Economic conditions, hypertension, and cardiovascular disease: analysis of the Icelandic economic collapse.

PubMed

Birgisdóttir, Kristín Helga; Jónsson, Stefán Hrafn; Ásgeirsdóttir, Tinna Laufey

2017-12-01

Previous research has found a positive short-term relationship between the 2008 collapse and hypertension in Icelandic males. With Iceland's economy experiencing a phase of economic recovery, an opportunity to pursue a longer-term analysis of the collapse has emerged. Using data from a nationally representative sample, fixed-effect estimations and mediation analyses were performed to explore the relationship between the Icelandic economic collapse in 2008 and the longer-term impact on hypertension and cardiovascular health. A sensitivity analysis was carried out with pooled logit models estimated as well as an alternative dependent variable. Our attrition analysis revealed that results for cardiovascular diseases were affected by attrition, but not results from estimations on the relationship between the economic crisis and hypertension. When compared to the boom year 2007, our results point to an increased probability of Icelandic women having hypertension in the year 2012, when the Icelandic economy had recovered substantially from the economic collapse in 2008. This represents a deviation from pre-crisis trends, thus suggesting a true economic-recovery impact on hypertension.

Holocene evolution of aquatic bioactivity and terrestrial erosion inferred from Skorarvatn, Vestfirðir, Iceland: Where is the Little Ice Age?

NASA Astrophysics Data System (ADS)

Harning, D.; Geirsdottir, A.; Miller, G. H.

2016-12-01

Icelandic lake sediment is well suited to provide high-resolution, well-dated continuous archives of North Atlantic climate variability. We provide new insight into the Holocene climate evolution of Vestfirðir, NW Iceland, from a 10.3 ka multi-proxy lake sediment record from non-glacial lake Skorarvatn. Age control is derived from a combination of tephrochronology and 14C-dated macrofossils. Sediment samples were analyzed for both physical (MS, density) and biological (TC, TN, δ13C, δ15N, C/N, BSi) climate proxies, providing a sub-centennial record of aquatic bioactivity and terrestrial landscape stability, and hence, summer temperature. The lake basin was ice free by at least 10.3 ka yet the waning Icelandic Ice Sheet persisted in the catchment until 9.3 ka. The local Holocene Thermal Maximum (HTM), inferred from maximum aquatic bioactivity, spans 8.9 to 7.2 ka but was interrupted by significant cooling at 8.2 ka. In accordance with other Icelandic climate records documenting progressively cooler summers following the HTM, our record reveals reduced aquatic productivity and elevated terrestrial erosion toward the present. Superimposed on this 1st order trend are abrupt episodes of cooling, inferred from low aquatic bioactivity and/or enhanced landscape instability, at 6.4, 4.2, 3, 2.5 and 1.5 ka. Surprisingly, there is no clear indication of the Little Ice Age (LIA) in our record despite evidence for the local ice cap, Drangajökull, attaining maximum areal coverage at this time. Persistently low temperatures inferred from reduced aquatic productivity plateau at 2 ka whereas increasing terrestrial erosion ceases at 1 ka. Lack of a catchment erosion signal during the LIA may be the result of depleted catchment soils and/or perennially frozen ground preventing the mobilization of soil and vegetation. With the exception of the LIA, Skorarvatn's qualitative summer temperature record corresponds closely to summer sea surface temperature and sea ice records on the

Catalogue of Icelandic Volcanoes

NASA Astrophysics Data System (ADS)

Ilyinskaya, Evgenia; Larsen, Gudrun; Gudmundsson, Magnus T.; Vogfjord, Kristin; Pagneux, Emmanuel; Oddsson, Bjorn; Barsotti, Sara; Karlsdottir, Sigrun

2016-04-01

The Catalogue of Icelandic Volcanoes is a newly developed open-access web resource in English intended to serve as an official source of information about active volcanoes in Iceland and their characteristics. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland GOSVÁ (commenced in 2012), as well as being part of the effort of FUTUREVOLC (2012-2016) on establishing an Icelandic volcano supersite. Volcanic activity in Iceland occurs on volcanic systems that usually comprise a central volcano and fissure swarm. Over 30 systems have been active during the Holocene (the time since the end of the last glaciation - approximately the last 11,500 years). In the last 50 years, over 20 eruptions have occurred in Iceland displaying very varied activity in terms of eruption styles, eruptive environments, eruptive products and the distribution lava and tephra. Although basaltic eruptions are most common, the majority of eruptions are explosive, not the least due to magma-water interaction in ice-covered volcanoes. Extensive research has taken place on Icelandic volcanism, and the results reported in numerous scientific papers and other publications. In 2010, the International Civil Aviation Organisation (ICAO) funded a 3 year project to collate the current state of knowledge and create a comprehensive catalogue readily available to decision makers, stakeholders and the general public. The work on the Catalogue began in 2011, and was then further supported by the Icelandic government and the EU through the FP7 project FUTUREVOLC. The Catalogue of Icelandic Volcanoes is a collaboration of the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Civil Protection Department of the National Commissioner of the Iceland Police, with contributions from a large number of specialists in Iceland and elsewhere. The Catalogue is built up of chapters with texts and various

The Subject of Data in Submissions to the CLCS: Documenting the outer limits of the Northern Continental Shelf of the Faroe Islands

NASA Astrophysics Data System (ADS)

Vang Heinesen, Martin; Mørk, Finn

2017-04-01

The first partial submissions made by the Kingdom of Denmark, in respect of the continental shelf north of the Faroe Islands (North Faroe Margin, NFM), was submitted to the Commission on the Limits of the Continental Shelf in April 2009 as the result of 7 years of preparation which also included 4 additional continental shelf regions around the Faroe Islands and Greenland, on which individual partial submissions were made subsequently. The NFM covers parts of the NW European continental margin, it continues onto the Faroe-Iceland Ridge and the extinct Ægir (spreading) Ridge and overlaps with the continental margin of Iceland and Norway in the sediment rich Ægir Basin located between the European margin to the south and south-east, and the Jan Mayen Micro-continental margin to the west and north-west. Prior to the onset of the continental shelf project of the Kingdom of Denmark, arrangements had already been made with Norway and Iceland regarding the sharing of existing data and acquisition of new seismic data in the overlapping regions. Before that, the main database in the area included a comprehensive multi-beam bathymetric data set covering large parts of the Ægir Ridge with scattered single beam bathymetric lines in the remaining regions. It also comprised a number of single- and multi-channel seismic lines and a long refraction seismic line transecting the entire eastern part of the basin, from the Norwegian shelf to the Ægir Ridge, in addition to local side scan sonar and regional potential field data. During the project, additional high quality multi-channel seismic data, extensive multi-beam bathymetric data, and a comprehensive high resolution aeromagnetic dataset were acquired, allowing detailed mapping of the morphological and geological nature of the margin, including accurate identification of the base of the continental slope and mapping of the sediment thickness and sediment continuation in the basin. This data proved to be crucial for the

Trends in summer bottom-water temperatures on the northern Gulf of Mexico continental shelf from 1985 to 2015.

PubMed

Turner, R Eugene; Rabalais, Nancy N; Justić, Dubravko

2017-01-01

We quantified trends in the 1985 to 2015 summer bottom-water temperature on the northern Gulf of Mexico (nGOM) continental shelf for data collected at 88 stations with depths ranging from 3 to 63 m. The analysis was supplemented with monthly data collected from 1963 to 1965 in the same area. The seasonal summer peak in average bottom-water temperature varied concurrently with air temperature, but with a 2- to 5-month lag. The summer bottom-water temperature declined gradually with depth from 30 oC at stations closest to the shore, to 20 oC at the offshore edge of the study area, and increased an average 0.051 oC y-1 between1963 and 2015. The bottom-water warming in summer for all stations was 1.9 times faster compared to the rise in local summer air temperatures, and 6.4 times faster than the concurrent increase in annual global ocean sea surface temperatures. The annual rise in average summer bottom-water temperatures on the subtropical nGOM continental shelf is comparable to the few published temperature trend estimates from colder environments. These recent changes in the heat storage on the nGOM continental shelf will affect oxygen and carbon cycling, spatial distribution of fish and shrimp, and overall species diversity.

Trend and dynamic cause of sediment particle size on the adjacent continental shelf of the Yangtze Estuary

NASA Astrophysics Data System (ADS)

Yang, Yun-ping; Zhang, Ming-jin; Li, Yi-tian; Fan, Yong-yang

2016-12-01

Based on the measured data in recent 20 years, the variation trends of the median grain size of the surface sediment, the sand-silt boundary and the mud area on the adjacent continental shelf of the Yangtze Estuary were analyzed in depth, and the effects of natural mechanism and human activities were discussed. The results show that: (1) In recent years (2006-2013), the median grain size of sediment and the distribution pattern of grouped sediments in the adjacent continental shelf area to the Yangtze Estuary have presented no obvious change compared with those before 2006; (2) The median diameter of the surface sediment in the continental shelf area displayed a coarsening trend with the decrease of sediment discharge from the basin and the drop in suspended sediment concentration in the shore area; (3) In 2004-2007, the sand-silt boundary in the north part (31°30'N) of the continental shelf area presented no significant changes, while that in the south part (31°30'S) moved inwards; In 2008-2013, both the sand-silt boundaries in the north and south parts of the continental shelf area moved inwards, mainly due to the fact that in the dry season, a relatively enhanced hydrodynamic force of the tides was generated in the Yangtze River, as well as a decreased suspended sediment concentration and a flow along the banks in North Jiangsu; (4) The mud area where the maximum deposition rate is found in the Yangtze Estuary, tends to shrink due to the drop in sediment discharge from the basin, and the decrease in suspended sediment concentration in the shore area and erosion in the delta. Moreover, it tended to shift to the south at the same time because the implement of the training works on the deep-water channel of the North Passage changed the split ratio between the North and South Passages with an increase in the power of the discharged runoff in the South Passage.

Porosity-depth trends of carbonate deposits along the northwest shelf of Australia (IODP Expedition 356)

NASA Astrophysics Data System (ADS)

Lee, Eun Young; Kominz, Michelle; Reuning, Lars; Takayanagi, Hideko; Knierzinger, Wolfgang; Wagreich, Michael; Expedition 356 shipboard scientists, IODP

2017-04-01

The northwest shelf (NWS) of Australia extends from northern tropical to southern temperate latitudes situated offshore from the low-moderate-relief and semi-arid Australian continent. The shelf environment is dominated throughout by carbonate sedimentation with warm-water and tropical carbonate deposits, connected to the long-term northward drift of Australia bringing the NWS into tropical latitudes. IODP expedition 356 cored seven sites (U1458-U1464) covering a latitudinal range of 29°S-18°S off the NWS. This study focuses on porosity-depth trends of the Miocene - Pleistocene carbonate sediment on the NWS. The NWS is an ideal area to study regional (and furthermore general) carbonate porosity-depth relationships, because it contains a nearly continuous sequence of carbonate sediment ranging in depth from the surface to about 1,100m and in age from Pleistocene to Miocene. Porosity-depth trends of sedimentary rocks are generally controlled by a variety of factors which govern the rates of porosity loss due to mechanical compaction and of porosity loss (or gain) due to chemical processes during diagenesis. This study derives porosity data from Moisture and Density (MAD) technique conducted during IODP Expedition 356. MAD samples were collected from packstone (44%), wackestone (27%), mudstone (15%) and grainstone (7%), with the rest from floatstone, rudstone, dolostone, sandstone and other subordinate lithologies. To understand porosity-depth trends, the porosity data are arranged both exponentially and linearly, and correlated with age models and lithologic descriptions provided by IODP shipboard scientists. Porosity(%)-depth(m) trends of all the porosity data are Porosity=52e-0.0008/Depth (exponential) and Porosity=-0.03Depth+52 (linear). Porosities near surface and in the deepest parts of each well are least well represented by these trend lines. Porosity values of Pleistocene sediment are generally higher than those of Miocene - Pliocene sediment. The initial

The Language Situation in Iceland

ERIC Educational Resources Information Center

Hilmarsson-Dunn, Amanda; Kristinsson, Ari Pall

2010-01-01

Purist language policies in Iceland have preserved and modernized Icelandic up until the present time. However, the impact of globalization and global English has led to the perception that the language is less secure than in the past and has prompted efforts by policy makers towards greater protection of Icelandic. This monograph presents the…

Mineralogical influences on porosity-depth trends of shelf deposits (Miocene-Pleistocene) along the northwest shelf of Australia (IODP Expedition 356)

NASA Astrophysics Data System (ADS)

Knierzinger, Wolfgang; Lee, Eun Young; Wagreich, Michael

2017-04-01

Porosity in sediments is influenced by various factors such as mineralogical composition, burial depth, connate fluids, and stratigraphic layering. This work focuses on processes underlying porosity anomalies in carbonate shelf deposits along the northwest shelf of Australia by using different techniques (polarization microscopy, electron microscopy, XRD, XRF). IODP expedition 356 recovered cored seven sites (U1458-U1464), covering a latitudinal range of 29°S-18°S on the northwest shelf. Strong negative deviations from general porosity-depth trends for these carbonate rich sediments are clear for samples with higher contents of dolomite, calcium sulfates, and non-skeletal calcite. No significant influence of aragonite on porosity values has yet been detected. However, it is likely that the occurrence of high amounts of aragonite is a crucial element with regard to porosity values in these carbonate rich deposits, since elongated aragonite needles commonly enhance interparticle porosity. Further insight might be gained through the application of electron microscopy. In general, sediments in the northern part of the study area (Sites U1462, U1463, U1464) tend to show slightly higher porosity values compared to sediments form the south (Sites U1459, U1460). This may reflect the influence of calcium sulfate, because mineralogical analyses show, calcium sulfate is relatively rare at the southern sites, whereas higher amounts of calcium sulfates occur in the north. The lack of detrital particles in calcium sulfate components indicates an evaporitic origin. Deposits at Site U 1461 differ from other analyzed sediments insofar as higher amounts of feldspars and micas are apparent. *This research is conducted within the frame of the 'International Ocean Discovery Program', funded by the Ministry of Oceans and Fisheries, Korea.

Legalizing altruistic surrogacy in response to evasive travel? An Icelandic proposal.

PubMed

Kristinsson, Sigurður

2016-12-01

Surrogate motherhood has been prohibited by Icelandic law since 1996, but in recent years, Icelandic couples have sought transnational surrogacy in India and the United States despite uncertainties about legal parental status as they return to Iceland with infants born to surrogate mothers. This reflects global trends of increased reproductive tourism, which forces restrictive regimes not only to make decisions concerning the citizenship and parentage of children born to surrogate mothers abroad, but also to confront difficult moral issues concerning surrogacy, global justice, human rights and exploitation. In March 2015, a legislative proposal permitting altruistic surrogacy, subject to strict regulation and oversight, and prohibiting the solicitation of commercial surrogacy abroad, was presented in the Icelandic Parliament. The proposal aims to protect the interest of the child first, respect the autonomy of the surrogate second, and accommodate the intended parents' wishes third. After a brief overview of the development of the surrogacy issue in Iceland, this article describes the main features of this legislative proposal and evaluates it from an ethical and global justice perspective. It concludes that the proposed legislation is a response to problems generated by cross-border surrogacy in the context of evolving public attitudes toward the issue, and constitutes a valid attempt to reduce the moral hazards of surrogacy consistent with insights from current bioethical literature. Although the proposed legislation arguably represents an improvement over the current ban, however, difficult problems concerning evasive travel and global injustice are likely to persist until effective international coordination is achieved.

Interaction between central volcanoes and regional tectonics along divergent plate boundaries: Askja, Iceland

NASA Astrophysics Data System (ADS)

Trippanera, Daniele; Ruch, Joël; Acocella, Valerio; Thordarson, Thor; Urbani, Stefano

2018-01-01

Activity within magmatic divergent plate boundaries (MDPB) focuses along both regional fissure swarms and central volcanoes. An ideal place to investigate their mutual relationship is the Askja central volcano in Iceland. Askja consists of three nested calderas (namely Kollur, Askja and Öskjuvatn) located within a hyaloclastite massif along the NNE-SSW trending Icelandic MDPB. We performed an extensive field-based structural analysis supported by a remote sensing study of tectonic and volcanic features of Askja's calderas and of the eastern flank of the hyaloclastite massif. In the massif, volcano-tectonic structures trend N 10° E to N 40° E, but they vary around the Askja caldera being both parallel to the caldera rim and cross-cutting on the Western side. Structural trends around the Öskjuvatn caldera are typically rim parallel. Volcanic vents and dikes are preferentially distributed along the caldera ring faults; however, they follow the NNE-SSW regional structures when located outside the calderas. Our results highlight that the Askja volcano displays a balanced amount of regional (fissure-swarm related) and local (shallow-magma-chamber related) tectonic structures along with a mutual interaction among these. This is different from Krafla volcano (to the north of Askja) dominated by regional structures and Grímsvötn (to the South) dominated by local structures. Therefore, Askja represents an intermediate tectono-magmatic setting for volcanoes located in a slow divergent plate boundary. This is also likely in accordance with a northward increase in the spreading rate along the Icelandic MDPB.

Geographic Names of Iceland's Glaciers: Historic and Modern

USGS Publications Warehouse

Sigurðsson, Oddur; Williams, Richard S.

2008-01-01

Climatic changes and resulting glacier fluctuations alter landscapes. In the past, such changes were noted by local residents who often documented them in historic annals; eventually, glacier variations were recorded on maps and scientific reports. In Iceland, 10 glacier place-names are to be found in Icelandic sagas, and one of Iceland's ice caps, Snaefellsjokull, appeared on maps of Iceland published in the 16th century. In the late 17th century, the first description of eight of Iceland's glaciers was written. Therefore, Iceland distinguishes itself in having a more than 300-year history of observations by Icelanders on its glaciers. A long-term collaboration between Oddur Sigurdsson and Richard S. Williams, Jr., led to the authorship of three books on the glaciers of Iceland. Much effort has been devoted to documenting historical glacier research and related nomenclature and to physical descriptions of Icelandic glaciers by Icelanders and other scientists from as far back as the Saga Age to recent (2008) times. The first book, Icelandic Ice Mountains, was published by the Icelandic Literary Society in 2004 in cooperation with the Icelandic Glaciological Society and the International Glaciological Society. Icelandic Ice Mountains was a glacier treatise written by Sveinn Palsson in 1795 and is the first English translation of this important scientific document. Icelandic Ice Mountains includes a Preface, including a summary of the history and facsimiles of page(s) from the original manuscript, a handwritten copy, and an 1815 manuscript (without maps and drawings) by Sveinn Palsson on the same subject which he wrote for Rev. Ebenezer Henderson; an Editor's Introduction; 82 figures, including facsimiles of Sveinn Palsson's original maps and perspective drawings, maps, and photographs to illustrate the text; a comprehensive Index of Geographic Place-Names and Other Names in the treatise; References, and 415 Endnotes. Professional Paper 1746 (this book) is the second

MABEL Iceland 2012 Flight Report

NASA Technical Reports Server (NTRS)

Cook, William B.; Brunt, Kelly M.; De Marco, Eugenia L.; Reed, Daniel L.; Neumann, Thomas A.; Markus, Thorsten

2017-01-01

In March and April 2012, NASA conducted an airborne lidar campaign based out of Keflavik, Iceland, in support of Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) algorithm development. The survey targeted the Greenland Ice Sheet, Iceland ice caps, and sea ice in the Arctic Ocean during the winter season. Ultimately, the mission, MABEL Iceland 2012, including checkout and transit flights, conducted 14 science flights, for a total of over 80 flight hours over glaciers, icefields, and sea ice.

Variability in Organic-Carbon Sources and Sea-Ice Coverage North of Iceland (Subarctic) During the Past 15,000 Years

NASA Astrophysics Data System (ADS)

Xiao, X.; Zhao, M.; Knudsen, K. L.; Eiriksson, J.; Gudmundsdottir, E. R.; Jiang, H.; Guo, Z.

2017-12-01

Sea ice, prevailing in the polar region and characterized by distinct seasonal and interannual variability, plays a pivotal role in Earth's climate system (Thomas and Dieckmann, 2010). Studies of spatial and temporal changes in modern and past sea-ice occurrence may help to understand the processes controlling the recent decrease in Arctic sea-ice cover. Here, we determined the concentrations of sea-ice diatom-derived biomarker "IP25" (monoene highly-branched isoprenoid with 25 carbon atom; Belt et al., 2007), phytoplankton-derived biomarker brassicasterol and terrigenous biomarker long-chain n-alkanols in a sediment core from the North Icelandic shelf to reconstruct the high-resolution sea-ice variability and the organic-matter sources during the past 15,000 years. During the Bølling/Allerød, the North Icelandic shelf was characterized by extensive spring sea-ice cover linked to reduced flow of warm Atlantic Water and dominant Polar water influence; the input of terrestrial and sea-ice organic matters was high while the marine organic matter derived from phytoplankton productivity was low. Prolonged sea-ice cover with occasional occurrence of seasonal sea ice prevailed during the Younger Dryas interrupted by a brief interval of enhanced Irminger Current; the organic carbon input from sea-ice productivity, terrestrial matter and phytoplankton productivity all decreased. The seasonal sea ice decreased gradually from the Younger Dryas to the onset of the Holocene corresponding to increasing insolation. Therefore, the sea-ice productivity decreased but the phytoplankton productivity increased during this time interval. The biomarker records from this sediment core give insights into the variability in sea ice and organic-carbon sources in the Arctic marginal area during the last deglacial and Holocene. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Org. Geochem. 38, 16

Glacier recession in Iceland and Austria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, D.K.; Williams, R.S. Jr.; Bayr, K.J.

1992-03-01

It has been possible to measure glacier recession on the basis of Landsat data, in conjunction with comparisons of the magnitude of recession of a glacier margin with in situ measurements at fixed points along the same margin. Attention is presently given to the cases of Vatnajokull ice cap, in Iceland, and the Pasterze Glacier, in Austria, on the basis of satellite data from 1973-1987 and 1984-1990, respectively. Indications of a trend toward negative mass balance are noted. Nevertheless, while most of the world's small glaciers have been receding, some are advancing either due to local climate or the tidewatermore » glacier cycle. 21 refs.« less

Iceland

NASA Image and Video Library

2015-03-09

Iceland, dressed in winter white, peaked through a hole in a complex system of clouds in late February, 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured this true-color image on February 21 as it passed over the region. Ice and snow covers Iceland almost entirely, except for coastal regions in the southwest and southeast. The extensive, roughly H-shaped area in the southeast section of the island is Vatnajökull, Iceland’s largest glacier. Hidden underneath the ice lies Bardarbunga, a large subglacial stratovolcano. On August 31, 2014 the volcano began an eruption at two fissures to the north of the glacier and deposited a lava field that measured about 131 feet (40 meters) at its thickest points, and covered an area about 33 sq. mi (85 sq. km) by the time the eruption ended on February 27, 2015. The massive lava flow left its mark on Iceland – the cooled lava can be seen as the roughly oval black area to the north of the Vatnajökull glacier. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team 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

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

article title:  Ash from Eyjafjallajökull Volcano, Iceland Stretches over the North Atlantic   ... that occurred in late March 2010, the Eyjafjallajökull Volcano in Iceland began erupting again on April 14, 2010. The resulting ash ...

Färoe-Iceland Ridge Experiment: 1. Crustal structure of northeastern Iceland

USGS Publications Warehouse

Staples, Robert K.; White, Robert S.; Brandsdottir, Bryndis; Menke, William; Maguire, Peter K.H.; McBride, John H.

1997-01-01

Results from the Färoe-Iceland Ridge Experiment (FIRE) constrain the crustal thickness as 19 km under the Northern Volcanic Zone of Iceland and 35 km under older Tertiary areas of northeastern Iceland. The Moho is defined by strong P wave and S wave reflections. Synthetic seismogram modeling of the Moho reflection indicates mantle velocities of at least 8.0 km/s beneath the Tertiary areas of northeastern Iceland and at least 7.9 km/s beneath the neovolcanic zone. Crustal diving rays resolve the structure of the upper and lower crust. Surface P wave velocities are 1.1–4.0 km/s in Quaternary rocks and are rather higher, 4.4–4.7 km/s, in the Tertiary basalts that outcrop elsewhere. The highest crustal P wave velocities observed directly from diving rays are 7.1 km/s, from rays that turn at 24 km depth. Velocities of 7.35 km/s at the base of the crust are inferred from extrapolation of the lower crustal velocity gradient (0.024 s−1). A Poisson's ratio of approximately 0.27, equivalent to an S wave to P wave travel time ratio of 1.78, is measured throughout the crust east of the neovolcanic zone. The Poisson's ratio and the steep Moho topography (in places up to 30° from the horizontal) indicate that the entire crust outside the neovolcanic zone is cool (<800°C). Gravity data are well matched by a velocity/density conversion of our seismic crustal model and indicate a region of low mantle density beneath the neovolcanic zone, believed to be due to elevated mantle temperatures. The crustal thickness in the neovolcanic zone is consistent with geochemical estimates of the melt generation, placing constraints on the flow within the Iceland mantle plume.

Punctuated Holocene climate of Vestfirðir, Iceland, linked to internal/external variables and oceanographic conditions

NASA Astrophysics Data System (ADS)

Harning, David J.; Geirsdóttir, Áslaug; Miller, Gifford H.

2018-06-01

Emerging Holocene paleoclimate datasets point to a non-linear response of Icelandic climate against a background of steady orbital cooling. The Vestfirðir peninsula (NW Iceland) is an ideal target for continued climate reconstructions due to the presence of a small ice cap (Drangajökull) and numerous lakes, which provide two independent means to evaluate existing Icelandic climate records and to constrain the forcing mechanisms behind centennial-scale cold anomalies. Here, we present new evidence for Holocene expansions of Drangajökull based on 14C dates from entombed dead vegetation as well as two continuous Holocene lake sediment records. Lake sediments were analyzed for both bulk physical (MS) and biological (%TOC, δ13C, C/N, and BSi) parameters. Composite BSi and C/N records from the two lakes yield a sub-centennial qualitative perspective on algal (diatom) productivity and terrestrial landscape stability, respectively. The Vestfirðir lake proxies suggest initiation of the Holocene Thermal Maximum by ∼8.8 ka with subsequent and pronounced cooling not apparent until ∼3 ka. Synchronous periods of reduced algal productivity and accelerated landscape instability point to cold anomalies centered at ∼8.2, 6.6, 4.2, 3.3, 2.3, 1.8, 1, and 0.25 ka. Triggers for cold anomalies are linked to variable combinations of freshwater pulses, low total solar irradiance, explosive and effusive volcanism, and internal modes of climate variability, with cooling likely sustained by ocean/sea-ice feedbacks. The climate evolution reflected by our glacial and organic proxy records corresponds closely to marine records from the North Iceland Shelf.

Icelandic occupational therapists' attitudes towards educational issues.

PubMed

Asmundsd ttir, ELIN EBBA; Kaplan, SUSAN

2001-01-01

The purpose of this study was to assess the readiness of occupational therapists in Iceland to accept a professional as opposed to a technical view of the profession. Most Icelandic occupational therapists were educated in other countries, with little emphasis on liberal arts, sciences and research. The first Icelandic occupational therapy programme, a university-level programme, was founded in 1997. All Icelandic occupational therapists were surveyed. Eighty-seven questionnaires were sent out and 80 (92%) were returned and used for statistical analysis. The results of the study showed that Icelandic occupational therapists valued academic skills over technical skills, emphasizing occupational therapy theory unique to the profession and research to validate practice. More recognition among other health professionals was considered the most needed change in the profession. The results of the study showed that the clinicians' attitudes confirmed in general what is emphasized in the curriculum and in students' fieldwork. Further research is needed to explore whether the Icelandic occupational therapy profession succeeds in promoting research and recognition by other health professions.

Continental crust beneath southeast Iceland.

PubMed

Torsvik, Trond H; Amundsen, Hans E F; Trønnes, Reidar G; Doubrovine, Pavel V; Gaina, Carmen; Kusznir, Nick J; Steinberger, Bernhard; Corfu, Fernando; Ashwal, Lewis D; Griffin, William L; Werner, Stephanie C; Jamtveit, Bjørn

2015-04-14

The magmatic activity (0-16 Ma) in Iceland is linked to a deep mantle plume that has been active for the past 62 My. Icelandic and northeast Atlantic basalts contain variable proportions of two enriched components, interpreted as recycled oceanic crust supplied by the plume, and subcontinental lithospheric mantle derived from the nearby continental margins. A restricted area in southeast Iceland--and especially the Öræfajökull volcano--is characterized by a unique enriched-mantle component (EM2-like) with elevated (87)Sr/(86)Sr and (207)Pb/(204)Pb. Here, we demonstrate through modeling of Sr-Nd-Pb abundances and isotope ratios that the primitive Öræfajökull melts could have assimilated 2-6% of underlying continental crust before differentiating to more evolved melts. From inversion of gravity anomaly data (crustal thickness), analysis of regional magnetic data, and plate reconstructions, we propose that continental crust beneath southeast Iceland is part of ∼350-km-long and 70-km-wide extension of the Jan Mayen Microcontinent (JMM). The extended JMM was marginal to East Greenland but detached in the Early Eocene (between 52 and 47 Mya); by the Oligocene (27 Mya), all parts of the JMM permanently became part of the Eurasian plate following a westward ridge jump in the direction of the Iceland plume.

