WorldWideScience

Sample records for sand island ocean

  1. Benthic faunal sampling adjacent to the Sand Island ocean outfall, Oahu, Hawaii, 1986-2010 (NODC Accession 9900088)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic fauna in the vicinity of the Sand Island ocean outfall were sampled from 1986-2010. To assess the environmental quality, sediment grain size and sediment...

  2. Community structure of fish and macrobenthos at selected sites fronting Sand Island, Oahu, Hawaii in relation to the Sand Island Deep Ocean Sewage Outfall, 1990 - 1998 (NODC Accession 0000177)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report provides the results of nine years of an annual quantitative monitoring of shallow marine communities inshore of the Sand Island Ocean Outfall, Oahu,...

  3. Sediment monitoring and benthic faunal sampling adjacent to the Sand Island ocean outfall, Oahu, Hawaii, 1986-2010 (NODC Accession 9900088)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic fauna and sediment in the vicinity of the Sand Island ocean outfall were sampled from 1986-2010. To assess the environmental quality, sediment grain size and...

  4. 78 FR 27124 - Pacific Ocean Off the Kekaha Range Facility at Barking Sands, Island of Kauai, Hawaii; Danger Zone

    Science.gov (United States)

    2013-05-09

    ... Barking Sands, Island of Kauai, Hawaii; Danger Zone AGENCY: U.S. Army Corps of Engineers, DoD. ACTION... amend its regulations to establish a new danger zone in waters of the Pacific Ocean off the Kekaha Range... INFORMATION: Executive Summary The purpose of this regulatory action is to establish a new danger zone...

  5. Reef community structure, Sand Island, Oahu HI, (NODC Accession 0000177)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These reports provide the results of nine years (1990-98) of an annual quantitative monitoring of shallow marine communities inshore of the Sand Island Ocean...

  6. Provenance analysis of heavy minerals in beach sands (Falkland Islands/Islas Malvinas) - A view to mineral deposits and the geodynamics of the South Atlantic Ocean

    Science.gov (United States)

    Dill, Harald G.; Skoda, Radek

    2017-10-01

    Beach sands are ideal traps to collect heavy minerals (HM) from different geodynamic settings and mineral deposits. The coastal sediments contain a mixture of HM derived from the submarine shelf and from source rocks in the hinterland. This is true in a transgressive periglacial regime, where drowned valleys and estuaries are instrumental in draining HM to the arenaceous beach sediments from more distal basement lithologies. A scenario like this can be found in the Falkland Islands/Islas Malvinas. The site under study is the missing link between South Africa and South America, the splitting-apart of which is mirrored by the HM distribution predominantly concentrated in the backshore and dune belt along the coast. The HM are subdivided into three HM associations reflecting the geodynamic evolution of the South Atlantic Ocean and of some of the prominent mineral deposits on the Gondwana Continent: (1) Gondwana cratons and Proterozoic orogens, with Cr and BIF deposits (rutile, zircon, ilmenite, tourmaline, garnet, Cr spinel), (2) rift-related and break-apart magmatic lithologies with mantle-derived pipe rocks such as kimberlites (zircon, pyroxene, spinel, Mg ilmenite), (3) Cordillera-type lithologies with polymetallic stratabound deposits (tourmaline, amphibole, chlorite, REE phosphates). The variation of the major HM from the stable craton (Kalahari-Kaapvaal Craton) in the East to the mobile fold belt (Andes) in the West follows the order of stability of HM. In addition to these 3 geodynamic HM groups, sporadic occurrences of HM originating from alteration (leucoxene, chlorite s.s.s. (= solid solution series)) are part of armored relics such as ;nigrine; which on transport disintegrated and thereby released these HM. The major ultrastable and stable HM zircon, rutile, tourmaline s.s.s., spinel s.s.s., and garnet s.s.s. are displayed in a synoptical x-y plot showing the mantle and crustal trends of fractionation and formation of cumulates by means of particular

  7. Back-Island and Open-Ocean Shorelines, and Sand Areas of the Undeveloped Areas of New Jersey Barrier Islands, March 9, 1991, to July 30, 2013

    Science.gov (United States)

    Guy, Kristy K.

    2015-11-09

    Assessing the physical change to shorelines and wetlands is critical for determining the resiliency of wetland systems that protect adjacent habitat and communities. The wetland and back-barrier shorelines of the New Jersey barrier islands were changed by wave action and storm surge from Hurricane Sandy in 2012. The U.S. Geological Survey Coastal and Marine Geology Program is assessing the impact of Hurricane Sandy to understand its historical context and the vulnerability of wetland systems. These assessments require data that document physical changes over time, such as maps, aerial photographs, satellite imagery, and lidar elevation data.

  8. LEARNING ABOUT THE OCEANS FROM SAND

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    As a young geophysicist in the 1980s, Rob Holman attended a conference in San Francisco that included a field trip to a beach. Dr Holman, who grew up inland, stared at the ocean, assessing the strengths of the waves. But when he looked around, everyone else was studying the sand.

  9. Developing a Sand Management Plan for Galveston Island

    Science.gov (United States)

    2015-10-16

    US Army Corps of Engineers BUILDING STRONG® Developing a Sand Management Plan for Galveston Island Ashley E. Frey, P. E. Research Civil...GenCade Alternatives • Sand Management Alternatives and Plan • Beach Nourishment Project 2 Innovative solutions for a safer, better world...BUILDING STRONG® Problem Statement/Approach Recommend a long-term plan of actions to better manage sands on Galveston Island Initial Tasks

  10. Synthesizing knowledge of ocean islands

    Science.gov (United States)

    Jefferson, Anne J.; Lees, Jonathan M.; McClinton, Tim

    2011-11-01

    AGU Chapman Conference on the Galápagos as a Laboratory for the Earth Sciences; Puerto Ayora, Galápagos, Ecuador, 25-30 July 2011 An inspiration for Darwin's theory of evolution, the Galápagos Islands and surrounding waters are a natural laboratory for a wide range of Earth science topics. The Galápagos are perfectly situated for geophysical and geochemical investigations of deep-Earth processes at a hot spot, and proximity to a spreading center allows exploration of hot spot-ridge interactions. Several highly active volcanoes show rapid deformation facilitating investigation of melt transport paths and volcanic structure. The islands exhibit a range of ages, eruptive styles, and climatic zones that allow analysis of hydrogeologic and geomorphic processes. The Galápagos Islands are a World Heritage Site and are an ideal setting for developing an integrated biological and geological understanding of ocean island evolution.

  11. Assessment of Enterococcus Levels in Recreational Beach Sand Along the Rhode Island Coast.

    Science.gov (United States)

    Coakley, Eugenie; Parris, Amie L; Wyman, Al; Latowsky, Gretchen

    2016-04-01

    Recent studies have shown that coastal beach sand as well as coastal ocean water can be contaminated with fecal indicator Enterococcus bacteria (ENT). A study of sand ENT concentrations over a four-week period at 12 Rhode Island beaches was conducted during the summer of 2009. While average contamination was low relative to water quality standards, every beach had at least one day with very high sand ENT readings. On 10 of the 12 beaches, a statistically significant gradient occurred in geometric mean ENT concentrations among tidal zones, with dry (supratidal, or above high tide mark) sand having the highest level, followed by wet (intratidal, or below high tide mark) and underwater sand. Beaches with higher wave action had significantly lower ENT levels in wet and underwater sand compared to beaches with lower wave action.

  12. A quantitative approach to monitoring new sand cay migration in Nansha Islands

    Institute of Scientific and Technical Information of China (English)

    ZHU Haitian; JIANG Xingwei; MENG Xuelian; FENG Qian; CUI Songxue; LIANG Chao

    2016-01-01

    Sand cay is a special kind of islet formed by coral detritus and bioclast, which is common in Nansha Islands of China. Some sand cays play an important role in ocean strategy and economy, but surprisingly we know little about them, especially those recently formed sand cays. In this research, we monitor migration of a new sand cay in Nanxun Jiao (Gaven Reef) using a series of QuickBird and WorldView-2 satellite images between June 2006 and August 2013. We conduct a regression between migration distance and wind observational data to examine the migration patterns of the new sand cay. The migration distance is calculated based on the sand cay locations extracted based on Normalized Difference Water Index (NDWI). The wind observational data downloaded from NOAA are reformed into four wind direction vectors. Based on the results of regression, we concluded that the migration of the new sand cay on Nanxun Jiao was significantly associated with the east, west and north wind. East wind was the main influence factor of the migration; its impact strength was almost twice as the west and north wind. The south wind has little effect on the migration of the sand cay, which is partly blocked by the artificial structure in the south.

  13. Galveston Island, Texas, Sand Management Strategies

    Science.gov (United States)

    2016-07-01

    68 Figure 28. Jetty segment used for computation of aeolian sand transport. Background photograph 22 May 2012...113 Figure 68 . Total shoreline change after 50 years for 500,000 yd3 placed every 2 years in different locations...The berm at Ft. Myers, FL, was constructed with dredged material from Matanzas Pass. The dredged material contained greater than 10% fines, which

  14. Sand Resources and Geological Character of Long Island Sound.

    Science.gov (United States)

    1981-05-01

    Ashraf (1973a, 1973b), Coch (1974), and Williams (1976) identified deeply buried stream channels which are pre-Pleistocene but acted as conduits for...Migration of Sand Waves in a Large Estuary, Long Island Sound," Marine Geology, Vol. 24, 1977, pp. 185-199. COCH , N., "Morphology and Sediment

  15. 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.

  16. Source, route and effect of Asian sand dust on environment and the oceans

    Institute of Scientific and Technical Information of China (English)

    Kai Zhang; Fahe Chai; Renjian Zhang; Zhigang Xue

    2010-01-01

    We summarize in this overview achievements in current research frontiers in Asian sand dust with emphasis on the method for sand dust research,the sources of sand dust aerosols,emission of sand dust,mechanism of sand dust weather,chemical transformation during transport,and influences on climatic environment and oceans.Our main results show that most of Asian sand dust comes from Mongolia,the Gobi Desert,arid and semiarid desert areas in northwest China,which is divided into initial sources and enhanced sources.Half of the global production of dust originates from Asian dust source regions.Asian dust weather is so immense that it can cover a 5-7-day journey from the sources to the Korean Peninsula,Japan Islands,and the Pacific Ocean to even impact North America.Asian dust weather plays an active role in the biogeochemical cycles of trace elements in the mid-latitude Northern Hemisphere.

  17. 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.

  18. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

    Triantis, K.A.; Borges, Paulo A. V.; Ladle, R.J.;

    2010-01-01

    the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species-area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands...

  19. The Rhode Island Ocean Special Area Management Plan (Ocean SAMP)

    Energy Technology Data Exchange (ETDEWEB)

    Fugate, Grover J. [Univ. of Rhode Island, Kingston, RI (United States)

    2012-06-01

    In 2010, the University of Rhode Island (URI) secured $2,000,000 from the Rhode Island Office of Energy Resources (OER) to support research studies for the identification of preferred sites for offshore renewable energy development in Rhode Island’s offshore waters. This research will provide the Rhode Island Coastal Resources Management Council (CRMC) with sound technical information to assist in the siting of wind turbines in Rhode Island’s offshore waters. CRMC is the state agency with jurisdiction over development, preservation and restoration of Rhode Island’s coasts out to the three-mile limit, and is the state’s authority for federal consistency. With technical support from URI, CRMC is currently leading the implementation of the Rhode Island Ocean Special Area Management Plan (Ocean SAMP) with the purpose of developing policies and standards to guide the development of offshore renewable energy. The justification behind renewable energy development in Rhode Island includes diversifying the energy sources supplying electricity consumed in the state, stabilizing long-term energy prices, enhancing environmental quality – including the reduction of air pollutants and greenhouse gas emissions – reducing the state’s reliance on fossil fuels, and creating jobs in Rhode Island in the renewable energy sector.

  20. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

    Triantis, Kostas A.; Borges, Paulo A. V.; Ladle, Richard J.

    2010-01-01

    Habitat destruction is the leading cause of species extinctions. However, there is typically a time-lag between the reduction in habitat area and the eventual disappearance of the remnant populations. These "surviving but ultimately doomed" species represent an extinction debt. Calculating...... the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species-area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands...... in the last 45 yr, despite the extensive sampling effort, offer support to the predictions made. We argue that immediate action to restore and expand native forest habitat is required to avert the loss of numerous endemic species in the near future...

  1. Gentle Africanized bees on an oceanic island.

    Science.gov (United States)

    Rivera-Marchand, Bert; Oskay, Devrim; Giray, Tugrul

    2012-11-01

    Oceanic islands have reduced resources and natural enemies and potentially affect life history traits of arriving organisms. Among the most spectacular invasions in the Western hemisphere is that of the Africanized honeybee. We hypothesized that in the oceanic island Puerto Rico, Africanized bees will exhibit differences from the mainland population such as for defensiveness and other linked traits. We evaluated the extent of Africanization through three typical Africanized traits: wing size, defensive behavior, and resistance to Varroa destructor mites. All sampled colonies were Africanized by maternal descent, with over 65% presence of European alleles at the S-3 nuclear locus. In two assays evaluating defense, Puerto Rican bees showed low defensiveness similar to European bees. In morphology and resistance to mites, Africanized bees from Puerto Rico are similar to other Africanized bees. In behavioral assays on mechanisms of resistance to Varroa, we directly observed that Puerto Rican Africanized bees groomed-off and bit the mites as been observed in other studies. In no other location, Africanized bees have reduced defensiveness while retaining typical traits such as wing size and mite resistance. This mosaic of traits that has resulted during the invasion of an oceanic island has implications for behavior, evolution, and agriculture.

  2. Parrotfish erosion underpins reef growth, sand talus development and island building in the Maldives

    Science.gov (United States)

    Morgan, Kyle M.; Kench, Paul S.

    2016-07-01

    Parrotfish play a key functional role on coral reefs as external bioerosion agents and produce large quantities of carbonate sediment as a by-product of grazing on reef surfaces. Parrotfish are therefore an important potential source of sediment for island construction and maintenance within atoll reef environments, particularly under future scenarios of sea level rise and island morphological change. Here, we present the first field-based estimates of excavating parrotfish erosion (Chlorurus sordidus and Chlorurus strongylocephalus) within the Indian Ocean and quantify the contribution of parrotfish to the carbonate and sediment budgets of an atoll interior reef platform in the Maldives. We note that parrotfish erosion rates are high (6.3 kg m- 2 y- 1), generating large amounts of new coral-based sediment (2.6 kg m- 2 y- 1) that has a comparable grain size distribution to island deposits. Mean erosion rates by individual C. strongylocephalus (405 kg individual y- 1) were higher than C. sordidus (55 kg individual y- 1), but their contribution to erosion per unit area of reef was less due to a lower relative biomass (C. strongylocephalus: 1.3 kg m- 2 y- 1; C. sordidus: 5.0 kg m- 2 y- 1). Parrotfish also facilitate sediment export from reefs (0.7 kg m- 2 y- 1), which contributes extensively to the development of the sand talus on the fore-reef slope and to the evolution of the wider atoll basin. Our results provide strong evidence that parrotfish erosion (and sediment generation) underpins island morphology on Maldivian reefs and highlight the importance of larger parrotfish as producers of island-grade sediment. Ecological processes must therefore be considered within future coastal management strategies for enhancing island stability.

  3. Oceanic heat sources to Pine Island Bay

    Science.gov (United States)

    Mazloff, M. R.; Gilroy, A. R.; Gille, S. T.; Subramanian, A. C.

    2012-12-01

    The rapid melting of Pine Island Glacier, West Antarctica has been attributed to increased basal melting of its grounded ice-shelf. Recent work suggests that an increased ocean heat supply to Pine Island Bay (PIB) is responsible for this increased melting. There is no consensus, however, on the origin of this increased ocean heat. We use a 2008-2010 state estimate of the Southern Ocean to diagnose the heat budget on the PIB continental shelf. In times of minimal sea-ice coverage, air-sea fluxes dominate the budget. Sea-ice is present over much of the year, however, and on average advection and parameterized small-scale mixing are equally important. The average air-sea fluxes and small scale mixing both act to cool the continental shelf waters, while advection by the large-scale circulation tends to warm these waters. The warmest waters are found on the eastern PIB continental shelf where bathymetric features cause increased advective fluxes and mixing. The average circulation along the PIB continental shelf is eastward consisting of approximately 1 Sv along shelf flow augmented by 1 Sv of across shelf flow to be balanced by a 2 Sv outflow along the eastern PIB shelf. Numerical simulations of passive tracer releases reveal the advective pathways of these waters that reach the continental shelf.

  4. Regional Ocean Modeling System (ROMS): Main Hawaiian Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 7-day, 3-hourly forecast for the region surrounding the main Hawaiian islands at approximately 4-km resolution. While...

  5. Regional Ocean Modeling System (ROMS): Main Hawaiian Islands: Data Assimilating

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 3-day, 3-hourly data assimilating hindcast for the region surrounding the main Hawaiian islands at approximately 4-km...

  6. The shallow stratigraphy and sand resources offshore from Cat Island, Mississippi

    Science.gov (United States)

    Kindinger, Jack G.; Miselis, Jennifer L.; Buster, Noreen A.

    2014-01-01

    In collaboration with the U.S. Army Corps of Engineers, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center collected over 487 line kilometers (> 300 miles) of high-resolution geophysical data around Cat Island, Mississippi, to improve understanding of the island's geologic evolution and identify potential sand resources for coastal restoration. In addition, 40 vibracores were collected on and around the island, generating more than 350 samples for grain-size analysis. The results indicate that the geologic evolution of Cat Island has been influenced by deltaic, lagoonal/estuarine, tidal, and oceanographic processes, resulting in a stratigraphic record that is quite complex. The region north of the island is dominated by lagoonal/estuarine deposition, whereas the region south of the island is dominated by deltaic and tidal deposition. In general, the veneer of modern sediment surrounding the island is composed of newly deposited sediment and highly reworked relict sediments. The region east of the island shows the interplay of antecedent barrier-island change with delta development despite a significant ravinement of sediments. The data show from little to no modern sediment east of the island, exposing relict sediments at the seafloor. Finally, the data reveal four subaqueous sand units around the island. Two of the units are northwest of the modern island and one is southwest. Given the dominant, westward, longshore transport along the Mississippi and Alabama barrier islands, the geographic location of these three units suggests that they do not contribute to the modern sediment budget of Cat Island. The last unit is directly east of the island and represents the antecedent island platform that has supplied sand over geologic time for creation of the spits that form the eastern shoreline. Because of its location east of the island, the antecedent island unit may still supply sediment to the island today.

  7. Silica Sand Identification using ALOS PALSAR Full Polarimetry on The Northern Coastline of Rupat Island, Indonesia

    Directory of Open Access Journals (Sweden)

    Husnul Kausarian

    2016-10-01

    Full Text Available Silica sand is one of the minerals which relatively abundant in Indonesia. One of the areas with abundant of silica sand distribution is the northern coastline of Rupat Island, Bengkalis district, Riau province, Indonesia. The distribution of silica sand in this island identified only on the northern coastline in this island. Some selected sample of silica sand was measured to get the percentage of silica sand mineral’s content using X-Ray Fluorescence (XRF. Two adjacent scenes of ALOS PALSAR full-polarimetry were used. The physical properties of silica sand sample such as dielectric constant were measured using dielectric probe kit in the frequency range from 0.3 to 3.0 GHz and used for calculating the backscattering coefficient and the difference characteristics of silica sand with another object. Freeman-Durdeen and Yamaguchi techniques were used to get the scattering decomposition of physical scattering from the incoherent object model based. Surface scattering is the clearest of Scattering decomposition to show silica sand identification compares with other decompositions. From surface scattering, the backscattering coefficient value of silica sand was calculated starting from -59 dB until -52 dB. These values were given by the surface roughness condition, where the roughness is slightly rough planar. The flat condition supported by the grain size of silica sand particles that have almost the same size and shape, that were conducted by using microscopic photograph testing.

  8. Pollination, biogeography and phylogeny of oceanic island bellflowers (Campanulaceae)

    DEFF Research Database (Denmark)

    Olesen, Jens Mogens; Alarcón, M.; Ehlers, Bodil

    2012-01-01

    relatives C. eminii and C. abyssinica. We asked to what extent related species converge in their floral biology and pollination in related habitats, i.e. oceanic islands. Study islands were the Azores, Madeira, Canary Islands, Cape Verde, Mauritius, and Réunion. Information about phylogenetic relationships...

  9. 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”.

  10. Sand dynamic in the Mekong River channel and export to the coastal ocean

    Science.gov (United States)

    Stephens, J. D.; Allison, M. A.; Di Leonardo, D. R.; Weathers, H. D.; Ogston, A. S.; McLachlan, R. L.; Xing, F.; Meselhe, E. A.

    2017-09-01

    Two field campaigns were conducted in the tidal and estuarine reach of the Sông Hậu distributary of the Mekong River to explore the dynamics of sand transport and export to the coastal ocean. This study examines variations in suspended sand concentration and net flux of suspended and bedload sand with respect to changes in discharge between the October 2014 high discharge and March 2015 low discharge season. Isokinetic measurements of suspended sand were used to calibrate a larger dataset of LISST profiles to report suspended sand mass concentrations. During the high discharge season, ebb and flood currents are a primary control on suspended sand concentrations. Ebb tidal flows are more capable of sand transport than flooding flows, due to river discharge augmenting tidal currents. Sand in suspension is primarily derived locally from bed material sand. Bedform transport estimates were limited, but suggest that bedload sand transport is less than 10% of net suspended sand flux. Very low concentrations of suspended sand sediment are found during the low discharge season. These low concentrations are likely caused by (1) a reduction in maximum ebb tide shear stresses associated with less freshwater input, and (2) mud mantling in the bed associated with upstream migration of estuarine circulation, that inhibits local sourcing (resuspension) of bed sand. Results of the observational study were used to calibrate a numerical model of annual sand flux to the ocean from all distributaries of the Mekong River. Annual sand export is estimated at 6.5 ± 1.6 Mt yr-1. The Định An subdistributary accounts for 32% of this total while the smaller Trần Đề subdistributary accounts for only 9%.

  11. Terrestrial and coastal landscape evolution on tropical oceanic islands

    NARCIS (Netherlands)

    Viles, H.A.; Spencer, T.

    2011-01-01

    Tropical oceanic islands owe their origin to volcanic eruptions, their location to plate tectonics, and their morphology to the interplay over time between a range of constructional and erosional processes. A broad distinction can be made between high volcanic islands, with summits up to 4,000 m, an

  12. Helium isotopic systematics of oceanic islands and mantle heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, M.D.; Jenkins, W.J. (Woods Hole Oceanographic Institution, MA (USA)); Hart, S.R. (Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Earth and Planetary Sciences)

    1982-05-06

    The results of helium isotopic analyses in basaltic phenocrysts from the islands of Gough and Tristan da Cunha are reported which seem to indicate that the mantle beneath these islands are not primitive or undepleted relative to mid-ocean ridge basalt (MORB). New analyses from Loihi Seamount are also reported which do indicate a more primitive source. When these data are combined with values for MORBs previously obtained and plotted with respect to /sup 87/Sr//sup 86/Sr, the observed trends offer insight into the different source regions for oceanic island basalts and the nature of mantle heterogeneity.

  13. Oceanic Platform of the Canary Islands: an ocean testbed for ocean energy converters

    Science.gov (United States)

    González, Javier; Hernández-Brito, Joaquín.; Llinás, Octavio

    2010-05-01

    The Oceanic Platform of the Canary Islands (PLOCAN) is a Governmental Consortium aimed to build and operate an off-shore infrastructure to facilitate the deep sea research and speed up the technology associated. This Consortium is overseen by the Spanish Ministry of Science and Innovation and the Canarian Agency for Research and Innovation. The infrastructure consists of an oceanic platform located in an area with depths between 50-100 meters, close to the continental slope and four kilometers off the coast of Gran Canaria, in the archipelago of the Canary Islands. The process of construction will start during the first months of 2010 and is expected to be finished in mid-year 2011. PLOCAN serves five strategic lines: an integral observatory able to explore from the deep ocean to the atmosphere, an ocean technology testbed, a base for underwater vehicles, an innovation platform and a highly specialized training centre. Ocean energy is a suitable source to contribute the limited mix-energy conformed in the archipelago of the Canary Islands with a total population around 2 million people unequally distributed in seven islands. Islands of Gran Canaria and Tenerife support the 80% of the total population with 800.000 people each. PLOCAN will contribute to develop the ocean energy sector establishing a marine testbed allowing prototypes testing at sea under a meticulous monitoring network provided by the integral observatory, generating valuable information to developers. Reducing costs throughout an integral project management is an essential objective to be reach, providing services such as transportation, customs and administrative permits. Ocean surface for testing activities is around 8 km2 with a depth going from 50 to 100 meters, 4km off the coast. Selected areas for testing have off-shore wind power conditions around 500-600 W/m2 and wave power conditions around 6 kW/m in the East coast and 10 kW/m in the North coast. Marine currents in the Canary Islands are

  14. 2004 INDIAN OCEAN TSUNAMI ON THE MALDIVES ISLANDS: INITIAL OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    Barbara H. Keating

    2005-01-01

    Full Text Available Post-tsunami field surveys of the Maldives Islands where carried out to document the effects of the tsunami inundation. The study area was situated in the islands of South Male Atoll that were some of the most heavily damaged islands of the Maldive Islands. The tsunami damaged the natural environment, vegetation, man-made structures, and residents. The maximum tsunami wave height was 3-4 m. This level of inundation exceeded the height of most residents. The wave height was greatest on the eastern rim of the South Male Atoll (closest to the tsunami source and these islands were completely flooded. The islands within the interior of the atoll saw the lowest wave heights, and these were only marginally flooded.Surveys of flood lines left on the exterior and interior of structures were measured but proved to be substantially less than that reported by survivors. It appears that the highest inundation was not preserved as flood lines. We suggest that the turbulence associated with the tsunami inundation erased the highest lines or that they did not form due to an absence of debris and organic compounds that acted as adhesion during the initial flooding.Significant erosion was documented. Deposition took place in the form of sand sheets while only desultory deposition of coral clasts in marginal areas was found. Seasonal erosion, and storms are likely to remove most or all of the traces of the tsunami within these islands.

  15. Pollination, biogeography and phylogeny of oceanic island bellflowers (Campanulaceae)

    DEFF Research Database (Denmark)

    Olesen, Jens Mogens; Alarcón, M.; Ehlers, Bodil

    2012-01-01

    We studied the pollination biology of nine island Campanulaceae species: Azorina vidalii, Musschia aurea, M. wollastonii, Canarina canariensis, Campanula jacobaea, Nesocodon mauritianus, and three species of Heterochaenia. In addition, we compared C. canariensis to its two African mainland...... relatives C. eminii and C. abyssinica. We asked to what extent related species converge in their floral biology and pollination in related habitats, i.e. oceanic islands. Study islands were the Azores, Madeira, Canary Islands, Cape Verde, Mauritius, and Réunion. Information about phylogenetic relationships...... of these species and their relatives were gathered from atpB, matK, rbcL and trnL-F regions, building the most complete phylogeny of Campanulaceae to date. Six of the island bellflower species were bird-pollinated and two (A. vidalii and M. aurea) were lizard-pollinated. Insects also visited some of the species...

  16. Seismic structure of the lithosphere beneath the ocean islands near the mid-oceanic ridges

    Science.gov (United States)

    Haldar, C.; Kumar, P.; Kumar, M. Ravi

    2013-10-01

    Deciphering the seismic character of the young lithosphere near the mid-oceanic ridges (MOR) is a challenging endeavor. In this study, we determine the seismic structure of the oceanic plate near the MORs, using the P-to-s conversions isolated from good quality data recorded at 5 broadband seismological stations situated on the ocean Islands in their vicinity. Estimates of the crustal and lithospheric thickness values from waveform modeling of the P receiver function stacks reveal that the crustal thickness varies between 6 and 8 km with the corresponding depths to the lithosphere asthenosphere boundary (LAB) varying between 43 and 68 km. However, the depth to the LAB at Macquire Island is intriguing in view of the observation of a thick (~ 87 km) lithosphere beneath a relatively young crust. At three other stations i.e., Ascension Island, Sao Jorge and Easter Island, we find evidence for an additional deeper low velocity layer probably related to the presence of a hotspot.

  17. Insular endemism in Recent Southern Ocean benthic Ostracoda from Marion Island: palaeozoogeographical and evolutionary implications

    DEFF Research Database (Denmark)

    Dingle, R.V.

    2002-01-01

    benthic ostracods, subantarctic, endemism, insularity, Marion Island, Southern Ocean, colonisation, quaternary, eyes, ocular-rejuvenation, dormant genes, evolution......benthic ostracods, subantarctic, endemism, insularity, Marion Island, Southern Ocean, colonisation, quaternary, eyes, ocular-rejuvenation, dormant genes, evolution...

  18. Landscape Evolution of the Oil Spill Mitigation Sand Berm in the Chandeleur Islands, Louisiana

    Science.gov (United States)

    2016-09-01

    Mercator (UTM) Zone 16 and the North Ameri- can Vertical Datum (NAVD) of 1988 (using the GEOID09 model) coordi- nate systems . The 2011 LiDAR data were...cooperative workplan with BP) derived the 2010 SAV data from 1 ft resolution visible and near - infrared imagery collected by Aerometric in October 2010...and near -term impacts to the island system . The sand berm provided short-term benefits, primarily through the intro- duction of sediment into a

  19. Mesophilic Actinomycetes in the natural and reconstructed sand dune vegetation zones of Fraser Island, Australia.

    Science.gov (United States)

    Kurtböke, D I; Neller, R J; Bellgard, S E

    2007-08-01

    The natural coastal habitat of Fraser Island located in the State of Queensland, Australia, has been disturbed in the past for mining of the mineral sand ilmenite. Currently, there is no information available on whether these past mining disturbances have affected the distribution, diversity, and survival of beneficial soil microorganisms in the sand dunes of the island. This in turn could deleteriously affect the success of the natural regeneration, plant growth, and establishment on the sand dunes. To support ongoing restoration efforts at sites like these mesophilic actinomycetes were isolated using conventional techniques, with particular emphasis on the taxa previously reported to produce plant-growth-promoting substances and providing support to mycorrhizal fungi, were studied at disturbed sites and compared with natural sites. In the natural sites, foredunes contained higher densities of micromonosporae replaced by increasing numbers of streptomycete species in the successional dune and finally leading to complex actinomycete communities in the mature hind dunes. Whereas in the disturbed zones affected by previous mining activities, which are currently being rehabilitated, no culturable actinomycete communities were detected. These findings suggest that the paucity of beneficial microflora in the rehabilitated sand dunes may be limiting the successful colonization by pioneer plant species. Failure to establish a cover of plant species would result in the mature hind dune plants being exposed to harsh salt and climatic conditions. This could exacerbate the incidence of wind erosion, resulting in the destabilization of well-defined and vegetated successional dunal zones.

  20. Environmental Impact of Artificial Harbors in Tropic Pacific Oceanic Islands

    Institute of Scientific and Technical Information of China (English)

    XUE Chunting; Russell Howorth; HE Chaoxiong

    2004-01-01

    For loading and unloading of boats or ships round the clock, the access channel and its expanded part-a port are excavated on the lagoon and ocean reef flats in the tropic Pacific oceanic islands. Without moles, the access channel-port traps sediment and further transports it to the ocean or lagoon, resulting in coastal erosion. The wide uneven reef flat with a large catchment area tends to cause the formation of tide currents in the channel-port, while strong waves on the narrow even reef flat can give rise to rip currents. An access channel-port with a mole on one side or two moles on both sides results in less erosion. A model is recommended as an artificial harbor on the ocean coast, which is an excavated port surrounded by a mole, connected with the ocean by an access channel and with the shore by a bridge-shaped pier.

  1. Subduction Complex Provenance redefined: modern sands from the Indo-Burman-Andaman-Nicobar Ridge and Barbados Island

    Science.gov (United States)

    Limonta, Mara; Resentini, Alberto; Andò, Sergio; Vezzoli, Giovanni; Bandopadhyay, Pinaki C.; Najman, Yani; Boni, Maria; Bechstädt, Thilo; Garzanti, Eduardo

    2013-04-01

    Subduction complexes large enough to be exposed subaerially and to become significant sources of terrigenous detritus are formed by tectonic accretion above trenches choked with thick sections of remnant-ocean turbidites. They thus need to be connected along strike to a large Alpine-type or Andean-type orogen, where huge volumes of orogenic detritus are produced and conveyed via a major fluvio-deltaic system to the deep sea (Ingersoll et al., 2003). We investigated sediment generation and recycling in the Indo-Burman-Andaman-Nicobar subduction complex, representing the archetype of such settings in the eastern prolongation of the Himalayan collisional system. "Subduction Complex Provenance" is composite, and chiefly consists of detritus recycled from largely turbiditic parent rocks (Recycled Clastic Provenance), with local supply from ultramafic and mafic rocks of forearc lithosphere (Ophiolite Provenance) or recycled paleovolcanic to neovolcanic sources (Volcanic Arc Provenance; Garzanti et al., 2007). In order to specifically investigate the effect of recycling, we characterized the diverse detrital signatures of Cenozoic sandstones deposited during subsequent stages of "soft" and "hard" Himalayan collision and exposed from Bangladesh to the Andaman Islands, and discuss the reasons for compositional discrepancies between parent sandstones and their recycled daughter sands. A companion study was carried out with the same methodologies, rationale and goals on Barbados Island, one of the few other places where a large accretionary prism is subaerially exposed. Also modern Barbados sands are largely multicyclic, reflecting mixing in various proportions of detritus from the basal Scotland Formation (sandstones and mudrocks), their stratigraphic and tectonic cover, the Oceanic Formation (quartzose turbidites and deep-water biogenic oozes including radiolarite), and from the Pleistocene calcarenite and reefal cap, as well as from volcanic layers ultimately derived from

  2. Ocean mixing beneath Pine Island Glacier Ice Shelf

    Science.gov (United States)

    Kimura, Satoshi; Dutrieux, Pierre; Jenkins, Adrian; Forryan, Alexander; Naveira Garabato, Alberto; Firing, Yvonne

    2016-04-01

    Ice shelves around Antarctica are vulnerable to increase in ocean-driven melting, with the melt rate depending on ocean temperature and strength of sub-ice-shelf-cavity circulations. We present repeated measurements of velocity, temperature, salinity, turbulent kinetic energy dissipation rate and thermal variance dissipation rate beneath Pine Island Glacier Ice Shelf, collected by CTD, ADCP and turbulence sensors mounted on an Autonomous Underwater Vehicle (AUV). The turbulence quantities measured by the AUV outside the ice shelf are in good agreement with ship-based measurements. The highest rate of turbulent kinetic energy dissipation is found near the grounding line, while its temporal fluctuation over seabed ridge within the cavity corresponds to the tidal fluctuation predicted in the Pine Island Bay to the west. The highest thermal variance dissipation rate is found when the AUV was 0.5 m away from the ice, and the thermal variance dissipation generally increases with decreasing distance between the AUV and ice.

  3. Seabirds of Easter Island, Salas y Gómez Island and Desventuradas Islands, southeastern Pacific Ocean

    OpenAIRE

    Flores,Marcelo A; Roberto P Schlatter; Rodrigo Hucke-Gaete

    2014-01-01

    We reviewed available information on seabirds inhabiting Easter Island, Salas y Gómez Island and Desventuradas Islands and their adjacent waters through an analysis of published and grey literature. Results obtained indicate that a total of 37 species are present in the study area and that, among the orders represented, the Procellariiformes and Charadriiformes are the dominant taxa (29 species). Moreover, the family Procellariidae is represented by 13 species and Laridae by 7 species. There ...

  4. Réunion (Indian Ocean) Oceanic Island Volcanism: Seismic Structure and Heterogeneity of the Upper Lithosphere

    Science.gov (United States)

    Hirn, A.

    2002-12-01

    Réunion island in the Indian Ocean is commonly considered as the recent and active expression of the hotspot that formed the Deccan traps, although both the hypothesis of recent small hotspots for both Reunion and Mauritius, or of relation with the plate heterogeneity have been proposed. Structural studies by seismic methods, from the scale of the upper cone of the active Fournaise volcano to that of the crust 100 km around, have been carried out. At this scale significant departures appear from the Hawaiian case to which it is traditionally compared, with the seismic signature of active volcanism showing differences too. Refraction-reflection seismics do not see a geometry of the top of the underlying plate towards the island, expected in plate flexure modelling by analogy with other hotspot island. Where it is sampled, doming is suggested instead. There appears to be less magmatic products than if there was a large amount buried in a flexural depression. The velocity structure resolved for the volcanic island, apart from high velocity cores under the volcanoes leads to smaller overall density than usually considered in flexure modelling. The same appears to hold for the material of the cone of about 120 km radius rising above the regional sea-bottom level to the 30 km radius island, from coincident reflection and refraction seismics on several lines radial to the southeastern half of the island. At the crust-mantle level, there is evidence from reflection-refraction line extending 150 km either side of the island for a layer of velocity intermediate between normal crust and mantle values. Two radial reflection line to the SSW, close to each other detect a differences in depth of the oceanic basement. This may coincide with a fracture zone suggested from the reconstruction of the sea-floor spreading history from the magnetic anomaly pattern. The latter has been interpreted previously to indicate that the western part of Réunion developed atop a Paleogene fossil

  5. Island effects on marine production and circulation around the island of South Georgia, Southern Ocean

    OpenAIRE

    2014-01-01

    In high-nutrient low-chlorophyll waters of the south-western Atlantic sector of the Southern Ocean, an intense phytoplankton bloom is observed annually north of South Georgia (37°W, 55°S). South Georgia blooms have a vital role in the ecosystem surrounding the island, and have been linked to one of the strongest seasonal atmospheric-carbon uptake in the open Southern Ocean. Which environmental conditions drive such remarkable productivity are still under debate, and were investigated in the c...

  6. Diel coral reef acidification driven by porewater advection in permeable sands, Heron Island, Great Barrier Reef

    DEFF Research Database (Denmark)

    Santos, Isaac R.; Glud, Ronnie N.; Maher, Damien

    2011-01-01

    Little is known about how biogeochemical processes in permeable sediments affect the pH of coastal waters. We demonstrate that seawater recirculation in permeable sands can play a major role in proton (H+) cycling in a coral reef lagoon. The diel pH range (up to 0.75 units) in the Heron Island...... lagoon was the broadest ever reported for reef waters, and the night‐time pH (7.69) was comparable to worst‐case scenario predictions for seawater pH in 2100. The net contribution of coarse carbonate sands to the whole system H+ fluxes was only 9% during the day, but approached 100% at night when small...... scale (i.e., flow and topography‐induced pressure gradients) and large scale (i.e., tidal pumping as traced by radon) seawater recirculation processes were synergistic. Reef lagoon sands were a net sink for H+, and the sink strength was a function of porewater flushing rate. Our observations suggest...

  7. Geothermal surveys in the oceanic volcanic island of Mauritius

    Science.gov (United States)

    Verdoya, Massimo; Chiozzi, Paolo; Pasqua, Claudio

    2017-04-01

    Oceanic island chains are generally characterised by young volcanic systems that are predominately composed of basaltic lavas and related magmatic products. Although hot springs are occasionally present, the pervasive, massive, recent outpourings of basaltic lavas are the primary manifestation of the existence of geothermal resources. These islands may have, in principle, significant potential for the exploitation of geothermal energy. In this paper, we present results of recent investigations aimed at the evaluation of geothermal resources of the island of Mauritius, that is the emerging portion of a huge submarine, aseismic, volcanic plateau extending in the SW part of the Indian Ocean. The plateau is related to a long-lived hotspot track, whose present-day expression is the active volcano of La Réunion Island, located about 200 km SW of Mauritius. The island does not show at present any volcanic activity, but magmatism is quite recent as it dates from 7.8 to 0.03 Myr. Geochemical data from water samples collected from boreholes do not indicate the presence of mature water, i.e. circulating in high-temperature geothermal reservoirs, and argue for short-term water-rock interaction in shallow hydrogeological circuits. However, this cannot rule out that a deep magmatic heat source, hydraulically insulated from shallow aquifers, may occur. To evaluate the geothermal gradient, a 270-m-deep hole was thus drilled in the island central portion, in which the most recent volcanic activity (0.03 Myr) took place. Temperature-depth profiles, recorded after complete thermal equilibration, revealed a thermal gradient of 40 mK/m. Attempts of extracting additional thermal information were also made by measuring the temperature in a 170-m-deep deep water hole, no longer used. The results were consistent with the gradient hole, i.e. pointing to a weak or null deep-seated thermal anomaly beneath Mauritius and low geothermal potential. The deep thermal process (mantle plume) invoked

  8. Mass culturing of living sands (Baculogypsina sphaerulata) to protect island coasts against sea-level rise

    Science.gov (United States)

    Hosono, Takashi; Lopati, Paeniu; Makolo, Filipo; Kayanne, Hajime

    2014-07-01

    Coral reef islands have a self-sustaining mechanism that expands and maintains the islands through the deposition of calcium carbonate (CaCO3) by marine organisms. However, the human societies established on such low-lying coral reef islands are vulnerable to rapid sea-level rises. Enhancing the self-sustaining mechanism of coral reefs will become one of the required sustainable countermeasures against sea-level rise. We examined the feasibility of mass culturing the large benthic foraminifera Baculogypsina sphaerulata, which is known as "living sand." We developed a rearing system with the key components of an artificial lawn as a habitat and a stirring device to create vertical water currents. Batches of B. sphaerulata in two different size groups were reared to examine size growth and reproduction under the culture conditions. All culture batches reproduced asexually following generations over 6 months in culture. The small-sized group exhibited steady growth, whereas the large-sized group underwent a reduction in mean size because large individuals (> 1.5 mm2) died off. Similar traits of size structure between the culture batches and natural populations indicate that our culturing conditions can successfully reproduce environments similar to the habitat of this species. Reproduction, consistent size growth, and size structure similar to the natural population indicate that the examined rearing system is viable for culturing Foraminifera at a large scale.

  9. The shallow stratigraphy and sand resources offshore of the Mississippi Barrier Islands

    Science.gov (United States)

    Twichell, David; Pendleton, Elizabeth A.; Baldwin, Wayne; Foster, David; Flocks, James; Kelso, Kyle; DeWitt, Nancy; Pfeiffer, William; Forde, Arnell; Krick, Jason; Baehr, John

    2011-01-01

    Coastal Mississippi is protected by a series of barrier islands ranging in length from 10-25 kilometers that are less than 2 kilometers wide. The majority of these islands comprise the Gulf Islands National Seashore (GUIS), an ecologically diverse shoreline that provides habitat for wildlife including migratory birds and endangered animals. The majority of GUIS is submerged, and aquatic environments include dynamic tidal inlets, ebb-tide deltas, and seagrass beds. The islands are in a state of decline, with land areas severely reduced during the past century by storms, sea-level rise, and human alteration. Morton (2008) estimates that since the mid-1800s up to 64 percent of island surface area has been lost. Heavy damage was inflicted in 2005 by Hurricane Katrina, which passed by as a Category 3 storm and battered the islands with winds of more than 160 kilometers per hour and a storm surge up to 9 meters. Since 2007, the U.S. Geological Survey (USGS), in collaboration with the National Park Service, has been mapping the seafloor and substrate around the islands as part of the USGS Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility project. The purpose of these investigations is to characterize the near-surface stratigraphy and identify the influence it may have on island evolution and fate. In 2009, this effort provided the basis for a collaborative effort with the U.S. Army Corps of Engineers (USACE) to expand the investigation outside of GUIS boundaries as part of the Mississippi Coastal Improvement Project (MsCIP). The MsCIP program consists of structural, nonstructural, and environmental project elements to restore portions of coastal Mississippi and GUIS affected by storm impact. The project includes the placement of sand along the islands, both on the present beaches and within the littoral zone, to mitigate shoreline erosion and breaching. This action requires the location and assessment of offshore sand or sediment deposits that can provide

  10. Oceanic barriers promote language diversification in the Japanese Islands.

    Science.gov (United States)

    Lee, S; Hasegawa, T

    2014-09-01

    Good barriers make good languages. Scholars have long speculated that geographical barriers impede linguistic contact between speech communities and promote language diversification in a manner similar to the process of allopatric speciation. This hypothesis, however, has seldom been tested systematically and quantitatively. Here, we adopt methods from evolutionary biology and attempt to quantify the influence of oceanic barriers on the degree of lexical diversity in the Japanese Islands. Measuring the degree of beta diversity from basic vocabularies, we find that geographical proximity and, more importantly, isolation by surrounding ocean, independently explains a significant proportion of lexical variation across Japonic languages. Further analyses indicate that our results are neither a by-product of using a distance matrix derived from a Bayesian language phylogeny nor an epiphenomenon of accelerated evolutionary rates in languages spoken by small communities. Moreover, we find that the effect of oceanic barriers is reproducible with the Ainu languages, indicating that our analytic approach as well as the results can be generalized beyond Japonic language family. The findings we report here are the first quantitative evidence that physical barriers formed by ocean can influence language diversification and points to an intriguing common mechanism between linguistic and biological evolution.

  11. Seabirds of Easter Island, Salas y Gómez Island and Desventuradas Islands, southeastern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Marcelo A Flores

    2014-10-01

    Full Text Available We reviewed available information on seabirds inhabiting Easter Island, Salas y Gómez Island and Desventuradas Islands and their adjacent waters through an analysis of published and grey literature. Results obtained indicate that a total of 37 species are present in the study area and that, among the orders represented, the Procellariiformes and Charadriiformes are the dominant taxa (29 species. Moreover, the family Procellariidae is represented by 13 species and Laridae by 7 species. There has been an increase in new records over the past six years but no systematic studies have been developed. The need for further research that focuses on ecological aspects and anthropogenic impacts is critical in order to develop adequate conservation strategies.

  12. Geomorphology and accommodation space as limiting factors on tsunami deposition: Chatham Island, southwest Pacific Ocean

    Science.gov (United States)

    Nichol, S. L.; Chagué-Goff, C.; Goff, J. R.; Horrocks, M.; McFadgen, B. G.; Strotz, L. C.

    2010-07-01

    Chatham Island in the southwest Pacific Ocean is exposed on all sides to potential tsunami impact. In historical time, tsunamis are known to have inundated the coast on several occasions, with the largest event in 1868. Coastal dunes along the northeast coast of Chatham Island preserve sedimentary evidence of this and possibly earlier tsunami events, as localised gravel lags. However, these deposits lack a clear stratigraphic context and establishing their age is difficult. This study examines the sediment record in a freshwater wetland at Okawa Point, located directly landward of the dunes where apparent tsunami gravels occur. Sediment descriptions, pollen, foraminifera, chemical data and radiocarbon dates from cores are used to reconstruct the environmental history of the wetland. The record extends from ca. > 43 ka to the present and incorporates glacial, post-glacial and human-influenced phases. Throughout this time the wetland appears to have remained isolated from catastrophic marine inundation. The only evidence for saltwater intrusion is observed in the historic period, via geochemical, grain size and pollen data, which record a marine inundation event that forced the transport of a thin (cm-thick) deposit of dune and beach sand into the seaward edge of the wetland. This is interpreted as the signature of the 1868 tsunami. The lack of more widespread physical evidence for this and other tsunami events in the wetland is attributed to the morphological roughness afforded by coastal dunes and limited accommodation space for Holocene deposits.

  13. The importance of shallow hydrothermal island arc systems in ocean biogeochemistry

    NARCIS (Netherlands)

    Hawkes, J.A.; Connelly, D.P.; Rijkenberg, M.J.A.; Achterberg, E.P.

    2014-01-01

    Hydrothermal venting often occurs at submarine volcanic calderas on island arc chains, typically at shallower depths than mid-ocean ridges. The effect of these systems on ocean biogeochemistry has been under-investigated to date. Here we show that hydrothermal effluent from an island arc caldera was

  14. Silicon isotopes reveal recycled altered oceanic crust in the mantle sources of Ocean Island Basalts

    Science.gov (United States)

    Pringle, Emily A.; Moynier, Frédéric; Savage, Paul S.; Jackson, Matthew G.; Moreira, Manuel; Day, James M. D.

    2016-09-01

    The study of silicon (Si) isotopes in Ocean Island Basalts (OIB) has the potential to discern between different models for the origins of geochemical heterogeneities in the mantle. Relatively large (∼several per mil per atomic mass unit) Si isotope fractionation occurs in low-temperature environments during biochemical and geochemical precipitation of dissolved Si, where the precipitate is preferentially enriched in the lighter isotopes relative to the dissolved Si. In contrast, only a limited range (∼tenths of a per mil) of Si isotope fractionation has been observed from high-temperature igneous processes. Therefore, Si isotopes may be useful as tracers for the presence of crustal material within OIB mantle source regions that experienced relatively low-temperature surface processes in a manner similar to other stable isotope systems, such as oxygen. Characterizing the isotopic composition of the mantle is also of central importance to the use of the Si isotope system as a basis for comparisons with other planetary bodies (e.g., Moon, Mars, asteroids). Here we present the first comprehensive suite of high-precision Si isotope data obtained by MC-ICP-MS for a diverse suite of OIB. Samples originate from ocean islands in the Pacific, Atlantic, and Indian Ocean basins and include representative end-members for the EM-1, EM-2, and HIMU mantle components. On average, δ30Si values for OIB (-0.32 ± 0.09‰, 2 sd) are in general agreement with previous estimates for the δ30Si value of Bulk Silicate Earth (-0.29 ± 0.07‰, 2 sd; Savage et al., 2014). Nonetheless, some small systematic variations are present; specifically, most HIMU-type (Mangaia; Cape Verde; La Palma, Canary Islands) and Iceland OIB are enriched in the lighter isotopes of Si (δ30Si values lower than MORB), consistent with recycled altered oceanic crust and lithospheric mantle in their mantle sources.

  15. Oceanic island biogeography through the lens of the general dynamic model

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Amorim, Isabel R.; Borges, Paulo A. V.

    2017-01-01

    The general dynamic model of oceanic island biogeography (GDM) has added a new dimension to theoretical island biogeography in recognizing that geological processes are key drivers of the evolutionary processes of diversification and extinction within remote islands. It provides a dynamic and ess...

  16. 77 FR 75853 - Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key West, FL

    Science.gov (United States)

    2012-12-26

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key... Island Triathlon on Saturday, January 12, 2013. The safety zone is necessary to provide for the safety of..., Questor Multisport, LLC is hosting the Bone Island Triathlon. The event will be held on the waters of...

  17. 78 FR 70901 - Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key West, FL

    Science.gov (United States)

    2013-11-27

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key..., during the Bone Island Triathlon on Saturday, January 25, 2014. The safety zone is necessary to provide... Multisport, LLC. is hosting the Bone Island Triathlon. The event will be held on the waters of the...

  18. Ocean mixing beneath Pine Island Glacier ice shelf, West Antarctica

    Science.gov (United States)

    Kimura, Satoshi; Jenkins, Adrian; Dutrieux, Pierre; Forryan, Alexander; Naveira Garabato, Alberto C.; Firing, Yvonne

    2016-12-01

    Ice shelves around Antarctica are vulnerable to an increase in ocean-driven melting, with the melt rate depending on ocean temperature and the strength of flow inside the ice-shelf cavities. We present measurements of velocity, temperature, salinity, turbulent kinetic energy dissipation rate, and thermal variance dissipation rate beneath Pine Island Glacier ice shelf, West Antarctica. These measurements were obtained by CTD, ADCP, and turbulence sensors mounted on an Autonomous Underwater Vehicle (AUV). The highest turbulent kinetic energy dissipation rate is found near the grounding line. The thermal variance dissipation rate increases closer to the ice-shelf base, with a maximum value found ˜0.5 m away from the ice. The measurements of turbulent kinetic energy dissipation rate near the ice are used to estimate basal melting of the ice shelf. The dissipation-rate-based melt rate estimates is sensitive to the stability correction parameter in the linear approximation of universal function of the Monin-Obukhov similarity theory for stratified boundary layers. We argue that our estimates of basal melting from dissipation rates are within a range of previous estimates of basal melting.

  19. Mechanisms driving variability in the ocean forcing of Pine Island Glacier

    Science.gov (United States)

    Webber, Benjamin G. M.; Heywood, Karen J.; Stevens, David P.; Dutrieux, Pierre; Abrahamsen, E. Povl; Jenkins, Adrian; Jacobs, Stanley S.; Ha, Ho Kyung; Lee, Sang Hoon; Kim, Tae Wan

    2017-02-01

    Pine Island Glacier (PIG) terminates in a rapidly melting ice shelf, and ocean circulation and temperature are implicated in the retreat and growing contribution to sea level rise of PIG and nearby glaciers. However, the variability of the ocean forcing of PIG has been poorly constrained due to a lack of multi-year observations. Here we show, using a unique record close to the Pine Island Ice Shelf (PIIS), that there is considerable oceanic variability at seasonal and interannual timescales, including a pronounced cold period from October 2011 to May 2013. This variability can be largely explained by two processes: cumulative ocean surface heat fluxes and sea ice formation close to PIIS; and interannual reversals in ocean currents and associated heat transport within Pine Island Bay, driven by a combination of local and remote forcing. Local atmospheric forcing therefore plays an important role in driving oceanic variability close to PIIS.

  20. The late Quaternary decline and extinction of palms on oceanic Pacific islands

    Science.gov (United States)

    Prebble, M.; Dowe, J. L.

    2008-12-01

    Late Quaternary palaeoecological records of palm decline, extirpation and extinction are explored from the oceanic islands of the Pacific Ocean. Despite the severe reduction of faunal diversity coincidental with human colonisation of these previously uninhabited oceanic islands, relatively few plant extinctions have been recorded. At low taxonomic levels, recent faunal extinctions on oceanic islands are concentrated in larger bodied representatives of certain genera and families. Fossil and historic records of plant extinction show a similar trend with high representation of the palm family, Arecaceae. Late Holocene decline of palm pollen types is demonstrated from most islands where there are palaeoecological records including the Cook Islands, Fiji, French Polynesia, the Hawaiian Islands, the Juan Fernandez Islands and Rapanui. A strong correspondence between human impact and palm decline is measured from palynological proxies including increased concentrations of charcoal particles and pollen from cultivated plants and invasive weeds. Late Holocene extinctions or extirpations are recorded across all five of the Arecaceae subfamilies of the oceanic Pacific islands. These are most common for the genus Pritchardia but also many sedis fossil palm types were recorded representing groups lacking diagnostic morphological characters.

  1. Genetically depauperate in the continent but rich in oceanic islands: Cistus monspeliensis (Cistaceae in the Canary Islands.

    Directory of Open Access Journals (Sweden)

    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

  2. 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.

  3. The coherence of small island sea-level with the wider ocean: a model study

    Directory of Open Access Journals (Sweden)

    Joanne Williams

    2012-09-01

    Full Text Available Studies comparing tide gauge measurements with sea level from nearby satellite altimetry have shown good agreement for some islands, and poor agreement for others, though no explanation has been offered. Using the 1/12° OCCAM ocean model, we investigate the relationship between sea level at small, open-ocean islands, and offshore sea level. For every such island or seamount in the model, we compare the shallow-water sea level with the steric and bottom pressure variability in a neighboring ring of deep water. We find a latitude-dependent range of frequencies for which off-shore sea level is poorly correlated with island sea level. This poor coherence occurs in a spectral region for which steric signals dominate, but are unable to propagate as baroclinic Rossby waves. This mode of decoupling does not arise because of island topography, as the same decoupling is seen between deep ocean points and surrounding rings.

  4. Thermal structure and flow patterns around Seychelles group of Islands (Indian Ocean) during austral autumn

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.; RameshBabu, V.; RameshKumar, M.R.

    Properties of thermal structure in the upper 750 m around the Seychelles group of islands in the Indian Ocean, based on Expendable Bathythermograph (XBT) data collected in March 1984, are presented along with the inferred flow patterns...

  5. Island-Arc Collision Dominates Japan's Sediment Flux to the Pacific Ocean

    Science.gov (United States)

    Codilean, A. T.; Korup, O.; Hayakawa, Y. S.; Matsushi, Y.; Saito, H.; Matsuzaki, H.

    2013-12-01

    Quantifying volumes and rates of delivery of terrestrial sediment to subduction zones is indispensable for refining estimates of the thickness of trench fills that may eventually control the location and timing of submarine landslides and tsunami-generating mega-earthquakes. Despite these motivating insights, knowledge about the rates of erosion and sediment export from the Japanese islands to their Pacific subduction zones has somewhat stagnated despite the increasing availability of highly resolved data on surface deformation, climate, geology, and topography. Traditionally, natural erosion rates across the island arc have been estimated from catchment topographic predictors of reservoir sedimentation rates that were recorded over several years to decades. We correct for a systematic bias in these predictions, and present new estimates of decadal to millennial-scale erosion rates of the Japanese terrestrial inner forearc, drawing on several unprecedented inventories of mass wasting, reservoir sedimentation, and concentrations of cosmogenic 10Be in river sands. Our data reveal that catchments draining Japan's eastern seaboard have distinctly different tectonic, lithological, topographic, and climatic characteristics, underscored by a marked asymmetric pattern of erosion rates along and across the island arc. Erosion rates are highest in the Japanese Alps that mark the collision of two subduction zones, where high topographic relief, hillslope and bedrock-channel steepness foster rapid denudation by mass wasting. Comparable, if slightly lower, rates characterize southwest Japan, most likely due to higher typhoon-driven rainfall totals and variability rather than the similarly high relief and contemporary uplift rates that are linked to subduction earthquake cycles, and outpace long-term Quaternary uplift. In contrast, our estimated erosion and flux rates are lowest in the inner forearc catchments that feed sediment into the Japan Trench. We conclude that

  6. Habitat selection of two island-associated dolphin species from the south-west Indian Ocean

    Science.gov (United States)

    Condet, Manon; Dulau-Drouot, Violaine

    2016-08-01

    Identifying suitable habitats of protected species is an essential question in ecology and conservation planning. Modelling approaches have been widely used to identify environmental features that contribute to a species' ecological requirements and distribution. On Reunion Island, a fast-growing French territory located in the south-western Indian Ocean, anthropogenic impacts are mainly concentrated along the coast, representing a potential threat for Indo-Pacific bottlenose (Tursiops aduncus) and spinner (Stenella longirostris) dolphins, two resident coastal species. Beside coastal development, commercial and recreational dolphin-watching are growing, particularly along the west coast. To promote effective local management, habitat modelling was applied using presence-only data collected from 2008 to 2012 on the west coast of the island. Ecological Niche Factor Analyses were used to investigate the effect of physiographic variables on the distribution of these two dolphin species and delineate suitable habitats. It was found that the core habitat of Indo-Pacific bottlenose dolphins was mainly restricted by depth and confined to coastal waters ranging from 4.7 to 75.8 m deep. The species preferentially used soft substrates (sand and mud) and tended to be ubiquitous in terms of substrate type/color used. Foraging activities were significantly related to soft substrates. The diurnal core habitat of spinner dolphins was confined to one discrete area, on the flat portion of the insular shelf, between 45.1 m and 70.7 m of depth. Suitable habitat was mainly related to soft and light-colored substrates, with a clear avoidance of dark-colored substrates. The core habitats of both species were very restrained spatially and therefore vulnerable to human activities. The fine scale habitat mapping achieved in this study represents baseline data to conduct ad hoc impact assessment and support conservation actions.

  7. 33 CFR 334.1360 - Pacific Ocean at Barber's Point, Island of Oahu, Hawaii; danger zone.

    Science.gov (United States)

    2010-07-01

    ..., Island of Oahu, Hawaii; danger zone. 334.1360 Section 334.1360 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1360 Pacific Ocean at Barber's Point, Island of Oahu, Hawaii; danger zone. (a) The danger zone....

  8. 33 CFR 334.1370 - Pacific Ocean at Keahi Point, Island of Oahu, Hawaii; danger zone.

    Science.gov (United States)

    2010-07-01

    ..., Island of Oahu, Hawaii; danger zone. 334.1370 Section 334.1370 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1370 Pacific Ocean at Keahi Point, Island of Oahu, Hawaii; danger zone. (a) The danger zone. The...

  9. 33 CFR 334.1140 - Pacific Ocean at San Miguel Island, Calif.; naval danger zone.

    Science.gov (United States)

    2010-07-01

    ... Island, Calif.; naval danger zone. 334.1140 Section 334.1140 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1140 Pacific Ocean at San Miguel Island, Calif.; naval danger zone. (a) The area. The waters around...

  10. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Science.gov (United States)

    2010-07-01

    ... Island, California; Navy shore bombardment areas. 334.950 Section 334.950 Navigation and Navigable Waters... REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The... degrees true, 5.35 nautical miles; thence 040.4 degrees true to the beach. (3) The waters of the...

  11. 33 CFR 110.220 - Pacific Ocean at San Nicolas Island, Calif.; restricted anchorage areas.

    Science.gov (United States)

    2010-07-01

    ... Pacific Ocean at San Nicolas Island, Calif.; restricted anchorage areas. (a) The restricted areas—(1) East area. All waters within a circle having a radius of one nautical mile centered at latitude 33°13′45... approximately 101°, 420 yards, from San Nicolas Island East End Light. (2) West area. Shoreward of a...

  12. Oceanic island biogeography through the lens of the general dynamic model: assessment and prospect

    DEFF Research Database (Denmark)

    Borregaard, Michael; Amorim, Isabel; Borges, Paulo;

    2016-01-01

    and in developing and enhancing ecological–evolutionary understanding of oceanic island systems through the lens of the GDM. In particular, we focus on four main themes: (i) macroecological tests using a space-for-time rationale; (ii) extensions of theory to islands following different patterns of ontogeny; (iii...... demonstrate the vitality of the field of island biogeography by identifying a range of potentially productive lines for future research....

  13. Silicon isotopes reveal recycled altered oceanic crust in the mantle sources of Ocean Island Basalts

    CERN Document Server

    Pringle, Emily A; Savage, Paul S; Jackson, Matthew G; Day, James M D

    2016-01-01

    The study of silicon (Si) isotopes in ocean island basalts (OIB) has the potential to discern between different models for the origins of geochemical heterogeneities in the mantle. Relatively large (several per mil per atomic mass unit) Si isotope fractionation occurs in low-temperature environments during biochemical and geochemical precipitation of dissolved Si, where the precipitate is preferentially enriched in the lighter isotopes relative to the dissolved Si. In contrast, only a limited range (tenths of a per mil) of Si isotope fractionation has been observed from high-temperature igneous processes. Therefore, Si isotopes may be useful as tracers for the presence of crustal material within OIB mantle source regions that experienced relatively low-temperature surface processes in a manner similar to other stable isotope systems, such as oxygen. Characterizing the isotopic composition of the mantle is also of central importance to the use of the Si isotope system as a basis for comparisons with other plan...

