline for monitoring the effects of key stressors in the region, such as coastal development and climate change.

  7. Paleogene geology and chronology of southwestern Umnak Island, Aleutian Islands, Alaska ( USA).

    Science.gov (United States)

    McLean, H.; Hein, J.R.

    1984-01-01

    A slightly deformed marine sedimentary sequence reflecting volcanic arc sedimentation from late Eocene to early Oligocene is intruded by hypabyssal quartz diorite sills and small plutons with apparent ages of about 30 Ma, ie, middle Oligocene. Chemical data from igneous rocks exhibit calc-alkaline and tholeiitic volcanic arc differentiation trends. The fossil ages and radiometric dates from SW Umnak Island are similar to those reported from other central and E Aleutian islands, and indicate uniformity in the chronology and tectonic development of the archipelago during the Paleogene. Paleomagnetic data suggest possible northward movement but remain equivocal and more work is indicated. -after Authors

  8. Dune-like dynamic of Martian Aeolian large ripples

    Science.gov (United States)

    Silvestro, S.; Vaz, D. A.; Yizhaq, H.; Esposito, F.

    2016-08-01

    Martian dunes are sculpted by meter-scale bed forms, which have been interpreted as wind ripples based on orbital data. Because aeolian ripples tend to orient and migrate transversely to the last sand-moving wind, they have been widely used as wind vanes on Earth and Mars. In this report we show that Martian large ripples are dynamically different from Earth's ripples. By remotely monitoring their evolution within the Mars Science Laboratory landing site, we show that these bed forms evolve longitudinally with minimal lateral migration in a time-span of ~ six terrestrial years. Our observations suggest that the large Martian ripples can record more than one wind direction and that in certain cases they are more similar to linear dunes from a dynamic point of view. Consequently, the assumption of the transverse nature of the large Martian ripples must be used with caution when using these features to derive wind directions.

  9. Armoring and vertical sorting in aeolian dune fields

    Science.gov (United States)

    Gao, Xin; Narteau, Clément; Rozier, Olivier

    2016-04-01

    Unlike ripples, there are only few numerical studies on grain-size segregation at the scale of dunes in aeolian environments. Here we use a cellular automaton model to analyze vertical sorting in granular mixtures under steady unidirectional flow conditions. We investigate the feedbacks between dune growth and the segregation mechanisms by varying the size of coarse grains and their proportion within the bed. We systematically observe the development of a horizontal layer of coarse grains at the top of which sorted bed forms may grow by amalgamation. The formation of such an armor layer controls the overall sediment transport and availability. The emergence of dunes and the transition from barchan to transverse dune fields depend only on the grain size distribution of the initial sediment layer. As confirmed by observation, this result indicates that armor layers should be present in most arid deserts, where they are likely to control dune morphodynamics.

  10. The nature and formation of aeolian mineral dust material

    Science.gov (United States)

    Smalley, Ian; O'hara-Dhand, Ken; McLaren, Sue

    2013-04-01

    Aeolian dust affects climate and records past climates. It has become a much studied material but there has been a certain lack of emphasis on the actual nature of the dust, and an even greater neglect of actual production mechanisms for dust particles. Huge amounts of dust may be raised from the Bodele depression and other parts of North Africa, and much of it may be carried across the North Atlantic to aid in soil formation in Brazil. But what does it consist of? We know that much of the Bodele dust is diatoms from old Lake Chad, but what of the lithological inorganic mineral content? A very crude division of aeolian dust into large dust(say around 20-50um) and small dust (2-5um)has been proposed. Much of the study of loess has been confused by the failure to make this distinction, and similar problems may arise in the study of the finer fractions of aeolian dust. Much aeolian material is clay-mineral based- formed from clay mineral aggregates(CMA), from lake bottom sediments. This can form large dust particles, as in parna in Australia, but also contributes largely to small long travel aerosolic dust. Another major contributor is the quartz fragment. The large dust for classic loess deposits is mostly quartz silt- and there is considerable discussion about the controls that affect quartz silt. There are some interesting modalities in the world of quartz particle sedimentology which need to be examined. Quartz sand (say 200-500um) is the key initiating material and the formation processes for quartz sand have a down-the-line effect on the formation of smaller particles. The central observation is the action of two processes- a eutectic-like reaction in the proto-rock granite which defines the essential nature of sand particles, and the high-low displacive crystallographic transformation which introduces tensile stresses into the quartz particle systems. The limited range of eutectic particle size means a limited range of tensile stresses. A neat combination of

  11. The National Aeolian Detritus Project, A Student-controlled, Standards-based Research Opportunity for Middle and Hight School Students

    Science.gov (United States)

    Sammons, J. I.; Murray, D. D.; Reid, J. B.

    2001-12-01

    Schools across the United States are adopting Standards-based philosophies and practices at a quickening pace. Two of the biggest challenges in this transition are the integration of concepts and the development of meaningful evaluation of student progress. The National Aeolian Detritus Project is a collaboration among Jamestown School, the University of Rhode Island, Hampshire College, the Rhode Island Space Grant Consortium at Brown University and the Rhode Island Nuclear Science Center. This Project provides students with an opportunity to integrate and enhance previous elements of instruction and allows them decision-making control over the direction of an extended research investigation. This project also provides opportunities for undergraduate community service development through University - Local School collaboration and mentoring. Students first collect Aeolian Detritus, that is, randomly deposited airborne particulate matter (APM) by deploying flat sheet collectors. Retained APM is removed from the collectors with repulpable tape and concentrated by vacuum filtration. APM is initially identified by simple light microscopy, solubility, density, and magnetic response. More advanced identification includes ICP and Neutron Activation. With assistance from collaborating universities, students craft research questions based on these initial samples and develop investigation designs. Sample research questions include: 1) Can insect infestations or possible defoliation events be predicted by identification of insect bodies, parts, and excrement? 2) What information can we collect about micrometeorites when typed, analyzed, and compared to NASA comet track data? 3) Can the distribution of flora be confirmed or modified based on pollen grain collection and mapping? 4) Can the distribution of mineral particulate matter be mapped by collection and comparison with wind patterns over known geologic features? Schools correlate collection data with National Weather

  12. Downslope coarsening in aeolian grainflows of the Navajo Sandstone

    Science.gov (United States)

    Loope, David B.; Elder, James F.; Sweeney, Mark R.

    2012-07-01

    Downslope coarsening in grainflows has been observed on present-day dunes and generated in labs, but few previous studies have examined vertical sorting in ancient aeolian grainflows. We studied the grainflow strata of the Jurassic Navajo Sandstone in the southern Utah portion of its outcrop belt from Zion National Park (west) to Coyote Buttes and The Dive (east). At each study site, thick sets of grainflow-dominated cross-strata that were deposited by large transverse dunes comprise the bulk of the Navajo Sandstone. We studied three stratigraphic columns, one per site, composed almost exclusively of aeolian cross-strata. For each column, samples were obtained from one grainflow stratum in each consecutive set of the column, for a total of 139 samples from thirty-two sets of cross-strata. To investigate grading perpendicular to bedding within individual grainflows, we collected fourteen samples from four superimposed grainflow strata at The Dive. Samples were analyzed with a Malvern Mastersizer 2000 laser diffraction particle analyser. The median grain size of grainflow samples ranges from fine sand (164 μm) to coarse sand (617 μm). Using Folk and Ward criteria, samples are well-sorted to moderately-well-sorted. All but one of the twenty-eight sets showed at least slight downslope coarsening, but in general, downslope coarsening was not as well-developed or as consistent as that reported in laboratory subaqueous grainflows. Because coarse sand should be quickly sequestered within preserved cross-strata when bedforms climb, grain-size studies may help to test hypotheses for the stacking of sets of cross-strata.

  13. Volcano-tectonic framework of a linear volcanic ridge (Faial-Pico ridge, Azores Archipelago) assessed by paleomagnetic studies

    Science.gov (United States)

    Silva, Pedro; Henry, Bernard; Lopes, Ana; Marques, Fernando; Madureira, Pedro; Hildenbrand, Anthony; Madeira, José; Nunes, João; Roxerová, Zuzana

    2016-04-01

    The morphology of volcanic oceanic islands results from the alternation between constructive and destructive episodes. In this study directional analyses obtained from paleomagnetic studies are used as a tool to achieve relative rotations related with destructive processes intra the Pico-Faial linear volcanic ridge (Azores archipelago; North Atlantic). A total of 45 lava flows and one dyke were sampled preferable along lava piles though to record volcano-tectonic movements. The respective paleomagnetic results are able to show important rotations within the two islands that resemble the onshore signature of this ridge. Paleomagnetic directions retrieved here mostly show elliptical distribution of ChRM's sub-perpendicular to volcanic ridge. Such distribution agrees with the development of listric faults plunging towards the axis of the volcanic ridge at Faial Island and towards offshore at the Topo complex of Pico Island. In Faial Island, the "collapse" related to the magma chamber decompression was accommodated by brittle deformation with listric faults plunging toward the core of the formed graben. On Pico Island, this collapse was probably of less importance and simply accommodated by a local tilting. Listric faults then should have been developed, in the opposite direction (compared to Faial Island case) relatively to the collapsed area, to compensate a relative local uplift. Accordingly paleomagnetic studies appear as key data to retrieve intra-islands deformations due to the volcano-tectonic balance responsible for the construction and destruction of such unstable buildings. This important tool to address georisks and natural hazards remains poorly explored and need to be strongly developed. The author wish to acknowledge MEGAHAZARDS (PTDC/CTE-GIX/108149/2008) and REGENA (PTDC/GEO-FIQ/3648/2012) projects for its major contribution without which this work wouldn't be possible. Publication supported by project FCT UID/GEO/50019/2013 - Instituto Dom Luiz.

  14. Diagenetic history of lower Pliocene rhodoliths of the Azores Archipelago (NE Atlantic): Application of cathodoluminescence techniques.

    Science.gov (United States)

    Rebelo, A C; Meireles, R P; Barbin, V; Neto, A I; Melo, C; Ávila, S P

    2016-01-01

    The diagenetic history of calcareous fossils is required for their application as palaeoenvironmental indicators. In this study, cathodoluminescence-microscopy (CL microscopy) and back scatter electron image-energy dispersive X-ray spectroscopy (BSE-EDS microscopy) were applied to Pliocene rhodoliths from the Azores Archipelago (NE Atlantic) in order to gain additional insight regarding the trace element content distribution throughout the algae thalli, and to ascertain palaeoenvironmental interpretations. Two types of luminescence were obtained: (1) high and (2) low luminescence. Rhodoliths with high luminescence are related with high concentrations of Mn(2+) in seawater and low luminescence rhodoliths are related with low concentrations of Mn(2+) in seawater. When the rhodoliths were deposited at about 4.0-4.5 Ma, the shoreline configuration of Santa Maria Island was much different than today. The influence of volcanic activity due to the extrusion of lavas and associated products and/or the presence of active shallow-water hydrothermal vents, was reflected in the sea water chemistry, with penecontemporaneous palaeoshores of the island featuring a high sea water concentration of Mn(2+), which mirrored on the rhodolith Mn(2+) high concentration. By contrast, rhodoliths located about 2.8 and 2.9 km from the shore, in areas with low seawater Mn(2+) concentration, had low luminescence, reflecting the low Mn(2+) concentration in seawater. Rhodoliths chemical data and the geological history of the island proved to be congruent with the palaeogeographical reconstruction of Santa Maria Island at the time of the formation of the rhodoliths.

  15. Island Archaeology: In Search of a New Horizon

    Directory of Open Access Journals (Sweden)

    Arie Boomert

    2007-05-01

    Full Text Available This paper charts the academic development of “island archaeology” from its roots in Darwinist and anthropological island studies through island biogeography to processual and post-processual archaeology. It is argued that the rarely made explicit yet fundamental premise of island archaeology that insular human societies show intrinsic characteristics essentially dissimilar from those on mainlands is false. The persistence of this misconception is due in part to the emphasis on islands as ideal units of analysis. It is suggested that island societies should be studied at the level of the archipelago and/or mainland coastal setting within their maritime cultural framework, ultimately leading up to an archaeology of maritime identity.

  16. Formation mechanism and development pattern of aeolian sand landform in Yarlung Zangbo River valley

    Institute of Scientific and Technical Information of China (English)

    李森; 董光荣; 申建友; 杨萍; 刘贤万; 王跃; 靳鹤龄; 王强

    1999-01-01

    Aeolian sand landforms in the Yarlung Zangbo River valley can be divided into 4 classes and 21 types. The river valley has favourable environment conditions for the development of aeolian sand landforms. Simulation of MM4 mid-scale climate model showed that the near-surface flow field and wind vector field during the winter half year in the fiver valley are generally favourable for the aeolian sand deposition and as a whole they also affect the distribution zones and sites of aeolian sand landforms. Sand dunes and sand dune groups in the fiver valley developed mainly in three ways, namely windward retarding deposition, leeward back flow deposition and bend circumfluence deposition. Through alternating positive-reverse processes of sand dune formation under wind actions and sand dune vanishing under water actions, sand dunes developed from primary zone through main-body zone then to vanishing zone where climbing dunes and falling dunes are declining and are even disappearing.

  17. Eco-Casting of Aeolian Blades and Solar Panels With Composites ...

    African Journals Online (AJOL)

    Eco-Casting of Aeolian Blades and Solar Panels With Composites Materials Via RTM Technology. ... Journal of Fundamental and Applied Sciences ... ecodesign; RTM process; permeability; sustainable development; renewable energy ...

  18. Sponge interactions with spatial competitors in the Spermonde Archipelago

    NARCIS (Netherlands)

    Voogd, de N.J.; Becking, L.E.; Hoeksema, B.W.; Noor, A.; Soest, van R.W.M.

    2003-01-01

    This study describes the in situ effects of four bioactive sponges on their neighbours at three different locations and two depths in the Spermonde Archipelago, SW Sulawesi, Indonesia. The natural rates of interaction between the sponge species and eight possible competitive invertebrate groups were

  19. Sponge beta diversity in the Spermonde Archipelago, SW Sulawesi, Indonesia

    NARCIS (Netherlands)

    Voogd, de N.J.; Cleary, D.F.R.; Hoeksema, B.W.; Noor, A.; Soest, van R.W.M.