Long-term variability of dust events in Iceland (1949-2011)

NASA Astrophysics Data System (ADS)

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.

2014-06-01

Long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and merged with results obtained from the Northeast Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust. Including codes 04-06 into the criteria for dust observations, the frequency was 135 dust days annually. The Sea Level Pressure (SLP) oscillation controlled whether dust events occurred in NE (16.4 dust days annually) or in southern part of Iceland (about 18 dust days annually). The most dust-frequent decade in S Iceland was the 1960s while the most frequent decade in NE Iceland was the 2000s. A total of 32 severe dust storms (visibility < 500 m) was observed in Iceland with the highest frequency during the 2000s in S Iceland. The Arctic dust events (NE Iceland) were typically warm and during summer/autumn (May-September) while the Sub-Arctic dust events (S Iceland) were mainly cold and during winter/spring (March-May). About half of dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between PM10 concentrations and visibility during dust observations at the stations Vik and Storhofdi. This study shows that Iceland is among the dustiest areas of the world and dust is emitted the year-round.

Economic crisis and smoking behaviour: prospective cohort study in Iceland

PubMed Central

McClure, Christopher Bruce; Valdimarsdóttir, Unnur A; Hauksdóttir, Arna; Kawachi, Ichiro

2012-01-01

Objective To examine the associations between the 2008 economic collapse in Iceland and smoking behaviour at the national and individual levels. Design A population-based, prospective cohort study based on a mail survey (Health and Wellbeing in Iceland) assessed in 2007 and 2009. Setting National mail survey. Participants Representative cohort (n=3755) of Icelandic adults. Main outcome measure Smoking status. Results A significant reduction in the prevalence of smoking was observed from 2007 (pre-economic collapse) to 2009 (postcollapse) in both males (17.4–14.8%; p 0.01) and females (20.0–17.5%; p 0.01) in the cohort (n=3755). At the individual level of analysis, male former smokers experiencing a reduction in income during the same period were less likely to relapse (OR 0.37; 95% CI 0.16 to 0.85). Female smokers were less likely to quit over time compared to males (OR 0.65; 95% CI 0.45 to 0.93). Among male former smokers who experienced an increase in income between 2007 and 2009, we observed an elevated risk of smoking relapse (OR 4.02; 95% CI 1.15 to 14.00). Conclusions The national prevalence of smoking in Iceland declined following the 2008 economic crisis. This could be due to the procyclical relationship between macro-economic conditions and smoking behaviour (ie, hard times lead to less smoking because of lower affordability), or it may simply reflect a continuation of trends already in place prior to the crisis. In individual-level analysis, we find that former smokers who experienced a decline in income were less likely to relapse; and conversely, an increase in income raises the risk. However, caution is warranted since these findings are based on small numbers. PMID:23048059

Long-term variability of dust events in Iceland (1949-2011)

NASA Astrophysics Data System (ADS)

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.

2014-12-01

The long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and interpreted together with earlier results obtained from northeastern (NE) Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust observations. However, frequent volcanic eruptions, with the re-suspension of volcanic materials and dust haze, increased the number of dust events fourfold (135 dust days annually). The position of the Icelandic Low determined whether dust events occurred in the NE (16.4 dust days annually) or in the southern (S) part of Iceland (about 18 dust days annually). The decade with the most frequent dust days in S Iceland was the 1960s, but the 2000s in NE Iceland. A total of 32 severe dust storms (visibility < 500 m) were observed in Iceland with the highest frequency of events during the 2000s in S Iceland. The Arctic dust events (NE Iceland) were typically warm, occurring during summer/autumn (May-September) and during mild southwesterly winds, while the subarctic dust events (S Iceland) were mainly cold, occurring during winter/spring (March-May) and during strong northeasterly winds. About half of the dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between particulate matter (PM10) concentrations and visibility during dust observations at the stations Vík and Stórhöfði. This study shows that Iceland is among the dustiest areas of the world and that dust is emitted year-round.

The fishery for Iceland scallop (Chlamys islandica) in the Northeast Atlantic.

PubMed

Garcia, Elena Guijarro

2006-01-01

This review focuses on the history and management of the Iceland scallop fishery in Iceland, Greenland and Norway (including the Svalbard archipelago and the islands of Bjørnøya and Jan Mayen), with information on research into each stock. The start of the fishery in all these regions followed the discovery of virgin scallop beds made up of old, large specimens in very high densities. Despite the apparent similarity of original conditions, the fishery has followed very different trends in each region, with drastic declines in Iceland, Svalbard and Jan Mayen. The general biology of the Iceland scallop is summarised and compared with the biology of other North Atlantic species of pectinids. The Icelandic fishery dates from 1969. There was a steady decrease in catch from 1985, when >16,000 tonnes were caught. By 2004 the stock had declined to 35% of its average size during the period 1993-2000 and a zero quota was advised. This decline is thought to have resulted from overexploitation, combined with a protozoan infestation and increasing sea bottom temperature. Scallop dredging commenced in west Greenland in 1983. The stock is not very large, but fishing was driven by social factors. Catches ranged from 400 to 1,900 tonnes during the period 1988-1992 and from 1,200 to 2,600 tonnes since 1995. There are indications that each scallop bed is extensively dredged before the fleet moves on to new areas, but nevertheless catches have been rather stable over the past decade. The scallop stocks in Svalbard, Bjørnøya and Jan Mayen were depleted in three fishing seasons between 1985-1987, when up to 45,000 tonnes of scallops were dredged in a single season. Following a survey carried out in 1991, Bjørnøya was open to the fishery with a maximum quota of 2,000 tonnes, but the stock off Svalbard was found to be not large enough to sustain a fishery.

Iceland Volcano

Atmospheric Science Data Center

2013-04-23

article title:  Eyjafjallajökull, Iceland, Volcano Ash Cloud     View larger ... Europe and captured this image of the Eyjafjallajökull Volcano ash cloud as it continued to drift over the continent. Unlike other ...

Paleocene Wilcox cross-shelf channel-belt history and shelf-margin growth: Key to Gulf of Mexico sediment delivery

NASA Astrophysics Data System (ADS)

Zhang, Jinyu; Steel, Ronald; Ambrose, William

2017-12-01

Shelf margins prograde and aggrade by the incremental addition of deltaic sediments supplied from river channel belts and by stored shoreline sediment. This paper documents the shelf-edge trajectory and coeval channel belts for a segment of Paleocene Lower Wilcox Group in the northern Gulf of Mexico based on 400 wireline logs and 300 m of whole cores. By quantitatively analyzing these data and comparing them with global databases, we demonstrate how varying sediment supply impacted the Wilcox shelf-margin growth and deep-water sediment dispersal under greenhouse eustatic conditions. The coastal plain to marine topset and uppermost continental slope succession of the Lower Wilcox shelf-margin sediment prism is divided into eighteen high-frequency ( 300 ky duration) stratigraphic sequences, and further grouped into 5 sequence sets (labeled as A-E from bottom to top). Sequence Set A is dominantly muddy slope deposits. The shelf edge of Sequence Sets B and C prograded rapidly (> 10 km/Ma) and aggraded modestly (< 80 m/Ma). The coeval channel belts are relatively large (individually averaging 11-13 m thick) and amalgamated. The water discharge of Sequence Sets B and C rivers, estimated by channel-belt thickness, bedform type, and grain size, is 7000-29,000 m3/s, considered as large rivers when compared with modern river databases. In contrast, slow progradation (< 10 km/Ma) and rapid aggradation (> 80 m/Ma) characterizes Sequence Sets D and E, which is associated with smaller (9-10 m thick on average) and isolated channel belts. This stratigraphic trend is likely due to an upward decreasing sediment supply indicated by the shelf-edge progradation rate and channel size, as well as an upward increasing shelf accommodation indicated by the shelf-edge aggradation rate. The rapid shelf-edge progradation and large rivers in Sequence Sets B and C confirm earlier suggestions that it was the early phase of Lower Wilcox dispersal that brought the largest deep-water sediment

Climate variability and the Icelandic marine ecosystem

NASA Astrophysics Data System (ADS)

Astthorsson, Olafur S.; Gislason, Astthor; Jonsson, Steingrimur

2007-11-01

This paper describes the main features of the Icelandic marine ecosystem and its response to climate variations during the 20th century. The physical oceanographic character and faunal composition in the southern and western parts of the Icelandic marine ecosystem are different from those in the northern and the eastern areas. The former areas are more or less continuously bathed by warm and saline Atlantic water while the latter are more variable and influenced by Atlantic, Arctic and even Polar water masses to different degrees. Mean annual primary production is higher in the Atlantic water than in the more variable waters north and east of Iceland, and higher closer to land than farther offshore. Similarly, zooplankton production is generally higher in the Atlantic water than in the waters north and east of Iceland. The main spawning grounds of most of the exploited fish stocks are in the Atlantic water south of the country while nursery grounds are off the north coast. In the recent years the total catch of fish and invertebrates has been in the range of 1.6-2.4 million ton. Capelin ( Mallotus villosus) is the most important pelagic stock and cod ( Gadus morhua) is by far the most important demersal fish stock. Whales are an important component of the Icelandic marine ecosystem, and Icelandic waters are an important habitat for some of the largest seabird populations in the Northeast Atlantic. In the waters to the north and east of Iceland, available information suggests the existence of a simple bottom-up controlled food chain from phytoplankton through Calanus, capelin and to cod. Less is known about the structure of the more complex southern part of the ecosystem. The Icelandic marine ecosystem is highly sensitive to climate variations as demonstrated by abundance and distribution changes of many species during the warm period in the 1930s, the cold period in the late 1960s and warming observed during the recent years. Some of these are highlighted in the

Iceland’s Financial Crisis

DTIC Science & Technology

2008-11-20

distress. In particular, access to easy credit, a boom in domestic construction that fueled rapid economic growth, and a broad deregulation of...pressure on the value of the krona and worsened the trade deficit. As Iceland deregulated its commercial banks, those banks expanded to the United Kingdom...2007 valued at $9 billion. After Iceland deregulated its commercial banks, the banks expanded their operations abroad by acquiring subsidiaries in

Iceland: health system review.

PubMed

Sigurgeirsdóttir, Sigurbjörg; Waagfjörð, Jónína; Maresso, Anna

2014-01-01

This analysis of the Icelandic health system reviews the developments in its organization and governance, health financing, health care provision, health reforms and health system performance. Life expectancy at birth is high and Icelandic men and women enjoy longer life in good health than the average European. However, Icelanders are putting on weight, more than half of adult Icelanders were overweight or obese in 2004, and total consumption of alcohol has increased considerably since 1970. The health care system is a small, state centred, publicly funded system with universal coverage, and an integrated purchaser provider relationship in which the state as payer is also the owner of most organizations providing health care services. The country's centre of clinical excellence is the University Hospital, Landspitali, in the capital Reykjavik, which alone accounts for 70 percent of the total national budget for general hospital services. However, since 1990, the health system has become increasingly characterized by a mixed economy of care and service provision, in which the number and scope of private non profit and private for profit providers has increased. While Iceland's health outcomes are some of the best among OECD countries, the health care system faces challenges involving the financial sustainability of the current system in the context of an ageing population, new public health challenges, such as obesity, and the continued impact of the country's financial collapse in 2008. The most important challenge is to change the pattern of health care utilization to steer it away from the most expensive end of the health services spectrum towards more cost efficient and effective alternatives. To a large degree, this will involve renewed attempts to prioritize primary care as the first port of call for patients, and possibly to introduce a gatekeeping function for GPs in order to moderate the use of specialist services. World Health Organization 2014 (acting as

The First Sourcebook on Nordic Research in Mathematics Education: Norway, Sweden, Iceland, Denmark and Contributions from Finland.

ERIC Educational Resources Information Center

Sriraman, Bharath, Ed.; Bergsten, Christer, Ed.; Goodchild, Simon, Ed.; Palsdottir, Gudbjorg, Ed.; Sondergaard, Bettina Dahl, Ed.; Haapasalo, Lenni, Ed.

2010-01-01

The First Sourcebook on Nordic Research in Mathematics Education: Norway, Sweden, Iceland, Denmark and contributions from Finland provides the first comprehensive and unified treatment of historical and contemporary research trends in mathematics education in the Nordic world. The book is organized in sections co-ordinated by active researchers in…

[Icelanders' beliefs about medicines. Use of BMQ].

PubMed

Vilhelmsdottir, Hlif; Johannsson, Magnus

2017-01-01

To study beliefs held by the general public in Iceland about medicines. The Beliefs about Medicines Questionnaire was used to explore Icelanders' beliefs about medicines. A sample of 1500 Icelandic citizens, aged 18-75, obtained from the Social Science Research Insti-tute was given The Beliefs about Medicines Questionnaire. The response rate was 61.6%. Most Icelanders have positive beliefs about their medication as well as general trust. Those who suffer from chronic diseases are more positive towards medicines than others and less inclined to view them as excessively used and harmful. Higher level of education predicts more positive beliefs towards medication - and vice versa. Gender and age do not seem to affect such beliefs. Gaining a better understanding of people´s beliefs about medicines and what determines these beliefs can be of considerable value in the search for ways to improve therapy and adherence, espe-cially for those suffering from chronic diseases. Promoting education for the general public about medicines might result in less mis-understanding among patients and subsequently better grounded -beliefs and more adequate therapeutic adherence. Key words: beliefs, medicines, Icelanders, BMQ, survey. Correspondence: Hlif Vilhelmsdottir, hlif84@gmail.com.

Molecular epidemiology of HIV-1 in Iceland: Early introductions, transmission dynamics and recent outbreaks among injection drug users.

PubMed

Sallam, Malik; Esbjörnsson, Joakim; Baldvinsdóttir, Guðrún; Indriðason, Hlynur; Björnsdóttir, Thora Björg; Widell, Anders; Gottfreðsson, Magnús; Löve, Arthur; Medstrand, Patrik

2017-04-01

The molecular epidemiology of HIV-1 in Iceland has not been described so far. Detailed analyses of the dynamics of HIV-1 can give insights for prevention of virus spread. The objective of the current study was to characterize the genetic diversity and transmission dynamics of HIV-1 in Iceland. Partial HIV-1 pol (1020bp) sequences were generated from 230 Icelandic samples, representing 77% of all HIV-1 infected individuals reported in the country 1985-2012. Maximum likelihood phylogenies were reconstructed for subtype/CRF assignment and determination of transmission clusters. Timing and demographic growth patterns were determined in BEAST. HIV-1 infection in Iceland was dominated by subtype B (63%, n=145) followed by subtype C (10%, n=23), CRF01_AE (10%, n=22), sub-subtype A1 (7%, n=15) and CRF02_AG (7%, n=15). Trend analysis showed an increase in non-B subtypes/CRFs in Iceland over the study period (p=0.003). The highest proportion of phylogenetic clustering was found among injection drug users (IDUs; 89%), followed by heterosexuals (70%) and men who have sex with men (35%). The time to the most recent common ancestor of the oldest subtype B cluster dated back to 1978 (median estimate, 95% highest posterior density interval: 1974-1981) suggesting an early introduction of HIV-1 into Iceland. A previously reported increase in HIV-1 incidence among IDUs 2009-2011 was revealed to be due to two separate outbreaks. Our study showed that a variety of HIV-1 subtypes and CRFs were prevalent in Iceland 1985-2012, with subtype B being the dominant form both in terms of prevalence and domestic spread. The rapid increase of HIV-1 infections among IDUs following a major economic crisis in Iceland raises questions about casual associations between economic factors, drug use and public health. Copyright © 2017 Elsevier B.V. All rights reserved.

Iceland

NASA Image and Video Library

2017-12-08

On August 22, 2014 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured a true-color image of a sunny summer day in Iceland. While most of the winter snow has melted to reveal green vegetation, the rugged northern peaks retain a snow cap. Further south bright white marks the location of glaciers. Situated in the southeast is Vatnajökull – the largest glacier in Europe and the site of Iceland’s highest mountain, Hvannadalshnjúkur. On August 20, scientists from the Icelandic Met Office closed all roads into the north of Vatnajökull Glacier due to increase seismic activity from the Bardarbunga volcano which lies under the ice cap in this area. On August 23, a small eruption was detected in Bardarbunga and the airspace near the activity was closed as a precautionary measure. Further study of the data suggested that no eruption had in fact occurred and airspace was opened under a code orange alert. Seismic activity remained high. On August 29, an eruption occurred north of Vatnajökull Glacier when a fissure, close to 1 km in length, opened up, and emitted lava at a slow pace. The eruption was short-lived, but on August 31 an eruption was confirmed in the same remote, uninhabited area. The Icelandic Meteorological Office reported that as of September 11 that eruption continued unabated. There has been no significant explosive activity, but lava flow has been the primary feature. High concentrations of sulfuric gases from the volcanic activity accompany the eruption, and are the primary health concern. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team 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

Seafloor Spreading Reorganization South of Iceland

NASA Astrophysics Data System (ADS)

Hey, R. N.; Martinez, F.; Benediktsdottir, A.; Hoskuldsson, A.

2011-12-01

There is a major ongoing diachronous reorganization of North Atlantic seafloor spreading occurring at present south of Iceland, from an orthogonal ridge/transform geometry to the present oblique spreading geometry without transform faults on the Reykjanes Ridge. This reorganization is presently interpreted as a thermal phenomenon, with a pulse of warmer mantle expanding away from the Iceland plume causing a progressive change in subaxial mantle rheology from brittle to ductile, so that transform faults can no longer be maintained. Given that this is certainly the most obvious and arguably the type-example of active plate boundary reorganization, it is somewhat surprising that a thermal mechanism has near universal acceptance here whereas most if not all other seafloor spreading reorganizations are equally universally thought to result from the tectonic rift propagation mechanism. This suggests the possibility that either the thermal model might be wrong here, or that the propagating rift (PR) model might be wrong elsewhere. The reason the PR alternative was ignored here was that the younger seafloor record flanking the Reykjanes Ridge consisting of V-shaped ridges, troughs & scarps (VSRs) enclosed by the reorganization wake seemed to prove that there had been no rift propagation. It had long been thought that these VSRs were symmetric about the spreading axis, & if this conventional wisdom (that led directly to the pulsing Iceland plume model) were true, rift propagation, which must produce asymmetry, could not have occurred. However, our expedition collected marine geophysical data that showed that the VSRs actually have an asymmetric geometry consistent with rift propagation, not with previous pulsing plume models, & thus they can no longer be considered convincing proof of a pulsing Iceland plume. Although we had previously noted that plume pulses might drive the propagators away from Iceland, a significant new result (Benediktsdóttir et al., 2011) is that

Plague and landscape resilience in premodern Iceland.

PubMed

Streeter, Richard; Dugmore, Andrew J; Vésteinsson, Orri

2012-03-06

In debates on societal collapse, Iceland occupies a position of precarious survival, defined by not becoming extinct, like Norse Greenland, but having endured, sometimes by the narrowest of margins. Classic decline narratives for late medieval to early modern Iceland stress compounding adversities, where climate, trade, political domination, unsustainable practices, and environmental degradation conspire with epidemics and volcanism to depress the Icelanders and turn the once-proud Vikings and Saga writers into one of Europe's poorest nations. A mainstay of this narrative is the impact of incidental setbacks such as plague and volcanism, which are seen to have compounded and exacerbated underlying structural problems. This research shows that this view is not correct. We present a study of landscape change that uses 15 precisely dated tephra layers spanning the whole 1,200-y period of human settlement in Iceland. These tephras have provided 2,625 horizons of known age within 200 stratigraphic sections to form a high-resolution spatial and temporal record of change. This finding shows short-term (50 y) declines in geomorphological activity after two major plagues in A.D. 15th century, variations that probably mirrored variations in the population. In the longer term, the geomorphological impact of climate changes from the 14th century on is delayed, and landscapes (as well as Icelandic society) exhibit resilience over decade to century timescales. This finding is not a simple consequence of depopulation but a reflection of how Icelandic society responded with a scaling back of their economy, conservation of core functionality, and entrenchment of the established order.

Continental crust beneath southeast Iceland

PubMed Central

Torsvik, Trond H.; Amundsen, Hans E. F.; Trønnes, Reidar G.; Doubrovine, Pavel V.; Gaina, Carmen; Kusznir, Nick J.; Steinberger, Bernhard; Corfu, Fernando; Ashwal, Lewis D.; Griffin, William L.; Werner, Stephanie C.; Jamtveit, Bjørn

2015-01-01

The magmatic activity (0–16 Ma) in Iceland is linked to a deep mantle plume that has been active for the past 62 My. Icelandic and northeast Atlantic basalts contain variable proportions of two enriched components, interpreted as recycled oceanic crust supplied by the plume, and subcontinental lithospheric mantle derived from the nearby continental margins. A restricted area in southeast Iceland—and especially the Öræfajökull volcano—is characterized by a unique enriched-mantle component (EM2-like) with elevated 87Sr/86Sr and 207Pb/204Pb. Here, we demonstrate through modeling of Sr–Nd–Pb abundances and isotope ratios that the primitive Öræfajökull melts could have assimilated 2–6% of underlying continental crust before differentiating to more evolved melts. From inversion of gravity anomaly data (crustal thickness), analysis of regional magnetic data, and plate reconstructions, we propose that continental crust beneath southeast Iceland is part of ∼350-km-long and 70-km-wide extension of the Jan Mayen Microcontinent (JMM). The extended JMM was marginal to East Greenland but detached in the Early Eocene (between 52 and 47 Mya); by the Oligocene (27 Mya), all parts of the JMM permanently became part of the Eurasian plate following a westward ridge jump in the direction of the Iceland plume. PMID:25825769

Icelandic: Linguistic Maintenance or Change? The Role of English. Occasional Paper.

ERIC Educational Resources Information Center

Hilmarsson-Dunn, Amanda

The Icelandic language has a long and stable history, and Old Icelandic is still accessible to modern day Icelanders. This is despite being ruled from Denmark, with influence by the Danish language, for about 500 years. Icelandic may now be under a more serious threat from the onslaught of English. This paper evaluates the linguistic situation in…

Public opinion on childhood immunisations in Iceland.

PubMed

Óskarsson, Ýmir; Guðnason, Þórólfur; Jónsdóttir, Guðbjörg A; Kristinsson, Karl G; Briem, Haraldur; Haraldsson, Ásgeir

2015-12-16

In recent years, vaccine preventable diseases such as measles and pertussis have been re-emerging in Western countries, maybe because of decreasing participation in childhood vaccination programs in some countries. There is clear evidence for vaccine efficacy and the risk of adverse effects is low. This needs to be communicated to the general public. The aim of the study was to evaluate the public opinion on childhood vaccinations in Iceland. An internet based study was used to evaluate the opinion on childhood immunisations in Iceland. The cohort was divided in three groups: (a) general public (b) employees of the University Hospital Iceland and (c) employees (teachers and staff) of the University of Iceland. The cohorts could be stratified according to age, gender, education, household income, parenthood and residency. Responses were received from 5584 individuals (53% response rate). When asked about childhood vaccinations in the first and second year of life, approximately 95% of participants were "positive" or "very positive", approximately 1% were "negative" or "very negative". When participants were asked whether they would have their child immunized according to the Icelandic childhood vaccination schedule, 96% were "positive" or "very positive", 1.2% were "negative" or "very negative". Similarly, 92% trust Icelandic Health authorities to decide on childhood vaccination schedule, 2.3% did not. In total, 9.3% "rather" or "strongly" agreed to the statement "I fear that vaccinations can cause severe adverse effects", 17.5% were undecided and 66.9% "disagreed" or "strongly disagreed". Individuals with higher education were more likely to disagree with this statement (OR=1.45, CI95=1.29-1.64, p<0.001) as did males (OR=1.22, CI95=1.087-1.379, p=0.001). This study shows a very positive attitude towards vaccinations raising expectations for an ongoing success in preventing preventable communicable diseases in childhood in Iceland. Copyright © 2015 Elsevier Ltd

Evaluating nature and wilderness in Iceland

Treesearch

Thora Ellen Thorhallsdottir

2002-01-01

Iceland is sparsely populated with towns and farms mostly restricted to coastal lowlands. The country’s ca 50,000 km2 (19,000 mi2) interior is an uninhabited highland with isolated mountains and large glaciers. At present, only a small part of Iceland’s rich geothermal and hydroelectric resources have been harnessed, but if political commitments to largescale...

History of the incipient Icelandic plume: Observations from ancient buried landscapes

NASA Astrophysics Data System (ADS)

Stucky de Quay, Gaia; Roberts, Gareth G.; Watson, Jonathan S.; Jackson, Christopher A.-L.

2017-04-01

Ancient buried terrestrial landscapes contain records of vertical motions which can be used to probe histories of geodynamical processes. In the North Atlantic Ocean, sedimentary basins contain excellent evidence that the continental shelf experienced staged subaerial exposure. For example, now buried landscapes were uplifted, rapidly eroded, and drowned close to the Paleocene-Eocene boundary. We use commercial wells and three-dimensional seismic data to reconstruct a 57-55 Ma landscape now buried 1.5 km beneath the seabed in the Bressay area of the northern North Sea. Geochemical analyses of organic matter from core samples intersecting the erosional landscape indicate the presence of angiosperm (flowering plant) debris. Combined with the presence of coarse clastic material, mapped beach ridges, and dendritic drainage patterns, these observations indicate that this landscape was of terrestrial origin. Longitudinal profiles of ancient rivers were extracted and inverted for an uplift rate history. The best-fitting uplift rate history has three phases and total cumulative uplift of 350 m. Biostratigraphic data from surrounding marine stratigraphy indicate that this landscape formed within 1-1.5 Ma. This uplift history is similar to that of a slightly older buried landscape in the Faeroe-Shetland basin 400 km to the west. These records of vertical motion can explained by pulses of anomalously hot asthenosphere spreading out from the incipient Icelandic plume. Using simple isostatic calculations we estimate that the maximum thermal anomaly beneath Bressay was 50˚. Our observations suggest that a thermal anomaly departed the Icelandic plume as early as 58.5 Ma and had highest average temperatures at 55.6 Ma.

Modelling the effects of ice-sheet activity on CO2 outgassing by Icelandic volcanoes

NASA Astrophysics Data System (ADS)

Armitage, J. J.; Ferguson, D.; Petersen, K. D.; Creyts, T. T.

2017-12-01

Glacial cycles may play a significant role in mediating the flux of magmatic CO2 between the Earth's mantle and atmosphere. In Iceland, it is thought that late-Pleistocene deglaciation led to a significant volcanic pulse, evidenced by increased post-glacial lava volumes and changes in melt chemistry consistent with depressurization. Investigating the extent to which glacial activity may have affected volcanic CO2 emissions from Iceland, and crucially over what timescale, requires detailed knowledge of how the magma system responded to the growth and collapse of the ice-sheet before and after the LGM. To investigate this, we coupled a model of magma generation and transport with a history of ice-sheet activity. Our results show that the emplacement and removal of the LGM ice-sheet likely led to two significant pulses of magmatic CO2. The first, and most significant of these, is associated with ice-sheet growth and occurs as the magma system recovers from glacial loading. This recovery happens from the base of the melting region upwards, producing a pulse of CO2 rich magma that is predicted to reach the surface around 20 ka after the loading event, close in time to the LGM. The second peak in CO2 output occurs abruptly following deglaciation as a consequence of increased rates of melt generation and transport in the shallow mantle. Although these post-glacial melts are relatively depleted in CO2, the increase in magma flux leads to a short-lived period of elevated CO2 emissions. Our results therefore suggest a negative feedback, whereby ice-sheet growth produces a delayed pulse of magmatic CO2, which, in addition to increased geothermal heat flux, may contribute towards driving deglaciation, which itself then causes further magmatism and CO2 outgassing. This model is consistent with the seismic structure of the asthenosphere below Iceland, and the established compositional and volumetric trends for sub- and post-glacial volcanism in Iceland. These trends show that

Life Interpretation and Religion among Icelandic Teenagers

ERIC Educational Resources Information Center

Gunnarsson, Gunnar J.

2009-01-01

Does religion play any specific part in Icelandic teenagers' life interpretation? This paper examines Icelandic teenagers' talk about religion and presents some of the findings in interviews with teenagers in a qualitative research project. The focus is especially on how three individuals express themselves about the influence of religion on their…

Education in Iceland: Its Rise and Growth.

ERIC Educational Resources Information Center

Josephson, Bragi S.

This document is an English-language abstract (approximately 1,500 words) of a Doctorate of Education dissertation on the development of education in Iceland since 874 A.D. Special attention has been given to social, political, and economic issues influencing Icelandic education. The procedure consisted of reviewing the literature, interviewing…

Man against volcano: The eruption on Heimaey, Vestmann Islands, Iceland

USGS Publications Warehouse

Williams, R.S.; Moore, J.G.