  14. Sand Resources, Regional Geology, and Coastal Processes of the Chandeleur Islands Coastal System: an Evaluation of the Breton National Wildlife Refuge

    Science.gov (United States)

    Lavoie, Dawn

    2009-01-01

    Breton National Wildlife Refuge, the Chandeleur Islands chain in Louisiana, provides habitat and nesting areas for wildlife and is an initial barrier protecting New Orleans from storms. The U.S. Geological Survey (USGS) in partnership with the University of New Orleans Pontchartrain Institute for Environmental Sciences undertook an intensive study that included (1) an analysis of island change based on historical maps and remotely sensed shoreline and topographic data; (2) a series of lidar surveys at 3- to 4-month intervals after Hurricane Katrina to determine barrier island recovery potential; (3) a discussion of sea level rise and effects on the islands; (4) an analysis of sea floor evolution and sediment dynamics in the refuge over the past 150 years; (5) an assessment of the local sediment transport and sediment resource availability based on the bathymetric and subbottom data; (6) a carefully selected core collection effort to groundtruth the geophysical data and more fully characterize the sediments composing the islands and surrounds; (7) an additional survey of the St. Bernard Shoals to assess their potential as a sand resource; and (8) a modeling study to numerically simulate the potential response of the islands to the low-intensity, intermediate, and extreme events likely to affect the refuge over the next 50 years. Results indicate that the islands have become fragmented and greatly diminished in subaerial extent over time: the southern islands retreating landward as they reorganize into subaerial features, the northern islands remaining in place. Breton Island, because maintenance of the Mississippi River-Gulf Outlet (MRGO) outer bar channel requires dredging, is deprived of sand sufficient to sustain itself. Regional sediment transport trends indicate that large storms are extremely effective in transporting sand and controlling the shoreline development and barrier island geometry. Sand is transported north and south from a divergent zone near

  15. Land-cover types, shoreline positions, and sand extents derived From Landsat satellite imagery, Assateague Island to Metompkin Island, Maryland and Virginia, 1984 to 2014

    Science.gov (United States)

    Bernier, Julie C.; Douglas, Steven H.; Terrano, Joseph F.; Barras, John A.; Plant, Nathaniel G.; Smith, Christopher G.

    2015-12-17

    The U.S. Geological Survey has a long history of responding to and documenting the impacts of storms along the Nation’s coasts and incorporating these data into storm impact and coastal change vulnerability assessments. These studies, however, have traditionally focused on sandy shorelines and sandy barrier-island systems, without consideration of impacts to coastal wetlands. The goal of the Barrier Island and Estuarine Wetland Physical Change Assessment project is to integrate a wetland-change assessment with existing coastal-change assessments for the adjacent sandy dunes and beaches, initially focusing on Assateague Island along the Maryland and Virginia coastline. Assateague Island was impacted by waves and storm surge associated with the passage of Hurricane Sandy in October 2012, including erosion and overwash along the ocean-facing sandy shoreline as well as erosion and overwash deposition in the back-barrier and estuarine bay environments.

  16. Metasomatism in the oceanic lithosphere beneath La Palma, Canary Islands

    Science.gov (United States)

    Janisch, Astrid; Ntaflos, Theodoros

    2016-04-01

    La Palma is the most active island within the Canary archipelago with historical eruption along the Cumbre Vieja Rift. Mantle peridotite xenoliths brought to the surface during the eruption 1677/78 at the site of San Antonio Volcano, close to Fuencaliente in the south of the island, gives us an excellent opportunity to study an old oceanic lithosphere. The collection of xenoliths comprises sp-harzburgites, sp-lherzolites, sp-dunites and pyroxenites but only the first three were used for this work. Metasomatic processes are evident in all samples. A common feature is a variable channelling of melt flow through the mantle xenoliths displayed in variations from pervasively metasomatized, through veined to dyke intruded peridotites. Orthopyroxene breakdown into olivine, clinopyroxene and glass is evidence for anhydrous melt percolation. Furthermore, fine-grained veins in various thicknesses consisting of olivine, pyroxene as well as amphibole with apatite and phlogopite reveal additional anhydrous and hydrous metasomatic processes, respectively. Peridotites mainly influenced by anhydrous metasomatism exhibit locally phlogopite and/or amphibole around spinel or in glass-veinlets. Pentlandite has been found in all veined samples. Amphiboles are mostly pargasites but kaersutites are also present in the amphibole-bearing veins. Two different types of amphibole veins have been recognized. The first type is an amphibole-apatite-glass-bearing amphibolite, forming a cross-cutting vein that propagates through the xenolith. The amphiboles in this vein are coarse-grained while the disseminated amphiboles are fine-grained. Clinopyroxene always occurs in association with amphibole and in textural equilibrium suggesting that both minerals have grown together. The glass is of tephritic/basanitic to trachy-basaltic composition. The second amphibole-vein contains phlogopite and traces of apatite. Textural evidence (cross-cutting olivine grains and the absence of hydrous minerals in the

  17. Assessment of natural radioactivity and gamma-ray dose in monazite rich black Sand Beach of Penang Island, Malaysia.

    Science.gov (United States)

    Shuaibu, Hauwau Kulu; Khandaker, Mayeen Uddin; Alrefae, Tareq; Bradley, D A

    2017-06-15

    Activity concentrations of primordial radionuclides in sand samples collected from the coastal beaches surrounding Penang Island have been measured using conventional γ-ray spectrometry, while in-situ γ-ray doses have been measured through use of a portable radiation survey meter. The mean activity concentrations for (226)Ra, (232)Th and (40)K at different locations were found to be less than the world average values, while the Miami Bay values for (226)Ra and (232)Th were found to be greater, at 1023±47 and 2086±96Bqkg(̶ 1) respectively. The main contributor to radionuclide enrichment in Miami Bay is the presence of monazite-rich black sands. The measured data were compared against literature values and also recommended limits set by the relevant international bodies. With the exception of Miami Bay, considered an elevated background radiation area that would benefit from regular monitoring, Penang island beach sands typically pose no significant radiological risk to the local populace and tourists visiting the leisure beaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Helminth parasites of the oceanic horse mackerel Trachurus picturatus Bowdich 1825 (Pisces: Carangidae) from Madeira Island, Atlantic Ocean, Portugal.

    Science.gov (United States)

    Costa, G; Melo-Moreira, E; Pinheiro de Carvalho, M A A

    2012-09-01

    The helminth parasite fauna of the oceanic horse mackerel Trachurus picturatus Bowdich 1825, caught off the Madeira Islands was composed of six different taxa. Prevalence and abundance of larval Anisakis sp. (Nematoda: Anisakidae) and Nybelinia lingualis (Trypanorhyncha: Tentaculariidae), the most common parasite taxa, were 24.3%, 0.9 and 37.9%, 0.7, respectively. Bolbosoma vasculosum (Acanthocephala: Polymorphidae) and the monogeneans Heteraxinoides atlanticus (Monogenea: Heteraxinidae) and Pseudaxine trachuri (Monogenea: Gastrocotylidae) were comparatively rare. The depauperate helminth fauna of the oceanic horse mackerel at Madeira compared to other geographical regions of the north-eastern Atlantic, namely the Azores banks and the West African coast, may be attributed to the paucity of nutrients off oceanic islands and to a low density of the fish population.

  19. Submarine structure of Reunion Island (Indian Ocean) inferred from gravity

    Science.gov (United States)

    Gailler, L.; Lénat, J.

    2008-12-01

    La Reunion is a large (diameter: 220 km; height: 7 km), mostly immerged (97%) oceanic volcanic system. New land and marine gravity data are used to study the structure of its submarine part. The gravity models are interpreted jointly with the published geology interpretations and compared with magnetic models. This allows us to derive a new model of the shallow and internal structure of the submarine flanks. Recent cruises have collected high quality gravity, magnetic and multi-beam swath bathymetry data over the submarine flanks of La Réunion and the surrounding oceanic plate. A new Bouguer anomaly map has been computed for a reduction density of 2.67.103 kg m-3. A magnetic anomalies map covering the same area has been also built. Studies based on bathymetric and acoustic data have previously shown the presence of different types of submarine features: a coastal shelf, huge bulges built by debris avalanches and sediment deposits, erosion canyons, volcanic constructions near the coast, isolated seamounts offshore, and elongate volcanic ridges on the Mascarene plate. On the new Bouguer anomaly map, all these features are associated with negative anomalies. They have been modeled using 2 3/4 D modeling techniques. The short wavelength anomalies over the coastal shelf area can be explained by piles of low density layers. This suggests that they are mostly built by hyaloclastites which are generally characterized by lower densities than lava flows. The voluminous debris avalanche deposits which formed the huge Submarine Bulges to the east, north, west, and south of the island have also been modeled as low density formations. Each bulge is modeled with an overall density less than 2.67.103 kg m-3, in order to account for its long wavelength anomaly. Some shorter wavelength features are superimposed on these long wavelength negative anomalies. They probably represent heterogeneities within the bulges. Some shallow ones can be associated with observed surface geological

  20. Non-Dive Activities for Islands in the Stream 2002 - Pharmaceutical Discovery, Vision, and Bioluminescence - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Expeditions Information System (EIS) contains information recorded by the NOAA Office of Ocean Exploration's data manager during the 2002 "Islands in the Stream...

  1. Dive Data from Expedition Information System (EIS) for Islands in the Stream 2002 - Deep Reef Habitat - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Expeditions Information System (EIS) contains information recorded by the NOAA Office of Ocean Exploration's data manager during the 2002 "Islands in the Stream...

  2. Oceanic, island arc, and back-arc remnants into eastern Kamchatka accretionary complexes

    Energy Technology Data Exchange (ETDEWEB)

    Fedorchuk, A.V.; Vishnevskaya, V.S.; Izvekov, I.N. (Institute of the Lithosphere, Moscow (USSR))

    1990-06-01

    The Kamchatsky Mts. accretionary complex in the Eastern Kamchatka orogenic belt was studied for identification of the oceanic and suprasubduction components into accretionary wedges. That complex is divided into two tectonic units. The Lower unit is formed sedimentary and tectonic melanges containing arc-related components (Late Senonian volcaniclastics and boninitic gabbro) and oceanic fragments (Fe-Ti-tholeiites, ocean island basalts, and pelagic sediments of Valanginian to Turonian age). The Upper unit consists of ductile deformed oceanic cumulates from troctolites to Fe-Ti-gabbro, 151 to 172 Ma, which are intruded MORB-like diabases with suprasubduction characteristics, 122 to 141 Ma, and are overlain by basalts similar to latter. The Lower and Upper units are separated by a SW-dipping thrust, which is related by an ophiolitoclastic olistostrome of Late Campanian to Early Maestrichtian age. Both units are covered by Paleocene authoclastic deposits. They are all thrusted over the early Neogene island arc complex, 16 to 20 Ma. The Lower unit of the Kamchatsky Mys accretionary complex was originated in a shear zone between a Late Cretaceous island arc and an Early Cretaceous oceanic plate. The Upper unit represents a Jurassic oceanic remnant that formed a basement of Early Cretaceous back-arc or fore-arc basin. Both units were superposed in the latest Cretaceous. The Kamchatsky Mys accretionary complex was emplaced into the Eastern Kamchatka orogenic belt during late Neogene by collision of the early Neogene island arc.

  3. Biostratigraphic evidence for dramatic Holocene uplift of Robinson Crusoe Island, Juan Fernández Ridge, SE Pacific Ocean

    Science.gov (United States)

    Sepúlveda, P.; Le Roux, J. P.; Lara, L. E.; Orozco, G.; Astudillo, V.

    2015-03-01

    Hotspot oceanic islands typically experience subsidence due to several processes related to migration of the oceanic plate away from the mantle plume and surface flexural loading. However, many other processes can interrupt subsidence, some of which may be associated with catastrophic events. A study of the biostratigraphy and sedimentology of Holocene deposits on Robinson Crusoe Island (RCI) on the Juan Fernández Ridge (JFR) indicated that dramatic uplift has occurred since 8000 years BP, at a rate of about 8.5mm yr-1. This is evidenced by supratidal flats with tepee structures and sand layers containing marine gastropods (mostly Nerita sp.) that are now exposed ca. 70 m a.s.l. The active hotspot is located 280 km further west and the last volcanic activity on RCI occurred at ca. 800 000 years BP. Long-term subsidence is evidenced by deep submerged marine abrasion terraces at RCI. As no direct evidence was found for the existence of a compensating bulge generated by the present hotspot upon which RCI would be situated, it must be concluded that subsidence in the wake of the mantle plume beneath the migrating plate was interrupted by very rapid uplift, but on a scale that did not fully compensate for the previous subsidence. This can be attributed to large-scale landslides followed by isostatic rebound, although this is only vaguely reflected in the low-resolution bathymetry of the area. To determine if this mechanism produced the uplift, a detailed bathymetric survey of the area will be required. If such a survey confirms this hypothesis, it may have implications for the short-term dynamics of vertical variations of oceanic edifices and their related effects on ecosystems and human population.

  4. Geochemical characteristics of the oceanic island- type volcanic rocks in the Chiang Mai zone, northern Thailand

    Institute of Scientific and Technical Information of China (English)

    SHEN Shangyue; FENG Qinglai; ZHANG Zhibin; CHONGPAN Chonglakmani

    2009-01-01

    The oceanic island volcanic rocks in the Chiang Mai zone, northern Thailand, are usually covered by Lower Carboniferous and Upper Permian shallow-water carbonate rocks, with the Hawaii rocks and potash trachybasalt being the main rock types. The alkaline series is dominant with sub-alkaline series occurring in few cases. The geochemical characteristics are described as follows: the major chemical compositions are characterized by high TiO2, high P2O5 and medium K2O; the rare-earth elements are characterized by right-inclined strong LREE-enrichment patterns; the trace element patterns are of the upward-bulging K-Ti enrichment type; multi-component plots falling within the fields of oceanic island basalts and alkali basalts, belonging to the oceanic island-type volcanic rocks, which are similar to the equivalents in Deqin and Gengma (the Changning-Menglian zone) of Yunnan Province, China.

  5. Recent and rapid radiation of the lichen genus Sticta in the Western Indian Ocean islands

    OpenAIRE

    Simon, Antoine; Magain, Nicolas; Goffinet, Bernard; Sérusiaux, Emmanuël

    2016-01-01

    In the framework of a global project on the phylogeny of the lichen genus Sticta (Lobariaceae), extensive sampling was performed on the islands of Reunion and Mauritius as well as in several parts of Madagascar (mainly in two National Parks : Marojejy and Amber Mountain). The aim of this study is to provide the first comprehensive molecular phylogeny of the genus in the Western Indian Ocean islands (and more specifically of a presumably local endemic lineage), and to date its local radiation....

  6. Effects of ocean acidification on the swimming ability, development and biochemical responses of sand smelt larvae.

    Science.gov (United States)

    Silva, Cátia S E; Novais, Sara C; Lemos, Marco F L; Mendes, Susana; Oliveira, Ana P; Gonçalves, Emanuel J; Faria, Ana M

    2016-09-01

    Ocean acidification, recognized as a major threat to marine ecosystems, has developed into one of the fastest growing fields of research in marine sciences. Several studies on fish larval stages point to abnormal behaviours, malformations and increased mortality rates as a result of exposure to increased levels of CO2. However, other studies fail to recognize any consequence, suggesting species-specific sensitivity to increased levels of CO2, highlighting the need of further research. In this study we investigated the effects of exposure to elevated pCO2 on behaviour, development, oxidative stress and energy metabolism of sand smelt larvae, Atherina presbyter. Larvae were caught at Arrábida Marine Park (Portugal) and exposed to different pCO2 levels (control: ~600μatm, pH=8.03; medium: ~1000μatm, pH=7.85; high: ~1800μatm, pH=7.64) up to 15days, after which critical swimming speed (Ucrit), morphometric traits and biochemical biomarkers were determined. Measured biomarkers were related with: 1) oxidative stress - superoxide dismutase and catalase enzyme activities, levels of lipid peroxidation and DNA damage, and levels of superoxide anion production; 2) energy metabolism - total carbohydrate levels, electron transport system activity, lactate dehydrogenase and isocitrate dehydrogenase enzyme activities. Swimming speed was not affected by treatment, but exposure to increasing levels of pCO2 leads to higher energetic costs and morphometric changes, with larger larvae in high pCO2 treatment and smaller larvae in medium pCO2 treatment. The efficient antioxidant response capacity and increase in energetic metabolism only registered at the medium pCO2 treatment may indicate that at higher pCO2 levels the capacity of larvae to restore their internal balance can be impaired. Our findings illustrate the need of using multiple approaches to explore the consequences of future pCO2 levels on organisms.

  7. Sand and nest temperatures and an estimate of hatchling sex ratio from the Heron Island green turtle ( Chelonia mydas) rookery, Southern Great Barrier Reef

    Science.gov (United States)

    Booth, David T.; Freeman, Candida

    2006-11-01

    Sand and nest temperatures were monitored during the 2002-2003 nesting season of the green turtle, Chelonia mydas, at Heron Island, Great Barrier Reef, Australia. Sand temperatures increased from ˜ 24°C early in the season to 27-29°C in the middle, before decreasing again. Beach orientation affected sand temperature at nest depth throughout the season; the north facing beach remained 0.7°C warmer than the east, which was 0.9°C warmer than the south, but monitored nest temperatures were similar across all beaches. Sand temperature at 100 cm depth was cooler than at 40 cm early in the season, but this reversed at the end. Nest temperatures increased 2-4°C above sand temperatures during the later half of incubation due to metabolic heating. Hatchling sex ratio inferred from nest temperature profiles indicated a strong female bias.

  8. Sand ridge morphology and bedform migration patterns derived from bathymetry and backscatter on the inner-continental shelf offshore of Assateague Island, USA

    Science.gov (United States)

    Pendleton, Elizabeth; Brothers, Laura; Thieler, E. Robert; Sweeney, Edward

    2017-01-01

    The U.S. Geological Survey and the National Oceanographic and Atmospheric Administration conducted geophysical and hydrographic surveys, respectively, along the inner-continental shelf of Fenwick and Assateague Islands, Maryland and Virginia over the last 40 years. High resolution bathymetry and backscatter data derived from surveys over the last decade are used to describe the morphology and presence of sand ridges on the inner-continental shelf and measure the change in the position of smaller-scale (10–100 s of meters) seafloor features. Bathymetric surveys from the last 30 years link decadal-scale sand ridge migration patterns to the high-resolution measurements of smaller-scale bedform features. Sand ridge morphology on the inner-shelf changes across-shore and alongshore. Areas of similar sand ridge morphology are separated alongshore by zones where ridges are less pronounced or completely transected by transverse dunes. Seafloor-change analyses derived from backscatter data over a 4–7 year period show that southerly dune migration increases in magnitude from north to south, and the east-west pattern of bedform migration changes ~ 10 km north of the Maryland-Virginia state line. Sand ridge morphology and occurrence and bedform migration changes may be connected to observed changes in geologic framework including topographic highs, deflated zones, and sand availability. Additionally, changes in sand ridge occurrence and morphology may help explain changes in the long-term shoreline trends along Fenwick and Assateague Islands. Although the data presented here cannot quantitatively link sand ridges to sediment transport and shoreline change, it does present a compelling relationship between inner-shelf sand availability and movement, sand ridge occurrence and morphology, geologic framework, and shoreline behavior.

  9. Sand ridge morphology and bedform migration patterns derived from bathymetry and backscatter on the inner-continental shelf offshore of Assateague Island, USA

    Science.gov (United States)

    Pendleton, Elizabeth A.; Brothers, Laura L.; Thieler, E. Robert; Sweeney, Edward M.

    2017-07-01

    The U.S. Geological Survey and the National Oceanographic and Atmospheric Administration conducted geophysical and hydrographic surveys, respectively, along the inner-continental shelf of Fenwick and Assateague Islands, Maryland and Virginia over the last 40 years. High resolution bathymetry and backscatter data derived from surveys over the last decade are used to describe the morphology and presence of sand ridges on the inner-continental shelf and measure the change in the position of smaller-scale (10-100 s of meters) seafloor features. Bathymetric surveys from the last 30 years link decadal-scale sand ridge migration patterns to the high-resolution measurements of smaller-scale bedform features. Sand ridge morphology on the inner-shelf changes across-shore and alongshore. Areas of similar sand ridge morphology are separated alongshore by zones where ridges are less pronounced or completely transected by transverse dunes. Seafloor-change analyses derived from backscatter data over a 4-7 year period show that southerly dune migration increases in magnitude from north to south, and the east-west pattern of bedform migration changes 10 km north of the Maryland-Virginia state line. Sand ridge morphology and occurrence and bedform migration changes may be connected to observed changes in geologic framework including topographic highs, deflated zones, and sand availability. Additionally, changes in sand ridge occurrence and morphology may help explain changes in the long-term shoreline trends along Fenwick and Assateague Islands. Although the data presented here cannot quantitatively link sand ridges to sediment transport and shoreline change, it does present a compelling relationship between inner-shelf sand availability and movement, sand ridge occurrence and morphology, geologic framework, and shoreline behavior.

  10. Vegetation and checklist of Inaccessible Island, central South Atlantic Ocean, with notes on Nightingale Island

    Directory of Open Access Journals (Sweden)

    J. P. Roux

    1992-12-01

    Full Text Available The physiography and climate of Inaccessible and Nightingale Islands are briefly discussed. The vegetation and the major plant associations are described. Notes are given on the ecology and distribution of each taxon. Taxa newly recorded for Inaccessible Island include Agrostis goughensis, A.holgateana, A. wacei, Calamagrostis deschampsiiformis, Carex thouarsii var.  recurvata, Conyza albida, Elaphoglossum campylolepium and  Uncinia meridensis. One species, C.  albida, is alien to the Tristan group. Two native ferns Asplenium platybasis var.  subnudum and Blechnum australe were found on Nightingale Island for the first time, and the presence of introduced Malus domestica orchards was recorded. Two unidentified taxa were found that may represent new species:  Elaphoglossum sp. at Inaccessible Island and Apium sp. at both Inaccessible and Nightingale Islands. The total number of vascular plant species recorded at Inaccessible and Nightingale Islands now stands at 98 and 43, respectively, of which 26 (28% and seven (16% are introduced species. Only Airiplex plebeja and two species of Cotula occur at Nightingale Island but are absent from Inaccessible Island.

  11. Vegetation and checklist of Inaccessible Island, central South Atlantic Ocean, with notes on Nightingale Island

    Directory of Open Access Journals (Sweden)

    J. P. Roux

    1992-12-01

    Full Text Available The physiography and climate of Inaccessible and Nightingale Islands are briefly discussed. The vegetation and the major plant associations are described. Notes are given on the ecology and distribution of each taxon. Taxa newly recorded for Inaccessible Island include Agrostis goughensis, A.holgateana, A. wacei, Calamagrostis deschampsiiformis, Carex thouarsii var.  recurvata, Conyza albida, Elaphoglossum campylolepium and  Uncinia meridensis. One species, C.  albida, is alien to the Tristan group. Two native ferns Asplenium platybasis var.  subnudum and Blechnum australe were found on Nightingale Island for the first time, and the presence of introduced Malus domestica orchards was recorded. Two unidentified taxa were found that may represent new species:  Elaphoglossum sp. at Inaccessible Island and Apium sp. at both Inaccessible and Nightingale Islands. The total number of vascular plant species recorded at Inaccessible and Nightingale Islands now stands at 98 and 43, respectively, of which 26 (28% and seven (16% are introduced species. Only Airiplex plebeja and two species of Cotula occur at Nightingale Island but are absent from Inaccessible Island.

  12. Speciation on oceanic islands: rapid adaptive divergence vs. cryptic speciation in a Guadalupe Island songbird (Aves: Junco.

    Directory of Open Access Journals (Sweden)

    Pau Aleixandre

    Full Text Available The evolutionary divergence of island populations, and in particular the tempo and relative importance of neutral and selective factors, is of central interest to the study of speciation. The rate of phenotypic evolution upon island colonization can vary greatly among taxa, and cases of convergent evolution can further confound the inference of correct evolutionary histories. Given the potential lability of phenotypic characters, molecular dating of insular lineages analyzed in a phylogenetic framework provides a critical tool to test hypotheses of phenotypic divergence since colonization. The Guadalupe junco is the only insular form of the polymorphic dark-eyed junco (Junco hyemalis, and shares eye and plumage color with continental morphs, yet presents an enlarged bill and reduced body size. Here we use variation in mtDNA sequence, morphological traits and song variables to test whether the Guadalupe junco evolved rapidly following a recent colonization by a mainland form of the dark-eyed junco, or instead represents a well-differentiated "cryptic" lineage adapted to the insular environment through long-term isolation, with plumage coloration a result of evolutionary convergence. We found high mtDNA divergence of the island lineage with respect to both continental J. hyemalis and J. phaeonotus, representing a history of isolation of about 600,000 years. The island lineage was also significantly differentiated in morphological and male song variables. Moreover, and contrary to predictions regarding diversity loss on small oceanic islands, we document relatively high levels of both haplotypic and song-unit diversity on Guadalupe Island despite long-term isolation in a very small geographic area. In contrast to prevailing taxonomy, the Guadalupe junco is an old, well-differentiated evolutionary lineage, whose similarity to mainland juncos in plumage and eye color is due to evolutionary convergence. Our findings confirm the role of remote islands

  13. Geothermal Gradient Drilling and Measurements Ascension Island, South Atlantic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Sibbett, B.S.; Nielson, D.L.; Adams, M.C.

    1984-07-01

    This technical report on the Phase II geothermal exploration of Ascension Island documents the data collected during thermal gradient drilling and the subsequent thermal and fluid chemical investigations. It also documents the completion of the Phase II exploration strategy which was proposed at the end of the Phase I--Preliminary Examination of Ascension Island. The thermal gradient drilling resulted in seven holes which range from 206 to 1750 ft (53-533 m) deep, with a cumulative footage of 6563 ft (2000 m). The drilling procedure and the problems encountered during the drilling have been explained in detail to provide information valuable for any subsequent drilling program on the island. In addition, the subsurface geology encountered in the holes has been documented and, where possible, correlated with other holes or the geology mapped on the surface of the island. Temperatures measured in the holes reach a maximum of 130 F (54.4 C) at 1285 ft (391.7 m) in hole GH-6. When the temperatures of all holes are plotted against elevation, the holes can be classed into three distinct groups, those which have no thermal manifestations, those with definite geothermal affinities, and one hole which is intermediate between the other two. From consideration of this information, it is clear that the highest geothermal potential on the island is in the Donkey Flat area extending beneath Middleton Ridge, and in the Cricket Valley area. Because of the greater drilling depths and the remote nature of the Cricket Valley area, it is recommended that future exploration concentrate in the area around Middleton Ridge.

  14. Evaluation of dredged material proposed for ocean disposal from Liberty Island Anchorage, New York

    Energy Technology Data Exchange (ETDEWEB)

    Pinza, M.R.; Barrows, E.S.; Word, J.Q.

    1966-11-01

    Sediment samples were collected from the Liberty Island Anchorage and Military Ocean Terminal in Bayonne, New Jersey (MOTBY), during a survey conducted from June 7 through June 10, 1994. Tests and analyses were conducted on Liberty Island Anchorage sediment core samples according to the manual developed by the U.S. Army Corps of Engineers (USACE) and the U.S. Environmental Protection Agency (EPA), Evaluation of Dredged Material Proposed for Ocean Disposal (Testing Manual), and the regional manual developed by the USACE-New York District (NYD) and EPA Region 11, Guidance for Performing Tests on Dredged Material to be Disposed of in Ocean Waters. The evaluation of proposed dredged material from Liberty Island Anchorage consisted of bulk sediment chemical analyses, chemical analyses of site water and elutriate, and water-column and benthic acute toxicity tests. Individual sediment core samples collected from Liberty Island Anchorage were analyzed for grain size, moisture content, and total organic carbon (TOC). A composite sediment sample, representing the entire area proposed for dredging, was analyzed for bulk density, metals, chlorinated pesticides, polychlorinated-biphenyl (PCB) congeners, polynuclear aromatic hydrocarbons (PAH), 1,4-dichlorobenzene, and dioxin/furan congeners. Site water and elutriate water, prepared from the suspended- particulate phase (SPP) of Liberty Island Anchorage sediment, were analyzed for metals, pesticides, and PCBS.

  15. Phylogeography of a successful aerial disperser: the golden orb spider Nephila on Indian Ocean islands

    Directory of Open Access Journals (Sweden)

    Kuntner Matjaž

    2011-05-01

    Full Text Available Abstract Background The origin and diversification patterns of lineages across the Indian Ocean islands are varied due to the interplay of the complex geographic and geologic island histories, the varying dispersal abilities of biotas, and the proximity to major continental landmasses. Our aim was to reconstruct phylogeographic history of the giant orbweaving spider (Nephila on western Indian Ocean islands (Madagascar, Mayotte, Réunion, Mauritius, Rodrigues, to test its origin and route of dispersal, and to examine the consequences of good dispersal abilities for colonization and diversification, in comparison with related spiders (Nephilengys inhabiting the same islands, and with other organisms known for over water dispersal. We used mitochondrial (COI and nuclear (ITS2 markers to examine phylogenetic and population genetic patterns in Nephila populations and species. We employed Bayesian and parsimony methods to reconstruct phylogenies and haplotype networks, respectively, and calculated genetic distances, fixation indices, and estimated clade ages under a relaxed clock model. Results Our results suggest an African origin of Madagascar Nephila inaurata populations via Cenozoic dispersal, and the colonization of the Mascarene islands from Madagascar. We find evidence of gene flow across Madagascar and Comoros. The Mascarene islands share a common 'ancestral' COI haplotype closely related to those found on Madagascar, but itself absent, or as yet unsampled, from Madagascar. Each island has one or more unique haplotypes related to the ancestral Mascarene haplotype. The Indian Ocean N. inaurata are genetically distinct from the African populations. Conclusions Nephila spiders colonized Madagascar from Africa about 2.5 (0.6-5.3 Ma. Our results are consistent with subsequent, recent and rapid, colonization of all three Mascarene islands. On each island, however, we detected unique haplotypes, consistent with a limited gene flow among the islands

  16. 33 CFR 334.1350 - Pacific Ocean, Island of Oahu, Hawaii; danger zone.

    Science.gov (United States)

    2010-07-01

    ..., Hawaii; danger zone. 334.1350 Section 334.1350 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1350 Pacific Ocean, Island of Oahu, Hawaii; danger zone. (a) The danger zone. Beginning at point of origin at...

  17. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Science.gov (United States)

    2010-07-01

    ... and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The...

  18. The importance of novel and agricultural habitats for the avifauna of an oceanic island

    DEFF Research Database (Denmark)

    Dallimer, Martin; Parnell, Mark; Bicknell, Jake E.

    2012-01-01

    Conservation management can no longer rely on protecting pristine habitats, but must consider the wider landscape. This is especially true on oceanic islands where endemic species are believed to be particularly susceptible to the extinction risks that accompany land conversion. Despite this......, there is a paucity of studies examining how endemic communities on oceanic islands may be distributed across such human-modified habitats. Taking Principe Island in West Africa as a case study, we investigate how avian communities vary across the habitats (primary forest, secondary forest, agricultural areas......) of this globally important centre of endemism. Here, recent policy reforms aimed at poverty alleviation and increased food production are rapidly altering the current land-use mosaic. Across all habitats, 27 bird species were encountered. Survey points in secondary forest and agricultural areas were, on average...

  19. Effects of ocean acidification on the swimming ability, development and biochemical responses of sand smelt larvae

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cátia S.E. [MARE — Marine and Environmental Sciences Centre, ISPA − Instituto Universitário (Portugal); MARE — Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria (Portugal); Novais, Sara C.; Lemos, Marco F.L.; Mendes, Susana [MARE — Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria (Portugal); Oliveira, Ana P. [IPMA — Instituto Português do Mar e da Atmosfera, Algés (Portugal); Gonçalves, Emanuel J. [MARE — Marine and Environmental Sciences Centre, ISPA − Instituto Universitário (Portugal); Faria, Ana M., E-mail: afaria@ispa.pt [MARE — Marine and Environmental Sciences Centre, ISPA − Instituto Universitário (Portugal)

    2016-09-01

    Ocean acidification, recognized as a major threat to marine ecosystems, has developed into one of the fastest growing fields of research in marine sciences. Several studies on fish larval stages point to abnormal behaviours, malformations and increased mortality rates as a result of exposure to increased levels of CO{sub 2}. However, other studies fail to recognize any consequence, suggesting species-specific sensitivity to increased levels of CO{sub 2}, highlighting the need of further research. In this study we investigated the effects of exposure to elevated pCO{sub 2} on behaviour, development, oxidative stress and energy metabolism of sand smelt larvae, Atherina presbyter. Larvae were caught at Arrábida Marine Park (Portugal) and exposed to different pCO{sub 2} levels (control: ~ 600 μatm, pH = 8.03; medium: ~ 1000 μatm, pH = 7.85; high: ~ 1800 μatm, pH = 7.64) up to 15 days, after which critical swimming speed (U{sub crit}), morphometric traits and biochemical biomarkers were determined. Measured biomarkers were related with: 1) oxidative stress — superoxide dismutase and catalase enzyme activities, levels of lipid peroxidation and DNA damage, and levels of superoxide anion production; 2) energy metabolism — total carbohydrate levels, electron transport system activity, lactate dehydrogenase and isocitrate dehydrogenase enzyme activities. Swimming speed was not affected by treatment, but exposure to increasing levels of pCO{sub 2} leads to higher energetic costs and morphometric changes, with larger larvae in high pCO{sub 2} treatment and smaller larvae in medium pCO{sub 2} treatment. The efficient antioxidant response capacity and increase in energetic metabolism only registered at the medium pCO{sub 2} treatment may indicate that at higher pCO{sub 2} levels the capacity of larvae to restore their internal balance can be impaired. Our findings illustrate the need of using multiple approaches to explore the consequences of future pCO{sub 2} levels on

  20. Cultural Voice from an Island Country on the Indian Ocean

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>Located on the southwestern Indian Ocean, the Republic of Seychelles with a beautiful scenery attracts a large number of tourists every year, 60 percent of its national revenues coming from tourism. Besides beautiful natural scenery, its perfect tourist facilities, multiple-ethnic cultures and rich and colourful sea sports are the main attractions for tourists.

  1. Offshore sand-shoal development and evolution of Petit Bois Pass, Mississippi-Alabama Barrier Islands, Mississippi, USA

    Science.gov (United States)

    Flocks, James G.; Kelso, Kyle W.; Twichell, Gregory C.; Buster, Noreen A.; Baehr, John N.; Rosati, Julie D.; Wang, Ping; Roberts, Tiffany M.

    2011-01-01

    Assessment of recently collected geophysical and sediment-core data identifies an extensive shoal field located off Dauphin and Petit Bois Islands. The shoals are the product of Pleistocene fluvial deposition and Holocene marine-transgressive processes, and their position and orientation oblique to the modern shoreline has been stable over the past century. The underlying stratigraphy has also influenced the evolution of the barrier platform and inlets. Buried distributary channels bisect the platform, creating erosion hotspots that breach during intense and repeated storms. Inlet growth inhibits littoral transport, and over time, reduces the down-drift sand supply. These relations demonstrate the role of the antecedent geologic framework on morphologic evolution. This study is part of the USGS Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility Project and the USACE Mississippi Coastal Improvements Program. These projects produced a wealth of information regarding coastal geology, geomorphology, and physical resources; some of the initial results are presented here.

  2. The emergence of volcanic oceanic islands on a slow-moving plate: The example of Madeira Island, NE Atlantic

    Science.gov (United States)

    Ramalho, Ricardo S.; Brum da Silveira, António; Fonseca, Paulo E.; Madeira, José; Cosca, Michael; Cachão, Mário; Fonseca, Maria M.; Prada, Susana N.

    2015-02-01

    The transition from seamount to oceanic island typically involves surtseyan volcanism. However, the geological record at many islands in the NE Atlantic—all located within the slow-moving Nubian plate—does not exhibit evidence for an emergent surtseyan phase but rather an erosive unconformity between the submarine basement and the overlying subaerial shield sequences. This suggests that the transition between seamount and island may frequently occur by a relative fall of sea level through uplift, eustatic changes, or a combination of both, and may not involve summit volcanism. In this study, we explore the consequences for island evolutionary models using Madeira Island (Portugal) as a case study. We have examined the geologic record at Madeira using a combination of detailed fieldwork, biostratigraphy, and 40Ar/39Ar geochronology in order to document the mode, timing, and duration of edifice emergence above sea level. Our study confirms that Madeira's subaerial shield volcano was built upon the eroded remains of an uplifted seamount, with shallow marine sediments found between the two eruptive sequences and presently located at 320-430 m above sea level. This study reveals that Madeira emerged around 7.0-5.6 Ma essentially through an uplift process and before volcanic activity resumed to form the subaerial shield volcano. Basal intrusions are a likely uplift mechanism, and their emplacement is possibly enhanced by the slow motion of the Nubian plate relative to the source of partial melting. Alternating uplift and subsidence episodes suggest that island edifice growth may be governed by competing dominantly volcanic and dominantly intrusive processes.

  3. Natural breeding sites of phlebotomine sand flies (Diptera: Psychodidae) on Marambaia Island, Rio de Janeiro State, Brazil.

    Science.gov (United States)

    Souza, T L; Figueiredo, F B; Almeida, A B; Benigno, C V; Pontes, C S; Souza, M B

    2014-08-01

    Immature phlebotomine sand flies develop in soils with essential and ideal characteristics for their life cycle, such as organic matter, humidity, temperature and low levels of light. Information regarding the potential breeding places of these dipterans is fundamental to understand the epidemiology and ecology of leishmaniasis, in addition to its importance to control them. In the present study, we aimed to find natural breeding sites of sand flies on Marambaia Island with the aid of emergence traps and direct search of immature forms using the flotation technique with saturated sugar solution in organic substrates of the region. Both methods were effective, with a total of 42 specimens of six different species - including some species that participate in the transmission cycle of American Tegumentary Leishmaniasis - collected by the emergence traps, and five immature forms obtained by floatation technique. However, further studies are still necessary, mainly with respect to the ecology and biology of immature sandfly stages, so that control measures focused on breeding sites can produce positive sustainable results in natural environments.

  4. Land use and land cover data changes in Indian Ocean Islands: Case study of Unguja in Zanzibar Island.

    Science.gov (United States)

    Mwalusepo, Sizah; Muli, Eliud; Faki, Asha; Raina, Suresh

    2017-04-01

    Land use and land cover changes will continue to affect resilient human communities and ecosystems as a result of climate change. However, an assessment of land use and land cover changes over time in Indian Ocean Islands is less documented. The land use/cover data changes over 10 years at smaller geographical scale across Unguja Island in Zanzibar were analyzed. Downscaling of the data was obtained from SERVIR through partnership with Kenya-based Regional Centre for Mapping of Resources for Development (RCMRD) database (http://www.servirglobal.net), and clipped down in ArcMap (Version 10.1) to Unguja Island. SERVIR and RCMRD Land Cover Dataset are mainly 30 m multispectral images include Landsat TM and ETM+Multispectral Images. Landscape ecology Statistics tool (LecoS) was used to analysis the land use and land cover changes. The data provide information on the status of the land use and land cover changes along the Unguja Island in Zanzibar. The data is of great significance to the future research on global change.

  5. Iodine environmental availability and human intake in oceanic islands: Azores as a case-study

    Energy Technology Data Exchange (ETDEWEB)

    Linhares, Diana Paula Silva, E-mail: dlinhares@uac.pt [Department of Biology, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); Garcia, Patrícia Ventura, E-mail: patriciag@uac.pt [Department of Biology, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); CE3C, Centre for Ecology, Evolution and Environmental Changes/Azorean Biodiversity Group, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); Almada, Alexandra, E-mail: alexandra_almada@hotmail.com [Department of Biology, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); Ferreira, Teresa, E-mail: teresa.jl.ferreira@azores.gov.pt [Department of Geosciences, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); Queiroz, Gabriela, E-mail: maria.gp.queiroz@azores.gov.pt [Department of Geosciences, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); Cruz, José Virgílio, E-mail: jvc@uac.pt [Department of Geosciences, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); Rodrigues, Armindo dos Santos, E-mail: rodrigues@uac.pt [Department of Biology, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal); CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, 9501-801 Ponta Delgada, Azores (Portugal)

    2015-12-15

    Iodine deficiency is the most common cause of preventable mental impairment. Although several studies have established an association between ocean proximity and iodine environmental availability, recent studies revealed an inadequate iodine intake in the Azorean islands. In this study, we aim to understand the underlying causes of iodine environmental availability in oceanic islands and its association with iodine intake in schoolchildren, using the Azores as case-study. Iodine concentration in soil and grass pasture was measured by INAA and in drinking water by spectrophotometry. Urinary iodine concentration (UIC) in schoolchildren was assessed by ICP-MS in a randomized cross-sectional survey with 315 participants from S. Miguel (study group) and Sta. Maria islands (reference group). A validated diet questionnaire assessing sources of iodine was recorded. The iodine concentration in soils of the reference group was significantly higher than in the study group (58.1 ppm vs. 14.5 ppm, respectively; p = 0.001). The prevalence of schoolchildren with inadequate UIC was significantly higher in the study group than in the reference one (63.0% vs. 37.8%, respectively; p < 0.001). Chronic exposure to low iodine environmental availability was significantly associated with the exacerbation in iodine deficiency, with a risk 4.94 times higher in the study group. The differences observed in the studied islands are related with each island geomorphology (soil properties and orography) and climate, which can promote or inhibit iodine environmental availability, contributing distinctively to iodine bioavailability and human intake. These findings draw attention to an urgent need for a full investigation of Azores iodine status to apply evidence-based recommendations for iodine supplementation. - Highlights: • Iodine intake in schoolchildren differs between islands of the Azorean archipelago. • Island geomorphology and climate modulate iodine environmental availability. • In

  6. Large eruption-triggered ocean-island landslide at Tenerife

    DEFF Research Database (Denmark)

    Harris, P; Branney, M; Storey, Michael

    2011-01-01

    An extensive debris-avalanche deposit has been discovered on Cañadas volcano, Tenerife (Canary Islands). The onshore component of the 733 ± 3 ka Abona landslide deposit exposes classic block facies and mixed facies across 90 km2. Three lines of evidence together show that the avalanche was trigge......, and created a major breach that affected the passage of destructive pyroclastic density currents on Tenerife for 0.5 m.y., showing that landslides can have enduring consequences for pyroclastic dispersal and hazards....

  7. Barrier island breach evolution: Alongshore transport and bay-ocean pressure gradient interactions

    Science.gov (United States)

    Safak, Ilgar; Warner, John C.; List, Jeffrey H.

    2016-12-01

    Physical processes controlling repeated openings and closures of a barrier island breach between a bay and the open ocean are studied using aerial photographs and atmospheric and hydrodynamic observations. The breach site is located on Pea Island along the Outer Banks, separating Pamlico Sound from the Atlantic Ocean. Wind direction was a major control on the pressure gradients between the bay and the ocean to drive flows that initiate or maintain the breach opening. Alongshore sediment flux was found to be a major contributor to breach closure. During the analysis period from 2011 to 2016, three hurricanes had major impacts on the breach. First, Hurricane Irene opened the breach with wind-driven flow from bay to ocean in August 2011. Hurricane Sandy in October 2012 quadrupled the channel width from pressure gradient flows due to water levels that were first higher on the ocean side and then higher on the bay side. The breach closed sometime in Spring 2013, most likely due to an event associated with strong alongshore sediment flux but minimal ocean-bay pressure gradients. Then, in July 2014, Hurricane Arthur briefly opened the breach again from the bay side, in a similar fashion to Irene. In summary, opening and closure of breaches are shown to follow a dynamic and episodic balance between along-channel pressure gradient driven flows and alongshore sediment fluxes.

  8. Exploring "The Island": Mapping the Shifting Sands in the Landscape of English Classroom Culture and Pedagogy

    Science.gov (United States)

    Anderson, Gill

    2013-01-01

    I begin with an account of my own observation of an English lesson taught by one of my student teachers using a teaching resource, "The Island," that I used myself as a new teacher more than 20 years ago and of my own responses on finding it transformed by two decades of change in educational policy and practice. It has become almost a…

  9. Pillow basalts of the Angayucham terrane: Oceanic plateau and island crust accreted to the Brooks Range

    Science.gov (United States)

    Pallister, John S.; Budahn, James R.; Murchey, Benita L.

    1989-11-01

    The Angayucham Mountains (north margin of the Yukon-Koyukuk province) are made up of an imbricate stack of four to eight east-west trending, steeply dipping, fault slabs composed of Paleozoic (Devonian to Mississippean), Middle to Late Triassic, and Early Jurassic oceanic upper crustal rocks (pillow basalt, subordinate diabase, basaltic tuff, and radiolarian chert). Field relations and geochemical characteristics of the basaltic rocks suggest that the fault slabs were derived from an oceanic plateau or island setting and were emplaced onto the Brooks Range continental margin. The basalts are variably metamorphosed to prehnite-pumpellyite and low-greenschist facies. Major element analyses suggest that many are hypersthene-normative olivine tholeiites. Classification based on immobile trace elements confirms the tholeiitic character of most of the basalts but suggests that some had primary compositions transitional to alkali basalt. Although field and petrographic features of the basalts are similar, trace element characteristics allow definition of geographically distinct suites. A central outcrop belt along the crest of the mountains is made up of basalt with relatively flat rare earth element (REE) patterns. This belt is flanked to the north and south by LREE (light rare earth element)-enriched basalts. Radiolarian and conodont ages from interpillow and interlayered chert and limestone indicate that the central belt of basalts is Triassic in age, the southern belt is Jurassic in age, and the northern belt contains a mixture of Paleozoic and Mesozoic ages. Data for most of the basalts cluster in the "within-plate basalt" fields of trace element discriminant diagrams; none have trace-element characteristics of island arc basalt. The Triassic and Jurassic basalts are geochemically most akin to modern oceanic plateau and island basalts. Field evidence also favors an oceanic plateau or island setting. The great composite thickness of pillow basalt probably resulted

  10. Seismic structure of the lithosphere and upper mantle beneath the ocean islands near mid-oceanic ridges

    Science.gov (United States)

    Haldar, C.; Kumar, P.; Kumar, M. Ravi

    2014-05-01

    Deciphering the seismic character of the young lithosphere near mid-oceanic ridges (MORs) is a challenging endeavor. In this study, we determine the seismic structure of the oceanic plate near the MORs using the P-to-S conversions isolated from quality data recorded at five broadband seismological stations situated on ocean islands in their vicinity. Estimates of the crustal and lithospheric thickness values from waveform inversion of the P-receiver function stacks at individual stations reveal that the Moho depth varies between ~ 10 ± 1 km and ~ 20 ± 1 km with the depths of the lithosphere-asthenosphere boundary (LAB) varying between ~ 40 ± 4 and ~ 65 ± 7 km. We found evidence for an additional low-velocity layer below the expected LAB depths at stations on Ascension, São Jorge and Easter islands. The layer probably relates to the presence of a hot spot corresponding to a magma chamber. Further, thinning of the upper mantle transition zone suggests a hotter mantle transition zone due to the possible presence of plumes in the mantle beneath the stations.

  11. Deep intrusions, lateral magma transport and related uplift at ocean island volcanoes

    Science.gov (United States)

    Klügel, Andreas; Longpré, Marc-Antoine; García-Cañada, Laura; Stix, John

    2015-12-01

    Oceanic intraplate volcanoes grow by accumulation of erupted material as well as by coeval or discrete magmatic intrusions. Dykes and other intrusive bodies within volcanic edifices are comparatively well studied, but intrusive processes deep beneath the volcanoes remain elusive. Although there is geological evidence for deep magmatic intrusions contributing to volcano growth through uplift, this has rarely been demonstrated by real-time monitoring. Here we use geophysical and petrological data from El Hierro, Canary Islands, to show that intrusions from the mantle and subhorizontal transport of magma within the oceanic crust result in rapid endogenous island growth. Seismicity and ground deformation associated with a submarine eruption in 2011-2012 reveal deep subhorizontal intrusive sheets (sills), which have caused island-scale uplift of tens of centimetres. The pre-eruptive intrusions migrated 15-20 km laterally within the lower oceanic crust, opening pathways that were subsequently used by the erupted magmas to ascend from the mantle to the surface. During six post-eruptive episodes between 2012 and 2014, further sill intrusions into the lower crust and upper mantle have caused magma to migrate up to 20 km laterally, resulting in magma accumulation exceeding that of the pre-eruptive phase. A comparison of geobarometric data for the 2011-2012 El Hierro eruption with data for other Atlantic intraplate volcanoes shows similar bimodal pressure distributions, suggesting that eruptive phases are commonly accompanied by deep intrusions of sills and lateral magma transport. These processes add significant material to the oceanic crust, cause uplift, and are thus fundamentally important for the growth and evolution of volcanic islands. We suggest that the development of such a magma accumulation zone in the lower oceanic crust begins early during volcano evolution, and is a consequence of increasing size and complexity of the mantle reservoir system, and potentially

  12. Shallow seismic imaging of flank collapse structures in oceanic island volcanoes: Application to the Western Canary Islands

    Science.gov (United States)

    Sanchez, L.; González, P.; Tiampo, K. F.

    2013-12-01

    Volcanic flank collapse counts among the many hazards associated with volcanic activity. This type of event involves the mobilization of large volumes, producing debris avalanches. It affects mostly oceanic island volcanoes, involving the potential for tsunami occurrence. Geophysical imaging can illuminate subvolcanic features such as volcano-tectonic structures, magmatic plumbing systems or differences in rock type. The most commonly used geophysical methods are gravity, electromagnetics and seismics. In particular, seismic measurements quantify anomalies in seismic waves propagation velocities and can be used to obtain information on the subsurface arrangement of different materials. In the Western Canary Islands, the Cumbre Vieja volcano in La Palma (Canary Islands) has been proposed to be near the collapse stage. Previous geophysical studies that have been carried out on the flank of the volcano comprise gravity and electromagnetic methods. These types of surveys gather information on the deep structures of the volcano (1-2 km). In this project, we complement previous studies by using seismic methods to investigate the near-surface seismic structure of the Cumbre Vieja fault system (La Palma Island) and the structure of the well-developed San Andres fault system (El Hierro Island). We aim to compare the Cumbre Vieja and San Andres fault systems to infer the degree of maturity of collapse structures. We carried out reflection and refraction seismic surveys in order to image approximately the first 10 meters of the subsurface. We used 24 low frequency (4,5 Hz) geophones as receivers and a sledge hammer as the seismic source. The survey lines were located across visible parts of the fault systems at the Cumbre Vieja volcano and the San Andres fault in El Hierro. Here, we present the survey setup and results from the preliminary analysis of the data.

  13. Effects of Sand Dune and Vegetation in the Coastal Area of Sri Lanka at the Indian Ocean Tsunami

    Science.gov (United States)

    Tanaka, Norio; Sasaki, Yasushi; Mowjood, M. I. M.

    This study explored the effects of coastal vegetation and sand dune on tsunami protection based on field observations carried out after the Indian Ocean tsunami on December 26, 2004. The representative vegetation was classified into six types according to their habitat and the stand structures of the trees. The impact of vegetation structure on drag forces was analyzed using the observed characteristics of the tree species. The drag coefficient, including the vertical stand structures of the trees, Cd-all, and the vegetation thickness in a unit area, dNu (d: reference diameter of trees, Nu: number of trees per unit area), varied greatly with the species classification. Based on the field survey and data analysis, Rhizophora apiculata and Rhizophora mucronata (Rhizophora apiculata-type), kinds of mangroves, and Pandanus odoratissimus, representative tree that grows in beach sand, were found to be especially effective in providing protection from tsunami-damage due to their complex aerial root structures. The breaking moment of the trees was investigated through a pulling test for the representative trees. The threshold value for breaking moment was compared to the drag-force moment acting on the trees located at the tsunami-damaged site. The breaking moment equation represents well the limitation of the representative species with the tsunami height. It arrives at a hypothesis about which species could better withstand the effects of a tsunami wave. Sand dune and lagoon is a typical landscape in most part of the coastal zone of Sri Lanka. The combination of the sand dune followed by vegetation toward landside played an important role in retarding tsunami. Two layers of forest in the vertical direction with P. odoratissimus and Casuarina equisetifolia and a horizontal forest structure of small and large diameter trees were also important for increasing drag, trapping floating objects, broken branches, houses, and people. These information should be considered in

  14. Banaras in the Indian Ocean: Circulating, Connecting and Creolizing Island Stories

    Directory of Open Access Journals (Sweden)

    Srilata Ravi

    2012-06-01

    Full Text Available What links Bernardin de Saint Pierre’s 1788 novel about Isle de France, Paul et Virginie, with V.S. Naipaul’s 1972 piece, An overcrowded Barracoon? What is common to Joseph Conrad’s 1910 novella, A Smile of Fortune, and tourist brochures of La Grande Baie? What brings together the story of the ruins of Babylon and the Ghats of the Ganges? Actually, these seemingly disjointed narratives make up a vast library of inter-connecting Indian Ocean island stories. In this study I will use the image of ‘Banaras’ as the locus of an inter-textual reading exercise connecting the literary spaces of Mauritian writer and filmmaker Barlen Pyamootoo with other stories like those mentioned above. Pyamootoo’s literary universe reveals to us the dynamic, multilayered and polyphonic nature of Indian Ocean island cultures.

  15. Chemical composition of a saline lake on Enderbury Island, Phoenix Island Group, Pacific Ocean

    Science.gov (United States)

    Gulbrandsen, Robert A.; Brown, David W.

    1973-01-01

    Ion activity products for the dissolution of calcite, aragonite, gypsum, monetite, brushite, dolomite, magnesite, hydroxyapatite, and fluorapatite were calculated for a South Pacific guano island brine with an ionic strength of 6.4. Environmental conditions for the brine at the time of analysis and of sampling indicated saturation with respect to calcite, aragonite, gypsum, hydroxyapatite and fluorapatite; a comparison of the ion activity products and equilibrium constants indicated saturation or supersaturation with respect to most minerals found in lake sediments or elsewhere on the island. The results suggest that chemical thermodynamic calculations for brines may have some usefulness despite the many assumptions and estimations that must be made.

  16. Plant invasion and speciation along elevational gradients on the oceanic island La Palma, Canary Islands

    DEFF Research Database (Denmark)

    Steinbauer, Manuel; Irl, Severin David Howard; González-Mancebo, Juana Maria

    2017-01-01

    systematically along three elevational gradients covering large parts of the climatic range of La Palma, Canary Islands. Results: Species richness was negatively correlated with elevation, while the percentage of Canary endemic species showed a positive relationship. However, the percentage of Canary-Madeira...... from high elevations indicating directional ecological filtering. Increasing ecological isolation with elevation drives diversification and thus increased percentages of Canary endemics. The best preserved eastern transect, including mature laurel forests is an exception. The high percentage of Canary-Madeira...

  17. Submersible Data (Dive Waypoints) for Islands in the Stream 2002 - Pharmaceutical Discovery, Vision, and Bioluminescence - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data and information collected by the submersible Johnson Sea-Link II at waypoints along its track during one dive of the 2002 "Islands in the Stream -...

  18. Ship track for Islands in the Stream 2002 - Pharmaceutical Discovery, Vision, and Bioluminescence - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ship track of the R/V Seward Johnson during the 2002 "Islands in the Stream - Pharmaceutical Discovery, Vision, and Bioluminescence" expedition sponsored by the...

  19. Ship Sensor Observations for Islands in the Stream 2002 - Pharmaceutical Discovery, Vision, and Bioluminescence - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly measurements made by selected ship sensors on the R/V Seward Johnson during the 2002 "Islands in the Stream - Pharmaceutical Discovery, Vision, and...

  20. Submersible Data (Dive Waypoints) for Islands in the Stream 2002 - Deep Reef Habitat - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data and information collected by the submersible Johnson Sea-Link II at waypoints along its track during one dive of the 2002 "Islands in the Stream - Deep Reef...

  1. Reef fish structure and distribution in a south-western Atlantic Ocean tropical island.

    Science.gov (United States)

    Pinheiro, H T; Ferreira, C E L; Joyeux, J-C; Santos, R G; Horta, P A

    2011-12-01

    The community structure of the reef fish fauna of Trindade Island, a volcanic oceanic island located 1160 km off the coast of Brazil, is described based on intensive visual censuses. Seventy-six species were encountered in 252 censuses, with mean ± S.E. of 99 ± 3 individuals and 15.7 ± 0.3 species 40 m(-2) transect. The average fish biomass, calculated from length-class estimation, was 22.1 kg 40 m(-2) transect. The species contributing most to biomass were, in decreasing order, Melichthys niger, Cephalopholis fulva, Kyphosus spp., Holocentrus adscensionis, Sparisoma amplum, Sparisoma axillare, Acanthurus bahianus and Epinephelus adscensionis. Carnivorous fishes were the largest trophic group in terms of biomass, followed by omnivores and roving herbivores. The two predominant types of reef habitat, fringing reefs built by coralline algae and rocky reefs made of volcanic boulders, showed significant differences in the biomass and the abundance of the trophic guilds. Within each habitat type, significant differences in species richness, density and biomass were detected among crest, slope and interface zones. Although similar in overall species composition to coastal reefs in Brazil, the fish fauna of Trindade Island shares certain characteristics, such as a high abundance of planktivores, with other Brazilian oceanic islands. Despite comparatively high fish biomass, including the macro-carnivorous species habitually targeted by fisheries, signs of overfishing were evident. These findings highlight the urgency for a conservation initiative for this isolated, unique and vulnerable reef system.

  2. Depositional model of Early Permian reef-island ocean inEastern Kunlun

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Many fusulinid fossils have been found in thin- to middle-bedded limestones which aredistributed between the Early Permian limestone hills and formerly considered as Early Triassic.The fusulinid fossils, identified as Neoshwagerina sp., Verbeekina sp. and Schwagerina sp., canalso be found in massive limestone hills. At the same time, Early Permian radiolarian chert of deepbasin facies was discovered in Animaqing. All the above show that the massive limestone hills,thin- to middle-bedded limestones and radiolarian chert belong to syndeposits in Early Permianocean. The sediments in the study area can roughly be divided into three types: shallow facies,basin facies and transitional facies. The carbonate buildup can be subdivided into massive bioclas-tic limestone and reef framestone. Basin facies contains thin- or middle-bedded limestone, abyssalred mudstone or ooze, blue-green mudstone and radiolarian chert. Transitional facies includes reeftalus and platformal skirt facies. The Early Permian ocean in Eastern Kunlun is recognized as akind of reef-island ocean environment according to distribution and composition of different facies.The reef-island ocean in Eastern Kunlun is characterized by reef islands (or carbonate buildups)alternating with basins, complicated sea-floor topography, sharp facial change and well-developedreefs

  3. Lutzomyia sand fly diversity and rates of infection by Wolbachia and an exotic Leishmania species on Barro Colorado Island, Panama.

    Directory of Open Access Journals (Sweden)

    Jorge Azpurua

    Full Text Available BACKGROUND: Sand flies (Diptera, Psychodidae, Phlebotominae in the genus Lutzomyia are the predominant vectors of the protozoan disease leishmaniasis in the New World. Within the watershed of the Panama Canal, the cutaneous form of leishmaniasis is a continuous health threat for residents, tourists and members of an international research community. Here we report the results of screening a tropical forest assemblage of sand fly species for infection by both Leishmania and a microbe that can potentially serve in vector population control, the cytoplasmically transmitted rickettsia, Wolbachia pipientis. Knowing accurately which Lutzomyia species are present, what their evolutionary relationships are, and how they are infected by strains of both Leishmania and Wolbachia is of critical value for building strategies to mitigate the impact of this disease in humans. METHODOLOGY AND FINDINGS: We collected, sorted and then used DNA sequences to determine the diversity and probable phylogenetic relationships of the Phlebotominae occurring in the understory of Barro Colorado Island in the Republic of Panama. Sequence from CO1, the DNA barcoding gene, supported 18 morphology-based species determinations while revealing the presence of two possible "cryptic" species, one (Lu. sp. nr vespertilionis within the Vespertilionis group, the other (Lu. gomezi within the Lutzomyia-cruciata series. Using ITS-1 and "minicircle" primers we detected Leishmania DNA in 43.3% of Lu. trapidoi, 26.3% of Lu. gomezi individuals and in 0% of the other 18 sand fly species. Identical ITS-1 sequence was obtained from the Leishmania infecting Lu. trapidoi and Lu. gomezi, sequence which was 93% similar to Leishmania (viannia naiffi in GenBank, a species previously unknown in Panama, but recognized as a type of cutaneous leishmaniasis vectored broadly across northern and central South America. Distinct strains of the intracellular bacterium Wolbachia were detected in three of 20

  4. 33 CFR 334.960 - Pacific Ocean, San Clemente Island, Calif.; naval danger zone off West Cove.

    Science.gov (United States)

    2010-07-01

    ... Island, Calif.; naval danger zone off West Cove. 334.960 Section 334.960 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.960 Pacific Ocean, San Clemente Island, Calif.; naval danger zone off West Cove. (a)...

  5. 33 CFR 334.961 - Pacific Ocean, San Clemente Island, California, naval danger zone off the northwest shore.

    Science.gov (United States)

    2010-07-01

    ... Island, California, naval danger zone off the northwest shore. 334.961 Section 334.961 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.961 Pacific Ocean, San Clemente Island, California, naval danger zone...

  6. Groundwater flow in a relatively old oceanic volcanic island: The Betancuria area, Fuerteventura Island, Canary Islands, Spain

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Christian, E-mail: cherrera@ucn.cl [Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Custodio, Emilio [Department of Geo-Engineering, Technical University of Catalonia (UPC), Barcelona (Spain)

    2014-10-15

    The island of Fuerteventura is the oldest of the Canary Islands' volcanic archipelago. It is constituted by volcanic submarine and subaerial activity and intrusive Miocene events, with some residual later volcanism and Quaternary volcanic deposits that have favored groundwater recharge. The climate is arid, with an average rainfall that barely attains 60 mm/year in the coast and up to 200 mm/year in the highlands. The aquifer recharge is small but significant; it is brackish due to large airborne atmospheric salinity, between 7 and 15 g m{sup −2} year{sup −1} of chloride deposition, and high evapo-concentration in the soil. The average recharge is estimated to be less than about 5 mm/year at low altitude and up to 10 mm/year in the highlands, and up to 20 mm/year associated to recent lava fields. Hydrochemical and water isotopic studies, supported by water table data and well and borehole descriptions, contribute a preliminary conceptual model of groundwater flow and water origin in the Betancuria area, the central area of the island. In general, water from springs and shallow wells tends to be naturally brackish and of recent origin. Deep saline groundwater is found and is explained as remnants of very old marine water trapped in isolated features in the very low permeability intrusive rocks. Preliminary radiocarbon dating indicates that this deep groundwater has an apparent age of less than 5000 years BP but it is the result of mixing recent water recharge with very old deep groundwater. Most of the groundwater flow occurs through the old raised volcanic shield of submarine and subaerial formations and later Miocene subaerial basalts. Groundwater transit time through the unsaturated zone is of a few decades, which allows the consideration of long-term quasi-steady state recharge. Transit times are up to a few centuries through the saturated old volcanics and up to several millennia in the intrusive formations, where isolated pockets of very old water may

  7. Modeling the erosion of tropical volcanic ocean islands : The Tahiti island case (French Polynesia)

    Science.gov (United States)

    Ye, F.; Sichoix, L.; Barriot, J.; Dumas, P.

