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Sample records for island southern chile

  1. Glacier fluctuations during the last 400 years at Mount San Lorenzo and Santa Ines Island, southern Chile

    NASA Astrophysics Data System (ADS)

    Aravena, J.; Luckman, B. H.

    2007-12-01

    We examine the local glacier fluctuations for the last 400 years in two mountain areas of the western coast of southernmost South America, Mount San Lorenzo and Santa Ines Island, using dendroglaciologic, geomorphologic and historical evidence. Mount San Lorenzo moraines span between 1636 and 1927 with periods of more frequent occurrence of glacial advances for the years 1670, 1770, 1870 and 1910. Santa Ines glacial advances are less numerous than in Mount San Lorenzo with well defined, clearly separated frontal moraines. The moraines were colonized by Nothofagus betuloides and Nothofagus antarctica two species with clear and well-preserved tree rings and the total age of the sampled trees was more precisely estimated. Dated moraines cover the last 300 years with evidence for advances during late 1600s, around 1800, 1860, 1910, 1930 and 1960. Further work is needed in dendroglaciological dating, geomorphologic surveying, and better understanding of local glacial dynamics for several glaciers to obtain a regional history of the glacier fluctuations of the southern Andes.

  2. Calbuco Volcano Erupts in Southern Chile

    NASA Image and Video Library

    2015-04-24

    Calbuco Volcano in southern Chile has erupted for the first time since 1972, with the last major eruption occurring in 1961 that sent ash columns 12-15 kilometers high. This image was taken by the Suomi NPP satellite's VIIRS instrument in a high resolution infrared channel around 0515Z on April 23, 2015. Credit: NOAA/NASA/NPP/VIIRS

  3. Familial chondrocalcinosis in the Chiloe Islands, Chile.

    PubMed Central

    Reginato, A J; Hollander, J L; Martinez, V; Valenzuela, F; Schiapachasse, V; Covarrubias, E; Jacobelli, S; Arinoviche, R; Silcox, D; Ruiz, F

    1975-01-01

    Studies about chondrocalcinosis in the Chiloe Islands (Chile) showed the high frequency of the disease there and how most of it is aggregated in a few highly involved families. Pedigrees and the high degree of consanguinity among parents of index cases pointed to a recessive inheritance. The presence of common Caucasian anthropological features of genetic value in the patients and the lack of Indian mixture in three of the involved families, documented back to 1600, suggest a Caucasian origin of the mutation. Biochemical studies of the patients' synovial fluid showed a significant rise in pyrophosphate concentration. Calcium, phosphorus, and alkaline phosphatase concentrations were not different from a control group. PMID:168817

  4. Epidemiology of Vibrio parahaemolyticus Outbreaks, Southern Chile

    PubMed Central

    Harth, Erika; Matsuda, Luis; Hernández, Cristina; Rioseco, Maria L.; Romero, Jaime; González-Escalona, Narjol; Martínez-Urtaza, Jaime

    2009-01-01

    Disease outbreaks caused by Vibrio parahaemolyticus in Puerto Montt, Chile, began in 2004 and reached a peak in 2005 at 3,600 clinical cases. Until 2006, every analyzed case was caused by the serovar O3:K6 pandemic strain. In the summer of 2007, only 475 cases were reported; 73% corresponded to the pandemic strain. This decrease was associated with a change in serotype of many pandemic isolates to O3:K59 and the emergence of new clinical strains. One of these strains, associated with 11% of the cases, was genotypically different from the pandemic strain but contained genes that were identical to those found on its pathogenicity island. These findings suggest that pathogenicity-related genes were laterally transferred from the pandemic strain to one of the different V. parahaemolyticus groups comprising the diverse and shifting bacterial population in shellfish in this region. PMID:19193258

  5. Calbuco Volcano Erupts in Southern Chile

    NASA Image and Video Library

    2017-09-28

    Calbuco Volcano in southern Chile has erupted for the first time since 1972, with the last major eruption occurring in 1961 that sent ash columns 12-15 kilometers high. This image was taken by the Suomi NPP satellite's VIIRS instrument in a high resolution infrared channel around 0515Z on April 23, 2015. Credit: NOAA/NASA/NPP/VIIRS Credit: NOAA/NASA GOES Project NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  6. Detection of dengue virus type 4 in Easter Island, Chile.

    PubMed

    Fernández, J; Vera, L; Tognarelli, J; Fasce, R; Araya, P; Villagra, E; Roos, O; Mora, J

    2011-10-01

    We report the detection of dengue virus type 4 (DENV-4) for the first time in Easter Island, Chile. The virus was detected in serum samples of two patients treated at the Hospital in Easter Island. The two samples were IgM positive, and the infection was confirmed by RT-PCR and genetic sequencing; viral isolation was possible with one of them. The Easter Island isolates were most closely related to genotype II of dengue type 4.

  7. The last glacial-Holocene transition in southern Chile.

    PubMed

    Bennett, K D; Haberle, S G; Lumley, S H

    2000-10-13

    Warming at the last glacial termination in the North Atlantic region was interrupted by a period of renewed glacial activity during the Younger Dryas chronozone (YDC). The underlying mechanism of this cooling remains elusive, but hypotheses turn on whether it was a global or a North Atlantic phenomenon. Chronological, sedimentological, and palaeoecological records from sediments of small lakes in oceanic southern Chile demonstrate that there was no YDC cooling in southern Chile. It is therefore likely that there was little or no cooling in southern Pacific surface waters and hence that YDC cooling in the North Atlantic was a regional, rather than global, phenomenon.

  8. Counternarcotic Efforts in the Southern Cone: Chile

    DTIC Science & Technology

    1990-06-30

    Direccion General del Territorio Maritimo (DGTM)....................17 5. General Staff of the Armed Forces. . . . 18 6. The Ministry of Justice...narcotic law enforcement activities in Chile. But they are not the only ones. Customs, the Direccion General del Territorio Maritimo (DGTM) -the Chilean...closely with Carabineros and in some isolated border posts Carabineros takes on the function of Custom Agent. 4. Direccion General del Territorio Maritimo

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

    NASA Astrophysics Data System (ADS)

    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

  10. mtDNA microevolution in Southern Chile's archipelagos.

    PubMed

    García, Federico; Moraga, Mauricio; Vera, Soledad; Henríquez, Hugo; Llop, Elena; Aspillaga, Eugenio; Rothhammer, Francisco

    2006-03-01

    The genetic variability of four predominantly Indian populations of southern Chile's archipelagos was examined by determining the frequencies of four mitochondrial DNA haplogroups that characterize the American Indian populations. Over 90% of the individuals analyzed presented Native American mtDNA haplogroups. By means of an unweighted group pair method with arithmetic mean (UPGMA) dendrogram, a principal component analysis (PCA) derived from a distance matrix of mtDNA, and the exact test of population differentiation, we are able to prove the existence of a North-South cline. The populations in the northern part of the archipelagos are genetically similar to the Huilliche tribe, while the groups from the South are most closely related to the Fueguino tribe from the extreme South of Chile, and secondarily to the Pehuenche and Mapuche, who are found to the North and East of Chiloé archipelago. These results are consistent with a colonization of the southern archipelagos from Tierra del Fuego. We evaluate the evolutionary relationships of the population of the Chiloé area to groups from other geographic areas of Chile, using analysis of molecular variance (AMOVA). Three Amerindian clusters are identified: one formed by the Aymará and Atacameño, a second by the Huilliche, and a third including the Mapuche, Pehuenche, and Fueguino tribes, and the population inhabiting the South of the Chiloé arcipelago. These groups exhibit a North-South gradient in the frequency of haplogroup B, confirmed by F(ST) tests. (c) 2005 Wiley-Liss, Inc.

  11. Chile.

    PubMed

    1988-09-01

    Chile is a long (2650 miles), narrow (250 miles at widest point) country sandwiched between the Andes mountains and the Pacific. The northern desert is rich in copper and nitrates; the temperate middle region is agricultural and supports the major cities, including Santiago, the capital, and the port of Valparaiso; and the southern region is a cold and damp area of forests, grasslands, lakes, and fjords. The country is divided into 12 administrative regions. Chile's population of 12.5 million are mainly of Spanish or Indian descent or mestizos. Literacy is 92.3%, and the national language is Spanish. Infant mortality is 18.1/1000, and life expectancy is 68.2 years. 82% of the people are urban, and most are Roman Catholics. Chile was settled by the Spanish in 1541 and attached to the Viceroyalty of Peru. Independence was won in 1818 under the leadership of Bernardo O'Higgins. In the 1880s Chile extended its sovereignty over the Strait of Magellan in the south and areas of southern Peru and Bolivia in the north. An officially parliamentary government, elected by universal suffrage, drifted into oligarchy and finally into a military dictatorship under Carlos Ibanez in 1924. Constitutional government was restored in 1932. The Christian Democratic government of Eduardo Frei (1964-70) inaugurated major reforms, including land redistribution, education, and far-reaching social and economic policies. A Marxist government under Salvador Allende lasted from 1970 to 1973 when the present military government of General Pinochet Ugarte took power, overthrew Allende, abolished the Congress, and banned political parties. It has moved the country in the direction of a free market economy but at the cost of systematic violations of human rights. A new constitution was promulgated in 1981, and congressional elections have been scheduled for October, 1989. A "National Accord for Transition to Full Democracy" was mediated by the Catholic Church in 1985. The social reforms of the

  12. Structural Responses to the Chile Ridge Subduction, Southern South America

    NASA Astrophysics Data System (ADS)

    Rodriguez, E. E.; Russo, R. M.; Mocanu, V. I.; Gallego, A.; Murdie, R.; Comte, D.

    2015-12-01

    The Nazca-Antarctic plate boundary, the Chile spreading ridge, subducts beneath South America, forming the northward-migrating Chile Triple Junction (CTJ), now at ~46.5°S, where an actively spreading segment is currently in the Nazca trench. Ridge subduction is associated with diachronously developed variable structure and magmatism of overriding South America. To assess the effects of ridge subduction, we deployed a network of 39 broadband seismometers in southern Chile between 43 - 49°S and 71 - 76°W from Dec. 2004 - Feb. 2007, recording 102 earthquakes suitable for receiver function analyses, i.e., M > 5.9, of various backazimuths, and at epicentral distances of 30 - 90°. The network encompassed onland portions of the current triple junction and ridge subduction, areas to the south of the CTJ where ridge segments subducted during the last 6 m.y., and regions north of the CTJ not yet affected by ridge subduction, allowing the assessment of the effects of ridge subduction on crustal structure of overriding South America. We constructed 551 teleseismic receiver functions to estimate crustal thicknesses, H, and average compressional to shear wave velocity ratios, Vp/Vs = k, using the iterative time deconvolution method of Ligorria and Ammon (1999). H and k were calculated using the grid search method of Zhu and Kanamori (2000). Beneath stations closest to the trench, where the Nazca plate subducts, we found Moho depths between 28 and 55 km, thickening northward. At the locus of current ridge subduction, in the Taitao Pennisula, thinner crust ranges from 27 - 36 km. H is 36-38 km where the Antarctic plate subducts and the Chile ridge recently subducted. The direct effect of the subducting ridge on South America can be seen in H differences between forearc regions that have sustained ridge subduction versus those that have not. South American forearc crust above the subducted Nazca plate is as much as 28 km thicker than forearc crust recently affected by ridge

  13. Dengue-1 virus isolation during first dengue fever outbreak on Easter Island, Chile.

    PubMed

    Perret, Cecilia; Abarca, Katia; Ovalle, Jimena; Ferrer, Pablo; Godoy, Paula; Olea, Andrea; Aguilera, Ximena; Ferrés, Marcela

    2003-11-01

    Dengue virus was detected for the first time in Chile, in an outbreak of dengue fever on Easter Island. The virus was isolated in tissue culture and characterized by reverse transcription-polymerase chain reaction as being dengue type 1.

  14. Endohelminth parasites from salmonids in intensive culture from southern Chile.

    PubMed

    Torres, P; Quintanilla, J C; Rozas, M; Miranda, P; Ibarra, R; San Martín, M F; Raddatz, B; Wolter, M; Villegas, A; Canobra, C; Hausdorf, M; Silva, R

    2010-06-01

    A total of 228 salmonids (90 Oncorhynchus mykiss, 48 Oncorhynchus kisutch, and 90 Salmo salar) from 8 intensive aquaculture centers in the south of Chile were examined for endohelminths parasites between December 2008 and May 2009. The body cavities of 2 O. mykiss were infected by Diphyllobothrium sp. plerocercoids (prevalence: 6.7%, mean intensity: 1.0, mean abundance: 0.07) from the Lake Tarahuin hatchery on the south of Chiloé Island. Also, tetraphyllidean plerocercoids (prevalence: 3.3%, mean intensity: 1, mean abundance: 0.03) and fourth-stage larvae of Hysterothylacium aduncum (prevalence: 6.7%, mean intensity: 1, mean abundance 0.07) were observed in O. kisutch from a marine hatchery in Chiloé. The occurrences of Diphyllobothrium sp. in a lake and a tetraphyllidean plerocercoid from marine cultured salmonid in Chiloé are reported for first time. No muscular infection by helminths was recorded in the fish examined.

  15. Hantavirus Pulmonary Syndrome , Southern Chile, 1995–2012

    PubMed Central

    Riquelme, Raúl; Rioseco, María Luisa; Bastidas, Lorena; Trincado, Daniela; Riquelme, Mauricio; Loyola, Hugo; Valdivieso, Francisca

    2015-01-01

    Hantavirus is endemic to the Region de Los Lagos in southern Chile; its incidence is 8.5 times higher in the communes of the Andean area than in the rest of the region. We analyzed the epidemiologic aspects of the 103 cases diagnosed by serology and the clinical aspects of 80 hospitalized patients during 1995–2012. Cases in this region clearly predominated during winter, whereas in the rest of the country, they occur mostly during summer. Mild, moderate, and severe disease was observed, and the case-fatality rate was 32%. Shock caused death in 75% of those cases; high respiratory frequency and elevated creatinine plasma level were independent factors associated with death. Early clinical suspicion, especially in rural areas, should prompt urgent transfer to a hospital with an intensive care unit and might help decrease the high case-fatality rate. PMID:25816116

  16. The Aysen (Southern Chile) 2007 Seismic Swarm: Volcanic or Tectonic Origin?

    NASA Astrophysics Data System (ADS)

    Comte, D.; Gallego, A.; Russo, R.; Mocanu, V.; Murdie, R.; Vandecar, J.

    2007-05-01

    The Aysen seismic swarm began January 23, 2007, with a magnitude 5.2 (USGS) earthquake and, after an apparent decrease in activity, continued with a magnitude 5.6 event on February 26. The swarm is characterized by numerous felt earthquakes of small to moderate magnitude, located at crustal depths beneath the Aysen Canal, a prominent fiord of the Chilean littoral. The region is characterized by the subduction of an active oceanic spreading ridge: the Chile Ridge, the divergent Nazca-Antarctic plate boundary, is currently subducting beneath continental South America along the Chile Trench at approximately 46.5°S, forming a plate triple junction in the vicinity of the Taitao Peninsula, somewhat south and west of the swarm. Also, the Liquine-Ofqui dextral strike- slip fault traverses the Aysen Canal in the vicinity of the swarm. This fault has been interpreted as a 1000 km long dextral intra-arc strike-slip fault zone, consisting of two major strands which extend north from the Chile Margin triple junction. The Liquiñe-Ofqui system is marked by several pull-apart basins along its trace through the area. Seismic activity along the Liquiñe-Ofqui fault zone has been poorly studied to date, largely because teleseismic events clearly related to the fault have been few, and southern hemisphere seismic stations are lacking. However, we deployed a dense temporary broad-band seismic network both onland and on the islands in the Aysen region, which allowed us to capture the initial phases of the swarm on some 20 stations, and to determine the background seismicity patterns in this area for the two years preceding the swarm. The swarm could be caused by several processes: the spatial and depth distribution of the events suggests that they are well correlated with reactivation of the southern end of the Liquiñe-Ofqui fault, as defined by geologic studies and onshore gravity data collected in southern Chile. The swarm may be related to formation of new volcanic center between

  17. Anisakid parasites in commercial hake ceviche in southern Chile.

    PubMed

    Torres-Frenzel, Pablo; Torres, Patricio

    2014-07-01

    The objective of this research was to determine the occurrence of anisakid nematode larvae in hake ceviche sold in restaurants in Valdivia (39°48'S, 73°14'W) and Niebla (39°49'S, 73°22'W), Chile. Between August and November 2012, 78 portions of ceviche were collected (6 from each of the 13 restaurants that sell this product). Each portion was weighed and divided into approximately 30-g samples, which were placed in petri dishes with 0.15 M NaCl. All samples were manually shredded and then examined with a stereomicroscope. Muscles of 41 southern hake (Merluccius australis), a fish sold fresh in Valdivia, also were examined by candling to determine the presence of anisakid larvae. The presence of Pseudoterranova larvae in ceviche sold in Chile was identified for the first time. The pH of ceviche ranges from 4.1 to 4.8, which favors the presence of viable anisakid larvae that tolerate the acid pH similar to that found in the stomach of their mammalian host. No significant differences (P > 0.05) in the prevalence, mean abundance, and mean density of anisakid larvae in ceviche were found between localities. Larvae were detected in ceviche from 3 of 6 restaurants in Valdivia and 4 of 7 restaurants in Niebla. Of the 78 examined portions of ceviche, 21.8% had larvae. The prevalence of viable larvae was 16.7 and 7.1% in the examined portions from Valdivia and Niebla, respectively. In the 41 hake muscle samples from Valdivia, the prevalence (4.9%), mean abundance (0.1), and mean density (0.03) was the same for Pseudoterranova and Anisakis larvae. No inspection processes or pretreatments are currently in place for raw fish to achieve safe conditions for ceviche in restaurants from Valdivia and Niebla.

  18. Tephrochronology of the southernmost Andean Southern Volcanic Zone, Chile

    NASA Astrophysics Data System (ADS)

    Weller, D. J.; Miranda, C. G.; Moreno, P. I.; Villa-Martínez, R.; Stern, C. R.

    2015-12-01

    Correlations among and identification of the source volcanoes for over 60 Late Glacial and Holocene tephras preserved in eight lacustrine sediment cores taken from small lakes near Coyhaique, Chile (46° S), were made based on the stratigraphic position of the tephra in the cores, lithostratigraphic data (tephra layer thickness and grain size), and tephra petrochemistry (glass color and morphology, phenocryst phases, and bulk-tephra trace element contents determined by ICP-MS). The cores preserve a record of explosive eruptions, since ˜17,800 calibrated years before present (cal years BP), of the volcanoes of the southernmost Andean Southern Volcanic Zone (SSVZ). The suggested source volcanoes for 55 of these tephras include Hudson (32 events), Mentolat (10 events), and either Macá or Cay or some of the many minor monogenetic eruptive centers (MECs; 13 events) in the area. Only four of these eruptions had been previously identified in tephra outcrops in the region, indicating the value of lake cores for identifying smaller eruptions in tephrochronologic studies. The tephra records preserved in these lake cores, combined with those in marine cores, which extend these records back to 20,000 cal years BP, prior to the Last Glacial Maximum, suggest that no significant temporal change in the frequency of explosive eruptions was associated with deglaciation. Over this time period, Hudson volcano, one of the largest and longest lived volcanoes in the Southern Andes, has had >55 eruptions (four of them were very large) and has produced >45 km3 of pyroclastic material, making it also one of the most active volcanoes in the SVZ in terms of both frequency and volume of explosive eruptions.

  19. Ice volumetric changes on active volcanoes in southern Chile

    NASA Astrophysics Data System (ADS)

    Rivera, Andrés; Bown, Francisca; Mella, Ronald; Wendt, Jens; Casassa, Gino; Acuña, César; Rignot, Eric; Clavero, Jorge; Brock, Benjamin

    Most of the glaciers in southern Chile have been retreating and shrinking during recent decades in response to atmospheric warming and decrease in precipitation. However, some glacier fluctuations are directly associated with the effusive and geothermal activity of ice-covered active volcanoes widely distributed in the region. The aim of this paper is to study the ice volumetric changes by comparing several topographic datasets. A maximum mean ice thinning rate of 0.81 ± 0.45 m a-1 was observed on the ash/debris-covered ablation area of Volcán Villarrica between 1961 and 2004, whilst on Volcán Mocho the signal-to-noise ratio was too small to yield any conclusion. An area reduction of 0.036 ± 0.019 km2 a-1 since 1976 was obtained on Glaciar Mocho, while on Volcán Villarrica the area change was -0.090 ± 0.034 km2 a-1 between 1976 and 2005. Glaciers on active volcanoes are therefore shrinking, mainly in response to climatic driving factors. However, volcanic activity is affecting glaciers in two opposite ways: ash/debris advection is helping to reduce surface ablation at lower reaches by insulating the ice from solar radiation, while geothermal activity is probably enhancing melting and water production at the bedrock, resulting in negative ice-elevation changes.

  20. Postglacial formation and dynamics of North Patagonian Rainforest in the Chonos Archipelago, Southern Chile

    NASA Astrophysics Data System (ADS)

    Haberle, S. G.; Bennett, K. D.

    2004-12-01

    Pollen analysis of continuous sediment cores from two lakes in the northern Chonos Archipelago (44°S) in southern Chile shows a complete postglacial record of vegetation change. The fossil records indicate that deglaciation was complete in the northern Chonos by at least 13,600 14C yr BP. Ericaceous heath and grassland persisted for more than 600 years after deglaciation under the influence of dry/cold climates and frequent burning. Nothofagus- Pilgerodendron- Podocarpus forest, with modern analogues in the southern Chonos Archipelago, was established across the northern islands by 12,400 14C yr BP under increasingly warm and wet climates. There is no evidence for a return to cooler climates during the Younger Dryas chronozone. The rise of Tepualia stipularis and Weinmannia trichosperma as important forest components between 10,600 and 6000 14C yr BP may be associated with climates that were warmer than present. The collapse of Pilgerodendron communities during this time may have been triggered by a combination of factors related to disturbance frequency including tephra deposition events, fire and climate change. After 6000 14C yr BP Pilgerodendron recovers and Nothofagus-Pilgerodendron-Tepualia forest persists until the present. European logging and burning activity may have increased the susceptibility of North Patagonian Rainforest to invasion by introduced species and to future collapse of the long-lived Pilgerodendron communities.

  1. Age and petrogenesis of the Sarmiento ophiolite complex of southern Chile

    NASA Astrophysics Data System (ADS)

    Stern, C. R.; Mukasa, S. B.; Fuenzalida P., R.

    1992-08-01

    Zircon fractions separated from fine-grained plagiogranites, interpreted to be cogenetic with the mafic rocks of the Sarmiento ophiolite complex in southern Chile, yield slightly to grossly discordant age patterns for which the lower concordia intercept U-Pb ages of 140.7 ± 0.7 Ma (Lolos Fjord) and 137.1 ± 0.6 Ma (Encuentro Fjord) are well constrained. These dates are interpreted as formation ages for the northern portion of the igneous floor of the Rocas Verdes basin, and they are younger than the age of 150 Ma determined for a more southern portion of the floor of this basin on South Georgia Island. Coarse-grained trondjemites within the gabbro units of the Sarmiento complex yield a lower concordia intercept U-Pb age of 147 ± 10 Ma and a poorly defined upper intercept reflecting an inherited zircon component, possibly of Proterozoic age. These rocks are interpreted as remobilized fragments of country rocks entrapped within the essentially mantle-derived rocks of the ophiolite complex.

  2. Monitoring of geological activity on astronomical sites of the Canary Islands, Hawaii, and Chile

    NASA Astrophysics Data System (ADS)

    Eff-Darwich, Antonio; Garcia-Lorenzo, Begoña; Rodriguez-Losada, Jose A.; Hernández-Gutiérrez, Luis E.; de la Nuez, Julio; Romero-Ruiz, Maria C.

    2009-09-01

    Future large and extremely large ground-based telescopes will demand stable geological settings.Remote sensing could be an unvaluable tool to analyse the impact of geological activity at selected astronomical sites, namely the observatories of El Teide (Tenerife, Canary Islands), Roque de los Muchachos (La Palma, Canary Islands), Mauna Kea (Hawaii) and Paranal (Chile; the candidate site of Cerro Ventarrones, Chile). In this sense, the extent of lava flows, eruptive clouds or ground deformation associated to seismic and/or volcanic activity could be analysed and characterised through remote sensing.

  3. Dense Local Seismic Network at Villarrica Volcano (Southern Chile)

    NASA Astrophysics Data System (ADS)

    Mora-Stock, C.; Thorwart, M.; Dzieran, L.; Rabbel, W.

    2013-12-01

    Villarrica volcano is one of the most active volcanoes in the Southern Andes. It has been presenting constant fumarole activity and seismicity since its last eruption in 1984-85. A local network was installed at Villarrica volcano (Southern Chile) during the first two weeks of March, 2012. In total, 75 DSS-Cube short-period stations (30 3-Component, 45 1-Component) were deployed at and around the volcano area, covering approx. 63 km x 55 km. The average station spacing is 1.5 km for stations inside the perimeter of the volcanic edifice, and 5km outside this perimeter. The network recorded ca. 94 volcano tectonic (VT) events located SSW, SSE and North of the crater, with clear P- and S-wave arrivals. Many others, ca.73 events, could be classified as 'hybrid' events (HB), which present high frequencies at the beginning of the signal, and a sharp and notorious S-wave at the crater stations, but a strong scattering, lower frequency content, and elongated coda on the stations along the volcanic edifice. This strong scattering effect is probably caused by the heterogeneous ash layers on the edifice structure. Few long period events (LP), with main frequencies between 2-4 Hz, were observed. From the tectonic regional events, three sets of events can be distinguished. One coming from the southern end of the focal plane of the Maule earthquake (2010), with S-P wave travel time difference of ca. 30 s or more. Another closer group with S-P wave travel time difference between 10 s and 20 s, and the last group with S-P wave travel time difference of 10 s or less. A cross-correlation analysis to the travel times of the regional events and a teleseismic event from Argentina was applied in order to determine the average velocity structure of the volcano, and obtained an average P-wave velocity of 3.6 km/s for the volcanic edifice inside a radius of 6.5 km, and 4.1 km/s for the surrounding area outside this radius. This model serves as a starting point for local earthquake

  4. Dengue-1 Virus Isolation during First Dengue Fever Outbreak on Easter Island, Chile

    PubMed Central

    Abarca, Katia; Ovalle, Jimena; Ferrer, Pablo; Godoy, Paula; Olea, Andrea; Aguilera, Ximena; Ferrés, Marcela

    2003-01-01

    Dengue virus was detected for the first time in Chile, in an outbreak of dengue fever on Easter Island. The virus was isolated in tissue culture and characterized by reverse transcription–polymerase chain reaction as being dengue type 1. PMID:14718094

  5. [Detection of flavivirus in mosquitoes (Diptera: Culicidae) from Easter Island-Chile].

    PubMed

    Collao, Ximena; Prado, Lorena; González, Christian; Vásquez, Ana; Araki, Romina; Henríquez, Tuki; Peña, Cindy M

    2015-02-01

    Flaviviruses are arthropod-borne viruses, mainly by mosquitoes of the genera Aedes and Culex (Culicidae) that are detected in tropical and subtropical areas. Main flaviviruses of public health importance are: dengue, West Nile virus, yellow fever, among others. In continental Chile, flaviviruses has not been detected. However, there are indigenous cases of dengue detected in Easter Island since 2002, as the presence of its vector Aedes aegypti. The aim of this study was: To determine diversity of flavivirus mosquitoes present in Easter Island. Thirty pools of mosquitoes collected in Hanga Roa were analyzed; a RT-PCR nested flavivirus was performed. Thirteen positive samples were detected and the amplification products were sequenced, identifying two specific flavivirus Insect, the Cell fusing agent virus and other related viruses Kamiti River. This is the first study in Chile showed the presence of flavivirus in vectors in Easter Island.

  6. Carbon stocks of an old-growth forest and an anthropogenic peatland in southern Chile

    NASA Astrophysics Data System (ADS)

    Perez-Quezada, Jorge; Brito, Carla; Cabezas, Julian; Salvo, Patricia; Lemunao, Pedro; Flores, Ernesto; Valdés, Ariel; Fuentes, Juan Pablo; Galleguillos, Mauricio; Pérez, Cecilia

    2015-04-01

    The distribution of carbon in the different ecosystem stocks may change with direct human perturbation or climate change. We present a detailed description of the carbon stocks of an old-growth forest and an anthropogenic peatland (i.e., created by flooding, as a consequence of forest fires or logging). The study area was located in a private reserve in the Chiloé Island, southern Chile (41° 52' S, 73° 40' W). Sampling was done on plots separated 60 m from each other, in areas of approximately 30 ha for each ecosystem type. Total C was 1523 ± 117 Mg ha-1 in the forest and 130 ± 13.8 Mg ha-1 in the peatland, with 69.7% and 91.7% of this found belowground, respectively. In the forest, the necromass stock composed by logs and snags was high (183 Mg C ha-1), compared with the live-tree stock (264 Mg C ha-1) and with the C stored in the understory vegetation (14 Mg C ha-1). In the peatland, most of the C was stored in the most decomposed layer of peat, deeper in the ground. Because the anthropogenic peatland is experiencing a secondary succession, there is great potential to sequester back the C lost due to the perturbation. However, in most of the area where these ecosystems are found, the moss is being harvested for horticultural purposes.

  7. Low frequency earthquakes below southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Bostock, M. G.; Royer, A. A.; Hearn, E. H.; Peacock, S. M.

    2012-11-01

    The nature and distribution of low frequency earthquakes (LFEs) in subduction zones provide insight into plate boundary deformation downdip of the locked seismogenic zone. We employ network autocorrelation detection to identify LFE families beneath southern Vancouver Island and environs. An initial suite of 5775 LFEs detected in 2004 and 2005 at a select set of 7 stations is grouped into 140 families using waveform cluster analysis. These families are used as templates within an iterative network cross correlation scheme to detect LFEs across different tremor episodes, incorporate new stations, and improve LFE template signal-to-noise ratio. As in southwest Japan, representative LFE locations define a relatively tight, dipping surface several km above the locus of intraslab seismicity, within a prominent, dipping low-velocity zone (LVZ). LFE polarizations for near-vertical source-receiver geometries possess a remarkably uniform dipolar signature indicative of point-source, double-couple excitation. Focal mechanisms determined fromP-wave first motions are characterized by a combination of strike-slip and thrust faulting. We suggest that LFEs and regular intraslab seismicity occur in distinct structural and stress regimes. The LVZ, inferred to represent weak, overpressured, porous and mylonitized metabasalts of oceanic crustal Layer 2, separates LFEs manifesting deformation within a plate boundary shear zone from intraslab earthquakes generated by tensional stresses and dehydration embrittlement within a more competent lower oceanic crustal Layer 3 and underlying mantle.

  8. Transboundary protected area proposals along the Southern Andes of Chile and Argentina: Status of current efforts

    Treesearch

    Peter Keller

    2007-01-01

    An evolving network of protected areas along the southern Andes of Chile and Argentina-the heart of Patagonia-are in various stages of evaluation and potential Transboundary Protected Area designations. This paper examines three such efforts. The first proposal is the North Andean-Patagonia Regional Eco-Corridor, which was the subject of a recent bilateral meeting...

  9. A New Click Beetle Genus from Southern Chile: Llanquihue (Coleoptera, Elateridae, Elaterinae, Pomachiliini)

    PubMed Central

    Arias, Elizabeth T.

    2008-01-01

    Llanquihue, a new genus of Elateridae from Southern Chile, is here described and illustrated with 2 species: Llanquihue vittipennis (Candèze) new comb., and L. carlota sp. nov. The genus Llanquihue belongs to the subfamily Elaterinae and to the tribe Pomachiliini. PMID:20233094

  10. Marine Biodiversity in Juan Fernández and Desventuradas Islands, Chile: Global Endemism Hotspots.

    PubMed

    Friedlander, Alan M; Ballesteros, Enric; Caselle, Jennifer E; Gaymer, Carlos F; Palma, Alvaro T; Petit, Ignacio; Varas, Eduardo; Muñoz Wilson, Alex; Sala, Enric

    2016-01-01

    The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures.

  11. Marine Biodiversity in Juan Fernández and Desventuradas Islands, Chile: Global Endemism Hotspots

    PubMed Central

    Friedlander, Alan M.; Ballesteros, Enric; Caselle, Jennifer E.; Gaymer, Carlos F.; Palma, Alvaro T.; Petit, Ignacio; Varas, Eduardo; Muñoz Wilson, Alex; Sala, Enric

    2016-01-01

    The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures. PMID:26734732

  12. Earthshots: Satellite images of environmental change – Selkirk Island, Chile

    USGS Publications Warehouse

    ,

    2013-01-01

    How did these Karman vortices develop? On that day, the wind was carrying northward a layer of stratocumulus clouds (flat-bottomed puffballs). The mile-high island caused this cloud layer to slow about the island, while remaining fast farther out on either side. So on each “wing,” left and right, the air started rotating toward the inside—clockwise on the left, counter-clockwise on the right. The rotational momentum made each side swirl in on itself. The whorl-cores were clear because the swirling pulled dry, clear air (from above or below) into the wet layer, a bit like the funnel formed when you stir up a pitcher of orange juice. These clear, spinning pockets trailed off down the “street” from the island like soap bubbles from a toy wand—drifting downwind, weakening, filling with clouds, and breaking up.

  13. Complete nucleotide sequence analysis of a Dengue-1 virus isolated on Easter Island, Chile.

    PubMed

    Cáceres, C; Yung, V; Araya, P; Tognarelli, J; Villagra, E; Vera, L; Fernández, J

    2008-01-01

    Dengue-1 viruses responsible for the dengue fever outbreak in Easter Island in 2002 were isolated from acute-phase sera of dengue fever patients. In order to analyze the complete genome sequence, we designed primers to amplify contiguous segments across the entire sequence of the viral genome. RT-PCR products obtained were cloned, and complete nucleotide and deduced amino acid sequences were determined. This report constitutes the first complete genetic characterization of a DENV-1 isolate from Chile. Phylogenetic analysis shows that an Easter Island isolate is most closely related to Pacific DENV-1 genotype IV viruses.

  14. A new ant genus from southern Argentina and southern Chile, Patagonomyrmex (Hymenoptera: Formicidae).

    PubMed

    Johnson, Robert A; Moreau, Corrie S

    2016-07-19

    The ant genus Pogonomyrmex (Hymenoptera: Formicidae: Myrmicinae) comprises 71 described species that occur in North America, South America, and Hispaniola, and it is the nominal genus in the recently established tribe Pogonomyrmecini. A molecular phylogeny using 3,647 base pairs from fragments of one mitochondrial gene (cytochrome oxidase I) and five nuclear genes (long-wavelength rhodopsin, elongation factor 1α F1, elongation factor 1α F2, wingless, rudimentary) inferred that Pogonomymrex was not monophyletic. The vast majority of species belonged to a monophyletic clade (Pogonomyrmex sensu stricto), whereas species in the Po. angustus-group formed a second lineage outside of Pogonomyrmex and Hylomyrma, the latter being the only other genus in the tribe. To maintain monophyly of Pogonomyrmex, we create the genus Patagonomyrmex gen. n., which consists of the three angustus-group species (Patagonomyrmex angustus comb. n., Patagonomyrmex laevigatus comb. n., and Patagonomyrmex odoratus comb. n.) that are sister to all other pogonomyrmecines. The genus is restricted to southern Argentina and southern and southcentral Chile. Workers are characterized by: (1) poorly-developed psammophore that consists of short to medium-length hairs scattered over the ventral surface of the head, (2) anterior clypeal margin strongly convex in full-face view, (3) clypeus strongly convex in profile, (4) superior and inferior propodeal spines long, (5) dorsal surface of promesonotum smooth and shiny, lacking rugae or if rugae present, then interrugae strongly granulate-punctate, (6) anteroventral margin of peduncle of the petiole with a small, acuminate spine, and (7) palp formula 5,4. We also provide information on biology, distribution maps, and a key to workers, queens, and males in English and Spanish.

  15. [Prevalence of congenital malformations at birth and associated factors in Easter Island, Chile (1988-1998)].

    PubMed

    Aguila, A; Nazer, J; Cifuentes, L; Mella, P; de la Barra, P; Gutiérrez, D

    2000-02-01

    Consanguinity plays an important role in the genetic etiology of congenital malformations. In Easter Island the degree of consanguinity could be higher than in continental Chile. Therefore the study of the prevalence of congenital malformations in this island seems worthwhile. To study the prevalence of congenital malformations at birth in Easter Island. A review of personal and family features of all children born alive between 1988 and 1998 in the Rapa Nui Hospital of Easter Island. During the study period, 772 newborns were reviewed and 22 were found to have congenital malformations. Among the latter, birth weight fluctuated between 3001 and 4000 g and the male/female ratio was 0.54. No differences in maternal age between children with and without malformations was observed. Heart and circulatory malformations, hemangiomas and Down syndrome were the predominant malformations. The prevalence of congenital malformations at birth in Easter Island is similar to that of continental Chile. No neural tube defects were detected in this sample.

  16. Birth of two volcanic islands in the southern Red Sea

    PubMed Central

    Xu, Wenbin; Ruch, Joël; Jónsson, Sigurjón

    2015-01-01

    Submarine eruptions that lead to the formation of new volcanic islands are rare and far from being fully understood; only a few such eruptions have been witnessed since Surtsey Island emerged to the south of Iceland in the 1960s. Here we report on two new volcanic islands that were formed in the Zubair archipelago of the southern Red Sea in 2011–2013. Using high-resolution optical satellite images, we find that the new islands grew rapidly during their initial eruptive phases and that coastal erosion significantly modified their shapes within months. Satellite radar data indicate that two north–south-oriented dykes, much longer than the small islands might suggest, fed the eruptions. These events occurred contemporaneously with several local earthquake swarms of the type that typically accompany magma intrusions. Earthquake activity has been affecting the southern Red Sea for decades, suggesting the presence of a magmatically active zone that has previously escaped notice. PMID:26010945

  17. Birth of two volcanic islands in the southern Red Sea.

    PubMed

    Xu, Wenbin; Ruch, Joël; Jónsson, Sigurjón

    2015-05-26

    Submarine eruptions that lead to the formation of new volcanic islands are rare and far from being fully understood; only a few such eruptions have been witnessed since Surtsey Island emerged to the south of Iceland in the 1960s. Here we report on two new volcanic islands that were formed in the Zubair archipelago of the southern Red Sea in 2011-2013. Using high-resolution optical satellite images, we find that the new islands grew rapidly during their initial eruptive phases and that coastal erosion significantly modified their shapes within months. Satellite radar data indicate that two north-south-oriented dykes, much longer than the small islands might suggest, fed the eruptions. These events occurred contemporaneously with several local earthquake swarms of the type that typically accompany magma intrusions. Earthquake activity has been affecting the southern Red Sea for decades, suggesting the presence of a magmatically active zone that has previously escaped notice.

  18. Ridge-trench collision in Archean and Post-Archean crustal growth: Evidence from southern Chile

    NASA Technical Reports Server (NTRS)

    Nelson, E. P.; Forsythe, R. D.

    1988-01-01

    The growth of continental crust at convergent plate margins involves both continuous and episodic processes. Ridge-trench collision is one episodic process that can cause significant magmatic and tectonic effects on convergent plate margins. Because the sites of ridge collision (ridge-trench triple junctions) generally migrate along convergent plate boundaries, the effects of ridge collision will be highly diachronous in Andean-type orogenic belts and may not be adequately recognized in the geologic record. The Chile margin triple junction (CMTJ, 46 deg S), where the actively spreading Chile rise is colliding with the sediment-filled Peru-Chile trench, is geometrically and kinematically the simplest modern example of ridge collision. The south Chile margin illustrates the importance of the ridge-collision tectonic setting in crustal evolution at convergent margins. Similarities between ridge-collision features in southern Chile and features of Archean greenstone belts raise the question of the importance of ridge collision in Archean crustal growth. Archean plate tectonic processes were probably different than today; these differences may have affected the nature and importance of ridge collision during Archean crustal growth. In conclusion, it is suggested that smaller plates, greater ridge length, and/or faster spreading all point to the likelihood that ridge collision played a greater role in crustal growth and development of the greenstone-granite terranes during the Archean. However, the effects of modern ridge collision, and the processes involved, are not well enough known to develop specific models for the Archean ridge collison.

  19. Prevalence, hematological findings and genetic diversity of Bartonella spp. in domestic cats from Valdivia, Southern Chile.

    PubMed

    Müller, Ananda; Walker, Romina; Bittencourt, Pedro; Machado, Rosangela Zacarias; Benevenute, Jyan Lucas; DO Amaral, Renan Bressiani; Gonçalves, Luiz Ricardo; André, Marcos Rogério

    2016-12-12

    The present study determined the prevalence, hematological findings and genetic diversity of Bartonella spp. in domestic cats from Valdivia, Southern Chile. A complete blood count and nuoG gene real-time quantitative PCR (qPCR) for Bartonella spp. were performed in 370 blood samples from cats in Valdivia, Southern Chile. nuoG qPCR-positive samples were submitted to conventional PCR for the gltA gene and sequencing for species differentiation and phylogenetic analysis. Alignment of gltA gene was used to calculate the nucleotide diversity, polymorphic level, number of variable sites and average number of nucleotide differences. Bartonella DNA prevalence in cats was 18·1% (67/370). Twenty-nine samples were sequenced with 62·0% (18/29) identified as Bartonella henselae, 34·4% (10/29) as Bartonella clarridgeiae, and 3·4% (1/29) as Bartonella koehlerae. Bartonella-positive cats had low DNA bacterial loads and their hematological parameters varied minimally. Each Bartonella species from Chile clustered together and with other Bartonella spp. described in cats worldwide. Bartonella henselae and B. clarridgeiae showed a low number of variable sites, haplotypes and nucleotide diversity. Bartonella clarridgeiae and B. koehlerae are reported for the first time in cats from Chile and South America, respectively.

  20. Holocene tephrostratigraphy of southern Chiloé Continental (Andean southern volcanic zone; ~43°S), Chile

    NASA Astrophysics Data System (ADS)

    Lachowycz, S.; Smith, V. C.; Pyle, D. M.; Mather, T. A.

    2012-12-01

    The eruptive history of the volcanoes in the southern part of the Andean Southern Volcanic Zone (42.5-45°S) is very poorly constrained: only several late Quaternary eruptions have been identified, mostly from study of sparse roadcuts [1]. In this study, we further constrain the Holocene explosive eruption history around 43°S by identifying and analysing tephra layers preserved in a ~3.25m long peat core from Cuesta Moraga [2], ~35km east of Yanteles volcano. Cryptotephra was extracted following the method of [3], in addition to macrotephra; owing to the vicinity of the sampling site to the tephra sources, cryptotephra was found throughout the core stratigraphy, but was sufficiently variable in concentration that discrete layers were identifiable and attributed to specific eruptions. Chemical analysis of the glass by electron microprobe shows that the tephra layers originate from a number of volcanoes in the region. This new tephrostratigraphy improves our knowledge of the important history of explosive volcanism in this area, potentially tying the tephrostratigraphies of surrounding areas (e.g., [4]) and allowing improved evaluation of regional volcanic risk. [1] Naranjo, J.A.., and C. R. Stern, 2004. Holocene tephrochronology of the southernmost part (42°30'-45°S) of the Andean Southern Volcanic Zone. Revista geológica de Chile, 31, pp. 225-240. [2] Heusser, C.J., et al., 1992. Paleoecology of late Quaterary deposits in Chiloé Continental, Chile. Revista Chilena de Historia Natural, 65, pp. 235-245. [3] Blockley, S.P.E., et al., 2005. A new and less destructive laboratory procedure for the physical separation of distal glass tephra shards from sediments. Quaternary Science Reviews, 24, pp. 1952-1960. [4] Watt, S.F.L., et al., 2011. Holocene tephrochronology of the Hualaihue region (Andean southern volcanic zone, ~42°S), southern Chile. Quaternary International, 246, pp. 324-343.

  1. The spider genus Cyrioctea Simon on Chañaral Island (Pingüino de Humboldt National Reserve, Atacama, Chile): description of a new species, and the male of Cyrioctea cruz Platnick (Araneae, Zodariidae).

    PubMed

    Grismado, Cristian J; Pizarro-Araya, Jaime

    2016-05-02

    A faunistic survey on Chañaral Island, Atacama, near the northern Pacific coast of Chile, allowed the discovery and description of a new species of the spider genus Cyrioctea: C. islachanaral sp. nov., based on females collected by pitfall traps. Strikingly, this new species shares morphological characters with some Southern African representatives of this genus rather than with the species of continental South America. The male of the species C. cruz Platnick, previously known from continental Chile (northern Coquimbo), is described for the first time based on specimens collected in the same locality.

  2. Chile.

    PubMed

    1992-05-01

    The background notes on Chile provide a statistical summary of the population, geography, government, and the economy, and more descriptive text on the history, population, government, economy, defense, and foreign relations. In brief, Chile has 13.3 million Spanish Indian (Mestizos), European, and Indian inhabitants and an annual growth rate of 1.6%. 96% are literate. Infant mortality is 18/1000. 34% of the population are involved in industry and commerce, 30% in services, 19% in agriculture and forestry and fishing, 7% in construction, and 2% in mining. The major city is Santiago. The government, which gained independence in 1810, is a republic with executive, legislative, and judicial branches. There are 12 regions. There are 6 major political parties. Suffrage is universal at 18 years. Gross domestic product (GDP) is $29.2 billion. The annual growth rate is 5% and inflation is 19%. Copper, timber, fish, iron ore, nitrates, precious metals, and molybdenum are its natural resources. Agricultural products are 9% of GDP and include wheat, potatoes, corn, sugar beets, onions, beans, fruits, and livestock. Industry is 21% of GDP and includes mineral refining, metal manufacturing, food and fish processing, paper and wood products, and finished textiles. $8.3 billion is the value of exports and $7 billion of imports. Export markets are in Japan, the US, Germany, Brazil, and the United Kingdom. Chile received $3.5 billion in economic aid between 1949-85, but little in recent years. 83% live in urban centers, principally around Santiago. Congressional representation is made on the basis of elections by a unique binomial majority system. Principal government officials are identified. Chile has a diversified free market economy and is almost self-sufficient in food production. The US is a primary trading partner. 49% of Chile's exports are minerals. Chile maintains diplomatic relations with 70 countries, however, relations are strained with Argentina and Bolivia. Relations

  3. Chile.

    PubMed

    1986-04-01

    In 1985, Chile's population stood at 12 million, with an annual growth rate of 1.7%. 1984's infant mortality rate was 20/1000 live births and life expectancy was 67 years. The literacy rate was 94%. Of the work force of 3,841,000 in 1985, 15.9% were engaged in agriculture, forestry, and fishing; 31.3% were employed in industry and commerce; 38.6% were in the service sector; 8.7% worked in mining; and 4.4% were employed in construction. Chile's military junta is scheduled to be replaced by an elected legislature in 1990. The GDP was US $19.2 billion in 1984, with an annual real growth rate of 6.3%, and per capita GDP stood at US$1590. Inflation averages 23%. Industry comprises 21% of the GDP. Longterm prospects for the Chilean economy are influenced by a high debt service ratio, very low domestic savings and investment, the prospect of little or no increase in copper prices, and continuing problems in the domestic financial sector. In 1985-88, under the International Monetary Fund macroeconomic program, Chile will strive for moderate economic growth while managing its external debt servicing burden.

  4. Deep Divergences within Liolaemus nigroviridis (Squamata, Liolaemidae) Lineages Associated with Sky Islands in Central Chile.

    PubMed

    Cianferoni, Franco; Yáñez, Romina P; Eduardo, R Eduardo; Garin, Carlos F; Torres-Pérez, Fernando

    2013-01-01

    Evolution of montane species may be strongly influenced by climate oscillations, particularly species distributed in isolated high-elevation areas (sky islands). Chilean topography is exemplified by montane environments including the Andes and Coastal Mountains. To test hypotheses related to genetic divergence associated with sky islands, we explored population genetics and phylogenetic signatures in the montane lizard Liolaemus nigroviridis Müller and Hellmich 1932. We sequenced the mitochondrial cytochrome b for samples collected from six montane areas in central Chile. We found high genetic divergence among populations, congruent with well-supported clades from phylogeny reconstructions. The most recent common ancestor of all samples of L. nigroviridis was dated around the limit of Pliocene-Pleistocene (2.7 Mya), congruent with early vicariance of Andean and coastal populations. Deep lineage divergences suggest that allopatric populations accumulated high nucleotide differences and maintained long periods without gene exchange. We discuss potential taxonomic revisions considering relative genetic divergence.

  5. Epidemiological description of the sea lice (Caligus rogercresseyi) situation in southern Chile in August 2007.

    PubMed

    Hamilton-West, Christopher; Arriagada, Gabriel; Yatabe, Tadaishi; Valdés, Pablo; Hervé-Claude, Luis Pablo; Urcelay, Santiago

    2012-05-01

    Salmon sea lice represent one of the most important threats to salmon farming throughout the world. Results of private monitoring efforts have shown an increase in the number of positive cages and cage-level abundance of sea lice in southern Chile since 2004. As a consequence, the Chilean Fisheries Service implemented an Official Surveillance Program in the main salmon production area of southern Chile to assess the situation of sea lice in fish farms. Results showed that the prevalence of sea lice in the fish farms was 53.4%, ranging from 3.5% in Puerto Aysén to 100% in the Seno de Reloncaví zone. The average sea lice abundance was 11.8 per fish (Geometrical mean (GM)=8.61, 95% CI (2.1-6.9)). The highest levels were found in Seno de Reloncaví (GM=24.99, 95% CI (15.9-39.2)), Hornopirén (GM=14.7, 95% CI (10.4-20.8)) and Chiloé norte (GM=9.75, 95% CI (1-1.9)), and the lowest loads were observed in Puerto Aysén (GM=1.35, 95%CI (1-1.9)) and Puerto Cisnes (GM=1.67, 95%CI (1.1-2.6)). Salmo salar and Oncorhynchus mykiss had the highest abundance levels (GM=6.93, 95% CI (5.7-8.5), and (GM=5.55, 95% CI (3.6-8.5), respectively). O. kisutch showed lower levels (GM=1.34, 95% CI (1-1.7)), apparently being more resistant to infestation. Sea lice in farmed salmon are widely distributed in different zones of southern Chile, and are becoming a serious threat to this industry. Prevalence and abundance levels were found to be generally high, decreasing in southern zones.

  6. Large slope instabilities in Northern Chile and Southern Peru

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni B.; Hermanns, Reginald L.; Valbuzzi, Elena; Frattini, Paolo; Valagussa, Andrea

    2014-05-01

    Deep canyon incision into Tertiary paleosurfaces and large slope instabilities along the canyon flanks characterize the landscape of western slope of the Andes of northern Chile and South Peru. This area belongs to the Coastal Escarpment and Precordillera and is formed by coarse-grained clastic and volcanoclastic formations. The area is characterized by intense seismicity and long-term hyperaridity (Atacama Desert). Landslides along the canyon flanks affect volumes generally up to 1 km3 and locally evolved in large rock avalanches. We prepared a landslide inventory covering an area of about 30,000 km2, extending from Iquique (Chile) to the South and Tacna (Peru) to the North. A total of 606 landslides have been mapped in the area by use of satellite images and direct field surveys, prevalently including large phenomena. The landslides range from 1 10-3 km2 to 464 km2 (Lluta landslide). The total landslide area, inclusive of the landslide scarp and of the deposit, amounts to about 2,130 km2 (about 7% of the area). The mega landslides can be classified as large block slides that can evolve in large rock avalanches (e.g. Minimini landslide). Their initiation seems to be strongly associated to the presence of secondary faults and large fractures transversal to the slope. These landslides show evidence suggesting a re-incision by the main canyon network. This seems particularly true for the Lluta collapse where the main 'landslide' mass is masked or deleted by the successive erosion. Other landslides have been mapped along the Coastal Escarpment and some of the major tectonic escarpments with an E-W trend. We examined area-frequency distributions of landslides by developing logarithmically binned, non-cumulative size frequency distributions that report frequency density as a function of landslide planar area A. The size frequency distribution presents a strong undersampling for smaller landslides, due to the extremely old age of the inventory. For landslides larger than

  7. Discovery of a blue whale feeding and nursing ground in southern Chile.

    PubMed

    Hucke-Gaete, Rodrigo; Osman, Layla P; Moreno, Carlos A; Findlay, Ken P; Ljungblad, Don K

    2004-05-07

    After the extensive exploitation that reduced the Southern Hemisphere blue whale (Balaenoptera musculus) populations to less than 3% of its original numbers, studies on its recovery have been compounded by the inaccessibility of most populations and the extensive migrations between low and high latitudes, thus ensuring that knowledge about blue whale ecology and status remains limited. We report the recent discovery of, arguably, the most important blue whale feeding and nursing ground known to date in the Southern Hemisphere, which is located near the fjords off southern Chile. Through aerial and marine surveys (n = 7) 47 groups, comprising 153 blue whales including at least 11 mother-calf pairs, were sighted during the austral summer and early autumn of 2003. The implications of this discovery on the biological understanding and conservation of this endangered species are discussed.

  8. Discovery of a blue whale feeding and nursing ground in southern Chile.

    PubMed Central

    Hucke-Gaete, Rodrigo; Osman, Layla P; Moreno, Carlos A; Findlay, Ken P; Ljungblad, Don K

    2004-01-01

    After the extensive exploitation that reduced the Southern Hemisphere blue whale (Balaenoptera musculus) populations to less than 3% of its original numbers, studies on its recovery have been compounded by the inaccessibility of most populations and the extensive migrations between low and high latitudes, thus ensuring that knowledge about blue whale ecology and status remains limited. We report the recent discovery of, arguably, the most important blue whale feeding and nursing ground known to date in the Southern Hemisphere, which is located near the fjords off southern Chile. Through aerial and marine surveys (n = 7) 47 groups, comprising 153 blue whales including at least 11 mother-calf pairs, were sighted during the austral summer and early autumn of 2003. The implications of this discovery on the biological understanding and conservation of this endangered species are discussed. PMID:15252974

  9. Does bird species diversity vary among forest types? A local-scale test in Southern Chile

    NASA Astrophysics Data System (ADS)

    Fontúrbel, Francisco E.; Jiménez, Jaime E.

    2014-10-01

    Birds are the most diverse vertebrate group in Chile, characterized by low species turnover at the country-size scale (high alpha but low beta diversities), resembling an island biota. We tested whether this low differentiation is valid at a local scale, among six forest habitat types. We detected 25 bird species; avifauna composition was significantly different among habitat types, with five species accounting for 60 % of the dissimilarity. We found a higher level of bird assemblage differentiation across habitats at the local scale than has been found at the country-size scale. Such differentiation might be attributed to structural differences among habitats.

  10. Interactions of Marine Hydrokinetic Devices in Complex Bathymetries: Numerical Simulations in the Chacao Channel in Southern Chile.

    NASA Astrophysics Data System (ADS)

    Soto, K. A.; Escauriaza, C. R.; Richter, D. H.

    2015-12-01

    Many coastal areas in the South Pacific Ocean can provide significant marine energy resources in the near future. The installation of marine hydrokinetic (MHK) devices in these regions will require new approaches to understand physical and environmental processes that are relevant for the installation of turbine arrays, which are also specific of each site. The coastal morphology of the Chacao channel in southern Chile, which separates the Chiloé island from the main continent (41º47'S, 73º31'W) stands out as an important energy resource that can potentially contribute a significant power capacity. This coastal area not only sustains delicate ecosystems with limited anthropic intervention, but it is characterized by a complex bathymetry that can have important effects on the performance of MHK devices and their local impacts. To understand the interactions of the local bathymetry and ambient turbulence with turbine arrays, we carry out a series of numerical simulations with a coherent-structure resolving turbulence model using the actuator disk parameterization. The main objective of this study is to further our understanding on the physical processes associated with the installation of the turbine arrays. We perform simulations with different geometries and inlet boundary conditions, from simple cases in a rectangular channel, to more complex cases that include the high-resolution bathymetry of an extensive area of the Chacao channel. The results show how the interactions between the MHK devices, the local flow, and the bed can affect the energy flux and potential generation in specific sites. The results also provide new insights of local impacts of MHK devices and they can also help to optimize turbine arrays in natural environments. This work has been supported by Fondecyt project 1130940, and the Marine Energy Research & Innovation Center (MERIC) financed by Corfo and based in Santiago, Chile.

  11. Radiological conditions at the Southern Islands of Rongelap Atoll

    SciTech Connect

    Robison, W.L.; Conrado, C.L.

    1996-03-01

    The data presented in the following tables is the total available for each southern island; they include both the data from the 1978 Northern Marshall Island Radiological Survey (NMIRS) and trips to Rongelap Atoll from 1986 through 1991. There are additional samples that were taken at Rongelap Island in 1990 and 1991, and the data are unavailable for this report. In one table we present the number of vegetation samples collected in the 1978 NMIRS and from 1986 through 1991. Again, the majority of the {sup 137}Cs is from the 1986-1991 trips. We have not made additional analyses of {sup 239+240}Pu, {sup 241}Am and {sup 90}Sr because the concentrations are very low and these radionuclides contribute less than 5% of an already very small dose. In another table we show the number of soil samples collected at each island in 1978 and the number collected since 1986. Most of the data are from 1986 through 1991. The major exception is {sup 90}Sr where all of the data are from the 1978 NMIRS. We have done some additional Pu analyses of soils from Rongelap Eniaetok, and Borukka Island but none of the other southern islands. A significant amount of new data for {sup 137}Cs and {sup 241}Am have been generated from the samples collected from 1986 through 1991. The data are presented in the form of summary tables, graphics, detailed appendices and aerial photographs of the islands with the sample locations marked. The identified sample locations from the 1978 NMIRS will be added later.

  12. A network analysis of plant-pollinator interactions in temperate rain forests of Chiloé Island, Chile.

    PubMed

    Ramos-Jiliberto, Rodrigo; Albornoz, Abraham A; Valdovinos, Fernanda S; Smith-Ramírez, Cecilia; Arim, Matías; Armesto, Juan J; Marquet, Pablo A

    2009-07-01

    This study characterizes the structure of a plant-pollinator network in a temperate rain forest of Chiloé Island, southern Chile, where woody species are strongly dependent on biotic pollinators, and analyzes its robustness to the loss of participating species. Degree distribution, nestedness, and expected species persistence were evaluated. In addition, we assessed the roles of predefined subsets of plants (classified by life forms) and pollinators (grouped by taxonomic orders) in the network's structure and dynamics. For this, we simulated the complete removal of each plant and pollinator subset and analyzed the resultant connectivity patterns, as well as the expected long-term species losses by running a stochastic model. Finally, we evaluated the sensitivity of the network structure to the loss of single species in order to identify potential targets for conservation. Our results show that the plant-pollinator network of this Chilean temperate rain forest exhibits a nested structure of interactions, with a degree distribution best described by a power law model. Model simulations revealed the importance of trees and hymenopterans as pivotal groups that maintain the core structure of the pollination network and guarantee overall species persistence. The hymenopterans Bombus dahlbomii and Diphaglossa gayi, the shrubs Tepualia stipularis and Ugni molinae, the vines Mitraria coccinea and Asteranthera ovata, and the entire set of tree species exerted a disproportionately large influence on the preservation of network structure and should be considered as focal species for conservation programs given current threats from selective logging and habitat loss.

  13. Description of the Terrestrial Larva of Parosca latipalpis (Macquart) (Diptera: Tabanidae) from Southern Chile.

    PubMed

    González, C R; Llanos, L; Saldarriaga-Córdoba, M

    2016-10-01

    The terrestrial larva of the austral horsefly, Parosca latipalpis (Macquart), identified by molecular techniques, is described. The larva of P. latipalpis resembles Scaptia auriflua (Donovan), Copidapha vicina (Taylor), Myioscaptia muscula (English), and Osca lata (Guérin-Meneville) in many morphological characters, as well as in their terrestrial habitats. Some characters that are shared between these species are unique among Tabanidae and provide evidence of their monophyletic origin, suggesting a typical Gondwanaland group. Larvae of P. latipalpis were found 2-3 cm below of the soil surface and associated with larvae of Coleoptera, Lepidoptera, and Diptera in southern Chile.

  14. Plateurytion roigi sp. nov., a new geophilid centipede (Myriapoda: Chilopoda: Geophilomorpha) from Southern Chile.

    PubMed

    Pereira, Luis Alberto

    2016-09-09

    Plateurytion roigi sp. nov. (Chilopoda: Geophilomorpha: Geophilidae) is fully described and illustrated from the holotype female from southern Chile (Region X (de Los Lagos region): Palena province). The new species seems particularly similar to P. gracilis (Gervais, 1849) (from Chile and Argentina), to which it is accordingly compared in detail for a confident identification. This is the sixth report of a species of the genus Plateurytion Attems, 1909, from Chile. The others are P. gracilis (Gervais, 1849); P. metopias (Attems, 1903); P. michaelseni (Attems, 1903); P. mundus (Chamberlin, 1955); and P. zapallar (Chamberlin, 1955). New geographic records are given for Plateurytion mauryi Pereira, 2008, which is reported for the first time from San Juan province, up to now only known from the type locality (in Mendoza province), central-western Argentina. Plateurytion yungarum (Pereira, 2005), is reported from the montane cloud forest altitudinal level of the Yungas forest of northwestern Argentina, until now it has only been recorded from the (lowest) montane forest altitudinal level of the Yungas.

  15. Metazoan parasites of Brama australis from southern Chile: a tool for stock discrimination?

    PubMed

    Oliva, M E; Espinola, J F; Ñacari, L A

    2016-03-01

    The metazoan parasites of 403 specimens of the southern ray's bream Brama australis from three localities in southern Chile (Lebu 36° 70' S; 73° 40' W, Calbuco 41° 50' S; 73° 08' W and Punta Arenas 53° 10' S; 70° 50' W) were recorded. More than 23 400 parasite specimens belonging to 12 taxa were registered. Metazoan parasites were dominated by the copepod Hatschekia conifera, constituting 97% of the total number of parasites; the larval cestode Hepatoxylon trichiuri was the second most important parasite (2·1% of the total number of parasites). The remaining 10 species constituted <1% of the metazoan parasites. Parasitological evidence, based on univariate and multivariate analysis, does not support the existence of discrete stocks in the studied zone. © 2016 The Fisheries Society of the British Isles.

  16. Assessment of the Chile 2010 and Japan 2011 Tsunami Events in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Renteria, Willington; Lynett, Patrick

    2015-04-01

    The object of this study is to present an analysis of measurements and observations from the Chile 2010 and Japan 2011 tsunamis, in order to understand the particular response of the Galápagos Islands to the occurrence of these extreme events. There was very limited data measured in the Galápagos during the tsunami events, other than a high-frequency and continuous record of each event logged at the two tidal gauge stations. With this data, a wavelet analysis is performed with the aim of discriminating different patterns in wave periods along the record of observation and to recognize the frequency response of the islands to an incoming tsunami. During both events, a clear and persistent signal is found in the period range of ten to twelve minutes for Baltra tide gauge, and in the range of seventeen to twenty minutes for Santa Cruz tide gauge. Both of these persistent signals are speculated to be a shelf resonant mode particular to the Galápagos Islands and the Galápagos Platform.

  17. Molecular epidemiology of hospital-onset methicillin-resistant Staphylococcus aureus infections in Southern Chile.

    PubMed

    Medina, G; Egea, A L; Otth, C; Otth, L; Fernández, H; Bocco, J L; Wilson, M; Sola, C

    2013-12-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of public health importance. In Chile, the Cordobes/Chilean clone was the predominant healthcare-associated MRSA (HA-MRSA) clone in 1998. Since then, the molecular epidemiological surveillance of MRSA has not been performed in Southern Chile. We aimed to investigate the molecular epidemiology of HA-MRSA infections in Southern Chile to identify the MRSA clones involved, and their evolutionary relationships with epidemic international MRSA lineages. A total of 303 single inpatient isolates of S. aureus were collected in the Valdivia County Hospital (2007-2008), revealing 33% (100 MRSA/303) prevalence for HA-MRSA infections. The SCCmec types I and IV were identified in 97% and 3% of HA-MRSA, respectively. All isolates lacked the pvl genes. A random sample (n = 29) of all MRSA was studied by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), SCCmec subtyping, agr and spa typing, and virulence genes profiling. PFGE analysis revealed the predominance (89%, 26/29) of pulsotype A and three additional pulsotypes, designated H1, I33, and G1. Pulsotype A (ST5-SCCmecI-spa-t149) is clonally related to the Cordobes/Chilean clone. Pulsotype H1 (ST5-SCCmecIVNT-spa-t002) is genetically related to the Pediatric clone (ST5-SCCmecIV). Pulsotype I33 (ST5-SCCmecIVc-spa-t002) is clonally related by PFGE to the community-associated MRSA (CA-MRSA) clone spread in Argentina, I-ST5-IVa-PVL(+). The G1 pulsotype (ST8-SCCmecIVc-spa-t024) is clonally related to the epidemic USA300 CA-MRSA. Here, we demonstrate the stability of the Cordobes/Chilean clone over time as the major HA-MRSA clone in Southern Chile. The identification of two CA-MRSA clones might suggest that these clones have entered into the healthcare setting from the community. These results emphasize the importance of the local surveillance of MRSA infections in the community and hospital settings.

  18. Comparative analysis of the impact of geological activity on the structural design of telescope facilities in the Canary Islands, Hawaii and Chile

    NASA Astrophysics Data System (ADS)

    Eff-Darwich, A.; García-Lorenzo, B.; Rodriguez-Losada, J. A.; de La Nuez, J.; Hernández-Gutiérrez, L. E.; Romero-Ruiz, M. C.

    2010-09-01

    An analysis of the impact of seismic and volcanic activity has been carried out at selected astronomical sites, namely the observatories of El Teide (Tenerife, Canary Islands), Roque de los Muchachos (La Palma, Canary Islands), Mauna Kea (Hawaii) and Paranal (Chile), and the candidate site of Cerro Ventarrones (Chile). Hazard associated with volcanic activity is low or negligible at all sites, whereas seismic hazard is very high in Chile and Hawaii. The lowest geological hazard in both seismic and volcanic activity is found at Roque de los Muchachos observatory, on the island of La Palma.

  19. Resurrection Peninsula and Knight Island ophiolites and recent faulting on Montague Island, southern Alaska

    USGS Publications Warehouse

    Nelson, Steven W.; Miller, Marti L.; Dumoulin, Julie A.

    1987-01-01

    The Resurrection Peninsula forms the east side of Resurrection Bay (Fig. 1). The city of Seward is located at the head of the bay and can be reached from Anchorage by highway (127 mi;204 km). Relief ranges from 1,434 ft (437 m) at the southern end of the peninsula to more than 4,800 ft (1,463 m) 17 mi (28 km) to the north. All rock units composing the informally named Resurrection Peninsula ophiolite are visible and (or) accessible by boat.The eastern half of the peninsula is located within the Chugach National Forest; the western half is mainly state land, but there is some private land with recreational cabins. The Seward A6 and A7 and Blying Sound D6 and D7 maps at 1:63,360 scale (mile-to-the-inch) cover the entire Resurrection Peninsula.Knight Island is located 53 mi (85 km) east of Seward (Fig. 1). Numerous fiords indent the 31-mi-long (50 km) by 7.4-mi-wide (12 km) island and offer excellent bedrock exposures. The island is rugged and has a maximum elevation of 3,000 ft (914 m). It has numerous mineral prospects (Tysdal, 1978; Nelson and others, 1984; Jansons and others, 1984; Koski and others, 1985), and several abandoned canneries are located on the island. Knight Island lies entirely within the Chugach National Forest—state and private inholdings constitute less than five percent of its total land area. The Seward A2, A3, B2, B3, and C2, 1:63,360-scale U.S. Geological Survey topographic maps cover the entire island.Montague Island, 50 mi (80 km) long and up to 11 mi (18 km) wide, lies 10.6 mi (17 km) southeast of Knight Island. It belongs to an island group that forms the southern margin of Prince William Sound (Fig. 1). Montague Island is less rugged and less heavily vegetated than either the Resurrection Peninsula or Knight Island. Rock exposures are excellent along the beaches, and ground disruption due to recent fault movements is clearly visible. The Seward Al and A2 and Blying Sound Dl, D2, and D3 maps cover the areas of interest on Montague Island

  20. Modern rates of glacial sediment accumulation along a 15° S-N transect in fjords from the Antarctic Peninsula to southern Chile

    NASA Astrophysics Data System (ADS)

    Boldt, Katherine V.; Nittrouer, Charles A.; Hallet, Bernard; Koppes, Michele N.; Forrest, Brittany K.; Wellner, Julia S.; Anderson, John B.

    2013-12-01

    of glacial erosion in temperate climates rank among the highest worldwide, and the sedimentary products of such erosion record climatic and tectonic signals in many glaciated settings, as well as temporal changes in glacier behavior. Glacial sediment yields are expected to decrease with increasing latitude because decreased temperature and meltwater production reduce glacial sliding, erosion, and sediment transfer; however, this expectation lacks a solid supportive database. Herein we present modern 210Pb-derived sediment accumulation rates on decadal to century time scales for 12 fjords spanning 15° of latitude from the Antarctic Peninsula to southern Chile and interpret the results in light of glacimarine sediment accumulation worldwide. 210Pb records from the Antarctic Peninsula show surprisingly steady sediment accumulation throughout the past century at rates of 1-7 mm yr-1, despite rapid warming and glacial retreat. Cores from the South Shetland Islands reveal accelerated sediment accumulation over the past few decades, likely due to changes in the thermal state of the glaciers in this region, which straddles the boundary between subpolar and temperate conditions. In Patagonia and Tierra del Fuego, sediment accumulates faster (11-24 mm yr-1), and previously collected seismic profiles show that rates reach meters per year close to the glacier termini. This increase in sediment accumulation rates with decreasing latitude reflects the gradient from subpolar to temperate climates and is consistent with glacial erosion being much faster in the temperate climate of southern Chile than in the polar climate of the Antarctic Peninsula.

  1. Southern-ocean and glaciogenic nutrients control diatom export production on the Chile margin

    NASA Astrophysics Data System (ADS)

    Chase, Zanna; McManus, James; Mix, Alan C.; Muratli, Jesse

    2014-09-01

    Biogenic particle flux was reconstructed using 230-Thorium normalization at two sites on the southern Chile margin. ODP Site 1233 at 41°S, 838 m depth, is at the southern limit of the Peru-Chile upwelling system, where the northern extent of the Antarctic Circumpolar Current impinges on the South American continental margin. ODP Site 1234, at 36°S, 1014 m depth, is located within the core of the coastal upwelling system near the mouths of the Bio Bio and Itata Rivers. At 41°S, opal, lithogenic and carbonate fluxes are greatest during the Last Glacial interval (26-20 ka), carbonate has a secondary peak during the mid Holocene (˜8 ka) and organic carbon fluxes increase slightly from 17 ka to the present. At 36°S, large lithogenic fluxes are observed both during the Last Glacial interval and the Holocene, and a maximum in organic carbon flux is observed during the late Holocene (˜5 ka) without an accompanying peak in opal flux. These reconstructed fluxes at 36°S and 41°S fit within a larger latitudinal pattern of a poleward increase in the magnitude of opal flux during the glacial period. The pattern of normalized opal flux, opal mass accumulation rate and opal:carbonate ratios is consistent with either i) enhanced supply of Si from the Southern Ocean, as proposed by the Silicic Acid Leakage Hypothesis or ii) enhanced Si and Fe delivery from land, driven by glacial erosion. The pattern of reconstructed export production supports our view that the appearance of more reducing conditions in the sediments upon deglaciation was most likely driven by decreased ventilation, rather than increased local productivity.

  2. Educating "Barbaros": Educational Policies on the Latin American Frontiers between Colonies and Independent Republics (Araucania, Southern Chile/Sonora, Mexico)

    ERIC Educational Resources Information Center

    Holck, Lasse; Saiz, Monika Contreras

    2010-01-01

    This article compares the methods and means employed by the state to enforce the education of (semi-)autonomous indigenous groups in southern Chile and northwestern Mexico (Sonora), border regions in the Latin American periphery, covering the transition from colonial times to the consolidation of independent republics until the middle of the…

  3. Metabolizable energy intake effects on tympanic temperature and ADG of steers finished in southern Chile during summer

    USDA-ARS?s Scientific Manuscript database

    A total of 24 red Angus steers (BW = 431.16 ± 10.44) were used to assess the effect of metabolizable energy intake (MEI) on ADG and tympanic temperature (TT) during the summer time in southern Chile. Steers were sorted by BW (lighter or heavier) and allocated in 4 pens (6 head/pen) equipped with a C...

  4. Effects of metabolizable energy intake on tympanic temperature and average daily gain of steers finished in southern Chile during wintertime

    USDA-ARS?s Scientific Manuscript database

    A total of 24 Angus x Hereford steers (BW = 479.8 ± 4.48) were used to assess the effect of Metabolizable Energy Intake (MEI) on Average Daily Gain (ADG) and Tympanic Temperature (TT) during the wintertime in southern Chile. The study was conducted at the experimental field of the Catholic Universit...

  5. Educating "Barbaros": Educational Policies on the Latin American Frontiers between Colonies and Independent Republics (Araucania, Southern Chile/Sonora, Mexico)

    ERIC Educational Resources Information Center

    Holck, Lasse; Saiz, Monika Contreras

    2010-01-01

    This article compares the methods and means employed by the state to enforce the education of (semi-)autonomous indigenous groups in southern Chile and northwestern Mexico (Sonora), border regions in the Latin American periphery, covering the transition from colonial times to the consolidation of independent republics until the middle of the…

  6. Late Holocene Lacustrine Records of Climate and Vegetation Change From Southern Patagonia, Chile

    NASA Astrophysics Data System (ADS)

    Moy, C. M.; Francois, J.; Moreno, P.; Villa Martinez, R.; Dunbar, R. B.

    2004-12-01

    The westerly wind field is one of the most prominent atmospheric circulation features in the Southern Hemisphere, having a major impact on the climate of Chile and hydrographic conditions in the Southern Ocean. The latitudinal position and strength of the westerlies directly influences the amount and isotopic composition of precipitation that falls in southern Chile. Although instrumental records provide information on how the westerlies have varied over the recent past there is still an incomplete understanding of how the strength and latitudinal position of the southern westerlies have changed during the Holocene and how the wind field has varied at millennial to sub-decadal timescales. In this study we relate changes in the westerly winds to changes in water balance as recorded in closed-basin lakes. Sediment cores were obtained from Laguna Guanacos in Parque Nacional Torres del Paine (51° S, 72° W) during the austral summer of 2004 and sampled at 1-2cm intervals for pollen, charcoal, and stable isotope analysis. Laguna Guanacos is a small closed-basin lake situated in the core of westerly wind belt and is therefore sensitive to fluctuations in the strength and position of the westerlies. The sediment cores obtained from the lake reveal high concentrations of organic mater ( ˜20%) and biogenic carbonate, which is rare in Chilean Patagonia. AMS radiocarbon dates on the organic and carbonate fractions indicate that the record spans the last ˜14,000 calendar years and modern dates from core tops suggest little influence by old or dead carbon sources. Pollen analysis on the late Holocene portion of the record reveals a significant expansion of the Nothofagus forest since ˜3500 cal yr BP, suggesting an overall increase in precipitation during this interval. Millennial- and centennial-scale fluctuations in bulk carbonate content and forest and steppe pollen are superimposed upon this pattern, providing a view of a highly dynamic westerly wind regime and forest

  7. Polyphenols and antioxidant activity of calafate ( Berberis microphylla ) fruits and other native berries from Southern Chile.

    PubMed

    Ruiz, Antonieta; Hermosín-Gutiérrez, Isidro; Mardones, Claudia; Vergara, Carola; Herlitz, Erika; Vega, Mario; Dorau, Carolin; Winterhalter, Peter; von Baer, Dietrich

    2010-05-26

    Calafate ( Berberis microphylla ) is a native berry grown in the Patagonian area of Chile and Argentina. In the present study the phenolic composition and antioxidant activity of its fruits were studied and also compared with data obtained for other berry fruits from southern Chile including maqui ( Aristotelia chilensis ) and murtilla ( Ugni molinae ). Polyphenolic compounds in calafate fruit were essentially present in glycosylated form, 3-glucoside conjugates being the most abundant anthocyanins. The anthocyanin content in calafate berries (17.81 +/- 0.98 micromol g(-1)) and flavonol level (0.16 +/- 0.01 micromol g(-1)) are comparable with those found in maqui (17.88 +/- 1.15 and 0.12 +/- 0.01 micromol g(-1), respectively); however, maqui shows lower flavan-3-ol concentration than calafate (0.11 +/- 0.01 and 0.24 +/- 0.03 micromol g(-1), respectively). Maqui and calafate show high antioxidant activity, which correlates highly with total polyphenol content and with anthocyanin concentration.