    2006-01-01

    Sponge assemblages were investigated in the Spermonde Archipelago, southwestern Sulawesi, Indonesia. In this study spatial patterns of sponge similarity among sites were significantly related to remotely sensed environmental variables, the degree of human settlement and depth, but not to the distanc

  20. Irreversible mass loss of Canadian Arctic Archipelago glaciers

    NARCIS (Netherlands)

    Lenaerts, J.T.M.; van Angelen, J.H.; van den Broeke, M.R.; Gardner, A.S.; Wouters, Bert; van Meijgaard, E.

    2013-01-01

    The Canadian Arctic Archipelago (CAA) contains the largest volume of glacier ice on Earth outside of Antarctica and Greenland. In the absence of significant calving, CAA glacier mass balance is governed by the difference between surface snow accumulation and meltwater runoff—surface mass balance. He

  1. Seaweeds of the Spermonde Archipelago, SW Sulawesi, Indonesia

    NARCIS (Netherlands)

    Verheij, E.; Prud’homme van Reine, W.F.

    1993-01-01

    Seaweeds are important components of tropical reef systems. The present paper deals with the Chlorophyta, Phaeophyta and noncoralline Rhodophyta collected by the first author in the Spermonde Archipelago, SW Sulawesi, Indonesia, during the Buginesia-III project (November 1988-November 1990). Additio

  2. Sponge interactions with spatial competitors in the Spermonde Archipelago

    NARCIS (Netherlands)

    Voogd, de N.J.; Becking, L.E.; Hoeksema, B.W.; Noor, A.; Soest, van R.W.M.

    2003-01-01

    This study describes the in situ effects of four bioactive sponges on their neighbours at three different locations and two depths in the Spermonde Archipelago, SW Sulawesi, Indonesia. The natural rates of interaction between the sponge species and eight possible competitive invertebrate groups were

  3. Hydrological indications of aeolian salts in mid-latitude deserts of northwestern China

    Indian Academy of Sciences (India)

    Bing-Qi Zhu

    2016-06-01

    Large sandy deserts in middle latitude of northwestern China were studied on salt variations in modernand ancient aeolian sediments, aiming to explore their hydrological indications at the present and past.Globally, sulphate is rich in arid to semi-arid deserts, including the aeolian loess sediments in China andsoils in low-latitude deserts, but is less common in the aeolian sediments from the mid-latitude desertsin this study. The compositional differences between aeolian salts and local natural waters is evident,indicating the chemistry of aeolian salts and the associated parent brines may be significantly differentthan that predicted for hydrologically closed systems. The formation of aeolian salts in the studieddeserts is strongly controlled by earth surface processes in a large scale but not in a local scale. Verticalchanges in facies and salinities are abrupt in the studied palaeo-aeolian sediment samples, which wereinterbedded by lacustrine/fluvial sediments with OSL and ^{14}C ages ranging between 40 and 2 ka BP,reflecting rapid high-amplitude changes in hydrological settings during late Pleistocene to later Holocenein these ancient playa systems. A great difference in salt composition between aeolian and lacustrinesediments suggests that the inorganic salt is a latent geoproxy in revealing local hydrological variationsand climate change in the desert areas. But the environmental indications could be amphibolous for thesedimentary sequences with dual/multiple depositional end-members; under this situation an increase insequence salinity does not always represent an enhanced environmental aridity. Ancient playas are aridor humid at the same time based on several sporadic records is not a valid approach to correlation of saltdeposits in adjacent saline playa basin in the studied areas. Effects of earth surface processes includingerosion, deposition and other processes on sediment properties will bias the hydrological implications ofsediment salinity.

  4. Hydrological indications of aeolian salts in mid-latitude deserts of northwestern China

    Science.gov (United States)

    Zhu, Bing-Qi

    2016-06-01

    Large sandy deserts in middle latitude of northwestern China were studied on salt variations in modern and ancient aeolian sediments, aiming to explore their hydrological indications at the present and past. Globally, sulphate is rich in arid to semi-arid deserts, including the aeolian loess sediments in China and soils in low-latitude deserts, but is less common in the aeolian sediments from the mid-latitude deserts in this study. The compositional differences between aeolian salts and local natural waters is evident, indicating the chemistry of aeolian salts and the associated parent brines may be significantly different than that predicted for hydrologically closed systems. The formation of aeolian salts in the studied deserts is strongly controlled by earth surface processes in a large scale but not in a local scale. Vertical changes in facies and salinities are abrupt in the studied palaeo-aeolian sediment samples, which were interbedded by lacustrine/fluvial sediments with OSL and 14C ages ranging between 40 and 2 ka BP, reflecting rapid high-amplitude changes in hydrological settings during late Pleistocene to later Holocene in these ancient playa systems. A great difference in salt composition between aeolian and lacustrine sediments suggests that the inorganic salt is a latent geoproxy in revealing local hydrological variations and climate change in the desert areas. But the environmental indications could be amphibolous for the sedimentary sequences with dual/multiple depositional end-members; under this situation an increase in sequence salinity does not always represent an enhanced environmental aridity. Ancient playas are arid or humid at the same time based on several sporadic records is not a valid approach to correlation of salt deposits in adjacent saline playa basin in the studied areas. Effects of earth surface processes including erosion, deposition and other processes on sediment properties will bias the hydrological implications of sediment

  5. Geochemistry of the alkaline volcanicsubvolcanic rocks of the Fernando de Noronha Archipelago, southern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Rosana Peporine Lopes

    Full Text Available The Fernando de Noronha Archipelago presents, on its main island, a centrally-located stratigraphic unit, the Remédios Formation (age around 8 - 12 Ma constituted by basal pyroclastic rocks intruded by dikes, plugs and domes of varied igneous rocks, capped by flows and pyroclastics of mafic to ultramafic rocks of the Quixaba Formation (age around 1 - 3 Ma, which is limited from the underlying unit by an extensive irregular erosion surface. A predominant sodic Remédios series (basanites, tephrites, tephriphonolites, essexite, phonolites can be separated from a moderately potassic Remédios sequence (alkali basalts, trachyandesites, trachytes, both alkaline series showing mostly continuous geochemical trends in variation diagrams for major as well as trace elements, indicating evolution by crystal fractionation (mainly, separation of mafic minerals, including apatites and titanites. There are textural and mineralogical evidences pointing to hybrid origin of some intermediate rocks (e.g., resorbed pyroxene phenocrysts in basaltic trachyandesites, and in some lamprophyres. The primitive Quixaba rocks are mostly melanephelinites and basanites, primitive undersaturated sodic types. Geology (erosion surface, stratigraphy (two distinct units separated by a large time interval, petrography (varied Remédios Formation, more uniform Quixaba unit and geochemistry indicate that the islands represent the activity of a protracted volcanic episode, fueled by intermittent melting of an enriched mantle, not related to asthenospheric plume activity.

  6. Sustainable development? Salmon aquaculture and late modernity in the archipelago of Chiloé, Chile

    Directory of Open Access Journals (Sweden)

    Jonathan R. Barton

    2016-11-01

    Full Text Available Chiloé is an archipelago that has, since the 1980s, become one of the motors of the Chilean economy. Salmon aquaculture swiftly transformed the tradition of isolation and poverty that had defined the local identity and livelihoods. This is now changing due to the rapid experience of modernity. This modernity is driven by transnational capital and large-scale state intervention in the promotion of salmon aquaculture and its current central role in defining development in the islands. While this sector has generated private and public employment and infrastructure, there has also been an important shift in the expectations and aspirations of the local population, towards increased hybridization and also a mercantilization of island culture. The success of salmon production reveals that the conditions of isolation can be transformed, and even benefits reaped from integration into the modern world –globalised, capitalist and rational, rather than traditional– however it also entails risks for the sustainability of fragile socio-ecological systems, including the existence of traditional and alternative livelihoods.

  7. 海岛户外心理拓展训练可行性分析及模式建构——以舟山群岛为例%Feasibility Analysis on Island Outdoor Psychological Training and Model Construction --A Case Study of Zhoushan Archipelago

    Institute of Scientific and Technical Information of China (English)

    丁芳盛

    2012-01-01

    文章通过对海岛户外心理拓展训练的内涵和特征的分析,从环境资源、时机因素、经验因素和效益建设四个维度阐述其可行性,并就训练理念、训练目标、训练流程进行深入探讨,尝试形成海岛户外心理拓展训练的一般模式,以期实现海岛户外心理拓展训练科学规范的管理。%The article analyzes the content and characteristics on island outdoor psychological training. It investigates the training project feasibility from four dimensions: environmental resources, time, experience and efficiency. It also has an in-depth exploration on training philosophy, training objectives and training process, trying to form the general pattern on the island outdoor psychological training and to implement scientific and standardized management.

  8. Facies, Stratigraphic and Depositional Model of the Sediments in the Abrolhos Archipelago (Bahia, BRAZIL)

    Science.gov (United States)

    Matte, R. R.; Zambonato, E. E.

    2012-04-01

    Located in the Mucuri Basin on the continental shelf of southern Bahia state, northeast Brazil, about 70 km from the city of Caravelas,the Abrolhos archipelago is made up of five islands; Santa Barbara, Redonda, Siriba, Guarita and Sueste. The exhumed sediments in the Abrolhos archipelago are a rare record of the turbidite systems which fill the Brazilian Atlantic Basin, and are probably an unprecedented example of a plataform turbidite system (Dr. Mutti, personal communication). Despite the limited area, the outcrops display a wide facies variation produced by different depositional processes, and also allow for the observation of the layer geometries. Associated with such sedimentary rocks, the Abrolhos Volcanic Complex belongs stratigraphically to the Abrolhos Formation. These igneous rocks were dated by the Ar / Ar method, with ages ranging from 60 to 40 My, placing such Volcanic Complex between the Paleocene and Eocene. The sedimentary section is best exposed in the Santa Barbara and Redonda islands and altogether it is 70 m thick. The measured vertical sections show a good stratigraphic correlation between the rocks of the western portion of the first island and those of Redonda Island. However, there is no correlation between the eastern and western portions of Santa Barbara Island, since they are very likely interrupted by the igneous intrusion and possibly by faulting. The sedimentary stack consists of deposits with alternated regressive and transgressive episodes interpreted as high frequency sequences. The coarse facies, sandstones and conglomerates, with abrupt or erosive bases record regressive phases. On the other hand, finer sandstones and siltstones facies, which are partly bioturbated, correspond to phases of a little sediment supply. In the central and eastern portions of Santa Barbara Island, there is a trend of progradational stacking, while both in the western portion of Santa Barbara and in Redonda islands an agradational trend is observed

  9. IMPACT OF FISHING AND HABITAT DEGRADATION ON THE DENSITY OF BANGGAI CARDINAL FISH (Pterapogon kauderni, Koumans 1933 IN BANGGAI ARCHIPELAGO, INDONESIA

    Directory of Open Access Journals (Sweden)

    Kamaluddin Kasim

    2014-06-01

    Full Text Available Banggai cardinal fish (Pterapogonkauderni, Koumans 1933 is uncommon example of a marine fish with distributed in small range area while being in highly exploited. This fish is in high demand as an ornamental fish. However, the information on the number of density is limited. An underwater visual fish census survey was conducted in June to July 2010 at 18 fishing sites around Banggai archipelago to estimate the density of the stock and assess the impact of fishing and habitat on density. The areas are divided into three main islands, namely Banggai Island, Peleng Island, Toropot-Tumbak-Labobo Island. The lowest density index of the P. kauderni recorded at Kindandal village on Peleng Island, 0.014 fish/m2while the highest abundance index of 3.0 fish/m2 found at Toropot village at Toropot Island. In three survey sites (Bonebaru and Toropot villages where the fishing activities are still ongoing, the density has declined compared to the survey conducted in 2004. Majority of the villages in Peleng Island have lower density compared with the other islands probably due to the degradation of microhabitat of P. kauderni. In many cases, microhabitat degradation might be as a result of collection of sea urchins and sea anemone for consumption by local community.

  10. A Theory of Island Biogeography for Exotic Species.

    Science.gov (United States)

    Burns, Kevin C

    2015-10-01

    The theory of island biogeography has played a pivotal role in the way ecologists view communities. However, it does not account for exotic species explicitly, which limits its use as a conservation tool. Here, I present the results of a long-term study of plant communities inhabiting an archipelago of small islands off the coast of New Zealand and derive a modified version of the theory of island biogeography to predict differences in the turnover and diversity of native and exotic species. Empirical results showed that, although species richness of both native and exotic plant species increased with island area, native species consistently outnumbered exotic species. Species turnover increased with species richness in both groups. However, opposite to species-area patterns, turnover increased more rapidly with species richness in exotic species. Empirical results were consistent with the modified version of the theory of island biogeography, which distinguishes exotic species from native species by decoupling extinction rates of exotic species from island area, because they are represented by only small populations at the initial stages of invasion. Overall results illustrate how the theory of island biogeography can be modified to reflect the dynamics of exotic species as they invade archipelagos, expanding its use as a conservation tool.

  11. A late Holocene winter monsoon record inferred from the palaeo-aeolian sand dune in the southeastern Mu Us Desert, northern China

    Institute of Scientific and Technical Information of China (English)

    Bing Liu; HeLing Jin; Fan Yang

    2016-01-01

    The variation of the Asian winter monsoonal strength has seriously affected the climate and environmental conditions in the Asian monsoonal region, and even in marginal islands and the ocean in the East Asian region. However, relevant under-standing remains unclear due to the lack of suitable geological materials and effective proxies in the key study areas. Here, we present a grain-size record derived from the palaeo-aeolian sand dune in the southeastern Mu Us Desert, together with other proxies and OSL dating, which reflect a relatively detailed history of the winter monsoon and abrupt environmental events during the past 4.2 ka. Our grain-size standard deviation model indicated that>224μm content can be considered as an indicator of the intensity of Asian winter monsoon, and it shows declined around 4.2–2.1 ka, enhanced but unstable in 2.1–0.9 ka, and obviously stronger since then. In addition, several typical climate events were also documented, forced by the periodic variation of winter monsoonal intensity. These include the cold intervals of 4.2, 2.8, 1.4 ka, and the Little Ice Age (LIA), and relatively warm sub-phases around 3.0, 2.1, 1.8 ka, and the Medieval Warm Period (MWP), which were roughly accordant with the records of the aeolian materials, peat, stalagmites, ice cores, and sea sediments in various lat-itudes of the Northern Hemisphere. Combined with the previous progresses of the Asian summer monsoon, we prelimi-narily confirmed a millennial-scale anti-correlation of Asian winter and summer monsoons in the Late Holocene epoch. This study suggests that the evolution of the palaeo-aeolian sand dune has the potential for comprehending the history of Asian monsoon across the desert regions of the modern Asian monsoonal margin in northern China.