    2009-12-01

    In this study, we are interested in modeling the erosion of the Tahiti island, with two main objectives: risk assessment (erodibility of terrains with rainfall, catastrophic runoffs) and estimation of subsidence rate. The Tahiti island created around 1.4 Myears ago by an intraplate hotspot (aerial radiometric dating), is divided into two geological units: the main island Tahiti-Nui to northwest (end of volcanism 200,000 years ago) and the subsidiary Tahiti-Iti to the southeast (end of volcanism 380,000 years ago). It is now volcanically inactive and is deeply dissected by erosion. Tahiti Nui is around 30 km in diameter, and Tahiti Iti around 15 km. Both are linked through the isthmus of Taravao. The highest elevation is 2241 m. The two sub-islands are basaltic edifices, with an overwhelming presence of oxisols (down to tens of meters in some places). Slopes can be divided into three classes: 15° for the global slope of the shield volcanoes, 47° for the incision valleys and 2° for the seashore rim. Rainfalls range from 8,000 mm/year on the East side of Tahiti (trade winds) to 2,000 mm/year on the West side, the humid season of a year is summer. This study is conducted to validate the Unit Stream Power Erosion and Deposition (USPED) model, an enrichment to the Universal Soil Loss Equation (USLE) to calculate average annual soil loss per unit land area resulting from rill and sheet erosion. The USPED model differs from other USLE models on how it handles the influence of topography on the erosion process, because USLE consider erosion only along the flow line without the influence of flow convergence/divergence. As the result, the USPED model predicts both erosion and deposition, while most other USLE-based models are limited to predictions of erosion only. The USLE, USPED equation can be written as A=R*K*LS*C*P where A is the soil loss, R the rainfall-runoff erosivity factor, K a soil erodibility factor, L a slope-length factor, S a slope steepness factor, C a

  8. Nitrogen Loads in Groundwater Entering Back Bays and Ocean from Fire Island National Seashore, Long Island, New York

    Science.gov (United States)

    Schubert, Christopher E.; deVries, M. Peter; Finch, Anne J.

    2010-01-01

    Fire Island is a barrier island that lies south of central Long Island, N.Y. It is about 60 km (37 mi) long and 0.5 km (1/4 mi) wide and is bounded by the Great South Bay, Narrow Bay, and Moriches Bay estuaries to the north; by the Atlantic Ocean to the south; by Fire Island Inlet to the west; and by Moriches Inlet to the east (fig. 1). Fire Island National Seashore (FIIS) encompasses a 42-km (26-mi) length of Fire Island that is bordered by Robert Moses State Park to the west and Smith Point County Park to the east (fig. 2). Interspersed throughout FIIS are 17 residential beach communities that together contain about 4,100 homes. The barrier island's summer population increases 50-fold through the arrival of summer residents and vacationers. The National Park Service (NPS) has established several facilities on the island to accommodate visitors to FIIS. About 2.2 million people visit at least one of the 17 communities and (or) Smith Point County Park, the waterways surrounding Fire Island, or a FIIS facility annually (National Park Service, 2007). Combined visitation on a peak-season weekend day can be as high as 100,000 (National Park Service, 2002). Most homes and businesses in the 17 barrier-island communities discharge untreated wastewater directly to the shallow (water-table) aquifer through private septic systems and cesspools; the NPS facilities discharge wastewater to this aquifer through leach fields and cesspools. (The community of Ocean Beach (fig. 2) has a treatment plant that discharges to tidewater.) Contaminants in sewage entering the shallow groundwater move through the flow system and are ultimately discharged to adjacent marine surface waters, where they can pose a threat to coastal habitats. A contaminant of major concern is nitrogen, which is derived from fertilizers and human waste. The continuous inflow of nitrogen to surface-water bodies can lead to increased production of phytoplankton and macroalgae, which in turn can cause oxygen

  9. Description and epizootiology of Babesia poelea n. sp. in brown boobies (Sula leucogaster (Boddaert)) on Sand Island, Johnston Atoll, Central Pacific

    Science.gov (United States)

    Work, T.M.; Rameyer, R.A.

    1997-01-01

    We describe a new species of piroplasm from brown boobies (Sula leucogaster) on Sand Island, Johnston Atoll National Wildlife Refuge, central Pacific. Mean parasitemia in adults and chicks was less than 1%, with the parasitemia in chicks significantly greater than in adults. There was no significant relation between the age of chicks and the degree of parasitemia. Parasitized red cells and red cell nuclei were significantly smaller than those of unparasitized cells, and infected birds appeared clinically normal. Prevalence of the parasite in chicks (54%) was significantly greater than in adults (13%), and the geographic distribution of parasitized chicks was skewed toward the eastern end of Sand Island. On the basis of morphologic characteristics, we named it Babesia poelea. The specific name is a concatenation of the Hawaiian names for dark (po'ele) and booby ('a). This is the second documentation of an endemic avian hemoparasite in seabirds from the central Pacific.

  10. Depleted and metasomatized oceanic lithosphere beneath La Palma, Canary Islands

    Science.gov (United States)

    Janisch, Astrid; Ntaflos, Theodoros

    2017-04-01

    Due to the inaccessibility of Earth's interior, xenoliths became the best possibility to study the chemical composition of the earth mantle as well as its various processes. Three samples out of the sample suite of mantle peridotites from San Antonio Volcano on La Palma, Canary Islands, have been chosen to illustrate three examples of diverse mantle metasomatic events. The first sample, a pyroxene-hornblende-peridotite, was influenced by an alkali-rich, silicic-hydrous undersaturated melt and/or fluid forming a conspicuous cross-cutting amphibole-apatite-dyke with several veins percolating through the rock. Forsterite content in olivine varies between 82.5 - 85.5 and 86.0 - 89.0, suggesting at least two different occurrences of metasomatic overprint. Clinopyroxenes are mostly found in association with amphibole and in textural equilibrium hinting that both minerals may have grown together, while orthopyroxene have only been found as remnant inclusions in olivine. These clinopyroxenes are Cr-Diopsides with En43.40-50.97-Wo43.99-48.64-Fs4.30-8.22 and Mg# between 85.54 and 92.36. Secondary clinopyroxenes are Ti-Augites with En39.86-46.81-Wo46.65-51.98-Fs5.86-8.72 and Mg# of 82.44 - 89.09. The second sample, a sp-dunite, is characterized by haüyne-bearing melt veins which clearly indicate host-basalt infiltration. The haüyne is always in contact with amphibole, spinel and clinopyroxene denoting that they have been formed at the same time because there is no evidence for reaction among these phases. The melt infiltration apparently took place prior to xenolith entrainment in the host basalt. Primary olivine has Fo content of 89.57 - 89.67 with NiO ranging from 0.32 - 0.334, in contrast Fo content in secondary olivine varies from 89.05 - 90.86 and NiO fluctuates between 0.24 - 0.31. Cr-Diopside compositions are in range of En41.63-47.05-Wo47.83-51-90-Fs4.93-6.64 and Mg# between 86.48 - 90.50. The third sample is also a sp-dunite and marked by a network of phlogopite

  11. Genetic consequences of cladogenetic vs. anagenetic speciation in endemic plants of oceanic islands.

    Science.gov (United States)

    Takayama, Koji; López-Sepúlveda, Patricio; 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

    2015-08-26

    Adaptive radiation is a common mode of speciation among plants endemic to oceanic islands. This pattern is one of cladogenesis, or splitting of the founder population, into diverse lineages in divergent habitats. In contrast, endemic species have also evolved primarily by simple transformations from progenitors in source regions. This is anagenesis, whereby the founding population changes genetically and morphologically over time primarily through mutation and recombination. Gene flow among populations is maintained in a homogeneous environment with no splitting events. Genetic consequences of these modes of speciation have been examined in the Juan Fernández Archipelago, which contains two principal islands of differing geological ages. This article summarizes population genetic results (nearly 4000 analyses) from examination of 15 endemic species, involving 1716 and 1870 individuals in 162 and 163 populations (with amplified fragment length polymorphisms and simple sequence repeats, respectively) in the following genera: Drimys (Winteraceae), Myrceugenia (Myrtaceae), Rhaphithamnus (Verbenaceae), Robinsonia (Asteraceae, Senecioneae) and Erigeron (Asteraceae, Astereae). The results indicate that species originating anagenetically show high levels of genetic variation within the island population and no geographic genetic partitioning. This contrasts with cladogenetic species that show less genetic diversity within and among populations. Species that have been derived anagenetically on the younger island (1-2 Ma) contain less genetic variation than those that have anagenetically speciated on the older island (4 Ma). Genetic distinctness among cladogenetically derived species on the older island is greater than among similarly derived species on the younger island. An important point is that the total genetic variation within each genus analysed is comparable, regardless of whether adaptive divergence occurs. Published by Oxford University Press on behalf of the

  12. Groundwater flow in a relatively old oceanic volcanic island: the Betancuria area, Fuerteventura Island, Canary Islands, Spain.

    Science.gov (United States)

    Herrera, Christian; Custodio, Emilio

    2014-10-15

    The island of Fuerteventura is the oldest of the Canary Islands' volcanic archipelago. It is constituted by volcanic submarine and subaerial activity and intrusive Miocene events, with some residual later volcanism and Quaternary volcanic deposits that have favored groundwater recharge. The climate is arid, with an average rainfall that barely attains 60 mm/year in the coast and up to 200 mm/year in the highlands. The aquifer recharge is small but significant; it is brackish due to large airborne atmospheric salinity, between 7 and 15 gm(-2)year(-1) of chloride deposition, and high evapo-concentration in the soil. The average recharge is estimated to be less than about 5 mm/year at low altitude and up to 10 mm/year in the highlands, and up to 20 mm/year associated to recent lava fields. Hydrochemical and water isotopic studies, supported by water table data and well and borehole descriptions, contribute a preliminary conceptual model of groundwater flow and water origin in the Betancuria area, the central area of the island. In general, water from springs and shallow wells tends to be naturally brackish and of recent origin. Deep saline groundwater is found and is explained as remnants of very old marine water trapped in isolated features in the very low permeability intrusive rocks. Preliminary radiocarbon dating indicates that this deep groundwater has an apparent age of less than 5000 years BP but it is the result of mixing recent water recharge with very old deep groundwater. Most of the groundwater flow occurs through the old raised volcanic shield of submarine and subaerial formations and later Miocene subaerial basalts. Groundwater transit time through the unsaturated zone is of a few decades, which allows the consideration of long-term quasi-steady state recharge. Transit times are up to a few centuries through the saturated old volcanics and up to several millennia in the intrusive formations, where isolated pockets of very old water may exist.

  13. Chromian spinel-rich black sands from eastern shoreline of Andaman Island, India: Implication for source characteristics

    Indian Academy of Sciences (India)

    Koyel Bhatta; Biswajit Ghosh

    2014-08-01

    Black sands rich in chromian spinel commonly occur in pockets along the eastern shoreline of Andaman Island where various types of peridotites and volcanics belonging to the Andaman ophiolite suite are exposed in close vicinity. The chemistry of these detrital chromian spinels has been extensively used here in identifying the source rocks vis-à-vis deciphering the source characteristics. The composition of the chromian spinels (Cr#: 0.20–0.88, Mg#: 0.26–0.77, Al2O3: 5.04–48.21 wt.%, TiO2: up to 1.39 wt.% and Fe2+/Fe3+: 1.73–9.12) varies widely signifying multiple sources, of which mantle peridotites and volcanic rocks are relevant in an ophiolitic terrain. The volcanic chromian spinels are relatively fresh, commonly euhedral, sometimes with compositional variations, and contain inclusions in contrast to the mantle peridotitic chromian spinels which are rounded, extensively fractured, and altered. We used a number of geochemical bivariate plots in order to know the provenance protoliths. The volcanic chromian spinels show geochemical characters of MORB, related to spreading centers (either MOR or back-arc) and also boninites/arc-tholeiites, related to active subduction. On the other hand, the peridotitic spinels indicate partially depleted lherzolite and depleted harzburgite source of the ophiolite suite.

  14. Transferring and implementing the general dynamic model of oceanic island biogeography at the scale of island fragments: the role of geological age and topography in plant diversification in the Canaries

    DEFF Research Database (Denmark)

    Otto, Rüdiger; Whittaker, Robert J.; von Gaisberg, Markus;

    2016-01-01

    Aim The general dynamic model (GDM) of oceanic island biogeography integrates rates of immigration, speciation and extinction in relation to a humped trajectory of island area and topographic complexity through time, based on a simplified island ontogeny. In practice, many islands have more compl...

  15. New data regarding distribution of cattle ticks in the south-western Indian Ocean islands.

    Science.gov (United States)

    Stachurski, Frédéric; Tortosa, Pablo; Rahajarison, Patrick; Jacquet, Stéphanie; Yssouf, Amina; Huber, Karine

    2013-09-09

    Recent studies have produced new insight into the origin and distribution of some cattle ticks in the south-western Indian Ocean islands. Rhipicephalus appendiculatus, introduced from Tanzania in 2002, is now well established on Grande Comore but has not yet reached the other islands of the archipelago (Mohéli, Anjouan and Mayotte). Only one of the two clades identified in Africa has settled so far. Amblyomma variegatum, which was not supposed to be able to persist in the Antananarivo region (1300 m) nor in other Malagasy regions of high altitude without regular introductions of ticks by infested cattle, is now endemic as a general rule up to 1600 m although other regions of lower altitude (1400 m) are still free of the tick. This species remains confined in a small area of the west coast on La Reunion Island. On the contrary, Hyalomma dromedarii could not settle on Madagascar where it was introduced in 2008 and Rhipicephalus evertsi evertsi is not yet present in Grande Comore despite regular introductions by infested cattle from Tanzania. A phylogeographic approach has been carried out at an intra-specific level for A. variegatum. This study has led to the identification of two main lineages, one covering all species distribution and one restricted to East Africa and the Indian Ocean area. These two lineages are in sympatry in Madagascar where a high genetic diversity has been described, whereas a lower genetic diversity is observed on other islands. These results seem to agree with the historical data concerning the introduction of the tick in the Indian Ocean area.

  16. Volcanism, Iron, and Phytoplankton in the Heard and McDonald Islands Region, Southern Indian Ocean

    Science.gov (United States)

    Coffin, M. F.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Trull, T. W.; Heobi in2016 v01 Shipboard Party, T.

    2016-12-01

    Phytoplankton supply approximately half of the oxygen in Earth's atmosphere, and iron supply limits the growth of phytoplankton in the anemic Southern Ocean. Situated entirely within the Indian Ocean sector of the Southern Ocean are Australia's only active subaerial volcanoes, Heard and McDonald islands (HIMI) on the central Kerguelen Plateau, a large igneous province. Widespread fields of submarine volcanoes, some of which may be active, extend for distances of up to several hundred kilometers from the islands. The predominantly eastward-flowing Antarctic Circumpolar Current sweeps across the central Kerguelen Plateau, and extensive blooms of phytoplankton are observed on the Plateau down-current of HIMI. The goal of RV Investigator voyage IN2016_V01, conducted in January/February 2016, is to test the hypothesis that hydrothermal fluids, which cool active submarine volcanoes in the HIMI region, ascend from the seafloor and fertilise surface waters with iron, thereby enhancing biological productivity beginning with phytoplankton. Significant initial shipboard results include: Documentation, for the first time, of the role of active HIMI and nearby submarine volcanoes in supplying iron to the Southern Ocean. Nearshore waters had elevated dissolved iron levels. Although biomass was not correspondingly elevated, fluorescence induction data indicated highly productive resident phytoplankton. Discovery of >200 acoustic plumes emanating from the seafloor and ascending up to tens of meters into the water column near HIMI. Deep tow camera footage shows bubbles rising from the seafloor in an acoustic plume field north of Heard Island. Mapping 1,000 km2 of uncharted seafloor around HIMI. Submarine volcanic edifices punctuate the adjacent seafloor, and yielded iron-rich rocks similar to those found on HIMI, respectively. Acoustic plumes emanating from some of these features suggest active seafloor hydrothermal systems.

  17. CTD data from Rhode Island Sound collected from R/V Hope Hudner in 2009-2010 in support of Rhode Island Ocean Special Area Management Plan (NODC Accession 0109929)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset consists of 173 CTD casts in Rhode Island and Block Island Sounds obtained during 4 surveys. The surveys were performed during 22-24 September 2009, 7-8...

  18. Limited overwater dispersal and genetic differentiation of the snake-eyed skink (Cryptoblepharus nigropunctatus) in the Oceanic Ogasawara Islands, Japan.

    Science.gov (United States)

    Hayashi, Fumio; Shima, Akina; Horikoshi, Kazuo; Kawakami, Kazuto; Segawa, Ryoko D; Aotsuka, Tadashi; Suzuki, Tadashi

    2009-08-01

    The genetic differentiation and speciation of lizards on oceanic islands may be affected by their rate of overwater dispersal. Cryptoblepharus is one of the most geographically widespread scincid lizards throughout the Indo-Pacific and Australian regions. Cryptoblepharus nigropunctatus is the northernmost species of the genus, dwelling on several small Pacific islands. To examine the colonization history of this lizard, mitochondrial 16S rDNA and D-loop sequences were compared among populations of the Ogasawara Islands consisting of four island groups (the Muko-jima, Chichi-jima, Haha-jima, and Kazan groups), and an isolated island, Minamitori-shima (Marcus Island). These four groups and Minamitori-shima have not been connected to each other because each is surrounded by deep sea (>100 m). DNA analyses showed that the lizard populations on individual islands had each representative haplotypes. The ancestors of C. nigropunctatus probably arrived on the islands from the southern Pacific Ocean via wave dispersal and differentiated to produce the present state. They appear to have dispersed from their origin along two independent pathways: one between Kitaiwo-to (Kazan group) and the Muko-jima and Chichi-jima groups, and the other among the Minamitori-shima, Minamiiwo-to (Kazan group), and Haha-jima groups. Limited long-distance overwater dispersal may be responsible for the genetic structure of the C. nigropunctatus populations on these oceanic islands. However, among the small islands within the same island group, D-loop haplotypes were shared and the local genetic diversity was usually high, suggesting frequent gene flow across the same group of islands.

  19. High variability of dissolved iron concentrations in the vicinity of Kerguelen Island (Southern Ocean

    Directory of Open Access Journals (Sweden)

    F. Quéroué

    2015-01-01

    Full Text Available Dissolved Fe (dFe concentrations were measured in the upper 1300 m of the water column in the vicinity of Kerguelen Island as part of the second Kerguelen Ocean Plateau compared Study (KEOPS2. Concentrations ranged from 0.06 nmol L−1 in offshore, Southern Ocean waters, to 3.82 nmol L−1 within Hillsborough Bay, on the north-eastern coast of Kerguelen Island. Direct island runoff, glacial melting and resuspended sediments were identified as important inputs of dFe that could potentially fertilize the northern part of the plateau. A significant deep dFe enrichment was observed over the plateau with dFe concentrations increasing up to 1.30 nmol L−1 close to the seafloor, probably due to sediment resuspension and pore water release. Biological uptake was identified as a likely explanation for the decrease in dFe concentrations between two visits (28 days apart at a station above the plateau. Our results allowed studying other processes and sources, such as atmospheric inputs, lateral advection of enriched seawater, remineralization processes and the influence of the Polar Front (PF as a vector for Fe transport. Overall, heterogeneous sources of Fe over and off the Kerguelen Plateau, in addition to strong variability in Fe supply by vertical or horizontal transport, may explain the high variability in dFe concentrations observed during this study.

  20. Evidence for sex-segregated ocean distributions of first-winter wandering albatrosses at Crozet islands.

    Science.gov (United States)

    Åkesson, Susanne; Weimerskirch, Henri

    2014-01-01

    The highly mobile wandering albatrosses (Diomedea exulans) are adapted to navigate the extreme environment of the Southern Ocean and return to isolated islands to breed. Each year they cover several hundreds of thousands of kilometers during travels across the sea. Little is known about the dispersal flights and migration of young albatrosses. We tracked, by satellite telemetry, the departure dispersal of 13 juvenile wandering albatrosses from the Crozet Islands and compared them with tracks of 7 unrelated adults during the interbreeding season. We used the satellite tracks to identify different behavioural steps of the inherited migration program used by juvenile wandering albatrosses during their first solo-migration. Our results show that the juvenile wandering albatrosses from Crozet Islands moved to sex-specific foraging zones of the ocean using at departures selectively the wind. The results suggest that the inherited migration program used by the juvenile wandering albatrosses encode several distinct steps, based on inherited preferred departure routes, differences in migration distance between sexes, and selective use of winds. During long transportation flights the albatrosses were influenced by winds and both adult and juveniles followed approximate loxodrome (rhumbline) routes coinciding with the foraging zone and the specific latitudes of their destination areas. During the long segments of transportation flights across open seas the juveniles selected routes at more northerly latitudes than adults.

  1. Evidence for sex-segregated ocean distributions of first-winter wandering albatrosses at Crozet islands.

    Directory of Open Access Journals (Sweden)

    Susanne Åkesson

    Full Text Available The highly mobile wandering albatrosses (Diomedea exulans are adapted to navigate the extreme environment of the Southern Ocean and return to isolated islands to breed. Each year they cover several hundreds of thousands of kilometers during travels across the sea. Little is known about the dispersal flights and migration of young albatrosses. We tracked, by satellite telemetry, the departure dispersal of 13 juvenile wandering albatrosses from the Crozet Islands and compared them with tracks of 7 unrelated adults during the interbreeding season. We used the satellite tracks to identify different behavioural steps of the inherited migration program used by juvenile wandering albatrosses during their first solo-migration. Our results show that the juvenile wandering albatrosses from Crozet Islands moved to sex-specific foraging zones of the ocean using at departures selectively the wind. The results suggest that the inherited migration program used by the juvenile wandering albatrosses encode several distinct steps, based on inherited preferred departure routes, differences in migration distance between sexes, and selective use of winds. During long transportation flights the albatrosses were influenced by winds and both adult and juveniles followed approximate loxodrome (rhumbline routes coinciding with the foraging zone and the specific latitudes of their destination areas. During the long segments of transportation flights across open seas the juveniles selected routes at more northerly latitudes than adults.

  2. Orographic Gravity Waves above Small Islands in the Southern Ocean and Their Role in Climate

    Science.gov (United States)

    Alexander, M.; Grimsdell, A.

    2012-12-01

    Most of today's climate models struggle with systematic westerly biases in the stratospheric circulation that lead to a delayed breakdown of the stratospheric vortex in spring and associated effects on temperature and ozone loss. Ozone loss in recent decades and predicted ozone recovery in the 21st century has a first-order impact on surface winds and climate, highlighting the importance of these common model biases in stratospheric winds. The cause is long believed to be that the Southern Hemisphere lacks sources for orographic gravity waves and associated wave drag relative to the Northern Hemisphere. Some models include hemispherically asymmetric non-orographic gravity wave momentum fluxes in their parameterizations despite any clear observational or theoretical justification for such differences other than the need to obtain more realistic stratospheric simulations. Our work examines the role of orographic gravity waves above small islands in the Southern Ocean, which are too small to be resolved in most climate models. Orographic waves above these small islands have been observed as temperature anomalies in radiance observations of the Atmospheric Infrared Sounder (AIRS) instrument on the Aqua satellite. A previously analyzed case study with AIRS data concluded such waves above South Georgia Island in the South Atlantic can have a considerable impact on the stratospheric circulation, yet these effects are omitted in most climate models. In the present work, we use AIRS observations to examine occurrence frequencies and momentum fluxes above six island groups in the Southern Ocean. Further, detailed seasonal and interannual variations and areal maps of time-mean momentum fluxes are examined for two of these groups: South Georgia/Sandwich Islands and Heard/Kerguelen Islands. We examine the effects of winds at the surface and winds in the stratosphere to infer the relative roles of source intermittency, propagation effects, and observational filter effects on the

  3. Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragments

    Directory of Open Access Journals (Sweden)

    J. L. Tetreault

    2014-07-01

    Full Text Available Allochthonous accreted terranes are exotic geologic units that originated from anomalous crustal regions on a subducting oceanic plate and were transferred to the overriding plate during subduction by accretionary processes. The geographical regions that eventually become accreted allochthonous terranes include island arcs, oceanic plateaus, submarine ridges, seamounts, continental fragments, and microcontinents. These future allochthonous terranes (FATs contribute to continental crustal growth, subduction dynamics, and crustal recycling in the mantle. We present a review of modern FATs and their accreted counterparts based on available geological, seismic, and gravity studies and discuss their crustal structure, geological origin, and bulk crustal density. Island arcs have an average crustal thickness of 26 km, average bulk crustal density of 2.79 g cm−3, and have 3 distinct crustal units overlying a crust-mantle transition zone. Oceanic plateaus and submarine ridges have an average crustal thickness of 21 km and average bulk crustal density of 2.84 g cm−3. Continental fragments presently on the ocean floor have an average crustal thickness of 25 km and bulk crustal density of 2.81 g cm−3. Accreted allochthonous terranes can be compared to these crustal compilations to better understand which units of crust are accreted or subducted. In general, most accreted terranes are thin crustal units sheared off of FATs and added onto the accretionary prism, with thicknesses on the order of hundreds of meters to a few kilometers. In addition many island arcs, oceanic plateaus, and submarine ridges were sheared off in the subduction interface and underplated onto the overlying continent. And other times we find evidence of collision leaving behind accreted terranes 25 to 40 km thick. We posit that rheologically weak crustal layers or shear zones that were formed when the FATs were produced can be activated as detachments during subduction, allowing

  4. Petrology of the prehistoric lavas and dyke of the Barren Island, Andaman Sea, Indian Ocean

    Indian Academy of Sciences (India)

    M A Alam; D Chandrasekharam; O Vaselli; B Capaccioni; P Manetti; P B Santo

    2004-12-01

    Although Barren Island (Andaman Sea, Indian Ocean) witnessed several volcanic eruptions during historic times, the eruptions that led to the formation of this volcanic island occurred mainly during prehistoric times. It is still active and currently in the fumarolic stage. Its volcanic evolution appears to be characterized by a constructive phase with the piling up of lava flows and scoria deposits and Strombolian activities, followed by a sudden collapse of the main cone. Deposits of a possible caldera-forming eruption were not recognized earlier. After a period of peri-calderic hydromagmatic activity, whose deposits presently mantle inner and outer caldera walls, a new phase of intracalderic Vulcanian activities took place. A prominent dyke in the SE inner side of the caldera wall was recognized. Petrographically the lava flows and dyke are similar but they differ in their chemical composition (viz., SiO2, MgO, Ni, Cr) significantly. Similarity in major, minor and trace element composition (viz., K/La, K/Nb, K/Rb, K/Ti ratios) of these rocks together with Chondrite normalized trace element (Rb, Ba, Sr, P, Zr, Ti and Nb) and REE (La, Ce, Nd and Y) patterns of the Barren Island prehistoric lava flows and dyke and low-K lavas of Sunda Arc indicates that Barren Island must have evolved from a source similar to that of Sunda Arc lavas during the Quaternary Period.

  5. {sup 10}Be application to soil development on Marion Island, southern Indian Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Haussmann, N. [Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602 (South Africa); Aldahan, A., E-mail: ala.aldahan@geo.uu.s [Department of Earth Sciences, Uppsala University (Sweden); Department of Geology, United Arab Emirates University, Al-Ain (United Arab Emirates); Boelhouwers, J. [Department of Earth Sciences, Uppsala University (Sweden); Possnert, G. [Tandem Laboratory, Department of Engineering Science, Uppsala University (Sweden)

    2010-04-15

    Marion Island, located in the southern Indian Ocean, constitutes the summit of an active shield volcano. It is a small terrestrial environment where glacially abraded bedrock became exposed c x 10 kyr ago. These conditions provide an interesting possibility for the assessment of {sup 10}Be accumulation rates and their application to soil erosion studies on the island. {sup 10}Be concentrations were measured in precipitation, soil profiles and an Azorella selago cushion plant. The data reveal a {sup 10}Be precipitation flux several times higher than model prediction. Estimation of the {sup 10}Be accumulation based on the soil inventory suggests a span between 2000 and 7000 yr. This time span is not in accordance with the accepted notion that the island was covered with ice about 10,000 yr ago and suggests either removal of {sup 10}Be from the soil profile, an overestimated Holocene {sup 10}Be-flux or a delayed soil development history. Our results provide new data on {sup 10}Be concentrations from the sub-Antarctic islands and contribute towards enlarging the southern-hemisphere {sup 10}Be database.

  6. 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.

  7. Effects of disturbance on vegetation by sand accretion and erosion across coastal dune habitats on a barrier island.

    Science.gov (United States)

    Miller, Thomas E

    2015-01-12

    Coastal geomorphology and vegetation are expected to be particularly sensitive to climate change, because of disturbances caused by sea-level rise and increased storm frequency. Dunes have critical reciprocal interactions with vegetation; dunes create habitats for plants, while plants help to build dunes and promote geomorphological stability. These interactions are also greatly affected by disturbances associated with sand movement, either in accretion (dune building) or in erosion. The magnitude and intensity of disturbances are expected to vary with habitat, from the more exposed and less stable foredunes, to low-lying and flood-prone interdunes, to the protected and older backdunes. Permanent plots were established at three different spatial scales on St George Island, FL, USA, where the vegetation and dune elevation were quantified annually from 2011 to 2013. Change in elevation, either through accretion or erosion, was used as a measure of year-to-year disturbance over the 2 years of the study. At the scale of different dune habitats, foredunes were found to have the greatest disturbance, while interdunes had the least. Elevation and habitat (i.e. foredune, interdune, backdune) were significantly correlated with plant community composition. Generalized linear models conducted within each habitat show that the change in elevation (disturbance) is also significantly correlated with the plant community, but only within foredunes and interdunes. The importance of disturbance in exposed foredunes was expected and was found to be related to an increasing abundance of a dominant species (Uniola paniculata) in eroding areas. The significant effect of disturbance in the relatively stable interdunes was surprising, and may be due to the importance of flooding associated with small changes in elevation in these low-lying areas. Overall, this study documents changes in the plant community associated with elevation, and demonstrates that the foredune and interdune

  8. Machine Learning for benthic sand and maerl classification and coverage estimation in coastal areas around the Maltese Islands

    Directory of Open Access Journals (Sweden)

    Adam Gauci

    2016-10-01

    Full Text Available Analysis of the seabed composition over a large spatial scale is an interesting yet very challenging task. Apart from the field work involved, hours of video footage captured by cameras mounted on Remote Operated Vehicles (ROVs have to be reviewed by an expert in order to classify the seabed topology and to identify potential anthropogenic impacts on sensitive benthic assemblages. Apart from being time consuming, such work is highly subjective and through visual inspection alone, a quantitative analysis is highly unlikely to be made. This study investigates the applicability of various Machine Learning techniques for the automatic classification of the seabed into maerl and sand regions from recorded ROV footage. ROV data collected from depths ranging between 50 m and 140 m and at 9.5 km from the northeast coastline of the Maltese Islands, is processed. Through the application of the presented technique, 5.23 GB of data corresponding to 2 h and 24 min of footage which was collected during June 2013, was initially cleaned and classified. An estimate for the percentage cover of the two benthic habitats (sandy seabed and maerl was also computed by using artifacts encountered during the ROV survey and of known dimensions as a reference. Unlike other automatic seabed mapping techniques, the presented prototype processes video footage captured by a down-facing camera and not through acoustic backscatter. Image data is easier and much cheaper to capture. Promising results that indicate a very good degree of agreement between the true and predicted habitat type distribution values, were obtained.

  9. Non-Dive Activities for Islands in the Stream 2002 - Exploration of Outer Shelf and Slope Habitats off the Coast of North Carolina - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Expeditions Information System (EIS) contains information recorded by the NOAA Office of Ocean Exploration's data manager during the 2002 "Islands in the Stream...

  10. Temperature profiles from expendable bathythermograph (MBT) casts from the USCGC BURTON ISLAND in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) from 16 July 1973 to 26 September 1973 (NODC Accession 7301064)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the USCGC BURTON ISLAND in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the US Coast Guard...

  11. Temperature profiles from expendable bathythermograph (MBT) casts from the USCGC BURTON ISLAND in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 02 June 1974 to 08 September 1974 (NODC Accession 7400636)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the USCGC BURTON ISLAND in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Coast...

  12. Importance of dispersal routes that minimize open-ocean movement to the genetic structure of island populations.

    Science.gov (United States)

    Harradine, E L; Andrew, M E; Thomas, J W; How, R A; Schmitt, L H; Spencer, P B S

    2015-12-01

    Islands present a unique scenario in conservation biology, offering refuge yet imposing limitations on insular populations. The Kimberley region of northwestern Australia has more than 2500 islands that have recently come into focus as substantial conservation resources. It is therefore of great interest for managers to understand the driving forces of genetic structure of species within these island archipelagos. We used the ubiquitous bar-shouldered skink (Ctenotus inornatus) as a model species to represent the influence of landscape factors on genetic structure across the Kimberley islands. On 41 islands and 4 mainland locations in a remote area of Australia, we genotyped individuals across 18 nuclear (microsatellite) markers. Measures of genetic differentiation and diversity were used in two complementary analyses. We used circuit theory and Mantel tests to examine the influence of the landscape matrix on population connectivity and linear regression and model selection based on Akaike's information criterion to investigate landscape controls on genetic diversity. Genetic differentiation between islands was best predicted with circuit-theory models that accounted for the large difference in resistance to dispersal between land and ocean. In contrast, straight-line distances were unrelated to either resistance distances or genetic differentiation. Instead, connectivity was determined by island-hopping routes that allow organisms to minimize the distance of difficult ocean passages. Island populations of C. inornatus retained varying degrees of genetic diversity (NA = 1.83 - 7.39), but it was greatest on islands closer to the mainland, in terms of resistance-distance units. In contrast, genetic diversity was unrelated to island size. Our results highlight the potential for islands to contribute to both theoretical and applied conservation, provide strong evidence of the driving forces of population structure within undisturbed landscapes, and identify the islands

  13. Impact of 2004 Tsunami in the Islands of Indian Ocean: Lessons Learned

    Directory of Open Access Journals (Sweden)

    Georges Ramalanjaona

    2011-01-01

    Full Text Available Tsunami of 2004, caused by a 9.0 magnitude earthquake, is the most devastating tsunami in modern times, affecting 18 countries in Southeast Asia and Southern Africa, killing more than 250,000 people in a single day, and leaving more than 1.7 million homeless. However, less reported, albeit real, is its impact in the islands of the Indian Ocean more than 1,000 miles away from its epicenter. This is the first peer-reviewed paper on the 2004 tsunami events specifically in the eleven nations bordering the Indian Ocean, as they constitute a region at risk, due to the presence of tectonic interactive plate, absence of a tsunami warning system in the Indian Ocean, and lack established communication network providing timely information to that region. Our paper has a dual objective: the first objective is to report the 2004 tsunami event in relation to the 11 nations bordering the Indian Ocean. The second one is to elaborate on lessons learned from it from national, regional, and international disaster management programs to prevent such devastating consequences of tsunami from occurring again in the future.

  14. 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.

  15. Molecular and ultrastructural characterization of two ascomycetes found on sunken wood off Vanuatu islands in the deep Pacific ocean.

    Science.gov (United States)

    Dupont, Joëlle; Magnin, Sandrine; Rousseau, Florence; Zbinden, Magali; Frebourg, Ghislaine; Samadi, Sarah; de Forges, Bertrand Richer; Jones, E B Gareth

    2009-12-01

    A new genus of a deep-sea ascomycete with one new species, Alisea longicolla, is described based on analyses of 18S and 28S rDNA sequences and morphological characters. A. longicolla was found together with Oceanitis scuticella, on small twigs and sugar cane debris trawled from the bottom of the Pacific Ocean off Vanuatu Islands. Molecular and morphological characters indicate that both fungi are members of Halosphaeriaceae. Within this family, O. scuticella is phylogenetically related to Ascosalsum and shares similar ascospore morphology and appendage ontogeny. The genus Ascosalsum is considered congeneric with Oceanitis and Ascosalsum cincinnatulum, Ascosalsum unicaudatum and Ascosalsum viscidulum are transferred to Oceanitis, an earlier generic name.

  16. Changing depths of magma fractionation and stagnation during the evolution of an oceanic island volcano: La Palma (Canary Islands)

    Science.gov (United States)

    Galipp, Karsten; Klügel, Andreas; Hansteen, Thor H.

    2006-07-01

    La Palma (Canary Islands) represents an oceanic island volcano with an active rift zone, inferred to have formed during the last 800 ka following southward growth of the former radial-symmetrical stratovolcano Taburiente. We carried out clinopyroxene-melt thermobarometry and microthermometry of fluid inclusions to reconstruct the evolution of the magma plumbing systems over time and to understand the genetic relationship between Taburiente and the presently active Cumbre Vieja rift zone. Clinopyroxene-melt equilibria of phenocryst rims and glassy groundmass indicate pressures of 0.60-1.04 GPa (˜19-34 km depth) for Taburiente, 0.47-1.17 GPa (16-40 km) for the former Cumbre Nueva rift arm of Taburiente, and 0.50-0.78 GPa (16-26 km) for Bejenado volcano that formed after collapse of the Cumbre Nueva rift. These pressures are interpreted to reflect depths of magma storage and major crystal fractionation. CO 2-dominated fluid inclusions hosted by clinopyroxenes and olivines indicate pressures of formation or re-equilibration within an overall range of 0.25-0.61 GPa (˜8-19 km depth). Respective frequency maxima are at 0.41-0.50 GPa for Taburiente dunite xenoliths, 0.26-0.43 GPa for Cumbre Nueva ankaramites, and 0.26-0.32 GPa for Bejenado cumulate xenoliths. These pressures are interpreted to reflect levels of temporary magma stagnation during ascent. Our data show that the magma pathways during all volcanic phases including the presently active Cumbre Vieja rift [Klügel, A., Hansteen, T.H., Galipp, K., 2005. Magma storage and underplating beneath Cumbre Vieja volcano, La Palma (Canary Islands). Earth and Planetary Science Letters 236, 211-226] are characterized by two distinct storage levels: a system of prolonged storage within the upper mantle, and a system of short-term stagnation within the lower crust or near to the Moho. Both the mantle and crustal storage systems show a migration to shallower levels from 1.0 Ma to present, probably as a result of changing

  17. Satellite Tracking and Site Fidelity of Short Ocean Sunfish, Mola ramsayi, in the Galapagos Islands

    Directory of Open Access Journals (Sweden)

    Tierney M. Thys

    2017-01-01

    Full Text Available Ocean sunfishes, with their peculiar morphology, large size, and surface habits, are valuable assets in ecotourism destinations worldwide. This study investigates site fidelity and long-range movements of short ocean sunfish, Mola ramsayi (Giglioli 1883, at Punta Vicente Roca (PVR off Isabela Island in the Galapagos Islands. Five individuals were tracked between 32 and 733 days using ultrasonic receivers and transmitters. Two of the 5 were also tracked with towed pop-off satellite tags. One travelled to the equatorial front covering 2700 km in 53 days, with dive depths in the upper 360 m at temperatures between 9.2°C and 22°C. During its westward travel, dives extended to 1112 m (the deepest depth yet recorded for Molidae into temperatures ranging between 4.5°C and 23.2°C. The remaining four individuals demonstrated site fidelity to PVR and were detected at the site between 128–1361 times for a total of 3557 reports. Forty-eight percent of the reports occurred during daytime hours and 52% after dark. Presumed cleaning session durations had a median of 15 minutes and a maximum of nearly 100 minutes. No other ultrasonic arrays around Galapagos or in the Eastern Pacific regional network recorded the presence of tagged individuals. These data are combined with tourist vessel sightings and submersible observations to confirm Punta Vicente Roca as an important sunfish hotspot.

  18. Remnants of a Late Triassic ocean island in the Gufeng area, northern Tibet: Implications for the opening and early evolution of the Bangong-Nujiang Tethyan Ocean

    Science.gov (United States)

    Fan, Jian-Jun; Li, Cai; Wang, Ming; Liu, Yi-Ming; Xie, Chao-Ming

    2017-03-01

    In this paper we present new major and trace element compositions of basaltic rocks in the Gufeng ocean island (GFOI) area in the western segment of the Bangong-Nujiang Suture Zone, northern Tibet. Our aim was to assess the genesis of these rocks and discuss the implications of this new dataset for the evolution of the Bangong-Nujiang Tethyan Ocean. An ocean-island-type double-layer structure comprising a basaltic basement and an oceanic sedimentary cover sequence found within the GFOI provides direct evidence for the interpretation that the assemblage is a typical ocean island. The basalts in the GFOI can be divided into three types (named G1, G2 and G3 basalts), and these basalts range in composition from MORB to OIB types, which is typical of ocean islands. The G1 basalts have MORB-type affinities, possibly indicating the existence of MORB oceanic crust under the GFOI. The G2 basalts represent the early stage of formation of the GFOI, and are produced by the interaction of rising OIB-type basaltic magma and the existing MORB oceanic crust. The G3 basalts are typical OIB basalts and they are the products of the direct eruption of OIB-type basaltic magmas. The G3 basalts have high (La/Yb)N (12.3-14.4), (Ce/Yb)N (10.8-11.8), (La/Sm)N (2.39-2.76), and (Sm/Yb)N (4.89-5.23) ratios, indicating the presence of oceanic lithosphere below the GFOI with a thickness of 50-60 km. Geochemical analyses of the GFOI cherts show that they contain terrigenous material, indicating the GFOI formed close to a continental margin. Norian conodont fossils within the GFOI limestones indicate the GFOI formed during the Late Triassic. These data, combined with geological evidence and a half-space model of lithosphere cooling, where the thickness of the oceanic lithosphere is determined from the age of the lithosphere, indicate that the western segment of the Bangong-Nujiang Tethyan Ocean opened initially in the late Permian, expanded rapidly during the Early-Middle Triassic, and was a

  19. Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Jaffal, A. [Laboratoire d' Eco-Toxicologie, EA 2069 Vignes et Vins de Champagne, Universite de Reims Champagne-Ardenne, F51687 Reims Cedex 2 (France); Givaudan, N. [UMR8079, CNRS, Orsay F-91405 (France); Univ Paris-Sud, Ecologie Systematique et Evolution, Orsay F-91405 (France); Betoulle, S. [Laboratoire d' Eco-Toxicologie, EA 2069 Vignes et Vins de Champagne, Universite de Reims Champagne-Ardenne, F51687 Reims Cedex 2 (France); Terreau, A. [IPEV Institut Polaire Francais, F29280 Plouzane (France); Paris-Palacios, S.; Biagianti-Risbourg, S. [Laboratoire d' Eco-Toxicologie, EA 2069 Vignes et Vins de Champagne, Universite de Reims Champagne-Ardenne, F51687 Reims Cedex 2 (France); Beall, E. [ECOBIOP, UMR 1224 INRA-Universite de Pau-Pays de l' Adour F63310 St-Pee-sur-Nivelle (France); Roche, H., E-mail: helene.roche@u-psud.fr [UMR8079, CNRS, Orsay F-91405 (France); Univ Paris-Sud, Ecologie Systematique et Evolution, Orsay F-91405 (France)

    2011-05-15

    The Subantarctic Kerguelen Islands (49{sup o}S, 70{sup o}E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g{sup -1} lipid, and dioxin-like PCB was 19 and 69 ng g{sup -1} lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels. - Highlights: > First assessment of PCB contamination of biota in Kerguelen Islands, Sub-Antarctica. > PCB bioaccumulation level in trout varies from very high to undetectable. > Habitat and morphotype are the most influential factors on the variability. > Distribution pattern of PCBs in the muscle of fish is morphotype dependent. - Salmonids in hydrosystems of the Kerguelen Islands (Southern Ocean) show a high PCB bioaccumulation.

  20. A review of the conservation status of the threatened western Indian Ocean island tree Pisonia sechellarum (Nyctaginaceae

    Directory of Open Access Journals (Sweden)

    J. Gerlach

    2013-08-01

    Full Text Available The status of the tree Pisonia sechellarum F. Friedmann (Nyctaginaceae endemic to the western Indian Ocean is reviewed. Five populations have been located: four in the Seychelles Islands (three on Silhouette Island and one on Mahe and one on Mayotte. The species is associated with montane forest and ravine habitats and the genetic identity of different populations remains to be investigated. This species is considered to be endangered.

  1. Review on freshwater lens of lime-sand island in Nanhai Zhudao%南海诸岛灰沙岛淡水透镜体研究述评

    Institute of Scientific and Technical Information of China (English)

    赵焕庭; 王丽荣; 宋朝景

    2014-01-01

    Lime-sand islands develop in some coral reefs of South China Sea. Areas of these lime-sand islands are usually small. There are freshwater lens forming and developing under some lime-sand islands. In this paper, Yongxing Island is taken as an example to introduce the published studies on the freshwater lens in lime-sand islands. It includes the formation of the freshwater lens and its relationship with some factors, such as the geology, the climate, and the topography and vegetation of the island. Suggestions on the pumping, exploitation and management of the freshwater lens in Yongxing island are also introduced.%南海诸岛部分珊瑚礁上发育有灰沙岛,这些灰沙岛的面积多较小,其中一些灰沙岛地下形成淡水透镜体。以西沙群岛永兴岛为例,介绍了已有的永兴岛地下淡水透镜体的研究成果,包括灰沙岛淡水透镜体的形成和发育,其与地质、地形、气候和植被等因素的关系,以及淡水透镜体开发利用等问题,并提出进一步研究和管理的建议。

  2. Biogeography in Cellana (Patellogastropoda, Nacellidae) with Special Emphasis on the Relationships of Southern Hemisphere Oceanic Island Species

    Science.gov (United States)

    Nakano, Tomoyuki; Palma, Alvaro; Poulin, Elie

    2017-01-01

    Oceanic islands lacking connections to other land are extremely isolated from sources of potential colonists and have acquired their biota mainly through dispersal from geographically distant areas. Hence, isolated island biota constitutes interesting models to infer biogeographical mechanisms of dispersal, colonization, differentiation, and speciation. Limpets of the genus Cellana (Nacellidae: Patellogastropoda) show limited dispersal capacity but are broadly distributed across the Indo-Pacific including many endemic species in isolated oceanic islands. Here, we examined main distributional patterns and geographic boundaries among Cellana lineages with special emphasis in the relationships of Southern Hemisphere oceanic islands species. Phylogenetic reconstructions based on mtDNA (COI) recognized three main clades in Cellana including taxa from different provinces of the Indo-Pacific. Clear genetic discontinuities characterize the biogeography of Cellana and several lineages are associated to particular areas of the Indo-Pacific supporting the low dispersal capacity of the genus across recognized biogeographical barriers in the region. However, evolutionary relationships within Cellana suggest that long-distance dispersal processes have been common in the history of the genus and probably associated to the origin of the species in Hawaii and Juan Fernández Archipelago. Therefore, the presence of Cellana species in geographically distant Southern Hemisphere oceanic islands, such as the Juan Fernández Archipelago, suggests that long-distance dispersal mediated by rafting may have played an important role in the biogeography of the genus. PMID:28099466

  3. Mantle heterogeneities beneath the Northeast Indian Ocean as sampled by intra-plate volcanism at Christmas Island

    Science.gov (United States)

    Taneja, Rajat; Rushmer, Tracy; Blichert-Toft, Janne; Turner, Simon; O'Neill, Craig

    2016-10-01

    The intra-plate region of the Northeast Indian Ocean, located between the Ninetyeast Ridge and the North West Shelf of Australia, contains numerous submerged seamounts and two sub-aerially exposed volcanic island groups. While the Cocos (Keeling) Archipelago is a coral atoll, Christmas Island is the only sub-aerially exposed volcanic island and contains Late Cretaceous, Eocene and Pliocene lavas. The lavas are predominantly basaltic in composition, except for one sampled flow that is trachytic. Although the evolution of the western margin of Australia, and the seismicity in the intra-plate region, has received considerable attention, the origin of the seamount province in the Northeast Indian Ocean is still a matter of debate. In order to constrain the origin of volcanism on Christmas Island and the associated Seamount Province we analysed 14 Christmas Island samples for major and trace element abundances and 12 of these for Nd, Hf and Pb isotope compositions. The trace element patterns of the lavas are similar to many ocean island basalts, while high 208Pb/204Pb and 207Pb/204Pb at a given 206Pb/204Pb suggest affiliation with the DUPAL anomaly. The reconstructed position of Christmas Island during the Eocene (44-37 Ma) places the island in close proximity to the (present-day) upper mantle low-seismic velocity anomalies. Moreover, an enriched mantle (EM-2) type component in addition to the DUPAL anomaly is observed in the Eocene volcanic phase. The younger Pliocene (~ 4 Ma) sequences at Christmas Island are inferred to be the product of partial melting of existing material induced by lithospheric flexure.

  4. Autonomous ocean observations beneath Pine Island Glacier Ice Shelf, West Antarctica

    Science.gov (United States)

    Dutrieux, P.; Jenkins, A.; Jacobs, S.; Heywood, K. J.

    2015-12-01

    Warm circumpolar deep water reaching 3.5ºC above the in situ freezing point pervasively fills a network of glacially carved troughs in the Amundsen sea, West Antarctica, and melts and thins neighbouring ice shelves, including Pine Island glacier Ice Shelf (PIIS). Hydrographic, current, and microstructure observations obtained in austral summer 2009 and 2014 by an autonomous underwater vehicle beneath the PIIS are used here to detail the complex ice-ocean interaction and resulting ocean circulation. The theoretical schematic of deeply incoming warm and saline water melting the grounding line and generating a buoyant plume upwelling along the ice draft is generally consistent with observations. The cavity beneath PIIS is clearly divided in two by a seabed ridge, constraining the oceanic circulation and water masses distribution. On the seaward side of the ridge, a thick warm deep water layer circulates cyclonically and is overlaid by a thin meltwater layer. Only intermediate depth waters are allowed to overflow from the ridge top into the inner cavity, where a much thinner warm water layer is now overlaid by a thicker meltwater layer. At the ice/ocean interface, melt induced freshening is forcing an upwelling which in turn injects cyclonic vorticity and participates in creating a vigorous cyclonic recirculation in the inner cavity. The top of the ridge, where warm waters overflow in the inner cavity, is a dynamical boundary characterized by northward along-ridge currents up to 0.2 m/s and enhanced shear, thermal gradient, and mixing. Observations at two points at the ice interface indicate that the ocean remains stratified within 2 meters of the ice.

  5. Seismic anisotropy in the oceanic upper mantle: Evidence from the Bay of Islands Ophiolite Complex

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, N.I.; Salisbury, M.H.

    1979-08-10

    Olivine fabrics in 17 field-oriented ultramafics and mafics from three widely-spaced traverses in the Bay of Islands Ophiolite Complex, Newfoundland, display a remarkably uniform symmetry in which the olivine a crystallographic axes are aligned subprependicular to the sheeted dikes and the b and c axes lie within the plane of the sheeted dikes. The ultramafics studied consist entirely of tectonites; any olivine formed at the ridge crest by cumulus processes has since been re-oriented by translation gliding and/or syntectonic recrystallization. Deformation has extended from the ultramafics into the overlying gabbro, which suggests that in many oceanic regions the deepest levels of layer 3 consist of gabbroic tectonites. Compressional wave velocities computed from these petrofabrics display 5--6% anisotropy in the plane of the Mohorovicic discontinuity, with V/sub p/ fast parallel to the direction of spreading inferred from dike orientations. Since this pattern is identical to that observed for the oceanic upper mantle, it is concluded that the Bay of Islands Complex is a segment of oceanic crust and upper mantle. Shear wave velocity contours calculated from the same fabrics indicate that the upper mantle is nearly isotropic in terms of the maximum shear wave velocity, V/sub s//sub max/, but that the difference in velocity, ..delta..V/sub s/, between shear waves of orthogonal polarization traveling in the same direction may be sufficiently large parallel to the intersection of the Mohorovicic discontinuity and the sheeted dikes to allow detection of two distinct shear wave arrivals.

  6. Determination of the Ocean Tide Constituents Loading Based on GPS Measurements in the Chinese Offshore Islands

    Science.gov (United States)

    Liu, Y.; Wu, Z.; He, X.; Peng, L.

    2015-12-01

    Ocean tide loading largely affects the accuracy of GPS positioning. In turn, GPS measurements could be used to monitor the ocean tide loading effect. In this paper, 67-days GPS observations from two island GPS stations, respectively located in the East China Sea and the South China Sea, were collected and calculated in 30s sampling rate using the Precise Point Positioning (PPP) algorithm. The variation of GPS observed position time series are 2cm in the horizontal and 7cm in the vertical generated by the ocean tide loading effect and other error sources. With the power spectra analysis by the Fast Fourier Transform (FFT), the eigenvalues of the semidiurnal constituents and the diurnal constituents are obtained from the GPS estimates time series. The calculated frequencies are well agreements to the known within the error less than 1.5% for K1,Q1, O1, K2,S2, M2,N2, but P1 within 4.2%. The calculated amplitudes are also well consistent with the results from the global tide models FES2004,NAO.99 and GOT4.7. Their difference in the amplitude are mostly less than 5mm in the horizontal and the vertical direction, except K1 and M2. The maximum amplitude difference occurs in K1 and M2 up to 1.5cm in the vertical direction. In additional, two islands locate at the different transmission Channel, but they give the same calculated frequency in the horizontal and the vertical directional, respectively for 8 tidal constituents. This exhibits they belongs to the same tide wave system as in fact.

  7. Biodiversity and density of subtidal benthos of an oceanic tropical island (a comparison within the Pacific Ocean)

    Science.gov (United States)

    Sibaja-Cordero, Jeffrey A.; Troncoso, Jesús S.; Cortés, Jorge; Moreira, Juan; Vargas, José A.; Benavides-Varela, Catalina

    2016-09-01

    The marine macrofauna of the shallow sandy bottom of Isla del Coco, Costa Rica (5°32‧N-87°04‧W) was assessed in April 2010. Comparisons of richness, density and diversity between levels of exposure to ocean influence were carried out. During this study 15,407 specimens with a mean density of 1826 ind m- 2 were found between 3-75 m depth. The specimens were distributed in 267 taxa (29% new additions) with a mean of 55 ± 14 expected taxa m- 2. The values of density, richness and diversity were higher at the exposed coast, whereas they decreased at inner bays due to the influence of freshwater input. These estimates were compared with 40 studies in the Tropical Pacific Ocean (TPO). Taxa and density previously reported from the TPO were dependent on the area and depth range studied. Additionally, these parameters varied according to the sampling gear used. For example, higher densities were reported by using corers or boxcorers. The Shannon-Wiener index was most effective in identifying sediment and geographical patterns of variation along the TPO. Differences in these diversity parameters were also found between islands and mainland studies. Moreover, richness and density values from Isla del Coco were higher than the same parameters reported in studies using grabs in the TPO. At Isla del Coco annelids were dominant in terms of relative abundance (49.6%), followed by crustaceans (10.1%), mollusks (2.8%), and others faunal groups (37.5%). The faunistic composition at Isla del Coco differed when compared to the rest of localities of TPO due to the higher contribution of miscellaneous groups. In conclusion, the comparison with previous studies in the TPO indicate that islands like Isla del Coco have high numbers of taxa and diversity than those of the mainland, but lower density. However, this value is influenced by the sampling methodology. The taxa accumulation curve at Isla del Coco did not reach the asymptote, suggesting that an intensive sampling, especially

  8. Bioclimatic and vegetation mapping of a topographically complex oceanic island applying different interpolation techniques.

    Science.gov (United States)

    Garzón-Machado, Víctor; Otto, Rüdiger; del Arco Aguilar, Marcelino José

    2014-07-01

    Different spatial interpolation techniques have been applied to construct objective bioclimatic maps of La Palma, Canary Islands. Interpolation of climatic data on this topographically complex island with strong elevation and climatic gradients represents a challenge. Furthermore, meteorological stations are not evenly distributed over the island, with few stations at high elevations. We carried out spatial interpolations of the compensated thermicity index (Itc) and the annual ombrothermic Index (Io), in order to obtain appropriate bioclimatic maps by using automatic interpolation procedures, and to establish their relation to potential vegetation units for constructing a climatophilous potential natural vegetation map (CPNV). For this purpose, we used five interpolation techniques implemented in a GIS: inverse distance weighting (IDW), ordinary kriging (OK), ordinary cokriging (OCK), multiple linear regression (MLR) and MLR followed by ordinary kriging of the regression residuals. Two topographic variables (elevation and aspect), derived from a high-resolution digital elevation model (DEM), were included in OCK and MLR. The accuracy of the interpolation techniques was examined by the results of the error statistics of test data derived from comparison of the predicted and measured values. Best results for both bioclimatic indices were obtained with the MLR method with interpolation of the residuals showing the highest R2 of the regression between observed and predicted values and lowest values of root mean square errors. MLR with correction of interpolated residuals is an attractive interpolation method for bioclimatic mapping on this oceanic island since it permits one to fully account for easily available geographic information but also takes into account local variation of climatic data.

  9. Morphosedimentary evolution of carbonate sandy beaches at decadal scale : case study in Reunion Island , Indian Ocean

    Science.gov (United States)

    Mahabot, Marie-Myriam; Pennober, Gwenaelle; Suanez, Serge; Troadec, Roland; Delacourt, Christophe

    2017-04-01

    Global change introduce a lot of uncertainties concerning future trajectory of beaches by directly or indirectly modifying major driving factors. An improved understanding of the past shoreline evolution may help for anticipate future coastline response. However, in tropical environment, studies concerning carbonate beaches dynamics are scarce compared to open sandy beaches. Consequently, coral reef protected beaches morphological adjustment is still poorly understood and long-term evolution rate are poorly quantified in these specific environment. In this context, La Reunion Island, insular department of France located in Indian Ocean, constitute a favoured laboratory. This high volcanic island possesses 25 km of carbonate beaches which experience hydrodynamic forcing specific from tropical environment: cyclonic swell during summer and long period swell during winter. Because of degraded coral reef health and high anthropogenic pressure, 50% of the beaches are in erosion since 1970s. Beach survey has been conducted since 1990s by scientist and are now encompassed as pilot site within a French observatory network which guarantee long-term survey with high resolution observational techniques. Thus, La Reunion Island is one of the rare carbonate beach to be surveyed since 20 years. This study aims to examined and quantify beach response at decadal scale on carbonate sandy beaches of Reunion Island. The study focus on 12 km of beaches from Cap Champagne to the Passe de Trois-Bassins. The analyze of 15 beach profile data originated from historical and DGPS beach topographic data confirm long term trend to erosion. Sediment lost varies between 0.5 and 2 m3.yr-1 since 1998. However longshore current have led to accretion of some part of beach compartment with rate of 0.7 to 1.6 m3.yr-1. Wave climate was examined from in-situ measurement over 15 years and show that extreme waves associated with tropical cyclones and long period swell play a major role in beach dynamics

  10. 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.

  11. Impact of Intrathermocline eddies on seamount and oceanic island off Central Chile: Observation and modeling

    Science.gov (United States)

    Hormazabal, Samuel; Morales, Carmen; Cornejo, Marcela; Bento, Joaquim; Valencia, Luis; Auger, Pierre; Rodriguez, Angel; Correa, Marco; Anabalón, Valeria; Silva, Nelson

    2016-04-01

    In the Southeast Pacific, oceanographic processes that sustain the biological production necessary to maintain the ecosystems associated to seamounts and oceanic islands are still poorly understood. Recent studies suggest that the interaction of mesoscale and submesoescale eddies with oceanic islands and seamounts could be playing an important role in the time-space variability of primary production. In this work, research cruises, satellite data and Regional Ocean Modeling System (ROMS) results have been used to describe the main characteristics of intrathermocline eddies (ITE) and their impact on the Juan Fernández archipelago (JFA), off central Chile. 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). Between the RC and AS are located the westernmost seamounts (JF6 and JF5) of the Juan Fernández archipelago. Satellite altimetry data (sea surface height from AVISO) were used to detect and track mesoscale eddies through eddy-tracking algorithm. Physical, chemical and biological parameters as temperature, salinity, dissolved oxygen and fluorescence were measured in the water column at JF5 and JF6, and along the coast off central Chile (30-40°S). Results from the research cruise exhibit the interaction between an ITE and the seamount JF6. Eddy-tracking results showed that the ITE observed at the JF6 was formed at the coast off central-southern Chile, traveled ~900 km seaward and after ~9 months reached the JF5 and JF6 region. Observations along the Chilean coast confirmed that the coast corresponds to the formation area of the observed ITE. In this region, ITEs are represented by subsurface lenses (~100 km diameter; 400 m thickness) of homogeneous salinity, nutrient rich and oxygen-poor equatorial subsurface water mass (ESSW) which is transported poleward by the Peru-Chile undercurrent in the coastal band and seaward by ITEs. The effect of ITEs on the

  12. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... Shoals; naval aircraft bombing target area. (a) The danger zone. A circular area with a radius of 500...

  13. Key role of organic complexation of iron in sustaining phytoplankton blooms in the Pine Island and Amundsen Polynyas (Southern Ocean)

    NARCIS (Netherlands)

    Thuroczy, Charles-Edouard; Alderkamp, Anne-Carlijn; Laan, Patrick; Gerringa, Loes J. A.; Mills, Matthew M.; Van Dijken, Gert L.; De Baar, Hein J. W.; Arrigo, Kevin R.

    2012-01-01

    Primary productivity in the Amundsen Sea (Southern Ocean) is among the highest in Antarctica. The summer phytoplankton bloom in 2009 lasted for > 70 days in both the Pine Island and Amundsen Polynyas. Such productive blooms require a large supply of nutrients, including the trace metal iron (Fe).

  14. Assessment of relative Ti, Ta, and Nb (TITAN) enrichments in ocean island basalts

    Science.gov (United States)

    Peters, Bradley J.; Day, James M. D.

    2014-11-01

    sensitivity of trace element concentrations to processes governing solid-melt interactions has made them valuable tools for tracing the effects of partial melting, fractional crystallization, metasomatism, and similar processes on the composition of a parental melt. Recent studies of ocean island basalts (OIB) have sought to correlate Ti, Ta, and Nb (TITAN) anomalies to isotopic tracers, such as 3He/4He and 187Os/188Os ratios, which may trace primordial deep mantle sources. A new compilation of global OIB trace element abundance data indicates that positive TITAN anomalies, though statistically pervasive features of OIB, may not be compositional features of their mantle sources. OIB show a range of Ti (Ti/Ti* = 0.28-2.35), Ta (Ta/Ta* = 0.11-93.4), and Nb (Nb/Nb* = 0.13-17.8) anomalies that show negligible correlations with 3He/4He ratios, indicating that TITAN anomalies are not derived from the less-degassed mantle source traced by high-3He/4He. Positive TITAN anomalies can be modeled using variable degrees (0.1-10%) of nonmodal batch partial melting of garnet-spinel lherzolite at temperatures and pressures considered typical for OIB petrogenesis, and subjecting this partial melt to fractional crystallization and assimilation of mid-ocean ridge basalt-like crust (AFC). Correlations of TITAN anomalies with modal abundances of olivine and clinopyroxene in porphyritic Canary Islands lavas provide empirical support for this process and indicate that high abundances of these phases in OIB may create misleading trace element anomalies on primitive mantle-normalized spider diagrams. Because partial melting and AFC are common to all mantle-derived magmas, caution should be used when attributing TITAN anomalies to direct sampling of recycled or deep mantle sources by hotspots.

  15. Predicting Where a Radiation Will Occur: Acoustic and Molecular Surveys Reveal Overlooked Diversity in Indian Ocean Island Crickets (Mogoplistinae: Ornebius).

    Science.gov (United States)

    Warren, Ben H; Baudin, Rémy; Franck, Antoine; Hugel, Sylvain; Strasberg, Dominique

    2016-01-01

    Recent theory suggests that the geographic location of island radiations (local accumulation of species diversity due to cladogenesis) can be predicted based on island area and isolation. Crickets are a suitable group for testing these predictions, as they show both the ability to reach some of the most isolated islands in the world, and to speciate at small spatial scales. Despite substantial song variation between closely related species in many island cricket lineages worldwide, to date this characteristic has not received attention in the western Indian Ocean islands; existing species descriptions are based on morphology alone. Here we use a combination of acoustics and DNA sequencing to survey these islands for Ornebius crickets. We uncover a small but previously unknown radiation in the Mascarenes, constituting a three-fold increase in the Ornebius species diversity of this archipelago (from two to six species). A further new species is detected in the Comoros. Although double archipelago colonisation is the best explanation for species diversity in the Seychelles, in situ cladogenesis is the best explanation for the six species in the Mascarenes and two species of the Comoros. Whether the radiation of Mascarene Ornebius results from intra- or purely inter- island speciation cannot be determined on the basis of the phylogenetic data alone. However, the existence of genetic, song and ecological divergence at the intra-island scale is suggestive of an intra-island speciation scenario in which ecological and mating traits diverge hand-in-hand. Our results suggest that the geographic location of Ornebius radiations is partially but not fully explained by island area and isolation. A notable anomaly is Madagascar, where our surveys are consistent with existing accounts in finding no Ornebius species present. Possible explanations are discussed, invoking ecological differences between species and differences in environmental history between islands.