  8. The effects of NO3(-) supply on Mazzaella laminarioides (Rhodophyta, Gigartinales) from southern Chile.

    PubMed

    Navarro, Nelso P; Figueroa, Félix L; Korbee, Nathalie; Mansilla, Andrés; Matsuhiro, Betty; Barahona, Tamara; Plastino, Estela M

    2014-01-01

    The effects of nitrate supply on growth, pigments, mycosporine-like amino acids (MAAs), C:N ratios and carrageenan yield were investigated in Mazzaella laminarioides cultivated under solar radiation. This species is economically important in southern Chile where an increase of nitrogen in coastal waters is expected as a consequence of salmon aquaculture activity. Apical segments were cultivated in enriched seawater with five different NO3(-) concentrations (0, 0.09, 0.18, 0.38 and 0.75 mm) during 18 days. Although phycoerythrin and phycocyanin content, as well as C:N ratios, were reduced in the control treatment (without NO3(-) supply), when compared to NO3(-) treatments, total MAA concentration, carrageenan yield and growth rates were similar in all tested conditions. Nevertheless, during the experiment, an important synthesis of mycosporine-glycine took place in a nitrate concentration-dependent manner, with accumulation being saturated around 0.18 mm of nitrate. These results indicate that exposure to high NO3(-) concentration of more than 100 times the values observed in the nature did not impair the photoprotection system, as determined by MAAs, nor did it have a deleterious effect on growth or carrageenan yield of M. laminarioides, a late successional species from Chile. © 2014 The American Society of Photobiology.

  9. Nutrients dynamics in the main river basins of the centre-southern region of Chile.

    PubMed

    Pizarro, Jaime; Vergara, Pablo M; Rodríguez, José A; Sanhueza, Pedro A; Castro, Sergio A

    2010-03-15

    Chilean basins have long been exposed to nutrient discharges from human activities and land use changes. A historical seasonal NO(3)(-)-N and PO(4)(3-)-P database of the last 23 years of the main nine rivers of central-southern region of Chile was analysed. Generalized additive models indicated that annual trends in NO(3)(-)-N and PO(4)(3-)-P are nonlinear. River basins such as Bío-Bío, Bueno, Imperial, Maule, Rapel and Valdivia showed a clear increase in NO(3)(-)-N, while PO(4)(3-)-P increased only in the Rapel and Maule basins. Although no seasonal difference in NO(3)(-)-N and PO(4)(3-)-P was found in the analysed basins, there was a negative relation between these nutrients and water flow. Sampling stations with high NO(3)(-)-N concentration were found mostly in sub-basins located in the "central valley" of central Chile, while several PO(4)(3-)-P "over-concentrated" sampling stations were located mostly upstream. If NO(3)(-)-N emissions into Chilean river basins continue at current rates it is probable that the concentration of this nutrient will tend to match that of the most "polluted" rivers around the world. (c) 2009 Elsevier B.V. All rights reserved.

  10. Interhemispheric climate links revealed by late-glacial cooling episode in southern Chile.

    PubMed

    Moreno, P I; Jacobson, G L; Lowell, T V; Denton, G H

    2001-02-15

    Understanding the relative timings of climate events in the Northern and Southern hemispheres is a prerequisite for determining the causes of abrupt climate changes. But climate records from the Patagonian Andes and New Zealand for the period of transition from glacial to interglacial conditions--about 14.6-10 kyr before present, as determined by radiocarbon dating--show varying degrees of correlation with similar records from the Northern Hemisphere. It is necessary to resolve these apparent discrepancies in order to be able to assess the relative roles of Northern Hemisphere ice sheets and oceanic, atmospheric and astronomical influences in initiating climate change in the late-glacial period. Here we report pollen records from three sites in the Lake District of southern Chile (41 degrees S) from which we infer conditions similar to modern climate between about 13 and 12.2 14C kyr before present (BP), followed by cooling events at about 12.2 and 11.4 14C kyr BP, and then by a warming at about 9.8 14C kyr BP. These events were nearly synchronous with important palaeoclimate changes recorded in the North Atlantic region, supporting the idea that interhemispheric linkage through the atmosphere was the primary control on climate during the last deglaciation. In other regions of the Southern Hemisphere, where climate events are not in phase with those in the Northern Hemisphere, local oceanic influences may have counteracted the effects that propagated through the atmosphere.

  11. Purification and characterization of saxitoxin from Mytilus chilensis of southern Chile.

    PubMed

    Rubio, D P; Roa, L G; Soto, D A; Velasquez, F J; Gregorcic, N A; Soto, J A; Martinez, M C; Kalergis, A M; Vasquez, A E

    2015-12-15

    In the current communication we describe an innovative method to purify saxitoxin (STX), a toxin presents in contaminated muscle of Mylitus chilensis extracted in the southern part of Chile, using a liquid chromatographic methodology based on ionic pairs. The STX was extracted using HCl and treated with ammonium sulfate following a treatment with trichloroacetic acid and hexane/diethyl ether (97/3). The samples were analyzed by a semi-preparative HPLC in order to collect pure fractions of STX and these fractions were eluted in solid-phase cationic interchange SCX extraction columns. The purified STX was stable and homogeneous and its identity was confirmed by LC-MS-MS, which demonstrated a high quality purification of STX, without presence of analogs such as neosaxitoxin (Neo) and decarbamoyl saxitoxin (dcSTX). The STX biological activity was analyzed in a bioassay in mice model and compared to the standard STX produced by the FDA and no significant differences were observed.

  12. Hydrochemical Modeling of Dissolved Organic Carbon in a Small, Undisturbed, Forested Watershed in Southern Chile

    NASA Astrophysics Data System (ADS)

    Valdivia, M. V.; Walter, M. T.; Salmon, C. D.; Hedin, L. O.; Walter, M. F.

    2004-12-01

    The objective of the present study is to model Dissolved Organic Carbon (DOC) concentrations in a stream draining a small, undisturbed, old-growth forested watershed in Southern Chile and test model results against measured data. DOC plays an important role in several processes in terrestrial and aquatic ecosystems. For example, through the formation of organic complexes, DOC can influence nutrient availability, affect the solubility, mobility, and toxicity of metals, and control the absorption of pesticides to soils. DOC also influences biological activity by absorbing UV-B radiation and can contribute significantly to freshwater acidity. Additionally, DOC is linked to the formation of trihalomethanes as by-products of the disinfection of drinking water with chlorine, which constitutes a potentially serious threat to human health. Despite plentiful research on biogeochemical processes controlling DOC production and consumption, there is little information from minimally impacted environments, which can provide valuable baseline information from which to evaluate the more impacted ecosystems. Our study focused on a virtually unpolluted old-growth forested watershed in Southern Chile. We developed a conceptual model that assumes DOC production in forest soils is a function of temperature and DOC transport from soil to stream water is a function of discharge and hydrological flow paths. The hydrological response of the catchment under study was simulated using a simple lumped model, based on two years of meteorological data previously collected. Three different equations were used to simulate DOC concentrations in soil water as a function of temperature, and ultimately to derive DOC concentrations in streamflow. Model results were tested against two years of measured DOC concentrations in streamflow, and all three models provided a reasonably good representation of the DOC response of the small studied watershed and a better agreement to the observed DOC than

  13. Epidemiology of Strongyloides stercoralis on Mekong islands in southern Laos.

    PubMed

    Vonghachack, Youthanavanh; Sayasone, Somphou; Bouakhasith, Dalouny; Taisayavong, Keoka; Akkavong, Kongsap; Odermatt, Peter

    2015-01-01

    Strongyloides stercoralis is a neglected helminth infection potentially that can lead to systemic infection in immunocompromised individuals. In Lao People's Democratic Republic (Lao PDR, Laos), information on S. stercoralis infection is scarce. We assessed S. stercoralis infection and associated risk factors and symptoms on the Mekong islands in Southern Laos. Baermann and Kato-Katz techniques were performed on two stool samples from each individual to detect S. stercoralis larvae and concomitant helminth infections. Among 729 individuals, 41.0% were infected with S. stercoralis. Men were at higher risk than women (OR 1.97, 95% CI 1.45-2.67). Urticaria and body itching was associated with S. stercoralis infection (OR 2.4, 95% CI 1.42-4.05). Infection with Opisthorchis viverrini (72.2%), Schistosoma mekongi (12.8%), and hookworm (56.1%) were very common. Few infections with Trichuris trichiura (3.3%), Ascaris lumbricoides (0.3%) and Taenia spp. (0.3%) were detected. The majority of helminth infections were of light intensity, with prevalences of 80.4%, 92.9%, 64.5%, 100% and 100%, for O. viverrini, hookworm, S. mekongi, T. trichiura and A. lumbricoides, respectively. Nevertheless, heavy infection intensities were observed for O. viverrini (1.0%), S. mekongi (14.0%) and hookworm (2.9%). S. stercoralis is highly endemic on the islands of Khong district, Champasack province, Southern Laos. The national helminth control programme should take action to control this helminth infection.

  14. Re-establishment of the IMS Hydroacoustic Station HA03, Robinson Crusoe Island, Chile

    NASA Astrophysics Data System (ADS)

    Haralabus, Georgios; Stanley, Jerry; Zampolli, Mario; Pautet, Lucie

    2015-04-01

    Water column hydrophone stations of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) International Monitoring System (IMS) comprise typically two triplets of moored hydrophones deployed on both sides of an island. Triplet distances vary approximately between 50 - 200 km from the island, with each triplet connected to the receiving shore equipment by fibre-optic submarine data cables. Once deployed, the systems relay underwater acoustic waveforms in the band 1 - 100 Hz in real time to Vienna via a shore based satellite link. The design life of hydroacoustic (HA) stations is at least 20 years, without need for any maintenance of the underwater system (UWS). The re-establishment of hydrophone station HA03 at Robinson Crusoe Island (670 km West of the Chilean mainland) is presented here. The station was destroyed in February 2010 by a Tsunami induced by an 8.8 magnitude earthquake. After a major engineering and logistical undertaking HA03 is now back in operation since April 2014. The main phases of the project are presented: (i) the installation of a shore facility for the reception of the hydrophone data from the UWS, which also relays the data back to the CTBTO International Data Center (IDC) in Vienna via a real-time satellite connection, (ii) the manufacturing and testing of the system to meet the stringent requirements of the Nuclear-Test-Ban Treaty, and (iii) the installation of the UWS with a state-of-the-art cable ship. Examples of data acquired by HA03 are also presented. These include hydroacoustic signals from the 1 April 2014 magnitude 8.2 earthquake in Northern Chile, bursting underwater bubbles from a submarine volcano near the Mariana Islands (15,000 Km away from the station), and vocalizations from the numerous marine mammals which transit in the vicinity of HA03. The use of CTBTO data for scientific purposes is possible via the virtual Data Exploitation Centre (vDEC), which is a platform that enables registered researchers to access

  15. Islands of Education: Schooling, Civil War and the Southern Sudanese (1983-2004)

    ERIC Educational Resources Information Center

    Sommers, Marc

    2005-01-01

    Victims of warfare, famine, slavery, and isolation, the Southern Sudanese are one of the most undereducated populations in the world. Since the inception of formal education in southern Sudan a century ago, schooling has largely consisted of island-like entities surrounded by oceans of educational emptiness. Islands of Education is the first book…

  16. Floating marine debris in fjords, gulfs and channels of southern Chile.

    PubMed

    Hinojosa, Iván A; Thiel, Martin

    2009-08-01

    Floating marine debris (FMD) is reported from all oceans. The bulk of FMD are plastics, which due to their longevity cause multiple negative impacts on wildlife and environment. Identifying the origins of FMD (land- or sea-based) is important to take the necessary steps to diminish their abundance. Using ship surveys we examined the abundance, composition and distribution of FMD during the years 2002-2005 in the fjords, gulfs and channels of southern Chile. Abundances of FMD were relatively high compared with other studies, ranging from 1 to 250 items km(-2). The majority (approximately 80%) of FMD was composed of styrofoam (expanded polystyrene), plastic bags and plastic fragments. Styrofoam, which is intensively used as flotation device by mussel farms, was very abundant in the northern region but rarely occurred in the southern region of the study area. Food sacks from salmon farms were also most common in the northern region, where approximately 85% of the total Chilean mussel and salmon harvest is produced. Plastic bags, which could be from land- or sea-based sources, were found throughout the entire study area. Our results indicate that sea-based activities (mussel farming and salmon aquaculture) are responsible for most FMD in the study area. In order to reduce FMDs in the environment, in addition to stronger legislation and identification of potential sources, we suggest environmental education programs and we encourage public participation (e.g. in beach surveys and clean-ups).

  17. Aerial arthropod communities of native and invaded forests, Robinson Crusoe Island, Chile.

    PubMed

    Hagen, Erin N; Bakker, Jonathan D; Gara, Robert I

    2010-08-01

    Invasive species significantly contribute to biological change and threaten biodiversity, with a growing body of evidence that plant invasions affect higher trophic levels. We explored the relative importance of plant invasion and forest structure on aerial arthropod abundance, diversity, and composition on Robinson Crusoe Island, Chile. We used flight intercept traps to sample aerial arthropods within distinct canopy strata of native and invaded forests over 3-mo periods in 2006 and 2007. Arthropod abundance and diversity were higher in native than invaded forest, and arthropod communities were distinct between forest types. In both forest types, arthropod abundance was highest in the lower canopy, and canopy strata exhibited some differences in arthropod community composition. Several morphospecies were distinctly associated with each forest type. The strong differences in aerial arthropod communities associated with the invasion of native forest by non-native plants may affect other trophic levels, such as insectivorous birds. Steps to stop invasive plant spread and to restore native forest composition and structure are needed to safeguard the integrity of native communities, from plants to higher-level consumers.

  18. Hydrodynamics of the 1868 and 1877 tsunamis in Southern Peru and Northern Chile

    NASA Astrophysics Data System (ADS)

    Morales, S.; Soto-Sandoval, J.; Monardez, P.

    2013-05-01

    The tsunami occurred on 27th February 2010 offshore central Chile due to a mega-thrust earthquake (Mw=8.8), showed a complex hydrodynamic behavior in the near field that is not completely understood and could not be well characterized using linear models (Cox 2011, Fujima 2011). Several floods separated by several minutes that lasted over eight hours, which flowed parallel to the coast were reported. A reasonable physical explication for this phenomena has been published. Due to the distance from the rupture zone to the coast is shorter than a complete tsunami wave, the latter cannot be created then secondary effects are triggered (Monárdez and Salinas, 2011). This was validated using numerical models based on RANS equations and measurements and field observations in the 2010 Chilean tsunami. Due to this knowledge, the 1868 and 1877 last mega-thrust earthquakes in the Southern Peru and Northern Chile are analyzed. This became necessary, since this zone is known as one the major seismic gap in the area. Scenarios with different fault parameters were implemented for the 1868 and 1877 tsunamis and important results were obtained. In both of the tsunamis, several floods were observed and the arrival time and direction of flow propagation were according to historical reports. In the 1868 tsunami, the effects on the Chilean coast are due to secondary effects such as it is described in historical observations, e.g. in Arica port three main floods 40, 120 and 156 minutes after the earthquakes are observed. In the 1877 tsunami secondary effects were present mainly on the Peruvian coast. Finally, a new classification for near and far field tsunami is proposed.

  19. Economic effect of bovine abortion syndrome in commercial dairy herds in Southern Chile.

    PubMed

    Gädicke, P; Vidal, R; Monti, G

    2010-10-01

    Bovine abortion is a limiting factor for dairy business, as it decreases milk production and the potential, number of herd replacements, increases feeding and medical treatment costs, increases the number of artificial inseminations to obtain a calf as well as culling rates of cows. An estimation of the economic impact of abortion in dairy farms in Chile is not available yet. The aim of this study was to estimate the economic consequences of bovine abortion syndrome (BAS) in dairy cows from Chile. A stochastic model was proposed to evaluate the cost of an abortion on a yearly basis to include variability in cost and income by dairy and by year. The marginal total net revenue (ΔTNR) for a typical, lactation was obtained by the calculating the difference between total revenues (retail milk and calf sales) and total expenses (production cost (cows, feeding, labor, health) plus administrative and, general costs) for lactation with and without abortion. Production data were obtained from a retrospective study of 127 dairy herds located in southern Chile between 2000 and 2006. Milk production from cows with and without abortion was estimated by a mixed model using milk test day data. Production cost and prices paid to farmers were obtained from service company records (TODOAGRO S.A.). Cost and income value was corrected for inflation and expressed in the values from 2006. In addition, a separate analysis for different parities (1, 2, 3 or more) was performed. Distributions for the stochastic variables were obtained by fitting distributions from our database using @Risk. The stochastic variables included in the analysis were all related to income, feeding, depreciation, health, Artificial Insemination and general costs like fuel, salaries, taxes, etc. There was a high probability (89.20%) of a negative ΔTNR in lactations with abortion for overall, parities, with a mean loss of $ -143.32. Stratifying by parity, the predicted mean of the distribution for ΔTNR in each

  20. Natural communities in catch basins in southern Rhode Island

    USGS Publications Warehouse

    Butler, M.; Ginsberg, H.S.; LeBrun, R.A.; Gettman, A.D.; Pollnak, F.

    2007-01-01

    Storm-water drainage catch basins are manmade structures that often contain water and organic matter, making them suitable environments for various organisms. We censused organisms inhabiting catch basins in southern Rhode Island in 2002 in an effort to begin to describe these communities. Catch-basin inhabitants were mostly detritivores, including annelids, arthropods, and mollusks that could withstand low oxygen levels and droughts. Our results suggest that catch-basin inhabitants were mostly washed in with rainwater, and populations increased over the summer season as biotic activity resulted in increased nutrient levels later in the summer. In contrast, mosquitoes and other Diptera larvae were abundant earlier in the summer because the adults actively sought catch basins for oviposition sites. Mosquito larvae were likely to be abundant in catch basins with shallow, stagnant water that had relatively low dissolved oxygen and pH, and relatively high total suspended solids, carbon, and nitrogen.

  1. Seismicity in the outer rise offshore southern Chile: Indication of fluid effects in crust and mantle

    NASA Astrophysics Data System (ADS)

    Tilmann, Frederik J.; Grevemeyer, Ingo; Flueh, Ernst R.; Dahm, Torsten; Goßler, Jürgen

    2008-05-01

    We examine the micro-earthquake seismicity recorded by two temporary arrays of ocean bottom seismometers on the outer rise offshore southern Chile on young oceanic plate of ages 14 Ma and 6 Ma, respectively. The arrays were in operation from December 2004-January 2005 and consisted of 17 instruments and 12 instruments, respectively. Approximately 10 locatable events per day were recorded by each of the arrays. The catalogue, which is complete for magnitudes above 1.2-1.5, is characterized by a high b value, i.e., a high ratio of small to large events, and the data set is remarkable in that a large proportion of the events form clusters whose members show a high degree of waveform similarity. The largest cluster thus identified consisted of 27 similar events (average inter-event correlation coefficient > 0.8 for a 9.5 s window), and waveform similarity persists far into the coda. Inter-event spacing is irregular, but very short waiting times of a few minutes are far more common than expected from a Poisson distribution. Seismicity with these features (high b value, large number of similar events with short waiting times) is typical of swarm activity, which, based on empirical evidence and theoretical considerations, is generally thought to be driven by fluid pressure variations. Because no pronounced outer rise bulge exists on the very young plate in the study region, it is unlikely that melt is accessible from decompression melting or opening of cracks. A fluid source related to processes at the nearby ridge is conceivable for the younger segment but less likely for the older one. We infer that the fluid source could be seawater, which enters through fractures in the crust. Most of the similar-earthquake clusters are within the crust, but some of them locate significantly below the Moho. If our interpretation is correct, this implies that water is present within the mantle. Hydration of the mantle is also indicated by a decrease of Pn velocities below the outer

  2. Two New Species of Prismatolaimus de Man, 1880 (Nemata: Prismatolaimidae) in Southern Chile

    PubMed Central

    Coomans, A. V.; Raski, D. J.

    1988-01-01

    Two new species of Prismatolaimus are described from Orange Bay, Hoste Island, Chile. Prismatolaimus novoporus sp. n. is distinguished by its females being 1.08-1.28 mm long and monovarial with a long postvulvar sac, and having a long tail (c' = 21.5-32.2); males have 11-20 supplements confined to the posterior part of the body. Prismatolaimus chilensis sp. n. is distinguished by its amphidelphic reproductive system, short tail (c' = 9.5), V = 63.4; males have 23 supplements reaching up to the neck region. A well-developed dorsal body pore behind the cardia connected with an apparently glandular organ is reported in P. novoporus sp. n. Function of the organ is unknown, and it is not a general feature in the genus. The generic diagnosis of Prismatolaimus is emended and keys to species, both females and males, are presented. The systematic position of Prismatolaimus is discussed, and it is judged to be the only genus of Prismatolaimidae. Also, it is concluded that Prismatolaimidae and Bastianidae represent two sister taxa in Araeolaimida or Leptolaimina. PMID:19290212

  3. Structure and Neotectonics of the Southern Chile Forearc 35°S - 40°S

    NASA Astrophysics Data System (ADS)

    Geersen, Jacob; Völker, David; Weinrebe, Wilhelm; Krastel-Gudegast, Sebastian; Behrmann, Jan H.

    2010-05-01

    The Southern Chile Forearc exhibits an extreme level of neotectonic deformation. On-land studies have documented a pronounced segmentation in the region 36°S - 41°S. However, information on the seaward continuation of the individual segments towards the Chile Trench is rare, as direct observations end at the coastline and are replaced by a less dense set of marine geophysical data. In this study we use swath bathymetric data combined with high and low-frequency reflection seismic data as well as results from heat-flow measurements to: (A) map and identify active deformation structures and investigate their spatial distribution, and (B) analyse the factors controlling segmentation along the Southern Chile Forearc. Considering the region 35°S to 40°S we found evidence for a division into four major segments; Concepcion North, Concepcion South, Nahuelbuta, and Tolten (from North to South). Within all four segments, the lower continental slope is dissected by distinct margin-parallel thrust ridges overlying active landward-dipping thrust faults, indicating the presence of an active accretionary prism. The middle and upper slope, however, shows major differences between the four segments. The Concepcion North Segment is dominated by a large margin-parallel thrust ridge. The Concepcion South Segment shows large up to 600 m high north-south aligned normal fault scarps highlighting east-west extension. The change from thrust to normal faulting domains is accompanied by a drastic decrease in surface heat-flow by a factor of up to four. Further south in the Nahuelbuta Segment, east-west trending active thrust ridges indicate north-south compression of this part of the forearc. Shortening in this segment is not only limited to the middle and upper slope, but includes the entire marine forearc and occurs perpendicular to the direction of plate convergence. In the southernmost Tolten Segment the middle and upper continental slope shows no signs of compressive or extensional

  4. Two new Liolaemus lizards from the Andean highlands of Southern Chile (Squamata, Iguania, Liolaemidae).

    PubMed

    Troncoso-Palacios, Jaime; Diaz, Hugo A; Puas, German I; Riveros-Riffo, Edvin; Elorza, Alvaro A

    2016-01-01

    Liolaemus is a diverse genus of lizards, subdivided into two subgenera: Liolaemus (sensu stricto) and Eulaemus, distributed mainly in Chile and Argentina. The Liolaemus elongatus-kriegi complex is the most diverse group within Liolaemus (sensu stricto), especially the species closely related to Liolaemus elongatus, which form a clade currently comprising nine species. Several Chilean species of this group have been recently described, mainly from volcanoes and poorly explored mountains. Here molecular and morphological evidence are provided for a new species of the Liolaemus elongatus clade, which is characterized by its small size and lack of dorsal pattern, unusual features for the species of this group of lizards. Additionally, the lack of precloacal pores in males of Liolaemus (sensu stricto) is a trait found in few species, which do not constitute a monophyletic group. A second new southern Chilean species is also described, without precloacal pores and supported by molecular phylogenetics to be related to Liolaemus villaricensis. Both new species were found in the same locality, near a lake located in a pre-Andean zone with Araucaria and Nothofagus forest. The two species are dedicated to prominent Lonkos (tribal chiefs) of the Mapuche and Pehuenche people: Janequeo and Leftraru. Additionally, the phylogenetic results suggest that Liolaemus lonquimayensis is a synonym of Liolaemus elongatus.

  5. Isolation of Helicobacter pylori in gastric mucosa and susceptibility to five antimicrobial drugs in Southern chile

    PubMed Central

    Otth, Laura; Wilson, Myra; Fernández, Heriberto; Otth, Carola; Toledo, Claudio; Cárcamo, Victoria; Rivera, Paula; Ruiz, Luis

    2011-01-01

    Helicobacter pylori colonizes more than 50% of the world population thus, it is considered an important cause of gastric cancer. The aim of this study was to determine the isolation frequency of H. pylori in Southern Chile from patients with symptomatology compatible with gastritis or gastric ulcer and to correlate these findings with demographic parameters of infected patients and the susceptibility profiles of the isolated strains to the antimicrobial drugs used in the eradication treatments. A total of 240 patients were enrolled in the study. Each gastric biopsy was homogenized and seeded onto blood agar plates containing a selective antibiotics mixture (DENT supplement). Plates were incubated at 37° C in a microaerophilic environment for five days. The susceptibility profiles to amoxicillin, ciprofloxacin, clarithromycin, tetracycline and metronidazole were determined using the E-test method. H. pylori was isolated from 99 patients (41.3%) with slightly higher frequency in female (42% positive cultures) than male (40.2% positive cultures). With regard to age and educational level, the highest isolation frequencies were obtained in patients between 21–30 (55%) and 41–50 (52.6%) years old, and patients with secondary (43.9%) and university (46.2%) educational levels. Nineteen (21.6%) strains showed resistance to at least one antimicrobial drug. Tetracycline was the most active antimicrobial in vitro, whereas metronidazole was the less active. One strain (5.3%) showed resistance to amoxicillin, clarithomycin and metronidazole, simultaneously. PMID:24031652

  6. Patagonian fjord ecosystems in southern Chile as a highly vulnerable region: problems and needs.

    PubMed

    Iriarte, Jose Luis; González, Humberto E; Nahuelhual, Laura

    2010-11-01

    Southern Chile encompasses one of the most extensive fjord regions of the world, the Patagonia, currently exposed to natural and anthropogenic perturbations. These fjord ecosystems provide important services to humans, which have not been adequately measured and valued. As a consequence, ecosystem services are commonly ignored in public policy design and in the evaluation of development projects. Here we tackle questions that are highly relevant for the nation's development, namely (1) understanding fjord functioning, and (2) developing management strategies based on ecosystem services, in order to secure simultaneous and adequate use of these ecosystems which area influenced by ecological (e.g., biogeochemical) and productive (e.g., aquaculture, fisheries) processes. We also seek to strengthen the analysis of fjord ecosystem value from the economical (including coastal zoning), socio-cultural, institutional, and governmental points of view. In addition, the investigation of current and future effects of climate change on this large region offers a unique opportunity to understand the social and economic consequences of a global phenomenon at local to regional scales. Biogeochemical and socio-economic models will be used to simulate future scenarios under a gamut of management options.

  7. Two new Liolaemus lizards from the Andean highlands of Southern Chile (Squamata, Iguania, Liolaemidae)

    PubMed Central

    Troncoso-Palacios, Jaime; Diaz, Hugo A.; Puas, German I.; Riveros-Riffo, Edvin; Elorza, Alvaro A.

    2016-01-01

    Abstract Liolaemus is a diverse genus of lizards, subdivided into two subgenera: Liolaemus (sensu stricto) and Eulaemus, distributed mainly in Chile and Argentina. The Liolaemus elongatus-kriegi complex is the most diverse group within Liolaemus (sensu stricto), especially the species closely related to Liolaemus elongatus, which form a clade currently comprising nine species. Several Chilean species of this group have been recently described, mainly from volcanoes and poorly explored mountains. Here molecular and morphological evidence are provided for a new species of the Liolaemus elongatus clade, which is characterized by its small size and lack of dorsal pattern, unusual features for the species of this group of lizards. Additionally, the lack of precloacal pores in males of Liolaemus (sensu stricto) is a trait found in few species, which do not constitute a monophyletic group. A second new southern Chilean species is also described, without precloacal pores and supported by molecular phylogenetics to be related to Liolaemus villaricensis. Both new species were found in the same locality, near a lake located in a pre-Andean zone with Araucaria and Nothofagus forest. The two species are dedicated to prominent Lonkos (tribal chiefs) of the Mapuche and Pehuenche people: Janequeo and Leftraru. Additionally, the phylogenetic results suggest that Liolaemus lonquimayensis is a synonym of Liolaemus elongatus. PMID:27920609

  8. Total factor productivity change in dairy farming: Empirical evidence from southern Chile.

    PubMed

    Moreira, Víctor H; Bravo-Ureta, Boris E

    2016-10-01

    Despite the importance of productivity growth, many studies carried out at the farm level focus primarily on the technical efficiency (TE) component of farm productivity. Therefore, the general purpose of this paper is to measure total factor productivity change and then to decompose this change into several distinct elements. The data were an unbalanced panel for the period from 2005 to 2010 containing 477 farms and 1,426 observations obtained from TODOAGRO, a farm-management center created in 1996 in the southern part of Chile. The region where the data come from accounts for 20% of the total milk processed in the country. Stochastic production frontiers along with the translog functional form were used to analyze total factor productivity change. The econometric evidence indicates that farms exhibit decreasing returns to size implying that costs of production rise as farm size increases, which suggests that the motivation for farm growth stems from the search for income rather than from lowering costs. The main results indicated that productivity gains through TE improvements are limited, with an average TE for the whole sample of 91.0%, and average technical efficiency change of 0.05% per year. By contrast, average technological progress at the sample mean was rather high at 1.90%, which suggests that additional investments in research and subsequent adoption of improved technologies would have a positive effect on productivity growth. The findings also revealed that farm size is not associated with productivity growth for the dairy farms in the sample.

  9. Glaciovolcanism at Volcán Sollipulli, southern Chile: Lithofacies analysis and interpretation

    NASA Astrophysics Data System (ADS)

    Lachowycz, Stefan M.; Pyle, David M.; Gilbert, Jennie S.; Mather, Tamsin A.; Mee, Katy; Naranjo, José A.; Hobbs, Laura K.

    2015-09-01

    Magma-ice-meltwater interactions produce diverse landforms and lithofacies, reflecting the multitude of factors that influence glaciovolcanism, including both magmatic (e.g., composition, eruption rate) and glacial (e.g., ice thickness, thermal regime) conditions. This is exemplified by the walls of the partly ice-filled summit caldera of Volcán Sollipulli, a stratovolcano in southern Chile, which include lithofacies from eruptions of a wide range of magma compositions beneath or in contact with ice. Here we analyse these lithofacies and hence propose new interpretations of the eruptive and glacial history of Sollipulli. The facies include a thick, laterally extensive sequence of fragmental glaciovolcanic deposits, comprising massive, mafic lava pillow-bearing hyaloclastite overlain by sills and then hyaloclastic debris flow deposits (similar to Dalsheidi-type sequences). The distribution and thickness of these units indicate an unusual abundance of magma-meltwater interaction for an arc stratovolcano in temperate latitudes, perhaps due to eruptions beneath a thick ice cap. Coherent lava coulées, domes, lobes, and stacks of basaltic andesite-trachydacite composition are present around the top of the caldera rim; these display morphologies and fracture patterns on caldera-facing margins that indicate that the caldera was filled with ice when these lavas were erupted. The lithofacies characterised in this study demonstrate the diversity of glaciovolcanism that is possible at arc stratovolcanoes capped by temperate ice or with ice-filled calderas, and the potential for uncertainties in inference of the palaeoenvironmental conditions of their emplacement.

  10. Phylogenetic Diversity of Peltigera Cyanolichens and Their Photobionts in Southern Chile and Antarctica.

    PubMed

    Zúñiga, Catalina; Leiva, Diego; Ramírez-Fernández, Lía; Carú, Margarita; Yahr, Rebecca; Orlando, Julieta

    2015-01-01

    The lichen genus Peltigera has been mainly revised in the Northern Hemisphere, with most species being recorded in Europe and North America. This study assessed the phylogenetic diversity of the mycobionts and cyanobionts of Peltigera cyanolichens collected in Southern Chile and Antarctica, areas in which lichens are extremely diverse but poorly studied. The operational taxonomic units (OTUs) of each symbiont were defined by analyzing the genetic diversity of the LSU and SSU rDNA of the mycobionts and cyanobionts, respectively, and a phylogenetic approach was used to relate these OTUs with sequences previously reported for Peltigera and Nostoc. Among the 186 samples collected, 8 Peltigera and 15 Nostoc OTUs were recognized, corresponding to sections Peltigera, Horizontales, and Polydactylon, in the case of the mycobionts, and to the Nostoc clade II, in the case of the cyanobionts. Since some of the OTUs recognized in this study had not previously been described in these areas, our results suggest that the diversity of Peltigera reported to date in the regions studied using traditional morphological surveys has underestimated the true diversity present; therefore, further explorations of these areas are recommended.

  11. Leptospira contamination in household and environmental water in rural communities in southern Chile.

    PubMed

    Muñoz-Zanzi, Claudia; Mason, Meghan R; Encina, Carolina; Astroza, Angel; Romero, Alex

    2014-06-26

    Leptospirosis is a zoonosis of global distribution that affects tropical and temperate areas. Under suitable conditions, Leptospira can survive in water and soil and contribute to human and animal infections. The objective of this study was to describe the presence of pathogenic Leptospira in peri-domestic water samples from rural households in southern Chile. Water samples, including puddles, containers, animal troughs, rivers, canals, and drinking water were collected from 236 households and tested for Leptospira using a PCR assay targeting the lipL32 gene. Evidence of Leptospira presence was detected in all sample types; overall, 13.5% (77/570) samples tested positive. A total of 10/22 (45.5%) open containers, 12/83 (14.5%) animal drinking sources, 9/47 (19.1%) human drinking sources, and 36/306 (19.3%) puddles tested positive. Lower income (OR = 4.35, p = 0.003), increased temperature (OR = 1.23, p < 0.001), and presence of dogs (OR = 15.9, p = 0.022) were positively associated with positive puddles. Increased number of rodent signs was associated with positive puddles in the household (OR = 3.22); however, only in the lower income households. There was no association between PCR positive rodents and puddles at the household level. Results revealed the ubiquity of Leptospira in the household environment and highlight the need to develop formal approaches for systematic monitoring.

  12. Seiche excitation in a highly stratified fjord of southern Chile: the Reloncaví fjord

    NASA Astrophysics Data System (ADS)

    Castillo, Manuel I.; Pizarro, Oscar; Ramírez, Nadin; Cáceres, Mario

    2017-02-01

    We describe a seiche process based on current, temperature, and sea-level data obtained from the Reloncaví fjord (41.6° S, 72.5° W) in southern Chile. We combined 4 months of acoustic Doppler current profiler (ADCP) data with sea-level, temperature, and wind time series to analyze the dynamics of low-frequency (periods > 1 day) internal oscillations in the fjord. Additionally, seasonal conductivity, temperature, and depth (CTD) data from 19 along-fjord stations were used to characterize the seasonality of the density field. The density profiles were used to estimate the internal long-wave phase speed (c) using two approximations: (1) a simple reduced gravity model (RGM) and (2) a continuously stratified model (CSM). No major seasonal changes in c were observed using either approximation (e.g., the CSM yielded 0.73 < c < 0.87 m s-1 for mode 1). The natural internal periods (TN) were estimated using Merian's formula for a simple fjord-like basin and the above phase speeds. Estimated values of TN varied between 2.9 and 3.5 days and were highly consistent with spectral peaks observed in the along-fjord currents and temperature time series. We conclude that these oscillations were forced by the wind stress, despite the moderate wind energy. Wind conditions at the end of winter gave us an excellent opportunity to explore the damping process. The observed damping time (Td) was relatively long (Td = 9.1 days).

  13. Phylogenetic Diversity of Peltigera Cyanolichens and Their Photobionts in Southern Chile and Antarctica

    PubMed Central

    Zúñiga, Catalina; Leiva, Diego; Ramírez-Fernández, Lía; Carú, Margarita; Yahr, Rebecca; Orlando, Julieta

    2015-01-01

    The lichen genus Peltigera has been mainly revised in the Northern Hemisphere, with most species being recorded in Europe and North America. This study assessed the phylogenetic diversity of the mycobionts and cyanobionts of Peltigera cyanolichens collected in Southern Chile and Antarctica, areas in which lichens are extremely diverse but poorly studied. The operational taxonomic units (OTUs) of each symbiont were defined by analyzing the genetic diversity of the LSU and SSU rDNA of the mycobionts and cyanobionts, respectively, and a phylogenetic approach was used to relate these OTUs with sequences previously reported for Peltigera and Nostoc. Among the 186 samples collected, 8 Peltigera and 15 Nostoc OTUs were recognized, corresponding to sections Peltigera, Horizontales, and Polydactylon, in the case of the mycobionts, and to the Nostoc clade II, in the case of the cyanobionts. Since some of the OTUs recognized in this study had not previously been described in these areas, our results suggest that the diversity of Peltigera reported to date in the regions studied using traditional morphological surveys has underestimated the true diversity present; therefore, further explorations of these areas are recommended. PMID:25925273

  14. Isolation of Helicobacter pylori in gastric mucosa and susceptibility to five antimicrobial drugs in Southern chile.

    PubMed

    Otth, Laura; Wilson, Myra; Fernández, Heriberto; Otth, Carola; Toledo, Claudio; Cárcamo, Victoria; Rivera, Paula; Ruiz, Luis

    2011-04-01

    Helicobacter pylori colonizes more than 50% of the world population thus, it is considered an important cause of gastric cancer. The aim of this study was to determine the isolation frequency of H. pylori in Southern Chile from patients with symptomatology compatible with gastritis or gastric ulcer and to correlate these findings with demographic parameters of infected patients and the susceptibility profiles of the isolated strains to the antimicrobial drugs used in the eradication treatments. A total of 240 patients were enrolled in the study. Each gastric biopsy was homogenized and seeded onto blood agar plates containing a selective antibiotics mixture (DENT supplement). Plates were incubated at 37° C in a microaerophilic environment for five days. The susceptibility profiles to amoxicillin, ciprofloxacin, clarithromycin, tetracycline and metronidazole were determined using the E-test method. H. pylori was isolated from 99 patients (41.3%) with slightly higher frequency in female (42% positive cultures) than male (40.2% positive cultures). With regard to age and educational level, the highest isolation frequencies were obtained in patients between 21-30 (55%) and 41-50 (52.6%) years old, and patients with secondary (43.9%) and university (46.2%) educational levels. Nineteen (21.6%) strains showed resistance to at least one antimicrobial drug. Tetracycline was the most active antimicrobial in vitro, whereas metronidazole was the less active. One strain (5.3%) showed resistance to amoxicillin, clarithomycin and metronidazole, simultaneously.

  15. Pelagic resources landings in central-southern Chile under the A2 climate change scenarios

    NASA Astrophysics Data System (ADS)

    Yáñez, Eleuterio; Plaza, Francisco; Silva, Claudio; Sánchez, Felipe; Barbieri, María Ángela; Aranis, Antonio

    2016-10-01

    Artificial neural networks (ANNs) were used to predict landings of anchovy ( Engraulis ringens), common sardine ( Strangomera bentincki), and jack mackerel ( Trachurus murphyi) in central-southern Chile. Twelve environmental variables were considered along with fishing effort (fe) and landing statistics from 1973 to 2012. During external validation, the best models with all of the selected variables gave r 2 values of 90 % for anchovy, 96 % for common sardine, and 88 % for jack mackerel. The models were simplified by considering only fe and sea surface temperature from NCEP/NCAR reanalysis data (SST-NOAA), and very similar fits were achieved (87, 92, and 88 %, respectively). Future SSTs were obtained from the A2 climate change scenario and regionalized using statistical downscaling techniques. The downscaled SSTs were used as input for landings predictions using ANN simplified models. In addition, three scenarios of future fishing efforts (2010-2012 average, average + 50 %, and average - 50 %) were used as the input data for landing simulations. The results of the predictions show a decrease of 9 % in future landings of sardine and an increase of 17 % for jack mackerel when comparing 2015 and 2065 monthly projections. However, no significant differences are shown when comparing the estimated landings for the three fishing effort scenarios. Finally, more integrative and complex conceptual models that consider oceanographic-biophysical, physiological, environmental-resource, and interspecies processes need to be implemented.

  16. Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

    NASA Astrophysics Data System (ADS)

    Bahlburg, H.; Breitkreuz, C.

    The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

  17. Earthquakes in Fiordland, Southern Chile: Initiation and Development of a Magmatic Process

    NASA Astrophysics Data System (ADS)

    Barrientos, S.; Service, N. S.

    2007-05-01

    Several efforts in Chile are being conducted in relation to geophysical monitoring with the objective of disaster mitigation. A long and permanent monitoring effort along the country has been the continuous effort resulting in the recognition and delineation of new seismogenic sources. Here we report on the seismo-volcanic crisis that is currently taking place in the in the region close to the triple junction (Nazca, Antarctica and South America) in southern Chile at around latitude 45°S. On January 22, 2007, an intensity V-VI (MMI) earthquake shook the cities of Puerto Aysén, Puerto Chacabuco and Coyhaique. This magnitude 5 event, was the first of a series of earthquakes that have taken place in the region for nearly a month and a half (until end of February, time when this abstract was written). The closest station to the source area -part of the GEOSCOPE network located in Coyhaique, about 80 km away from the epicenters- reveals seismic activity about 3 hours before the first event. Immediately after the first event, more than 20 events per hour were detected and recorded by this station, rate which decreased with time with the exception of those time intervals following larger events. More than six events with magnitude 5 or more have been recorded. Five seismic stations were installed surrounding the epicentral area between 27 - 29 January and are currently operational. After processing some of the recorded events, a sixth station was installed at the closest possible site of the source of the seismic activity. Preliminary analysis of the recorded seismic activity reveals a concentration of hypocenters - 5 to 10 km depth- along an eight-km NNE-SSW vertical plane crossing the Aysén fiord. Harmonic tremor has also been detected. This seismic activity is interpreted as the result of a magmatic process in progress which will most likely culminate in the generation of a new underwater volcanic edifice. Because the seismic activity fully extends across the Ays

  18. Genetic variation (AFLPs and nuclear microsatellites) in two anagenetically derived endemic species of Myrceugenia (Myrtaceae) on the Juan Fernández Islands, Chile.

    PubMed

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

    2013-04-01

    Anagenesis (or phyletic evolution) is one mode of speciation that occurs in the evolution of plants on oceanic islands. Of two endemic species on the Juan Fernández Islands (Chile), Myrceugenia fernandeziana and M. schulzei (Myrtaceae), believed to have originated anagenetically from different continental progenitors, the first is endemic to Robinson Crusoe Island and has no clear tie to continental relatives; the last is endemic to the younger island, Alejandro Selkirk Island, and has close affinity to M. colchaguensis in mainland Chile. Using AFLPs and six nuclear microsatellites from 381 individuals representing 33 populations, we determined patterns of genetic variation within and among populations on both islands and between those of the islands and mainland. Considerable genetic variation was found within populations on both islands. The level of gene diversity within M. schulzei was equivalent to that of its close continental relative M. colchaguensis. Genetic diversity was not partitioned geographically in M. fernandeziana and was weakly so and nonsignificantly in M. schulzei. The high genetic variation in both taxa is most likely due to anagenetic speciation. Subsidence of the older island Robinson Crusoe, landscape erosion, and restructuring of communities have severely reduced the overall island population to a single panmictic system. On the younger and less modified Alejandro Selkirk Island, slightly stronger patterns of genetic divergence are seen in M. schulzei. Because both species are genetically diverse and number in the thousands of individuals, neither is presently endangered in the archipelago.

  19. Tectonic implications of a paleomagnetic study of the Sarmiento Ophiolitic Complex, southern Chile

    NASA Astrophysics Data System (ADS)

    Rapalini, A. E.; Calderón, M.; Singer, S.; Hervé, F.; Cordani, U.

    2008-06-01

    A paleomagnetic study was carried out on the Late Jurassic Sarmiento Ophiolitic Complex (SOC) exposed in the Magallanes fold and thrust belt in the southern Patagonian Andes (southern Chile). This complex, mainly consisting of a thick succession of pillow-lavas, sheeted dikes and gabbros, is a seafloor remnant of the Late Jurassic to Early Cretaceous Rocas Verdes basin that developed along the south-western margin of South America. Stepwise thermal and alternating field demagnetization permitted the isolation of a post-folding characteristic remanence, apparently carried by fine grain (SD?) magnetite, both in the pillow-lavas and dikes. The mean "in situ" direction for the SOC is Dec: 286.9°, Inc: - 58.5°, α95: 6.9°, N: 11 (sites). Rock magnetic properties, petrography and whole-rock K-Ar ages in the same rocks are interpreted as evidence of correlation between remanence acquisition and a greenschist facies metamorphic overprint that must have occurred during latest stages or after closure and tectonic inversion of the basin in the Late Cretaceous. The mean remanence direction is anomalous relative to the expected Late Cretaceous direction from stable South America. Particularly, a declination anomaly over 50° is suggestively similar to paleomagnetically interpreted counter clockwise rotations found in thrust slices of the Jurassic El Quemado Fm. located over 100 km north of the study area in Argentina. Nevertheless, a significant ccw rotation of the whole SOC is difficult to reconcile with geologic evidence and paleogeographic models that suggest a narrow back-arc basin sub-parallel to the continental margin. A rigid-body 30° westward tilting of the SOC block around a horizontal axis trending NNW, is considered a much simpler explanation, being consistent with geologic evidence. This may have occurred as a consequence of inverse reactivation of old normal faults, which limit both the SOC exposures and the Cordillera Sarmiento to the East. The age of tilting

  20. Potential landslide activity affecting the archaeological site of Orongo (Easter Island-Chile): preliminary analysis

    NASA Astrophysics Data System (ADS)

    Margottini, C.; Delmonaco, G.; Spizzichino, D.; Pandolfi, O.; Crisostomo, R.; Nohe, S.

    2009-04-01

    Easter Island forms part of the Easter Line, a continuous latitudinal chain of volcanic seamounts and islands in the Pacific Sea. The island's roughly triangular shape is determined by the merging of lava flows produced by its three main volcanoes (Rano Kau, Terevaka, Poike) which form its main mass. The Rano Kau volcano, sited in the SW vertex of the island, is made up of numerous basaltic lava flows and has been reduced in size by faulting and marine erosion. Its crater (1.4 km wide) is a small caldera that collapsed after a late, large explosive phase, as attested by the presence of breccia deposits around the eastern rim of the crater. The archaeological stone village of Orongo is located above the inner wall of the crater at an altitude of ca. 300m a.s.l. Prominent historical remains are the numerous petroglyphs that represent the ancient ceremonial of the birdman cult (tangata manu). Rano Kau is mainly composed of sequences of basaltic and intermediate lavas and pyroclastics. Most of the of the original caldera area, especially in the southern flank, has been disrupted by marine erosion. This has caused a dramatic change of the original morphology, resulting in a sub-vertical cliff and steep slopes, especially in the middle-low portions. In the upper part of the slopes weathered soils and regolith are outcropping. Topographical and geomorphological analysis of the area conducted by a direct field surveys in January and July 2008 have provided clear evidences of slope instability along the southern external flank of the caldera. Different landslide areas have been detected. The most active area is located at east of the village in correspondence of the crest zone of Rano Kau where a debris slide/fall has recently occurred. The analysis of photos taken in Nov. 2007 in the same area evidences that the landslide crown area was originated at an elevation of ca. 200m a.s.l. along a probable contact between basaltic layers on the top and weathered lava. Other minor

  1. Hurricane Sandy Washover Deposits on Southern Long Beach Island, NJ

    NASA Astrophysics Data System (ADS)

    Bishop, J. M.; Richmond, B. M.; Kane, H. H.; Lunghino, B.

    2015-12-01

    Hurricane Sandy washover deposits were investigated at Forsyth National Wildlife Refuge (FNWR) on Southern Long Beach Island, New Jersey in order to map deposit thickness and characterize the sedimentary deposits. FNWR was chosen as a field area because there has been relatively little anthropogenic shoreline modification since washover deposition from Hurricane Sandy. Sediment, elevation, and geophysical data were collected during the April 2015 field campaign, approximately two and a half years after the storm. Sediment deposit data included trenches, stratigraphic descriptions, bulk sediment samples, push cores, Russian cores, and photos. Computed tomography (CT) scanning was conducted on push cores in order to acquire high resolution imaging of density, grain size, and sedimentary structure. Profiles of washover elevation were measured using Differential GPS with Real Time Kinematic processing. Ground Penetrating Radar data was collected to image the depth of the deposit and identify sedimentary structures. These data sets are compared to pre- and post -Sandy lidar surveys in order to determine post-Sandy modification in the two and a half years following the hurricane. We compare sediment thickness and sedimentary characteristics to hurricane Sandy deposits elsewhere along the U.S. eastern seaboard and to tsunami deposits.

  2. The Seismogenic Zone in Southern Chile: Insights from high resolution receiver function analysis and seismic Tomography

    NASA Astrophysics Data System (ADS)

    Rietbrock, A.; Haberland, C.; Lange, D.; Bataille, K.

    2004-12-01

    Subduction zones, the expression of convergent plate boundaries, generate the world's largest and most destructive earthquakes. The Southern Chilean subduction zone is an ideal natural laboratory to study the processes involved in generating these devastat- ing earthquakes and is one of the main aims of the international and interdisciplinary research initiative TIPTEQ (from The Incoming Plate to megaThrust EarthQuake pro- cesses). High resolution images, using different techniques as well as different physi- cal parameters, form the base for identifying the processes involved. Here we present new data from teleseismic receiver function analysis and 3D seismic tomography to study in detail the down-dip end of the seismogenic zone in the nucleation area of the 1960 magnitude Mw=9.5 Valdivia, Chile, earthquake. Within the project TIPTEQ two dense amphibious passive seismic networks have been installed between Nov. 2004 and Oct. 2005, both covering the entire forearc from the trench to the active volcanic front. The Northern array was located between 37° and 39° South including the epicentre of the 1960 Chile earthquake. It consisted out of 120 continuously recording, three component stations on land and 10 continuously recording Ocean Bottom Seismometers/Hydrophones (OBS/H) at sea. The Southern array was located between 41.5° and 43.5° South roughly in the middle of the rupture zone of the Valdivia earthquake. It consisted out of 20 continuously recording three component stations on land and 20 continuously recording Ocean Bottom Seismometers/Hydrophones (OBS/H) at sea. Several hundreds of micro earthquakes could be located using manual picked P- and S-wave arrivals. Joint 2D/3D inversions for earthquake location, P-wave velocity and vp/vs-ratio were carried out and give a detailed image of the structure as well as a snapshot of the seismicity distribution in both study regions. The subducting Nazca plate can be clearly identified in both regions dipping at a

  3. The Seismogenic Zone in Southern Chile: Insights from high resolution receiver function analysis and seismic Tomography

    NASA Astrophysics Data System (ADS)

    Rietbrock, A.; Haberland, C.; Lange, D.; Bataille, K.

    2007-12-01

    Subduction zones, the expression of convergent plate boundaries, generate the world's largest and most destructive earthquakes. The Southern Chilean subduction zone is an ideal natural laboratory to study the processes involved in generating these devastat- ing earthquakes and is one of the main aims of the international and interdisciplinary research initiative TIPTEQ (from The Incoming Plate to megaThrust EarthQuake pro- cesses). High resolution images, using different techniques as well as different physi- cal parameters, form the base for identifying the processes involved. Here we present new data from teleseismic receiver function analysis and 3D seismic tomography to study in detail the down-dip end of the seismogenic zone in the nucleation area of the 1960 magnitude Mw=9.5 Valdivia, Chile, earthquake. Within the project TIPTEQ two dense amphibious passive seismic networks have been installed between Nov. 2004 and Oct. 2005, both covering the entire forearc from the trench to the active volcanic front. The Northern array was located between 37° and 39° South including the epicentre of the 1960 Chile earthquake. It consisted out of 120 continuously recording, three component stations on land and 10 continuously recording Ocean Bottom Seismometers/Hydrophones (OBS/H) at sea. The Southern array was located between 41.5° and 43.5° South roughly in the middle of the rupture zone of the Valdivia earthquake. It consisted out of 20 continuously recording three component stations on land and 20 continuously recording Ocean Bottom Seismometers/Hydrophones (OBS/H) at sea. Several hundreds of micro earthquakes could be located using manual picked P- and S-wave arrivals. Joint 2D/3D inversions for earthquake location, P-wave velocity and vp/vs-ratio were carried out and give a detailed image of the structure as well as a snapshot of the seismicity distribution in both study regions. The subducting Nazca plate can be clearly identified in both regions dipping at a

  4. Urban dogs in rural areas: Human-mediated movement defines dog populations in southern Chile.

    PubMed

    Villatoro, Federico J; Sepúlveda, Maximiliano A; Stowhas, Paulina; Silva-Rodríguez, Eduardo A

    2016-12-01

    Management strategies for dog populations and their diseases include reproductive control, euthanasia and vaccination, among others. However, the effectiveness of these strategies can be severely affected by human-mediated dog movement. If immigration is important, then the location of origin of dogs imported by humans will be fundamental to define the spatial scales over which population management and research should apply. In this context, the main objective of our study was to determine the spatial extent of dog demographic processes in rural areas and the proportion of dogs that could be labeled as immigrants at multiple spatial scales. To address our objective we conducted surveys in households located in a rural landscape in southern Chile. Interviews allowed us to obtain information on the demographic characteristics of dogs in these rural settings, human influence on dog mortality and births, the localities of origin of dogs living in rural areas, and the spatial extent of human-mediated dog movement. We found that most rural dogs (64.1%) were either urban dogs that had been brought to rural areas (40.0%), or adopted dogs that had been previously abandoned in rural roads (24.1%). Some dogs were brought from areas located as far as ∼700km away from the study area. Human-mediated movement of dogs, especially from urban areas, seems to play a fundamental role in the population dynamics of dogs in rural areas. Consequently, local scale efforts to manage dog populations or their diseases are unlikely to succeed if implemented in isolation, simply because dogs can be brought from surrounding urban areas or even distant locations. We suggest that efforts to manage or study dog populations and related diseases should be implemented using a multi-scale approach. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Distribution of siphonophores, chaetognaths, euphausiids and oceanographic conditions in the fjords and channels of southern Chile

    NASA Astrophysics Data System (ADS)

    Palma, Sergio; Silva, Nelson

    2004-03-01

    Interior waters of the fjords and channels of southern Chile (41.5°S-56°S) receive inputs of Subantarctic Water, Equatorial Subsuperficial Water and Western Pacific Subsurface Water from the adjacent Pacific Ocean by means of numerous connecting channels that lead inward from the ocean margin. These waters become mixed in the interior zone with freshwater from precipitation, river flow, and meltwater from cordilleran glaciers. A two-layered positive estuarine circulation becomes established, with a superficial layer having a net movement towards the adjacent ocean, and a deep layer with net movement towards the fjords. The biomass of the interior waters is composed principally of planktonic crustaceans (copepods and euphausiids), chaetognaths, and gelatinous carnivores. In a southerly direction, decreases are observed in biomass, in relative abundance, and in species diversity of siphonophores, chaetognaths, and euphausiids. Only a few species have been able to adapt successfully to the extreme oceanographic conditions typical of the region, reflected in dominant monospecific populations such as Muggiaea atlantica, Sagitta tasmanica, and Euphausia vallentini. The zooplankton fauna of interior waters, characterized by its low degree of specific richness, is made up of a mixture of species typical of Subantarctic Water (Sagitta tasmanica, S. decipiens, Euphausia lucens, Nematoscelis megalops, Thysanoessa gregaria), antarctic water (Pyrosthephos vanhoeffeni, Dimophyes arctica, Sagitta marri, S. gazellae, Eukrohnia hamata, E. bathyantarctica, Euphausia vallentini), temperate and warm epipelagic waters (Eudoxoides spiralis, Lensia conoidea, Chelophyes appendiculata, Muggiaea atlantica, Sphaeronectes gracilis, S. fragilis, Abylopsis tetragona, Sagitta enflata), and mesopelagic water (Physophora hydrostatica, Stylocheiron maximum, Vogtia pentacantha, V. serrata).

  6. Post-earthquake coastal evolution and recovery of an embayed beach in central-southern Chile

    NASA Astrophysics Data System (ADS)

    Martínez, Carolina; Rojas, Daniel; Quezada, Matías; Quezada, Jorge; Oliva, Ricardo

    2015-12-01

    Earthquakes and tsunamis are significant factors for change along active margin shores, and influence coastal evolution. The Chilean coast was affected in 2010 by a subduction earthquake with a magnitude of Mw 8.8 and also by a trans-Pacific tsunami, which generated violent geomorphologic changes and damaged homes. Following these events, the magnitude of the changes which affect Chile's central-southern coast (37°S) and the role of subduction earthquakes in coastal evolution on a historical scale were investigated. At Lebu bay (an embayed beach) data were generated for variations in time and space along the shoreline, topographical and bathymetric changes in the bay, and for morphodynamic littoral processes. Logarithmic and parabolic models were applied to the shoreline along with map overlays in order to determine changes. The shoreline processes were analyzed based on statistics for waves, tides and sediment transport for pre- and post-tsunami conditions. An average accretion rate of 2.80 m/year (1984-2010) was established for the shoreline, with a strong trend towards accretion in the last 30 years. A parabolic function best represented the general form of the shoreline, although the presence of a river in the concave zone affected the fit in this sector. Two factors controlled historical changes on the beach: one of anthropic origin in addition to the earthquake and tsunami on February 27th, 2010. The post-earthquake recovery was fast, and currently the beach is in a stable condition despite the inter-seismic subsidence process previous to the event. This coastal system showed a high resilience in the face of coastal geomorphological changes induced by high-impact natural disturbances. However, the opposite occurred in relation to changes induced by anthropogenic disturbances.

  7. Actinian dominated intertidal mudflats: A new case of an extraordinary rare phenomenon from Southern Chile

    NASA Astrophysics Data System (ADS)

    Schories, Dirk; Reise, Karsten; Sanamyan, Karen; Sanamyan, Nadya; Clasing, Elena; Reise, Anneken

    2011-02-01

    Generally, estuarine intertidal mudflats constitute important nurseries for fish and foraging grounds for coastal birds by providing a plenitude of mollusks, worms, and crustaceans as prey, which in turn mostly feed on suspended and benthic microalgae, bacteria, and detritus. Despite the high productivity of such habitats, pronounced variability in both salinity and temperature results typically in low diversity. The only sea anemone reported from estuarine mud is the edwardsiid Nematostella vectensisStephenson, 1935. It occurs widely in the northern hemisphere, and occasionally in extremely high density. Here we document another sea anemone from estuarine mud and muddy sand found in Southern Chile which has similar ecological attributes. Taxonomic confusion has impeded the reporting on this small but prominent member in a macrozoobenthic assemblage, the brooding Anthopleura hermaphroditica (Carlgren, 1899; Anthozoa: Actiniidae). It differs from N. vectensis by the presence of symbiotic algae. Average density under poly- to euhaline conditions in mud and muddy sand at around mid tide level was about 3 actinians per cm 2. An average abundance of 11,000 m - 2 , a biovolume of 487 cm 3 m - 2 , and a biomass of 35.5 g dry organic weight m - 2 were found in mud and muddy sand in two surveys 20 years apart. The mean fishing area of fully expanded individuals covers 42 ± 25 mm 2, corresponding to a circular area with a diameter of 7.3 ± 5.7 mm. Preliminary experiments indicate that associated benthos may be relegated to life below surface by the net of tentacles above the sediment. As no predators on A. hermaphroditica could be found on the mudflat, the success of this mixotrophic sea anemone may entail a trophic dead end.

  8. Incidence of Metamorphism on Magnetic Mineralogy in the Sarmiento Ophiolitic Complex, Southern Chile

    NASA Astrophysics Data System (ADS)

    Singer, S.; Rapalini, A.; Calderon, M.; Herve, F.

    2005-05-01

    The Sarmiento Ophiolitic Complex (SOC), located in the southern Andes of Chile, represents the mafic portion of the Late Jurassic to Early Cretaceous oceanic floor of a back-arc basin closed and uplifted in the Mid Cretaceous. Its igneous pseudostratigraphy consists of mainly mafic pillow lavas, dikes, and gabbros. These rocks underwent a non - deformative "ocean floor metamorphism" which developed secondary mineral assemblages in a vertical steep metamorphic gradient passing from zeolite to actinolite facies, followed by a transition to fresh gabbros Syntectonic greenschist facies assemblages in mylonitic rocks bordering the thrust slices that expose the SOC, represent a different metamorphic event, that probably occured before the latest Cretaceous. A paleomagnetic study of these rocks has shown that a post-tectonic widespread remagnetization affected the whole ophiolite. Incidence of the mentioned metamophic processes on the natural remanent magnetization of the ophiolite was evaluated thru a susceptibility survey and a study of ferromagnetic (s.l ) minerals. These were identified by microscope observations under reflected and transmitted light. A very good agreement between magnetic susceptibility values and optical observations was found. Metamorphic processes have produced strong effects on ferromagnetic minerals. These metabasites are disctintly poor in titanomagnetites, except the metagabbros and dikes crosscutting gabbros, which show high susceptibilities due to magnetite from serpentinisation of olivines and uralitization of pyroxenes. Sheeted dikes and pillow lavas show low susceptibilities controlled by paramagnetic minerals with titanite as witness of a primary titanium-bearing mineral. Pure microcrystalline magnetite, main carrier of natural remanent magnetization, likely formed during the greenschist post-tectonic overprint. Sulfide mineralization in the Complex requires further studies. Finally, equilibria between Fe3+ in oxides and Fe3+ in

  9. Mitochondrial DNA diversity of feral pigs from Karukinka Natural Park, Tierra del Fuego Island, Chile.

    PubMed

    Aravena, P; Skewes, O; Gouin, N

    2015-04-28

    Control or eradication of exotic species is one of the greatest challenges facing biodiversity and ecosystem conservation. Domestic pigs (Sus scrofa domestica) were released and became feral in the southern region of Chilean Tierra del Fuego Island in the 1900s. Currently, they inhabit part of Karukinka Natural Park, an area of global conservation concern. To gain insight into the control of this invasive species, we analyzed genetic variation in the mitochondrial DNA control region to determine the origin and population subdivision of feral pigs in Tierra del Fuego. Sequences from a sample of 42 feral pigs, 10 domestic pigs from local farms, and references from other countries and commercial breeds revealed 2 highly differentiated populations, 1 in the western and the other in the eastern area of the park, each harboring a different haplotype, suggesting no connectivity between populations. Comparison of these haplotypes with reference sequences from other countries and commercial breeds indicated that feral pigs from Chilean Tierra del Fuego are of European origin, very likely from 2 separate introduction events. The haplotype found in the western feral population was also identified in domestic pigs from a farm. This raises concerns regarding the possible connectivity between stocks from local farms and the wild population. Based on these results, we recommend the development of strategies for controlling the population of this invasive species in Karukinka Natural Park.

  10. Coupled geohazards at Southern Andes (Copahue-Lanín volcanoes): Chile's GEO supersite proposal

    NASA Astrophysics Data System (ADS)

    Lara, Luis E.; Cordova, Loreto

    2017-04-01

    volcanism (the so-called Red Nacional de Vigilancia Volcánica at Sernageomin) and tectonics (Centro Sismólogico Nacional at Universidad de Chile) allow a good complement with space-borne data (e.g., we observed deformation by GPS and InSAR at Villarrica volcano related to the March 3, 2015 eruption) in order to promote basic and applied research for a successful national strategy of disaster risk reduction. In addition, at least 3 active national research grants focus in this area and a number of young scientists are working there. Thus, we propose the Copahue-Lanín (37.5-39.5°S) segment of the Southern Volcanic Zone as a Geohazards Supersite and look forward for an enhanced engagement of the scientific community in this area.

  11. The large late-glacial Ho eruption of the Hudson volcano, southern Chile

    NASA Astrophysics Data System (ADS)

    Weller, D.; Miranda, C. G.; Moreno, P. I.; Villa-Martínez, R.; Stern, C. R.

    2014-06-01

    Lakes formed in the Aysén region of southern Chile after the retreat of mountain glaciers, established by ~17,900 calendar years before present (cal years BP) or earlier, contain numerous late-glacial and Holocene tephra layers derived from >70 eruptions of the volcanoes in the region, including Hudson, the southernmost in the Andean Southern Volcanic Zone (SVZ). Sediment cores from seven of these lakes contain an unusually thick late-glacial age tephra layer, which based on its distribution and bulk trace-element composition was derived from a large explosive eruption of Hudson volcano between 17,300 and 17,440 cal years BP and is termed Ho. In 13 cores from six of these lakes, each located ~100 km generally northeast of Hudson, the Ho tephra layer ranges between 50 and 88 cm in thickness, and contains pumice grains up to 2 cm in maximum diameter. Comparison with three previously documented large explosive Holocene Hudson eruptions (H1 at 7,750 cal years BP, H2 at 3,920 cal years BP, and H3 in 1991 AD) suggests that Ho was larger, with an estimated tephra volume of >20 km3, the largest post-glacial eruption documented for any volcano in the southern Andes and most likely responsible for the formation of the Hudson caldera. In total, Hudson has erupted ≥45 km3 of pyroclastic material in the last ~17,500 years, making it the most productive volcano in the southern Andes in terms of the total volume erupted since the beginning of deglaciation in the region. Chemical stratification is not seen in the waterlain Ho tephra, but these deposits are bi-modal, consisting of a much greater proportion of dark glassy basaltic-trachyandesite dense fragments and pumice, with glasses which range between 55 and 59 wt.% SiO2, along with volumetrically less-significant lighter-colored trachydacite pumice, with glass of 66 wt.% SiO2. In contrast, H1 products are trachyandesitic in composition, H2 ones are more felsic than H1, being composed essentially of trachydacite, and although

  12. Saxitoxins and okadaic acid group: accumulation and distribution in invertebrate marine vectors from Southern Chile.

    PubMed

    García, Carlos; Pérez, Francisco; Contreras, Cristóbal; Figueroa, Diego; Barriga, Andrés; López-Rivera, Américo; Araneda, Oscar F; Contreras, Héctor R

    2015-01-01

    Harmful algae blooms (HABs) are the main source of marine toxins in the aquatic environment surrounding the austral fjords in Chile. Huichas Island (Aysén) has an history of HABs spanning more than 30 years, but there is limited investigation of the bioaccumulation of marine toxins in the bivalves and gastropods from the Region of Aysén. In this study, bivalves (Mytilus chilenses, Choromytilus chorus, Aulacomya ater, Gari solida, Tagelus dombeii and Venus antiqua) and carnivorous gastropods (Argobuccinum ranelliformes and Concholepas concholepas) were collected from 28 sites. Researchers analysed the accumulation of STX-group toxins using a LC with a derivatisation post column (LC-PCOX), while lipophilic toxins (OA-group, azapiracids, pectenotoxins and yessotoxins) were analysed using LC-MS/MS with electrospray ionisation (+/-) in visceral (hepatopancreas) and non-visceral tissues (mantle, adductor muscle, gills and foot). Levels of STX-group and OA-group toxins varied among individuals from the same site. Among all tissue samples, the highest concentrations of STX-group toxins were noted in the hepatopancreas in V. antiqua (95 ± 0.1 μg STX-eq 100 g(-1)), T. dombeii (148 ± 1.4 μg STX-eq 100 g(-1)) and G. solida (3232 ± 5.2 μg STX-eq 100 g(-1); p < 0.05); in the adductor muscle in M. chilensis (2495 ± 6.4 μg STX-eq 100 g(-1); p < 0.05) and in the foot in C. concholepas (81 ± 0.7 μg STX-eq 100 g(-1)) and T. dombeii (114 ± 1.2 μg STX-eq 100 g(-1)). The highest variability of toxins was detected in G. solida, where high levels of carbamate derivatives were identified (GTXs, neoSTX and STX). In addition to the detected hydrophilic toxins, OA-group toxins were detected (OA and DTX-1) with an average ratio of ≈1:1. The highest levels of OA-group toxins were in the foot of C. concholepas, with levels of 400.3 ± 3.6 μg OA eq kg(-1) (p < 0.05) and with a toxic profile composed of 90% OA. A wide range of OA-group toxins was detected in M. chilensis with a

  13. Coastal upwelling in Southern Coast of Sumbawa Island, Indonesia

    NASA Astrophysics Data System (ADS)

    Taufikurahman, Qamal; Hidayat, Rahmat

    2017-01-01

    Circulation and water mass characteristics in southern coast of Sumbawa Island is strongly influenced by monsoon which change each season. This research aims to (1) identify the Ekman transport and Ekman pumping variations and (2) analyse the SST and chlorophyll-a variability. During Juni-July-August (JJA) season, the highest value of Ekman transport (-0.72 m2 s-1) moves the water mass towards Indian Ocean while Ekman pumping (0.15x10-4 m2 s-1) rises the water mass to the surface (upwelling). Impact of coastal upwelling was identified by cooling SST and high chlorophyll-a. Coolest SST (26.58°C) associated with highest chlorophyll-a (0.6 mg m-3) were found in JJA season. Inter-annual variation of SST and chlorophyll-a concentrations during 2003-2015 is driven by Ekman transport and Ekman pumping. Coolest SST and highest chlorophyll-a were found in JJA season in 2006 with an average value of 25.98°C and 0.78 mg m-3, also in JJA season in 2008 with an average value of 26°C and 0.71 mg m-3. Thus the process of Ekman transport and Ekman pumping has an important role in lifting the cold water high nutriens from the deeper layer to surface. The high concentration of chlorophyll-a in water is the impact of appointment nutrient from the deeper layer by the coastal upwelling.

  14. Definition of sanitary boundaries to prevent ISAv spread between salmon farms in southern Chile based on numerical simulations of currents

    NASA Astrophysics Data System (ADS)

    Olivares, Gonzalo; Sepúlveda, H. H.; Yannicelli, B.

    2015-06-01

    The infectious Salmon Anemia virus (ISAv) is a pathogen that mainly affects the Atlantic Salmon (Salmo salar). It was detected in Norway in 1984 and in June 2007 appeared in Chile, producing a drop of more than 30% in the country's production level. It is expected that with certain regularity, outbreaks will continue to appear in Chile without the need of reintroducing the virus from foreign countries. We present a numerical study of the influence of winds and tides in the dispersion of lagrangian particles to simulate the transport of ISAv in the Aysen region, in southern Chile. This study combines the use of numerical models of the ocean and atmosphere, lagrangian tracking and biological aspects of ISAv infections. As in previous results, a wider dispersion of ISAv was observed during spring tides. Temporal changes in wind significantly modified the transport of viral particles from an infected center. Under similar forcing conditions, the areas of risk associated to culture sites separated by a few kilometers could be very different. Our main results remark the importance of the use of a detailed knowledge of hydrographic and atmospheric circulation in the definition of boundaries for sanitary management areas. We suggest that a methodology similar to the one presented in this study should be considered to define sanitary strategies to minimize the occurrence of native outbreaks of ISAv.

  15. The magmatic and eruptive response of arc volcanoes to deglaciation: insights from southern Chile

    NASA Astrophysics Data System (ADS)

    Rawson, Harriet; Mather, Tamsin A.; Pyle, David M.; Smith, Victoria C.; Fontijn, Karen; Lachowycz, Stefan; Naranjo, José A.; Watt, Sebastian F. L.

    2016-04-01

    Volcanism exerts a major influence on Earth's atmosphere and surface environments. Understanding feedbacks between climate and long-term changes in rates or styles of volcanism is important, but unresolved. For example, it has been proposed that a pulse of activity at once-glaciated volcanoes contributed to increasing atmospheric carbon dioxide accelerating early Holocene climate change. In plate-tectonic settings where magmatism is driven by decompression melting there is convincing evidence that activity is modulated by changes in ice- or water-loading across glacial/interglacial cycles. The response of subduction-related volcanoes, where the crust is typically thicker and mantle melting is dominated by flux melting, remains unclear. Since arc volcanoes account for 90% of subaerial eruptions, they are the most significant sources of volcanic gases and tephra directly to the atmosphere. Testing the response of arc volcanoes to deglaciation requires careful work to piece together eruption archives. Records of effusive eruptions from long-lived, arc stratovolcanoes are challenging to obtain and date; while deposits from the explosive eruptions, which dominate arc records, are prone to erosion and reworking. Our new high-resolution post-glacial (<18 ka) eruption record from a large stratovolcano in southern Chile (Mocho Choshuenco) provides new insight into the magmatic response following the removal of a regional ice load. We observe significant variations in eruptive flux, eruption size and magma composition across three distinct phases of post-glacial volcanic activity. Phase 1, shortly after deglaciation, was dominated by large explosive eruptions of dacite and rhyolite. During Phase 2 (7.3 - 2.9 ka) eruption rates and eruptive fluxes were lower, and activity was dominated by moderate-scale basaltic-andesite eruptions. For the past 2.4 kyr (Phase 3), eruptive fluxes have been elevated, and dominated by explosive eruptions of intermediate magmas. We propose that

  16. How linear is orographic precipitation? Insights from the Nahuelbuta mountains in Southern Chile

    NASA Astrophysics Data System (ADS)

    Garreaud, Rene; Falvey, Mark; Montecinos, Aldo

    2014-05-01

    The Nahuelbuta massif is located in the coast of southern Chile at about 38°S, with an elliptical shape (about 150 km long , 100 km wide) reaching 1300 m at its center. A network of 15 rain gauges was deployed during the austral winter of 2011 in the context of the Andean-Front-Experiment (AFEX) complemented by permanent stations in the surrounding lowlands. Precipitation in this region generally occurs during the passage of frontal systems with moderate to strong NW flow. The observations reveal the typical orographic modification of the seasonal accumulation: coastal upstream values of about 1000 mm/year increase to 2000 mm/year at the foothills and then to about 4000 mm/year atop of the mountain. Immediately downstream of the mountains the annual precipitation decreases to 500-700 mm/year. To determine the relative importance of linear and non-linear processes in producing the aforementioned orographic pattern, we conducted 2 simulations of the period May-September 2011: a full-physics continuous WRF run and Linear Theory (LT) model (Smith and Barstad 2004) run. The spatial pattern of the seasonal accumulation agrees very well among both models (r = 0.8). Comparisons with AFEX observations are more favorable for WRF: the LT model produces too much precipitation over the mountains and a too dry area downstream. We also analyzed each of the 27 precipitation events during 2011. The 30-min observations and WRF results reveal that the orographic modification is most notable during the prefrontal conditions when the mountain-to-lowland rainfall ratio as large as 10, and during the post-frontal conditions. Orographic effects are minor during the frontal period when the largest rainfall intensities occur. In this period the pattern is dominated by elongated bands of high rainfall leading to a high volatility of the rainfall distribution. The LT-model produce a rainfall pattern tightly tied to the topography that remains rather invariant during the precipitation events

  17. The magmatic and eruptive response of arc volcanoes to deglaciation: insights from southern Chile

    NASA Astrophysics Data System (ADS)

    Mather, T. A.; Rawson, H. L.; Smith, V.; Fontijn, K.; Lachowycz, S.; Pyle, D. M.; Naranjo, J. A.; Watt, S. F.