1976-01-01

The U.S. Geological Survey carries out scientific studies in the geological, hydrological, and cartographic sciences generally within the 50 states, but also in cooperation with scientific organizations in many foreign countries for the investigation of unusual earth science phenomena throughout the world. The following material discusses the impact of the 1973 volcanic eruption of Eldfell on the fishing port of Vestmannaeyjar on the island of Heimaey, Iceland. Before the eruption was over, approximately one-third of the town of Vestmannaeyjar had been obliterated but, more importantly, the potential damage had been reduced markedly by the spraying of seawater onto the advancing lava flows, causing them to be slowed, stopped, or diverted from the undamaged portion of the town. The Survey's interest and involvement in the Heimaey eruption in Iceland was occasioned by the possibility that the procedures used to control the course of the flowing lava and to reduce the damage in a modern town may some day be needed in Hawaii and possibly even in the continental United States. This publication is based on the observations of two USGS geologists, Richard S. Williams, Jr. and James G. Moore, as well as on information from the Icelandic Ministry for Foreign Affairs, Icelandic scientists' reports through the Center for Short-Lived Phenomena, and other published scientific reports. A number of Icelandic scientists studied the scientific aspects of the eruption and the engineering aspects of the control of lava flows, in particular, Professors Thorbjb'rn Sigurgeirsson and Sigurdur Thorarinsson of the University of Iceland Science Institute. Also, Icelandic governmental officials provided logistical and other support, in particular, Mr. Steingnmur Hermannsson, Director, Icelandic National Research Council and Professor Magnus Magnusson, Director, University of Iceland Science Institute.

Examining Teaching Practices in Design and Craft Education in Iceland

ERIC Educational Resources Information Center

Thorsteinsson, Gisli; Olafsson, Brynjar

2017-01-01

This article reports a survey which aimed to examine the present situation in Design and Craft Education (D&C) in Iceland in terms of teachers' general standing and their teaching inside the Icelandic elementary schools. A questionnaire was sent to 170 D&C teachers in Icelandic elementary schools. The questionnaire was completed by 101…

Aeolian Environments of Iceland

NASA Astrophysics Data System (ADS)

Arnalds, Olafur; Olafsson, Haraldur; Dagsson Waldhauserová, Pavla

2017-04-01

Iceland has the largest area of volcaniclastic sandy desert on Earth or 22,000 km2. The sand has been mostly produced by glacio-fluvial processes, leaving behind fine-grained unstable sediments which are later re-distributed by repeated aeolian events. Volcanic eruptions add to this pool of unstable sediments, often from subglacial eruptions. Icelandic desert surfaces are divided into sand fields, sandy lavas and sandy lag gravel, each with separate aeolian surface characteristics such as threshold velocities. Storms are frequent due to Iceland's location on the North Atlantic Storm track. Dry winds occur on the leeward sides of mountains and glaciers, in spite of the high moisture content of the Atlantic cyclones. Surface winds often move hundreds to more than 1000 kg m-1 per annum, and more than 10,000 kg m-1 have been measured in a single storm. Desertification occurs when aeolian processes push sand fronts and have thus destroyed many previously fully vegetated ecosystems since the time of the settlement of Iceland in the late ninth century. There are about 135 dust events per annum, ranging from minor storms to >300,000 t of dust emitted in single storms. Dust can be generated from all the major sandy areas of Iceland; however the amount of finer particles that become dust varies with the surfaces. There are areas that produce more dust by far compared to the general sandy deserts; they have therefore been termed "dust plume areas" or "dust hot-spots". They are characterized by repeated charging of fine sediments with a relatively high proportion of finer (silty) materials which, upon repeated wind erosion become sorted downwind from the sources with loss of silt (dust) and an increasing saltation component (sand). Dust production is on the order of 30-40 million tons annually, some travelling over 1000 km and deposited on land and sea. Dust deposited on deserts tends to be re-suspended during subsequent storms. High PM10 concentrations occur during major dust

[Effects of volcanic eruptions on human health in Iceland. Review].

PubMed

Gudmundsson, Gunnar; Larsen, Guðrun

2016-01-01

Volcanic eruptions are common in Iceland and have caused health problems ever since the settlement of Iceland. Here we describe volcanic activity and the effects of volcanic gases and ash on human health in Iceland. Volcanic gases expelled during eruptions can be highly toxic for humans if their concentrations are high, irritating the mucus membranes of the eyes and upper respiratory tract at lower concentrations. They can also be very irritating to the skin. Volcanic ash is also irritating for the mucus membranes of the eyes and upper respiratory tract. The smalles particles of volcanic ash can reach the alveoli of the lungs. Described are four examples of volcanic eruptions that have affected the health of Icelanders. The eruption of Laki volcanic fissure in 1783-1784 is the volcanic eruption that has caused the highest mortality and had the greatest effects on the well-being of Icelanders. Despite multiple volcanic eruptions during the last decades in Iceland mortality has been low and effects on human health have been limited, although studies on longterm effects are lacking. Studies on the effects of the Eyjafjallajökul eruption in 2010 on human health showed increased physical and mental symptoms, especially in those having respiratory disorders. The Directorate of Health in Iceland and other services have responded promptly to recurrent volcanic eruptions over the last few years and given detailed instructions on how to minimize the effects on the public health. Key words: volcanic eruptions, Iceland, volcanic ash, volcanic gases, health effects, mortality. Correspondence: Gunnar Guðmundsson, ggudmund@landspitali.is.

Non-Linear Response to Holocene Insolation Forcing Recorded by High-Resolution Lake Sediment Records Across Iceland

NASA Astrophysics Data System (ADS)

Geirsdottir, A.; Miller, G. H.; Axford, Y.

2009-12-01

Many Icelandic lakes have sedimentation rates in excess of 1 m ka-1 throughout the Holocene. Such high rates offer the potential for decadally resolved (or better) records of environmental change at this sensitive North Atlantic site. Abundant well-defined tephra provide a secure geochronology. The fidelity of the common climate proxies biogenic silica (BSi) and total organic carbon (TOC), was tested by comparing these proxies in three lakes with very different catchment characteristics. Hestvatn (HST, 60 m deep) in southern Iceland receives overflow from a large river originating in the glaciated highlands of central Iceland, whereas the nearby lake Vestra Gislholtsvatn (VGHV, 15 m deep) has a small, low elevation catchment without glaciers. Haukadalsvatn (HAK, 42 m deep), in northwestern Iceland, has a large, high relief catchment. The BSi record from HAK has been shown to reflect April-May temperatures, with BSi highest when spring temperatures are at their maximum. The first- and second-order trends in BSi are similar in all three lakes for most of the Holocene. This supports the contention that BSi reflects primary productivity, and is less influenced by changes in sedimentation rate. In all three lakes, BSi reaches a maximum value shortly after 8 ka, and then declines gradually toward present, reflecting a relatively late Holocene thermal maximum, potentially due to the influence of meltwater from the lingering Laurentide Ice Sheet. A steady reduction in summer insolation determines this first-order trend towards lower BSi through the middle and late Holocene. Large, abrupt departures from the overall decrease in BSi characterize all three records after 8 ka. Following each rapid BSi decrease, BSi usually exhibits a step-function change, re-equilibrating at a lower BSi value. Some of the strongest departures (ca. 6 ka, 4 to 4.5 ka and ca. 3 ka) may be related to Icelandic volcanism, but the lack of a full recovery to pre-existing values after the eruptions

The Relevance of English Language Instruction in a Changing Linguistic Environment in Iceland: The L2 Self of Young Icelanders

ERIC Educational Resources Information Center

Jeeves, Anna

2014-01-01

In this study perceptions of post-compulsory school studies in Iceland were investigated through semi-structured interviews. While colloquial English suffices for entertainment, hobbies and Internet use in Iceland, a high level of proficiency is required for employment and tertiary study. School learners and young people in tertiary study and…

The Neogene of the Iceland Sea - Paleoenvironmental reconstructions using marine palynomorphs

NASA Astrophysics Data System (ADS)

Schreck, M.; Matthiessen, J.; Stein, R.

2012-04-01

ODP Hole 907A was drilled in the Iceland Sea as the mid-point of a paleoenvironmental transect across the Norwegian-Greenland Sea in order to investigate the response of the Arctic gateway region to the long-term global cooling that occurred after the Miocene Climate Optimum. However, owing to a generally low carbonate deposition/preservation and scarcity of calcareous microfossils in Neogene sediments of the Nordic Seas, the application of these traditionally used microfossils and deduced δ18O and Mg/Ca temperature proxies is strongly hampered. Hence, most previous studies have focussed on reconstructing the paleoceanographic and paleoclimatic history since the onset of large-scale Northern Hemisphere glaciations. On that account, the Miocene and parts of the Pliocene have been largely ignored and the Neogene paleoenvironmental history of the Nordic Seas still remains enigmatic. To bypass the absence of biogenic carbonates, organic-walled microfossils (e.g. dinoflagellate cysts, prasinophyte algae and acritarchs) are required for detailed paleoenvironmental reconstructions on pre-Quaternary timescales since they are continuously present and show relatively high abundance and diversity in the high northern latitudes hemipelagic sediments. ODP Hole 907A in the Iceland Sea, located close to the growing ice sheets, experienced the effects of sea-ice cover, migrating wind fronts and ocean currents, thus being a sensitive area with respect to global climate. In this context, Neogene climate deterioration and associated reorganisation of global ocean circulation must have led to alterations in the palynomorph association and may have affected turnover in species composition. Here we present a comparatively high-resolution palynomorph record from the almost continuous Middle Miocene to Late Pliocene sediment sequence of ODP Hole 907A in the Iceland Sea. Its pristine paleomagnetic record provides the unique opportunity for detailed investigations on how palynomorph

Icelandic Analogs for Volcanic and Fluvial Processes on Mars

NASA Astrophysics Data System (ADS)

McEwen, A.; Burr, D.; Hardardottir, J.; Hoskuldsson, A.; Keszthelyi, L.; Lanagan, P.; Snorrason, A.; Thordarson, T.

2001-12-01

Iceland has proven to be an excellent location to study a wide range of Martian geologic analogs. Among these are basaltic volcanism and aqueous flooding--key geologic processes that have shaped the Martian surface and that remain active in Iceland. On both Mars and Iceland, volcanic units are interfingered in space and time with fluvial units. Well-preserved flood lavas in SE Elysium Planitia, Amazonis Planitia, and portions of the Tharsis rise are dominated by a distinctive morphology of plates and ridges, very similar to the "apalhraun" or "rubbly pahoehoe" of Iceland (Keszthelyi and Thordarson, 2000, GSA Abstract 52593). On both Iceland and Mars there are marginal regions of undisrupted inflated pahoehoe, small rootless cones, and long parallel structures in the wake of topographic obstacles. The Icelandic paleoflood channels of Jokulsa a Fjollum, extending from the Vatnajokull ice cap to the north coast, have eroded basaltic plains and provide many insights into morphologies seen on Mars. The manner in which different types of lava erode in a catastrophic flood is well illustrated and sometimes surprising. For example, there are channel floors where the crusts of inflated lavas have been completely stripped off by the floodwater, but then suddenly transitions upstream into a stretch with almost no erosion--even the cm-scale pahoehoe ropes are intact. This implies that significant aqueous floods could have occurred over some well-preserved lava flows on Mars. A streamlined "island" or mesa extending downstream from the volcanic crater Hrossaborg in Iceland appears to be mixture of remobilized older glacial deposits and a debris flow deposit. The debris flow apparently formed by collapse of the western outer crater slopes into the active floodwaters, diverting the flow northward; this process may have occurred on Mars at some of the impact craters eroded by outflow channels.

A New Look at Spreading in Iceland: Propagating Rifts, Migrating Transform Faults, and Microplate Tectonics

NASA Astrophysics Data System (ADS)

Karson, J.; Horst, A. J.; Nanfito, A.

2011-12-01

Iceland has long been used as an analog for studies of seafloor spreading. Despite its thick (~25 km) oceanic crust and subaerial lavas, many features associated with accretion along mid-ocean ridge spreading centers, and the processes that generate them, are well represented in the actively spreading Neovolcanic Zone and deeply glaciated Tertiary crust that flanks it. Integrated results of structural and geodetic studies show that the plate boundary zone on Iceland is a complex array of linked structures bounding major crustal blocks or microplates, similar to oceanic microplates. Major rift zones propagate N and S from the hotspot centered beneath the Vatnajökull icecap in SE central Iceland. The southern propagator has extended southward beyond the South Iceland Seismic Zone transform fault to the Westman Islands, resulting in abandonment of the Eastern Rift Zone. Continued propagation may cause abandonment of the Reykjanes Ridge. The northern propagator is linked to the southern end of the receding Kolbeinsey Ridge to the north. The NNW-trending Kerlingar Pseudo-fault bounds the propagator system to the E. The Tjörnes Transform Fault links the propagator tip to the Kolbeinsey Ridge and appears to be migrating northward in incremental steps, leaving a swath of deformed crustal blocks in its wake. Block rotations, concentrated mainly to the west of the propagators, are clockwise to the N of the hotspot and counter-clockwise to the S, possibly resulting in a component of NS divergence across EW-oriented rift zones. These rotations may help accommodate adjustments of the plate boundary zone to the relative movements of the N American and Eurasian plates. The rotated crustal blocks are composed of highly anisotropic crust with rift-parallel internal fabric generated by spreading processes. Block rotations result in reactivation of spreading-related faults as major rift-parallel, strike-slip faults. Structural details found in Iceland can help provide information

Iceland as a Model for Chemical Alteration on Mars

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Schiffman, P.; Murad, E.; Southard, R.; DeVincenzi, Donald L. (Technical Monitor)

2001-01-01

Subglacial volcanic activity on Iceland has led to the formation of a variety of silicate and iron oxide-rich alteration products that may serve as a model for chemical alteration on Mars. Multiple palagonitic tuffs, altered pillow lavas, hydrothermal springs and alteration at glacial run-off streams were observed during a recent field trip in Iceland. Formation of alteration products and ferrihydrite in similar environments on Mars may have contributed to the ferric oxide-rich surface material there. The spectral and chemical properties of Icelandic alteration products and ferrihydrites are presented here.

[Infection risks associated with importation of fresh food in Iceland].

PubMed

Kristinsson, Karl G; Georgsson, Franklín

2015-06-01

Access to safe food is a privilege for people living in Iceland. Rapid increase in antimicrobial resistance, related to factory farming and antimicrobial use in agriculture, is a major threat to public health. Increasing food trade between countries and continents facilitates global spread of pathogens and resistance. Icelandic agriculture has benefitted from its isolation and small size. After interventions to reduce the prevalence of Campylobacter and Salmonella at poultry farms, the incidence of human campylobacteriolsis is 17-43/100.000, of which about half is domestically acquired and Salmonella infections 10-15/100.000 mainly acquired abroad. Since Enterohaemorrhagic E. coli (EHEC) has not been detected in domestic cattle, the low incidence of infections is not surprising (0-0.6/100.000/year). A recent outbreak due to a multiresistant EHEC strain was traced to imported lettuce. Antimicrobial use in Icelandic agriculture is among the lowest in Europe and domestic infections caused by Salmonella and Campylobacter are rarely caused by resistant strains. Carbapenemase producing Enterobacteriaceae have not been found in Iceland. Low use of antimicrobials in Icelandic agriculture and actions to limit the spread of Campylobacter and Salmonella have been successful. The public should be informed of the importance of the origin of food and that Icelandic food products are among the safest.

Recent saltmarsh foraminiferal assemblages from Iceland

NASA Astrophysics Data System (ADS)

Lübbers, Julia; Schönfeld, Joachim

2018-01-01

This study reports for the first time boreal to subarctic intertidal foraminiferal assemblages from saltmarshes at Borgarnes and Faskrudsfjördur on Iceland. The composition of living and dead foraminiferal assemblages was investigated along transects from the tidal flat to the highest reach of halophytic plants. The foraminiferal assemblages from Borgarnes showed 18 species in the total foraminiferal assemblage of which only 7 species were recorded in the living fauna. The assemblages were dominated by agglutinated taxa, whereas 3 calcareous species were recorded, of which only Haynesina orbicularis was found in the living fauna. The distribution limit of calcifying species corresponds to the lower boundary of the lower saltmarsh vegetation zone. Furthermore, calcareous tests showed many features of dissolution, which is an indication of a carbonate corrosive environment. The species forming the dead assemblages were mainly derived from the ambient intertidal areas and were displaced by tidal currents into the saltmarsh. The foraminiferal assemblages from Faskrudsfjördur showed two species, of which only one species was recorded in the living fauna. The assemblage was dominated by the agglutinated foraminifer Trochaminita irregularis. The foraminiferal species recorded on Iceland were the same as commonly found elsewhere in Europa. Since no species was found which is endemic to North America, Iceland is considered part of the European bio province. The foraminiferal could have been immigrated to Iceland from Europe through warm water currents, migratory birds or marine traffic since the last Ice Age.

Re-Thinking Sustainable Education Systems in Iceland: The Net-University Project

ERIC Educational Resources Information Center

Rennie, Frank; Johannesdottir, Sigurbjorg

2011-01-01

The recent economic crisis in Iceland has raised issues of the sustainability of Icelandic higher education to new levels of importance. A key strategy in relation to this economic crisis is to consider the merger of the four public universities in Iceland and to introduce a much higher engagement with online and open delivery methods of higher…

Iceland's Grímsvötn volcano erupts

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-05-01

About 13 months after Iceland's Eyjafjallajökull volcano began erupting on 14 April 2010, which led to extensive air traffic closures over Europe, Grímsvötn volcano in southeastern took its turn. Iceland's most active volcano, which last erupted in 2004 and lies largely beneath the Vatnajökull ice cap, began its eruption activity on 21 May, with the ash plume initially reaching about 20 kilometers in altitude, according to the Icelandic Meteorological Office. Volcanic ash from Grímsvötn has cancelled hundreds of airplane flights and prompted U.S. president Barack Obama to cut short his visit to Ireland. As Eos went to press, activity at the volcano was beginning to subside.

Icelandic for Adult Foreigners: Effects of Imposing an Icelandic Language Test

ERIC Educational Resources Information Center

Innes, Pamela; Skaptadóttir, Unnur Dís

2017-01-01

Legislation linking language course attendance and passage of a language test for residence visas and citizenship, respectively, was enacted in Iceland in the early 2000s. Curricular guidelines and the language test were developed as a result. Research in other countries suggests such structures cause teachers to create "de facto"…

Extratropical Cyclones near Iceland

NASA Image and Video Library

2010-04-22

A cyclone is a low-pressure area of winds that spiral inwards. Although tropical storms most often come to mind, these spiraling storms can also form at mid- and high latitudes. Two such cyclones formed in tandem in November 2006. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA’s Terra satellite took this picture on November 20. This image shows the cyclones south of Iceland. Scotland appears in the lower right. The larger and perhaps stronger cyclone appears in the east, close to Scotland. Cyclones at high and mid-latitudes are actually fairly common, and they drive much of the Earth’s weather. In the Northern Hemisphere, cyclones move in a counter-clockwise direction, and both of the spiraling storms in this image curl upwards toward the northeast then the west. The eastern storm is fed by thick clouds from the north that swoop down toward the storm in a giant “V” shape on either side of Iceland. Skies over Iceland are relatively clear, allowing some of the island to show through. South of the storms, more diffuse cloud cover swirls toward the southeast. Credit: NASA NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Mapping of magnetic chrons: paleomagnetic polarity map of East Iceland, 0-13 Myr

NASA Astrophysics Data System (ADS)

Helgason, Johann

2016-04-01

Through data on palaeomagnetism, stratigraphy and radiometric age dating an immense database on magnetic chrons has been established for the lava succession in Iceland (e.g. Kristjánsson, 2008). Correlation of magnetic chrons with the geomagnetic time scale provides a reasonable age estimate for vast stratigraphic sequences. The basalt lava succession in Iceland has a thickness of tens of kilometers. The magnetostratigraphic data offer, through the help of paleomagnetism and radiometric dating, a detailed timing of events in the evolution of the Iceland mantle plume region. Yet a magnetic polarity map for Iceland has been lacking but during the last 50 years, comprehensive stratigraphic mapping has paved the way for a magnetic polarity map in various parts of Iceland. Here, such a map is presented for a segment of East Iceland, i.e. for lavas ranging in age from 0 to 13 M yr. The map is a compilation based on various studies into the cliff section and stratigraphic work performed by numerous research initiatives, both in relation to hydroelectric research as well as academic projects. References: Kristjánsson, L., 2008. Paleomagnetic research on Icelandic lava flows. Jökull, 58, 101-116. Helgason, J., Duncan, R.A., Franzson, H., Guðmundsson, Á., and M. Riishuus., 2015. Magnetic polarity map of Akrafjall and Skarðsheiði and new 40Ar-39Ar age dating from West Iceland., Presentation at the spring conference of the Icelandic Geological Society, held on March 13th 2015 at the University of Iceland.

Magmatic densities control erupted volumes in Icelandic volcanic systems

NASA Astrophysics Data System (ADS)

Hartley, Margaret; Maclennan, John

2018-04-01

Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland's Northern Volcanic Zone (NVZ). By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has been near-impossible when dealing with submarine samples dredged from mid-ocean ridges. We find a strong correlation between magmatic density and observed erupted volumes on the NVZ. Over 85% of the total volume of erupted material lies close to a density and viscosity minimum that corresponds to the composition of basalts at the arrival of plagioclase on the liquidus. These magmas are buoyant with respect to the Icelandic upper crust. However, a number of small-volume eruptions with densities greater than typical Icelandic upper crust are also found in Iceland's neovolcanic zones. We use a simple numerical model to demonstrate that the eruption of magmas with higher densities and viscosities is facilitated by the generation of overpressure in magma chambers in the lower crust and uppermost mantle. This conclusion is in agreement with petrological constraints on the depths of crystallisation under Iceland.

Miocene stratigraphy and structure of Sabine Pass, West Cameron, and East Cameron outer continental shelf areas, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, S.Y.; Watkins, J.S.

Mapping of Miocene stratigraphy and structure of the Sabine Pass, West Cameron, and East Cameron areas of the western Louisiana outer continental shelf - based on over 1300 mi of seismic data on a 4-mi grid, paleotops from 60 wells, and logs from 35 wells - resulted in time-structure and isochron maps at six intervals from the upper Pliocene to lower Miocene. The most pronounced structural features are the fault systems, which trend east-northeast to east along the Miocene stratigraphic trend. Isolated normal faults with small displacements characterize the inner inner shelf, whereas interconnected faults with greater displacements characterize themore » outer inner shelf. The inner inner shelf faults exhibit little growth, but expansion across the interconnected outer inner shelf fault ranges up to 1 sec two-way traveltime. The interconnected faults belong to two structurally independent fault families. The innermost shelf faults appear to root in the sediment column. A third set of faults located in the Sabine Pass area trends north-south. This fault set is thought to be related to basement movement and/or basement structure. Very little salt is evident in the area. A single diapir is located in West Cameron Block 110 and vicinity. There is little evidence of deep salt. Overall sediment thickness probably exceeds 20,000 ft, with the middle Miocene accounting for 8000 ft.« less

Explaining Gender Inequality in Iceland: What Makes the Difference?

ERIC Educational Resources Information Center

Heijstra, Thamar M.; O'Connor, Pat; Rafnsdóttir, Gudbjörg Linda

2013-01-01

This article examines the explanations offered by men and women, at different academic ranks, for the scarcity of women in full professorial positions in Icelandic universities. Data derive from interviews and a survey involving the total Icelandic academic population. We test three hypotheses: Firstly, academics will not see family…

Drying of seaweeds by geothermal heat in Iceland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hallsson, S.V.

For over a thousand years seaweeds have been sundered in Iceland for various uses, but geothermal heat was utilized for the first time for drying of seaweed in Hveragerdi 1939. During the sixties various experiments were carried on the drying of several types of seaweeds, grass, capeline and mussell in various sizes and types of experimental through-circulation dryers. On the bases of these experiments, a 5-belt through-circulation dryer was selected for the drying of seaweeds and possibly the mentioned marine and agricultural products in the commercial drying station built at Teykholar, W-Iceland, where seaweed meal has been produced since 1975.more » Results of drying experiments are compared with drying parameters in the commercial drying station at Teykholar, and the available data on drying of seaweeds using geothermal energy is summarized and compared with data from Scotland and Canada. The author looks to the future for the drying and possibly cultivation and extraction of chemicals by geothermal heat from seaweeds and various other heat sensitive products available in Iceland. Without geothermal energy seaweed industry would not exist in Iceland nor would this paper.« less

Reporting from the Iceland Deep Drilling Project

NASA Astrophysics Data System (ADS)

Urban, Karl

2017-04-01

Geoscience-related topics are in many cases difficult to communicate to the public: Often they include dead soil which not easily tells lively stories. And it is hard to sell those topics to editors of public media. In addition the topics might also be politically supercharged if they are resource-related with a visible environmental impact. Therefore any researcher involved might be overcautious while talking to journalists. With a grant from the EGU Science Journalist Fellowship I travelled to Iceland in autumn 2016 to report about the Iceland Deep Drilling Project (IDDP). The project which started just weeks prior to my arrival aimed to drill the deepest borehole in a volcanically active region. During earlier trials the borehole collapsed or the drill string unintentionally hit magma. If successful the IDDP promises a much higher level of geothermal energy harvested. The IDDP was therefore ideally suited to be sold to public media outlets since Iceland's volcanic legacy easily tells a lively story. But the drilling's potential environmental impact makes it a political topic in Iceland - even though geothermal energy has a positive public perception. Therefore the IDDP included some pitfalls I observed several times before while reporting about geoscience research. Those could be circumvented if researchers and journalists knew better about their expectations before any interview takes place.

A Revised Earthquake Catalogue for South Iceland

NASA Astrophysics Data System (ADS)

Panzera, Francesco; Zechar, J. Douglas; Vogfjörd, Kristín S.; Eberhard, David A. J.

2016-01-01

In 1991, a new seismic monitoring network named SIL was started in Iceland with a digital seismic system and automatic operation. The system is equipped with software that reports the automatic location and magnitude of earthquakes, usually within 1-2 min of their occurrence. Normally, automatic locations are manually checked and re-estimated with corrected phase picks, but locations are subject to random errors and systematic biases. In this article, we consider the quality of the catalogue and produce a revised catalogue for South Iceland, the area with the highest seismic risk in Iceland. We explore the effects of filtering events using some common recommendations based on network geometry and station spacing and, as an alternative, filtering based on a multivariate analysis that identifies outliers in the hypocentre error distribution. We identify and remove quarry blasts, and we re-estimate the magnitude of many events. This revised catalogue which we consider to be filtered, cleaned, and corrected should be valuable for building future seismicity models and for assessing seismic hazard and risk. We present a comparative seismicity analysis using the original and revised catalogues: we report characteristics of South Iceland seismicity in terms of b value and magnitude of completeness. Our work demonstrates the importance of carefully checking an earthquake catalogue before proceeding with seismicity analysis.

Iceland as a demonstrator for a transition to low carbon economy?

NASA Astrophysics Data System (ADS)

Asbjornsson, Einar Jon; Stefansson, Hlynur; Finger, David Christian

2017-04-01

The energy supply in Iceland is quite unique, about 85% of the total primary energy is coming from renewable resources. Nevertheless, the ecological footprint of an average Icelander is with 6.5 worlds, one of the highest worldwide and the energy consumption per capita is about 7 times higher than the European average. Recent developments have shown that there is a great potential to reduce the footprint and develop towards low carbon economy. With its small population, well educated and governed society and clear system boundaries to the outside world, Iceland is a good research laboratory and an ideal demonstrator for a transition towards a low carbon economy. This presentation will outline how several innovative research projects at Reykjavik University could lead Iceland towards a sustainable and low carbon economy. The presentations will conclude with a visionary outlook how Iceland can become a demonstration nation towards a prosperous, low carbon and sustainable economy, helping stabilize global warming at an acceptable level.

Evolution of Devonian carbonate-shelf margin, Nevada

USGS Publications Warehouse

Morrow, J.R.; Sandberg, C.A.

2008-01-01

The north-trending, 550-km-long Nevada segment of the Devonian carbonate-shelf margin, which fringed western North America, evidences the complex interaction of paleotectonics, eustasy, biotic changes, and bolide impact-related influences. Margin reconstruction is complicated by mid-Paleozoic to Paleogene compressional tectonics and younger extensional and strike-slip faulting. Reports published during the past three decades identify 12 important events that influenced development of shelf-margin settings; in chronological order, these are: (1) Early Devonian inheritance of Silurian stable shelf inargin, (2) formation of Early to early Middle 'Devonian shelf-margin basins, (3) propradation of later Middle Devonian shelf margin, (4) late Middle Devonian Taghanic ondap and continuing long-term Frasnian transgression, (5) initiation of latest Middle Devonian to early Frasnian proto-Antler orogenic forebulge, (6) mid-Frasnian Alamo Impact, (7) accelerated development of proto-Antler forebulge and backbulge Pilot basin, (8) global late Frasnian sentichatovae sea-level rise, (9) end-Frasnian sea-level fluctuations and ensuing mass extinction, (10) long-term Famennian regression and continept-wide erosion, (11) late Famennian emergence: of Ahtler orogenic highlands, and (12) end-Devonian eustatic sea-level fall. Although of considerable value for understanding facies relationships and geometries, existing standard carbonate platform-margin models developed for passive settings else-where do not adequately describe the diverse depositional and, structural settings along the Nevada Devonian platform margin. Recent structural and geochemical studies suggest that the Early to Middle Devonian-shelf-margin basins may have been fault-bound and controlled by inherited Precambrian structure. Subsequently, the migrating latest Middle to Late Devonian Antler orogenic forebulge exerted a dominant control on shelf-margin position, morphology, and sedimentation. ??Geological Society of

The psychometric testing of the Nursing Teamwork Survey in Iceland.