  16. Predicting Where a Radiation Will Occur: Acoustic and Molecular Surveys Reveal Overlooked Diversity in Indian Ocean Island Crickets (Mogoplistinae: Ornebius.

    Directory of Open Access Journals (Sweden)

    Ben H Warren

    Full Text Available Recent theory suggests that the geographic location of island radiations (local accumulation of species diversity due to cladogenesis can be predicted based on island area and isolation. Crickets are a suitable group for testing these predictions, as they show both the ability to reach some of the most isolated islands in the world, and to speciate at small spatial scales. Despite substantial song variation between closely related species in many island cricket lineages worldwide, to date this characteristic has not received attention in the western Indian Ocean islands; existing species descriptions are based on morphology alone. Here we use a combination of acoustics and DNA sequencing to survey these islands for Ornebius crickets. We uncover a small but previously unknown radiation in the Mascarenes, constituting a three-fold increase in the Ornebius species diversity of this archipelago (from two to six species. A further new species is detected in the Comoros. Although double archipelago colonisation is the best explanation for species diversity in the Seychelles, in situ cladogenesis is the best explanation for the six species in the Mascarenes and two species of the Comoros. Whether the radiation of Mascarene Ornebius results from intra- or purely inter- island speciation cannot be determined on the basis of the phylogenetic data alone. However, the existence of genetic, song and ecological divergence at the intra-island scale is suggestive of an intra-island speciation scenario in which ecological and mating traits diverge hand-in-hand. Our results suggest that the geographic location of Ornebius radiations is partially but not fully explained by island area and isolation. A notable anomaly is Madagascar, where our surveys are consistent with existing accounts in finding no Ornebius species present. Possible explanations are discussed, invoking ecological differences between species and differences in environmental history between

  17. Non-congruent colonizations and diversification in a coevolving pollination mutualism on oceanic islands.

    Science.gov (United States)

    Hembry, David H; Kawakita, Atsushi; Gurr, Neil E; Schmaedick, Mark A; Baldwin, Bruce G; Gillespie, Rosemary G

    2013-06-22

    A challenge for coevolutionary theory is how different types of interaction influence the diversification of coevolving clades. Reciprocal specialization is characteristic of certain coevolving, mutualistic interactions, but whether this specialization seen in ecological time constrains changes in patterns of interaction over evolutionary time remains unclear. Here, we examine the co-radiation of Glochidion trees (Phyllanthaceae: Phyllanthus s. l.) and pollinating, seed-predatory Epicephala moths (Lepidoptera: Gracillariidae) on young (mostly later than 5 Ma) oceanic islands in southeastern Polynesia. Epicephala are the sole known pollinators of Glochidion trees, and show extreme reciprocal specialization in continental Asia. We find that Glochidion and Epicephala diversified across these islands through repeated, non-congruent colonizations, and that one recently colonizing Epicephala lineage has spread across 12 host species in three archipelagos in less than 1 Myr. These results indicate that reciprocal specialization and coadaptation do not prevent dramatic changes in associations between intimately associated taxa over short evolutionary time scales. Not only are these host associations more dynamic than previously recognized, but these changes in patterns of interaction may play an important role in the diversification of coevolving taxa.

  18. Benthic macroinvertebrate based indices for assessing the ecological status of freshwaters on oceanic islands

    Directory of Open Access Journals (Sweden)

    PEDRO M. RAPOSEIRO

    2009-01-01

    Full Text Available Following the Water Framework Directive (2000/60/EC, macroinvertebrates are required biological elements for monitoring European aquatic ecosystems. Several efforts have been made towards establishing a biomonitoring programme for the Azores freshwater systems using benthic macroinvertebrates. However, little was previously known concerning Azorean freshwater macroinvertebrate fauna. Data from a major ongoing survey of macroinvertebrate freshwater fauna for two islands are presented and the use ofmacroinvertebrates as water quality indicators for the Azorean streams is evaluated. The upper, middle and lower reaches of streams longer than 10 km from São Miguel (10 and Santa Maria (1 were surveyed (a total of 33 samples. A total of 21 taxa were collected;Diptera, in particular chironomidae, were dominant; chironomids were collected from all sampling sites. The Azorean lotic fauna is characterized by low levels of abundance and the absence of macroinvertebrate groups commonly associated with continental systems.Traditional biotic indices, used to classify ecological quality, yielded poor to bad classifications despite little or no environmental impacts at the sampling sites. The paucityof macroinvertebrate fauna is probably due to the result of geological and physicochemical processes, the oceanic character of the islands, their volcanic origin, small size and geological youth and climate related factors such as seasonal peaks in rainfall. Considering these constraints, we demonstrate that watershed age plays a determinant role in shaping Azorean macroinvertebrate freshwater communities which can confound the water quality classification via the use of traditional biotic indices.

  19. Heavy Metal Content in Sewage Sludge: A Management Strategy for an Ocean Island

    Directory of Open Access Journals (Sweden)

    Cintia Hernández Sánchez

    2017-06-01

    Full Text Available In recent years, the generation of sewage sludge has increased worldwide. Correct processing and management of this waste concerns all countries. This work presents a study of metal contents, i.e. of Cd, Pb, Zn, Cr, Cu, and Ni, in sewage sludge from a wastewater treatment plant in the northeastern region of the island of Tenerife. The study aimed at examining the sludge for potential suitability as a farmland fertilizer. Detected metal levels for Pb, Zn, Cr, Cu, and Ni were extremely low (26.44, 544.01, 24.10, 37.05, and 8.04 mg/kg dw [dry weight], respectively. Cadmium levels were under quanti cation limit. Season-dependent, statistically significant differences (p < 0.05 in metal concentrations in sewage sludge were observed for Cu, Ni, Cr, and Pb. Consequently, the application of sewage sludge to fertilize nutrient-deficient agricultural soils and soils degraded by human activity represents a fast and straightforward solution to the lack of such resources, particularly in an oceanic island.

  20. [Updated inventory of mosquitoes (Diptera: Culicidae) of the island of La Réunion, Indian Ocean].

    Science.gov (United States)

    Boussès, P; Dehecq, J S; Brengues, C; Fontenille, D

    2013-05-01

    A literature analysis coupled with new entomological surveys conducted between 2009 and 2012 led to changes in the list of mosquito species present on the island of La Réunion. Using morphological criteria, Orthopodomyia arboricollis is replaced by Or. reunionensis. On the basis of morphometrical and genetic criteria, Culex univittatus is replaced by Cx. neavei. Cx. poicilipes, which was already reported missing 40 years ago, has not been found again. Anopheles arabiensis is confirmed as the only species of the Gambiae complex present on the island. Thus, twelve species are currently known. For each of them, elements of taxonomic, biological and medical interest are listed. An. arabiensis is a major vector of human Plasmodium (last case of indigenous malaria in 1967). In the Indian Ocean, Aedes albopictus and Ae. aegypti both are competent for transmitting dengue and chikungunya viruses. In Africa, Cx. quinquefasciatus transmits Wuchereria bancrofti and Cx. neavei transmits the Sindbis virus; both species also transmit the West Nile virus. Cx. tritaeniorhynchus is the major vector of Japanese Encephalitis virus in Asia. Two species are endemic (Ae. dufouri and Or. reunionensis), the ten other ones are also found in Madagascar and on the African continent (An. coustani, An. arabiensis, Ae. fowleri, Cx. tritaeniorhynchus, Cx. neavei, Cx. insignis, Lutzia tigripes), with three of them having also a cosmopolitan distribution (Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus). Among the twelve recorded taxa, eight species are anthropophilic, three are supposedly zoophilic and one is a predatory species. No new invasive anthropophilic species did settle on the island. Updated identification keys of larval and adult stages are proposed.

  1. The behavior and concentration of CO2 in the suboceanic mantle: Inferences from undegassed ocean ridge and ocean island basalts

    Science.gov (United States)

    Michael, Peter J.; Graham, David W.

    2015-11-01

    ppm, while primary NMORB magmas (> 500 km from ocean island hotspots) have 1840 ppm CO2. The annual flux of CO2 from mid-ocean ridges is 1.25 ± 0.16 × 1014 g/yr, with possible values as low as 0.93 and as high as 1.61 × 1014 g/yr. This amount is equivalent to approximately 0.3% of the anthropogenic addition of CO2 to Earth's atmosphere. NMORB mantle has 183 ppm CO2 (50 ppm C) based on simple melting models and 13% melting. More realistic estimates of incompatible element concentrations in the depleted mantle that are consistent with complex melting models yield much lower estimates for CO2 in the depleted mantle: around 60-130 ppm CO2, with large uncertainties that are more related to melting models than to CO2/Ba. CO2/Ba is not correlated with isotopic or trace element ratios, but there may be systematic regional mantle variations. Iceland melt inclusions and Gakkel Ridge MORBs have lower CO2/Ba ratios, showing that these regional high Ba anomalies are not accompanied by correspondingly high CO2 concentrations.

  2. In and out of Madagascar: dispersal to peripheral islands, insular speciation and diversification of Indian Ocean daisy trees (Psiadia, Asteraceae.

    Directory of Open Access Journals (Sweden)

    Joeri S Strijk

    Full Text Available Madagascar is surrounded by archipelagos varying widely in origin, age and structure. Although small and geologically young, these archipelagos have accumulated disproportionate numbers of unique lineages in comparison to Madagascar, highlighting the role of waif-dispersal and rapid in situ diversification processes in generating endemic biodiversity. We reconstruct the evolutionary and biogeographical history of the genus Psiadia (Asteraceae, a plant genus with near equal numbers of species in Madagascar and surrounding islands. Analyzing patterns and processes of diversification, we explain species accumulation on peripheral islands and aim to offer new insights on the origin and potential causes for diversification in the Madagascar and Indian Ocean Islands biodiversity hotspot. Our results provide support for an African origin of the group, with strong support for non-monophyly. Colonization of the Mascarenes took place by two evolutionary distinct lineages from Madagascar, via two independent dispersal events, each unique for their spatial and temporal properties. Significant shifts in diversification rate followed regional expansion, resulting in co-occurring and phenotypically convergent species on high-elevation volcanic slopes. Like other endemic island lineages, Psiadia have been highly successful in dispersing to and radiating on isolated oceanic islands, typified by high habitat diversity and dynamic ecosystems fuelled by continued geological activity. Results stress the important biogeographical role for Rodrigues in serving as an outlying stepping stone from which regional colonization took place. We discuss how isolated volcanic islands contribute to regional diversity by generating substantial numbers of endemic species on short temporal scales. Factors pertaining to the mode and tempo of archipelago formation and its geographical isolation strongly govern evolutionary pathways available for species diversification, and the

  3. Low-temperature alteration of oceanic island basalts and their contribution to transition metal circulation of the ocean

    Institute of Scientific and Technical Information of China (English)

    BU Wenrui; SHI Xuefa; PENG Jiantang; LIU Jihua; Zhang Mingjie; QI Liang

    2008-01-01

    The major elements,rare earth elements (REE) and trace elements of four basalt samples from central and western Pacific ferro-manganese crust provinces have been analyzed using chemical methods and ICP - MS,respectively.The results indicate that the samples have been extensively altered and that the contents of their major elements have changed significantly.However,the simi-larity of REE partition patterns and trace element contents of basalt samples to those of fresh oceanic island basalts (OIB) indicate that the basalt samples originated as OIB.Because of low-temperature alteration,the contents of Al2O3 ,Fe2O3 ,MnO,K2O and P2O5 increased,while MgO and FeO decreased.Active components,such as magnesium and iron,were leached from OIB resul-ting in the relative enrichment of SiO2.The leaching of active components can cause the relative enrichment of REE,while the precipitation of LREE-rich ferromanganese oxides in vesicles and fissures not only causes an increase of REE contents,but also induces "fractionation" of LREE and HREE.Based on the enrichment mechanism of REE contents,the theoretical quantities of precipitated ferromanganese oxides and the depleted quantities of active components are calculated :the depleted quantities of ac-tive components for the unit mass of fresh basalts vary in the range of 0.15~0.657,and the precipitated quantities of ferromanga-nese oxides for the unit mass of fresh basahs vary in the range of 0.006~0.042.Of the major elements,the two most depleted are iron,and magnesium,with 18.28%~70.95% of iron and 44.50%~93.94% of magnesium in the fresh basalts was leached out.Theoretical calculation and geochemistry results beth indicate that low-temperature alteration of basalts can supply abundant amount of metals to seawater,and may play an important role in ocean metal circulation.

  4. A Survey of ICESat Coastal Altimetry Applications: Continental Coast, Open Ocean Island, and Inland River

    Directory of Open Access Journals (Sweden)

    Timothy J. Urban

    2008-01-01

    Full Text Available ICESat satellite laser altimetry provides an unprecedented set of global elevation measurements of the Earth, yielding great detail over ice, land and ocean surfaces. Coastal regions in particular, including seamless land-water transitions, benefit from the small footprint (50 to 90 m, high resolution (40 Hz, ~170 m along-track, and high precision (2 to 3 cm of ICESat. We discuss the performance and character of ICESat data in three example coastal scenarios: continental coast (Louisiana-Mississippi Gulf Coast, USA, including Lake Pontchartrain, open ocean island (Funafuti, Tuvalu, and an inland river (confluence of Tapajos and Amazon rivers, Brazil. Water elevations are compared to tide gauge heights and to TOPEX and Jason-1 radar altimetry. In demonstrating the utilization of ICESat, we also present examples of: laser waveform shapes over a variety of surface types (water, land, and vegetation; vegetation canopy heights (detecting large-scale destruction from Hurricane Katrina comparing data before and after; sub-canopy surface water; measurements of waves; and examination of along-stream river slope and comparisons of river stage to hydrologically-driven GRACE geoid change.

  5. Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska final report

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Bruce Albert [Aleutian Pribilof Islands Association, Inc., Anchorage, AK (United States)

    2014-05-07

    The Aleutian Pribilof Islands Association was awarded a U.S. Department of Energy Tribal Energy Program grant (DE-EE0005624) for the Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska (Project). The goal of the Project was to perform a feasibility study to determine if a tidal energy project would be a viable means to generate electricity and heat to meet long-term fossil fuel use reduction goals, specifically to produce at least 30% of the electrical and heating needs of the tribally-owned buildings in False Pass. The Project Team included the Aleut Region organizations comprised of the Aleutian Pribilof Island Association (APIA), and Aleutian Pribilof Island Community Development Association (APICDA); the University of Alaska Anchorage, ORPC Alaska a wholly-owned subsidiary of Ocean Renewable Power Company (ORPC), City of False Pass, Benthic GeoScience, and the National Renewable Energy Laboratory (NREL). The following Project objectives were completed: collected existing bathymetric, tidal, and ocean current data to develop a basic model of current circulation at False Pass, measured current velocities at two sites for a full lunar cycle to establish the viability of the current resource, collected data on transmission infrastructure, electrical loads, and electrical generation at False Pass, performed economic analysis based on current costs of energy and amount of energy anticipated from and costs associated with the tidal energy project conceptual design and scoped environmental issues. Utilizing circulation modeling, the Project Team identified two target sites with strong potential for robust tidal energy resources in Isanotski Strait and another nearer the City of False Pass. In addition, the Project Team completed a survey of the electrical infrastructure, which identified likely sites of interconnection and clarified required transmission distances from the tidal energy resources. Based on resource and electrical data

  6. Mid- to late Holocene Indian Ocean Monsoon variability recorded in four speleothems from Socotra Island, Yemen

    Science.gov (United States)

    Van Rampelbergh, Maïté; Fleitmann, Dominik; Verheyden, Sophie; Cheng, Hai; Edwards, Lawrence; De Geest, Peter; De Vleeschouwer, David; Burns, Stephen J.; Matter, Albert; Claeys, Philippe; Keppens, Eddy

    2013-04-01

    Four stalagmites covering the last 7.0 ka were sampled on Socotra, an island in the northern Indian Ocean to investigate the evolution of the northeast Indian Ocean Monsoon (IOM) since the mid Holocene. On Socotra, rain is delivered at the start of the southwest IOM in May-June and at the start of the northeast IOM from September to December. The Haggeher Mountains act as a barrier forcing precipitation brought by the northeast winds to fall preferentially on the eastern side of the island, where the studied caves are located. δ18O and δ13C and Mg/Ca and Sr/Ca signals in the stalagmites reflect precipitation amounts brought by the northeast winds. For stalagmite STM6, this amount effect is amplified by kinetic effects during calcite deposition. Combined interpretation of the stalagmites' signals suggest a weakening of the northeast precipitation between 6.0 and 3.8 ka. After 3.8 ka precipitation intensities remain constant with two superimposed drier periods, between 0 and 0.6 ka and from 2.2 to 3.8 ka. No link can be established with Greenland ice cores and with the summer IOM variability. In contrast to the stable northeast rainy season suggested by the records in this study, speleothem records from western Socotra indicate a wettening of the southwest rainy season on Socotra after 4.4 ka. The local wettening of western Socotra could relate to a more southerly path (more over the Indian Ocean) taken by the southwest winds. Stalagmite STM5, sampled at the fringe between both rain areas displays intermediate δ18O values. After 6.2 ka, similar precipitation changes are seen between eastern Socotra and northern Oman indicating that both regions are affected similarly by the monsoon. Different palaeoclimatologic records from the Arabian Peninsula currently located outside the ITCZ migration pathway display an abrupt drying around 6 ka due to their disconnection from the southwest rain influence. Records that are nowadays still receiving rain by the southwest winds

  7. Geochemistry of oceanic igneous rocks - Ridges, islands, and arcs - With emphasis on manganese, scandium, and vanadium

    Science.gov (United States)

    Doe, B.R.

    1997-01-01

    increasing Mn is an indication of titanomagnetite removal. Dual compatible and incompatible trends with differentiation are found chiefly for Cu, Sc, and Sr. Distinguishing mid-ocean ridge basalts (MORB), oceanic-island volcanic rocks (OIV), and island-arc volcanic rocks (IAV) may be accomplished by plots of Ce/Yb versus Ba/Ce, where OIV plot to higher values of Ce/Yb than do MORB, and IAV data plot to higher values of Ba/Ce than do those of MORB. These ratios do not seem to be significantly affected by submarine weathering.

  8. Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

    Institute of Scientific and Technical Information of China (English)

    NIU Yaoling

    2009-01-01

    Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots"or "mantle plumes".While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis,our current understanding on the origin of OIB source material remains unsatisfactory,and some prevailing ideas need revision.One of the most popular views states that OIB source material is recycled oceanic crust (ROC).Among many problems with the ROC model,the ocean crust is simply too depleted (e.g.,[La/Sm]_(pM)>1) OIB.Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC,i.e.; terrigenous sediments).While both CC and OIB are enriched in many incompatible elements (e.g.,both have [La/Sm]PM>>1),the CC has characteristic enrichment in Pb and deletion in Nb,Ta,P and Ti.Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB.Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts,but they must be volumetrically insignificant in contributing to basalt magmatism.The observation that OIB are not only enriched in incompatible elements,but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism.H_2O and CO_2 rich incipient melt may form in the seismic low velocity zone (LVZ).This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere,forming the metasomatic vein lithologies.Erupted OIB melts may have three components:(1) fertile OIB source material from depth that is dominant,(2) the melt layer,and (3) assimilation of the metasomatic vein lithologies formed earlier in the growing/grown lithosphere.It is probable that

  9. Marine biodiversity of an Eastern Tropical Pacific oceanic island, Isla del Coco, Costa Rica

    Directory of Open Access Journals (Sweden)

    Jorge Cortés

    2012-11-01

    Full Text Available Isla del Coco (also known as Cocos Island is an oceanic island in the Eastern Tropical Pacific; it is part of the largest national park of Costa Rica and a UNESCO World Heritage Site. The island has been visited since the 16th Century due to its abundance of freshwater and wood. Marine biodiversity studies of the island started in the late 19th Century, with an intense period of research in the 1930’s, and again from the mid 1990’s to the present. The information is scattered and, in some cases, in old publications that are difficult to access. Here I have compiled published records of the marine organisms of the island. At least 1688 species are recorded, with the gastropods (383 species, bony fishes (354 spp. and crustaceans (at least 263 spp. being the most species-rich groups; 45 species are endemic to Isla del Coco National Park (2.7% of the total. The number of species per kilometer of coastline and by square kilometer of seabed shallower than 200m deep are the highest recorded in the Eastern Tropical Pacific. Although the marine biodiversity of Isla del Coco is relatively well known, there are regions that need more exploration, for example, the south side, the pelagic environments, and deeper waters. Also, several groups of organisms, such as the flatworms, nematodes, nemerteans, and gelatinous zooplankton, have been observed around the Island but have been poorly studied or not at all.La Isla del Coco es una isla oceánica en el Pacífico Tropical Oriental; es parte del Parque Nacional más grande de Costa Rica y es un sitio de Patrimonio Mundial. La isla ha sido visitada desde el Siglo XVI por su abundancia de agua dulce y árboles. Estudios de biodiversidad marina de la isla empezaron a finales del Siglo XIX, con un intenso período de investigación en la década de 1930, y de nuevo desde mediados de la década de 1990 al presente. La información sobre organismos marinos se encuentra dispersa y en algunos casos en publicaciones

  10. Coral calcification in a changing ocean

    Science.gov (United States)

    Kuffner, Ilsa B.

    2010-01-01

    Animals and plants that live in the ocean form skeletons and other hard parts by combining calcium ions and carbonate ions to create calcium carbonate. This process is called calcification. In tropical and subtropical oceans, the calcification of corals and other organisms creates reefs that protect islands, produce beautiful white-sand beaches, and create habitat for thousands of species that live on coral reefs.

  11. Mantle Plume Upwelling Rates: Evidence from U-Series in Young Ocean Island Basalts

    Science.gov (United States)

    Bourdon, B.; Turner, S. P.; Stracke, A.; Saal, A. E.

    2004-12-01

    U-series disequilibria measured in recent lavas at intraplate volcanoes provide a powerful probe to examine the validity of the plume model. U-Th and U-Pa fractionation produced during melting is a function of the melting rate. In turn, this parameter should scale with mantle upwelling velocities. Simply stated, a larger melting rate (larger mantle upwelling velocity) yields smaller Th and Pa excess relative to their parent nuclides. A number of observations supports this approach: (1) there is a negative correlation between 230Th excess and buoyancy fluxes (2) based on new measurements of 231Pa in the Azores, Iceland and the Galapagos and literature data, we show here that there is also a well defined correlation between 231Pa excess and buoyancy flux (3) For Hawaii, Iceland and the Azores, 230Th excess (or 231Pa excess) increases as a function of the distance from the centre of the `hotspot'. These observations suggests that `hotspot' buoyancy fluxes are associated with a greater melt production per unit of time and that the centre of `hotspot' corresponds to a faster mantle upwelling velocity than its periphery. This is therefore in strong support of a model where ocean islands are associated with faster upwelling at depth. However, there is in fact not a simple relationship between melt productivity and upwelling velocities. Notably, the presence of volatiles, of mafic lithologies or of variably enriched peridotitic source could all affect melting rate and hence U-Th-Pa fractionation. We have considered these issues in great detail using a large data base for the Azores islands. While there are clear variations in mantle source composition, they cannot explain the observations of increasing 231Pa/235U ratio with distance from the centre of the Azores hotspot . If we take into account the effect of water in the source of the Azores, it clearly affects the scaling between U-series fractionation and upwelling velocity but not the overall conclusions.

  12. An iron budget during the natural iron fertilisation experiment KEOPS (Kerguelen Islands, Southern Ocean

    Directory of Open Access Journals (Sweden)

    F. Chever

    2009-07-01

    Full Text Available Total dissolvable iron (TDFe was measured in the water column above and in the surrounding of the Kerguelen Plateau (Indian sector of the Southern Ocean during the KErguelen Ocean Plateau compared Study (KEOPS cruise. TDFe concentrations ranged from 0.90 to 65.6 nmol L−1 above the plateau and from 0.34 to 2.23 nmol L−1 offshore of the plateau. Station C1 located south of the plateau, near Heard Island, exhibited very high values (329–770 nmol L−1. Apparent particulate iron (Feapp, calculated as the difference between the TDFe and the dissolved iron measured on board (DFe represented 95±5% of the TDFe above the plateau, suggesting that particles and refractory colloids largely dominated the iron pool. This paper presents a budget of DFe and Feapp above the plateau. Lateral advection of water that had been in contact with the continental shelf of Heard Island seems to be the predominant source of Feapp and DFe above the plateau, with a supply of 9.7±2.3×106 and 8.3±6.7×103 mol d−1, respectively. The residence times of 1.7 and 48 days estimated for Feapp and DFe, respectively, indicate a rapid turnover in the surface water. A comparison between Feapp and total particulate iron (TPFe suggests that the total dissolved fraction is mainly constituted of small refractory colloids. This fraction does not seem to be a potential source of iron to the phytoplankton in our study. Finally, when taking into account the lateral supply of dissolved iron, the seasonal carbon sequestration efficiency was estimated at 154 000 mol C (mol Fe−1, which is 4-fold lower than the previously estimated value in this area but still 18-fold higher than the one estimated during the other study of a natural iron fertilisation experiment, CROZEX.

  13. An iron budget during the natural iron fertilisation experiment KEOPS (Kerguelen Islands, Southern Ocean

    Directory of Open Access Journals (Sweden)

    F. Chever

    2010-02-01

    Full Text Available Total dissolvable iron (TDFe was measured in the water column above and in the surrounding of the Kerguelen Plateau (Indian sector of the Southern Ocean during the KErguelen Ocean Plateau compared Study (KEOPS cruise. TDFe concentrations ranged from 0.90 to 65.6 nmol L−1 above the plateau and from 0.34 to 2.23 nmol L−1 offshore of the plateau. Station C1 located south of the plateau, near Heard Island, exhibited very high values (329–770 nmol L−1. Apparent particulate iron (Feapp, calculated as the difference between the TDFe and the dissolved iron measured on board (DFe represented 95±5% of the TDFe above the plateau, suggesting that particles and refractory colloids largely dominated the iron pool. This paper presents a budget of DFe and Feapp above the plateau. Lateral advection of water that had been in contact with the continental shelf of Heard Island seems to be the predominant source of Feapp and DFe above the plateau, with a supply of 9.7±3.6×106 and 8.3±11.6×103 mol d−1, respectively. The residence times of 1.7 and 48 days estimated for Feapp and DFe respectively, indicate a rapid turnover in the surface water. A comparison between Feapp and total particulate iron (TPFe suggests that the total dissolved fraction is mainly constituted of small refractory colloids. This fraction does not seem to be a potential source of iron to the phytoplankton in our study. Finally, when taking into account the lateral supply of dissolved iron, the seasonal carbon sequestration efficiency was estimated at 154 000 mol C (mol Fe−1, which is 4-fold lower than the previously estimated value in this area but still 18-fold higher than the one estimated during the other study of a natural iron fertilisation experiment, CROZEX.

  14. Solubility of iron and other trace elements in rainwater collected on the Kerguelen Islands (South Indian Ocean

    Directory of Open Access Journals (Sweden)

    A. Heimburger

    2013-10-01

    Full Text Available The soluble fraction of aerosols that is deposited on the open ocean is vital for phytoplankton growth. It is believed that a large proportion of this dissolved fraction is bioavailable for marine biota and thus plays an important role in primary production, especially in HNLC oceanic areas where this production is limited by micronutrient supply. There is still much uncertainty surrounding the solubility of atmospheric particles in global biogeochemical cycles and it is not well understood. In this study, we present the solubilities of seven elements (Al, Ce, Fe, La, Mn, Nd, Ti in rainwater on the Kerguelen Islands, in the middle of the Southern Indian Ocean. The solubilities of elements exhibit high values, generally greater than 70%, and Ti remains the least soluble element. Because the Southern Indian Ocean is remote from its dust sources, only a fraction of smaller aerosols reaches the Kerguelen Islands after undergoing several cloud and chemical processes during their transport, resulting in a drastic increase in solubility. Finally, we deduced an average soluble iron deposition flux of 27 ± 6 μg m−2 d−1 (~0.5 μmol m−2 d−1 for the studied oceanic area, taking into account a median iron solubility of 82% ± 18%.

  15. 厦门岛东南部海岸演变与泥沙输移%Coast evolution and sand transportation in east-southern Xiamen Island

    Institute of Scientific and Technical Information of China (English)

    陈坚; 蔡锋

    2001-01-01

    By means of coastal morphology and sediment investigation, shore change and littoral sand transportation rate calculation et al., characteristics of beach evolution in east-southern Xiamen Island were analyzed and studied. It is announced that the direction of net littoral sand transportation is from east-north to west-south and from east to west. Coast hereof is divided into 6 types, which are serious erosion type, mild-serious erosion type, mild erosion type, slight erosion type, slight deposit type and undefined type. Moreover, sand mining was defined as one of the most important factors for coast erosion.%通过海岸地貌调查、沉积物分布、岸线对比、沿岸输沙率计算等手段,分析研究了厦门岛东南部海岸海滩的演变特征.认为厦门岛东南部海岸的沿岸净输沙方向是由东北向西南,由东向西;黄厝湾中北部存在反向输沙.文中划分了中-强侵蚀海岸、中侵蚀海岸、中-弱侵蚀海岸、弱侵蚀海岸、弱淤积海岸和不确定海岸等6种类型.人工采沙是引起海岸侵蚀的最重要因素之一.

  16. Cyclic Explosivity in High Elevation Phreatomagmatic Eruptions at Ocean Island Volcanoes: Implications for Aquifer Pressurization and Volcano Flank Destabilization.

    Science.gov (United States)

    Tarff, R.; Day, S. J.; Downes, H.; Seghedi, I.

    2015-12-01

    Groundwater heating and pressurization of aquifers trapped between dikes in ocean island volcanoes has been proposed as a mechanism for destabilizing and triggering large-volume flank collapses. Previous modelling has indicated that heat transfer from sustained magma flow through dikes during eruption has the potential to produce destabilizing levels of pressure on time scales of 4 to 400 days, if the aquifers remain confined. Here we revisit this proposal from a different perspective. We examine evidence for pressure variations in dike-confined aquifers during eruptions at high elevation vents on ocean island volcanoes. Initially magmatic, these eruptions change to mostly small-volume explosive phreatomagmatic activity. A recent example is the 1949 eruption on La Palma, Canary Islands. Some such eruptions involve sequences of larger-volume explosive phases or cycles, including production of voluminous low-temperature, pyroclastic density currents (PDC). Here we present and interpret data from the Cova de Paul crater eruption (Santo Antao, Cape Verde Islands). The phreatomagmatic part of this eruption formed two cycles, each culminating with eruption of PDCs. Compositional and textural variations in the products of both cycles indicate that the diatreme fill began as coarse-grained and permeable which allowed gas to escape. During the eruption, the fill evolved to a finer grained, poorly sorted, less permeable material, in which pore fluid pressures built up to produce violent explosive phases. This implies that aquifers adjacent to the feeder intrusion were not simply depressurized at the onset of phreatomagmatic explosivity but experienced fluctuations in pressure throughout the eruption as the vent repeatedly choked and emptied. In combination with fluctuations in magma supply rate, driving of aquifer pressurization by cyclical vent choking will further complicate the prediction of flank destabilization during comparable eruptions on ocean island volcanoes.

  17. Ship Track for Islands in the Stream 2002 - Exploration of Outer Shelf and Slope Habitats off the Coast of North Carolina - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ship track of the R/V Seward Johnson during the 2002 "Islands in the Stream - Exploration of Outer Shelf and Slope Habitats off the Coast of North Carolina"...

  18. Islands in the Stream 2001 on NOAA Ship Gordon Gunter in the North Atlantic Ocean and the Gulf of Mexico between 20010510 and 20011004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Islands in the Stream expedition explored protected and unprotected deep water coral reefs and hard-bottom communities throughout the Gulf of Mexico and South...

  19. Submersible Data (Dive Waypoints) for Islands in the Stream 2002 - Exploration of Outer Shelf and Slope Habitats off the Coast of North Carolina - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data and information collected by the submersible Johnson Sea-Link II at waypoints along its track during one dive of the 2002 "Islands in the Stream - Outer Shelf...

  20. Ship Sensor Observations for Islands in the Stream 2002 - Exploration of Outer Shelf and Slope Habitats off the Coast of North Carolina - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly measurements made by selected ship sensors on the R/V Seward Johnson during the 2002 "Islands in the Stream - Exploration of Outer Shelf and Slope Habitats...

  1. Exploring the Tropical Land-Ocean Convective Intensity Difference through Surface Bowen Ratio and Island Size Variations

    Science.gov (United States)

    Hansen, Z.; Back, L. E.

    2014-12-01

    A better understanding of the mean distribution and variability in convective patterns is important for improving our understanding of the climate system. General circulation models (GCMs) still have trouble simulating climate variability in the tropics, where deep convection plays an important role in determining the mean climate and its variability. It has been observed that lightning flash rates over land in the tropics are orders of magnitude higher than those over the ocean. Because higher lightning flash rates tend to be associated with higher updraft velocities, deep convective updrafts over land are expected to be stronger than those over the tropical oceans. We hope to elucidate the physical mechanisms that influence updraft intensity using a cloud resolving model (CRM), which, unlike a GCM, is able to explicitly simulate individual convective updrafts. There are numerous hypotheses regarding what causes the discrepancy between land and ocean convection in the tropics. The hypotheses that we explore are variations in the Surface Bowen Ratio (SBR), as well as the existence of horizontal heterogeneities interacting with an ocean. We test these hypotheses in two different contexts: initial condition simulations, and radiative convective equilibrium (RCE) simulations. We modified the SBR of a region in RCE which by extension changes its boundary layer depth. The expectation in this case was that higher SBRs would lead to more enhanced convection. However, we find that higher SBRs have no effect or a slightly negative effect on updraft statistics in RCE simulations. We also looked at how the inclusion of differently sized islands affected convection in initial condition simulations. Previously, there had been discussion of a resonant island size that may produce more intense convection (Robinson, Sherwood, and Li 2008; Robinson et al. 2011,). We were able to reproduce predicted variations in convective intensity using differently sized islands. It remains to be

  2. Serological Evidence of Lyssaviruses among Bats on Southwestern Indian Ocean Islands

    Science.gov (United States)

    Mélade, Julien; McCulloch, Stewart; Ramasindrazana, Beza; Lagadec, Erwan; Turpin, Magali; Pascalis, Hervé; Goodman, Steven M.; Markotter, Wanda; Dellagi, Koussay

    2016-01-01

    We provide serological evidence of lyssavirus circulation among bats on southwestern Indian Ocean (SWIO) islands. A total of 572 bats belonging to 22 species were collected on Anjouan, Mayotte, La Réunion, Mauritius, Mahé and Madagascar and screened by the Rapid Fluorescent Focus Inhibition Test for the presence of neutralising antibodies against the two main rabies related lyssaviruses circulating on the African continent: Duvenhage lyssavirus (DUVV) and Lagos bat lyssavirus (LBV), representing phylogroups I and II, respectively. A total of 97 and 42 sera were able to neutralise DUVV and LBV, respectively. No serum neutralised both DUVV and LBV but most DUVV-seropositive bats (n = 32/220) also neutralised European bat lyssavirus 1 (EBLV-1) but not Rabies lyssavirus (RABV), the prototypic lyssavirus of phylogroup I. These results highlight that lyssaviruses belonging to phylogroups I and II circulate in regional bat populations and that the putative phylogroup I lyssavirus is antigenically closer to DUVV and EBLV-1 than to RABV. Variation between bat species, roost sites and bioclimatic regions were observed. All brain samples tested by RT-PCR specific for lyssavirus RNA were negative. PMID:27501458

  3. South West Indian Ocean islands tomato begomovirus populations represent a new major monopartite begomovirus group.

    Science.gov (United States)

    Delatte, Hélène; Martin, Darren P; Naze, Florence; Goldbach, Rob; Reynaud, Bernard; Peterschmitt, Michel; Lett, Jean-Michel

    2005-05-01

    Biological and molecular properties of Tomato leaf curl Madagascar virus isolates from Morondova and Toliary (ToLCMGV-[Tol], -[Mor]), Tomato leaf curl Mayotte virus isolates from Dembeni and Kahani (ToLCYTV-[Dem], -[Kah]) and a Tomato yellow leaf curl virus isolate from Reunion (TYLCV-Mld[RE]) were determined. Full-length DNA components of the five isolates from Madagascar, Mayotte and Reunion were cloned and sequenced and, with the exception of ToLCMGV-[Tol], were shown to be both infectious in tomato and transmissible by Bemisia tabaci. Sequence analysis revealed that these viruses had genome organizations of monopartite begomoviruses and that both ToLCMGV and ToLCYTV belong to the African begomoviruses but represent a distinct monophyletic group that we have tentatively named the South West islands of the Indian Ocean (SWIO). All of the SWIO isolates examined were apparently complex recombinants. None of the sequences within the recombinant regions closely resembled that of any known non-SWIO begomovirus, suggesting an isolation of these virus populations.

  4. AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab,...

  5. Circulation around La Réunion and Mauritius islands in the south-western Indian Ocean: A modeling perspective

    Science.gov (United States)

    Pous, Stéphane; Lazure, Pascal; André, Gaël.; Dumas, Franck; Halo, Issufo; Penven, Pierrick

    2014-03-01

    The objective of this study is to document the circulation in the vicinity of La Réunion and Mauritius islands, i.e., within 500 km offshore, on the intraseasonal time scale, using a high-resolution realistic modeling strategy. The simulated sea level anomalies, water mass properties, and large-scale circulation compare favorably with satellite and in situ observations. Our high-resolution simulation suggests that the currents around the islands are maximal locally, oriented southwestward, to the southeast of both islands which is not visible in low-resolution satellite observations. It also highlights the high degree of variability of the circulation, which is dominated by westward propagating features. The predominant time scale of variability is 60 days. This coincides with the period of a barotropic mode of variability confined to the Mascarene Basin. The characteristics of the westward propagating anomalies are related to baroclinic Rossby waves crossing the Indian Ocean but only in the long-wave resting ocean limit. Tracking those anomalies as eddies shows that they also have a meridional tendency in their trajectory, northward for cyclones and southward for anticyclones, which is consistent with previous studies. Sensitivity experiments suggest that they are predominantly advected from the east, but there is also local generation in the lee of the islands, due to interaction between the circulation and topography.

  6. Sex, Status, and Sand: California Academy of Sciences' Teen Interns Examine Trends of the Pacific Mole Crab (Emerita analoga) at Ocean Beach, San Francisco

    Science.gov (United States)

    Chu, J. B.; Conrad-Saydah, A.; Cohen, S.; Tom, R.; Robins-Moloney, M.; Masters, D.; Mason, K.; Alfaro, F.

    2003-12-01

    Student interns from the California Academy of Sciences' Careers in Sciences program monitored the Pacific mole crab (Emerita analoga), or sand crabs, in collaboration with the Farallones Marine Sanctuary Association. These small crustaceans live in the swash zone of the sandy beach habitat. Sand crabs are important in the food web, and therefore their status can help indicate the health of the larger environment. The interns helped the Gulf of the Farallones National Marine Sanctuary by monitoring the abundance and distribution of sand crabs at Ocean Beach in San Francisco, California. Students set up transects perpendicular to the shoreline, collected 10 samples along the transect, measured the carapace length, determined the sex of each crab, and checked for the presence of eggs. Students monitored June through September, 2003. Trends examined included differences in the gender ratio, size frequency, and distribution along the beach. Students also compared their data to other student data taken from other sites in San Francisco and Marin counties during 2001-2003 from the online database at http://www.sandcrabs.org. Using comparisons, interns were able to better understand the processes and significance of studying marine species. Implementation of the project was invaluable in aiding the interns in their understanding of the natural sciences and the role of monitoring habitats in environmental health.

  7. The Cotoncello Shear Zone (Elba Island, Italy): The deep root of a fossil oceanic detachment fault in the Ligurian ophiolites

    Science.gov (United States)

    Frassi, Chiara; Musumeci, Giovanni; Zucali, Michele; Mazzarini, Francesco; Rebay, Gisella; Langone, Antonio

    2017-05-01

    The ophiolite sequences in the western Elba Island are classically interpreted as a well-exposed ocean-floor section emplaced during the Apennines orogeny at the top of the tectonic nappe-stack. Stratigraphic, petrological and geochemical features indicate that these ophiolite sequences are remnants of slow-ultraslow spreading oceanic lithosphere analogous to the present-day Mid-Atlantic Ridge and Southwest Indian Ridge. Within the oceanward section of Tethyan lithosphere exposed in the Elba Island, we investigated for the first time a ​10s of meters-thick structure, the Cotoncello Shear Zone (CSZ), that records high-temperature ductile deformation. We used a multidisciplinary approach to document the tectono-metamorphic evolution of the shear zone and its role during spreading of the western Tethys. In addition, we used zircon U-Pb ages to date formation of the gabbroic lower crust in this sector of the Apennines. Our results indicate that the CSZ rooted below the brittle-ductile transition at temperature above 800 °C. A high-temperature ductile fabric was overprinted by fabrics recorded during progressive exhumation up to shallower levers under temperature < 500 °C. We suggest that the CSZ may represent the deep root of a detachment fault that accomplished exhumation of an ancient oceanic core complex (OCC) in between two stages of magmatic accretion. We suggest that the CSZ represents an excellent on-land example enabling to assess relationships between magmatism and deformation when extensional oceanic detachments are at work.

  8. The monitoring of atmospheric mercury species in the Southern Indian Ocean at Amsterdam Island (38°S

    Directory of Open Access Journals (Sweden)

    Barret M.

    2013-04-01

    Full Text Available The role of oceans in the global cycle of mercury is still poorly characterized, mainly because of a lack a long-term data on atmospheric mercury concentrations in the remote Southern Ocean. In the frame of GMOS (Global Mercury Observation System, we present here the first results from a new monitoring station at Amsterdam Island in the Southern Indian Ocean. For the period January to April 2012, we recorded mean concentration of gaseous elemental mercury (GEM, reactive gaseous mercury (RGM and particulate-bounded mercury (PHg of 1.03 ng m−3, 0.37 and 0.34 pg m−3 respectively. While GEM concentrations showed little variations, RGM and PHg exhibited fast variations with alternation of value below the instrumental detection limit and maximum values up to 4 pg m−3.

  9. Predecessors of the 2004 Indian Ocean Tsunami: Inferences Based on Historical, Archeological and Geological Evidence From the Indian Coast and the Andaman-Nicobar Islands

    Science.gov (United States)

    Rajendran, C.; Rajendran, K.; Machado, T.

    2007-12-01

    The 2004 tsunami is an unprecedented event in the Indian Ocean. Never in the recent or distant history of the region has such a transoceanic event of devastating proportion is known to have been reported. Obviously, apparent lack of historical references in the culturally ancient Southeast Asian region suggests rarity of such events. Therefore, a major question that has been posed since the 2004 tsunami is whether similar events have occurred in the region in the past. If there are predecessors, what is the frequency of such events? Resolving this question is of crucial importance in developing the recurrence history of megathrust earthquakes and assessing the tsunami hazard of the region. Our strategy has been to tackle this problem using historical and archeological data, combined with geological investigations in the affected regions of the Indian coast, including the Andaman- Nicobar Islands. Citations from south India on ancient tsunami include classic Tamil texts, which mention about a devastating sea surge around A.D. 950 in the southeastern coast of India. Our studies were focused on two ancient port cities on the east coast of India: Mammallapuram and Kaveripattinam, the latter being a major township during the first millennium. The 2004 tsunami had scoured Mammallapuram beach exposing the basements of older temples. We have identified a discordant sand deposit sandwiched between two bricklayers at a site where the ruins of different generations of temples have been excavated. The radiocarbon dates suggest that this was deposited during 955+/-30 yr B.P., close to the historically documented period of devastation of this site by a sea surge. Excavations at Kaveripattinam, located 200 km to the south, revealed a widely distributed occupation horizon of A.D. 8-10 century, marked by a superjacent sand layer. We suspect that this layer represents the A.D. 950- sea incursion mentioned in the in the classic Tamil texts, also in line with the archeological

  10. Phlebotomine sand flies of edible-nest swiftlet cave of Lang Ga Jiew Island, Chumphon province, Thailand.

    Science.gov (United States)

    Chittsamart, B; Samruayphol, Suchada; Sungvorayothin, Sangsit; Pothiwat, Ratcharin; Samung, Yudthana; Apiwathnasorn, Chamnarn

    2015-09-01

    The present study reported for the first time phlebotomine sandfly species inhabiting edible-nest swiftlet cave of the isolated island, based on field collections made during June 2010-May 2011. The insect diversity was relatively lower to that of mainland caves. All species, Phlebotomus stantoni, Sergentomyia anodontis, Sergentomyia bailyi, Sergentomyia gemmea, Sergentomyia hodgsoni and Sergentomyia punjabensis were either endemic island species or native elsewhere in Thailand. Sergentomyia hodgsoni was the most prevalent species accounted for 94.7% and classified as a troglophile species. Seasonal pattern of the phlebotomine abundance and some aspects of their population characteristics were described and discussed. Two ectoparasites, Ornithodorus and Paracimex sp. were also incidentally collected from the swiftlet cave.

  11. Seasonal evolution of the upper-ocean adjacent to the South Orkney Islands, Southern Ocean: Results from a “lazy biological mooring”

    Science.gov (United States)

    Meredith, Michael P.; Nicholls, Keith W.; Renfrew, Ian A.; Boehme, Lars; Biuw, Martin; Fedak, Mike

    2011-07-01

    A serendipitous >8-month time series of hydrographic properties was obtained from the vicinity of the South Orkney Islands, Southern Ocean, by tagging a southern elephant seal ( Mirounga leonina) on Signy Island with a Conductivity-Temperature-Depth/Satellite-Relay Data Logger (CTD-SRDL) in March 2007. Such a time series (including data from the austral autumn and winter) would have been extremely difficult to obtain via other means, and it illustrates with unprecedented temporal resolution the seasonal progression of upper-ocean water mass properties and stratification at this location. Sea ice production values of around 0.15-0.4 m month -1 for April to July were inferred from the progression of salinity, with significant levels still in September (around 0.2 m month -1). However, these values presume that advective processes have negligible effect on the salinity changes observed locally; this presumption is seen to be inappropriate in this case, and it is argued that the ice production rates inferred are better considered as "smeared averages" for the region of the northwestern Weddell Sea upstream from the South Orkneys. The impact of such advective effects is illustrated by contrasting the observed hydrographic series with the output of a one-dimensional model of the upper-ocean forced with local fluxes. It is found that the difference in magnitude between local (modelled) and regional (inferred) ice production is significant, with estimates differing by around a factor of two. A halo of markedly low sea ice concentration around the South Orkneys during the austral winter offers at least a partial explanation for this, since it enabled stronger atmosphere/ocean fluxes to persist and hence stronger ice production to prevail locally compared with the upstream region. The year of data collection was an El Niño year, and it is well-established that this phenomenon can impact strongly on the surface ocean and ice field in this sector of the Southern Ocean, thus

  12. The Influence of Baker Bay and Sand Island on Circulations in the Mouth of the Columbia River

    Science.gov (United States)

    2014-06-01

    form (y = mx + b) to become  * 0(z) ln( ) ln( ) c c u u z z    (3) where y is , m is *c u  and x is  0ln( ) ln( )z z . Linear regression...cycle, the neap-spring cycle, the river discharge cycle, the seasonal temperature and precipitation cycle and ocean upwelling and downwelling

  13. Eighteen years of geochemical monitoring at the oceanic active volcanic island of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Asensio-Ramos, María; Alonso, Mar; Sharp, Emerson; Woods, Hannah; Barrancos, José; Pérez, Nemesio M.

    2016-04-01

    We report herein the latest results of a diffuse CO2 efflux survey at El Hierro volcanic system carried out during the summer period of 2015 to constrain the total CO2 output from the studied area a during post-eruptive period. El Hierro Island (278 km2) is the youngest and the SW-most of the Canary Islands. On July 16, 2011, a seismic-volcanic crisis started with the occurrence of more than 11,900 seismic events and significant deformation along the island. On October 10, 2011, the dominant character of seismicity changed dramatically from discrete earthquakes to continuous tremor, a clear indication that magma was rapidly approaching the surface immediately before the onset of the eruption, October 12. Eruption was declared over on 5 March, 2012. In order to monitor the volcanic activity of El Hierro Island, from 1998 to 2015 diffuse CO2 emission studies have been performed at El Hierro volcanic system in a yearly basis (˜600 observation sites) according to the accumulation chamber method. Spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. To quantify the total CO2 emission from the studied area, 100 simulations for each survey have been performed. During the eruption period, soil CO2 efflux values range from non-detectable (˜0.5 g m-2 d-1) up to 457 g m-2 d-1, reaching in November 27, 2011, the maximum CO2 output estimated value of all time series, 2,398 t d-1, just before the episodes of maximum degassing observed as vigorous bubbling at the sea surface and an increment in the amplitude of the tremor signal. During the 2015 survey, soil CO2 efflux values ranged from non-detectable up to 41 g m-2 d-1. The spatial distribution of diffuse CO2 emission values seemed to be controlled by the main volcano structural features of the island. The total diffuse CO2 output released to atmosphere was estimated at 575 ± 24 t d-1, value slightly higher that the background CO2 emission estimated at 422 t d-1 (Melián et

  14. Digital Video taken during the 3-person submersible Clelia dive 609 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, August 30, 2001 (NCEI Accession 0037122)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The video data in this accession was captured during the Islands in the Stream mission of 2001. Islands in the Stream was a three-month scientific expedition to...

  15. Digital video taken during the 3-person submersible Clelia dive 606 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, August 29, 2001 (NCEI Accession 0039739)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The video data in this accession was captured during the Islands in the Stream mission of 2001. Islands in the Stream was a three-month scientific expedition to...

  16. Integrated Ocean and Coastal Mapping (IOCM) Project WA1002: PUDGET SOUND - WHIDBEY ISLAND, WA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objective of Integrated Ocean and Coastal Mapping (IOCM) is to improve the coordination among federal, state and local government, non-governmental and private...

  17. Laboratory Seismic Monitoring and X-ray CT imaging of Supercritical CO2 Injection in Reservoir Sand: WESTCAB King Island Project

    Science.gov (United States)

    Nakashima, S.; Kneafsey, T. J.; Nakagawa, S.; Harper, E. J.

    2013-12-01

    The Central Valley of California contains promising locations for on-shore geologic CO2 storage. DOE's WESTCARB (West Coast Regional Carbon Sequestration Partnership) project drilled and cored a borehole (Citizen Green Well) at King Island (near Stockton, CA) to study the CO2 storage capability of saline and gas-bearing formations in the southwestern Sacramento Basin. Potential reservoirs encountered in the borehole include Domengine, Mokelumne River (primary target), and Top Starkey formations. In anticipation of geophysical monitoring of possible CO2 injection into this particular borehole and of the long-term migration of the CO2, we conducted small-scale CO2 injection experiments on three core samples retrieved from the well (Mokelumne River sand A and B) and from a mine outcrop (Domengine sandstone). During the experiment, a jacketed core sample (diameter 1.5 inches, length 4.0-6.0 inches) saturated with brine- (1% NaCl aq.) was confined within a pressure vessel via compressed nitrogen to 3,500-4,000psi, and supercritical CO2 was injected into the core at 2,000-2,500psi and 45-60 degrees C. The CO2 pressure and temperature were adjusted so that the bulk elastic modulus of the CO2 was close to the expected in-situ modulus--which affects the seismic properties most--while keeping the confining stress within our experimental capabilities. After the CO2 broke through the core, fresh brine was re-injected to remove the CO2 by both displacement and dissolution. Throughout the experiment, seismic velocity and attenuation of the core sample were measured using the Split Hopkinson Resonant Bar method (Nakagawa, 2012, Rev. Sci. Instr.) at near 1 kHz (500Hz--1.5 kHz), and the CO2 distribution determined via x-ray CT imaging. In contrast to relatively isotropic Mokelumne sand A, Domengine sandstone and Mokelumne sand B cores exhibited CO2 distributions strongly controlled by the bedding planes. During the CO2 injection, P-wave velocity and attenuation of the layered

  18. Biostratigraphic evidence of dramatic Holocene uplift of Robinson Crusoe Island, Juan Fernández Ridge, SE Pacific Ocean

    Directory of Open Access Journals (Sweden)

    P. Sepúlveda

    2014-09-01

    Full Text Available A study of the biostratigraphy and sedimentology of Holocene deposits on Robinson Crusoe Island (RCI on the Juan Fernández Ridge (JFR indicates that a~dramatic but localized uplift occurred since 8000 BP, at a rate of about 8.5 mm yr−1. In fact, supratidal flats and sand layers with marine gastropods (mostly Nerita sp. are now exposed ca. 70 m a.s.l., and covered by transitional dunes. The last volcanic activity on RCI occurred at ca. 0.8 Ma (active hotspot located 280 km further west and there is no sign of a compensating bulge that explains this uplift, isobaths of the sea floor instead suggesting general subsidence. However, modeling indicates that large-scale landslides followed by isostatic rebound are a viable explanation, partially reflected in the low-resolution bathymetry of the area.

  19. Biostratigraphic evidence of dramatic Holocene uplift of Robinson Crusoe Island, Juan Fernández Ridge, SE Pacific Ocean

    Science.gov (United States)

    Sepúlveda, P.; Le Roux, J. P.; Lara, L. E.; Orozco, G.; Astudillo, V.

    2014-09-01

    A study of the biostratigraphy and sedimentology of Holocene deposits on Robinson Crusoe Island (RCI) on the Juan Fernández Ridge (JFR) indicates that a~dramatic but localized uplift occurred since 8000 BP, at a rate of about 8.5 mm yr-1. In fact, supratidal flats and sand layers with marine gastropods (mostly Nerita sp.) are now exposed ca. 70 m a.s.l., and covered by transitional dunes. The last volcanic activity on RCI occurred at ca. 0.8 Ma (active hotspot located 280 km further west) and there is no sign of a compensating bulge that explains this uplift, isobaths of the sea floor instead suggesting general subsidence. However, modeling indicates that large-scale landslides followed by isostatic rebound are a viable explanation, partially reflected in the low-resolution bathymetry of the area.

  20. Rapid succession of plant associations on the small ocean island of Mauritius at the onset of the Holocene

    Science.gov (United States)

    de Boer, Erik J.; Hooghiemstra, Henry; Vincent Florens, F. B.; Baider, Cláudia; Engels, Stefan; Dakos, Vasilis; Blaauw, Maarten; Bennett, K. D.

    2013-05-01

    The island of Mauritius offers the opportunity to study the poorly understood vegetation response to climate change on a small tropical oceanic island. A high-resolution pollen record from a 10 m long peat core from Kanaka Crater (560 m elevation, Mauritius, Indian Ocean) shows that vegetation shifted from a stable open wet forest Last Glacial state to a stable closed-stratified-tall-forest Holocene state. An ecological threshold was crossed at ˜11.5 cal ka BP, propelling the forest ecosystem into an unstable period lasting ˜4000 years. The shift between the two steady states involves a cascade of four abrupt (<150 years) forest transitions in which different tree species dominated the vegetation for a quasi-stable period of respectively ˜1900, ˜1100 and ˜900 years. We interpret the first forest transition as climate-driven, reflecting the response of a small low topography oceanic island where significant spatial biome migration is impossible. The three subsequent forest transitions are not evidently linked to climate events, and are suggested to be driven by internal forest dynamics. The cascade of four consecutive events of species turnover occurred at a remarkably fast rate compared to changes during the preceding and following periods, and might therefore be considered as a composite tipping point in the ecosystem. We hypothesize that wet gallery forest, spatially and temporally stabilized by the drainage system, served as a long lasting reservoir of biodiversity and facilitated a rapid exchange of species with the montane forests to allow for a rapid cascade of plant associations.

  1. Variation in Morphometric Characters in Four Sand Crab (Albunea symmysta) Populations Collected from Sumatra and Java Island, Indonesia.

    Science.gov (United States)

    Pramithasari, Febi Ayu; Butet, Nurlisa Alias; Wardiatno, Yusli

    2017-01-01

    Variation in morphometric characters in four sand crab (Albunea symmysta) populations from four intertidal areas in Sumatra (Aceh and Bengkulu) and Java (Cilacap and Yogyakarta) were studied. Crabs collected from the four sites were measured to obtain 10 morphometric characters, i.e., carapace length (CL), carapace width (CW), ocular peduncle length and width (LOP and WOP), telson length and width (LT and WT), merus length (ML), carpus length (CaL), propodus length (PL), and dactylus length (DL). Allometric relationships were established among three morphometric characters (CW, PL, and DL) for each site, in which CL was fixed on the abscissa as a reference variable. The analysis of covariance showed that population from Yogyakarta had a greater carapace width and the Aceh population had a longer dactylus length. In terms of propodus length, the Aceh population had a longer dactylus length than the Bengkulu population. Two group populations were detected by cluster analysis with 10 morphometric characters, i.e., the Sumatra population and the Java population.

  2. Angiostrongylus cantonensis Infection on Mayotte Island, Indian Ocean, 2007-2012

    Science.gov (United States)

    Epelboin, Loïc; Blondé, Renaud; Chamouine, Abdourahim; Chrisment, Alexandra; Diancourt, Laure; Villemant, Nicolas; Atale, Agnès; Cadix, Claire; Caro, Valérie; Malvy, Denis; Collet, Louis

    2016-01-01

    Introduction Human angiostrongyliasis (HA) is a neurological helminthic disease caused by the lung worm Angiostrongylus cantonensis. It is suspected in the combination of travel or a residence in an endemic area and eosinophilic meningitis. In Mayotte, an island in the Indian Ocean, cases are rare but regular. The main objective of our study was to describe the epidemiological and diagnosis clues of HA in Mayotte. The secondary objectives were to evaluate the contribution of Real-Time Polymerase Chain Reaction (RT- PCR) for the diagnosis of HA, delineate the characteristics of the local transmission and ascertain the presence of A. cantonensis in Achatina fulica, the potential vector of the disease. Materials and Methods Between 2007 and 2012, all cases of eosinophilic meningitis were retrospectively included and investigated by RT- PCR in the CSF. Descriptive analysis was conducted for clinical, biological and radiological features, and were analyzed for all patients together with the search for prognostic factors for mortality. Concurrently, geolocalization and temporal parameters were studied to correlate the occurrence of the cases with rainfall seasons and snails were collected to enhance a parasitic carriage with real time PCR. Results During the 6-year period of the study, 14 cases were identified (2.3 cases/year) and 9 among 10 remaining CSF were positive in PCR. Among 14 cases of EM, 13 were less than 2 year-old children. The 1 year mortality rate was 5/14 (35.7%). Among survivors, 3/7 (42.8%) presented neurological sequelae. Factors associated with mortality were dysfunction of cranial nerves, abnormal brain imaging, and CSF glucose level inferior to 2 mmol/l. Occurrence of cases was temporarily and spatially correlated to the rainy season. Among the 64 collected giant snails, 6 (9.4%) were positive with A. cantonensis PCR. The likely main route of transmission was the children licking snails, carriers of the parasite. Conclusion In Mayotte, HA was mainly

  3. Processing and Analysis of Near-Seafloor Magnetic Anomalies around Futuna Island, SW Pacific Ocean

    Science.gov (United States)

    Szitkar, F.; Dyment, J.; Fouquet, Y.; Choi, Y.

    2011-12-01

    In September 2010, cruise Futuna of R/V L'Atalante collected near-seafloor magnetic data with AUV Aster-X (70 m asf) and Deep-Sea Submersible (DSS) Nautile (2-20 m asf) on several volcanic systems around Futuna Island, SW Pacific Ocean. Here we present the data, the method of analysis, and a first geological interpretation. Unlike a ship, a submersible (or an AUV) cannot tow a magnetometer due to the close proximity of the seafloor. Instead, the magnetometer is rigidly fixed on the submersible, which magnetization affects the magnetic measurements. A vector magnetometer (i.e. three orthogonal fluxgate sensors) measures the field three components in a referential linked to the submarine, a requirement to determine and correct the magnetization of the submersible, The remanent magnetization vector (3 components) and the magnetic susceptibility tensor (9 coefficients) of the submersible are estimated by inverting magnetic data collected on calibration loops, far from both the ship and the seafloor, during the descent (ascent) of the submersible at the beginning (end) of the dives. For this estimation, the ambient field is assumed to be the IGRF, the departures from this assumption reflecting the magnetization of the submersible. The twelve coefficients are inverted from the loop data by a least square method, regularized by a dumping factor to account for the limited pitch and roll values sampled by the submersible. Once determined, these coefficients are used to reduce the magnetic data acquired during the whole dive for the magnetic effect of the submersible, the resulting three component anomalies being rotated to the geographic reference frame as well. The resulting anomalies acquired by the AUV on regularly-spaced tracks are gridded and reduced to the pole such as the resulting anomalies are located on the top of their causative sources. They are further inverted to equivalent magnetization using the high-resolution topography acquired by the AUV. The anomalies

  4. Depositional model of Early Permian reef-island ocean inEastern Kunlun

    Institute of Scientific and Technical Information of China (English)

    WANG; Yongbiao

    2001-01-01

    , 1982, 298 (5875): 644-647[14]Liu Benpei, Feng Qinglai, Fang Nianqiao et al., Tectonic evolution of Paleo-Tethys poly-island-ocean in Changning-Menglian and Lancangjiang belts, southwestem Yunnan, China, Earth Science (in Chinese), 1993,18(5): 529-539.

  5. Silica-poor, mafic alkaline lavas from ocean islands and continents: Petrogenetic constraints from major elements

    Indian Academy of Sciences (India)

    Shantanu Keshav; Gudmundur H Gudfinnsson

    2004-12-01

    Strongly silica-poor (ne-normative), mafic alkaline lavas generally represented by olivine nephelinites, nephelinites, melilitites, and olivine melilitites have erupted at various locations during Earth’s history. On the basis of bulk-rock Mg#, high concentrations of Na2O, TiO2, and K2O, and trace element geochemistry, it has been suggested that these lavas represent low-degree melts that have undergone little crystal fractionation en route to the surface. Many of these lavas also carry highpressure mantle material in the form of harzburgite, spinel lherzolite, and variants of websterite xenoliths, and rare garnet-bearing xenoliths. However, phenocryst phases instead indicate that these magmas cooled to variable extents during their passage. We note subtle, yet important, differences in terms of CaO, Al2O3, CaO/Al2O3, and CaO/MgO. High-pressure experimental melting studies in CMAS-CO3 (3–8GPa) and natural lherzolitic systems (3GPa) demonstrate that at an isobar increasing leads to a moderate decrease in CaO + MgO, whereas CaO/MgO and CaO/Al2O3 sharply decrease. Relatively high CaO/Al2O3 indicates melting in the presence of garnet (≥ 85km). Studies also demonstrate that CO2-bearing lherzolitic systems, when compared with anhydrous ones, also have higher CaO content in the coexisting melt at a given and . Comparison of the bulk-rock major-element chemistry of silica-poor, mafic alkaline lavas with experimentally determined high-pressure melts indicates that melting of anhydrous mantle lherzolite or garnet pyroxenite is not able to explain many of the major element systematics of the lavas. However, high-pressure partial melts of carbonated lherzolite have the right major element trends. Among ocean islands, lavas from Samoa and Hawaii are perhaps the products of very low degree of partial melting. Lavas from Gran Canaria and Polynesia represent products of more advanced partial melting. On continents, lavas from South Africa and certain localities in

  6. Bispinodinium angelaceum gen. et sp. nov. (Dinophyceae), a new sand-dwelling dinoflagellate from the seafloor off Mageshima Island, Japan(1).