  12. Terrestrial sensitivity to abrupt cooling recorded by aeolian activity in northwest Ohio, USA

    Science.gov (United States)

    Campbell, M.C.; Fisher, T.G.; Goble, R.J.

    2011-01-01

    Optically stimulated luminescence dated sand dunes and Pleistocene beach ridges in northwest Ohio are used to reconstruct landscape modification more than 5000. yr after deglaciation. Four of the OSL ages (13.3-11.1. ka) cluster around the Younger Dryas cold event, five ages (10.8-8.2. ka) cluster around the Preboreal, one young age (0.9-0.7. ka) records more recent aeolian activity, and one age of 15.1-13.1. ka dates a barrier spit in Lake Warren. In northwest Ohio, both landscape instability recorded by aeolian activity and a vegetation response recorded by pollen are coeval with the Younger Dryas. However, the climate conditions during the Preboreal resulting in aeolian activity are not recorded in the available pollen records. From this, we conclude that aeolian dunes and surfaces susceptible to deflation are sensitive to cooler, drier episodes of climate and can complement pollen data. Younger Dryas and Preboreal aged aeolian activity in northwestern Ohio coincides with aeolian records elsewhere in the Great Lakes region east of the prairie-forest ecotone. ?? 2011 University of Washington.

  13. The terrestrial reptile fauna of the Abrolhos Archipelago: species list and ecological aspects

    Directory of Open Access Journals (Sweden)

    ROCHA C. F. D.

    2002-01-01

    Full Text Available We have studied the terrestrial reptile fauna of the Abrolhos Archipelago (a group of five islands located ca. 70 km off the southern coast of the State of Bahia, Brazil and analyze here some of its ecological aspects such as diet, thermal ecology, activity, and some reproductive parameters. Three lizards comprise the archipelago's terrestrial reptile fauna: Tropidurus torquatus (Tropiduridae, Mabuya agilis (Scincidae, and Hemidactylus mabouia (Gekkonidae. The first two are diurnal and the latter is crepuscular/nocturnal (initiating activity at ca. 17:30. The activity period of T. torquatus extended from 5:30 to 18:30 h. Mean field body temperatures of active T. torquatus, M. agilis, and H. mabouia were, respectively, 34.0 ± 3.7ºC (range 23.8-38.0ºC; N = 75, 34.5 ± 2.2ºC (range 30.8-37.0ºC; N = 6, and 26.3 ± 1.1ºC (range 24.8-28.0ºC; N = 8. The predominant prey items in the diet of T. torquatus were ants, coleopterans, and hemipterans. In the diet of M. agilis, coleopterans were the most frequent prey items. For H. mabouia, the most important dietary items were orthopterans. Clutch size of T. torquatus averaged 4.1 ± 1.1 (range 2-6; N = 15 and was significantly related to female size (R² = 0.618; p = 0.001; N = 15. Clutch size for H. mabouia was fixed (two and mean litter size of the viviparous M. agilis was 3.3 ± 0.6 (range 3-4; N = 3. Tropidurus torquatus and H. mabouia deposit their eggs under rocks in the study area, with the former burying them but not the latter; in both species, more than one female often oviposit under the same rock.

  14. An invasive fish and the time-lagged spread of its parasite across the Hawaiian archipelago.

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    Michelle R Gaither

    Full Text Available Efforts to limit the impact of invasive species are frustrated by the cryptogenic status of a large proportion of those species. Half a century ago, the state of Hawai'i introduced the Bluestripe Snapper, Lutjanus kasmira, to O'ahu for fisheries enhancement. Today, this species shares an intestinal nematode parasite, Spirocamallanus istiblenni, with native Hawaiian fishes, raising the possibility that the introduced fish carried a parasite that has since spread to naïve local hosts. Here, we employ a multidisciplinary approach, combining molecular, historical, and ecological data to confirm the alien status of S. istiblenni in Hawai'i. Using molecular sequence data we show that S. istiblenni from Hawai'i are genetically affiliated with source populations in French Polynesia, and not parasites at a geographically intermediate location in the Line Islands. S. istiblenni from Hawai'i are a genetic subset of the more diverse source populations, indicating a bottleneck at introduction. Ecological surveys indicate that the parasite has found suitable intermediate hosts in Hawai'i, which are required for the completion of its life cycle, and that the parasite is twice as prevalent in Hawaiian Bluestripe Snappers as in source populations. While the introduced snapper has spread across the entire 2600 km archipelago to Kure Atoll, the introduced parasite has spread only half that distance. However, the parasite faces no apparent impediments to invading the entire archipelago, with unknown implications for naïve indigenous Hawaiian fishes and the protected Papahānaumokuākea Marine National Monument.

  15. An invasive fish and the time-lagged spread of its parasite across the Hawaiian archipelago.

    Science.gov (United States)

    Gaither, Michelle R; Aeby, Greta; Vignon, Matthias; Meguro, Yu-ichiro; Rigby, Mark; Runyon, Christina; Toonen, Robert J; Wood, Chelsea L; Bowen, Brian W

    2013-01-01

    Efforts to limit the impact of invasive species are frustrated by the cryptogenic status of a large proportion of those species. Half a century ago, the state of Hawai'i introduced the Bluestripe Snapper, Lutjanus kasmira, to O'ahu for fisheries enhancement. Today, this species shares an intestinal nematode parasite, Spirocamallanus istiblenni, with native Hawaiian fishes, raising the possibility that the introduced fish carried a parasite that has since spread to naïve local hosts. Here, we employ a multidisciplinary approach, combining molecular, historical, and ecological data to confirm the alien status of S. istiblenni in Hawai'i. Using molecular sequence data we show that S. istiblenni from Hawai'i are genetically affiliated with source populations in French Polynesia, and not parasites at a geographically intermediate location in the Line Islands. S. istiblenni from Hawai'i are a genetic subset of the more diverse source populations, indicating a bottleneck at introduction. Ecological surveys indicate that the parasite has found suitable intermediate hosts in Hawai'i, which are required for the completion of its life cycle, and that the parasite is twice as prevalent in Hawaiian Bluestripe Snappers as in source populations. While the introduced snapper has spread across the entire 2600 km archipelago to Kure Atoll, the introduced parasite has spread only half that distance. However, the parasite faces no apparent impediments to invading the entire archipelago, with unknown implications for naïve indigenous Hawaiian fishes and the protected Papahānaumokuākea Marine National Monument.

  16. Comparison of Two Independent Mapping Exercises in the Primeiras and Segundas Archipelago, Mozambique

    Directory of Open Access Journals (Sweden)

    Luisa Teixeira

    2016-01-01

    Full Text Available Production of coral reef habitat maps from high spatial resolution multispectral imagery is common practice and benefits from standardized accuracy assessment methods and many informative studies on the merits of different processing algorithms. However, few studies consider the full production workflow, including factors such as operator influence, visual interpretation and a-priori knowledge. An end-user might justifiably ask: Given the same imagery and field data, how consistent would two independent production efforts be? This paper is a post-study analysis of a project in which two teams of researchers independently produced maps of six coral reef systems of the archipelago of the Primeiras and Segundas Environmental Protected Area (PSEPA, Mozambique. Both teams used the same imagery and field data, but applied different approaches—pixel based vs. object based image analysis—and used independently developed classification schemes. The results offer a unique perspective on the map production process. Both efforts resulted in similar merged classes accuracies, averaging at 63% and 64%, but the maps were distinct in terms of scale of spatial patterns, classification disparities, and in other aspects where the mapping process is reliant on visual interpretation. Despite the difficulty in aligning the classification schemes clear patterns of correspondence and discrepancy were identified. The maps were consistent with respect to geomorphological level mapping (17 out of 30 paired comparisons at more than 75% agreement, and also agreed in the extent of coral containing areas within a difference of 16% across the archipelago. However, more detailed benthic habitat level classes were inconsistent. Mapping of deep benthic cover was the most subjective result and dependent on operator visual interpretation, yet this was one of the results of highest interest for the PSEPA management since it revealed a continuity of benthos between the islands

  17. The terrestrial reptile fauna of the Abrolhos Archipelago: species list and ecological aspects.

    Science.gov (United States)

    Rocha, C F D; Dutra, G F; Vrcibradic, D; Menezes, V A

    2002-05-01

    We have studied the terrestrial reptile fauna of the Abrolhos Archipelago (a group of five islands located ca. 70 km off the southern coast of the State of Bahia, Brazil) and analyze here some of its ecological aspects such as diet, thermal ecology, activity, and some reproductive parameters. Three lizards comprise the archipelago's terrestrial reptile fauna: Tropidurus torquatus (Tropiduridae), Mabuya agilis (Scincidae), and Hemidactylus mabouia (Gekkonidae). The first two are diurnal and the latter is crepuscular/nocturnal (initiating activity at ca. 17:30). The activity period of T. torquatus extended from 5:30 to 18:30 h. Mean field body temperatures of active T. torquatus, M. agilis, and H. mabouia were, respectively, 34.0 +/- 3.7 degrees C (range 23.8-38.0 degrees C; N = 75), 34.5 +/- 2.2 degrees C (range 30.8-37.0 degrees C; N = 6), and 26.3 +/- 1.1 degrees C (range 24.8-28.0 degrees C; N = 8). The predominant prey items in the diet of T. torquatus were ants, coleopterans, and hemipterans. In the diet of M. agilis, coleopterans were the most frequent prey items. For H. mabouia, the most important dietary items were orthopterans. Clutch size of T. torquatus averaged 4.1 +/- 1.1 (range 2-6; N = 15) and was significantly related to female size (R2 = 0.618; p = 0.001; N = 15). Clutch size for H. mabouia was fixed (two) and mean litter size of the viviparous M. agilis was 3.3 +/- 0.6 (range 3-4; N = 3). Tropidurus torquatus and H. mabouia deposit their eggs under rocks in the study area, with the former burying them but not the latter; in both species, more than one female often oviposit under the same rock.

  18. Reconstructing decades of glacial mass loss in the Canadian Arctic Archipelago

    Science.gov (United States)

    Noël, Brice; van de Berg, Willem Jan; Lhermitte, Stef; Wouters, Bert; van den Broeke, Michiel

    2017-04-01

    The Canadian Arctic Archipelago (CAA) comprises multiple small glaciers and ice caps mostly concentrated on Ellesmere and Baffin Islands situated in the north (NCAA) and south (SCAA) of the archipelago, respectively. Because they cover a relatively small area and show complex geometries, current regional climate models, generally running at 5 to 20 km horizontal resolution, struggle to accurately resolve surface mass change patterns. Here, we present a 58-year (1958-2015) reconstruction of daily, 1 km surface mass balance (SMB) of the CAA, statistically downscaled from the output of the regional climate model RACMO2.3 at 11 km. By correcting for biases in elevation and ice albedo, the downscaling method significantly improves mass loss estimates over narrow outlet glaciers and isolated ice fields through better resolved marginal meltwater runoff. During the last two decades, CAA glaciers have experienced warmer conditions (+1.1°C) resulting in continued mass loss. NCAA and SCAA mass loss accounted for -24.7 ± 18.0 Gt yr-1 and -21.9 ± 8.2 Gt yr-1 respectively, almost tripling (-8.4 Gt yr-1) and doubling (-11.8 Gt yr-1) the 1958-1995 average. Following the recent warming, enhanced meltwater production reduced the refreezing capacity of inland firn layers by about 6%. While the interior of NCAA ice caps can still buffer most of the additional melt, the lack of a perennial firn area over low-lying SCAA glaciers caused uninterrupted mass loss since the 1980s, which, in the absence of significant refreezing capacity, indicates inevitable disappearance of these highly sensitive glaciers.

  19. The first paleomagnetic data on dolerites from Jeannette Island (New Siberian Islands, Arctic)

    Science.gov (United States)

    Zhdanova, A. I.; Metelkin, D. V.; Vernikovsky, V. A.; Matushkin, N. Yu.

    2016-06-01

    The first paleomagnetic data on dolerite dikes from the volcanogenic-sedimentary section of Jeannette Island (De Long Archipelago, New Siberian Islands) are discussed. The petromagnetic data and results of the baked contact and fold tests are used to substantiate the nature of the characteristic magnetization component, which in combination with the 40Ar/39Ar dates implies its likely Late Precambrian-Early Paleozoic age. The calculated paleomagnetic pole makes it possible to extend the trajectory of the apparent polar movement for the New Siberian Islands block and confirms the assumption that this structural element of the Arctic shelf evolved as a terrane. Two variants of paleotectonic interpretation of the obtained data and their consistency with the available data on the geology and tectonics of the New Siberian Islands are considered.

  20. Long term mass changes and interannual variability in the Canadian Archipelago and Gulf of Alaska from GRACE

    Science.gov (United States)

    Harig, C.; Simons, F. J.

    2015-12-01

    The mass transfer from land ice to the oceans is a major contributor to global sea-level rise. The glaciated regions of the Canadian Archipelago and the Gulf of Alaska are the next largest ice mass loss contributors outside of the Greenland and Antarctic ice sheets. Here we estimate the ice mass change of these regions since 2003 using time-variable gravity data from the GRACE mission. We employ an estimation technique based on spherical Slepian localization functions. These Slepian functions form a sparse set of orthogonal basis functions for a specific region and maximize the signal-to-noise levels of the gravity fields, making them excellent candidates to analyze regional data on the sphere.Between 2003 and 2012 Ellesmere Island lost mass (-38 Gt/yr) at an accelerating rate (-8 Gt/yr2), while Baffin Island lost mass at a lower rate (-22 Gt/yr) with very low acceleration. During this time, interannual variations were well described by an average seasonal cycle. Since 2013 ice mass in Ellesmere and Baffin islands, as well as Greenland, have diverged from their long term mass change trends. During the summer of 2013 these areas had the lowest recorded melt since the start of the GRACE mission. Through the end of 2014, the difference between the observed mass and the extrapolated long term trend for Greenland grew to over 500 gigatons. In contrast to the Canadian Archipelago, the Gulf of Alaska region has average seasonal mass variations four times larger per unit area and greater variability from year to year. Recent years of below average mass loss have lowered the average mass loss rate from previous estimates.