PubMed

Bragadóttir, Helga; Kalisch, Beatrice J; Smáradóttir, Sigríður Bríet; Jónsdóttir, Heiður Hrund

2016-06-01

The purpose of this study was to test the psychometric properties of the Nursing Teamwork Survey-Icelandic (NTS-Icelandic), which was translated from US English to Icelandic. The Nursing Teamwork Survey, with 33 items, measures overall teamwork and five factors of teamwork: trust, team orientation, backup, shared mental models, and team leadership. The psychometric testing of the NTS-Icelandic was carried out on data from a pilot study and a national study. The sample for a pilot study included 123 nursing staff from five units, and the sample for a national study included 925 nursing staff from 27 inpatient units. The overall test-retest intraclass correlation coefficient in the pilot study was 0.693 (lower bound = 0.498, upper bound = 0.821) (p < 0.001). The Cronbach's alpha reliability for the total scale and subscales ranged from 0.737 to 0.911. A confirmatory factor analysis indicated a good fit of the data from the national study with the five-factor model for nursing teamwork. The NTS-Icelandic tested valid and reliable in this study. Study findings support further use of the Nursing Teamwork Survey internationally. © 2016 John Wiley & Sons Australia, Ltd.

Distribution of dust during two dust storms in Iceland

NASA Astrophysics Data System (ADS)

Ösp Magnúsdóttir, Agnes; Dagsson-Waldhauserova, Pavla; Arnalds, Ólafur; Ólafsson, Haraldur

2017-04-01

Particulate matter mass concentrations and size fractions of PM1, PM2.5, PM4, PM10, and PM15 measured in transversal horizontal profile of two dust storms in southwestern Iceland are presented. Images from a camera network were used to estimate the visibility and spatial extent of measured dust events. Numerical simulations were used to calculate the total dust flux from the sources as 180,000 and 280,000 tons for each storm. The mean PM15 concentrations inside of the dust plumes varied from 10 to 1600 ?g?m?3 (PM10 = 7 to 583 ?g?m?3). The mean PM1 concentrations were 97-241 ?g?m?3 with a maximum of 261 ?g?m?3 for the first storm. The PM1/PM2.5 ratios of >0.9 and PM1/PM10 ratios of 0.34-0.63 show that suspension of volcanic materials in Iceland causes air pollution with extremely high PM1 concentrations, similar to polluted urban areas in Europe or Asia. Icelandic volcanic dust consists of a higher proportion of submicron particles compared to crustal dust. Both dust storms occurred in relatively densely inhabited areas of Iceland. First results on size partitioning of Icelandic dust presented here should challenge health authorities to enhance research in relation to dust and shows the need for public dust warning systems.

Erosive and Mechanical Tooth Wear in Viking Age Icelanders.

PubMed

Richter, Svend; Eliasson, Sigfus Thor

2017-08-29

(1) Background: The importance of the Icelandic Sagas as a source of information about diet habits in medieval Iceland, and possibly other Nordic countries, is obvious. Extensive tooth wear in archaeological material worldwide has revealed that the main cause of this wear is believed to have been a coarse diet. Near the volcano Hekla, 66 skeletons dated from before 1104 were excavated, and 49 skulls could be evaluated for tooth wear. The purpose of this study was to determine the main causes of tooth wear in light of diet and beverage consumption described in the Sagas; (2) Materials and methods: Two methods were used to evaluate tooth wear and seven for age estimation; (3) Results: Extensive tooth wear was seen in all of the groups, increasing with age. The first molars had the highest score, with no difference between sexes. These had all the similarities seen in wear from a coarse diet, but also presented with characteristics that are seen in erosion in modern Icelanders, through consuming excessive amounts of soft drinks. According to the Sagas, acidic whey was a daily drink and was used for the preservation of food in Iceland, until fairly recently; (4) Conclusions: It is postulated that the consumption of acidic drinks and food, in addition to a coarse and rough diet, played a significant role in the dental wear seen in ancient Icelanders.

Erosive and Mechanical Tooth Wear in Viking Age Icelanders

PubMed Central

Eliasson, Sigfus Thor

2017-01-01

(1) Background: The importance of the Icelandic Sagas as a source of information about diet habits in medieval Iceland, and possibly other Nordic countries, is obvious. Extensive tooth wear in archaeological material worldwide has revealed that the main cause of this wear is believed to have been a coarse diet. Near the volcano Hekla, 66 skeletons dated from before 1104 were excavated, and 49 skulls could be evaluated for tooth wear. The purpose of this study was to determine the main causes of tooth wear in light of diet and beverage consumption described in the Sagas; (2) Materials and methods: Two methods were used to evaluate tooth wear and seven for age estimation; (3) Results: Extensive tooth wear was seen in all of the groups, increasing with age. The first molars had the highest score, with no difference between sexes. These had all the similarities seen in wear from a coarse diet, but also presented with characteristics that are seen in erosion in modern Icelanders, through consuming excessive amounts of soft drinks. According to the Sagas, acidic whey was a daily drink and was used for the preservation of food in Iceland, until fairly recently; (4) Conclusions: It is postulated that the consumption of acidic drinks and food, in addition to a coarse and rough diet, played a significant role in the dental wear seen in ancient Icelanders. PMID:29563430

Planetary geomorphology field studies: Iceland and Antarctica

NASA Technical Reports Server (NTRS)

Malin, M. C.

1984-01-01

Field studies of terrestrial landforms and the processes that shape them provide new directions to the study of planetary features. These studies, conducted in Iceland and in Antarctica, investigated physical and chemical weathering mechanisms and rates, eolitan processes, mudflow phenomena, drainage development, and catastrophic fluvial and volcanic phenomena. Continuing investigations in Iceland fall in three main catagories: (1) catastrophic floods of the Jokulsa a Fjollum, (2) lahars associated with explosive volcanic eruptions of Askja caldera, and (3) rates of eolian abrasion in cold, volcanic deserts. The ice-free valleys of Antarctica, in particular those in South Victoria Land, have much is common with the surface of Mars. In addition to providing independent support for the application of the Iceland findings to consideration of the martian erosional system, the Antarctic observations also provide analogies to other martian phenomena. For example, a family of sand dunes in Victoria Valley are stabilized by the incorporation of snow as beds.

Do Processes of Rhyolite Genesis Change as Icelandic Rifts Drift off of the Plume?

NASA Astrophysics Data System (ADS)

Jordan, B. T.

2004-12-01

The abandoned Snaefellsnes rift zone in western Iceland was the on-land manifestation of the Mid-Atlantic Ridge between 15 and 7 Ma. The rift zone was abandoned at 7 Ma, after it had drifted westward off of the Iceland hotspot, generally interpreted as a mantle plume. The position of the abandoned rift was initially recognized as the axis of a regional syncline analogous to the syncline developed in response to active rifting. Previous paleomagnetic and geochronologic studies have confirmed the position of the abandoned rift axis. Recent seismic tomography shows that the abandoned rift is also characterized by relatively thin crust (<20 km, versus up to 46 km above the plume). In the context of supervising Keck Geology Consortium undergraduate research projects in northwestern Iceland in 2003 and 2004, I have studied several silicic centers erupted at different times along the northern Snaefellsnes rift. A compilation of preliminary geochemical data from the Skagi area near the rift reveals several interesting trends that bear on the origin of silicic magmas as activity in the rift was waning. The compositional spectrum of silicic rocks in this area is from dacite (67 wt.% SiO2) to rhyolite (75 wt.% SiO2). Positive correlation between Na2O and SiO2 is consistent with either fractionation or decreasing degrees of crustal melting to get from dacite to rhyolite. However, Zr correlates negatively with SiO2, consistent with zircon fractionation, but inconsistent with variation in the degree of melting unless zircon is present in the source, unlikely for the meta-basaltic crust of Iceland. Therefore, I suggest these rocks reflect extreme (>90%) fractionation of a basaltic parent. A similar argument was advanced by Furman et al. (1992, J. Pet., 1405-1445) for rhyolites at Austerhorn in eastern Iceland. Compelling arguments have been previously advanced that most rhyolites erupted in the modern rifts of Iceland are the products of crustal melting. The same has been argued

The Mathematical Content Knowledge of Prospective Teachers in Iceland

ERIC Educational Resources Information Center

Johannsdottir, Bjorg

2013-01-01

This study focused on the mathematical content knowledge of prospective teachers in Iceland. The sample was 38 students in the School of Education at the University of Iceland, both graduate and undergraduate students. All of the participants in the study completed a questionnaire survey and 10 were interviewed. The choice of ways to measure the…

Capture-recapture abundance and survival estimates of three cetacean species in Icelandic coastal waters using trained scientist-volunteers

NASA Astrophysics Data System (ADS)

Bertulli, Chiara G.; Guéry, Loreleï; McGinty, Niall; Suzuki, Ailie; Brannan, Naomi; Marques, Tania; Rasmussen, Marianne H.; Gimenez, Olivier

2018-01-01

Knowledge of abundance and survival of humpback whales, white-beaked dolphins and minke whales are essential to manage and conserve these species in Icelandic coastal shelf waters. Our main goal was to test the feasibility of employing inexpensive research methods (data collected by trained-scientist volunteers onboard opportunistic vessels) to assess abundance and apparent survival. No previous studies in Iceland have investigated these two demographic parameters in these three cetacean species using open capture-recapture models accounting for imperfect and possibly heterogeneous detection. A transient effect was accounted for whenever required to estimate the population of resident individuals. Identification photographs were collected by scientist-trained volunteers for 7 years (2006-2013) from onboard commercial whale-watching vessels in the coastal waters of Faxaflói (southwest coast, 4400 km2) and Skjálfandi (northeast coast, 1100 km2), Iceland. We estimated an average abundance of 83 humpback whales (Mn; 95% confidence interval: 54-130) in Skjálfandi; 238 white-beaked dolphins (La; [163-321]) in Faxaflói; and 67 minke whales (Ba; [53-82]) in Faxaflói and 24 (14-31) in Skjálfandi. We also found that apparent survival was constant for all three species (Mn: 0.52 [0.41-0.63], La: 0.79 [0.64-0.88], Ba-Faxaflói: 0.80 [0.67-0.88], Ba-Skjálfandi: 0.96 [0.60-0.99]). Our results showed inter-annual variation in abundance estimates which were small for all species, and the presence of transience for minke whales. A significant increase in abundance during the study period was solely found in minke whale data from Skjálfandi. Humpback whales and white-beaked dolphins showed lower apparent survival rates compared to similar baleen whale and dolphin populations. Our results show data collected by trained-scientist volunteers can produce viable estimates of abundance and survival although bias in the methods we employed exist and need to be addressed. With the

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

article title:  Eyjafjallajökull Volcano Plume Heights     View ... and stereo plume   Iceland's Eyjafjallajökull volcano produced its second major ash plume of 2010 beginning on May 7. Unlike ...

Isotope and fatty acid trends along continental shelf depth gradients: Inshore versus offshore hydrological influences on benthic trophic functioning

NASA Astrophysics Data System (ADS)

Chouvelon, T.; Schaal, G.; Grall, J.; Pernet, F.; Perdriau, M.; A-Pernet, E. J.; Le Bris, H.

2015-11-01

Anthropogenic activities and land-based inputs into the sea may influence the trophic structure and functioning of coastal and continental shelf ecosystems, despite the numerous opportunities and services the latter offer to humans and wildlife. In addition, hydrological structures and physical dynamics potentially influence the sources of organic matter (e.g., terrestrial versus marine, or fresh material versus detrital material) entering marine food webs. Understanding the significance of the processes that influence marine food webs and ecosystems (e.g., terrestrial inputs, physical dynamics) is crucially important because trophic dynamics are a vital part of ecosystem integrity. This can be achieved by identifying organic matter sources that enter food webs along inshore-offshore transects. We hypothesised that regional hydrological structures over wide continental shelves directly control the benthic trophic functioning across the shelf. We investigated this issue along two transects in the northern ecosystem of the Bay of Biscay (north-eastern Atlantic). Carbon and nitrogen stable isotope analysis (SIA) and fatty acid analysis (FAA) were conducted on different complementary ecosystem compartments that include suspended particulate organic matter (POM), sedimentary organic matter (SOM), and benthic consumers such as bivalves, large crustaceans and demersal fish. Samples were collected from inshore shallow waters (at ∼1 m in depth) to more than 200 m in depth on the offshore shelf break. Results indicated strong discrepancies in stable isotope (SI) and fatty acid (FA) compositions in the sampled compartments between inshore and offshore areas, although nitrogen SI (δ15N) and FA trends were similar along both transects. Offshore the influence of a permanently stratified area (described previously as a ;cold pool;) was evident in both transects. The influence of this hydrological structure on benthic trophic functioning (i.e., on the food sources available for

Changing prevalence of hepatitis B virus genotypes in Iceland.

PubMed

Björnsdottir, Thora B; Stanzeit, Barbara; Sällberg, Matti; Löve, Arthur; Hultgren, Catharina

2005-12-01

At present eight hepatitis B virus (HBV) genotypes have been characterized: A to H. The most common genotype in Northern Europe is genotype A. So far there is no record of the specific HBV genotype distribution in Iceland. Iceland has a small population whose homogeneity has changed due to increasing migration during the past decades. The distribution of HBV genotypes in Iceland was analyzed using sera from 170 Icelandic patients. The samples were obtained before 1989, during an HBV epidemic among intravenous drug users in 1989 to 1992 and after 1994. A fragment of the HBV S-gene was amplified, sequenced and subjected to phylogenetic analysis. Among samples derived before 1989 genotypes A, C, and D were found. Most of the samples diagnosed during the epidemic belonged to genotype D and a smaller portion to genotype A. This suggests that the epidemic was most likely caused either by an endogenous HBV strain or by a strain imported from Europe or the USA. Among samples obtained after 1994, genotypes A to E and G were found, but the majority were of genotypes A, C, and D. This is consistent with an increase in migration and immigration from regions in Asia and Africa during the past 10 years. Thus, the changing prevalence of HBV genotypes in a small isolated community such as Iceland reflects the influence of migration and increasing contacts with regions outside the Western World. Copyright (c) 2005 Wiley-Liss, inc.

Plume-driven plumbing and crustal formation in Iceland

USGS Publications Warehouse

Allen, R.M.; Nolet, G.; Morgan, W.J.; Vogfjord, K.; Nettles, M.; Ekstrom, G.; Bergsson, B.H.; Erlendsson, P.; Foulger, G.R.; Jakobsdottir, S.; Julian, B.R.; Pritchard, M.; Ragnarsson, S.; Stefansson, R.

2002-01-01

Through combination of surface wave and body wave constraints we derive a three-dimensional (3-D) crustal S velocity model and Moho map for Iceland. It reveals a vast plumbing system feeding mantle plume melt into upper crustal magma chambers where crustal formation takes place. The method is based on the partitioned waveform inversion to which we add additional observations. Love waves from six local events recorded on the HOTSPOT-SIL networks are fitted, Sn travel times from the same events measured, previous observations of crustal thickness are added, and all three sets of constraints simultaneously inverted for our 3-D model. In the upper crust (0-15 km) an elongated low-velocity region extends along the length of the Northern, Eastern and Western Neovolcanic Zones. The lowest velocities (-7%) are found at 5-10 km below the two most active volcanic complexes: Hekla and Bardarbunga-Grimsvotn. In the lower crust (>15 km) the low-velocity region can be represented as a vertical cylinder beneath central Iceland. The low-velocity structure is interpreted as the thermal halo of pipe work which connects the region of melt generation in the uppermost mantle beneath central Iceland to active volcanoes along the neovolcanic zones. Crustal thickness in Iceland varies from 15-20 km beneath the Reykjanes Peninsula, Krafla and the extinct Snfellsnes rift zone, to 46 km beneath central Iceland. The average crustal thickness is 29 km. The variations in thickness can be explained in terms of the temporal variation in plume productivity over the last ~20 Myr, the Snfellsnes rift zone being active during a minimum in plume productivity. Variations in crustal thickness do not depart significantly from an isostatically predicted crustal thickness. The best fit linear isostatic relation implies an average density jump of 4% across the Moho. Rare earth element inversions of basalt compositions on Iceland suggest a melt thickness (i.e., crustal thickness) of 15-20 km, given passive

Mesozoic evolution of northeast African shelf margin, Libya and Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aadland, R.K.; Schamel, S.

1989-03-01

The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. The 250 km-wide and highly differentiated Mesozoic passive margin in the Western Desert region of Egypt is developed above a broad northwest-trending Late Carboniferous basement arch. In northeastern Libya, in contrast, the passive margin is restricted to just the northernmost Cyrenaica platform, where subsidence was extremely rapid in the Jurassic and Early Cretaceous. The boundary between the Western Desertmore » basin and the Cyrenaica platform is controlled by the western flank of the basement arch. In the middle Cretaceous (100-90 Ma), subsidence accelerated over large areas of the Western desert, further enhancing a pattern of east-west-trending subbasins. This phase of rapid subsidence was abruptly ended about 80 Ma by the onset of structural inversion that uplifted the northern Cyrenaica shelf margin and further differentiated the Western Desert subbasin along a northeasterly trend.« less

CO2-rich geothermal areas in Iceland as natural analogues for geologic carbon sequestration

NASA Astrophysics Data System (ADS)

Thomas, D.; Maher, K.; Bird, D. K.; Brown, G. E.; Arnorsson, S.

2013-12-01

Geologic CO2 sequestration into mafic rocks via silicate mineral dissolution and carbonate precipitation has been suggested as a way to mitigate industrial CO2 emissions by storing CO2 in a stable form. Experimental observations of irreversible reaction of basalt with supercritical or gaseous and aqueous CO2 have resulted in carbonate precipitation, but there are no universal trends linking the extent of mineralization and type of reaction products to the bulk rock composition, glass percentage or mineralogy of the starting material. Additionally, concern exists that CO2 leakage from injection sites and migration through the subsurface may induce mineral dissolution and desorption of trace elements, potentially contaminating groundwater. This study investigates low-temperature (≤180°C) basaltic geothermal areas in Iceland with an anomalously high input of magmatic CO2 as natural analogues of the geochemical processes associated with the injection of CO2 into mafic rocks and possible leakage. Fluids that contain >4 mmol/kg total CO2 are common along the divergent Snæfellsnes Volcanic Zone in western Iceland and within the South Iceland Seismic Zone in southwest Iceland. The meteorically derived waters contain up to 80 mmol/kg dissolved inorganic carbonate (DIC). The aqueous concentration of major cations and trace elements is greater than that in Icelandic surface and groundwater and increases with DIC and decreasing pH. Concentrations of As and Ni in some samples are several times the World Health Organization (WHO) guidelines for safe drinking water. Thermodynamic modeling indicates that waters approach saturation with respect to calcite and/or aragonite, kaolinite and amorphous silica, and are undersaturated with respect to plagioclase feldspar, clinozoisite and Ca-zeolites. Petrographic study of drill cuttings from wells that intersect the CO2-rich areas indicates that the sites have undergone at least two stages of hydrothermal alteration: initial high

Interannual Variability of the Patagonian Shelf Circulation and Cross-Shelf Exchange

NASA Astrophysics Data System (ADS)

Combes, V.; Matano, R. P.

2016-02-01

Observational studies have already established the general mean circulation and hydrographic characteristics of the Patagonian shelf waters using data from in situ observation, altimetry and more recently from the Aquarius satellite sea surface salinity, but the paucity of those data in time or below the surface leave us with an incomplete picture of the shelf circulation and of its variability. This study discusses the variability of the Patagonian central shelf circulation and off-shelf transport using a high-resolution model experiment for the period 1979-2012. The model solution shows high skill in reproducing the best-known aspects of the shelf and deep-ocean circulations. This study links the variability of the central shelf circulation and off-shelf transport to the wind variability, southern shelf transport variability and large-scale current variability. We find that while the inner and central shelf circulation are principally wind driven, the contribution of the Brazil/Malvinas Confluence (BMC) variability becomes important in the outer shelf and along the shelf break. The model also indicates that whereas the location of the off-shelf transport is controlled by the BMC, its variability is modulated by the southern shelf transport. The variability of the subtropical shelf front, where the fresh southern shelf waters encounters the saline northern shelf waters, is also presented in this study.

Interannual Variability in Amundsen Sea Ice-Shelf Height Change Linked to ENSO

NASA Astrophysics Data System (ADS)

Paolo, F. S.; Fricker, H. A.; Padman, L.

2015-12-01

Atmospheric and sea-ice conditions around Antarctica, particularly in the Amundsen and Bellingshausen seas, respond to climate dynamics in the tropical Pacific Ocean on interannual time scales including the El Nino-Southern Oscillation (ENSO). It has been hypothesized that the mass balance of the Antarctic Ice Sheet, including its floating ice shelves, also responds to this climate signal; however, this has not yet been unambiguously demonstrated. We apply multivariate singular spectrum analysis (MSSA) to our 18-year (1994-2012) time series of ice-shelf height in the Amundsen Sea (AS) region. This advanced spectral method distinguishes between regular deterministic behavior ("cycles") at sub-decadal time scale and irregular behavior ("noise") at shorter time scales. Although the long-term trends of AS ice-shelf height changes are much larger than the range of interannual variability, the short-term rate of change dh/dt can vary about the trend by more than 50%. The mode of interannual variability in the AS ice-shelf height is strongly correlated with the low-frequency mode of ENSO (periodicity of ~4.5 years) as represented by the Southern Oscillation Index. The ice-shelf height in the AS is expected to respond to changes in precipitation and inflows of warm subsurface Circumpolar Deep Water (CDW) into the ocean cavities under the ice shelves, altering basal melt rates. Since both of these processes affecting ice-shelf mass balance respond to changes in wind fields for different ENSO states, we expect some correlation between them. We will describe the spatial structure of AS ice-shelf height response to ENSO, and attempt to distinguish the precipitation signal from basal mass balance due to changing CDW inflows.

Holocene and latest Pleistocene climate and glacier fluctuations in Iceland

NASA Astrophysics Data System (ADS)

Geirsdóttir, Áslaug; Miller, Gifford H.; Axford, Yarrow; Ólafsdóttir, Sædís

2009-10-01

Multiproxy climate records from Iceland document complex changes in terrestrial climate and glacier fluctuations through the Holocene, revealing some coherent patterns of change as well as significant spatial variability. Most studies on the Last Glacial Maximum and subsequent deglaciation reveal a dynamic Iceland Ice Sheet (IIS) that responded abruptly to changes in ocean currents and sea level. The IIS broke up catastrophically around 15 ka as the Polar Front migrated northward and sea level rose. Indications of regional advance or halt of the glaciers are seen in late Alleröd/early Younger Dryas time and again in PreBoreal time. Due to the apparent rise of relative sea level in Iceland during this time, most sites contain evidence for fluctuating, tidewater glacier termini occupying paleo fjords and bays. The time between the end of the Younger Dryas and the Preboreal was characterized by repeated jökulhlaups that eroded glacial deposits. By 10.3 ka, the main ice sheet was in rapid retreat across the highlands of Iceland. The Holocene thermal maximum (HTM) was reached after 8 ka with land temperatures estimated to be 3 °C higher than the 1961-1990 reference, and net precipitation similar to modern. Such temperatures imply largely ice-free conditions across Iceland in the early to mid-Holocene. Several marine and lacustrine sediment climate proxies record substantial summer temperature depression between 8.5 and 8 ka, but no moraines have been detected from that time. Termination of the HTM and onset of Neoglacial cooling took place sometime after 6 ka with increased glacier activity between 4.5 and 4.0 ka, intensifying between 3.0 and 2.5 ka. Although a distinct warming during the Medieval Warm Period is not dramatically apparent in Icelandic records, the interval from ca AD 0 to 1200 is commonly characterized by relative stability with slow rates of change. The literature most commonly describes Little Ice Age moraines (ca AD 1250-1900) as representing the

Asymmetric seafloor spreading on the Reykjanes Ridge - influence of the Iceland anomaly?

NASA Astrophysics Data System (ADS)

Benediktsdóttir, Ásdís; Hey, Richard; Martinez, Fernando; Höskulddson, Ármann

2017-04-01

Recently it has been shown that the crustal accretion on the Reykjanes Ridge (RR) is asymmetric with more lithosphere being consistently transferred from the Eurasian Plate to the North American Plate. In Iceland, the center of spreading has moved to the east, creating an age-asymmetry on Iceland, with more lithosphere on the North American side than the Eurasian side. The eastward movement of the spreading center is likely explained by the presence of the Iceland anomaly; if the anomaly is fixed with respect to the plate movements then the ridge system is drifting to the west and therefore the shift of the system is to the east, toward the Iceland anomaly. The shift of the center of spreading in Iceland must somehow be observed in the ridge systems off shore. We argue that the asymmetry on the RR south of Iceland, as observed in the magnetic data, is a result of the spreading center movements in Iceland. The RR extends down to the 15 km long right-lateral Bight Transform Fault (BTF) 1000 km south of south Iceland. Although it is short, it is a a sturdy and long lived offset, dating back to at least 37 Ma when spreading ceased in the Labrador Sea, and before that it was a triple junction between the North America-Greenland-Eurasia plates. Just south of the BTF, asymmetries in the magnetic data have been documented. The asymmetry is consistent to what is occurring in Iceland. Lithosphere is being transferred from the Eurasia Plate to the North America Plate. The question arises whether this is an influence of the Iceland anomaly? How far from Iceland do the influence of its anomaly reach and how to we quantify them? The off-shore asymmetries discussed here are not continuous, but seen in the magnetic fabric as if the ridge center was transferred a few kilometers, consistently to the east. A continuous asymmetry would have a different magnetic signature. The best documented asymmetry producing mechanism is a propagating rift (e.g. the Galapagos propagator). The

U.S. and Icelandic College Student Attitudes toward Relationships/Sexuality

ERIC Educational Resources Information Center

Freysteinsdóttir, Freydís Jóna; Skúlason, Sigurgrímur; Halligan, Caitlin; Knox, David

2014-01-01

Seven hundred and twenty-two undergraduates from a large southeastern university in the U.S. and 368 undergraduates from The University of Iceland in the Reykjavik, Iceland completed a 100 item Internet questionnaire revealing their (mostly white and 20-24 years old) attitudes on various relationship and sexual issues. Significant differences…

Creativity and Innovation in Iceland: Individual, Environmental, and Cultural Variables

ERIC Educational Resources Information Center

Kerr, Barbara A.; Birdnow, Maxwell; Hallaert, Jenelle; Alexander, Keely; Malmsten, Robyn; Stull, Olivia; Wright, J. D.; Lucas, Brittany; Swanson, Rachel; Claiborn, Grace J.

2017-01-01

This comprehensive literature review (CLR) is an analysis and synthesis of literature, observations, interviews, and artifacts as a means to answer the question, "Why is Iceland so innovative?" Iceland is considered by international indices as a leading nation in innovation in many fields, including design, music, art, and literature. A…

The Origin of Noble Gas Isotopic Heterogeneity in Icelandic Basalts

NASA Technical Reports Server (NTRS)

Dixon, E. T.; Honda, M.; McDougall, I.

2001-01-01

Two models for generation of heterogeneous He, Ne and Ar isotopic ratios in Icelandic basalts are evaluated using a mixing model and the observed noble gas elemental ratios in Icelandic basalts,Ocean island Basalt (OIBs) and Mid-Ocean Ridge Basalt (MORBs). Additional information is contained in the original extended abstract.

Basaltic cannibalism at Thrihnukagigur volcano, Iceland

NASA Astrophysics Data System (ADS)

Hudak, M. R.; Feineman, M. D.; La Femina, P. C.; Geirsson, H.

2014-12-01

Magmatic assimilation of felsic continental crust is a well-documented, relatively common phenomenon. The extent to which basaltic crust is assimilated by magmas, on the other hand, is not well known. Basaltic cannibalism, or the wholesale incorporation of basaltic crustal material into a basaltic magma, is thought to be uncommon because basalt requires more energy than higher silica rocks to melt. Basaltic materials that are unconsolidated, poorly crystalline, or palagonitized may be more easily ingested than fully crystallized massive basalt, thus allowing basaltic cannibalism to occur. Thrihnukagigur volcano, SW Iceland, offers a unique exposure of a buried cinder cone within its evacuated conduit, 100 m below the main vent. The unconsolidated tephra is cross-cut by a NNE-trending dike, which runs across the ceiling of this cave to a vent that produced lava and tephra during the ~4 Ka fissure eruption. Preliminary petrographic and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) analyses indicate that there are two populations of plagioclase present in the system - Population One is stubby (aspect ratio < 1.7) with disequilibrium textures and low Ba/Sr ratios while Population Two is elongate (aspect ratio > 2.1), subhedral to euhedral, and has much higher Ba/Sr ratios. Population One crystals are observed in the cinder cone, dike, and surface lavas, whereas Population Two crystals are observed only in the dike and surface lavas. This suggests that a magma crystallizing a single elongate population of plagioclase intruded the cinder cone and rapidly assimilated the tephra, incorporating the stubbier population of phenocrysts. This conceptual model for basaltic cannibalism is supported by field observations of large-scale erosion upward into the tephra, which is coated by magma flow-back indicating that magma was involved in the thermal etching. While the unique exposure at Thrihnukagigur makes it an exceptional place to investigate basaltic

Ancient genomes from Iceland reveal the making of a human population.