    Science.gov (United States)

    Yamada, Norico; Terada, Ryuta; Tanaka, Ayumi; Horiguchi, Takeo

    2013-06-01

    A new athecate dinoflagellate, Bispinodinium angelaceum N. Yamada et Horiguchi gen. et sp. nov., is described from a sand sample collected on the seafloor at a depth of 36 m off Mageshima Island, subtropical Japan. The dinoflagellate is dorsiventrally compressed and axi-symmetric along the sulcus. The morphology resembles that of the genus Amphidinium sensu lato by having a small epicone that is less than one third of the total cell length. However, it has a new type of apical groove, the path of which traces the outline of a magnifying glass. The circular component of this path forms a complete circle in the center of the epicone and the straight "handle" runs from the sulcus to the circular component. Inside the cell, a pair of elongated fibrous structure termed here the "spinoid apparatus" extends from just beneath the circular apical groove to a point near the nucleus. Each of two paired structures consists of at least 10 hyaline fibers and this is a novel structure found in dinoflagellates. Phylogenetic analyses based on the SSU and LSU RNA genes did not show any high bootstrap affinities with currently known athecate dinoflagellates. On the basis of its novel morphological features and molecular signal, we conclude that this dinoflagellate should be described as a new species belonging to a new genus.

  7. Predation of Opuntia monacantha (Willd. Haw. (Cactaceae by Cactoblastis cactorum (Lepidoptera: Pyralidae in a sand bank area of Santa Catarina island, south Brazil

    Directory of Open Access Journals (Sweden)

    Afonso Inácio Orth

    2006-09-01

    Full Text Available The genus Opuntia is worldwide known for its ecological, ornamental and agronomic importance. Some species became pests in the countries in which they where introduced, and as biological control, Cactoblastis cactorum (Lepidoptera: Pyralidae larvae, originary from Argentina, were used. However, the effect of the attack of this piralid on native cactus has yet not been elucidated. The objective of this study was to detect and to quantify the predation of C. cactorum on Opuntia monacantha. The study was carried out from September to November of 2004, along pre-defined tracks, on a sand bank vegetation area, between the Mole and Galheta beaches in the Santa Catarina island (27º35’83.1’’S e 48º25’70.6’’W. All the studied plants (n = 20 presented some damage caused by C. cactorum. The proportion of unpredated cladodes (68% and fruits (85% was higher than the predated ones. Terminal cladodes were highly predated structures and presented the highest number of larvae inside. Seed loss in the predated fruits was high. The remaining areole of the predated cladodes and fruits differentiated into sprouts and routs and formed new plants. O. monacantha, despite of being predated by C. cactorum larvae, apparently possess defense mechanisms which assure the maintenance of its populations.

  8. Dive Data from Expedition Information System (EIS) for Islands in the Stream 2002 - Exploration of Outer Shelf and Slope Habitats off the Coast of North Carolina - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Expeditions Information System (EIS) contains information recorded by the NOAA Office of Ocean Exploration's data manager during the 2002 "Islands in the Stream...

  9. Taxonomic uncertainty and the loss of biodiversity on Christmas Island, Indian Ocean.

    Science.gov (United States)

    Eldridge, Mark D B; Meek, Paul D; Johnson, Rebecca N

    2014-04-01

    The taxonomic uniqueness of island populations is often uncertain which hinders effective prioritization for conservation. The Christmas Island shrew (Crocidura attenuata trichura) is the only member of the highly speciose eutherian family Soricidae recorded from Australia. It is currently classified as a subspecies of the Asian gray or long-tailed shrew (C. attenuata), although it was originally described as a subspecies of the southeast Asian white-toothed shrew (C. fuliginosa). The Christmas Island shrew is currently listed as endangered and has not been recorded in the wild since 1984-1985, when 2 specimens were collected after an 80-year absence. We aimed to obtain DNA sequence data for cytochrome b (cytb) from Christmas Island shrew museum specimens to determine their taxonomic affinities and to confirm the identity of the 1980s specimens. The Cytb sequences from 5, 1898 specimens and a 1985 specimen were identical. In addition, the Christmas Island shrew cytb sequence was divergent at the species level from all available Crocidura cytb sequences. Rather than a population of a widespread species, current evidence suggests the Christmas Island shrew is a critically endangered endemic species, C. trichura, and a high priority for conservation. As the decisions typically required to save declining species can be delayed or deferred if the taxonomic status of the population in question is uncertain, it is hoped that the history of the Christmas Island shrew will encourage the clarification of taxonomy to be seen as an important first step in initiating informed and effective conservation action.

  10. Quaternary geology of the Duck Hawk Bluffs, southwest Banks Island, Arctic Canada: a re-investigation of a critical terrestrial type locality for glacial and interglacial events bordering the Arctic Ocean

    Science.gov (United States)

    Evans, David J. A.; England, John H.; La Farge, Catherine; Coulthard, Roy D.; Lakeman, Thomas R.; Vaughan, Jessica M.

    2014-05-01

    Duck Hawk Bluffs, southwest Banks Island, is a primary section (8 km long and 60 m high) in the western Canadian Arctic Archipelago exposing a long record of Quaternary sedimentation adjacent to the Arctic Ocean. A reinvestigation of Duck Hawk Bluffs demonstrates that it is a previously unrecognized thrust-block moraine emplaced from the northeast by Laurentide ice. Previous stratigraphic models of Duck Hawk Bluffs reported a basal unit of preglacial fluvial sand and gravel (Beaufort Fm, forested Arctic), overlain by a succession of three glaciations and at least two interglacials. Our observations dismiss the occurrence of preglacial sediments and amalgamate the entire record into three glacial intervals and one prominent interglacial. The first glacigenic sedimentation is recorded by an ice-contact sandur containing redeposited allochthonous organics previously assigned to the Beaufort Fm. This is overlain by fine-grained sediments with ice wedge pseudomorphs and well-preserved bryophyte assemblages corresponding to an interglacial environment similar to modern. The second glacial interval is recorded by ice-proximal mass flows and marine rhythmites that were glacitectonized when Laurentide ice overrode the site from Amundsen Gulf to the south. Sediments of this interval have been reported to be magnetically reversed (>780 ka). The third interval of glacigenic sedimentation includes glacifluvial sand and gravel recording the arrival of Laurentide ice that overrode the site from the northeast (island interior) depositing a glacitectonite and constructing the thrust block moraine that comprises Duck Hawk Bluffs. Sediments of this interval have been reported to be magnetically normal (ice from the interior of Banks Island coalesced with an ice stream in Amundsen Gulf, depositing the interlobate Sachs Moraine that contains shells as young as ˜24 cal ka BP (Late Wisconsinan). During deglaciation, meltwater emanating from these separating ice lobes deposited outwash

  11. Evolution of an oceanic anticyclone in the lee of Madeira Island: In situ and remote sensing survey

    Science.gov (United States)

    Caldeira, Rui M. A.; Stegner, Alexandre; Couvelard, Xavier; Araújo, Isabel B.; Testor, Pierre; Lorenzo, Alvaro

    2014-02-01

    Island wakes are areas of a strong eddy activity influencing the availability and transport of organic matter in the ocean which, in turn impact biological productivity. Despite this, eddy formation in the lee of North Atlantic tropical islands is scarcely documented, except for the Canary Islands. Moreover, the occurrence of anticyclones leeward of Madeira has seldom been detected. During the summer of 2011, a multiplatform approach, combining satellite data with in situ measurements, was used to study an anticyclonic eddy generated in the lee of the Madeira Island. The main objective was to confirm recent numerical evidence suggesting that orographically perturbed winds can induce anticyclonic eddies leeward of Madeira, particularly during summer months. The high resolution sampling of the eddy's interior shows a strong downwelling of ≈100 m of the isopycnal layer below the mixed layer, typical of intrathermocline eddies. The 25 km radius of this anticyclonic structure exceeds the local deformation radius by a factor of 2. The vortex Rossby number remained moderate (Ro = 0.26) even if the relative core vorticity reached a finite value (ζ/f = -0.7). The occurrence of strong trade winds (10-15 m s-1) prior to the detection of the first surface eddy signatures (July 2011) concurrent with opposite flowing geostrophic currents, shows that the orographic wind forcing is the main mechanism for generating this mesoscale long-lived eddy. After leaving the shelter of the island, the eddy traveled northwesterly following a perpendicular net Ekman transport pathway at a speed of 5 km/d, for at least 2 months. An interaction with a cyclonic partner generated in the area helped precipitate the northward trajectory. This study presents the first clear evidence of a wind-induced mesoscale anticyclone in the lee of Madeira.

  12. Time-space variability of satellite chlorophyll-α in the Easter Island Province, southeastern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Isabel Andrade

    2014-10-01

    Full Text Available The Easter Island Province (EIP encompasses Easter Island (EI and Salas y Gómez Island (SGI, which are located in the eastern boundary of the south Pacific subtropical gyre. This province is one of the most oligotrophic region in the world ocean with a high degree of endemism and distinguished by having the clearest waters in the world. Issues related to the biophysical coupling that sustains biological production in this region are still poorly understood. Satellite data compiled over a ten year period was used to characterize the spatial and temporal chlorophyll-α (Chl-α variability around the EIP and determine the relationship between Chl-α and several physical forcing. Results shows a clear Chl-α annual cycle around the EIP, with maximum concentration during the austral winter. Chl-α spatial distribution shows a strong zonal dipole over EI that divides the island into two zones: southeast and northwest. Due to its small size and low elevation of SGI, it does not generate a significant local effect in Chl-α concentration, but a Chl-α increase is observed southeast of this island (~2 km associated to a seamount. The mean geostrophic current in the EIP flows eastward, associated with the southeastern boundary of the subtropical gyre. However, recurrent mesoscale eddies traveling northwestward and produce large surface current variability with periods of high velocities in opposite direction. In the spring, wakes of high Chl-α concentration can be observed over EI, associated with the generation and detachment of submesoscale eddies from EI, which could have important biological implications during periods of low regional biological production.

  13. Bivergent thrust wedges surrounding oceanic island arcs: Insight from observations and sandbox models of the northeastern caribbean plate

    Science.gov (United States)

    ten Brink, U.S.; Marshak, S.; Granja, Bruna J. L.

    2009-01-01

    At several localities around the world, thrust belts have developed on both sides of oceanic island arcs (e.g., Java-Timor, Panama, Vanuatu, and the northeastern Caribbean). In these localities, the overall vergence of the backarc thrust belt is opposite to that of the forearc thrust belt. For example, in the northeastern Caribbean, a north-verging accretionary prism lies to the north of the Eastern Greater Antilles arc (Hispaniola and Puerto Rico), whereas a south-verging thrust belt called the Muertos thrust belt lies to the south. Researchers have attributed such bivergent geometry to several processes, including: reversal of subduction polarity; subduction-driven mantle flow; stress transmission across the arc; gravitational spreading of the arc; and magmatic inflation within the arc. New observations of deformational features in the Muertos thrust belt and of fault geometries produced in sandbox kinematic models, along with examination of published studies of island arcs, lead to the conclusion that the bivergence of thrusting in island arcs can develop without reversal of subduction polarity, without subarc mantle flow, and without magmatic inflation. We suggest that the Eastern Greater Antilles arc and comparable arcs are simply crustalscale bivergent (or "doubly vergent") thrust wedges formed during unidirectional subduction. Sandbox kinematic modeling suggests, in addition, that a broad retrowedge containing an imbricate fan of thrusts develops only where the arc behaves relatively rigidly. In such cases, the arc acts as a backstop that transmits compressive stress into the backarc region. Further, modeling shows that when arcs behave as rigid blocks, the strike-slip component of oblique convergence is accommodated entirely within the prowedge and the arc-the retrowedge hosts only dip-slip faulting ("frontal thrusting"). The existence of large retrowedges and the distribution of faulting in an island arc may, therefore, be evidence that the arc is

  14. 78 FR 76060 - Pacific Ocean off the Pacific Missile Range Facility at Barking Sands, Island of Kauai, Hawaii...

    Science.gov (United States)

    2013-12-16

    ... amendment to the regulation will not have a significant impact to the quality of the human environment and... activities, increases in force protection and other mission-essential evolutions without first obtaining...-essential evolutions. Residents and visitors who typically use these waters off Pacific Missile...

  15. 78 FR 39198 - Pacific Ocean Off the Pacific Missile Range Facility at Barking Sands, Island of Kauai, Hawaii...

    Science.gov (United States)

    2013-07-01

    ... this regulation, if adopted, will not have a significant impact to the quality of the human environment... evolutions. The expanded danger zone would extend along approximately seven miles of shoreline adjacent to... activities, increases in force protection and other mission essential evolutions. The expanded danger...

  16. Archean hydrothermal oceanic floor sedimentary environments: DXCL drilling project of the 3.2 Ga Dixon Island Formation, Pilbara, Australia

    Science.gov (United States)

    Kiyokawa, S.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Naraoka, H.; Sakamoto, R.; Suganuma, Y.

    2009-12-01

    Many place in Archean greenstone belts have been reported of the black chert to Iron rich sediments above volcanic sequence. The chemical sedimentary sequence has been recognized to form by as hydrothermal siliceous sequence. These sediments contain the hint to understand the Archean ocean and earth surface environments. Here, we will focus the Dixon Island and Cleaverville formations, which are one of the best preserved Archean hydrothermal sedimentary sequence in the world, to recognized detail stratigraphy and restored deep ocean environment. We did scientific drilling, which is called ‘DXCL drilling project’, at 2007 summer. This drilling project had been selected two coastal sites; CL site at lower part of the Cleaverville Formation, and another is DX site at the upper Dixon Island Formation. A systematic combinations of geological, sedimentological, geochemical, and geobiological approaches will be applied to the fresh samples. Here we will show the recent result of this sequence, which will be key evidence to understand the nature of the middle Archean (3.2 Ga) marine environment influenced by hydrothermal activity. The 3.2 Ga Dixon Island -Cleaverville formations composed of volcanic rock units and chemical-volcanosedimentary sequence which are identified by accreted immature island arc setting. The ~350m-thick Dixon Island Formation which is overlie by pillow basalt consists mainly of highly silicified volcanic-siliceous sequences that contain apparent microbial mats and bacterial fossil-like structure within black chert and also includes a komatiite-rhyolite sequences bearing hydrothermal veins. The >300m-thick Cleaverville Formation, which conformably overlay pillow basalt, contains a thick unit of reddish shale, bedded red-white chert and banded iron formation. It partly contains chert fragments-bearing pyroclastic beds. In detail lithology from the drill cores, the CL and DX contain different type of organic rocks. The CL 1 and CL2 core samples

  17. Magnetic Anomaly Modeling of Volcanic Structure and Stratigraphy - Socorro Island, Eastern Pacific Ocean

    Science.gov (United States)

    Urrutia-Fucugauchi, Jaime; Escorza-Reyes, Marisol; Pavon-Moreno, Julio; Perez-Cruz, Ligia; Sanchez-Zamora, Osvaldo

    2013-04-01

    Results of a magnetic survey of the volcanic structure of Socorro Island in the Revillagigedo Archipielago are presented. Socorro is part of a group of seamounts and oceanic islands built by volcanic activity at the northern end of the Mathematician ridge and intersection with the Clarion and Rivera fracture zones. Subaerial volcanic activity is characterized by alkaline and peralkaline compositions, marked by pre-, syn- and post-caldera phases of the Evermann volcano, and the Holocene mafic activity of the Lomas Coloradas. The magnetic survey conducted in the central-southern sector of the island permits to investigate the volcanic structure and subsurface stratigraphy. Regional fields for second- and third-degree polynomials show a magnetic low over the caldera, positive anomalies above the pre-caldera deposits and intermediate amplitude anomalies over Lomas Coloradas. Residual fields delineate the structural rim of the caldera, anomaly trends for the pre- and post-caldera deposits and a broad anomaly over Lomas Coloradas. Regional-residual anomalies, first vertical derivative, analytical upward and downward continuations, and forward four-layer modeling are used to construct the geophysical models. Rock magnetic properties were analyzed on samples collected at 24 different sites. Magnetic susceptibility showed wide range of variation from ~10 to ~500 10-3 SI, corresponding to the different lithologies from trachytes and glass-rich tuffs to alkali basalts. Data have been divided into groups with low, intermediate and high values. Rock magnetic analyses indicate that magnetite and titanomagnetites are the main magnetization carriers. Magnetic hysteresis loops indicate low coercivity minerals, with high saturation and remanent magnetizations and PSD domain states. Magnetic susceptibility versus temperature curves show irreversible behavior with Curie temperatures around 560-575 C, suggesting magnetite and Ti-poor titanomagnetites. Paleomagnetic directions

  18. Thickness of the oceanic crust and the mantle transition zone in the vicinity of the Tristan da Cunha hot spot estimated from ocean-bottom and ocean-island seismometer receiver functions

    Science.gov (United States)

    Geissler, Wolfram; Jokat, Wilfried; Jegen, Marion; Baba, Kiyoshi

    2016-04-01

    According to classical plume theory, the Tristan da Cunha hotspot is thought to have played a major role in the rifting of the South Atlantic margins and the creation of the aseismic Walvis Ridge by impinging at the base of the continental lithosphere shortly before or during the breakup of the South Atlantic margins. However, Tristan da Cunha is enigmatic as it cannot be clearly identified as a hot spot but may also be classified as a more shallow type of anomaly that may actually have been caused by the opening of the South Atlantic. The equivocal character of Tristan da Cunha is largely due to a lack of geophysical and petrological data in this region. We therefore staged a multi-disciplinary geophysical study of the region by acquiring passive marine electromagnetic and seismic data, and bathymetric data within the framework of the SPP1375 South Atlantic Margin Processes and Links with onshore Evolution (SAMPLE) funded by the German Science foundation. The experiment included two ship expeditions onboard the German R/V MARIA S. MERIAN in 2012 and 2013. In our contribution we will present results on the thickness of the oceanic crust in the vicinity of the Tristan da Cunha archipelago derived from ocean-bottom seismometer data. Using the Ps receiver function method we estimate a thickness of 5 to 7 km for the oceanic crust at 17 ocean-bottom stations surrounding the islands in an area where the ocean floor has an age of approximately 10 to 30 Ma (from west to east). This indicates normal to slightly lowered magmatic activity at the mid-ocean ridge during the crust formation. There seems to be no major contribution of a mantle plume to the melting conditions at the ridge, which should cause the formation of thickened oceanic crust. The magmatic activity at the archipelago and surrounding seamounts seems to have only local effects on the crustal thickness. Furthermore, we imaged the mantle transition zone discontinuities analysing receiver functions at the

  19. Evolution, insular restriction, and extinction of oceanic land crabs, exemplified by the loss of an endemic Geograpsus in the Hawaiian Islands.

    Science.gov (United States)

    Paulay, Gustav; Starmer, John

    2011-01-01

    Most oceanic islands harbor unusual and vulnerable biotas as a result of isolation. As many groups, including dominant competitors and predators, have not naturally reached remote islands, others were less constrained to evolve novel adaptations and invade adaptive zones occupied by other taxa on continents. Land crabs are an excellent example of such ecological release, and some crab lineages made the macro-evolutionary transition from sea to land on islands. Numerous land crabs are restricted to, although widespread among, oceanic islands, where they can be keystone species in coastal forests, occupying guilds filled by vertebrates on continents. In the remote Hawaiian Islands, land crabs are strikingly absent. Here we show that absence of land crabs in the Hawaiian Islands is the result of extinction, rather than dispersal limitation. Analysis of fossil remains from all major islands show that an endemic Geograpsus was abundant before human colonization, grew larger than any congener, and extended further inland and to higher elevation than other land crabs in Oceania. Land crabs are major predators of nesting sea birds, invertebrates and plants, affect seed dispersal, control litter decomposition, and are important in nutrient cycling; their removal can lead to large-scale shifts in ecological communities. Although the importance of land crabs is obvious on remote and relatively undisturbed islands, it is less apparent on others, likely because they are decimated by humans and introduced biota. The loss of Geograpsus and potentially other land crabs likely had profound consequences for Hawaiian ecosystems.

  20. Surficial geology of the sea floor in Long Island Sound offshore of Plum Island, New York

    Science.gov (United States)

    McMullen, K.Y.; Poppe, L.J.; Danforth, W.W.; Blackwood, D.S.; Schaer, J.D.; Ostapenko, A.J.; Glomb, K.A.; Doran, E.F.

    2010-01-01

    The U.S. Geological Survey (USGS), the Connecticut Department of Environmental Protection, and the National Oceanic and Atmospheric Administration (NOAA) have been working cooperatively to interpret surficial sea-floor geology along the coast of the Northeastern United States. NOAA survey H11445 in eastern Long Island Sound, offshore of Plum Island, New York, covers an area of about 12 square kilometers. Multibeam bathymetry and sidescan-sonar imagery from the survey, as well as sediment and photographic data from 13 stations occupied during a USGS verification cruise are used to delineate sea-floor features and characterize the environment. Bathymetry gradually deepens offshore to over 100 meters in a depression in the northwest part of the study area and reaches 60 meters in Plum Gut, a channel between Plum Island and Orient Point. Sand waves are present on a shoal north of Plum Island and in several smaller areas around the basin. Sand-wave asymmetry indicates that counter-clockwise net sediment transport maintains the shoal. Sand is prevalent where there is low backscatter in the sidescan-sonar imagery. Gravel and boulder areas are submerged lag deposits produced from the Harbor Hill-Orient Point-Fishers Island moraine segment and are found adjacent to the shorelines and just north of Plum Island, where high backscatter is present in the sidescan-sonar imagery.

  1. Chemical evolution at the coasts of active volcanic islands in a primordial salty ocean

    Science.gov (United States)

    Strasdeit, H.; Fox, S.

    2008-09-01

    The Prebiotic Hot-Volcanic-Coast Scenario It has been suggested that in the Hadean eon (4.5-3.8 Ga before present) no permanent continents but volcanic islands and short-lived protocontinents protruded from the first ocean [1, 2]. As the geothermal heat production was considerably higher than today, it is reasonable to assume that hot volcanic coasts were much more abundant. The salinity of the ocean was probably up to two times higher than the modern value [3]. Under these conditions, the evaporation of seawater at active volcanic coasts must have produced sea salt crusts - a process that can still be observed today [4]. On the hot lava rock, the salt crusts can subsequently experience temperatures up to some hundred degrees Celsius. The seawater probably contained abiotically formed organic molecules such as amino acids, which were inevitably embedded into the sea salt crusts. Different prebiotic sources of amino acids have been discussed: (i) comets and meteorites [5], electrical discharges in the atmosphere [6, 7], and deep-sea hydrothermal vents [8]. We undertook a systematic study of solid salt-amino acid mixtures, especially of their formation and thermal behavior under simulated conditions of the hotvolcanic- coast scenario. Laboratory Experiments Amino acids@salts Artificial Hadean seawater was prepared by dissolving NaCl (705 mmol), MgCl2 (80 mmol), KCl (15 mmol), CaCl2 (15 mmol), and an α-amino acid (5-10 mmol) or a mixture of α-amino acids. In order to model the first step of the hot-volcanic-coast scenario, the solutions were evaporated to dryness. Vibrational spectroscopy (IR, Raman) and X-ray powder diffraction showed that the resulting solid residues were not heterogeneous mixtures of salt and amino acid crystals. Instead the amino acid molecules were coordinated in calcium or magnesium complexes. We have studied the rac-alanine ( + H3NCH(CH3)COO -, Hala) system in more detail and found that the complex that is present in the mixture has the

  2. Evaluation of dredged material proposed for ocean disposal from South Brother Island Channel, New York

    Energy Technology Data Exchange (ETDEWEB)

    Barrows, E.S.; Gardiner, W.W.; Antrim, L.D.; Gruendell, B.D.; Word, J.Q.; Tokos, J.J.S. [Battelle Marine Sciences Laboratory, Sequim, Washington (United States)

    1996-09-01

    South Brother Island Channel was one of seven waterways that the US Army Crops of Engineers-New York District requested the Battelle/Marine Sciences Laboratory to sample and evaluate for dredging and disposal. Tests and analyses were conducted on South Brother Island Channel sediment core samples and evaluations were performed. The evaluation of proposed dredged material from South Brother Island Channel included bulk sediment chemical analyses, chemical analyses of site water and elutriate, water-column and benthic acute toxicity tests, and bioaccumulation studies. Individual sediment core samples collected from Souther Brother Island Channel were analyzed for grain size, moisture content, and total organic carbon. a composite sediment sample, representing the entire area proposed for dredging, was analyzed for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl congers, polynuclear aromatic hydrocarbons, and 1,4- dichlorobenzene. Site water and elutriate water, prepared from the suspended-particle phase of South Brother Island Channel sediment, were analyzed for metals, pesticides, and PCBs.

  3. Rising oceans, climate change, food aid, and human rights in the Marshall Islands.

    Science.gov (United States)

    Ahlgren, Ingrid; Yamada, Seiji; Wong, Allen

    2014-01-01

    Climate change impacts are expected to produce more frequent, longer and unpredictable drought periods with further saltwater intrusion in the Marshall Islands. As a result, a significant return to traditional food cropping is unlikely. This will lead to an increased dependence on food aid, especially in the outer atoll populations. An examination of the nutritional content of food aid suggests it is likely to lead to poor health outcomes. Dependence on food aid has gradually increased over the past 70 years in the Marshall Islands, starting with population relocation because of war and nuclear testing and most recently because of climate change. The authors argue that the health impacts of the supplemental imported diet, combined with migration to population centers, may result in an even greater prevalence of chronic diseases, and exert pressures that lead to more communicable disease, further exacerbating the syndemics in the Marshall Islands. The authors conclude that food aid donors and the Republic of the Marshall Islands (RMI) government have human rights obligations to ensure that the people in the Marshall Islands have access to adequate nutrition. Accordingly, donors and the government should re-examine the content of food and ensure it is of sufficient quality to meet the right to health obligations.

  4. Functional biogeography of oceanic islands and the scaling of functional diversity in the Azores.

    Science.gov (United States)

    Whittaker, Robert J; Rigal, François; Borges, Paulo A V; Cardoso, Pedro; Terzopoulou, Sofia; Casanoves, Fernando; Pla, Laura; Guilhaumon, François; Ladle, Richard J; Triantis, Kostas A

    2014-09-23

    Analyses of species-diversity patterns of remote islands have been crucial to the development of biogeographic theory, yet little is known about corresponding patterns in functional traits on islands and how, for example, they may be affected by the introduction of exotic species. We collated trait data for spiders and beetles and used a functional diversity index (FRic) to test for nonrandomness in the contribution of endemic, other native (also combined as indigenous), and exotic species to functional-trait space across the nine islands of the Azores. In general, for both taxa and for each distributional category, functional diversity increases with species richness, which, in turn scales with island area. Null simulations support the hypothesis that each distributional group contributes to functional diversity in proportion to their species richness. Exotic spiders have added novel trait space to a greater degree than have exotic beetles, likely indicating greater impact of the reduction of immigration filters and/or differential historical losses of indigenous species. Analyses of species occurring in native-forest remnants provide limited indications of the operation of habitat filtering of exotics for three islands, but only for beetles. Although the general linear (not saturating) pattern of trait-space increase with richness of exotics suggests an ongoing process of functional enrichment and accommodation, further work is urgently needed to determine how estimates of extinction debt of indigenous species should be adjusted in the light of these findings.

  5. Seven new species of Paleanotus (Annelida: Chrysopetalidae) described from Lizard Island, Great Barrier Reef, and coral reefs of northern Australia and the Indo-Pacific: two cryptic species pairs revealed between western Pacific Ocean and the eastern Indian Ocean.

    Science.gov (United States)

    Watson, Charlotte

    2015-09-18

    Morphological investigation into the paleate genus Paleanotus Schmarda 1861 of the family Chrysopetalidae from northern Australian coral reefs, primarily Lizard Island and outlying reefs, included a complex of very small, slender individuals (length Great Barrier Reef to the Philippines, western Pacific Ocean. Cryptic morphology and potential genetic diversity is discussed in Paleanotus inornatus n. sp. and P. adornatus n. sp. that possess overlapping widespread distribution patterns across northern Australia and Indo-Pacific reefs. The smallest bodied taxon, Paleanotus chrysos n. sp. is the only species with a Coral Sea range encompassing Lizard Island, Heron Island and New Caledonia.

  6. A high-resolution, absolute-dated deglacial speleothem record of Indian Ocean climate from Socotra Island, Yemen

    Science.gov (United States)

    Shakun, Jeremy D.; Burns, Stephen J.; Fleitmann, Dominik; Kramers, Jan; Matter, Albert; Al-Subary, Abdulkarim

    2007-07-01

    Stalagmite M1-5 from Socotra Island, Yemen in the northwest Indian Ocean provides a robust, high-resolution paleoclimate record from ˜ 27.4-11.1 ka based on 717 stable isotope and 28 230Th measurements. Variations in M1-5 oxygen isotope ratios ( δ18O) are interpreted to be primarily driven by an amount effect related to changes in the mean position and/or intensity of convection of the intertropical convergence zone, the island's only source of precipitation. The M1-5 δ18O time series is strongly correlated to the Greenland ice cores, similar to an older Socotra speleothem deposited from 53-40 ka [S.J. Burns, D. Fleitmann, A. Matter, J. Kramers, A. Al-Subbary, Indian Ocean climate and an absolute chronology over Dansgaard/Oeschger events 9 to 13, Science 301 (2003) 1365-1367], indicating that a North Atlantic-Indian Ocean cold-dry/warm-wet teleconnection persisted through the end of the last glacial period. Peak aridification occurred at ˜ 23 ka and a gradual increase in moisture thereafter was interrupted by an abrupt drying event at ˜ 16.4 ka, perhaps related to Heinrich event 1. Indian Ocean rainfall increased dramatically during the Bølling period and then decreased continuously and gradually through the Allerød and Younger Dryas. The Holocene began abruptly with increased precipitation at 11.4 ka and was followed by a major but short-lived drying during the Preboreal Oscillation at ˜ 11.2 ka. M1-5 is highly correlated to the Dongge Cave record from 15.5-11 ka, suggesting much of the Indian Ocean monsoon region responded similarly to the major climate changes of the last deglaciation. The transitions into the Younger Dryas and to a lesser extent the Bølling are remarkably gradual in M1-5, as they are in all other Asian speleothem records, occurring over several centuries. These gradual transitions are in striking contrast to high-resolution records from around the North Atlantic basin where the transitions are extremely abrupt and generally occur in

  7. Penguins as bioindicators of mercury contamination in the Southern Ocean: Birds from the Kerguelen Islands as a case study

    Energy Technology Data Exchange (ETDEWEB)

    Carravieri, Alice, E-mail: carravieri@cebc.cnrs.fr [Centre d' Etudes Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, BP 14, 79360 Villiers-en-Bois (France); Littoral Environnement et Sociétés (LIENSs), UMRi 7266 CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Bustamante, Paco, E-mail: pbustama@univ-lr.fr [Littoral Environnement et Sociétés (LIENSs), UMRi 7266 CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Churlaud, Carine [Littoral Environnement et Sociétés (LIENSs), UMRi 7266 CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Cherel, Yves [Centre d' Etudes Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, BP 14, 79360 Villiers-en-Bois (France)

    2013-06-01

    Seabirds have been used extensively as bioindicators of mercury (Hg) contamination in the marine environment, although information on flightless species like penguins remains limited. In order to assess the use of penguins as bioindicators of Hg contamination in subantarctic and Antarctic marine ecosystems, Hg concentrations were evaluated in the feathers of the four species that breed on the Kerguelen Islands in the southern Indian Ocean. Compared to other seabirds, adult Kerguelen penguins had low to moderate feather Hg concentrations, with an average ranging from 1.96 ± 0.41 μg g{sup −1} dry weight in the southern rockhopper penguin to 5.85 ± 3.00 μg g{sup −1} dry weight in the gentoo penguin. The species was a major determinant of Hg contamination, with feather Hg concentrations being lower in the oceanic species (king and crested penguins) than in the coastal one (gentoo penguin). In all species however, feather Hg concentrations were higher in adults than in chicks, reflecting the different periods of Hg bioaccumulation in the internal tissues of the two age classes. The relationship between adult penguin trophic ecology and Hg burdens was investigated using stable isotopes. Feeding habits (reflected by δ{sup 15}N values) had a greater effect on adult feather Hg concentrations when compared to foraging habitats (reflected by δ{sup 13}C values), indicating Hg biomagnification in Kerguelen neritic and oceanic waters. Dietary preferences were crucial in explaining individual feather Hg concentrations, as highlighted by intra-specific variation in Hg levels of gentoo penguins sampled at two different breeding sites of the archipelago. Penguins appear to reflect Hg bioavailability reliably in their foraging environment and could serve as efficient bioindicators of Hg contamination in the Southern Ocean on different spatial and temporal scales. - Highlights: • Hg contamination was evaluated in 4 species of penguins at the Kerguelen Islands. • Adults

  8. Development of Automated Whistle and Click Classifiers for Odontocete Species in the Western Atlantic Ocean and the Waters Surrounding the Hawaiian Islands

    Science.gov (United States)

    2015-09-30

    task, feature vectors will be created using visually validated, single species acoustic recordings collected in the northwest Atlantic Ocean, the...for Odontocete Species in the Western Atlantic Ocean and the Waters Surrounding the Hawaiian Islands Julie N. Oswald & Tina M. Yack Bio- Waves ...information about acoustic encounters. 2. Examine geographic variation in the characteristics of whistles and clicks produced by species that are found in

  9. Tsunami Hazard in La Réunion Island (SW Indian Ocean): Scenario-Based Numerical Modelling on Vulnerable Coastal Sites

    Science.gov (United States)

    Allgeyer, S.; Quentel, É.; Hébert, H.; Gailler, A.; Loevenbruck, A.

    2017-08-01

    Several major tsunamis have affected the southwest Indian Ocean area since the 2004 Sumatra event, and some of them (2005, 2006, 2007 and 2010) have hit La Réunion Island in the southwest Indian Ocean. However, tsunami hazard is not well defined for La Réunion Island where vulnerable coastlines can be exposed. This study offers a first tsunami hazard assesment for La Réunion Island. We first review the historical tsunami observations made on the coastlines, where high tsunami waves (2-3 m) have been reported on the western coast, especially during the 2004 Indian Ocean tsunami. Numerical models of historical scenarios yield results consistent with available observations on the coastal sites (the harbours of La Pointe des Galets and Saint-Paul). The 1833 Pagai earthquake and tsunami can be considered as the worst-case historical scenario for this area. In a second step, we assess the tsunami exposure by covering the major subduction zones with syntethic events of constant magnitude (8.7, 9.0 and 9.3). The aggregation of magnitude 8.7 scenarios all generate strong currents in the harbours (3-7 m s^{-1}) and about 2 m of tsunami maximum height without significant inundation. The analysis of the magnitude 9.0 events confirms that the main commercial harbour (Port Est) is more vulnerable than Port Ouest and that flooding in Saint-Paul is limited to the beach area and the river mouth. Finally, the magnitude 9.3 scenarios show limited inundations close to the beach and in the riverbed in Saint-Paul. More generally, the results confirm that for La Runion, the Sumatra subduction zone is the most threatening non-local source area for tsunami generation. This study also shows that far-field coastal sites should be prepared for tsunami hazard and that further work is needed to improve operational warning procedures. Forecast methods should be developed to provide tools to enable the authorities to anticipate the local effects of tsunamis and to evacuate the harbours in

  10. Five new extinct species of rails (Aves: Gruiformes: Rallidae) from the Macaronesian Islands (North Atlantic Ocean).

    Science.gov (United States)

    Alcover, Josep Antoni; Pieper, Harald; Pereira, Fernando; Rando, Juan Carlos

    2015-12-10

    Five new species of recently extinct rails from two Macaronesian archipelagoes (Madeira and Azores) are described. All the species are smaller in size than their presumed ancestor, the European rail Rallus aquaticus. Two species inhabited the Madeira archipelago: (1) Rallus lowei n. sp., the stouter of the species described herein, was a flightless rail with a robust tarsometatarsus and reduced wings that lived on Madeira Island; (2) Rallus adolfocaesaris n. sp., a flightless and more gracile species than its Madeiran counterpart, inhabited Porto Santo. So far, six Azorean islands have been paleontologically explored, and the remains of fossil rails have been found on all of them. Here we formally describe the best-preserved remains from three islands (Pico, São Miguel and São Jorge): (1) Rallus montivagorum n. sp., a rail smaller than R. aquaticus with a somewhat reduced flying capability, inhabited Pico; (2) Rallus carvaoensis n. sp., a small flightless rail with short and stout legs and a bill apparently more curved than in R. aquaticus, was restricted to São Miguel; (3) Rallus minutus n. sp., a very small (approaching Atlantisia rogersi in size) flightless rail with a shortened robust tarsometatarsus, lived in São Jorge. We note also the presence of rail fossils on three other Azorean islands (Terceira, Graciosa and Santa Maria). In addition, we describe an extraordinarily complete fossil of an unnamed Rallus preserved in silica from the locality of Algar do Carvão on Terceira.

  11. Rickettsia spp. in seabird ticks from western Indian Ocean islands, 2011-2012.

    Science.gov (United States)

    Dietrich, Muriel; Lebarbenchon, Camille; Jaeger, Audrey; Le Rouzic, Céline; Bastien, Matthieu; Lagadec, Erwan; McCoy, Karen D; Pascalis, Hervé; Le Corre, Matthieu; Dellagi, Koussay; Tortosa, Pablo

    2014-05-01

    We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.

  12. 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

  13. Cascading effects of predation risk determine how marine predators become terrestrial prey on an oceanic island.

    Science.gov (United States)

    Thomsen, Sarah K; Green, David J

    2016-12-01

    Apex predators can suppress the foraging activity of mesopredators, which may then result in cascading benefits for the prey of those mesopredators. We studied the interactions between a top predator, the Barn Owl (Tyto alba), and their primary prey, an island endemic deer mouse (Peromyscus maniculatus elusus), which in turn consumes the eggs of seabirds nesting on Santa Barbara Island in California. Scripps's Murrelets (Synthliboramphus scrippsi), a threatened nocturnal seabird, arrive annually to breed on this island, and whose first egg is particularly vulnerable to predation by mice. We took advantage of naturally occurring extreme variations in the density of mice and owls on the island over 3 years and predicted that (1) mouse foraging would decrease with increasing predation risk from owls and moonlight and (2) these decreases in foraging would reduce predation on murrelet eggs. We measured the giving up densities of mice with experimental foraging stations and found that mice were sensitive to predation risk and foraged less when owls were more abundant and less during the full moon compared to the new moon. We also monitored the fates of 151 murrelet eggs, and found that murrelet egg predation declined as owl abundance increased, and was lower during the full moon compared to the new moon. Moreover, high owl abundance suppressed egg predation even when mice were extremely abundant. We conclude that there is a behaviorally mediated cascade such that owls on the island had a positive indirect effect on murrelet egg survival. Our study adds to the wider recognition of the strength of risk effects to structure food webs, as well as highlighting the complex ways that marine and terrestrial food webs can intersect. © 2016 by the Ecological Society of America.

  14. Penguins as bioindicators of mercury contamination in the Southern Ocean: birds from the Kerguelen Islands as a case study.

    Science.gov (United States)

    Carravieri, Alice; Bustamante, Paco; Churlaud, Carine; Cherel, Yves

    2013-06-01

    Seabirds have been used extensively as bioindicators of mercury (Hg) contamination in the marine environment, although information on flightless species like penguins remains limited. In order to assess the use of penguins as bioindicators of Hg contamination in subantarctic and Antarctic marine ecosystems, Hg concentrations were evaluated in the feathers of the four species that breed on the Kerguelen Islands in the southern Indian Ocean. Compared to other seabirds, adult Kerguelen penguins had low to moderate feather Hg concentrations, with an average ranging from 1.96 ± 0.41 μgg(-1) dry weight in the southern rockhopper penguin to 5.85 ± 3.00 μg g(-1) dry weight in the gentoo penguin. The species was a major determinant of Hg contamination, with feather Hg concentrations being lower in the oceanic species (king and crested penguins) than in the coastal one (gentoo penguin). In all species however, feather Hg concentrations were higher in adults than in chicks, reflecting the different periods of Hg bioaccumulation in the internal tissues of the two age classes. The relationship between adult penguin trophic ecology and Hg burdens was investigated using stable isotopes. Feeding habits (reflected by δ(15)N values) had a greater effect on adult feather Hg concentrations when compared to foraging habitats (reflected by δ(13)C values), indicating Hg biomagnification in Kerguelen neritic and oceanic waters. Dietary preferences were crucial in explaining individual feather Hg concentrations, as highlighted by intra-specific variation in Hg levels of gentoo penguins sampled at two different breeding sites of the archipelago. Penguins appear to reflect Hg bioavailability reliably in their foraging environment and could serve as efficient bioindicators of Hg contamination in the Southern Ocean on different spatial and temporal scales. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Survival of a native mammalian carnivore, the leopard cat Prionailurus bengalensis Kerr, 1792 (Carnivora: Felidae, in an agricultural landscape on an oceanic Philippine island

    Directory of Open Access Journals (Sweden)

    M.R.P. Lorica

    2013-06-01

    Full Text Available Concerns about vulnerability of mammalian carnivores to extinction, especially on small islands, appear to conflict with prior reports of endemic populations of leopard cat Prionailurus bengalensis (Kerr, 1792 surviving in agricultural landscapes on oceanic islands. We investigated the persistence of the Visayan leopard cat (P. b. rabori in the sugarcane fields on Negros, an oceanic island in central Philippines. A population remained throughout the year at our study site on a sugarcane farm, and reproduction was noted. Non-native rodents form the bulk of the cat diet, followed by reptiles, birds, amphibians, and insects. Prey species identified from the samples commonly occur in agricultural areas in the Philippines. Prey composition did not vary significantly with respect to wet and dry season, or sugarcane harvest cycle. This study provides evidence that an intensively managed agricultural landscape on this oceanic island supports a native obligate carnivore that subsists primarily on exotic rats. This study supports a prior prediction that leopard cats will show flexibility in prey selection on islands with few or no native small mammal prey species, but in this case they do so not by switching to other vertebrates and invertebrates, but rather to exotic pest species of rodents.

  16. Aspirations and Tensions in Developing International Mindedness: Case Study of Two Students in an IB School in an Indian Ocean Island Nation

    Science.gov (United States)

    Poonoosamy, Mico

    2016-01-01

    International mindedness is considered by many educational researchers and organizations as a determining feature in international education. This article used data as part of a PhD case study inquiry to explore how international mindedness is developed by two students in an IB school in an Indian Ocean Island Nation. Through a qualitative…

  17. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  18. 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.

  19. Dracograllus trukensis sp. nov. (Draconematidae: Nematoda) from a seagrass bed ( Zostera spp.) in Chuuk Islands, Micronesia, Central Western Pacific Ocean

    Science.gov (United States)

    Min, Wongi; Kim, Dongsung; Decraemer, Wilfrida; Rho, Hyun Soo

    2016-09-01

    A new species of free-living marine draconematid nematode, Dracograllus trukensis sp. nov., is described based on the specimens collected from the sediments of a intertidal seagrass bed from Chuuk Islands, Micronesia. Dracograllus trukensis sp. nov. differs from other species of the genus by the combination of the following characteristics: the presence of numerous minute spiny ornamented body cuticular annules in both sexes, eight cephalic adhesion tubes inserted on the head capsule in both sexes, the presence of stiff posteriorly directed setae anterior to posterior adhesion tubes in both sexes, the shape (large, elongated, open loop-shaped in male and large, elongated, closed loop-shaped in female) and position (longer ventral arm extending to the first body annule in male) of amphideal fovea, shorter spicule length (34-42 μm), the presence of sexual dimorphism in shape and length of the non-annulated tail terminus, and number of posterior sublateral adhesion tubes (10 in male and 13-15 in female) and posterior subventral adhesion tubes (8-10 in male and 9-11 in female). A comparative table on the biogeographical and ecological characteristics of the species of Dracograllus is presented. This is the first taxonomic report on the genus Dracograllus from Chuuk Islands, Micronesia, central western Pacific Ocean.

  20. The Atlantic Coast of Maryland, Sediment Budget Update: Tier 2, Assateague Island and Ocean City Inlet

    Science.gov (United States)

    2016-06-01

    armoring, and placement of offshore borrow material on the shoreline. Over the past few years, several sediment budgets have been created to identify...sources, sinks, and sediment pathways. The most recent of these budgets covered the 1995 to 2002 and 2004 to 2008 epochs ( Offshore and Coastal...asset/1000361. Offshore and Coastal Technologies, Inc. (OCTI). 2011. Geomorphic and sediment budget analysis of Fenwick and Assateague Islands

  1. Oceanic propagation of a potential tsunami from the La Palma Island

    Science.gov (United States)

    LøVholt, F.; Pedersen, G.; Gisler, G.

    2008-09-01

    The likelihood of a large scale tsunami from the La Palma Island is considered small by most. Nevertheless, the potential catastrophic consequences call for attention. Here we report on numerical simulations of a tsunami that might result from the extreme case of a flank collapse of the Cumbre Vieja volcano at the La Palma Island, done by combining a multimaterial model for the wave generation with Boussinesq models for the far-field propagation. Our simulations show that the slide speed is close to critical, effectively generating an initial wave of several hundred meters height. Our main focus is the wave propagation which is genuinely dispersive. In the far-field, propagation becomes increasingly complex due to the combined effects of dispersion, refraction, and interference in the direction of propagation. Constructive interference of the trailing waves are found to decrease the decay of the maximum amplitude with distance compared to classical asymptotic theory at transatlantic distances. Thus, the commonly used hydrostatic models fail to describe the propagation. Consequences of the La Palma scenario would be largest at the Canary Islands, but our findings also suggests that the whole central Atlantic would face grave consequences. However, the largest surface elevations are smaller than the most pessimistic reports found in literature. We also find undular bores towards the shorelines of America.

  2. Seed dispersal and establishment of endangered plants on Oceanic Islands: the Janzen-Connell model, and the use of ecological analogues.

    Directory of Open Access Journals (Sweden)

    Dennis M Hansen

    Full Text Available BACKGROUND: The Janzen-Connell model states that plant-specific natural enemies may have a disproportionately large negative effect on progeny close to maternal trees. The majority of experimental and theoretical studies addressing the Janzen-Connell model have explored how it can explain existing patterns of species diversity in tropical mainland areas. Very few studies have investigated how the model's predictions apply to isolated oceanic islands, or to the conservation management of endangered plants. Here, we provide the first experimental investigation of the predictions of the Janzen-Connell model on an oceanic island, in a conservation context. In addition, we experimentally evaluate the use of ecological analogue animals to resurrect the functional component of extinct frugivores that could have dispersed seeds away from maternal trees. METHODOLOGY/PRINCIPAL FINDINGS: In Mauritius, we investigated seed germination and seedling survival patterns of the critically endangered endemic plant Syzygium mamillatum (Myrtaceae in relation to proximity to maternal trees. We found strong negative effects of proximity to maternal trees on growth and survival of seedlings. We successfully used giant Aldabran tortoises as ecological analogues for extinct Mauritian frugivores. Effects of gut-passage were negative at the seed germination stage, but seedlings from gut-passed seeds grew taller, had more leaves, and suffered less damage from natural enemies than any of the other seedlings. CONCLUSIONS/SIGNIFICANCE: We provide the first experimental evidence of a distance-dependent Janzen-Connell effect on an oceanic island. Our results potentially have serious implications for the conservation management of rare plant species on oceanic islands, which harbour a disproportionately large fraction of the world's endemic and endangered plants. Furthermore, in contrast to recent controversy about the use of non-indigenous extant megafauna for re

  3. Tropical Wave-Induced Oceanic Eddies at Cabo Corrientes and the Maria Islands, Mexico

    Science.gov (United States)

    2007-05-30

    Hurlburt (1996), Coupled dynamics of the South (2002), Formation of the Haida -1998 oceanic eddy, J. Geophys. Res., China Sea, the Sulu Sea, and the...generation of Haida eddies, Deep Sea Res.. Part 11, 52(7-8), 853-874. Metzger, E. J., H. E. Hurlburt, J. C. Kindle, Z. Sirkes, and J. M. Pringle Enfield, D

  4. Fertility of the Mantle beneath the Ocean Basins: Harzburgite, Lherzolite, and Eclogite in Depleted to Enriched Sources of Abyssal Tholeiites, Ocean Islands, and LIPs

    Science.gov (United States)

    Natland, J. H.; Anderson, D. L.

    2002-12-01

    Current models for the origin of MORB and OIB invoke different degrees of partial melting of a homogeneous lherzolitic source, and a heterogeneous deep mantle source, respectively. In the ocean basins, MORBs are only part of a spectrum of geochemically diverse depleted to enriched basalts that erupt at or near ridges, off-axis seamounts and large igneous provinces. Even at ridges, mantle is locally enriched (e.g. E-MORB). The gradation in compositions from MORB to slightly less depleted tholeiites at LIPS, to variably enriched tholeiitic and alkalic basalts, basanites and olivine nephelinites of many ocean islands requires only differences in depth and degree of partial melting of shallow mantle lherzolite upon which trace-element and isotopic heterogeneity are superimposed. Alkalic basalts and differentiates in the oceans occur along nearly every seamount ridge rising >2000 m above the seafloor, a distribution too extensive to be explained by any number of plumes; this makes a plume origin for similar lavas on linear island chains questionable. Tapping along fractures of a shallow asthenospheric layer of variably enriched and fertile mantle that develops beneath the lithosphere through time is more likely. The long-term differentiation of the Earth, magmatism, recycling, continental rifting, and subduction insure that the upper mantle cannot be well mixed and homogeneous, a common but fallacious assumption in much petrogenetic theory. Mantle major-element and isotopic heterogeneity and variable temperature is a consequence of plate tectonics. Every association of ultramafic rocks in the ocean crust, ophiolites, and xenolith suites demonstrates significant bulk heterogeneity that survives partial melting. Thus sources of modern abyssal tholeiites must be variably fertile with respect to a basaltic melt fraction, and range from average harzburgite to fertile lherzolite, on both local and regional scales. In addition, subduction guarantees that most abyssal basalt

  5. Projected poleward shift of king penguins' (Aptenodytes patagonicus) foraging range at the Crozet Islands, southern Indian Ocean.

    Science.gov (United States)

    Péron, Clara; Weimerskirch, Henri; Bost, Charles-André

    2012-07-07

    Seabird populations of the Southern Ocean have been responding to climate change for the last three decades and demographic models suggest that projected warming will cause dramatic population changes over the next century. Shift in species distribution is likely to be one of the major possible adaptations to changing environmental conditions. Habitat models based on a unique long-term tracking dataset of king penguin (Aptenodytes patagonicus) breeding on the Crozet Islands (southern Indian Ocean) revealed that despite a significant influence of primary productivity and mesoscale activity, sea surface temperature consistently drove penguins' foraging distribution. According to climate models of the Intergovernmental Panel on Climate Change (IPCC), the projected warming of surface waters would lead to a gradual southward shift of the more profitable foraging zones, ranging from 25 km per decade for the B1 IPCC scenario to 40 km per decade for the A1B and A2 scenarios. As a consequence, distances travelled by incubating and brooding birds to reach optimal foraging zones associated with the polar front would double by 2100. Such a shift is far beyond the usual foraging range of king penguins breeding and would negatively affect the Crozet population on the long term, unless penguins develop alternative foraging strategies.

  6. Wide-range genetic connectivity of Coney, Cephalopholis fulva (Epinephelidae, through oceanic islands and continental Brazilian coast

    Directory of Open Access Journals (Sweden)

    Allyson S. de Souza

    2015-03-01

    Full Text Available The Epinephelidae form a group of species of high biological and economical interests. It´s phylogeographic patterns are not well known especially the distributed populations in the western region of the Atlantic Ocean. Among the representatives is a small species called Cephalopholis fulva, Coney, which presents a wide geographical distribution, polychromia, hermaphroditism and is quickly becoming a large target for the exploration of commercial fishing. The genetic and historical demography were obtained through the partial sequence analysis of Control Region from six locations on the coastline of Brazil from the northeast coast to the southwest coast, including the oceanic islands of Rocas Atoll and Fernando de Noronha Archipelago. The analyzed samples revealed a high genetic variability and a strong gene flow among the sampled locations. Additionally, the genetic data revealed that population expansions probably occurred due to the changes in the sea levels that occurred during the Pleistocene. The large population connectivity found in Coney constitutes relevant conditions for their biological conservation.

  7. Transport of nutrients and contaminants from ocean to island by emperor penguins from Amanda Bay, East Antarctic.

    Science.gov (United States)

    Huang, Tao; Sun, Liguang; Wang, Yuhong; Chu, Zhuding; Qin, Xianyan; Yang, Lianjiao

    2014-01-15

    Penguins play important roles in the biogeochemical cycle between Antarctic Ocean and land ecosystems. The roles of emperor penguin Aptenodytes forsteri, however, are usually ignored because emperor penguin breeds in fast sea ice. In this study, we collected two sediment profiles (EPI and PI) from the N island near a large emperor penguin colony at Amanda Bay, East Antarctic and performed stable isotope and element analyses. The organic C/N ratios and carbon and nitrogen isotopes suggested an autochthonous source of organic materials for the sediments of EPI (C/N = 10.21 ± 0.28, n = 17; δ(13)C = -13.48 ± 0.50‰, δ(15)N = 8.35 ± 0.55‰, n = 4) and an allochthonous source of marine-derived organic materials for the sediments of PI (C/N = 6.15 ± 0.08, δ(13)C = -26.85 ± 0.11‰, δ(15)N = 21.21 ± 2.02‰, n = 20). The concentrations of total phosphorus (TP), selenium (Se), mercury (Hg) and zinc (Zn) in PI sediments were much higher than those in EPI, the concentration of copper (Cu) in PI was a little lower, and the concentration of element lead (Pb) showed no difference. As measured by the geoaccumulation indexes, Zn, TP, Hg and Se were from moderately to very strongly enriched in PI, relative to local mother rock, due to the guano input from juvenile emperor penguins. Because of its high trophic level and transfer efficiency, emperor penguin can transport a large amount of nutrients and contaminants from ocean to land even with a relatively small population, and its roles in the biogeochemical cycle between ocean and terrestrial environment should not be ignored. © 2013.

  8. Human Leptospirosis on Reunion Island, Indian Ocean: Are Rodents the (Only Ones to Blame?

    Directory of Open Access Journals (Sweden)

    Vanina Guernier

    2016-06-01

    Full Text Available Although leptospirosis is a zoonosis of major concern on tropical islands, the molecular epidemiology of the disease aiming at linking human cases to specific animal reservoirs has been rarely explored within these peculiar ecosystems.Five species of wild small mammals (n = 995 as well as domestic animals (n = 101 were screened for Leptospira infection on Reunion Island; positive samples were subsequently genotyped and compared to Leptospira from clinical cases diagnosed in 2012-2013 (n = 66, using MLST analysis. We identified two pathogenic species in human cases, namely Leptospira interrogans and Leptospira borgpetersenii. Leptospira interrogans was by far dominant both in clinical samples (96.6% and in infected animal samples (95.8%, with Rattus spp and dogs being its exclusive carriers. The genetic diversity within L. interrogans was apparently limited to two sequence types (STs: ST02, identified among most clinical samples and in all rats with complete MLST, and ST34, identified in six humans, but not in rats. Noteworthy, L. interrogans detected in two stray dogs partially matched with ST02 and ST34. Leptospira borgpetersenii was identified in two clinical samples only (3.4%, as well as in cows and mice; four haplotypes were identified, of which two seemingly identical in clinical and animal samples. Leptospira borgpetersenii haplotypes detected in human cases were clearly distinct from the lineage detected so far in the endemic bat species Mormopterus francoismoutoui, thus excluding a role for this volant mammal in the local human epidemiology of the disease.Our data confirm rats as a major reservoir of Leptospira on Reunion Island, but also pinpoint a possible role of dogs, cows and mice in the local epidemiology of human leptospirosis. This study shows that a comprehensive molecular characterization of pathogenic Leptospira in both clinical and animal samples helps to gaining insight into leptospirosis epidemiology within a specific

  9. Magma storage and migration associated with the 2011-2012 El Hierro eruption: Implications for crustal magmatic systems at oceanic island volcanoes

    Science.gov (United States)

    González, Pablo J.; Samsonov, Sergey V.; Pepe, Susi; Tiampo, Kristy F.; Tizzani, Pietro; Casu, Francesco; Fernández, José; Camacho, Antonio G.; Sansosti, Eugenio

    2013-08-01

    Starting in July 2011, anomalous seismicity was observed at El Hierro Island, a young oceanic island volcano. On 12 October 2011, the process led to the beginning of a submarine NW-SE fissural eruption at ~15 km from the initial earthquake loci, indicative of significant lateral magma migration. Here we conduct a multifrequency, multisensor interferometric analysis of spaceborne radar images acquired using three different satellite systems (RADARSAT-2, ENVISAT, and COSMO-SkyMed (Constellation of Small Satellites for Mediterranean Basin Observation)). The data fully captures both the pre-eruptive and coeruptive phases. Elastic modeling of the ground deformation is employed to constrain the dynamics associated with the magmatic activity. This study represents the first geodetically constrained active magmatic plumbing system model for any of the Canary Islands volcanoes, and one of the few examples of submarine volcanic activity to date. Geodetic results reveal two spatially distinct shallow (crustal) magma reservoirs, a deeper central source (9.5 ± 4.0 km), and a shallower magma reservoir at the flank of the southern rift (4.5 ± 2.0 km). The deeper source was recharged, explaining the relatively long basaltic eruption, contributing to the observed island-wide uplift processes, and validating proposed active magma underplating. The shallowest source may be an incipient reservoir that facilitates fractional crystallization as observed at other Canary Islands. Data from this eruption supports a relationship between the depth of the shallow crustal magmatic systems and the long-term magma supply rate and oceanic lithospheric age. Such a relationship implies that a factor controlling the existence/depth of shallow (crustal) magmatic systems in oceanic island volcanoes is the lithosphere thermomechanical behavior.

  10. Comparison of sand-layer geometry on flat floors of 10 modern depositional basins

    Energy Technology Data Exchange (ETDEWEB)

    Pilkey, O.H. (Duke Univ., Durham, NC); Locker, S.D.; Cleary, W.J.

    1980-06-01

    A comparative study of 10 deep turbidite basins indicates that sand-layer thickness, frequency, and continuity can be related to their basin geometries, tectonics, and source areas. This study is based on piston-core data from the flat floors of four oceanic-crust abyssal plains (Sohm, Hatteras, Blake-Bahama, and Silver), two Bahama-Plateau reentrant basins (Columbus basin and Tongue of the Ocean), three subduction zone-island arc basins (Hispaniola-Caicos, Navidad, and St. Croix basins), and one continental-borderland basin (Santa Monica basin). With increasing tectonic activity, sand layers on flat basin floors tend to be thinner and more frequent. Except in elongated narrow basins such as Navidad, source-area size is directly related to proximal sand-layer thickness. Continuity of individual sand layers is a function of drainage-basin size and depositional-basin shape. For example, on the Hatteras Abyssal Plan long-distance continuity (up to 500 km) of individual sand layers is achieved because most of the turbidites are large and are introduced only at the north upstream end. In the small horseshoe-shaped Columbus basin, sand-layer continuity is limited because flows are small and are introduced from three sides. In most basins, sands thin and the percentage of sand layers in the sediment column decreases away from source areas. However, in basins that are small relative to the typical turbidity-current size (e.g., Hispaniola-Caicos basin), the differences between basin-edge and basin-center sand layers are slight. 10 figures, 3 tables.

  11. Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean

    Directory of Open Access Journals (Sweden)

    C. Venchiarutti

    2011-05-01

    Full Text Available Dissolved and particulate excess 230Th and 231Pa concentrations (noted 230Thxs and 231Paxs, respectively and 231Paxs/230Thxs activity ratios were investigated on and out of the Kerguelen plateau (Southern Ocean in the framework of the KErguelen Ocean and Plateau compared Study project in order to better understand the influence of particle flux and particle chemistry and advection on the scavenging of 231Pa.

    In the wake of Kerguelen Island, the relative abundance of 231Paxs in the particles compared to the dissolved phase associated with a low fractionation factor between 230Th and 231Pa (FTh/Pa ranging from 0.06 ± 0.01 to 2.13 ± 0.63 is consistent with particles being dominated by biogenic silica in this area. Strong 231Pa concentration gradients occur on relatively short distances.

    Along the eastern escarpment of the Kerguelen plateau, an intensive scavenging affects significantly the dissolved distribution of 231Paxs at depth, as already observed for 230Thxs. This local boundary scavenging was attributed to re-suspension of opal-rich particles by nepheloid layers, resulting in fractionation factors FTh/Pa ≤ 1 along the Kerguelen plateau slope. Therefore, these results showed that in the Kerguelen wake, both the composition (biogenic opal and the flux (intensive along the margin of particles control the scavenging of the two radionuclides.

    The modelling of 231Pa distribution with an advection-scavenging model demonstrate that lateral advection of open ocean water on the Kerguelen plateau could supply most of the 231Pa, which is then efficiently scavenged on the highly productive plateau, as previously proposed for 230

  12. Detrital chrome spinel evidence for a Neotethyan intra-oceanic island arc collision with India in the Paleocene

    Science.gov (United States)

    Baxter, Alan T.; Aitchison, Jonathan C.; Ali, Jason R.; Chan, Jacky Sik-Lap; Chan, Gavin Heung Ngai

    2016-10-01

    Models that support a single collision scenario for India and Eurasia are incompatible with the evidence that an intra-oceanic island arc (IOIA) existed within the Neotethyan Ocean. Understanding the spatial and temporal extent of any IOIA is crucial for India-Eurasia collision studies as the entire ocean, including any intra-oceanic features, must have been consumed or emplaced prior to continental collision. Here, we review what is known about the Neotethyan IOIA and report evidence from sedimentary successions in NW India and southern Tibet to constrain when and where it was emplaced. We use detrital mineral geochemistry and supporting provenance and age data to identify the source of the sediments and compare the timing of erosion of IOIA-derived material in both regions. Detrital chrome spinels, extracted from distinct sedimentary horizons in southern Tibet (Sangdanlin) and NW India (Ladakh), exhibit similar average geochemical values (TiO2 = 0.09 and 0.24%, Cr# = 0.66 and 0.68 and Mg# = 0.45 and 0.53, respectively) and supra-subduction zone (SSZ), forearc peridotite signatures. Furthermore, they overlap with in-situ chrome spinels reported from the Spongtang Ophiolite in NW India and the Sangsang Ophiolite in southern Tibet. As with many of the ophiolitic remnants that crop out in and adjacent to the Yarlung-Tsangpo and Indus suture zones (YTSZ and ISZ respectively), the Spongtang and Sangsang ophiolites formed in an IOIA setting. Linking the source of the detrital chrome spinels to those analysed from remnant IOIA massifs in the YTSZ and ISZ is strong evidence for the emplacement of the IOIA onto the Indian margin. The timing of the IOIA collision with India is constrained by the depositional ages of the chrome spinel-bearing sediments to the end of the Paleocene (Thanetian) in southern Tibet and the Early Eocene in NW India. This indirectly provides a maximum age constraint of Late Paleocene-Early Eocene for intercontinental collision between India and

  13. Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean)

    CERN Document Server

    Carvallo, C; Ruffet, G; Henry, B I; Poidras, T; Carvallo, Claire; Camps, Pierre; Ruffet, Gilles; Henry, Bernard; Proxy, Thierry Poidras

    2003-01-01

    We report a survey carried out on basalt flows from Amsterdam Island in order to check the presence of intermediate directions interpreted to belong to a geomagnetic field excursion within the Brunhes epoch, completing this paleomagnetic record with paleointensity determinations and radiometric dating. The directional results corroborate the findings by Watkins and Nougier (1973) : normal polarity is found for two units and an intermediate direction, with associated VGPs close to the equator, for the other two units. A notable result is that these volcanic rocks are well suited for absolute paleointensity determinations. Fifty percent of the samples yields reliable intensity values with high quality factors. An original element of this study is that we made use of the PTRM-tail test of Shcherbakova et al. (2000) to help in the interpretation of the paleointensity measurements. Doing thus, only the high temperature intervals, beyond 400 degres C, were retained to obtain the most reliable estimate of the streng...