    2015-12-01

    In plate-tectonic settings where magmatism is driven by decompression melting there is convincing evidence that activity is modulated by changes in ice- or water-loading across glacial/interglacial cycles. In contrast, the response of subduction-related volcanoes, where the crust is typically thicker and mantle melting is dominated by flux melting, remains unclear. The large areas spanned by arcs, and the typical activity at subduction zone volcanoes present particular challenges when compiling regional eruption archives. Records of effusive eruptions from long-lived, arc stratovolcanoes are challenging to obtain, and date; while deposits from the explosive eruptions, which dominate arc records, are prone to erosion and reworking. Here we use a rare high-resolution post-glacial (<18 ka) eruption record from a large stratovolcano (Mocho-Choshuenco) in southern Chile to gain new insight into the magmatic response to removal of an ice load; variation in eruptive flux, eruption size and magma composition are observed and divided into three distinct phases based on style of activity and erupted composition. Phase 1, shortly after deglaciation, was dominated by large explosive eruptions of dacite and rhyolite. During Phase 2 (7.3 - 2.9 ka) eruption rates and eruptive fluxes were lower, and activity was dominated by moderate-scale basaltic-andesite eruptions. Since 2.4 ka (Phase 3) eruptive fluxes have been elevated, and dominated by explosive eruptions of more intermediate magmas. This time-varying behaviour reflects changes in crustal plumbing systems, and magma storage timescales. During glaciations, magmas stall and differentiate to form large, evolved crustal reservoirs. After the load is removed, much of this stored magma is erupted (Phase 1). Subsequently, less-differentiated melts infiltrate the shallow crust (Phase 2). Then, as storage timescales increase, volcanism returns to more evolved compositions (Phase 3). On short (<10 kyr) timescales these variations are

  18. The Early Toarcian Oceanic Anoxic Event: A Southern Hemisphere record from Chile

    NASA Astrophysics Data System (ADS)

    Fantasia, Alicia; Föllmi, Karl B.; Adatte, Thierry; Spangenberg, Jorge E.; Bernárdez, Enrique; Mattioli, Emanuela

    2016-04-01

    The Early Toarcian was marked by important environmental changes, marine oxygen deficiency and extensive organic-rich sediment deposition (T-OAE; ˜182 Ma, Early Jurassic). The T-OAE coincides with a marked negative carbon isotope excursion (CIE) recorded in marine carbonate, and marine and terrestrial organic carbon. This is commonly attributed to the massive release of isotopically light carbon to the atmospheric and oceanic reservoirs derived from the destabilization of methane hydrates from marine sediments and/or the emissions of thermogenic methane from the eruption of the Karoo-Ferrar LIP (e.g., Hesselbo et al., 2000; Kemp et al., 2005; Svensen et al., 2007; Mazzini et al., 2010). Moreover, in most documented marine sections, this episode is marked by a generalized crisis in carbonate production and marine invertebrate extinctions (e.g. Jenkyns, 1988; Röhl et al., 2005; Suan et al., 2001). Several studies of the T-OAE have been conducted on sediments in central and northwest Europe, but only few data are available from the Southern Hemisphere, leading to large uncertainty concerning the exact expression of this event in this part of the world. The aims of this study are to characterize the sediments deposited during the Andean equivalents of the tenuicostatum and falciferum European Zones and establish in which way the T-OAE affected this region. In the Early Jurassic, the Andean basin was in a back-arc setting with marine corridors connected to Panthalassa. In this study, we have generated new high-resolution sedimentological, geochemical and mineralogical data from the sections of El Peñon and Quebrada Asiento, located in Chile in the northeastern area of the city of Copiapó, Atacama region. The biostratigraphy of these sections has been studied by von Hillebrandt and Schidt-Effing (1981) and complemented here by a biostratigraphy based on calcareous nannofossils. The sections consist of a succession of marl, limestone and siltstone of Pliensbachian and

  19. Wood burning pollution in southern Chile: PM2.5 source apportionment using CMB and molecular markers.

    PubMed

    Villalobos, Ana M; Barraza, Francisco; Jorquera, Héctor; Schauer, James J

    2017-06-01

    Temuco is a mid-size city representative of severe wood smoke pollution in southern Chile; i.e., ambient 24-h PM2.5 concentrations have exceeded 150 μg/m(3) in the winter season and the top concentration reached 372 μg/m(3) in 2010. Annual mean concentrations have decreased but are still above 30 μg/m(3). For the very first time, a molecular marker source apportionment of ambient organic carbon (OC) and PM2.5 was conducted in Temuco. Primary resolved sources for PM2.5 were wood smoke (37.5%), coal combustion (4.4%), diesel vehicles (3.3%), dust (2.2%) and vegetative detritus (0.7%). Secondary inorganic PM2.5 (sulfates, nitrates and ammonium) contributed 4.8% and unresolved organic aerosols (generated from volatile emissions from incomplete wood combustion), including secondary organic aerosols, contributed 47.1%. Adding the contributions of unresolved organic aerosols to those from primary wood smoke implies that wood burning is responsible for 84.6% of the ambient PM2.5 in Temuco. This predominance of wood smoke is ultimately due to widespread poverty and a lack of efficient household heating methods. The government has been implementing emission abatement policies but achieving compliance with ambient air quality standards for PM2.5 in southern Chile remains a challenge. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Earthquake relocation near the Leech River Fault, southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Li, G.; Liu, Y.; Regalla, C.

    2015-12-01

    The Leech River Fault (LRF), a northeast dipping thrust, extends across the southern tip of Vancouver Island in Southwest British Columbia, where local tectonic regime is dominated by the subduction of the Juan de Fuca plate beneath the North American plate at the present rate of 40-50 mm/year. British Columbia geologic map (Geoscience Map 2009-1A) shows that this area also consists of many crosscutting minor faults in addition to the San Juan Fault north of the LRF. To investigate the seismic evidence of the subsurface structures of these minor faults and of possible hidden active structures in this area, precise earthquake locations are required. In this study, we relocate 941 earthquakes reported by Canadian National Seismograph Network (CNSN) catalog from 2000 to 2015 within a 100km x 55km study area surrounding the LRF. We use HypoDD [Waldhauser, F., 2001] double-difference relocation method by combining P/S phase arrivals provided by the CNSN at 169 stations and waveform data with correlation coefficient values greater than 0.7 at 50 common stations and event separation less than 10km. A total of 900 out of the 931 events satisfy the above relocation criteria. Velocity model used is a 1-D model extracted from the Ramachandran et al. (2005) model. Average relative location errors estimated by the bootstrap method are 546.5m (horizontal) and 1128.6m (in depth). Absolute errors reported by SVD method for individual clusters are ~100m in both dimensions. We select 5 clusters visually according to their epicenters (see figure). Cluster 1 is parallel to the LRF and a thrust FID #60. Clusters 2 and 3 are bounded by two faults: FID #75, a northeast dipping thrust marking the southwestern boundary of the Wrangellia terrane, and FID #2 marking the northern boundary. Clusters 4 and 5, to the northeast and northwest of Victoria respectively, however, do not represent the surface traces of any mapped faults. The depth profile of Cluster 5 depicts a hidden northeast

  1. Carbon stocks and greenhouse gas balance of an old-growth forest and an anthropogenic peatland in southern Chile

    NASA Astrophysics Data System (ADS)

    Perez-Quezada, J. F.; Brito, C. E.; Valdés, A.; Urrutia, P.

    2016-12-01

    Few studies have reported the effects of deforestation on carbon stocks and greenhouse gas balance in the temperate forests of the southern hemisphere. In some areas of southern Chile, after clear-cut or forest fires occurs a proliferation of Sphagnum moss, generating an anthropogenic type of peatland. We measured the effects of this change on the carbon stocks and the greenhouse gas balance, starting in 2013. Carbon stocks were measured in >30 plots on each site; ecosystem CO2 fluxes were measured continuously using eddy covariance stations; CH4 and N2O fluxes were measured monthly using closed chambers and cavity ring-down spectroscopy technology. Total ecosystem carbon stock was 1,523 Mg ha-1 in the forest and 130 Mg ha-1 in the peatland, representing a 91% difference. Both land use types were found to act as sinks of CO2 (NEE=-1094.2 and -31.9 g CO2 m-2 year-¹ for the forest and peatland, respectively); CH4 was mainly captured in the forest and peatland soils, generating balances of -0.70 and -0.12 g CH₄ m-2 year-¹. N2O fluxes were extremely low, so were considered as null. These results indicate that the greenhouse gas balance moved from -1134.6 to -38.8 g CO2-eq m-2 year-1 when land use changed from forest to anthropogenic peatland. These results provide evidence of the importance of preserving old-growth forests in southern Chile.

  2. Recent (210)Pb, (137)Cs and (241)Am accumulation in an ombrotrophic peatland from Amsterdam Island (Southern Indian Ocean).

    PubMed

    Li, Chuxian; Le Roux, Gaël; Sonke, Jeroen; van Beek, Pieter; Souhaut, Marc; Van der Putten, Nathalie; De Vleeschouwer, François

    2017-09-01

    Over the past 50 years, (210)Pb, (137)Cs and (241)Am have been abundantly used in reconstructing recent sediment and peat chronologies. The study of global aerosol-climate interaction is also partially depending on our understanding of (222)Rn-(210)Pb cycling, as radionuclides are useful aerosol tracers. However, in comparison with the Northern Hemisphere, few data are available for these radionuclides in the Southern Hemisphere, especially in the South Indian Ocean. A peat core was collected in an ombrotrophic peatland from the remote Amsterdam Island (AMS) and was analyzed for (210)Pb, (137)Cs and (241)Am radionuclides using an underground ultra-low background gamma spectrometer. The (210)Pb Constant Rate of Supply (CRS) model of peat accumulations is validated by peaks of artificial radionuclides ((137)Cs and (241)Am) that are related to nuclear weapon tests. We compared the AMS (210)Pb data with an updated (210)Pb deposition database. The (210)Pb flux of 98 ± 6 Bq·m(-2)·y(-1) derived from the AMS core agrees with data from Madagascar and South Africa. The elevated flux observed at such a remote location may result from the enhanced (222)Rn activity and frequent rainfall in AMS. This enhanced (222)Rn activity itself may be explained by continental air masses passing over southern Africa and/or Madagascar. The (210)Pb flux at AMS is higher than those derived from cores collected in coastal areas in Argentina and Chile, which are areas dominated by marine westerly winds with low (222)Rn activities. We report a (137)Cs inventory at AMS of 144 ± 13 Bq·m(-2) (corrected to 1969). Our data thus contribute to the under-represented data coverage in the mid-latitudes of the Southern Hemisphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Determining rates of Quaternary uplift across the Santa Rosa Island Fault, Channel Islands National Park, Southern California

    NASA Astrophysics Data System (ADS)

    Cyr, A.; Schmidt, K. M.; Minor, S. A.; Bedford, D.

    2014-12-01

    The northern Channel Islands, southern California, form the southern margin of the western Transverse Ranges. They constitute a roughly east-west trending emergent ridge uplifted as a result of south-vergent shortening and left-lateral slip, mostly on west-striking, north-dipping faults. Late Quaternary uplift of these islands is recorded by two prominent wave-cut platforms, which occur at elevations of ~5-7 and ~6-24 meters above sea level, have been attributed by previous workers to Marine Isotope Stages (MIS) 5a (~80ka) and 5e (~120 ka), and indicate low and somewhat spatially variable, uplift rates of 0.1-0.2 mm/yr. We have documented evidence of older, higher marine features, such as shoreline angles, beveled surfaces buried by aeolian sand, and pholad borings, in the interior of Santa Rosa Island. Our simple steady uplift models indicate that the highest of these paleo shore line markers, which occur at ~275 m, could be anywhere from ~1.2 Ma to ~2.7 Ma. However, despite their importance for understanding longer term uplift rates associated with the Santa Rosa Island fault and/or other faults, their ages remain unknown. As part of a cooperative effort with the National Park Service to complete a new Quaternary geologic map of the northern Channel Islands, we collected samples of quartz-bearing rock and sediment at seven locations on Santa Rosa Island, representative of 6 paleo shorelines spanning elevations between ~65 and ~275 meters above sea level, from both sides of the Santa Rosa Island fault. Rock samples were collected from moderately indurated fossiliferous marine sands that either contain pholad-bored clasts or overlie a beveled bedrock surface in order to determine 10Be exposure ages. Sediments were collected from where they directly overlie shoreline angles for determination of 10Be-26Al burial ages. Ages of these paleo sea level markers will enable us to test previous assumptions of steady island uplift, as well as allow us to test hypotheses

  4. Osmium isotopic evidence for ancient subcontinental lithospheric mantle beneath the kerguelen islands, southern indian ocean

    PubMed

    Hassler; Shimizu

    1998-04-17

    Upper mantle xenoliths found in ocean island basalts are an important window through which the oceanic mantle lithosphere may be viewed directly. Osmium isotopic data on peridotite xenoliths from the Kerguelen Islands, an archipelago that is located on the northern Kerguelen Plateau in the southern Indian Ocean, demonstrate that pieces of mantle of diverse provenance are present beneath the Islands. In particular, peridotites with unradiogenic osmium and ancient rhenium-depletion ages (to 1.36 x 10(9) years old) may be pieces of the Gondwanaland subcontinental lithosphere that were incorporated into the Indian Ocean lithosphere as a result of the rifting process.

  5. Stilbene levels in grape cane of different cultivars in southern Chile: determination by HPLC-DAD-MS/MS method.

    PubMed

    Vergara, Carola; von Baer, Dietrich; Mardones, Claudia; Wilkens, Andrea; Wernekinck, Katerina; Damm, Anika; Macke, Sebastian; Gorena, Tamara; Winterhalter, Peter

    2012-02-01

    Health benefits of trans-resveratrol and other stilbenes in grapes, must, and wine have been pointed out by numerous authors. Less attention has been paid to the presence of stilbene derivatives in viticultural residues, such as grape canes. The present work reports the first results of a systematic study of stilbene levels in different grape varieties and cultivation areas in Chile, to evaluate their potential as an alternative source of bioactive stilbenes. In all cane samples, the predominant stilbene is trans-resveratrol, followed by ε-viniferin and piceatannol. In canes of Pinot noir up to 5590 ± 172 mg kg(-1) of trans-resveratrol and up to 6915 ± 175 mg kg(-1) of total stilbenes were detected. The observed concentrations of stilbenes in canes of Pinot noir from southern Chile until now are higher than those reported previously for this red variety. However, the highest concentration of total stilbenes observed in the analyzed samples was in the canes of white variety Gewürztraminer with 7857 ± 498 mg kg(-1). Preliminary results indicate that these levels can evolve if canes are left for some months on the vineyard after pruning, observing an increase during the first 2 months and a decrease after this period.

  6. Increase in sunburns and photosensitivity disorders at the edge of the Antarctic ozone hole, southern Chile, 1986-2000.

    PubMed

    Abarca, Jaime F; Casiccia, Claudio C; Zamorano, Felix D

    2002-02-01

    Over the past 15 years Punta Arenas, Chile, a medium-sized city located on the extreme southern tip of South America, has repeatedly been exposed to acute, sudden episodes of highly increased levels of ultraviolet B (UVB) 280-320 nm radiation because of the passage of the spring Antarctic "Ozone Hole" overhead, or nearby. Our purpose was to observe the relationship between episodes of ozone depletion, increased UVB radiation, and sunburns and photosensitivity disorders in Punta Arenas, Chile, during spring. Incidence of photosensitivity disorders and sunburns was registered by dermatologists during each of the past 15 springs. Local data of sudden, severe ozone depletions (<250 Dobson units) and the corresponding increase of UVB radiation were reviewed. Patients with sunburn increased significantly during the austral spring of 1999 (P <.01). This was especially noticeable (29/31 cases) on weekends with ozone depletion, and increased UVB radiation (P <.01) occurred on the Sundays Oct 31, Nov 21, and Dec 5, 1999. The incidence of photosensitivity disorders, although statistically not significant, increased 51% over the past 7 years. An acute impact on human health (sunburn) occurred because of abrupt ozone depletion and the accompanying increase in UVB during the mid and late austral spring of 1999. Most sunburns (93.5%) occurred on weekends. Ozone levels as well as seasonal and recreational factors played a mayor role in the increase in sunburns. The increase in radiation at 300 nm, the most carcinogenic wavelength, on days under the Antarctic ozone hole is a matter of special concern.

  7. Calbuco volcano (Southern Chile) Eruption 22-23 April 2015: pyroclastic fall deposits and preliminary petrological study

    NASA Astrophysics Data System (ADS)

    Morgavi, Daniele; Romero, Jorge; Arzilli, Fabio; Daga, Romina; Caselli, Alberto; Reckziegel, Florencia; Viramonte, Jose; Polacci, Margherita; Burton, Mike; Perugini, Diego

    2016-04-01

    After 54 years since its last major eruption in 1961, Calbuco volcano (Ensenada, Southern Chile) reawakened with few hours of warning on 22 April 2015 at 18:05 local time. The main explosive eruption consisted of two eruption pulses (lasting ~1.5 and ~6 hours each one) on 22 and 23 April, producing stratospheric (>15 km height) eruption columns. The tephra fall affected mainly the area northeast of the volcano and the finest ash was deposited over Southern Chile and Patagonia Argentina. We studied the tephra fall deposits of both pulses in terms of stratigraphy, distribution, volume, emplacement dynamics and eruption source parameters. Here, we show field observations made from 5 to 470 km downwind and we distinguish five layers (Layers A, B, B1, C and D) representing different stages of the eruption evolution. The total calculated bulk tephra fall deposit volume is 0.27±0.007 km3 (0.11-0.13 km3 dense rock equivalent). The 38% of it was erupted during the first phase and 62% during the second pulse. This eruption was a magnitude 4.45 event (VEI 4 eruption) of Subplinian type. The erupted materials correspond to a porphyritic basaltic-andesite (54.40-57.2 wt. of % SiO2). It produced two types of pumice clasts: high density pumice (HDP), poorly vesiculated and crystal-rich (up to 40 % crystals by volume), and lower density pumice (LDP) characterized by a slightly lower crystallinity and higher vesicle fraction. The textures include phenocrysts in a glassy groundmass with a minor presence of microlites. The mineralogical assemblage of pumices consists of plagioclase (Pl), orthopyroxene (Opx), clinopyroxene (Cpx), Ti-magnetite, and sanidine (Sa) as accessory mineral.

  8. Conceptual hydrogeological model of volcanic Easter Island (Chile) after chemical and isotopic surveys

    NASA Astrophysics Data System (ADS)

    Herrera, Christian; Custodio, Emilio

    2008-11-01

    Most human activities and hydrogeological information on small young volcanic islands are near the coastal area. There are almost no hydrological data from inland areas, where permanent springs and/or boreholes may be rare or nonexistent. A major concern is the excessive salinity of near-the-coast wells. Obtaining a conceptual hydrogeological model is crucial for groundwater resources development and management. Surveys of water seepages and rain for chemical and environmental isotope contents may provide information on the whole island groundwater flow conditions, in spite of remaining geological and hydrogeological uncertainties. New data from Easter Island (Isla de Pascua), in the Pacific Ocean, are considered. Whether Easter Island has a central low permeability volcanic “core” sustaining an elevated water table remains unknown. Average recharge is estimated at 300-400 mm/year, with a low salinity of 15-50 mg/L Cl. There is an apron of highly permeable volcanics that extends to the coast. The salinity of near-the-coast wells, >1,000 mg/L Cl, is marine in origin. This is the result of a thick mixing zone of island groundwater and encroached seawater, locally enhanced by upconings below pumping wells. This conceptual model explains what is observed, in the absence of inland boreholes and springs.

  9. [Copepode parasites of fish from the Kerkennah Islands (Southern Tunisia)].

    PubMed

    Essafi, K; Cabral, P; Raibaut, A

    1984-12-01

    Out of 29 species of fish from the Kerkennah Islands examined, 30 species of parasitic copepoda were collected which belong to seven families and nine different genera. Among them three new species have been found and ten were reported for the first time in Tunisia.

  10. [Diversity patterns in intertidal communities of three southern islands of Changshan archipelago].

    PubMed

    Zhuang, Shuhong; Chen, Lixue; Wang, Zunqing

    2003-05-01

    The diversity pattern of intertidal communities in 3 southern islands of Changshan archipelago were studied. The results showed that the community appearance and structure in rocky intertidal zones of 3 islands were regimented by dominant species Chthamalus challengeri, Ostrea spp., macro-algae and Littorina brevicula, while in gravel intertidal zones of Southern Changshan and Daheishan regimented by Chthamalus challengeri, Littorina brevicula, Ostrea spp., and in Northern Changshan, by Chthamalus challengeri, macro-algae and Gaetice depressus. There existed no obvious difference in community structures of rocky intertidal zones among 3 islands, which was demonstrated by the similarity in first 5 dominant species and their dominance ranks in the community. However, a significant difference was achieved in gravel intertidal communities, in which, the dominant species in the community at Northern Changshan differed greatly from that of others. The community diversity in R, J, D(B), D(IV), H(B), and H(IV), in rocky intertidal communities among 3 islands showed a great coincidence, Northern Changshan > Southern Changshan > Daheishan, however, little coincident results were found among gravel intertidal communities. It was found that there existed a higher community diversity in gravel intertidal communities at Daheishan and Southern Changshan than at Northern Changshan where existed the highest species evenness. The community diversity was generally higher in gravel intertidal communities than in rocky intertidal ones. The variation in community compositions, structures and diversities were resulted mainly from topographical heterogeneities, substratum heterogeneities, hydrodynamics, water eutrophication and human disturbance in intertidal zones.

  11. The southern Whidbey Island fault: An active structure in the Puget Lowland, Washington

    USGS Publications Warehouse

    Johnson, S.Y.; Potter, C.J.; Armentrout, J.M.; Miller, J.J.; Finn, C.; Weaver, C.S.

    1996-01-01

    Information from seismic-reflection profiles, outcrops, boreholes, and potential field surveys is used to interpret the structure and history of the southern Whidbey Island fault in the Puget Lowland of western Washington. This northwest-trending fault comprises a broad (as wide as 6-11 km), steep, northeast-dipping zone that includes several splays with inferred strike-slip, reverse, and thrust displacement. Transpressional deformation along the southern Whidbey Island fault is indicated by alongstrike variations in structural style and geometry, positive flower structure, local unconformities, out-of-plane displacements, and juxtaposition of correlative sedimentary units with different histories. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. The Cascade block to the northeast is floored by diverse assemblages of pre-Tertiary rocks; the Coast Range block to the southwest is floored by lower Eocene marine basaltic rocks of the Crescent Formation. The fault probably originated during the early Eocene as a dextral strike-slip fault along the eastern side of a continental-margin rift. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. Evidence for Quaternary movement on the southern Whidbey Island fault includes (1) offset and disrupted upper Quaternary strata imaged on seismic-reflection profiles; (2) borehole data that suggests as much as 420 m of structural relief on the Tertiary-Quaternary boundary in the fault zone; (3) several meters of displacement along exposed faults in upper Quaternary sediments; (4) late Quaternary folds with limb dips of as much as ???9??; (5) large-scale liquefaction features in upper Quaternary sediments within the fault zone; and (6) minor historical seismicity. The southern Whidbey

  12. The Southern Kurile Islands: Shrouded in Eternal Fog

    DTIC Science & Technology

    2012-03-22

    unrealistic due to being overly complicated and prone to be very time consuming. Markku Heiskanen draws insights from the Åland resolution for autonomy...2012). 143 An assessment in 2007 was that the islands had lost their former military significance. See Markku Heiskanen , “Solving the Territorial...Kurillian Knot, ed. Kimie Hara and Geoffrey Jukes (New York, NY: Routledge, 2009), 118. 240 Heiskanen , “Solving the Territorial Dispute Between Japan and

  13. Thermal State of the Seismogenic Plate Boundary in Southern Chile, 36 -- 46 °S

    NASA Astrophysics Data System (ADS)

    Heesemann, M.; Grevemeyer, I.; Villinger, H. W.; Contreras-Reyes, E.; Scherwath, M.; Völker, D.

    2006-12-01

    According to current models of great subduction earthquakes, the area of the ruptured zone, and therefore the magnitude of the event, is controlled by the thermal structure of the plate boundary; updip and downdip limits of the seismogenic zone coincide with temperatures of 100 - 150 °C and 350 - 450°C, respectively. From this point of view, the 1960 Chile earthquake (M_W=9.5), which is the largest earthquake ever been recorded, was not only an outstanding event in respect to its magnitude. Also, the thermal structure of the young oceanic crust subducted along the ~1000 km long rupture area north of the Chile Triple Junction is remarkable, since considerable variability is caused by ocean floor ages ranging from ~0 - 30 Ma. Being part of the multi-disciplinary and multi-institutional project TIPTEQ (from The Incoming Plate to mega- Thrust EarthQuake processes), we present the correlation of lateral variations in the thermal structure of the 1960 Chile earthquake rupture area with seismic activity. Finite element method (FEM) models based on the Comsol Multiphysics code are used to estimate the thermal state of the plate boundary. To constrain the FEM models, scarce existing heat flux data were supplemented by 63 successful deployments of violin bow type heat flux probes during RV Sonne cruise 181-1b from December 2004 through January 2005. On the continental slope, additional constrains on the heat flux were derived from abundant bottom simulating reflectors (BSRs) found in seismic reflection data. Geometry information and seismic activity were obtained from TIPTEQ and Subduction Processes Off-shore Chile (SPOC) local seismological networks along the rupture area. From heat flux measurements on the incoming plate, which are generally lower than expected from conductive cooling models, we inferred advective cooling by circulating fluids in the upper oceanic crust and effects of rapid sedimentation close to the trench. These processes had to be taken into account

  14. Cordon Caulle: an active volcanic-geothermal extensional system of Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Sepulveda, F.

    2013-05-01

    Cordon Caulle (CC; 40.5° S) is an active volcanic-geothermal system of the Southern Volcanic Zone (SVZ; 37°-44°S). Morphologically, the CC system is a 6 km x 13 km volcanic plateau bordered by NW-trending structures, limited by Puyehue Volcano to the SE and by Caldera Nevada Caldera to the NW. While the SVZ is dominantly basaltic, CC is unique in that it has produced a wide compositional spectrum from basalt to rhyolite. The most recent volcanic activity of Puyehue-CC (last 70 ky) is dominantly silicic, including two historic fissure eruptions (1921-1922; 1960) and a recent central eruption from Puyehue Volcano (2011). Abnormally silicic volcanism was formerly attributed to a localized compression and long-term magma residence and differentiation, resulting from the NW orientation of underlying CC structures with respect to a NE-oriented σ1 (linked to regional strike-slip stress state). However, later studies, including examination of morpho-tectonic features; detailed structural analysis of the 1960 eruption (triggered by Mw 9.5 1960 Chilean Earthquake); InSAR deformation and gravity surveys, point to both historic and long-term extension at CC with σhmax oriented NNW to NW. The pre-2011 (i.e. Puyehue Volcano eruption) geothermal features of CC included boiling hot springs and geysers (Caldera Nevada) and fumaroles (CC and Puyehue Volcano). Both water and gas chemistry surveys were undertaken to assess the source fluid composition and equilibrium temperature. The combination of water and gas geothermometers led to a conceptual model of a stratified geothermal reservoir, with shallow, low-chloride, steam-heated aquifers equilibrated at temperatures between 150°-180°C, overlying a deeper, possibly dominated reservoir with temperatures in excess of 280°C. Gas chemistry also produced the highest He ratios of the SVZ, in agreement with a relatively pure, undiluted magmatic signature and heat source fueling the geothermal system. Other indicators such as N2/Ar

  15. Changing fire regimes in the temperate rainforest region of southern Chile over the last 16,000 yr

    NASA Astrophysics Data System (ADS)

    Abarzúa, Ana M.; Moreno, Patricio I.

    2008-01-01

    A high-resolution macroscopic charcoal record from Lago Melli (42°46'S, 73°33'W) documents the occurrence of forest fires in the lowlands of Isla Grande de Chiloé, southern Chile, over the last 16,000 yr. Our data suggest that fire activity in this region was largely modulated by the position/intensity of the southern westerlies at multi-millennial time scales. Fire activity was infrequent or absent between 16,000-11,000 and 8500-7000 cal yr BP and was maximal between ˜ 11,000-8500 and 3000-0 cal yr BP. A mosaic of Valdivian/North Patagonian rainforest species started at ˜ 6000 cal yr BP, along with a moderate increase in fire activity which intensified subsequently at 3000 cal yr BP. The modern transition between these forest communities and the occurrence of fires are largely controlled by summer moisture stress and variability, suggesting the onset of high-frequency variability in summer precipitation regimes starting at ˜ 5500 cal yr BP. Because negative anomalies in summer precipitation in this region are teleconnected with modern El Niño events, we propose that the onset of El Niño-like variability at ˜ 5700-6200 cal yr BP led to a reshuffling of rainforest communities in the lowlands of Isla Grande de Chiloé and an increase in fire activity.

  16. Climate change impact on hydroclimate regimes and extremes over Andean basins in the central-southern Chile

    NASA Astrophysics Data System (ADS)

    Bozkurt, Deniz; Rojas, Maisa; Valdivieso, Jonás; Falvey, Mark

    2015-04-01

    We have assessed the impact of projected increases in temperature and decreased precipitation on variability and potential changes in hydroclimate regimes and extremes over Andean basins in the central-southern Chile (~30-40S). The altitude of the southern Andes in the study area has an average altitude of 5000 m in the north that decreases to 3000 m at the southern edge. Climatically the region has a Mediterranean-like climate with mainly winter precipitation that gradually increases southwards, from around 300 mm/yr to 1000 mm/yr. The region is home to most of the population in Chile (~10 mil. inhabitants), it has fertile and productive agriculture land, as well as hydro-electrical power plants. During the 20th Century the region has experienced a decreasing precipitation trend imbedded in important interannual and decadal scale variability. We have used gridded observed daily precipitation and temperatures to drive and validate the VIC macro-scale model over the region of interest at 0.25 x 0.25 degree resolution. Historical (1960-2005) and projected (RCP8.5, 2006-2099) daily precipitation and temperatures from 28 CMIP5 models are adjusted via a transfer function based on the gridded observed daily precipitation and temperature data. Adjusted time series are then used to drive the VIC model in order to present climate change projections. The hydrological model simulations foresee that drying is robust in the models and total annual runoff will decrease in the future (40-45% by the end of the century). Center timing of runoff tends to shift to earlier days (3-5 weeks by the end of the century). In some areas over the Andes winter runoff is projected to increase due to upward movement of zero isotherm. Moreover, reductions in the amount of snowpack and accelerated snowmelt lead to more pronounced increase in winter evapotranspiration over the same areas. The simulated 12-months Standardized Runoff Index (SRI) clearly shows severe persistent hydrological droughts

  17. Differential invasion success of salmonids in southern Chile: patterns and hypotheses

    USGS Publications Warehouse

    Arismendi, Ivan; Penaluna, Brooke E.; Dunham, Jason B.; García de Leaniz, Carlos; Soto, Doris; Fleming, Ian A.; Gomez-Uchidam, Daniel; Gajardo, Gonzalo; Vargas, Pamela V.; León-Muñoz, Jorge

    2014-01-01

    Biological invasions create complex ecological and societal issues worldwide. Most of the knowledge about invasions comes only from successful invaders, but less is known about which processes determine the differential success of invasions. In this review, we develop a framework to identify the main dimensions driving the success and failure of invaders, including human influences, characteristics of the invader, and biotic interactions. We apply this framework by contrasting hypotheses and available evidence to explain variability in invasion success for 12 salmonids introduced to Chile. The success of Oncorhynchus mykiss and Salmo trutta seems to be influenced by a context-specific combination of their phenotypic plasticity, low ecosystem resistance, and propagule pressure. These well-established invaders may limit the success of subsequently introduced salmonids, with the possible exception of O. tshawytscha, which has a short freshwater residency and limited spatial overlap with trout. Although propagule pressure is high for O. kisutch and S. salar due to their intensive use in aquaculture, their lack of success in Chile may be explained by environmental resistance, including earlier spawning times than in their native ranges, and interactions with previously established and resident Rainbow Trout. Other salmonids have also failed to establish, and they exhibit a suite of ecological traits, environmental resistance, and limited propagule pressure that are variably associated with their lack of success. Collectively, understanding how the various drivers of invasion success interact may explain the differential success of invaders and provide key guidance for managing both positive and negative outcomes associated with their presence.

  18. Connectivity, small islands and large distances: the Cellana strigilis limpet complex in the Southern Ocean.

    PubMed

    Reisser, Céline M O; Wood, Ann R; Bell, James J; Gardner, Jonathan P A

    2011-08-01

    The Southern Ocean contains some of the most isolated islands on Earth, and fundamental questions remain regarding their colonization and the connectivity of their coastal biotas. Here, we conduct a genetic investigation into the Cellana strigilis (limpet) complex that was originally classified based on morphological characters into six subspecies, five of which are endemic to the New Zealand (NZ) subantarctic and Chatham islands (44-52°S). Previous genetic analyses of C. strigilis from six of the seven island groups revealed two lineages with little or no within-lineage variation. We analysed C. strigilis samples from all seven island groups using two mitochondrial (COI and 16S), one nuclear (ATPase β) and 58 loci from four randomly amplified polymorphic DNA markers (RAPDs) and confirmed the existence of two distinct lineages. The pronounced genetic structuring within each lineage and the presence of private haplotypes in individual islands are the result of little genetic connectivity and therefore very high self-recruitment. This study supports the significance of the subantarctic islands as refugia during the last glacial maximum and adds to the knowledge of contemporary population connectivity among coastal populations of remote islands in large oceans and the distance barrier to gene flow that exists in the sea (despite its continuous medium) for most taxa.

  19. Holocene submergence of southern Long Island, New York

    NASA Technical Reports Server (NTRS)

    Rampino, M. R.

    1979-01-01

    Samples of basal peat from south-central Long Island have been dated by the radiocarbon method, and a local curve of submergence has been obtained for the past 8,000 yr. The submergence curve indicates that from 7,000 and 3,000 yr BP the Long Island coast was being submerged at a rate of about 25 cm per 100 yr, a rate which slowed markedly to about 10 cm per 100 yr during the past 3,000 yr. Sea-level data for before 7,000 yr show considerable scatter. Samples from the fringing and mid-bay marsh areas of the Great South Bay taken at depths of -1.1 and -0.3 m MSL gave radiocarbon ages of about 1,015 and 300 yr, respectively. The inception of these marshes is estimated to have occurred at about 2,000 yr BP. It seems likely that the change from open lagoon to saltmarsh was initiated in the Great South Bay by a decrease in the rate of submergence at about 3,000 yr BP, which allowed sedimentation to build the floor of the lagoon to a level suitable for colonization by marsh grasses.

  20. Monitoring of a Southern Giant Petrel Macronectes giganteus population on the Frazier Islands, Wilkes Land, Antarctica

    USGS Publications Warehouse

    Creuwels, J.C.S.; Stark, J.S.; Woehler, Eric J.; Van Franeker, J. A.; Ribic, C.A.

    2005-01-01

    Since 1956, Southern Giant Petrels on the Frazier Islands, East Antarctica, have been counted with different census techniques, sometimes varying within seasons and among islands, which hindered analysis of the data. Protective measures for the islands from 1986 onwards have increased the need for reliable long-term census data, but reduced the ways to collect these data. Published and unpublished data were re-examined, and population trends were reconstructed based on two relatively standardised techniques: the number of active chicks (AC) and the number of apparently occupied nests (AON) around hatching. AC-values from Nelly Island from 1959 to 1998 indicate substantial periodic fluctuations, but no consistent long-term change. Since the late 1970s, AC-values on the other two islands and AON-values suggest that the breeding population may have grown by 35%. This recent growth, however, is within the extent of periodic fluctuations observed in Southern Giant Petrel population that is stable over the long term. ?? Springer-Verlag 2004.

  1. Lactase persistence and dairy intake in Mapuche and Mestizo populations from southern Chile.

    PubMed

    Fernández, Catalina I; Flores, Sergio V

    2014-11-01

    Lactase persistence (LP) occurs at a very low frequency in indigenous populations from Latin America, offering an opportunity to understand the relationship between this genetic trait and patterns of dairy consumption. Here, the frequency of LP is analyzed from Mapuche and -an adjacent- mestizo population inhabiting the Araucanía region. In addition to genotyping for LP, participants were surveyed in relation to general perception and consumption habits of dairy products. Low LP frequency (10%) and very low dairy intake was found among the Mapuche population as compared with Mestizo populations inhabiting Chile. The survey reported that the main reasons for avoidance of dairy were the gastrointestinal symptoms after dairy intake and cultural dietary habits. The interaction between low LP genotype frequency, low dairy intake, and sociocultural determinants is here discussed in the light of their potential health outcomes. © 2014 Wiley Periodicals, Inc.

  2. Putting the market in its place: food security in three Mapuche communities in southern Chile.

    PubMed

    Clark, Timothy David

    2011-01-01

    This article analyzes the impact of state policies since the 1970s on household food security in several Mapuche communities in the Araucanía region of Chile (Region IX). The author highlights key transformations in the national economy and food system and endeavors to link those to local phenomena, in particular the absorption of the local livelihood strategies and food systems into capitalist markets and the high incidences of food insecurity. The article concludes that a reconceptualization of macroeconomic and indigenous policies are required to rebuild the material and social foundations of rural Mapuche communities that provide the bases from which their inhabitants can reconstruct a mutually beneficial relationship with the broader Chilean society and avert the continued acceleration of tension and violence.

  3. Orogenesis at the southern tip of the Americas: the structural evolution of the Cordillera Darwin metamorphic complex, southernmost Chile

    NASA Astrophysics Data System (ADS)

    Cunningham, W. Dickson

    1995-04-01

    New, detailed lithologic and structural data are presented from three separately mapped areas along the southern boundary of the Cordillera Darwin metamorphic complex of southernmost Chile. Cordillera Darwin is a unique uplift because it exposes the highest grade rocks in the Andes south of Peru and averages 1 km higher in elevation than adjacent areas. The structural data indicate that Cordillera Darwin experienced mid-Late Cretaceous trans-pressional deformation with a partitioned strike-slip component localized along the Beagle Channel that forms the southern boundary to the range. Foliation, lineation and fold axis trends indicate NE-SW-directed contraction and NW-SE strike-slip shearing (present directions) during progressive {D1}/{D2} Andean deformation. D2 deformation is marked by outcrop-to 10 km-scale south-southwest-vergent folds. Late Cretaceous-Tertiary brittle-ductile and brittle left-lateral strike-slip faults and shear zones crosscut all {D1}/{D2} structures. Although limited structural evidence for extensional tectonics was documented in this study, apparent normal offsets across both arms of the Beagle Channel and previously documented field evidence for extension from other areas in Cordillera Darwin suggest that transtensional displacements also may have occurred in southern Cordillera Darwin during the Late Cretaceous-Early Tertiary. Cordillera Darwin's position within the evolving Patagonian Orocline adjacent to an evolving Mesozoic-Cenozoic left-lateral transform boundary between the South American and Antarctic plates, and later the South American and Scotia plates, necessitates consideration of the possible effects of regional counterclockwise rotation on development of structures. Regional counterclockwise rotation of Cordillera Darwin may have controlled the temporal and spatial transition of deformational regimes within Cordillera Darwin. Exhumation of the metamorphic core of Cordillera Darwin during the Late Cretaceous-Early Tertiary is

  4. Millennial scale precipitation changes over Easter Island (Southern Pacific) during MIS 3: Inter-hemispheric connections during North Atlantic abrupt cold events

    NASA Astrophysics Data System (ADS)

    Margalef, Olga; Cacho, Isabel; Pla-Rabes, Sergi; Cañellas-Boltà, Núria; Pueyo, Juan Jose; Sáez, Alberto; Valero-Garcés, Blas L.; Giralt, Santiago

    2013-04-01

    Marine Isotope Stage (MIS) 3 climate has been globally characterized by the occurrence of millennial-scale climate variations defined over North Atlantic as Dansgaard-Oeschger and Heinrich events. Despite climate variability has been broadly explored over North Atlantic records, the response of the tropical and subtropical latitudes, especially in the Southern Hemisphere, still remains as a matter of debate. Rano Aroi peat record (Easter Island, Chile, 27°S) provides a unique opportunity to understand Southern Pacific atmospheric and oceanic changes during these stadial-interstadial transitions because of its exceptional location on the interplay of the South Pacific Convergence Zone (SPCZ), the Intertropical Convergence Zone (ITCZ), the South Pacific Anticyclone (SPA) and the Southern Westerlies (SW). Rano Aroi record contains 8 main enhanced precipitation events between 70 and 40 kyr BP that can be correlated with the timing of Heinrich events 5, 5a and 6 as well as other cold stadials. These humid events are also present in other Southern Hemisphere continental sites and correspond to dry periods on Northern Hemisphere records. This opposite hydrologic trend has been explained by the latitudinal migration of ITCZ and has been supported by several climatic models. As Easter Island precipitation is mainly dependent on SPCZ storm track belt activity, we suggest that the southern migration of the ITCZ is associated to an expansion of SPCZ to the east. This process should be intimately related to a weakening of the Walker circulation, which is further supported by an estimation of d18Osw gradient along the equator for the same time period. Consequently, atmospheric and oceanic responses during these cold stadials and Heinrich events might lead to a configuration that resembles the warm ENSO state over Southern Pacific, as previously suggested by some global climatic models. Rano Aroi record clearly points out that shifts in hydrological cycle in tropical Southern

  5. Current Tectonics of Northern Vancouver Island, Southern Queen Charlotte Islands and the Adjacent Mainland

    NASA Astrophysics Data System (ADS)

    Sabine, H.; Mazzotti, S.; Hyndman, R. D.

    2009-05-01

    The area south of the Queen Charlotte Islands and north of Vancouver Island is characterized by the transition from the Cascadia subduction zone to the Queen Charlotte transform fault zone. The tectonic setting involves the Pacific, North American, Juan de Fuca, and Explorer plates, and the Winona block, as well as the Queen Charlotte and Revere-Dellwood-Wilson faults, Explorer ridge, Nootka fault, and Cascadia subduction zone. On the basis of GPS campaign data from 1993 to 2008 we derive a crustal velocity field for North Vancouver Island and the adjacent mainland. This velocity data is the basis for interpretation of the tectonics of the transition from the convergent to transform boundaries. Our GPS data show significant shear velocities in the Bella Coola region, ~250 km inland from the Queen Charlotte fault, although there is no seismic activity in the area. We use geodynamic models to better understand the discrepancy between the GPS data and the seismic data. We use the GPS velocities to determine whether the measured deformation rates of northernmost Vancouver Island, related to its interaction with the Explorer Plate and possibly the Queen Charlotte transform margin, are transient or permanent. Geodynamic models are used to find out if deformation in the region including North Vancouver Island, Queen Charlotte Islands, and the adjacent mainland (Coast Shear Zone) is transient or long-term. To constrain the model, we use the rheology and structure of the region, with reasonable values for elastic thickness and viscosity. Two end-member models describing how the Pacific/North America plate convergence is accommodated off the Queen Charlotte Islands have been developed by others. They assume either internal crustal shortening or underthrusting of the Pacific plate. With the new GPS data we can further investigate which model explains the tectonic situation more appropriately. An earlier model strongly suggests an underthrusting fault fully locked down to 14

  6. Stratigraphic framework maps of the nearshore area of southern Long Island from Fire Island to Montauk Point, New York

    USGS Publications Warehouse

    Foster, David S.; Swift, B. Ann; Schwab, William C.

    1999-01-01

    The maps presented in this report (depth to Coastal Plain unconformity, Quaternary sediment thickness, paleochannel thickness, and modern sand thickness) are helpful for determining sand-resource availability for beach nourishment programs and understanding the influence that the inner-shelf framework of southern Long Island has on coastal processes and evolution. The maps showing structure of the Coastal Plain unconformity and thickness of overlying Quaternary sediment delineate the framework of the coastal region. The map showing the distribution and thickness of paleochannel fill indicates areas not suitable as sources for beach nourishment, assuming the channels contain muddy estuarine deposits. The areas between channels are Pleistocene glacial deposits and probably consist of coarse sediment that may be suitable for beach nourishment. These coarser-grained glacial deposits are the source for modern sand deposits. The modern sands have been reworked primarily from glacial deposits and a Cretaceous outcrop off Watch Hill. These reworked deposits provide well-sorted clean sand that have and will provide nourishment for southern Long Island beaches.

  7. Crustal structure north of the Taiping Island (Itu Aba Island), southern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Chang, Jih-Hsin; Hsieh, Hsien-Hsiang; Mirza, Arif; Chang, Sung-Ping; Hsu, Ho-Han; Liu, Char-Shine; Su, Chih-Chieh; Chiu, Shye-Donq; Ma, Yu-Fang; Chiu, Ying-Hui; Hung, Hau-Ting; Lin, Yen-Chun; Chiu, Chien-Hsuan

    2017-07-01

    Based on the multi-channel seismic (MCS) and gravity data offshore north of Taiping Island (Itu Aba Island) in the Spratly Islands (Nansha Islands), we revisited the crustal structures in the northern part of the southern margin of the Southwest (SW) Sub-basin of the South China Sea (SCS). The MCS data suggest that the basement structural highs in the southwest margin of the SCS are dominated by both fault blocks and volcanic basement structures that probably formed along with the basement faults. The gravity modeling results reveal that these volcanic basement structures were probably associated with the high velocity or density lower crust (HVDLC), suggesting that the southern margin of the SW Sub-basin serves as an intermediate margin. Based on the tectonic features in the SCS margins, including (1) the transition between the magma-poor margins of the Northwest (NW) Sub-basin and intermediate margins of the East and SW Sub-basins; (2) the cessation of the seafloor spreading in the NW Sub-basin being succeeded by a major ridge jump event, which was very likely to reflect an active mantle upwelling event; (3) the extensive distribution of the HVDLC beneath in the well-investigated northern margin of the East Sub-basin and as explored in the SW Sub-basin in this study; and (4) basement faulting and volcanism shown in this study that may be related to the HVDLC and hyper-extension, we proposed a conceptual model to interpret the origin of the HVDLC in the southern margin of the SW Sub-basin. The margin of the SCS basin was magma-poor at the time it occurred. An active mantle upwelling event caused by small-scale mantle convection, possibly related to the influence of the nascent Hainan mantle plume, was formed subsequently, resulting in a southward ridge jump and the HVDLC beneath the current margins of the East and SW Sub-basins. The East and SW Sub-basins continued to spread, latitudinally dividing their HVDLCs as the margins separated accordingly. Afterwards, the

  8. Southern Costa Rica: an Island-arc Segment That Behaves Like a Doubly Vergent Orogen

    NASA Astrophysics Data System (ADS)

    Brandes, C.; Winsemann, J.

    2007-12-01

    Southern Central America is a Mesosoic/Cenozoic island-arc that evolved from the subduction of the Farallón Plate below the Caribbean Plate. The southern Costa Rican land-bridge comprises deformed fore-arc and back-arc basins in the west and east, respectively, separated by the up to 3.8 km high Talamanca Range. The structure of the southern Central American island-arc is similar to doubly vergent and asymmetric orogens. The deformed fore-arc basin in the west and the Limon fold-and-thrust belt in the east can be interpreted as pro-wedge and retro-wedge, respectively. The Talamanca Range represents the uplifted block in between. The pro-wedge is wider and has a lower slope angle than the retro-wedge. The uplift of the Talamanca Range is probably related to a system of conjugate shear zones. Precipitation is unevenly distributed, with orographic effects concentrating precipitation in SW Costa Rica, which has caused pro-wedge denudation, leading to exhumation of granitic rocks at in the interior of the mountain range. The large-scale structure of the Central American island-arc in southern Costa Rica can be described using models of continental collision zones. Previous studies attributed the deformation and uplift pattern to the subduction/collision of the Cocos Ridge. Another reasonable driving mechanism for the evolution of such an orogen in an oceanic island-arc setting is the basal traction due to long-term subduction of the Cocos Plate at a very low angle.

  9. Postglacial Records of Southern Hemisphere Westerly Wind Variability From the New Zealand Subantarctic Auckland Islands

    NASA Astrophysics Data System (ADS)

    Moy, C. M.; Vandergoes, M.; Gilmer, G. J.; Nichols, J. E.; Dagg, B. J.; Wilson, G. S.; Browne, I. M.; Curtin, L. G.; Aebig, C.; McGlone, M.

    2015-12-01

    The strength and latitudinal position of the Southern Hemisphere westerly winds (SHWW) play a fundamental role in influencing mid latitude climate and carbon dioxide exchange between the Southern Ocean and the atmosphere. Despite their importance, our understanding of past changes in the SHWW is limited by few paleoclimate records from the modern wind maximum that are often not in agreement. The New Zealand subantarctic Auckland Islands are located within the core of the modern wind belt (50°S) where the ocean-atmospheric linkages between the Antarctic and middle latitudes are strong. In contrast to other subantarctic islands on the Campbell Plateau, the Auckland Islands have protected fjord sub-basins, deep lakes, and peatlands that are advantageous for the development of high-resolution paleoclimate records. We will present ongoing work towards the establishment of multi-proxy and multi-site reconstructions of past SHWW variability from the Auckland Islands. Modern process and paleoclimate results from two research cruises in 2014 and 2015 suggest that in lacustrine and fjord settings, the degree of water column mixing, the stable isotopic composition of n-alkanes and benthic foraminifera, the influx of terrestrial organic matter are good indicators of wind-induced mixing of the water column or precipitation-driven erosion within catchments. In ombrotrophic peatlands, hydrogen isotope ratios of specific organic molecules allow reconstructions of the hydrogen isotope ratios of precipitation, which is related to precipitation source area and the latitudinal position of the SHWW. Using macrofossil counts paired with abundances of leaf wax biomarkers, we are able to estimate the moisture balance at peatland coring sites. Early results indicate an overall strengthening of the SHWW at the Auckland Islands through the Holocene. We will discuss these results within the context of complimentary records developed from New Zealand and southern South America to ultimately

  10. Imaging Canary Island hotspot material beneath the lithosphere of Morocco and southern Spain

    NASA Astrophysics Data System (ADS)

    Miller, Meghan S.; O'Driscoll, Leland J.; Butcher, Amber J.; Thomas, Christine

    2015-12-01

    The westernmost Mediterranean has developed into its present day tectonic configuration as a result of complex interactions between late stage subduction of the Neo-Tethys Ocean, continental collision of Africa and Eurasia, and the Canary Island mantle plume. This study utilizes S receiver functions (SRFs) from over 360 broadband seismic stations to seismically image the lithosphere and uppermost mantle from southern Spain through Morocco and the Canary Islands. The lithospheric thickness ranges from ∼65 km beneath the Atlas Mountains and the active volcanic islands to over ∼210 km beneath the cratonic lithosphere in southern Morocco. The common conversion point (CCP) volume of the SRFs indicates that thinned lithosphere extends from beneath the Canary Islands offshore southwestern Morocco, to beneath the continental lithosphere of the Atlas Mountains, and then thickens abruptly at the West African craton. Beneath thin lithosphere between the Canary hot spot and southern Spain, including below the Atlas Mountains and the Alboran Sea, there are distinct pockets of low velocity material, as inferred from high amplitude positive, sub-lithospheric conversions in the SRFs. These regions of low seismic velocity at the base of the lithosphere extend beneath the areas of Pliocene-Quaternary magmatism, which has been linked to a Canary hotspot source via geochemical signatures. However, we find that this volume of low velocity material is discontinuous along strike and occurs only in areas of recent volcanism and where asthenospheric mantle flow is identified with shear wave splitting analyses. We propose that the low velocity structure beneath the lithosphere is material flowing sub-horizontally northeastwards beneath Morocco from the tilted Canary Island plume, and the small, localized volcanoes are the result of small-scale upwellings from this material.

  11. [Eating habits and subjective well-being among university students in southern Chile].

    PubMed

    Schnettler, Berta; Denegri, Marianela; Miranda, Horacio; Sepúlveda, José; Orellana, Ligia; Paiva, Galo; Grunert, Klaus G

    2013-11-01

    Objetivo: Distinguir tipologías de estudiantes universitarios en el sur de Chile, en base a su nivel de satisfacción con la vida y la alimentación, y caracterizarlas según sus hábitos alimentarios dentro y fuera del lugar de residencia, aspectos asociados a la salud y características demográficas. Material y método: Se aplicó un cuestionario estructurado a una muestra no probabilística de 347 estudiantes de la Universidad de La Frontera, Temuco-Chile. El instrumento de recogida de información incluyó las escalas SWLS (Satisfaction with Life Scale), SWFL (Satisfaction with Food-related Life) y el ICVRS (Índice de calidad de vida relativo a la salud). Se consultaron los hábitos de consumo de alimentos dentro y fuera del lugar de residencia, el peso y estatura aproximada y, variables de clasificación demográfica. Resultados: Mediante análisis clúster se distinguieron tres tipologías de estudiantes con diferencias significativas en los puntajes de la SWLS y SWFL. Las tipologías difirieron en el número de días afectados por problemas de salud emocional, clasificación de su estado nutricional (IMC), auto percepción de su estado de salud, importancia de la alimentación para el bienestar personal, lugar de residencia durante el periodo de estudios, frecuencia de alimentación en el lugar donde vive y frecuencia de comidas a deshora. Conclusiones: La posibilidad de vivir con los padres durante el periodo de estudios universitarios se asocia con mejores hábitos de alimentación, mejor salud emocional y auto percepción de la salud, menor prevalencia de sobre peso y obesidad y, con una mayor satisfacción con la vida y la alimentación.

  12. Genetic and morphometric differentiation between island and mainland southern elephant seal populations.

    PubMed Central

    Hoelzel, A. R.; Campagna, C.; Arnbom, T.

    2001-01-01

    We compare genetic (both nuclear and mitochondrial) and morphometric measures between two putative populations of southern elephant seal (Mirounga leonina), and interpret the results in the context of data from mark-recapture and satellite-telemetric studies. One population is on the Argentine mainland, while the other is 2,400 km away on South Georgia island. We found pronounced differentiation at the mitochondrial DNA (mtDNA) control region that was distinct from the pattern of variation seen among island rookeries. Some morphometric characters and seven out of ten nuclear-DNA markers also showed differentiation between the island and mainland sites. Diversity at nuclear markers was high in both populations but mtDNA diversity was low in the mainland population, suggesting a founder event and little subsequent immigration of females. Morphological differences may suggest different selective environments at the two sites. PMID:11217905

  13. 10Be application to soil development on Marion Island, southern Indian Ocean

    NASA Astrophysics Data System (ADS)

    Haussmann, N.; Aldahan, A.; Boelhouwers, J.; Possnert, G.

    2010-04-01

    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 × 10 kyr ago. These conditions provide an interesting possibility for the assessment of 10Be accumulation rates and their application to soil erosion studies on the island. 10Be concentrations were measured in precipitation, soil profiles and an Azorella selago cushion plant. The data reveal a 10Be precipitation flux several times higher than model prediction. Estimation of the 10Be 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 10Be from the soil profile, an overestimated Holocene 10Be-flux or a delayed soil development history. Our results provide new data on 10Be concentrations from the sub-Antarctic islands and contribute towards enlarging the southern-hemisphere 10Be database.

  14. Person-to-Person Household and Nosocomial Transmission of Andes Hantavirus, Southern Chile, 2011

    PubMed Central

    Martinez-Valdebenito, Constanza; Calvo, Mario; Vial, Cecilia; Mansilla, Rita; Marco, Claudia; Palma, R. Eduardo; Vial, Pablo A.; Valdivieso, Francisca; Mertz, Gregory

    2014-01-01

    Andes hantavirus (ANDV) causes hantavirus cardiopulmonary syndrome in Chile and is the only hantavirus for which person-to-person transmission has been proven. We describe an outbreak of 5 human cases of ANDV infection in which symptoms developed in 2 household contacts and 2 health care workers after exposure to the index case-patient. Results of an epidemiologic investigation and sequence analysis of the virus isolates support person-to-person transmission of ANDV for the 4 secondary case-patients, including nosocomial transmission for the 2 health care workers. Health care personnel who have direct contact with ANDV case-patients or their body fluids should take precautions to prevent transmission of the virus. In addition, because the incubation period of ANDV after environmental exposure is longer than that for person-to-person exposure, all persons exposed to a confirmed ANDV case-patient or with possible environmental exposure to the virus should be monitored for 42 days for clinical symptoms. PMID:25272189

  15. Community response of zooplankton to oceanographic changes (2002-2012) in the central/southern upwelling system of Chile

    NASA Astrophysics Data System (ADS)

    Medellín-Mora, Johanna; Escribano, Ruben; Schneider, Wolfgang

    2016-03-01

    A 10-year time series (2002-2012) at Station 18 off central/southern Chile allowed us to study variations in zooplankton along with interannual variability and trends in oceanographic conditions. We used an automated analysis program (ZooImage) to assess changes in the mesozooplankton size structure and the composition of the taxa throughout the entire community. Oceanographic conditions changed over the decade: the water column became less stratified, more saline, and colder; the mixed layer deepened; and the oxygen minimum zone became shallower during the second half of the time series (2008-2012) in comparison with the first period (2002-2007). Both the size structure and composition of the zooplankton were significantly associated with oceanographic changes. Taxonomic and size diversity of the zooplankton community increased to the more recent period. For the second period, small sized copepods (<1 mm) decreased in abundance, being replaced by larger sized (>1.5 mm) and medium size copepods (1-1.5 mm), whereas euphausiids, decapod larvae, appendicularian and ostracods increased their abundance during the second period. These findings indicated that the zooplankton community structure in this eastern boundary ecosystem was strongly influenced by variability of the upwelling process. Thus, climate-induced forcing of upwelling trends can alter the zooplankton community in this highly productive region with potential consequences for the ecosystem food web.

  16. Deterministic Seismic Hazard Assessment for the Southern Peru and Northern Chile Segment of the Andean Subduction Zone

    NASA Astrophysics Data System (ADS)

    Shrivastava, M. N.; Fuentes, C.; Gonzalez, G.; Salazar, P.; Yanez, G. A.; Martin, J. C. D. L. L.; González-Carrasco, J. F.

    2015-12-01

    The coastal region of southern Peru and northern Chile is located in a mature seismic gap and expecting a great megathrust earthquake, which may release the seismic moment deficit accumulated since 1868 and 1877 respectively. One the most important question is how this seismic gap will break in the future. This question is not only important from a scientific point view but also it is relevant for seismic hazard assessment. In this contribution, we propose a methodology to identify the most suitable region for future earthquakes in a mature seismic gap. We adopt a deterministic approach by using some geophysical/geodetic parameters as b value, trench parallel gravity anomaly and interseismic coupling. These parameters represent a physical constraint for short/long term suitable regions for future great earthquakes. In order to weight the contribution of each parameter, we assume the short-long term seismic index (SLTS index), we perform a Monte Carlo simulation using as a calibration measurement the greatest earthquakes occurred in the region. In order to visualize the regional distribution of the SLTS index in the megathrust, we divide the fault in bins of 20 x 20 km. In each bin, we calculate the SLTS index and the moment deficit since the last greatest earthquake. Model results using this SLTS index highlight the most likely domains of short-long term asperities able to nucleate earthquakes in the region. The slip distribution of the Iquique 2014 earthquake validates the reliability of this SLTS index.

  17. Genetic diversity of terricolous Peltigera cyanolichen communities in different conservation states of native forest from southern Chile.

    PubMed

    Ramírez-Fernández, Lía; Zúñiga, Catalina; Méndez, Marco A; Carú, Margarita; Orlando, Julieta

    2013-12-01

    Decreasing quality of forest habitats is among the major factors leading to a loss of epiphytic lichen diversity. However, there is little information about how this factor influences the diversity of terricolous lichens, which do not grow over living trees and could be less susceptible to such disturbances. In this work we describe the genetic diversity of Peltigera terricolous cyanolichens and their cyanobiont (Nostoc) from three habitats at the Karukinka Natural Park (Tierra del Fuego, southern Chile), which represent different conservation states: native mature-forest (low disturbance intensity), native young-forest (medium disturbance intensity) and grassland (high disturbance intensity). In both forest contexts, a higher diversity and a higher number of unique OTUs (operational taxonomic units) were found. In contrast, in the grassland, the diversity was lower and the Peltigera species were mostly cosmopolitan. The presence of unique OTUs and the higher diversity of lichens in native forest areas highlight the importance of their preservation, indicating that decreasing forest quality also has a negative impact on terricolous lichens diversity.

  18. Low-temperature alteration of dredged volcanics from the Southern Chile Ridge: Additional information about early stages of seafloor weathering

    USGS Publications Warehouse

    Pichler, T.; Ridley, W.I.; Nelson, E.

    1999-01-01

    A suite of submarine volcanic rocks from the Southern Chile Ridge has been examined in order to investigate the early stages of low temperature alteration. Alteration in these samples proceeded as follows: (1) Fe-staining on sample surface and along fractures, (2) filling of vesicles with secondary material, (3) breakdown of glassy matrix, (4) breakdown of microcrystalline matrix, and (5) breakdown and replacement of olivine. Plagioclase and pyroxene were sometimes found to be slightly altered along internal fissures. Secondary or alteration phases generally showed high K (3-5 wt.%), Fe (30-70 wt.%) and low Al ( Rb > K. During initial stages of alteration the behavior of some trace elements such as rare-earth elements (REE), Ba, Zr, Hf, Ta, Nb, and Mo are solely controlled by the precipitation of Mn-rich Fe-oxyhydroxides. The preferred incorporation of Ce into Mn-rich Fe-oxyhydroxides may be a principal factor explaining the Ce depletion in seawater. We conclude that the earliest stages of submarine weathering are controlled by Eh and pH gradients between the rock and seawater. In the absence of a buffer, oxidation of ferrous iron causes a decrease in solution pH.

  19. Stratigraphy and chronology of late pleistocene reefs in the Southern Cook Islands, south Pacific

    NASA Astrophysics Data System (ADS)

    Woodroffe, Colin D.; Short, Stephen A.; Stoddart, David R.; Spencer, Tom; Harmon, Russell S.

    1991-03-01

    The Makatea Islands in the southern Cook Islands consist of a degraded volcanic core surrounded by emergent "makatea" limestones. While much of this reefal limestone is of Tertiary age, the seawardmost reefs are late Pleistocene. Last-interglacial reefs (oxygen isotope substage 5e) identified by U-series dating reach 12.2 m on Atiu (mean age of three samples 126,000 ± 5000 yr B.P.), 9.8 m on Mitiaro (mean age of five samples 119,000 ± 3000 yr B.P.), 10.0-12.7 m on Mauke (mean age of four samples 128,000 + 5000, -4,000 yr B.P.), and 14.5-20.0 m on Mangaia (mean age of four samples 115,000 ± 7000 yr B.P.). On Atiu, Mauke, and Mitiaro a lower reef unit has been identified, and is separated from the overlying substage 5e reef by a sharp discontinuity, often with a crust of coralline algae. U-series dating from Atiu and Mauke indicates that this is a stage 7 reef formed in the penultimate interglaciation. The Makatea Islands have emerged as a result of flexure of the lithosphere in response to loading by the Pleistocene volcanic island of Rarotonga. Isolated outcrops of makatea limestone on Rarotonga reach 3.5 m and are probably of substage 5e age. Elastic and viscoelastic models of lithospheric flexure predict that much of the compensatory movement should occur shortly after the emplacement of the load. However, the age and elevation of late Quaternary reefs on the southern Cook Islands, where a Pleistocene volcanic island has loaded relatively old ocean floor (>80 myr), indicate that differential uplift has been continuing over the last 250,000 yr.

  20. A New, Continuous 5400 Yr-long Paleotsunami Record from Lake Huelde, Chiloe Island, South Central Chile.

    NASA Astrophysics Data System (ADS)

    Kempf, P.; Moernaut, J.; Vandoorne, W.; Van Daele, M. E.; Pino, M.; Urrutia, R.; De Batist, M. A. O.

    2014-12-01

    After the last decade of extreme tsunami events with catastrophic damage to infrastructure and a horrendous amount of casualties, it is clear that more and better paleotsunami records are needed to improve our understanding of the recurrence intervals and intensities of large-scale tsunamis. Coastal lakes (e.g. Bradley Lake, Cascadia; Kelsey et al., 2005) have the potential to contain long and continuous sedimentary records, which is an important asset in view of the centennial- to millennial-scale recurrence times of great tsunami-triggering earthquakes. Lake Huelde on Chiloé Island (42.5°S), Chile, is a coastal lake located in the middle of the Valdivia segment, which is known for having produced the strongest ever instrumentally recorded earthquake in 1960 AD (MW: 9.5), and other large earthquakes prior to that: i.e. 1837 AD, 1737 AD (no report of a tsunami) and 1575 AD (Lomnitz, 1970, 2004, Cisternas et al., 2005). We present a new 5400 yr-long paleotsunami record with a Bayesian age-depth model based on 23 radiocarbon dates that exceeds all previous paleotsunami records from the Valdivia segment, both in terms of length and of continuity. 18 events are described and a semi-quantitative measure of the event intensity at the study area is given, revealing at least two predecessors of the 1960 AD event in the mid to late Holocene that are equal in intensity. The resulting implications from the age-depth model and from the semi-quantitative intensity reconstruction are discussed in this contribution.

  1. Analytical pyrolysis and stable isotope analyses reveal past environmental changes in coralloid speleothems from Easter Island (Chile).

    PubMed

    Miller, Ana Z; De la Rosa, José M; Jiménez-Morillo, Nicasio T; Pereira, Manuel F C; González-Pérez, José A; Calaforra, José M; Saiz-Jimenez, Cesareo

    2016-08-26

    This study comprises an innovative approach based on the combination of chromatography (analytical pyrolysis and pyrolysis compound-specific isotope analysis (Py-CSIA)), light stable isotopes, microscopy and mineralogy analyses to characterize the internal layering of coralloid speleothems from the Ana Heva lava tube in Easter Island (Chile). This multidisciplinary proxy showed that the speleothems consist of banded siliceous materials of low crystallinity with different mineralogical compositions and a significant contribution of organic carbon. Opal-A constitutes the outermost grey layer of the coralloids, whereas calcite and amorphous Mg hydrate silicate are the major components of the inner whitish and honey-brown layers, respectively. The differences found in the mineralogical, elemental, molecular and isotopic composition of these distinct coloured layers are related to environmental changes during speleothem development. Stable isotopes and analytical pyrolysis suggested alterations in the water regime, pointing to wetter conditions during the formation of the Ca-rich layer and a possible increase in the amount of water dripping into the cave. The trend observed for δ(15)N values suggested an increase in the average temperature over time, which is consistent with the so-called climate warming during the Holocene. The pyrolysis compound-specific isotope analysis of each speleothem layer showed a similar trend with the bulk δ(13)C values pointing to the appropriateness of direct Py-CSIA in paleoenvironmental studies. The δ(13)C values for n-alkanes reinforced the occurrence of a drastic environmental change, indicating that the outermost Opal layer was developed under drier and more arid environmental conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Distribution of birds and plants at the western and southern edges of the Madrean Sky Islands in Sonora, Mexico

    Treesearch

    Aaron D. Flesch; Lisa A. Hahn

    2005-01-01

    The western and southern edges of the Madrean Sky Island region are poorly defined and have received little study. After exploring mountains in these areas, we documented range extensions and additional records for several species of interest. Although many of these disjunct mountains have not been considered Sky Islands, their flora and fauna are similar to other...

  3. Ecology and spatial pattern of cyanobacterial community island patches in the Atacama Desert, Chile

    NASA Astrophysics Data System (ADS)

    Warren-Rhodes, Kimberley A.; Dungan, Jennifer L.; Piatek, Jennifer; Stubbs, Kristin; Gómez-Silva, Benito; Chen, Yong; McKay, Christopher P.

    2007-12-01

    Plant landscape ecology studies have been carried out for decades and are fundamental to biological research. In contrast, few corollary spatial landscape studies exist for microorganisms, particularly in extreme environments. To address this gap, we mapped the abundance and spatial distribution of photoautotrophs colonizing translucent rocks in several sites in the Atacama Desert, including the hyperarid core. Cyanobacterial communities at all sites are predominantly (≥75%) `perilithic' (confined to the periphery of rocks) and occur in non-random spatial patterns ("island patches") at multiple scales. Cyanobacterial patches typically contain 1-5 colonized rocks but in some cases support much higher numbers. A high resolution mapping of a single 18-m2 rock cluster at the Aguas Calientes study site (25°S, 69°W) revealed colonization of 5.2% (49 of 948 quartz rocks) and showed colonized rocks to be much larger (˜2X) than the available mean rock size. Ripley's K and point pattern analyses show that quartz rocks are not "selected" or occupied by cyanobacteria randomly, but that non-random processes distinct from those creating the background rock pattern must be invoked to explain microbial patchiness in the Atacama Desert. These processes include physical controls (rock size/orientation, microtopography) that reflect resource (water) limitations, and biological dispersal via rainfall, fog and wind.

  4. Dynamics of a large, restless, rhyolitic magma system at Laguna del Maule, southern Andes, Chile

    USGS Publications Warehouse

    Singer, Brad S.; Andersen, Nathan L.; Le Mével, Hélène; Feigl, Kurt L.; DeMets, Charles; Tikoff, Basil; Thurber, Clifford H.; Jicha, Brian R.; Cardonna, Carlos; Córdova, Loreto; Gil, Fernando; Unsworth, Martyn J.; Williams-Jones, Glyn; Miller, Craig W.; Fierstein, Judith; Hildreth, Edward; Vazquez, Jorge A.

    2014-01-01

    Explosive eruptions of large-volume rhyolitic magma systems are common in the geologic record and pose a major potential threat to society. Unlike other natural hazards, such as earthquakes and tsunamis, a large rhyolitic volcano may provide warning signs long before a caldera-forming eruption occurs. Yet, these signs—and what they imply about magma-crust dynamics—are not well known. This is because we have learned how these systems form, grow, and erupt mainly from the study of ash flow tuffs deposited tens to hundreds of thousands of years ago or more, or from the geophysical imaging of the unerupted portions of the reservoirs beneath the associated calderas. The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007, the crust there has been inflating at an astonishing rate of at least 25 cm/yr. This unique opportunity to investigate the dynamics of a large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively under way is stimulating a new international collaboration. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ca. 20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. The next phase of this investigation seeks to enlarge the sets of geophysical and geochemical data and to use these observations in numerical models of system dynamics.

  5. [Acceptance of yoghurt with different functional ingredients among consumers in supermarkets in southern Chile].

    PubMed

    Schnettler, Berta; Shene, Carolina; Rubilar, Mónica; Miranda, Horacio; Sepúlveda, José; Denegri, Marianela; Lobos, Germán

    2010-12-01

    In view of the interest in the role of foodstuffs in improving wellbeing and health, the object of this study is to distinguish consumer typologies in Temuco, La Araucanía Region, Chile, according to their preferences for different functional ingredients, flavouring, colouring and price in yoghurt. A semi-structured survey was applied to 400 supermarket customers. The respondents ordered eight alternative yoghurts according to their preferences, with different functional ingredients (fibre, antioxidants), flavourings (sugar, sweetener), colouring (natural, artificial) and three price options, for a conjoint analysis with fractional factorial design. Variables affecting knowledge of "functional food" were evaluated using a binomial logit model. It was determined by conjoint analysis that in general a preference existed for yoghurt containing fibre, sweetener, natural colouring, and at the lowest price. Three typologies were distinguished by analysis of hierarchical conglomerates: the majority segment (48.8%) displayed a greater preference for fibre; the second (41.7%) also preferred fibre, but gave first priority to artificial colouring and preferred a higher price. The minority (9.5%) was the only segment to prefer antioxidants. The typologies differed significantly in satisfaction with their food-related life, knowledge of the function of fibre and presence of cancer and obesity in some member of the respondent's family. The binomial logit model was significant (P < 0.01), indicating that if the consumer has a job or has had access to information on functional foods, the probability increased of knowledge of what these mean. There was thus majority acceptance of yoghurt enriched with fibre and with added sweetener.

  6. Diet of the prehistoric population of Rapa Nui (Easter Island, Chile) shows environmental adaptation and resilience.

    PubMed

    Jarman, Catrine L; Larsen, Thomas; Hunt, Terry; Lipo, Carl; Solsvik, Reidar; Wallsgrove, Natalie; Ka'apu-Lyons, Cassie; Close, Hilary G; Popp, Brian N

    2017-10-01

    The Rapa Nui "ecocide" narrative questions whether the prehistoric population caused an avoidable ecological disaster through rapid deforestation and over-exploitation of natural resources. The objective of this study was to characterize prehistoric human diets to shed light on human adaptability and land use in an island environment with limited resources. Materials for this study included human, faunal, and botanical remains from the archaeological sites Anakena and Ahu Tepeu on Rapa Nui, dating from c. 1400 AD to the historic period, and modern reference material. We used bulk carbon and nitrogen isotope analyses and amino acid compound specific isotope analyses (AA-CSIA) of collagen isolated from prehistoric human and faunal bone, to assess the use of marine versus terrestrial resources and to investigate the underlying baseline values. Similar isotope analyses of archaeological and modern botanical and marine samples were used to characterize the local environment. Results of carbon and nitrogen AA-CSIA independently show that around half the protein in diets from the humans measured came from marine sources; markedly higher than previous estimates. We also observed higher δ(15) N values in human collagen than could be expected from the local environment. Our results suggest highly elevated δ(15) N values could only have come from consumption of crops grown in substantially manipulated soils. These findings strongly suggest that the prehistoric population adapted and exhibited astute environmental awareness in a harsh environment with nutrient poor soils. Our results also have implications for evaluating marine reservoir corrections of radiocarbon dates. © 2017 Wiley Periodicals, Inc.

  7. Urban airborne matter in central and southern Chile: Effects of meteorological conditions on fine and coarse particulate matter

    NASA Astrophysics Data System (ADS)

    Yáñez, Marco A.; Baettig, Ricardo; Cornejo, Jorge; Zamudio, Francisco; Guajardo, Jorge; Fica, Rodrigo

    2017-07-01

    Air pollution is one of the major global environmental problems affecting human health and life quality. Many cities of Chile are heavily polluted with PM2.5 and PM10, mainly in the cold season, and there is little understanding of how the variation in particle matter differs between cities and how this is affected by the meteorological conditions. The objective of this study was to assess the effect of meteorological variables on respirable particulate matter (PM) of the main cities in the central-south valley of Chile during the cold season (May to August) between 2014 and 2016. We used hourly PM2.5 and PMcoarse (PM10- PM2.5) information along with wind speed, temperature and relative humidity, and other variables derived from meteorological parameters. Generalized additive models (GAMs) were fitted for each of the eight cities selected, covering a latitudinal range of 929 km, from Santiago to Osorno. Great variation in PM was found between cities during the cold months, and that variation exhibited a marked latitudinal pattern. Overall, the more northerly cities tended to be less polluted in PM2.5 and more polluted in PMcoarse than the more southerly cities, and vice versa. The results show that other derived variables from meteorology were better related with PM than the use of traditional daily means. The main variables selected with regard to PM2.5 content were mean wind speed and minimum temperature (negative relationship). Otherwise, the main variables selected with regard to PMcoarse content were mean wind speed (negative), and the daily range in temperature (positive). Variables derived from relative humidity contributed differently to the models, having a higher effect on PMcoarse than PM2.5, and exhibiting both negative and positive effects. For the different cities the deviance explained by the GAMs ranged from 37.6 to 79.1% for PM2.5 and from 18.5 to 63.7% for PMcoarse. The percentage of deviance explained by the models for PM2.5 exhibited a

  8. Influence of native forest cover on water yield in southern Chile: a comparative study of small watersheeds

    NASA Astrophysics Data System (ADS)

    Alvarez-Garretón, Camila; McPhee, James; Little, Christian; Lara, Antonio

    2010-05-01

    In this work we compare water yield in five small watersheds (surface area from 7 to 70 hectares) with different native forest cover, located in Southern Chile (39.5° Lat S). Forest covers include unmanaged second-growth forest of deciduous Nothofagus obliqua - Nothofagus nervosa ("Rsm", 7,4 ha), thinned second-growth forest of deciduous N. obliqua - N. nervosa with 35% of basal area extraction ("Rcm", 12,6 ha), altered evergreen old-growth forest dominated by Laurelia philippiana ("Tran", 7,5 ha), pristine old-growth forest of Nothofagus dombeyi ("Enc", 72,1 ha) and grassland as a control ("Prad", 12,3 ha). It is expected that differences in water yield are related mainly to differences in native forest structure, given that all watersheds have similar geomorphology and are located close to each other. We monitored daily streamflow and precipitation during four hydrological years (April 2003 through Dec 2006). Data were collected on each watershed and analyzed, first by recession curve classification, then by separating base flow and direct runoff. Subsequently, storm events were individualized, in order to isolate the effect of different antecedent soil moisture conditions. Variations in hydrograph recession curves as well as rainfall-runoff coefficients are analyzed in relation to differences in land cover type, storm magnitude and duration, antecedent soil moisture and presence of leafs. In agreement with the literature, all forested watersheds consume more water than a grassland watershed, but display a slower release of soil water storage. On the other hand, results show that managed forest basins yield more total, direct and base runoff in comparison to unmanaged watersheds. Further, unmanaged natural forests display flatter recession curves, implying a longer duration of base flow after storm events. This behavior has important implications for valuation and management of water yield, as an Ecosystem Service of native forest in Chile; it suggests that it

  9. Airborne dust transport to the eastern Pacific Ocean off southern California: Evidence from San Clemente Island

    USGS Publications Warehouse

    Muhs, D.R.; Budahn, J.; Reheis, M.; Beann, J.; Skipp, G.; Fisher, E.