PubMed

Ebenesersdóttir, S Sunna; Sandoval-Velasco, Marcela; Gunnarsdóttir, Ellen D; Jagadeesan, Anuradha; Guðmundsdóttir, Valdís B; Thordardóttir, Elísabet L; Einarsdóttir, Margrét S; Moore, Kristjan H S; Sigurðsson, Ásgeir; Magnúsdóttir, Droplaug N; Jónsson, Hákon; Snorradóttir, Steinunn; Hovig, Eivind; Møller, Pål; Kockum, Ingrid; Olsson, Tomas; Alfredsson, Lars; Hansen, Thomas F; Werge, Thomas; Cavalleri, Gianpiero L; Gilbert, Edmund; Lalueza-Fox, Carles; Walser, Joe W; Kristjánsdóttir, Steinunn; Gopalakrishnan, Shyam; Árnadóttir, Lilja; Magnússon, Ólafur Þ; Gilbert, M Thomas P; Stefánsson, Kári; Helgason, Agnar

2018-06-01

Opportunities to directly study the founding of a human population and its subsequent evolutionary history are rare. Using genome sequence data from 27 ancient Icelanders, we demonstrate that they are a combination of Norse, Gaelic, and admixed individuals. We further show that these ancient Icelanders are markedly more similar to their source populations in Scandinavia and the British-Irish Isles than to contemporary Icelanders, who have been shaped by 1100 years of extensive genetic drift. Finally, we report evidence of unequal contributions from the ancient founders to the contemporary Icelandic gene pool. These results provide detailed insights into the making of a human population that has proven extraordinarily useful for the discovery of genotype-phenotype associations. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Does Arctic sea ice reduction foster shelf-basin exchange?

PubMed

Ivanov, Vladimir; Watanabe, Eiji

2013-12-01

salt flux leads to a threefold increase of shelf-slope volume flux below the warm core of Atlantic water. This threefold increase would be a sufficient substitute for a similar amount of dense water that currently forms in the Greenland, Iceland, and Norwegian (GIN) seas but is expected to decrease in a warming climate.

Primitive helium isotopic compositions associated with Miocene lavas from Northwest Iceland

NASA Astrophysics Data System (ADS)

Jackson, M. G.; Reinhard, A.; Blichert-Toft, J.; Price, A. A.; Kurz, M. D.; Halldorsson, S. A.

2016-12-01

Elevated 3He/4He ratios identified in hotspots globally are associated with an early-formed, less degassed mantle reservoir that resides in the deep mantle, but the origin and mechanism for the long-term preservation of this mantle domain are not well understood. The highest known terrestrial mantle-derived 3He/4He ratios (49.5 Ra) have been measured in 62 million year old lavas from Baffin Island and West Greenland, associated with the proto-Iceland plume [1]. Mid-Miocene lavas from northwest Iceland have 3He/4He ratios of up to 37 Ra [2]. Thus, the Iceland plume has tapped a high-3He/4He mantle source over much of the Cenozoic. This is important, as 182W [3] and 129Xe [4] data indicate that the high 3He/4He domain sampled by the Iceland plume formed in the early Hadean. We report new 3He/4He measurements on magmatic olivine in mid-Miocene lavas from Northwest Iceland. Fusion experiments indicate that the new, high 3He/4He ratios do not have a cosmogenic 3He contribution. New Sr, Nd, Hf, and Pb isotopic data place important constraints on the isotopic composition of the highest 3He/4He mantle domain sampled by mid-Miocene Iceland lavas. An important question is whether the highest 3He/4He lavas from Iceland have Sr-Nd-Hf-Pb isotopic compositions that overlap with those found in the high-3He/4He lavas from Baffin Island. If not, it will be important to understand the mechanism responsible for the offset in Sr-Nd-Hf-Pb isotopic compositions, and whether this also explains the lower maximum 3He/4He in mid-Miocene Icelandic lavas relative to their counterparts in Baffin Island. The new data will have implications for the preservation of primitive reservoirs in the deep mantle. [1] Stuart et al., Nature, v. 424, 2003. [2] Hilton et al., Earth Planet Sci. Lett., v. 173, 1999. [3] Rizo et al., Science, v. 352, 2016. [4] Mukhopadhyay, Nature, v. 486, 2012.

Concepts of illness in Icelandic children.

PubMed

Hansdottir, I; Malcarne, V L

1998-06-01

To investigate the development of illness concepts among healthy Icelandic children. Participants were 68 schoolchildren, 6-7, 10-11, and 14-15 years of age, and their parents. Cognitive developmental level and understanding of physical illness were assessed within a Piagetian framework. In addition, illness experience and illness behaviors (Child Illness Behavior Questionnaire) were assessed. Results were consistent with previous studies in that the development of illness concepts among Icelandic children was consistent with Piaget's theory of cognitive development. No relation was found between illness experience and understanding of illness. A more mature understanding of illness was related to willingness to report the onset of illness. The results suggest that findings from previous studies may be generalized to a broader population.

Bookshelf faulting and transform motion between rift segments of the Northern Volcanic Zone, Iceland

NASA Astrophysics Data System (ADS)

Green, R. G.; White, R. S.; Greenfield, T. S.

2013-12-01

Plate spreading is segmented on length scales from 10 - 1,000 kilometres. Where spreading segments are offset, extensional motion has to transfer from one segment to another. In classical plate tectonics, mid-ocean ridge spreading centres are offset by transform faults, but smaller 'non-transform' offsets exist between slightly overlapping spreading centres which accommodate shear by a variety of geometries. In Iceland the mid-Atlantic Ridge is raised above sea level by the Iceland mantle plume, and is divided into a series of segments 20-150 km long. Using microseismicity recorded by a temporary array of 26 three-component seismometers during 2009-2012 we map bookshelf faulting between the offset Askja and Kverkfjöll rift segments in north Iceland. The micro-earthquakes delineate a series of sub-parallel strike-slip faults. Well constrained fault plane solutions show consistent left-lateral motion on fault planes aligned closely with epicentral trends. The shear couple across the transform zone causes left-lateral slip on the series of strike-slip faults sub-parallel to the rift fabric, causing clockwise rotations about a vertical axis of the intervening rigid crustal blocks. This accommodates the overall right-lateral transform motion in the relay zone between the two overlapping volcanic rift segments. The faults probably reactivated crustal weaknesses along the dyke intrusion fabric (parallel to the rift axis) and have since rotated ˜15° clockwise into their present orientation. The reactivation of pre-existing rift-parallel weaknesses is in contrast with mid-ocean ridge transform faults, and is an important illustration of a 'non-transform' offset accommodating shear between overlapping spreading segments.

Fatal accidents in the Icelandic fishing fleet 1980-2005.

PubMed

Petursdottir, Gudrun; Hjoervar, Tryggvi; Snorrason, Hilmar

2007-01-01

The paper describes how the Icelandic fleet increased from 1980 to 2005, as well as the number of fishermen employed in the various sections of the fleet. All categories of the fleet have increased considerably in tonnage, while the number of fishermen has declined. At the same time the catch per man-year at sea has increased, rendering the Icelandic fisheries among the most efficient in the world in terms of catch and value per manpower. The number of fatalities in the Icelandic fisheries has declined steadily in this period. In absolute numbers these accidents are most common on decked vessels under 45m, but when weighed against man-years, fishermen on open boats are in greatest danger of losing their lives. The most common cause of fatalities is foundering of the vessel, which may cause multiple fatalities, then is man-over-board, followed by drowning in harbour and miscellaneous accidents. The reduction in the number of fatal accidents at sea may have several reasons. Mandatory safety and survival training of all fishermen, improved working conditions at sea, better telecommunications, constant VMS surveillance and a 24hr availability of airborne rescue teams have all helped to reduce fatalities in the Icelandic fishing fleet from 1980 until 2005.

Additional Workload or a Part of the Job? Icelandic Teachers' Discourse on Inclusive Education

ERIC Educational Resources Information Center

Gunnþórsdóttir, Hermína; Jóhannesson, Ingólfur Ásgeir

2014-01-01

The aim of this article is to examine the discourse of Icelandic compulsory school teachers on inclusive education. From 1974 and onwards, the education policy in Iceland has been towards inclusion, and Iceland is considered to be an example of a highly inclusive education system with few segregated resources for students with special educational…

Geomagnetic polarity zones for icelandic lavas

USGS Publications Warehouse

Dagley, P.; Wilson, R.L.; Ade-Hall, J. M.; Walker, G.P.L.; Haggerty, S.E.; Sigurgeirsson, T.; Watkins, N.D.; Smith, P.J.; Edwards, J.; Grasty, R.L.

1967-01-01

Analysis of cores collected from a sequence of lavas in Eastern Iceland has made possible an accurate calculation of the average rate of reversal of the Earth's magnetic field. ?? 1967 Nature Publishing Group.

Crustal structure beneath western and eastern Iceland from surface waves and receiver functions

USGS Publications Warehouse

Du, Z.; Foulger, G.R.; Julian, B.R.; Allen, R.M.; Nolet, G.; Morgan, W.J.; Bergsson, B.H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjord, K.

2002-01-01

We determine the crustal structures beneath 14 broad-band seismic stations, deployed in western, eastern, central and southern Iceland, using surface wave dispersion curves and receiver functions. We implement a method to invert receiver functions using constraints obtained from genetic algorithm inversion of surface waves. Our final models satisfy both data sets. The thickness of the upper crust, as defined by the velocity horizon Vs = 3.7 km s-1, is fairly uniform at ???6.5-9 km beneath the Tertiary intraplate areas of western and eastern Iceland, and unusually thick at 11 km beneath station HOT22 in the far south of Iceland. The depth to the base of the lower crust, as defined by the velocity horizon Vs = 4.1 km s-1 is ???20-26 km in western Iceland and ???27-33 km in eastern Iceland. These results agree with those of explosion profiles that detect a thinner crust beneath western Iceland than beneath eastern Iceland. An earlier report of a substantial low-velocity zone beneath the Middle Volcanic Zone in the lower crust is confirmed by a similar observation beneath an additional station there. As was found in previous receiver function studies, the most reliable feature of the results is the clear division into an upper sequence that is a few kilometres thick where velocity gradients are high, and a lower, thicker sequence where velocity gradients are low. The transition to typical mantle velocities is variable, and may range from being very gradational to being relatively sharp and clear. A clear Moho, by any definition, is rarely seen, and there is thus uncertainty in estimates of the thickness of the crust in many areas. Although a great deal of seismic data are now available constraining the structures of the crust and upper mantle beneath Iceland, their geological nature is not well understood.

Research on human genetics in Iceland. Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1980-10-31

Records of the Icelandic Population are being used to investigate the possible inheritance of disabilities and diseases as well as other characters and the effect of environment on man. The progress report of research covers the period 1977 to 1980. The investigation was begun in 1965 by the Genetical Committee of the University of Iceland and the materials used are demographic records from the year 1840 to present and various medical information. The records are being computerized and linked together to make them effective for use in hereditary studies.

Wind-blown volcanic ash off Iceland

NASA Image and Video Library

2017-12-08

On September 16, 2013 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite passed over the southern tip of Iceland and captured a remarkable image dust plumes blowing hundreds of kilometers over the Atlantic Ocean. The westernmost plume is dark tan in color and so thick that the blue ocean waters are obscured from view near Iceland's coast. The eastern plume appears broader, thinner and light gray in color. According to the Icelandic Met Office, near the Mýrdalsjökull and Vatnajökull ice-caps there are vast glacial outwash plains which stretch from the glacial margins to the sea. These plains, formed by melt water from glaciers, are known as sandur. Strong northerly winds frequently blow dust from the sandur plains far from the shore. This particular dust plume originates to the east of the Mýrdalsjökull ice cap. The Katla volcano, one of the largest in Iceland, lies under the Mýrdalsjökull glacier and in the general region of the westernmost plume. Katla has a history of large, violent eruptions occurring on an average of every 50-100 years. The volcano has been increasingly restless since 1999, with increased seismicity in recent years. In 2011 a very small eruption was reported, with minimal damage. Because of the increasing restlessness and the dangerous nature of historic eruptions, the volcano is currently carefully monitored. None of the monitoring agencies reported eruption at Katla in mid-September of this year. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team 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

Potential and limitation of combining terrestrial and marine growth records from Iceland

NASA Astrophysics Data System (ADS)

Piermattei, A.; Urbinati, C.; Tonelli, E.; Eggertsson, Ó.; Levanič, T.; Kaczka, R. J.; Andrew, C.; Schöne, B. R.; Büntgen, U.

2017-08-01

Seasonally formed, perennial growth increments of various organisms may possibly contain information about past environmental changes, well before instrumental measurements occurred. Such annually resolved proxy records have been mainly obtained from terrestrial archives, with a paucity of similar data originating from marine habitats. Iceland represents ideal conditions to develop both, tree ring (dendro) and bivalve shell (sclero) chronologies from adjacent sites. Here we introduce the first network of Icelandic birch (Betula pubescens Ehrh.) and rowan (Sorbus aucuparia) dendrochronologies, as well as ocean quahog (Arctica islandica L.) sclerochronologies. In order to identify the dominant external drivers of tree and shell growth, we assess the common growth trends and growth extremes within and between the terrestrial and marine records, as well as relationships of both archives with instrumental-based meteorological indices. Capturing a strong signal of June-August mean air temperature, the dendrochronologies are significantly positively correlated to each other. The sclerochronologies, however, reveal much lower growth coherency, which likely results from different sampling strategies and growth habitats. Disagreement between the dendro- and sclerochronologies possibly originates from unequal sample size, offset in the seasonal timing and rate of the growth, as well as varying sensitivities to different environmental factors. Our results emphasize the importance of considering a wide range of species and taxa to reconstruct a more complete picture of terrestrial and marine ecosystem functioning and productivity across various spatiotemporal scales.

The Iceland Plate Boundary Zone: Propagating Rifts, Migrating Transforms, and Rift-Parallel Strike-Slip Faults

NASA Astrophysics Data System (ADS)

Karson, J. A.

2017-11-01

Unlike most of the Mid-Atlantic Ridge, the North America/Eurasia plate boundary in Iceland lies above sea level where magmatic and tectonic processes can be directly investigated in subaerial exposures. Accordingly, geologic processes in Iceland have long been recognized as possible analogs for seafloor spreading in the submerged parts of the mid-ocean ridge system. Combining existing and new data from across Iceland provides an integrated view of this active, mostly subaerial plate boundary. The broad Iceland plate boundary zone includes segmented rift zones linked by transform fault zones. Rift propagation and transform fault migration away from the Iceland hotspot rearrange the plate boundary configuration resulting in widespread deformation of older crust and reactivation of spreading-related structures. Rift propagation results in block rotations that are accommodated by widespread, rift-parallel, strike-slip faulting. The geometry and kinematics of faulting in Iceland may have implications for spreading processes elsewhere on the mid-ocean ridge system where rift propagation and transform migration occur.

Geochemistry of NE Atlantic non-rifting zones, Iceland and Jan Mayen

NASA Astrophysics Data System (ADS)

Tronnes, R. G.; Waight, T.

2005-12-01

The fertile components of the NE Atlantic mantle are sampled preferentially by alkaline basalts in the volcanic flank zones of Iceland and in the Jan Mayen and Vesteris seamount areas. Our data from primitive flank zone lavas from Iceland and Jan Mayen demonstrate a HIMU-affinity with enrichment of HFSE, U/Pb, Th/U and Nb/Th. In PM-normalized spider diagrams the least enriched samples have weakly positive Sr-anomalies, whereas the most enriched samples have negative Sr-anomalies. The entire sample suite shows negative Sr-Nd-isotope correlation, whereas the samples of each volcanic system or flank zone generally lack such a correlation. Our data confirm the anomalously high 87/86Sr of the Orafajokull volcanic system in the eastern flank zone. The results are consistent with existing data for other primitive flank zone basalts from Iceland and Jan Mayen. Common geochemical features linking alkaline flank zone basalts and high-degree tholeiitic melts include high 87/86Sr (and probably 176/177Hf) for a given 143/144Nd, negative delta-207Pb (except for Orafajokull) and positive delta-Nb. Alkaline flank zone basalts have generally higher 87/86Sr, 206/204Pb and 18/16O and lower 143/144Nd, 187/188Os and 3/4He than rift zone tholeiites. The different 18/16O ratios in flank and rift zone basalts are consistent with seafloor hydrothermal alteration of the upper and lower parts of recycled oceanic lithosphere, respectively. Olivine-melt fractionation may contribute to the difference. Indications of lower 187/188Os in alkaline basalts compared to nearby rift zone tholeiites could be caused by subduction zone loss of Re from the upper part of recycled slabs. The partial melting and volcanic sampling of the fertile mantle components under Iceland and the NE Atlantic is governed by the crustal structure and geometry of the Icelandic volcanic zones and the lateral deflection of the upwelling heterogeneous mantle source originating under central Iceland. Based on the pattern of V

Internationally Educated Teachers and Student Teachers in Iceland: Two Qualitative Studies

ERIC Educational Resources Information Center

Ragnarsdottir, Hanna

2010-01-01

This article draws upon two qualitative studies with internationally educated teachers and teacher assistants in preschools in Iceland as well as ethnic minority student teachers at the Iceland University of Education. The common research question in both studies is whether the experiences of these teachers reveal barriers to integration within…

Distribution patterns in the native vascular flora of Iceland.

PubMed

Wasowicz, Pawel; Pasierbiński, Andrzej; Przedpelska-Wasowicz, Ewa Maria; Kristinsson, Hörður

2014-01-01

The aim of our study was to reveal biogeographical patterns in the native vascular flora of Iceland and to define ecological factors responsible for these patterns. We analysed dataset of more than 500,000 records containing information on the occurrence of vascular plants. Analysis of ecological factors included climatic (derived from WORLDCLIM data), topographic (calculated from digital elevation model) and geological (bedrock characteristics) variables. Spherical k-means clustering and principal component analysis were used to detect biogeographical patterns and to study the factors responsible for them. We defined 10 biotic elements exhibiting different biogeographical patterns. We showed that climatic (temperature-related) and topographic variables were the most important factors contributing to the spatial patterns within the Icelandic vascular flora and that these patterns are almost completely independent of edaphic factors (bedrock type). Our study is the first one to analyse the biogeographical differentiation of the native vascular flora of Iceland.

Gudmundur Finnbogason, "sympathetic understanding," and early Icelandic psychology.

PubMed

Pind, Jörgen L

2008-05-01

Gudmundur Finnbogason (1873-1944) was a pioneer of Icelandic psychology. He was educated at the University of Copenhagen where he finished his M.A. in 1901 in philosophy, specializing in psychology. During the years 1901-1905, Finnbogason played a major role in establishing and shaping the future of primary education in Iceland. He defended his doctoral thesis on "sympathetic understanding" at the University of Copenhagen in 1911. This work deals with the psychology of imitation. In it Finnbogason defends the view that imitation is basically perception so that there is a direct link from perception to motor behavior. Through imitation people tend to assume the countenance and demeanor of other people, thus showing, in Finnbogason's terminology, "sympathetic understanding." Finnbogason's theory of imitation in many respects anticipates contemporary approaches to the psychology of imitation. In 1918 Finnbogason became professor of applied psychology at the recently founded University of Iceland. Here he attempted to establish psychology as an independent discipline. In this he was unsuccessful; his chair was abolished in 1924.

Avian influenza virus ecology in Iceland shorebirds: intercontinental reassortment and movement.

PubMed

Hall, Jeffrey S; Hallgrimsson, Gunnar Thor; Suwannanarn, Kamol; Sreevatsen, Srinand; Ip, Hon S; Magnusdottir, Ellen; TeSlaa, Joshua L; Nashold, Sean W; Dusek, Robert J

2014-12-01

Shorebirds are a primary reservoir of avian influenza viruses (AIV). We conducted surveillance studies in Iceland shorebird populations for 3 years, documenting high serological evidence of AIV exposure in shorebirds, primarily in Ruddy Turnstones (Arenaria interpres; seroprevalence=75%). However, little evidence of virus infection was found in these shorebird populations and only two turnstone AIVs (H2N7; H5N1) were able to be phylogenetically examined. These analyses showed that viruses from Iceland shorebirds were primarily derived from Eurasian lineage viruses, yet the H2 hemagglutinin gene segment was from a North American lineage previously detected in a gull from Iceland the previous year. The H5N1 virus was determined to be low pathogenic, however the PB2 gene was closely related to the PB2 from highly pathogenic H5N1 isolates from China. Multiple lines of evidence suggest that the turnstones were infected with at least one of these AIV while in Iceland and confirm Iceland as an important location where AIV from different continents interact and reassort, creating new virus genomes. Mounting data warrant continued surveillance for AIV in wild birds in the North Atlantic, including Canada, Greenland, and the northeast USA to determine the risks of new AI viruses and their intercontinental movement in this region. Published by Elsevier B.V.

Avian influenza virus ecology in Iceland shorebirds: intercontinental reassortment and movement

USGS Publications Warehouse

Hall, Jeffrey S.; Hallgrimsson, Gunnar Thor; Suwannanarn, Kamol; Sreevatsen, Srinand; Ip, Hon S.; TeSlaa, Joshua L.; Nashold, Sean W.; Dusek, Robert J.

2014-01-01

Shorebirds are a primary reservoir of avian influenza viruses (AIV). We conducted surveillance studies in Iceland shorebird populations for 3 years, documenting high serological evidence of AIV exposure in shorebirds, primarily in Ruddy Turnstones (Arenaria interpres; seroprevalence = 75%). However, little evidence of virus infection was found in these shorebird populations and only two turnstone AIVs (H2N7; H5N1) were able to be phylogenetically examined. These analyses showed that viruses from Iceland shorebirds were primarily derived from Eurasian lineage viruses, yet the H2 hemagglutinin gene segment was from a North American lineage previously detected in a gull from Iceland the previous year. The H5N1 virus was determined to be low pathogenic, however the PB2 gene was closely related to the PB2 from highly pathogenic H5N1 isolates from China. Multiple lines of evidence suggest that the turnstones were infected with at least one of these AIV while in Iceland and confirm Iceland as an important location where AIV from different continents interact and reassort, creating new virus genomes. Mounting data warrant continued surveillance for AIV in wild birds in the North Atlantic, including Canada, Greenland, and the northeast USA to determine the risks of new AI viruses and their intercontinental movement in this region.

NASA Spacecraft Eyes Iceland Volcanic Eruption

NASA Image and Video Library

2014-09-03

On the night of Sept. 1, 2014, NASA Earth Observing 1 EO-1 spacecraft observed the ongoing eruption at Holuhraun, Iceland. This false-color image that emphasizes the hottest areas of the vent and resulting lava flows.

Injury Pattern in Icelandic Elite Male Handball Players.

PubMed

Rafnsson, Elis Thor; Valdimarsson, Örnólfur; Sveinsson, Thorarinn; Árnason, Árni

2017-10-10

To examine the incidence, type, location, and severity of injuries in Icelandic elite male handball players and compare across factors like physical characteristics and playing position. Prospective cohort study. The latter part of the preseason and the competitive season of Icelandic male handball. Eleven handball teams (185 players) from the 2 highest divisions in Iceland participated in the study. Six teams (109 players) completed the study. Injuries were recorded by the players under supervision from their team physiotherapists or coaches. Coaches recorded training exposure, and match exposure was obtained from the Icelandic and European Handball Federations. The players directly recorded potential risk factors, such as age, height, weight, previous injuries, and player position. Injury incidence and injury location and number of injury days. Recorded time-loss injuries were 86, of which 53 (62%) were acute and 33 (38%) were due to overuse. The incidence of acute injuries was 15.0 injuries/1000 hours during games and 1.1 injuries/1000 hours during training sessions. No significant difference was found in injury incidence between teams, but number of injury days did differ between teams (P = 0.0006). Acute injuries were most common in knees (26%), ankles (19%), and feet/toes (17%), but overuse injuries occurred in low back/pelvic region (39%), shoulders (21%), and knees (21%). Previous knee injuries were the only potential risk factor found for knee injury. The results indicate a higher rate of overuse injuries in low back/pelvic region and shoulders than in comparable studies.

Alcohol and labor supply: the case of Iceland.

PubMed

Asgeirsdottir, Tinna Laufey; McGeary, Kerry Anne

2009-10-01

At a time when the government of Iceland is considering privatization of alcohol sales and a reduction of its governmental fees, it is timely to estimate the potential effects of this policy change. Given that the privatization of sales coupled with a tax reduction should lead to a decrease in the unit price of alcohol, one would expect the quantity consumed to increase. While it is of interest to project the impact of the proposed bill on the market for alcohol, another important consideration is the impact that increased alcohol consumption and, more specifically, probable alcohol misuse would have on other markets in Iceland. The only available study on this subject using Icelandic data yields surprising results. Tómasson et al. (Scand J Public Health 32:47-52, 2004) unexpectedly found no effect of probable alcohol abuse on sick leave. A logical next step would be to examine the effect of probable alcohol abuse on other important labor-market outcomes. Nationally representative survey data from 2002 allow for an analysis of probable misuse of alcohol and labor-supply choices. Labor-supply choices are considered with reference to possible effects of policies already in force, as well as proposed changes to current policies. Contrary to intuition, but in agreement with the previously mentioned Icelandic study, the adverse effects of probable misuse of alcohol on employment status or hours worked are not confirmed within this sample. The reasons for the results are unclear, although some suggestions are hypothesized. Currently, data to test those theories convincingly are not available.

Lower Tertiary laterite on the Iceland-Faeroe Ridge and the Thulean land bridge

USGS Publications Warehouse

Nilsen, T.H.

1978-01-01

CORES of a lower Tertiary lateritic palaeosol resting on basalt were recovered1 from Deep Sea Drilling Project Site 336 (Leg 38) on the north-east flank of the Iceland-Faeroe Ridge (Fig. 1), a major aseismic oceanic ridge that, together with Iceland, forms the Icelandic transverse ridge 2. The transverse ridge extends from the West European continental margin to the East Greenland continental margin, forming the geographic boundary and a partial barrier to flow of water between the Norwegian-Greenland Sea to the north and the northern North Atlantic Ocean to the south. The palaeosol indicates that at least part of the Iceland-Faeroe Ridge was above sea level during early Tertiary time3. Palaeogeographic and palaeooceanographic reconstructions suggest that it formed the main part of the Thulean land bridge that connected South-east Greenland and the Faeroe islands during the early Tertiary4. This report summarises the subsidence history of the Iceland-Faeroe Ridge relative to early Tertiary seafloor spreading, basaltic volcanism, and the development of the proposed Thulean land bridge. ?? 1978 Nature Publishing Group.

Post-emplacement cooling and contraction of lava flows: InSAR observations and thermal model for lava fields at Hekla volcano, Iceland

NASA Astrophysics Data System (ADS)

Wittmann, Werner; Dumont, Stephanie; Lavallee, Yan; Sigmundsson, Freysteinn

2016-04-01

Gradual post-emplacement subsidence of lava flows has been observed at various volcanoes, e.g. Okmok volcano in Alaska, Kilauea volcano on Hawaii and Etna volcano on Sicily. In Iceland, this effect has been observed at Krafla volcano and Hekla volcano. The latter was chosen as a case study for investigating subsidence mechanisms, specifically thermal contraction. Effects like gravitational loading, clast repacking or creeping of a hot and liquid core can contribute to subsidence of emplaced lava flows, but thermal contraction is considered being a crucial effect. The extent to which it contributes to lava flow subsidence is investigated by mapping the relative movement of emplaced lava flows and flow substrate, and modeling the observed signal. The slow vegetation in Iceland is advantageous for Interferometric Synthetic Aperture Radar (InSAR) and offers great coherence over long periods after lava emplacement, expanding beyond the outlines of lava flows. Due to this reason, InSAR observations over volcanoes in Iceland have taken place for more than 20 years. By combining InSAR tracks from ERS, Envisat and Cosmo-SkyMed satellites we gain six time series with a total of 99 interferograms. Making use of the high spatial resolution, a temporal trend of vertical lava movements was investigated over a course of over 23 years over the 1991 lava flow of Hekla volcano, Iceland. From these time series, temporal trends of accumulated subsidence and subsidence velocities were determined in line of sight of the satellites. However, the deformation signal of lava fields after emplacement is vertically dominated. Subsidence on this lava field is still ongoing and subsidence rates vary from 14.8 mm/year in 1995 to about 1.0 mm/year in 2014. Fitting a simple exponential function suggests a exponential decay constant of 5.95 years. Additionally, a one-dimensional, semi-analytical model was fitted to these data. While subsidence due to phase change is calculated analytically

The impact of volcanic tephra on weathering and soil development of Icelandic Histosols, SE Iceland

NASA Astrophysics Data System (ADS)

Bonatotzky, Theresa; Ottner, Franz; Gísladóttir, Guðrún

2017-04-01

A mixture of poorly decomposed plant remains, crystalline volcanic material and intense aeolian deposition sets Icelandic Histosols apart from other Histosols in the northern hemisphere. They exhibit a unique combination of histic (organic) and andic soil characteristics. Allophane, imogolite and ferrihydrite are common minerals in Icelandic soils while layer silicates are rare. The volcanically active area south of Vatnajökull has received numerous tephra deposits of varying thickness during Holocene. Two distinct tephra layers, the light coloured rhyolitic tephra from the Öræfajökull eruption in AD 1362 and a black basaltic tephra from a Veiðivötn fissure eruption within the Bárðarbunga volcanic system in AD 1477, are well preserved in the soils. This provides a unique opportunity to study weathering behaviour of tephra deposits of different composition and to examine their contrasting mineralogy and impact on soils south of Vatnajökull glacier. The investigated soils can be classified as Histosols with plant residues as parent material and influenced by volcanic ejecta (tephra) and aeolian material. Low pH (H2O) and high organic matter (OM) content are the two dominating factors influencing their weathering behaviour. The soil organic carbon (SOC) content was found to between 16 - 31%. As OM inhibits the formation of amorphous secondary minerals, the clay content in Icelandic soils is generally low while Al-humus complexes are predominant. The soil horizons developed from rhyolitic and basaltic tephra both show differences. Investigations of the mineralogy show small evidence of weathering in the basaltic V1477 tephra, whereas the rhyolitic volcanic ejecta has hardly altered since its formation.