  14. Reproductive pattern of Pterocladiella capillacea (Gelidiales, Rhodophyta) at Canary Islands (Spain, Atlantic Ocean)

    Institute of Scientific and Technical Information of China (English)

    Mascha Stroobant; Milena Polifrone

    2014-01-01

    Objective: To record the reproductive pattern of a natural population of Pterocladiella capillacea from Gáldar (Canary Islands, Spain) from February to August in relation to temperature, irradiance and photoperiod environmental conditions.Methods:Field observation of reproductive thalli was used at different seasons in the year. Results: Tetrasporophytes and vegetative thalli were observed during all the period of study, while female gametophytes bearing cystocarps have been found from May to August in correspondence with the highest water temperature and irradiance values.Conclusions:Our data suggest that the temperature may be the determining factor which regulates the presence of tetrasporophytes in the field. The constant presence of tetrasporophytes could depend on the low excursion range of water temperature (4-5 °C) throughout the period of study, with the highest abundance in February at 20 °C.

  15. Seasonality of human leptospirosis in Reunion Island (Indian Ocean and its association with meteorological data.

    Directory of Open Access Journals (Sweden)

    Amélie Desvars

    Full Text Available BACKGROUND: Leptospirosis is a disease which occurs worldwide but particularly affects tropical areas. Transmission of the disease is dependent on its excretion by reservoir animals and the presence of moist environment which allows the survival of the bacteria. METHODS AND FINDINGS: A retrospective study was undertaken to describe seasonal patterns of human leptospirosis cases reported by the Centre National de Références des Leptospiroses (CNRL, Pasteur Institute, Paris between 1998 and 2008, to determine if there was an association between the occurrence of diagnosed cases and rainfall, temperature and global solar radiation (GSR. Meteorological data were recorded in the town of Saint-Benoît (Météo France "Beaufonds-Miria" station, located on the windward (East coast. Time-series analysis was used to identify the variables that best described and predicted the occurrence of cases of leptospirosis on the island. Six hundred and thirteen cases were reported during the 11-year study period, and 359 cases (58.56% were diagnosed between February and May. A significant correlation was identified between the number of cases in a given month and the associated cumulated rainfall as well as the mean monthly temperature recorded 2 months prior to diagnosis (r = 0.28 and r = 0.23 respectively. The predictive model includes the number of cases of leptospirosis recorded 1 month prior to diagnosis (b = 0.193, the cumulated monthly rainfall recorded 2 months prior to diagnosis (b = 0.145, the average monthly temperature recorded 0 month prior to diagnosis (b = 3.836, and the average monthly GSR recorded 0 month prior to diagnosis (b = -1.293. CONCLUSIONS: Leptospirosis has a seasonal distribution in Reunion Island. Meteorological data can be used to predict the occurrence of the disease and our statistical model can help to implement seasonal prevention measures.

  16. Lead isotope signatures of Kerguelen plume-derived olivine-hosted melt inclusions: Constraints on the ocean island basalt petrogenesis

    Science.gov (United States)

    Borisova, Anastassia Y.; Faure, François; Deloule, Etienne; Grégoire, Michel; Béjina, Frédéric; de Parseval, Philippe; Devidal, Jean-Luc

    2014-06-01

    The nature of magmatic sources reflected by isotopic composition of the ocean island basalt (OIB) remains an on-going question in igneous geochemistry. To constrain the magmatic sources for OIB related to the Kerguelen plume activity, we performed detailed microanalytical investigation of the 21.4 Ma picritic basalt (MD109-D6-87) dredged during the “Marion Dufresne” cruise on a seamount between Kerguelen Archipelago and Heard Island. Lead isotope compositions of olivine-hosted melt inclusions and matrix glasses were measured by Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS). We also performed major and trace element microanalyses and mapping of the inclusions and the host olivine phenocrysts by electron microprobe (wavelength-dispersive X-ray spectroscopy, WDS). The observed significant major element (K2O/P2O5, Al2O3/TiO2) and Pb isotope (207Pb/206Pb and 208Pb/206Pb) heterogeneities of parental melts (MgO = 7-10 wt.%) during early high pressure crystallisation stage (200-300 MPa, Fo82-86 mol%), and relative homogeneity at later lower-pressure crystallisation stage ( 4), Al2O3/TiO2 (> 4) ratios are attributed to assimilation of the plateau basaltic crust (≥ 50 wt.%) by the melts in the magma chamber at palaeodepths from 6 to 9 km. The crustal assimilation may have happened through plagioclase dissolution. The large chemical and isotopic heterogeneity of the parental OIB melts found by in situ microanalyses in this study suggests that the bulk rock chemistry alone cannot provide enough information to constrain the nature of the magmatic sources.

  17. Use of habitats as surrogates of biodiversity for efficient coral reef conservation planning in Pacific Ocean islands.

    Science.gov (United States)

    Dalleau, Mayeul; Andréfouët, Serge; Wabnitz, Colette C C; Payri, Claude; Wantiez, Laurent; Pichon, Michel; Friedman, Kim; Vigliola, Laurent; Benzoni, Francesca

    2010-04-01

    Marine protected areas (MPAs) have been highlighted as a means toward effective conservation of coral reefs. New strategies are required to more effectively select MPA locations and increase the pace of their implementation. Many criteria exist to design MPA networks, but generally, it is recommended that networks conserve a diversity of species selected for, among other attributes, their representativeness, rarity, or endemicity. Because knowledge of species' spatial distribution remains scarce, efficient surrogates are urgently needed. We used five different levels of habitat maps and six spatial scales of analysis to identify under which circumstances habitat data used to design MPA networks for Wallis Island provided better representation of species than random choice alone. Protected-area site selections were derived from a rarity-complementarity algorithm. Habitat surrogacy was tested for commercial fish species, all fish species, commercially harvested invertebrates, corals, and algae species. Efficiency of habitat surrogacy varied by species group, type of habitat map, and spatial scale of analysis. Maps with the highest habitat thematic complexity provided better surrogates than simpler maps and were more robust to changes in spatial scales. Surrogates were most efficient for commercial fishes, corals, and algae but not for commercial invertebrates. Conversely, other measurements of species-habitat associations, such as richness congruence and composition similarities provided weak results. We provide, in part, a habitat-mapping methodology for designation of MPAs for Pacific Ocean islands that are characterized by habitat zonations similar to Wallis. Given the increasing availability and affordability of space-borne imagery to map habitats, our approach could appreciably facilitate and improve current approaches to coral reef conservation and enhance MPA implementation.

  18. Reproductive phenology of three species of Gelidiales (Rhodophyta in two macroalgal communities from Tenerife (Atlantic Ocean, Canary Islands, Spain

    Directory of Open Access Journals (Sweden)

    Polifrone, Milena

    2012-12-01

    Full Text Available The reproductive phenology of three species of Gelidiales, Gelidium canariense, Gelidium arbuscula and Pterocladiella capillacea, was analysed seasonally for a period of one year in two localities on the West coast of Tenerife (Atlantic Ocean, Canary Islands, Spain. Considerations are provided on sex ratio, maximum length and branch order of uprights and on the length of the thalli for each sexual and asexual phase of the Canary Islands populations. The three species were characterized by a high percentage of tetrasporophytes, while female and male gametophytes have been observed only in little proportion. Only G. canariense showed gametophytes in all seasons while the occurrence of gametophytes in G. arbuscula and Pterocladiella capillacea demonstrated a clear seasonality.

    La fenología reproductiva de tres especies de Gelidiales, Gelidium canariense, Gelidium arbuscula y Pterocladiella capillacea, ha sido analizada estacionalmente por un periodo de un año en dos localidades de la costa este de Tenerife (Oceano Atlántico, Islas Canarias, España. Se realizan consideraciones sobre sex ratio, longitud máxima y orden de ramificación de los ramets y se aporta información sobre la longitud del talo por cada fase sexual y asexual de las poblaciones canarias. Las tres especies se caracterizan por presentar un elevado porcentaje de tetrasporofitos, mientras que los gametofitos masculinos y femeninos han sido observados en proporciones reducidas. Sólo G. canariense presenta gametofitos en todas las estaciones, mientras que en G. arbuscula y Pterocladiella capillacea demostraban una clara estacionalidad.

  19. Deformation in a hyperslow oceanic rift: Insights from the tectonics of the São Miguel Island (Terceira Rift, Azores)

    Science.gov (United States)

    Sibrant, A. L. R.; Marques, F. O.; Hildenbrand, A.; Boulesteix, T.; Costa, A. C. G.; Catalão, J.

    2016-02-01

    The evolution of hyperslow oceanic rifts, like the Terceira Rift (TR) in the Azores, is still poorly understood. Here we examine the distribution of strain and magmatism in the portion of the TR making up the Nubia-Eurasia plate boundary. We use São Miguel Island because it stretches most of the TR width, which allows to investigate the TR's architecture and shedding light on TR's age and mode of deformation. From topography and structural analysis, and new measurements of 380 faults and dikes, we show that (1) São Miguel has two main structural directions, N150 and N110, mostly concentrated in the eastern part of the island as an onshore continuation of the faults observed offshore in the NE (N110 faults) and SW (N140) TR walls; (2) a new N50-N80 fault system is identified in São Miguel; (3) fault and dike geometries indicate that eastern São Miguel comprises the TR's northern boundary, and the lack of major faults in central and western São Miguel indicates that rifting is mostly concentrated at master faults bounding the TR. Based on TR's geometry, structural observations and plate kinematics, we estimate that the TR initiated between 1.4 and 2.7 Ma ago and that there is no appreciable seafloor spreading associated with rifting. Based on plate kinematics, on the new structural data, and on São Miguel's structural and volcanic trends, we propose that the eastern two thirds of São Miguel lie along a main TR-related transform fault striking N70-N80, which connects two widely separated N130-N150 TR-trending segments.

  20. Key role of organic complexation of iron in sustaining phytoplankton blooms in the Pine Island and Amundsen Polynyas (Southern Ocean)

    Science.gov (United States)

    Thuróczy, Charles-Edouard; Alderkamp, Anne-Carlijn; Laan, Patrick; Gerringa, Loes J. A.; Mills, Matthew M.; Van Dijken, Gert L.; De Baar, Hein J. W.; Arrigo, Kevin R.

    2012-09-01

    Primary productivity in the Amundsen Sea (Southern Ocean) is among the highest in Antarctica. The summer phytoplankton bloom in 2009 lasted for >70 days in both the Pine Island and Amundsen Polynyas. Such productive blooms require a large supply of nutrients, including the trace metal iron (Fe). The organic complexation of dissolved Fe was investigated in the Amundsen Sea during the spring of 2009 to better understand the potential role of ligands in enhancing the local stock of dissolved Fe. The main sources of Fe and ligands to the Amundsen Sea are thought to be melting sea-ice and the Circumpolar Deep Water (CDW), which is modified (MCDW) on the continental shelf and upwells beneath the coastal glaciers and ice-shelves. Upwelling of relatively warm MCDW is also responsible for the rapid melting of the Pine Island Glacier (PIG) and surrounding ice-shelves, resulting in additional release of Fe into surface waters. At upwelling stations near ice shelves, organic ligands were nearly saturated with Fe, thus enhancing the stock of Fe and its availability to the phytoplankton community. However, ligands had little capacity to buffer additional Fe input from glacial melt. In these coastal upwelling regions, much of the glacial Fe supply is lost due to vertical export of Fe via scavenging and precipitation. Conversely, within the phytoplankton bloom in the nearby coastal polynyas, the uptake of Fe combined with the production of organic matter enhanced the abundance of relatively unsaturated organic ligands capable of stabilizing additional Fe supplied from glacial melt. These unsaturated dissolved organic ligands, combined with the continuous input of Fe (dissolved and particulate) from glacial melt, appear to favor the solubilization of Fe, thus increasing the stock of bioavailable Fe and fueling the phytoplankton bloom.

  1. Biological productivity regime and associated N cycling in the vicinity of Kerguelen Island area, Southern Ocean

    Science.gov (United States)

    Cavagna, A. J.; Fripiat, F.; Elskens, M.; Dehairs, F.; Mangion, P.; Chirurgien, L.; Closset, I.; Lasbleiz, M.; Flores-Leiva, L.; Cardinal, D.; Leblanc, K.; Fernandez, C.; Lefèvre, D.; Oriol, L.; Blain, S.; Quéguiner, B.

    2014-12-01

    Although the Southern Ocean is considered a High Nutrient Low Chlorophyll area (HNLC), massive and recurrent blooms are observed over and downstream the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N-uptake (NO3- and NH4+), and nitrification rates were measured at 8 stations in austral spring 2011 (October-November) during the KEOPS2 cruise in the Kerguelen area. Iron fertilization stimulates primary production, with integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m-2 d-1 and up to 0.31 d-1, respectively) compared to the HNLC reference site (12 mmol C m-2 d-1 and 0.06 d-1, respectively). Primary production is mainly sustained by nitrate uptake, with f ratio (corresponding to NO3- uptake/(NO3- uptake + NH4+ uptake)) lying in the upper end of the observations for the Southern Ocean (up to 0.9). Unexpectedly, we report unprecedented rates of nitrification (up to ~3 mmol C m-2 d-1, with ~90% of them organic matter, and (iii) an efficient food web, allowing the reprocessing of organic N and the retention of nitrogen into the dissolved phase through ammonium, the substrate for nitrification.

  2. Migrant biomass and respiratory carbon flux by zooplankton and micronekton in the subtropical northeast Atlantic Ocean (Canary Islands)

    Science.gov (United States)

    Ariza, A.; Garijo, J. C.; Landeira, J. M.; Bordes, F.; Hernández-León, S.

    2015-05-01

    Diel Vertical Migration (DVM) in marine ecosystems is performed by zooplankton and micronekton, promoting a poorly accounted export of carbon to the deep ocean. Major efforts have been made to estimate carbon export due to gravitational flux and to a lesser extent, to migrant zooplankton. However, migratory flux by micronekton has been largely neglected in this context, due to its time-consuming and difficult sampling. In this paper, we evaluated gravitational and migratory flux due to the respiration of zooplankton and micronekton in the northeast subtropical Atlantic Ocean (Canary Islands). Migratory flux was addressed by calculating the biomass of migrating components and measuring the electron transfer system (ETS) activity in zooplankton and dominant species representing micronekton (Euphausia gibboides, Sergia splendens and Lobianchia dofleini). Our results showed similar biomass in both components. The main taxa contributing to DVM within zooplankton were juvenile euphausiids, whereas micronekton were mainly dominated by fish, followed by adult euphausiids and decapods. The contribution to respiratory flux of zooplankton (3.4 ± 1.9 mg C m-2 d-1) was similar to that of micronekton (2.9 ± 1.0 mg C m-2 d-1). In summary, respiratory flux accounted for 53% (range 23-71) of the gravitational flux measured at 150 m depth (11.9 ± 5.8 mg C m-2 d-1). However, based on larger migratory ranges and gut clearance rates, micronekton are expected to be the dominant component that contributes to carbon export in deeper waters. Micronekton estimates in this paper as well as those in existing literature, although variable due to regional differences and difficulties in calculating their biomass, suggest that carbon fluxes driven by this community are important for future models of the biological carbon pump.

  3. Causes of seasonal and decadal variability in a tropical seagrass seascape (Reunion Island, south western Indian Ocean)

    Science.gov (United States)

    Cuvillier, A.; Villeneuve, N.; Cordier, E.; Kolasinski, J.; Maurel, L.; Farnier, N.; Frouin, P.

    2017-01-01

    While seagrass meadows are considered as vulnerable or declining habitats worldwide, facing many natural and anthropogenic pressures, the opposite trend is suggested by this study in Reunion Island (Indian Ocean). Located at the benthos-pelagos interface, seagrass beds are critical coastal habitats and can be used as relevant health indicators for larger marine ecosystems or land-sea continuum. In order to determine which are the factors driving seagrass ecosystems health it is essential to quantify their seascape pattern fluctuations. The long-term (over 65 years) and seasonal scale variability was assessed in the monospecific Syringodium isoetifolium seagrass bed seascape at the Ermitage/La Saline fringing reef using aerial photographs and field measurements. Both long-term and short-term scales have been informative and both types of monitoring appear as useful tools for seagrass ecosystem management. Strong variations in seagrass coverage were observed in the 16 rasters analyzed from years 1950-2015, the magnitude order was however similar to the one observed at the recent seasonal scale (up to 2016 m2 gained or 4863 m2 lost over few months at site scale). Seascape pattern analysis revealed that physical factors (swell events, cyclones) had a major impact on the ocean-exposed site with varying impact degree depending on frequency, duration and intensity. Biotic (herbivory) or anthropogenic (grubbing, nutrient inputs) factors were also identified to influence the structural shape, fragmentation, or disappearance of seagrass beds. Further work is required to better quantify the effect of each single factor, a difficult task due to their combined expression. At the reef scale, these results showed a positive correlation between seagrass beds and inner reef flat coverage suggesting that common factors drive these highly resilient ecosystems.

  4. Relationship between species diversity and reef growth in the Holocene at Ishigaki Island, Pacific Ocean

    Science.gov (United States)

    Hongo, Chuki; Kayanne, Hajime

    2010-01-01

    Coral reefs are influenced by global and local factors, and living corals are currently faced with a potential loss of species diversity. Knowledge of the relationship between species diversity and reef growth during the Holocene is important in terms of accurately reconstructing natural conditions prior to recent disturbances (e.g., human impact, pollution, and over-harvesting) and in predicting future scenarios (e.g., abrupt sea-level rise, coastal change, and economic services). This study seeks to characterize the Holocene and present-day reef at Ishigaki Island in the Ryukyu Islands, focusing on spatial and temporal variations in the relationship between species diversity and reef growth. The analysis is based on a drilling core obtained for the Holocene reefs and quantitative species-diversity data (Shannon and Weaver's diversity index, H') obtained for the present-day reef. H' was calculated for four coral communities surveyed at the Ibaruma and Fukido reefs. The Holocene sequence was dominated by the corymbose coral community (e.g., Acropora digitifera, A. hyacinthus, Goniastrea retiformis, and Platygyra ryukyuensis), yielding an H' value of 1.6. The encrusting coral community (e.g., Echinopora lamellose and Pachyseris rugosa) showed the highest diversity at the reef ( H' = 2.2); however, this community was not one of the main reef builders during the Holocene. The massive coral community (e.g., Porites lutea and Favites chinensis) showed the lowest diversity ( H' = 0.6). It also made a minor contribution to reef building; this community appeared in a shallow lagoon once sea level had stabilized. The arborescent coral community (e.g., A. formosa and A. nobilis) was one of the main reef builders, although yielding an H' value of much less than 1.0. Species diversity is not a prerequisite in terms of Holocene reef growth. Thus, a few species (e.g., A. digitifera, A. hyacinthus, A. formosa, A. nobilis, G. retiformis, and P. ryukyuensis) from two main reef

  5. Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

    Science.gov (United States)

    Cavagna, A. J.; Fripiat, F.; Elskens, M.; Mangion, P.; Chirurgien, L.; Closset, I.; Lasbleiz, M.; Florez-Leiva, L.; Cardinal, D.; Leblanc, K.; Fernandez, C.; Lefèvre, D.; Oriol, L.; Blain, S.; Quéguiner, B.; Dehairs, F.

    2015-11-01

    Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO3- and NH4+), and nitrification rates were measured at eight stations in austral spring 2011 (October-November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m-2 d-1 and up to 0.31 d-1 respectively) compared to the HNLC reference site (12 mmol C m-2 d-1 and 0.06 d-1 respectively). Primary production was mainly sustained by nitrate uptake, with f ratios (corresponding to NO3--uptake / (NO3--uptake + NH4+-uptake)) lying at the upper end of the observations for the Southern Ocean (up to 0.9). We report high rates of nitrification (up to ~ 3 μmol N L-1 d-1, with ~ 90 % of them efficiently compete with phytoplankton for the ammonium produced by remineralization at low-light intensities. Nitrate produced by nitrification in the mixed layer below the euphotic zone is easily supplied to the euphotic zone waters above, and nitrification sustained 70 ± 30 % of the nitrate uptake in the productive area above the Kerguelen Plateau. This complicates estimations of new production as potentially exportable production. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.

  6. Drift, not selection, shapes toll-like receptor variation among oceanic island populations.

    Science.gov (United States)

    Gonzalez-Quevedo, Catalina; Spurgin, Lewis G; Illera, Juan Carlos; Richardson, David S

    2015-12-01

    Understanding the relative role of different evolutionary forces in shaping the level and distribution of functional genetic diversity among natural populations is a key issue in evolutionary and conservation biology. To do so accurately genetic data must be analysed in conjunction with an unambiguous understanding of the historical processes that have acted upon the populations. Here, we focused on diversity at toll-like receptor (TLR) loci, which play a key role in the vertebrate innate immune system and, therefore, are expected to be under pathogen-mediated selection. We assessed TLR variation within and among 13 island populations (grouped into three archipelagos) of Berthelot's pipit, Anthus berthelotii, for which detailed population history has previously been ascertained. We also compared the variation observed with that found in its widespread sister species, the tawny pipit, Anthus campestris. We found strong evidence for positive selection at specific codons in TLR1LA, TLR3 and TLR4. Despite this, we found that at the allele frequency level, demographic history has played the major role in shaping patterns of TLR variation in Berthelot's pipit. Levels of diversity and differentiation within and across archipelagos at all TLR loci corresponded very closely with neutral microsatellite variation and with the severity of the bottlenecks that occurred during colonization. Our study shows that despite the importance of TLRs in combating pathogens, demography can be the main driver of immune gene variation within and across populations, resulting in patterns of functional variation that can persist over evolutionary timescales.

  7. Patterns of introduction and diversification of Vanilla planifolia (Orchidaceae) in Reunion Island (Indian Ocean).

    Science.gov (United States)

    Bory, Severine; Lubinsky, Pesach; Risterucci, Ange-Marie; Noyer, Jean-Louis; Grisoni, Michel; Duval, Marie-France; Besse, Pascale

    2008-07-01

    The cultivated species Vanilla planifolia is a typical example of a crop introduced from its area of origin (America) to new regions where natural pollinators are absent. Although the Vanilla cultivars are exclusively vegetatively propagated, a high degree of phenotypic variation is observed among the cultivars in their introduction areas such as Reunion Island. To test several hypotheses explaining this variation-different introduction events, somatic mutations and sexual reproduction (through manual pollination)-we used AFLP markers to elucidate the patterns of introduction of V. planifolia. Most of the accessions cultivated in the world were derived from a single accession, possibly the Mexican cultivar Mansa. The patterns of diversification of this cultivated species were also studied and compared with other cultivated (V. tahitensis) and wild (V. pompona and V. bahiana) species. Except for one particular phenotype ('Aiguille'), which may come from sexual reproduction, cultivated accessions exhibit very low levels of genetic diversity. They have evolved by the accumulation of point mutations through vegetative multiplication. The genetic diversity revealed could not explain the phenotypic diversity, which may be related to epigenetics or polyploidy. This new understanding of the basis of genetic diversity of vanilla may assist to improve management of genetic resources.

  8. Juvenile songbirds compensate for displacement to oceanic islands during autumn migration.

    Directory of Open Access Journals (Sweden)

    Kasper Thorup

    Full Text Available To what degree juvenile migrant birds are able to correct for orientation errors or wind drift is still largely unknown. We studied the orientation of passerines on the Faroe Islands far off the normal migration routes of European migrants. The ability to compensate for displacement was tested in naturally occurring vagrants presumably displaced by wind and in birds experimentally displaced 1100 km from Denmark to the Faroes. The orientation was studied in orientation cages as well as in the free-flying birds after release by tracking departures using small radio transmitters. Both the naturally displaced and the experimentally displaced birds oriented in more easterly directions on the Faroes than was observed in Denmark prior to displacement. This pattern was even more pronounced in departure directions, perhaps because of wind influence. The clear directional compensation found even in experimentally displaced birds indicates that first-year birds can also possess the ability to correct for displacement in some circumstances, possibly involving either some primitive form of true navigation, or 'sign posts', but the cues used for this are highly speculative. We also found some indications of differences between species in the reaction to displacement. Such differences might be involved in the diversity of results reported in displacement studies so far.

  9. Seismic signature of a phreatic explosion: Hydrofracturing damage at Karthala volcano, Grande Comore Island, Indian Ocean

    Science.gov (United States)

    Savin, C.; Grasso, J.-R.; Bachelery, P.

    2005-01-01

    Karthala volcano is a basaltic shield volcano with an active hydrothermal system that forms the southern two-thirds of the Grande Comore Island, off the east coat of Africa, northwest of Madagascar. Since the start of volcano monitoring by the local volcano observatory in 1988, the July 11th, 1991 phreatic eruption was the first volcanic event seismically recorded on this volcano, and a rare example of a monitored basaltic shield. From 1991 to 1995 the VT locations, 0.5activation of the whole hydrothermal system, as roughly sized by the distribution of VT hypocenters. The seismicity rate in 1995 was still higher than the pre-eruption seismicity rate, and disagrees with the time pattern of thermo-elastic stress readjustment induced by single magma intrusions at basaltic volcanoes. We propose that it corresponds to the still ongoing relaxation of pressure heterogeneity within the hydrothermal system as suggested by the few LP events that still occurred in 1995. ?? Springer-Verlag 2005.

  10. Digital Video taken during the 3-person submersible Clelia dive 608 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, August 30, 2001 (NCEI Accession 0039353)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Islands in the Stream is a three-month scientific expedition to marine protected areas and other habitats being considered for protection from offshore of Belize in...

  11. Digital Video taken during the 3-person submersible Clelia dive 607 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, August 29, 2001 (NCEI Accession 0039467)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Islands in the Stream is a three-month scientific expedition to marine protected areas and other habitats being considered for protection from offshore of Belize in...

  12. Turbidity, SOLAR RADIATION - ATMOSPHERIC and other data from USCGC BURTON ISLAND, USCGC GLACIER and USCGC NORTHWIND in the Arctic Ocean from 1971-07-30 to 1977-08-05 (NCEI Accession 7800474)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salinity, temperature, depth (STD) and other data was collected using the United States Coast Guard (USCG) ships BURTON ISLAND, GLACIER and NORTH WIND by the US...

  13. Oceanographic Data collected during the Islands in the Stream Expedition on NOAA Ship Gordon Gunter in the North Atlantic Ocean and the Gulf of Mexico between 2001-05-10 to 2001-10-04 (NCEI Accession 0104416)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Islands in the Stream expedition explored protected and unprotected deep water coral reefs and hard-bottom communities throughout the Gulf of Mexico and South...

  14. Study of Groundwater Circulation Using Stable Isotopes : the Example of the Punaruu Watershed (Tropical Oceanic Island of Tahiti, French Polynesia)

    Science.gov (United States)

    Sichoix, L.; Hildenbrand, A.; Marlin, C.; Gillot, P. Y.; Pheulpin, L.; Barriot, J. P.

    2015-12-01

    The increasing demand for drinking and industrial water, especially in the most populated areas of the tropical oceanic Island of Tahiti in French Polynesia (South central Pacific), makes it necessary to conduct hydrological and hydrogeological studies on water resources and management. Our investigation area represents the second largest watershed of Tahiti called Punaruu. The largest industrial zone of Tahiti occupies the minor low valley of this catchment and is particularly impacted by dredging of the stream and rock removals since several decades whereas the major high part is naturally well preserved. This study aims to identify the main infiltration areas of the aquifers of this industrial zone as well as the areas at low elevations to be protected from potential pollutions. During the period between May 2013 and July 2015, we have collected rainwater samples from five rain gauges located at elevations ranging from 0 to 1420 m. We have also performed water sampling from the main rivers and three springs up to altitudes of 800 m as well as six pumping boreholes in the industrial zone. Chemical (major elements) and stable isotopic (δ18O and δ2H) analyses have been done from all these water samples and help us to constrain a conceptual model of groundwater circulation within such a complex discontinuous volcanic structure.

  15. Diadema ascensionisMortensen, 1909 (Echinodermata: Echinoidea is not restricted to Oceanic Islands: evidence from morphological data

    Directory of Open Access Journals (Sweden)

    AI Gondim

    Full Text Available The genus Diadema presently consists of seven species, two of which are known from the Brazilian coast: D. antillarum and D. ascensionis. The first is usually known for shallow coastal areas, while the second was apparently restricted to oceanic islands. In February 2011, a dense population of D. ascensionis was observed on the coastal reefs of Praia do Francês (Alagoas State, northeastern Brazil. Five specimens were collected and transported to the laboratory where morphological studies of the test and pedicellariae were conducted. Subsequently, visits were made to scientific collections in order to compare and confirm species identifications. Our observations confirm the presence of tridentate pedicellariae with narrow and strongly curved valves. The axial cavity in the tips of the spines is filled with dense nonreticular tissue. This taxonomic data confirms the occurrence of D. ascensionis in coastal areas. On the coastal reefs of Praia do Francês, animals were observed from the beach to the reef formations about 200 m offshore in areas with a sandy substrate and in reef cavities, usually in clear and well illuminated waters. Solitary individuals or groups of up to 15 individuals formed dense populations in the area. We stress the importance of pedicellariae for the specific identification of the Diadematidae, considering that they are quite constant and reliable at this taxonomic level. Our results demonstrate that D. ascensionis is not restricted to insular environments and that this species may be common in shallow coastal habitats.

  16. Simulation of Ship-Track versus Satellite-Sensor Differences in Oceanic Precipitation Using an Island-Based Radar

    Directory of Open Access Journals (Sweden)

    Jörg Burdanowitz

    2017-06-01

    Full Text Available The point-to-area problem strongly complicates the validation of satellite-based precipitation estimates, using surface-based point measurements. We simulate the limited spatial representation of light-to-moderate oceanic precipitation rates along ship tracks with respect to areal passive microwave satellite estimates using data from a subtropical island-based radar. The radar data serves to estimate the discrepancy between point-like and areal precipitation measurements. From the spatial discrepancy, two statistical adjustments are derived so that along-track precipitation ship data better represent areal precipitation estimates from satellite sensors. The first statistical adjustment uses the average duration of a precipitation event as seen along a ship track, and the second adjustment uses the median-normalized along-track precipitation rate. Both statistical adjustments combined reduce the root mean squared error by 0.24 mm h − 1 (55% compared to the unadjusted average track of 60 radar pixels in length corresponding to a typical ship speed of 24–34 km h − 1 depending on track orientation. Beyond along-track averaging, the statistical adjustments represent an important step towards a more accurate validation of precipitation derived from passive microwave satellite sensors using point-like along-track surface precipitation reference data.

  17. PRELIMINARY ANALYSIS OF THE EARTHQUAKE (MW 8.1 AND TSUNAMI OF APRIL 1, 2007, IN THE SOLOMON ISLANDS, SOUTHWESTERN PACIFIC OCEAN

    Directory of Open Access Journals (Sweden)

    Michael A. Fisher

    2007-01-01

    Full Text Available On April 1, 2007, a destructive earthquake (Mw 8.1 and tsunami struck the central Solomon Islands arc in the southwestern Pacific Ocean. The earthquake had a thrust-fault focal mechanism and occurred at shallow depth (between 15 km and 25 km beneath the island arc. The combined effects of the earthquake and tsunami caused dozens of fatalities and thousands remain without shelter. We present a preliminary analysis of the Mw-8.1 earthquake and resulting tsunami. Multichannel seismic- reflection data collected during 1984 show the geologic structure of the arc’s frontal prism within the earthquake’s rupture zone. Modeling tsunami-wave propagation indicates that some of the islands are so close to the earthquake epicenter that they were hard hit by tsunami waves as soon as 5 min. after shaking began, allowing people scant time to react.

  18. AFSC/RACE/SAP/Foy: Effects of ocean acidification on embryo stages of Tanner crab: Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the embryo stages of the economically important southern Tanner crab,...

  19. Metals in Mullus surmuletus and Pseudupeneus prayensis from the Canary Islands (Atlantic Ocean).

    Science.gov (United States)

    Dorta, Paola; Rubio, Carmen; Lozano, Gonzalo; González-Weller, Dailos; Gutiérrez, Ángel; Hardisson, Arturo; Revert, Consuelo

    2015-12-01

    A total of 20 metals (Na, K, Ca, Mg, B, Ba, Co, Cr, Cu, Sr, Fe, Li, Mn, Mo, Ni, V, Zn, Al, Cd, and Pb) were analyzed by inductively coupled plasma optical emission spectrometry in muscle and liver tissue from a total of 28 examples of the fishes Mullus surmuletus and Pseudupeneus prayensis marketed in Tenerife, Canary Islands (Spain). Significant differences (P < 0.05) in B, K, Mg, Mn, and Na concentrations were found between muscle and liver. The mean concentrations of K (1,388.04 mg/kg wet weight [wet wt]) and Mg (153.33 mg/kg wet wt) were higher in muscle than in liver (697.49 and 114.21 mg/kg wet wt, respectively). The mean concentrations of B in liver (0.18 mg/kg wet wt), Mn (0.70 mg/kg wet wt), and Na (892.09 mg/kg wet wt) were higher than those in muscle (0.15, 0.11, and 375.55 mg/kg wet wt, respectively). The mean concentrations of Al, Cd, and Pb in muscle tissue were 2.72 mg/kg wet wt and 4.28 and 10.29 μg/kg wet wt, and those in liver tissue were 31.31 mg/kg wet wt and 612.91 and 232.08 μg/kg wet wt, respectively. When comparing the two fish species, the muscle tissue of M. surmuletus has significantly higher concentrations (P < 0.05) of Al, B, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Sr, and Zn than did P. prayensis muscle, whereas the concentrations of Cd and V were significantly higher (P < 0.05) in P. prayensis muscle. Toxicological assessment of Cd and Pb concentrations was performed using the maximum limits set by the European Commission Regulations 1881/2006 and 629/2008 for muscle tissue (50 and 300 μg/kg wet wt, respectively). The concentrations of Cd and Pb in muscle detected in the present study for all the analyzed examples of M. surmuletus and P. prayensis were lower than the maximums established for muscle tissue by European legislation. Therefore, consumption of the muscle of these fish is considered safe in terms of Al, Cd, and Pb concentrations. However, the consumption of liver tissue should be avoided because of its high levels

  20. Seismicity patterns during a period of inflation at Sierra Negra volcano, Galápagos Ocean Island Chain

    Science.gov (United States)

    Davidge, Lindsey; Ebinger, Cynthia; Ruiz, Mario; Tepp, Gabrielle; Amelung, Falk; Geist, Dennis; Coté, Dustin; Anzieta, Juan

    2017-03-01

    Basaltic shield volcanoes of the western Galápagos islands are among the most rapidly deforming volcanoes worldwide, but little was known of the internal structure and brittle deformation processes accompanying inflation and deflation cycles. A 15-station broadband seismic array was deployed on and surrounding Sierra Negra volcano, Galápagos from July 2009 through June 2011 to characterize seismic strain patterns during an inter-eruption inflation period and to evaluate single and layered magma chamber models for ocean island volcanoes. We compare precise earthquake locations determined from a 3D velocity model and from a double difference cluster method. Using first-motion of P-arrivals, we determine focal mechanisms for 8 of the largest earthquakes (ML ≤ 1.5) located within the array. Most of the 2382 earthquakes detected by the array occurred beneath the broad (∼9 km-wide) Sierra Negra caldera, at depths from surface to about 8 km below sea level. Although outside our array, frequent and larger magnitude (ML ≤ 3.4) earthquakes occurred at Alcedo and Fernandina volcano, and in a spatial cluster beneath the shallow marine platform between Fernandina and Sierra Negra volcanoes. The time-space relations and focal mechanism solutions from a 4-day long period of intense seismicity June 4-9, 2010 along the southeastern flank of Sierra Negra suggests that the upward-migrating earthquake swarm occurred during a small volume intrusion at depths 5-8 km subsurface, but there was no detectable signal in InSAR data to further constrain geometry and volume. Focal mechanisms of earthquakes beneath the steep intra-caldera faults and along the ring fault system are reverse and strike-slip. These new seismicity data integrated with tomographic, geodetic, and petrological models indicate a stratified magmatic plumbing system: a shallow sill beneath the large caldera that is supplied by magma from a large volume deeper feeding system. The large amplitude inter

  1. An exploration for deep-sea fish sounds off Vancouver Island from the NEPTUNE Canada ocean observing system

    Science.gov (United States)

    Wall, Carrie C.; Rountree, Rodney A.; Pomerleau, Corinne; Juanes, Francis

    2014-01-01

    Our understanding of the significance of sound production to the ecology of deep-sea fish communities has improved little since anatomical surveys in the 1950s first suggested that sound production is widespread among slope-water fishes. The recent implementation of cabled ocean observatory networks around the world that include passive acoustic recording instruments provides scientists an opportunity to search for evidence of deep-sea fish sounds. We examined deep-sea acoustic recordings made at the NEPTUNE Canada Barkley Canyon Axis Pod (985 m) located off the west coast of Vancouver Island in the Northeast Pacific between June 2010 and May 2011 to determine the presence of fish sounds. A subset of over 300 5-min files was examined by selecting one day each month and analyzing one file for each hour over the 24 h day. Despite the frequent occurrence of marine mammal sounds, no examples of fish sounds were identified. However, we report examples of isolated unknown sounds that might be produced by fish, invertebrates, or more likely marine mammals. This finding is in direct contrast to recent smaller studies in the Atlantic where potential fish sounds appear to be more common. A review of the literature indicates 32 species found off British Columbia that potentially produce sound could occur in depths greater than 700 m but of these only Anoplopoma fimbria and Coryphaenoides spp. have been previously reported at the site. The lack of fish sounds observed here may be directly related to the low diversity and abundance of fishes present at the Barkley Canyon site. Other contributing factors include possible masking of low amplitude biological signals by self-generated noise from the platform instrumentation and ship noise. We suggest that examination of data both from noise-reduced ocean observatories around the world and from dedicated instrument surveys designed to search for deep-sea fish sounds to provide a larger-scale, more conclusive investigation into the

  2. Satellite remote sensing of the island mass effect on the Sub-Antarctic Kerguelen Plateau, Southern Ocean

    Science.gov (United States)

    Jena, Babula

    2016-09-01

    The presence of the Kerguelen Plateau and surrounding bathymetric features has a strong influence on the persistently eastward flowing Antarctic Circumpolar Current (ACC), resulting in enhancement of surface chlorophyll-a (Chl- a) in the downstream section of the plateau along the polar front (PF). The phenomenon is reported in this paper as the island mass effect (IME). Analysis of climatological Chl- a datasets from Aqua- Moderate Resolution Imaging Spectroradiometer (Aqua- MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) shows distinct bloomy plumes (Chl- a>0.5 mg/m3) during austral spring-summer spreading as far as ~1800 km offshore up to 98°E along the downstream of the north Kerguelen Plateau (NKP). Similar IME phenomena is apparent over the south Kerguelen Plateau (SKP) with the phytoplankton bloom extending up to 96.7°E, along the southern boundary of ACC. The IME phenomena are pronounced only during austral spring-summer period with the availability of light and sedimentary source of iron from shallow plateau to sea surface that fertilizes the mixed layer. The NKP bloom peaks with a maximum areal extent of 1.315 million km2 during December, and the SKP bloom peaks during January with a time lag of one month. The blooms exist for at least 4 months of a year and are significant both as the base of regional food web and for regulating the biogeochemical cycle in the Southern Ocean. Even though the surface water above the Kerguelen Plateau is rich in Chl- a, an exception of an oligotrophic condition dominated between NKP and SKP due to apparent intrusion of iron limited low phytoplankton regime waters from the Enderby basin through the northeastward Fawn Trough Current.

  3. Chikungunya fever: a clinical and virological investigation of outpatients on Reunion Island, South-West Indian Ocean.

    Science.gov (United States)

    Thiberville, Simon-Djamel; Boisson, Veronique; Gaudart, Jean; Simon, Fabrice; Flahault, Antoine; de Lamballerie, Xavier

    2013-01-01

    Chikungunya virus (CHIKV) is responsible for acute febrile polyarthralgia and, in a proportion of cases, severe complications including chronic arthritis. CHIKV has spread recently in East Africa, South-West Indian Ocean, South-Asia and autochthonous cases have been reported in Europe. Although almost all patients are outpatients, medical investigations mainly focused on hospitalised patients. Here, we detail clinico-biological characteristics of Chikungunya (CHIK) outpatients in Reunion Island (2006). 76 outpatients with febrile arthralgia diagnosed within less than 48 hours were included by general practitioners during the CuraChik clinical trial. CHIK was confirmed in 54 patients and excluded in 22. A detailed clinical and biological follow-up was organised, that included analysis of viral intrahost diversity and telephone survey until day 300. The evolution of acute CHIK included 2 stages: the 'viral stage' (day 1-day 4) was associated with rapid decrease of viraemia and improvement of clinical presentation; the 'convalescent stage' (day 5-day 14) was associated with no detectable viraemia but a slower clinical improvement. Women and elderly had a significantly higher number of arthralgia at inclusion and at day 300. Based on the study clinico-biological dataset, scores for CHIK diagnosis in patients with recent febrile acute polyarthralgia were elaborated using arthralgia on hands and wrists, a minor or absent myalgia and the presence of lymphopenia (<1G/L) as major orientation criteria. Finally, we observed that CHIKV intra-host genetic diversity increased over time and that a higher viral amino-acid complexity at the acute stage was associated with increased number of arthralgia and intensity of sequelae at day 300. This study provided a detailed picture of clinico-biological CHIK evolution at the acute phase of the disease, allowed the elaboration of scores to assist CHIK diagnosis and investigated for the first time the impact of viral intra-host genetic

  4. 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

  5. 含倾斜砂土夹层的人工岛地震液化灾害分析%Analyses of seismic liquefaction induced disaster in artificial island with sloping sand layer

    Institute of Scientific and Technical Information of China (English)

    胡记磊; 唐小微; 白旭; 张西文

    2015-01-01

    Liquefaction due to strong earthquake easily causes permanent displacement and strain of sloping sand layer in the fundament and induces the phenomena of flow slides,and then brings serious damages to the superstructure. Considering sloping sand layers' gradient, thickness, depth and seawater level synthetically, a two-dimensional offshore artificial island model was simulated numerically by FE-FD coupling finite element analysis method.The experimental results indicate that these four influence factors have different effects on the large deformation of artificial island in the course of seismic liquefaction.The influence of gradient is the greatest,and the influence of seawater level is the most non-obvious,and especially,its effect on excess pore water pressure is very small. Lateral spreading of artificial island j ust occurs after total liquefaction of saturated sloping sand layer in the course of seismic,which is a limit slide along the slope during a period of time.Its degree of damage is much bigger than that of damage induced by liquefaction of horizontal sand layer,and it easily causes serious differential settlement and damage of revetment of artificial island. These analytical results can provide reference for hazard evaluation of offshore engineering due to seismic liquefaction.%强地震易造成地基中倾斜砂土夹层液化后产生永久变形和位移,并诱发流滑现象,进而对上部结构产生严重破坏。基于 FE-FD耦合有限元方法,综合考虑倾斜砂土夹层的坡度、厚度、埋深以及海水水位因素,对某近海人工岛二维结构模型进行了数值模拟分析。结果表明:砂土层的坡度、厚度、埋深以及水位因素对人工岛的地震液化灾害有着不同程度的影响,其中坡度的影响最显著,而水位的影响最不明显,特别是水位对超孔隙水压力增长的影响非常小。人工岛的侧向扩展是在地震过程中饱和倾斜砂土夹层完全液化被

  6. Oceanographic Station Data from bottle casts from the ICE ISLAND as part of the International Decade of Ocean Exploration / International Ocean Studies / First Dynamic Response and Kinematics Experiment in the Drake Passage (IDOE/ISOS/FDRAKE) from 12 September 1974 to 06 October 1974 (NODC Accession 7700357)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Station Data were collected from bottle casts from the ICE ISLAND from 12 September 1974 to 06 October 1974. Data were collected by Oregon State...

  7. Biodiversity of Pigmented Fungi Isolated from Marine Environment in La Réunion Island, Indian Ocean: New Resources for Colored Metabolites

    Directory of Open Access Journals (Sweden)

    Mireille Fouillaud

    2017-07-01

    Full Text Available Marine ecosystems cover about 70% of the planet surface and are still an underexploited source of useful metabolites. Among microbes, filamentous fungi are captivating organisms used for the production of many chemical classes of secondary metabolites bound to be used in various fields of industrial application. The present study was focused on the collection, isolation, screening and genotyping of pigmented filamentous fungi isolated from tropical marine environments around La Réunion Island, Indian Ocean. About 150 micromycetes were revived and isolated from 14 marine samples (sediments, living corals, coral rubble, sea water and hard substrates collected in four different locations. Forty-two colored fungal isolates belonging to 16 families, 25 genera and 31 species were further studied depending on their ability to produce pigments and thus subjected to molecular identification. From gene sequence analysis, the most frequently identified colored fungi belong to the widespread Penicillium, Talaromyces and Aspergillus genera in the family Trichocomaceae (11 species, then followed by the family Hypocreaceae (three species. This study demonstrates that marine biotopes in La Réunion Island, Indian Ocean, from coral reefs to underwater slopes of this volcanic island, shelter numerous species of micromycetes, from common or uncommon genera. This unstudied biodiversity comes along with the ability for some fungal marine inhabitants, to produce a range of pigments and hues.

  8. Genus Gambierdiscus in the Canary Islands (NE Atlantic Ocean) with description of Gambierdiscus silvae sp. nov., a new potentially toxic epiphytic benthic dinoflagellate.

    Science.gov (United States)

    Fraga, Santiago; Rodríguez, Francisco

    2014-12-01

    Species of the dinoflagellate genus Gambierdiscus are the cause of Ciguatera Fish Poisoning, common in tropical areas. Nevertheless, until recently this syndrome was not reported in the NE Atlantic Ocean. A new photosynthetic dinoflagellate species, Gambierdiscus silvae sp. nov. is described based on samples taken from tide pools on rocky shores of the Canary Islands (NE Atlantic Ocean). Its morphology was studied by light and scanning electron microscopy. The new species is anterioposteriorly compressed, lenticular in shape with an epitheca slightly higher than the hypotheca. It is round in apical view and has a thick smooth theca with many scattered pores. Plate formula is Po, 4', 0a, 6″, 6c, 6s?, 5'″, 0p, 2″″. Plate 2' is hatchet-shaped and Plate 2″″ is very wide and the largest of the hypotheca. Phylogenies inferred from the large subunit nuclear rRNA showed that three G. silvae strains clustered in a well supported sister clade to G. polynesiensis, distinct from the other species. G. australes was observed for the first time in the Atlantic, together with G. excentricus already reported from these islands. This work increases the number of Gambierdiscus species described and shows their unexpected diversity in the Canary Islands.

  9. Turbidity current activity along the flanks of a volcanic edifice: The Mafate volcaniclastic complex, La Réunion Island, Indian Ocean

    Science.gov (United States)

    Mazuel, Aude; Sisavath, Emmanuelle; Babonneau, Nathalie; Jorry, Stephan J.; Bachèlery, Patrick; Delacourt, Christophe

    2016-04-01

    Recent marine geophysical surveys reveal the existence of well-developed volcaniclastic deep-sea fans around La Réunion Island, Indian Ocean. The Mafate turbidite complex, located in the northwestern part of the island, is a large sedimentary system formed by two coalescent-like volcaniclastic deep-sea fans: the Mafate fan and the Saint-Denis fan. They are both connected to terrestrial rivers supplying sediment produced by erosion on the island, particularly during austral summer cyclonic floods. Through the integration of marine geophysical data (including bathymetry, backscatter multibeam sounder images, TOBI side-scan sonar images and seismic reflection profiles) and piston cores, a submarine morpho-sedimentary map of the surface architecture of the Mafate and Saint-Denis turbidite systems has been established. The systems are divided in three main domains: deep canyons in the proximal area, a channel network in the medial area, and distal depositional lobes on the abyssal sea floor. Two large sediment wave fields also formed as a result of the volcaniclastic turbidity currents. Three piston cores collected along the Mafate complex provide information on the sedimentary processes in this area over the last 25 ka. The record of turbidite events in these cores is interpreted in terms of volcanic and climatic changes that could have controlled the sediment transfer to the deep ocean.

  10. Transects_OpenOcean.shp - Digital Shoreline Analysis System version 4.3 Transects with Linear Regression Rate Calculations for the Open Ocean coast of Dauphin Island, Alabama.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rates of shoreline change for Dauphin Island, Alabama were generated for three analysis periods, using two different shoreline proxy datasets. Mean High Water line...

  11. 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

  12. Cross-Mating Compatibility and Competitiveness among Aedes albopictus Strains from Distinct Geographic Origins - Implications for Future Application of SIT Programs in the South West Indian Ocean Islands.

    Science.gov (United States)

    Damiens, David; Lebon, Cyrille; Wilkinson, David A; Dijoux-Millet, Damien; Le Goff, Gilbert; Bheecarry, Ambicadutt; Gouagna, Louis Clément

    2016-01-01

    The production of large numbers of males needed for a sustainable sterile insect technique (SIT) control program requires significant developmental and operational costs. This may constitute a significant economic barrier to the installation of large scale rearing facilities in countries that are undergoing a transition from being largely dependent on insecticide use to be in a position to integrate the SIT against Aedes albopictus. Alternative options available for those countries could be to rely on outsourcing of sterile males from a foreign supplier, or for one centralised facility to produce mosquitoes for several countries, thus increasing the efficiency of the mass-rearing effort. However, demonstration of strain compatibility is a prerequisite for the export of mosquitoes for transborder SIT applications. Here, we compared mating compatibility among Ae. albopictus populations originating from three islands of the South Western Indian Ocean, and assessed both insemination rates and egg fertility in all possible cross-mating combinations. Furthermore, competitiveness between irradiated and non-irradiated males from the three studied strains, and the subsequent effect on female fertility were also examined. Although morphometric analysis of wing shapes suggested phenoptypic differences between Ae. albopictus strains, perfect reproductive compatibility between them was observed. Furthermore, irradiated males from the different islands demonstrated similar levels of competitiveness and induced sterility when confronted with fertile males from any of the other island populations tested. In conclusion, despite the evidence of inter-strain differences based on male wing morphology, collectively, our results provide a new set of expectations for the use of a single candidate strain of mass-reared sterile males for area-wide scale application of SIT against Ae. albopictus populations in different islands across the South Western Indian Ocean. Cross

  13. Cytoplasmic Incompatibility as a Means of Controlling Culex pipiens quinquefasciatus Mosquito in the Islands of the South-Western Indian Ocean

    Science.gov (United States)

    Atyame, Célestine M.; Pasteur, Nicole; Dumas, Emilie; Tortosa, Pablo; Tantely, Michaël Luciano; Pocquet, Nicolas; Licciardi, Séverine; Bheecarry, Ambicadutt; Zumbo, Betty; Weill, Mylène; Duron, Olivier

    2011-01-01

    The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands. PMID:22206033

  14. Cross-Mating Compatibility and Competitiveness among Aedes albopictus Strains from Distinct Geographic Origins - Implications for Future Application of SIT Programs in the South West Indian Ocean Islands

    Science.gov (United States)

    Damiens, David; Lebon, Cyrille; Wilkinson, David A.; Dijoux-Millet, Damien; Le Goff, Gilbert; Bheecarry, Ambicadutt; Gouagna, Louis Clément

    2016-01-01

    The production of large numbers of males needed for a sustainable sterile insect technique (SIT) control program requires significant developmental and operational costs. This may constitute a significant economic barrier to the installation of large scale rearing facilities in countries that are undergoing a transition from being largely dependent on insecticide use to be in a position to integrate the SIT against Aedes albopictus. Alternative options available for those countries could be to rely on outsourcing of sterile males from a foreign supplier, or for one centralised facility to produce mosquitoes for several countries, thus increasing the efficiency of the mass-rearing effort. However, demonstration of strain compatibility is a prerequisite for the export of mosquitoes for transborder SIT applications. Here, we compared mating compatibility among Ae. albopictus populations originating from three islands of the South Western Indian Ocean, and assessed both insemination rates and egg fertility in all possible cross-mating combinations. Furthermore, competitiveness between irradiated and non-irradiated males from the three studied strains, and the subsequent effect on female fertility were also examined. Although morphometric analysis of wing shapes suggested phenoptypic differences between Ae. albopictus strains, perfect reproductive compatibility between them was observed. Furthermore, irradiated males from the different islands demonstrated similar levels of competitiveness and induced sterility when confronted with fertile males from any of the other island populations tested. In conclusion, despite the evidence of inter-strain differences based on male wing morphology, collectively, our results provide a new set of expectations for the use of a single candidate strain of mass-reared sterile males for area-wide scale application of SIT against Ae. albopictus populations in different islands across the South Western Indian Ocean. Cross

  15. Mid-Holocene vertebrate bone Concentration-Lagerstätte on oceanic island Mauritius provides a window into the ecosystem of the dodo ( Raphus cucullatus)

    Science.gov (United States)

    Rijsdijk, Kenneth F.; Hume, Julian P.; Bunnik, Frans; Florens, F. B. Vincent; Baider, Claudia; Shapiro, Beth; van der Plicht, Johannes; Janoo, Anwar; Griffiths, Owen; van den Hoek Ostende, Lars W.; Cremer, Holger; Vernimmen, Tamara; De Louw, Perry G. B.; Bholah, Assenjee; Saumtally, Salem; Porch, Nicolas; Haile, James; Buckley, Mike; Collins, Matthew; Gittenberger, Edmund

    2009-01-01

    Although the recent history of human colonisation and impact on Mauritius is well documented, virtually no records of the pre-human native ecosystem exist, making it difficult to assess the magnitude of the changes brought about by human settlement. Here, we describe a 4000-year-old fossil bed at Mare aux Songes (MAS) in south-eastern Mauritius that contains both macrofossils (vertebrate fauna, gastropods, insects and flora) and microfossils (diatoms, pollen, spores and phytoliths). With >250 bone fragments/m 2 and comprising 50% of all known extinct and extant vertebrate species ( ns = 44) of Mauritius, MAS may constitute the first Holocene vertebrate bone Concentration-Lagerstätte identified on an oceanic volcanic island. Fossil remains are dominated by extinct giant tortoises Cylindraspis spp. (63%), passerines (˜10%), small bats (7.8%) and dodo Raphus cucullatus (7.1%). Twelve radiocarbon ages [four of them duplicates] from bones and other material suggest that accumulation of fossils took place within several centuries. An exceptional combination of abiotic conditions led to preservation of bones, bone collagen, plant tissue and microfossils. Although bone collagen is well preserved, DNA from dodo and other Mauritian vertebrates has proved difficult. Our analysis suggests that from ca 4000 years ago (4 ka), rising sea levels created a freshwater lake at MAS, generating an oasis in an otherwise dry environment which attracted a diverse vertebrate fauna. Subsequent aridification in the south-west Indian Ocean region may have increased carcass accumulation during droughts, contributing to the exceptionally high fossil concentration. The abundance of floral and faunal remains in this Lagerstätte offers a unique opportunity to reconstruct a pre-human ecosystem on an oceanic island, providing a key foundation for assessing the vulnerability of island ecosystems to human impact.

  16. Circum-Pacific accretion of oceanic terranes to continental blocks: accretion of the Early Permian Dun Mountain ophiolite to the E Gondwana continental margin, South Island, New Zealand

    Science.gov (United States)

    Robertson, Alastair

    2016-04-01

    Accretionary orogens, in part, grow as a result of the accretion of oceanic terranes to pre-existing continental blocks, as in the circum-Pacific and central Asian regions. However, the accretionary processes involved remain poorly understood. Here, we consider settings in which oceanic crust formed in a supra-subduction zone setting and later accreted to continental terranes (some, themselves of accretionary origin). Good examples include some Late Cretaceous ophiolites in SE Turkey, the Jurassic Coast Range ophiolite, W USA and the Early Permian Dun Mountain ophiolite of South Island, New Zealand. In the last two cases, the ophiolites are depositionally overlain by coarse clastic sedimentary rocks (e.g. Permian Upukerora Formation of South Island, NZ) that then pass upwards into very thick continental margin fore-arc basin sequences (Great Valley sequence, California; Matai sequence, South Island, NZ). Field observations, together with petrographical and geochemical studies in South Island, NZ, summarised here, provide evidence of terrane accretion processes. In a proposed tectonic model, the Early Permian Dun Mountain ophiolite was created by supra-subduction zone spreading above a W-dipping subduction zone (comparable to the present-day Izu-Bonin arc and fore arc, W Pacific). The SSZ oceanic crust in the New Zealand example is inferred to have included an intra-oceanic magmatic arc, which is no longer exposed (other than within a melange unit in Southland), but which is documented by petrographic and geochemical evidence. An additional subduction zone is likely to have dipped westwards beneath the E Gondwana margin during the Permian. As a result, relatively buoyant Early Permian supra-subduction zone oceanic crust was able to dock with the E Gondwana continental margin, terminating intra-oceanic subduction (although the exact timing is debatable). The amalgamation ('soft collision') was accompanied by crustal extension of the newly accreted oceanic slab, and

  17. 海洋岛屿特有种的分化形成与维持%Research on differentiation and speciation of the oceanic island endemics

    Institute of Scientific and Technical Information of China (English)

    徐卫祥; 王中生; 王志科; 马元屾; 杨琳璐; 安树青

    2012-01-01

    岛屿特有物种因具有种群间海域隔离、分布边界清晰、分布范围狭窄及种群规模较小等特点,已成为岛屿生物地理学研究的模式种.综合分析岛屿特有种的相关研究案例,将岛屿特有物种分化和形成过程概括为4个阶段:向岛屿迁移、种群建立、扩大分布区域以及适应性辐射等.岛屿生态系统中特有种分化与形成的驱动力主要包括:(1)海域隔离降低有效基因流;(2)邻近岛屿或大陆对岛屿的多重侵居;(3)建群种适应不同生境的辐射分化;(4)熔岩流等突发地质事件引起的建群种分化;(5)瓶颈效应或建立者效应等驱动新物种形成.尽管岛屿拥有丰富的特有物种多样性,但由于受基因流阻隔、遗传漂变、小种群瓶颈效应及稀有等位基因流失等因素的影响,岛屿特有物种比陆地物种更易于濒危或灭绝.“物种恢复工程”与生态系统水平上的生境保护工程的同步开展将有利于岛屿特有物种及岛屿生态系统的保育.%Due to the oceanic geographic isolation, distinctive distribution boundary, narrow distribution range and small population size, island endemics have become the model species for island biogeography research. According to the studies related to island endemics, we summarized the course of differentiation and speciation of the oceanic island endemics into four stages: migration into new islands, establishment of populations, enlargement of distribution regions and adaptive changes and/or radiations. There were five kinds of forces driving these processes: ( 1) the reduced gene flow by o-ceanic isolation; (2) multiple colonization from nearby islands or mainland; (3) adaptive radiation in different habitats; (4) differentiation caused by sudden geological events such as lava flow; (5) speciation conduced by bottleneck effect or founder effect. Though islands have rich diversity of endemics, these island species have greater tendency to be

  18. Dredging Research Program. Results of Monitoring the Disposal Berm at Sand Island, Alabama. Report 1. Construction and First Year’s Response

    Science.gov (United States)

    1990-12-01

    22M MOBLE AL. 3NASIO Figure 10. Recovery card attached to each SBD conventional 7-g attached weight results in near neutral buoyancy. These SBD’s move...PELICAN POINT MOBLE POINT GULF SHORES 3 MAR 87 -m 20 19MAR87 ? 17 31 MAR87 D , HQ 19z 15APR87 n- __12 cr" 5MAY87 0 15 II AUG 87 12 z 20 OCT 87 6 I DEC... Technology Laboratory, MS. Hallermeier, R. J. 1980 (Aug). "Sand Motion Initiation by Water Waves: Two Asymptotes," Journal of the Waterway. Port, Coastal and

  19. 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...

  20. Planonasus parini n. g. and n. sp., a new genus and species of false cat sharks (Carchariniformes, Pseudotriakidae) from the deep northwestern Indian Ocean off Socotra Islands.

    Science.gov (United States)

    Weigmann, Simon; Stehmann, Matthias F W; Thiel, Ralf

    2013-01-29

    A new genus and species of the carcharhiniform family Pseudotriakidae is described based on three specimens caught near the Socotra Islands in the northwestern Indian Ocean. The first specimen and holotype of Planonasus parini g. n. and sp. n. was caught during cruise 17 of RV 'Vityaz' in 1988/89 along the deep western Indian Ocean. Two further specimens of the new genus and species were caught somewhat later by commercial trawlers close to the locality of the holotype. The new genus differs from the two other pseudotriakid genera Gollum and Pseudotriakis by the presence of oral papillae, the absence of nicitating eyelids, a longer head, an intermediate prenarial snout length, an intermediate number of tooth rows per jaw, a first dorsal fin of intermediate height and length and with a white free rear tip, a caudal peduncle of inter-mediate length, and fewer vertebrae.

  1. Reducing Environmental Impact of Aggregate Excavation in Small Tropic Pacific Islands

    Institute of Scientific and Technical Information of China (English)

    薛春汀

    2004-01-01

    Excavating sands and gravel on land in combination with constructing reservoirs for storing fresh water is an ideal approach in atolls. Appropriate mining of gravel from the prograding gravel beach is acceptable. Digging reef rock close to the edge of the wide ocean reef flat without surface loose sediments on it or sand beach can be accepted. Excavating sand from some depths in lagoon is a scientific approachparticularly important for urbanized atolls. However, selecting appropriate sites for mining sand other than at some depths in lagoon is suitable to rural islands without dense populations. These sites include up drift side of long groin on the reef fiat,partly filled access channel-port, outlet of artificial channel and lagoon margin on the prograding coast.

  2. Primary productivity and other data from bottle casts from the USCGC STATEN ISLAND and other platforms in the North Pacific Ocean in support of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 07 August 1974 to 06 May 1979 (NODC Accession 8000599)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Primary productivity and other data were collected from bottle casts from the USCGC STATEN ISLAND and other platforms in the North Pacific Ocean from 07 August 1974...

  3. Beach Sand Supply and Transport at Kunduchi in Tanzania and ...

    African Journals Online (AJOL)

    OCEAN. Mombasa. Dar es. Salaam. KUNDUCHI. KENYA. TANZANIA ... Figure 2. a) Reef-platform transects at Bamburi. b) Beach plain sand ..... comprised coral debris covered by turf algae .... and ocean acidification should not be ruled.