  1. Conditions of the alimentation and the variability of glaciers of the Severnaya Zemlya Archipelago from observations of 2014–2015

    Directory of Open Access Journals (Sweden)

    D. Yu. Bolshiyanov

    2016-01-01

    Full Text Available Glaciological investigations on the Severnaya Zemlya archipelago were resumed in 2013 when a new research station «Ice base Cape Baranova» had been organized by Arctic and Antarctic Research Institute in the North-West of the Island Bolshevik. In 2014–2015, the glaciological polygon named after Leonid Govorukha was established on glaciers Mushketov and Semenov-Tyan-Shanskiy. Two years of observations on the glaciers allowed us to estimate the mass balance of the Mushketov Glacier, which was positive in the 2013–2015. By the end of the melting periods, a superimposed ice was formed on the glacier with thickness of 4 cm in 2014 and 17 cm in 2015, on the average. A snow-firn mass with its vertical thickness exceeding 3 m had been found on the upper part of the Semenov-Tyan-Shansky Glacier. Based on analyses of summer air temperatures and precipitation at the meteorological station «The Golomyanny Island», we assumed that in 2013–2015 the mass balance was also positive on the other glaciers of the archipelago, located to the North of the studied glaciers on the Island of Bolshevik. Data of remote sensing of the catastrophic advancing of the outlet glacier from the Vavilov Ice Cap, obtained in 2013–2016, testify that for much longer period, i.e. during 25 years, conditions for the ice mass accumulation were favorable on the southern and eastern slopes of the Vavilov Ice Cap.

  2. The genus Alvania on the Canary Islands and Madeira (Mollusca: Gastropoda) Part 1

    NARCIS (Netherlands)

    Moolenbeek, R.G.; Hoenselaar, H.J.

    1989-01-01

    Micromolluscs of the family Rissoidae and belonging to the genus Alvania s.l. from the Canary Islands and the Madeira archipelago are revised. For several species the type locality is restricted and lectotypes are designated for Rissoa canadensis d’Orbigny, 1839, R. euchila Watson, 1886, R.

  3. The genus Alvania on the Canary islands and Madeira (Mollusca: Gastropoda), part 2 [final part

    NARCIS (Netherlands)

    Moolenbeek, R.G.; Hoenselaar, H.J.

    1998-01-01

    Five Alvania species from the Canary Islands and the Madeira Archipelago are revised. A new species to science, A. johannae is described and for three species lectotypes are designated. Altogether 13 littoral alvaniids are presently known from this area. Doubtful records are enumerated and a list of

  4. Marine interstitial Amphipoda and Isopoda (Crustacea) from Santiago, Cape Verde Islands

    NARCIS (Netherlands)

    Stock, Jan H.; Vonk, Ronald

    1992-01-01

    Three species of Amphipoda are recorded from interstices of a marine beach on the island of Santiago, Cape Verde Archipelago: Cabogidiella littoralis n. gen., n. sp. (Bogidiellidae), Psammogammarus spinosus n. sp. (Melitidae), and Idunella sketi Karaman, 1980 (Liljeborgiidae). The latter, widely dis

  5. The genus Alvania on the Canary islands and Madeira (Mollusca: Gastropoda), part 2 [final part

    NARCIS (Netherlands)

    Moolenbeek, R.G.; Hoenselaar, H.J.

    1998-01-01

    Five Alvania species from the Canary Islands and the Madeira Archipelago are revised. A new species to science, A. johannae is described and for three species lectotypes are designated. Altogether 13 littoral alvaniids are presently known from this area. Doubtful records are enumerated and a list of

  6. Streptaxidae (Mollusca: Gastropoda: Pulmonata) of the Seychelles Islands, Western Indian Ocean

    NARCIS (Netherlands)

    Gerlach, J.; Bruggen, van A.C.

    1999-01-01

    The taxonomy of the species of the terrestrial carnivorous snail family Streptaxidae of the Seychelles archipelago is reviewed with the exception of the three species of the genus Priodiscus (vide Gerlach, 1995). All 18 species are restricted to the northern, granitic islands. This paper describes 1

  7. Structure refinement of Ag-free heyrovskýite from Vulcano (Aeolian Islands, Italy)

    DEFF Research Database (Denmark)

    Pinto, Daniella; Balic Zunic, Tonci; Garavelli, Anna;

    2011-01-01

    -bearing heyrovskýite structures shows that during the 2 Pb ¿ Ag(Cu)+Bi substitution the increased content of Bi is incorporated preferentially in the Me5 site until 2/3 Bi occupancy and thereafter in the two central octahedrally coordinated sites (Me2 and Me3). Silver occupies exclusively marginal octahedrally...

  8. The marine digital terrain model of the Panarea caldera (Aeolian Islands, Southern Italy

    Directory of Open Access Journals (Sweden)

    M. Anzidei

    1998-06-01

    Full Text Available A Marine Digital Elevation Model (MDEM of the still active volcanic area of Panarea caldera is presented in this paper. A fast and accurate survey was performed by means of the Differential Global Positioning System (DGPS geodetic technique coupled with an echo-sounding gear and a real time navigation software. The instrumentation was installed on board of a low draught boat in order to collect data starting from the bathymeter of one meter. Planar positions and depths were obtained with average accuracies of 30 cm and 10 cm respectively providing a 3D map of the seafloor useful for geomorphological, geophysical and volcanic hazard applications.

  9. Granulometric profiling of aeolian dust deposits by automated image analysis

    Science.gov (United States)

    Varga, György; Újvári, Gábor; Kovács, János; Jakab, Gergely; Kiss, Klaudia; Szalai, Zoltán

    2016-04-01

    Determination of granulometric parameters is of growing interest in the Earth sciences. Particle size data of sedimentary deposits provide insights into the physicochemical environment of transport, accumulation and post-depositional alterations of sedimentary particles, and are important proxies applied in paleoclimatic reconstructions. It is especially true for aeolian dust deposits with a fairly narrow grain size range as a consequence of the extremely selective nature of wind sediment transport. Therefore, various aspects of aeolian sedimentation (wind strength, distance to source(s), possible secondary source regions and modes of sedimentation and transport) can be reconstructed only from precise grain size data. As terrestrial wind-blown deposits are among the most important archives of past environmental changes, proper explanation of the proxy data is a mandatory issue. Automated imaging provides a unique technique to gather direct information on granulometric characteristics of sedimentary particles. Granulometric data obtained from automatic image analysis of Malvern Morphologi G3-ID is a rarely applied new technique for particle size and shape analyses in sedimentary geology. Size and shape data of several hundred thousand (or even million) individual particles were automatically recorded in this study from 15 loess and paleosoil samples from the captured high-resolution images. Several size (e.g. circle-equivalent diameter, major axis, length, width, area) and shape parameters (e.g. elongation, circularity, convexity) were calculated by the instrument software. At the same time, the mean light intensity after transmission through each particle is automatically collected by the system as a proxy of optical properties of the material. Intensity values are dependent on chemical composition and/or thickness of the particles. The results of the automated imaging were compared to particle size data determined by three different laser diffraction instruments

  10. Islands of the Arctic

    Science.gov (United States)

    Dowdeswell, Julian; Hambrey, Michael

    2002-11-01

    The Arctic islands are characterized by beautiful mountains and glaciers, in which the wildlife lives in delicate balance with its environment. It is a fragile region with a long history of exploration and exploitation that is now experiencing rapid environmental change. All of these themes are explored in Islands of the Arctic, a richly illustrated volume with superb photographs from the Canadian Arctic archipelago, Greenland, Svalbard and the Russian Arctic. It begins with the various processes shaping the landscape: glaciers, rivers and coastal processes, the role of ice in the oceans and the weather and climate. Julian Dowdeswell and Michael Hambrey describe the flora and fauna in addition to the human influences on the environment, from the sustainable approach of the Inuit, to the devastating damage inflicted by hunters and issues arising from the presence of military security installations. Finally, they consider the future prospects of the Arctic islands Julian Dowdeswell is Director of the Scott Polar Research Institute and Professor of Physical Geography at 0he University of Cambridge. He received the Polar Medal from Queen Elizabeth for his contributions to the study of glacier geophysics and the Gill Memorial Award from the Royal Geographical Society. He is chair of the Publications Committee of the International Glaciological Society and head of the Glaciers and Ice Sheets Division of the International Commission for Snow and Ice. Michael Hambrey is Director of the Centre for Glaciology at the University of Wales, Aberystwyth. A past recipient of the Polar Medal, he was also given the Earth Science Editors' Outstanding Publication Award for Glaciers (Cambridge University Press). Hambrey is also the author of Glacial Environments (British Columbia, 1994).

  11. Intrathermocline eddies at the Juan Fernández Archipelago, southeastern Pacific

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    Isabel Andrade

    2014-10-01

    Full Text Available Regional Ocean Modeling System (ROMS results, combined with chlorophyll-α (Chl-α and satellite altimetry information as well as information from oceanographic cruises were analyzed to identify interactions between intrathermocline eddies (ITEs and the Juan Fernández Archipelago (JFA, and discuss their potential impact on surface Chl-α concentrations. The JFA is located off the coast of central Chile (33°S, and is composed of three main islands: Robinson Crusoe (RC, Alejandro Selkirk (AS and Santa Clara (SC. Results indicate that the surface and subsurface anticyclonic eddies that interact with the JFA are formed primarily within the coastal transition zone between 33° and 39°S. ITEs are present within the JFA region with a semiannual frequency, mainly during the austral autumn, and have a weak surface expression in relation to the adjacent surface eddies, with a slow displacement (1.16 to 1.4 km d-1 in a northwest direction and a coherent structure for periods of ≥ 1 year. During the ITEs' interaction with RC-SC islands and an adjacent seamount, a slight (prominent thermocline deflection of the upper limit (lower was observed. The horizontal extent (~70-100 km was greater than the internal Rossby deformation radius and the average vertical extent was ~400 m. The interaction between the weak surface expression of ITEs, identified with satellite altimetry, and the JFA persisted during autumn for nine weeks until reaching the winter period. Approximately one month after the beginning of the interaction between ITEs and the islands, increases in surface Chl-α associated with the eddy were observed, with values up to three times higher than adjacent oceanic waters.

  12. Genetically depauperate in the continent but rich in oceanic islands: Cistus monspeliensis (Cistaceae in the Canary Islands.

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    Mario Fernández-Mazuecos

    Full Text Available BACKGROUND: Population genetic theory holds that oceanic island populations are expected to have lower levels of genetic variation than their mainland counterparts, due to founder effect after island colonization from the continent. Cistus monspeliensis (Cistaceae is distributed in both the Canary Islands and the Mediterranean region. Numerous phylogenetic results obtained in the last years allow performing further phylogeographic analyses in Cistus. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed sequences from multiple plastid DNA regions in 47 populations of Cistus monspeliensis from the Canary Islands (21 populations and the Mediterranean basin (26 populations. The time-calibrated phylogeny and phylogeographic analyses yielded the following results: (1 a single, ancestral haplotype is distributed across the Mediterranean, whereas 10 haplotypes in the Canary Islands; (2 four haplotype lineages are present in the Canarian Islands; (3 multiple colonization events across the archipelago are inferred; (4 the earliest split of intraspecific lineages occurred in the Early to Middle Pleistocene (<930,000 years BP. CONCLUSIONS/SIGNIFICANCE: The contrasting pattern of cpDNA variation is best explained by genetic bottlenecks in the Mediterranean during Quaternary glaciations, while the Canarian archipelago acted as a refugium of high levels of genetic diversity. Active colonization across the Canarian islands is supported not only by the distribution of C. monspeliensis in five of the seven islands, but also by our phylogeographic reconstruction in which unrelated haplotypes are present on the same island. Widespread distribution of thermophilous habitats on every island, as those found throughout the Mediterranean, has likely been responsible for the successful colonization of C. monspeliensis, despite the absence of a long-distance dispersal mechanism. This is the first example of a plant species with higher genetic variation among oceanic island

  13. Genetically depauperate in the continent but rich in oceanic islands: Cistus monspeliensis (Cistaceae) in the Canary Islands.

    Science.gov (United States)

    Fernández-Mazuecos, Mario; Vargas, Pablo

    2011-02-14

    Population genetic theory holds that oceanic island populations are expected to have lower levels of genetic variation than their mainland counterparts, due to founder effect after island colonization from the continent. Cistus monspeliensis (Cistaceae) is distributed in both the Canary Islands and the Mediterranean region. Numerous phylogenetic results obtained in the last years allow performing further phylogeographic analyses in Cistus. We analyzed sequences from multiple plastid DNA regions in 47 populations of Cistus monspeliensis from the Canary Islands (21 populations) and the Mediterranean basin (26 populations). The time-calibrated phylogeny and phylogeographic analyses yielded the following results: (1) a single, ancestral haplotype is distributed across the Mediterranean, whereas 10 haplotypes in the Canary Islands; (2) four haplotype lineages are present in the Canarian Islands; (3) multiple colonization events across the archipelago are inferred; (4) the earliest split of intraspecific lineages occurred in the Early to Middle Pleistocene (<930,000 years BP). The contrasting pattern of cpDNA variation is best explained by genetic bottlenecks in the Mediterranean during Quaternary glaciations, while the Canarian archipelago acted as a refugium of high levels of genetic diversity. Active colonization across the Canarian islands is supported not only by the distribution of C. monspeliensis in five of the seven islands, but also by our phylogeographic reconstruction in which unrelated haplotypes are present on the same island. Widespread distribution of thermophilous habitats on every island, as those found throughout the Mediterranean, has likely been responsible for the successful colonization of C. monspeliensis, despite the absence of a long-distance dispersal mechanism. This is the first example of a plant species with higher genetic variation among oceanic island populations than among those of the continent.