Carbon fluxes in North American coastal and shelf seas: Current status and trends

NASA Astrophysics Data System (ADS)

Fennel, K.; Alin, S. R.; Barbero, L.; Evans, W.; Martin Hernandez-Ayon, J. M.; Hu, X.; Lohrenz, S. E.; Muller-Karger, F. E.; Najjar, R.; Robbins, L. L.; Shadwick, E. H.; Siedlecki, S. A.; Steiner, N.; Turk, D.; Vlahos, P.; Wang, A. Z.

2016-12-01

Coastal and shelf seas represent an interface between all major components of the global carbon cycle: land, atmosphere, marine sediments and the ocean. Fluxes and transformations of carbon in coastal systems are complex and highly variable in space and time. The First State of the Carbon Cycle Report (http://cdiac.ornl.gov/SOCCR/final.html, Chapter 15, Chavez et al. 2007) concluded that carbon budgets of North American ocean margins were not well quantified because of insufficient observations and the complexity and highly localized spatial variability of coastal carbon dynamics. Since then significant progress has been made through the expansion of carbon observing networks, the implementation of modeling capabilities, and national and international coordination and synthesis activities. We will review the current understanding of coastal carbon fluxes around the North American continent including along the Atlantic and Pacific coasts, the northern Gulf of Mexico, and the North American Arctic region and provide a compilation of regional estimates of air-sea fluxes of CO2. We will discuss generalizable patterns in coastal air-sea CO2 exchange and other carbon fluxes as well as reasons underlying spatial heterogeneity. After providing an overview of the principal modes of carbon export from coastal systems, we will apply these mechanisms to the North American continent, and discuss observed and projected trends of key properties and fluxes. The presentation will illustrate that despite significant advances in capabilities and understanding, large uncertainties remain.

Diatoms as Proxies for a Fluctuating Ice Cap Margin, Hvitarvatn, Iceland

NASA Astrophysics Data System (ADS)

Black, J. L.; Miller, G. H.; Geirsdottir, A.

2005-12-01

There are no complete records of terrestrial environmental change for the Holocene (11,000yrs) in Iceland and the status of Icelandic glaciers in the early Holocene remains unclear. It is not even known whether Iceland's large ice caps disappeared in the early Holocene, and if they did, when they re-grew. Icelandic lakes are particularly well suited to address these uncertainties as: 1) Glacial erosion and soft bedrock result in high lacustrine sedimentation rates, 2) Diagnostic tephras aid the geochronology, 3) Iceland's sensitivity to changes in North Atlantic circulation should produce clear signals in key environmental proxies (diatoms) preserved in lacustrine sequences, and 4) Ice-cap profiles are relatively flat so small changes in the equilibrium line altitude result in large changes in accumulation area. Hence, large changes in ice-sheet margins during the Holocene will impact sedimentation in glacier-dominated lakes and the diatom assemblages at those times. Hvitarvatn is a glacier dominated lake located on the eastern margin of Langjokull Ice Cap in central-western Iceland. The uppermost Hvitarvatn sediments reflect a glacially dominated system with planktonic, silica-demanding diatom taxa that suggest a high dissolved silica and turbid water environment consistent with high fluxes of glacial flour. Below this are Neoglacial sediments deposited when Langjokull was active, but outlet glaciers were not in contact with Hvitarvatn. The diatom assemblage here shows a small increase in abundance, but is still dominated by planktic, silica-demanding taxa. A distinct shift in lake conditions is reflected in the lowermost sediments, composed of predominantly benthic diatoms and deposited in clear water conditions with long growing seasons likely found in an environment with warmer summers than present and with no glacial erosion. Langjokull must have disappeared in the early Holocene for such a diverse, benthic dominated diatom assemblage to flourish.

Do body weight and gender shape the work force? The case of Iceland.

PubMed

Asgeirsdottir, Tinna Laufey

2011-03-01

Most studies of the relationship between body weight - as well as its corollary, beauty - and labor-market outcomes have indicated that it is a function of a gender bias, the negative relationship between excess weight or obesity and labor-market outcomes being greater for women than for men. Iceland offers an exceptional opportunity to examine this hypothesis, given that it scores relatively well on an index of gender equality comprising economic, political, educational, labor-market, and health-based criteria. Equipped with an advanced level of educational attainment, on average, women are well represented in Iceland's labor force. When it comes to women's presence in the political sphere, Iceland is out of the ordinary as well; that Icelanders were the first in the world to elect a woman to be president may suggest a relatively gender-blind assessment in the labor market. In the current study, survey data collected by Gallup Iceland in 2002 are used to examine the relationship between weight and employment within this political and social setting. Point estimates indicate that, despite apparently lesser gender discrimination in Iceland than elsewhere, the bias against excess weight and obesity remains gender-based, showing a slightly negative relationship between weight and the employment rate of women, whereas a slightly positive relationship was found for men. Copyright © 2010 Elsevier B.V. All rights reserved.

The Icelandic volcanological data node and data service

NASA Astrophysics Data System (ADS)

Vogfjord, Kristin; Sigmundsson, Freysteinn; Futurevolc Team

2013-04-01

Through funding from the European FP7 programme, the International Civil Aviation Authority (ICAO), as well as the local Icelandic government and RANNÍS research fund, the establishment of the Icelandic volcano observatory (VO) as a cross-disciplinary, international volcanological data node and data service is starting to materialize. At the core of this entity is the close collaboration between the Icelandic Meteorological Office (IMO), a natural hazard monitoring and research institution, and researchers at the Earth Science Institute of the University of Iceland, ensuring long-term sustainable access to research quality data and products. Existing Icelandic Earth science monitoring and research infrastructures are being prepared for integration with the European EPOS infrastructure. Because the VO is located at a Met Office, this infrastructure also includes meteorological infrastructures relevant to volcanology. Furthermore, the FP7 supersite project, FUTUREVOLC cuts across disciplines to bring together European researchers from Earth science, atmospheric science, remote sensing and space science focussed on combined processing of the different data sources and results to generate a multiparametric volcano monitoring and early warning system. Integration with atmospheric and space science is to meet the need for better estimates of the volcanic eruption source term and dispersion, which depend not only on the magma flow rate and composition, but also on atmosphere-plume interaction and dispersion. This should lead to better estimates of distribution of ash in the atmosphere. FUTUREVOLC will significantly expand the existing Icelandic EPOS infrastructure to an even more multidisciplinary volcanological infrastructure. A central and sustainable part of the project is the establishment of a research-quality data centre at the VO. This data centre will be able to serve as a volcanological data node within EPOS, making multidisciplinary data accessible to

Comparative analysis of the antioxidant properties of Icelandic and Hawaiian lichens.

PubMed

Hagiwara, Kehau; Wright, Patrick R; Tabandera, Nicole K; Kelman, Dovi; Backofen, Rolf; Ómarsdóttir, Sesselja; Wright, Anthony D

2016-09-01

Antioxidant activity of symbiotic organisms known as lichens is an intriguing field of research because of its strong contribution to their ability to withstand extremes of physical and biological stress (e.g. desiccation, temperature, UV radiation and microbial infection). We present a comparative study on the antioxidant activities of 76 Icelandic and 41 Hawaiian lichen samples assessed employing the DPPH- and FRAP-based antioxidant assays. Utilizing this unprecedented sample size, we show that while highest individual sample activity is present in the Icelandic dataset, the overall antioxidant activity is higher for lichens found in Hawaii. Furthermore, we report that lichens from the genus Peltigera that have been described as strong antioxidant producers in studies on Chinese, Russian and Turkish lichens also show high antioxidant activities in both Icelandic and Hawaiian lichen samples. Finally, we show that opportunistic sampling of lichens in both Iceland and Hawaii will yield high numbers of lichen species that exclusively include green algae as photobiont. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Midwifery in Iceland: From vocational training to university education.

PubMed

Olafsdottir, Olof A; Kristjansdottir, Hildur; Halfdansdottir, Berglind; Gottfredsdottir, Helga

2018-07-01

Midwifery education is a foundation for health professionals' competence in providing quality healthcare for the benefit of women, their families and society. This paper describes midwifery and the development of midwifery education in Iceland. It examines policy and extensive reforms, from hospital-based vocational training in midwifery to an academic university education, and the impact on the scope of midwifery practice in Iceland. The university-based programme, with its emphasis on autonomy of the midwife, seems to have affected the context of home birth and strengthened midwives' role in primary healthcare. Education reform with a focus on evidence-based practice and midwife-led continuity of care has had limited influence within the hospital system, where the structure of care is fragmented and childbirth is under threat of increasing interventions. Research is needed on the role of education in supporting evidence-based practice, normal childbirth and reproductive health in the Icelandic context. Copyright © 2018 Elsevier Ltd. All rights reserved.

Episodic Rifting Events Within the Tjörnes Fracture Zone, an Onshore-Offshore Ridge-Transform in N-Iceland

NASA Astrophysics Data System (ADS)

Brandsdottir, B.; Magnusdottir, S.; Karson, J. A.; Detrick, R. S.; Driscoll, N. W.

2015-12-01

The multi-branched plate boundary across Iceland is made up of divergent and oblique rifts, and transform zones, characterized by entwined extensional and transform tectonics. The Tjörnes Fracture Zone (TFZ), located on the coast and offshore Northern Iceland, is a complex transform linking the northern rift zone (NVZ) on land with the Kolbeinsey Ridge offshore. Extension across TFZ is partitioned across three N-S trending rift basins; Eyjafjarðaráll, Skjálfandadjúp (SB) and Öxarfjörður and three WNW-NW oriented seismic lineaments; the Grímsey Oblique Rift, Húsavík-Flatey Faults (HFFs) and Dalvík Lineament. We compile the tectonic framework of the TFZ ridge-transform from aerial photos, satellite images, multibeam bathymetry and high-resolution seismic reflection data (Chirp). The rift basins are made up of normal faults with vertical displacements of up to 50-60 m, and post-glacial sediments of variable thickness. The SB comprises N5°W obliquely trending, eastward dipping normal faults as well as N10°E striking, westward dipping faults oriented roughly perpendicular to the N104°E spreading direction, indicative of early stages of rifting. Correlation of Chirp reflection data and tephrachronology from a sediment core within SB reveal major rifting episodes between 10-12.1 kyrs BP activating the whole basin, followed by smaller-scale fault movements throughout Holocene. Onshore faults have the same orientations as those mapped offshore and provide a basis for the interpretation of the kinematics of the faults throughout the region. These include transform parallel right-lateral, strike-slip faults separating domains dominated by spreading parallel left-lateral bookshelf faults. Shearing is most prominent along the HFFs, a system of right-lateral strike-slip faults with vertical displacement up to 15 m. Vertical fault movements reflect increased tectonic activity during early postglacial time coinciding with isostatic rebound enhancing volcanism within

NASA Satellite Eyes Iceland Volcano Cauldron

NASA Image and Video Library

2010-04-18

On Saturday, April 17, 2010, NASA Earth Observing-1 EO-1 spacecraft obtained this pair of images of the continuing eruption of Iceland Eyjafjallajökull volcano. On the left, new black ash deposits are visible on the ground.

Recent accelerated warming of the continental shelf off New Jersey: Observations from the CMV Oleander expendable bathythermograph line

NASA Astrophysics Data System (ADS)

Forsyth, Jacob Samuel Tse; Andres, Magdalena; Gawarkiewicz, Glen G.

2015-03-01

Expendable bathythermographs (XBTs) have been launched along a repeat track from New Jersey to Bermuda from the CMV Oleander through the NOAA/NEFSC Ship of Opportunity Program about 14 times per year since 1977. The XBT temperatures on the Middle Atlantic Bight shelf are binned with 10 km horizontal and 5 m vertical resolution to produce monthly, seasonally, and annually averaged cross-shelf temperature sections. The depth-averaged shelf temperature, Ts, calculated from annually averaged sections that are spatially averaged across the shelf, increases at 0.026 ± 0.001°C yr-1 from 1977 to 2013, with the recent trend substantially larger than the overall 37 year trend (0.11 ± 0.02°C yr-1 since 2002). The Oleander temperature sections suggest that the recent acceleration in warming on the shelf is not confined to the surface, but occurs throughout the water column with some contribution from interactions between the shelf and the adjacent Slope Sea reflected in cross-shelf motions of the shelfbreak front. The local warming on the shelf cannot explain the region's amplified rate of sea level rise relative to the global mean. Additionally, Ts exhibits significant interannual variability with the warmest anomalies increasing in intensity over the 37 year record even as the cold anomalies remain relatively uniform throughout the record. Ts anomalies are not correlated with annually averaged coastal sea level anomalies at zero lag. However, positive correlation is found between 2 year lagged Ts anomalies and coastal sea level anomalies, suggesting that the region's sea level anomalies may serve as a predictor of shelf temperature.

[Tablets and tablet production - with special reference to Icelandic conditions].

PubMed

Skaftason, Jóhannes F; Jóhannesson, Thorkell

2013-04-01

Modern tablet compression was instituted in England in 1844 by William Brockedon (1787-1854). The first tablets made according to Brockedon´s procedures contained watersoluble salts and were most likely compressed without expedients. In USA a watershed occurred around 1887 when starch (amylum maydis) was introduced to disperse tablets in aqueous milieu in order to corroborate bioavailability of drugs in the almentary canal. About the same time great advances in tablet production were introduced by the British firm Burroughs Wellcome and Co. In Denmark on the other hand tablet production remained on low scale until after 1920. As Icelandic pharmacies and drug firms modelled themselves mostly upon Danish firms tablet production was first instituted in Iceland around 1930. The first tablet machines in Iceland were hand-driven. More efficent machines came after 1945. Around 1960 three sizeable tablet producers were in Iceland; now there is only one. Numbers of individual tablet species (generic and proprietary) on the market rose from less than 10 in 1913 to 500 in 1965, with wide variations in numbers in between. Tablets have not wiped out other medicinal forms for peroral use but most new peroral drugs have been marketed in the form of tablets during the last decades.

Influence of consonant frequency on Icelandic-speaking children's speech acquisition.

PubMed

Másdóttir, Thóra; Stokes, Stephanie F

2016-04-01

A developmental hierarchy of phonetic feature complexity has been proposed, suggesting that later emerging sounds have greater articulatory complexity than those learned earlier. The aim of this research was to explore this hierarchy in a relatively unexplored language, Icelandic. Twenty-eight typically-developing Icelandic-speaking children were tested at 2;4 and 3;4 years. Word-initial and word-medial phonemic inventories and a phonemic implicational hierarchy are described. The frequency of occurrence of Icelandic consonants in the speech of 2;4 and 3;4 year old children was, from most to least frequent, n, s, t, p, r, m, l, k, f, ʋ, j, ɵ, h, kʰ, c, [Formula: see text], ɰ, pʰ, tʰ, cʰ, ç, [Formula: see text], [Formula: see text], [Formula: see text]. Consonant frequency was a strong predictor of consonant accuracy at 2;4 months (r(23) = -0.75), but the effect was weaker at 3;4 months (r(23) = -0.51). Acquisition of /c/, /[Formula: see text]/ and /l/ occurred earlier, relative to English, Swedish, Dutch and German. A frequency-bound practice effect on emerging consonants is proposed to account for the early emergence of /c/, /[Formula: see text]/ and /l/ in Icelandic.

The life of family trees and the Book of Icelanders.

PubMed

Pálsson, Gísli

2002-01-01

This article discusses the tracing of family histories and competing assumptions about identities and relatedness in the era of biotechnology and biopower. Although the fascination with genealogical trees and family histories is common throughout the West, in Iceland this attraction is extreme. A genealogical database for most of the Icelandic population, the so-called Book of Icelanders, is being constructed as part of a larger biogenetic enterprise that seeks to establish the presumed genetic causes of common diseases for the purpose of developing pharmaceutical products. The discussion explores the changing implications of family trees as they become enmeshed in biomedical projects and political debates. Genealogical records, I suggest, are never innocent phenomena; this is because they have a social life of their own, a biography informed by the contours of the cultural landscapes to which they belong.

Iceland as the largest source of natural air pollution in the Arctic

NASA Astrophysics Data System (ADS)

Dagsson Waldhauserova, Pavla; Meinander, Outi; Olafsson, Haraldur; Arnalds, Olafur

2017-04-01

Arctic aerosols are often attributed to the Arctic Haze and long-range transport tracers. There is, however, an important dust source in the Arctic/Sub-arctic region which should receive more attention. The largest desert in the Arctic as well as in the Europe is Iceland with > 40,000 km2 of desert areas. The mean dust suspension frequency was 135 dust days annually in 1949-2012 with decreasing numbers in 2013-2015. The annual dust deposition was calculated as 31-40 million tons yr-1 affecting the area of > 500,000 km2. Satelite MODIS pictures have revealed dust plumes traveling > 1000 km at times. The physical properties of Icelandic dust showed differences in mineralogy, geochemical compositions, shapes, sizes, and colour, compared to the crustal mineral dust. Icelandic dust is of volcanic origin, dark in colour with sharp-tipped shards and large bubbles. About 80% of the particulate matter is volcanic glass rich in heavy metals, such as iron and titanium. Suspended dust measured at the glacial dust source consisted of such high number of close-to-ultrafine particles as concentrations during active eruptions. Generally, about 50% of the suspended PM10 are submicron particles in Iceland. Contrarily, suspended grains > 2 mm were captured during severe dust storm after the 2010 Eyjafjallajokull eruption when the aeolian transport exceeded 11 t m-1 of materials and placed this storms among the most extreme wind erosion events recorded on Earth. Our reflectance measurements showed that Icelandic dust deposited on snow lowers the snow albedo and reduces the snow density as much as Black Carbon. Icelandic volcanic dust tends to act as a positive climate forcing agent, both directly and indirectly, which is different to what generally concluded for crustal dust in the 2013 IPCC report. The high frequency, severity and year-round activity of volcanic dust emissions suggest that Icelandic dust may contribute to Arctic warming.

Crustal Structure of the Iceland Region from Spectrally Correlated Free-air and Terrain Gravity Data

NASA Technical Reports Server (NTRS)

Leftwich, T. E.; vonFrese, R. R. B.; Potts, L. V.; Roman, D. R.; Taylor, P. T.

2003-01-01

Seismic refraction studies have provided critical, but spatially restricted constraints on the structure of the Icelandic crust. To obtain a more comprehensive regional view of this tectonically complicated area, we spectrally correlated free-air gravity anomalies against computed gravity effects of the terrain for a crustal thickness model that also conforms to regional seismic and thermal constraints. Our regional crustal thickness estimates suggest thickened crust extends up to 500 km on either side of the Greenland-Scotland Ridge with the Iceland-Faeroe Ridge crust being less extended and on average 3-5 km thinner than the crust of the Greenland-Iceland Ridge. Crustal thickness estimates for Iceland range from 25-35 km in conformity with seismic predictions of a cooler, thicker crust. However, the deepening of our gravity-inferred Moho relative to seismic estimates at the thermal plume and rift zones of Iceland suggests partial melting. The amount of partial melting may range from about 8% beneath the rift zones to perhaps 20% above the plume core where mantle temperatures may be 200-400 C above normal. Beneath Iceland, areally limited regions of partial melting may also be compositionally and mechanically layered and intruded. The mantle plume appears to be centered at (64.6 deg N, 17.4 deg W) near the Vatnajokull Glacier and the central Icelandic neovolcanic zones.

The triggering factors of the Móafellshyrna debris slide in northern Iceland: Intense precipitation, earthquake activity and thawing of mountain permafrost.

PubMed

Sæmundsson, Þorsteinn; Morino, Costanza; Helgason, Jón Kristinn; Conway, Susan J; Pétursson, Halldór G

2018-04-15

On the 20th September 2012, a large debris slide occurred in the Móafellshyrna Mountain in the Tröllaskagi peninsula, central north Iceland. Our work describes and discusses the relative importance of the three factors that may have contributed to the failure of the slope: intense precipitation, earthquake activity and thawing of ground ice. We use data from weather stations, seismometers, witness reports and field observations to examine these factors. The slide initiated after an unusually warm and dry summer followed by a month of heavy precipitation. Furthermore, the slide occurred after three seismic episodes, whose epicentres were located ~60km NNE of Móafellshyrna Mountain. The main source of material for the slide was ice-rich colluvium perched on a topographic bench. Blocks of ice-cemented colluvium slid and then broke off the frontal part of the talus slope, and the landslide also involved a component of debris slide, which mobilized around 312,000-480,000m 3 (as estimated from field data and aerial images of erosional morphologies). From our analysis we infer that intense precipitation and seismic activity prior to the slide are the main preparatory factors for the slide. The presence of ice-cemented blocks in the slide's deposits leads us to infer that deep thawing of ground ice was likely the final triggering factor. Ice-cemented blocks of debris have been observed in the deposits of two other recent landslides in northern Iceland, in the Torfufell Mountain and the Árnesfjall Mountain. This suggests that discontinuous mountain permafrost is degrading in Iceland, consistent with the decadal trend of increasing atmospheric temperature in Iceland. This study highlights a newly identified hazard in Iceland: landslides as a result of ground ice thaw. Knowledge of the detailed distribution of mountain permafrost in colluvium on the island is poorly constrained and should be a priority for future research in order to identify zones at risk from this

Glacial Boundary Features Delineated Using Enhanced-resolution Passive-microwave Data to Determine Melt Season Variation of the Vatnajokull Ice Cap, Iceland

NASA Astrophysics Data System (ADS)

Marzillier, D. M.; Ramage, J. M.

2017-12-01

Temperate glaciers such as those seen in Iceland experience high annual mass flux, thereby responding to small scale changes in Earth's climate. Decadal changes in the glacial margins of Iceland's ice caps are observable in the Landsat record, however twice daily AMSR-E Calibrated Enhanced-Resolution Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature (CETB) Earth System Data Record (ESDR) allow for observation on a daily temporal scale and a 3.125 km spatial scale, which can in turn be connected to patterns seen over longer periods of time. Passive microwave data allow for careful observation of melt onset and duration in Iceland's glacial regions by recording changes in emissivity of the ice surface, known as brightness temperature (TB), which is sensitive to fluctuations in the liquid water content of snow and ice seen during melting in glaciated regions. Enhanced resolution of this data set allows for a determination of a threshold that defines the melting season. The XPGR snowmelt algorithm originally presented by Abdalati and Steffen (1995) is used as a comparison with the diurnal amplitude variation (DAV) values on Iceland's Vatnajokull ice cap located at 64.4N, -16.8W. Ground-based air temperature data in this region, digital elevation models (DEMs), and river discharge dominated by glacial runoff are used to confirm the glacial response to changes in global climate. Results show that Iceland glaciers have a bimodal distribution of brightness temperature delineating when the snow/ice is melting and refreezing. Ground based temperatures have increased on a decadal trend. Clear glacial boundaries are visible on the passive microwave delineating strong features, and we are working to understand their variability and contribution to glacier evolution. The passive microwave data set allows connections to be made between observations seen on a daily scale and the long term glacier changes observed by the Landsat satellite record that integrates the

Progress report on research on human genetics in Iceland

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1980-10-31

Records of the Icelandic population are being used to investigate the possible inheritance of disabilities and diseases as well as other characteristics and the effect of environment on man. The progress report of research covers the period from 1977 to 1980. The investigation was begun in 1965 by the Genetical Committee of the University of Iceland and the materials used are demographic records from the year 1840 to present and various medical information. The records are being computerized and linked together to make them effective for use in hereditary studies.

Phytoplankton bloom off Iceland

NASA Image and Video Library

2014-08-13

A massive phytoplankton bloom stained the waters of the Atlantic Ocean north of Iceland with brilliant jewel tones in late summer, 2014. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image on August 2. Huge colonies of the floating, plant-like organisms create swirls of green, teal and turquoise and cover over 80% of the visible ocean off the northeast coast of Iceland. Marine phytoplankton require just the right amount of sunlight, dissolved nutrients and water temperatures which are not too hot, nor too cold to spark explosive reproduction and result in blooms which can cover hundreds of square kilometers. Phytoplankton form the base of the marine food chain, and are a rich food source for zooplankton, fish and other marine species. Some species, however, can deplete the water of oxygen and may become toxic to marine life. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team 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

Biological, physical and chemical properties at the Subtropical Shelf Front Zone in the SW Atlantic Continental Shelf

NASA Astrophysics Data System (ADS)

Muelbert, José H.; Acha, Marcelo; Mianzan, Hermes; Guerrero, Raúl; Reta, Raúl; Braga, Elisabete S.; Garcia, Virginia M. T.; Berasategui, Alejandro; Gomez-Erache, Mónica; Ramírez, Fernando

2008-07-01

The physical aspects of the Subtropical Shelf Front (STSF) for the Southwest Atlantic Continental Shelf were previously described. However, only scarce data on the biology of the front is available in the literature. The main goal of this paper is to describe the physical, chemical and biological properties of the STSF found in winter 2003 and summer 2004. A cross-section was established at the historically determined location of the STSF. Nine stations were sampled in winter and seven in summer. Each section included a series of conductivity-temperature-depth (CTD) stations where water samples from selected depths were filtered for nutrient determination. Surface samples were taken for chlorophyll a (Chl- a) determination and plankton net tows carried out above and below the pycnocline. Results revealed that winter was marked by an inner-shelf salinity front and that the STSF was located on the mid-shelf. The low salinity waters in the inner-shelf indicated a strong influence of freshwater, with high silicate (72 μM), suspended matter (45 mg l -1), phosphate (2.70 μM) and low nitrate (1.0 μM) levels. Total dissolved nitrogen was relatively high (22.98 μM), probably due to the elevated levels of organic compound contribution close to the continental margin. Surface Chl -a concentration decreased from coastal well-mixed waters, where values up to 8.0 mg m -3 were registered, to offshore waters. Towards the open ocean, high subsurface nutrients values were observed, probably associated to South Atlantic Central Waters (SACW). Zooplankton and ichthyoplankton abundance followed the same trend; three different groups associated to the inner-, mid- and outer-shelf region were identified. During summer, diluted waters extended over the shelf to join the STSF in the upper layer; the concentration of inorganic nutrients decreased in shallow waters; however, high values were observed between 40 and 60 m and in deep offshore waters. Surface Chl -a ranged 0.07-1.5 mg m -3

The elimination of echinococcosis from Iceland

PubMed Central

Beard, Trevor C.

1973-01-01

A century ago Iceland had the highest prevalence of human hydatid disease ever recorded anywhere. Since 1864 the disease has been gradually controlled, and today there is less than one new case per decade. The sheep population of about one million, over 95% of which is subject to inspection at slaughter, has yielded only 15 infected animals in the last 20 years. In most districts farm slaughtering still persists, though on a very limited scale, and farm dogs are subjected to very little control. The main credit for the remarkable control of E. granulosus is given to education, but many accidental social and environmental factors, peculiar to Iceland, contributed to the result. Of these, the most notable were the small human population and high rate of literacy; the very high dog mortality from distemper in the 19th century, which coincided with a major export trade in live sheep; the custom of feeding dogs on cooked household scraps, the risk of infection being confined to the short sheep slaughtering season and the rare occasions when a cow or pig is slaughtered; the absence of employed labour on Icelandic farms, all slaughtering being done by the owner, an educated man with middle-class values; the change in animal husbandry since 1920 towards the slaughter of 5-month-old lambs, too young to have viable cysts; and the meat subsidy, which since 1947 has led to the use of abattoirs for all but a handful of uneconomic animals kept for slaughter on the farm. PMID:4544777

Crustal Structure of the Iceland Region from Spectrally Correlated Free-air and Terrain Gravity Data

NASA Technical Reports Server (NTRS)

Leftwich, T. E.; vonFrese, R. R. R. B.; Potts, L. V.; Roman, D. R.; Taylor, Patrick T.