    2007-01-01

    Islands are natural dust traps, and San Clemente Island, California, is a good example. Soils on marine terraces cut into Miocene andesite on this island are clay-rich Vertisols or Alfisols with vertic properties. These soils are overlain by silt-rich mantles, 5-20 cm thick, that contrast sharply with the underlying clay-rich subsoils. The silt mantles have a mineralogy that is distinct from the island bedrock. Silt mantles are rich in quartz, which is rare in the island andesite. The clay fraction of the silt mantles is dominated by mica, also absent from local andesite, and contrasts with the subsoils, dominated by smectite. Ternary plots of immobile trace elements (Sc-Th-La and Ta-Nd-Cr) show that the island andesite has a composition intermediate between average upper continental crust and average oceanic crust. In contrast, the silt and, to a lesser extent, clay fractions of the silt mantles have compositions closer to average upper continental crust. The silt mantles have particle size distributions similar to loess and Mojave Desert dust, but are coarser than long-range-transported Asian dust. We infer from these observations that the silt mantles are derived from airborne dust from the North American mainland, probably river valleys in the coastal mountains of southern California and/or the Mojave Desert. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. Examination of satellite imagery shows that easterly Santa Ana winds carry abundant dust to the eastern Pacific Ocean and the California Channel Islands. Airborne dust from mainland North America may be an important component of the offshore sediment budget in the easternmost Pacific Ocean, a finding of potential biogeochemical and climatic significance.

  10. Private and Public Schooling in the Southern Cone: A Comparative Analysis of Argentina and Chile. Occasional Paper.

    ERIC Educational Resources Information Center

    McEwan, Patrick J.

    Argentina and Chile have longstanding policies that give public subsidies to private schools. This paper uses data from 1997 from Argentina and Chile to compare the academic outcomes of seventh and eighth graders in public and private schools. Three types of private schools are analyzed: Catholic schools that are subsidized by the government,…

  11. The amphibians and reptiles of Mindanao Island, southern Philippines, II: the herpetofauna of northeast Mindanao and adjacent islands

    PubMed Central

    Sanguila, Marites B.; Cobb, Kerry A.; Siler, Cameron D.; Diesmos, Arvin C.; Alcala, Angel C.; Brown, Rafe M.

    2016-01-01

    Abstract We summarize all available amphibian and reptile species distribution data from the northeast Mindanao faunal region, including small islands associated with this subcenter of endemic vertebrate biodiversity. Together with all publicly available historical information from biodiversity repositories, we present new data from several major herpetological surveys, including recently conducted inventories on four major mountains of northeast Mindanao, and adjacent islands of Camiguin Sur, Dinagat, and Siargao. We present species accounts for all taxa, comment on unresolved taxonomic problems, and provide revisions to outdated IUCN conservation status assessments in cases where our new data significantly alter earlier classification status summaries. Together, our comprehensive analysis of this fauna suggests that the greater Mindanao faunal region possesses distinct subcenters of amphibian and reptile species diversity, and that until this area is revisited and its fauna and actually studied, with on-the-ground field work including targeted surveys of species distributions coupled to the study their natural history, our understanding of the diversity and conservation status of southern Philippine herpetological fauna will remain incomplete. Nevertheless, the northeast Mindanao geographical area (Caraga Region) appears to have the highest herpetological species diversity (at least 126 species) of any comparably-sized Philippine faunal subregion. PMID:27833422

  12. Southeast Alaskan shelf from southern tip of Baranof Island to Kayak Island: Currents, mixing and chlorophyll-a

    NASA Astrophysics Data System (ADS)

    Stabeno, P. J.; Bond, N. A.; Kachel, N. B.; Ladd, C.; Mordy, C. W.; Strom, S. L.

    2016-10-01

    During 2011 and 2013, an integrated ecosystem study was undertaken on the Southeast Alaska shelf and slope. As part of that study, a total of 8 moorings were deployed each year along the coast of Baranof and Chichagof Islands, in Cross Sound and at Icy Point. In addition, 18 satellite-tracked drifters were deployed during the two field years. The goals of this manuscript are to describe: the coastal currents in southeastern Alaska; the processes affecting them; and how the physics modify the nutrients and primary production in the region. Mixing in Cross Sound is an important source of nutrients for the shelf north of the sound, resulting in prolonged production during summer. While the Alaska Coastal Current is not a continuous feature along the entire Gulf of Alaska coast, it does exist from southern tip of Baranof Island to Cross Sound, and again northwest of Yakutat. The narrowness of this shelf coupled with the meanders and eddies in the Alaska Current result in large amounts of on-shelf flow of slope water and off-shelf flow of coastal water. While local currents and summer winds were similar in 2011 and 2013, 2011 was characterized by low chlorophyll-a concentrations throughout the spring-summer, while chlorophyll concentrations in 2013 were typical. The cause of this difference remains unclear, but bottom-up processes likely contributed to the low chlorophyll-a concentrations in 2011.

  13. Formation of gas discharging from Taketomi submarine hot spring off Ishigaki Island in the southern Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Toki, Tomohiro; Iwata, Daigo; Tsunogai, Urumu; Komatsu, Daisuke D.; Sano, Yuji; Takahata, Naoto; Hamasaki, Hiroshi; Ishibashi, Jun-ichiro

    2017-01-01

    Taketomi submarine hot spring lies off Ishigaki Island in the southern Ryukyu Islands and vents hot spring waters at temperatures up to 50 °C from the seafloor at a depth of 20 m. We investigated the chemical and isotopic composition of gases discharging from Taketomi hot spring. The gases were composed mainly of methane, with secondary nitrogen at higher than atmospheric concentration. Carbon and hydrogen isotope data suggest that the methane in the discharging gases was derived mainly from thermal decomposition of organic matter. Helium isotopes were enriched in 3He relative to the atmosphere, suggesting a supply of mantle-derived helium to the discharging gases. The mantle-derived gases transfer the deep-originated thermal energy to the hot spring and thermogenesis of organic matter. The hydrocarbons in the venting gas could be sourced from sedimentary rocks of the Yaeyama or Shimajiri Groups, or Yaeyama metamorphic rocks, and added to the ascending gases as they pass through those source rocks on their way to the surface. Because the Pleistocene rocks of the Ryukyu Group beneath the hot spring have been altered by the spring activity, the Taketomi hot spring began venting after the Pleistocene.

  14. The amphibians and reptiles of Mindanao Island, southern Philippines, II: the herpetofauna of northeast Mindanao and adjacent islands.

    PubMed

    Sanguila, Marites B; Cobb, Kerry A; Siler, Cameron D; Diesmos, Arvin C; Alcala, Angel C; Brown, Rafe M

    2016-01-01

    We summarize all available amphibian and reptile species distribution data from the northeast Mindanao faunal region, including small islands associated with this subcenter of endemic vertebrate biodiversity. Together with all publicly available historical information from biodiversity repositories, we present new data from several major herpetological surveys, including recently conducted inventories on four major mountains of northeast Mindanao, and adjacent islands of Camiguin Sur, Dinagat, and Siargao. We present species accounts for all taxa, comment on unresolved taxonomic problems, and provide revisions to outdated IUCN conservation status assessments in cases where our new data significantly alter earlier classification status summaries. Together, our comprehensive analysis of this fauna suggests that the greater Mindanao faunal region possesses distinct subcenters of amphibian and reptile species diversity, and that until this area is revisited and its fauna and actually studied, with on-the-ground field work including targeted surveys of species distributions coupled to the study their natural history, our understanding of the diversity and conservation status of southern Philippine herpetological fauna will remain incomplete. Nevertheless, the northeast Mindanao geographical area (Caraga Region) appears to have the highest herpetological species diversity (at least 126 species) of any comparably-sized Philippine faunal subregion.

  15. Molecular identification of Botrytis cinerea, Botrytis paeoniae and Botrytis pseudocinerea associated with gray mould disease in peonies (Paeonia lactiflora Pall.) in Southern Chile.

    PubMed

    Muñoz, Gastón; Campos, Felipe; Salgado, Daisy; Galdames, Rafael; Gilchrist, Lucy; Chahin, Gabriela; Andrade, Orlando

    2016-01-01

    In Chile, the peony is the most important ornamental flower exported from the country. Gray mould is a phytopathological problem of this crop. This disease is caused by Botrytis cinerea and Botrytis paeoniae. We carried out the first survey of Botrytis species associated with peony gray mould in Southern Chile to estimate the diversity of these pathogens. Diseased peony leaves were collected from seven locations in Southern Chile covering a distance of 300km. The Botrytis isolates obtained were studied by morphological and molecular methods. Finally, a PCR assay using primers based on the necrosis and ethylene-inducing protein gene (nep1) was used to specifically identify B. paeoniae. Seventeen isolates belonging to Botrytis genus were obtained, and all of them were pathogenic to peonies when inoculated in plants grown in a greenhouse. Morphological analyses showed that four isolates shared common characteristics, which distinguish them from the rest. Homology and phylogenetic analysis of G3PDH, as well as determination of the Bc-hch allele, allowed us to identify 12 isolates as B. cinerea, 4 as B. paeoniae and one isolate as Botrytis pseudocinerea. The PCR assay was found to be specific to B. paeoniae, amplifying a single band of 470bp. Three Botrytis species involved in peony gray mould disease are present in Chile. This is the first time that both B. paeoniae and B. pseudocinerea have been reported to be present in the country and also that they affect peonies. Finally, to our knowledge, the PCR based method herein described is the first of its kind to be used to identify B. paeoniae. Copyright © 2014 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  16. Baseline trace metals in seagrass, algae, and mollusks in a southern Tyrrhenian ecosystem (Linosa Island, Sicily).

    PubMed

    Conti, Marcelo Enrique; Bocca, Beatrice; Iacobucci, Marta; Finoia, Maria Grazia; Mecozzi, Mauro; Pino, Anna; Alimonti, Alessandro

    2010-01-01

    Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas.

  17. Photosynthetic Light Responses May Explain Vertical Distribution of Hymenophyllaceae Species in a Temperate Rainforest of Southern Chile.

    PubMed

    Parra, María José; Acuña, Karina I; Sierra-Almeida, Angela; Sanfuentes, Camila; Saldaña, Alfredo; Corcuera, Luis J; Bravo, León A

    2015-01-01

    Some epiphytic Hymenophyllaceae are restricted to lower parts of the host (< 60 cm; 10-100 μmol photons m(-2) s(-1)) in a secondary forest of Southern Chile; other species occupy the whole host height (≥ 10 m; max PPFD > 1000 μmol photons m(-2) s(-1)). Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution. We determined light tolerance of Hymenoglossum cruentum and Hymenophyllum dentatum by measuring gas exchange, PSI and PSII light energy partitioning, NPQ components, and pigment contents. H. dentatum showed lower maximum photosynthesis rates (A max) than H. cruentum, but the former species kept its net rates (An) near Amax across a wide light range. In contrast, in the latter one, An declined at PPFDs > 60 μmol photons m(-2) s(-1). H. cruentum, the shadiest plant, showed higher chlorophyll contents than H. dentatum. Differences in energy partitioning at PSI and PSII were consistent with gas exchange results. H. dentatum exhibited a higher light compensation point of the partitioning of absorbed energy between photochemical Y(PSII) and non-photochemical Y(NPQ) processes. Hence, both species allocated energy mainly toward photochemistry instead of heat dissipation at their light saturation points. Above saturation, H. cruentum had higher heat dissipation than H. dentatum. PSI yield (YPSI) remained higher in H. dentatum than H. cruentum in a wider light range. In both species, the main cause of heat dissipation at PSI was a donor side limitation. An early dynamic photo-inhibition of PSII may have caused an over reduction of the Qa+ pool decreasing the efficiency of electron donation to PSI. In H. dentatum, a slight increase in heat dissipation due to acceptor side limitation of PSI was observed above 300 μmol photons m(-2)s(-1). Differences in photosynthetic responses to light suggest that light tolerance and species plasticity could explain their contrasting vertical distribution.

  18. Photosynthetic Light Responses May Explain Vertical Distribution of Hymenophyllaceae Species in a Temperate Rainforest of Southern Chile

    PubMed Central

    Parra, María José; Acuña, Karina I.; Sierra-Almeida, Angela; Sanfuentes, Camila; Saldaña, Alfredo; Corcuera, Luis J.; Bravo, León A.

    2015-01-01

    Some epiphytic Hymenophyllaceae are restricted to lower parts of the host (<60 cm; 10–100 μmol photons m-2 s-1) in a secondary forest of Southern Chile; other species occupy the whole host height (≥10 m; max PPFD >1000 μmol photons m-2 s-1). Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution. We determined light tolerance of Hymenoglossum cruentum and Hymenophyllum dentatum by measuring gas exchange, PSI and PSII light energy partitioning, NPQ components, and pigment contents. H. dentatum showed lower maximum photosynthesis rates (Amax) than H. cruentum, but the former species kept its net rates (An) near Amax across a wide light range. In contrast, in the latter one, An declined at PPFDs >60 μmol photons m-2 s-1. H. cruentum, the shadiest plant, showed higher chlorophyll contents than H. dentatum. Differences in energy partitioning at PSI and PSII were consistent with gas exchange results. H. dentatum exhibited a higher light compensation point of the partitioning of absorbed energy between photochemical Y(PSII) and non-photochemical Y(NPQ) processes. Hence, both species allocated energy mainly toward photochemistry instead of heat dissipation at their light saturation points. Above saturation, H. cruentum had higher heat dissipation than H. dentatum. PSI yield (YPSI) remained higher in H. dentatum than H. cruentum in a wider light range. In both species, the main cause of heat dissipation at PSI was a donor side limitation. An early dynamic photo-inhibition of PSII may have caused an over reduction of the Qa+ pool decreasing the efficiency of electron donation to PSI. In H. dentatum, a slight increase in heat dissipation due to acceptor side limitation of PSI was observed above 300 μmol photons m-2s-1. Differences in photosynthetic responses to light suggest that light tolerance and species plasticity could explain their contrasting vertical distribution. PMID:26699612

  19. Increased water use efficiency but contrasting tree growth patterns in Fitzroya cupressoides forests of southern Chile during recent decades

    NASA Astrophysics Data System (ADS)

    Urrutia-Jalabert, Rocío.; Malhi, Yadvinder; Barichivich, Jonathan; Lara, Antonio; Delgado-Huertas, Antonio; Rodríguez, Carmen Gloria; Cuq, Emilio

    2015-12-01

    Little is known about how old-growth and massive forests are responding to environmental change. We investigated tree-ring growth and carbon isotopes of the long-lived and high biomass Fitzroya cupressoides in two stands growing in contrasting environmental conditions in the Coastal Range (~300 years old) and Andean Cordilleras (>1500 years old) of southern Chile. The interannual variability in δ13C was assessed for the period 1800-2010, and changes in discrimination and intrinsic water use efficiency (iWUE) were evaluated in relation to changes in climate and tree-ring growth during the last century. 13C discrimination has significantly decreased, and iWUE has increased since the 1900s in both sites. However, these trends in isotopic composition have been accompanied by different growth patterns: decreasing growth rates in the Coastal Range since the 1970s and increasing growth rates in the Andes since the 1900s. Trees growing in the Coastal Range have become more efficient in their use of water, probably due to reduced stomatal conductance caused by increases in CO2 and warming. Trees growing in the Andes have also become more water use efficient, but this has been likely due to increased photosynthetic rates. Fitzroya forests, including particularly old-growth stands, are responding to recent environmental changes, and their response has been site dependent. The growth of forests under a more Mediterranean climate influence and restrictive soil conditions in the Coastal Range has been more negatively affected by current warming and drying; while the growth of old stands in the wet Andes has been positively affected by changes in climate (decreasing cloudiness) and increasing CO2. Permanent monitoring of these endangered forests under ongoing environmental changes is needed in order to reassure the long-term preservation of this millennial-aged species.

  20. North Pecan Island field: a mature trend discovery in Miocene of southern Louisiana

    SciTech Connect

    Bauer, A.G.; McCormick, J.A.

    1985-02-01

    The Exxon 1 M.J. Epley discovery well for North Pecan Island field was completed in early 1982 as a discovery of significant new gas and condensate reserves in the mature Miocene trend of south Louisiana. The field is located in Vermilion Parish within a large megablock between 2 major down-to-the basin growth-fault systems and is on the southern end of a south-plunging structural nose. Traps in 2 fault segments are formed in southeasterly dipping beds upthrown to 2 north dipping, sealing faults. Six separate Robulus chambersi sandstones contain gas and condensate reserves. Major gas and condensate reserves from sandstone reservoirs in the R. chambersi section were discovered in the mid-1960s 3.3 mi. west in the Pecan island field and in the North Freshwater Bayou field, 5 mi northeast of the North Pecan Island field discovery. Several earlier dry holes just north of the discovery were drilled seeking to extend production from the upstructure Fire Island field (3 mi north), which produced a limited amount of gas and condensate from R. chambersi sandstones. Extensive structural and isopach mapping, aided by new high-resolution seismic data, revealed the North Pecan Island prospect to be structural high to production at Pecan Island and that the prospective section was deposited over a growing paleostructure. Four wells have been completed to date in the field, with flow rates as high as 30 MMCFGB. Current estimates place the new field recoverable at approximately 250 bcf of gas and 6 million bbl condensate.

  1. Chemosynthetic trophic support for the benthic community at an intertidal cold seep site at Mocha Island off central Chile

    NASA Astrophysics Data System (ADS)

    Sellanes, Javier; Zapata-Hernández, Germán; Pantoja, Silvio; Jessen, Gerdhard L.

    2011-12-01

    We analyzed C and N stable isotope ratios of benthic fauna and their potential food sources at an intertidal methane seep site and a control site without emanation at Mocha Island (central Chile). The objective was to trace the origin of the main food sources used by the local heterotrophic fauna, based on the hypothesis that chemosynthetic production could be partially fueling the local food web at the seep site. Food sources sampled at both sites included macroalgae, particulate organic matter and bacteria-like filaments found growing over the red algae Gelidium lingulatum within the areas of active methane release. At the control site, located 11 km away from the gas emanation, fauna exhibited moderate δ 13C values ranging from -16.2‰ (in a nereid polychaete) to -14.8‰ (in a cirolanid isopod), which were consistent with those of the potential photosynthetic food sources sampled at this site (-20.2 to -16.5‰). δ 13C values of the photosynthetic food sources at the seep site similarly ranged between -25.4 and -17.9‰. However, a portion of the animals at this site were consistently more 13C-depleted, with δ 13C values close to that of the seeping methane (-43.8‰) and the bacteria-like filaments (-39.2 ± 2.5‰) also collected at this site. Specific examples were the Marphysa sp. polychaetes (δ 13C = -44.7 ± 0.6‰), the Schistomeringos sp. dorvilleid polychaetes (δ 13C = -42.9‰), and the tanaid crustacean Zeuxo marmoratus (δ 13C = -37.3 ± 0.2‰). The significantly higher δ 13C values of the herbivorous gastropod Tegula atra at the seep site (-29.3 ± 3.1‰) than at the control site (-12.6 ± 0.3‰) also indicated differences among sites of the preferred carbon sources of this species. Mixing model estimates indicate that at the seep site bacteria-like filaments could be contributing up to ˜60% of the assimilated diet of selected invertebrates. Furthermore, several indicators of trophic structure, based in isotopic niche metrics, indicate a

  2. Low functional richness and redundancy of a predator assemblage in native forest fragments of Chiloe island, Chile.

    PubMed

    Farias, Ariel A; Jaksic, Fabian M

    2011-07-01

    1. Changes in land use and habitat fragmentation are major drivers of global change, and studying their effects on biodiversity constitutes a major research programme. However, biodiversity is a multifaceted concept, with a functional component linking species richness to ecosystem function. Currently, the interaction between functional and taxonomic components of biodiversity under realistic scenarios of habitat degradation is poorly understood. 2. The expected functional richness (FR)-species richness relationship (FRSR) is positive, and attenuated for functional redundancy in species-rich assemblages. Further, environmental filters are expected to flatten that association by sorting species with similar traits. Thus, analysing FRSR can inform about the response of biodiversity to environmental gradients and habitat fragmentation, and its expected functional consequences. 3. Top predators affect ecosystem functioning through prey consumption and are particularly vulnerable to changes in land use and habitat fragmentation, being good indicators of ecosystem health and suitable models for assessing the effects of habitat fragmentation on their FR. 4. Thus, this study analyses the functional redundancy of a vertebrate predator assemblage at temperate forest fragments in a rural landscape of Chiloe island (Chile), testing the existence of environmental filters by contrasting an empirically derived FRSR against those predicted from null models, and testing the association between biodiversity components and the structure of forest fragments. 5. Overall, contrasts against null models indicate that regional factors determine low levels of FR and redundancy for the vertebrate predator assemblage studied, while recorded linear FRSR indicates proportional responses of the two biodiversity components to the structure of forest fragments. Further, most species were positively associated with either fragment size or shape complexity, which are highly correlated. This, and the

  3. Comparative study of lahars generated by the 1961 and 1971 eruptions of Calbuco and Villarrica volcanoes, Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Castruccio, Angelo; Clavero, Jorge; Rivera, Andrés

    2010-02-01

    The Villarrica and Calbuco volcanoes, of the Andean Southern Volcanic Zone, are two of the most active volcanoes in Chile and have erupted several times in the XX century. The 1961 eruption at Calbuco volcano generated lahars on the North, East and Southern flanks, while the 1971 eruption at Villarrica volcano generated lahars in almost all the drainages towards the north, west and south of the volcano. The deposits from these eruptions in the Voipir and Chaillupén River (Villarrica) and the Tepú River (Calbuco) are studied. The 1971 lahar deposits on Villarrica volcano show a great number of internal structures such as lamination, lenses, grading of larger clasts and a great abundance of large floating blocks on top of the deposits. The granulometry can be unimodal or bimodal with less than 5% by weight of silt + clay material. SEM images reveal a great variety of forms and compositions of clasts. The 1961 lahar deposits on Calbuco volcano have a scarce number of internal structures, steeper margins and features of hot emplacement such as semi-carbonized vegetal rests, segregation pipes and a more consolidated matrix. The granulometry usually is bimodal with great quantities of silt + clay material (> 10% by weight). SEM images show a uniformity of composition and forms of clasts. Differences on deposits reveal different dynamics on both lahars. The Villarrica lahar was generated by sudden melt of ice and snow during the paroxysmal phase of the 1971 eruption, when a high fountain of lava was formed. The melted water flowed down on the flanks of the volcano and incorporated sediments to become transition flows, highly energetic and were emplaced incrementally. Dilution of the flows occurs when the lahars reached unconfined and flatter areas. In cases where the lahar flow found large water streams, dilution is enhanced. The Calbuco lahars were generated by the dilution of block and ash pyroclastic flows by flowing over the ice or snow or by entering active rivers

  4. Temporal and spatial distribution of floating objects in coastal waters of central-southern Chile and Patagonian fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, Iván A.; Rivadeneira, Marcelo M.; Thiel, Martin

    2011-03-01

    Floating objects are suggested to be the principal vector for the transport and dispersal of marine invertebrates with direct development as well as catalysts for carbon and nutrient recycling in accumulation areas. The first step in identifying the ecological relevance of floating objects in a specific area is to identify their spatio-temporal distribution. We evaluated the composition, abundance, distribution, and temporal variability of floating objects along the continental coast of central-southern Chile (33-42°S) and the Patagonian fjords (42-50°S) using ship surveys conducted in austral winter (July/August) and spring (November) of the years 2002-2005 and 2008. Potential sources of floating items were identified with the aid of publicly available databases and scientific reports. We found three main types of floating objects, namely floating marine debris (mainly plastic objects and Styrofoam), wood (trunks and branches), and floating kelps ( Macrocystis pyrifera and Durvillaea antarctica). Floating marine debris were abundant along most of the examined transects, with markedly lower abundances toward the southern fjord areas. Floating marine debris abundances generally corresponded to the distribution of human activities, and were highest in the Interior Sea of Chiloé, where aquaculture activities are intense. Floating wood appeared sporadically in the study area, often close to the main rivers. In accordance with seasonal river run-off, wood was more abundant along the continental coast in winter (rainy season) and in the Patagonian fjords during the spring surveys (snow melt). Densities of the two floating kelp species were similar along the continental coast, without a clear seasonal pattern. M. pyrifera densities increased towards the south, peaking in the Patagonian fjords, where it was dominant over D. antarctica. Densities of M. pyrifera in the Patagonian fjords were highest in spring. Correlation analyses between the abundances of floating

  5. Late quaternary vegetation of southern Isla Grande de Chiloñ, Chile

    NASA Astrophysics Data System (ADS)

    Villagran, Carolina

    1988-05-01

    Late-glacial-Holocene forest history of southern Isla Chiloé (latitude 43°10' S) was reconstructed on the basis of pollen analysis in three profiles (Laguna Soledad, Laguna Chaiguata, Puerto Carmen). Prior to 12,500 yr B.P. pollen records are dominated by plant taxa characteristic of open habitats (Zone I). From 12,500 yr B.P. to the present, tree species predominate in the pollen records (Zones II-V). Between 12,500 and 9500 yr B.P. ombrophyllous taxa ( Nothofagus, Podocarpus nubigena. Myrtaceae, Fitzroya/Pilgerodendron, and Drimys) are frequent in all pollen diagrams, suggesting a wetter and colder climate than the present. Between 9000 and 5500 yr B.P. Valdivian forest elements, such as Nothofagus dombeyi type, Weinmannia, and Eucryphia/Caldcluvia, dominate, indicating a period of drier and warmer climate. From 5500 yr B.P. onward, the expansion of mixed North Patagonian-Subantarctic forest elements and the increased frequence of Tepualia suggest increased rainfall and temperatures oscillating around the modern values. The change from open to forest vegetation (ca. 12,500 yr B.P.) probably represents the most pronounced climatic change in the record and can be interpreted as the glacial-postglacial transition in the study area.

  6. Latest Pleistocene and Holocene glacial events in the Colonia valley, Northern Patagonia Icefield, southern Chile

    USGS Publications Warehouse

    Nimick, David A.; Mcgrath, Daniel; Mahan, Shannon; Friesen, Beverly A.; Leidich, Jonathan

    2016-01-01

    The Northern Patagonia Icefield (NPI) is the primary glaciated terrain worldwide at its latitude (46.5–47.5°S), and constraining its glacial history provides unique information for reconstructing Southern Hemisphere paleoclimate. The Colonia Glacier is the largest outlet glacier draining the eastern NPI. Ages were determined using dendrochronology, lichenometry, radiocarbon, cosmogenic 10Be and optically stimulated luminescence. Dated moraines in the Colonia valley defined advances at 13.2 ± 0.95, 11.0 ± 0.47 and 4.96 ± 0.21 ka, with the last being the first constraint on the onset of Neoglaciation for the eastern NPI from a directly dated landform. Dating in the tributary Cachet valley, which contains an ice-dammed lake during periods of Colonia Glacier expansion, defined an advance at ca. 2.95 ± 0.21 ka, periods of advancement at 810 ± 49 cal a BP and 245 ± 13 cal a BP, and retreat during the intervening periods. Recent Colonia Glacier thinning, which began in the late 1800s, opened a lower-elevation outlet channel for Lago Cachet Dos in ca. 1960. Our data provide the most comprehensive set of Latest Pleistocene and Holocene ages for a single NPI outlet glacier and expand previously developed NPI glacial chronologies.

  7. Hurricane Sandy washover deposits on southern Long Beach Island, New Jersey

    USGS Publications Warehouse

    Bishop, James M.; Richmond, Bruce M.; Zaremba, Nicholas J.; Lunghino, Brent D.; Kane, Haunani H.

    2016-07-22

    Sedimentologic and topographic data from Hurricane Sandy washover deposits were collected from southern Long Beach Island, New Jersey, in order to document changes to the barrier-island beaches, dunes, and coastal wetlands caused by Hurricane Sandy and subsequent storm events. These data will provide a baseline dataset for use in future coastal change descriptive and predictive studies and assessments. The data presented here were collected as part of the U.S. Geological Survey’s Barrier Island and Estuarine Wetland Physical Change Assessment Project (http://coastal.er.usgs.gov/sandy-wetland-assessment/), which aims to assess ecological and societal vulnerability that results from long- and short-term physical changes to barrier islands and coastal wetlands. This report describes data that were collected in April 2015, approximately 2½ years after Hurricane Sandy’s landfall on October 29, 2012. During the field campaign, washover deposits were photographed and described, and sediment cores, sediment samples, and surface-elevation data were collected. Data collected during this study, including sample locations and elevations, core photographs, computed tomography scans, descriptive core logs, sediment grain-size data, and accompanying Federal Geographic Data Committee metadata, are available in the associated U.S. Geological Survey data release (Bishop and others, 2016; http://dx.doi.org/10.5066/F7PK0D7S).

  8. Lithospheric flexure revealed by Pleistocene emerged marine terraces on the southern Hawaiian Islands

    SciTech Connect

    Jones, A.T. . Dept. of Oceanography)

    1992-01-01

    New field and geochronological data from emerged marine deposits in the southern Hawaiian Islands suggest uplift of the islands of Molokai, Lanai and Oahu. Corals from these islands were dated by ESR. The accumulated dose for aragonitic coral at ESR signal, g = 2.0007, was determined by the additive dose method. The environmental dose rate was estimated from the Uranium concentration in corals and by using an estimate of 2.5 rad/a for the cosmic ray dose. The ESR ages of the highest terraces on Molokai are 290 [+-] 31 ka (30 m), on Lanai 217 [+-] 19 ka (50 m) and on Oahu 468 [+-] 36 ka (28 m). The age and elevation of the marine terraces are interpreted to imply uplift during the Late Quaternary. Lithospheric flexure combined with horizontal plate motion is proposed as a mechanism to describe the pattern of uplifted terraces on these islands. Using two-dimensional elastic plate models, the height of maximum bulge is approximately 4% to 7% of the maximum deflection for a continuous or broken plate model. Drowned reefs off Hawaii indicate subsidence of 1 km since 340 ka. Thus, the magnitude of observed uplift (30--50 m) is consistent with theoretical maximum bulge heights derived from numerical results.

  9. A large localized outbreak of Mycobacterium ulcerans infection on a temperate southern Australian island.

    PubMed

    Veitch, M G; Johnson, P D; Flood, P E; Leslie, D E; Street, A C; Hayman, J A

    1997-12-01

    Mycobacterium ulcerans, the organism which causes Buruli or Bairnsdale ulcer, has never been isolated in culture from an environmental sample. Most foci of infection are in tropical regions. The authors describe the first 29 cases of M. ulcerans infection from a new focus on an island in temperate southern Australia, 1992-5. Cases were mostly elderly, had predominantly distal limb lesions and were clustered in a small region in the eastern half of the main town on the island. The authors suspected that an irrigation system which lay in the midst of the cluster was a source of infection. Limitation of irrigation was associated with a dramatic reduction in the number of new cases. These findings support the hypothesis that M. ulcerans has an aquatic reservoir and that persons may be infected directly or indirectly by mycobacteria disseminated locally by spray irrigation.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Patterns in floral traits and plant breeding systems on Southern Ocean Islands

    PubMed Central

    Lord, Janice M.

    2015-01-01

    The harsh climatic conditions and paucity of potential pollinators on Southern Ocean Islands (SOIs; latitude 46°S–55°S) lead to the expectation that anemophily or self-fertilization are the dominant modes of plant sexual reproduction. However, at least some species have showy inflorescences suggesting biotic pollination or dimorphic breeding systems necessitating cross-pollination. This study investigates whether anemophily and self-compatibility are common on SOIs, whether species or genera with these traits are more widespread or frequent at higher latitudes, and whether gender dimorphy is correlated with anemophily, as might occur if reliance on pollinators was a disadvantage. Of the 321 flowering plant species in the SOI region, 34.3 % possessed floral traits consistent with anemophily. Compatibility information was located for 94 potentially self-fertilizing species, of which 92.6 % were recorded as partially or fully self-compatible. Dioecy occurred in 7.1 % of species overall and up to 10.2 % of island floras, but has not clearly arisen in situ. Gynodioecy occurred in 3.4 % of species. The frequency of anemophily and gender dimorphy did not differ between the SOI flora and southern hemisphere temperate reference floras. At the species level, gender dimorphy was positively associated with fleshy fruit, but at the genus level it was associated with occurrence in New Zealand and a reduced regional distribution. Anemophily was more prevalent in genera occurring on subantarctic islands and the proportion of species with floral traits suggestive of biotic pollination was significantly higher on climatically milder, cool temperate islands. These results support the contention that reliance on biotic pollinators has constrained the distribution of species on SOIs; however, it is also clear that the reproductive biology of few SOI species has been studied in situ and many species likely employ a mixed mating strategy combining biotic pollination with self

  12. Seasonal Changes in Soil Moisture Content in Northern Chile and Southern California Inferred from SAR data

    NASA Astrophysics Data System (ADS)

    Scott, C. P.; Lohman, R. B.

    2015-12-01

    InSAR-based studies of the seismic cycle have focused primarily on the interferometric phase observations, which place constraints on the amount of uplift or subsidence of the ground surface. Recently, coseismic InSAR coherence has also been used to rapidly identify urban damage, surface ruptures, cracking, and soil liquefaction. Here we demonstrate that time-variable correlation and amplitude data contain additional information about surficial processes and material properties that may affect ground deformation and seismic hazard. In the use of correlation for hazard response, distinguishing the coseismic signal from other changes in surface properties associated with variations in soil moisture content, vegetation and snow cover, and wind is critical. Building SAR-based catalogues of ground properties will therefore improve the reliability of rapid response and aid in the designing of future SAR missions to better map surface ruptures, off-fault deformation, and coseismic damage. In this project, we characterize the seasonal variations in the soil moisture content in the Northern Chilean Coastal Cordillera and Southern California. The extreme climate of the Atacama Desert characterized by hyperaridity and coastal fog during the non-summer months creates an ideal landscape for exploring surface properties. We produce interferograms using L-band ALOS data (λ = 23.6 cm) that span 46 days to three years and have perpendicular baselines less than 1500 m. We observe a strong seasonal dependence on correlation that extends to the maximum elevation of the fog penetration. Interferograms with only austral summer acquisitions are more correlated than interferograms with one or both acquisitions in the autumn, winter or spring, even when the summer interferograms span multiple years. We propose that the seasonal dependence is due to small changes in the radar path length caused by variable soil moisture content in the very shallow subsurface. We further consider local

  13. The Late Quaternary peat, vegetation and climate history of the Southern Oceanic Islands of New Zealand

    NASA Astrophysics Data System (ADS)

    McGlone, M. S.

    2002-02-01

    Seven oceanic island groups (Chatham, Bounty, Snares, Antipodes, Auckland, Campbell and Macquarie) lie to the south and east of the southern New Zealand mainland between the Subtropical Convergence and the Antarctic Convergence. They are highly oceanic, experiencing moist, cool, cloudy and windy climates. Deep peat soils cover most of the islands, except for steep slopes and exposed high altitude sites. The three large island groups (Chatham, Auckland and Campbell) support forest and tall scrub in the lowlands, in the latter two grading with altitude through shrubland and grassland to upland tundra. Macrophyllous forbs create luxuriant herbfields in nutrient-rich coastal sites and also, as stunted forms, dominate upland tundra associations. The southernmost island, Macquarie has no woody species, and is covered with tussock grassland, herbfield and tundra. Vegetation cover is highly sensitive to soil saturation and exposure to the strong westerly winds of this region. Extensive oligotrophic bogs occur where drainage is poor and exposure high, and forest and tall scrub are abundant only in sheltered, well-drained lowland sites. Glacial cirque levels indicate mean annual temperatures fell by 5-6°C during the Last Glacial Maximum. A depression of 6-10°C in sea surface temperatures is suggested by deep-sea core analyses, but this seems incompatible with terrestrial evidence. Auckland and Campbell Islands were extensively glaciated, and grassland, herbfield and tundra landscapes prevailed. Glaciers retreated by 15,000 yr BP, and landscapes had stabilised and peat soils begun forming by 12,000 yr BP. By the beginning of the Holocene, oligotrophic bog, grassland and shrubland were dominant. Scrub and low forest spread slowly during the early Holocene in the Chatham, Auckland and Campbell Islands, inhibited by cloudy, moist climates, low insolation and wet soils. Maximum extent of forest and scrub occurred between 6000 and 2000 yr BP, most probably linked with a drying

  14. The 2008 eruption of Chaitén volcano, Southern Chile: a tectonically controlled eruption?

    NASA Astrophysics Data System (ADS)

    Lara, L. E.; Pallister, J. S.; Ewert, J. W.

    2008-12-01

    initially high plumes and only limited column collapse argue for a relatively strong and narrow conduit and vent structure during the early explosive eruptions. However, the sustained high-rate and large-volume lava eruption (now 4 months in duration) accompanied by relatively low explosivity and low SO2 emissions argue against a purely gas-driven eruptive process. We propose a model for magmatism at Chaitén, in which the timing and compositions of eruptions are controlled by tectonism along the Liquiñe-Ofqui Fault Zone (LOFZ), a 1200 km long structure that is part of a dextral transpressional arc domain. In this model, silicic magmas are trapped and stored at deep levels of the crust (10 km?) during periods of upper crustal localized compression, and eruptions are triggered by tectonic shifts that open tear faults and promote magma transport to the surface. Consistent with seismicity along the LOFZ and subsidiary branches before and during the eruption and with new InSAR data that indicate fault-controlled syn-eruptive deformation, we suggest that such a process triggered the 2008 eruption and that re-establishment of compression, following the initial Plinian phase, has sustained an anomalously high-rate of lava production for the past four months. In turn, fluid flow along the fault-fracture network enhances seismic activity, which is still recorded. The two- way coupling between tectonics and volcanism provides a challenging conceptual framework for hazards assessment in Southern Andes.

  15. Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence.

    PubMed

    Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita

    2015-01-01

    In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy.

  16. A cross sectional observational study to estimate herd level risk factors for Leptospira spp. serovars in small holder dairy cattle farms in southern Chile

    PubMed Central

    2014-01-01

    Background The south of Chile constitutes the main cattle milk producing area of the country. Regarding leptospirosis control in Chile, there is neither an official program nor an epidemiological characterization of smallholder dairy farms. This study was carried out to determine Leptospira seroprevalence and to evaluate risk factors associated with seropositivity at herd level in smallholder bovine dairy herds in southern Chile. A cross-sectional study was conducted, and a convenient sample of 1,537 apparently healthy dairy cows was included in the study. Individual blood samples were taken and examined for six selected reference Leptospira serovars by the Microscopic Agglutination Test (MAT). Results Of the included herds 75% (52/69) showed serological titers against one or more Leptospira serovar. Leptospira borgpetersenii serovar Hardjo was the serovar most frequently (81%) reported from animals with positive results. The variables considered risk factors for Leptospira seropositivity were calve natural breeding system, using a specific calving area and vaccination against Leptospira. Adult cows in contact with calves weaned, proved to be a protective factor against infection. Conclusions Herds neglecting the management practices mentioned in this study could represent an important source of Leptospira infection for other herds in the same geographic area, as well as for other animal species. PMID:24906684

  17. Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence

    PubMed Central

    Colihueque, Nelson; Gantz, Alberto; Rau, Jaime Ricardo; Parraguez, Margarita

    2015-01-01

    Abstract In this paper new mitochondrial COI sequences of Common Barn Owl Tyto alba (Scopoli, 1769) and Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile are reported and compared with sequences from other parts of the World. The intraspecific genetic divergence (mean p-distance) was 4.6 to 5.5% for the Common Barn Owl in comparison with specimens from northern Europe and Australasia and 3.1% for the Short-eared Owl with respect to samples from north America, northern Europe and northern Asia. Phylogenetic analyses revealed three distinctive groups for the Common Barn Owl: (i) South America (Chile and Argentina) plus Central and North America, (ii) northern Europe and (iii) Australasia, and two distinctive groups for the Short-eared Owl: (i) South America (Chile and Argentina) and (ii) north America plus northern Europe and northern Asia. The level of genetic divergence observed in both species exceeds the upper limit of intraspecific comparisons reported previously for Strigiformes. Therefore, this suggests that further research is needed to assess the taxonomic status, particularly for the Chilean populations that, to date, have been identified as belonging to these species through traditional taxonomy. PMID:26668551

  18. A cross sectional observational study to estimate herd level risk factors for Leptospira spp. serovars in small holder dairy cattle farms in southern Chile.

    PubMed

    Salgado, Miguel; Otto, Barbara; Sandoval, Errol; Reinhardt, German; Boqvist, Sofia

    2014-06-06

    The south of Chile constitutes the main cattle milk producing area of the country. Regarding leptospirosis control in Chile, there is neither an official program nor an epidemiological characterization of smallholder dairy farms. This study was carried out to determine Leptospira seroprevalence and to evaluate risk factors associated with seropositivity at herd level in smallholder bovine dairy herds in southern Chile.A cross-sectional study was conducted, and a convenient sample of 1,537 apparently healthy dairy cows was included in the study. Individual blood samples were taken and examined for six selected reference Leptospira serovars by the Microscopic Agglutination Test (MAT). Of the included herds 75% (52/69) showed serological titers against one or more Leptospira serovar. Leptospira borgpetersenii serovar Hardjo was the serovar most frequently (81%) reported from animals with positive results. The variables considered risk factors for Leptospira seropositivity were calve natural breeding system, using a specific calving area and vaccination against Leptospira. Adult cows in contact with calves weaned, proved to be a protective factor against infection. Herds neglecting the management practices mentioned in this study could represent an important source of Leptospira infection for other herds in the same geographic area, as well as for other animal species.

  19. A Multiproxy Reconstruction of Holocene Southern Westerlies from the Auckland Islands

    NASA Astrophysics Data System (ADS)

    Nichols, J. E.; Moy, C. M.; Peteet, D. M.; Weiss, A.; Curtin, L. G.

    2015-12-01

    The strength and position of the Southern Hemisphere Westerly Wind belt plays an important role in our understanding of the global carbon cycle and glacial-interglacial climate change. We present a paleoclimate record that is primarily influenced by the strength and latitudinal position of the Southern Hemisphere Westerly Winds from a late Holocene lake sediment core and a peat core that spans the last 13,000 years, both obtained from New Zealand's subantarctic Auckland Islands (50°S, 166°E). Several proxy indicators contribute to our reconstruction. Hydrogen isotope ratios of specific organic molecules allow us to reconstruct the hydrogen isotope ratios of precipitation. Using macrofossil counts and the abundances of leaf wax biomarkers, we are able to estimate the moisture balance at our sites. Model simulations of the Westerlies and the rate and isotope ratios of precipitation allow us to interpret our proxy data as changes in the strength and position of the Westerly Winds. In our lacustrine sediment, we found that the Westerlies have been shifting southward since the Little Ice Age, consistent with modern observations of a southward shift. In the peatland sediment, we found a multi-millennial northward shift in the Westerlies during the middle Holocene. We will present further ongoing work that strengthens the chronology of Auckland Islands environmental change and integrates these results with vegetation shifts identified in pollen and macrofossil data.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  1. Tectonic control on rock uplift, exhumation, and topography above an oceanic ridge collision: Southern Patagonian Andes (47°S), Chile

    NASA Astrophysics Data System (ADS)

    Georgieva, Viktoria; Melnick, Daniel; Schildgen, Taylor F.; Ehlers, Todd A.; Lagabrielle, Yves; Enkelmann, Eva; Strecker, Manfred R.

    2016-06-01

    The subduction of bathymetric anomalies at convergent margins can profoundly affect subduction dynamics, magmatism, and the structural and geomorphic evolution of the overriding plate. The Northern Patagonian Icefield (NPI) is located east of the Chile Triple Junction at ~47°S, where the Chile Rise spreading center collides with South America. This region is characterized by an abrupt increase in summit elevations and relief that has been controversially debated in the context of geodynamic versus glacial erosion effects on topography. Here we present geomorphic, thermochronological, and structural data that document neotectonic activity along hitherto unrecognized faults along the flanks of the NPI. New apatite (U-Th)/He bedrock cooling ages suggest faulting since 2-3 Ma. We infer the northward translation of an ~140 km long fore-arc sliver -- the NPI block -- results from enhanced partitioning of oblique plate convergence due to the closely spaced collision of three successive segments of the Chile Rise. In this model, greater uplift occurs in the hanging wall of the Exploradores thrust at the northern leading edge of the NPI block, whereas the Cachet and Liquiñe-Ofqui dextral faults decouple the NPI block along its eastern and western flanks, respectively. Localized extension possibly occurs at its southern trailing edge along normal faults associated with margin-parallel extension, tectonic subsidence, and lower elevations along the Andean crest line. Our neotectonic model provides a novel explanation for the abrupt topographic variations inland of the Chile Triple Junction and emphasizes the fundamental effects of local tectonics on exhumation and topographic patterns in this glaciated landscape.

  2. Water input and water release from the subducting Nazca Plate along southern Central Chile (33°S-46°S)

    NASA Astrophysics Data System (ADS)

    Völker, David; Stipp, Michael

    2015-06-01

    The age of the subducting Nazca Plate off Chile increases northward from 0 Ma at the Chile Triple Junction (46°S) to 37 Ma at the latitude of Valparaíso (32°S). Age-related variations in the thermal state of the subducting plate impact on (a) the water influx to the subduction zone, as well as on (b) the volumes of water that are released under the continental fore arc or, alternatively, carried beyond the arc. Southern Central Chile is an ideal setting to study this effect, because other factors for the subduction zone water budget appear constant. We determine the water influx by calculating the crustal water uptake and by modeling the upper mantle serpentinization at the outer rise of the Chile Trench. The water release under fore arc and arc is determined by coupling FEM thermal models of the subducting plate with stability fields of water-releasing mineral reactions for upper and lower crust and hydrated mantle. Results show that both the influx of water stored in, and the outflux of water released from upper crust, lower crust, and mantle vary drastically over segment boundaries. In particular, the oldest and coldest segments carry roughly twice as much water into the subduction zone as the youngest and hottest segments, but their release flux to the fore arc is only about one fourth of the latter. This high variability over a subduction zone of <1500 km length shows that it is insufficient to consider subduction zones as uniform entities in global estimates of subduction zone fluxes.

  3. Variations in the quantity and composition of seston from an estuary in southern Chile on different temporal scales

    NASA Astrophysics Data System (ADS)

    Chaparro, O. R.; Segura, C. J.; Montiel, Y. A.; Thompson, R. J.; Navarro, J. M.

    2008-03-01

    Estuaries are characterised by highly variable environmental conditions largely driven by tidal and atmospheric forces. This study investigates variation in the physical environment and the composition of the seston on various temporal scales in the Quempillén estuary, southern Chile. The water column was sampled throughout the tidal cycle at various times of the year. Total particulate matter, particulate inorganic matter, particulate organic matter, particle numbers, total particle volume, proximate biochemical composition and energy content of the seston, chlorophyll a and chloropigments were routinely measured. In each of the months in which sampling took place, two or three tidal cycles were examined. The information not only helps to explain the dynamics of the estuary, but is essential for an understanding of the physiology and ecology of the suspension-feeders which exploit the seston as a food source, the most dominant being the gastropod Crepipatella dilatata. Temperature and salinity were generally highest during summer, but seston quality, defined by energy content and biochemical composition (lipid, protein and carbohydrate) was higher at the end of winter and during spring. Chlorophyll a values were greatest in late spring (November). Many of the variables studied changed frequently according to the phase of the tidal cycle, and in several cases significant differences were observed among tidal cycles from the same month of the same year. In general the variables measured did not exhibit consistent patterns linked to the tidal cycle, possibly because any such patterns were masked by atmospheric conditions (wind and rain) that dominate the region and greatly influence the estuary. The quantity and quality of the seston available to suspension-feeders is largely determined by these atmospheric forces, which cause an influx of terrigenous material from adjacent areas and also resuspend bottom sediment. These effects are magnified by the shallowness of

  4. Forearc deformation processes inferred from drowned shorelines in the Arauco Bay, Southern Chile (37°S)

    NASA Astrophysics Data System (ADS)

    Jara-Muñoz, Julius; Melnick, Daniel; Bernhardt, Anne; Argandoña, Boris; Gonzalez-Acuña, Javiera; Strecker, Manfred

    2015-04-01

    Relict drowned landscapes often constitute preserved snapshots of terrestrial environments prior to flooding episodes during the Quaternary. Forearc deformation processes are usually recorded by coastal landforms, such as paleo-shorelines or marine terraces reflecting pronounced vertical movements. Similarly, drowned coastal landscapes represent past sea-level positions that can be used as tracers of tectonic deformation and sea-level change. In this study we present hitherto unrecognized drowned Quaternary shorelines in the Arauco Bay of southern Chile. The Arauco Bay lies inland of the Santa Maria Fault and is surrounded by densely populated areas, many devastated by the tsunami following the 2010 M 8.8 Maule earthquake. The shorelines are folded, apparently as a result of slip along the Santa Maria Fault, a blind splay-fault system rooted in the Nazca-South America plate-boundary zone, documenting protracted tectonic activity. We mapped and used these drowned geomorphic markers using high-resolution bathymetry (2.5 m) to infer rates and style of deformation along the Santa Maria splay fault. For this purpose we used surface classification models, observations from a remotely operated vehicle (ROV), and sedimentology of sea-bottom samples. High roughness areas correspond to well-exposed bedrock outcrops. The enclosed patches were studied in detail and compared with LiDAR data from emerged and actively forming marine platforms from nearby areas. Three levels of drowned shorelines were identified: at ~110 m, ~40 and ~60 m depth, respectively. The shallower two shorelines are distributed as fringes parallel to the coastline of the Arauco Bay and deepen towards the trench. We selected the shallowest level as an exploratory target for a ROV dive obtaining video and still images of micromorphologic features; a sampling target was selected at 45 m where professional divers collected samples of bedrock and sediments. Chronologic correlation was performed based on global

  5. Coral reef origins of atmospheric dimethylsulfide at Heron Island, southern Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Swan, Hilton B.; Jones, Graham B.; Deschaseaux, Elisabeth S. M.; Eyre, Bradley D.

    2017-01-01

    Atmospheric dimethylsulfide (DMSa), continually derived from the world's oceans, is a feed gas for the tropospheric production of new sulfate particles, leading to cloud condensation nuclei that influence the formation and properties of marine clouds and ultimately the Earth's radiation budget. Previous studies on the Great Barrier Reef (GBR), Australia, have indicated coral reefs are significant sessile sources of DMSa capable of enhancing the tropospheric DMSa burden mainly derived from phytoplankton in the surface ocean; however, specific environmental evidence of coral reef DMS emissions and their characteristics is lacking. By using on-site automated continuous analysis of DMSa and meteorological parameters at Heron Island in the southern GBR, we show that the coral reef was the source of occasional spikes of DMSa identified above the oceanic DMSa background signal. In most instances, these DMSa spikes were detected at low tide under low wind speeds, indicating they originated from the lagoonal platform reef surrounding the island, although evidence of longer-range transport of DMSa from a 70 km stretch of coral reefs in the southern GBR was also observed. The most intense DMSa spike occurred in the winter dry season at low tide when convective precipitation fell onto the aerially exposed platform reef. This co-occurrence of events appeared to biologically shock the coral resulting in a seasonally aberrant extreme DMSa spike concentration of 45.9 nmol m-3 (1122 ppt). Seasonal DMS emission fluxes for the 2012 wet season and 2013 dry season campaigns at Heron Island were 5.0 and 1.4 µmol m-2 day-1, respectively, of which the coral reef was estimated to contribute 4 % during the wet season and 14 % during the dry season to the dominant oceanic flux.

  6. Herd-level prevalence of Map infection in dairy herds of southern Chile determined by culture of environmental fecal samples and bulk-tank milk qPCR.

    PubMed

    Kruze, J; Monti, G; Schulze, F; Mella, A; Leiva, S

    2013-09-01

    Paratuberculosis, an infectious disease of domestic and wild ruminants caused by Mycobacterium avium subsp. paratuberculosis (Map), is an economically important disease in dairy herds worldwide. In Chile the disease has been reported in domestic and wildlife animals. However, accurate and updated estimations of the herd-prevalence in cattle at national or regional level are not available. The objectives of this study were to determine the herd-level prevalence of dairy herds with Map infected animals of Southern Chile, based on two diagnostic tests: culture of environmental fecal samples and bulk-tank milk qPCR. Two composite environmental fecal samples and one bulk-tank milk sample were collected during September 2010 and September 2011 from 150 dairy farms in Southern Chile. Isolation of Map from environmental fecal samples was done by culture of decontaminated samples on a commercial Herrold's Egg Yolk Medium (HEYM) with and without mycobactin J. Suspicious colonies were confirmed to be Map by conventional IS900 PCR. Map detection in bulk-tank milk samples was done by real time IS900 PCR assay. PCR-confirmed Map was isolated from 58 (19.3%) of 300 environmental fecal samples. Holding pens and manure storage lagoons were the two more frequent sites found positive for Map, representing 35% and 33% of total positive samples, respectively. However, parlor exits and cow alleyways were the two sites with the highest proportion of positive samples (40% and 32%, respectively). Herd prevalence based on environmental fecal culture was 27% (true prevalence 44%) compared to 49% (true prevalence 87%) based on bulk-tank milk real time IS900 PC. In both cases herd prevalence was higher in large herds (>200 cows). These results confirm that Map infection is wide spread in dairy herds in Southern Chile with a rough herd-level prevalence of 28-100% depending on the herd size, and that IS900 PCR on bulk-tank milk samples is more sensitive than environmental fecal culture to detect

  7. A study of the relationship between degree of ethnocentrism and typologies of food purchase in supermarkets in central-southern Chile.

    PubMed

    Schnettler, Berta; Miranda, Horacio; Lobos, Germán; Sepúlveda, José; Denegri, Marianela

    2011-06-01

    The objective of this study was to distinguish different types of consumers according to their level of ethnocentrism in relation to the consumption of foodstuffs in central-southern Chile. To do this a modification of the CETSCALE (Consumer Ethnocentric Tendencies Scale) was applied through direct survey of 800 habitual supermarket shoppers in two cities in central-southern Chile. The modified CETSCALE presented a sufficient level of internal consistency and there were three factors which included the 17 items of the scale. Five typologies of consumer with different degrees of ethnocentrism were distinguished by cluster analysis, based on the values of the factors and items in the CETSCALE. The composition of the typologies of consumers were related to the city and zone of residence, age, socioeconomic level, self-declared life-style, ethnic origin, knowledge of the origin of the foodstuffs purchased, frequency of purchase of imported foodstuffs and reasons for rejection in the case of a low purchase frequency. It may therefore be concluded that different levels of ethnocentrism exist in the consumption of foodstuffs, related with some socio-demographic characteristics of consumers and their attitudes to imported foodstuffs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Residues of persistent organochlorine contaminants in southern elephant seals (Mirounga leonina) from Elephant Island, Antarctica.

    PubMed

    Miranda-Filho, Kleber C; Metcalfe, Tracy L; Metcalfe, Chris D; Robaldo, Ricardo B; Muelbert, Mônica M C; Colares, Elton P; Martinez, Pablo E; Bianchini, Adalto

    2007-06-01

    Contamination of blubber tissues by organochlorine pesticides (OC) and PCBs was assessed in female and male pups and juveniles, as well as in adult females and subdominant adult males of the Southern elephant seal, Mirounga leonina, from Elephant Island in the Antarctic Peninsula. All residues of persistent organochlorine contaminants analyzed were found in blubber samples, except for beta-HCH, endosulfan II, endrin, heptachlor, and aldrin. The relative concentrations of the analytes detected were sigmaDDT > sigmaPCB > sigmachlordane > mirex > dieldrin > HCB> sigmaendosulfan > methoxychlor > sigmaHCHs > other OC pesticides. OC and PCBs concentrations were 1 or 2 orders of magnitude lower than those found in pinnipeds from northern hemisphere. The ratio sigmaDDT/sigmaPCB was higher in southern elephant seals. The relative importance of some OC residues indicates that pesticides used either currently or in the recent past in countries in the southern hemisphere are the sources of contamination in the Antarctic region. Data showed that concentrations of contaminants generally increased from pups < juveniles < adults and suggested that pups accumulated contaminants through transfer from the mother seals via transplacental and lactational routes.

  9. Hepatitis B Among Pacific Islanders in Southern California: How is Health Information Associated with Screening and Vaccination?

    PubMed Central

    Kim, Anna J.; Sablan-Santos, Lola; Quitugua, Lourdes Flores; Aromin, Jay; Lepule, Jonathan; Maguadog, Tony; Perez, Rose; Young, Louise; Young, Steve

    2010-01-01

    We measured Hepatitis B virus (HBV) transmission knowledge and self-reported screening/testing behavior among Pacific Islanders (Guamanians/Chamorros, Samoans, and Tongans) in Southern California. We also examined access and trust by Pacific Islanders of varying health information sources. We administered and analyzed survey data (N = 297), using a convenience sample in Los Angeles, Orange, and San Diego Counties in spring 2009. We found that while Pacific Islander respondents reported that they receive health information from physicians, and largely trust this source, information from and trust in physicians were not statistically significant in explaining whether respondents sought HBV screening or vaccination. PMID:20556491

  10. Kerguelen Islands

    NASA Image and Video Library

    2014-05-27

    This image from NASA Terra spacecraft shows the Kerguelen Islands also known as the Desolation Islands, which are part of the French Southern and Antarctic lands. The islands are among the most isolated places on Earth.

  11. Udonella australis n. sp. (Monogenea), an epibiont on sea-lice from native fish off southern Chile.

    PubMed

    Carvajal, Juan; Sepúlveda, Fabiola

    2002-05-01

    Udonella australis n. sp., an epibiont monogenean living on caligid copepods that infest a native fish, Eleginops maclovinus (Valenciennes), off Chile, South America is described. The species can be separated from other species by its difference in size, especially body size, and the distribution of cephalic glands, vitelline follicles and genital organs. Egg-size is intermediate in comparison with that of other species. The posterior attachment mechanism consists of few muscle fibres and clumped cement-producing glands. All previous descriptions of Udonella caligorum Johnston, 1835 from off Chile correspond to this new species.

  12. HIV Testing Behavior among Pacific Islanders in Southern California: Exploring the Importance of Race/Ethnicity, Knowledge, and Domestic Violence

    ERIC Educational Resources Information Center

    Takahashi, Lois M.; Kim, Anna J.; Sablan-Santos, Lola; Quitugua, Lourdes Flores; Lepule, Jonathan; Maguadog, Tony; Perez, Rose; Young, Steve; Young, Louise

    2011-01-01

    This article presents an analysis of a 2008 community needs assessment survey of a convenience sample of 179 Pacific Islander respondents in southern California; the needs assessment focused on HIV knowledge, HIV testing behavior, and experience with intimate partner/relationship violence. Multivariate logistic regression results indicated that…

  13. The Forests of Southern New England, 2007: A report on the forest resources of Connecticut, Massachusetts, and Rhode Island

    Treesearch

    Brett J. Butler; Charles J. Barnett; Susan J. Crocker; Grant M. Domke; Dale Gormanson; William N. Hill; Cassandra M. Kurtz; Tonya Lister; Christopher Martin; Patrick D. Miles; Randall Morin; W. Keith Moser; Mark D. Nelson; Barbara O' Connell; Bruce Payton; Charles H. Perry; Ronald J. Piva; Rachel Riemann; Christopher W. Woodall

    2011-01-01

    This report summarizes the results of the fifth forest inventory of the forests of Southern New England, defined as Connecticut, Massachusetts, and Rhode Island, conducted by the U.S. Forest Service, Forest Inventory and analysis program. Information on forest attributes, ownership, land use change, carbon, timber products, forest health, and statistics and quality...

  14. Fire history and moisture influences on historical forest age structure in the sky islands of southern Arizona, USA

    Treesearch

    Jose M. Iniguez; Thomas W. Swetnam; Christopher H. Baisan

    2016-01-01

    Aim: The purpose of this study was to examine the influence of moisture and fire on historical ponderosa pine (Pinus ponderosa Dougl. ex Laws.) age structure patterns. Location: We used a natural experiment created over time by the unique desert island geography of southern Arizona. Methods: We sampled tree establishment dates in two sites on Rincon Peak and...

  15. HIV Testing Behavior among Pacific Islanders in Southern California: Exploring the Importance of Race/Ethnicity, Knowledge, and Domestic Violence

    ERIC Educational Resources Information Center

    Takahashi, Lois M.; Kim, Anna J.; Sablan-Santos, Lola; Quitugua, Lourdes Flores; Lepule, Jonathan; Maguadog, Tony; Perez, Rose; Young, Steve; Young, Louise

    2011-01-01

    This article presents an analysis of a 2008 community needs assessment survey of a convenience sample of 179 Pacific Islander respondents in southern California; the needs assessment focused on HIV knowledge, HIV testing behavior, and experience with intimate partner/relationship violence. Multivariate logistic regression results indicated that…

  16. Two new species of the Liolaemuselongatus-kriegi complex (Iguania, Liolaemidae) from Andean highlands of southern Chile.

    PubMed

    Troncoso-Palacios, Jaime; Díaz, Hugo A; Esquerré, Damien; Urra, Felix A

    2015-01-01

    The elongatus-kriegi complex is one of the most diverse clades of the Liolaemus (sensu stricto) subgenus of lizards. There are currently 29 species recognized in this group distributed between Chile and Argentina. Based on molecular evidence, there seem to be five main clades nested within this complex: the elongatus, leopardinus, kriegi, petrophilus and punmahuida clades. Liolaemusbuergeri and Liolaemuskriegi, both of the kriegi clade, were believed to inhabit the surroundings of the Laja Lagoon, in the Biobío Region of Chile. Moreover, this Chilean population of Liolaemuskriegi was recently recognized as an undescribed taxon called "Liolaemus sp. A" based on molecular phylogenetics. In this work, we studied these two populations of the Laja Lagoon and provided the morphological diagnosis to describe them as two new species: Liolaemusscorialis sp. n. and Liolaemuszabalai sp. n., previously considered Liolaemusbuergeri and "Liolaemuskriegi/Liolaemus sp. A" respectively. Additionally, we identified another population of Liolaemusscorialis in the vicinity of La Mula Lagoon in the Araucanía Region of Chile. Liolaemusscorialis differs from almost all of the species of the elongatus-kriegi complex by its considerably smaller size. Nevertheless, without molecular data we cannot assign it to any particular subclade. Liolaemuszabalai belongs to the kriegi clade based on published molecular phylogenies. Finally, we provide some natural history data on both species and we document for the first time the presence of Liolaemusneuquensis in Chile from a museum specimen from La Mula Lagoon.

  17. Genome-wide SNP analysis reveals population structure and demographic history of the ryukyu islanders in the southern part of the Japanese archipelago.

    PubMed

    Sato, Takehiro; Nakagome, Shigeki; Watanabe, Chiaki; Yamaguchi, Kyoko; Kawaguchi, Akira; Koganebuchi, Kae; Haneji, Kuniaki; Yamaguchi, Tetsutaro; Hanihara, Tsunehiko; Yamamoto, Ken; Ishida, Hajime; Mano, Shuhei; Kimura, Ryosuke; Oota, Hiroki

    2014-11-01

    The Ryukyu Islands are located to the southwest of the Japanese archipelago. Archaeological evidence has revealed the existence of prehistoric cultural differentiation between the northern Ryukyu islands of Amami and Okinawa, and the southern Ryukyu islands of Miyako and Yaeyama. To examine a genetic subdivision in the Ryukyu Islands, we conducted genome-wide single nucleotide polymorphism typing of inhabitants from the Okinawa Islands, the Miyako Islands, and the Yaeyama Islands. Principal component and cluster analyses revealed genetic differentiation among the island groups, especially between Okinawa and Miyako. No genetic affinity was observed between aboriginal Taiwanese and any of the Ryukyu populations. The genetic differentiation observed between the inhabitants of the Okinawa Islands and the Miyako Islands is likely to have arisen due to genetic drift rather than admixture with people from neighboring regions. Based on the observed genetic differences, the divergence time between the inhabitants of Okinawa and Miyako islands was dated to the Holocene. These findings suggest that the Pleistocene inhabitants, whose bones have been found on the southern Ryukyu Islands, did not make a major genetic contribution, if any, to the present-day inhabitants of the southern Ryukyu Islands.

  18. The Cottage Lake Aeromagnetic Lineament: A Possible Onshore Extension of the Southern Whidbey Island Fault, Washington

    USGS Publications Warehouse

    Blakely, Richard J.; Sherrod, Brian L.; Wells, Ray E.; Weaver, Craig S.; McCormack, David H.; Troost, Kathy G.; Haugerud, Ralph A.

    2004-01-01

    The northwest-striking southern Whidbey Island fault zone (SWIF) was mapped previously using borehole data and potential-field anomalies on Whidbey Island and marine seismic surveys beneath surrounding waterways. Abrupt subsidence at a coastal marsh on south-central Whidbey Island suggests that the SWIF experienced a MW 6.5 to 7.0 earthquake about 3000 years ago. Southeast of Whidbey Island, a hypothesized southeastward projection of the SWIF would make landfall between the cities of Seattle and Everett. As part of systematic, ongoing studies by the U.S. Geological Survey, University of Washington, and other earth science organizations to evaluate potentially active faults and other earth hazards throughout the Puget Lowland, we test this hypothesis using aeromagnetic, lidar, and borehole data. Linear, northwest-striking magnetic anomalies traversing the mainland region project southeastward toward the communities of Woodinville and Maltby, Washington. All of these magnetic anomalies are low in amplitude and best illuminated in residual magnetic fields. The most prominent of the residual magnetic anomalies extends at least 16 km, lies approximately on strike with the SWIF on Whidbey Island, and passes near Crystal and Cottage Lakes, about 27 km southeast of downtown Everett. In places, this magnetic anomaly is associated with topographic lineaments, but spectral analysis indicates that the source of the anomaly extends to depths greater than 2 km and cannot be explained entirely by topographic effects. The Alderwood #1 oil exploration well located on strike with the Cottage Lake aeromagnetic lineament shows evidence of deformation over a total depth range of 3000 m; some beds within this interval exhibit intense fracturing and shearing, although deformation within the well can only be constrained as post-early Oligocene and pre-Pleistocene. Boreholes acquired as part of a wastewater tunnel project show evidence of soil disturbance at locations where some

  19. Evidence for late Holocene relative sea-level fall from reconnaissance stratigraphical studies in an area of earthquake-subsided intertidal deposits, Isla Chiloé, southern Chile

    USGS Publications Warehouse

    Frostick, L.E.; Steel, R.J.; Bartsch-Winkler, S.; Schmoll, H.R.

    1993-01-01

    At Río Pudeto and Quetalmahue, two estuaries along the northern shore of Isla Chiloé that subsided as much as 2 m in the great 1960 earthquake, reconnaissance stratigraphical studies reveal evidence of a regressive, nearshore marine sequence. The intertidal deposits include a peat-bearing, high-intertidal marsh sequence as thick as 1.4 m overlying shell- and foraminifera-bearing silt and clay layers presumed to represent a deeper water, low-intertidal environment.Stratigraphy indicates a relative sea-level fall since about 5000 years BP as evidenced by radiocarbon ages that constrain the peat-bearing sequences. Locally, low-intertidal silt and clay overlie high-intertidal peat layers, but such minor transgressions cannot be correlated from site to site. At Río Pudeto, the youngest foraminifera-bearing silt deposit is no younger than 1200 years BP. The youngest age of shells at Quetalmahue is about 2600 years BP. The oldest peat-bearing deposits that are not overlain by silt deposits are about 1350 years BP at Río Pudeto, and as old as 4900 years BP at Quetalmahue. At Río Pudeto, peat-bearing deposits, which are overlain by silt and clay, range in age from 760 to 5430 years BP, and at Quetalmahue from 290 to 5290 years BP. A beach terrace on the northwest coast of the Isla is estimated to have been emergent since 1150 + 130 years ago.Although some relatively abrupt transgressions may be due to sudden coseismic subsidence, data are not sufficient to document regional subsidence during individual plate-interface earthquakes. Seven earthquakes in south central Chile since 1520, especially those that occurred in 1575, 1737, and 1837, are thought to have been of a magnitude comparable to that of the 1960 earthquake. Although the sedimentological effects of the 1960 earthquake on the intertidal zone were dramatic, only limited evidence of possible historic earthquakes is found on Isla Chiloé and nearby islands; the ages and displacements of these earthquakes are

  20. Contextualization of HIV and HPV risk and prevention among Pacific Islander young adults in Southern California

    PubMed Central

    DiStefano, Anthony S.; Hui, Brian; Barrera-Ng, Angelica; Quitugua, Lourdes F.; Peters, Ruth; Dimaculangan, Jeany; Vunileva, Isileli; Tui’one, Vanessa; Takahashi, Lois M.; Tanjasiri, Sora Park

    2012-01-01

    HIV and sexually transmitted human papillomavirus (HPV) are associated with each other and with the development of comorbid cancer. Current epidemiology indicates that among Pacific Islanders in the United States, young adults are at highest risk of HIV and HPV. In our inductive community based participatory research study, we used focus groups and key informant interviews (March – August 2010) with young adults, parents, community leaders, and providers (n = 95) to identify and contextualize factors that shape HIV and HPV risk and prevention among young adults in Chamorro and Tongan communities in Southern California. We identified nine themes that incorporated the following principal factors: misinformation and otherization; dominant concerns regarding premarital pregnancy; restricted intergenerational communication; family shame and privacy; gendered manifestations of religio-cultural norms; barriers impeding access to sexual health resources; parents’ role in prevention; community vs. individual responsibility; and family and ethnic pride. Our thematic findings fit well with Rhodes’ “risk and enabling environment” heuristic (2009), which we used to contextualize risk and prevention at micro and macro levels of physical, social, economic, and policy environments. We propose the addition of a separate cultural environment to the heuristic and conclude that a focus on applying individual and community agency at the micro-level would be an approachable starting point for intervention for our local Pacific Islander communities and groups in similar ecological contexts globally. Enhanced community-led education programs and engagement of religious and other community leaders to facilitate intergenerational communication could counteract taboos that obstruct prevention. PMID:22647562

  1. Contextualization of HIV and HPV risk and prevention among Pacific Islander young adults in Southern California.

    PubMed

    DiStefano, Anthony S; Hui, Brian; Barrera-Ng, Angelica; Quitugua, Lourdes F; Peters, Ruth; Dimaculangan, Jeany; Vunileva, Isileli; Tui'one, Vanessa; Takahashi, Lois M; Tanjasiri, Sora Park

    2012-08-01

    HIV and sexually transmitted human papillomavirus (HPV) are associated with each other and with the development of comorbid cancer. Current epidemiology indicates that among Pacific Islanders in the United States, young adults are at highest risk of HIV and HPV. In our inductive community based participatory research study, we used focus groups and key informant interviews (March-August 2010) with young adults, parents, community leaders, and providers (n = 95) to identify and contextualize factors that shape HIV and HPV risk and prevention among young adults in Chamorro and Tongan communities in Southern California. We identified nine themes that incorporated the following principal factors: misinformation and otherization; dominant concerns regarding premarital pregnancy; restricted intergenerational communication; family shame and privacy; gendered manifestations of religio-cultural norms; barriers impeding access to sexual health resources; parents' role in prevention; community vs. individual responsibility; and family and ethnic pride. Our thematic findings fit well with Rhodes' "risk and enabling environment" heuristic (2009), which we used to contextualize risk and prevention at micro and macro levels of physical, social, economic, and policy environments. We propose the addition of a separate cultural environment to the heuristic and conclude that a focus on applying individual and community agency at the micro-level would be an approachable starting point for intervention for our local Pacific Islander communities and groups in similar ecological contexts globally. Enhanced community-led education programs and engagement of religious and other community leaders to facilitate intergenerational communication could counteract taboos that obstruct prevention.

  2. Seabirds modify El Niño effects on tree growth in a southern Pacific island.

    PubMed

    Molina-Montenegro, Marco A; Torres-Díaz, Cristian; Gallardo-Cerda, Jorge; Leppe, Marcelo; Gianoli, Ernesto

    2013-11-01

    Oceanic island ecosystems are particularly sensitive to El Niño effects due to their dependence on energy and nutrient inputs from marine systems. Seabirds play a key role in transporting resources of marine origin to insular ecosystems. We report tree-growth patterns showing how the effects of El Niño rainy events on tree species in a southern Pacific island depend on the presence of local seabird colonies. We performed manipulative experiments in order to assess the mechanisms underlying these patterns. Tree ring data showed that, in normal years, the growth of all tree species (Aextoxicon punctatum, Cryptocarya alba, and Pinus radiata) was significantly lower in seabird sites compared to adjacent patches without seabirds (control sites). In contrast, in El Niño years, trees formerly hosting seabird colonies grew more than those in control sites. Experiments showed that (1) pine plants on soil from seabird sites grew more than those on soil from control sites, (2) pine individuals with seabird feces on their leaves grew less than those sprayed with an aqueous solution, and (3) soil moisture had little effect on plant growth. The stress produced by massive cormorant nesting on trees, which impairs tree growth and physiological performance, is relieved during El Niño events because of seabird migration due to decreased prey availability and pouring rains that flood nests. Soils enriched by the seabird guano, together with the increased water availability associated with El Niño, foster the growth of trees from seabird sites. We suggest that El Niño may be a key determinant of tree performance in forest communities from island and coastal ecosystems of the Pacific Ocean.

  3. The basic reproduction number R0 and effectiveness of reactive interventions during dengue epidemics: the 2002 dengue outbreak in Easter Island, Chile.

    PubMed

    Chowell, Gerardo; Fuentes, R; Olea, A; Aguilera, X; Nesse, H; Hyman, J M

    2013-01-01

    We use a stochastic simulation model to explore the effect of reactive intervention strategies during the 2002 dengue outbreak in the small population of Easter Island, Chile. We quantified the effect of interventions on the transmission dynamics and epidemic size as a function of the simulated control intensity levels and the timing of initiation of control interventions. Because no dengue outbreaks had been reported prior to 2002 in Easter Island, the 2002 epidemic provided a unique opportunity to estimate the basic reproduction number R0 during the initial epidemic phase, prior to the start of control interventions. We estimated R0 at 27.2 (95%CI: 14.8, 49.3). We found that the final epidemic size is highly sensitive to the timing of start of interventions. However, even when the control interventions start several weeks after the epidemic onset, reactive intervention efforts can have a significant impact on the final epidemic size. Our results indicate that the rapid implementation of control interventions can have a significant effect in reducing the epidemic size of dengue epidemics.

  4. The Basic Reproduction Number ℛ0 and Effectiveness of Reactive Interventions during Dengue Epidemics: The 2002 Dengue Outbreak in Easter Island, Chile

    PubMed Central

    Chowell, G.; Fuentes, R.; Olea, A.; Aguilera, X.; Nesse, H.; Hyman, J. M.

    2015-01-01

    We use a stochastic simulation model to explore the effect of reactive intervention strategies during the 2002 dengue outbreak in the small population of Easter Island, Chile. We quantified the effect of interventions on the transmission dynamics and epidemic size as a function of the simulated control intensity levels and the timing of initiation of control interventions. Because no dengue outbreaks had been reported prior to 2002 in Easter Island, the 2002 epidemic provided a unique opportunity to estimate the basic reproduction number ℛ0 during the initial epidemic phase, prior to the start of control interventions. We estimated ℛ0 at 27.2 (95%CI: 14.8, 49.3). We found that the final epidemic size is highly sensitive to the timing of start of interventions. However, even when the control interventions start several weeks after the epidemic onset, reactive intervention efforts can have a significant impact on the final epidemic size. Our results indicate that the rapid implementation of control interventions can have a significant effect in reducing the epidemic size of dengue epidemics. PMID:24245625

  5. Hurricane Sandy washover deposit data from southern Long Beach Island, New Jersey: Grain-size, elevations, and graphic core logs

    USGS Publications Warehouse

    Bishop, James; Richmond, Bruce M.; Zaremba, Nicholas J.; Lunghino, Brent D.; Kane, Haunani H.