  14. Community structures of soil animals and survival of land snails on an island of the Ogasawara Archipelago Estruturas de comunidades de animais de solo e sobrevivência dos caracóis terrestres numa ilha do Arquipélago Ogasawara

    Directory of Open Access Journals (Sweden)

    Motohiro Hasegawa

    2009-08-01

    Full Text Available On Chichijima, one of the Ogasawara (Bonin Islands located in the Western Pacific Ocean, land snails have declined, the suggested cause being predation pressure by an invasive flatworm (Platydemus manokwari. Soil fauna were investigated in areas where the snail survives, and where it has become extinct. Much of the fauna, dominated by introduced earthworms and ants, was undiminished, however, one undescribed but endemic carabid (Badister sp., which selectively feeds on land snails, was absent in snail-extinct areas. The invasive flatworm P. manokwari has been reported to feed also on the carcasses of earthworms, as well as on live snails, and is therefore expected to occur in most parts of Chichijima Island. Among other groups, the density of isopods (also dominated by exotic species was very low, in comparison with the reported ones 30 years ago. Community structure is currently reflected by dominance of earthworms and ants, decline of endemic isopods, and a high frequency of introduced or alien species.Em Chichijima, uma das ilhas do Arquipélago Ogasawara (Bonin, localizado no Oceano Pacífico Ocidental, o número de caracóis terrestres diminuiu, e a causa provável é a predação por uma planária invasora (Platydemus manokwari. A fauna edáfica foi avaliada nas áreas onde o caracol sobreviveu e onde se extinguiu. Grande parte da fauna, dominada inicialmente por minhocas e formigas, não diminuiu; contudo, um carabídeo endêmico e não descrito (Badister sp., que se alimenta de caracóis terrestres, não estava presente nas áreas em que o caracol foi extinto. Sabe-se que a planária invasiva P. manokwari se alimenta não só das carcaças das minhocas, mas também de caracóis vivos, e por isso habita a maior parte da Ilha Chichijima. Entre outros grupos, a densidade de isópodos (também dominados por espécies exóticas foi muita baixa, em comparação aos relatos feitos 30 anos antes. A estrutura da comunidade é refletida atualmente

  15. Raccoon removal reduces sea turtle nest depredation in the Ten Thousand Islands of Florida

    Science.gov (United States)

    Garmestani, A.S.; Percival, H.F.

    2005-01-01

    Predation by raccoons, Procyon lotor marinus (L.), is the primary cause of sea turtle nest loss in the Ten Thousand Islands archipelago. Four islands within Ten Thousand Islands National Wildlife Refuge were surveyed for sea turtle nesting activity from 1991-95. Raccoons depredated 76-100% of nests on Panther Key from 1991-94, until 14 raccoons were removed in 1995 resulting in 0% depredation and 2 more were removed in 1996 resulting in 0% depredation. Raccoon removal may be an effective management option for increasing sea turtle nest survival on barrier islands.

  16. Bats of the Western Indian Ocean Islands

    Directory of Open Access Journals (Sweden)

    John O’Brien

    2011-08-01

    Full Text Available The natural colonisation of many remote oceanic islands by bats, including those of the western Indian Ocean, has been facilitated by their unique capability among mammals for powered flight. In the western Indian Ocean region, only the Malagasy islands of Madagascar and the Comoros archipelago have been naturally colonised by non-volant mammals. Despite their greater potential for inter-island dispersal, and thus gene transfer, endemicity of Chiroptera in the western Indian Ocean islands is high. Given their vulnerability to stochastic and anthropogenic disturbances, greater focus needs to be placed on investigating the demographic and ecological history of bats on Western Indian Ocean islands to safeguard not only their future, but also the ecosystem functioning on these islands, for which they are undoubtedly such an integral part. Here, I summarise the taxonomic and life history information available on bats from Western Indian Ocean islands and highlight knowledge gaps and conservation issues that threaten the continued persistence of some species.

  17. Spatiotemporal Structure of Aeolian Particle Transport on Flat Surface

    Science.gov (United States)

    Niiya, Hirofumi; Nishimura, Kouichi

    2017-05-01

    We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from 10-5 to 10 m above the flat surface. The numerical results are as follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below 10 cm and gradual wind response above 10 cm. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below 100 µm remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above 300 µm is less than the wind speed, whereas that below 300 µm exceeds the wind speed because of descending particles. (v) The particle diameter increases with height in the saltation layer, and the relationship is expressed as a power function. Through comparisons with the previously reported random-flight model, we find a crucial problem that empirical splash functions cannot reproduce particle dynamics at a relatively high wind speed.

  18. Spatiotemporal Structure of Aeolian Particle Transport on Flat Surface

    CERN Document Server

    Niiya, Hirofumi

    2016-01-01

    We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from $10^{-5} \\hspace{0.5 ex} \\mathrm{m}$ to $10 \\hspace{0.5 ex} \\mathrm{m}$ above the flat surface. The numerical results are s follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below $10 \\hspace{0.5 ex} \\mathrm{cm}$ and gradual wind response above $10 \\hspace{0.5 ex} \\mathrm{cm}$. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below $100 \\hspace{0.5 ex} \\mu\\mathrm{m}$ remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above $300 \\hspace{0.5 ex} \\mu\\mathrm{m}$ is less than the wind speed, whereas that below $300 \\hspace{0.5 ex} \\mu\\mathrm...

  19. Protocols for characterizing aeolian mass-flux profiles

    Science.gov (United States)

    Ellis, J. T.; Li, B.; Farrell, E. J.; Sherman, D. J.

    This paper describes a protocol for characterizing and analyzing the vertical mass-flux profiles above erodible beds in natural aeolian environments. Three main areas of methodological inconsistencies are explored, using two field data sets, to demonstrate the variability of results caused by methodological choices associated with: (1) inconsistent representation of sediment trap elevations; (2) erroneous or sub-optimal regression analysis; and (3) inadequate or ambiguous bed elevation measurements. The recommended methodology is physically based, produces results that most closely represent the measured data, and will permit results from different field and laboratory studies to be compared using a standardized convention. The recommended protocol suggests the following: (1) measure vertical flux profiles with as many traps as feasible with shorter traps near the bed; (2) measure bed elevation before, during, and after data collection; (3) use the geometric mean to represent trap centers; (4) use the saltation-enhanced aerodynamic roughness length when approximating the bottom elevation of traps deployed at the bed (0 mm); (5) plot vertical mass-flux data with height above the bed as the independent variable; and (6) fit vertical mass-flux curves using non-linear, exponential curve fitting.

  20. The birth and death of transverse aeolian ridges on Mars

    Science.gov (United States)

    Geissler, Paul E.

    2014-01-01

    Transverse aeolian ridges (TARs) are small bright windblown deposits found throughout the Martian tropics that stand a few meters tall and are spaced a few tens of meters apart. The origin of these features remains mysterious more than 20 years after their discovery on Mars. This paper presents a new hypothesis, that some of the TARs could be indurated dust deposits emplaced millions of years ago during periods of higher axial obliquity. It suggests that these TARs are primary depositional bed forms that accumulated in place from dust carried by the winds in suspension, perhaps in a manner comparable to antidunes on Earth, and were subsequently indurated and eroded to their current states by eons of sandblasting. It points out examples of modern dust drifts and dune-like features that appear to have been recently formed by dust accumulating directly onto the surface from atmospheric suspension. It shows how these pristine dust deposits could evolve to explain the range of morphologies of the TARs. Finally, it explains how the known properties of many TARs are consistent with this hypothesis, including their composition, thermal behavior, and distribution.

  1. Balancing water, religion and tourism on Redang Island, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Joshua B [Environmental Change Institute, School of Geography and the Environment, Oxford University, South Parks Road, Oxford OX1 0EZ (United Kingdom); Nawaz, Rizwan; Nawaz, Faiza [HydroRisk Ltd, Leeds University Union, Lifton Place, University of Leeds, Leeds LS2 9JT (United Kingdom); Fauzi, Rosmadi [Department of Geography, Universiti Malaya, 50603 Kuala Lumpur (Malaysia); Sadek, Eran Sadek Said Md; Latif, Zulkiflee Abd [Department of Surveying Science and Geomatics, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Blackett, Matthew [Department of Geography, King' s College London, Strand, London WC2R 2LS (United Kingdom)], E-mail: joshbfisher@gmail.com

    2008-04-15

    Redang Island (Pulau Redang) is an island off of Peninsular Malaysia that is part of a Marine Park archipelago of corals and thousands of fish and invertebrates. The relatively isolated local community is generally centered on fishing, and Islam guides daily life. Recently, the tourism industry has expanded on the island. New hotels and resorts provide jobs, but also expose the locals to western culture and touristic behavior, which may clash with deeply traditional community values. Further, the tourism industry may be putting a strain on the natural resources, especially the quantity and quality of freshwater. The island village may become divided between those who support the tourism industry and those who do not. Here we present an exploratory investigation into the development-environment-culture dynamics of tourism, water and religion on Redang Island while building collaborations between universities of this Muslim state and the West.

  2. Balancing water, religion and tourism on Redang Island, Malaysia

    Science.gov (United States)

    Fisher, Joshua B.; Nawaz, Rizwan; Fauzi, Rosmadi; Nawaz, Faiza; Sadek, Eran Sadek Said Md; Abd Latif, Zulkiflee; Blackett, Matthew

    2008-04-01

    Redang Island (Pulau Redang) is an island off of Peninsular Malaysia that is part of a Marine Park archipelago of corals and thousands of fish and invertebrates. The relatively isolated local community is generally centered on fishing, and Islam guides daily life. Recently, the tourism industry has expanded on the island. New hotels and resorts provide jobs, but also expose the locals to western culture and touristic behavior, which may clash with deeply traditional community values. Further, the tourism industry may be putting a strain on the natural resources, especially the quantity and quality of freshwater. The island village may become divided between those who support the tourism industry and those who do not. Here we present an exploratory investigation into the development environment culture dynamics of tourism, water and religion on Redang Island while building collaborations between universities of this Muslim state and the West.

  3. Birth of two volcanic islands in the southern Red Sea

    KAUST Repository

    Xu, Wenbin

    2015-05-26

    Submarine eruptions that lead to the formation of new volcanic islands are rare and far from being fully understood; only a few such eruptions have been witnessed since Surtsey Island emerged to the south of Iceland in the 1960s. Here we report on two new volcanic islands that were formed in the Zubair archipelago of the southern Red Sea in 2011–2013. Using high-resolution optical satellite images, we find that the new islands grew rapidly during their initial eruptive phases and that coastal erosion significantly modified their shapes within months. Satellite radar data indicate that two north–south-oriented dykes, much longer than the small islands might suggest, fed the eruptions. These events occurred contemporaneously with several local earthquake swarms of the type that typically accompany magma intrusions. Earthquake activity has been affecting the southern Red Sea for decades, suggesting the presence of a magmatically active zone that has previously escaped notice.

  4. Aeolian sedimentary processes at the Bagnold Dunes, Mars: Implications for modern dune dynamics and sedimentary structures in the aeolian stratigraphic record of Mars

    Science.gov (United States)

    Ewing, Ryan C.; Bridges, Nathan T.; Sullivan, Rob; Lapotre, Mathieu G. A.; Fischer, Woodward W.; Lamb, Mike P.; Rubin, David M.; Lewis, Kevin W.; Gupta, Sanjeev

    2016-04-01

    Wind-blown sand dunes are ubiquitous on the surface of Mars and are a recognized component of the martian stratigraphic record. Our current knowledge of the aeolian sedimentary processes that determine dune morphology, drive dune dynamics, and create aeolian cross-stratification are based upon orbital studies of ripple and dune morphodynamics, rover observations of stratification on Mars, Earth analogs, and experimental and theoretical studies of sand movement under Martian conditions. In-situ observations of sand dunes (informally called the Bagnold Dunes) by Curiosity Rover in Gale Crater, Mars provide the first opportunity to make observations of dunes from the grain-to-dune scale thereby filling the gap in knowledge between theory and orbital observations and refining our understanding of the martian aeolian stratigraphic record. We use the suite of cameras on Curiosity, including Navigation Camera (Navcam), Mast Camera (Mastcam) and Mars Hand Lens Imager (MAHLI), to make observations of the Bagnold Dunes. Measurements of sedimentary structures are made where stereo images are available. Observations indicate that structures generated by gravity-driven processes on the dune lee slopes, such as grainflow and grainfall, are similar to the suite of aeolian sedimentary structures observed on Earth and should be present and recognizable in Mars' aeolian stratigraphic record. Structures formed by traction-driven processes deviate significantly from those found on Earth. The dune hosts centimeter-scale wind ripples and large, meter-scale ripples, which are not found on Earth. The large ripples migrate across the depositional, lee slopes of the dune, which implies that these structures should be present in Mars' stratigraphic record and may appear similar to compound-dune stratification.The Mars Science Laboratory Curiosity Rover Team is acknowledged for their support of this work.

  5. Extent of mangrove nursery habitats determines the geographic distribution of a coral reef fish in a South-Pacific archipelago.

    Directory of Open Access Journals (Sweden)

    Christelle Paillon

    Full Text Available Understanding the drivers of species' geographic distribution has fundamental implications for the management of biodiversity. For coral reef fishes, mangroves have long been recognized as important nursery habitats sustaining biodiversity in the Western Atlantic but there is still debate about their role in the Indo-Pacific. Here, we combined LA-ICP-MS otolith microchemistry, underwater visual censuses (UVC and mangrove cartography to estimate the importance of mangroves for the Indo-Pacific coral reef fish Lutjanus fulviflamma in the archipelago of New Caledonia. Otolith elemental compositions allowed high discrimination of mangroves and reefs with 83.8% and 98.7% correct classification, respectively. Reefs were characterized by higher concentrations of Rb and Sr and mangroves by higher concentrations of Ba, Cr, Mn and Sn. All adult L. fulviflamma collected on reefs presented a mangrove signature during their juvenile stage with 85% inhabiting mangrove for their entire juvenile life (about 1 year. The analysis of 2942 UVC revealed that the species was absent from isolated islands of the New Caledonian archipelago where mangroves were absent. Furthermore, strong positive correlations existed between the abundance of L. fulviflamma and the area of mangrove (r = 0.84 for occurrence, 0.93 for density and 0.89 for biomass. These results indicate that mangrove forest is an obligatory juvenile habitat for L. fulviflamma in New Caledonia and emphasize the potential importance of mangroves for Indo-Pacific coral reef fishes.