  4. Coeval giant landslides in the Canary Islands: Implications for global, regional and local triggers of giant flank collapses on oceanic volcanoes

    Science.gov (United States)

    Boulesteix, Thomas; Hildenbrand, Anthony; Soler, Vicente; Quidelleur, Xavier; Gillot, Pierre-Yves

    2013-05-01

    Giant landslides are an important part of the evolution of most intra-plate volcanic islands. They often proceed in catastrophic events, likely to generate voluminous debris avalanches and eventually trigger destructive tsunamis. Although knowledge of the timing of their recurrence is a key factor regarding the hazard assessment in coastal environments, only a few of them have been well dated. In this contribution, we focus on the La Orotava event on Tenerife, which we date with the unspiked K-Ar technique, between 534 and 523 ka. Such narrow temporal interval is compatible, within uncertainties, with the age of the Cumbre Nueva collapse on the neighboring island of La Palma. We thus examine here the possible common triggering mechanisms at the global, regional and local scales. Both events occurred shortly after the climax of the oxygen isotopic stage 14, during the rapid transition towards the interglacial stage 13, reinforcing the hypothesis of a control from global paleoclimatic changes on the destabilization of oceanic islands. Intense volcanic pulses at the regional scale also lead to the synchronous overgrowth of several volcanic islands in the archipelago, but coeval destabilization on Tenerife and La Palma appears significantly controlled by the intrinsic morphology of the edifices, with contrasted instability thresholds for shield volcanoes and volcanic ridges respectively. Finally, we propose that the two events may be genetically linked. Dynamic transfer of voluminous debris avalanches during a giant landslide episode can induce isostatic readjustments, generate significant ground acceleration and finally produce a large tsunami, three processes which can concur to trigger large scale flank collapse on a neighboring mature unstable volcanic island.

  5. Understanding large-scale, long-term larval connectivity patterns: The case of the Northern Line Islands in the Central Pacific Ocean

    Science.gov (United States)

    Mari, Lorenzo; Bonaventura, Luca; Storto, Andrea; Melià, Paco; Gatto, Marino; Masina, Simona

    2017-01-01

    Protecting key hotspots of marine biodiversity is essential to maintain ecosystem services at large spatial scales. Protected areas serve not only as sources of propagules colonizing other habitats, but also as receptors, thus acting as protected nurseries. To quantify the geographical extent and the temporal persistence of ecological benefits resulting from protection, we investigate larval connectivity within a remote archipelago, characterized by a strong spatial gradient of human impact from pristine to heavily exploited: the Northern Line Islands (NLIs), including part of the Pacific Remote Islands Marine National Monument (PRI-MNM). Larvae are described as passive Lagrangian particles transported by oceanic currents obtained from a oceanographic reanalysis. We compare different simulation schemes and compute connectivity measures (larval exchange probabilities and minimum/average larval dispersal distances from target islands). To explore the role of PRI-MNM in protecting marine organisms with pelagic larval stages, we drive millions of individual-based simulations for various Pelagic Larval Durations (PLDs), in all release seasons, and over a two-decades time horizon (1991–2010). We find that connectivity in the NLIs is spatially asymmetric and displays significant intra- and inter-annual variations. The islands belonging to PRI-MNM act more as sinks than sources of larvae, and connectivity is higher during the winter-spring period. In multi-annual analyses, yearly averaged southward connectivity significantly and negatively correlates with climatological anomalies (El Niño). This points out a possible system fragility and susceptibility to global warming. Quantitative assessments of large-scale, long-term marine connectivity patterns help understand region-specific, ecologically relevant interactions between islands. This is fundamental for devising scientifically-based protection strategies, which must be space- and time-varying to cope with the

  6. 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.

  7. 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....

  8. "Canary Islands, a volcanic window in the Atlantic Ocean": a 7 year effort of public awareness on volcano hazards and risk management

    Science.gov (United States)

    Rodríguez, Fátima; Calvo, David; Pérez, Nemesio M.; Padrón, Eleazar; Melián, Gladys; Padilla, Germán; Barrancos, José; Hernández, Pedro A.; Asensio-Ramos, María; Alonso, Mar

    2016-04-01

    "Canary Islands: A volcanic window in the Atlantic Ocean" is an educational program born from the need to inform and educate citizens residing in the Canary Islands on the various hazards associated to volcanic phenomena. The Canary Islands is the only territory of Spain that hosts active volcanism, as is shown by the 16 historical eruptions that have occurred throughout this territory, being the last one a submarine eruption taking place on October 12, 2011, offshore El Hierro Island. In the last 7 years, ITER as well as INVOLCAN have been performing an educative program focused on educating to the population about the benefits of a volcanic territory, volcanic hazards, how to reduce volcanic risk and the management of volcanic risk in the Canary Islands. "Canary Islands: A volcanic window in the Atlantic Ocean" consists of three units, the first two dedicated to the IAVCEI/UNESCO videos "Understanding Volcanic Hazards" and "Reducing Volcanic Risk" and the third one dedicated to the management of volcanic risk in the Canary Islands, as well as some other aspects of the volcanic phenomena. Generally the three units are shown consecutively on Tuesday, Wednesday and Thursday. This educative program has been roaming all around the 88 municipalities of the archipelago since this initiative started in 2008. The total number of attendees since then amounts to 18,911 people. The increase of assistance was constant until 2011, with annual percentages of 7.8, 17.1 and 20.9 respectively, regarding to ratio assistant/municipality. Despite the heterogeneity of the audience, the main audience is related to aged people of 45 years and older. This could be related to the memories of the recent eruptions occurred at La Palma Island in 1949 and 1971. It is important to point out that many of those people attending the educative program are representatives of local government (i.e. civil protection). Regarding the interest of the audience, the educational program attendees have

  9. Amphidromy links a newly documented fish community of continental Australian streams, to oceanic islands of the west Pacific.

    Directory of Open Access Journals (Sweden)

    Paul A Thuesen

    Full Text Available BACKGROUND: Indo-Pacific high island streams experience extreme hydrological variation, and are characterised by freshwater fish species with an amphidromous life history. Amphidromy is a likely adaptation for colonisation of island streams following stochastic events that lead to local extirpation. In the Wet Tropics of north-eastern Australia, steep coastal mountain streams share similar physical characteristics to island systems. These streams are poorly surveyed, but may provide suitable habitat for amphidromous species. However, due to their ephemeral nature, common non-diadromous freshwater species of continental Australia are unlikely to persist. Consequently, we hypothesise that coastal Wet Tropics streams are faunally more similar, to distant Pacific island communities, than to nearby faunas of large continental rivers. METHODS/PRINCIPAL FINDINGS: Surveys of coastal Wet Tropics streams recorded 26 species, 10 of which are first records for Australia, with three species undescribed. This fish community is unique in an Australian context in that it contains mostly amphidromous species, including sicydiine gobies of the genera Sicyopterus, Sicyopus, Smilosicyopus and Stiphodon. Species presence/absence data of coastal Wet Tropics streams were compared to both Wet Tropics river networks and Pacific island faunas. ANOSIM indicated the fish fauna of north-eastern Australian coastal streams were more similar to distant Pacific islands (R = 0.76, than to nearby continental rivers (R = 0.98. MAIN CONCLUSIONS/SIGNIFICANCE: Coastal Wet Tropics streams are faunally more similar to distant Pacific islands (79% of species shared, than to nearby continental fauna due to two factors. First, coastal Wet Tropics streams lack many non-diadromous freshwater fish which are common in nearby large rivers. Second, many amphidromous species found in coastal Wet Tropics streams and Indo-Pacific islands remain absent from large rivers of the Wet Tropics

  10. Radiating on oceanic islands: patterns and processes of speciation in the land snail genus Theba (Risso 1826.

    Directory of Open Access Journals (Sweden)

    Carola Greve

    Full Text Available Island radiations have played a major role in shaping our current understanding of allopatric, sympatric and parapatric speciation. However, the fact that species divergence correlates with island size emphasizes the importance of geographic isolation (allopatry in speciation. Based on molecular and morphological data, we investigated the diversification of the land snail genus Theba on the two Canary Islands of Lanzarote and Fuerteventura. Due to the geological history of both islands, this study system provides ideal conditions to investigate the interplay of biogeography, dispersal ability and differentiation in generating species diversity. Our analyses demonstrated extensive cryptic diversification of Theba on these islands, probably driven mainly by non-adaptive allopatric differentiation and secondary gene flow. In a few cases, we observed a complete absence of gene flow among sympatrically distributed forms suggesting an advanced stage of speciation. On the Jandía peninsula genome scans suggested genotype-environment associations and potentially adaptive diversification of two closely related Theba species to different ecological environments. We found support for the idea that genetic differentiation was enhanced by divergent selection in different environments. The diversification of Theba on both islands is therefore best explained by a mixture of non-adaptive and adaptive speciation, promoted by ecological and geomorphological factors.

  11. Superclone Expansion, Long-Distance Clonal Dispersal and Local Genetic Structuring in the Coral Pocillopora damicornis Type β in Reunion Island, South Western Indian Ocean

    Science.gov (United States)

    Gélin, Pauline; Fauvelot, Cécile; Mehn, Vincent; Bureau, Sophie; Rouzé, Héloïse; Magalon, Hélène

    2017-01-01

    The scleractinian coral Pocillopora damicornis type β is known to present a mixed reproduction mode: through sexual reproduction, new genotypes are created, while asexual reproduction insures their propagation. In order to investigate the relative proportion of each reproduction mode in P. damicornis type β populations from Reunion Island, Indian Ocean, clonal propagation along the west coast was assessed through four sampling sites with increasing geographical distance between sites. Coral colonies were sampled either exhaustively, randomly or haphazardly within each site, and genotypic diversity was assessed using 13 microsatellite loci over a total of 510 P. damicornis type β determined a posteriori from their mtDNA haplotype (a 840 bp sequenced fragment of the Open Reading Frame). Overall, 47% of all the sampled colonies presented the same multi-locus genotype (MLG), a superclone, suggesting that asexual propagation is extremely important in Reunion Island. Within each site, numerous MLGs were shared by several colonies, suggesting local clonal propagation through fragmentation. Moreover, some of these MLGs were found to be shared among several sites located 40 km apart. While asexual reproduction by fragmentation seems unlikely over long distances, our results suggest a production of parthenogenetic larvae. Despite shared MLGs, two differentiated clusters were enclosed among populations of the west coast of Reunion Island, revealing the necessity to set up appropriate managing strategies at a local scale. PMID:28068406

  12. Coupled Hf-Nd-Pb isotope co-variations of HIMU oceanic island basalts from Mangaia, Cook-Austral islands, suggest an Archean source component in the mantle transition zone

    Science.gov (United States)

    Nebel, Oliver; Arculus, Richard J.; van Westrenen, Wim; Woodhead, Jon D.; Jenner, Frances E.; Nebel-Jacobsen, Yona J.; Wille, Martin; Eggins, Stephen M.

    2013-07-01

    Although it is widely accepted that oceanic island basalts (OIB) sample geochemically distinct mantle reservoirs including recycled oceanic crust, the composition, age, and locus of these reservoirs remain uncertain. OIB with highly radiogenic Pb isotope signatures are grouped as HIMU (high-μ, with μ = 238U/204Pb), and exhibit unique Hf-Nd isotopic characteristics, defined as ΔɛHf, deviant from a terrestrial igneous rock array that includes all other OIB types. Here we combine new Hf isotope data with previous Nd-Pb isotope measurements to assess the coupled, time-integrated Hf-Nd-Pb isotope evolution of the most extreme HIMU location (Mangaia, French Polynesia). In comparison with global MORB and other OIB types, Mangaia samples define a unique trend in coupled Hf-Nd-Pb isotope co-variations (expressed in 207Pb/206Pb vs. ΔɛHf). In a model employing subducted, dehydrated oceanic crust, mixing between present-day depleted MORB mantle (DMM) and small proportions (˜5%) of a HIMU mantle endmember can re-produce the Hf-Nd-Pb isotope systematics of global HIMU basalts (sensu stricto; i.e., without EM-1/EM-2/FOZO components). An age range of 3.5 to affected by other enriched mantle endmembers (sensu lato). If correct, this requires isolation of parts of the mantle transition zone for >3 Gyr and implies that OIB chemistry can be used to test geodynamic models.

  13. Sand on the move: Post Hurricane Sandy analysis of the coastal sediment budget and bedform migration at Jones Inlet, Long Island, NY

    Science.gov (United States)

    Bales, M. K.; Goff, J. A.; Austin, J. A.; Flood, R. D.; Christensen, B. A.; Browne, C. M.; Saustrup, S.

    2013-12-01

    Hurricane Sandy struck the Northeast coast of the United States on October 29, 2012. Although sustained winds were downgraded to ~70 kts upon landfall, the vast area of the storm along with the direction of impact resulted in major storm-surge flooding and damage, as well as significant changes to the morphology of the coast-line, altering the characteristics of major barrier islands, inlets, and estuaries. A January 2013 post-storm survey aboard the R/V Pritchard, conducted by the University of Texas Institute for Geophysics, Stony Brook University, and Adelphi University, sought to investigate the impact of this post-tropical cyclone on the southwestern coast of Long Island, NY which sustained storm surges of up to 4 m above normal sea level. The objective of this project is to gain insight on the sedimentological volume changes and bathymetrical alterations made on the seafloor within Jones Inlet and the immediate estuaries behind Jones Beach and Long Beach Island. By studying these changes we hope to gain a better understanding of how large cyclonic storms alter sediment volumes and seafloor topography within major inlets and estuarine systems. These modifications can be observed in post-storm multibeam swath bathymetry and backscatter when compared to similar pre-storm data collected in 2010 by Stony Brook University. Post-storm CHIRP seismic reflection data were also collected, in order to define stratigraphic geometries, as well as grab samples to determine grain size distributions and ground truth for the backscatter data. The acoustic reflections imaged in the CHIRP data allow basal reflectors and dominate horizons to be traced throughout the inlet and estuaries. Our analysis focuses on (1) defining and quantifying areas of deposition and erosion from before-and-after bathymetry data; (2) comparing bedform patterns and grain size distributions from before-and-after backscatter and grab sample analysis; and (3) defining stratal geometries of the shallow

  14. The importance of large benthic foraminifera to reef island sediment budget and dynamics at Raine Island, northern Great Barrier Reef

    Science.gov (United States)

    Dawson, John L.; Smithers, Scott G.; Hua, Quan

    2014-10-01

    Low-lying reef islands are among the most vulnerable environments on earth to anthropogenic-induced climate change and sea-level rise over the next century because they are low, composed of unconsolidated sediment that is able to be mobilised by waves and currents, and depend on sediments supplied by reef organisms that are particularly sensitive to environmental changes (e.g. ocean temperatures and chemistry). Therefore, the spatial and temporal links between active carbonate production and island formation and dynamics are fundamental to predicting future island resilience, yet remain poorly quantified. In this paper we present results of a detailed geomorphological and sedimentological study of a reef and sand cay on the northern Great Barrier Reef. We provide an empirical investigation of the temporal linkages between sediment production and reef island development using a large collection of single grain AMS 14C dates. Large benthic foraminifera (LBF) are the single most important contributor to contemporary island sand mass (47%; ranging from 36% to 63%) at Raine Island, reflecting rapid rates of sediment production and delivery. Standing stock data reveal extremely high production rates on the reef (1.8 kg m- 2 yr- 1), while AMS 14C dates of single LBF tests indicate rapid rates of sediment transferral across the reef. We also demonstrate that age is statistically related to preservation and taphonomic grade (severely abraded tests > moderately abraded tests > pristine tests). We construct a contemporary reef and island sediment budget model for Raine Island that shows that LBF (Baculogypsina, Marginopora and Amphistegina) contribute 55% of the sediment produced on the reef annually, of which a large proportion (54%) contribute to the net annual accretion of the island. The tight temporal coupling between LBF growth and island sediment supply combined with the sensitivity of LBF to bleaching and ocean acidification suggests that islands dominated by LBF are

  15. Characterization of the spatial and temporal dynamics of the dengue vector population established in urban areas of Fernando de Noronha, a Brazilian oceanic island.

    Science.gov (United States)

    Regis, Lêda N; Acioli, Ridelane Veiga; Silveira, José Constantino; de Melo-Santos, Maria Alice Varjal; da Cunha, Mércia Cristiane Santana; Souza, Fátima; Batista, Carlos Alberto Vieira; Barbosa, Rosângela Maria Rodrigues; de Oliveira, Cláudia Maria Fontes; Ayres, Constância Flávia Junqueira; Monteiro, Antonio Miguel Vieira; Souza, Wayner Vieira

    2014-09-01

    Aedes aegypti has played a major role in the dramatic expansion of dengue worldwide. The failure of control programs in reducing the rhythm of global dengue expansion through vector control suggests the need for studies to support more appropriated control strategies. We report here the results of a longitudinal study on Ae. aegypti population dynamics through continuous egg sampling aiming to characterize the infestation of urban areas of a Brazilian oceanic island, Fernando de Noronha. The spatial and temporal distribution of the dengue vector population in urban areas of the island was described using a monitoring system (SMCP-Aedes) based on a 103-trap network for Aedes egg sampling, using GIS and spatial statistics analysis tools. Mean egg densities were estimated over a 29-month period starting in 2011 and producing monthly maps of mosquito abundance. The system detected continuous Ae. aegypti oviposition in most traps. The high global positive ovitrap index (POI=83.7% of 2815 events) indicated the frequent presence of blood-fed-egg laying females at every sampling station. Egg density (eggs/ovitrap/month) reached peak values of 297.3 (0 - 2020) in May and 295 (0 - 2140) in August 2012. The presence of a stable Ae. aegypti population established throughout the inhabited areas of the island was demonstrated. A strong association between egg abundance and rainfall with a 2-month lag was observed, which combined with a first-order autocorrelation observed in the series of egg counts can provide an important forecasting tool. This first description of the characteristics of the island infestation by the dengue vector provides baseline information to analyze relationships between the spatial distribution of the vector and dengue cases, and to the development of integrated vector control strategies. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Classifying Pacific islands

    Science.gov (United States)

    Nunn, Patrick D.; Kumar, Lalit; Eliot, Ian; McLean, Roger F.

    2016-12-01

    An earth-science-based classification of islands within the Pacific Basin resulted from the preparation of a database describing the location, area, and type of 1779 islands, where island type is determined as a function of the prevailing lithology and maximum elevation of each island, with an island defined as a discrete landmass composed of a contiguous land area ≥1 ha (0.01 km2) above mean high-water level. Reefs lacking islands and short-lived (ocean setting as well as the biological attributes of Pacific islands. It may also be used in spatial assessments of second-order phenomena associated with the islands, such as their vulnerability to various disasters, coastal erosion, or ocean pollution as well as human populations, built infrastructure and natural resources.

  17. Surficial geology of the sea floor in Central Rhode Island Sound Southeast of Point Judith, Rhode Island

    Science.gov (United States)

    McMullen, K.Y.; Poppe, L.J.; Ackerman, S.D.; Blackwood, D.S.; Schaer, J.D.; Nadeau, M.A.; Wood, D.A.

    2011-01-01

    The U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are working together to study sea-floor environments off the northeast coast of the United States. During 2008, NOAA survey H11996 collected multibeam echosounder data in a 65-square kilometer area in central Rhode Island Sound, southeast of Point Judith, Rhode Island. During 2010, the USGS collected bottom photographs and sediment samples from 25 stations in this study area. The bathymetry, photography, and sediment data are used to interpret sea-floor features including scour depressions, sand waves, trawl marks, and dredge spoils. Scour depressions cover the bathymetric highs in much of the study area. Sand waves are located mostly in the southwest, and trawl marks tend to be in the northern regions. Dredge spoils are located at a disposal site in a bathymetric low in the western end of the study area. Most stations have a sea-floor surface of sand or silty sand, but eight of the stations have boulders to pea-sized gravel or gravelly sediment on the surface. Photographs show sandy areas typically have scattered burrows, shells, amphipod communities, and worm tubes. Boulders and cobbles are commonly overgrown with hydrozoans and anemones.

  18. Morphological modifications of the Kerguelen Islands (South Indian Ocean) in response to Neogene climate change: evidence from 40Ar/39Ar and (U-Th)/He thermochronology

    Science.gov (United States)

    Ahadi, Floriane; Delpech, Guillaume; Gautheron, Cécile; Nomade, Sébastien; Pinna-jamme, Rosella; Ponthus, Léandre; Guillaume, Damien

    2016-04-01

    The processes driving erosion in geodynamic contexts in which regional tectonics is of minor importance, such as in oceanic islands, can be seen as a combination of positive/negative retroactions between climate change, isostasy or dynamic topography. The Kerguelen Islands (48-50° S, 68.5-70.5° E) are of particular interest to understand the impact of Cenozoïc climatic variations on the long-term geomorphological evolution of emerged reliefs at mid-latitudes. The Kerguelen Islands (6700 km2) are the emerged part of the vast Kerguelen oceanic plateau and reach a maximum height of 1852m asl. The archipelago is mostly made up of Oligocene basaltic traps (≈25 Ma) up to 1000m asl that are cross-cut by a dense network of large and deep valleys. The impact of glacial erosion during the last Quaternary glaciations on the landscape morphology is attested by the occurrence of U-shaped valleys, abundant moraines, erratic blocs and glacial lakes, as well as remnants of glaciers. Numerous plutonic complexes of various age (25-4.5 Ma) locally intrude theses traps and cover about 15% of the main island's surface; the largest being located in the Rallier du Baty peninsula (800 km2). This plutonic complex is mainly constituted of syenites with minor occurrence of gabbros and monzonites. The southern part of this complex has a laccolith structure with satellites plutons and formed between 13.7 and 8.0 Ma. The cooling history of syenites from the Rallier du Baty plutonic complex was investigated in order to identify one or several denudation periods and to understand the potential role of climate change on the geomorphological evolution of the islands since the Oligocene. We conducted the first thermochronological study on the Kerguelen Islands using the biotite 40Ar/39Ar thermochronometer and the apatite (U-Th)/He thermochronometer (AHe). The 40Ar/39Ar ages range from 9.44 ± 0.13 Ma to 13.84 ± 0.07 Ma for the various parts of the southern complex. These ages are identical to

  19. Sands styrke

    DEFF Research Database (Denmark)

    Jacobsen, H. Moust; Jørgensen, Mogens B.; Poulsen, H. Serup

    1975-01-01

    På grundlag af triaxialforsøg med D=7 og 20 cm og varierende højde på løse og faste lejringer af Blokhussand kan effekten af varierende højde-breddeforhold og spændingsniveau samt skalaeffekten bestemmes. Ved sammenligning med pladeforsøg med overfladelast op til 8 t/m2 kan den almindelige fremga...... fremgangsmåde ved bæreevneberegninger på sand undersøges....

  20. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Science.gov (United States)

    2010-07-01

    ..., in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation...; bombing and gunnery target area. (a) The danger zone. From Punta Resaca on the north coast of Culebra at... danger zone is subject to use as a target area for bombing and gunnery practice. It will be open to...

  1. 33 CFR 334.1410 - Pacific Ocean, at Makapuu Point, Waimanalo, Island of Oahu, Hawaii, Makai Undersea Test Range.

    Science.gov (United States)

    2010-07-01

    ..., Waimanalo, Island of Oahu, Hawaii, Makai Undersea Test Range. 334.1410 Section 334.1410 Navigation and..., Makai Undersea Test Range. (a) The restricted area. The waters within an area beginning at a point in..., the operating officials of the Makai Test Range will mark in a conspicuous manner the location of...

  2. 1957 Aleutian Islands, USA Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The magnitude 8.6 (Mw) earthquake occurred south of the Andreanof Islands, in the Aleutian Islands. It generated an 8-meter tsunami that did great damage on Adak...

  3. Manta rays in the Marquesas Islands: first records of Manta birostris in French Polynesia and most easterly location of Manta alfredi in the Pacific Ocean, with notes on their distribution.

    Science.gov (United States)

    Mourier, J

    2012-11-01

    Based on direct observations of free-ranging specimens, the giant manta ray Manta birostris is reported from the Marquesas Islands, the first sighting in French Polynesia. Sightings of its sister species, the reef manta ray Manta alfredi, are also reported at the most easterly location in the Pacific Ocean. Preliminary individual identification as well as notes on their distribution are also reported.

  4. Tectonic implications for the occurrence of ocean floor, hotspot, and island arc materials within accretionary prisms: Examples from the Mesozoic-Cenozoic NW Pacific Rim

    Science.gov (United States)

    Ogawa, Y.; Hirano, N.; Hirano, N.; Taniguchi, H.; Taniguchi, H.; Taniguchi, H.

    2001-12-01

    On-land Mesozoic-Cenozoic accretionary prisms exposed in Japan commonly have basaltic rocks incorporated as blocks into melanges or fault zones during a prolonged history of subduction and/or obduction. Chemical signatures of these basaltic rocks and their mode of occurrence with sedimentary covers and/or associated sedimentary rocks indicate that most of these isolated small basaltic blocks consistently display a WPB chemistry, whereas large slabs of basaltic rocks around the Izu Arc collision zone show MORB chemistry with rare examples of IAT, BABB, and/or WPB affinities. Comparing with the present uniformitarian examples of convergent plate boundaries in the western Pacific that we know through the DSDP and ODP projects and submersible and seismic surveys, we can interpret some of the basaltic material with WPB affinity in the Japanese accretionary prisms as relict edifices of seamounts with hotspot origin. These hotspot-related basaltic rocks are commonly associated with reefal limestones and were incorporated into continental margin melanges either by submarine sliding from the downgoing oceanic plate or by shallow-level offscraping along decollement surfaces during the subduction of oceanic plates. Older, uplifted parts of the fossil accretionary prisms on the continent side further inward from the trench where the deeper levels of accreted material are exposed include larger amounts of basaltic blocks. This observation suggests that significant amount of underplating might have occurred in the deeper levels of oceanic crust along decollement zones at structurally lower depths. The metamorphic belts (e.g.Sambagawa, Chichibu, Shimanto etc.) have commonly alkaline rocks or plateau-type E-MORB basalts without any trace of N-MORB rocks with rare special exceptions. Besides these ordinary accretionary prism examples formed by a simple plate subduction system, another type of accretion resulting from island arc or ridge collision is observed to have occurred in

  5. Larger foraminifer biostratigraphy of PEACE boreholes, Enewetak Atoll, Western Pacific Ocean. Geologic and geophysical investigations of Enewetak Atoll, Republic of the Marshall Islands. Professional paper

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, T.G.; Margerum, R.

    1991-01-01

    Larger foraminiferal assemblages, including Lepidocyclina orientalis, Miogypsina thecideaeformis, Miogypsinoides dehaartii, etc., and a smaller foraminifer, Austrotrillina striata, are used to correlate upper Oligocene and lower Miocene strata in the Pacific Atoll Exploration Program (PEACE) boreholes at Enewetak Atoll, Republic of the Marshall Islands, western Pacific Ocean, with the Te and Tf zones of the previously established Tertiary Far East Letter Zonation. Correlation using these two benthic groups is critical because calcareous nannofossils and planktic foraminifers are absent in the lower Miocene strata. Biostratigraphic data from these boreholes delineate a thick (greater than 700 feet) sequence of upper Oligocene and lower Miocene strata corresponding to lower and upper Te zone. These strata document a major period of carbonate accumulation at Enewetak during the Late Oligocene and early Miocene (26 to 18 million years ago).

  6. Geochemistry of the ophiolite and oceanic island basalt in the Kangxian-Pipasi-Nanping tectonic mélange zone, South Qinling and their tectonic significance

    Institute of Scientific and Technical Information of China (English)

    LAI Shaocong; ZHANG Guowei; PEI Xianzhi; YANG Haifeng

    2004-01-01

    Detailed studies indicate that Kangxian-Pipasi-Nanping tectonic zone is a complicated mélange zone which includes many tectonic slabs of different origins. Ophiolite (MORB-type basalt), oceanic island tholeiite and alkaline basalt have been identified. Moreover, this tectonic mélange zone is eastward connected with the Mianlüe suture zone. The deformation characteristics, consisting components and volcanic rock geochemical features for the Kangxian-Pipasi-Nanping tectonic mélange zone are much similar to those of the Mianlüe suture zone and Deerni ophiolite. Therefore, the Kangxian-Pipasi-Nanping tectonic mélange zone should be the westward extension part of the Mianlüe suture zone. It indicates that the Mianlüe suture zone had extended to the Nanping area.

  7. pH homeostasis during coral calcification in a free ocean CO2 enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef.

    Science.gov (United States)

    Georgiou, Lucy; Falter, James; Trotter, Julie; Kline, David I; Holcomb, Michael; Dove, Sophie G; Hoegh-Guldberg, Ove; McCulloch, Malcolm

    2015-10-27

    Geochemical analyses (δ(11)B and Sr/Ca) are reported for the coral Porites cylindrica grown within a free ocean carbon enrichment (FOCE) experiment, conducted on the Heron Island reef flat (Great Barrier Reef) for a 6-mo period from June to early December 2010. The FOCE experiment was designed to simulate the effects of CO2-driven acidification predicted to occur by the end of this century (scenario RCP4.5) while simultaneously maintaining the exposure of corals to natural variations in their environment under in situ conditions. Analyses of skeletal growth (measured from extension rates and skeletal density) showed no systematic differences between low-pH FOCE treatments (ΔpH = ∼-0.05 to -0.25 units below ambient) and present day controls (ΔpH = 0) for calcification rates or the pH of the calcifying fluid (pHcf); the latter was derived from boron isotopic compositions (δ(11)B) of the coral skeleton. Furthermore, individual nubbins exhibited near constant δ(11)B compositions along their primary apical growth axes (±0.02 pHcf units) regardless of the season or treatment. Thus, under the highly dynamic conditions of the Heron Island reef flat, P. cylindrica up-regulated the pH of its calcifying fluid (pHcf ∼8.4-8.6), with each nubbin having near-constant pHcf values independent of the large natural seasonal fluctuations of the reef flat waters (pH ∼7.7 to ∼8.3) or the superimposed FOCE treatments. This newly discovered phenomenon of pH homeostasis during calcification indicates that coral living in highly dynamic environments exert strong physiological controls on the carbonate chemistry of their calcifying fluid, implying a high degree of resilience to ocean acidification within the investigated ranges.

  8. Spatial and temporal variation of macro-, meso- and microplastic abundance on a remote coral island of the Maldives, Indian Ocean.

    Science.gov (United States)

    Imhof, Hannes K; Sigl, Robert; Brauer, Emilia; Feyl, Sabine; Giesemann, Philipp; Klink, Saskia; Leupolz, Kathrin; Löder, Martin G J; Löschel, Lena A; Missun, Jan; Muszynski, Sarah; Ramsperger, Anja F R M; Schrank, Isabella; Speck, Susan; Steibl, Sebastian; Trotter, Benjamin; Winter, Isabel; Laforsch, Christian

    2017-03-15

    Plastic debris is ubiquitous in the marine environment and the world's shores represent a major sink. However, knowledge about plastic abundance in remote areas is scarce. Therefore, plastic abundance was investigated on a small island of the Maldives. Plastic debris (>1mm) was sampled once in natural long-term accumulation zones at the north shore and at the high tide drift line of the south shore on seven consecutive days to quantify daily plastic accumulation. Reliable identification of plastic debris was ensured by FTIR spectroscopy. Despite the remoteness of the island a considerable amount of plastic debris was present. At both sites a high variability in plastic abundance on a spatial and temporal scale was observed, which may be best explained by environmental factors. In addition, our results show that snapshot sampling may deliver biased results and indicate that future monitoring programs should consider spatial and temporal variation of plastic deposition.

  9. Failure to demonstrate experimental vertical transmission of the epidemic strain of Chikungunya virus in Aedes albopictus from La Réunion Island, Indian Ocean

    Directory of Open Access Journals (Sweden)

    Marie Vazeille

    2009-07-01

    Full Text Available Aedes albopictus was responsible for transmission in the first outbreak of chikungunya (CHIK on La Réunion Island, Indian Ocean, in 2005-2006. The magnitude of the outbreak on this island, which had been free of arboviral diseases for over 30 years, as well as the efficiency of Ae. albopictus as the main vector, raises questions about the maintenance of the CHIK virus (CHIKV through vertical transmission mechanisms. Few specimens collected from the field as larvae were found to be infected. In this study, Ae. albopictus originating from La Réunion were orally infected with a blood-meal containing 10(8 pfu/mL of the CHIKV epidemic strain (CHIKV 06.21. Eggs from the first and second gonotrophic cycles were collected and raised to the adult stage. The infectious status of the progeny was checked (i by immunofluorescence on head squashes of individual mosquitoes to detect the presence of viral particles or (ii by quantitative RT-PCR on mosquito pools to detect viral RNA. We analysed a total of 1,675 specimens from the first gonotrophic cycle and 1,709 from the second gonotrophic cycle without detecting any viral particles or viral RNA. These laboratory results are compared to field records.

  10. Crustal Evolution of a Paleozoic Intra-oceanic Island-Arc-Back-Arc Basin System Constrained by the Geochemistry and Geochronology of the Yakuno Ophiolite, Southwest Japan

    Directory of Open Access Journals (Sweden)

    Yoshimitsu Suda

    2014-01-01

    Full Text Available The Yakuno ophiolite in southwest Japan is considered to have been obducted by the collision between an intra-oceanic island-arc-back-arc basin (intra-OIA-BAB system and the East Asian continent during the late Paleozoic. New SIMS (SHRIMP zircon U-Pb determinations for amphibolite and metagabbro of BAB origin within the Yakuno ophiolite yield ages of 293.4 ± 9.5 Ma and 288 ± 13 Ma, respectively. These ages are slightly older (however, overlapping within analytical errors than the magmatic age of arc granitoids (ca. 285–282 Ma that intruded into the mafic rocks of BAB origin. Results from geochronological and geochemical data of the Yakuno ophiolite give rise to the following tentative geotectonic model for the Paleozoic intra-OIA-BAB system: the initial stage of BAB rifting (ca. 293–288 Ma formed the BAB crust with island-arc basalt (IAB signatures, which was brought to the OIA setting, and generated the arc granitoids (ca. 285–282 Ma by anatexis of the BAB crust. A later stage of BAB rifting (

  11. Trends and tactics of mouse predation on Tristan Albatross Diomedea dabbenena chicks at Gough Island, South Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Delia Davies

    2015-06-01

    Full Text Available The critically endangered Tristan Albatross Diomedea dabbenena breeds almost exclusively on Gough Island, in the central South Atlantic, where breeding success is much lower than other great albatrosses (Diomedea spp. worldwide. Most breeding failures occur during the chick-rearing stage, when other great albatrosses suffer few failures. This unusual pattern of breeding failure is assumed to be largely due to predation by introduced house mice Mus musculus, but there have been few direct observations of mouse attacks. We closely monitored the fates of 20 chicks in the Gonydale study colony (123 chicks in 2014 using motion-activated cameras to determine the causes of chick mortality. Only 5 of 20 chicks survived to fledge, and of the 15 failures, 14 (93% were due to mouse predation. One mouse-wounded chick was killed by a Southern Giant Petrel Macronectes giganteus; the rest died outright from their wounds within 3.9 ± 1.2 days of the first attack. Despite this high impact, most chicks were attacked by only 1-2 mice at once (maximum 9. The remaining 103 chicks in the study colony were checked less frequently, but the timing of failures was broadly similar to the 20 closely monitored nests, and the presence of mouse wounds on other chicks strongly suggests that mice were responsible for most chick deaths. Breeding success in the Gonydale study colony averages 28% from 2001 to 2014; far lower than the normal range of breeding success of Diomedea species occurring on islands free from introduced predators. Island-wide breeding success fell below 10% for the first time in 2014, making it even more urgent to eradicate mice from Gough Island.

  12. Long-distance island hopping without dispersal stages: transportation across major zoogeographic barriers in a Southern Ocean isopod

    Science.gov (United States)

    Leese, Florian; Agrawal, Shobhit; Held, Christoph

    2010-06-01

    Species integrity is maintained only if recurrent allelic exchange between subpopulations occurs by means of migrating specimens. Predictions of this gene flow on the basis of observed or assumed mobility of marine species have proven to be error-prone. Using one mitochondrial gene and seven microsatellite markers, we studied the genetic structure and gene flow in Septemserolis septemcarinata, a strictly benthic species lacking pelagic larvae and the ability to swim. Suitable shallow-water habitats around three remote islands (South Georgia, Bouvet, and Marion Island) are geographically disjunct, isolated by more than 2,000 km of uninhabitable deep sea (east-west) and also separated by the Polar Front (north-south), which serves as a strong demarcation line in many marine taxa. Although we did find genetic differentiation among the three island populations, our results also revealed that a scenario with recent gene flow explains our data best. A model assuming no gene flow after initial colonization of the islands performs significantly worse. The tests also favor an asymmetric gene flow pattern (west to east ≫ east to west) thus mirroring the directionality of major oceanographic currents in the area. We conclude that rare long-distance dispersal rather than vicariance or human-mediated transport must be responsible for the observed patterns. As a mechanism, we propose passive rafting on floating substrata in the Antarctic Circumpolar Current. The results demonstrate that the effectiveness of a physical barrier is not solely a function of its physical parameters but strongly depends on how organisms interact with their environment.

  13. Foraging of the green sea turtle Chelonia mydas on seagrass beds at Mayotte Island (Indian Ocean), determined by acoustic transmitters

    OpenAIRE

    TAQUET Coralie; Taquet, Marc; T. Dempster; Soria, M.; Ciccione, S.; Roos, David; Dagorn, L.

    2006-01-01

    We studied the foraging rhythms of green sea turtles Chelonia mydas on the seagrass beds of N'Gouja Bay, Mayotte Island (Comoros Archipelago) with acoustic transmitters and moored listening stations. We monitored 8 tagged turtles (4 probable males, 3 probable females and 1 immature), from 70 to 109 cm curved carapace length (CCL), for durations ranging from 5 to 92 d. The turtles exhibited a regular diel pattern: they foraged mainly during the day (on average 87% of seagrass detections were b...

  14. Seroepidemiology, viral isolation, and molecular characterization of human T cell leukemia/lymphoma virus type I from La Réunion Island, Indian Ocean.

    Science.gov (United States)

    Mahieux, R; Gessain, A; Truffert, A; Vitrac, D; Hubert, A; Dandelot, J; Montchamp-Moreau, C; Cnudde, F; Tekaia, F; De Thé, G

    1994-06-01

    Data indicate the presence in the Seychelles Islands of a high level of human T cell leukemia/lymphoma virus type I (HTLV-I) endemicity as well as the presence of tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). We present here the results of an hospital survey performed since 1988 in La Réunion Island, located in the Indian Ocean southeast of the Seychelles archipelago, aimed at evaluating HTLV-I endemicity, detecting HTLV-I-associated diseases, and characterizing viral isolates. Seven individuals were found to have HTLV-I-specific antibodies in their sera. These include 3 of 257 patients from St. Pierre Hospital, 1 of them exhibiting a typical clinical feature of TSP/HAM (the first described case in this region), 1 blood donor of 3900, and 3 relatives. A further nine individuals exhibiting only "gag-encoded proteins" by Western blot (p19 and/or p24 bands) were found negative by polymerase chain reaction using LTR, pol, and tax HTLV-I specific primers. A long-term T cell line, designated Mel.J, exhibiting T cell activation markers (CD4+, CD25+, HLA-DR+), and producing HTLV-I antigens and viral particles, was established from one of the HTLV-I,-seropositive patients. The sequence of a 522-bp fragment corresponding to the carboxy terminus of gp46 and the majority of gp21 were determined for five HTLV-I-seropositive individuals, including the TSP/HAM patient. Alignment and phylogenetic comparison of these five nucleotide sequences with all the 53 other available HTLV-I env sequences demonstrated that the virus from La Réunion Island belongs to the group of the HTLV-I cosmopolitan subtype and is not related to the Melanesian HTLV-I variants.

  15. Tar sand

    Energy Technology Data Exchange (ETDEWEB)

    McLendon, T.R.; Bartke, T.C.

    1990-01-01

    Research on tar sand is briefly discussed. The research program supported by the US Department of Energy (DOE) includes a variety of surface extraction schemes. The University of Utah has process development units (PDU) employing fluidized bed, hot, water-assisted, and fluidized-bed/heat-pipe, coupled combustor technology. Considerable process variable test data have been gathered on these systems: (1) a rotary kiln unit has been built recently; (2) solvent extraction processing is being examined; and (3) an advanced hydrogenation upgrading scheme (hydropyrolysis) has been developed. The University of Arkansas, in collaboration with Diversified Petroleum, Inc., has been working on a fatty acid, solvent extraction process. Oleic acid is the solvent/surfactant. Solvent is recovered by adjusting processing fluid concentrations to separate without expensive operations. Western Research Institute has a PDU-scale scheme called the Recycle Oil Pyrolysis and Extraction (ROPE) process, which combines solvent (hot recycle bitumen) and pyrolytic extraction. 14 refs., 19 figs.

  16. Annual report : 1938-1939 : Sand Lake Migratory Waterfowl Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Sand Lake Migratory Waterfowl Refuge covers the 1939 fiscal year. Wildlife populations, artificial islands, haying, share cropping,...

  17. A new aeromagnetic survey of the North Pole and the Arctic Ocean north of Greenland and Ellesmere Island

    DEFF Research Database (Denmark)

    Matzka, Jürgen; Rasmussen, Thorkild M.; Olesen, Arne Vestergaard

    2010-01-01

    We present a preliminary analysis of more than 50,000 km of aeromagnetic survey lines flown in the Arctic Ocean, acquired in 2009 with an optically pumped scalar magnetometer as part of the airborne geophysical survey ‘LOMGRAV’. From the observations we removed main and magnetospheric fields as g...

  18. It's in the sand

    OpenAIRE

    Mitchell, Clive

    2016-01-01

    Sand is sand isn’t it? Sand gets everywhere but rather than a nuisance it is a valuable, high-purity raw material. Clive Mitchell, Industrial Minerals Specialist at the British Geological Survey (BGS), talks us through what sand is, what it can be used for and how to find it. His exploration of sand takes us from the deserts of Arabia to the damp sand pits of Mansfield!

  19. Microbial and Metabolic Diversity of the Alkaline Hot Springs of Paoha Island: A Late Archean and Proterozoic Ocean Analogue Environment.

    Science.gov (United States)

    Foster, I. S.; Demirel, C.; Hyde, A.; Motamedi, S.; Frantz, C. M.; Stamps, B. W.; Nunn, H. S.; Oremland, R. S.; Rosen, M.; Miller, L. G.; Corsetti, F. A.; Spear, J. R.

    2016-12-01

    Paoha Island formed 450 years ago within Mono Lake, California, as a result of magmatic activity in the underlying Long Valley Caldera. Previous studies of Paoha Island hot springs focused on the presence of novel organisms adapted to high levels of arsenic (114-138 µM). However, the microbial community structure, relationship with Mono Lake, and preservation potential of these communities remains largely unexplored. Here, we present water chemistry, 16S and 18S rRNA gene sequences, and metagenomic data for spring water and biofilms sampled on a recently exposed mudflat along the shoreline of Paoha Island. Spring waters were hypoxic, alkaline, and saline, had variable temperature (39-70 °C near spring sources) and high concentrations of arsenic, sulfide and reduced organic compounds. Thermodynamic modeling based on spring water chemistry indicated that sulfide and methane oxidation were the most energetically favorable respiratory metabolisms. 16S rRNA gene sequencing revealed distinct communities in different biofilms: red biofilms were dominated by arsenite-oxidizing phototrophs within the Ectothiorhodospiraceae, while OTUs most closely related to the cyanobacterial genus Arthrospira were present in green biofilms, as well as a large proportion of sequences assigned to sulfur-oxidizing bacteria. Metagenomic analysis identified genes related to arsenic resistance, arsenic oxidation/reduction, sulfur oxidation and photosynthesis. Eukaryotic rRNA gene sequencing analyses revealed few detectable taxa in spring biofilms and waters compared to Mono Lake; springs receiving splash from the lake were dominated by the alga Picocystis. The co-occurrence of hypoxia, high pH, and close proximity of anoxygenic and oxygenic phototrophic mats makes this site a potential Archean/Proterozoic analogue environment, but suggests that similar environments if preserved in the rock record, may not preserve evidence for community dynamics or the existence of photosynthetic metabolisms.

  20. Metals and radionuclides in birds and eggs from Amchitka and Kiska Islands in the Bering Sea/Pacific Ocean ecosystem.

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2007-04-01

    Metals and radionuclide levels in marine birds of the Aleutians are of interest because they are part of subsistence diets of the Aleut people, and can also serve as indicators of marine pollution. We examined geographic and species-specific variations in concentrations of radionuclides in birds and their eggs from Amchitka, the site of underground nuclear tests from 1965 to 1971, and Kiska Islands (a reference site) in the Aleutians, and the levels of lead, mercury and cadmium in eggs. In 2004 we collected common eiders (Somateria mollissima), tufted puffins (Fratercula cirrhata), pigeon guillemot (Cepphus columba) and glaucous-winged gulls (Larus glaucescens) from Amchitka and Kiska, and eggs from eiders and gulls from the two island. We also collected one runt bald eagle (Haliaeetus leucocephalus) chick from both Amchitka and Kiska Islands. For most species, the levels of radionuclide isotopes were below the minimum detectable activity levels (MDA). Out of 74 cesium-137 analyses, only one composite (gulls) was above the MDA, and out of 14 composites tested for plutonium (Pu-239, 240), only one exceeded the MDA (a guillemots). Three composites out of 14 tested had detectable uranium-238. In all cases, the levels were low and close to the MDAs, and were below those reported for other seabirds. There were significant interspecific differences in metal levels in eggs: gulls had significantly higher levels of cadmium and mercury than the eiders, and eiders had higher levels of lead than gulls. There were few significant differences as a function of island, but eiders had significantly higher levels of cadmium in eggs from Kiska, and gulls had significantly higher levels of mercury on Kiska. The levels of cadmium and mercury in eggs of eiders and gulls from this study were above the median for cadmium and mercury from studies in the literature. The levels of mercury in eggs are within the range known to affect avian predators, but seabirds seem less vulnerable to

  1. Deep-sea palaeoceanography of the Maldives Islands (ODP Hole 716A), equatorial Indian Ocean during MIS 12–6

    Indian Academy of Sciences (India)

    S Sarkar; A K Gupta

    2009-11-01

    Deep-sea benthic foraminifera, planktic foraminifer Globigerina bulloides and pteropods have been quantitatively analysed in 451 samples from Ocean Drilling Program (ODP) Hole 716A, to understand both surface and deep-sea palaeoceanographic changes in the equatorial Indian Ocean basin during the late Quaternary (∼444–151 Kyrs). Benthic foraminifera were analysed from > 125 m size fraction whereas Globigerina bulloides and pteropods were analysed from > 150 m size fraction. Factor analysis of most dominant benthic foraminiferal species over the studied time span made it possible to identify three biofacies characterizing distinct deep-sea environmental settings at Hole 716A. The environmental interpretation of each species is based on the ecology of recent deep-sea benthic foraminifera. The faunal record indicates fluctuating deep-sea conditions including changes in surface productivity, organic food supply and deep-sea oxygenation linked to changing wind intensities. These changes are pronounced on glacial-interglacial time scales driven by summer monsoon winds.

  2. Status Of Coral Reefs In The South West Indian Ocean Island Node: Comoros, Madagascar, Mauritius, Reunion And Seychelles

    OpenAIRE

    Bijoux, J.; Moyne-Picard, M. (collab.); Paupiah, N.; Ahamada, S.; Meunier, S.; Maharavo, J.; Bigot, L.

    2002-01-01

    A regional monitoring network of the GCRMN was formed just after the major coral bleaching event in 1998. The goal was to assist the Comoros, Madagascar, Mauritius, Reunion and Seychelles manage their reef resources within the Regional Environment Programme of the Indian Ocean Commission. The Node is now being financed for 3 years by the Global Environment Facility (GEF and World Bank) and the European Union to continue coral reef monitoring to strengthen the capacity of nation...

  3. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  4. EMI – young HIMU rock association at the Cape Verde Islands revisited: on the role of oceanic carbonatites

    DEFF Research Database (Denmark)

    Holm, Paul Martin; Kokfelt, Thomas Find; Dyhr, Charlotte Thorup

    .7031. Incompatible trace element ratios such as Ba/Nb, Ba/La, Th/Rb, La/Nb, La/Th of Fogo-EM1 are comparable to other EM1-type OIB, whereas SA young HIMU-rocks overlap with classical HIMU. The SN end-member has Ba/Nb=6-9, Ba/La=8-14, and La/Th=9-11 in the range of EM1 and HIMU, but has relatively lower Rb than even...... HIMU. Carbonatites are widespread throughout Cape Verde Islands but volumetrically minor and are low in Ti, K, and Rb. In several silicate rocks from all three islands low Ti/Eu is evidence for a carbonatite component and is accompanied by LREE enrichment, and relatively low K and Rb. Other rocks have...... and the rocks have mantle Ti/Eu. There is a strong correlation of Rb/La and Rb/Sr demonstrating that fluids are unlikely agents to explan this variation. Phlogopite control is also excluded due to decoupling of Rb and K from Ba. A possible explanation for the low K and Rb is dehydration of the mantle source...

  5. Volcanology and eruptive styles of Barren Island: an active mafic stratovolcano in the Andaman Sea, NE Indian Ocean

    Science.gov (United States)

    Sheth, Hetu C.; Ray, Jyotiranjan S.; Bhutani, Rajneesh; Kumar, Alok; Smitha, R. S.

    2009-11-01

    Barren Island (India) is a relatively little studied, little known active volcano in the Andaman Sea, and the northernmost active volcano of the great Indonesian arc. The volcano is built of prehistoric (possibly late Pleistocene) lava flows (dominantly basalt and basaltic andesite, with minor andesite) intercalated with volcaniclastic deposits (tuff breccias, and ash beds deposited by pyroclastic falls and surges), which are exposed along a roughly circular caldera wall. There are indications of a complete phreatomagmatic tephra ring around the exposed base of the volcano. A polygenetic cinder cone has existed at the centre of the caldera and produced basalt-basaltic andesite aa and blocky aa lava flows, as well as tephra, during historic eruptions (1787-1832) and three recent eruptions (1991, 1994-95, 2005-06). The recent aa flows include a toothpaste aa flow, with tilted and overturned crustal slabs carried atop an aa core, as well as locally developed tumuli-like elliptical uplifts having corrugated crusts. Based on various evidence we infer that it belongs to either the 1991 or the 1994-95 eruptions. The volcano has recently (2008) begun yet another eruption, so far only of tephra. We make significantly different interpretations of several features of the volcano than previous workers. This study of the volcanology and eruptive styles of the Barren Island volcano lays the ground for detailed geochemical-isotopic and petrogenetic work, and provides clues to what the volcano can be expected to do in the future.

  6. Diet analysis by next-generation sequencing indicates the frequent consumption of introduced plants by the critically endangered red-headed wood pigeon (Columba janthina nitens) in oceanic island habitats.

    Science.gov (United States)

    Ando, Haruko; Setsuko, Suzuki; Horikoshi, Kazuo; Suzuki, Hajime; Umehara, Shoko; Inoue-Murayama, Miho; Isagi, Yuji

    2013-10-01

    Oceanic island ecosystems are vulnerable to the introduction of alien species, and they provide a habitat for many endangered species. Knowing the diet of an endangered animal is important for appropriate nature restoration efforts on oceanic islands because introduced species may be a major component of the diets of some endangered species. DNA barcoding techniques together with next-generation sequencing may provide more detailed information on animal diets than other traditional methods. We performed a diet analysis using 48 fecal samples from the critically endangered red-headed wood pigeon that is endemic to the Ogasawara Islands based on chloroplast trnL P6 loop sequences. The frequency of each detected plant taxa was compared with a microhistological analysis of the same sample set. The DNA barcoding approach detected a much larger number of plants than the microhistological analysis. Plants that were difficult to identify by microhistological analysis after being digested in the pigeon stomachs were frequently identified only by DNA barcoding. The results of the barcoding analysis indicated the frequent consumption of introduced species, in addition to several native species, by the red-headed wood pigeon. The rapid eradication of specific introduced species may reduce the food resources available to this endangered bird; thus, balancing eradication efforts with the restoration of native food plants should be considered. Although some technical problems still exist, the trnL approach to next-generation sequencing may contribute to a better understanding of oceanic island ecosystems and their conservation.

  7. 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

  8. Industrial sand and gravel

    Science.gov (United States)

    Dolley, T.P.

    2013-01-01

    Domestic production of industrial sand and gravel in 2012 was about 49.5 Mt (55 million st), increasing 13 percent compared with that of 2011. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

  9. Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean

    Directory of Open Access Journals (Sweden)

    C. Venchiarutti

    2011-11-01

    Full Text Available Dissolved and particulate excess 230Th and 231Pa concentrations (noted 230Thxs and 231Paxs respectively and 231Paxs/230Thxs activity ratios were investigated on and out of the Kerguelen plateau (Southern Ocean in the framework of the Kerguelen Ocean and Plateau compared Study project in order to better understand the influence of particle flux and particle chemistry and advection on the scavenging of 231Pa.

    In the wake of Kerguelen, particulate 231Paxs is relatively abundant compared to its content in the dissolved phase. This, together with the low fractionation observed between 230Th and 231Pa (FTh/Pa ranging from 0.06 ± 0.01 to 1.6 ± 0.2 reflects the domination of the biogenic silica in the particle pool.

    Along the eastern escarpment of the Kerguelen plateau, the strong 231Paxs horizontal gradient in the deep waters highlights the intense removal of 231Pa at depth, as already observed for 230Thxs. This local boundary scavenging was attributed to re-suspension of opal-rich particles by nepheloid layers, resulting in fractionation factors FTh/Pa ≤ 1 along the Kerguelen plateau slope. Therefore, both the composition (biogenic opal and the flux (intense along the margin of particles control the scavenging of the two radionuclides in the Kerguelen wake.

    The modelling of 231Pa distribution with an advection-scavenging model demonstrates that lateral advection of open ocean water on the Kerguelen plateau could supply most of the 231Pa, which is then efficiently scavenged on the highly productive plateau, as previously proposed for 230Thxs. It stresses that lateral advection can play a significant role in the overall

  10. Degradation of Cymodocea nodosa (Ucria) Ascherson meadow at Las Canteras Beach (Gran Canaria, Canary Islands, Atlantic Ocean)

    Institute of Scientific and Technical Information of China (English)

    Milena Polifrone; Miquel Rosell-Fieschi

    2014-01-01

    Objective: To monitor the distribution of Cymodocea nodosa (Ucria) Ascherson in Las Canteras Beach (Las Palmas de Gran Canaria, Spain), comparing the status in 2005 with the distribution observed in 1985 and 1995. Methods: Field observations by selfcontained underwater breathing apparatus diving records and cartographic report.Results:rocks, which sheltered it from the strong north-east winds and swells. Since 1985 a gradual reduction of its extent has been observed and more than 80% of the original canopy disappeared in twenty years time, mostly due to the anthropogenic impact and modification of the sedimentary dynamics of the beach.Conclusions:Conclusions: The degradation of this seagrass meadow determinates the loss of the only meadow in the north of the island of Gran Canaria and the absence of a management plan for its conservation.

  11. Possible Late Pleistocene volcanic activity on Nightingale Island, South Atlantic Ocean, based on geoelectrical resistivity measurements, sediment corings and 14C dating

    DEFF Research Database (Denmark)

    Bjørk, Anders Anker; Björck, Svante; Cronholm, Anders

    2011-01-01

    Tristan da Cunha is a volcanic island group situated in the central South Atlantic. The oldest of these islands, Nightingale Island, has an age of about 18Ma. In the interior of the island, there are several wetlands situated in topographic depressions. The ages of these basins have been unknown,...

  12. Towards a more holistic research approach to plant conservation: the case of rare plants on oceanic islands.

    Science.gov (United States)

    Silva, Luís; Dias, Elisabete Furtado; Sardos, Julie; Azevedo, Eduardo Brito; Schaefer, Hanno; Moura, Mónica

    2015-06-11

    Research dedicated to rare endemic plants is usually focused on one given aspect. However, holistic studies, addressing several key issues, might be more useful, supporting management programmes while unravelling basic knowledge about ecological and population-level processes. A more comprehensive approach to research is proposed, encompassing: phylogenetics/systematics, pollination biology and seed dispersal, propagation, population genetics, species distribution models (SDMs), threats and monitoring. We present a holistic study dedicated to Veronica dabneyi Hochst. ex Seub., an endangered chamaephyte endemic to the Azores. Veronica dabneyi was mainly found associated with other endemic taxa; however, invasive plants were also present and together with introduced cattle, goats and rabbits are a major threat. Most populations grow at somewhat rocky and steep locations that appeared to work as refuges. Seed set in the wild was generally high and recruitment of young plants from seed seemed to be frequent. In the laboratory, it was possible to germinate and fully develop V. dabneyi seedlings, which were planted at their site of origin. No dormancy was detected and time for 50 % germination was affected by incubation temperature. Eight new microsatellite markers were applied to 72 individuals from 7 sites. A considerable degree of admixture was found between samples from the two islands Flores and Corvo, with 98 % of the genetic variability allocated within populations. Levels of heterozygosity were high and no evidence of inbreeding was found. Species distribution models based on climatic and topographic variables allowed the estimation of the potential distribution of V. dabneyi on Flores and Corvo using ecological niche factor analysis and Maxent. The inclusion of land-use variables only slightly increased the information explained by the models. Projection of the expected habitat in Faial largely coincided with the only historic record of V. dabneyi on that island

  13. Tsunami hazard assessment in La Reunion and Mayotte Islands in the Indian Ocean : detailed modeling of tsunami impacts for the PREPARTOI project

    Science.gov (United States)

    Quentel, E.; Loevenbruck, A.; Sahal, A.; Lavigne, F.

    2011-12-01

    Significant tsunamis have often affected the southwest Indian Ocean. The scientific project PREPARTOI (Prévention et REcherche pour l'Atténuation du Risque Tsunami dans l'Océan Indien), partly founded by the MAIF foundation, aims at assessing the tsunami risk on both french islands of this region, La Réunion and Mayotte. Further purpose of this project is the detailed hazard and vulnerability study for specific places of these islands, selected according to their environmental and human issues and observed impacts of past tsunamis. Tsunami hazard in this region, recently highlighted by major events in the southwest Indian Ocean, has never been thoroughly evaluated. Our study, within the PREPARTOI project, contributes to fill in this lack. It aims at examining transoceanic tsunami hazard related to earthquakes by modeling the scenarios of major historical events. We consider earthquakes with magnitude greater than Mw 7.7 located on the Sumatra (1833, 2004, 2010), Java (2006) and Makran (1945) subduction zones. First, our simulations allow us to compare the tsunami impact at regional scale according to the seismic sources; we thus identify earthquakes locations which most affect the islands and describe the impact distribution along their coastline. In general, we note that, for the same magnitude, events coming from the southern part of Sumatra subduction zone induce a larger impact than the north events. The studied tsunamis initiated along the Java and Makran subduction zones have limited effects on both French islands. Then, detailed models for the selected sites are performed based on high resolution bathymetric and topographic data; they provide estimations of the water currents, the water heights and the potential inundations. When available, field measurements and maregraphic records allow testing our models. Arrival time, amplitude of the first wave and impact on the tide gauge time series are well reproduced. Models are consistent with the observations

  14. Recommendations for a Barrier Island Breach Management Plan for Fire Island National Seashore, including the Otis Pike High Dune Wilderness Area, Long Island, New York

    Science.gov (United States)

    Williams, S. Jeffress; Foley, Mary K.

    2007-01-01

    ) policy stipulates that natural coastal processes be maintained to the greatest extent possible and not be impeded so as to conserve landforms, habitats and natural ecosystem resources that reply on the landforms and processes for long-term sustainability of the national park. Storms and associated processes such as waves, tides, currents and relative sea-level change are critical elements for the formation and evolution of these barrier islands, sand dunes, back-barrier sand flats and lagoons and vegetated wetlands. Processes such as wave run-up, overwash and barrier beaching, which occur during elevated storm surge are all necessary processes in enabling the efficient transfer of sediments, nutrients and marine water from the Atlantic Ocean across barriers and into Great South Bay. A large body of scientific data and information published over the past 50 years shows that such transfers of sediment and water from the ocean to the bays are essential for the long-term maintenance of the barrier island and back-bay systems and their biologically diverse habitats an d ecosystems. Current relative sea-level rise (~12 in/century) is chronic and pervasive in driving Long Island coastal change and with the likelihood of accelerating sea level rise in the near future, coastal hazards such as erosion, inundation, and storm surge flooding will increase, with corresponding increased risk to life and property on both Fire Island and on the mainland. In addition, the cumulative effects over the past century and more, both direct and indirect, of human impacts on the Long Island coast have altered the barrier beach and dunes and sediment transport processes. These impacts have likely increased the potential for breaching and increased risk to life and property on the coast and the mainland. Examples of direct impacts are: the stone jetties at Moriches, Shinnecock, and Fire Island tidal inlets and groin field structures at Westhampton that alter littoral processes, armoring and erosion

  15. Arctic ice islands

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

    1988-01-01

    The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

  16. Eruptive response of oceanic islands to giant landslides: New insights from the geomorphologic evolution of the Teide-Pico Viejo volcanic complex (Tenerife, Canary)

    Science.gov (United States)

    Boulesteix, Thomas; Hildenbrand, Anthony; Gillot, Pierre-Yves; Soler, Vicente

    2012-02-01

    Large sector collapses are a major component of oceanic islands evolution. Here we show that voluminous events such as the Icod landslide on Tenerife (Canary Islands) cause dramatic changes on the magma feeding system and control the subsequent volcanic and geomorphologic evolution of the eruptive complex over a period of more than 150 kyr. Instantaneous unloading by the Icod landslide is marked by the development of a large phonolitic explosive eruption dated at 175 ± 3 ka and interpreted as reflecting the immediate emptying of a shallow pre-existing magma chamber. Geochronological, geomorphological and geochemical analyses, carried out on the post-landslide volcanic succession sampled in a 4.4 km-long underground water-recovery gallery, provide further evidence for an enhanced extrusion of primitive lavas starting in the 10 kyr time interval following the failure. Rapid construction (scar at high eruptive rates (up to 8 km 3 kyr -1) increased the lithostatic pressure which then favored the intermittent storage of basic magma under the edifice. This resulted in more episodic construction evidenced by a significant decrease in output rates and the increasing occurrence of lavas with intermediate composition from 117 ± 7 to 52 ± 7 ka. An apparent volcanic gap is observed between 52 ± 7 and 18 ± 1 ka, after which highly differentiated lavas have been dominantly erupted. We propose that part of the gap can be explained by the individualization of a shallow magma reservoir a few kilometers below the base of the Teide volcano. During recent periods, vertical and lateral extrusions of trachytic and phonolitic viscous bodies from this storage area contributed to increase the slope of the main edifice up to 35°, overall favoring its present-day instability.