    2016-01-01

    Sedimentologic and topographic data from Hurricane Sandy washover deposits were collected from Southern Long Beach Island, New Jersey, in order to document changes to the barrier-island beaches, dunes, and coastal wetlands due to Hurricane Sandy and subsequent storm events. These data will provide a baseline dataset for use in future coastal change descriptive and predictive studies and assessments. The data presented here were collected as part of the U.S. Geological Survey’s Barrier Island and Estuarine Wetland Physical Change Assessment project (http://coastal.er.usgs.gov/sandy-wetland-assessment/), which aims to assess ecological and societal vulnerability that results from long- and short-term physical changes to barrier islands and coastal wetlands. In April 2015, approximately two and a half years after Hurricane Sandy’s landfall on 29 October 2012, washover deposits were photographed and described, and sediment cores, sediment samples, and surface elevations were collected.

  6. Bona fide evidence for natural vertical transmission of infectious salmon anemia virus in freshwater brood stocks of farmed Atlantic salmon (Salmo salar) in Southern Chile.

    PubMed

    Marshall, Sergio H; Ramírez, Ramón; Labra, Alvaro; Carmona, Marisela; Muñoz, Cristián

    2014-06-01

    Infectious salmon anemia (ISA) is a severe disease that affects farmed Atlantic salmon (Salmo salar), causing outbreaks in seawater in most salmon-producing countries worldwide, with particular aggressiveness in southern Chile. The etiological agent of this disease is a virus belonging to the Orthomyxoviridae family, named infectious salmon anemia virus (ISAV). Although it has been suggested that this virus can be vertically transmitted, even in freshwater, there is a lack of compelling experimental evidence to confirm this. Here we demonstrate significant putative viral loads in the ovarian fluid as well as in the eggs of two brood stock female adult specimens that harbored the virus systemically but without clinical signs. The target virus corresponded to a highly polymorphic region 3 (HPR-3) variant, which is known to be virulent in seawater and responsible for recent and past outbreaks of this disease in Chile. Additionally, the virus recovered from the fluid as well as from the interior of the eggs was fully infective to a susceptible fish cell line. To our knowledge, this is the first robust evidence demonstrating mother-to-offspring vertical transmission of the infective virus on the one hand and the asymptomatic transmission of a virulent form of the virus in freshwater fish on the other hand. The robustness of the data presented here will contribute to a better understanding of the biology of the virus but most importantly will constitute a key management tool in the control of an aggressive agent constantly threatening the sustainability of the global salmon industry.

  7. A 2 year record of atmospheric mercury species at a background Southern Hemisphere station on Amsterdam Island

    NASA Astrophysics Data System (ADS)

    Angot, H.; Barret, M.; Magand, O.; Ramonet, M.; Dommergue, A.

    2014-06-01

    Scarcity of mercury species records in the Southern Hemisphere is a critical weak point for the development of appropriate modeling and regulation scenarios. Under the framework of the "Global Mercury Observation System" (GMOS) project, a monitoring station has been set up on Amsterdam Island (37°48' S, 77°34' E) in the remote southern Indian Ocean. For the first time in the Southern Hemisphere, a 2 year record of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound mercury (PBM) is presented. GEM concentrations were remarkably steady (1.03 ± 0.08 pg m-3) while RGM and PBM concentrations were very low and exhibited a strong variability (mean: 0.34 pg m-3 [range: 0.28-4.07 pg m-3] and mean: 0.67 pg m-3 [range: 0.28-12.67 pg m-3], respectively). Despite the remoteness of the island, wind sector analysis, air mass back trajectories and the observation of radonic storms highlighted a long-range contribution from the southern African continent to the GEM and PBM budgets in winter during the biomass burning season. Lowest concentrations of GEM were associated with southerly polar and marine air masses from the remote southern Indian Ocean. This unique dataset provides new baseline GEM concentrations in the Southern Hemisphere mid-latitudes for further modeling studies, while mercury speciation along with upcoming wet deposition data will help improving our understanding of mercury cycle in the marine boundary layer.

  8. A 2-year record of atmospheric mercury species at a background Southern Hemisphere station on Amsterdam Island

    NASA Astrophysics Data System (ADS)

    Angot, H.; Barret, M.; Magand, O.; Ramonet, M.; Dommergue, A.

    2014-10-01

    Although essential to fully understand the cycling of mercury at the global scale, mercury species records in the Southern Hemisphere are scarce. Under the framework of the Global Mercury Observation System (GMOS) project, a monitoring station has been set up on Amsterdam Island (37°48´ S, 77°34´ E) in the remote southern Indian Ocean. For the first time in the Southern Hemisphere, a 2-year record of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound mercury (PBM) is presented. GEM concentrations were remarkably steady (1.03 ± 0.08 ng m-3) while RGM and PBM concentrations were very low and exhibited a strong variability (mean: 0.34 pg m-3, range: < detection limit-4.07 pg m-3; and mean: 0.67 pg m-3, range: < detection limit-12.67 pg m-3, respectively). Despite the remoteness of the island, wind sector analysis, air mass back trajectories and the observation of radonic storms highlighted a long-range contribution from the southern African continent to the GEM and PBM budgets from July to September during the biomass burning season. Low concentrations of GEM were associated with southerly polar and marine air masses from the remote southern Indian Ocean. This unique data set provides new baseline GEM concentrations in the Southern Hemisphere midlatitudes while mercury speciation along with upcoming wet deposition data will help to improve our understanding of the mercury cycle in the marine boundary layer.

  9. The mosses (Bryophyta) of Capitán Prat Province, Aisén Region, southern Chile

    PubMed Central

    Larraín, Juan

    2016-01-01

    Abstract The bryophytes of Capitán Prat province have remained one of the least explored in Chile. The eventual construction of several dams on the rivers Baker and Pascua required prospection of all groups of organisms including bryophytes, work that was facilitated by the recent construction of vehicular roads that now offer easy access to previously almost unaccessible locations. The results of intense bryophyte collecting during the austral summer of 2007 are here presented. A total of 260 moss taxa are reported for the province, corresponding to 256 species and four infraspecific taxa, of which 211 are new records for the province, 54 are new for Aisén Region, and two are new records for continental Chile (Pohlia longicollis (Hedw.) Lindb. and Rigodium toxarion var. robustum (Broth.) Zomlefer). Twelve species extend their known distribution ranges to the north, whereas 49 extend them to the south. PMID:27698577

  10. The mosses (Bryophyta) of Capitán Prat Province, Aisén Region, southern Chile.

    PubMed

    Larraín, Juan

    2016-01-01

    The bryophytes of Capitán Prat province have remained one of the least explored in Chile. The eventual construction of several dams on the rivers Baker and Pascua required prospection of all groups of organisms including bryophytes, work that was facilitated by the recent construction of vehicular roads that now offer easy access to previously almost unaccessible locations. The results of intense bryophyte collecting during the austral summer of 2007 are here presented. A total of 260 moss taxa are reported for the province, corresponding to 256 species and four infraspecific taxa, of which 211 are new records for the province, 54 are new for Aisén Region, and two are new records for continental Chile (Pohlia longicollis (Hedw.) Lindb. and Rigodium toxarion var. robustum (Broth.) Zomlefer). Twelve species extend their known distribution ranges to the north, whereas 49 extend them to the south.

  11. Antioxidant capacity and HPLC-DAD-MS profiling of Chilean peumo (Cryptocarya alba) fruits and comparison with German peumo (Crataegus monogyna) from southern Chile.

    PubMed

    Simirgiotis, Mario J

    2013-02-05

    Liquid chromatography (LC) coupled with UV detection and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for the generation of chemical fingerprints and the identification of phenolic compounds in peumo fruits and aerial parts from southern Chile. Thirty three compounds (19 of these detected in C. alba and 23 in C. monogyna) were identified, mainly flavonoid glycosides, phenolic acids, anthocyanins and flavonoid aglycons. Total phenolic content and total flavonoid content was measured for both species, and were higher in the extracts from C. monogyna fruits and aerial parts than extracts from C. alba. The fruits of Cryptocarya alba (Chilean peumo) presented high antioxidant capacity (9.12 ± 0.01 mg/mL in the DPPH assay), but was three times lower to that of Crataegus monogyna (German peumo) (3.61 ± 0.01 mg/mL in the DPPH assay).

  12. [Fish community structure and its seasonal change in subtidal sandy beach habitat off southern Gouqi Island].

    PubMed

    Wang, Zhen-Hua; Wang, Kai; Zhao, Jing; Zhang, Shou-Yu

    2011-05-01

    To understand the characteristics of fish community structure in sandy beach habitats of island reef water areas, and to evaluate the potential capacity of these habitats in local fish stock maintenance, fishes were monthly collected with multi-mesh trammel nets in 2009 from the subtidal sandy beach habitat off southern Gouqi Island, taking the adjacent rocky reef habitat as the control. alpha and beta species diversity indices, index of relative importance (IRI), relative catch rate, and dominance curve for abundance and biomass (ABC curve) were adopted to compare the fish species composition, diversity, and community pattern between the two habitats, and multivariate statistical analyses such as non-metric multidimensional scaling (nMDS) and cluster were conducted to discuss the fish assemblage patterns. A total of 63 fish species belonging to 11 orders, 38 families, and 56 genera were collected, of which, 46 fish species were appeared in the two habitats. Due to the appearance of more warm water species in sandy bottom, the fishes in subtidal sandy beach habitat showed much higher richness, and the abundance catch rate (ACR) from May to July was higher than that in rocky reef habitat. In most rest months, the ACR in subtidal sandy beach habitat also showed the similar trend. However, the species richness and diversity in spring and summer were significantly lower in subtidal sandy beach habitat than in rocky reef habitat, because of the high species dominance and low evenness in the sandy beach habitat. Japanese tonguefish (Paraplagusia japonica) was the indicator species in the sandy beach habitat, and dominated in early spring, later summer, autumn, and winter when the fishing pressure was not strong. In sandy bottom, a unique community structure was formed and kept in dynamic, due to the nursery use of sandy beach by Japanese anchovy (Engraulis japonicus) from May to July, the gathering of gray mullet (Mugil cephalus) in most months for feeding, and the large

  13. Two new species of the Liolaemus elongatus-kriegi complex (Iguania, Liolaemidae) from Andean highlands of southern Chile

    PubMed Central

    Troncoso-Palacios, Jaime; Díaz, Hugo A.; Esquerré, Damien; Urra, Felix A.

    2015-01-01

    Abstract The elongatus-kriegi complex is one of the most diverse clades of the Liolaemus (sensu stricto) subgenus of lizards. There are currently 29 species recognized in this group distributed between Chile and Argentina. Based on molecular evidence, there seem to be five main clades nested within this complex: the elongatus, leopardinus, kriegi, petrophilus and punmahuida clades. Liolaemus buergeri and Liolaemus kriegi, both of the kriegi clade, were believed to inhabit the surroundings of the Laja Lagoon, in the Biobío Region of Chile. Moreover, this Chilean population of Liolaemus kriegi was recently recognized as an undescribed taxon called “Liolaemus sp. A” based on molecular phylogenetics. In this work, we studied these two populations of the Laja Lagoon and provided the morphological diagnosis to describe them as two new species: Liolaemus scorialis sp. n. and Liolaemus zabalai sp. n., previously considered Liolaemus buergeri and “Liolaemus kriegi/Liolaemus sp. A” respectively. Additionally, we identified another population of Liolaemus scorialis in the vicinity of La Mula Lagoon in the Araucanía Region of Chile. Liolaemus scorialis differs from almost all of the species of the elongatus-kriegi complex by its considerably smaller size. Nevertheless, without molecular data we cannot assign it to any particular subclade. Liolaemus zabalai belongs to the kriegi clade based on published molecular phylogenies. Finally, we provide some natural history data on both species and we document for the first time the presence of Liolaemus neuquensis in Chile from a museum specimen from La Mula Lagoon. PMID:25987873

  14. Tsunamogenic landslides and marine paleoseismology: applications of the submerged marine terrace record, Santa Catalina Island, Southern California Borderland

    NASA Astrophysics Data System (ADS)

    Castillo, C. M.; Klemperer, S. L.; Williams, E.; Legg, M.; Francis, R. D.

    2015-12-01

    Transpressional structures related to deformation along the Greater San Andreas Fault are largely responsible for creating the complex morphology and steep topography in the Southern California Borderland. The numerous anastamosing strike slip faults dissecting the area are responsible for creating its complex morphology and present a seismic hazard to nearshore communities. Submarine slope failures tend to nucleate on faulted steep topography and could generate a tsunami dangerously close to densely populated urban areas. We present evidence for a tsunamogenic landslide originating from Catalina Island and directed toward the mainland. Radiometric dates of fossils collected during coring cruises and ROV dives during 2014-15 provide age control for high-resolution 2D and 3D seismic reflection profiles collected near Santa Catalina Island and Pilgrim Banks. These refine our established sequence stratigraphic subsidence history for Catalina Island, and enable us to constrain the timing of the landslide deposit, as well as other landslide deposits and faults. Although the slide is pre-Holocene, the threat of another tsunamogenic landslide directed at urban southern California is increased by gradual tilting of the Catalina block toward mainland California. Our study demonstrates that investigations using a combination of bathymetry, 2D and 3D MCS can be used to map submerged marine terrace deposits and those can then be used as offset markers for paleoseismic investigations. The subsided marine terrace record has potential paleoseismologic applications on over 20 submerged seamounts and islands in Southern California, as well as applications in providing constraints on Quaternary sea level history.

  15. Recent changes in total ice volume storage on Volcán Villarrica, Southern Chile, by means of airborne radar and lidar surveys

    NASA Astrophysics Data System (ADS)

    Rivera, Andrés; Zamora, Rodrigo; Andrés Uribe, José; Wendt, Anja; Oberreuter, Jonathan; Cisternas, Sebastián; Gimeno, Fernando; Clavero, Jorge

    2014-05-01

    Numerous active ice-capped volcanoes are found along the Southern Volcanic Zone (SVZ, 36-46°S) of Chile. Because they represent a potential natural hazard during eruptive events, when glaciers are susceptible to rapid melting, leading to laharic flows, knowledge upon the ice volume storage and their changes is therefore, very relevant in terms of risk assessment studies. We present the first intensive airborne surveys carried out at Volcán Villarrica (39ºS) in Southern Chile, one of the main active ice-capped volcanoes and lahar generator within historical times within the SVZ. We deployed a scanner laser system for detecting the glacier surface topography, and helicopter-borne ice penetrating radar, for measuring ice thicknesses, allowing altogether to determine the volume of snow and ice storage susceptible to be melted during eruptive events. The total estimated volume resulted in 1.17± 0.1 km3 of water equivalent (w.eq.) at the volcano in 2012, only 37% of the estimated volume of 1961. This reduction is mainly explained by the area shrinkage and ice thinning rates observed in the last 51 years. This total volume is the lower bound available for melting during eruptive events when lahars mudows can be generated, because in the winter, nearly 0.14 km3 w.eq. are potentially added to the volcano as temporal snow falls. The decreasing volume of water equivalent does not mean a lower risk associated to these flows because there has been a huge increase in populated areas and tourism industry in the surroundings of the volcano in recent years.

  16. Water Input and Water Release from the Subducting Nazca Plate along Southern Central Chile (33°S-46°S)

    NASA Astrophysics Data System (ADS)

    Voelker, D.; Stipp, M.

    2015-12-01

    The fixation of water in the oceanic crust and upper mantle, the flux of stored water into subduction zones and the partial liberation of those fluids underneath the forearc and arc are mechanisms that impact on almost every aspect of subduction zone processes, e.g. intensity and type of arc volcanism, deposition of ores and seismicity of the subduction fault, but also on global geochemical budgets by recycling material back into the continental crust. Much of that water fixation happens at the outer rise of subduction zones in particular by deep percolation of fluids to the upper mantle along bend faults. Offshore Chile, the age of the subducting Nazca Plate varies between 0 Ma at the Chile Triple Junction (46°S) and ~38 Ma at the latitude of Valparaíso (32°S). Age-related variations in the thermal state of the subducting Nazca Plate impact on the water influx to the subduction zone, as well as the volumes of water that are released under the continental forearc or, alternatively, carried into the deeper mantle. Southern Central Chile is an ideal setting to study this effect, because other factors important for the subduction zone water budget appear constant. We determine the water influx by calculating the crustal water uptake and by modeling the upper mantle serpentinization at the outer rise of the Chile Trench. The water release under forearc and arc is determined by coupling FEM thermal models of the subducting plate with stability fields of water-releasing mineral reactions for upper and lower crust and hydrated mantle. Results show that both the influx and the release of water vary drastically over a length of 1500 km. In particular, the oldest and coldest segments carry roughly twice as much water into the subduction zone as the youngest and hottest segments, but their release flux to the forearc is only about one fourth of the latter. This high variability over a subduction zone of ~1500 km length shows that it is insufficient to consider subduction

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

    PubMed Central

    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

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

    PubMed

    González-Wevar, Claudio A; 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.

  19. Effects of isolation and fishing on the marine ecosystems of Easter Island and Salas y Gómez, Chile

    USGS Publications Warehouse

    Friedlander, Alan M.; Ballesteros, Enric; Beets, Jim; Berkenpas, Eric; Gaymer, Carlos F.; Gorny, Matthias; Sala, Enric

    2013-01-01

    1. An expedition to Salas y Gómez and Easter islands was conducted to develop a comprehensive baseline of the nearshore marine ecosystem, to survey seamounts of the recently created Motu Motiro Hiva Marine Park (MMHMP) – a no-take marine reserve of 150 000 km2 – and to compare these results with Easter Island where the marine ecosystem is similar but has no marine protection. 2. Live coral cover was surprisingly high at both Easter Island (53%) and Salas y Gómez (44%), especially considering their sub-tropical location, high wave energy environments, and geographic isolation. 3. Endemic and regionally-endemic species comprised 77% of the fish abundance at Easter Island and 73% at Salas y Gómez. Fish biomass at Salas y Gómez was relatively high (1.2 t ha-1) and included a large proportion of apex predators (43%), whereas at Easter Island it was almost three times lower (0.45 t ha-1) with large predators accounting for less than 2% of the biomass, despite good habitat quality. 4. The large cohort of small sharks and the absence of larger sharks at Salas y Gómez suggest mesopredator release consistent with recent shark fishing. The fish fauna at the seamounts between Easter Island and Salas y Gómez, outside of MMHMP, harboured 46% endemic species, including a new species of damselfish (Chromis sp. nov.) and probably a new species of Chimaera (Hydrolagus). Numerous seamounts adjacent to Salas y Gómez are currently not included in the MMHMP. 5. This expedition highlights the high biodiversity value of this remote part of the Pacific owing to the uniqueness (endemicity) of the fauna, large apex predator biomass, and geographic isolation.

  20. Elevated reefs and related Pleistocene stratigraphy of the southern Exuma Islands, Bahamas

    SciTech Connect

    Dill, R.F. Caribbean Marine Research Center, San Diego, CA ); Halley, R.B.; Shinn, E.A.; Kindinger, J.L. ); Muhs, D.R. )

    1991-03-01

    At least seven elevated coral reefs are exposed on the lee side of an inner chain of low islands on the eastern margin of Great Bahama Bank in the Southern Exumas. Starting at Fowl Cay in the north, they extend at least to Pigeon Cay in the south, a distance of about 44 nautical mi (81 km). These reefs formed around preexisting Pleistocene core-islands and hardgrounds during a transgressive higher than present stand of sea level, prior to the Holocene. As sea level dropped, the reefs were karstedand capped by caliche crusts, a unique paleosol breccia containing land snails (Cerithidea. sp.) and a now lithified dune system with well-developed rhizomorphs. Shallow sea caves eroded into steep, clifflike notches are often located on ridges shoreward of the reef, with roof heights of up to 5 m above the top of the elevated reefs. The reefs form a 5- to 10-m wide terrace, approximately 1 m above present sea level. Shoreline exposures often exceed 300 m (1,000 ft). Most exposures have a base thicket of interwoven branches of Acropora cervicornus approximately 70-cm thick. The badly corroded branches are surrounded by a cemented matrix of ooid sands, marine cement, and coralline debris. The upper 30 cm is formed by a much more diverse reef community of broken shells and corals (Montastrea, Diploria Agaricia, Porites, and Acropora). Crustose coralline algae and colonial foraminifera (Homotrema) form a cementing crust around many corals. These reefs and their relationship to paleosols within subaerial dune deposits provide stratigraphic markers that play an important role in interpreting the development of Pleistocene deposits of the Great Bahama Bank.

  1. Discovery Of Pre-2004 Tsunami Deposits On Simeulue Island, Southern Aceh Province, Indonesia

    NASA Astrophysics Data System (ADS)

    Fujino, S.; Sieh, K.; Meltzner, A. J.; Yulianto, E.; Whitlow, K.; Putra, A.; Satake, K.

    2007-12-01

    Presumably, megathrust earthquakes and tsunamis occurred repeatedly along the Sunda megathrust before 2004 and 2005. To determine its past tsunami history, we conducted field surveys on Simeulue Island, which straddles the boundary of the 2004 and 2005 ruptures. Shallow excavations exposed paleo-tsunami deposits at two coastal lowland sites in southern Simeulue Island. The paleo-tsunami deposits at the Inor-Naibos and Busong Bay sites appear as laterally continuous sand layers in terrestrial sedimentary successions. Two paleo-tsunami layers exist at Busong Bay; the younger one is bounded by peat layers and the older one separates peat and underlying muddy sediment that was probably deposited in an inter-tidal or sub-tidal environment. Both tsunami deposits are rich in coral clasts. A fresh, uneroded coral boulder from the upper tsunami layer yielded a U/Th age that is consistent with emplacement in 1861, the year of an historical great (M-8.5) earthquake there. The lower tsunami layer may have been emplaced during an earlier uplift event around A.D. 1799, documented by an uplifted coral microatoll at the site. This interpretation is consistent with the sedimentary facies change from mud to peat across the lower tsunami layer, which probably represents an environmental change due to uplift. The single tsunami layer at the Inor-Naibos site demarcates a sedimentary facies change. As at Busong Bay, it is accompanied by coral boulders, which we think are likely to yield U/Th ages consistent with deposition contemporaneous with one of the layers at Busong Bay.

  2. Coral communities of the remote atoll reefs in the Nansha Islands, southern South China Sea.

    PubMed

    Zhao, M X; Yu, K F; Shi, Q; Chen, T R; Zhang, H L; Chen, T G

    2013-09-01

    During the months of May and June in the year 2007, a survey was conducted regarding coral reef communities in the remote atolls (Zhubi Reef and Meiji Reef) of Nansha Islands, southern South China Sea. The goals of the survey were to: (1) for the first time, compile a scleractinian coral check-list; (2) estimate the total richness, coral cover, and growth forms of the community; and (3) describe preliminary patterns of community structure according to geomorphological units. Findings of this survey revealed a total of 120 species of scleractinia belonging to 40 genera, while the average coral cover was 21 %, ranging from less than 10 % to higher than 50 %. Branching and massive corals were also found to be the most important growth forms of the whole coral community, while Acropora, Montipora, and Porites were the three dominant genera in the overall region, with their contributions to total coral cover measuring 21, 22, and 23 %, respectively. Overall, coral communities of the Nansha Islands were in a relative healthy condition with high species diversity and coral cover. Spatial pattern of coral communities existed among various geomorphological units. Mean coral cover was highest in the patch reef within the lagoon, followed by the fore reef slope, reef flat, and lagoon slope. The greatest contributors to total coral cover were branching Acropora (45 %) in the lagoon slope, branching Montipora (44 %) in the reef flat, and massive Porites (51 %) in the patch reef. Coral cover in the fore reef revealed a greater range of genera than in other habitats. The leeward fore reef slope had higher coral cover (> 50 %) when compared with the windward slope (< 10 %). The coral communities of the inner reef flat were characterized by higher coral cover (27 %) and dominant branching Montipora corals, while lower coral cover (4 %) was dominated by Psammocora with massive growth forms on the outer reef flat. Destructive fishing and coral bleaching were two major threats to

  3. Cool-water Eocene-Oligocene carbonate sedimentation on a paleobathymetric high, Kangaroo Island, southern Australia

    NASA Astrophysics Data System (ADS)

    James, Noel P.; Matenaar, Joanne; Bone, Yvonne

    2016-07-01

    The Kingscote Limestone is a thin, biofragmental 41 m thick Paleogene subtropical to cool-temperate carbonate interpreted to have accumulated in a seaway developed between a series of mid-shelf islands. It is a pivotal section that allows interpretation of a region in which there is little exposure of early Cenozoic shelf sediments. Sedimentation occurred on part of the shelf along the northern margin of an extensive Eocene embayment that evolved into a narrow Oligocene ocean following collapse of the Tasman Gateway. Eocene strata are subtropical echinoid-rich floatstones with conspicuous bryozoans, and mollusks, together with large and small benthic foraminifers. Numerous echinoid rudstone storm deposits punctuate the succession. Correlation with coeval Eocene strata across southern Australia supports a regional facies model wherein inner neritic biosiliceous spiculitic sediments passed outboard into calcareous facies. The silica was derived from land covered by a thriving subtropical forest and attendant deep weathering. Oligocene rocks are distinctively cooler cyclic cross-bedded bryozoan rudstones and floatstones with a similar benthic biota but dominated by bryozoans and containing no large benthic foraminifers. These deposits are interpreted as flood-dominated tidal subaqueous dunes that formed in a flood-tide dominated inter-island strait. Omission surfaces at the top of the Eocene and at the top of most Oligocene cycles are Fe-stained hardgrounds that underwent extensive multigeneration seafloor and meteoric diagenesis prior to deposition of the next cycle. Cycles in the Kingscote Limestone, although mostly m-scale and compositionally distinct are similar to those across the region and point to a recurring cycle motif controlled by icehouse eustasy and local paleogeography.

  4. Demographic factors and land-use planning in the small islands of Southern Europe

    NASA Astrophysics Data System (ADS)

    Soliani, Lamberto; Rossi, Orazio

    1992-09-01

    Since the end of the 1970s, the southern European countries have shown an exceptional reduction in fertility rate. From the highest levels among the developed nations, these countries dropped beneath the substitution rate level: in Greece there is an average of about 1.5 children per woman, and Italy (starting three to four years ago), with 1.3 children per woman, is now the country with the lowest fecundity rate in the world. Land-use planning in southern European small islands therefore requires substantial revision. In the areas where western civilization began, which are highly populated and have a long history, cultural and ethnic aspects of tradition are fundamental to environmental management and to the defense of historical heritage. They also place a strong value on sustaining tourism, the most relevant economic activity, that allows them to survive and maintain a high welfare level. For some decades they have had populations with a marked presence of young people and high emigration rates, but now they are fast becoming dominated by the elderly and must prepare for a period of fast reduction in youth of the workforce, while the peripheral areas of Asia and Africa are entering a sudden demographic growth phase. The demographic structure has also been deeply altered both by previous migrations and by random variations, as usually happens in all small communities. Social services for younger and older people have had to be adapted rapidly, reorganizing high-school management, hospital and health-care structures, in-house assistance, and so on. There is a need to rethink the job market and favor the immigration of highly specialized workers, which is a necessity for technical evolution. Sustainable development is constrained nowadays not only by the scarcity of natural resources, but also by the quality and quantity of human resources. Proper policies for population and land-use planning are highly correlated factors; they have to be considered with respect

  5. Metamorphism within the Chugach accretionary complex on southern Baranof Island, southeastern Alaska

    USGS Publications Warehouse

    Zumsteg, Cathy L.; Himmelberg, Glen R.; Karl, Susan M.; Haeussler, Peter J.

    2003-01-01

    On Baranof Island, southeastern Alaska, we identify four metamorphic events that affect rocks associated with the Chugach accretionary complex. This study focuses on the M1 and M4 metamorphic events. Mesozoic schists, gneisses, and migmatitic gneisses exposed near the Kasnyku pluton on central Baranof Island represent the M1 metamorphic rocks. These rocks underwent amphibolite facies metamorphism. Calculated temperatures and pressures range from about 620 to 780 ºC and 5.5 to 6.6 kbar and are compatible with the observed metamorphic mineral assemblages.The M4 metamorphism affected rocks of the Sitka Graywacke on southern Baranof Island, producing extensive biotite and garnet zones as well as andalusite and sillimanite zones at the contacts of the Crawfish Inlet and Redfish Bay plutons. Calculated M4 temperatures and pressures from the andalusite and sillimanite zones range from 575 to 755 ºC and 3.4 to 6.9 kbar. These results fall within the sillimanite stability field, at pressures higher than andalusite stability. These results may indicate the M4 metamorphic event occurred along a P-T path along which the equilibration of aluminosilicate-garnet-plagioclase-quartz did not occur or was not maintained. This interpretation is supported by the occurrence of andalusite and sillimanite within the same sample. We propose the data reflect a clockwise P-T path with peak M4 metamorphism of the sillimanite-bearing samples adjacent to the intrusions at an approximate depth of 15 to 20 km, followed by rapid uplift without reequilibration of garnet-plagioclase-aluminosilicate-quartz.The large extent of the biotite zone, and possibly the garnet zone, suggests that an additional heat source must have existed to regionally metamorphose these rocks during the M4 event. We suggest the M4 regional thermal metamorphism and intrusion of the Crawfish Inlet and Redfish Bay plutons were synchronous and the result of heat flux from a slab window beneath the accretionary complex at that

  6. Morphostructural analysis and Cenozoic evolution of Elephant Island, Southern Scotia Arc, Antarctica

    NASA Astrophysics Data System (ADS)

    Mink, S.; Maestro, A.; López-Martínez, J.; Schmid, T.; Galindo-Zaldívar, J.; Trouw, R. A. J.

    2015-04-01

    Elephant Island, located in the vicinity of the present-day active boundary of the South Shetland Block and the Antarctic and Scotia plates, is a region of particular interest for understanding the past and present geodynamic evolution of the southern Scotia Arc. Lineament from different data sources, field-measured fractures and geomorphological evidences have been analysed in this context. The lineaments extracted from aerial photographs (1,624), from a DEM (348) and from RADARSAT-2 satellite data (1,365) indicate four dominant lineament sets with NE-SW, NW-SE, N-S and W-E strikes. All data sources identified similar lineament families, but differences in the frequency distributions and subsequently on the dominant orientations were observed. The measurements direct of fractures were obtained from 23 sites in the field at which 278 planes were measured. Fracture planes indicate main modes trending in the NNE-SSW and NNW-SSE directions and a secondary mode in the E-W. The major trends of the fracture measurements and the lineaments display a good correlation in the E-W direction. However, there is an angular variation in the azimuth values of the NNE-SSE and NNW-SSE fractures with respect to the N-S, NE-SW and NW-SE orientations of the lineaments of approximately 20°. This trend deviation may be due to the fact that mapped lineaments are composed of small fracture sets that may be related to shear fractures that cannot be distinguished at the aerial photograph or radar satellite data scales. Submerged sea-floor morphological feature orientations match the studied morphostructures on the island and the main tectonic structures in this part of the Scotia Arc. A linkage of the main lineament families to the tectonic stages from the Oligocene to the present has been proposed, taking into account the information of the orientation and sense of movement of the fractures and stresses in the Elephant Island region.

  7. Possible structural control on the 2011 eruption of Puyehue-Cordón Caulle Volcanic Complex (southern Chile) determined by InSAR, GPS and seismicity

    NASA Astrophysics Data System (ADS)

    Wendt, Anja; Tassara, Andrés; Báez, Juan Carlos; Basualto, Daniel; Lara, Luis E.; García, Francisco

    2016-09-01

    The Puyehue-Cordón Caulle Volcanic Complex (PCCVC) is one of the best examples of tectonic control on volcanism at the Southern Volcanic Zone of the Andes (southern Chile). The PCCVC comprises several volcanic centres that erupted dominantly SiO2-rich magmas at the intersection of the trench-parallel Liquiñe-Ofqui Fault Zone (LOFZ) and an inherited NW-SE basement structure. The PCCVC began an explosive and later effusive eruption on 4 June 2011 causing decimetre- to metre-scale surface deformation that was observed by a series of Envisat ASAR satellite scenes. We modelled this data and complemented it with time series of two continuous GPS stations and seismicity recorded by a local network. Deformation during the first three days of the eruption can be modelled either by two point sources aligned with the NW-SE Cordón Caulle graben or by a closing dike with a significant component of left-lateral motion along the graben. These models are discussed with respect to their implications on the estimated rheology and the eruption mechanism. GPS observations near the volcanic complex reveal an additional, more localised effect related to the LOFZ in the south of the complex. Coeruptive deformation at the main geological structures of the PCCVC is further supported by relocated seismicity, which is concentrated along the Cordón Caulle graben and to the western side of the LOFZ.

  8. Possible structural control on the 2011 eruption of Puyehue-Cordón Caulle Volcanic Complex (southern Chile) determined by InSAR, GPS and seismicity

    NASA Astrophysics Data System (ADS)

    Wendt, Anja; Tassara, Andrés; Báez, Juan Carlos; Basualto, Daniel; Lara, Luis E.; García, Francisco

    2017-01-01

    The Puyehue-Cordón Caulle Volcanic Complex (PCCVC) is one of the best examples of tectonic control on volcanism at the Southern Volcanic Zone of the Andes (southern Chile). The PCCVC comprises several volcanic centres that erupted dominantly SiO2-rich magmas at the intersection of the trench-parallel Liquiñe-Ofqui Fault Zone (LOFZ) and an inherited NW-SE basement structure. The PCCVC began an explosive and later effusive eruption on 2011 June 4 causing decimetre- to metre-scale surface deformation that was observed by a series of Envisat ASAR satellite scenes. We modelled this data and complemented it with time-series of two continuous GPS stations and seismicity recorded by a local network. Deformation during the first 3 days of the eruption can be modelled either by two point sources aligned with the NW-SE Cordón Caulle graben or by a closing dyke with a significant component of left-lateral motion along the graben. These models are discussed with respect to their implications on the estimated rheology and the eruption mechanism. GPS observations near the volcanic complex reveal an additional, more localised effect related to the LOFZ in the south of the complex. Coeruptive deformation at the main geological structures of the PCCVC is further supported by relocated seismicity, which is concentrated along the Cordón Caulle graben and to the western side of the LOFZ.

  9. Persistent organic pollutants in blood samples of Southern Giant Petrels (Macronectes giganteus) from the South Shetland Islands, Antarctica.

    PubMed

    Colabuono, Fernanda I; Vander Pol, Stacy S; Huncik, Kevin M; Taniguchi, Satie; Petry, Maria V; Kucklick, John R; Montone, Rosalinda C

    2016-09-01

    Seabirds play an important role as top consumers in the food web and can be used as biomonitors of exposure to pollutants. Contamination studies involving non-destructive sampling methods are of considerable importance, allowing better evaluation of the levels of pollutants and their toxic effects. In the present study, organohalogen contaminants were analyzed in 113 blood samples from Southern Giant Petrel (Macronectes giganteus) adults and chicks collected in the austral summer of 2011/2012 and 2012/2013 from colonies on Elephant and Livingston Islands, South Shetland, Antarctica. Polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), mirex, dichlorodiphenyltrichloroetane and derivatives (DDTs) and chlordanes were detected in all birds, whereas polybrominated diphenyl ethers (PBDEs) were not detected in any blood samples. No significant differences were found in organochlorine levels between sampling events. Adults exhibited significantly higher levels than chicks, except for PeCB. PCBs, HCB, mirex and DDTs were statistically similar in males and females from Elephant Island. Females on Livingston Island exhibited higher HCB values than males, but no sex differences were found regarding other organochlorines. The similarity in organochlorine levels between sexes in birds with very marked sexual segregation in feeding habits during the breeding season may indicate that significant amounts of contaminants are acquired during migration to lower latitudes, when the diets of males and females are similar. Birds sampled on Livingston Island exhibited significantly lower levels of PCBs, HCB, DDTs, mirex and chlordanes in comparison to those on Elephant Island, which could be the result of distinct foraging patterns between the two colonies. Organochlorine levels were similar between years in birds captured in two consecutive breeding seasons. Blood samples from Southern Giant Petrels adults and chicks proved to be useful for the comparison

  10. Source correlation of biomarkers in a mangrove ecosystem on Santa Catarina Island in southern Brazil.

    PubMed

    Silva, Cesar A; Madureira, Luiz A S

    2012-09-01

    The relative distribution of several compounds identified in four samples of recently deposited sediments of the Itacorubi Mangrove located on the Santa Catarina Island, southern Brazil, was compared with similar data on compounds extracted from fresh leaves of three mangrove species (Avicennia schaueriana, the dominant species in the area, Rhizophora mangle and Laguncularia racemosa) and the Gramineae Spartinna alterniflora. Terpenols, previously identified in mangrove species in northern Brazil, were also found. A. schaueriana mainly contains β-amyrin (90.6 μg g(-1) of extractable organic matter); low amounts of friedelin, betulin and germanicol were detected only in the leaf extract of this species. R. mangle also contained a significant amount of β-amyrin and it was the only species where taraxerol was detected. In contrast to the leaves, sediment extracts were dominated by germanicol, α-amyrin and campesterol. Despite its chemical lability, betulin was also detected. Two homologous series of α and ω-hydroxy fatty acids were detected in the acid-alkaline fraction. In spite of being reported in the literature as components of terrigenous plants, saturated ω-hydroxy acids were not identified. Our results indicate that although triterpenols may be used as biomarkers for mangrove-derived organic matter, their relative distribution can change according to the region.

  11. Sea-floor morphology and sedimentary environments in southern Narragansett Bay, Rhode Island

    USGS Publications Warehouse

    McMullen, Katherine Y.; Poppe, Lawrence J.; Blackwood, Dann S.; Nardi, Matthew J.; Andring, Matthew A.

    2015-09-09

    Multibeam echosounder data collected by the National Oceanic and Atmospheric Administration along with sediment samples and still and video photography of the sea floor collected by the U.S. Geological Survey were used to interpret sea-floor features and sedimentary environments in southern Narragansett Bay, Rhode Island, as part of a long-term effort to map the sea floor along the northeastern coast of the United States. Sea-floor features include rocky areas and scour depressions in high-energy environments characterized by erosion or nondeposition, and sand waves and megaripples in environments characterized by coarse-grained bedload transport. Two shipwrecks are also located in the study area. Much of the sea floor is relatively featureless within the resolution of the multibeam data; sedimentary environments in these areas are characterized by processes associated with sorting and reworking. This report releases bathymetric data from the multibeam echosounder, grain-size analyses of sediment samples, and photographs of the sea floor and interpretations of the sea-floor features and sedimentary environments. It provides base maps that can be used for resource management and studies of topics such as benthic ecology, contaminant inventories, and sediment transport.

  12. Successful foraging zones of southern elephant seals from the Kerguelen Islands in relation to oceanographic conditions.

    PubMed

    Bailleul, Frédéric; Charrassin, Jean-Benoît; Monestiez, Pascal; Roquet, Fabien; Biuw, Martin; Guinet, Christophe

    2007-11-29

    Southern elephant seals, Mirounga leonina, undertake large-scale oceanic movements to access favourable foraging areas. Successful foraging areas of elephant seals from the Kerguelen Islands are investigated here in relation to oceanographic parameters. Movements and diving activity of the seals as well as oceanographic data were collected through a new generation of satellite relayed devices measuring and transmitting locations, pressure, temperature and salinity. For the first time, we have associated foraging behaviour, determined by high increased sinuosity in tracks, and dive density (i.e. number of dives performed per kilometre covered), and changes in body condition, determined by variations in drift rate obtained from drift dives, to identify the oceanographic conditions of successful foraging zones for this species. Two main sectors, one close to the Antarctic continent and the other along the Polar Front (PF), where both foraging activity and body condition increase, seem to be of particular interest for the seals. Within these regions, some seals tended to focus their foraging activity on zones with particular temperature signatures. Along the Antarctic continent, some seals targeted colder waters on the sea bottom during benthic dives, while at the PF the favourable zones tended to be warmer. The possible negative effect of colder waters in Antarctic on the swimming performances of potential fish or squid prey could explain the behaviour of elephant seals in these zones, while warmer waters within the PF could correspond to the optimal conditions for potential myctophid prey of elephant seals.

  13. Prevalence, risk factor analysis, and hematological findings of hemoplasma infection in domestic cats from Valdivia, Southern Chile.

    PubMed

    Walker Vergara, Romina; Morera Galleguillos, Francisco; Gómez Jaramillo, Marcelo; Pereira Almosny, Nadia Regina; Arauna Martínez, Pía; Grob Behne, Paulina; Acosta-Jamett, Gerardo; Müller, Ananda

    2016-06-01

    Four distinct cat hemoplasma species are recognized worldwide. However, this is the first study to investigate the prevalence, risk factors, and hematological findings of hemoplasmas in cats from Chile. Complete blood count and 16S rRNA real-time PCR for cat hemoplasma species were performed in 384 blood samples from domestic cats in Valdivia, Chile. Among the 384 samples the species-specific prevalence was as follows: 'Candidatus Mycoplasma haemominutum' (7.8%), Mycoplasma haemofelis (4.4%), 'Candidatus Mycoplasma turicensis' (1%), 'Ca. M. haemominutum'+M. haemofelis (0.78%), 'Ca. M. haemominutum'+'Ca. M. turicensis' (0.52%), 'Ca. M. haemominutum'+'Candidatus Mycoplasma haematoparvum' (0.26%) and 'Ca. M. haemominutum'+M. haemofelis+'Ca. M. haematoparvum' (0.26%). Male sex, older age, outdoor access, and FIV status were risk factors for hemoplasmosis. Mycoplasma haemofelis-positive cats had higher mean corpuscular volume and monocyte count. Four hemoplasma species circulate in the cat population of Valdivia. 'Candidatus M. turicensis' and 'Ca. M. haematoparvum' have been reported for the first time in Chilean cats.

  14. Occurrence of canine hemotropic mycoplasmas in domestic dogs from urban and rural areas of the Valdivia Province, southern Chile.

    PubMed

    Soto, Francisco; Walker, Romina; Sepulveda, Maximiliano; Bittencourt, Pedro; Acosta-Jamett, Gerardo; Müller, Ananda

    2017-02-01

    This is the first study to investigate the occurrence, risk factors and hematological findings of hemoplasmas in dogs from Chile. Complete blood count and 16S rRNA conventional PCR for Mycoplasma spp. were performed in 278 blood samples from rural (n=139) and urban (n=139) dogs in Valdivia. Real time 16S rRNA PCR (qPCR) allowed species identification. Mycoplasma spp. occurrence was 24.8%. 'Candidatus M. haematoparvum' (CMhp) was identified in 12.2% and Mycoplasma haemocanis (Mhc) in 11.9% dogs. It was not possible to identify species in two Mycoplasma spp. samples by qPCR. Sequencing allowed identifying one of them as 'Candidatus M. turicensis' (CMt). Frequency in rural localities was higher (41.7%) than in urban (7.9%). Rural locality, maleness and older age were risk factors for hemoplasmosis. Hemoplasma-positive dogs had a higher total protein. This is the first report of Mhc, CMhp and CMt in dogs from Chile, with a high occurrence in rural localities.

  15. Reef development at Inhaca Island, Mozambique: coral communities and impacts of the 1999/2000 Southern African floods.

    PubMed

    Perry, Christopher T

    2003-03-01

    Inhaca Island, southern Mozambique, is located towards the southerly latitudinal limits of coral reef growth. Reef development is restricted to the margins of channels which dissect intertidal flats on the Maputo Bay side of the island, and to depths of around 6 m. In contrast to lower latitude reefs, reef development is therefore both spatially and bathymetrically restricted (largely due to high turbidity levels). These natural stress levels were exacerbated, via increased freshwater and sediment discharge, during the severe floods of late 1999/early 2000. Flood impacts varied but were most significant on reefs on the inner (western) side of the island where live coral cover (LCC) decreased from 60.5% (1999) to 24.0% (2001). This is attributed to freshwater-induced bleaching. Dead in situ coral cover increased from 18.6% (1999) to 51.3% (2001). Reefs on the southern tip of the island, by contrast, were relatively unaffected. It is suggested that this largely reflects a closer proximity to the open Indian Ocean which mitigated the effects of freshwater dilution.

  16. Bona Fide Evidence for Natural Vertical Transmission of Infectious Salmon Anemia Virus in Freshwater Brood Stocks of Farmed Atlantic Salmon (Salmo salar) in Southern Chile

    PubMed Central

    Ramírez, Ramón; Labra, Alvaro; Carmona, Marisela; Muñoz, Cristián

    2014-01-01

    ABSTRACT Infectious salmon anemia (ISA) is a severe disease that affects farmed Atlantic salmon (Salmo salar), causing outbreaks in seawater in most salmon-producing countries worldwide, with particular aggressiveness in southern Chile. The etiological agent of this disease is a virus belonging to the Orthomyxoviridae family, named infectious salmon anemia virus (ISAV). Although it has been suggested that this virus can be vertically transmitted, even in freshwater, there is a lack of compelling experimental evidence to confirm this. Here we demonstrate significant putative viral loads in the ovarian fluid as well as in the eggs of two brood stock female adult specimens that harbored the virus systemically but without clinical signs. The target virus corresponded to a highly polymorphic region 3 (HPR-3) variant, which is known to be virulent in seawater and responsible for recent and past outbreaks of this disease in Chile. Additionally, the virus recovered from the fluid as well as from the interior of the eggs was fully infective to a susceptible fish cell line. To our knowledge, this is the first robust evidence demonstrating mother-to-offspring vertical transmission of the infective virus on the one hand and the asymptomatic transmission of a virulent form of the virus in freshwater fish on the other hand. IMPORTANCE The robustness of the data presented here will contribute to a better understanding of the biology of the virus but most importantly will constitute a key management tool in the control of an aggressive agent constantly threatening the sustainability of the global salmon industry. PMID:24623436

  17. Multiple cardiometabolic risk factors in the Southern Cone of Latin America: a population-based study in Argentina, Chile, and Uruguay.

    PubMed

    Rubinstein, Adolfo L; Irazola, Vilma E; Calandrelli, Matias; Elorriaga, Natalia; Gutierrez, Laura; Lanas, Fernando; Manfredi, Jose A; Mores, Nora; Olivera, Hector; Poggio, Rosana; Ponzo, Jacqueline; Seron, Pamela; Chen, Chung-Shiuan; Bazzano, Lydia A; He, Jiang

    2015-03-15

    Cardiovascular disease is a major cause of death, and its mortality is increasing in Latin America. However, population-based data on cardiovascular disease risk factors are sparse in these countries. A total of 7524 men and women, aged 35 to 74 years old, were recruited between February 2010 and December 2011 from randomly selected samples in 4 cities (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay) in the Southern Cone of Latin America. Cardiovascular risk factors were measured using standard methods by trained and certified observers. Approximately 85.5% of adults ate less than five servings of fruit or vegetables per day, 35.2% engaged in low physical activity, and 29.7% currently smoked cigarettes. The prevalences of obesity, central obesity, hypertension, chronic kidney disease, dyslipidemia, diabetes, and metabolic syndrome were 35.7%, 52.9%, 40.8%, 2.0%, 58.4%, 12.4%, and 37.4%, respectively. The proportion of individuals with ≥3 cardiovascular risk factors, including low intake of fruit and vegetables, low physical activity, current cigarette smoking, obesity or central obesity, hypertension, chronic kidney disease, dyslipidemia, and diabetes, was 68.3%, and the proportion of individuals with ≥3 cardiometabolic risk factors, including obesity or central obesity, hypertension, chronic kidney disease, dyslipidemia, and diabetes, was 22.9%. Cardiovascular disease risk factors are highly prevalent in the general population in the Southern Cone of Latin America. These data suggest that national efforts on the prevention, treatment, and control of cardiovascular risk factors should be a public health priority in the Southern Cone of Latin America. Copyright © 2015. Published by Elsevier Ireland Ltd.

  18. Multiple Cardiometabolic Risk Factors in the Southern Cone of Latin America: A Population-based Study in Argentina, Chile, and Uruguay

    PubMed Central

    Rubinstein, Adolfo L.; Irazola, Vilma E.; Calandrelli, Matias; Elorriaga, Natalia; Gutierrez, Laura; Lanas, Fernando; Manfredi, Jose A.; Mores, Nora; Olivera, Hector; Poggio, Rosana; Ponzo, Jacqueline; Seron, Pamela; Chen, Chung-Shiuan; Bazzano, Lydia A.; He, Jiang

    2015-01-01

    Background Cardiovascular disease is a major cause of death, and its mortality is increasing in Latin America. However, population-based data on cardiovascular disease risk factors are sparse in these countries. Methods A total of 7,524 men and women, aged 35 to 74 years old, were recruited between February 2010 and December 2011 from randomly selected samples in 4 cities (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay) in the Southern Cone of Latin America. Cardiovascular risk factors were measured using standard methods by trained and certified observers. Results Approximately 85.5% of adults ate less than five servings of fruit or vegetables per day, 35.2% engaged in low physical activity, and 29.7% currently smoked cigarettes. The prevalences of obesity, central obesity, hypertension, chronic kidney disease, dyslipidemia, diabetes, and metabolic syndrome were 35.7%, 52.9%, 40.8%, 2.0%, 58.4%, 12.4%, and 37.4%, respectively. The proportion of individuals with ≥3 cardiovascular risk factors, including low intake of fruit and vegetables, low physical activity, current cigarette smoking, obesity or central obesity, hypertension, chronic kidney disease, dyslipidemia, and diabetes, was 68.3%, and the proportion of individual with ≥3 cardiometabolic risk factors, including obesity or central obesity, hypertension, chronic kidney disease, dyslipidemia, and diabetes, was 22.9%. Conclusions Cardiovascular disease risk factors are highly prevalent in the general population in the Southern Cone of Latin America. These data suggest that national efforts on the prevention, treatment, and control of cardiovascular risk factors should be a public health priority in the Southern Cone of Latin America. PMID:25662056

  19. Dynamics of Clinical and Environmental Vibrio parahaemolyticus Strains during Seafood-Related Summer Diarrhea Outbreaks in Southern Chile

    PubMed Central

    García, Katherine; Torres, Rafael; Uribe, Paulina; Hernández, Cristina; Rioseco, M. Luisa; Romero, Jaime; Espejo, Romilio T.

    2009-01-01

    Seafood consumption-related diarrhea became prevalent in Chile when the pandemic strain of Vibrio parahaemolyticus serotype O3:K6 reached a region in the south of Chile (Region de los Lagos) where approximately 80% of the country's seafood is produced. In spite of the large outbreaks of clinical infection, the load of V. parahaemolyticus in shellfish of this region is relatively low. The pandemic strain constitutes a small but relatively stable group of a diverse V. parahaemolyticus population, composed of at least 28 genetic groups. Outbreaks in Region de los Lagos began in 2004 and reached a peak in 2005 with 3,725 clinical cases, all associated with the pandemic strain. After 2005, reported cases steadily decreased to a total of 477 cases in 2007. At that time, 40% of the clinical cases were associated with a pandemic strain of a different serotype (O3:K59), and 27% were related to V. parahaemolyticus isolates unrelated to the pandemic strain. In the results published here, we report that in the summer of 2008, when reported cases unexpectedly increased from 477 to 1,143, 98% of the clinical cases were associated with the pandemic strain serotype O3:K6, a change from 2007. Nevertheless, in 2009, when clinical cases decreased to 441, only 64% were related to the pandemic strain; the remaining cases were related to a nonpandemic tdh- and trh-negative strain first identified in shellfish in 2006. Overall, our observations indicate that the pandemic strain has become a relatively stable subpopulation and that when the number of diarrhea cases related to the pandemic strain is low, previously undetected V. parahaemolyticus pathogenic strains become evident. PMID:19801458

  20. Dynamics of clinical and environmental Vibrio parahaemolyticus strains during seafood-related summer diarrhea outbreaks in southern Chile.

    PubMed

    García, Katherine; Torres, Rafael; Uribe, Paulina; Hernández, Cristina; Rioseco, M Luisa; Romero, Jaime; Espejo, Romilio T

    2009-12-01

    Seafood consumption-related diarrhea became prevalent in Chile when the pandemic strain of Vibrio parahaemolyticus serotype O3:K6 reached a region in the south of Chile (Region de los Lagos) where approximately 80% of the country's seafood is produced. In spite of the large outbreaks of clinical infection, the load of V. parahaemolyticus in shellfish of this region is relatively low. The pandemic strain constitutes a small but relatively stable group of a diverse V. parahaemolyticus population, composed of at least 28 genetic groups. Outbreaks in Region de los Lagos began in 2004 and reached a peak in 2005 with 3,725 clinical cases, all associated with the pandemic strain. After 2005, reported cases steadily decreased to a total of 477 cases in 2007. At that time, 40% of the clinical cases were associated with a pandemic strain of a different serotype (O3:K59), and 27% were related to V. parahaemolyticus isolates unrelated to the pandemic strain. In the results published here, we report that in the summer of 2008, when reported cases unexpectedly increased from 477 to 1,143, 98% of the clinical cases were associated with the pandemic strain serotype O3:K6, a change from 2007. Nevertheless, in 2009, when clinical cases decreased to 441, only 64% were related to the pandemic strain; the remaining cases were related to a nonpandemic tdh- and trh-negative strain first identified in shellfish in 2006. Overall, our observations indicate that the pandemic strain has become a relatively stable subpopulation and that when the number of diarrhea cases related to the pandemic strain is low, previously undetected V. parahaemolyticus pathogenic strains become evident.

  1. Helium and methane sources and fluxes of shallow submarine hydrothermal plumes near the Tokara Islands, Southern Japan

    NASA Astrophysics Data System (ADS)

    Wen, Hsin-Yi; Sano, Yuji; Takahata, Naoto; Tomonaga, Yama; Ishida, Akizumi; Tanaka, Kentaro; Kagoshima, Takanori; Shirai, Kotaro; Ishibashi, Jun-Ichiro; Yokose, Hisayoshi; Tsunogai, Urumu; Yang, Tsanyao F.

    2016-09-01

    Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys were performed during the research cruise KS-14-10 of the R/V Shinsei Maru in a region stretching from the Wakamiko Crater to the Tokara Islands. The 3He flux and methane flux in the investigated area are estimated to be (0.99–2.6) × 104 atoms/cm2/sec and 6–60 t/yr, respectively. The methane in the region of the Tokara Islands is a mix between abiotic methane similar to that found in the East Pacific Rise and thermogenic one. Methane at the Wakamiko Crater is of abiotic origin but affected by isotopic fractionation through rapid microbial oxidation. The helium isotopes suggest the presence of subduction-type mantle helium at the Wakamiko Crater, while a larger crustal component is found close to the Tokara Islands. This suggests that the Tokara Islands submarine volcanoes are a key feature of the transition zone between the volcanic front and the spreading back-arc basin.

  2. Helium and methane sources and fluxes of shallow submarine hydrothermal plumes near the Tokara Islands, Southern Japan.

    PubMed

    Wen, Hsin-Yi; Sano, Yuji; Takahata, Naoto; Tomonaga, Yama; Ishida, Akizumi; Tanaka, Kentaro; Kagoshima, Takanori; Shirai, Kotaro; Ishibashi, Jun-Ichiro; Yokose, Hisayoshi; Tsunogai, Urumu; Yang, Tsanyao F

    2016-09-27

    Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys were performed during the research cruise KS-14-10 of the R/V Shinsei Maru in a region stretching from the Wakamiko Crater to the Tokara Islands. The (3)He flux and methane flux in the investigated area are estimated to be (0.99-2.6) × 10(4) atoms/cm(2)/sec and 6-60 t/yr, respectively. The methane in the region of the Tokara Islands is a mix between abiotic methane similar to that found in the East Pacific Rise and thermogenic one. Methane at the Wakamiko Crater is of abiotic origin but affected by isotopic fractionation through rapid microbial oxidation. The helium isotopes suggest the presence of subduction-type mantle helium at the Wakamiko Crater, while a larger crustal component is found close to the Tokara Islands. This suggests that the Tokara Islands submarine volcanoes are a key feature of the transition zone between the volcanic front and the spreading back-arc basin.

  3. Helium and methane sources and fluxes of shallow submarine hydrothermal plumes near the Tokara Islands, Southern Japan

    PubMed Central

    Wen, Hsin-Yi; Sano, Yuji; Takahata, Naoto; Tomonaga, Yama; Ishida, Akizumi; Tanaka, Kentaro; Kagoshima, Takanori; Shirai, Kotaro; Ishibashi, Jun-ichiro; Yokose, Hisayoshi; Tsunogai, Urumu; Yang, Tsanyao F.

    2016-01-01

    Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys were performed during the research cruise KS-14-10 of the R/V Shinsei Maru in a region stretching from the Wakamiko Crater to the Tokara Islands. The 3He flux and methane flux in the investigated area are estimated to be (0.99–2.6) × 104 atoms/cm2/sec and 6–60 t/yr, respectively. The methane in the region of the Tokara Islands is a mix between abiotic methane similar to that found in the East Pacific Rise and thermogenic one. Methane at the Wakamiko Crater is of abiotic origin but affected by isotopic fractionation through rapid microbial oxidation. The helium isotopes suggest the presence of subduction-type mantle helium at the Wakamiko Crater, while a larger crustal component is found close to the Tokara Islands. This suggests that the Tokara Islands submarine volcanoes are a key feature of the transition zone between the volcanic front and the spreading back-arc basin. PMID:27671524

  4. Characterization of a Miocene carbonate reservoir analog in Southern Mallorca (Balearic Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Vandeginste, V.; Camoin, G.; Eisenhauer, A.; Pézard, P.; Lapointe, P.

    2009-04-01

    Carbonate reservoirs contain more than half the world's oil reserves, including highly productive reservoirs in Cretaceous and Cenozoic carbonates from the Middle East and Southeastern Asia. They are usually characterized by the complexity both of their internal architecture and of the distribution of their diagenetic fabrics which hampers crosshole correlations at various scales, and predictions regarding flow paths and volumes of fluids. Reservoir analogs can have the advantage of easier accessibility and sampling and less severe diagenetic alteration. Their study often provides information complementary to the knowledge of hydrocarbon reservoirs and it leads to a better understanding of carbonate systems, important to make better predictions on other potential reservoirs. Significant advances can be made from joint research in natural laboratories integrating outcrops and shallow boreholes, with extensive control on geophysical, geological and petrophysical parameters. The southern part of the island of Mallorca appears as a natural laboratory where a direct comparison between outcrop and shallow subsurface datasets is the objective of the current study. This region is characterized both by spectacular outcrops, especially in the Cabo Blanco area, which were previously studied [e.g. 1], and by shallow holes, 100 m deep on average, that have been drilled especially at Can Roses, Ses Pastores and Ses Sitjoles, from west to east. This geographical extension of the study area provides the opportunity to better explore and understand the Miocene carbonate complex which comprises the Llucmajor platform. This study incorporates a wide range of analytical techniques to characterize the reservoir aspects, such as conventional microscopy of thin sections, XRD analysis, isotopic carbon and oxygen analysis, isotopic strontium dating analysis, petrophysical measurements, high-resolution borehole images and CT scan data. These techniques are used to unravel the sedimentology

  5. Magnitudes and moment-duration scaling of low-frequency earthquakes beneath southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Bostock, M. G.; Thomas, A. M.; Savard, G.; Chuang, L.; Rubin, A. M.

    2015-09-01

    We employ 130 low-frequency earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from hundreds to thousands of individual LFEs, representing over 269,000 independent detections from major episodic-tremor-and-slip (ETS) events between 2003 and 2013. Template displacement waveforms for direct P and S waves at near epicentral distances are remarkably simple at many stations, approaching the zero-phase, single pulse expected for a point dislocation source in a homogeneous medium. High spatiotemporal precision of template match-filtered detections facilitates precise alignment of individual LFE detections and analysis of waveforms. Upon correction for 1-D geometrical spreading, attenuation, free surface magnification and radiation pattern, we solve a large, sparse linear system for 3-D path corrections and LFE magnitudes for all detections corresponding to a single-ETS template. The spatiotemporal distribution of magnitudes indicates that typically half the total moment release occurs within the first 12-24 h of LFE activity during an ETS episode when tidal sensitivity is low. The remainder is released in bursts over several days, particularly as spatially extensive rapid tremor reversals (RTRs), during which tidal sensitivity is high. RTRs are characterized by large-magnitude LFEs and are most strongly expressed in the updip portions of the ETS transition zone and less organized at downdip levels. LFE magnitude-frequency relations are better described by power law than exponential distributions although they exhibit very high b values ≥˜5. We examine LFE moment-duration scaling by generating templates using detections for limiting magnitude ranges (MW<1.5, MW≥2.0). LFE duration displays a weaker dependence upon moment than expected for self-similarity, suggesting that LFE asperities are limited in fault dimension and that moment variation is dominated by

  6. Ecological implications of Laurel Wilt infestation on Everglades Tree Islands, southern Florida

    USGS Publications Warehouse

    Snyder, James R.

    2014-01-01

    , laurel wilt disease also kills other native trees that are members of the laurel family, including swamp bay (Persea palustris), silk bay (Persea borbonia var. humilis), and sassafras (Sassafras albidum), as well as the economically important cultivated avocado (Persea americana) (Fraedrich and others, 2008). This paper is concerned primarily with swamp bay, an important component of Everglades tree islands.The spread of the redbay ambrosia beetle and its fungal symbiont has been very rapid, exceeding model predictions (Koch and Smith, 2008); by 2011, laurel wilt disease was found from the southern coastal plain of North Carolina to southern peninsular Florida. The first redbay ambrosia beetle was trapped in Miami-Dade County in March 2010, and laurel wilt disease was discovered in swamp bays in February 2011 and in commercial avocado groves about a year later (Kendra and others, 2013). By 2013, laurel wilt disease was seen in swamp bays throughout the southern Everglades in Everglades National Park, Big Cypress National Preserve, and Water Conservation Areas (WCAs) 3A and 3B (Rodgers and others, 2014).

  7. A remote sensing assessment of the impact of the 2010 Maule, Chile earthquake (Mw 8.8) on the volcanoes of the southern Andes

    NASA Astrophysics Data System (ADS)

    Pritchard, M. E.; Welch, M.; Jay, J.; Button, N.

    2011-12-01

    There are tantalizing, but controversial, indications that great earthquakes affect arc-wide volcanic activity. For example, analysis of historic eruptions at volcanoes of the southern Andes has shown that 3-4 eruptions were likely seismically triggered by Mw > 8 earthquakes in the Chile subduction zone -- particularly the 1906 and 1960 earthquakes (e.g., Watt et al., 2009). However, the 27 February 2010 Mw 8.8 Maule, Chile earthquake that ruptured the subduction zone between the 1960 and 1906 earthquakes does not appear to have triggered 3-4 volcanic eruptions in the same area in the 12 months after the event. In an effort to understand the relation between a large earthquake and volcanic unrest, we use a variety of satellite instruments to look for more subtle (i.e., not leading to eruption), but detectable change in thermal or deformation activity at the volcanoes of the southern Andes after the Maule earthquake and its aftershocks. For all of the volcanoes in the catalog of the Smithsonian Institution (approximately 80), we use nighttime MODIS and ASTER data to assess the thermal activity and ALOS InSAR data to characterize the surface deformation before and after the earthquake. The ALOS InSAR data are not ideal for detecting changes in deformation before and after the earthquake because of the small number of acquisitions in austral summer as well as ionospheric and tropospheric artifacts. We estimate that we could detect deformation > 5 cm/year. Similarly, the ASTER and MODIS data suffer respectively from poor temporal and spatial resolution of thermal anomalies. We update previous InSAR work that identified at least 8 areas of volcanic deformation in the southern Andes related to eruptive processes, subsidence of past lava flows, or surface uplift not associated with an eruption (Fournier et al., 2010). Of greatest interest are the two volcanic areas with the largest deformation signals between 2007-2008 (both > 15 cm/yr in the radar line of sight): Laguna

  8. Quantitative distribution and functional groups of intertidal macrofaunal assemblages in Fildes Peninsula, King George Island, South Shetland Islands, Southern Ocean.

    PubMed

    Liu, Xiaoshou; Wang, Lu; Li, Shuai; Huo, Yuanzi; He, Peimin; Zhang, Zhinan

    2015-10-15

    To evaluate spatial distribution pattern of intertidal macrofauna, quantitative investigation was performed in January to February, 2013 around Fildes Peninsula, King George Island, South Shetland Islands. A total of 34 species were identified, which were dominated by Mollusca, Annelida and Arthropoda. CLUSTER analysis showed that macrofaunal assemblages at sand-bottom sites belonged to one group, which was dominated by Lumbricillus sp. and Kidderia subquadrata. Macrofaunal assemblages at gravel-bottom sites were divided into three groups while Nacella concinna was the dominant species at most sites. The highest values of biomass and Shannon-Wiener diversity index were found in gravel sediment and the highest value of abundance was in sand sediment of eastern coast. In terms of functional group, detritivorous and planktophagous groups had the highest values of abundance and biomass, respectively. Correlation analysis showed that macrofaunal abundance and biomass had significant positive correlations with contents of sediment chlorophyll a, phaeophorbide and organic matter.

  9. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    NASA Astrophysics Data System (ADS)

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus

    2016-08-01

    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity < 32.5 and 5-10 m thick during major plume events in 2002, 2005 and 2006. Surface salinity minima are correlated with peaks in turbidy from the normalized water leaving radiance at 555 nm (nLw(555)), both representing turbid river plumes. EOF analysis reveals that major turbid plume events occurred primarily during warm phases of the ENSO and PDO, and negative phases of the AAO, when storm tracks are further north. Anomalously large turbid plumes extend long distances offshore (∼ 70-80 km), and individual plumes coalesce into a continuous plume along the coast that covers the entire continental shelf. Season-specific correlation analyses reveal an increased influence of the AAO on river plumes south of Punta Lavapié in spring-summer (negative correlation). North of this major cape, ENSO and PDO indices have a dominant influence on plumes with positive correlations with the nLw(555) signal in winter (and negative in summer). We discuss the biogeochemical implications of plume events and the importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  10. Estimating impacts of plantation forestry on plant biodiversity in southern Chile-a spatially explicit modelling approach.

    PubMed

    Braun, Andreas Christian; Koch, Barbara

    2016-10-01

    Monitoring the impacts of land-use practices is of particular importance with regard to biodiversity hotspots in developing countries. Here, conserving the high level of unique biodiversity is challenged by limited possibilities for data collection on site. Especially for such scenarios, assisting biodiversity assessments by remote sensing has proven useful. Remote sensing techniques can be applied to interpolate between biodiversity assessments taken in situ. Through this approach, estimates of biodiversity for entire landscapes can be produced, relating land-use intensity to biodiversity conditions. Such maps are a valuable basis for developing biodiversity conservation plans. Several approaches have been published so far to interpolate local biodiversity assessments in remote sensing data. In the following, a new approach is proposed. Instead of inferring biodiversity using environmental variables or the variability of spectral values, a hypothesis-based approach is applied. Empirical knowledge about biodiversity in relation to land-use is formalized and applied as ascription rules for image data. The method is exemplified for a large study site (over 67,000 km(2)) in central Chile, where forest industry heavily impacts plant diversity. The proposed approach yields a coefficient of correlation of 0.73 and produces a convincing estimate of regional biodiversity. The framework is broad enough to be applied to other study sites.

  11. Household Characteristics Associated with Rodent Presence and Leptospira Infection in Rural and Urban Communities from Southern Chile

    PubMed Central

    Muñoz-Zanzi, Claudia; Mason, Meghan; Encina, Carolina; Gonzalez, Marcelo; Berg, Sergey

    2014-01-01

    Rodents are well-recognized reservoirs of Leptospira, contributing to its maintenance in endemic areas and playing a role in the public health risk associated with the infection. This study sought to provide some insights into rodent populations from Chile and their Leptospira carriage. In total, 393 rodents were trapped in 177 households. Higher rodent counts were associated with year 2 of the study, rainfall, and number of rodent signs. There was an inverse correlation with the number of cats. The number of rodents was higher in villages compared with slums (rate ratio = 3.23) but modified by average household age. Eighty rodents (20.4%) tested positive for Leptospira: 19.7% on the farms, 25.9% in villages, and 12.3% in the slums. Prevalence was 22.5% in Mus musculus, 20.7% in Rattus rattus, 21.1% in wild rodents, and 10.3% in R. norvegicus. Seasonal and temporal effects were the major determinants of Leptospira infection in rodent populations. PMID:24445209

  12. Source Rupture Models and Tsunami Simulations of Destructive October 28, 2012 Queen Charlotte Islands, British Columbia (Mw: 7.8) and September 16, 2015 Illapel, Chile (Mw: 8.3) Earthquakes

    NASA Astrophysics Data System (ADS)

    Taymaz, Tuncay; Yolsal-Çevikbilen, Seda; Ulutaş, Ergin

    2016-04-01

    The finite-fault source rupture models and numerical simulations of tsunami waves generated by 28 October 2012 Queen Charlotte Islands (Mw: 7.8), and 16 September 2015 Illapel-Chile (Mw: 8.3) earthquakes are presented. These subduction zone earthquakes have reverse faulting mechanisms with small amount of strike-slip components which clearly reflect the characteristics of convergence zones. The finite-fault slip models of the 2012 Queen Charlotte and 2015 Chile earthquakes are estimated from a back-projection method that uses teleseismic P- waveforms to integrate the direct P-phase with reflected phases from structural discontinuities near the source. Non-uniform rupture models of the fault plane, which are obtained from the finite fault modeling, are used in order to describe the vertical displacement on seabed. In general, the vertical displacement of water surface was considered to be the same as ocean bottom displacement, and it is assumed to be responsible for the initial water surface deformation gives rise to occurrence of tsunami waves. In this study, it was calculated by using the elastic dislocation algorithm. The results of numerical tsunami simulations are compared with tide gauges and Deep-ocean Assessment and Reporting of Tsunami (DART) buoy records. De-tiding, de-trending, low-pass and high-pass filters were applied to detect tsunami waves in deep ocean sensors and tide gauge records. As an example, the observed records and results of simulations showed that the 2012 Queen Charlotte Islands earthquake generated about 1 meter tsunami-waves in Maui and Hilo (Hawaii), 5 hours and 30 minutes after the earthquake. Furthermore, the calculated amplitudes and time series of the tsunami waves of the recent 2015 Illapel (Chile) earthquake are exhibiting good agreement with the records of tide and DART gauges except at stations Valparaiso and Pichidangui (Chile). This project is supported by The Scientific and Technological Research Council of Turkey (TUBITAK

  13. Fine-scale movements of rural free-ranging dogs in conservation areas in the temperate rainforest of the coastal range of southern Chile

    USGS Publications Warehouse

    Sepulveda, Maximiliano; Pelican, Katherine; Cross, Paul C.; Eguren, Antonieta; Singer, Randall S.

    2015-01-01

    Domestic dogs can play a variety of important roles for farmers. However, when in proximity to conservation areas, the presence of rural free-ranging dogs can be problematic due to the potential for predation of, competition with, or transmission of infectious disease to local threatened fauna. We used a frequent location radio tracking technology to study rural free-ranging dog movements and habitat use into sensitive conservation habitats. To achieve a better understanding of foray behaviors in dogs we monitored dogs (n = 14) in rural households located in an isolated area between the Valdivian Coastal Reserve and the Alerce Costero National Park in southern Chile. Dogs were mostly located near households (<200 m) but exhibited a diurnal pattern of directed excursions (forays) away from their home locations. Dogs spent, on average, 5.3% of their time in forays with average per dog foray distances from the house ranging 0.5–1.9 km (maximum distance detected 4.3 km). Foraying behavior was positively associated with pasture habitat compared to forest habitat including protected lands. Foraying dogs rarely used forest habitat and, when entered, trails and/or roads were selected for movement. Our study provides important information about how dogs interact in a fine-scale with wildlife habitat, and, in particular, protected lands, providing insight into how dog behavior might drive wildlife interactions, and, in turn, how an understanding of dog behavior can be used to manage these interactions.

  14. Nematode parasites of the digestive tract in Neotropic cormorant chicks (Phalacrocorax brasilianus) from the River Cruces Ramsar site in southern Chile.

    PubMed

    Torres, Patricio; Ortega, Jorge; Schlatter, Roberto

    2005-09-01

    The neotropic cormorant (Phalacrocorax brasilianus) breeding colony of the Rio Cruces Nature Sanctuary and Ramsar site was surveyed for nematode parasites in southern Chile. Moribund chicks (n=128) of different ages were inspected for anchored nematodes using complete guts. We tested if chicks harbored the same parasites as the adults feeding them. Besides the known Contracaecum rudolphii, third or fourth stage larvae of Pseudoterranova sp. and Anisakis (type I and II) were obtained in this waterbird species for the first time. Most parasites were located in the stomach and C. rudolphii was the dominant species. The prevalence and mean intensity of C. rudolphii infections and the prevalence of Anisakis type I larvae were significantly less (P<0.05) in the youngest age group of the birds. The prevalence of Pseudoterranova sp. larvae infection was similar among birds of different age. The mean intensity with Pseudoterranova sp. was significantly less (P<0.05) in younger birds and in Anisakis type I it was similar in different age groups.

  15. Using stated preference methods to design cost-effective subsidy programs to induce technology adoption: an application to a stove program in southern Chile.

    PubMed

    Gómez, Walter; Salgado, Hugo; Vásquez, Felipe; Chávez, Carlos

    2014-01-01

    We study the design of an economic incentive based program - a subsidy - to induce adoption of more efficient technology in a pollution reduction program in southern Chile. Stated preferences methods, contingent valuation (CV), and choice experiment (CE) are used to estimate the probability of adoption and the willingness to share the cost of a new technology by a household. The cost-effectiveness property of different subsidy schemes is explored numerically for different regulatory objectives. Our results suggest that households are willing to participate in voluntary programs and to contribute by paying a share of the cost of adopting more efficient technologies. We find that attributes of the existing and the new technology, beyond the price, are relevant determinant factors of the participation decision and payment. Limited access to credit markets for low income families can be a major barrier for an effective implementation of these types of programs. Variations in the design of the subsidy and on the regulator's objective and constraints can have significant impact on the level and the cost of reduction of aggregate emissions achieved. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Resistivity distribution from mid-crustal conductor to near-surface across the 1200 km long Liquiñe-Ofqui Fault System, southern Chile

    NASA Astrophysics Data System (ADS)

    Held, Sebastian; Schill, Eva; Pavez, Maximiliano; Díaz, Daniel; Muñoz, Gerard; Morata, Diego; Kohl, Thomas

    2016-12-01

    Mid-crustal conductors are a common phenomenon in magnetotelluric studies. In the Andean Cordillera of southern Chile, they appear to concentrate along major fault zones. A high-resolution, broad-band magnetotelluric survey including 31 stations has been carried out along two profiles perpendicular to (1) the Liquiñe-Ofqui Fault Systems (LOFS) and (2) the Villarrica-Quetrupillán-Lanín volcanic lineament running parallel to the Mocha-Villarrica Fault Zone (MVFZ). The survey aimed at tracing one of the known conductors from mid-crustal depth to near-surface along these faults. Directionality and dimensionality were analysed using tensor decomposition. Phase tensors and induction arrows reveal two major geoelectric strike directions following the strike of LOFS and MVFZ. 2-D inversion shows low resistivity zones along both fault systems down to a depth of >10 km, where the brittle-ductile transition is expected. Along the LOFS, the two anomalies are linked to (1) Lake Caburgua, where the LOFS broadens to about 2 km of lateral extension and seems to represent a pull-apart structure, and (2) the intersection with the Villarrica-Quetrupillán-Lanín volcanic lineament, where seismic activity was observed during the latest eruption in March 2015. A connection of the mid-crustal conductor to the ESE-WNW-striking fault zones is indicated from the presented data.

  17. Conceptual PHES-system models of the Aysén watershed and fjord (Southern Chile): testing a brainstorming strategy.

    PubMed

    Marín, Víctor H; Delgado, Luisa E; Bachmann, Pamela

    2008-09-01

    The use of brainstorming techniques for the generation of conceptual models, as the basis for the integrated management of physical-ecological-social systems (PHES-systems) is tested and discussed. The methodology is applied in the analysis of the Aysén fjord and watershed (Southern Chilean Coast). Results show that the proposed methods can be adequately used in management scenarios characterized by highly hierarchical, experts/non-experts membership.