  6. Spatio-temporal variation in the diet of Cory's shearwater Calonectris diomedea in the Azores archipelago, northeast Atlantic

    Science.gov (United States)

    Neves, Verónica; Nolf, Dirk; Clarke, Malcolm

    2012-12-01

    The diet of Cory's shearwater Calonectris diomedea in the Azores was studied in four islands of the archipelago over four breeding seasons, using stomach flushings from 959 birds. Fish were identified from flesh, otoliths and vertebrae and cephalopods from flesh and lower beaks. The frequency of occurrence of prey taxa, and the numerical frequency of fish and cephalopods, showed marked variations both spatially, across the breeding cycle and between years. Overall, cephalopods from 37 species representing 17 families and fish from 33 species representing 18 families were identified, representing over 70 prey species and trebling what was previously known. Histioteuthidae, Ommastrephidae and Cranchiidae were the only cephalopod families present every year and represented two thirds of the cephalopods' consumption by number. Blue jack mackerel Trachurus picturatus was the most abundant prey species present in 1998 and 2002 but was absent in 1999 and 2000, representing on average 57.2% of prey by number in the years it occurred. Apart from blue jack mackerel, most fish species were present in very low numbers with the exception of Cubiceps gracilis, Scomberesox saurus and Maurolicus muellerii. Diaphus adenomus, was recorded for the first time for the Azores archipelago.

  7. Portuguese migration to the Canary Islands: an analysis based on surnames.

    Science.gov (United States)

    Román-Busto, J; Fuster, V; Colantonio, S E

    2012-01-01

    As a part of a wider analysis of population and genetic exchange between Spain and Portugal, the long-term pattern of Portuguese immigration to the Canary Islands was studied by means of the frequency of Portuguese surnames. A database of 1,995,833 individuals was obtained from the Spanish National Statistics Institute (2006). Among the 826 most frequent surnames to appear, 79 surnames of Portuguese origin were selected. The distribution of these surnames by municipalities and islands, the Fisher index of diversity, and the Lasker inter-population relationship coefficients R(ij) were considered. These coefficients were inter-correlated and correlated with other variables that could have influenced the distribution of surnames. From the observed distribution of the frequency of surnames, a non-random migration pattern conditioned by economic factors was found. The greatest diversity of surnames existed in cane cultivating areas after the first arrival of Portuguese immigrants. A later dispersion of surnames among islands was correlated with the inter-island geographic distances. In some islands the arrival of new immigrants continued due to their strategic location within the Canary archipelago. The Canary Islands reveal a high frequency and diversity of Portuguese surnames. The results also prove a heterogeneous distribution of these surnames throughout the archipelago. In contrast to the Portuguese archipelagos, some Canary localities have received immigrants continuously because of their economic importance in sugar cane cultivation and strategic geographic location on the maritime routes to Africa and America.

  8. The Big Island of Hawaii

    Science.gov (United States)

    2002-01-01

    Boasting snow-covered mountain peaks and tropical forest, the Island of Hawaii, the largest of the Hawaiian Islands, is stunning at any altitude. This false-color composite (processed to simulate true color) image of Hawaii was constructed from data gathered between 1999 and 2001 by the Enhanced Thematic Mapper plus (ETM+) instrument, flying aboard the Landsat 7 satellite. The Landsat data were processed by the National Oceanographic and Atmospheric Administration (NOAA) to develop a landcover map. This map will be used as a baseline to chart changes in land use on the islands. Types of change include the construction of resorts along the coastal areas, and the conversion of sugar plantations to other crop types. Hawaii was created by a 'hotspot' beneath the ocean floor. Hotspots form in areas where superheated magma in the Earth's mantle breaks through the Earth's crust. Over the course of millions of years, the Pacific Tectonic Plate has slowly moved over this hotspot to form the entire Hawaiian Island archipelago. The black areas on the island (in this scene) that resemble a pair of sun-baked palm fronds are hardened lava flows formed by the active Mauna Loa Volcano. Just to the north of Mauna Loa is the dormant grayish Mauna Kea Volcano, which hasn't erupted in an estimated 3,500 years. A thin greyish plume of smoke is visible near the island's southeastern shore, rising from Kilauea-the most active volcano on Earth. Heavy rainfall and fertile volcanic soil have given rise to Hawaii's lush tropical forests, which appear as solid dark green areas in the image. The light green, patchy areas near the coasts are likely sugar cane plantations, pineapple farms, and human settlements. Courtesy of the NOAA Coastal Services Center Hawaii Land Cover Analysis project

  9. Genetic structure of the Azores Islands: a study using 15 autosomal short tandem repeat loci.

    Science.gov (United States)

    Santos, Cristina; Alvarez, Luis; Aluja, Maria Pilar; Bruges-Armas, Jacome; Lima, Manuela

    2009-12-01

    The Azores archipelago (Portugal), located in the Atlantic Ocean, 1,500 km from the European mainland, is formed by nine islands of volcanic origin. The relative position of these islands allows the definition of three geographical groups: Eastern, Central and Western. Previous studies of the Azores using Short Tandem Repeats (STRs) have highlighted differences in the frequencies of several loci, when compared to Mainland Portugal or Madleira Island. Furthermore, linkage disequilibrium (LD), described for Azorean samples has been tentatively explained as reflecting the presence of genetic sub-structuring in the archipelago. To provide information concerning the genetic profile of the Azores Islands and to evaluate the presence of substructuring we have determined the allelic frequencies of 15 autosomal STR loci, using the AmpFlSTR Identifiler Kit, in representative samples from the Azorean Islands. Either considering the Azores as a whole, or analysing by island all the loci were in conformity with Hardy-Weinberg equilibrium. Average gene diversity ranged from 0.7669 in Corvo to 0.7972 in Terceira Island. Allelic independence between loci, tested for the global sample, detected significant LD (after correction for multiple tests) for pairs D21S11/D7S820 and D3S1358/D5S818. The exact test of population differentiation, combining the information of the 15 markers analysed, revealed significant differences between the three groups of islands, and between islands. Inter-island analysis reinforces the previous data that suggested the existence of sub-structuring in the Azores archipelago. Moreover, the data generated by this study can be used in a future forensic genetic database of the Azores after the appropriate enlacement of sample size by island, preventing, in that way, misinterpretations caused by population substructuring and small sample sizes.

  10. Islands erased by snow and ice: approaching the spatial philosophy of cold water island imaginaries

    Directory of Open Access Journals (Sweden)

    Johannes Riquet

    2016-05-01

    Full Text Available Representations of islands in Western fiction typically revolve around tropical islands. Critical discourse tends to reproduce this tendency and rarely addresses the specific spatial poetics of cold-water island fictions. This paper discusses three texts that poetically deploy the geographical inventory of northern snow- and icescapes to challenge essentialist assumptions about islands: D. H. Lawrence’s short story “The man who loved islands”, Georgina Harding’s novel The solitude of Thomas Cave, and Michel Serres’s treatise Le passage du Nord-Ouest. It is argued that these texts reflect on the importance of the horizontal and vertical components of material and textual topographies for the conception and experience of islands. In all three, the physical transformation of the islandscapes by snow and ice serves to put the island concept itself into question. Serres’s philosophical text geopoetically portrays the Arctic archipelago of the Northwest Passage to explore the reciprocal relations between language and the material world. In Lawrence and Harding, the snow-covered islands cease to function as economically productive spaces and turn into complex spatial figures offering a philosophical meditation on islandness as a contradictory and multifaceted condition.

  11. The Balearic Islands in the Alpine Orogeny

    Energy Technology Data Exchange (ETDEWEB)

    Bourrouilh, R.

    2016-10-01

    The place of the Balearic Islands in the Alpine orogeny is examined using detailed sedimentology studies, stratigraphical studies from the Lower Devonian (Lochkovian) to modern times and a careful tectonic review of sedimentary formations from the Western Mediterranean. Despite being considered as the ultimate end of the north-eastern termination of the Betic Cordillera, the history of the Balearic archipelago seems to be closer to the tectonic opening of the Gulf of Valencia and to the Corsica-Sardinia rotation, and thus to the tectonic history of the Western Mediterranean Sea, than to the tectonics of the Betic Cordillera which appear as its symmetrical image with respect to this opening. (Author)

  12. Levels and spatial distribution of perfluorinated compounds (PFCs) in superficial sediments from the marine reserves of the Tuscan Archipelago National Park (Italy).

    Science.gov (United States)

    Perra, Guido; Focardi, Silvano Ettore; Guerranti, Cristiana

    2013-11-15

    Surface sediments from marine reserves of the Tuscan Archipelago National Park (Italy), including remote islands not directly affected by anthropogenic influences, were analyzed for two dominant perfluorinated compounds (PFCs), namely perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), using LC-ESI-MS/MS. The concentrations of PFOS were low, with medians ranging from 0.25 to 1.50 ng/g dry wt, whereas PFOA was always below the detection limit of 0.1 ng/g dry wt. The present paper can be considered a baseline study useful in future environmental monitoring programs.

  13. First Harvestman Record for the Juan Fernández Archipelago, Chile, with Morphological Notes on Acropsopilio chilensis (Opiliones: Caddidae: Acroposopilioninae).

    Science.gov (United States)

    Pérez-González, Abel; Ramírez, Martín J; Soto, Eduardo M; Pizarro-Araya, Jaime

    2014-08-15

    Acropsopilio chilensis Silvestri, 1904 (Eupnoi: Caddidae: Acropsopilioninae), is recorded for Robinson Crusoe Island, Chile. This is the first harvestman species recorded for the Juan Fernández Archipelago and also the first extra-continental record for this species. During the comparison with continental co-specific specimens, some previously unknown, remarkable morphological characteristics were discovered, among them: the absence of ovipositor seminal receptacles and tracheal system, small and probably imperforate spiracles and the presence of a subdistal spiny structure, maybe a stylus, in the major branch of the penis. 

  14. Numerical analysis on aeolian vibration of transmission lines with Stockbridge dampers

    Institute of Scientific and Technical Information of China (English)

    LI Li; KONG De-yi; LONG Xiao-hong; FANG Qin-han

    2008-01-01

    We used computational fluid dynamics (CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex. Firstly, we obtained the wind power inputs using CFD theory. The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests. Then a new aeolian excitation was derived using the wind power equivalent principle, and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account. Secondly, we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method. The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps. Finally, the semi-analytical solution can be solved by iterative methods. Taking a 1 000 kV Ultra High Voltage transmission line as an example, we analyzed the line with and without dampers by the semi-analytical solution. Compared with the results which were computed by the energy balance method, the semi-analytical solution is precise enogh for aeolian vibration analyses. Besides, we also analyzed the influence of damper position and quantity.

  15. Aeolian and fluvial processes in dryland regions: the need for integrated studies

    Science.gov (United States)

    Belnap, Jayne; Munson, Seth M.; Field, Jason P.

    2011-01-01

    Aeolian and fluvial processes play a fundamental role in dryland regions of the world and have important environmental and ecological consequences from local to global scales. Although both processes operate over similar spatial and temporal scales and are likely strongly coupled in many dryland systems, aeolian and fluvial processes have traditionally been studied separately, making it difficult to assess their relative importance in drylands, as well as their potential for synergistic interaction. Land degradation by accelerated wind and water erosion is a major problem throughout the world's drylands, and although recent studies suggest that these processes likely interact across broad spatial and temporal scales to amplify the transport of soil resources from and within drylands, many researchers and land managers continue to view them as separate and unrelated processes. Here, we illustrate how aeolian and fluvial sediment transport is coupled at multiple spatial and temporal scales and highlight the need for these interrelated processes to be studied from a more integrated perspective that crosses traditional disciplinary boundaries. Special attention is given to how the growing threat of climate change and land-use disturbance will influence linkages between aeolian and fluvial processes in the future. We also present emerging directions for interdisciplinary needs within the aeolian and fluvial research communities that call for better integration across a broad range of traditional disciplines such as ecology, biogeochemistry, agronomy, and soil conservation.

  16. Observations of several characteristics of aeolian sand movement in the Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    HAN; Zhiwen; DONG; Zhibao; WANG; Tao; CHEN; Guangting; YAN

    2004-01-01

    With both sides of the Taklimakan Desert highway line as the study area, three typical aeolian sand landforms, i.e. complex dune ridge, barchan dune and flat sand land, were selected as sand beds for the observation, analysis and research of the characteristics of aeolian sand movement such as aeolian sand stream structure, sand transport intensity, etc. in the Taklimakan Desert. The results show that there is a linear relation between the height and the log of sand transport rate over transverse dune chain, longitudinal dune ridge and flat sand land, i.e. the sand transport percentage decreases exponentially with increasing height. Sand transport rate within the 10 cm height above the bed surface accounts for 80%-95% of the total sand transport rate of the observed height (40 cm), while the sand transport rate in 20 cm occupies 98% of the total amount. Sand transport rate (g·cm-1·min-1) differs greatly with respect to different landform types and different topographic positions. Based on the investigation and analysis on aeolian sand landform origin, morphological type and distribution feature, the two typical landform assemblages, complex transverse dune chain-alluvial plain and huge longitudinal dune ridge-interridge lowland in the Taklimakan Desert were divided into several characteristic zones of aeolian sand movement states. From this one can qualitatively judge the types and severities of sand disasters at various topographic positions in the engineering installation region and further put forward concrete schemes and measures to control sand damages.