2003-01-01

Seismic refraction studies have provided critical, but spatially restricted constraints on the structure of the Icelandic crust. To obtain a more comprehensive regional view of this tectonically complicated area, we spectrally correlated free-air gravity anomalies against computed gravity effects of the terrain for a crustal thickness model that also conforms to regional seismic and thermal constraints. Our regional crustal thickness estimates suggest thickened crust extends up to 500 km on either side of the Greenland-Scotland Ridge with the Iceland-Faeroe Ridge crust being less extended and on average 3-5 km thinner than the crust of the Greenland-Iceland Ridge. Crustal thickness estimates for Iceland range from 25-35 km in conformity with seismic predictions of a cooler, thicker crust. However, the deepening of our gravity-inferred Moho relative to seismic estimates at the thermal plume and rift zones of Iceland suggests partial melting. The amount of partial melting may range from about 8% beneath the rift zones to perhaps 20% above the plume core where mantle temperatures may be 200-400 C above normal. Beneath Iceland, areally limited regions of partial melting may also be compositionally and mechanically layered

Surging glaciers in Iceland - research status and future challenges

NASA Astrophysics Data System (ADS)

Ingolfsson, Olafur

2013-04-01

Twenty six Icelandic outlet glaciers, ranging from 0.5-1.500 km2, are known to surge, with terminal advances ranging from of few tens of meters to about 10 km. The geomorphic signatures of surges vary, from large-scale folded and thrusted end moraine systems, extensive dead-ice fields and drumlinized forefields to drift sheets where fast ice-flow indicators are largely missing. Case studies from the forefields of Brúarjökull, Eyjabakkajökull and Múlajökull surging glaciers will be presented. At Brúarjökull, extremely rapid ice flow during surge was sustained by overpressurized water causing decoupling beneath a thick sediment sequence that was coupled to the glacier. The ice-marginal position of the 1890 surge is marked by a sedimentary wedge formed within five days and a large moraine ridge that formed in about one day ("instantaneous end-moraine"). Three different qualitative and conceptual models are required to explain the genesis of the Eyjabakkajökull moraines: a narrow, single-crested moraine ridge at the distal end of a marginal sediment wedge formed in response to decoupling of the subglacial sediment from the bedrock and associated downglacier sediment transport; large lobate end moraine ridges with multiple, closely spaced, asymmetric crests formed by proglacial piggy-back thrusting; moraine ridges with different morphologies may reflect different members of an end moraine continuum. A parallel study highlighting the surge history of Eyjabakkajökull over the last 4400 years suggests climate control on surge frequencies. The Múlajökull studies concern an active drumlin field (>100 drumlins) that is being exposed as the glacier retreats. The drumlins form through repeated surges, where each surge causes deposition of till bed onto the drumlin while similtaneously eroding the sides. Finally, a new landsystem model for surging North Iceland cirque glaciers will be introduced. References Benediktsson,I. Ö., Schomacker, A., Lokrantz, H. & Ing

Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica.

PubMed

Cochran, James R; Tinto, Kirsty J; Bell, Robin E

2015-05-01

Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β , of 1.5-1.7 with 80-100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise.

Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

PubMed Central

Cochran, James R; Tinto, Kirsty J; Bell, Robin E

2015-01-01

Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5–1.7 with 80–100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. Key Points: Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise PMID:26709352

Comparison of grass haylage digestibility and metabolic plasma profile in Icelandic and Standardbred horses.

PubMed

Ragnarsson, S; Jansson, A

2011-06-01

The aim of the present study was to compare digestibility and metabolic response in Icelandic and Standardbred horses fed two grass haylages harvested at different stages of maturity. Six horses of each breed were used in a 24-day change-over design. A total collection of faeces was made on days 15-17 and 22-24. Blood samples were collected on day 24 of each period and analysed for total plasma protein (TPP), plasma urea, non-esterified fatty acids, cortisol and insulin concentration. There were no differences in digestibility coefficients of crude protein, neutral detergent fibre or energy between breeds but organic matter digestibility was higher in the Standardbred horses. On both haylages, the Icelandic horses gained weight whereas the Standardbred horses lost weight. The Icelandic horses had higher TPP, plasma insulin and lower plasma urea concentrations. Our results indicate that the Icelandic horse may be more prone to maintain positive energy balance in relation to the Standardbred horse, but there were no indication of a better digestive capacity in the Icelandic horses. © 2010 Blackwell Verlag GmbH.

Aeolian transport of Icelandic dust: a look from Space

NASA Astrophysics Data System (ADS)

Smejda, Ladislav; Dagsson Waldhauserova, Pavla; Hejcman, Michal

2017-04-01

Iceland represents a unique type of Arctic environment where glaciers capture the precipitation, consequently forming large deserts on the leeward side. Deserts are subject to strong winds and dust is reported to be suspended at least 135 days a year. Icelandic dust has seven major dust sources in extensive deserts, consisting mainly of volcanic glass. In this paper, we address a new approach to the question of the island's contribution to atmospheric dust transport in the North Atlantic and Arctic Oceans. We explore the strengths and limitations of satellite imagery for the study of high altitude dust storm phenomenon, and more specifically the potential of freely available set of tools for remote sensing and spatial data analysis, the Earth Engine provided by Google. This cloud-based geospatial processing platform requires only a web browser on the side of a user, and it allows writing powerful and versatile algorithms for scientific analysis of spatial data. We demonstrate how this approach can be applied to mapping of Icelandic dust sources and studying the wind erosion and transport of particles in the atmosphere in high latitudes.

The origin of shear wave splitting beneath Iceland

NASA Astrophysics Data System (ADS)

Ito, Garrett; Dunn, Robert; Li, Aibing

2015-06-01

The origin of shear wave splitting (SWS) in the mantle beneath Iceland is examined using numerical models that simulate 3-D mantle flow and the development of seismic anisotropy due to lattice-preferred orientation (LPO). Using the simulated anisotropy structure, we compute synthetic SKS waveforms, invert them for fast polarization directions and split times, and then compare the predictions with the results from three observational studies of Iceland. Models that simulate a mantle plume interacting with the Mid-Atlantic Ridge in which the shallow-most mantle has a high viscosity due to the extraction of water with partial melting, or in which C-type olivine LPO fabric is present due to high water content in the plume, produce the largest chi-squared misfits to the SWS observations and are thus rejected. Models of a low-viscosity mantle plume with A-type olivine fabric everywhere, or with the added effects of E-type fabric in the plume below the solidus produce lower misfits. The lowest misfits are produced by models that include a rapid (˜50 km Myr-1) northward regional flow (NRF) in the mid-upper mantle, either with or without a plume. NRF was previously indicated by a receiver function study and a regional tomography study, and is shown here to be a major cause of the azimuthal anisotropy beneath Iceland. The smallest misfits for the models with both a plume and NRF are produced when LPO forms above depths of 300-400 km, which, by implication, also mark the depths above which dislocation creep dominates over diffusion creep. This depth of transition between dislocation and diffusion creep is greater than expected beneath normal oceanic seafloor, and is attributed to the unusually rapid strain rates associated with an Iceland plume and the NRF.

Educational Leadership and Market Values: A Study of School Principals in Iceland

ERIC Educational Resources Information Center

Lárusdóttir, Steinunn Helga

2014-01-01

This article reports on the findings of a larger case study about the impact of values on educational leaders in Iceland. The environment of Icelandic schools has changed considerably in recent years. These changes have affected schools and changed the nature and scope of principals' work. Scholars have argued that these changes are primarily…

Maximizing industrial infrastructure efficiency in Iceland

NASA Astrophysics Data System (ADS)

Ingason, Helgi Thor; Sigfusson, Thorsteinn I.

2010-08-01

As a consequence of the increasing aluminum production in Iceland, local processing of aluminum skimmings has become a feasible business opportunity. A recycling plant for this purpose was built in Helguvik on the Reykjanes peninsula in 2003. The case of the recycling plant reflects increased concern regarding environmental aspects of the industry. An interesting characteristic of this plant is the fact that it is run in the same facilities as a large fishmeal production installation. It is operated by the same personnel and uses—partly—the same equipment and infrastructure. This paper reviews the grounds for these decisions and the experience of this merger of a traditional fish melting industry and a more recent aluminum melting industry after 6 years of operation. The paper is written by the original entrepreneurs behind the company, who provide observations on how the aluminum industry in Iceland has evolved since the starting of Alur’s operation and what might be expected in the near future.

Pliocene shallow water paleoceanography of the North Atlantic ocean based on marine ostracodes

USGS Publications Warehouse

Cronin, T. M.

1991-01-01

Middle Pliocene marine ostracodes from coastal and shelf deposits of North and Central America and Iceland were studied to reconstruct paleotemperatures of shelf waters bordering portions of the Western Boundary Current System (including the Gulf Loop Current, Florida Current, Gulf Stream and North Atlantic Drift). Factor analytic transfer functions provided Pliocene August and February bottom-water temperatures of eight regions from the tropics to the subfrigid. The results indicate: (1) meridional temperature gradients in the western North Atlantic were less steep during the Pliocene than either today or during Late Pleistocene Isotope Stage 5e; (2) tropical and subtropical shelf waters during the Middle Pliocene were as warm as, or slightly cooler than today; (3) slightly cooler water was on the outer shelf off the southeastern and mid-Atlantic coast of the U.S., possibly due to summer upwelling of Gulf Stream water; (4) the shelf north of Cape Hatteras, North Carolina may have been influenced by warm water incursions from the western edge of the Gulf Stream, especially in summer; (5) the northeast branch of the North Atlantic Drift brought warm water to northern Iceland between 4 and 3 Ma; evidence from the Iceland record indicates that cold East Greenland Current water did not affect coastal Iceland between 4 and 3 Ma; (6) Middle Pliocene North Atlantic circulation may have been intensified, transporting more heat from the tropics to the Arctic than it does today. ?? 1991.

Cost-effectiveness of human papilloma virus vaccination in Iceland.

PubMed

Oddsson, Kristjan; Johannsson, Jakob; Asgeirsdottir, Tinna Laufey; Gudnason, Thorolfur

2009-01-01

To evaluate the likely cost-effectiveness of introducing routine HPV vaccination in Iceland. Prospective cost-effectiveness analysis of human papilloma virus (HPV) vaccination. Population of 12-year-old girls in the Icelandic population. A model was developed, comparing a cohort of all 12-year-old girls alive in year 2006, with or without vaccination. The model was based on the epidemiology of cervical cancer in Iceland and its premalignant stages as well as the costs involved in the treatment of each stage, assuming that the vaccines only prevent infections caused by HPV 16/18 at an efficacy of 95% and participation rate of 90%, no catch-up vaccination, no vaccination of boys and no booster dose needed. All costs were calculated on the basis of the price level of mid-year 2006 with a 3% discount rate. Incremental cost-effectiveness ratio calculations were performed and sensitivity analysis was carried out on factors most relevant for cost-effectiveness. Vaccination costs in excess of savings would be about euro313.000/year. Vaccination would reduce the number of women diagnosed with cervical cancer by almost 9, prevent the death of 1.7 women and result in 16.9 quality-adjusted life years gained annually. The incremental cost-effectiveness ratio was calculated to be about euro18.500/quality-adjusted life year saved. HPV vaccination seems to be cost-effective in Iceland, but this was sensitive to various parameters in the model, mainly the discount rate, the price of the vaccines and the need for a booster dose.

Religion, modernity and foreign nurses in Iceland 1896-1930.

PubMed

Björnsdóttir, Kristin; Malchau, Susanne

2004-09-01

This paper describes the influence of foreign nurses upon the development of modern healthcare services and the nursing profession in Iceland in the first three decades of the twentieth century. It represents a case study of how new ideas, traditions and practices migrated between countries and cultures in the twentieth century. Icelandic society was, at that time, still premodern in many ways. Healthcare institutions were almost nonexistent and the means of production were undeveloped. It was into this context that the idea of nursing as a professional activity was introduced. Groups of nurses, the Catholic Sisters of St Joseph of Chambéry and secular nurses, mainly from Denmark, came to the country to organize and provide healthcare services, of which nursing was of central importance. These groups were diasporas, in that they brought traditions and practices from other cultures. The Sisters of St Joseph built, owned and ran the first modern hospital in the country. The Danish nurses introduced nursing as a specialized field of work, in leprosy and tuberculosis nursing and by initiating public health nursing services. They were instrumental in promoting education as an important condition to becoming a nurse, and the development of an Icelandic nursing profession. These nurses were generally respected by the Icelandic people for their contributions and were received with interest and appreciation. The healthcare services introduced by these different groups of nurses reflected modern ways of living and a commitment to professionalism, which involved providing assistance to patients based on the best knowledge available and a philosophy of respect and care.

Icelandic geothermal activity and the mercury of the Greenland icecap.

NASA Technical Reports Server (NTRS)

Siegel, B. Z.; Siegel, S. M.; Thorarinsson, F.

1973-01-01

Aerometric studies concerning the level of atmospheric mercury were conducted at a number of sites in Iceland during June and July 1972. Samples from widely separated locations yielded Hg concentrations well above the range commonly cited for unpolluted air. Atmospheric mercury may be introduced in part by degassing fluid magmas. However, the release from fine ash could also serve as a vehicle. It is pointed out that from the mid-17th century to the present, Iceland has recorded nearly 50 volcanic eruptions.

Development of Indigenous Basic Interest Scales: Re-Structuring the Icelandic Interest Space

ERIC Educational Resources Information Center

Einarsdottir, Sif; Eyjolfsdottir, Katrin Osk; Rounds, James

2013-01-01

The present investigation used an emic approach to develop a set of Icelandic indigenous basic interest scales. An indigenous item pool that is representative of the Icelandic labor market was administered to three samples (N = 1043, 1368, and 2218) of upper secondary and higher education students in two studies. A series of item level cluster and…

North Atlantic Oscillation modulates total ozone winter trends

NASA Astrophysics Data System (ADS)

Appenzeller, Christof; Weiss, Andrea K.; Staehelin, Johannes

2000-04-01

The North Atlantic Oscillation (NAO) is modulating the Earth's ozone shield such that the calculated anthropogenic total ozone decrease is enhanced over Europe whereas over the North Atlantic region it is reduced (for the last 30 years). Including the NAO in a statistical model suggests a more uniform chemical winter trend compared to the strong longitudinal variation reported earlier. At Arosa (Switzerland) the trend is reduced to -2.4% per decade compared to -3.2% and at Reykjavik (Iceland) it is enhanced to -3.8% compared to 0%. The revised trend is slightly below the predictions by 2D chemical models. Decadal ozone variability is linked to variations in the dynamical structure of the atmosphere, as reflected in the tropopause pressure. The latter varies in concert with the NAO index with a distinct geographical pattern.

Soot on snow in Iceland: First results on black carbon and organic carbon in Iceland 2016 snow and ice samples, including the glacier Solheimajökull

NASA Astrophysics Data System (ADS)

Meinander, Outi; Dagsson-Waldhauserova, Pavla; Gritsevich, Maria; Aurela, Minna; Arnalds, Olafur; Dragosics, Monika; Virkkula, Aki; Svensson, Jonas; Peltoniemi, Jouni; Kontu, Anna; Kivekäs, Niku; Leppäranta, Matti; de Leeuw, Gerrit; Laaksonen, Ari; Lihavainen, Heikki; Arslan, Ali N.; Paatero, Jussi

2017-04-01

New results on black carbon (BC) and organic carbon (OC) on snow and ice in Iceland in 2016 will be presented in connection to our earlier results on BC and OC on Arctic seasonal snow surface, and in connection to our 2013 and 2016 experiments on effects of light absorbing impurities, including Icelandic dust, on snow albedo, melt and density. Our sampling included the glacier Solheimajökull in Iceland. The mass balance of this glacier is negative and it has been shrinking during the last 20 years by 900 meters from its southwestern corner. Icelandic snow and ice samples were not expected to contain high concentrations of BC, as power generation with domestic renewable water and geothermal power energy sources cover 80 % of the total energy consumption in Iceland. Our BC results on filters analyzed with a Thermal/Optical Carbon Aerosol Analyzer (OC/EC) confirm this assumption. Other potential soot sources in Iceland include agricultural burning, industry (aluminum and ferroalloy production and fishing industry), open burning, residential heating and transport (shipping, road traffic, aviation). On the contrary to low BC, we have found high concentrations of organic carbon in our Iceland 2016 samples. Some of the possible reasons for those will be discussed in this presentation. Earlier, we have measured and reported unexpectedly low snow albedo values of Arctic seasonally melting snow in Sodankylä, north of Arctic Circle. Our low albedo results of melting snow have been confirmed by three independent data sets. We have explained these low values to be due to: (i) large snow grain sizes up to 3 mm in diameter (seasonally melting snow); (ii) meltwater surrounding the grains and increasing the effective grain size; (iii) absorption caused by impurities in the snow, with concentration of elemental carbon (black carbon) in snow of 87 ppb, and organic carbon 2894 ppb. The high concentrations of carbon were due to air masses originating from the Kola Peninsula, Russia

The Adult Reading History Questionnaire (ARHQ) in Icelandic: Psychometric Properties and Factor Structure

ERIC Educational Resources Information Center

Bjornsdottir, Gyda; Halldorsson, Jonas G.; Steinberg, Stacy; Hansdottir, Ingunn; Kristjansson, Kristleifur; Stefansson, Hreinn; Stefansson, Kari

2014-01-01

This article describes psychometric testing of an Icelandic adaptation of the "Adult Reading History Questionnaire" (ARHQ), designed to detect a history of reading difficulties indicative of dyslexia. Tested in a large and diverse sample of 2,187 adults, the Icelandic adaptation demonstrated internal consistency reliability (Cronbach's…

The triggering factors of the Móafellshyrna debris slide in northern Iceland: intense precipitation, earthquake activity and thawing of mountain permafrost

NASA Astrophysics Data System (ADS)

Saemundsson, Thorsteinn; Morino, Costanza; Kristinn Helgason, Jón; Conway, Susan J.; Pétursson, Halldór G.

2017-04-01

On the 20th of September in 2012, a large debris slide occurred in the Móafellshyrna Mountain in the Tröllaskagi peninsula, central north Iceland. Three factors are likely to have contributed to the failure of the slope: intense precipitation, earthquake activity and thawing of ground ice. The weather conditions prior the slide were somewhat unusual, with a warm and dry summer. From the 20th of August to the 20th of September, about 440 mm of precipitation fell in the area, where the mean annual precipitation at the nearest station is around 670 mm. The slide initiated after this thirty day period of intense precipitation, followed by a seismic sequence in the Eyjafjarðaráll graben, located about 60 km NNE of Móafellshyrna Mountain, a sequence that started on the 19th of September. The slide originated at elevation of 870 m a.s.l. on the NW-slope of the mountain. The total volume of the debris slide is estimated around 500,000 m3 and that its primary cause was intense precipitation. We cannot exclude the influence of the seismic sequence as a secondary contributing factor. The presence of ice-cemented blocks of talus immediately after the debris slide shows that thawing of ground ice could also have played an important role as a triggering factor. Ice-cemented blocks of talus have been observed in the deposits of two other recent landslides in northern Iceland, in the Torfufell Mountain and the Árnesfjall Mountain. The source areas for both the Móafellshyrna and the Torfufell slides are within the lower elevation limit of mountain permafrost in northern Iceland but the source area of the Árnesfjall slide is at much lower elevation, around 350 m a.s.l. The fact that there are now three documented landslides which are linked to ground ice-melting suggests that discontinuous permafrost is degrading in Iceland, consistent with the decadal trend of increasing atmospheric temperature in Iceland due to climate change. This study highlights that ground ice thaw

mtDNA and the Origin of the Icelanders: Deciphering Signals of Recent Population History

PubMed Central

Helgason, Agnar; Sigurðardóttir, Sigrún; Gulcher, Jeffrey R.; Ward, Ryk; Stefánsson, Kári

2000-01-01

Previous attempts to investigate the origin of the Icelanders have provided estimates of ancestry ranging from a 98% British Isles contribution to an 86% Scandinavian contribution. We generated mitochondrial sequence data for 401 Icelandic individuals and compared these data with >2,500 other European sequences from published sources, to determine the probable origins of women who contributed to Iceland’s settlement. Although the mean number of base-pair differences is high in the Icelandic sequences and they are widely distributed in the overall European mtDNA phylogeny, we find a smaller number of distinct mitochondrial lineages, compared with most other European populations. The frequencies of a number of mtDNA lineages in the Icelanders deviate noticeably from those in neighboring populations, suggesting that founder effects and genetic drift may have had a considerable influence on the Icelandic gene pool. This is in accordance with available demographic evidence about Icelandic population history. A comparison with published mtDNA lineages from European populations indicates that, whereas most founding females probably originated from Scandinavia and the British Isles, lesser contributions from other populations may also have taken place. We present a highly resolved phylogenetic network for the Icelandic data, identifying a number of previously unreported mtDNA lineage clusters and providing a detailed depiction of the evolutionary relationships between European mtDNA clusters. Our findings indicate that European populations contain a large number of closely related mitochondrial lineages, many of which have not yet been sampled in the current comparative data set. Consequently, substantial increases in sample sizes that use mtDNA data will be needed to obtain valid estimates of the diverse ancestral mixtures that ultimately gave rise to contemporary populations. PMID:10712214

[Scientific articles in the Icelandic Medical Journal 2004-2008: an overview].

PubMed

Gudbjartsson, Tómas; Sigurdsson, Engilbert

2009-10-01

In the past 5 years the Icelandic Medical Journal has undergone many changes during a period of flourishing research in Iceland. The process of reviewing and editing scientific articles has been revised since the Journal joined the Medline database in 2005 and the proportion of rejected articles has risen. New columns have been launched covering medical history, professionalism, ethics and hobbies of the medical profession. We categorized all scientific articles from the period 2004-2008, that is research articles, review articles, case reports and clinical guidelines, according to types of articles and to which medical speciality or subspeciality the publication should belong. The number of scientific articles rose during the period but the number of research articles remained around 20 most years during the period. The relative proportion of research articles therefore fell whereas the number and proportion of review articles and case reports increased. Clinical guidelines ceased to appear in the Journal. The contribution of individual specialities to the Journal varied widely. Researchers amongst doctors and related professions need be encouraged to submit scientific articles to the Journal. The publication of scientific articles in English in the web-based form of the Journal may prove to be stimulating in this regard for Icelandic doctors abroad as well as for some researchers in Iceland.

Fracture analysis near the mid-ocean plate boundary, Reykjavik-Hvalfjördur area, Iceland

NASA Astrophysics Data System (ADS)

Jefferis, Robert G.; Voight, Barry

1981-07-01

The geometry and thermal history of fractures have been determined at 59 stations from Reykjavik to Hvalfjördur in southwestern Iceland. The data provide information on crustal stress regimes in the vicinity of mid-ocean ridges. Two major, generalized fracture orientations are present (1) a northeast system, trend 010°-030°, except on Akranes where the orientation is 040°-060° (2) a broad east—west system containing one or more sets with strike between 070°-130°. Thermal history of the host rock and fractures was determined from secondary minerals in vugs and fractures. The thermal history indicates that the northeast fracture set opened while the area was within the relatively hot axial zone of active volcanism and rifting. Some of the east—west trending fractures also opened at this time but many formed later, after the area had begun to cool and drift from the active zone. The northeast fracture set is essentially parallel to the trend of dikes and normal faults in southwestern Iceland. They have been interpreted as extension fractures (resulting in about 0.4% maximum extension) forming generally from the same stress field associated with normal faulting and dike injection in the active zone. Fracturing in an east-west direction (estimated 0.1% maximum extension), mainly near the edge and outside the active zone, indicates a reorientation of this stress field. The dominant mechanism related to the origin of the east—west fractures may be thermoelastic stresses arising from axial and basal accretion and cooling of lithospheric plates. Both fracture systems are inferred to have formed, in the Griffiths idealization, under nearly biaxial effective compressive loading on the order of 200 bar. The discrepancy between this value and the kilobar-order strengths of short-time laboratory tests reflects such factors as high temperature stress corrosion and fatigue. Fracture propagation is assumed to have been stable, but governed primarily by lateral load

Superhot Drilling in Iceland, the Experience of the Iceland Deep Drilling Project.

NASA Astrophysics Data System (ADS)

Elders, W. A.; Friðleifsson, G. Ó.; Zierenberg, R. A.; Fowler, A. P.

2017-12-01

The Iceland Deep Drilling Project aims to improve geothermal economics by producing supercritical fluids (www.iddp.is). Supercritical wells could yield an order of magnitude more usable energy than that from conventional geothermal wells because of higher enthalpy and enhanced flow properties. In 2009, the IDDP-1 well failed to reach supercritical conditions in the Krafla caldera in NE Iceland, after encountering rhyolite magma at only 2.1 km depth. The completed geothermal well became the world's hottest and produced superheated steam with a wellhead temperature of 452°C and flow sufficient to generate 35 MWe. The IDDP next moved SW to the Reykjanes Peninsula, the landward extension of the Mid-Atlantic Ridge, where it is possible to study an analog of the roots of a black smoker. Reykjanes is unique among Icelandic geothermal systems in being recharged by seawater, which has a critical point of 406°C at 298 bars. Drilling began by deepening an existing 2.5 km deep production well to 3 km depth, and then angling it towards the main upflow zone of the system, for a total slant depth of 4,659 m. Total circulation losses were encountered below 3 km that could not be cured by lost circulation materials or by multiple cement jobs. Accordingly, drilling continued to total depth without return of drill cuttings. We attempted 13 core runs below 3 km depth, only half of which recovered core. The cores are basalts and dolerites with alteration ranging from lower greenschist facies to lower amphibolite facies, suggesting formation temperatures >450°C. After the end of drilling in January 2017, following only six days of heating, supercritical conditions (426°C at 340 bars) were measured in the well at a depth of 4.5 km. The well has not yet been allowed to equilibrate to full in situ temperature. A perforated liner was inserted to 4,570 m, depth to facilitate temperature cycling to enhance permeability at depth through thermal cracking. In 2018 this will be followed by a

Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle

USGS Publications Warehouse

Foulger, G.R.; Pritchard, M.J.; Julian, B.R.; Evans, J.R.; Allen, R.M.; Nolet, G.; Morgan, W.J.; Bergsson, B.H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjord, K.

2001-01-01

We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all of Iceland 1996-1998. The structure of the upper mantle was determined using the ACH damped least-squares method and involved 42 stations, 3159 P-wave, and 1338 S-wave arrival times, including the phases P, pP, sP, PP, SP, PcP, PKIKP, pPKIKP, S, sS, SS, SKS and Sdiff. Artefacts, both perceptual and parametric, were minimized by well-tested smoothing techniques involving layer thinning and offset-and-averaging. Resolution is good beneath most of Iceland from ??? 60 km depth to a maximum of ??? 450 km depth and beneath the Tjornes Fracture Zone and near-shore parts of the Reykjanes ridge. The results reveal a coherent, negative wave-speed anomaly with a diameter of 200-250 km and anomalies in P-wave speed, Vp, as strong as -2.7 per cent and in S-wave speed, Vs, as strong as -4.9 per cent. The anomaly extends from the surface to the limit of good resolution at ??? 450 km depth. In the upper ??? 250 km it is centred beneath the eastern part of the Middle Volcanic Zone, coincident with the centre of the ??? 100 mGal Bouguer gravity low over Iceland, and a lower crustal low-velocity zone identified by receiver functions. This is probably the true centre of the Iceland hotspot. In the upper ??? 200 km, the low-wave-speed body extends along the Reykjanes ridge but is sharply truncated beneath the Tjornes Fracture Zone. This suggests that material may flow unimpeded along the Reykjanes ridge from beneath Iceland but is blocked beneath the Tjornes Fracture Zone. The magnitudes of the Vp, Vs and Vp/Vs anomalies cannot be explained by elevated temperature alone, but favour a model of maximum temperature anomalies <200 K, along with up to ??? 2 per cent of partial melt in the depth

Salinity variability along the eastern continental shelf of Canada and the United States, 1973-2013

NASA Astrophysics Data System (ADS)

Bisagni, James J.

2016-09-01

Continental shelf waters located off the east coast of Canada and the United States are part of a long shelf current system that is partly comprised of colder, less-saline waters originating from high latitudes, including waters from the North Atlantic sub-polar gyre, along with ice-melt and freshwater input from local rivers. A 41-year analysis (1973-2013) of near-surface salinity (NSS) using three hydrographic datasets (Bedford Institute of Oceanography "Climate", NOAA/ESDIM, and Canadian Marine Environmental Data Service (MEDS)) allowed an examination of NSS variability within 11 continental shelf sub-regions, extending from the southern Newfoundland Shelf of eastern Canada to the DelMarVa/Hatteras Shelf of the United States. Although the periods of record containing sufficient data vary between sub-regions, regional mean NSS values are lowest within the Gulf of St. Lawrence and highest on the DelMarVa/Hatteras shelf, with largest annual variability within the Gulf of St. Lawrence. After removal of outliers, long-term linear trends computed from annual mean NSS were detected along the Newfoundland Shelf (+0.011 y-1), Western Scotian Shelf (-0.007 y-1), Gulf of Maine (-0.014 y-1), Georges Bank (-0.011 y-1), and DelMarVa/Hatteras Shelf (+0.024 y-1). A long-term quadratic fit to annual mean NSS from the Eastern Scotian Shelf displays a salinity increase through 1992 of +0.026 y-1, decreasing thereafter until 2013 by -0.028 y-1. A quadratic fit for the Western Grand Banks displays a NSS increase through 2007 of +0.022 y-1, decreasing thereafter through 2013 by -0.006 y-1. Annual mean NSS from the Eastern Grand Banks, Tail of the Grand Banks, Gulf of St. Lawrence, and Middle Atlantic Bight display no long-term trends. Inter-annual variability (IAV) of NSS residuals shows similar small mean squared error (mse) of 0.02-0.04 for the four northern-most sub-regions (Newfoundland Shelf, Eastern, Tail and Western Grand Banks) and are correlated at 0-year lag. IAV of NSS

Biosamples, genomics, and human rights: context and content of Iceland's Biobanks Act.