  18. Chemical and isotopic investigations of fumarolic gases from Ischia island (southern Italy): Evidences of magmatic and crustal contribution

    NASA Astrophysics Data System (ADS)

    Tedesco, Dario

    1996-12-01

    Chemical and isotopic investigations have been carried out on subaerial and submarine fumarolic fluids on the island of Ischia, Gulf of Napoli (Southern Italy). Chemical analyses of gases from the hottest fumarole (117 °C) located on Mount Epomeo show a typical geothermal composition. Thermodynamic computations indicate a feeding source temperature of Mt. Epomeo ranging from 300 to 500 °C. Isotopic compositions suggest that the island is divided into two parts (East and West). Fumarole gases on the west side of the island indicate a magmatic source with small crustal contamination, and are characterized by carbon isotopic data similar to MORB (δ 13C ranging from -3.5 to -5.11%.) with about 50% of the helium having a magmatic origin (3.6-3.7 {R}/{R a}). Fumaroles located on the east side of the island have carbon isotopic data ranging from +0.45 to -0.76%. and a lower helium isotopic ratio (from 2.09 to 2.89 {R}/{R a}). The east fumaroles seem to be fed by fluids deriving from a reservoir located in or close to a carbonatic source in the crust.

  19. Fine-scale population genetic structure of a wildlife disease vector: The southern house mosquito on the island of Hawaii

    USGS Publications Warehouse

    Keyghobadi, N.; LaPointe, D.; Fleischer, R.C.; Fonseca, D.M.

    2006-01-01

    The southern house mosquito, Culex quinquefasciatus, is a widespread tropical and subtropical disease vector. In the Hawaiian Islands, where it was introduced accidentally almost two centuries ago, it is considered the primary vector of avian malaria and pox. Avian malaria in particular has contributed to the extinction and endangerment of Hawaii's native avifauna, and has altered the altitudinal distribution of native bird populations. We examined the population genetic structure of Cx. quinquefasciatus on the island of Hawaii at a smaller spatial scale than has previously been attempted, with particular emphasis on the effects of elevation on population genetic structure. We found significant genetic differentiation among populations and patterns of isolation by distance within the island. Elevation per se did not have a limiting effect on gene flow; however, there was significantly lower genetic diversity among populations at mid elevations compared to those at low elevations. A recent sample taken from just above the predicted upper altitudinal distribution of Cx. quinquefasciatus on the island of Hawaii was confirmed as being a temporary summer population and appeared to consist of individuals from more than one source population. Our results indicate effects of elevation gradients on genetic structure that are consistent with known effects of elevation on population dynamics of this disease vector. ?? 2006 The Authors.

  20. Salt-water encroachment in southern Nassau and southeastern Queens Counties, Long Island, New York

    USGS Publications Warehouse

    Lusczynski, N.J.; Swarzenski, Wolfgang V.

    1966-01-01

    deposits. It extends from the seaward areas inland about 2 miles into Island Park. The deep wedge extends into southeastern Queens County and southern Nassau County principally in the deeper parts of the Magothy (?) Formation and in the underlying clay member of the Raritan Formation. The leading edge of the deep wedge is at the base of the Magothy (?) Formation. This edge is apparently at the shoreline east of Lido Beach and extends inland about 4 miles to Woodmere and about 7 miles to South Ozone Park. Zones of diffusion as much as 6 miles wide and about 500 feet thick were delineated in the frontal part of the salty-water wedges. These thick and broad zones of diffusion were probably formed during the past 1,000 or more years in heterogeneous unconsolidated deposits by long- and short-term changes in sea level and in fresh-water outflow to the sea and by dispersion caused by the movements of the water and its salt mass. Changes in sea level and fresh-water outflow together produced appreciable advances and recessions of the salt-water front. The chemical compositions of the diffused water in all wedges are modified to some extent by base exchange and other physical and chemical processes and also by diffusion. The intermediate wedge of salty water is moving landward at a rate of less than 20 feet a year in the vicinity of Island Park and, thus, has moved less than 1,000 feet since 1900. The leading edge of the deep wedge has advanced landward at about 300 feet a :ear in Woodmere in southwestern Nassau County and about 160 feet a year at South Ozone Park in southeastern Queens County, principally under the influence of local withdrawals near the toe of the wedge. Between Hewlett and Lido Beach, the deep wedge is moving inland at the rate of about 10 feet a year under the influence of regional withdrawals in inland areas. Regional encroachment of the deep wedge is apparently retarded appreciably by cyclic flow, that is, by the return seaward in the upper

  1. Morphostructure at the junction between the Beata ridge and the Greater Antilles island arc (offshore Hispaniola southern slope)

    NASA Astrophysics Data System (ADS)

    Granja Bruña, J. L.; Carbó-Gorosabel, A.; Llanes Estrada, P.; Muñoz-Martín, A.; ten Brink, U. S.; Gómez Ballesteros, M.; Druet, M.; Pazos, A.

    2014-03-01

    Oblique convergence between the Caribbean plate's interior and the inactive Greater Antilles island arc has resulted in the collision and impingement of the thickened crust of the Beata ridge into southern Hispaniola Island. Deformation resulting from this convergence changes from a low-angle southward-verging thrust south of eastern Hispaniola, to collision and uplift in south-central Hispaniola, and to left-lateral transpression along the Southern peninsula of Haiti in western Hispaniola. Using new swath bathymetry and a dense seismic reflection grid, we mapped the morphological, structural and sedimentological elements of offshore southern Hispaniola. We have identified four morphotectonic provinces: the Dominican sub-basin, the Muertos margin, the Beata ridge and the Haiti sub-basin. The lower slope of the Muertos margin is occupied by the active Muertos thrust belt, which includes several active out-of-sequence thrust faults that, were they to rupture along their entire length, could generate large-magnitude earthquakes. The interaction of the thrust belt with the Beata ridge yields a huge recess and the imbricate system disappears. The upper slope of the Muertos margin shows thick slope deposits where the extensional tectonics and slumping processes predominate. The northern Beata ridge consists of an asymmetrically uplifted and faulted block of oceanic crust. Our results suggest that the shallower structure and morphology of the northern Beata ridge can be mainly explained by a mechanism of extensional unloading from the Upper Cretaceous onward that is still active residually along the summit of the ridge. The tectonic models for the northern Beata ridge involving active reverse strike-slip faults and transpression caused by the oblique convergence between the Beata ridge and the island arc are not supported by the structural interpretation. The eastern Bahoruco slope an old normal fault that acts as a passive tear fault accommodating the sharp along

  2. Change in the length of the southern section of the Chandeleur Islands oil berm, January 13, 2011, through September 3, 2012

    USGS Publications Warehouse

    Plant, Nathaniel G.; Guy, Kristy K.

    2014-01-01

    On April 20, 2010, an explosion on the Deepwater Horizon oil rig drilling at the Macondo Prospect site in the Gulf of Mexico resulted in a marine oil spill that continued to flow through July 15, 2010. One of the affected areas was the Breton National Wildlife Refuge, which consists of a chain of low-lying islands, including Breton Island and the Chandeleur Islands, and their surrounding waters. The island chain is located approximately 115–150 kilometers (km) north-northwest of the spill site. A sand berm was constructed seaward of, and on, the island chain. Construction began at the northern end of Chandeleur Islands in June 2010 and ended in April 2011 after 14 km of berm had been constructed. The berm consisted of three distinct sections based on where the berm was placed relative to the islands. The northern section of the berm was built in open water on a submerged portion of the Chandeleur Islands platform. The middle section was built approximately 70–90 meters (m) seaward of the Chandeleur Islands. The southern section was built on the islands’ beaches. Repeated Landsat and SPOT satellite imagery and airborne light detection and ranging (lidar) were used to observe the disintegration of the berm over time. The methods used to analyze the remotely sensed data and the resulting, derived data for the southern section are reported.

  3. Farm-level reproduction number during an epidemic of infectious salmon anemia virus in southern Chile in 2007-2009.

    PubMed

    Mardones, F O; Perez, A M; Valdes-Donoso, P; Carpenter, T E

    2011-12-01

    An epidemic of infectious salmon anemia virus (ISAV) has greatly impacted salmon production in Chile with devastating social and economic consequences. The epidemic is analyzed here and is likely the largest ISAV outbreak reported affecting one of the most productive regions for salmon farming activities in the world. After re-emerging in 2007, ISAV rapidly expanded the following two years, both in magnitude and geographic range, affecting about 65% and 50% of salmon farms located at the 10th and 11th regions of Chile, respectively. A useful metric for the control of infectious diseases that quantifies the progression of an epidemic is the reproduction number at the farm level (R(f)), which describes the mean number of secondary cases generated by an infectious farm. The parameter in this study was estimated for individual farms (R(fi)), specific phases (R(tf)), and for the entire epidemic (R(f)) by using several analytical approaches based on the characterization of the epidemic curves for the two regions. For the initial spread and the epidemic growth phase, initial and intrinsic growth rates were used to estimate R(tf). In addition, two approaches (epidemic final size and nearest neighbor analyses) were used to obtain an individual (R(fi)) and overall estimate of R(f) for the complete epidemic. In general, two distinct regional patterns of spread were identified. In the 10th region, after an explosive initial spread of ISAV in which R(tf) reached 12.0-16.9, a smaller epidemic growth of 1.6≤R(tf)≥2.5 and a final burnout with R(tf)<1 were observed. For the 11th region, R(tf) only reached 2.4 during the initial spread phase, ranged from 1.6≤R(tf)≥4.4 during the epidemic growth phases and ended when R(tf) was <1.0. The epidemic was characterized by clustering of ISAV 'superspreaders' farms i.e., farms with statistically significantly (P<0.047) higher R(fi) values. Distances between pairs of infected farms were statistically significantly (P=0.003) shorter in

  4. Magma Genesis of Sakurajima, the Quaternary post- Aira caldera volcano, southern Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Suzuki, J.; Yoshikawa, M.; Kobayashi, T.; Miki, D.; Takemura, K.

    2012-12-01

    Sakurajima volcano is the Quaternary post-caldera volcano of Aira caldera, which was caused by the eruption of huge amount of silicic pyroclastics, situated on Ryukyu arc, southern Kyushu Island, Japan. This volcano is quite active, so it can be considered that the preparation of next caldera-forming eruption with huge amount of silicic magma is proceeding. It is, therefore, expected that the investigation of magma genesis of Sakurajima volcano give us information for the mechanism generating huge amount of silicic magma, which cause the caldera formation. We analyzed major and trace elements with Sr, Nd and Pb isotopic compositions of volcanic rocks from Sakurajima volcano. We sampled (ol) - opx - cpx - pl andesite and dacite from almost all the volcanic units defined by Fukuyama and Ono (1981). In addition to Sakurajima samples, we also studied basaltic rocks erupted at pre-caldera stage of the Aira caldera to estimate the primary magma of Sakurajima volcano. Major and trace element variations generally show linear trends on the Harker diagrams, with the exception of P2O5 and TiO2. Based on the trend of P2O5 vs.SiO2, we divided studied samples low-P (P2O5 < 0.15 wt. %) and high-P (P2O5 > 0.15 wt. %) groups and these groups also display two distinct trends on TiO2-SiO2 diagram. The composition of trace elements shows typical island arc character as depletion of Nb and enrichments of Rb, K and Pb, suggesting addition of aqueous fluids to the mantle wedge. The Zr and Nb concentrations make a liner trend (Zr/Nb = 27) and this trend across from tend of MORB (Zr/Nb = 35) to that of crustal materials (Zr/Nb=17). The Sr, Nd and Pb isotopic compositions broadly plot to on the mixing curve connecting MORB-type mantle and sediments of the Philippine Sea Plate, indicating that the primary magma was generated by partial melting of MORB-type mantle wedge, which was hydrated with fluids derived from the subducted Philippine Sea sediments. But we found that our data plot apart

  5. Modelling a strike-slip fault system affecting porous carbonates in Favignana Island (Sicily, southern Italy)

    NASA Astrophysics Data System (ADS)

    Cilona, A.; Tondi, E.; Agosta, F.; Johnson, G.; Shackleton, R.

    2012-12-01

    Investigating the deformation processes as well as the characteristics and distribution of their end-products is a crucial issue to improve geo-fluid exploitation in carbonate reservoirs (≈50% of natural geo-fluids). Indeed, besides the primary controls on the petrophysical properties of limestones, which are due to nature and organization/shape of the constituent elements (i.e. grains, pores, cement, clay minerals), both containment and migration of fluids in these rocks are influenced by fault zones and fractures. In this contribution we integrate quantitative structural analysis and numerical modelling approaches aiming at testing a new workflow useful to create a 3D discrete fracture network (DFN) model of a reservoir starting from outcrop data collected in Favignana Island (Sicily, southern Italy). The presence of several quarries in the Island provides 3D exposures of ≈25 m-thick Lower-Pleistocene high-porosity grainstones crosscut by two conjugate sets of strike-slip faults. This fault system, documented by Tondi et al. (2012), is comprised of three types of structure: single compactive shear bands (CSB); zones of bands (ZB); and, faults. CSBs are narrow tabular features with porosity less than the surrounding host rocks, and have thicknesses and displacements on the order of a few mm. The growth process for these structures involves localizing further deformation within zones of closely-spaced CSBs and, possibly, along continuous slip surfaces within fault rocks overprinting older ZBs. The transitions from one growth step to another are recorded by different values of the dimensional parameters (i.e. length, thickness and displacement) for the structures. These transitions are also reflected by the ratios and distributions of the dimensional parameters. The DFN model was built by means of the Fracture Modelling module of the commercial software package Move from Midland Valley©. The analysis of an aerial photo was performed firstly to delimit the

  6. Expanding Geophysical and Geochemical Investigation of Causes of Extraordinary Unrest at the Laguna del Maule (Rhyolitic) Volcanic Field, Southern Andes, Chile

    NASA Astrophysics Data System (ADS)

    Singer, B. S.

    2014-12-01

    The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007 the crust here has been inflating at an astonishing rate of 25 cm/yr. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ~20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. Swarms of volcano-tectonic and long period earthquakes, mostly of M < 2, have occurred beneath the most recent rhyolite coulees on the southwestern and southern margins of the 20 km diameter ring of silicic vents. With support from the US NSF and the Chilean government (SERNAGEOMIN and OVDAS) we are seizing the unique opportunity to investigate, over the next 5 years, the dynamics of this large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively underway. This collaboration involves scientists and students at: University of Wisconsin-Madison, Georgia Tech, Cornell, University of Alberta, Simon Fraser University, University of Chile-Santiago, CONICET/University of San Juan-Argentina, Nanyang Technological University-Singapore, SERNAGEOMIN, OVDAS, USGS, and SEGEMAR-Argentina. Team members will be introduced in this presentation. Our approach includes augmenting the OVDAS array of 6 permanent seisic stations with 40 additional instruments to conduct tomographic, receiver function and ambient noise studies. We continue to collect 4-D gravity data from 37 stations. Surface deformation is monitored via cGPS at 5 permanent receivers and InSAR data. A magnetotelluric survey across the Andes at 36o S is planned. Geochemical studies include mineral zoning and U-Th disequilibrium of zircons to constrain the timing of magma intrusion and

  7. Ash storms: impacts of wind-remobilised volcanic ash on rural communities and agriculture following the 1991 Hudson eruption, southern Patagonia, Chile

    NASA Astrophysics Data System (ADS)

    Wilson, T. M.; Cole, J. W.; Stewart, C.; Cronin, S. J.; Johnston, D. M.

    2011-04-01

    Tephra fall from the August 1991 eruption of Volcán Hudson affected some 100,000 km2 of Patagonia and was almost immediately reworked by strong winds, creating billowing clouds of remobilised ash, or `ash storms'. The immediate impacts on agriculture and rural communities were severe, but were then greatly exacerbated by continuing ash storms. This paper describes the findings of a 3-week study tour of the diverse environments of southern Patagonia affected by ash storms, with an emphasis on determining the impacts of repeated ash storms on agriculture and local practices that were developed in an attempt to mitigate these impacts. Ash storms produce similar effects to initial tephra eruptions, prolonged for considerable periods. These have included the burial of farmland under dune deposits, abrasion of vegetation and contamination of feed supplies with fine ash. These impacts can then cause problems for grazing animals such as starvation, severe tooth abrasion, gastrointestinal problems, corneal abrasion and blindness, and exhaustion if sheep fleeces become laden with ash. In addition, ash storms have led to exacerbated soil erosion, human health impacts, increased cleanup requirements, sedimentation in irrigation canals, and disruption of aviation and land transport. Ash deposits were naturally stabilised most rapidly in areas with high rainfall (>1,500 mm/year) through compaction and enhanced vegetation growth. Stabilisation was slowest in windy, semi-arid regions. Destruction of vegetation and suppression of regrowth by heavy tephra fall (>100 mm) hindered the stabilisation of deposits for years, and reduced the surface friction which increased wind erosivity. Stabilisation of tephra deposits was improved by intensive tillage, use of windbreaks and where there was dense and taller vegetative cover. Long-term drought and the impracticality of mixing ash deposits with soil by tillage on large farms was a barrier to stabilising deposits and, in turn

  8. Nitrogen excretion by copepods and its contribution to the ammonium oxidizing activity in the upwelling zone off central-southern Chile (36°S)

    NASA Astrophysics Data System (ADS)

    Valdes, V.; Escribano, R.; Fernandez, C.; Molina, V.

    2016-02-01

    Zooplankton play a pivotal role in the nitrogen cycle by sustaining phytoplankton and heterotrophic bacterial growth through N excretion. This biogeochemical interaction between microbial community and zooplankton has been poorly studied in the ocean. In this work we explored the interaction between the nitrogen compounds excreted by dominant copepods in the upwelling zone off central Chile and the activity of ammonium oxidizing microbial community. For doing so, two experiments were conducted in May and early September 2010 off Concepción (36°S) in central-southern Chile upon non-upwelling condition. Among organic and inorganic nitrogen compounds excreted by copepods (NH4+, DON, NO3- and NO2-), DON was the most abundant. In the first experiment, DON excretion rate was <0.6 μmol L-1 h-1 in the first hours of incubation, while in the second experiment we found values of 0.9 μmol L-1 h-1 in the last hour of incubation. NH4+ excretion rates were lower than those of DON, with values ca. 0.02 and < 0.4 μmol L-1 h-1 in autumn and winter, respectively. When assessing the response of microbial ammonium oxidizing groups to the input of these excreted products, it was found that NH4+ was significantly consumed in the first four hours of incubation in the autumn experiment, while bacterioplankton abundance incremented to 8 x105 to 1.2 x106 cells mL-1 after 6 hours. The activity of AOB and AOA amoA transcript copies increased from 1,539 to 5,669 copies mL-1 and 1,510 a 3,763 copies mL-1, respectively. In the second experiment, NH4+ showed complete consumption in the first two hours of incubation and specific groups of AOA and AOB transcript were below <10,000 copies mL-1. Our findings confirm, that NH4+ is not the main compound excreted by copepods, and this can be directly used by bacterioplankton and AOB followed by AOA response to available NH4+. Both are able to utilize a large proportion of ammonium excreted by the copepods during austral autumn and winter.

  9. Magnitudes and Moment-Duration Scaling of Low-Frequency Earthquakes Beneath Southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Bostock, M. G.; Thomas, A.; Rubin, A. M.; Savard, G.; Chuang, L. Y.

    2015-12-01

    We employ 130 low-frequency-earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from 100's to 1000's of individual LFEs, representing over 300,000 independent detections from major episodic-tremor-and- slip (ETS) events between 2003 and 2013. Template displacement waveforms for direct P- and S-waves at near epicentral distances are remarkably simple at many stations, approaching the zero-phase, single pulse expected for a point dislocation source in a homogeneous medium. High spatio-temporal precision of template match-filtered detections facilitates precise alignment of individual LFE detections and analysis of waveforms. Upon correction for 1-D geometrical spreading, attenuation, free-surface magnification and radiation pattern, we solve a large, sparse linear system for 3-D path corrections and LFE magnitudes for all detections corresponding to a single ETS template. The spatio-temporal distribution of magnitudes indicates that typically half the total moment release occurs within the first 12-24 hours of LFE activity during an ETS episode when tidal sensitity is low. The remainder is released in bursts over several days, particularly as spatially extensive RTRs, during which tidal sensitivity is high. RTR's are characterized by large magnitude LFEs, and are most strongly expressed in the updip portions of the ETS transition zone and less organized at downdip levels. LFE magnitude-frequency relations are better described by power-law than exponential distributions although they exhibit very high b-values ≥ 6. We examine LFE moment-duration scaling by generating templates using detections for limiting magnitude ranges MW<1.5, MW≥ 2.0. LFE duration displays a weaker dependence upon moment than expected for self-similarity, suggesting that LFE asperities are limited in dimension and that moment variation is dominated by slip. This behaviour implies

  10. Hydrogeology and Simulated Ground-Water Flow in the Salt Pond Region of Southern Rhode Island

    USGS Publications Warehouse

    Masterson, John P.; Sorenson, Jason R.; Stone, Janet R.; Moran, S. Bradley; Hougham, Andrea

    2007-01-01

    The Salt Pond region of southern Rhode Island extends from Westerly to Narragansett Bay and forms the natural boundary between the Atlantic Ocean and the shallow, highly permeable freshwater aquifer of the South Coastal Basin. Large inputs of fresh ground water coupled with the low flushing rates to the open ocean make the salt ponds particularly susceptible to eutrophication and bacterial contamination. Ground-water discharge to the salt ponds is an important though poorly quantified source of contaminants, such as dissolved nutrients. A ground-water-flow model was developed and used to delineate the watersheds to the salt ponds, including the areas that contribute ground water directly to the ponds and the areas that contribute ground water to streams that flow into ponds. The model also was used to calculate ground-water fluxes to these coastal areas for long-term average conditions. As part of the modeling analysis, adjustments were made to model input parameters to assess potential uncertainties in model-calculated watershed delineations and in ground-water discharge to the salt ponds. The results of the simulations indicate that flow to the salt ponds is affected primarily by the ease with which water is transmitted through a glacial moraine deposit near the regional ground-water divide, and by the specified recharge rate used in the model simulations. The distribution of the total freshwater flow between direct ground-water discharge and ground-water-derived surface-water (streamflow) discharge to the salt ponds is affected primarily by simulated stream characteristics, including the streambed-aquifer connection and the stream stage. The simulated position of the ground-water divide and, therefore, the model-calculated watershed delineations for the salt ponds, were affected only by changes in the transmissivity of the glacial moraine. Selected changes in other simulated hydraulic parameters had substantial effects on total freshwater discharge and the

  11. Studies on the chironomid midges (Diptera, Chironomidae) of the Nansei Islands, southern Japan.

    PubMed

    Sasa, M

    1990-06-01

    The Nansei Islands are located in the subtropical zone of the western Pacific Ocean between Kyushu and Taiwan, and are composed of the two main island groups, the Amami and the Ryukyu Archipelagoes. This area has been known for the presence of a number of indigenous animal species. Prior to the present studies, collections of the chironomids mainly in the urban areas of the three main islands of the Ryukyus were carried out by Sasa and Hasegawa, and a total of 42 species, including 25 new species, were recorded. Additional collections of the chironomids mainly in the mountainous areas of this region were carried out by the present author during 1988 and 1989, and a total of 26 species (including 12 new species) were recorded from Amami Island, and a total of 27 species (including 10 new species) were recorded from the Ryukyu Islands. Eight species among them, including 3 new species, were common to the two archipelagos.

  12. Temporal variability in the physico-biological environment of the Prince Edward Islands (Southern Ocean)

    NASA Astrophysics Data System (ADS)

    Pakhomov, E. A.; Froneman, P. W.; Ansorge, I. J.; Lutjeharms, J. R. E.

    2000-09-01

    Oceanographic environment, chlorophyll- a (chl-a), plankton composition and spatial dynamics were investigated during two large-scale surveys conducted in April/May 1989 and 1997 within the Antarctic Polar Front Zone (APFZ) around the Prince Edward Islands. On both occasions, substantial disturbances in the flow pattern of the Antarctic Circumpolar Current (ACC) were demonstrated particularly downstream of the islands. In this region, enhanced cross frontal and zonal mixing were generated by the intrusion of foreign water masses from outside the APFZ. This may have been promoted by the differences in the flow intensity of the ACC in the vicinity of the islands which is affected by the Subantarctic Front (SAF) location near the island plateau. Distribution of chl-a was generally uniform throughout both surveys with values ranging from 0.1 to 0.2 and from 0.2 to 0.3 mg m -3 during 1989 and 1997, respectively. Although a single phytoplankon community was identified during both surveys, quantitative distribution of the surface phytoplankton showed a good consistency with spatial patterns of water masses. Community structure and distribution of meso- and macrozooplankton/micronekton confirmed that extensive cross-frontal mixing occurred in the downstream region of the islands. While no substantial differences between the inter-island and offshore assemblages of mesozooplankton were found, a distinct inter-island macroplankton community was identified. Zooplankton community structure clearly indicated the intrusion of subtropical species into the region during the 1997 survey. The extent of modifications in the APFZ planktonic realms in the vicinity of the Prince Edward Islands may be influenced by the effect of the flow regime, in particular by the speed at which the incident current, the ACC, approaches and interacts with the island group.

  13. Scale of human mobility in the southern Andes (Argentina and Chile): A new framework based on strontium isotopes.

    PubMed

    Barberena, Ramiro; Durán, Víctor A; Novellino, Paula; Winocur, Diego; Benítez, Anahí; Tessone, Augusto; Quiroga, María N; Marsh, Erik J; Gasco, Alejandra; Cortegoso, Valeria; Lucero, Gustavo; Llano, Carina; Knudson, Kelly J

    2017-10-01

    The goal of this article is to assess the scale of human paleomobility and ecological complementarity between the lowlands and highlands in the southern Andes during the last 2,300 years. By providing isotope results for human bone and teeth samples, we assess a hypothesis of "high residential mobility" suggested on the basis of oxygen isotopes from human remains. We develop an isotopic assessment of human mobility in a mountain landscape combining strontium and oxygen isotopes. We analyze bone and teeth samples as an approach to life-history changes in spatial residence. Human samples from the main geological units and periods within the last two millennia are selected. We present a framework for the analysis of bioavailable strontium based on the combination of the geological data with isotope results for rodent samples. The (87) Sr/(86) Sr values from human samples indicate residential stability within geological regions along life history. When comparing strontium and oxygen values for the same human samples, we record a divergent pattern: while δ(18) O values for samples from distant regions overlap widely, there are important differences in (87) Sr/(86) Sr values. Despite the large socio-economic changes recorded, (87) Sr/(86) Sr values indicate a persisting scenario of low systematic mobility between the different geological regions. Our results suggest that strontium isotope values provide the most germane means to track patterns of human occupation of distinct regions in complex geological landscapes, offering a much higher spatial resolution than oxygen isotopes in the southern Andes. © 2017 Wiley Periodicals, Inc.

  14. Seismic structure and tectonics of the southern Arauco Basin, south-central Chile (~ 38°S)

    NASA Astrophysics Data System (ADS)

    Becerra, Juan; Contreras-Reyes, Eduardo; Arriagada, César

    2013-04-01

    The Arauco Basin is located on the continental shelf near the Chilean subduction zone (~ 38°S). Main deformational stages that affected this setting show a good correlation with Andean constructional phases. We studied the kinematic evolution of the Arauco Basin using high-resolution seismic reflection data across the southern Arauco forearc basin. Three structural domains are identified: (1) Inversion, (2) Extension and (3) Accretion. In addition, seven syn-kinematic sequences have been recognized overlying the Late Carboniferous to Triassic basement, and their relationships with four traditional tectonostratigraphic sequences of the Arauco Basin: (S1) Late Cretaceous syn-extension, (S2) Eocene syn-extension, (S3) and (S4) Eocene syn-inversion, (S5-S6) Miocene syn-inversion with middle extensional structures, and (S7) Pliocene-Quaternary post-inversion and syn-compression. Shortening began in the southern Arauco Basin coeval with a major readjustment of the plate convergence rate (~ 34 Ma) that is represented by inversion structures and kinematic syn-inversion sequences. A marked erosional unconformity (34-23 Ma) represents a subsequent event of erosion/uplift during the Oligocene. A contractional Miocene deformation phase reinforced the inversion tectonic and generated Miocene extensional structures. Since the Pliocene the rapid exhumation of the Nahuelbuta Range allows the emergence of the Arauco Basin. Within the basin, Pliocene and Quaternary sequences were affected by contractional structures including the inversion of the Miocene extensional faults. The contraction along the Arauco Basin can be related to the shift to accretionary conditions of the margin and the oblique collision of the Mocha Fracture Zone (~ 3.6 Ma) at ~ 38°S. The mechanics of regional subsidence which affected the basin during the Miocene cannot be attributed to major scale extensional structures (> 1.0 km).

  15. Water quality comparison of secondary effluent and reclaimed water to ambient river water of southern Okinawa Island via biological evaluation.

    PubMed

    Mano, Hiroyuki; Takeda, Fumihiko; Kitamura, Tomokazu; Okamoto, Seiichiro; Suzuki, Yutaka; Park, Chang-Beom; Yasui, Nobuhito; Kobayashi, Kentarou; Tanaka, Yuji; Yamashita, Naoyuki; Minamiyama, Mizuhiko

    2017-08-08

    The objective of this work was to evaluate the biological effect of the secondary effluent (SE) of a wastewater treatment plant and reclaimed water treated via ultrafiltration (UF) followed by either reverse osmosis (RO) membrane filtration or nanofiltration (NF) to be used for environmental use by comparing the results of algal growth inhibition tests of concentrated samples of the SE and permeates of RO and NF with those of six rivers in southern Okinawa Island. Although the SE water had no adverse effects on the growth of the algae Pseudokirchneriella subcapitata, it could lead to water quality degradation of rivers in terms of its toxic unit value, whereas the use of RO and NF permeates would not lead to such degradation. The recharge of rivers, into which domestic wastewater and livestock effluents might be discharged in southern Okinawa Island, with reclaimed water subjected to advanced treatment could dilute the concentrations of chemicals that cause biological effects and improve the water quality of the rivers, based on the results of the bioassay using P. subcapitata. Comparing the results of bioassays of reclaimed water with those of the ambient water at a site might be effective in assessing the water quality of reclaimed water for environmental use at the site.

  16. A survey of Enterobius vermicularis infection among children on western and southern coastal islands of the Republic of Korea

    PubMed Central

    Park, Jae-Hwan; Han, Eun-Taek; Kim, Won-Hee; Shin, Eun-Hee; Guk, Sang-Mee; Kim, Jae-Lip

    2005-01-01

    To determine the status of Enterobius vermicularis infection among children living on western and southern coastal islands of the Republic of Korea, children (3-10 years) in 39 kindergartens and primary schools were examined using the cello-tape anal swab method, during July and August 2000. Of 1,661 children examined, 307 (18.5%) were found to be positive for E. vermicularis eggs. The highest infection rate (59.3%) was found in a kindergarten and a branch school of Shinyang primary school on Chujado, Jeju-do (Province). Remarkable differences in egg positive rates were observed in different localities. The egg positive rate for boys (21.3%) was significantly higher than that of girls (15.4%) (P = 0.02). However, positive rates were not significantly dependent on age. The results of the present study show that E. vermicularis infection is highly prevalent among pre-school and primary school children living on the western and southern coastal islands of the Republic of Korea, and indicate the need for efforts to control this infection. PMID:16340301

  17. Atmospheric deposition fluxes and solubility over the Southern Indian Ocean: time series on Kerguelen and Crozet Islands.

    NASA Astrophysics Data System (ADS)

    Heimburger, Alexie; Losno, Remi; Triquet, Sylvain; Bon Nguyen, Elisabeth

    2013-04-01

    Atmospheric supplies bringing trace metals are suspected to have a significant impact on biogeochemical processes in High-Nutrient-Low-Chlorophyll waters of the open ocean, such as the Southern Ocean. We recorded time series of atmospheric deposition samples continuously collected over two years on Kerguelen and Crozet Islands in the Southern Indian Ocean. Dust deposition flux and scavenging ratio on Kerguelen Islands were reported in a previous publication [Heimburger et al., GBC, 2012]. Here, we present results of total atmospheric deposition fluxes for a large suite of elements (Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nd, Ni, Pb including isotopes, Rb, S, Si, Sr, Ti, U, V, Zn), which are identified as coming either from sea-salt, crustal or anthropogenic sources. Enrichment factor variabilities for Pb, As, Cr, Cu and V and Pb isotopic ratios highlight the anthropogenic contribution during the austral winter only. For Al, Fe, Mn and Si, deposition fluxes are similar for both Kerguelen and Crozet Islands, which are situated 1300 km apart, and so can be extrapolated for the entire Southern Indian Ocean. Over the entire sampling period, those fluxes are on average equal to 53 ± 2 µg/m²/d, 33 ± 1 µg/m²/d, 0.83 ± 0.04 µg/m²/d and 88 ± 14 µg/m²/d respectively. For the other non-sea-salt elements, we observed differences between flux values from a factor of two to a factor of five with a decreasing gradient from Crozet to Kerguelen Islands. One-month field experiments were also performed during four different austral summers in order to collect rain water on an event basis. Soluble and insoluble fractions were directly separated by filtration and analysed using High Resolution - Inductively Coupled Plasma - Mass Spectrometry and Inductively Coupled Plasma-Atomic Emission Spectrometry as done for deposition samples. Concentrations in rain water samples are very low and difficult to measure accurately mainly because of possible contamination

  18. Distribution, density, and biomass of introduced small mammals in the southern mariana islands

    USGS Publications Warehouse

    Wiewel, A.S.; Adams, A.A.Y.; Rodda, G.H.

    2009-01-01

    Although it is generally accepted that introduced small mammals have detrimental effects on island ecology, our understanding of these effects is frequently limited by incomplete knowledge of small mammal distribution, density, and biomass. Such information is especially critical in the Mariana Islands, where small mammal density is inversely related to effectiveness of Brown Tree Snake (Boiga irregularis) control tools, such as mouse-attractant traps. We used mark-recapture sampling to determine introduced small mammal distribution, density, and biomass in the major habitats of Guam, Rota, Saipan, and Tinian, including grassland, Leucaena forest, and native limestone forest. Of the five species captured, Rattus diardii (sensu Robins et al. 2007) was most common across habitats and islands. In contrast, Mus musculus was rarely captured at forested sites, Suncus murinus was not captured on Rota, and R. exulans and R. norvegicus captures were uncommon. Modeling indicated that neophobia, island, sex, reproductive status, and rain amount influenced R. diardii capture probability, whereas time, island, and capture heterogeneity influenced S. murinus and M. musculus capture probability. Density and biomass were much greater on Rota, Saipan, and Tinian than on Guam, most likely a result of Brown Tree Snake predation pressure on the latter island. Rattus diardii and M. musculus density and biomass were greatest in grassland, whereas S. murinus density and biomass were greatest in Leucaena forest. The high densities documented during this research suggest that introduced small mammals (especially R. diardii) are impacting abundance and diversity of the native fauna and flora of the Mariana Islands. Further, Brown Tree Snake control and management tools that rely on mouse attractants will be less effective on Rota, Saipan, and Tinian than on Guam. If the Brown Tree Snake becomes established on these islands, high-density introduced small mammal populations will likely

  19. Post-glacial mantle evolution in Southern Chile and the development of the Carrán-Los Venados volcanic field (40'20oS)

    NASA Astrophysics Data System (ADS)

    Reagan, M. K.; McGee, L. E.; Nowell, G. M.; Turner, M. B.; Lara, L.; Handley, H. K.

    2016-12-01

    Deglaciation can locally enhance magmatism due to mantle decompression caused by glacial unloading. We investigate the geochemical effects of this process and on what timescale it occurred at the Carrán-Los Venados (CLV) volcanic field (40'20oS) in the Southern Volcanic Zone, Chile. The CLV has been volcanically active from approximately 5ka to its last eruption in 1979AD. It consists of approximately 70 basaltic scoria cones and maars, constructed over extensive inter- to postglacial basal basaltic lava flows. Mafic rocks erupted in this setting therefore provide an ongoing record of mantle evolution in pre-, inter- and post-glacial times. The longer lived, more evolved Puyehue-Cordon Caulle complex is located 20km to the south and has been active from 500ka until the present day. Whole rock major and trace element compositions combined with U-Th and Sr-Nd-Pb isotopic ratios and olivine compositions show a profound difference between the basal lavas underlying the volcanic field and the later monogenetic basalts. Differences in fluid mobile/immobile element ratios and incompatible trace element contents, in addition to changes in olivine Fo contents suggest that the former were produced by melting of a drier, more enriched source, whilst the monogenetic field was sourced by a significantly wetter, more depleted source. The most recent eruption within the field (Mirador) displays characteristics of both sources. We hypothesize that deglaciation drove the decompression and subsequent melting of relatively dry and enriched mantle at higher upwelling rates allowing the eruption of the extensive basal lava flows. As deglaciation slowed and upwelling rates decreased, this source became less dominant and smaller, more isolated fluid-fluxed melting events dominated magma genesis. This change occurred over a narrow window of time - a few thousands of years - suggesting that in such conditions shifts in source, melting dynamics and eruption style can occur relatively

  20. Siliceous productivity changes in Gulf of Ancud sediments (42°S, 72°W), southern Chile, over the last ˜150 years

    NASA Astrophysics Data System (ADS)

    Rebolledo, Lorena; González, Humberto E.; Muñoz, Práxedes; Iriarte, José L.; Lange, Carina B.; Pantoja, Silvio; Salamanca, Marco

    2011-03-01

    We evaluated changes in siliceous export production and the source of organic matter preserved in sediment core MD07-3109H recovered from the Gulf of Ancud, Chiloé Inner Sea (42°S, 72°W, water column depth: 328 m), southern Chile. We analyzed the abundance of siliceous microfossils (diatoms, silicoflagellates, sponge spicules, Chrysophyte cysts, phytoliths), geochemical proxies (weight percent silicon %Si OPAL, organic carbon, total nitrogen, C/N molar), and sediment stable isotopes (δ 13C org, δ 15N). Chronology based on 210Pb and 14C provided an accumulated age of 144 years at the base of the core. Sediments of core MD07-3109H are predominantly marine in origin, averaging δ 13C org=-20.75‰±0.82, δ 15N=8.7±0.35‰, and C/N=8.76±0.36. Marine diatoms compose 94% of the total assemblage of siliceous microfossils. Our record of productivity based on the mass accumulation rates of organic carbon, total nitrogen, Si OPAL, and total diatoms showed high values between 1863 and 1869 AD followed by a declining trend until 1921 AD, a transition period from 1921 to 1959 AD with fluctuating values, and a clear decreasing pattern from 1960 AD to the present. This marked reduction in productivity was associated with decreased precipitation and Puelo River streamflow (41°S), as well as a warmer and more stratified water column, especially since the 1980s.

  1. Biases in determining the diet of jumbo squid Dosidicus gigas (D' Orbigny 1835) (Cephalopoda: Ommastrephidae) off southern-central Chile (34°S-40°S)

    NASA Astrophysics Data System (ADS)

    Ibáñez, Christian M.; Arancibia, Hugo; Cubillos, Luis A.

    2008-12-01

    The diet of jumbo squid ( Dosidicus gigas) off southern-central Chile is described to examine potential biases in the determination of their main prey. Specimens were collected from catches using different fishing gear (jigging, trawl and purse-seine), from July 2003 to January 2004, and from December 2005 to October 2006. The stomach contents were analyzed in terms of frequency of occurrence, number, and weight of prey items and the diet composition was analyzed using Detrended Correspondence Analysis. In the industrial purse-seine fleet for jack mackerel ( Trachurus murphyi), the dominant prey of D. gigas was T. murphyi. In the industrial mid-trawl fishery for Patagonian grenadier ( Macruronus magellanicus), the dominant species in the diet of D. gigas was M. magellanicus. Similarly, Chilean hake ( Merluccius gayi) was the main prey in the diet of D. gigas obtained in the industrial trawl fishery for Chilean hake; and, in both artisanal fisheries (purse-seine for small pelagics and jigging), small pelagic fish and D. gigas were the main prey in the stomach contents of D. gigas. Cannibalism in D. gigas varied between different fleets and probably is related to stress behavior during fishing. The Detrended Correspondence Analysis ordination showed that the main prey in the diet of D. gigas is associated with the target species of the respective fishery. Consequently, biases are associated with fishing gear, leading to an overestimate in the occurrence of the target species in the diet. We recommend analyzing samples from jigging taken at the same time and place where the trawl and purse-seine fleets are operating to avoid this problem, and the application of new tools like stable isotope, heavy metal, and fatty acid signature analyses.

  2. Sequencing at sea: challenges and experiences in Ion Torrent PGM sequencing during the 2013 Southern Line Islands Research Expedition.

    PubMed

    Lim, Yan Wei; Cuevas, Daniel A; Silva, Genivaldo Gueiros Z; Aguinaldo, Kristen; Dinsdale, Elizabeth A; Haas, Andreas F; Hatay, Mark; Sanchez, Savannah E; Wegley-Kelly, Linda; Dutilh, Bas E; Harkins, Timothy T; Lee, Clarence C; Tom, Warren; Sandin, Stuart A; Smith, Jennifer E; Zgliczynski, Brian; Vermeij, Mark J A; Rohwer, Forest; Edwards, Robert A

    2014-01-01

    Genomics and metagenomics have revolutionized our understanding of marine microbial ecology and the importance of microbes in global geochemical cycles. However, the process of DNA sequencing has always been an abstract extension of the research expedition, completed once the samples were returned to the laboratory. During the 2013 Southern Line Islands Research Expedition, we started the first effort to bring next generation sequencing to some of the most remote locations on our planet. We successfully sequenced twenty six marine microbial genomes, and two marine microbial metagenomes using the Ion Torrent PGM platform on the Merchant Yacht Hanse Explorer. Onboard sequence assembly, annotation, and analysis enabled us to investigate the role of the microbes in the coral reef ecology of these islands and atolls. This analysis identified phosphonate as an important phosphorous source for microbes growing in the Line Islands and reinforced the importance of L-serine in marine microbial ecosystems. Sequencing in the field allowed us to propose hypotheses and conduct experiments and further sampling based on the sequences generated. By eliminating the delay between sampling and sequencing, we enhanced the productivity of the research expedition. By overcoming the hurdles associated with sequencing on a boat in the middle of the Pacific Ocean we proved the flexibility of the sequencing, annotation, and analysis pipelines.

  3. Sequencing at sea: challenges and experiences in Ion Torrent PGM sequencing during the 2013 Southern Line Islands Research Expedition

    PubMed Central

    Lim, Yan Wei; Cuevas, Daniel A.; Silva, Genivaldo Gueiros Z.; Aguinaldo, Kristen; Dinsdale, Elizabeth A.; Haas, Andreas F.; Hatay, Mark; Sanchez, Savannah E.; Wegley-Kelly, Linda; Dutilh, Bas E.; Harkins, Timothy T.; Lee, Clarence C.; Tom, Warren; Sandin, Stuart A.; Smith, Jennifer E.; Zgliczynski, Brian; Vermeij, Mark J.A.; Rohwer, Forest

    2014-01-01

    Genomics and metagenomics have revolutionized our understanding of marine microbial ecology and the importance of microbes in global geochemical cycles. However, the process of DNA sequencing has always been an abstract extension of the research expedition, completed once the samples were returned to the laboratory. During the 2013 Southern Line Islands Research Expedition, we started the first effort to bring next generation sequencing to some of the most remote locations on our planet. We successfully sequenced twenty six marine microbial genomes, and two marine microbial metagenomes using the Ion Torrent PGM platform on the Merchant Yacht Hanse Explorer. Onboard sequence assembly, annotation, and analysis enabled us to investigate the role of the microbes in the coral reef ecology of these islands and atolls. This analysis identified phosphonate as an important phosphorous source for microbes growing in the Line Islands and reinforced the importance of L-serine in marine microbial ecosystems. Sequencing in the field allowed us to propose hypotheses and conduct experiments and further sampling based on the sequences generated. By eliminating the delay between sampling and sequencing, we enhanced the productivity of the research expedition. By overcoming the hurdles associated with sequencing on a boat in the middle of the Pacific Ocean we proved the flexibility of the sequencing, annotation, and analysis pipelines. PMID:25177534

  4. Assessing the Effectiveness of Breast Cancer Education Workshops among Samoan and Pacific Islander Women in Southern California

    PubMed Central

    Schmidt-Vaivao, Dorothy Etimani; Lutu, Genesis; Tulua-Tata, Alisi; Hannemann, Marion; Tisnado, Diana M.

    2015-01-01

    Background Samoans experience among the worst five-year breast cancer survival rates in the U.S., largely due to late stage diagnosis. There is great potential for screening interventions to reduce cancer mortality among Samoans. This paper examines the effectiveness of a culturally and linguistically tailored breast cancer education workshop for Samoan and other Pacific Islander women in Southern California. Methods Educational workshops were conducted in churches, homes, and the Samoan National Nurses Association office to Pacific Islander women. Effectiveness was assessed using pre- and post-tests. Self-administered questionnaires queried participants about demographics, access, personal or family breast cancer history, screening knowledge and behaviors, and plans to obtain screening (n=495). Results Participants were predominantly Samoan, with 57% reporting they were ≥40 years of age. At pre-test, half of the participants did not know how to perform Breast Self Examination (BSE), 40% never had a Clinical Breast Examination (CBE), and 30% never had a mammogram. Less than 40% reported having a mammogram in the past two years. At post-test, 98% reported increased knowledge. Older women were more likely to report plans for screening at post-test. Conclusions Health educators in Samoan and other Pacific Islander communities must recognize and appropriately address screening barriers such as cultural beliefs and lack of knowledge, and should consider working with important institutions such as the church. PMID:25750596

  5. Surface ozone in the Southern Hemisphere: 20 years of data from a site with a unique setting in El Tololo, Chile

    NASA Astrophysics Data System (ADS)

    Anet, Julien G.; Steinbacher, Martin; Gallardo, Laura; Velásquez Álvarez, Patricio A.; Emmenegger, Lukas; Buchmann, Brigitte

    2017-05-01

    The knowledge of surface ozone mole fractions and their global distribution is of utmost importance due to the impact of ozone on human health and ecosystems and the central role of ozone in controlling the oxidation capacity of the troposphere. The availability of long-term ozone records is far better in the Northern than in the Southern Hemisphere, and recent analyses of the seven accessible records in the Southern Hemisphere have shown inconclusive trends. Since late 1995, surface ozone is measured in situ at "El Tololo", a high-altitude (2200 m a.s.l.) and pristine station in Chile (30° S, 71° W). The dataset has been recently fully quality controlled and reprocessed. This study presents the observed ozone trends and annual cycles and identifies key processes driving these patterns. From 1995 to 2010, an overall positive trend of ˜ 0.7 ppb decade-1 is found. Strongest trends per season are observed in March and April. Highest mole fractions are observed in late spring (October) and show a strong correlation with ozone transported from the stratosphere down into the troposphere, as simulated with a model. Over the 20 years of observations, the springtime ozone maximum has shifted to earlier times in the year, which, again, is strongly correlated with a temporal shift in the occurrence of the maximum of simulated stratospheric ozone transport at the site. We conclude that background ozone at El Tololo is mainly driven by stratospheric intrusions rather than photochemical production from anthropogenic and biogenic precursors. The major footprint of the sampled air masses is located over the Pacific Ocean. Therefore, due to the negligible influence of local processes, the ozone record also allows studying the influence of El Niño and La Niña episodes on background ozone levels in South America. In agreement with previous studies, we find that, during La Niña conditions, ozone mole fractions reach higher levels than during El Niño conditions.

  6. Early formation of gnammas (weathering pits) in a recently glaciated area of Torres del Paine, southern Patagonia (Chile)

    NASA Astrophysics Data System (ADS)

    Domínguez-Villar, David

    2006-06-01

    Incipient gnammas (weathering pits) were identified and measured in the Francés Valley of Torres del Paine, southern Patagonia. The gnammas were located on the granite blocks of a lateral moraine deposited during a Late Holocene neoglacial advance. The gnammas were measured for maximum and minimum depth, length, and width in addition to other observations. Based on these measurements, the surface area and the volume of the gnammas were calculated. Most of the gnammas have < 1 L of rock volume eroded, and the maximum depth is always < 10 cm. The gnammas do not develop erosional spillways. A high correlation exists between maximum and minimum depths, indicating these values are not completely independent. Thus, the depth ratio has been used to characterize the gnammas for discrete locations. The gnammas from Francés Valley belong to a unique normal population and a δ-value based on the depth ratio was defined to represent this population. The δ of Francés Valley is 1.33 ± 0.07, comparable with the lowest values of other stations around the globe. I suggest that the δ-value could be used as an indicator of gnamma evolution.

  7. Islands in the Sky: Ecophysiological Cloud-Vegetation Linkages in Southern Appalachian Mountain Cloud Forests

    NASA Astrophysics Data System (ADS)

    Reinhardt, K.; Emanuel, R. E.; Johnson, D. M.

    2013-12-01

    Mountain cloud forest (MCF) ecosystems are characterized by a high frequency of cloud fog, with vegetation enshrouded in fog. The altitudinal boundaries of cloud-fog zones co-occur with conspicuous, sharp vegetation ecotones between MCF- and non-MCF-vegetation. This suggests linkages between cloud-fog and vegetation physiology and ecosystem functioning. However, very few studies have provided a mechanistic explanation for the sharp changes in vegetation communities, or how (if) cloud-fog and vegetation are linked. We investigated ecophysiological linkages between clouds and trees in Southern Appalachian spruce-fir MCF. These refugial forests occur in only six mountain-top, sky-island populations, and are immersed in clouds on up to 80% of all growing season days. Our fundamental research questions was: How are cloud-fog and cloud-forest trees linked? We measured microclimate and physiology of canopy tree species across a range of sky conditions (cloud immersed, partly cloudy, sunny). Measurements included: 1) sunlight intensity and spectral quality; 2) carbon gain and photosynthetic capacity at leaf (gas exchange) and ecosystem (eddy covariance) scales; and 3) relative limitations to carbon gain (biochemical, stomatal, hydraulic). RESULTS: 1) Midday sunlight intensity ranged from very dark (<30 μmol m-2 s-1, under cloud-immersed conditions) to very bright (>2500 μmol m-2 s-1), and was highly variable on minute-to-minute timescales whenever clouds were present in the sky. Clouds and cloud-fog increased the proportion of blue-light wavelengths 5-15% compared to sunny conditions, and altered blue:red and red:far red ratios, both of which have been shown to strongly affect stomatal functioning. 2) Cloud-fog resulted in ~50% decreased carbon gain at leaf and ecosystem scales, due to sunlight levels below photosynthetic light-saturation-points. However, greenhouse studies and light-response-curve analyses demonstrated that MCF tree species have low light

  8. Mechanisms causing size differences of the land hermit crab Coenobita rugosus among eco-islands in Southern Taiwan.

    PubMed

    Hsu, Chia-Hsuan; Soong, Keryea

    2017-01-01

    Numerous environmental factors can influence body size. Comparing populations in different ecological contexts is one potential approach to elucidating the most critical of such factors. In the current study, we found that the body size of the land hermit crab Coenobita rugosus was significantly larger on Dongsha Island in the South China Sea than on other eco-islands around Southern Taiwan. We hypothesized that this could be due to differences in (1) shell resources, (2) parasite impact, (3) competition, (4) predation, and (5) food. We found no supporting evidence for the first three hypotheses; the shells used by the hermit crabs on Dongsha were in poorer condition than were those used elsewhere, extremely few individuals in the region had ectoparasites, and the density of hermit crabs varied considerably among localities within each island. However, significantly higher percentages of C. rugosus reached age 3 years on Dongsha than at Siziwan bay in Taiwan. Two growth rate indices inferred from size structures suggested faster growth on Dongsha than at Siziwan. The condition index (i.e., the body mass/shield length ratio of C. rugosus) was also greater on Dongsha than at Siziwan. Therefore, Dongsha hermit crabs seem to have superior diet and growth performance. Seagrass debris accumulation at the shore of Dongsha was considerable, whereas none was observed at Siziwan or on the other islands, where dicot leaves were the dominant food item for the vegetarian hermit crabs. We then experimentally evaluated the possible role of seagrass as food for C. rugosus. The crabs on Dongsha preferred seagrass to dicot leaves, and their growth increment was faster when they fed on seagrass than when they fed on dicot leaves; no such differences were found in the Siziwan hermit crabs. The aforementioned results are compatible with the food hypothesis explaining the size differences among the islands. The predator hypothesis could explain the greater life span but not the other

  9. Mechanisms causing size differences of the land hermit crab Coenobita rugosus among eco-islands in Southern Taiwan

    PubMed Central

    Hsu, Chia-Hsuan

    2017-01-01

    Numerous environmental factors can influence body size. Comparing populations in different ecological contexts is one potential approach to elucidating the most critical of such factors. In the current study, we found that the body size of the land hermit crab Coenobita rugosus was significantly larger on Dongsha Island in the South China Sea than on other eco-islands around Southern Taiwan. We hypothesized that this could be due to differences in (1) shell resources, (2) parasite impact, (3) competition, (4) predation, and (5) food. We found no supporting evidence for the first three hypotheses; the shells used by the hermit crabs on Dongsha were in poorer condition than were those used elsewhere, extremely few individuals in the region had ectoparasites, and the density of hermit crabs varied considerably among localities within each island. However, significantly higher percentages of C. rugosus reached age 3 years on Dongsha than at Siziwan bay in Taiwan. Two growth rate indices inferred from size structures suggested faster growth on Dongsha than at Siziwan. The condition index (i.e., the body mass/shield length ratio of C. rugosus) was also greater on Dongsha than at Siziwan. Therefore, Dongsha hermit crabs seem to have superior diet and growth performance. Seagrass debris accumulation at the shore of Dongsha was considerable, whereas none was observed at Siziwan or on the other islands, where dicot leaves were the dominant food item for the vegetarian hermit crabs. We then experimentally evaluated the possible role of seagrass as food for C. rugosus. The crabs on Dongsha preferred seagrass to dicot leaves, and their growth increment was faster when they fed on seagrass than when they fed on dicot leaves; no such differences were found in the Siziwan hermit crabs. The aforementioned results are compatible with the food hypothesis explaining the size differences among the islands. The predator hypothesis could explain the greater life span but not the other

  10. Rapid uplift during 2007-2012 at Laguna del Maule volcanic field, Andean Southern Volcanic Zone, Chile

    NASA Astrophysics Data System (ADS)

    Le Mevel, H.; Feigl, K.; Ali, T.; Cordova V., M. L.; DeMets, C.; Singer, B. S.

    2012-12-01

    The Laguna del Maule (LdM) volcanic field includes an unusual concentration of post-glacial rhyolitic lava coulees and domes, dated between 24 to 2 thousand years old that cover more than 100 square kilometers and erupted from 24 vents that encircle a 20-km-diameter lake basin on the range crest. The recent concentration of rhyolite is unparalleled in the Southern Volcanic Zone of the Andes. Moreover, the western portion of the LdM volcanic field has experienced rapid uplift since 2007, leading to questions about the current configuration of the magmatic system and processes that drive the ongoing inflation. We aim to quantify the active deformation of the LdM volcanic field and its evolution with time. To do so, we use interferometric synthetic aperture radar (InSAR) data acquired by three satellite missions: Envisat in 2003 and 2004, ALOS between 2007 and 2010, and TerraSAR-X in 2012. An interferogram spanning March 2003 to February 2004 "shows no deformation" (Fournier et al., 2010). From 2007 through 2012, however, the shortening of the satellite-to-ground distance revealed a range change rate of greater than 200 mm/yr along the radar line of sight. The deformation includes a circular area 20 km in diameter centered on the western portion of the circle of young rhyolite domes. To analyze the InSAR results, we employ the General Inversion for Phase Technique (GIPhT; Feigl and Thurber, 2009; Ali and Feigl, 2012). We have considered several hypotheses to interpret this deformation. Artefacts such as orbital errors, atmospheric perturbations or topographic contribution cannot account for the observed signal. We also reject the hypothesis of uplift due to gravitational unloading of the crust based on our modeling of independently measured lake level variations over the observed time interval. We thus attribute the deformation to the intrusion of magma into the upper crust below the southwest region of the LdM volcanic field. The best fit to the InSAR data is

  11. Influence of different forest management practices and vegetation cover on runoff generation and sediment flux in the Coastal Range of Southern Chile

    NASA Astrophysics Data System (ADS)

    Mohr, Christian; Bronstert, Axel; Huber, Anton; Iroumé, Andrés.

    2010-05-01

    Favorable climatic and hydrological conditions make Chile to one of the leading timber and cellulose exporting nations with one of the biggest growing rates worldwide. The intensification of this sector comes along with large-scale land use changes affecting the soil's water conservation function of the geoecosystem. This research focuses on the influence of different forest management practices and vegetation cover on the runoff-generation and the sediment transport in Pinus radiata D.Don planted micro-catchments in the coastal range of southern Chile. One catchment is kept as control without silvicultural intervention during the whole study (catchment Nr. 1) and another was thinned selectively in the rainy season 2009 (catchment Nr. 2). Two catchments are harvested by clear-cuts, whereby one clear-cut already took place in June-Aug. 2009 during the rainy season (catchment Nr. 3) and the other is planned for the dry season in February 2010 (catchment Nr. 4). One catchment - formerly planted with Pinus radiata - was already clear cut in 2007 (catchment Nr. 5). For long-term research, the catchments are equipped with V-notched weirs, sediment sampling devices, rainfall redistribution test-plots and TDR-clusters. Single events of stronger precipitation and runoff are sampled and a self-designed rainfall-simulator is used to gain additional information of the infiltration, overland flow and sediment transport processes. Annual interception loss is approx. 20 % of the yearly avaraged precipitation of 1300mm. During the calibration period, all catchments show high similarities in discharge and a dominance of subsurface flow. In all catchments, diel cycles of different amplitude within the streamflow were registered. By the beginning of the rainy season in May, the soils in all catchments were saturated completely up to depth of 250cm. Only catchment 5 showed higher and irregular contents of soil water due to missing vegetation cover and recent morphodynamics. To the end

  12. Rapid uplift in Laguna del Maule volcanic field of the Andean Southern Volcanic Zone (Chile) measured by satellite radar interferometry

    NASA Astrophysics Data System (ADS)

    Feigl, K.; Ali, T.; Singer, B. S.; Pesicek, J. D.; Thurber, C. H.; Jicha, B. R.; Lara, L. E.; Hildreth, E. W.; Fierstein, J.; Williams-Jones, G.; Unsworth, M. J.; Keranen, K. M.

    2011-12-01

    The Laguna del Maule (LdM) volcanic field of the Andean Southern Volcanic Zone extends over 500 square kilometers and comprises more than 130 individual vents. As described by Hildreth et al. (2010), the history has been defined from sixty-eight Ar/Ar and K-Ar dates. Silicic eruptions have occurred throughout the past 3.7 Ma, including welded ignimbrite associated with caldera formation at 950 ka, small rhyolitic eruptions between 336 and 38 ka, and a culminating ring of 36 post-glacial rhyodacite and rhyolite coulees and domes that encircle the lake. Dating of five post-glacial flows implies that these silicic eruptions occurred within the last 25 kyr. Field relations indicate that initial eruptions comprised modest volumes of mafic rhyodacite magma that were followed by larger volumes of high silica rhyolite. The post-glacial flare-up of silicic magmatism from vents distributed around the lake, is unprecedented in the history of this volcanic field. Using satellite radar interferometry (InSAR), Fournier et al. (2010) measured uplift at a rate of more than 180 mm/year between 2007 and 2008 in a round pattern centered on the west side of LdM. More recent InSAR observations suggest that rapid uplift has continued from 2008 through early 2011. In contrast, Fournier et al. found no measurable deformation in an interferogram spanning 2003 through 2004. In this study, we model the deformation field using the General Inversion of Phase Technique (GIPhT), as described by Feigl and Thurber (2009). Two different models fit the data. The first model assumes a sill at ~5 km depth has been inflating at a rate of more than 20 million cubic meters per year since 2007. The second model assumes that the water level in the lake dropped at a rate of 20 m/yr from January 2007 through February 2010, thus reducing the load on an elastic simulation of the crust. The rate of intrusion inferred from InSAR is an order of magnitude higher than the average rate derived from well-dated arc

  13. Phylogeographic history and gene flow among giant Galápagos tortoises on southern Isabela Island.

    PubMed

    Ciofi, Claudio; Wilson, Gregory A; Beheregaray, Luciano B; Marquez, Cruz; Gibbs, James P; Tapia, Washington; Snell, Howard L; Caccone, Adalgisa; Powell, Jeffrey R

    2006-03-01

    Volcanic islands represent excellent models with which to study the effect of vicariance on colonization and dispersal, particularly when the evolution of genetic diversity mirrors the sequence of geological events that led to island formation. Phylogeographic inference, however, can be particularly challenging for recent dispersal events within islands, where the antagonistic effects of land bridge formation and vicariance can affect movements of organisms with limited dispersal ability. We investigated levels of genetic divergence and recovered signatures of dispersal events for 631 Galápagos giant tortoises across the volcanoes of Sierra Negra and Cerro Azul on the island of Isabela. These volcanoes are among the most recent formations in the Galápagos (<0.7 million years), and previous studies based on genetic and morphological data could not recover a consistent pattern of lineage sorting. We integrated nested clade analysis of mitochondrial DNA control region sequences, to infer historical patterns of colonization, and a novel Bayesian multilocus genotyping method for recovering evidence of recent migration across volcanoes using eleven microsatellite loci. These genetic studies illuminate taxonomic distinctions as well as provide guidance to possible repatriation programs aimed at countering the rapid population declines of these spectacular animals.

  14. Pap smear screening rates: coverage on the southern queen charlotte islands.

    PubMed

    Calam, B; Bass, M; Deagle, G

    1992-05-01

    A cross-sectional study of 196 women on the Queen Charlotte Islands showed that significantly fewer Haida women than non-Native women had adequate cervical screening. Differences were most marked in the 60 and older age group. Qualitative research to elucidate cultural factors could aid in planning screening programs that would be accepted by all women at risk in the community.

  15. Phylogeographic History and Gene Flow Among Giant Galápagos Tortoises on Southern Isabela Island

    PubMed Central

    Ciofi, Claudio; Wilson, Gregory A.; Beheregaray, Luciano B.; Marquez, Cruz; Gibbs, James P.; Tapia, Washington; Snell, Howard L.; Caccone, Adalgisa; Powell, Jeffrey R.

    2006-01-01

    Volcanic islands represent excellent models with which to study the effect of vicariance on colonization and dispersal, particularly when the evolution of genetic diversity mirrors the sequence of geological events that led to island formation. Phylogeographic inference, however, can be particularly challenging for recent dispersal events within islands, where the antagonistic effects of land bridge formation and vicariance can affect movements of organisms with limited dispersal ability. We investigated levels of genetic divergence and recovered signatures of dispersal events for 631 Galápagos giant tortoises across the volcanoes of Sierra Negra and Cerro Azul on the island of Isabela. These volcanoes are among the most recent formations in the Galápagos (<0.7 million years), and previous studies based on genetic and morphological data could not recover a consistent pattern of lineage sorting. We integrated nested clade analysis of mitochondrial DNA control region sequences, to infer historical patterns of colonization, and a novel Bayesian multilocus genotyping method for recovering evidence of recent migration across volcanoes using eleven microsatellite loci. These genetic studies illuminate taxonomic distinctions as well as provide guidance to possible repatriation programs aimed at countering the rapid population declines of these spectacular animals. PMID:16387883

  16. The volcano-tectonic dynamic of Ischia island (Southern Italy): inference from magnetotelluric survey

    NASA Astrophysics Data System (ADS)

    Carlino, Stefano; Giulia Di Giuseppe, Maria; Troiano, Antonio

    2017-04-01

    A magnetotelluric survey of the central-western sector of the Ischia Island has been performed with the aim to reconstruct two resistivity profiles (N-S and WSW-WNE), about 5km and 3km long respectively, and to infer the main geological features of the crust (0-3km in depth), such as its thermal state, fluid circulations and structural discontinuities. The interpretation of data provides new evidences on both the thermal state of the central-western sector of the island and the circulation of geothermal fluids, and confirms the presence of a crystalline structure (intrusive rocks with very low permeability) located beneath the Mount Epomeo block, which possibly represents the apical part of a degassed and cooling magmatic source. This result is a further evidence of the presence of a very shallow magmatic intrusion beneath the island (<2km), possibly a laccolith, which has been the source of volcanic activity since at least 29ka. The study of the crustal geology of the island, its thermal state and rheology, and the assessment of the magma volume at depth, are fundamental elements to understand the volcanic risk. This latter is possibly strictly correlated to the renewal of Mt Epomeo resurgence process, which in turn is pushed by the shallow laccolith.

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

    PubMed

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

    2015-01-01

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

  18. Cytotoxicity of Crude Lectins from Red Macroalgae from the Southern Coast of Java Island, Gunung Kidul Regency, Yogyakarta, Indonesia

    NASA Astrophysics Data System (ADS)

    Anam, C.; Chasanah, E.; Perdhana, B. P.; Fajarningsih, ND; Yusro, N. F.; Sari, A. M.; Nursiwi, A.; Praseptiangga, D.; Yunus, A.

    2017-04-01

    Lectins or carbohydrate-binding proteins, are widely distributed in nature, including in marine algae. It may have been considered that binding specificity of lectins to some carbohydrates provokes to produce many unique biological activities, including cell agglutination, mitogenic activity, and antitumor activity. The aim of this study was to determine the cytotoxicity of crude lectins from red macroalgae collected from the southern coast of Java Island, Gunung Kidul Regency, Yogyakarta against MCF-7 and HeLa cancer cells. In vitro MTT assay was used in this study. The results showed that less than 50% of MCF-7 and HeLa cancer cells growth were inhibited by the crude lectins from five species of red macro algae used in this study. The highest inhibition ability shown in the red alga A. nana was able to kill 47.68% of HeLa cervical cancer cells.

  19. Strain Partitioning, Current Tectonics and Deformation on the Southern Queen Charlotte Fault, Northern Vancouver Island, and the Adjacent Mainland

    NASA Astrophysics Data System (ADS)

    Hippchen, S.; Mazzotti, S.

    2010-12-01

    The area south of the Queen Charlotte Islands and north of Vancouver Island is characterized by transition from the Cascadia subduction zone to the Queen Charlotte transform fault zone. The tectonic setting involves Pacific, North American, Juan de Fuca, Explorer plate, and Winona block; as well as Queen Charlotte and Revere-Dellwood-Wilson fault, Explorer ridge, Nootka fault, and the Cascadia subduction zone. Using GPS campaign data from 1993 to 2008 we derive a crustal velocity field for North Vancouver Island, southern Queen Charlotte Islands and the adjacent mainland. This velocity data is the basis for interpretation of the tectonics of the transition from the plate convergent to transform boundaries. Our GPS data show significant shear velocities in the Bella Coola region, ~ 250 km inland from the Queen Charlotte fault. At that distance interseismic and postseismic effects are expected to be small, and there is very little seismic activity in the area. We use viscoelastic models to better understand the discrepancy between the GPS data and the seismic data, and to find out what percentage of the deformation in the region is transient deformation, related to the earthquake cycle, and which part is permanent ongoing deformation, distributed off the continental margin. To constrain the model, we use the rheology and structure of the region, with reasonable values for elastic thickness and viscosity. If the results suggest that visco-elastic deformation associated with the Q.C. fault is not the cause for the GPS results, other possible explanations (e.g., rigid rotation) will be considered. Two end-member models to describe how the Pacific/North America plate convergence is accommodated off the Queen Charlotte Islands have been developed by others. They assume either internal crustal shortening or underthrusting of the Pacific plate. With the new GPS data we can determine which model explains the tectonic situation more appropriately. Earlier model results

  20. Historical Earthquakes and Expected Seismic Damage at Ischia Island, Resurgent Caldera (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Carlino, S.; Cubellis, E.

    2005-05-01

    Information on the seismicity of the Ischia island spans about eight centuries, starting from 1228. This is characterized by the occurence of earthquakes with low energy and high intensity. The most recent earthquake of 1883 caused 2333 deaths and the destruction of the historical and environmental heritage of some areas of the island, specially at Casamicciola town. This event (Imax = XI degree MCS), represents an important date in the prevention of natural disasters, in that it was after this earthquake that the first Seismic Safety Act in Italy was passed. After the 1883 earthquake there was a period of seismic quiescence except for some isolated events felt at beginning of the last century and the very occasional micro-earthquakes recorded in the last 20 years in the northern part of the island. The epicenter of all known earthquakes are on the northern slope of Mt. Epomeo (787 m a. s.l.) resurgent block, while analysis of the effects of earthquakes and the geological structures allows us to evaluate the stress fields that generate the earthquakes. The Mt. Epomeo is a resurgent structure in the central sector of the island, whose uplift is correlated to the caldera resurgence process, for the increase of pressure of shallow magma reservoir. The caldera was formed after a large explosive eruption that deposited the Mt. Epomeo Green Tuff, about 55 ka B.P. The uplift, which started about 30 ka B.P., was of about 900 meters. The resurgent structure is bordered by a system of faults and fractures, with NW-SE, NE-SW and N-S strike and along these faults, in the northern sector, the seismicity has been localized. In a volcanic area, interpretation of the mechanisms of release and propagation of seismic energy is made even more complex as the stress field that acts at a regional level is compounded by that generated from migration of magmatic masses towards the surface, as well as the rheologic properties of the rocks dependent on the high geothermic gradient. Such

  1. The Seismogenic Coupling Zone in Southern Central Chile, 38° S: A Reflection seismic image of the subduction zone (Project TIPTEQ)

    NASA Astrophysics Data System (ADS)

    Schulze, A.; Micksch, U.; Krawczyk, C. M.; Ryberg, T.; Stiller, M.

    2006-12-01

    The multi-disciplinary project TIPTEQ (from The Incoming Plate to mega-Thrust EarthQuake processes) investigates the seismogenic coupling zone in Southern Central Chile and the associated subduction zone processes between the Pacific Ocean and the volcanic arc. The reflection seismic component of TIPTEQ includes a 110 km long profile which spans from the coast over the down-dip end of the seismogenic coupling zone, crossing the 1960 Valdivia earthquake hypocentre. 180 three-component geophones were deployed (100 m spacing) along an 18 km wide spread whereof 4.5 km were shifted in a daily roll-along. With 100 borehole shots, 1.5 km apart, this up to 8-fold covered line delivers a high-resolution image of the seismogenic coupling zone. 15 additional shots in an expanding spread profiling configuration focussed on the seismogenic coupling zone. SH wave source signals were generated to yield an improved picture of the petrophysical contrasts within the system. The SPOC-South wide-angle data velocity model is combined with a first-break tomography velocity model to get an advanced migration image. The subducting Nazca plate can be traced from a depth of 25 km below the coast down to a depth of 50 km at the eastern end of the profile. Structural evidence suggests that material is transported down in a subduction channel. From slow uplift of the Coastal Cordillera we conclude that basal accretion of parts of this material controls the seismic architecture and growth of the south Chilean crust. Between depths of 5 to 25 km several bright reflectivity spots can be seen in the upper plate, which may suggest fluid traps in the accretionary wedge. The tomographic p-wave velocity model reaches approximately 10 km depth. Its segmentation corresponds to the geological units mapped at surface. The sediment thickness in the Central Valley is approx. 3 km, and we see prominent fault systems like the Lanalhue fault zone also in the tomographic model. At present, almost no seismicity

  2. Responses of nitrogen and carbon deposition rates in Comau Fjord (42°S, southern Chile) to natural and anthropogenic impacts during the last century

    NASA Astrophysics Data System (ADS)

    Mayr, Christoph; Rebolledo, Lorena; Schulte, Katharina; Schuster, Astrid; Zolitschka, Bernd; Försterra, Günter; Häussermann, Verena

    2014-04-01

    Carbon isotopes and C/N ratios are frequently used to separate allochthonous and autochthonous organic matter input into marine shelf sediments. We test the applicability of this approach for the sediment record from Comau Fjord in southern Chile (42°S) with the aim to reconstruct carbon and nitrogen mass accumulation rates and to determine their allochthonous and autochthonous sources for the last century. Comparisons with isotopic and geochemical signatures of potential organic matter sources demonstrate that mixtures between terrigenous soil and peat on the one hand and marine planktonic organic matter on the other hand readily explain variations of organic carbon (δ13Corg) and nitrogen (δ15N) isotopes as well as in C/N and N/C ratios and explain differences in absolute values of these parameters along a transect of cores. Nitrogen mass accumulation rates, calculated from δ15N and C/N ratio, and carbon mass accumulation rates, calculated from δ13Corg and N/C ratios of terrigenous organic matter, varied considerably less compared to those of autochthonous planktonic organic matter. Autochthonous carbon accumulation rates increased from between 1.2 and 5.2 g m-2 a-1 at the beginning of the last century to values between 21.5 and 29.9 g m-2 a-1 around the turn of the millennium. Even if the highest amount of diagenetic degradation is considered the mass accumulation rates increased by at least a factor of 2 within the last decades of the 20th century. The reasons for such a shift in primary productivity are discussed (1) in terms of recent climatic change in northwestern Patagonia possibly having lowered fluvial inflow into Comau Fjord and (2) in relation to anthropogenic eutrophication by rapidly expanding aquaculture. Given that allochthonous mass-accumulation rates remained fairly constant, we conclude that anthropogenic eutrophication caused by aquaculture is the more likely explanation for increased carbon and nitrogen accumulation rates in the last two

  3. Stable isotope evidence for an atmospheric origin of desert nitrate deposits in northern Chile and southern California, U.S.A.

    USGS Publications Warehouse

    Böhlke, J.K.; Ericksen, G.E.; Revesz, K.

    1997-01-01

    Natural surficial accumulations of nitrate-rich salts in the Atacama Desert, northern Chile, and in the Death Valley region of the Mojave Desert, southern California, are well known, but despite many geologic and geochemical studies, the origins of the nitrates have remained controversial. N and O isotopes in nitrate, and S isotopes in coexisting soluble sulfate, were measured to determine if some proposed N sources could be supported or rejected, and to determine if the isotopic signature of these natural deposits could be used to distinguish them from various types of anthropogenic nitrate contamination that might be found in desert groundwaters. High-grade caliche-type nitrate deposits from both localities have ??15N values that range from -5 to +5???, but are mostly near 0???. Values of ??15N near 0??? are consistent with either bulk atmospheric N deposition or microbial N fixation as major sources of the N in the deposits. ??18O values of those desert nitrates with ??15N near 0??? range from about +31 to + 50??? (V-SMOW), significantly higher than that of atmospheric O2 (+ 23.5???). Such high values of ??18O are considered unlikely to result entirely from nitrification of reduced N, but rather resemble those of modern atmospheric nitrate in precipitation from some other localities. Assuming that limited modern atmospheric isotope data are applicable to the deposits, and allowing for nitrification of co-deposited ammonium, it is estimated that the fraction of the nitrate in the deposits that could be accounted for isotopically by atmospheric N deposition may be at least 20% and possibly as much as 100%. ??34S values are less diagnostic but could also be consistent with atmospheric components in some of the soluble sulfates associated with the deposits. The stable isotope data support the hypothesis that some high-grade caliche-type nitrate-rich salt deposits in some of the Earth's hyperarid deserts represent long-term accumulations of atmospheric deposition

  4. The effects of natural disturbances, reef state, and herbivorous fish densities on ciguatera poisoning in Rarotonga, southern Cook Islands.