  17. Laboratory studies of aeolian sediment transport processes on planetary surfaces

    Science.gov (United States)

    Rasmussen, Keld R.; Valance, Alexandre; Merrison, Jonathan

    2015-09-01

    We review selected experimental saltation studies performed in laboratory wind tunnels and collision experiments performed in (splash-) laboratory facilities that allow detailed observations between impinging particles on a stationary bed. We also discuss progress in understanding aeolian transport in nonterrestrial environments. Saltation studies in terrestrial wind tunnels can be divided into two groups. The first group comprises studies using a short test bed, typically 1-4 m long, and focuses on the transitional behavior near the upwind roughness discontinuity where saltation starts. The other group focuses on studies using long test beds - typically 6 m or more - where the saturated saltation takes place under equilibrium conditions between wind flow and the underlying rough bed. Splash studies using upscaled model experiments allow collision simulations with large spherical particles to be recorded with a high speed video camera. The findings indicate that the number of ejected particles per impact scales linearly with the impact velocity of the saltating particles. Studies of saturated saltation in several facilities using predominantly Particle Tracking Velocimetry or Laser Doppler Velocimetry indicate that the velocity of the (few) particles having high trajectories increases with increasing friction velocity. However, the speed of the majority of particles that do not reach much higher than Bagnold's focal point is virtually independent of Shields parameter - at least for low or intermediate u*-values. In this case mass flux depends on friction velocity squared and not cubed as originally suggested by Bagnold. Over short beds particle velocity shows stronger dependence on friction velocity and profiles of particle velocity deviate from those obtained over long beds. Measurements using horizontally segmented traps give average saltation jump-lengths near 60-70 mm and appear to be only weakly dependent on friction velocity, which is in agreement with some

  18. Straw Boats and the Proverbial Sea: A Response to 'Island Archaeology: In Search of a New Horizon'

    Directory of Open Access Journals (Sweden)

    Scott M. Fitzpatrick

    2007-11-01

    Full Text Available In a recent ISJ paper, “Island Archaeology: In Search of a New Horizon”, Boomert and Bright (2007 argue that the field of “island archaeology” should be replaced by an “archaeology of maritime identity”. We disagree and counter that although islands share many physical, biological, and cultural similarities with continental coasts, coastal zones also grade uninterruptedly into riverine, lacustrine, and terrestrial landscapes, raising questions about the validity of their concept of the archaeology of maritime identity. In our view, island archaeology (the application of archaeology to island settings, regardless of past biogeographical underpinnings, has made major contributions to understanding the historical ecology, human impacts, and cultural developments of islands around the world. A focus on islands by archaeologists has encouraged scholars to study the history of island and maritime societies within a comparative framework that is useful for breaking out of the often provincial focus on a single island or archipelago.

  19. Distribution and genetic variation of hymenolepidid cestodes in murid rodents on the Canary Islands (Spain

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    Feliu Carlos

    2011-09-01

    Full Text Available Abstract Background In the Canary Islands there are no previous data about tapeworms (Cestoda of rodents. In order to identify the hymenolepidid species present in these hosts, a survey of 1,017 murine (349 Rattus rattus, 13 Rattus norvegicus and 655 Mus musculus domesticus was carried out in the whole Archipelago. Molecular studies based on nuclear ITS1 and mitochondrial COI loci were performed to confirm the identifications and to analyse the levels of genetic variation and differentiation. Results Three species of hymenolepidids were identified: Hymenolepis diminuta, Rodentolepis microstoma and Rodentolepis fraterna. Hymenolepis diminuta (in rats and R. microstoma (in mice showed a widespread distribution in the Archipelago, and R. fraterna was the least spread species, appearing only on five of the islands. The hymenolepidids found on Fuerteventura, Lanzarote and La Graciosa were restricted to one area. The COI network of H. diminuta showed that the haplotypes from Lanzarote and Fuerteventura are the most distant with respect to the other islands, but clearly related among them. Conclusions Founder effects and biotic and abiotic factors could have played important role in the presence/absence of the hymenolepidid species in determined locations. The haplotypes from the eastern islands (Fuerteventura and Lanzarote seem to have shared an ancestral haplotype very distant from the most frequent one that was found in the rest of the islands. Two colonization events or a single event with subsequent isolation and reduced gene flow between western-central and eastern islands, have taken place in the Archipelago. The three tapeworms detected are zoonotic species, and their presence among rodents from this Archipelago suggests a potential health risk to human via environmental contamination in high risk areas. However, the relatively low prevalence of infestations detected and the focal distribution of some of these species on certain islands reduce

  20. Distribution and genetic variation of hymenolepidid cestodes in murid rodents on the Canary Islands (Spain)

    Science.gov (United States)

    2011-01-01

    Background In the Canary Islands there are no previous data about tapeworms (Cestoda) of rodents. In order to identify the hymenolepidid species present in these hosts, a survey of 1,017 murine (349 Rattus rattus, 13 Rattus norvegicus and 655 Mus musculus domesticus) was carried out in the whole Archipelago. Molecular studies based on nuclear ITS1 and mitochondrial COI loci were performed to confirm the identifications and to analyse the levels of genetic variation and differentiation. Results Three species of hymenolepidids were identified: Hymenolepis diminuta, Rodentolepis microstoma and Rodentolepis fraterna. Hymenolepis diminuta (in rats) and R. microstoma (in mice) showed a widespread distribution in the Archipelago, and R. fraterna was the least spread species, appearing only on five of the islands. The hymenolepidids found on Fuerteventura, Lanzarote and La Graciosa were restricted to one area. The COI network of H. diminuta showed that the haplotypes from Lanzarote and Fuerteventura are the most distant with respect to the other islands, but clearly related among them. Conclusions Founder effects and biotic and abiotic factors could have played important role in the presence/absence of the hymenolepidid species in determined locations. The haplotypes from the eastern islands (Fuerteventura and Lanzarote) seem to have shared an ancestral haplotype very distant from the most frequent one that was found in the rest of the islands. Two colonization events or a single event with subsequent isolation and reduced gene flow between western-central and eastern islands, have taken place in the Archipelago. The three tapeworms detected are zoonotic species, and their presence among rodents from this Archipelago suggests a potential health risk to human via environmental contamination in high risk areas. However, the relatively low prevalence of infestations detected and the focal distribution of some of these species on certain islands reduce the general transmission

  1. Characterization of the Corrosive Action of Mineral Waters from Thermal Sources: A Case Study at Azores Archipelago, Portugal

    Directory of Open Access Journals (Sweden)

    Helena Cristina Vasconcelos

    2015-07-01

    Full Text Available Waters from natural sources of the São Miguel Island in the Azores archipelago have been investigated regarding their corrosive action on metallic materials. The corrosive and encrusting characteristics of the waters have been established in terms of relevant chemical parameters (namely pH, conductivity, total dissolved solids (TDS, and concentrations of bicarbonate, calcium, magnesium, chloride, and sulfate ions and their temperature by using Langelier, Ryznar, Puckorius and Larson–Skold indexes. The validity of this methodology has been tested by measuring the corrosion rates of various metals exposed to various waters using electrochemical methods. The materials of industrial interest under investigation were carbon and galvanized steel, zinc, 304 and 316L grade stainless steels, brass, and Cr–Ni alloys. The greater aggressiveness of these waters was found for the less noble materials, and they experienced high corrosion rates.

  2. Differences in Reef Fish Assemblages between Populated and Remote Reefs Spanning Multiple Archipelagos Across the Central and Western Pacific

    Directory of Open Access Journals (Sweden)

    Ivor D. Williams

    2011-01-01

    Full Text Available Comparable information on the status of natural resources across large geographic and human impact scales provides invaluable context to ecosystem-based management and insights into processes driving differences among areas. Data on fish assemblages at 39 US flag coral reef-areas distributed across the Pacific are presented. Total reef fish biomass varied by more than an order of magnitude: lowest at densely-populated islands and highest on reefs distant from human populations. Remote reefs (<50 people within 100 km averaged ~4 times the biomass of “all fishes” and 15 times the biomass of piscivores compared to reefs near populated areas. Greatest within-archipelagic differences were found in Hawaiian and Mariana Archipelagos, where differences were consistent with, but likely not exclusively driven by, higher fishing pressure around populated areas. Results highlight the importance of the extremely remote reefs now contained within the system of Pacific Marine National Monuments as ecological reference areas.

  3. Aeolian system dynamics derived from thermal infrared data

    Science.gov (United States)

    Scheidt, Stephen Paul

    Thermal infrared (TIR) remote-sensing and field-based observations were used to study aeolian systems, specifically sand transport pathways, dust emission sources and Saharan atmospheric dust. A method was developed for generating seamless and radiometrically accurate mosaics of thermal infrared data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Using a combination of high resolution thermal emission spectroscopy results of sand samples and mosaic satellite data, surface emissivity was derived to map surface composition, which led to improvement in the understanding of sand accumulation in the Gran Desierto of northern Sonora, Mexico. These methods were also used to map sand transport pathways in the Sahara Desert, where the interaction between sand saltation and dust emission sources was explored. The characteristics and dynamics of dust sources were studied at White Sands, NM and in the Sahara Desert. At White Sands, an application was developed for studying the response of dust sources to surface soil moisture based on the relationship between soil moisture, apparent thermal inertia and the erosion potential of dust sources. The dynamics of dust sources and the interaction with sand transport pathways were also studied, focusing on the Bodele Depression of Chad and large dust sources in Mali and Mauritania. A dust detection algorithm was developed using ASTER data, and the spectral emissivity of observed atmospheric dust was related to the dust source area in the Sahara. At the Atmospheric Observatory (IZO) in Tenerife, Spain where direct measurement of the Saharan Air Layer could be made, the cycle of dust events occurring in July 2009 were examined. From the observation tower at the IZO, measurements of emitted longwave atmospheric radiance in the TIR wavelength region were made using a Forward Looking Infrared Radiometer (FLIR) handheld camera. The use of the FLIR to study atmospheric dust from the Saharan is a

  4. Aeolian dunes as ground truth for atmospheric modeling on Mars

    Science.gov (United States)

    Hayward, R.K.; Titus, T.N.; Michaels, T.I.; Fenton, L.K.; Colaprete, A.; Christensen, P.R.

    2009-01-01

    Martian aeolian dunes preserve a record of atmosphere/surface interaction on a variety of scales, serving as ground truth for both Global Climate Models (GCMs) and mesoscale climate models, such as the Mars Regional Atmospheric Modeling System (MRAMS). We hypothesize that the location of dune fields, expressed globally by geographic distribution and locally by dune centroid azimuth (DCA), may record the long-term integration of atmospheric activity across a broad area, preserving GCM-scale atmospheric trends. In contrast, individual dune morphology, as expressed in slipface orientation (SF), may be more sensitive to localized variations in circulation, preserving topographically controlled mesoscale trends. We test this hypothesis by comparing the geographic distribution, DCA, and SF of dunes with output from the Ames Mars GCM and, at a local study site, with output from MRAMS. When compared to the GCM: 1) dunes generally lie adjacent to areas with strongest winds, 2) DCA agrees fairly well with GCM modeled wind directions in smooth-floored craters, and 3) SF does not agree well with GCM modeled wind directions. When compared to MRAMS modeled winds at our study site: 1) DCA generally coincides with the part of the crater where modeled mean winds are weak, and 2) SFs are consistent with some weak, topographically influenced modeled winds. We conclude that: 1) geographic distribution may be valuable as ground truth for GCMs, 2) DCA may be useful as ground truth for both GCM and mesoscale models, and 3) SF may be useful as ground truth for mesoscale models. Copyright 2009 by the American Geophysical Union.

  5. Aeolian Dust and Forest Fire Smoke in Urban Air

    Science.gov (United States)

    Brimblecombe, P.

    2006-12-01

    Particles of aeolian dust and forest fire smoke are now regularly detected in urban air. Although dusts are common on the Asian Pacific Rim and forest fire smoke characteristic of South East Asia they also frequently detected elsewhere. In the past dust was treated as though it was fairly inert and reactions on the surface limited to the neutralizing ability of alkaline minerals. More recent work shows that that dust has a complex organic chemistry. Observations in China found fatty acids from urban areas (oleic acid and linoleic acid from cooking) on dust derived aerosols. The fatty acids and PAHs decreased sharply after dust storms, suggesting a role for dust in removal processes. When silica particles absorb unsaturated compounds they can react with ozone and release compounds such as formaldehyde. Particles from forest fires have a similarly complex chemistry and the acid-alkaline balance may vary depend on the balance of removal rates of alkaline materials (ammonia, potassium carbonate) and inorganic and organic acids. Airborne dust and forest fire soot can contain humic like substances (HULIS) either as primary material or as secondary oxidation products of the surface of soot. This paper will report on the role polluted air masses in the generation humic materials, particularly those that are surface active. These materials of high molecular weight oxygen rich organic compounds, which exhibit a range of properties of importance in aerosols: they can form complexes with metal ions and thus enhance their solubility, photosensitize the oxidation of organic compounds and lower the surface tension of aqueous aerosols. HULIS can be oxidized to form a range of simpler acids such as formic, acetic and oxalic acid. Dust and forest fire smoke particles have a different composition and size range to that of typical urban combustion particles, so it is likely that the health impacts will be different, yet current regulation often does not recognize any significant

  6. Aeolian dune sediment flux heterogeneity in Meridiani Planum, Mars

    Science.gov (United States)

    Chojnacki, Matthew; Urso, Anna; Fenton, Lori K.; Michaels, Timothy I.

    2017-06-01

    It is now known unambiguously that wind-driven bedform activity is occurring on the surface of Mars today, including early detections of active sand dunes in Meridiani Planum's Endeavour crater. Many of these reports are only based on a few sets of observations of relatively isolated bedforms and lack regional context. Here, we investigate aeolian activity across central Meridiani Planum and test the hypothesis that dune sites surrounding Endeavour crater are also active and part of region-wide sediment migration driven by northwesterly winds. All 13 dune fields investigated clearly showed evidence for activity and the majority exhibited dune migration (average rates of 0.6 m/Earth-year). Observations indicate substantial geographic and temporal heterogeneity of dune crest fluxes across the area and per site. Locations with multiple time steps indicate dune sand fluxes can vary by a factor of five, providing evidence for short periods of rapid migration followed by near-stagnation. In contrast, measurements at other sites are nearly identical, indicating that some dunes are in a steady-state as they migrate. The observed sediment transport direction was consistent with a regional northeasterly-to-northwesterly wind regime, revealing more variations than were appreciated from earlier, more localized studies. Craters containing shallow, degraded, flat-floored interiors tended to have dunes with high sediment fluxes/activity, whereas local kilometer-scale topographic obstructions (e.g., central peaks, yardangs) were found to be inversely correlated with dune mobility. Finally, the previous, more limited detections of dune activity in Endeavour crater have been shown to be representative of a broader, region-wide pattern of dune motion.

  7. The Origin of Transverse Aeolian Ridges on Mars

    Science.gov (United States)

    Geissler, P.