  17. Coastal erosion hazard and vulnerability using sig tools. Comparison between "La Barra town, Buenaventura, (Pacific Ocean of Colombia) and Providence - Santa Catalina islands (Colombian Caribbean Sea)

    Science.gov (United States)

    Coca-Domínguez, Oswaldo; Ricaurte-Villota, Constanza; Morales-Giraldo, David; Rangel-Buitrago, Nelson

    2014-05-01

    Analysis of hazards and vulnerability associated to coastal erosion along coastlines is a first issue in order to establish plans for adaptation to climate change in coastal areas. La Barra Town, Buenaventura (Pacific ocean of Colombia) and Providence - Santa Catalina Islands (Colombian Caribbean) were selected to develop a detailed analysis of coastal erosion hazard and vulnerability from different perspectives: i) physical (hazard) , ii) social , iii) conservation approach and iv) cultural heritage (Raizal). The analysis was made by a semi quantitative approximation method, applying variables associated with the intrinsic coastal zone properties (i.e. type of beach, exposure of the coast to waves, etc.). Coastal erosion data and associated variables as well land use; conservation and heritage data were used to carry out a further detailed analysis of the human - structural vulnerability and exposure to hazards. The data shows erosion rates close to -17 m yr-1 in La Barra Town (highlighting their critical condition and urgent relocation process), while in some sectors of Providence Island, such as Old Town, erosion rate was -5 m yr-1. The observed erosion process affects directly the land use and the local and regional economy. The differences between indexes and the structural and physical vulnerability as well the use of methodological variables are presented in the context of each region. In this work, all the information was worked using a GIS environment since this allows editing and updating the information continuously. The application of this methodology generates useful information in order to promote risk management as well prevention, mitigation and reduction plans. In both areas the adaptation must be a priority strategy to be considered, including relocation alternatives and sustainable protection with the support of studies of uses and future outlooks in the coast. The methodology is framed into the use of GIS tools and it highlights their benefits

  18. Increases in soil water content after the mortality of non-native trees in oceanic island forest ecosystems are due to reduced water loss during dry periods.

    Science.gov (United States)

    Hata, Kenji; Kawakami, Kazuto; Kachi, Naoki

    2016-03-01

    The control of dominant, non-native trees can alter the water balance of soils in forest ecosystems via hydrological processes, which results in changes in soil water environments. To test this idea, we evaluated the effects of the mortality of an invasive tree, Casuarina equisetifolia Forst., on the water content of surface soils on the Ogasawara Islands, subtropical islands in the northwestern Pacific Ocean, using a manipulative herbicide experiment. Temporal changes in volumetric water content of surface soils at 6 cm depth at sites where all trees of C. equisetifolia were killed by herbicide were compared with those of adjacent control sites before and after their mortality with consideration of the amount of precipitation. In addition, the rate of decrease in the soil water content during dry periods and the rate of increase in the soil water content during rainfall periods were compared between herbicide and control sites. Soil water content at sites treated with herbicide was significantly higher after treatment than soil water content at control sites during the same period. Differences between initial and minimum values of soil water content at the herbicide sites during the drying events were significantly lower than the corresponding differences in the control quadrats. During rainfall periods, both initial and maximum values of soil water contents in the herbicided quadrats were higher, and differences between the maximum and initial values did not differ between the herbicided and control quadrats. Our results indicated that the mortality of non-native trees from forest ecosystems increased water content of surface soils, due primarily to a slower rate of decrease in soil water content during dry periods.

  19. The nephelinitic-phonolitic volcanism of the Trindade Island (South Atlantic Ocean): Review of the stratigraphy, and inferences on the volcanic styles and sources of nephelinites

    Science.gov (United States)

    Pires, Gustavo Luiz Campos; Bongiolo, Everton Marques

    2016-12-01

    Trindade Island is located in the South Atlantic Ocean, 1170 km from the Brazilian coast, and represents the eastern end of the E-W Vitória-Trindade Chain. It shows the youngest plume-induced (ca. 3.7 to 2.4 Ma) and the Desejado (DF, ∼2.4 to 1.5 Ma), Morro Vermelho (MV, processes within the nephelinite-phonolite volcanism. Also, available geochemical databases were used to improve the stratigraphic correlation between nephelinites from different units and to characterize their mantle sources. The nephelinitic volcanism may represent Strombolian and Hawaiian-type activity of low viscosity and volatile-rich lavas interlayered with pyroclastic successions (fall-out deposits). Phonolitic deposits record explosive Vulcanian-style episodes of volatile-rich and higher-viscosity lavas interlayered with pyroclastic deposits (mostly pyroclastic flows). Geochemical data allowed the individualization of nephelinites as follows: (1) MV olivine-rich nephelinites and all olivine-free varieties are low K2O/Na2O, K2O/TiO2 and intermediate CaO/Al2O3 that may be derived from N-MORB and HIMU mantle components; (2) the VF olivine-rich nephelinites have high K2O/Na2O, K2O/TiO2 and CaO/Al2O3 that indicates both EM and HIMU mantle sources and; (3) the PF olivine-rich nephelinites show high K2O/TiO2 similar to those from VF, and intermediate CaO/Al2O3 as nephelinites from MV rocks, suggesting a mixed source with EM + HIMU > N-MORB components. We suggest that the HIMU and EM mantle types resulted from metasomatic episode(s) in the peridotitic mantle beneath the Trindade Island during the Brasiliano Orogeny and later, as previously pointed out by Marques et al. (1999). Thus, the major HIMU component would relate to recycled oceanic crust or lithospheric mantle (mostly CO2-eclogites) whereas the less important EM component to recycled marine or continental sediments.

  20. A wind tunnel simulation of the dynamic processes involved in sand dune formation on the western coast of Hainan Island%海南岛西海岸沙丘形成动力过程的风洞模拟试验

    Institute of Scientific and Technical Information of China (English)

    李森; 刘贤万; 李会川; 郑影华; 魏兴琥

    2007-01-01

    The western coast of Hainan Island exhibits a savanna landscape. Many types of sand dunes, including transverse dune ridges, longitudinal dune ridges, elliptical dunes, coppice dunes, and climbing dunes, are widely distributed in the coastal zone. In winter, high-frequency and high-energy NE winds (dominant winds) are prevalent, with a resultant drift direction (RDD) of S35.6°W. In spring, low-frequency and low-energy SW secondary winds prevail, with a RDD of N25.1°E. Wind tunnel simulations revealed that the airflow over the dune surface is the main factor controlling the erosion and deposition patterns of dune surfaces and the morphological development of dunes. In the region's bidirectional wind environment, with two seasonally distinct energy levels, the airflow over the surface of elliptical dunes, barchan dunes, and transverse dune ridges will exhibit a transverse pattern, whereas the airflow over longitudinal dunes ridges exhibits a lateral pattern and that over climbing dunes exhibits a climbing-circumfluent pattern. These patterns represent different dynamic processes. The coastal dunes on the western coast of Hainan Island are influenced by factors such as onshore winds, sand sources, coastal slopes, rivers, and forest shelter belts. The source of the sand that supplements these dunes particularly influences the development pattern: when there is more sand, the pattern shows positive equilibrium deposition between dune ridges and dunes; otherwise, it shows negative equilibrium deposition. The presence or absence of forest shelter belts also influences deposition and dune development patterns and transformation of dune forms. Coastal dunes and inland desert dunes experience similar dynamic processes, but the former have more diversified shapes and more complex formation mechanisms.

  1. Assessing temporal couplings in social-ecological island systems: historical deforestation and soil loss on Mauritius (Indian Ocean

    Directory of Open Access Journals (Sweden)

    S.J. Norder

    2017-03-01

    Full Text Available Temporal couplings, such as historical interactions between deforestation and soil loss, are responsible for the current state of a wide range of ecosystem services of the social-ecological system on Mauritius. Islands are suitable study sites for understanding temporal couplings and telecouplings because of their: (1 clearly defined physical boundaries, (2 finite local resources, and (3 relatively short human history. Six well-documented historical deforestation maps, starting from the first colonization of Mauritius in 1638, were used as input parameters to model two scenarios of cumulative soil loss, with and without deforestation, using the revised universal soil loss equation in a geographic information system. The scenarios show that historical deforestation since 1638 has resulted in a cumulative soil loss that drastically exceeds soil loss under a natural baseline scenario without deforestation. The adopted method illustrates to what extent the current state of the soil of a social-ecological system is negatively affected by past human-environment interactions. We suggest that potential negative impacts on insular societies are mitigated by telecouplings such as food, fuel, and fertilizer imports.

  2. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...

  3. A Distal Record of Large Hawaiian Submarine Landslides: the Lithology of Sediments Obtained From the Deep-sea Floor Adjacent to the Hawaiian Islands, KR01-K12 Cruise.

    Science.gov (United States)

    Kanamatsu, T.; Naka, J.; Kubo, Y.; Champion, D.; Coombs, M.; Moore, J. G.; Sugiyama, K.; Muraki, H.; Ishimori, M.

    2001-12-01

    To understand the timing and emplacement processes of giant Hawaiian submarine landslide, a series of piston coring was performed in the adjacent area of Hawaii islands by R/V KAIREI, JAMSTEC in the summer of 2001. Long-distance volcaniclastic sediment transport generated by Hawaiian submarine landslides has been suggested by several previous studies (e.g. Garcia and Hull, 1994). Stratigraphical, sedimentological, and geochemical studies on the cores obtained by systematic sampling will make to understand for origins and ages of volcaniclastics emplacement to the ocean-floor. Nine cores were collected from the north of Oahu, the southwest and south of Hawaii Island, the south of Oahu. The major lithology is brown pelagic clay with abundant volcanic sand layers. Off Hawaiian Arch of the north of Oahu, pelagic clay with distinct 195cm-thick volcanic sand layer was recovered. The thick sand should be related to Nuuanu landslide, which debris avalanches were derived from Oahu Island. In the north of Haleakala rift, the alternation of brown colored clay and volcanic sand layer were obtained. Haleakala rift and Kohala slump are possible origins for these frequent occurrences of volcanic sand. In the south of Hawaii Island, we recovered alternations of volcanic sand and pelagic clay. The previous study suggested that volcaniclastic material in this area were derived from the Kilauea and older volcanoes of Hawaii Island. The obtained cores will provide stratigraphic information for volcanic history of Hawaii Island. The lower sequence below the alternation consists of radiolarian ooze, suggest the age of Eocene by on-board inspection. Two piston cores were obtained in the front of Waianae Landslide. The lithology of cores shows that the much volcaniclastics are interbeded in the upper sequence, and the massive clay in the lower.

  4. Oceanographic data and ROV dive-related multimedia and information collected during the EX1606 (CAPSTONE Wake Island Unit PRIMNM (ROV & Mapping)) on NOAA Ship OKEANOS EXPLORER in the North Pacific Ocean from 2016-07-27 to 2016-08-19 (NCEI Accession 0156560)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains oceanographic data collected in the deep water areas around Wake Island and along transits from Guam to Kwajalein. Operations will use the...

  5. Hawaii Institute for Marine Biology and NOAA National Ocean Service, Marine Sanctuary Program Partnership, in affiliation with the Coral Reef Assessment and Monitoring Program, 2007 Survey of the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve: Digital Still Images (NODC Accession 0052882)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Rapid Assessment Transects were conducted in 2007 in the Papahanaumokuakea Marine National Monument of the Northwest Hawaiian Islands Coral Reef Ecosystem Reserve....

  6. Physical oceanographic data collected from moorings deployed at Southeast Farallon Island by Gulf of the Farallones National Marine Sanctuary (GFNMS) and Bodega Marine Laboratory (BML) in the North Pacific Ocean from 2005-06-27 to 2011-08-19 (NODC Accession 0104198)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These are netCDF format data collected by GFNMS and BML to understand the physical processes at Southeast Farallon Island and their potential effects on marine...

  7. Hawaii Institute for Marine Biology and NOAA National Ocean Service, Marine Sanctuary Program Partnership, in affiliation with the Coral Reef Assessment and Monitoring Program, 2007 Survey of the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve: Benthic Data from Digital Still Images (NODC Accession 0000881)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Rapid Assessment Transects were conducted in 2007 in the Papahanaumokuakea Marine National Monument of the Northwest Hawaiian Islands Coral Reef Ecosystem Reserve....

  8. 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.

  9. Tectonic tremor on Vancouver Island, Cascadia, modulated by the body and surface waves of the Mw 8.6 and 8.2, 2012 East Indian Ocean earthquakes

    Science.gov (United States)

    Kundu, Bhaskar; Ghosh, Abhijit; Mendoza, Manuel; Bürgmann, Roland; Gahalaut, V. K.; Saikia, Dipankar

    2016-09-01

    The 2012 East Indian Ocean earthquake (Mw 8.6), so far the largest intraoceanic plate strike-slip event ever recorded, modulated tectonic tremors in the Cascadia subduction zone. The rate of tremor activity near Vancouver Island increased by about 1.5 times from its background level during the passage of seismic waves of this earthquake. In most cases of dynamic modulation, large-amplitude and long-period surface waves stimulate tremors. However, in this case even the small stress change caused by body waves generated by the 2012 earthquake modulated tremor activity. The tremor modulation continued during the passage of the surface waves, subsequent to which the tremor activity returned to background rates. Similar tremor modulation is observed during the passage of the teleseismic waves from the Mw 8.2 event, which occurs about 2 h later near the Mw 8.6 event. We show that dynamic stresses from back-to-back large teleseismic events can strongly influence tremor sources.

  10. Diversity of Dicotyledenous-Infecting Geminiviruses and Their Associated DNA Molecules in Southern Africa, Including the South-West Indian Ocean Islands

    Directory of Open Access Journals (Sweden)

    Lindy L. Esterhuizen

    2012-09-01

    Full Text Available The family Geminiviridae comprises a group of plant-infecting circular ssDNA viruses that severely constrain agricultural production throughout the temperate regions of the world, and are a particularly serious threat to food security in sub-Saharan Africa. While geminiviruses exhibit considerable diversity in terms of their nucleotide sequences, genome structures, host ranges and insect vectors, the best characterised and economically most important of these viruses are those in the genus Begomovirus. Whereas begomoviruses are generally considered to be either monopartite (one ssDNA component or bipartite (two circular ssDNA components called DNA-A and DNA-B, many apparently monopartite begomoviruses are associated with additional subviral ssDNA satellite components, called alpha- (DNA-as or betasatellites (DNA-βs. Additionally, subgenomic molecules, also known as defective interfering (DIs DNAs that are usually derived from the parent helper virus through deletions of parts of its genome, are also associated with bipartite and monopartite begomoviruses. The past three decades have witnessed the emergence and diversification of various new begomoviral species and associated DI DNAs, in southern Africa, East Africa, and proximal Indian Ocean islands, which today threaten important vegetable and commercial crops such as, tobacco, cassava, tomato, sweet potato, and beans. This review aims to describe what is known about these viruses and their impacts on sustainable production in this sensitive region of the world.

  11. Diversity of dicotyledenous-infecting geminiviruses and their associated DNA molecules in southern Africa, including the South-west Indian ocean islands.

    Science.gov (United States)

    Rey, Marie E C; Ndunguru, Joseph; Berrie, Leigh C; Paximadis, Maria; Berry, Shaun; Cossa, Nurbibi; Nuaila, Valter N; Mabasa, Ken G; Abraham, Natasha; Rybicki, Edward P; Martin, Darren; Pietersen, Gerhard; Esterhuizen, Lindy L

    2012-09-01

    The family Geminiviridae comprises a group of plant-infecting circular ssDNA viruses that severely constrain agricultural production throughout the temperate regions of the world, and are a particularly serious threat to food security in sub-Saharan Africa. While geminiviruses exhibit considerable diversity in terms of their nucleotide sequences, genome structures, host ranges and insect vectors, the best characterised and economically most important of these viruses are those in the genus Begomovirus. Whereas begomoviruses are generally considered to be either monopartite (one ssDNA component) or bipartite (two circular ssDNA components called DNA-A and DNA-B), many apparently monopartite begomoviruses are associated with additional subviral ssDNA satellite components, called alpha- (DNA-αs) or betasatellites (DNA-βs). Additionally, subgenomic molecules, also known as defective interfering (DIs) DNAs that are usually derived from the parent helper virus through deletions of parts of its genome, are also associated with bipartite and monopartite begomoviruses. The past three decades have witnessed the emergence and diversification of various new begomoviral species and associated DI DNAs, in southern Africa, East Africa, and proximal Indian Ocean islands, which today threaten important vegetable and commercial crops such as, tobacco, cassava, tomato, sweet potato, and beans. This review aims to describe what is known about these viruses and their impacts on sustainable production in this sensitive region of the world.

  12. A Geospatial Appraisal of Ecological and Geomorphic Change on Diego Garcia Atoll, Chagos Islands (British Indian Ocean Territory

    Directory of Open Access Journals (Sweden)

    Holly East

    2012-11-01

    Full Text Available This study compiled a wide range of modern and historic geospatial datasets to examine ecological and geomorphic change at Diego Garcia Atoll across a 38-year period (1967–2005. This remarkable collection of spatially referenced information offered an opportunity to advance our understanding of the nature and extent of environmental change that has taken place with the construction of the military airbase at Diego Garcia. Changes assessed included movements of the lagoon rim shorelines, changes in the terrestrial vegetation on the lagoon rim and amendments to the bathymetry of the lagoon basin through dredging activities. Data compiled included detailed shoreline and vegetation maps produced as part of the H.M.S. Vidal Indian Ocean Expedition (1967, three Ikonos satellite images acquired in 2005 that collectively covered the complete Atoll area, a ground truthing field dataset collected in the northern section of the lagoon for the purpose of seafloor mapping (2005, observational evidence of shoreline erosion including photographs and descriptions of seawater inundations and bathymetric soundings from five independent surveys of the lagoon floor (1967, 1985, 1987, 1988 and 1997. Results indicated that much of the change along the lagoon rim is associated with the expansion of the inner lagoon shoreline as a result of the construction of the military airbase, with an estimated increase in land area of 3.01 km2 in this portion of the atoll rim. Comparisons of 69 rim width transects measured from 1967 and 2005 indicated that shorelines are both eroding (26 transects and accreting (43 transects. Within a total vegetated area of 24 km2, there was a notable transition from Cocos Woodland to Broadleaf Woodland for a land area of 5.6 km2. From the hydrographic surveys, it was estimated that approximately 0.55 km3 of carbonate sediment material has been removed from the northwest quadrant of the lagoon, particularly in the vicinity of the Main

  13. Sand Point, Alaska Tsunami Forecast Grids for MOST Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sand Point, Alaska Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST) model....

  14. Coastal hazards and groundwater salinization on low coral islands.

    Science.gov (United States)

    Terry, James P.; Chui, T. F. May

    2016-04-01

    Remote oceanic communities living on low-lying coral islands (atolls) without surface water rely for their survival on the continuing viability of fragile groundwater resources. These exist in the form of fresh groundwater lenses (FGLs) that develop naturally within the porous coral sand and gravel substrate. Coastal hazards such as inundation by high-energy waves driven by storms and continuing sea-level rise (SLR) are among many possible threats to viable FGL size and quality on atolls. Yet, not much is known about the combined effects of wave washover during powerful storms and SLR on different sizes of coral island, nor conversely how island size influences lens resilience against damage. This study investigates FGL damage by salinization (and resilience) caused by such coastal hazards using a modelling approach. Numerical modelling is carried out to generate steady-state FGL configurations at three chosen island sizes (400, 600 and 800 m widths). Steady-state solutions reveal how FGL dimensions are related in a non-linear manner to coral island size, such that smaller islands develop much more restricted lenses than larger islands. A 40 cm SLR scenario is then imposed. This is followed by transient simulations to examine storm-induced wave washover and subsequent FGL responses to saline damage over a 1 year period. Smaller FGLs display greater potential for disturbance by SLR, while larger and more robust FGLs tend to show more resilience. Further results produce a somewhat counterintuitive finding: in the post-SLR condition, FGL vulnerability to washover salinization may actually be reduced, owing to the thinner layer of unsaturated substrate lying above the water table into which saline water can infiltrate during a storm event. Nonetheless, combined washover and SLR impacts imply overall that advancing groundwater salinization may lead to some coral islands becoming uninhabitable long before they are completely submerged by sea-level rise, thereby calling

  15. Combined multibeam and bathymetry data from Rhode Island Sound and Block Island Sound: a regional perspective

    Science.gov (United States)

    Poppe, Lawrence J.; McMullen, Katherine Y.; Danforth, William W.; Blankenship, Mark R.; Clos, Andrew R.; Glomb, Kimberly A.; Lewit, Peter G.; Nadeau, Megan A.; Wood, Douglas A.; Parker, Castleton E.

    2014-01-01

    Detailed bathymetric maps of the sea floor in Rhode Island and Block Island Sounds are of great interest to the New York, Rhode Island, and Massachusetts research and management communities because of this area's ecological, recreational, and commercial importance. Geologically interpreted digital terrain models from individual surveys provide important benthic environmental information, yet many applications of this information require a geographically broader perspective. For example, individual surveys are of limited use for the planning and construction of cross-sound infrastructure, such as cables and pipelines, or for the testing of regional circulation models. To address this need, we integrated 14 contiguous multibeam bathymetric datasets that were produced by the National Oceanic and Atmospheric Administration during charting operations into one digital terrain model that covers much of Block Island Sound and extends eastward across Rhode Island Sound. The new dataset, which covers over 1244 square kilometers, is adjusted to mean lower low water, gridded to 4-meter resolution, and provided in Universal Transverse Mercator Zone 19, North American Datum of 1983 and geographic World Geodetic Survey of 1984 projections. This resolution is adequate for sea-floor feature and process interpretation but is small enough to be queried and manipulated with standard Geographic Information System programs and to allow for future growth. Natural features visible in the data include boulder lag deposits of winnowed Pleistocene strata, sand-wave fields, and scour depressions that reflect the strength of oscillating tidal currents and scour by storm-induced waves. Bedform asymmetry allows interpretations of net sediment transport. Anthropogenic features visible in the data include shipwrecks and dredged channels. Together the merged data reveal a larger, more continuous perspective of bathymetric topography than previously available, providing a fundamental framework for

  16. Federal Outer Continental Shelf (OCS) Sand and Gravel Borrow Areas (Lease Areas)

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — Federal outer Continental Shelf (OCS) Sand and Gravel Borrow Areas (Lease Areas) are polygons which are maintained by the Bureau of Ocean Energy Management (BOEM),...

  17. Landscapes of Santa Rosa Island, Channel Islands National Park, California

    Science.gov (United States)

    Schumann, R. Randall; Minor, Scott A.; Muhs, Daniel R.; Pigati, Jeffery S.

    2014-01-01

    Santa Rosa Island (SRI) is the second-largest of the California Channel Islands. It is one of 4 east–west aligned islands forming the northern Channel Islands chain, and one of the 5 islands in Channel Islands National Park. The landforms, and collections of landforms called landscapes, of Santa Rosa Island have been created by tectonic uplift and faulting, rising and falling sea level, landslides, erosion and deposition, floods, and droughts. Landscape features, and areas delineating groups of related features on Santa Rosa Island, are mapped, classified, and described in this paper. Notable landscapes on the island include beaches, coastal plains formed on marine terraces, sand dunes, and sand sheets. In this study, the inland physiography has been classified into 4 areas based on relief and degree of fluvial dissection. Most of the larger streams on the island occupy broad valleys that have been filled with alluvium and later incised to form steep- to vertical-walled arroyos, or barrancas, leaving a relict floodplain above the present channel. A better understanding of the processes and mechanisms that created these landscapes enhances visitors’ enjoyment of their surroundings and contributes to improving land and resource management strategies in order to optimize and balance the multiple goals of conservation, preservation, restoration, and visitor experience.

  18. Influence green sand system by core sand additions

    OpenAIRE

    N. Špirutová; J. Beňo; V. Bednářová; J. Kříž; M. Kandrnál

    2012-01-01

    Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron) are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this co...

  19. CRED 10m Gridded multibeam bathymetry of Maug Island(s), Commonwealth of the Northern Mariana Islands (CNMI).

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry shelf, bank and slope environments of Maug Island(s), CNMI. Bottom coverage was achieved in depths between 4 and 3275 meters. This 10-m grid also...

  20. Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Borup, Marianne; Hedegaard, Jette

    The Soil Mechanics Laboratory has started performing tests with a new sand, Baskarp No 15. Baskarp No 15 is a graded sand from Sweden. The shapes of the largest grains are round, while the small grains have sharp edges. The main part of of Baskarp No 15 is quarts, but it also contains feldspar...... and biotit. Mainly the sand will be used for tests concerning the development og the theory of building up pore pressure in sand, L. B. Ibsen 1993....

  1. Sedimentology of Coastal Deposits in the Seychelles Islands—Evidence of the Indian Ocean Tsunami 2004

    Science.gov (United States)

    Nentwig, Vanessa; Bahlburg, Heinrich; Monthy, Devis

    2015-03-01

    The Seychelles, an archipelago in the Indian Ocean at a distance of 4,500-5,000 km from the west coast of Sumatra, were severely affected by the December 26, 2004 tsunami with wave heights up to 4 m. Since the tsunami history of small islands often remains unclear due to a young historical record, it is important to study the geological traces of high energy events preserved along their coasts. We conducted a survey of the impact of the 2004 Indian Ocean tsunami on the inner Seychelles islands. In detail we studied onshore tsunami deposits in the mangrove forest at Old Turtle Pond in the Curieuse Marine National Park on the east coast of Curieuse Island. It is thus protected from anthropogenic interference. Towards the sea it was shielded until the tsunami in 2004 by a 500 m long and 1.5 m high causeway which was set up in 1909 as a sediment trap and assuring a low energetic hydrodynamic environment for the protection of the mangroves. The causeway was destroyed by the 2004 Indian Ocean Tsunami. The tsunami caused a change of habitat by the sedimentation of sand lobes in the mangrove forest. The dark organic rich mangrove soil (1.9 Φ) was covered by bimodal fine to medium carbonate sand (1.7-2.2 Φ) containing coarser carbonate shell fragments and debris. Intertidal sediments and the mangrove soil acted as sources of the lobe deposits. The sand sheet deposited by the tsunami is organized into different lobes. They extend landwards to different inundation distances as a function of the morphology of the onshore area. The maximum extent of 180 m from the shoreline indicates the minimum inundation distance to the tsunami. The top parts of the sand lobes cover the pneumatophores of the mangroves. There is no landward fining trend along the sand lobes and normal grading of the deposits is rare, occurring only in 1 of 7 sites. The sand lobe deposits also lack sedimentary structures. On the surface of the sand lobes numerous mostly fragmented shells of bivalves and

  2. Lund Sand No 0

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Jakobsen, Finn Rosendal

    During the last 15 years the Geotechnical Engineering Group (GEG) at Aalborg University has performed triaxial tests with a sand called Lund No 0. Lund No 0 is a graded sand from a gravel pit near Horsens in Denmark. For the classification of the sand the following tests have been performed: Sieve...

  3. Benthic Mapping in Long Island Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — QTCView is used with an incorporated depthfinder to create a sonar map of the bottom to the west of the Charles Island, in Long Island Sound in Connecticut waters....

  4. Bartolome Island, Galapagos Stable Oxygen Calibration Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Galapagos Coral Stable Oxygen Calibration Data. Sites: Bartolome Island: 0 deg, 17'S, 90 deg 33' W. Champion Island: 1 deg, 15'S, 90 deg, 05' W. Urvina Bay (Isabela...

  5. Sea-floor geology of Long Island Sound north of Duck Pond Point, New York

    Science.gov (United States)

    McMullen, K.Y.; Poppe, L.J.; Danforth, W.W.; Blackwood, D.S.; Schaer, J.D.; Glomb, K.A.; Doran, E.F.

    2012-01-01

    The U.S. Geological Survey, the National Oceanic and Atmospheric Administration (NOAA), and the Connecticut Department of Environmental Protection are mapping the sea floor in coastal areas of the northeastern United States. As part of the project, more than 100 square kilometers of multibeam-echosounder data, 23 sediment samples, bottom video, and 86 still photographs were obtained from an area in Long Island Sound north of Duck Pond Point, New York, in the study area of NOAA survey H11999. This report delineates the sediment types and sea-floor features found within this area in order to better understand the sea-floor processes occurring in this part of Long Island Sound. The sea floor in the study area is dominated by ubiquitous sand-wave fields and three northeast-southwest trending bathymetric depressions. Barchanoid and transverse sand waves, including sinusoidal, bifurcating, arced, and straight-crested morphologies, are variably present. Asymmetrical sand-wave profiles indicate a westward to southwestward direction of sediment transport in most of the study area; current ripples and megaripples on the stoss slopes of the sand waves indicate transport is ongoing. The majority of the sediment on the sea floor is sand, although bouldery, gravelly, and muddy sediments are also present. Gray, cohesive mud crops out on the walls of some of the scour depressions associated with the troughs of large sand waves. Clasts of the muddy sediment scattered on the sea floor around the depressions demonstrate the intensity of the scour and suggest erosion of the underlying distal deltaic sediments.

  6. NOAA Integrated Ocean and Coastal Mapping (IOCM) orthorectified mosaic image tiles, Cutts Island to Prouts Neck, Penobscot, and Reversing Falls, Maine, June 2011 (NODC Accession 0100008)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains both true color (RGB) and infrared (IR) ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping...

  7. NOAA Integrated Ocean and Coastal Mapping (IOCM) orthorectified mosaic image tiles, Merrimack River and Plum Island Sound, Massachusetts, June 2011 (NODC Accession 0103944)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains both true color (RGB) and infrared (IR) ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping...

  8. AFSC/RACE/SAP/Foy: The effects of ocean acidification on ovigerous Tanner crab size, calcium, and magnesium content. : Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we conducted laboratory experiments with adult ovigerous females of the economically important southern Tanner crab,...

  9. Zooplankton species identification and counts data from drifting station ARLIS II and Fletchers ice island T-3 in the Arctic Ocean from 19521229 to 19680129 (NODC Accession 6900643)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are counts of 3 copepod species collected during plankton tows in the Arctic Ocean from December 1952 through January 1968 by the University of...

  10. 2014 NOAA Ortho-rectified Mean High Water Color Mosaic of Dewees Island to Bulls Bay (ICW), South Carolina: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2014 NOAA Ortho-rectified Mean High Water Near-Infrared Mosaic of Dewees Island to Bulls Bay (ICW), South Carolina: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2014 NOAA Ortho-rectified Mean High Water Near-Infrared Mosaic of Edisto Island, South Carolina: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2012 NOAA Ortho-rectified Mosaic of South Carolina: Northeast Point to Murphy Island, Mean Lower Low Water Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2011 NOAA Ortho-rectified Mosaic of Christiansted of St. Johns, U.S. Virgin Islands: Integrated Ocean and Coastal Mapping Product (NODC Accession 0086076)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2014 NOAA Ortho-rectified Mean Low Low Water Color Mosaic of Dewees Island to Bulls Bay (ICW), South Carolina: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2014 NOAA Ortho-rectified Mean Low Low Water Near-Infrared Mosaic of Dewees Island to Bulls Bay (ICW), South Carolina: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. Sea-floor morphology and sedimentary environments of western Block Island Sound, northeast of Gardiners Island, New York

    Science.gov (United States)

    McMullen, Katherine Y.; Poppe, Lawrence J.; Danforth, William W.; Blackwood, Dann S.; Clos, Andrew R.; Parker, Castle E.

    2014-01-01

    Multibeam-echosounder data, collected during survey H12299 by the National Oceanic and Atmospheric Administration in a 162-square-kilometer area of Block Island Sound, northeast of Gardiners Island, New York, are used along with sediment samples and bottom photography, collected at 37 stations in this area by the U.S. Geological Survey during cruise 2013-005-FA, to interpret sea-floor features and sedimentary environments. These data and interpretations provide important base maps for future studies of the sea floor, focused, for example, on benthic ecology and resource management. The features and sedimentary environments on the sea floor are products of the glacial history and modern tidal regime. Features include bedforms such as sand waves and megaripples, boulders, a large current-scoured depression, exposed glaciolacustrine sediments, and areas of modern marine sediment. Sand covers much of the study area and is often in the form of sand waves and megaripples, which indicate environments characterized by coarse-grained bedload transport. Boulders and gravelly lag deposits, which indicate environments of erosion or nondeposition, are found off the coast of Gardiners Island and on bathymetric highs, probably marking areas where deposits associated with recessional ice-front positions, the northern flank of the terminal moraine, or coastal-plain sediments covered with basal till are exposed. Bottom photographs and video of boulders show that they are commonly covered with sessile fauna. Strong tidal currents have produced the deep scour depression along the northwestern edge of the study area. The eastern side of this depression is armored with a gravel lag. Sea-floor areas characterized by modern marine sediments appear featureless at the 2-meter resolution of the bathymetry and flat to current rippled in the photography. These modern environments are indicative of sediment sorting and reworking.

  18. Sea-floor geology in northwestern Block Island Sound, Rhode Island

    Science.gov (United States)

    McMullen, Katherine Y.; Poppe, Lawrence J.; Ackerman, Seth D.; Blackwood, Dann S.; Woods, D.A.

    2014-01-01

    Multibeam-echosounder and sidescan-sonar data, collected by the National Oceanic and Atmospheric Administration in a 69-square-kilometer area of northwestern Block Island Sound, are used with sediment samples, and still and video photography of the sea floor, collected by the U.S. Geological Survey at 43 stations within this area, to interpret the sea-floor features and sedimentary environments. Features on the sea floor include boulders, sand waves, scour depressions, modern marine sediments, and trawl marks. Boulders, which are often several meters wide, are found in patches in the shallower depths and tend to be overgrown with sessile flora and fauna. They are lag deposits of winnowed glacial drift, and reflect high-energy environments characterized by processes associated with erosion and nondeposition. Sand waves and megaripples tend to have crests that either trend parallel to shore with 20- to 50-meter (m) wavelengths or trend perpendicular to shore with several-hundred-meter wavelengths. The sand waves reflect sediment transport directions perpendicular to shore by waves, and parallel to shore by tidal or wind-driven currents, respectively. Scour depressions, which are about 0.5 m lower than the surrounding sea floor, have floors of gravel and coarser sand than bounding modern marine sediments. These scour depressions, which are conspicuous in the sidescan-sonar data because of their more highly reflective coarser sediment floors, are likely formed by storm-generated, seaward-flowing currents and maintained by the turbulence in bottom currents caused by their coarse sediments. Areas of the sea floor with modern marine sediments tend to be relatively flat to current-rippled and sandy.

  19. Benthic substrate classification map: Gulf Islands National Seashore

    Science.gov (United States)

    Lavoie, Dawn; Flocks, James; Twichell, Dave; Rose, Kate

    2013-01-01

    The 2005 hurricane season was devastating for the Mississippi Gulf Coast. Hurricane Katrina caused significant degradation of the barrier islands that compose the Gulf Islands National Seashore (GUIS). Because of the ability of coastal barrier islands to help mitigate hurricane damage to the mainland, restoring these habitats prior to the onset of future storms will help protect the islands themselves and the surrounding habitats. During Hurricane Katrina, coastal barrier islands reduced storm surge by approximately 10 percent and moderated wave heights (Wamsley and others, 2009). Islands protected the mainland by preventing ocean waves from maintaining their size as they approached the mainland. In addition to storm protection, it is advantageous to restore these islands to preserve the cultural heritage present there (for example, Fort Massachusetts) and because of the influence that these islands have on marine ecology. For example, these islands help maintain a salinity regime favorable to oysters in the Mississippi Sound and provide critical habitats for many migratory birds and endangered species such as sea turtles (Chelonia mydas, Caretta caretta, and Dermochelys coriacea), Gulf sturgeon (Acipenser oxyrinchus desotoi), and piping plovers (Charadrius melodus) (U.S. Army Corps of Engineers, 2009a). As land manager for the GUIS, the National Park Service (NPS) has been working with the State of Mississippi and the Mobile District of the U.S. Army Corps of Engineers to provide a set of recommendations to the Mississippi Coastal Improvements Program (MsCIP) that will guide restoration planning. The final set of recommendations includes directly renourishing both West Ship Island (to protect Fort Massachusetts) and East Ship Island (to restore the French Warehouse archaeological site); filling Camille Cut to recreate a continuous Ship Island; and restoring natural regional sediment transport processes by placing sand in the littoral zone just east of Petit Bois

  20. 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.

  1. Backscatter 0.5m TIFF Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography...

  2. CRED 20m Gridded bathymetry of Necker Islands, Northwestern Hawaiian Islands, USA (NetCDF format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry of the shelf and slope environments of Necker Island, Northwestern Hawaiian Islands, Hawaii, USA. This netCDF includes multibeam bathymetry from...

  3. Sea-floor morphology and sedimentary environments in western Block Island Sound, offshore of Fishers Island, New York

    Science.gov (United States)

    McMullen, Katherine Y.; Poppe, Lawrence J.; Danforth, William W.; Blackwood, Dann S.; Winner, William G.; Parker, Castle E.

    2015-01-01

    Multibeam-bathymetric and sidescan-sonar data, collected by the National Oceanic and Atmospheric Administration in a 114-square-kilometer area of Block Island Sound, southeast of Fishers Island, New York, are combined with sediment samples and bottom photography collected by the U.S. Geological Survey from 36 stations in this area in order to interpret sea-floor features and sedimentary environments. These interpretations and datasets provide base maps for studies on benthic ecology and resource management. The geologic features and sedimentary environments on the sea floor are products of the area’s glacial history and modern processes. These features include bedrock, drumlins, boulders, cobbles, large current-scoured bathymetric depressions, obstacle marks, and glaciolacustrine sediments found in high-energy sedimentary environments of erosion or nondeposition; and sand waves and megaripples in sedimentary environments characterized by coarse-grained bedload transport. Trawl marks are preserved in lower energy environments of sorting and reworking. This report releases the multibeam-bathymetric, sidescan-sonar, sediment, and photographic data and interpretations of the features and sedimentary environments in Block Island Sound, offshore Fishers Island.

  4. Molecular evolutionary analysis of pH1N1 2009 influenza virus in Reunion Island, South West Indian Ocean region: a cohort study.

    Directory of Open Access Journals (Sweden)

    Hervé Pascalis

    Full Text Available BACKGROUND/OBJECTIVES: Molecular epidemiology is a powerful tool to decipher the dynamics of viral transmission, quasispecies temporal evolution and origins. Little is known about the pH1N1 molecular dynamics in general population. A prospective study (CoPanFlu-RUN was carried out in Reunion Island to characterize pH1N1 genetic variability and molecular evolution occurring in population during the pH1N1 Influenza pandemic in 2009. METHODOLOGY: We directly amplified pH1N1 genomes from 28 different nasal swabs (26 individuals from 21 households. Fifteen strains were fully sequenced and 13 partially. This includes pairs of sequences from different members of 5 separate households; and two pairs from individuals, collected at different times. We assessed the molecular evolution of pH1N1 by genetic variability and phylogenetic analyses. PRINCIPAL FINDINGS: We found that i Reunion pH1N1 sequences stemmed from global "clade 7" but shaped two phylogenetic sub-clades; ii D239E mutation was identified in the hemagglutinin protein of all Reunion sequences, a mutation which has been associated elsewhere with mild-, upper-respiratory tract pH1N1 infecting strains; iii Date estimates from molecular phylogenies predicted clade emergence some time before the first detection of pH1N1 by the epidemiological surveillance system; iv Phylogenetic relatedness was observed between Reunion pH1N1 viruses and those from other countries in South-western Indian Ocean area; v Quasispecies populations were observed within households and individuals of the cohort-study. CONCLUSIONS: Surveillance and/or prevention systems presently based on Influenza virus sequence variation should take into account that the majority of studies of pH1N1 Influenza generate genetic data for the HA/NA viral segments obtained from hospitalized-patients, which is potentially non-representative of the overall viral diversity within whole populations. Our observations highlight the importance of

  5. 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.

  6. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  7. Three Mile Island Accident Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Three Mile Island Accident Data consists of mostly upper air and wind observations immediately following the nuclear meltdown occurring on March 28, 1979, near...

  8. Sediment Analysis Network for Decision Support (SANDS)

    Science.gov (United States)

    Hardin, D. M.; Keiser, K.; Graves, S. J.; Conover, H.; Ebersole, S.

    2009-12-01

    and hurricanes on sediment disturbance, suspension, transport, and deposition in the north central Gulf of Mexico. At least five end user organizations plus the UAHuntsville’s Information Technology and Systems Center and the Geological Survey of Alabama project team, will use the products to improve measurements of water quality (Dauphin Island Sea Lab); assess sedimentation during storm events and its impact on critical coastal habitats (Alabama Department of Conservation); assess sedimentation versus sea level rise in natural marshes (Department of the Interior); and improve understanding of the impact of sediment and sediment deposits on water quality, living resources, and habitats of the estuarine environment (Mobile Bay National Estuary Program); and assess storm surge effects on coastal ecosystems (NOAA Center for Coastal Ocean Research). The products will be managed and accessed through the SANDS Portal, an on-line data repository with a user interface customized to provide data and information for specific storm events. By making multi-spectral satellite products available for multiple common storm events, SANDS will provide end users the opportunity to better analyze, detect, and identify compositions and patterns of suspended sediment and sediment deposits.

  9. Estimating the Impact of Drought on Groundwater Resources of the Marshall Islands

    Directory of Open Access Journals (Sweden)

    Brandon L. Barkey

    2017-01-01

    Full Text Available Groundwater resources of small coral islands are threatened due to short-term and long-term changes in climate. A significant short-term threat is El Niño events, which typically induce a severe months-long drought for many atoll nations in the western and central Pacific regions that exhausts rainwater supply and necessitates the use of groundwater. This study quantifies fresh groundwater resources under both average rainfall and drought conditions for the Republic of Marshall Islands (RMI, a nation composed solely of atolls and which is severely impacted by El Niño droughts. The atoll island algebraic model is used to estimate the thickness of the freshwater lens for 680 inhabited and uninhabited islands of the RMI, with a focus on the severe 1998 drought. The model accounts for precipitation, island width, hydraulic conductivity of the upper Holocene-age sand aquifer, the depth to the contact between the Holocene aquifer and the lower Pleistocene-age limestone aquifer, and the presence of a reef flat plate underlying the ocean side of the island. Model results are tested for islands that have fresh groundwater data. Results highlight the fragility of groundwater resources for the nation. Average lens thickness during typical seasonal rainfall is approximately 4 m, with only 30% of the islands maintaining a lens thicker than 4.5% and 55% of the islands with a lens less than 2.5 m thick. Thicker lenses typically occur for larger islands, islands located on the leeward side of an atoll due to lower hydraulic conductivity, and islands located in the southern region of the RMI due to higher rainfall rates. During drought, groundwater on small islands (<300 m in width is completely depleted. Over half (54% of the islands are classified as “Highly Vulnerable” to drought. Results provide valuable information for RMI water resources planners, particularly during the current 2016 El Niño drought, and similar methods can be used to quantify

  10. Sands cykliske styrke

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1992-01-01

    Sands cykliske styrke kan beskrives ved Cyclic Liquefaction, Mobilisering, Stabilization og Instant Stabilization. I artiklen beskrives hvorfor Stabilization og Instant Stabilization ikke observeres, når sands udrænede styrke undersøges i triaxial celler, der anvender prøver med dobbelt prøvehøjde....

  11. Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Bødker, Lars Bødker

    The Soil Mechanics Laboratory has started performing tests with a new sand, Baskarp No 15. Baskarp No 15 is a graded sand from Sweden. The shapes of the largest grains are round, while the small grains have sharp edges. The main part of of Baskarp No 15 is quarts, but it also contains feldspar...

  12. The diversity of Indian Ocean Heterotardigrada

    Directory of Open Access Journals (Sweden)

    Roberto SANDULLI

    2007-09-01

    Full Text Available Information about Indian Ocean tardigrades is quite scarce and in most cases refers to species in coastal coralline sediment and occasionally in abyssal mud. The present data concern species found in the intertidal sand of Coco and La Digue Islands in the Seychelles, previously unsampled for tardigrades, as well as species in subtidal sediment found at depths ranging between 1 and 60 m off the shores of the Maldive Atolls. These sediments are all very similar and consist of heterogeneous coralline sand, moderately or scarcely sorted. Sixteen species (three new to science were found in the Seychelles, belonging to Renaudarctidae, Stygarctidae, Halechiniscidae, Batillipedidae and Echiniscoididae. Diversity and evenness data are also interesting, with maximum values of H' = 2.59 and of J = 0.97. In the Maldives 25 species were found (two new to science belonging to Neostygarctidae, Stygarctidae, Halechiniscidae and Batillipedidae. Such a number of species, despite the low percentage of tardigrade fauna (only 0.6% of the total meiofauna, contributes to the high values of both diversity and evenness, with H' ranging between 1.5 and 2.6 and J between 0.6 and 1. The Indian Ocean tardigrade fauna currently numbers 31 species of Arthrotardigrada and 2 species of Echiniscoidida. In the present study, Arthrotardigrada are the most abundant and all the families are present except Neoarctidae. Halechiniscidae is present with all the sub-families (except Euclavartinae, thus contributing to the high diversity values. Furthermore, 18 species, representing more than 50% of the total marine tardigrade fauna, are new records for the Indian Ocean, including five species new to science.

  13. Local inundation distances and regional tsunami recurrence in the Indian Ocean inferred from luminescence dating of sandy deposits in Thailand

    Science.gov (United States)

    Brill, D.; Klasen, N.; Jankaew, K.; Brückner, H.; Kelletat, D.; Scheffers, A.; Scheffers, S.

    2012-07-01

    The Holocene beach-ridge plain of Phra Thong Island (Ko Phra Thong, SW Thailand) provides sedimentary evidence of several palaeotsunamis, in addition to the deposit of the 2004 Indian Ocean tsunami. Due to poor preservation conditions, these palaeoevent layers are restricted to swales. Correlation across beach ridges, which is important e.g. to reconstruct inundation distances, remains a major challenge. A primary tool for establishing a precisely confined correlation of the sand sheets is the use of chronological data. Since the application of radiocarbon dating is limited by the scarcity of appropriate material, this study utilised optically stimulated luminescence (OSL) dating of tsunamigenic quartz grains. Generally, the sediments showed favourable luminescence properties regarding signal intensity, dose recovery and thermal stability. Disturbances of the OSL signal due to partial bleaching were corrected using the minimum age model. At least three palaeoevents - being 490-550, 925-1035 and 1740-2000 yr old - were distinguished by dating the discontinuous sand sheets at four different sites. Besides this chronological framework, the OSL data provide the opportunity to correlate the discontinuous sand sheets between spatially separated sites within the same swale as well as across ridges. This allows for first estimates of inundation distances for the palaeotsunamis documented on Phra Thong Island. Furthermore, the two younger events overlap in age with contemporaneous tsunami and earthquake evidence from other coasts bordering the Indian Ocean.

  14. Local inundation distances and regional tsunami recurrence in the Indian Ocean inferred from luminescence dating of sandy deposits in Thailand

    Directory of Open Access Journals (Sweden)

    D. Brill

    2012-07-01

    Full Text Available The Holocene beach-ridge plain of Phra Thong Island (Ko Phra Thong, SW Thailand provides sedimentary evidence of several palaeotsunamis, in addition to the deposit of the 2004 Indian Ocean tsunami. Due to poor preservation conditions, these palaeoevent layers are restricted to swales. Correlation across beach ridges, which is important e.g. to reconstruct inundation distances, remains a major challenge. A primary tool for establishing a precisely confined correlation of the sand sheets is the use of chronological data. Since the application of radiocarbon dating is limited by the scarcity of appropriate material, this study utilised optically stimulated luminescence (OSL dating of tsunamigenic quartz grains. Generally, the sediments showed favourable luminescence properties regarding signal intensity, dose recovery and thermal stability. Disturbances of the OSL signal due to partial bleaching were corrected using the minimum age model. At least three palaeoevents – being 490–550, 925–1035 and 1740–2000 yr old – were distinguished by dating the discontinuous sand sheets at four different sites. Besides this chronological framework, the OSL data provide the opportunity to correlate the discontinuous sand sheets between spatially separated sites within the same swale as well as across ridges. This allows for first estimates of inundation distances for the palaeotsunamis documented on Phra Thong Island. Furthermore, the two younger events overlap in age with contemporaneous tsunami and earthquake evidence from other coasts bordering the Indian Ocean.

  15. Regional Ocean Modeling System (ROMS): Samoa

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 7-day, 3-hourly forecast for the region surrounding the islands of Samoa at approximately 3-km resolution. While considerable...

  16. Regional Ocean Modeling System (ROMS): CNMI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Regional Ocean Modeling System (ROMS) 7-day, 3-hourly forecast for the region surrounding the Commonwealth of the Northern Mariana Islands (CNMI) at approximately...

  17. Broadband Scattering from Sand and Sand/Mud Sediments with Extensive Environmental Characterization

    Science.gov (United States)

    2017-01-30

    frequency sound speed and attenuation measurements in sandy sediments with a portable velocimeter.” (4) Proceedings from the 2nd International...Bay, FL off the shore of Shell Island. The sediment consisted of the 15 cm mud layer overlying a muddy, coarse sand basement. Scattering data was...Demoulin, X., L. Guillon, and B.T. Hefner (2017), “High-frequency sound speed and attenuation measurements in sandy sediments with a portable

  18. 2-m Bathymetric Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11445 in Long Island Sound, North of Plum Island, New York (H11445_2M_GEO, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the Connecticut Department of Environmental Protection and National Oceanic and Atmospheric Administration...

  19. 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.

  20. Mesoscale geomorphic change on low energy barrier islands in Chesapeake Bay, U.S.A.

    Science.gov (United States)

    Cooper, J. Andrew G.

    2013-10-01

    energy barrier islands closely resemble open ocean barrier islands. Continued reworking leads to widening of the inlets with consequent loss of constriction of tidal flow. The tidal deltas are, thus, no longer maintained and ultimately the island system disintegrates through inlet widening and is transformed to subtidal shoals. Barrier islands at various stages in this evolutionary cycle can be observed around the bay. Mid-bay barrier islands are affected by wave processes from both sides. This helps maintain the barrier island form and enables barrier islands to persist as sediment is exchanged between both sides of the island. Rates of barrier island translation are extremely high (up to 30 m/year over a 12 year period). This is attributed to the low volume of sand, which facilitates complete rollover in short periods. Accelerated sea level rise is likely to hasten the translation rates of marsh fringe barrier islands. The rapid disintegration of most spits compared to the persistence of marsh fringe barrier islands points to a reliance on the marsh as a stabilising point. If the marshes are overstepped by rising sea level as appears to be happening, the complete disintegration of the barrier islands is highly likely.

  1. Wind speed variability over the Canary Islands, 1948-2014: focusing on trend differences at the land-ocean interface and below-above the trade-wind inversion layer

    Science.gov (United States)

    Azorin-Molina, Cesar; Menendez, Melisa; McVicar, Tim R.; Acevedo, Adrian; Vicente-Serrano, Sergio M.; Cuevas, Emilio; Minola, Lorenzo; Chen, Deliang

    2017-08-01

    This study simultaneously examines wind speed trends at the land-ocean interface, and below-above the trade-wind inversion layer in the Canary Islands and the surrounding Eastern North Atlantic Ocean: a key region for quantifying the variability of trade-winds and its response to large-scale atmospheric circulation changes. Two homogenized data sources are used: (1) observed wind speed from nine land-based stations (1981-2014), including one mountain weather station (Izaña) located above the trade-wind inversion layer; and (2) simulated wind speed from two atmospheric hindcasts over ocean (i.e., SeaWind I at 30 km for 1948-2014; and SeaWind II at 15 km for 1989-2014). The results revealed a widespread significant negative trend of trade-winds over ocean for 1948-2014, whereas no significant trends were detected for 1989-2014. For this recent period wind speed over land and ocean displayed the same multi-decadal variability and a distinct seasonal trend pattern with a strengthening (late spring and summer; significant in May and August) and weakening (winter-spring-autumn; significant in April and September) of trade-winds. Above the inversion layer at Izaña, we found a predominance of significant positive trends, indicating a decoupled variability and opposite wind speed trends when compared to those reported in boundary layer. The analysis of the Trade Wind Index (TWI), the North Atlantic Oscillation Index (NAOI) and the Eastern Atlantic Index (EAI) demonstrated significant correlations with the wind speed variability, revealing that the correlation patterns of the three indices showed a spatio-temporal complementarity in shaping wind speed trends across the Eastern North Atlantic.

  2. Islands in the ice

    DEFF Research Database (Denmark)

    Jørgensen, Tina; Kjær, Kurt H.; Haile, James Seymour

    2012-01-01

    Nunataks are isolated bedrocks protruding through ice sheets. They vary in age, but represent island environments in 'oceans' of ice through which organism dispersals and replacements can be studied over time. The J.A.D. Jensen's Nunataks at the southern Greenland ice sheet are the most isolated ...

  3. Sand and Gravel Deposits

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset is a statewide polygon coverage of sand, gravel, and stone resources. This database includes the best data available from the VT Agency of Natural...

  4. Sand and Gravel Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

  5. Vestled - Hvide Sande

    DEFF Research Database (Denmark)

    Juel-Christiansen, Carsten; Hesselbjerg, Marianne; Schønherr, Torben

    2009-01-01

    Værket Vestled i Hvide Sande præsenteret i sammenhæng af 1000 nutidige landskabsarkitektoniske arbejder fra hele verden, hvor hvert værk vises på én side......Værket Vestled i Hvide Sande præsenteret i sammenhæng af 1000 nutidige landskabsarkitektoniske arbejder fra hele verden, hvor hvert værk vises på én side...

  6. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) H11320 Sidescan Sonar Mosaic in Rhode Island Sound (H11320ENVIRONS)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  7. 45-m ArcRaster Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11322 in Western Rhode Island Sound (H11322_UTM45M, UTM19)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial...

  8. 2-m Bathymetric Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11996 in Rhode Island Sound (H11996_2M_GEO, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  9. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H12296 in Block Island Sound (H12296_INTERP shapefile, Geographic, WGS 84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  10. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H12023 in Block Island Sound (H12023_INTERP shapefile, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  11. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H11995 in Rhode Island Sound (H11995_INTERP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  12. Interpretation of Sedimentary Environments from National Oceanic and Atmospheric Administration (NOAA) Survey H11997 Offshore in Eastern Long Island Sound (H11997_SEDENV.SHP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  13. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H11995 in Rhode Island Sound (H11995_INTERP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the...

  14. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H12023 in Block Island Sound (H12023_INTERP shapefile, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the...

  15. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H11996 in Rhode Island Sound (H11996_INTERP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  16. EX1002 Legs 1 through 3 ROV Focus (EX1002, EM302) on NOAA Ship Okeanos Explorer in Hawaiian Islands, North Pacific Ocean

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This cruise covers the integration of the IFE ROV Little Hercules and OER camera platform into the EX, as well as subsequent shakedown and field trial cruises...

  17. Color GeoTIFF of the Bathymetry of National Oceanic and Atmospheric Administration (NOAA) Survey H11321 in Central Rhode Island Sound (H11321_GEO.TIF. Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial...

  18. H11321_GEO45M: 45-m Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11321 in Central Rhode Island Sound (Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial...

  19. Interpretation of National Oceanic and Atmospheric Administration Survey H11321 Sidescan-Sonar Image, Central Rhode Island Sound (H11321INTERP shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  20. 45-m ArcRaster Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11322 in Western Rhode Island Sound (H11322_UTM45M, UTM19)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial...

  1. 45-m Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11321 in Central Rhode Island Sound (H11321_GEO45M, Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial...

  2. Interpretation of Sea Floor Features of National Oceanic and Atmospheric Administration (NOAA) H11320 Sidescan Sonar and Bathymetric Data from Rhode Island Sound (H11320INTERP)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  3. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) H11320 Sidescan Sonar Mosaic in Rhode Island Sound (H11320ENVIRONS)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  4. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) Survey H11322, Western Rhode Island Sound (H11322ENVIRONS, Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  5. Interpretation of Sidescan-Sonar Imagery of National Oceanic and Atmospheric Administration (NOAA) Survey H11322 in Western Rhode Island Sound (H11322INTERP, Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  6. 2-m Bathymetric ArcRaster Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11250 of Eastern Long Island Sound (H11250U, UTM, Zone 18)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has...

  7. Interpretation of Sidescan-Sonar Imagery of National Oceanic and Atmospheric Administration (NOAA) Survey H11322 in Western Rhode Island Sound (H11322INTERP, Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  8. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) Survey H11321, Central Rhode Island Sound (H11321ENVIRONS shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  9. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H12296 in Block Island Sound (H12296_INTERP shapefile, Geographic, WGS 84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  10. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H11995 in Rhode Island Sound (H11995_INTERP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  11. Interpretation of Bottom Features from National Oceanic and Atmospheric Administration (NOAA) Survey H12023 in Block Island Sound (H12023_INTERP shapefile, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal...

  12. Islands in the Stream 2001 on NOAA Ship Gordon Gunter in the North Atlantic Ocean and the Gulf of Mexico between May 10, 2001 and October 4, 2001

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Library Catalog may include: Data Management Plans, Cruise Plans, Cruise Summary Reports, Scientific "Quick Look Reports", Video Annotation Logs, Image Collections,...

  13. NOAA Integrated Ocean and Coastal Mapping (IOCM) orthorectified mosaic image tiles, Terrebonne and Timbalier Bays Barrier Islands, Louisiana 2007-2008 (NODC Accession 0075828)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — AERO-METRIC, INC. (AME) provided aerial photographic imagery collected by NOAA along the shoreline of Louisiana. The purpose of the imagery was to provide digital...

  14. H11321_GEO45M: 45-m Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H11321 in Central Rhode Island Sound (Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial...

  15. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  16. Emergent Behavior of Coupled Barrier Island - Resort Systems

    Science.gov (United States)

    McNamara, D. E.; Werner, B. T.

    2004-12-01

    Barrier islands are attractive sites for resorts. Natural barrier islands experience beach erosion and island overwash during storms, beach accretion and dune building during inter-storm periods, and migration up the continental shelf as sea level rises. Beach replenishment, artificial dune building, seawalls, jetties and groins have been somewhat effective in protecting resorts against erosion and overwash during storms, but it is unknown how the coupled system will respond to long-term sea level rise. We investigate coupled barrier island - resort systems using an agent-based model with three components: natural barrier islands divided into a series of alongshore cells; resorts controlled by markets for tourism and hotel purchases; and coupling via storm damage to resorts and resort protection by government agents. Modeled barrier islands change by beach erosion, island overwash and inlet cutting during storms, and beach accretion, tidal delta growth and dune and vegetation growth between storms. In the resort hotel market, developer agents build hotels and hotel owning agents purchase them using predictions of future revenue and property appreciation, with the goal of maximizing discounted utility. In the tourism market, hotel owning agents set room rental prices to maximize profit and tourist agents choose vacation destinations maximizing a utility based on beach width, price and word-of-mouth. Government agents build seawalls, groins and jetties, and widen the beach and build up dunes by adding sand to protect resorts from storms, enhance beach quality, and maximize resort revenue. Results indicate that barrier islands and resorts evolve in a coupled manner to resort size saturation, with resorts protected against small-to-intermediate-scale storms under fairly stable sea level. Under extended, rapidly rising sea level, protection measures enhance the effect of large storms, leading to emergent behavior in the form of limit cycles or barrier submergence

  17. 2010 U.S. Geological Survey (USGS) Topographic Lidar: Channel Islands, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Terrapoint collected LiDAR for 197 square miles covering five islands off the coast of Los Angeles, California. These islands are part of the Channel Islands...

  18. 2010 U.S. Geological Survey (USGS) Topographic Lidar: Channel Islands, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Terrapoint collected LiDAR for 197 square miles covering five islands off the coast of Los Angeles, California. These islands are part of the Channel Islands...

  19. Rhodoliths and coralliths of Muri Lagoon, Rarotonga, Cook Islands

    Science.gov (United States)

    Scoffin, Terence P.; Stoddart, David R.; Tudhope, Alexander W.; Woodroffe, Colin

    1985-09-01

    Free-living massive and branching spheroidal growths (about 5 cm diameter) of calcareous red algae (rhodoliths) and corals (coralliths) occur in abundance on the sea bed of shallow Muri Lagoon on Rarotonga's reef flat. The rhodoliths are composed of one or more species of Neogoniolithon, Lithophyllum, Tenarea, and Porolithon; the coralliths are Pavona varians (Verrill) and Porites lutea (Milne-Edwards and Haime). Muri Lagoon is the only area on Rarotonga's reef flat that is sheltered by reef islands from ocean waves. The tidal currents, which are predominantly unidirectional in Muri Lagoon, are concentrated by the reef islands into channels through which sand and gravel sediment is regularly transported. However, these prevailing currents do not normally roll the rhodoliths and coralliths. The results of field experiments on the pick-up velocity of the various types of spheroidal structure, combined with observations on growth histories of massive coralliths as revealed by the non-concentric nature of skeletal density banding, indicate that the rhodoliths and coralliths may remain static for periods up to several months yet maintain a complete envelope of living tissue. This downward survival may depend on the strong currents. Not only is the water flushing through the upper millimetre or so of the sediment substrate, but it is also capable of moving the sand and gravel grains which laterally support the rhodoliths and coralliths so that no one point of a spheroidal structure is in direct contact with the substrate for a fatal length of time. Massive rhodoliths have a high preservation potential as discrete spheroidal structures; in contrast, branching rhodoliths and coralliths are prone to fragmentation, and massive coralliths grow into stable microatolls. We conclude that a similar assemblage of rhodoliths, coralliths and microatolls in the fossil record may be indicative of the former existence of contemporary reef flat islands.

  20. sand_point.grd

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC builds and distributes high-resolution, coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to...

  1. Northern Mariana Islands Marine Monitoring Team Reef Flat Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Commonwealth of the Northern Mariana Islands' (CNMI) interagency marine monitoring team conducts surveys on reef flat areas on the islands of Saipan, Tinian and...

  2. Northern fur seal pup weights, Pribilof Islands, Alaska, 1957-present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This database contains northern fur seal pup mass and length data by date, island, rookery and sex on the Pribilof Islands, Alaska, collected between 1957-2012. Mass...

  3. Bituminous sands : tax issues

    Energy Technology Data Exchange (ETDEWEB)

    Patel, B. [PricewaterhouseCoopers LLP, Calgary, AB (Canada)

    2004-07-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs.

  4. Seafloor Backscatter Image of North of Santa Rosa Island, Channel Islands National Marine Sanctuary (8m resolution tif)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter of the seafloor south of Santa Rosa Island in Channel Islands National Marine Sanctuary. It was acquired...

  5. CRED 5 m Gridded bathymetry of Howland Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Howland Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  6. Bathymetry 1M Grid of St. Croix (Buck Island), US Virgin Islands 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Grid with 1 meter cell size representing the bathymetry of the north shore of St. Croix (Buck Island), US Virgin Islands. NOAA's...

  7. Bathymetry 1M GRID of St. Croix (Buck Island), US Virgin Islands, 2004, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Grid with 1 meter cell size representing the bathymetry of the north shore of Buck Island St. Croix, US Virgin Islands. NOAA's...

  8. CRED 20 m Gridded bathymetry of Jarvis Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (20 m cell size) bathymetry of the shelf and slope environments of Jarvis Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  9. CRED 5 m Gridded bathymetry of Jarvis Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Jarvis Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  10. CRED 5 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom coverage...

  11. CRED 5 m Gridded bathymetry of Howland Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Howland Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  12. CRED 40 m Gridded bathymetry of Howland Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Howland Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  13. CRED 40 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  14. CRED 40 m Gridded bathymetry of Howland Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Howland Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  15. CRED 40 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  16. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team...

  17. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geotiff represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography...

  18. NOAA ESRI Geotiff- 1m Bathymetry of St. Croix (Buck Island), US Virgin Islands, 2004, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Geotiff with 1 meter cell size representing the bathymetry of the north shore of Buck Island St. Croix, US Virgin Islands.NOAA's...

  19. 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.

  20. OCEAN THERMAL ENERGY CONVERSION (OTEC) POWER PLANT AND IT???S BY PRODUCTS YIELD FOR SMALL ISLANDS IN INDONESIA SEA WATER

    OpenAIRE

    Siahaya, Yusuf; Salam, Lydia

    2010-01-01

    Small islands in Indonesia sea water are current heavily dependent of fossil fuels. Environmental concerns at global, regional and local levels, past and recent price hikes in the price of oil among others, have been drives behind a regional wide interest in renewable energy technologies. One of the renewable energy resources is the he temperature difference between the upper layer of warm sea water and the bottom layer of cold sea water. As long as the temperature between the ...