    PubMed

    Rongo, Teina; van Woesik, Robert

    2013-03-15

    Ciguatera poisoning is a critical public-health issue among Pacific island nations. Accurately predicting ciguatera outbreaks has become a priority, particularly in Rarotonga in the southern Cook Islands, which has reported the highest incidence of ciguatera poisoning globally. Since 2006, however, cases of ciguatera poisoning have declined, and in 2011 ciguatera cases were the lowest in nearly 20 years. Here we examined the relationships between cases of ciguatera poisoning, from 1994 to 2011, and: (i) coral cover, used as a proxy of reef state, (ii) the densities of herbivorous fishes, and (iii) reef disturbances. We found that coral cover was not a good predictor of cases of ciguatera poisoning, but high densities of the herbivorous fish Ctenochaetus striatus and reef disturbances were both strong predictors of ciguatera poisoning. Yet these two predictors were correlated, because the densities of C. striatus increased only after major cyclones had disturbed the reefs. Since 2006, the number of cyclones has decreased considerably in Rarotonga, because of the climatic shift toward the negative phase of the Pacific Decadal Oscillation. We suggest that fewer cyclones have led to decreases in both the densities of C. striatus and of the number of reported cases of ciguatera poisoning in Rarotonga. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Atmospheric deposition fluxes of 26 elements over the Southern Indian Ocean: Time series on Kerguelen and Crozet Islands

    NASA Astrophysics Data System (ADS)

    Heimburger, Alexie; Losno, RéMi; Triquet, Sylvain; Nguyen, Elisabeth Bon

    2013-04-01

    deposition of dust is suspected to have a significant impact on biogeochemical processes in high-nutrient-low-chlorophyll waters of the open ocean. In this study, we report time series of atmospheric deposition samples collected over two years at three different sites on Kerguelen and Crozet Islands in the Southern Indian Ocean. Total atmospheric deposition fluxes were measured for a large suite of elements (Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nd, Ni, Pb, Rb, S, Si, Sr, Ti, U, V, and Zn). Most of them are identified as coming from sea-salt or crustal sources, but enrichment factor variabilities of Pb, As, Cr, Cu, and V highlight an anthropogenic contribution during the austral winter for these five elements. For Al, Fe, Mn, and Si, deposition fluxes are similar for both Kerguelen and Crozet Islands. Fluxes for the other non-sea-salt elements exhibit differences below a factor of five with a decreasing gradient from Crozet to Kerguelen.

  6. Modulation of the thermo-rheological properties of the crust beneath Ischia Island (Southern Italy) on the ground deformation pattern

    NASA Astrophysics Data System (ADS)

    Castaldo, Raffaele; Gola, Gianluca; Santilano, Alessandro; De Novellis, Vincenzo; Pepe, Susi; Manzo, Mariarosaria; Manzella, Adele; Tizzani, Pietro

    2017-04-01

    We present a model able to simulate the physical process responsible for the long-term ground deformation of Ischia Island Volcano (Southern Italy) by considering the role of the thermo-rheological properties of the crust. To this aim, we develop and implement in a Finite Element (FE) environment an innovative approach that integrates and homogenizes a large amount of data derived from several and different observation techniques (i.e, geological, geophysical and remote sensing). In detail, the main steps of the proposed approach are: (i) the generation of a 3D geological model of the crust beneath the Island by merging the available geological and geophysical information; (ii) the optimization of a 3D thermal model by exploiting the thermal measurements available in literature; (iii) the definition of the 3D B/D (Brittle/Ductile) transition by using the temperature distribution of the crust and the physical information of the rocks; (iv) the optimization of the ground deformation velocity model (that takes into account the rheological stratification) by considering the spatial and temporal information detected via satellite multi-orbit C-Band SAR (Synthetic Aperture Radar) measurements acquired during the 1992-2010 time period. The achieved results allow investigating the physical process responsible for the observed ground deformation pattern. In particular, they reveal how the rheology modulates the spatial and temporal evolution of long-term subsidence phenomenon, highlighting a coupling effect of the viscosities of the rocks and the gravitational loading of the volcano edifice. Moreover, the achieved results provide a very detailed and realistic image of the subsurface crust of the Ischia Island Volcano in order to study the ongoing deformation phenomena.

  7. Deterioration of coastal groundwater quality in Island and mainland regions of Ramanathapuram District, Southern India.

    PubMed

    Sivasankar, Venkataramann; Ramachandramoorthy, Thiagarajan; Chandramohan, A

    2013-01-01

    A study was carried out in the Island and mainland regions of Ramanathapuram District to characterize the physico-chemical characteristics of 87 groundwater samples in Island and 112 groundwater samples in mainland which include pH, EC, TDS, salinity, total alkalinity, calcium hardness, magnesium hardness, total hardness, chloride and fluoride. Heavy inorganic load in majority of the groundwater samples has been estimated due to the salinity, TDS, TH and chloride beyond the threshold level which substantiates the percolation of sea water into the freshwater confined zones. Although the groundwater sources are available in plenty, the scarcity of potable water is most prevalent in this coastal area. The Water Quality Index (WQI) and Langeleir Saturation Index (LSI) have also been calculated to know the potable and corrosive/incrusting nature of the water samples. The statistical tools such as principal component analysis, box plots and correlation matrix have also been used to explain the influence of different physico-chemical parameters with respect to one another among the groundwater samples. The percentage of groundwater samples in mainland was more than that in Island with respect to the acceptable limit of WHO drinking standard, especially in TDS, CH, TH and chloride but the converse is observed in the case of fluoride. About 8% of the mainland aquifers and 42% of Island aquifers were identified to have fluoride greater than 1.5 mg/l. The signature of salt-water intrusion is observed from the ratio of Cl/CO(3)(2-) + HCO(3) and TA/TH. A proper management plan to cater potable water to the immediate needs of the people is to be envisaged.

  8. Urban heat island in southern Europe: The case study of Hania, Crete

    SciTech Connect

    Kolokotsa, D.; Psomas, A.; Karapidakis, E.

    2009-10-15

    The aim of the present paper is to analyze the results of the urban heat island research for a coastal densely built small Mediterranean town namely Hania, Crete, Greece. The specific research targets to verify the existence, the intensity, the size and the form of the urban heat island phenomenon in the specific region as well as to understand its correlation with the local weather conditions. Nine urban and three rural meteorological stations are used for this study. Temperature and relative humidity measurements are collected from May 26, 2007 until October 24, 2007. In parallel, meteorological data including wind speed and direction, barometric pressure, sunlight and precipitation for the specific region are collected and elaborated for cross-correlation with the appearance of the urban heat island (UHI) phenomenon. During summer period, where the temperature is high, the UHI takes its maximum intensity, of about 8 C. Also, the form of the UHI is strongly influenced from the wind speed and direction. The northern winds expand the UHI front, while the western winds contribute to the UHI reduction. Finally the Discomfort Index (DI) is calculated for the 2007 summer period to indicate the outdoor living conditions. (author)

  9. The northward tectonic transport in the southern Apennines: examples from the Capri Island and western Sorrento Peninsula (Italy)

    NASA Astrophysics Data System (ADS)

    Vitale, Stefano; Tramparulo, Francesco D'Assisi; Ciarcia, Sabatino; Amore, Filomena Ornella; Prinzi, Ernesto Paolo; Laiena, Fabio

    2017-01-01

    We analyzed a thrust fault system located in the western Sorrento Peninsula and Capri Island (southern Italy) where several mesoscale structures related to the main thrusts, such as Riedel shear planes, overturned folds, minor thrust and back-thrust faults, suggest a dominant northward tectonic transport. Major and minor thrust faults, generally characterized by a ramp-flat geometry, involved the Mesozoic Apennine carbonates, the Middle Miocene foredeep, and the unconformable thrust-top basin deposits. The biostratigraphic analysis of calcareous nannoplankton assemblages on the thrust-top basin sediments indicates an age not older than late Tortonian. We propose that this out-of-sequence thrusting stage was related to a regional tectonic event widespread in the entire southern Apennines, probably occurred in the Pliocene time simultaneously with the activity of deep-seated thrust faults that involved the buried carbonates of the Apulian platform. These out-of-sequence thrust faults, here referred to as "envelopment thrusts," were enucleated in a lower structural level with respect to the allochthonous wedge, representing the W-E segments of large regional arcuate structures.

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

    PubMed

    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.

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

    PubMed Central

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

    2012-01-01

    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. PMID:22378808

  12. Southern elephant seals from Kerguelen Islands confronted by Antarctic Sea ice. Changes in movements and in diving behaviour

    NASA Astrophysics Data System (ADS)

    Bailleul, Frédéric; Charrassin, Jean-Benoıˆt; Ezraty, Robert; Girard-Ardhuin, Fanny; McMahon, Clive R.; Field, Iain C.; Guinet, Christophe

    2007-02-01

    The behaviour of southern elephant seals from Kerguelen Island ( 49∘50'S, 70∘30'E) was investigated in relation to the oceanographic regions of the Southern Ocean. The oceanographic and the seal behaviour data, including location and diving activity, were collected using a new generation of satellite-relayed devices measuring and transmitting pressure, temperature, and salinity along with locations. Dive duration, maximum diving depth, time spent at the bottom of the dives, and shape of dive profiles were compared between male and female seals, and were related to the oceanographic characteristics of areas prospected by the seals. Most animals travelled to the Antarctic shelf. However, during winter, adult females travelled away from the continent, remained and foraged within the marginal sea-ice zone, while juvenile males remained within the pack ice to forage mainly on the Antarctic shelf. Therefore, as the ice expanded females appeared to shift from benthic to pelagic foraging farther north, while males continued to forage almost exclusively benthically on the continental shelf. This difference is likely related to the different energetic requirements between the two sexes, but also may be related to pregnant females having to return to Kerguelen in early spring in order to give birth and successfully raise their pups, while males can remain in the ice. Our results show an important link between elephant seals and Antarctic sea ice and suggest that changes in sea-ice conditions could strongly affect the behaviour of this species.

  13. Volcanic hazard and risk assessment from pyroclastic flows at Ischia island (southern Italy)

    NASA Astrophysics Data System (ADS)

    Alberico, Ines; Lirer, Lucio; Petrosino, Paola; Scandone, Roberto

    2008-03-01

    The areas exposed to pyroclastic flow invasion in case of explosive eruptions at Ischia island (Italy) have been evaluated, together with the related volcanic hazard and risk. Ischia island lacks a central vent so, for the evaluation of volcanic hazard, it is necessary to forecast where a future explosive event might occur. At this purpose, we have evaluated the Vent Opening Probability by taking into account all the relevant geological information and processing them through spatial analysis. The whole Ischia island has been subdivided into 358 cells, in which we take into account the contribution of volcanological, geophysical and geochemical data to define the probability of opening of the vents. As a result, the highest spatial probability is found on the eastern sector of the island. Two series of simulations, by using the "energy cone" model [Malin, M.C., Sheridan, M.F., 1982. Computer-assisted mapping of pyroclastic surges. Science 217, 637-640] and assuming column collapse heights of 100 m, for eruptions of Volcanic Explosivity Index (VEI) = 3, and of 300 m for eruptions of VEI = 4, with Heim coefficient equal to 0.1, were performed. Through the overlay of the energy cone to the Digital Elevation Model of Ischia, it has been possible to automatically detect the invaded areas for each hypothesized vent. The intersection of this areas made it possible to define the different spatial probabilities of invasion by pyroclastic flow (PyF) for each point of the Ischia territory. Two different types of hazard maps have been derived: an equi-probability hazard map, sensitive to the distance from the vents and the presence of topographic obstacles, and a weighted hazard map, in which the probability of vent opening has also been taken into account. For both types of eruptions, the highest spatial probability of invasion are the so-called "graben of Ischia", and the coastal plain between Monte Vico and Ischia Porto. Finally, by intersecting the exposed value map with

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

    PubMed

    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. Formation and Evolution of the San Cristobal Trough Transform Fault Linking the Southern Solomon Islands and Northern New Hebrides Trenches

    NASA Astrophysics Data System (ADS)

    Furlong, K. P.; Hayes, G. P.; Herman, M. W.; Benz, H.

    2014-12-01

    The San Cristobal Trough, which occupies the southern segment of the South Solomon Trench, hosts a dominantly left-lateral transform plate boundary (SCTF) linking the southern end of the Solomon Islands subduction zone (SISZ) to the northern end of the New Hebrides (Vanuatu) subduction zone (NHSZ). At its western end (SISZ), the Australia plate is torn as a result of the transition from subduction to transform motion. The southern side of the tear translates approximately 375 km along the SCTF before subducting beneath the Santa Cruz Islands at the NHSZ. Earthquakes occurring along this transform reflect the processes of plate tearing, fault zone evolution, and subsequent underthrusting and subduction of the Australia-plate-side of the transform. A knot of earthquake activity at the western end of the SCTF juxtaposes high-angle thrust faulting events with left-lateral strike slip events. These record the tearing of Australian lithosphere, as shown by a recent pair of large earthquakes in that region - a Mw 7.6 strike-slip event (12 April 2014) followed 22 hours later by a Mw 7.4 high-angle reverse faulting event (13 April 2014). Associated displacements reflect oblique tearing (northern-side down and west), allowing the Australia Plate to follow two disparate paths - subduction at the SISZ to the north and translation along the SCTF to the south. Moving eastward along the transform, the plate boundary shows three styles of earthquake activity. The main transform is dominated by shallow, E-W striking, left-lateral faulting and E-W striking thrust faults (with a north-dipping shallow fault plane) - these reflect partitioning of oblique motion along the transform between the Australia and Pacific plates. Outboard (+/- 100 km) of the plate boundary, a group of E-W striking shallow normal faulting events reflect upward bending driven by the convergent component of plate motions. Approaching the NHSZ, normal faulting earthquakes in the Australia Plate rotate clockwise

  16. FLANDERS FIELDS MEMORIAL IN TRAFFIC ISLAND ON EAST DRIVE. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FLANDERS FIELDS MEMORIAL IN TRAFFIC ISLAND ON EAST DRIVE. VIEW TO NORTHEAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

  17. Spatial and temporal patterns of carbon storage in forest ecosystems on Hainan island, southern China.

    PubMed

    Ren, Hai; Li, Linjun; Liu, Qiang; Wang, Xu; Li, Yide; Hui, Dafeng; Jian, Shuguang; Wang, Jun; Yang, Huai; Lu, Hongfang; Zhou, Guoyi; Tang, Xuli; Zhang, Qianmei; Wang, Dong; Yuan, Lianlian; Chen, Xubing

    2014-01-01

    Spatial and temporal patterns of carbon (C) storage in forest ecosystems significantly affect the terrestrial C budget, but such patterns are unclear in the forests in Hainan Province, the largest tropical island in China. Here, we estimated the spatial and temporal patterns of C storage from 1993-2008 in Hainan's forest ecosystems by combining our measured data with four consecutive national forest inventories data. Forest coverage increased from 20.7% in the 1950s to 56.4% in the 2010s. The average C density of 163.7 Mg C/ha in Hainan's forest ecosystems in this study was slightly higher than that of China's mainland forests, but was remarkably lower than that in the tropical forests worldwide. Total forest ecosystem C storage in Hainan increased from 109.51 Tg in 1993 to 279.17 Tg in 2008. Soil C accounted for more than 70% of total forest ecosystem C. The spatial distribution of forest C storage in Hainan was uneven, reflecting differences in land use change and forest management. The potential carbon sequestration of forest ecosystems was 77.3 Tg C if all forested lands were restored to natural tropical forests. To increase the C sequestration potential on Hainan Island, future forest management should focus on the conservation of natural forests, selection of tree species, planting of understory species, and implementation of sustainable practices.

  18. Spatial and Temporal Patterns of Carbon Storage in Forest Ecosystems on Hainan Island, Southern China

    PubMed Central

    Tang, Xuli; Zhang, Qianmei; Wang, Dong; Yuan, Lianlian; Chen, Xubing

    2014-01-01

    Spatial and temporal patterns of carbon (C) storage in forest ecosystems significantly affect the terrestrial C budget, but such patterns are unclear in the forests in Hainan Province, the largest tropical island in China. Here, we estimated the spatial and temporal patterns of C storage from 1993–2008 in Hainan's forest ecosystems by combining our measured data with four consecutive national forest inventories data. Forest coverage increased from 20.7% in the 1950s to 56.4% in the 2010s. The average C density of 163.7 Mg C/ha in Hainan's forest ecosystems in this study was slightly higher than that of China's mainland forests, but was remarkably lower than that in the tropical forests worldwide. Total forest ecosystem C storage in Hainan increased from 109.51 Tg in 1993 to 279.17 Tg in 2008. Soil C accounted for more than 70% of total forest ecosystem C. The spatial distribution of forest C storage in Hainan was uneven, reflecting differences in land use change and forest management. The potential carbon sequestration of forest ecosystems was 77.3 Tg C if all forested lands were restored to natural tropical forests. To increase the C sequestration potential on Hainan Island, future forest management should focus on the conservation of natural forests, selection of tree species, planting of understory species, and implementation of sustainable practices. PMID:25229628

  19. Mite dispersal among the Southern Ocean Islands and Antarctica before the last glacial maximum.

    PubMed

    Mortimer, E; Jansen van Vuuren, B; Lee, J E; Marshall, D J; Convey, P; Chown, S L

    2011-04-22

    It has long been maintained that the majority of terrestrial Antarctic species are relatively recent, post last glacial maximum, arrivals with perhaps a few microbial or protozoan taxa being substantially older. Recent studies have questioned this 'recolonization hypothesis', though the range of taxa examined has been limited. Here, we present the first large-scale study for mites, one of two dominant terrestrial arthropod groups in the region. Specifically, we provide a broad-scale molecular phylogeny of a biologically significant group of ameronothroid mites from across the maritime and sub-Antarctic regions. Applying different dating approaches, we show that divergences among the ameronothroid mite genera Podacarus, Alaskozetes and Halozetes significantly predate the Pleistocene and provide evidence of independent dispersals across the Antarctic Polar Front. Our data add to a growing body of evidence demonstrating that many taxa have survived glaciation of the Antarctic continent and the sub-Antarctic islands. Moreover, they also provide evidence of a relatively uncommon trend of dispersals from islands to continental mainlands. Within the ameronothroid mites, two distinct clades with specific habitat preferences (marine intertidal versus terrestrial/supralittoral) exist, supporting a model of within-habitat speciation rather than colonization from marine refugia to terrestrial habitats. The present results provide additional impetus for a search for terrestrial refugia in an area previously thought to have lacked ice-free ground during glacial maxima.

  20. Mite dispersal among the Southern Ocean Islands and Antarctica before the last glacial maximum

    PubMed Central

    Mortimer, E.; Jansen van Vuuren, B.; Lee, J. E.; Marshall, D. J.; Convey, P.; Chown, S. L.

    2011-01-01

    It has long been maintained that the majority of terrestrial Antarctic species are relatively recent, post last glacial maximum, arrivals with perhaps a few microbial or protozoan taxa being substantially older. Recent studies have questioned this ‘recolonization hypothesis’, though the range of taxa examined has been limited. Here, we present the first large-scale study for mites, one of two dominant terrestrial arthropod groups in the region. Specifically, we provide a broad-scale molecular phylogeny of a biologically significant group of ameronothroid mites from across the maritime and sub-Antarctic regions. Applying different dating approaches, we show that divergences among the ameronothroid mite genera Podacarus, Alaskozetes and Halozetes significantly predate the Pleistocene and provide evidence of independent dispersals across the Antarctic Polar Front. Our data add to a growing body of evidence demonstrating that many taxa have survived glaciation of the Antarctic continent and the sub-Antarctic islands. Moreover, they also provide evidence of a relatively uncommon trend of dispersals from islands to continental mainlands. Within the ameronothroid mites, two distinct clades with specific habitat preferences (marine intertidal versus terrestrial/supralittoral) exist, supporting a model of within-habitat speciation rather than colonization from marine refugia to terrestrial habitats. The present results provide additional impetus for a search for terrestrial refugia in an area previously thought to have lacked ice-free ground during glacial maxima. PMID:20943685

  1. Repeated Surveys and Historical Nautical Charts Support Elastic Rebound Model on Megathrust at Santa MARÍA Island, Chile, (37°S) Through One and One-Half Seismic Cycles

    NASA Astrophysics Data System (ADS)

    Wesson, R. L.; Melnick, D.; Cisternas, M.; Ely, L. L.; Moreno, M.

    2010-12-01

    Repeated bathymetric surveys, historical nautical charts, geologic observations, interviews with local residents, and modern GPS measurements all support a pattern of coseismic uplift, followed by post-seismic and inter-seismic subsidence, at Santa María Island off the coast of south-central Chile. The island is located approximately 75 km landward of the Chile trench and about 12 km above the megathrust fault. Six weeks after the February 20, 1835 Concepcion earthquake (~M 8.5), Captain Robert FitzRoy and the HMS Beagle visited the island and reported 2.4-3 m of uplift based primarily on observations of elevated, newly dead, intratidal and subtidal shellfish attached to rocks. The February 27, 2010 Maule earthquake (M 8.8) earthquake produced similar effects. Several lines of evidence suggest significant subsidence between 1835 and 2010. First, the extensive wave-cut platform at the northern end of island that FitzRoy vividly describes as being exposed and covered with dead shellfish in 1835, lay at the lower level of the island’s 2-m tidal range in January 2010. The nautical chart prepared by officers of the Beagle suggests that the platform was above high tide in 1835. An elderly resident reports that in the first half of the twentieth century part of the platform was above high tide. While some lowering of the bedrock platform could be explained by erosion, the amount of required erosion would be very rapid and extensive. GPS measurements for the interval 2004-2008 indicate that the island subsided at a rate of 10 +/- 1 mm/a as well as moving landward at a rate of 42 mm/a. On January 13 and 15, 2010, we carried out a simple echo-sounder survey in the bay off the southeastern coast of Santa María Island. The same bay, Rada Santa Maria, was surveyed by the Beagle in 1835 using a lead line and pole. The bay has a smooth and very gently sloping bottom, an average depth of about 8 m, and dimensions of about 3 x 5 km. Comparison of our measured depths with those

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

    NASA Astrophysics Data System (ADS)

    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 <1 mmol C m-2 d-1). It appears that nitrate is assimilated in the upper part of the mixed layer (coinciding with the euphotic layer) and regenerated in the lower parts. We suggest that such high contribution of nitrification to nitrate assimilation is driven by (i) a deep mixed layer, extending well below the euphotic layer, allowing nitrifiers to compete with phytoplankton for the assimilation of ammonium, (ii) extremely high rates of primary production for the Southern Ocean, stimulating the release of dissolved 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.

  3. Temporal evolution of a three component system: the island of Lipari (Aeolian Arc, southern Italy)

    NASA Astrophysics Data System (ADS)

    Crisci, G. M.; de Rosa, R.; Esperança, S.; Mazzuoli, R.; Sonnino, M.

    1991-04-01

    The volcanic products from Lipari define an evolutionary trend with a high gradient of K-enrichment, similar to the calc-alkaline to potassic volcanism of other islands in the Aeolian arc. Stratigraphic reconstruction of the island based on field and geochronological data indicate that the volcanic activity can be subdivided in two stages. The first stage, from 223 to 42 ka, consists of six eruptive cycles and is characterized by basalts and basalt-andesites showing progressive increase in both SiO2 and K2O contents with time. The second stage consists of four cycles erupted since 42 ka and is marked by an apparent rejuvenation of the geochemical system with the appearance of the first rhyolitic products. Fractional crystallization, assimilation and mixing models suggest that the geochemistry of Lipari volcanism evolved with time by a complex interplay between two mantle-derived components, one sub-alkaline and the other alkaline, in addition to crustal melts and/or crustally-derived materials. A petrogenetic model in which fractional crystallization was subordinate to mixing best fits the geochemical data and petrographic observations of macro- and microscopic features. Melts from the crustal and mantle end-members are almost always present in the system but the relative proportions appear to vary with time. The sub-alkaline mantle component (source of Tyrrhenian tholeiites) is an important contributor to the early evolution of the volcanism in Lipari; input from the alkaline mantle component (source of the Roman Comagmatic Province) increases with time, and the crustal component becomes dominant in the later activity. The preferred petrogenetic model for the temporal evolution of the volcanic system in Lipari involves melting initially caused by an increase in the thermal input related to the opening of the Tyrrhenian Sea and/or to subduction processes. The quick rise of the isotherms and almost contemporaneous melting of source materials with different

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Physical, chemical and mineralogical evolution of the Tolhuaca geothermal system, southern Andes, Chile: Insights into the interplay between hydrothermal alteration and brittle deformation

    NASA Astrophysics Data System (ADS)

    Sanchez-Alfaro, Pablo; Reich, Martin; Arancibia, Gloria; Pérez-Flores, Pamela; Cembrano, José; Driesner, Thomas; Lizama, Martin; Rowland, Julie; Morata, Diego; Heinrich, Christoph A.; Tardani, Daniele; Campos, Eduardo

    2016-09-01

    In this study, we unravel the physical, chemical and mineralogical evolution of the active Tolhuaca geothermal system in the Andes of southern Chile. We used temperature measurements in the deep wells and geochemical analyses of borehole fluid samples to constrain present-day fluid conditions. In addition, we reconstructed the paleo-fluid temperatures and chemistry from microthermometry and LA-ICP-MS analysis of fluid inclusions taken from well-constrained parageneses in vein samples retrieved from a ~ 1000 m borehole core. Based on core logging, mineralogical observations and fluid inclusions data we identify four stages (S1-S4) of progressive hydrothermal alteration. An early heating event (S1) was followed by the formation of a clay-rich cap in the upper zone (< 670 m) and the development of a propylitic alteration assemblage at greater depth (S2). Boiling, flashing and brecciation occurred later (S3), followed by a final phase of fluid mixing and boiling (S4). The evolution of hydrothermal alteration at Tolhuaca has produced a mineralogical, hydrological and structural vertical segmentation of the system through the development of a low-permeability, low-cohesion clay-rich cap at shallow depth. The quantitative chemical analyses of fluid inclusions and borehole fluids reveal a significant change in chemical conditions during the evolution of Tolhuaca. Whereas borehole (present-day) fluids are rich in Au, B and As, but Cu-poor (B/Na ~ 100.5, As/Na ~ 10- 1.1, Cu/Na ~ 10- 4.2), the paleofluids trapped in fluid inclusions are Cu-rich but poor in B and As (B/Na ~ 10- 1, As/Na ~ 10- 2.5, Cu/Na ~ 10- 2.5 in average). We interpret the fluctuations in fluid chemistry at Tolhuaca as the result of transient supply of metal-rich, magmatically derived fluids where As, Au and Cu are geochemically decoupled. Since these fluctuating physical and chemical conditions at the reservoir produced a mineralogical vertical segmentation of the system that affects the mechanical and

  6. The Influence of Shear-Thinning and Crustal Yield Strength on Lava Flow Evolution: a Case Study from Volcanoes of the Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Castruccio, A.; Contreras, M.; Gho, R.

    2013-12-01

    Lava flow modeling is a complex challenge as the advance and emplacement of these flows is controlled by parameters that are constantly evolving such as the effusion rate, topography, rheology and cooling effects. Current models of lava flows use a Bingham rheology and assume that the main retarding force is the internal rheology that is changing downstream and trough time due to cooling effects. However, field evidence from active lava flows and the resulting deposits indicates that an external crust forms due to cooling processes. Very few works have addressed the influence of the crust on the dynamics and advance rate of lava flows but increasing evidence suggests that it cannot be neglected. On the other hand, numerous works during the last decade has shown that crystal-bearing magmas have a complex rheology with a strain-rate dependence on viscosity and consequently, the Bingham model can represent accurately the rheology of lava only over a limited range of conditions. In this work we studied the lava flow evolution and deposits of several historical eruptions from Villarrica (2 cases), Llaima, Mirador, Calbuco and Lonquimay volcanoes in the Southern Andes of Chile. We used a simple 2-D model that simulates the evolution of the front of the flow that is being fed by lava pouring down from a fixed-wall channel at the back of the frontal zone. We used a Herschel-Bulkley rheology as it captures yield strength and shear-thinning behavior. We also included in the analysis the evolution of a set of well-documented eruptions from Hawaii and Etna using published data. Our results indicate that short-lived eruptions, with effusion rates greater than 100 m^3/s that last only a couple of days are controlled by an almost constant rheology of the front as the apparent increasing in viscosity through time can be explained by the shear-thinning behavior, because when effusion rate decreases, the velocity and consequently the strain-rate of the flow decreases, implying an

  7. Using U-series and beryllium isotopes to reveal the occurrence and relative timing of crustal and mantle processes in the Southern Volcanic Zone of Chile

    NASA Astrophysics Data System (ADS)

    Cooper, L. B.; Reubi, O.; Dungan, M. A.; Bourdon, B.; Langmuir, C. H.; Turner, S. J.; Schaefer, J. M.

    2012-12-01

    Magmas erupted from subduction zone volcanoes represent the end products of multiple magmatic processes occurring in the asthenospheric mantle wedge and overlying lithosphere (i.e., fluid addition, melting, assimilation, and crystal fractionation). To resolve the contributions of diverse processes and components, and the relative timing of these events, we have determined U-series activities (U-Th-Ra-Pa) for 60 and 10Be compositions for 20 historic or very young lavas carefully chosen on the basis of major and trace element analyses of 625 samples from six volcanoes in the Andean Southern Volcanic Zone of Chile (37.6-41.1°S: Nevados de Chillán, Antuco, Llaima, Lonquimay, Villarrica, and Osorno). Our dataset demonstrates that each of these volcanoes reflects a unique combination and sequence of magmatic processes that are only revealed through analysis of multiple samples spanning the extent of intra-volcano and intra-eruption chemical variation. Sigmarsson et al. (1990; 2002) identified a regional trend using U-series and Be from mostly single samples, which they interpreted to represent along-strike variations in the flux of slab-derived fluids into the wedge [from 230Th-excess plus 226Ra-deficit plus low 10Be/9Be at Chillán towards progressively higher 238U- and Ra-excesses and 10Be/9Be at Villarrica and Osorno]. These data fall within the much broader array defined by our results, but we infer the operation of assimilation (e.g., Llaima; Reubi et al., 2011) and aging of subduction zone components of variable compositions and proportions in the mantle prior to partial melting as important factors in generating the highly individualized and complex U-series systematics observed at each of these six volcanoes. All of the volcanoes exhibit evidence of assimilation, with the exception of Lonquimay which has undergone mostly closed-system fractional crystallization. At Llaima and Chillán the assimilant is crustal. At Villarica, flux-related melts that dominate in

  8. Isotopic compositions of volcanic arc rocks in the Southern Volcanic Zone (33°-43°S), Chile: along- and across-arc variations

    NASA Astrophysics Data System (ADS)

    Jacques, Guillaume; Hoernle, Kaj; Gill, Jim; Wehrmann, Heidi

    2014-05-01

    We investigate young, olivine-bearing volcanic arc (VA) rocks from the Southern Volcanic Zone (33-43°S; SVZ) in Chile, and from the backarc (BA) in Argentina for their major and trace element, and Sr-Nd-Hf-Pb-O isotope geochemistry. The compositional data are processed to identify the source components contributing to the arc magmas and to estimate their proportions, with the aim to better understand the effects of the large-scale along-arc tectonic variations onto melt generation and erupted compositions. The Transitional (T) SVZ (34.5-38°S; Jacques et al., 2013) samples overlap the BA samples in Sr and Nd isotopes, whereas the Central (C) SVZ (38-43°S; Jacques et al., submitted, Chemical Geology) samples are shifted to slightly higher Sr and/or Nd isotope ratios. All samples form a tight correlation on the Pb isotope diagrams. The VA samples plot at the radiogenic end of the positive BA array and overlap trench sediment, indicating mixing between a South Atlantic MORB-type source and a slab component derived from subducted trench sediments and altered oceanic crust. On the Nd versus Hf isotope diagram, the VA and BA form two sub parallel linear trends, neither pointing to subducting sediment. The VA may display an asthenospheric mantle array, whereas enriched Proterozoic lithospheric mantle may be involved in the BA. The CSVZ samples have higher fluid-mobile to fluid-immobile element ratios and lower more- to less-incompatible fluid-immobile element ratios than the TSVZ samples, consistent with higher hydrous melt flux and higher degrees of melting resulting in higher magma production and eruption rates in the CSVZ. Low δ18O(melt) of CSVZ lavas suggests that the source of the enhanced water flux is likely to be hydrated lower crust and serpentinized upper mantle of the incoming plate, resulting from the multiple large fracture zones in this part of the SVZ. The δ18O(melt) values of the NSVZ, TSVZ and BA, on the other hand, largely overlap the MORB mantle

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Determinants and geographical variation in the distribution of depression in the Southern cone of Latin America: A population-based survey in four cities in Argentina, Chile and Uruguay.

    PubMed

    Daray, F M; Rubinstein, A L; Gutierrez, L; Lanas, F; Mores, N; Calandrelli, M; Poggio, R; Ponzo, J; Irazola, V E

    2017-10-01

    Depression is one of the major contributors to the global burden of diseases; however, population-based data in South America are limited. We conducted a population-based cross sectional study with 7524 participants, aged 35-74 years old, recruited between February 2010 and December 2011 from randomly selected samples in 4 cities (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay). Major Depressive Episode (MDE) was assessed using the Patient Health Questionnaire (PHQ) - 9. The overall prevalence of MDE was 14.6% (95% CI: 13.6, 15.6). However, there was a geographical variability of up to 3.7 folds between different cities being 5.6% (95% CI: 4.6, 6.7) in Marcos Paz, Argentina; 9.5% (95% CI: 8.2, 10.9) in Bariloche, Argentina; 18.1% (95% CI: 16.3, 20.0) in Temuco, Chile, and 18.2 (95% CI: 16.3, 20.2) in Pando-Barros Blancos, Uruguay. The multivariate model showed that, adjusted by location, being female, being between 35 and 44 years old, having experienced at least one stressful life event, currently smoking, and having a history of chronic medical diseases were independently associated with an increased risk of MDE, while having higher education and being married or living with a partner reduced the risk of MDE. These results are representative of the selected cities included in the study. As such extrapolation to the general populations of Argentina, Chile, and Uruguay should be done with caution CONCLUSIONS: This study showed a high prevalence and variability of MDE in the Southern Cone of Latin America. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Gamma-ray activity in the volcanic islands of the Southern Tyrrhenian Sea.

    PubMed

    Chiozzi, P; Pasquale, V; Verdoya, M; Minato, S

    2003-01-01

    Field gamma-ray spectrometry was used for the quantitative assessment of U, Th and K of rocks of Stromboli, Salina, Filicuidi and Panarea (Aeolian arc of the Southern Tyrrhenian, Italy). The air absorbed dose rate was calculated from radioelement concentrations. For some rocks the gamma-ray spectra were analysed with the three photo-peak methods and the response matrix method, which converts the pulse height distribution into the true incident gamma-ray energy spectrum. The higher values of U (8.2-9.8 ppm) coincide with higher Th (20.6-27.8 ppm) concentrations associated with rocks of shoshonitic composition. The spatial variation in radioelement concentration reflects the geochemical differences among the rocks. The air absorbed dose rate varies from 25 to 215 nGy h(-1). The highest values correspond to outcrops located in the eastern part of Stromboli, where the annual effective dose equivalent reaches a value of 264 microSv.

  12. Mid-Pleistocene cosmogenic minimum-age limits for pre-Wisconsinan glacial surfaces in southwestern Minnesota and southern Baffin Island: A multiple nuclide approach

    USGS Publications Warehouse

    Bierman, P.R.; Marsella, K.A.; Patterson, Chris; Davis, P.T.; Caffee, M.

    1999-01-01

    Paired 10Be and 26Al analyses (n = 14) indicate that pre-Wisconsinan, glaciated bedrock surfaces near the northern (Baffin Island) and southern (Minnesota) paleo-margins of the Laurentide Ice Sheet have long and complex histories of cosmic-ray exposure, including significant periods of partial or complete shielding from cosmic rays. Using the ratio, 26Al/10Be, we calculate that striated outcrops of Sioux Quartzite in southwestern Minnesota (southern margin) were last overrun by ice at least 500,000 years ago. Weathered bedrock tors on the once-glaciated uplands of Baffin Island (northern margin) are eroding no faster than 1.1 m Myr-1, the equivalent of at least 450,000 years of surface and near-surface exposure. Our data demonstrate that exposure ages and erosion rates calculated from single nuclides can underestimate surface stability dramatically because any intermittent burial, and the resultant lowering of nuclide production rates and nuclide abundances, will remain undetected.

  13. Geochemistry of southern Pagan Island lavas, Mariana arc: The role of subduction zone processes

    USGS Publications Warehouse

    Marske, J.P.; Pietruszka, A.J.; Trusdell, F.A.; Garcia, M.O.

    2011-01-01

    New major and trace element abundances, and Pb, Sr, and Nd isotopic ratios of Quaternary lavas from two adjacent volcanoes (South Pagan and the Central Volcanic Region, or CVR) located on Pagan Island allow us to investigate the mantle source (i.e., slab components) and melting dynamics within the Mariana intra-oceanic arc. Geologic mapping reveals a pre-caldera (780-9.4ka) and post-caldera (<9.4ka) eruptive stage for South Pagan, whereas the eruptive history of the older CVR is poorly constrained. Crystal fractionation and magma mixing were important crustal processes for lavas from both volcanoes. Geochemical and isotopic variations indicate that South Pagan and CVR lavas, and lavas from the northern volcano on the island, Mt. Pagan, originated from compositionally distinct parental magmas due to variations in slab contributions (sediment and aqueous fluid) to the mantle wedge and the extent of mantle partial melting. A mixing model based on Pb and Nd isotopic ratios suggests that the average amount of sediment in the source of CVR (~2.1%) and South Pagan (~1.8%) lavas is slightly higher than Mt. Pagan (~1.4%) lavas. These estimates span the range of sediment-poor Guguan (~1.3%) and sediment-rich Agrigan (~2.0%) lavas for the Mariana arc. Melt modeling demonstrates that the saucer-shaped normalized rare earth element (REE) patterns observed in Pagan lavas can arise from partial melting of a mixed source of depleted mantle and enriched sediment, and do not require amphibole interaction or fractionation to depress the middle REE abundances of the lavas. The modeled degree of mantle partial melting for Agrigan (2-5%), Pagan (3-7%), and Guguan (9-15%) lavas correlates with indicators of fluid addition (e.g., Ba/Th). This relationship suggests that the fluid flux to the mantle wedge is the dominant control on the extent of partial melting beneath Mariana arc volcanoes. A decrease in the amount of fluid addition (lower Ba/Th) and extent of melting (higher Sm/Yb), and

  14. Three-dimensional resistivity tomography of Vulcan's forge, Vulcano Island, southern Italy

    NASA Astrophysics Data System (ADS)

    Revil, A.; Johnson, T. C.; Finizola, A.

    2010-08-01

    9,525 DC resistivity measurements were taken along 9 profiles crossing the volcanic edifice of La Fossa di Vulcano (the forge of God Vulcan in ancient Roman mythology), Vulcano Island (Italy) using a total of 958 electrode locations. This unique data set has been inverted in 3D by minimizing the L2 norm of the data misfit using a Gauss-Newton approach. The true 3D inversion was performed using parallel processing on an unstructured tetrahedral mesh containing 75,549 finite-element nodes and 398,208 elements to accurately model the topography of the volcanic edifice. The 3D tomogram shows a very conductive body (>0.1 S/m) comprised inside the Pietre Cotte crater with conductive volumes that are consistent with the position of temperature and CO2 anomalies at the ground surface. This conductive body is interpreted as the main hydrothermal body. It is overlaid by a resistive and cold cap in the bottom of the crater. The position of the conductive body is consistent with the deformation source responsible for the observed 1990-1996 deflation of the volcano associated with a decrease of hydrothermal activity.

  15. Glassy fragmental rocks of Macquarie Island (Southern Ocean): Mechanism of formation and deposition

    NASA Astrophysics Data System (ADS)

    Dickinson, J. A.; Harb, N.; Portner, R. A.; Daczko, N. R.

    2009-04-01

    Glassy fragmental rocks are interlayered with pillow basalt and tabular basalt on Macquarie Island (54°30' S, 158°54' E). These facies formed along the Proto-Macquarie Spreading Ridge between 6 and 12 Ma and have since been uplifted and exposed on the apex of the Macquarie Ridge Complex. Through a combination of field and microscopic analyses, we investigate the submarine production, transportation, deposition and lithification of basalt and sideromelane clasts within a spreading-ridge environment. The findings of this study indicate that these glassy grains form predominantly by cooling-contraction granulation of pillow lava rinds while crystalline basalt clasts are derived from the fragmentation of pillows along concentric and radial cooling joints. Hyaloclastite breccias consist of crystalline volcanic clasts in a matrix of glassy fragments, and are termed pillow-fragment breccias when clasts identifiable as pillows account for > 25% of the cobble-sized fraction. This glassy fragmental sediment was transported predominantly by short-lived grain flows and deposited as a result of syn-eruptive talus accumulation. The above interpretations culminate in the production of a depositional model: these glassy fragmental rocks formed on the slopes of pillow cones following gravitational collapse of a destabilised cone flank along the Proto-Macquarie Spreading Ridge. Scanning electron microscopy reveals that palagonite alteration rims on glassy grains lithify the sediment. The findings may be used as an analogue for the formation of glassy fragmental rocks along past and present mid-oceanic ridges.

  16. The relative abundance of dimethylsulfoniopropionate (DMSP) among other zwitterions in branching coral at Heron Island, southern Great Barrier Reef.

    PubMed

    Swan, Hilton B; Deschaseaux, Elisabeth S M; Jones, Graham B; Eyre, Bradley D

    2017-07-01

    Dimethylsulfoniopropionate (DMSP) and eleven other target zwitterions were quantified in the branch tips of six Acropora species and Stylophora pistillata hard coral growing on the reef flat surrounding Heron Island in the southern Great Barrier Reef (GBR), Australia. Hydrophilic interaction liquid chromatography mass spectrometry (HILIC-MS) was used for sample analysis with isotope dilution MS applied to quantify DMSP. The concentration of DMSP was ten times greater in A. aspera than A. valida, with this difference being maintained throughout the spring, summer and winter seasons. In contrast, glycine betaine was present in significantly higher concentrations in these species during the summer than the winter. Exposure of branch tips of A. aspera to air and hypo-saline seawater for up to 1 h did not alter the concentrations of DMSP present in the coral when compared with control samples. DMSP was the most abundant target zwitterion in the six Acropora species examined, ranging from 44-78% of all target zwitterions in A. millepora and A. aspera, respectively. In contrast, DMSP only accounted for 7% in S. pistillata, with glycine betaine and stachydrine collectively accounting for 88% of all target zwitterions in this species. The abundance of DMSP in the six Acropora species examined points to Acropora coral being an important source for the biogeochemical cycling of sulfur throughout the GBR, since this reef-building branching coral dominates the coral cover of the GBR. Graphical Abstract HILIC-MS extracted ion chromatogram showing zwitterionic metabolites from the branching coral Acropora isopora.

  17. Geology of the "20-foot" clay and Gardiners clay in southern Nassau and southwestern Suffolk counties, Long Island, New York

    USGS Publications Warehouse

    Doriski, T.P.; Wilde-Katz, Franceska

    1983-01-01

    Data from 1978-79 drilling was compiled with information from previous reports and historical records to prepare surface contour and isopach maps of the ' 20-foot ' clay and Gardiners Clay in southern Nassau and southwestern Suffolk Counties. These units are major confining layers in the upper part of the groundwater reservoir along Long Island 's south shore. Where present, they influence the groundwater flow patterns locally. The ' 20-foot ' clay, previously mapped in Nassau County only, was found in test borings in Suffolk County also. Its surface altitude ranges from 20 to 40 ft below NGVD (National Geodetic Vertical Datum of 1929); thickness ranges from 0 to 30 ft. The surface altitude of the Gardiners Clay ranges from 40 to 120 ft below NGVD; thickness ranges from 0 to 90 ft. Previously known discontinuities in both formations are more accurately delineated, and several new discontinuities have been inferred from the new data. The Matawan Group-Magothy Formation undifferentiated the Monmouth Group, and the Jameco Gravel directly underlie the Gardiners Clay. Revised surface altitudes of these formations are depicted on maps and cross sections of the south-shore area. (Author 's abstract)

  18. HLA genes of Aleutian Islanders living between Alaska (USA) and Kamchatka (Russia) suggest a possible southern Siberia origin.

    PubMed

    Moscoso, Juan; Crawford, Michael H; Vicario, Jose L; Zlojutro, Mark; Serrano-Vela, Juan I; Reguera, Raquel; Arnaiz-Villena, Antonio

    2008-02-01

    Aleuts HLA profile has been compared with that of neighboring and worldwide populations. Thirteen thousand one hundred and sixty-four chromosomes have been used for this study. Computer programs have obtained HLA allele frequencies, genetic distances between populations, NJ relatedness dendrograms, correspondence analysis and most frequent HLA extended haplotypes. Aleuts have inhabited Aleutian Islands since about 9000 years BP according to fossil and genetic (mtDNA) records. They are genetically different to Eskimo, Amerindian and Na-Dene speakers according to their HLA profile; this correlates with cultural and anthropological Aleut distinctiveness. No typical Amerindian HLA alleles have been found in a significant frequency. Their HLA relatedness to Saami (or Lapps, northern Scandinavians), Finns and Pomors (North-West Russia) indicates an ancient possible origin from the Baikal Lake Area (southern Siberia) around the present day Buryat peopling area; other origins are not discarded. Aleuts characteristic HLA profile may influence future transplantation programs in the region and be useful to study diseases linked to HLA epidemiology.

  19. Low-Frequency Earthquakes of the Southern Alps, South Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Chamberlain, C. J.; Shelly, D. R.; Townend, J.; Stern, T. A.

    2013-12-01

    Seismic tremor has a key role to play in our understanding of deep tectonic stresses and the transferal of these stresses to the shallow seismogenic crust. Documentation of tremor on the San Andreas Fault and the Alpine Fault provides new insight into the vertical extent of brittle behavior and ambient stress conditions near continental transform faults. Here we extend the previous analysis of tremor on the Alpine Fault, a ~600 km-long, dextral-reverse, transform fault forming the western boundary of the Southern Alps of New Zealand by documenting and locating low-frequency earthquakes (LFEs). We have initially focused on recognized periods of Alpine Fault tremor reported by Wech et al. (2012), using data from the Southern Alps Microearthquake Borehole Array (SAMBA; Boese et al., 2012) and the national seismic network, GeoNet. To identify LFEs, we use data from all stations at which tremor has been detected and require a minimum of five stations to show an LFE for it to be considered a reliable detection. In the first stage of the analysis, we identify LFE template events visually and locate these template events; we then apply a cross-correlation routine similar to that used for LFE detection in Japan and California (Shelly et al., 2009) in order to detect additional events and construct a homogeneous catalog. Due to the relatively large source-receiver and inter-station spacings (c. 20-100 km), we assume a LFE hypocenter near that of the corresponding template event and compute station delay factors. Using these delays, we then apply a finer cross-correlation routine to individual LFEs and locate these relative to the template event. The station distribution provided by SAMBA and GeoNet is not optimal for LFE detection, as all stations are situated north of the previously reported tremor locations. Nevertheless, our ability to identify LFEs on multiple, distant stations (>50 km epicentral distances) is promising for future investigations incorporating data from

  20. Methane at Ascension Island, southern tropical Atlantic Ocean: continuous ground measurement and vertical profiling above the Trade-Wind Inversion

    NASA Astrophysics Data System (ADS)

    Lowry, David; Brownlow, Rebecca; Fisher, Rebecca; Nisbet, Euan; Lanoisellé, Mathias; France, James; Thomas, Rick; Mackenzie, Rob; Richardson, Tom; Greatwood, Colin; Freer, Jim; Cain, Michelle; Warwick, Nicola; Pyle, John

    2015-04-01

    Methane mixing ratios have been rising rapidly worldwide since 2007. At Ascension Island (8oS in the equatorial Atlantic), a sustained rise has occurred. Prior to 2010, growth was comparable to other regions, but in 2010-11, during a strong la Nina event, the increase was 10ppb year-on-year. Reduced growth followed in 2011-12, but in 2012-13 strong growth resumed and continues. This rise has been accompanied by a shift to lighter δ13CCH4 values in 2010-11 in the equatorial tropics. The most likely cause of this shift is emissions from isotopically 'light' biological sources in the equatorial and savanna tropics. Ascension Island is in the Trade Wind belt of the tropical Atlantic, perfectly located to measure the South Atlantic marine boundary layer. The SE Trade Winds are almost invariant, derived from the deep South Atlantic and with little contact with Africa. However, above the Trade Wind Inversion (TWI) at about 1200-2000m asl, the air masses are very different, coming dominantly from tropical Africa and occasionally S. America. Depending on season, air above the TWI is sourced from the African southern savanna grasslands or the equatorial wetlands of Congo and Uganda, with inputs of air also from southern tropical S. America (Brazil, Paraguay, Bolivia). African methane sources are a major contributor to the global methane budget, but although local campaign studies have been made, African emissions are not well studied in bulk. In September 2014, an octocopter was used to retrieve air samples from heights up to 2700m asl on Ascension (see Thomas, R. et al, this volume). This allowed sampling through the marine boundary layer, across the TWI cloud layer, and into the mid-troposphere. Samples were collected in part-filled 5L Tedlar bags, which were analysed for CH4 concentration using Royal Holloway's Picarro 1301 CRDS system at the Met Office, Ascension. This has high precision and accuracy, with a 6-gas calibration suite. Bags were then analysed in the UK for

  1. Flux of low salinity water from Aniva Bay (Sakhalin Island) to the southern Okhotsk Sea

    NASA Astrophysics Data System (ADS)

    Oguma, Sachiko; Ono, Tsuneo; Watanabe, Yutaka W.; Kasai, Hiromi; Watanabe, Shuichi; Nomura, Daiki; Mitsudera, Humio

    2011-01-01

    In this study, we examined the relationship between the low salinity water in the shelf region of the southern Okhotsk Sea which was seasonally sampled (0-200 m), and fluxes of low salinity water from Aniva Bay. To express the source of freshwater mixing in the surface layer, we applied normalized total alkalinity (NTA) and stable isotopes of seawater as chemical tracers. NTA-S diagrams indicate that NTA of low salinity water in the upper 30 m layer just off the Soya Warm Current is clearly higher than in the far offshore region in summer and autumn. Using NTA-S regression lines, we could deduce that the low salinity and high NTA water in the upper layer originates from Aniva Bay. For convenience, we defined this water as the Aniva Surface Water (ASW) with values S < 32, NTA > 2450 μmol kg -1. Formation and transport processes of ASW are discussed using historical data. The interaction between the maximum core of high NTA water on the bottom slope of eastern Aniva Bay and an anticyclonic eddy at the mouth of Aniva Bay are concluded to control ASW formation. Upwelling of the Cold Water Belt water at the tip of Cape Krillion is considered to cause ASW outflow from Aniva Bay.

  2. Analysis of three tests of the unconfined aquifer in southern Nassau County, Long Island, New York

    USGS Publications Warehouse

    Lindner, J.B.; Reilly, T.E.

    1982-01-01

    Drawdown and recovery data from three 2-day aquifer tests (OF) the unconfined (water-table) aquifer in southern Nassau County, N.Y., during the fall of 1979, were analyzed. Several simple analytical solutions, a typecurve-matching procedure, and a Galerkin finite-element radial-flow model were used to determine hydraulic conductivity, ratio of horizontal to vertical hydraulic conductivity, and specific yield. Results of the curve-matching procedure covered a broad range of values that could be narrowed through consideration of data from other sources such as published reports, drillers ' logs, or values determined by analytical solutions. Analysis by the radial-flow model was preferred because it allows for vertical variability in aquifer properties and solves the system for all observation points simultaneously, whereas the other techniques treat the aquifer as homogeneous and must treat each observation well separately. All methods produced fairly consistent results. The ranges of aquifer values at the three sites were: horizontal hydraulic conductivity, 140 to 380 feet per day; transmissivity 11,200 to 17,100 feet squared per day; ratio of horizontal to vertical hydraulic conductivity 2.4:1 to 7:1, and specific yield , 0.13 to 0.23. (USGS)

  3. Fine-scale fault structures revealed by earthquake relocations near the Leech River Fault, southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Li, G.; Liu, Y.; Regalla, C.; Morell, K. D.

    2016-12-01

    We present results of microseismic relocations that delineate potentially seismogenic structures along the Leech River Fault (LRF), southern Vancouver Island. The potential seismic activity of the LRF in particular has been the focus of many recent investigations, given its proximity to Victoria, the capitol of British Columbia. We investigate the seismic evidence of subsurface structures near the LRF by relocating 1528 earthquakes reported by Canadian National Seismograph Network (CNSN) catalog from 1985 to 2015 using the HypoDD [Waldhauser, F., 2001] method. This relocation procedure reveals two general northeast dipping structures representing the subsurface fractured deformation zone beneath the LRF and the San Juan Islands area, respectively. The subsurface structure underlying the LRF extends about 30 km along the LRF strike and has a dip of about 45o, which is generally consistent with fault dip inferred from seismic imaging [Green et al., 1987]. In addition, we use the k-mean++ clustering algorithm [Lloyd, 1982; Arthur et al., 2007] to select 5-subclusters for individual relocations in order to investigate possible finer faulting structures. The relocated sub-cluster seismicity, combined with earthquake focal mechanism solutions from previous studies, delineates the subsurface geometry of minor faults near the LRF. Relocation results also show the eastern segment is seismically active while the western segment lacks seismicity. We suggest two potential explanations for this marked variation in seismic behavior. First, seismicity might reflect variations in the regionals tress field [Balfour et al., 2011]. The orientation of the maximum horizontal compressive stress near the LRF is 10-30° clockwise from the strike of eastern segment, which would promote right lateral slip, but is nearly orthogonal to the strike of the western segment, which would inhibit slip. Second, foliations and mylonitic fabric are generally stronger, more developed, and exist over a

  4. Ancient Geographical Gaps and Paleo-Climate Shape the Phylogeography of an Endemic Bird in the Sky Islands of Southern India

    PubMed Central

    Robin, V. V.; Sinha, Anindya; Ramakrishnan, Uma

    2010-01-01

    Background Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies. Methods and Principal Findings We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used Bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp) obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species. Conclusions and Significance Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have

  5. Asymmetrically multi-collapsed structure of Kikai caldera in southern off Kyushu Island, Japan: A reconstruction from seismic reflection images

    NASA Astrophysics Data System (ADS)

    Ikegami, F.; Kiyokawa, S.; Oiwane, H.; Nakamura, Y.; Kameo, K.; Minowa, Y.; Kuratomi, T.

    2012-12-01

    Kikai caldera (Matsumoto, 1943) is a mostly submerged highly active caldera complex located in the southern Japan 40 km off Kyushu Island. The caldera has bathymetrically two rims partially that are previously considered as older-outer and newer-inner ones (Yokoyama et al., 1966). The caldera is believed to be the source of Akahoya tephra (Machida and Arai, 1978) which date was determined as 7300 cal. BP (Fukusawa, 1995) which is the most recent VEI-7 class eruption in the eastern margin of Asia. Intense earthquakes (Naruo and Kobayashi, 2002), low-aspect ratio Koya ignimbrite (Maeno and Taniguchi, 2007) and tsunami (Geshi, 2009) are presumed to have taken place at the climax of the eruption. There are at least two other series of giant eruption deposits that are considered to have originated from the Kikai caldera (Ono et al., 1986) and this indicates that it has been serving as an eruptive center for the past 150,000 years. We conducted seismic reflection observations in two survey cruises (KT-10-18 and KT-11-11) in 2010 and 2011 using a research vessel Tansei-maru of JAMSTEC (Japan Agency for Marine-Earth Science and Technology). The sound source was a 150 cubic inches G-I gun with 10 seconds of shot interval, and a 48-channled streamer cable was used for acquisition. Totally 24 profiles were obtained with the speed of 4 knots. First, the absence of large fault in northern and western caldera rim indicates Kikai likely had an asymmetric "trapdoor" style collapse (Lipman, 1995) rather than the ideal "piston" type one. Inner and outer topographic rims at the east to south do correspond with large faults, however the both of them may have worked in 7300 BP eruption because they reach to the seafloor. Such asymmetric multi-collapse would provide some characteristics to the climactic pyroclastic flow in 7300 BP. Second, the bathymetric rise at the center of the caldera consists of high-amplitude surface and chaotic thick facies outwardly collapsed by intense normal

  6. Sedimentary sulfides in dune sands of Spiekeroog Island, southern North Sea: A biogeochemical study of sulfur isotope partitioning

    NASA Astrophysics Data System (ADS)

    Seibert, Stephan; Schubert, Florian; Schmiedinger, Iris; Böttcher, Michael E.; Massmann, Gudrun

    2017-04-01

    The formation of iron sulfides in sandy sediments and the associated development of stable isotope signatures is still mechanistically not understood. In dune sands under impact of both fresh and saline water several physico-chemical gradients may develop leading to distinctly different biogeochemical zones. In the present study, a 10 m long core from a dune base at the North Eastern part of Spiekeroog Island, southern North Sea, was investigated for the elemental and stable isotope composition. The pyrite (TRIS) content was quantitatively extracted via an acidic Cr(II) distillation procedure and the stable sulfur isotope composition was determined by means of C-irmMS. The pore waters display a downcore increase in salt contents and a mixing between fresh and salt water. The accumulation of metabolites at depth indicate an increasing superimposition of mixing by microbial decomposition of dissolved organic matter with only limited net sulfate reduction. This indicates an essential open system with respect to dissolved sulfate. The sands were found to be very low in TOC, TIC, and TRIS and dominated by quartz minerals. Under the assumption that North Sea water sulfate was the only substantial sulfate source (d34S = + 21per mil), the sedimentary sulfides indicate an overall sulfur isotope discrimination upon microbial sulfate reduction between 39 and 52 per mil, which is within the range of results from other fully marine sands from the Spiekeroog area and laboratory studies with pure cultures of sulfate-reducing bacteria under low cellular sulfate reduction rates. Further investigations are on the way to understand the processes leading to the iron sulfide formation in these organic-poor substrates.

  7. UK‧37 temperature estimates from Eemian marine sediments in the southern coast of Hainan Island, tropical China

    NASA Astrophysics Data System (ADS)

    Wang, Mengyuan; Zheng, Zhuo; Huang, Kangyou; Zong, Yongqiang; Liu, Zhonghui; Peng, Zhuolun; Shi, Suhua

    2016-09-01

    This study concerns high-resolution sea surface temperature (SST) changes for the Eemian interglacial period reconstructed from the southern coast of Hainan Island, China. The lower marine unit in the sediment core is composed of monotonous mud (31 m thick), dated to be from the Eemian interglacial period or lower part of marine isotope stage 5 (MIS 5), determined by optically stimulated luminescence (OSL). The high sedimentation rate and the richness of organic matter and marine fossils provide good opportunity for the study of palaeo-environments in the northern margin of the South China Sea (SCS). Sediment grain-size, foraminifer, sediment color index and long-chain alkenone were used to reveal the near-shore sedimentary environments and temperature at millennial-scale. Specifically, a high-resolution UK‧37-SST record was reconstructed for the Eemian interglacial period. The new evidence in northwestern margin of SCS shows that the maximum value of SST during the Eemian interglacial is approximately 29 °C and the lowest is 26.5 °C. The trend of decreasing SST from 29 °C throughout the marine sequence is consistent with the variations in sediment grain size, reflecting the cooling trend of SST and sea-level lowering tendency during the last interglacial period. This new Eemian SST result agrees with other records in the region of SCS, showing a coherent descending trend, but spatial heterogeneity exists in timing and amplitude. The insolation changes might be the main force for initiating the SST evolution during the penultimate interglacial period.

  8. The Last Termination in the South Indian Ocean: A unique terrestrial record from Kerguelen Islands (49°S) situated within the Southern Hemisphere westerly belt

    NASA Astrophysics Data System (ADS)

    Van der Putten, Nathalie; Verbruggen, Cyriel; Björck, Svante; Michel, Elisabeth; Disnar, Jean-Robert; Chapron, Emmanuel; Moine, Bertrand N.; de Beaulieu, Jacques-Louis

    2015-08-01

    The awareness of the significance of the Southern Ocean in the Earth's climate system has become increasingly obvious. The deglacial atmospheric CO2 rise during warming periods in Antarctica has been attributed to CO2 ventilation from the deep ocean caused by enhanced upwelling around the Antarctic Divergence. It has been hypothesized that, more intense Southern Hemisphere westerly winds aligned with the Antarctic Circumpolar Current due to a southward shift of the wind belt from its Last Glacial Maximum equator-ward position, are the main drivers. Reconstructions of past changes in atmospheric circulation in the Southern Hemisphere are still scarce and the overall picture is patchy with sometimes contradictory results. For obvious reasons, most terrestrial records originate from southern South America and New Zealand. Here we present a terrestrial record from the Indian sector of the Southern Ocean, from Kerguelen Islands located at 49°S. A peat record is investigated using a multi-proxy approach (pollen and plant macrofossils, magnetic susceptibility, XRF analyses, biogenic silica content, Rock-Eval6 analysis and humification degree). Peat accumulation starts at about 16,000 cal yr BP with relatively warm and dry conditions. The most prominent change in our proxy data occurs at 13,600 cal yr BP, when peat ponds were established on the peat surface, resulting in lacustrine-type deposits, as a result of very high humidity, and with proxies implying very windy conditions. Within chronological uncertainties, this onset coincides with the onset of the so-called Oceanic Cold Reversal, based on the deuterium excess data in the EPICA Dome C ice core record. Kerguelen Islands are located in the moisture source area of Dome C and a change in atmospheric circulation at that time could explain both records. Around 12,900 cal yr BP, at the end of the Antarctic Cold Reversal, pond/lake sediments give way to more peaty deposits, with proxies suggesting slightly drier, less

  9. Andes Mountains, Chile

    NASA Image and Video Library

    1994-09-30

    STS068-260-078 (30 September-11 October 1994) --- The ice visible along the bottom of this view is the north end of the larger (southern) of two great remaining ice field of the Andes Mountains in Chile. The longest glacier visible here flows down into the Calen Fjord (an arm of the Pacific Ocean known as Canal Baker) where numerous calved icebergs can be seen floating. The other three glaciers end in glacier-cut valleys with small lakes - the bigger lake has numerous icebergs as well. the river snaking through the mountains to the fjord drains water from the great Lake O'Higgins, which lies out of the picture to the right. Glacial mud can be seen emptying into the fjord and discoloring the water with its milky color.

  10. Feline immunodeficiency virus and feline leukemia virus infection in free-ranging guignas (Leopardus guigna) and sympatric domestic cats in human perturbed landscapes on Chiloé Island, Chile.

    PubMed

    Mora, Mónica; Napolitano, Constanza; Ortega, René; Poulin, Elie; Pizarro-Lucero, José

    2015-01-01

    Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are two of the most common viruses affecting domestic cats (Felis catus). During the last two decades, reports show that both viruses also infect or affect other species of the family Felidae. Human landscape perturbation is one of the main causes of emerging diseases in wild animals, facilitating contact and transmission of pathogens between domestic and wild animals. We investigated FIV and FeLV infection in free-ranging guignas (Leopardus guigna) and sympatric domestic cats in human perturbed landscapes on Chiloé Island, Chile. Samples from 78 domestic cats and 15 guignas were collected from 2008 to 2010 and analyzed by PCR amplification and sequencing. Two guignas and two domestic cats were positive for FIV; three guignas and 26 domestic cats were positive for FeLV. The high percentage of nucleotide identity of FIV and FeLV sequences from both species suggests possible interspecies transmission of viruses, facilitated by increased contact probability through human invasion into natural habitats, fragmentation of guigna habitat, and poultry attacks by guignas. This study enhances our knowledge on the transmission of pathogens from domestic to wild animals in the global scenario of human landscape perturbation and emerging diseases.

  11. Iodine-129, iodine-127 and caesium-137 in the environment: soils from Germany and Chile.

    PubMed

    Daraoui, A; Michel, R; Gorny, M; Jakob, D; Sachse, R; Synal, H-A; Alfimov, V

    2012-10-01

    Soil profiles from Bavaria in southern Germany and from Chile were analysed for (129)I by accelerator mass spectrometry (AMS), for (127)I by inductively coupled plasma mass spectrometry (ICP-MS), and for (137)Cs by gamma-spectrometry. The mean deposition density of (137)Cs in soils from Bavaria was (41×1.5(±1)) kBq m(-2) (geometric mean and geometric standard deviation), originating mostly from the Chernobyl fall-out. The deposition density of (129)I in these soils was (109×1.5(±1)) mBq m(-2). The dominant sources of (129)I in Bavaria are, however, the reprocessing plants La Hague and Sellafield and not the Chernobyl fall-out. The (129)I/(127)I isotopic ratios of the Bavarian soils were between 10(-7) and 10(-10), i.e. 10(2)-10(5) times higher than the ratios observed for the samples from Chile. The (129)I integral deposition densities in Chile, Easter Island and Antarctica were between 0.3 mBq m(-2) and 2 mBq m(-2). In these soils, the observed (129)I/(127)I ratios were about 10(-12). The soils from Chile allow the determination of the (129)I fall-out from the atmospheric nuclear weapons explosions undisturbed from contaminations due to releases from reprocessing plants. An upper limit of the integral (129)I deposition density of the atmospheric nuclear weapons explosions on the Southern Hemisphere (27°S) is about 1 mBq m(-2). Finally, the dependence of the migration behaviour of (137)Cs, (127)I and of (129)I on the soil properties is discussed. It turns out that there is a distinctly different behaviour of (127)I, (129)I, and (137)Cs in the soils exhibiting different sorption mechanisms for old and recent iodine as well as for (137)Cs.

  12. Enneophyllus ecarina, a new species of scaphopod shell dwelling hermit crab (Crustacea: Decapoda: Anomura: Paguridae) from deep-sea off the Ryukyu Islands, southern Japan.

    PubMed

    Komai, Tomoyuki

    2017-05-24

    A second species of the pagurid genus Enneophyllus McLaughlin, 1997, E. ecarina n. sp., is described and illustrated on the basis of two specimens collected from the upper bathyal depths off Amami-ohshima Island, Ryukyu Islands, southern Japan. The new species is immediately distinguished from the sole known congener, E. spinirostris McLaughlin, 1997, from the Banda Sea, Indonesia, by the non-operculiform right chela and fewer ventral spiniform setae of the ambulatory dactyli. The type species of Enneophillus, E. spinirostris, was represented only by the male holotype, and examination of the female paratype of this new species enables documentation of female characteristics in the generic diagnosis. Like E. spinirostris, the new species inhabits scaphopod shells.

  13. Geological Evidence That Resolves the Baja-BC Controversy: Detrital Zircons Indicate That Vancouver Island Was Adjacent to Southern California in the Late Cretaceous

    NASA Astrophysics Data System (ADS)

    Guest, B.; Matthews, W.; Coutts, D. S.; Bain, H.; Hubbard, S. M.

    2015-12-01

    The Baja-BC hypothesis is at the center of a great earth sciences controversy. It stems from paleomagnetic observations that require large-scale displacements of continental crust from low latitudes (Baja, California) to moderate latitudes (British Columbia). Many geologists dispute the scale of the displacements due to a lack of corroborating geological evidence. We provide a robust, geological dataset that confirms the paleomagnetic observations. Detrital zircons from Cretaceous to Paleocene sandstone of the Nanaimo Group, which crops out in western Vancouver Island and the Gulf Islands of southwest British Columbia, are analyzed. The data show a clear transition from local <300 Ma western Coast Plutonic Complex sources in the Campanian, to sources that include a significant component of >300 Ma grains in the Maastrichtian-Paleogene. An identical pattern is observed in detrital zircon datasets from southern California forearc basin deposits, and schists interpreted as the subducted remnants of forearc deposits. With a high-n dataset (n=3041) we are able to rule out possible >300 Ma source regions in Canada and the northern United States, and uniquely tie Nanaimo Group rocks to the Mojave-Sonora region of SW United States. This implies that at the end of the Cretaceous, Vancouver Island and western mainland BC were adjacent to southern California and northwestern Mexico, requiring 1900 km of displacement during the latest Cretaceous and Paleocene, consistent with paleomagnetic results. An implication of this result is that the western Coast Batholith of southwest BC was positioned between the northern Peninsular Ranges and southern Sierra Nevada batholiths in the late Cretaceous, and likely represents a displaced segment of a once continuous Cordilleran arc batholith. These results have broad implications for our understanding of episodic arc magmatism in the Cordillera, the tectonic evolution of western North America, Laramide orogenesis, the development and

  14. Current Discussions Between ESO and Chile

    NASA Astrophysics Data System (ADS)

    1995-04-01

    [Joint Press Release by the Government of the Republic of Chile and the European Southern Observatory. The text is issued simultaneously in Santiago de Chile (in Spanish) and at the ESO Headquarters in Garching (in English).] Today, Tuesday, 18 April 1995, at the ESO Headquarters in Garching (Germany), Mr. Roberto Cifuentes, Plenipotentiary Ambassador representing the Government of the Republic of Chile, and the Director General of the European Southern Observatory, Professor Riccardo Giacconi, have signed a Supplementary, Interpretative and Amending Agreement to the Convention of 6 November 1963 which governs the relations between Chile and this International Organisation. This Agreement which in practice signifies a widening and strengthening of the cooperative relations between the Organisation and the Chilean scientific community will hereafter be submitted for ratification by the National Congress of the Republic of Chile (the Parliament) and by the ESO Council. According to the Agreement signed today, Chilean astronomers will have privileged access within up to 10 percent observing time on all present and future ESO telescopes in Chile. Moreover, ESO accepts to incorporate into its labour regulations for Chilean personnel concepts like freedom of association and collective bargaining. This signing of the Supplementary, Interpretative and Amending Agreement to the original Convention of 1963 follows after months of constructive dialogue between the parties. It constitutes an important step towards a solution of some of the pending points on the current agenda for discussions between the Government of Chile and ESO. Among the issues still pending, ESO has informed the Government of Chile that respect for its immunities by the Chilean State is of vital importance for the continuation of the construction of the world's largest telescope at Paranal, as well as the continued presence of the Organisation in Chile. The Chilean Government, on its side, and concerning

  15. A Sarcocystid misidentified as Hepatozoon didelphydis: molecular data from a parasitic infection in the blood of the Southern mouse opossum (Thylamys elegans) from Chile.

    PubMed

    Merino, Santiago; Vásquez, Rodrigo A; Martínez, Javier; Celis-Diez, Juan L; Martínez-de la Puente, Josué; Marín-Vial, Paula; Sánchez-Monsalvez, Inocencia; Peirce, Michael A

    2008-01-01

    The blood of 21 adult South American mouse opossums (Thylamys elegans) captured from April through August of 2005 in central Chile was examined for parasites. Light microscopic analysis of blood smears initially suggested that a highly pleomorphic Hepatozoon species typical of American opossums was infecting erythrocytes. Unexpectedly, amplification by PCR and sequencing of a DNA fragment of the small subunit rDNA combined with phylogenetic analyses indicated that the parasite is not a member of the suborder Adeleorina, which includes the Haemogregarina and Hepatozoon species, but that it is a clearly distinct member of the suborder Eimeriorina, which includes the cyst-forming family Sarcocystidae. Therefore, a reclassification of this unusual intraerythrocytic apicomplexan will require additional life cycle, microscopic, and molecular analyses.

  16. The Loma Seca tuff and the Calabozos caldera: a major ash-flow and caldera complex in the southern Andes of central Chile.

    USGS Publications Warehouse

    Hildreth, W.; Grunder, A.L.; Drake, Robert E.

    1984-01-01

    A composite ring-structure caldera of Late Pleistocene age, 26 X 14km in size, has been discovered and mapped near the Andean crest in central Chile (35o 30'S). Rhyolitic to dacitic zoned ashflow sheets, each representing 150-300 km3 of magma, were erupted 0.8, 0.3 and 0.15 m.y. ago; the youngest of the associated collapses was closely followed by resurgent doming of the caldera floor and the development of a longitudinal graben. Post-caldera eruption of dacite and andesite have persisted into Holocene time and active hot springs are abundant along caldera-marginal and resurgent fault systems, suggesting a significant geothermal energy resource. The ash-flow magmatism has been no less important in this segment of the glaciated S Andes than in the arid central Andes and may well be accounted for by the existence of thicker crust in both regions.- L.H.

  17. CBPR-Informed Recruitment and Retention Adaptations in a Randomized Study of Pap Testing Among Pacific Islanders in Southern California

    PubMed Central

    Tanjasiri, Sora Park; Weiss, Jie W.; Santos, Lola; Flores, Peter; Flores, Preciosa; DeGuzman Lacsamana, Jasmine; Paige, Ciara; Mouttapa, Michele; Quitugua, Lourdes; Taito, Peniamina; May, Vanessa Tui’one; Tupua, Marina; Vaikona, Elenoa; Vaivao, Dorothy; Vunileva, Isileli

    2016-01-01

    Background Pacific Islanders (PIs) experience high cervical cancer rates in the United States. Stage of diagnosis is also later for PIs than non-Hispanic Whites. The Pap test is severely underutilized among PIs: only 71% of Asian American and Pacific Islander women age 25 years or older received a Pap test within the last 3 years (U.S. average, 82%). Community-based participatory research (CBPR) is increasingly seen as an essential approach in designing and conducting culturally relevant and appropriate studies that reduce cancer incidence and other health disparities among minority and other medically underserved populations. Purpose The purpose of this article is to describe the lessons learned thus far regarding the identification, recruitment, and retention of PI community organizations and members into a CBPR-informed, randomized, community trial promoting Pap testing. Methods This 5-year study used CBPR to develop and test the efficacy of a social support intervention for Chamorro, Samoan, and Tongan women to increase Pap testing in southern California. Eligible women were between the ages of 21 and 65, and married or in a long-term relationship with a man for at least 5 years. Women and their husbands or significant others received a 2-hour, culturally tailored workshop that include a group activity, information on Pap testing, a video, and corresponding materials. Comparison participants received a brochure about Pap testing. Three waves of data are collected from all participants: pretest (before workshop or brochure), posttest 1 (immediately after workshop or brochure), and posttest 2 (6 months follow-up). Results Of the 76 organizations approached to participate in the study, 67 (88.2%) eventually agreed to participate. Thus far, 473 women and 419 men completed the study pretest, post-test, education, and 6-month follow-up. Only 242 women and 204 men of the eligible participants have completed the follow-up survey (63.5% of women and 60.5% of men

  18. Delineation and Prediction Uncertainty of Areas Contributing Recharge to Selected Well Fields in Wetland and Coastal Settings, Southern Rhode Island

    USGS Publications Warehouse

    Friesz, Paul J.

    2010-01-01

    Areas contributing recharge to four well fields in two study sites in southern Rhode Island were delineated on the basis of steady-state groundwater-flow models representing average hydrologic conditions. The wells are screened in sand and gravel deposits in wetland and coastal settings. The groundwater-flow models were calibrated by inverse modeling using nonlinear regression. Summary statistics from nonlinear regression were used to evaluate the uncertainty associated with the predicted areas contributing recharge to the well fields. In South Kingstown, two United Water Rhode Island well fields are in Mink Brook watershed and near Worden Pond and extensive wetlands. Wetland deposits of peat near the well fields generally range in thickness from 5 to 8 feet. Analysis of water-level drawdowns in a piezometer screened beneath the peat during a 20-day pumping period indicated vertical leakage and a vertical hydraulic conductivity for the peat of roughly 0.01 ft/d. The simulated area contributing recharge for average withdrawals of 2,138 gallons per minute during 2003-07 extended to groundwater divides in mostly till and morainal deposits, and it encompassed 2.30 square miles. Most of a sand and gravel mining operation between the well fields was in the simulated contributing area. For the maximum pumping capacity (5,100 gallons per minute), the simulated area contributing recharge expanded to 5.54 square miles. The well fields intercepted most of the precipitation recharge in Mink Brook watershed and in an adjacent small watershed, and simulated streams ceased to flow. The simulated contributing area to the well fields included an area beneath Worden Pond and a remote, isolated area in upland till on the opposite side of Worden Pond from the well fields. About 12 percent of the pumped water was derived from Worden Pond. In Charlestown, the Central Beach Fire District and the East Beach Water Association well fields are on a small (0.85 square mile) peninsula in a

  19. Early-middle Eocene chronology of the Southern Ocean: magnetostratigraphic data from the South Island of New Zealand

    NASA Astrophysics Data System (ADS)

    Dallanave, E.; Bachtadse, V.; Agnini, C.; Muttoni, G.; Hollis, C. J.; Morgans, H. E.; Crampton, J. S.