    2015-12-01

    Transverse aeolian ridges, or TARs, are found throughout the tropics of Mars and typically appear as rows of bright ripples that are several meters tall and spaced semi-regularly several tens of meters apart. The origin of these features remained mysterious for decades after their discovery in Viking and Mars Global Surveyor images. A new hypothesis (Geissler, 2014, 10.1002-2014JE004633) suggests that TARs might be deposits left behind by dusty turbidity currents in the Martian atmosphere. The hypothesis assumes that the micron-sized dust particles are transported in suspension in turbulent flows, driven both by the winds and by gravity. The dust is concentrated near the surface, much like turbidity currents on Earth. Because of the difference in density, however, the dust clouds behave as a fluid distinct from the clear sky above. In particular, waves can appear at the surface of the dense "fluid" when the flows encounter topographic obstacles along their paths. Such gravity waves travel at speeds that are determined by gravity and the thickness of the flow, much like waves in shallow water on Earth. When the wave propagation speed matches the speed of the flow, stationary waves are produced that persist in fixed locations. The bedforms deposited by such stationary waves are called "antidunes" (Gilbert, 1914, USGS Prof. Paper 86) because, unlike dunes, they can migrate upstream in a supercritical flow. Antidunes are commonly seen in shallow, high energy fluvial deposits on Earth. They are usually destroyed as quickly as they form, and are rarely preserved. The Martian TARs survive because the dust is sticky; TARs are deposited by currents that are much slower than the wind speeds needed to lift the dust again. Subaerial antidunes are much rarer on Earth and less well studied, and so the giant subaerial stationary antidunes of Mars, if that is what the TARs turn out to be, may teach us much about a geological process that is poorly known on our planet.

  8. Structural features of Panarea volcano in the frame of the Aeolian Arc (Italy): Implications for the 2002-2003 unrest

    Science.gov (United States)

    Acocella, Valerio; Neri, Marco; Walter, Thomas R.

    2009-05-01

    Panarea, characterized by gas unrest in 2002-2003, is the volcanic island with the least constrained structure in the eastern-central Aeolian Arc (Italy). Based on structural measurements, we define here its deformation pattern relative to the Arc. The main deformations are subvertical extension fractures (63% of data), normal faults (25%) and dikes (12%). The mean orientation of the extension fractures and faults is ˜N38°E, with a mean opening direction of N135° ± 8°, implying extension with a moderate component of dextral shear. These data, matched with those available for Stromboli volcano (pure opening) and Vulcano, Lipari and Salina volcanoes (predominant dextral motions) along the eastern-central Arc, suggest a progressive westward rotation of the extension direction and an increase in the dextral shear. The dextral shear turns into compression in the western arc. The recent unrest at Panarea, coeval to that of nearby Stromboli, may also be explained by the structural context, as both volcanoes lie along the portion of the Arc subject to extension.

  9. The effects of sorting by aeolian processes on the geochemical characteristics of surface materials: a wind tunnel experiment

    Science.gov (United States)

    Wang, Xunming; Lang, Lili; Hua, Ting; Zhang, Caixia; Li, Hui

    2017-03-01

    The geochemical characteristics of aeolian and surface materials in potential source areas of dust are frequently employed in environmental reconstructions as proxies of past climate and as source tracers of aeolian sediments deposited in downwind areas. However, variations in the geochemical characteristics of these aeolian deposits that result from near-surface winds are currently poorly understood. In this study, we collected surface samples from the Ala Shan Plateau (a major potential dust source area in Central Asia) to determine the influence of aeolian processes on the geochemical characteristics of aeolian transported materials. Correlation analyses show that compared with surface materials, the elements in transported materials (e.g., Cu, As, Pb, Mn, Zn, Al, Ca, Fe, Ga, K, Mg, P, Rb, Co, Cr, Na, Nb, Si, and Zr) were subjected to significant sorting by aeolian processes, and the sorting also varied among different particle size fractions and elements. Variations in wind velocity were significantly correlated with the contents of Cr, Ga, Sr, Ca, Y, Nd, Zr, Nb, Ba, and Al, and with the Zr/Al, Zr/Rb, K/Ca, Sr/Ca, Rb/Sr, and Ca/Al ratios. Given the great variation in the geochemical characteristics of materials transported under different aeolian processes relative to those of the source materials, these results indicate that considerable uncertainty may be introduced to analyses by using surface materials to trace the potential source areas of aeolian deposits that accumulate in downwind areas.

  10. Late-glacial to Holocene aeolian deposition in northeastern Europe - The timing of sedimentation at the Iisaku site (NE Estonia)

    DEFF Research Database (Denmark)

    Kalinska-Nartisa, Edyta; Nartiss, Maris; Thiel, Christine;

    2015-01-01

    The Late-glacial and Holocene aeolian inland dune complex at Iisaku (NE Estonia) has been investigated using an accurate and detailed compilation of the sedimentary properties and chronological framework. The quartz grains forming the dunes are very variable, reflecting aeolian, weathering, and p...

  11. Sedimentary cycles in a Mesoproterozoic aeolian erg-margin succession: Mangabeira Formation, Espinhaço Supergroup, Brazil

    Science.gov (United States)

    Bállico, M. B.; Scherer, C. M. S.; Mountney, N. P.; Souza, E. G.; Reis, A. D.; Raja Gabaglia, G. P.; Magalhães, A. J. C.

    2017-03-01

    Aeolian systems were abundant and widespread in the early Proterozoic, post-2.2 Ga. However, the majority of aeolian successions of such great age are intensely deformed and are preserved only in a fragmentary state meaning that, hitherto, few attempts have been made to apply a sequence stratigraphic approach to determine mechanisms of aeolian construction, accumulation and preservation in such systems. The Mangabeira Formation is a well preserved Mesoproterozoic erg successions covering part of the São Francisco Craton, northeastern Brazil. The lower unit of the Mangabeira Formation ( 500 m thick) comprises aeolian deposits of dune, interdune, and sand-sheet origin, as well as some of waterlain origin. These deposits are organized into vertically stacked depositional cycles, each 6 to 20 m thick, and characterized by aeolian sandsheet and waterlain deposits succeeded by aeolian dune and interdune deposits indicative of a drying-upward trend. Aeolian cross-strata exhibit a mean dip direction to the north. Each of these cycles likely arose in response to climatic oscillation from relatively humid to arid conditions, possibly related to orbital forcing. The lower unit of the Mangabeira Formation comprises up to 14 erg sequences. The accumulation and preservation of each was determined by the relative rate of water-table rise and the availability of sand for aeolian transport, both of which changed through time, resulting in the preservation of a succession of repeated drying-upward cycles.

  12. 10 years of aeolian geomorphology at the EGU: past achievements and future challenges

    Science.gov (United States)

    Baas, Andreas C. W.; Wiggs, Giles F. S.; Claudin, Philippe

    2016-04-01

    On this tenth anniversary of the Aeolian Processes & Landforms session at the EGU the original conveners review and reflect on the recent achievements and expansion in aeolian geomorphological research, focussing on advances in our understanding of sand transport processes, dune development and dynamics, and the mechanisms and scalings involved. This talk will highlight the variety and impact of the dramatic increase in the extent and interest of research on aeolian processes and landforms in the last ten years, including the increasingly strong community presence at international meetings, the diversity and extent of collaborations across subject boundaries, and the application of new measurement technologies and mathematical approaches. We conclude with a forward-looking prospectus of exciting future challenges and open research questions.

  13. High-frequency field observations of aeolian saltation interactions with turbulent boundary layer winds

    CERN Document Server

    Martin, Raleigh L; Chamecki, Marcelo

    2016-01-01

    The wind-blown transport of sand is driven by turbulent winds that fluctuate over a broad range of temporal and spatial scales. Increasingly sophisticated models and wind tunnel experiments have attempted to capture these dynamics of aeolian saltation, yet model predictions often diverge substantially from field observations. To help fill this knowledge gap, we collected comprehensive high-frequency field measurements to characterize the dynamics of aeolian saltation under natural conditions. Here, we provide detailed description of our field deployments, including information about sites, instruments, and data processing methods. We then demonstrate how our field measurements can help to improve understanding of the mechanics of aeolian processes. We also describe the limitations of our measurement techniques and the needs for future work.

  14. Influence of grain size, shape and compaction on georadar waves: example of an Aeolian dune

    CERN Document Server

    Guillemoteau, Julien; Dujardin, Jean-Rémi; 10.1111/j.1365-246X.2012.05577.x

    2012-01-01

    Many Ground Penetrating Radar (GPR) profiles acquired in dry aeolian environment have shown good reflectivity inside present-day dunes. We show that the origin of this reflectivity is related to changes in grain size distribution, packing and/or grain shape in a sandy material. We integrate these three parameters into analytical models for bulk permittivity in order to predict the reflections and the velocity of GPR waves. We consider two GPR cross-sections acquired over Aeolian dunes in the Chadian desert. The 2D migration of GPR data suggests that dunes contain different kinds of bounding surfaces. We discuss and model three kinds of reflections using reasonable geological hypothesis about Aeolian sedimentation processes. The propagation and the reflection of radar waves are calculated using the 1D wavelet modelling method in spectral domain. The results of the forward modelling are in good accordance with real observed data.

  15. Faroe Islands

    DEFF Research Database (Denmark)

    Christoffersen, Lisbet

    2015-01-01

    An update introduction including recent legislative changes on the Folkchurch of the Faroe Islands......An update introduction including recent legislative changes on the Folkchurch of the Faroe Islands...

  16. Radiocarbon evidence for the presence of mice on Madeira Island (North Atlantic) one millennium ago.

    Science.gov (United States)

    Rando, Juan Carlos; Pieper, Harald; Alcover, Josep Antoni

    2014-04-07

    Owing to the catastrophic extinction events that occurred following the Holocene arrival of alien species, extant oceanic island biotas are a mixture of recently incorporated alien fauna and remnants of the original fauna. Knowledge of the Late Quaternary pristine island faunas and a reliable chronology of the earliest presence of alien species on each archipelago are critical in understanding the magnitude and tempo of Quaternary island extinctions. Until now, two successive waves of human arrivals have been identified in the North Atlantic Macaronesian archipelagos (Azores, Madeira, Selvagens, Canary and Cape Verde Islands): 'aboriginal', which is limited to the Canary Islands around two millennia ago, and 'colonial', from the fourteenth century onwards. New surveys in Ponta de São Lourenço (Madeira Island) have allowed us to obtain and date ancient bones of mice. The date obtained (1033 ± 28 BP) documents the earliest evidence for the presence of mice on the island. This date extends the time frame in which the most significant ecological changes occurred on the island. It also suggests that humans could have reached Madeira before 1036 cal AD, around four centuries before Portugal officially took possession of the island.

  17. Active ageing as lifestyle on Croatian islands

    Directory of Open Access Journals (Sweden)

    Klempić-Bogadi Sanja

    2014-01-01

    Full Text Available The main feature of Croatian islands, in addition to their beautiful nature, is the fact that they are demographically and sociologically one of the most threatened areas affected by ageing. The ageing of the island population is the result of a long-term depopulation caused by the continuous emigration of the younger working-active population over the past hundred years, but also by the retirement return migration in the last thirty years. The most critical situation is on small islands where the majority of population is aged over 60 and this has a significant impact on all aspects of island life. The research conducted on small islands in the Šibenik archipelago in 2011 has shown that older people live alone, with no significant health problems limiting their daily activities, in their own households (homes, on modest pensions, and many of them supplement their income through agriculture. They very often financially help their children, who live mostly in nearby mainland cities. The necessity of self-reliance, due to the lack of younger generations, forces the inhabitants of Croatian island to lead an active life until their old age. Although they are no longer actively employed, they still continue to contribute significantly to the family and society through their involvement in various community activities.

  18. Rational design equations for the Aeolian vibration of overhead power lines

    Energy Technology Data Exchange (ETDEWEB)

    Lu, M.L.; Chopra, N. [BC Hydro, Burnaby, BC (Canada)

    2008-07-01

    Aeolian vibration must be considered when designing overhead power transmission lines because of its potential risk of causing fatigue failure to the conductor, hardware, and tower members. Aeolian vibration is caused by the alternate shedding of Karman vortices from the top and bottom of the line's conductor when the conductor is exposed to a side wind. This paper presented a novel approach to analytically predict the vortex-induced vibration (i.e. Aeolian vibration) of an overhead power line's single conductor due to wind. The paper described the derivation of an analytical solution to the basic problem of the Aeolian vibration of a conductor span with equivalent supports on both ends by using the energy balance principle as well as the semi-empirical equations for the wind power input and the self damping of a conductor. The paper noted that a wind's turbulence effect may also be taken into account by using a previously found analytical solution. Simple, pragmatic design equations were established for undamped conductor spans by curve-fitting the numerical data from analytical solutions. It was concluded that the complicated problem of Aeolian vibration of a single conductor without damper or with multiple dampers could be easily solved by using the analytical solutions developed in this paper and that simple, yet rational design equations have been established for the Aeolian vibration of undamped conductor spans to bridge the gap between the apparently complicated theory and the often overly simplified actual design practice. 13 refs., 1 tab., 4 figs.

  19. Our evolving understanding of aeolian bedforms, based on observation of dunes on different worlds

    Science.gov (United States)

    Diniega, Serina; Kreslavsky, Mikhail; Radebaugh, Jani; Silvestro, Simone; Telfer, Matt; Tirsch, Daniela

    2017-06-01

    Dunes, dune fields, and ripples are unique and useful records of the interaction between wind and granular materials - finding such features on a planetary surface immediately suggests certain information about climate and surface conditions (at least during the dunes' formation and evolution). Additionally, studies of dune characteristics under non-Earth conditions allow for ;tests; of aeolian process models based primarily on observations of terrestrial features and dynamics, and refinement of the models to include consideration of a wider range of environmental and planetary conditions. To-date, the planetary aeolian community has found and studied dune fields on Mars, Venus, and the Saturnian moon Titan. Additionally, we have observed candidate ;aeolian bedforms; on Comet 67P/Churyumov-Gerasimenko, the Jovian moon Io, and - most recently - Pluto. In this paper, we hypothesize that the progression of investigations of aeolian bedforms and processes on a particular planeta