    2012-12-01

    During the Paleogene the Earth experienced a pronounced warming trend culminating with the early Eocene climatic optimum (EECO, ~52-50 Ma), which was followed by a long-term cooling trend over the middle-late Eocene. This long-term climate evolution was punctuated by several transient (~10^3-5 yr) hyperthermal events (e.g. Paleocene Eocene thermal maximum). Even though great advances have been made in the last few years in understanding the paleoclimate history of the southwestern Pacific Ocean and the implications on the sedimentation patterns, a precise correlation between sites and global events is still missing. This is mainly because of the poor preservation of calcareous nannofossils, diachronous ranges of index species, and a lack of a good magnetic polarity reversals record. We present preliminary early-middle Eocene magnetostratigraphy from the Mid Waipara and the Mead Stream marine sections, cropping out in the South Island of New Zealand. These sections provide the best-known record of oceanic changes in the southern Pacific high-latitude (50-60°S) for this time period. Magnetostratigraphic data, integrated with new and published biostratigraphy, indicates that the sampled ~45 m of the Mid Waipara section straddles polarity Chrons from C23n to C21n (~51.5-47 Ma), with an average sediment accumulation rate of ~9 m/Myr, calculated by means of correlation with the GPTS2004 time scale. This robust chronological framework allow to constrain in time the paleotemperature dataset of Hollis et al. (EPSL 349-350, pp. 53-56, 2012), confirming that the Ashley Mudstone formation of Mid Waipara includes at least the upper part of the EECO and the early-middle Eocene transition. The sampled ~320 m of the Mead Stream section, which comprises the three upper member of the Amuri Limestone (Lower Marl, Upper Limestone and Upper Marl), encompass polarity Chrons from C24r to C18r (~55-40 Ma), with an average sedimentation rate of ~17 m/Myr. We confirm evidence from carbon

  20. Aerosol characterization and radiative properties over Kavaratti, a remote island in southern Arabian Sea from the period of observations.

    PubMed

    Patel, Piyushkumar N; Dumka, U C; Babu, K N; Mathur, A K

    2017-12-01

    Long-term measurements of spectral aerosol optical depth (AOD) using sun/sky radiometer for a period of five years (2009-2014) from the remote island location at Kavaratti (KVT; 10.56°N, 72.64°E) in the southern Arabian sea have been analysed. Climatologically, AODs decrease from October to reach maximum of ~0.6 (at 500nm) in March, followed by a sudden fall towards May. Significant modulations of intra-seasonal timescales over this general pattern are noticed due to the changes in the relative strength of distinctively different sources. The corresponding changes in aerosol inversion parameters reveal the presence of coarse-mode aerosols during spring and fine-mode absorbing aerosols in autumn and winter months. An overall dominance of a mixed type of aerosols (~41%) with maximum in winter (~53%) was found via the AOD500 vs. Ångström exponent (α440-870) relationship, while biomass-burning aerosols or thick urban/industrial plumes contribute to ~19%. Spectral dependence of Ångström exponent and aerosol absorbing properties were used to identify the aerosol types and its modification processes. Based on air mass back trajectory analysis, we revealed that the advection of aerosols from Indian subcontinent and western regions plays a major role in modifying the optical properties of aerosols over the observational site. The shortwave aerosol direct radiative forcing estimated via SBDART model ranges from -11.00Wm(-2) to -7.38Wm(-2), -21.51Wm(-2) to -14.33Wm(-2) and 3.17Wm(-2) and 10.0Wm(-2) at top of atmosphere, surface and within the atmosphere, respectively. This atmospheric forcing translates into heating rate of 0.62-1.04Kday(-1). Furthermore, the vertical profiles of aerosols and heating rate exhibit significant increase in lower (during winter and autumn) and mid troposphere (during spring). This may cause serious climate implications over Kavaratti with further consequences on cloud microphysics and monsoon rainfall. Copyright © 2017 Elsevier B.V. All

  1. Geology and ground-water conditions in southern Nassau and southeastern Queens Counties, Long Island, New York

    USGS Publications Warehouse

    Perlmutter, N.M.; Geraghty, J.J.

    1963-01-01

    Test drilling, electrical logging, and water sampling of 'outpost' and other wells have revealed the existence of a deep confined body of salt water in the Magothy(?) formation beneath southwestern Nassau and southeastern Queens Counties, Long Island, N.Y. In connection with a test-drilling program, cooperatively sponsored by the U.S. Geological Survey, the Nassau County Department of Public Works, and the New York State Water Resources Commission (formerly Water Power and Control Commission), 13 wells ranging in depth from about 130 to 800 feet were drilled during 1952 and 1953 and screened at various depths in the Magothy(?) formation and Jameco gravel. On the basis of the preliminary geologic, hydrologic, and chemical data from these wells, a detailed investigation of ground-water conditions from the water table to the bedrock was begun in a 200-square-mile area in southern Nassau and southeastern Queens Counties. The Inain purposes of the investigation were to delineate the bodies of fresh and salty ground water in the project area, to relate their occurrence and movement to geologic and hydrologic conditions, to estimate the rate of encroachment, if any, of the salty water, and to evaluate the effectiveness of the existing network of outpost wells as detectors of salt-water encroachment. About a million people in the report area, residing mainly in southern Nassau County, are completely dependent on ground water as a source of supply. Fortunately, precipitation averages about 44 inches per year, of which approximately half is estimated to percolate into the ground-water reservoir. The ground water is contained in and moves through eight differentiated geologic units composed of unconsolidated gravel, sand, and clay, of Late Cretaceous, Pleistocene, and Recent age, having a maximum total thickness of about 1,700 feet. The underlying metamorphic and igneous crystalline basement rocks are of Precambrian age and are not water bearing. The water-yielding units from

  2. Estimated water use and availability in the Pawcatuck Basin, southern Rhode Island and southeastern Connecticut, 1995-99

    USGS Publications Warehouse

    Wild, Emily C.; Nimiroski, Mark T.

    2004-01-01

    In 1988, the Pawcatuck Basin (302.4 square miles) in southern Rhode Island (245.3 square miles) and southeastern Connecticut (57.12 square miles) was defined as a sole-source aquifer for 14 towns in southern Rhode Island and 4 towns in southeastern Connecticut. To determine water use and availability, the six subbasins in the Pawcatuck Basin were delineated on the basis of the surface- and ground-water system drainage areas. From 1995 through 1999, five major water suppliers in the basin withdrew an average of 6.768 million gallons per day from the aquifers. The estimated water withdrawals from minor water suppliers during the study period were 0.099 million gallons per day. Self-supplied domestic, industrial, commercial, and agricultural withdrawals from the basin averaged 4.386 million gallons per day. Water use in the basin averaged 7.401 million gallons per day. The average return flow in the basin was 7.855 million gallons per day, which included effluent from permitted facilities and self-disposed water users. The PART program, a computerized hydrographseparation application, was used for five selected index streamgaging stations to determine water availability on the basis of the 75th, 50th, and 25th percentiles of the total base flow, the base flow minus the 7-day, 10-year flow criteria, and the base flow minus the Aquatic Base Flow criteria at the index stations. The differences in the surface- and ground-water system drainage areas in the summer were applied to the water availability calculated at the index stations and subbasins. The base-flow contributions from sand and gravel deposits at the index stations were computed for June, July, August, and September, and applied to the percentage of surficial deposits at each index station. The base-flow contributions were converted to a per unit area at the station for the till, and for the sand and gravel deposits, and applied to the subbasins. The statistics used to estimate the gross yield of base flow, as

  3. The Channel Islands Thrust Fault, Southern California: Structure at the Juncture Between the Western Transverse Ranges and the Continental Borderland

    NASA Astrophysics Data System (ADS)

    Fisher, M. A.; Langenheim, V. E.

    2004-12-01

    Potential-field data over the northern Channel Islands and Santa Barbara basin and seismic reflection data collected near these islands show the crustal structure near the tip of the Channel Island thrust fault. This fault dips north to underlie the Santa Barbara basin and is part of the regional fault system that separates the western Transverse Ranges from the California Continental Borderland. Our investigation focuses on Santa Cruz Island, where a local exposure of mainly Jurassic ophiolitic basement rocks includes the Willows Plutonic Complex. These mafic and ultramafic igneous rocks produce strong magnetic and gravity anomalies, showing that fragments of the Willows Plutonic Complex have been carried northwestward into or below the basin by sinistral translation of hanging-wall blocks in the thrust system. The potential-field anomalies indicate a cumulative left-lateral offset of about 20 km along what is probably the Santa Cruz Island fault. This fault is known from onshore trenching to be primarily a left-lateral strike-slip fault that was active during late Quaternary time. Seismic-reflection data show that where the Santa Cruz Island fault projects into the offshore a fault-bend fold deforms stratified rock in the Santa Barbara basin. Slip along this fault is partitioned into strike-slip and southwest-vergent reverse components. The Santa Cruz Island fault formed where structures of the California Borderland terminate to the northwest against the rocks that make up the northern Channel Islands. Structures developed at this termination may be similar to ones that formed where the Newport-Inglewood and the San Pedro Basin faults end to the northwest against the Santa Monica Mountains. These terminating faults pose a considerable earthquake hazard, and findings from the area of Santa Cruz Island may help elucidate this hazard.

  4. A sea surface temperature reconstruction for the southern Indian Ocean trade wind belt from corals in Rodrigues Island (19° S, 63° E)

    NASA Astrophysics Data System (ADS)

    Zinke, Jens; Reuning, Lars; Pfeiffer, Miriam; Wassenburg, Jasper A.; Hardman, Emily; Jhangeer-Khan, Reshad; Davies, Gareth R.; Ng, Curtise K. C.; Kroon, Dick

    2016-10-01

    The western Indian Ocean has been warming rapidly over recent decades, causing a greater number of extreme climatic events. It is therefore of paramount importance to improve our understanding of links between Indian Ocean sea surface temperature (SST) variability, climate change and sustainability of tropical coral reef ecosystems. Here we present monthly resolved coral Sr / Ca records from two different locations from Rodrigues Island (63° E, 19° S) in the south-central Indian Ocean trade wind belt. We reconstruct SST based on a linear relationship with the Sr / Ca proxy with records starting from 1781 and 1945, respectively. We assess relationships between the observed long-term SST and climate fluctuations related to the El Niño-Southern Oscillation (ENSO), the Subtropical Indian Ocean Dipole Mode (SIOD) and the Pacific Decadal Oscillation (PDO) between 1945 and 2006, respectively. The reproducibility of the Sr / Ca records is assessed as are the potential impacts of diagenesis and corallite orientation on Sr / Ca-SST reconstructions. We calibrate individual robust Sr / Ca records with in situ SST and various gridded SST products. The results show that the SST record from Cabri provides the first Indian Ocean coral proxy time series that records the SST signature of the PDO in the south-central Indian Ocean since 1945. We suggest that additional records from Rodrigues Island can provide excellent records of SST variations in the southern Indian Ocean trade wind belt to unravel teleconnections with the SIOD/ENSO/PDO on longer timescales.

  5. Long-term decrease of atmospheric test {sup 137}Cs in the soil-prairie plant-milk pathway in southern Chile

    SciTech Connect

    Schuller, P. Ellies, A.; Handl, J.

    1998-07-01

    The time dependency of nuclear test {sup 137}Cs in soil, prairie plants, and milk was observed on pastures of seven dairy farms in the 10th Region, Chile, from 1982 to 1997, without any appreciable deposition of radioactive fallout after 1983. Whereas the {sup 137}Cs concentration in the soil decreased at a rate close to that of the radionuclide`s physical decay during the whole observation period, the rate of decrease of the {sup 137}Cs concentration in the prairie plants and in the milk, having been very rapid between 1982--1990, became slower between 1991--1997. The effective half-lives of the concentration in plants were found to be 5.6 y and 12 y during the first and second observation periods, respectively. Similar half-lives of 5.5 y and 13 y were found for the concentration decline in milk during each period. These data clearly demonstrate a reduction in the long-term decrease of the {sup 137}Cs plant uptake, and consequently in the decrease of the {sup 137}Cs concentration in milk, resulting from a decline of {sup 137}Cs availability for prairie plants in the Hapludand soils over the whole 15-y observation period.

  6. Green turtles (Chelonia mydas) foraging at Arvoredo Island in Southern Brazil: Genetic characterization and mixed stock analysis through mtDNA control region haplotypes.

    PubMed

    Proietti, Maíra Carneiro; Lara-Ruiz, Paula; Reisser, Júlia Wiener; da Silva Pinto, Luciano; Dellagostin, Odir Antonio; Marins, Luis Fernando

    2009-07-01

    We analyzed mtDNA control region sequences of green turtles (Chelonia mydas) from Arvoredo Island, a foraging ground in southern Brazil, and identified eight haplotypes. Of these, CM-A8 (64%) and CM-A5 (22%) were dominant, the remainder presenting low frequencies (< 5%). Haplotype (h) and nucleotide (π) diversities were 0.5570 ± 0.0697 and 0.0021 ± 0.0016, respectively. Exact tests of differentiation and AMOVA Φ(ST) pairwise values between the study area and eight other Atlantic foraging grounds revealed significant differences in most areas, except Ubatuba and Rocas/Noronha, in Brazil (p > 0.05). Mixed Stock Analysis, incorporating eleven Atlantic and one Mediterranean rookery as possible sources of individuals, indicated Ascension and Aves islands as the main contributing stocks to the Arvoredo aggregation (68.01% and 22.96%, respectively). These results demonstrate the extensive relationships between Arvoredo Island and other Atlantic foraging and breeding areas. Such an understanding provides a framework for establishing adequate management and conservation strategies for this endangered species.

  7. Seismic hazard along the southern boundary of the Gônave microplate: block modelling of GPS velocities from Jamaica and nearby islands, northern Caribbean

    NASA Astrophysics Data System (ADS)

    Benford, B.; DeMets, C.; Tikoff, B.; Williams, P.; Brown, L.; Wiggins-Grandison, M.

    2012-07-01

    We use block modelling of GPS site velocities from Jamaica and nearby islands, including Hispaniola, to test alternative plate boundary geometries for deformation in Jamaica and estimate slip rates along the island's major fault zones. Relative to the Caribbean Plate, GPS sites in northern Jamaica move 6.0 ± 0.5 mm yr-1 to the WSW, constituting a lower bound on the motion of the Gônave microplate across its southern boundary in Jamaica. Obliquely convergent motion of all 30 GPS sites on and near Jamaica relative to the island's ˜E-W-trending strike-slip faults may be partitioned into 2.6 ± 0.6 mm yr-1 of ˜N-S shortening across submarine faults south of Jamaica and 5-6 mm yr-1 of E-W motion. Guided by geological and seismic information about the strikes and locations of faults in Jamaica, inverse block modelling of the regional GPS velocities rejects plate boundary configurations that presume either a narrow plate boundary in Jamaica or deformation concentrated across a restraining bend defined by the topographically high Blue Mountains of eastern Jamaica. The best-fitting models instead place most deformation on faults in central Jamaica. The 4-5 mm yr-1 slip rate we estimate for the Plantain Garden fault and Blue Mountain restraining bend of southeastern Jamaica implies significant seismic hazard for the nearby capital of Kingston.

  8. Investigating the March 28th 1875 and the September 20th 1920 earthquakes/tsunamis of the Southern Vanuatu arc, offshore Loyalty Islands, New Caledonia

    NASA Astrophysics Data System (ADS)

    Ioualalen, Mansour; Pelletier, Bernard; Solis Gordillo, Gabriela

    2017-07-01

    New Caledonia's Loyalty Islands are located in the southwest region of the Pacific ocean in the highly seismogenic southern Vanuatu subduction zone and therefore may be subject to devastating local tsunamis. Over the past 150 years, two large tsunamis were triggered by major earthquakes on March 28th 1875 and September 20th 1920. In this study, we use historical observations of these tsunamis (mostly in the form of testimonials), earthquake scenarios, and tsunami modeling to derive the magnitudes of these earthquakes, as well as tsunami runup and inundation maps. Assuming that these earthquakes were located on the interplate megathrust zone, the 1875 earthquake's magnitude was Mw8.1-8.2 and the 1920 event's magnitude was Mw7.5-7.8. The tsunami damage inflicted on the Lifou and Maré islands was approximately proportional to these magnitudes, with Maré being less impacted due to favorable wave directivity. Damage at Ouvéa island may have varied irregularly with the magnitude due to the effects of resonance. This study demonstrates that the quantitative characteristics of historical tsunamigenic earthquakes may be derived from qualitative estimates of tsunami runup.

  9. Green turtles (Chelonia mydas) foraging at Arvoredo Island in Southern Brazil: Genetic characterization and mixed stock analysis through mtDNA control region haplotypes

    PubMed Central

    2009-01-01

    We analyzed mtDNA control region sequences of green turtles (Chelonia mydas) from Arvoredo Island, a foraging ground in southern Brazil, and identified eight haplotypes. Of these, CM-A8 (64%) and CM-A5 (22%) were dominant, the remainder presenting low frequencies (< 5%). Haplotype (h) and nucleotide (π) diversities were 0.5570 ± 0.0697 and 0.0021 ± 0.0016, respectively. Exact tests of differentiation and AMOVA ΦST pairwise values between the study area and eight other Atlantic foraging grounds revealed significant differences in most areas, except Ubatuba and Rocas/Noronha, in Brazil (p > 0.05). Mixed Stock Analysis, incorporating eleven Atlantic and one Mediterranean rookery as possible sources of individuals, indicated Ascension and Aves islands as the main contributing stocks to the Arvoredo aggregation (68.01% and 22.96%, respectively). These results demonstrate the extensive relationships between Arvoredo Island and other Atlantic foraging and breeding areas. Such an understanding provides a framework for establishing adequate management and conservation strategies for this endangered species. PMID:21637527

  10. Use of traps to capture black and gold howlers (Alouatta caraya) on the Islands of the upper Paraná River, Southern Brazil.

    PubMed

    Aguiar, Lucas M; Ludwig, Gabriela; Svoboda, Walfrido K; Teixeira, Gustavo M; Hilst, Carmen L S; Shiozawa, Marcos M; Malanski, Luciano S; Mello, Angel M; Navarro, Italmar T; Passos, Fernando C

    2007-02-01

    Howlers (genus Alouatta) are widely captured with the use of anesthetic projectiles; however, no capture protocol involving the use of traps has been described to date. In the present study we describe the first efficient capture program for black and gold howlers (Alouatta caraya) using traps, which was implemented on the islands of the upper Paraná River in southern Brazil. We constructed two trap models with either manual or automatic activation (trap A with two entrances and guillotine-type doors; trap B with one entrance and a guillotine-type door). The traps were suspended in the canopy by means of vertical climbing techniques, and were baited regularly and abundantly with bananas and mangoes. We captured 70 howlers (86% using manual activation and 14% using automatic activation) on four different islands. We restrained 41 of these animals and measured their body mass, which averaged 5.30 kg+/-1.79. Given our results, we suggest that the system described in the present study represents an alternative capture program for howlers in areas that have low food diversity and no other mammal species that will compete for the bait, as has been observed in riparian environments, islands, and forest fragments.

  11. Vegetation and climate dynamics of southern Chile during the past 50,000 years: results of ODP Site 1233 pollen analysis

    NASA Astrophysics Data System (ADS)

    Heusser, Linda; Heusser, Cal; Pisias, Nicklas

    2006-03-01

    High-resolution pollen data from ODP Site 1233 (41°0.005S, 74°26.992W, 838 m water depth) provide a continuous, chronostratigraphically controlled ˜50,000-yr record of regional changes in vegetation from temperate South America. Deposited ˜38 km west of the transition from northern, summer-green, lowland forest to southern evergreen rain forest, the 135 m core documents the comparatively brief Holocene development of thermophilous vegetation (Lowland Deciduous Beech Forest and Valdivian Evergreen Forest), and the expansion of glacial, subantarctic vegetation (North Patagonian Evergreen Forest-Subantarctic Parkland) during Marine Isotope State (MIS) 2 and 3. Systematic variability in these terrestrial climate proxies that reflect latitudinal movement of the southern westerlies is mirrored in co-eval ocean conditions inferred from radiolaria census data and in Antarctic climate records.

  12. April 16, 2015 Crete Island Earthquake (Mw=5.9) Series and its Seismotectonic Significance, Southern Aegean Sea

    NASA Astrophysics Data System (ADS)

    Yalçın, Hilal; Kürçer, Akın; Gülen, Levent

    2016-04-01

    The active deformation of the southern Aegean Sea is a result of the northward motion of the African and Arabian Plates with respect to the Eurasian Plate in the Eastern Mediterranean Region. The Hellenic subduction zone plays a key role in the active tectonics of the region. On 16 April, 2015, a moderate earthquake occurred on the eastern part of Hellenic arc (south of Crete island), with a moment magnitude of Mw=5.9. A series of aftershocks were occurred within four months following the mainshock, which have magnitudes varying from Mw = 3.4 to 5.4. Source parameters of the 16 April 2015 earthquake have been modeled in order to reveal the regional stress tensor and the tectonic style of the region. In this study, the source parameters of the main shock and 36 aftershocks that have magnitudes M≥3.4 have been determined and modeled by seismic moment tensor waveform inversion method developed by Sokos and Zahradnik (2006) algorithm using the near-field and regional waveforms. The depth of earthquakes are varied from 2 to 61 km. Stress tensor can describe reliably principle stress axes (σ1, σ2, σ3), their relative size and stress field variations. Stress tensor inversions have been carried out using the Micheal method (1984, 1987). In this study, 16 April 2015 Crete Earthquake mainshock (Mw=5.9), a total of 36 earthquake moment tensor solutions that belong to the Crete earthquake sequence and 24 earthquake moment tensor solutions of previous main shocks in the region have been compiled and used in the stress inversion calculation. Orientations of σ1, σ2 and σ3 were computed and the principal directions are projected onto a lower hemisphere Wulff net. The best fit was attained for Phi = 0.38+/-0.13609 and indicated that the stress regime revealed strike-slip faulting with reverse component and for the azimuth and plunge pair of (-161.6°, 21.7°) for σ1, (-11.1°, 65.4°) for σ2 and (103.8°, 10.9°) for σ3. At the final step of the study, Gutenberg and

  13. Seismology in Chile

    USGS Publications Warehouse

    Kausel, E.

    1983-01-01

    The Department of Geology and Geophysics, which is under the faculties of Mathematics and Physical Sciences of the University of Chile, is the organization that is responsible for the Seismological Service of Chile and for installing,operating, and maintaining the seismological stations as well as all the strong-motion stations in Chile.

  14. Estimated water use and availability in the South Coastal Drainage Basin, southern Rhode Island, 1995-99

    USGS Publications Warehouse

    Wild, Emily C.; Nimiroski, Mark T.

    2005-01-01

    The South Coastal Drainage Basin includes approximately 59.14 square miles in southern Rhode Island. The basin was divided into three subbasins to assess the water use and availability: the Saugatucket, Point Judith Pond, and the Southwestern Coastal Drainage subbasins. Because there is limited information on the ground-water system in this basin, the water use and availability evaluations for these subbasins were derived from delineated surface-water drainage areas. An assessment was completed to estimate water withdrawals, use, and return flow over a 5-year study period from 1995 through 1999 in the basin. During the study period, one major water supplier in the basin withdrew an average of 0.389 million gallons per day from the sand and gravel deposits. Most of the potable water is imported (about 2.152 million gallons per day) from the adjacent Pawcatuck Basin to the northwest. The estimated water withdrawals from the minor water suppliers, which are all in Charlestown, during the study period were 0.064 million gallons per day. The self-supplied domestic, industrial, commercial, and agricultural withdrawals from the basin were 0.574 million gallons per day. Water use in the basin was 2.874 million gallons per day. The average return flow in the basin was 1.190 million gallons per day, which was entirely from self-disposed water users. In this basin, wastewater from service collection areas was exported (about 1.139 million gallons per day) to the Narragansett Bay Drainage Basin for treatment and discharge. During times of little to no recharge, in the form of precipitation, the surface- and ground-water system flows are from storage primarily in the stratified sand and gravel deposits, although there is flow moving through the till deposits at a slower rate. The ground water discharging to the streams, during times of little to no precipitation, is referred to as base flow. The PART program, a computerized hydrograph-separation application, was used at the

  15. Using Satellite Tracking and Isotopic Information to Characterize the Impact of South American Sea Lions on Salmonid Aquaculture in Southern Chile

    PubMed Central

    Sepúlveda, Maritza; Newsome, Seth D.; Pavez, Guido; Oliva, Doris; Costa, Daniel P.; Hückstädt, Luis A.

    2015-01-01

    Apex marine predators alter their foraging behavior in response to spatial and/or seasonal changes in natural prey distribution and abundance. However, few studies have identified the impacts of aquaculture that represents a spatially and temporally predictable and abundant resource on their foraging behavior. Using satellite telemetry and stable isotope analysis we examined the degree of spatial overlap between the South American sea lion (SASL) and salmon farms, and quantify the amount of native prey versus farmed salmonids in SASL diets. We instrumented eight SASL individuals with SRDL-GPS tags. Vibrissae, hair and skin samples were collected for δ13C and δ15N analyses from five of the tagged individuals and from four males captured in a haul-out located adjacent to salmon farms. Tracking results showed that almost all the foraging areas of SASL are within close proximity to salmon farms. The most important prey for the individuals analyzed was farmed salmonids, with an estimated median (±SD) contribution of 19.7 ± 13.5‰ and 15.3 ± 9.6‰ for hair and skin, respectively. Using vibrissae as a temporal record of diet for each individual, we observed a remarkable switch in diet composition in two SASL, from farmed salmonids to pelagic fishes, which coincided with the decrease of salmon production due to the infectious salmon anemia virus that affected salmon farms in Chile at the end of 2008. Our study demonstrates the usefulness of integrating stable isotope derived dietary data with movement patterns to characterize the impacts of a non-native prey on the foraging ecology of an apex marine predator, providing important applied implications in situations where interactions between aquaculture and wildlife are common. PMID:26309046

  16. Using Satellite Tracking and Isotopic Information to Characterize the Impact of South American Sea Lions on Salmonid Aquaculture in Southern Chile.

    PubMed

    Sepúlveda, Maritza; Newsome, Seth D; Pavez, Guido; Oliva, Doris; Costa, Daniel P; Hückstädt, Luis A

    2015-01-01

    Apex marine predators alter their foraging behavior in response to spatial and/or seasonal changes in natural prey distribution and abundance. However, few studies have identified the impacts of aquaculture that represents a spatially and temporally predictable and abundant resource on their foraging behavior. Using satellite telemetry and stable isotope analysis we examined the degree of spatial overlap between the South American sea lion (SASL) and salmon farms, and quantify the amount of native prey versus farmed salmonids in SASL diets. We instrumented eight SASL individuals with SRDL-GPS tags. Vibrissae, hair and skin samples were collected for δ13C and δ15N analyses from five of the tagged individuals and from four males captured in a haul-out located adjacent to salmon farms. Tracking results showed that almost all the foraging areas of SASL are within close proximity to salmon farms. The most important prey for the individuals analyzed was farmed salmonids, with an estimated median (±SD) contribution of 19.7 ± 13.5‰ and 15.3 ± 9.6‰ for hair and skin, respectively. Using vibrissae as a temporal record of diet for each individual, we observed a remarkable switch in diet composition in two SASL, from farmed salmonids to pelagic fishes, which coincided with the decrease of salmon production due to the infectious salmon anemia virus that affected salmon farms in Chile at the end of 2008. Our study demonstrates the usefulness of integrating stable isotope derived dietary data with movement patterns to characterize the impacts of a non-native prey on the foraging ecology of an apex marine predator, providing important applied implications in situations where interactions between aquaculture and wildlife are common.

  17. Late summer distribution and stoichiometry of dissolved N, Si and P in the Southern Ocean near Heard and McDonald Islands on the Kerguelen Plateau

    NASA Astrophysics Data System (ADS)

    Chase, Z.; Bowie, A. R.; Blain, S.; Holmes, T.; Rayner, M.; Sherrin, K.; Tonnard, M.; Trull, T. W.

    2016-12-01

    The Kerguelen plateau in the Southern Indian Ocean is a naturally iron-fertilised region surrounded by iron-limited, High Nutrient Low Chlorophyll waters. The Heard Earth Ocean Biosphere Interaction (HEOBI) project sampled waters south of the Polar Front in the vicinity of Heard and McDonald Islands (HIMI) in January and February 2016. Fe fertilised waters over the plateau generally exhibited high phytoplankton biomass and photosynthetic competency (as in previous studies and satellite observations), but interestingly, phytoplankton biomass was low near HIMI, though photosynthetic competency was high. In plateau waters away from HIMI, silicic acid (Si) concentrations were strongly depleted in surface waters, averaging 3 μM, while nitrate concentrations were close to 25 μM. Relative to the remnant winter water, this represents an average seasonal drawdown of 32 μM Si and only 8 μM nitrate. Though absolute drawdown was lower at an HNLC reference site south of Heard Island, the drawdown ratio was similarly high (∆Si: ∆N 4-5). The average N:P drawdown ratio was 12, typical for a diatom-dominated system (Weber and Deutsch 2010). N:P drawdown was positively correlated with Si drawdown, perhaps indicative of an impact of Fe on both seasonal Si drawdown and diatom N:P uptake (Price 2005). In the well-mixed, shallow waters (< 200 m) around HIMI nutrient concentrations were elevated, with no surface nutrient depletion. Nutrient concentrations near the islands were generally consistent with input from vertical mixing of the regional nutrient profile. However, N* values (N* = N - P*16) near the islands were anomalously low (-5 to -7) relative to the regional nutrient profile (N* 3). Subsurface minima in N* (as low as -6) were observed just below the pycnocline at several plateau stations. If negative N* values here are indicative of intense remineralisation of P-rich organic matter, and possible preferential remineralisation of P (Blain et al. 2015), these observations

  18. Submillennial palynology and palaeoecology of the last glaciation at Taiquemó (˜50,000 cal yr, MIS 2 4) in southern Chile

    NASA Astrophysics Data System (ADS)

    Heusser, C. J.; Heusser, L. E.

    2006-03-01

    Stratigraphic palynology of core HE94-2B from a mire at Taiquemó (42.17°S, 73.60°W) on Isla Grande de Chiloé is one of the most closely sampled, continuous Pleistocene records in southern South America. Chronology of the 655-cm core that extends from Marine Isotope Stage (MIS) 4 through the Lateglacial is controlled by 27 finite radiocarbon dates. Sampled at 1-cm intervals, the high temporal resolution (mean ˜85 yr cm -1) captures short-term palaeoecological changes and successional restabilization of plant communities. Preponderance of Gramineae (grass) with Nothofagus dombeyi type (southern beech) characterizing Subantarctic Parkland under a cold climate in MIS 4 was followed by a conspicuously milder interval that lasted for some ten millennia in MIS 3. Of greater frequency and diversity at this time were more thermophilic taxa associated with North Patagonian Evergreen Forest ( Podocarpus, Pilgerodendron type , Pseudopanax, Myrtaceae). Subsequently with increasing cold and hyperhumidity, N. dombeyi type-Gramineae assemblages that included Subantarctic Parkland indicator taxa ( Lepidothamnus, Astelia, Gaimardia) increased stepwise in MIS 2-3. Parkland maxima in MIS 2 during the Last Glacial Maximum (LGM) date to glacial advances between ˜17,800 and 33,400 cal yr BP. On deglaciation, Lateglacial North Patagonian Evergreen Forest was subject to short-term stadial and interstadial climatic fluctuations. The high-resolution Taiquemó pollen record details and supports previous conclusions of interhemispheric synchrony of climatic and glacial events.

  19. Case of correlation between Rn anomalies and seismic activity on a volcano (Vulcano Island, Southern Tyrrhenian Sea)

    SciTech Connect

    Del Pezzo, E.; Gasparini, P.; Mantovani, M.S.M.; Martini, M.; Capaldi, G.; Gomes, Y.T.; Pece, R.

    1981-09-01

    A factor of 10 increase in the Rn concentration in a shallow aquifer forefunning a shallow seismic swarm was observed at the island of Vulcano (Aeolian island arc). The peak of Rn anomaly preceded by about one month the seismic swarm, which had a cumulative magnitude of 2.1. The time lag between the two phenomena is much longer than expected, given the small energy released by the swarm. The observed phenomena may not have a direct cause-effect relationship, but they both can be a consequence of volcanic phenomena.

  20. In situ U-Pb age determination and Nd isotopic analysis of perovskites from kimberlites in southern Africa and Somerset Island, Canada

    NASA Astrophysics Data System (ADS)

    Wu, Fu-Yuan; Yang, Yue-Heng; Mitchell, Roger H.; Li, Qiu-Li; Yang, Jin-Hui; Zhang, Yan-Bin

    2010-03-01

    Determination of the emplacement ages and initial isotopic composition of kimberlite by conventional isotopic methods using bulk rock samples is unreliable as these rocks usually contain diverse clasts of crustal- and mantle-derived materials and can be subject to post-intrusion sub-aerial alteration. In this study, 8 samples from 5 kimberlites in southern Africa and twelve samples from 7 kimberlites from Somerset Island, Canada have been selected for in situ perovskite U-Pb isotopic age determination and Nd isotopic analysis by laser ablation using thin sections and mineral separates. These fresh perovskites occur as primary groundmass minerals with grain-sizes of 10-100 μm. They were formed during the early stage of magmatic crystallization, and record data for the least contaminated or contamination-free kimberlitic magma. U-Pb isotopic data indicate that the majority of the southern Africa kimberlites investigated were emplaced during the Cretaceous with ages of 88 ± 3 to 97 ± 6 Ma, although one sample yielded an Early Paleozoic age of 515 ± 6 Ma. Twelve samples from Somerset Island yielded ages ranging from 93 ± 4 Ma to 108 ± 5 Ma and are contemporaneous with other Cretaceous kimberlite magmatism in central Canada (103-94 Ma). Although whole-rock compositions of the kimberlites from southern Africa have a large range of ɛNd( t) values (- 0.5 to + 5.1), the analysed perovskites show a more limited range of + 1.2 to + 3.1. Perovskites from Somerset Island have ɛNd( t) values of - 0.2 to + 1.4. These values are lower than that of depleted asthenospheric mantle, suggesting that kimberlites might be derived from the lower mantle. This study shows that in situ U-Pb and Nd isotopic analysis of perovskite by laser ablation is both rapid and economic, and serves as a powerful tool for the determination of the emplacement age and potential source of kimberlite magmas.

  1. The Araucanian Indian in Chile. IWGIA Document 20.

    ERIC Educational Resources Information Center

    Berdichewsky, Bernardo

    One of the larger of the native peoples of South America, the Araucanians include different ethnic subgroups, some of which are now extinct. Once geographically spread extensively over the southern cone of South America, at present they are reduced to only two closely related groups: (1) the Mapuche of southern Chile, the largest one; and (2) the…

  2. Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the southern part of Chile.

    PubMed

    Zamorano, Ruben; Marín, Michelle; Cabrera, Fabiola; Figueroa, Diego; Contreras, Cristóbal; Barriga, Andrés; Lagos, Néstor; García, Carlos

    2013-01-01

    The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55-2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of

  3. Falkland Islands, UK

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Falkland Islands (52.0S, 58.5W) was taken with a dual camera mount. Compare this scene with STS048-109-043 to analyze the unique properties of each film type. Seldom seen cloud free, the Falkland Islands lie off the southern coast of Argentina. The cold Falklands Ocean Current keeps the islands chilly, ideal for sheep herding and fishing, the two main industries. Colonies of seals and penguins also thrive on the islands.

  4. Falkland Islands, UK

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Falkland Islands (52.0S, 58.5W) was taken with a dual camera mount. Compare this scene with STS048-109-043 to analyze the unique properties of each film type. Seldom seen cloud free, the Falkland Islands lie off the southern coast of Argentina. The cold Falklands Ocean Current keeps the islands chilly, ideal for sheep herding and fishing, the two main industries. Colonies of seals and penguins also thrive on the islands.

  5. The impact of the 1982-1983 El Niño-Southern Oscillation on seabirds in the Galapagos Islands, Ecuador

    NASA Astrophysics Data System (ADS)

    Valle, Carlos A.; Cruz, Felipe; Cruz, Justine B.; Merlen, Godfrey; Coulter, Malcolm C.

    1987-12-01

    October 1982 through July 1983, the Galapagos Islands experienced the strongest El Niño-Southern Oscillation (ENSO) event yet recorded, with heavy rains and a warm, unproductive ocean. During this period most seabirds did not breed, and many left the archipelago altogether. Dark-rumped petrels which did breed during the event demonstrated low growth rate of chicks. Censuses and observations demonstrated substantial population decreases of other seabirds during the ENSO. Magnificent frigate birds suffered decreased nesting success, while blue-footed boobies abandoned all nesting attempts. Total censuses of Galapagos penguins and flightless cormorants taken before and after the ENSO demonstrated declines of 77% and 49%, respectively. We discuss the seabird population declines during ENSO and their subsequent recovery.

  6. Relationship between regional changes of soil physical properties and volcanic stratigraphy on the southern slope of Batur volcano in the island of Bali, Indonesia

    NASA Astrophysics Data System (ADS)

    Tanaka, T.; Sunarta, N.

    1994-04-01

    The present paper shows the relationship between the regional changes of soil physical properties and the volcanic stratigraphy on the southern slope of Batur volcano in the island of Bali, Indonesia, from the hydrogeological point of view based on the data obtained from field observations and laboratory experiments. The Bali soils data showed marked differences in regional distribution and their characteristics are closely correlated to the distribution of the volcanic stratigraphy derived from the Batur volcanic activities with the eruption about 23,700 years ago. On the basis of these data, the hydrogeological situation of the slope are presented schematically and groundwater flow regimes on the slope, such as recharge and discharge areas, are also classified according to the hydrogeological information. These classifications of groundwater flow regimes are useful to consider the occurrence of hydrological phenomena such as springs and paddy field distributions observed on the slope.

  7. The influence of effusion rate and rheology on lava flow dynamics and morphology: A case study from the 1971 and 1988-1990 eruptions at Villarrica and Lonquimay volcanoes, Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Castruccio, Angelo; Contreras, María Angélica

    2016-11-01

    We analyzed two historical lava flows from the Southern Andes of Chile: The lava flows from the 1971 Villarrica volcano eruption and the 1988-1990 Lonquimay volcano eruption. The 1971 lava flow has a volume of 2.3 × 107 m3, a maximum length of 16.5 km and was emplaced in two days, with maximum effusion rates of 800 m3/s. The lava has a mean width of 150 m and thicknesses that decrease from 10 to 12 m at 5 km from the vent to 5-8 m at the flow front. The morphology is mainly 'a'ā. The 1988-1990 lava flow has a volume of 2.3 × 108 m3, a maximum length of 10.2 km and was emplaced in 330 days, with peak effusion rates of 80 m3/s. The flow has a mean width of 600 m and thicknesses that increase from 10 to 15 m near the vent to > 50 m at the front. The morphology varies from 'a'ā in proximal sectors to blocky in the rest of the flow. We modelled the advance rate and thickness of these flows assuming two possible dynamical regimes: An internal rheology regime modelled as a Herschel-Bulkley (HB) fluid and a Yield Strength in the Crust (YSC) regime. We compared our results with the widely used Newtonian and Bingham rheologies. Our results indicate that the 1971 flow can be modelled either by the HB, Bingham or Newtonian rheologies using a single temperature, while the 1988-1990 flow was controlled by the YSC regime. Our analysis and comparison of models shows that care should be taken when modelling a lava flow, as different rheologies and assumptions can reach the same results in terms of advance rate and flow thickness. These examples suggest that the crustal strength should be taken into account in any model of lava flow advance.

  8. Seasonal variation in dry weight and elemental composition of the early developmental stages of Petrolisthes laevigatus (Guérin, 1835) (Decapoda: Porcellanidae) in the Seno de Reloncaví, southern Chile

    NASA Astrophysics Data System (ADS)

    Gebauer, P.; Paschke, K.; Barría, A.; Anger, K.

    2013-03-01

    In the Seno de Reloncaví, southern Chile, seasonal changes in dry weight (DW) and elemental composition (CHN) were studied in embryo (initial embryonic stage), newly hatched zoeae, and newly settled megalopae of a porcelain crab, Petrolisthes laevigatus. Samples were taken throughout the seasons of egg laying (March-December), hatching (August-February), and settlement (October-February). Values of DW and CHN per embryo or larva, respectively, were consistently minimum in the middle of each season and maximum near its beginning and end. Patterns of seasonal variation in early embryonic biomass may thus be carried over to larvae at hatching and, possibly, to the settlement stage. Such carry-over effects may be selectively advantageous, as zoeae released at the beginning or near the end of the hatching season face conditions of poor planktonic food availability in combination with low winter temperatures or decreasing temperatures at the end of summer (enforcing long development duration). Hence, an enhanced female energy allocation into egg production may subsequently translate to enhanced yolk reserves remaining at hatching, allowing for a larval development under unfavourable winter conditions. In summer, by contrast, plankton productivity and temperatures are generally high, allowing for fast larval growth and development. This coincides with minimal biomass and energy contents both at hatching and settlement. In conclusion, our data suggest that seasonal patterns in the biomass of early developmental stages of P. laevigatus may reflect phenotypic variability as an adaptive response to predictable variations in environmental conditions, allowing this species to reproduce in temperate regions with marked seasonality in water temperature and plankton productivity.

  9. First complete mitochondrial genome data from ancient South American camelids - The mystery of the chilihueques from Isla Mocha (Chile).

    PubMed

    Westbury, Michael; Prost, Stefan; Seelenfreund, Andrea; Ramírez, José-Miguel; Matisoo-Smith, Elizabeth A; Knapp, Michael

    2016-12-08

    In South American societies, domesticated camelids were of great cultural importance and subject to trade and translocation. South American camelids were even found on remote and hard to reach islands, emphasizing their importance to historic and pre-historic South American populations. Isla Mocha, a volcanic island 35 km offshore of Central-South Chile, is an example of such an island. When Dutch and Spanish explorers reached the island in the early 17th century, they found that domesticated camelids called "chilihueque" played a major role in the island's society. The origin and taxonomy of these enigmatic camelids is unclear and controversial. This study aims to resolve this controversy through genetic analyses of Isla Mocha camelid remains dating from pre-Columbian to early historic times. A recent archaeological excavation of site P21-3 on Isla Mocha yielded a number of camelid remains. Three complete mitochondrial genomes were successfully recovered and analysed. Phylogenetic analyses suggest that "chilihueque" was a local term for a domesticated guanaco. Results from phylogeographic analyses are consistent with Isla Mocha camelids being sourced from Southern Chilean guanaco populations. Our data highlights the capability of ancient DNA to answer questions about extinct populations which includes species identity, potential translocation events and origins of founding individuals.

  10. The Alaska Mineral Resource Assessment Program; background information to accompany geologic and mineral-resource maps of the Cordova and Middleton Island quadrangles, southern Alaska

    USGS Publications Warehouse

    Winkler, Gary R.; Plafker, George; Goldfarb, R.J.; Case, J.E.

    1992-01-01

    report summarizes recent results of integrated geological, geochemical, and geophysical field and laboratory studies conducted by the U.S. Geological Survey in the Cordova and Middleton Island 1?x3 ? quadrangles of coastal southern Alaska. Published open-file reports and maps accompanied by descriptive and interpretative texts, tables, diagrams, and pertinent references provide background information for a mineral-resource assessment of the two quadrangles. Mines in the Cordova and Middleton Island quadrangles produced copper and byproduct gold and silver in the first three decades of the 20th century. The quadrangles may contain potentially significant undiscovered resources of precious and base metals (gold, silver, copper, zinc, and lead) in veins and massive sulfide deposits hosted by Cretaceous and Paleogene sedimentary and volcanic rocks. Resources of manganese also may be present in the Paleogene rocks; uranium resources may be present in Eocene granitic rocks; and placer gold may be present in beach sands near the mouth of the Copper River, in alluvial sands within the canyons of the Copper River, and in smaller alluvial deposits underlain by rocks of the Valdez Group. Significant coal resources are present in the Bering River area, but difficult access and structural complexities have discouraged development. Investigation of numerous oil and gas seeps near Katalla in the eastern part of the area led to the discovery of a small, shallow field from which oil was produced between 1902 and 1933. The field has been inactive since, and subsequent exploration and drilling onshore near Katalla in the 1960's and offshore near Middleton Island on the outer continental shelf in the 1970's and 1980's was not successful.

  11. Long-distance island hopping without dispersal stages: transportation across major zoogeographic barriers in a Southern Ocean isopod

    NASA Astrophysics Data System (ADS)

    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.

  12. Eso's Situation in Chile

    NASA Astrophysics Data System (ADS)

    1995-02-01

    ESO, the European Southern Observatory, in reply to questions raised by the international media, as well as an ongoing debate about the so-called "Paranal case" in Chilean newspapers, would like to make a number of related observations concerning its status and continued operation in that country [1]. THE ESO OBSERVATORY SITES IN CHILE The European Southern Observatory, an international organisation established and supported by eight European countries, has been operating more than 30 years in the Republic of Chile. Here ESO maintains one of the world's prime astronomical observatories on the La Silla mountain in the southern part of the Atacama desert. This location is in the Fourth Chilean Region, some 600 km north of Santiago de Chile. In order to protect the La Silla site against dust and light pollution from possible future mining industries, roads and settlements, ESO early acquired the territory around this site. It totals about 825 sq. km and has effectively contributed to the preservation of its continued, excellent "astronomical" quality. Each year, more than 500 astronomers from European countries, Chile and elsewhere profit from this when they come to La Silla to observe with one or more of the 15 telescopes now located there. In 1987, the ESO Council [2] decided to embark upon one of the most prestigious and technologically advanced projects ever conceived in astronomy, the Very Large Telescope (VLT). It will consist of four interconnected 8.2-metre telescopes and will become the largest optical telescope in the world when it is ready. It is safe to predict that many exciting discoveries will be made with this instrument, and it will undoubtedly play a very important role in our exploration of the distant universe and its many mysteries during the coming decades. THE VLT AND PARANAL In order to find the best site for the VLT, ESO performed a thorough investigation of many possible mountain tops, both near La Silla and in Northern Chile. They showed

  13. New records to Chile of the Family Paraonidae (Annelida: Polychaeta)

    NASA Astrophysics Data System (ADS)

    Montiel, Américo; Hilbig, Brigitte; Rozbaczylo, Nicolás

    2002-06-01

    The Paraonidae are a polychaete family of small body size which have not been reported for Chile until recently. Mainly due to improved sample-processing methods, research campaigns carried out in 1994 and 1996 on three areas off southern Chile have yielded numerous records. Several species proved to be new to the Chilean polychaete fauna, including species that have been known previously only from Antarctic areas. These new records and range extensions are reported in this paper.

  14. Building capacity for HIV/AIDS prevention among Asian Pacific Islander organizations: the experience of a culturally appropriate capacity-building program in Southern California.

    PubMed

    Takahashi, Lois M; Candelario, Jury; Young, Tim; Mediano, Elizabeth

    2007-01-01

    This article has two goals: (1) to outline a conceptual model for culturally appropriate HIV prevention capacity building; (2) to present the experiences from a 3-year program provided by Asian Pacific AIDS Intervention Team to Asian Pacific Islander (API) organizations in southern California. The participating organizations were of two types: lesbian, gay, bisexual, transgender, and questioning (LGBTQ) social organizations and social service agencies not targeting LGBTQ. These organizations were selected for participation because of their commitment to HIV/AIDS issues in API communities. An organizational survey and staff observations were used to explore changes in capacity. The organizations were mostly small, targeted diverse populations, served a large geographic area (southern California as a region), and were knowledgeable about HIV. Organizations became more viable (more capacity in human resources, financial, external relations, and strategic management), but also more unstable (large growth in paid staff and board members), and showed more capacity in HIV knowledge environments (especially less stigma and more sensitivity to diverse populations). The results suggest that capacity can expand over a short period of time, but as capacity increases, organizational viability/stability and HIV knowledge environments change, meaning that different types of technical assistance would be needed for sustainability.

  15. Stable carbon and hydrogen isotopes in CH_{4} and light alkanes in magmatic and hydrothermal emissions from Vulcano Island (southern Italy)

    NASA Astrophysics Data System (ADS)

    Ricci, Andrea; Fiebig, Jens; Tassi, Franco; Vaselli, Orlando; Schreiber, Christoph; Caponi, Chiara; Hofmann, Sven; Capecchiacci, Francesco

    2017-04-01

    Vulcano Island, whose last eruption dates back to 1888-1890, is the southernmost island of the Aeolian Archipelago (southern Italy), a subduction-related volcanic arc in the Southern Tyrrhenian Sea. The active volcanic cone, namely La Fossa, displays an intense fumarolic activity, mostly occurring in its north-western sector. The fumaroles are characterized by outlet temperatures up to ˜400 ˚ C, and a typical magmatic composition with relatively high concentrations of HCl, HF and SO2. A second fumarolic area in the island occurs at Baia di Levante, the bay delimiting the eastern side of a flat isthmus that connects Vulcano to Vulcanello. In this area, low temperature (≤ 100˚ C) fumaroles and bubbling gases are discharged, displaying the typical hydrothermal-type composition, i.e. being characterized by relatively high contents of H2S and hydrocarbons and by the absence of acid gas constituents. We have investigated the chemical and isotopic (δ13C and δD) compositions of CH4 and light alkanes (C2H6, C3H8, C4H10) of the fumaroles venting from both the crater and the bay area. To the best of our knowledge, the isotopic data of CH4 from La Fossa crater presented in this work are the first ones on terrestrial high-temperature fumaroles ever reported. The main aim is to use these geochemical parameters to identify the fluid source(s) and the processes controlling the isotopic composition of the hydrocarbons. Our analytical results highlight that the δD-CH4 values of gases from La Fossa crater are extremely depleted in deuterium (down to -657‰ vs. V-SMOW), whereas those of the beach fumaroles range from -100‰ to -85‰ vs. V-SMOW. The 13C/12C ratios of CH4 and C2+ n-alkanes in the crater fumaroles also strongly differ from the isotopic signature measured in the hydrothermal gases, with the carbon isotopic composition of the low-temperature gases occurring significantly enriched in 13C relative to the magmatic gases. Assuming a deep source for light hydrocarbon

  16. Evidence for Cenozoic extensional basin development and tectonic inversion south of the flat-slab segment, southern Central Andes, Chile (33° 36°S.L.)

    NASA Astrophysics Data System (ADS)

    Charrier, R.; Baeza, O.; Elgueta, S.; Flynn, J. J.; Gans, P.; Kay, S. M.; Muñoz, N.; Wyss, A. R.; Zurita, E.

    2002-04-01

    The mainly volcanic Cenozoic deposits that make up much of the western part of the Principal Cordillera in Central Chile are generally subdivided into two major units: an older Abanico or Coya-Machalı´ Formation and a younger Farellones Formation. Difficulty in differentiating these units has led to considerable debate. On the basis of the wide distribution, great thickness, and presence of sedimentary intercalations, it has been postulated that these arc volcanics were deposited in an intermontane basin; more recently, it has been proposed that this basin developed under extensional conditions and underwent subsequent tectonic inversion. We present field, geochronologic, geochemical, and thermal maturity data that support the latter interpretation. Collectively, this new information clarifies the stratigraphic, tectonic, and paleogeographic evolution of these deposits. The vast geographic extent of the Abanico Formation and lateral equivalents, which reach from at least 32°30' to 44°S along the Principal Cordillera, its great thickness, and the presence of repeated thick fluvial and lacustrine intercalations all indicate deposition in a large, strongly subsident, and probably north-south oriented basin, developed between middle to late Eocene and Oligocene. The unconformable contact with underlying Mesozoic units observed at several localities indicates that deposition followed a substantial erosional episode during late Cretaceous and/or early Cenozoic time. Basal deposits of the Abanico Formation near Termas del Flaco increase rapidly in thickness to the west. Still further to the west, a thick Abanico section contains, in its upper part, mammal fossils older than those found in the basal deposits near Termas. This evidence indicates a major space of deposition west of this locality, which had been filled before deposition took place at Termas. The east-vergent, high-angle El Fierro thrust fault on the east side of the westward-growing deposits is

  17. Assessment of climatic and seismic cycles in southern chile from high resolution XRF and magnetic susceptibility measurements of historic lake sediments.

    NASA Astrophysics Data System (ADS)

    Boes, X.; Hubert-Ferrari, A.; Fagel, N.

    2006-12-01

    The high-resolution sedimentological studies performed on the sediment cores collected in the oceans or in the lakes constitutes the basis for inter-comparison of past climate variability. Among the new high-resolution approaches, the X-Ray Fluorescence (XRF) analysis of varved marine and lacustrine cores represents some of the best resolution. These data are particularly useful for tracking short-term climate changes expressed with calibrated time scales. However, the XRF results obtain on the fresh cores surface may be of low resolution because the core material is wet and unconsolidated. One particularly attractive method to solve this problem consists of impregnating the sediment cores with polymers in order to polish the core surface for XRF analyses. This step is essential for being able to get significant XRF and Magnetic Susceptibility (MS) results in the muddy cores. Since the 1960s, the evolution of sediment impregnation methods has been strongly linked to the development of innovative techniques (e.g., sampling devices, cryogenic and vacuum technologies, polymers, etc.). In this communication, we first propose a revised method that may be applied to prepare sediment cores for high-resolution XRF and MS data acquisition. Then we show an example of XRF and MS results obtain on laminated lake sediments from South America (Lago Puyehue, 40°S). As this area is very sensitive in terms of precipitation change (i.e., Southern Westerlies); the XRF data are compared with the regional instrumental precipitation database. The results are discussed in terms of climate and sismo- tectonic impacts over historic times. Our results shows that, in order to better interpret XRF tool over long sequences, the measurements should be first "calibrated" according to instrumental data such as precipitation, temperatures, and earthquake magnitudes.

  18. Ice-sheet control of continental erosion in central and southern Chile (36°-41°S) over the last 30,000 years

    NASA Astrophysics Data System (ADS)

    Muratli, Jesse M.; Chase, Zanna; McManus, James; Mix, Alan

    2010-11-01

    Bulk sediment chemistry from three Chilean continental margin Ocean Drilling Program sites constrains regional continental erosion over the past 30,000 years. Sediments from thirteen rivers that drain the (mostly igneous) Andes and the (mostly metamorphic) Coast Range, along with existing rock chemistry datasets, define terrestrial provenance for the continental margin sediments. Andean river sediments have high Mg/Al relative to Coast-Range river sediments. Near 36°S, marine sediments have high-Mg/Al (i.e. more Andean) sources during the last glacial period, and lower-Mg/Al (less Andean) sources during the Holocene. Near 41°S a Ti-rich source, likely from coast-range igneous intrusions, is prevalent during Holocene time, whereas high-Mg/Al Andean sources are more prevalent during the last glacial period. We infer that there is a dominant ice-sheet control of sediment sources. At 36°S, Andean-sourced sediment decreased as Andean mountain glaciers retreated after ˜17.6 ka, coincident with local oceanic warming and southward retreat of the Patagonian Forest and, by inference, westerly winds. At 41°S Andean sediment dominance peaks and then rapidly declines at ˜19 ka, coincident with local oceanic warming and the earliest deglacial sea-level rise. We hypothesize that this decreased flux of Andean material in the south is related to rapid retreat of the marine-based portion of the Patagonian Ice Sheet in response to global sea-level rise, as the resulting flooding of the southern portion of the Central Valley created a sink for Andean sediments in this region. Reversal of the decreasing deglacial Mg/Al trend at 41°S from 14.5 to 13.0 ka is consistent with a brief re-advance of the Patagonian ice sheet coincident with the Antarctic Cold Reversal.

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

    NASA Astrophysics Data System (ADS)

    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

  20. Contrasting records from mantle to surface of Holocene lavas of two nearby arc volcanic complexes: Caburgua-Huelemolle Small Eruptive Centers and Villarrica Volcano, Southern Chile

    NASA Astrophysics Data System (ADS)

    Morgado, E.; Parada, M. A.; Contreras, C.; Castruccio, A.; Gutiérrez, F.; McGee, L. E.

    2015-11-01

    Most of the small eruptive centers of the Andean Southern Volcanic Zone are built over the Liquiñe-Ofqui Fault Zone (LOFZ), a NS strike-slip (> 1000 km length) major structure, and close to large stratovolcanoes. This contribution compares textural features, compositional parameters, and pre- and syn-eruptive P,T conditions, between basaltic lavas of the Caburgua-Huelemolle Small Eruptive Centers (CHSEC) and the 1971 basaltic andesite lava of the Villarrica Volcano located 10 km south of the CHSEC. Olivines and clinopyroxenes occur as phenocrysts and forming crystal clots of the studied lavas. They do not markedly show compositional differences, except for the more scattered composition of the CHSEC clinopyroxenes. Plagioclase in CHSEC lavas mainly occur as phenocrysts or as microlites in a glass-free matrix. Two groups of plagioclase phenocrysts were identified in the 1971 Villarrica lava based on crystal size, disequilibrium features and zonation patterns. Most of the CHSEC samples exhibit higher LaN/YbN and more scattered Sr-Nd values than 1971 Villarrica lava samples, which are clustered at higher 143Nd/144Nd values. Pre-eruptive temperatures of the CHSEC-type reservoir between 1162 and 1165 ± 6 °C and pressures between 10.8 and 11.4 ± 1.7 kb consistent with a deep-seated reservoir were obtained from olivine-augite phenocrysts. Conversely, olivine-augite phenocrysts of 1971 Villarrica lava samples record pre-eruptive conditions of two stages or pauses in the magma ascent to the surface: 1208 ± 6 °C and 6.3-8.1 kb ± 1.7 kb (deep-seated reservoir) and 1164-1175 ± 6 °C and ≤ 1.4 kb (shallow reservoir). At shallow reservoir conditions a magma heating prior to the 1971 Villarrica eruption is recorded in plagioclase phenocrysts. Syn-eruptive temperatures of 1081-1133 ± 6 °C and 1123-1148 ± 6 °C were obtained in CHSEC and 1971 Villarrica lava, respectively using equilibrium olivine-augite microlite pairs. The LOFZ could facilitate a direct transport to

  1. The interplay between fault-fracture networks activity, fluid flow and mineralization in the Andes: A case study in the Tolhuaca geothermal system, southern Chile

    NASA Astrophysics Data System (ADS)

    Sanchez, P.; Perez-Flores, P.; Reich, M.; Arancibia, G.; Cembrano, J. M.

    2013-05-01

    The nature of the interplay between active tectonics and fluid flow is a key feature to better understand the chemical evolution of fluids in geothermal and hydrothermal systems. The prominent hydrothermal, tectonic and volcanic activity of the Southern Andes volcanic zone (SVZ) makes it one of the best natural laboratories to address this issue. In the northern termination of the Liquiñe-Ofqui Fault System (LOFS), tectonic and volcanic processes interact to define the geothermal field of Tolhuaca. The objective of our current research is to assess the nature of the interplay between brittle deformation and chemical evolution of fluids and mineral paragenesis. Tol-1 is a vertical 1.080 m deep borehole which could yield relevant information regarding the evolution of the Tolhuaca geothermal system. The methodology to achieve our objective includes the structural and geochemical analysis of oriented faults, fault-veins and veins -former pathways- in the core. Structural mapping at the regional scale will help to identify the main structural system, which accommodates the regional stresses, and promotes fluid migration, accumulation and arrest. Fluid inclusions analysis by microthermometry, LA-ICP-MS and Raman spectroscopy will allow a better understanding of the feedback between the fluid flow episodes and the mineralization. More than 120 structural measurements of faults, veins and fault-veins were performed (strike, dip, rake -when available-). Forty seven samples were taken for thin & fluid inclusions sections. Detailed mapping of structures including dip and kinematic indicators from mineral sealing was synthesized in a structural log of Tol-1 core. Our preliminary results show that there is a strong correlation between abundance of structures and rock type. Lava intervals exhibit more intense fracturing and veining than tuff and volcaniclastic intervals. In the upper 300 m of the core, structures are primarily steeply dipping with a dominant normal sense of

  2. The 2011 Hudson volcano eruption (Southern Andes, Chile): Pre-eruptive inflation and hotspots observed with InSAR and thermal imagery

    NASA Astrophysics Data System (ADS)

    Delgado, Francisco; Pritchard, Matthew; Lohman, Rowena; Naranjo, José Antonio

    2014-05-01

    Hudson is one of the most active volcanoes in the Southern Andes—it had one of the largest eruptions of the 20th century in 1991 (VEI = 5) and smaller eruptions in 1971 (VEI = 3), maybe 1973, and 2011 (VEI of 1-2). We use satellite-based interferometric synthetic aperture radar (InSAR) and thermal imagery to characterize the activity of Hudson between 2004 and 2011 and during the 2011 eruption. InSAR data show that the volcano inflated between 2004 and 2010 with a maximum change rate of between 2 and 3 cm/yr—about half of the deformation rate observed during a previous deformation episode from 1993-1999. Inversion for an inflating point source suggests magma accumulation beneath the SW part of the caldera at an average depth of 10 km. This inferred source is deeper than both the sources estimated for the magma chamber of the 1991 eruption (from petrology) and for the 1993-1999 deformation event. Also, the deformation from 2004-2010 is centered at a slightly different location and has a smaller volume change than that between 1993-1999—further indicating that there is either a large magma reservoir or several separate ones. While the deformation center is a few km from the eruption location near the caldera rim, the two are possibly linked since the predicted static Coloumb stress changes due to the inferred inflation source would encourage unclamping on potential faults in the caldera rim. We also analize nighttime satellite thermal images from MODIS and ASTER. While MODIS did not show any unambiguous evidence for hot spots, ASTER thermal imagery show that at least four months before the eruption there were locations with temperatures 7-8ºK above background. Lahars observed by helicopter overflights on 4 March 2011 and October 2011 suggest that the hotspots may have been caused by lakes or subglacial melting. There is no InSAR data available for the months immediately preceding the eruption, but the ASTER thermal imagery results may indicate an increase in

  3. Structural Controls on Helium, Nitrogen and Carbon Isotope Signatures in Geothermal Fluids Along the Liquiñe-Ofqui Fault System, Southern Chile.

    NASA Astrophysics Data System (ADS)

    Tardani, D.; Reich, M.; Roulleau, E.; Sano, Y.; Takahata, N.; Perez-Flores, P.; Sanchez-Alfaro, P.; Cembrano, J. M.; Arancibia, G.

    2016-12-01

    There is a general agreement that fault-fracture meshes exert a primary control on fluid flow in both volcanic/magmatic and geothermal/hydrothermal systems. In the Southern Volcanic Zone (SVZ) of the Chilean Andes, both volcanism and hydrothermal activity are spatially controlled by the Liquiñe-Ofqui Fault System (LOFS), an intra-arc, strike-slip fault, and by the Arc-oblique Long-lived Basement Fault System (ALFS), a set of transpressive NW-striking faults. However, the role that principal and subsidiary fault systems exert on magma degassing, hydrothermal fluid flow and fluid compositions remains poorly constrained. In this study we report new helium, carbon and nitrogen isotope data (3He/4He, d13C-CO2 and d15N) of a suite of fumarole and hot spring gas samples from 23 volcanic/geothermal localities that are spatially associated with either the LOFS or the ALFS in the central part of the SVZ. The dataset is characterized by a wide range of 3He/4He ratios (3.39 Ra to 7.53 Ra, where Ra = (3He/4He)air), d13C-CO2 values (-7.44‰ to -49.41‰) and d15N values (0.02‰to 4.93‰). The regional variations in 3He/4He, d13C-CO2 and d15N values are consistent with those reported for 87Sr/86Sr in lavas along the studied segment, which are controlled by the regional faults distribution. Two samples associated with the northern transtensional termination of the LOFS are the only datapoints showing pure MORB-like helium signatures. Whereas, towards the south the mantle-derived helium mixed with radiogenic component derived from magmatic assimilation of 4He-rich country rocks or contamination during the passage of the fluids through the upper crust. The degree of 4He contamination is related with the faults controlling the occurrence of volcanic and geothermal systems, with the most contaminated values associated with NW-striking structures. This is confirmed by d15N values that show increased mixing with crustal sediments and meteoric waters along NW faults (AFLS), while d13

  4. The Oldest, Slowest Rainforests in the World? Massive Biomass and Slow Carbon Dynamics of Fitzroya cupressoides Temperate Forests in Southern Chile.

    PubMed

    Urrutia-Jalabert, Rocio; Malhi, Yadvinder; Lara, Antonio

    2015-01-01

    Old-growth temperate rainforests are, per unit area, the largest and most long-lived stores of carbon in the terrestrial biosphere, but their carbon dynamics have rarely been described. The endangered Fitzroya cupressoides forests of southern South America include stands that are probably the oldest dense forest stands in the world, with long-lived trees and high standing biomass. We assess and compare aboveground biomass, and provide the first estimates of net primary productivity (NPP), carbon allocation and mean wood residence time in medium-age stands in the Alerce Costero National Park (AC) in the Coastal Range and in old-growth forests in the Alerce Andino National Park (AA) in the Andean Cordillera. Aboveground live biomass was 113-114 Mg C ha(-1) and 448-517 Mg C ha(-1) in AC and AA, respectively. Aboveground productivity was 3.35-3.36 Mg C ha(-1) year(-1) in AC and 2.22-2.54 Mg C ha(-1) year(-1) in AA, values generally lower than others reported for temperate wet forests worldwide, mainly due to the low woody growth of Fitzroya. NPP was 4.21-4.24 and 3.78-4.10 Mg C ha(-1) year(-1) in AC and AA, respectively. Estimated mean wood residence time was a minimum of 539-640 years for the whole forest in the Andes and 1368-1393 years for only Fitzroya in this site. Our biomass estimates for the Andes place these ecosystems among the most massive forests in the world. Differences in biomass production between sites seem mostly apparent as differences in allocation rather than productivity. Residence time estimates for Fitzroya are the highest reported for any species and carbon dynamics in these forests are the slowest reported for wet forests worldwide. Although primary productivity is low in Fitzroya forests, they probably act as ongoing biomass carbon sinks on long-term timescales due to their low mortality rates and exceptionally long residence times that allow biomass to be accumulated for millennia.

  5. The Oldest, Slowest Rainforests in the World? Massive Biomass and Slow Carbon Dynamics of Fitzroya cupressoides Temperate Forests in Southern Chile

    PubMed Central

    Urrutia-Jalabert, Rocio; Malhi, Yadvinder; Lara, Antonio

    2015-01-01

    Old-growth temperate rainforests are, per unit area, the largest and most long-lived stores of carbon in the terrestrial biosphere, but their carbon dynamics have rarely been described. The endangered Fitzroya cupressoides forests of southern South America include stands that are probably the oldest dense forest stands in the world, with long-lived trees and high standing biomass. We assess and compare aboveground biomass, and provide the first estimates of net primary productivity (NPP), carbon allocation and mean wood residence time in medium-age stands in the Alerce Costero National Park (AC) in the Coastal Range and in old-growth forests in the Alerce Andino National Park (AA) in the Andean Cordillera. Aboveground live biomass was 113–114 Mg C ha-1 and 448–517 Mg C ha-1 in AC and AA, respectively. Aboveground productivity was 3.35–3.36 Mg C ha-1 year-1 in AC and 2.22–2.54 Mg C ha-1 year-1 in AA, values generally lower than others reported for temperate wet forests worldwide, mainly due to the low woody growth of Fitzroya. NPP was 4.21–4.24 and 3.78–4.10 Mg C ha-1 year-1 in AC and AA, respectively. Estimated mean wood residence time was a minimum of 539–640 years for the whole forest in the Andes and 1368–1393 years for only Fitzroya in this site. Our biomass estimates for the Andes place these ecosystems among the most massive forests in the world. Differences in biomass production between sites seem mostly apparent as differences in allocation rather than productivity. Residence time estimates for Fitzroya are the highest reported for any species and carbon dynamics in these forests are the slowest reported for wet forests worldwide. Although primary productivity is low in Fitzroya forests, they probably act as ongoing biomass carbon sinks on long-term timescales due to their low mortality rates and exceptionally long residence times that allow biomass to be accumulated for millennia. PMID:26353111

  6. Nearshore benthic habitat GIS for the Channel Islands National Sanctuary and southern California State Fisheries Reserves. Volume 1

    USGS Publications Warehouse

    Cochrane, Guy R.; Nasby, Nicole M.; Reid, Jane A.; Waltenberger, Ben; Lee, Kristen M.

    2003-01-01

    The nearshore benthic habitat of the Santa Barbara coast and Channel Islands supports diverse marine life that is commercially, recreationally, and intrinsically valuable. Some of these resources are known to be endangered including a variety of rockfish and the white abalone. Agencies of the state of California and the United States have been mandated to preserve and enhance these resources. Data from sidescan sonar, bathymetry, video and dive observations, and physical samples are consolidated in a geographic information system (GIS). The GIS provides researchers and policymakers a view of the relationship among data sets to assist scienctific research and to help with economic and social policy-making decisions regarding this protected environment.

  7. The 2011 Cerro Hudson volcano eruption (Southern Andes, Chile): Pre-eruptive inflation and hot spots observed with InSAR and thermal imagery

    NASA Astrophysics Data System (ADS)

    Delgado, F.; Pritchard, M. E.; Lohman, R. B.

    2013-12-01

    Cerro Hudson is one of most active volcanoes of the Southern Andes with at least 12 documented Holocene eruptions including two large caldera forming eruptions (VEI>6) at 6700 and 3600 years BP and one of the largest eruptions of the 20th century in 1991 -- VEI of 5 and ~2.7 km3 of dense rock equivalent erupted material. The volcano had smaller eruptions in 1971 (VEI 3) and 2011 (VEI of 1-2), but despite its persistent activity, there is little monitoring because of its remote location. In this work we focus on remote sensing observations to better characterize the activity of Cerro Hudson between the 1991 and 2011 eruptions and during the 2011 eruption. Our primary technique is satellite-based interferometric synthetic aperture radar (InSAR). Although InSAR studies at Cerro Hudson are challenging given the poor data coverage as well as the presence of ice, snow and vegetation, the data show that the volcano inflated between 2004 and 2010 with a maximum range change rate between 2 and 3 cm/yr, about half of the deformation rate observed during a previously detected deformation episode from 1993-1999. Inversion for an inflating point source suggests magma accumulation beneath the SW part of the caldera at an average depth of 10 km -- deeper than the depths estimated for the magma chamber of the 1991 eruption (3 km) and a deformation event between 1993 and 1999 (5-6 km), and in a slightly different location with smaller volume changes. The center of deformation is located a few km away from the eruption location near the caldera ring fault, but the predicted static Coloumb stress changes due to the inferred inflation source would enhance motion on the caldera ring fault, suggesting that the deformation and eruptive vents may be linked. We also analize nighttime satellite thermal images from MODIS and ASTER for pixel-integrated temperatures above the background temperatures in the ice filled caldera. While MODIS did not show any unambiguous evidence for the eruption

  8. Design and application of a drip-type rainfall simulator adapted to steep topography and low intensity-rainfall characteristics in the Coastal Range of Southern Chile

    NASA Astrophysics Data System (ADS)

    Mohr, Christian; Anton, Huber

    2010-05-01

    Besides being adaptable for measuring infiltration, overland flow and sediment transport simultaneously, rainfall simulator systems allow the observation of the processes of runoff generation and soil erosion, too. This enables the assimilation of additional qualitative data and makes a rainfall simulator system a very valid method in the investigation of soil-hydrological response to precipitation events. In the present study a cheap, handy, transportable and easy to set up rainfall simulator applicable for the steep terrain conditions of the Southern Chilean Coastal range was designed based on Bowyer-Bower & Burt (1989). The used drip-type rainfall simulator had to fulfill two main requirements: adaptive to steep topography and little in water consumption. The used simulator is set up by a dismountable rectangular metal rack of 0.5x1.0m basal surface and 2.5m height. The metallic structure enables the attachment of plastic boards for wind protection. Fixable telescopic extensions allow a firm adjustment to slopes up to 45°. Horizontal metallic frames at different heights increase the stability of the structure and carry the devices of the rainfall simulator. On the uppermost frame, two containers provided with calibrated scales spend the water to a fast reacting receptacle assuring constant water supply and pressure by the Mariotte's principle. The rainfall intensity is adjusted by a control-panel according to the Bernoulli principle. This guarantees a constant water flow which was verified by the water-volume leaving the calibrated containers on top. Interchangeable glass-tubes of different diameters in the control-panel permit the generation of various precipitation intensities (4-60 mm/h; SD =0.16mm). The frame beneath carries an acrylic glass box with approx. 600 drop-formers (fishing line inside a 0.76mm Tygon-tube) at its bottom. 20 cm below, a framed 5mm-spacing-mesh serves as a raindrop randomizer. At the base of the simulator sheet metals avoid lateral

  9. Chile 1920-1980.

    ERIC Educational Resources Information Center

    Drake, Paul W.

    1981-01-01

    Annotated bibliography on the history of Chile during 60 years in the middle of the twentieth century is presented. A general outline of major Chilean developments during this period is presented to aid college level history instructors develop curriculum on Chile. Outline topics are the end of the Parliamentary Republic, 1920-31; popular front…

  10. Petrography and geochemistry of Cenozoic sedimentary sequences of the southern Samar Island, Philippines: Clues to the unroofing history of an ancient subduction zone

    NASA Astrophysics Data System (ADS)

    Pacle, Nichole Anthony D.; Dimalanta, Carla B.; Ramos, Noelynna T.; Payot, Betchaida D.; Faustino-Eslava, Decibel V.; Queaño, Karlo L.; Yumul, Graciano P.

    2017-07-01

    The Cenozoic sedimentary sequences of southern Samar Island in eastern Philippines were examined to understand the unroofing history of an ancient arc terrane. Petrographic and geochemical data revealed varying degrees of inputs from the ophiolite basement and differences in modal compositions. The sedimentary units are mostly made up of lithic fragments. The Late Oligocene to Early Miocene Daram Formation contains more chert and volcanic fragments whereas the late Middle Miocene to Early Pliocene Catbalogan Formation is dominantly composed of ultramafic components. These variances are correspondingly reflected in the geochemical signatures of these two sedimentary formations. The Catbalogan Formation clastic rocks have higher volatile-free MgO and Fe2O3 values (average: 8.4% for both oxides) compared to the Daram Formation samples (average: 5.1 and 6.3%, respectively). Geochemical variations are also reflected in the Co, Cr and Ni values: the Catbalogan Formation samples reflect higher concentrations (Co: 15-57 ppm; Cr: 231-1094 ppm; Ni: 84-484 ppm) compared to the Daram Formation samples (Co: 24-32 ppm; Cr: 234-418 ppm; Ni: 212-323 ppm). These observations suggest that the Daram Formation eroded and transported more of the crustal portions of the ophiolite, while the younger Catbalogan Formation represents a later exhumation and subsequent erosion of the ultramafic section. An oceanic island arc (OIA) setting is proposed for the two formations based on several tectonic discrimination diagrams (e.g., Th-La-Sc, La vs. Th). The OIA signature is further supported by their smooth chondrite-normalized rare earth element (REE) patterns with no obvious Eu anomaly as well as LREE enrichment which are typical of sediments deposited in OIA setting. Based on the dominantly ophiolitic provenance of the Daram and Catbalogan formations, the post-emplacement history of the nearby Samar Ophiolite is constrained during the Late Oligocene to Early Pliocene period.

  11. Microearthquake activity around Kueishantao island, offshore northeastern Taiwan: Insights into the volcano-tectonic interactions at the tip of the southern Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Konstantinou, K. I.; Pan, C.-Y.; Lin, C.-H.

    2013-05-01

    Kueishantao is a volcanic island located offshore the northeastern coast of Taiwan and lies at the tip of the southern Okinawa Trough which is the back-arc basin of the Ryukyu subduction zone. Its last eruption occurred during the Holocene (~ 7 ka), hence Kueishantao can be considered as an active volcano. In an effort to better understand how magmatic processes may interact with the regional tectonics, a seismic network was installed in the area during early January 2008. This network consisted of 16 three-component seismometers located both on Kueishantao and the coast of northeastern Taiwan. One year of data was analyzed yielding 425 earthquakes whose P and S arrival times were manually picked and each event was located using a nonlinear probabilistic location method. In order to improve the location accuracy, the minimum 1-D velocity model for this dataset was derived and all earthquakes were relocated using this model. The results show a tight cluster of events near Kueishantao while the remaining earthquakes are scattered between the island and mainland Taiwan. The majority of hypocentral depths range between 2.5 and 10 km where the former depth coincides with the bottom of the shallow sedimentary layer and the latter with the ductile lower crust. Waveforms of the three largest events were also inverted for the determination of their deviatoric and full moment tensor. No statistically significant isotropic component was found, while two of the events can be explained by a double-couple source. The third event exhibited a low frequency content (< 10 Hz) and a large non-double-couple component suggesting fluid involvement at its source. A stress inversion of all available focal mechanisms in the area shows that fluid circulation in the upper crust generates a local stress field around Kueishantao facilitating the opening of cracks along the NW-SE d