PubMed

Winickoff, D E

2001-01-01

In recent years, human DNA sampling and collection has accelerated without the development of enforceable rules protecting the human rights of donors. The need for regulation of biobanking is especially acute in Iceland, whose parliament has granted a for-profit corporation, deCODE Genetics, an exclusive license to create a centralized database of health records for studies on human genetic variation. Until recently, how deCODE Genetics would get genetic material for its genotypic-phenotypic database remained unclear. However, in May 2000, the Icelandic Parliament passed the Icelandic Biobanks Act, the world's earliest attempt to construct binding rules for the use of biobanks in scientific research. Unfortunately, Iceland has lost an opportunity for bringing clear and ethically sound standards to the use of human biological samples in deCODE's database and in other projects: the Biobanks Act has extended a notion of "presumed consent" from the use of medical records to the use of patients' biological samples; worse, the act has made it possible--perhaps likely--that a donor's wish to withdraw his/her sample will be ignored. Inadequacies in the Act's legislative process help account for these deficiencies in the protection of donor autonomy.

The isotopic record of atmospheric lead fall-out on an Icelandic salt marsh since AD 50.

PubMed

Marshall, William A; Clough, Robert; Gehrels, W Roland

2009-04-01

We report a record of atmospheric Pb deposition at a coastal site in western Iceland that spans the last two millennia. The elemental concentrations of Pb, Al, Li and Ti are determined using ICP-MS from a sediment monolith collected from a salt marsh. Multicollector (MC) ICP-MS analysis is used to obtain isotopic ratios of stable Pb. The Pb/Ti and Pb/Li ratios are used to separate natural Pb background concentrations from Pb derived from remote anthropogenic sources. The pollution record in western Iceland is subdued in comparison with Pb records from the European mainland, but the isotopic character, profile and timing of Pb deposition show good agreement with the atmospheric Pb fall-out reported from sites in Scandinavia and northwestern Europe. At the bottom of the sequence we isolate a low-level (0.1-0.4 mg kg(-1)) Pb enrichment signal dated to AD 50-150. The isotopic signature and timing of this signal suggest Roman metal working industries as the source. In the subsequent millennium there was no significant or very low (i.e. elemental concentrations<0.01 mg kg(-1)) anthropogenic Pb deposition at the site up to, and including, the early Medieval period. Above a pumice layer, dated to AD 1226-1227, a small increase in Pb deposition is found. This trend is maintained until a more substantive and progressive increase is signalled during the late 1700s and early 1800s. This is followed by a substantial enrichment signal in the sediments (>3.0 mg kg(-1)) that is interpreted as derived from industrial coal burning and metal working during the 19th and 20th centuries in northern Europe. During the late 20th century, significant fall-out from European fuel additives reached Iceland.

Structural Evolution of Transform Fault Zones in Thick Oceanic Crust of Iceland

NASA Astrophysics Data System (ADS)

Karson, J. A.; Brandsdottir, B.; Horst, A. J.; Farrell, J.

2017-12-01

Spreading centers in Iceland are offset from the regional trend of the Mid-Atlantic Ridge by the Tjörnes Fracture Zone (TFZ) in the north and the South Iceland Seismic Zone (SISZ) in the south. Rift propagation away from the center of the Iceland hotspot, has resulted in migration of these transform faults to the N and S, respectively. As they migrate, new transform faults develop in older crust between offset spreading centers. Active transform faults, and abandoned transform structures left in their wakes, show features that reflect different amounts (and durations) of slip that can be viewed as a series of snapshots of different stages of transform fault evolution in thick, oceanic crust. This crust has a highly anisotropic, spreading fabric with pervasive zones of weakness created by spreading-related normal faults, fissures and dike margins oriented parallel to the spreading centers where they formed. These structures have a strong influence on the mechanical properties of the crust. By integrating available data, we suggest a series of stages of transform development: 1) Formation of an oblique rift (or leaky transform) with magmatic centers, linked by bookshelf fault zones (antithetic strike-slip faults at a high angle to the spreading direction) (Grimsey Fault Zone, youngest part of the TFZ); 2) broad zone of conjugate faulting (tens of km) (Hreppar Block N of the SISZ); 3) narrower ( 20 km) zone of bookshelf faulting aligned with the spreading direction (SISZ); 4) mature, narrow ( 1 km) through-going transform fault zone bounded by deformation (bookshelf faulting and block rotations) distributed over 10 km to either side (Húsavík-Flatey Fault Zone in the TFZ). With progressive slip, the transform zone becomes progressively narrower and more closely aligned with the spreading direction. The transform and non-transform (beyond spreading centers) domains may be truncated by renewed propagation and separated by subsequent spreading. This perspective

New geothermal heat flux map of Greenland and the Iceland hotspot track

NASA Astrophysics Data System (ADS)

Martos, Y. M.; Jordan, T. A.; Catalan, M.; Jordan, T. M.; Bamber, J. L.; Vaughan, D. G.

2017-12-01

Greenland is the second largest reservoir of water on Earth and about 80% of its surface is covered by ice. It is mainly composed of Archean blocks that collided during the Early Proterozoic. Indirect methods have been used to study its subglacial thermal conditions, geology and lithospheric structure. Numerous regions of basal melting are identified in the central and north Greenland but their relationship with geothermal heat flux is not yet clear. Crustal thickness derived by seismology and gravity data are consistent, showing no significant lateral variations, and providing average values of about 40 and 36 km respectively. Even though Greenland is considered a craton its crust has been affected by the presume passage of the Iceland hotspot since at least 100 Ma. Here we present the newest and highest resolution Curie Depth and geothermal heat flux maps for Greenland as well as their associated uncertainties. For estimating the Curie Depths we applied spectral methods to aeromagnetic data from the World Digital Magnetic Anomaly Map WDMAM2.0. Calculated Curie Depths vary from 25 to 50 km with shallower values located to the east. A thermal model is built based on the 1D heat conduction equation and considering steady state conditions. The thermal parameters are then optimized using local values derived from direct measurements, temperature profiles and more indirect methods such as radar imaging. The heat flux distribution shows higher spatial variability and a very different pattern than previously proposed and with values of 50-80 mW/m2. We identify a NW-SE high heat flux feature crossing Greenland which we correlate with the Iceland hotspot track. Additionally, to evaluate the lithospheric structure we calculate the Bouguer anomaly from GOCO5s satellite free air data and construct several gravity models across the proposed hotspot track. We show that a dense lower crust body in the same location the high heat flux trend is permissible from a gravimetric

Spatial stress variations in the aftershock sequence following the 2008 M6 earthquake doublet in the South Iceland Seismic Zone

NASA Astrophysics Data System (ADS)

Hensch, M.; Árnadóttir, Th.; Lund, B.; Brandsdóttir, B.

2012-04-01

The South Iceland Seismic Zone (SISZ) is an approximately 80 km wide E-W transform zone, bridging the offset between the Eastern Volcanic Zone and the Hengill triple junction to the west. The plate motion is accommodated in the brittle crust by faulting on many N-S trending right-lateral strike-slip faults of 2-5 km separation. Major sequences of large earthquakes (M>6) has occurred repeatedly in the SISZ since the settlement in Iceland more than thousand years ago. On 29th May 2008, two M6 earthquakes hit the western part of the SISZ on two adjacent N-S faults within a few seconds. The intense aftershock sequence was recorded by the permanent Icelandic SIL network and a promptly installed temporary network of 11 portable seismometers in the source region. The network located thousands of aftershocks during the following days, illuminating a 12-17 km long region along both major fault ruptures as well as several smaller parallel faults along a diffuse E-W trending region west of the mainshock area without any preceding main rupture. This episode is suggested to be the continuation of an earthquake sequence which started with two M6.5 and several M5-6 events in June 2000. The time delay between the 2000 and 2008 events could be due to an inflation episode in Hengill during 1993-1998, that potentially locked N-S strike slip faults in the western part of the SISZ. Around 300 focal solutions for aftershocks have been derived by analyzing P-wave polarities, showing predominantly strike-slip movements with occasional normal faulting components (unstable P-axis direction), which suggests an extensional stress regime as their driving force. A subsequent stress inversion of four different aftershock clusters reveals slight variations of the directions of the average σ3 axes. While for both southern clusters, including the E-W cluster, the σ3 axes are rather elongated perpendicular to the overall plate spreading axis, they are more northerly trending for shallower clusters

Volatiles in melt inclusions from Icelandic magmas

NASA Astrophysics Data System (ADS)

Nichols, A. R.; Wysoczanski, R. J.; Carroll, M. R.

2006-12-01

Melt inclusions hosted in olivine crystals from the glassy rims of subglacially erupted pillow basalts on Iceland have been analysed for volatiles, major elements and trace elements. Volatile measurements were undertaken using Fourier-Transform InfraRed spectroscopy utilising a novel technique which enables unexposed and much smaller inclusions than were previously possible to be analysed. Major elements were measured using electron microprobe and trace elements by laser ablation-inductively coupled plasma-mass spectrometry. Comparison between initial results from the inclusions and the compositions of the bulk glasses show that the inclusions are less evolved and contain more H2O at the same MgO content. In addition many of the inclusions have higher H2O/K2O than their bulk glasses and some even contain CO2 (up to 629 ppm), which is below detection limits in the bulk glasses. This indicates that these inclusions are less affected by degassing. Two inclusions have extreme H2O/K2O (> 10), possibly suggesting that they have assimilated hydrous crustal material. The volatile and major element compositions of the bulk glasses have been used to suggest that the Iceland mantle plume is wet. However, trace element measurements show that enriched Iceland magmas have lower H2O/Ce than the adjacent Reykjanes Ridge. This could reflect syn-eruptive degassing or mixing between undegassed and recycled degassed magmas. Alternatively Iceland magmas could be derived from the EM (enriched mantle) component, which is believed to represent recycled oceanic crust. It is suggested that this material is efficiently dehydrated during the subduction process, so even though it has an enriched character, H2O is relatively depleted. As a result, EM melts have higher absolute H2O contents than mid- ocean ridge basalts (MORB), but lower H2O/Ce (or other H2O-incompatible element ratios), which has led to EM plumes being termed `dampspots'. The inclusion data will be presented in this context

Decadal variability on the Northwest European continental shelf

NASA Astrophysics Data System (ADS)

Jones, Sam; Cottier, Finlo; Inall, Mark; Griffiths, Colin

2018-02-01

Decadal scale time series of the shelf seas are important for understanding both climate and process studies. Despite numerous investigations of long-term temperature variability in the shelf seas, studies of salinity variability are few. Salt is a more conservative tracer than temperature in shallow seas, and it can reveal changes in local hydrographic conditions as well as transmitted basin-scale changes. Here, new inter-annual salinity time series on the northwest European shelf are developed and a 13 year high resolution salinity record from a coastal mooring in western Scotland is presented and analysed. We find strong temporal variability in coastal salinity on timescales ranging from tidal to inter-annual, with the magnitude of variability greatest during winter months. There is little seasonality and no significant decadal trend in the coastal time series of salinity. We propose 4 hydrographic states to explain salinity variance in the shelf area west of Scotland based on the interaction between a baroclinic coastal current and wind-forced barotropic flow: while wind forcing is important, we find that changes in the buoyancy-driven flow are more likely to influence long-term salinity observations. We calculate that during prevailing westerly wind conditions, surface waters in the Sea of the Hebrides receive a mix of 62% Atlantic origin water to 38% coastal sources. This contrasts with easterly wind conditions, during which the mix is 6% Atlantic to 94% coastal sources on average. This 'switching' between hydrographic states is expected to impact nutrient transport and therefore modify the level of primary productivity on the shelf. This strong local variability in salinity is roughly an order of magnitude greater than changes in the adjacent ocean basin, and we infer from this that Scottish coastal waters are likely to be resilient to decadal changes in ocean climate.

High Proportions of Sub-micron Particulate Matter in Icelandic Dust Storms in 2015

NASA Astrophysics Data System (ADS)

Dagsson Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur; Magnusdottir, Agnes

2017-04-01

Iceland is extremely active dust region and desert areas of over 44,000 km2 acknowledge Iceland as the largest Arctic and European desert. Frequent dust events, up to 135 dust days annually, transport dust particles far distances towards the Arctic and Europe. Satellite MODIS pictures have revealed dust plumes exceeding 1,000 km. The annual dust deposition was calculated as 40.1 million tons yr-1. Two dust storms were measured in transverse horizontal profile about 90 km far from different dust sources in southwestern Iceland in the summer of 2015. Aerosol monitor DustTrak DRX 8533EP was used to measure PM mass concentrations corresponding to PM1, PM2.5, PM4, PM10 and the total PM15 at several places within the dust plume. Images from camera network operated by the Icelandic Road and Coastal Administration were used to estimate the visibility and spatial extent of measured dust events. A numerical simulation of surface winds was carried out with the numerical model HIRLAM with horizontal resolution of 5 km and used to calculate the total dust flux from the sources. The in situ measurements inside the dust plumes showed that aeolian dust can be very fine. The study highlights that suspended volcanic dust in Iceland causes air pollution with extremely high PM1 concentrations comparable to the polluted urban stations in Europe or Asia rather than reported dust event observations from around the world. The PM1/PM2.5 ratios are generally low during dust storms outside of Iceland, much lower than > 0.9 and PM1/PM10 ratios of 0.34-0.63 found in our study. It shows that Icelandic volcanic dust consists of higher proportion of submicron particles compared to crustal dust. The submicron particles are predicted to travel long distances. Moreover, such submicron particles pose considerable health risk because of high potential for entering the lungs. Icelandic volcanic glass has often fine pipe-vesicular structures known from asbestos and high content of heavy metals. Previous

Testing or Transforming Practice: Probing an Icelandic National Initiative to Improve Literacy Education

ERIC Educational Resources Information Center

Sigþórsson, Rúnar

2017-01-01

In the wake of a White Paper on Education Reform, published in 2014 by the Icelandic Ministry of Education, Science and Culture, the minister launched a national initiative to improve literacy education in Icelandic compulsory schools. The White Paper and the national initiative came as a reaction to the disappointing performance of 15-year-olds…

[Cost- effectiveness analysis of pneumococcal vaccination in Iceland].

PubMed

Björnsdóttir, Margrét

2010-09-01

Pneumococcus is a common cause of disease among children and the elderly. With the emergence of resistant serotypes, antibiotic treatment is getting limited. Many countries have therefore introduced a vaccination program among children against the most common serotypes. The aim of this study was to analyse cost-effectiveness of adding a vaccination program against pneumococcus in Iceland. A cost-effectiveness analysis was carried out from a societal perspective where the cost-effectiveness ratio ICER was estimated from the cost of each additional life and life year saved. The analyse was based on the year 2008 and all cost were calculated accordingly. The rate of 3% was used for net present-value calculation. Annual societal cost due to pneumococcus in Iceland was estimated to be 718.146.252 ISK if children would be vaccinated but 565.026.552 ISK if they would not be vaccinated. The additional cost due to the vaccination program was therefore 153.119.700 ISK . The vaccination program could save 0,669 lives among children aged 0-4 years old and 21.11 life years. The cost was 228.878.476 ISK for each additional life saved and 7.253.420 ISK for each additional life year saved. Given initial assumptions the results indicate that a vaccination programme against pneumococcal disease in Iceland would be cost effective.

Cross-Shelf Exchange.

PubMed

Brink, K H

2016-01-01

Cross-shelf exchange dominates the pathways and rates by which nutrients, biota, and materials on the continental shelf are delivered and removed. This follows because cross-shelf gradients of most properties are usually far greater than those in the alongshore direction. The resulting transports are limited by Earth's rotation, which inhibits flow from crossing isobaths. Thus, cross-shelf flows are generally weak compared with alongshore flows, and this leads to interesting observational issues. Cross-shelf flows are enabled by turbulent mixing processes, nonlinear processes (such as momentum advection), and time dependence. Thus, there is a wide range of possible effects that can allow these critical transports, and different natural settings are often governed by different combinations of processes. This review discusses examples of representative transport mechanisms and explores possible observational and theoretical paths to future progress.

Expanding the study of internet gambling behavior: trends within the Icelandic lottery and sportsbetting platform.

PubMed

Gray, Heather M; Jónsson, Guðberg K; LaPlante, Debi A; Shaffer, Howard J

2015-06-01

As rates of Internet gambling participation increase worldwide, so too does the need to understand how people engage in this form of gambling. This study represents the first examination of actual Internet gambling records within Iceland, a Nordic country with an active Internet lottery market that imposes strict regulations on gambling operator licenses. We summarized electronic betting records of a cohort of subscribers to the Internet betting service provider Íslensk Getspá. We observed that the typical subscriber bet approximately 3 days per month and made fewer than two bets per gambling day, each worth approximately the equivalent of $4 US. Subscribers lost the bulk (96%) of the amount they wagered, for a total loss of approximately $40 across the 2-year window of observation. Although these observations do not support the view of Internet gambling as an activity that is inherently risky for the typical subscriber, we did observe discontinuity across the distributions of gambling behavior, with the top 1% of subscribers making more than three bets per day.

A daily Azores-Iceland North Atlantic Oscillation index back to 1850.

PubMed

Cropper, Thomas; Hanna, Edward; Valente, Maria Antónia; Jónsson, Trausti

2015-07-01

We present the construction of a continuous, daily (09:00 UTC), station-based (Azores-Iceland) North Atlantic Oscillation (NAO) Index back to 1871 which is extended back to 1850 with additional daily mean data. The constructed index more than doubles the length of previously existing, widely available, daily NAO time series. The index is created using entirely observational sea-level pressure (SLP) data from Iceland and 73.5% of observational SLP data from the Azores - the remainder being filled in via reanalysis (Twentieth Century Reanalysis Project and European Mean Sea Level Pressure) SLP data. Icelandic data are taken from the Southwest Iceland pressure series. We construct and document a new Ponta Delgada SLP time series based on recently digitized and newly available data that extend back to 1872. The Ponta Delgada time series is created by splicing together several fractured records (from Ponta Delgada, Lajes, and Santa Maria) and filling in the major gaps (pre-1872, 1888-1905, and 1940-1941) and occasional days (145) with reanalysis data. Further homogeneity corrections are applied to the Azores record, and the daily (09:00 UTC) NAO index is then calculated. The resulting index, with its extended temporal length and daily resolution, is the first reconstruction of daily NAO back into the 19th Century and therefore is useful for researchers across multiple disciplines.

Holland in Iceland Revisited: An Emic Approach to Evaluating U.S. Vocational Interest Models

ERIC Educational Resources Information Center

Einarsdottir, Sif; Rounds, James; Su, Rong

2010-01-01

An emic approach was used to test the structural validity and applicability of Holland's (1997) RIASEC (Realistic, Investigative, Artistic, Social, Enterprising, Conventional) model in Iceland. Archival data from the development of the Icelandic Interest Inventory (Einarsdottir & Rounds, 2007) were used in the present investigation. The data…

Geothermal Cogeneration: Iceland's Nesjavellir Power Plant

ERIC Educational Resources Information Center

Rosen, Edward M.

2008-01-01

Energy use in Iceland (population 283,000) is higher per capita than in any other country in the world. Some 53.2% of the energy is geothermal, which supplies electricity as well as heated water to swimming pools, fish farms, snow melting, greenhouses, and space heating. The Nesjavellir Power Plant is a major geothermal facility, supplying both…

General practitioners' perceptions of the current status and pharmacists' contribution to primary care in Iceland.

PubMed

Blondal, Anna Bryndis; Jonsson, Jon Steinar; Sporrong, Sofia Kälvemark; Almarsdottir, Anna Birna

2017-08-01

Background For the past several years pharmacists' responsibilities have expanded globally from traditional tasks of dispensing medications to collaborating with other health care professionals in patient care. Similar developments have not occurred in outpatient settings in Iceland. Objective The aim of this study was to explore Icelandic general practitioners' views on the current status of primary care, their perceptions of pharmacists as a health care profession, and their attitudes towards future GP-pharmacist collaboration in primary care in Iceland. Setting Twelve primary care clinics in Iceland. Methods Semi-structured in-depth interviews were conducted with general practitioners from different primary care clinics in Iceland. A purposive and snowball sampling technique was used to select participants. All interviews were recorded and transcribed verbatim. The transcripts were categorized by themes and then analyzed using conventional content analysis. Main outcome measure General practitioners' attitudes towards pharmacists. Results Twenty general practitioners from twelve different primary care clinics in Iceland were interviewed. There are several unmet needs regarding medicines and patient monitoring in the Icelandic health care system. General practitioners suggested ways in which these gaps may be addressed and pharmacist-led clinical service was one of the suggestions. Currently, their communication with pharmacists in the primary sector solely surrounds practical non-clinical issues. Due to increasing polypharmacy and multimorbidity, they suggested that pharmacists should be more involved in patient care. Conclusions General practitioners believe that pharmacist-led clinical service can increase the quality of patient therapy. To improve communication between these health care providers, pharmacists must also re-professionalize (strengthening the profession´s status through new responsibilities and tasks), not having a conflict of interest and

Serum levels of marine-derived n-3 fatty acids in Icelanders, Japanese, Koreans, and Americans - A descriptive epidemiologic study

PubMed Central

Sekikawa, Akira; Steingrimsdottir, Laufey; Ueshima, Hirotsugu; Shin, Chol; Curb, J. David; Evans, Rhobert W.; Hauksdottir, Alda M.; Kadota, Aya; Choo, Jina; Masaki, Kamal; Thorsson, Bolli; Launer, Lenore J.; Garcia, Melisa E.; Maegawa, Hiroshi; Willcox, Bradley J.; Eiriksdottir, Gudny; Fujiyoshi, Akira; Miura, Katsuyuki; Harris, Tamara B.; Kuller, Lewis H.; Gudnason, Vilmundur

2012-01-01

Summary In the 1990’s Iceland and Japan were known as countries with high fish consumption whereas coronary heart disease (CHD) mortality in Iceland was high and that in Japan was low among developed countries. We described recent data fish consumption and CHD mortality from publicly available data. We also measured CHD risk factors and serum levels of marine-derived n-3 and other fatty acids from population-based samples of 1,324 men in Iceland, Japan, South Korea, and the US. CHD mortality in men in Iceland was almost 3 times as high as that in Japan and South Korea. Generally a profile of CHD risk factors in Icelanders compared to Japanese was more favorable. Serum marine-derived n-3 fatty acids in Iceland were significantly lower than in Japan and South Korea but significantly higher than in the US. PMID:22658580

Meteorological buoy measurements in the Iceland Sea, 2007-2009

NASA Astrophysics Data System (ADS)

Nína Petersen, Guðrún

2017-10-01

The Icelandic Meteorological Office (IMO) conducted meteorological buoy measurements in the central Iceland Sea in the time period 2007-2009, specifically in the northern Dreki area on the southern segment of the Jan Mayen Ridge. Due to difficulties in deployment and operations, in situ measurements in this region are sparse. Here the buoy, deployment and measurements are described with the aim of giving a future user of the data set information that is as comprehensive as possible. The data set has been quality-checked, suspect data removed and the data set made publicly available from PANGAEA Data Publisher (https://doi.org/10.1594/PANGAEA.876206).

Esperanto and Icelandic: Two Contrasting Lexical Systems

ERIC Educational Resources Information Center

Gutmans, Theodore

1972-01-01

The article comprises a table listing Esperanto words conveying international concepts, accompained by equivalents in English, French, German, Russian, Hungarian, Hebrew and Icelandic, representing various language groups. The comparison shows that although the world language would opt for international terms, a language making no claims on…

Contrasting geochemical trends in the fertile and refractory parts of the NE Atlantic mantle source

NASA Astrophysics Data System (ADS)

Tronnes, R. G.; Debaille, V.; Brandon, A. D.; Waight, T. E.; Graham, D. W.; Williams, A.; Lee, C. A.

2008-12-01

Primitive alkaline basalts from the Icelandic off-rift volcanic zones and Jan Mayen represent low-degree melts from the fertile parts of the NE Atlantic mantle. Olivine tholeiites and picrites from the Icelandic rift zones and nearby oceanic spreading ridges are formed by protracted decompressional melting. The V-shaped ridges along the Reykjanes, Kolbeinsey and Aegir ridges indicate that ascending source material is supplied by a pulsating plume and deflected laterally for distances of about 1000 km from Iceland (Jones et al. GGG 2002; Breivik et al. JGR 2006). Plume material deflected in the direction of the rift zones and spreading ridges undergoes extensive melting at shallow level, whereas material deflected in other directions flows laterally at deeper levels and remains largely unmelted and more fertile. The comparison of a sample suite of primitive off-rift basalts from Iceland and Jan Mayen (Debaille et al., in prep.) with olivine tholeiites and picrites from the Icelandic rift zones (mainly Brandon et al. GCA 2007) demonstrate opposing geochemical trends. The degree of source enrichment, expressed by the La/Sm-ratio, is positively and negatively correlated with 87/86Sr and 143/144Nd throughout the entire range of depleted rift zone tholeiites and enriched off-rift basalts. In the rift zone tholeiites the La/Sm-ratio has negative correlations with Mg# and Mg-content and positive correlations with 187/188Os and 3/4He. These four trends have opposite equivalents for the off-rift basalts. The most enriched and alkaline basalts from Jan Mayen and Snæfellsnes have the lowest 3/4He of 6-9*Ra and 187/188Os of 0.12-0.13. The trends seem to require a source component with ancient melt depletion and subsequent enrichment. A subcontinental lithospheric mantle keel (SCLM) is the most likely origin for the enriched component with high LILE, La/Sm and 87/86Sr and low 143/144Nd, 3/4He and 187/188Os. The most enriched alkaline basalts have notably higher Mg# and Mg and

Determination of shelf heat transfer coefficients along the shelf flow path of a freeze dryer using the shelf fluid temperature perturbation approach.

PubMed

Kuu, Wei Y; Nail, Steven L; Hardwick, Lisa M

2007-01-01

The spatial distribution of local shelf heat transfer coefficients, Ks, was determined by mapping the transient temperature response of the shelf surface along the serpentine internal channels of the shelf while the temperature of the heat transfer fluid was ramped from -40 degrees to 40 degrees C. The solution of a first-order non-steady-state differential equation resulted in a predicted shelf surface temperature as a function of the shelf fluid temperature at any point along the flow path. During the study, the shelf surfaces were maintained under a thermally insulated condition so that the heat transfers by gas conduction and radiation were negligible. To minimize heat conduction by gas, the chamber was evacuated to a low pressure, such as 100 mTorr. To minimize heat transfers between shelves, shelves were moved close together, with a gap of approximately 3 mm between any two shelves, because the shelf surface temperatures at corresponding vertical locations of two shelves are virtually equal. In addition, this also provides a shielding from radiation heat transfer from shelf to walls. Local heat transfer coefficients at the probed locations h(x) ( approximately Ks) were calculated by fitting the experimental shelf temperature response to the theoretical value. While the resulting values of K(s) are in general agreement with previously reported values, the values of Ks close to the inlet are significantly higher than those of other locations of the shelf channel. This observation is most likely attributed to the variation of the flow pattern of heat transfer fluid within the channels.

Network analysis of the Íslendinga sögur - the Sagas of Icelanders

NASA Astrophysics Data System (ADS)

Mac Carron, P.; Kenna, R.

2013-10-01

The Íslendinga sögur - or Sagas of Icelanders - constitute a collection of medieval literature set in Iceland around the late 9th to early 11th centuries, the so-called Saga Age. They purport to describe events during the period around the settlement of Iceland and the generations immediately following and constitute an important element of world literature thanks to their unique narrative style. Although their historicity is a matter of scholarly debate, the narratives contain interwoven and overlapping plots involving thousands of characters and interactions between them. Here we perform a network analysis of the Íslendinga sögur in an attempt to gather quantitative information on interrelationships between characters and to compare saga society to other social networks.

Gradual slowdown and thickening of Fimbulisen ice shelf, East Antarctica, over the past decade

NASA Astrophysics Data System (ADS)

van Oostveen, Jelte; Moholdt, Geir; Kääb, Andreas; Matsuoka, Kenichi

2017-04-01

Fimbulisen is a fast-flowing (up to 780±10 ma-1) ice shelf in the Dronning Maud Land region of East Antarctica. Fed by one of the few major outlet glaciers along that coast, Jutulstraumen, the ice shelf has the potential to affect the stability of a considerable part of the inland ice sheet. Here we present evidence of a slowdown and thickening of Fimbulisen over the last decade. We derive ice shelf velocities using synthetic aperture radar (SAR) data from Envisat in 2008 and Radarsat-2 in 2015. We find that the speeds of Fimbulisen have decreased by 10±2 ma-1 over the last 7 years, which is confirmed with repeated GPS stake readings from 2010-2011. The slow-down of Fimbulisen coincides with a gradual ice shelf thickening that we infer from ICESat (2003-2009) and CryoSat-2 (2010-2016) altimetry. Available surface mass balance data from Fimbulisen show no clear trends over the past decades, suggesting that ice dynamics is the main explanation for the observed thickening. Considering that Fimbulisen is in a long-term phase of advance after its main tongue calved off in 1967, it is plausible that the slowdown is cyclic and related to the longitudinal expansion of the ice shelf. In support of this theory we have found several uncharted ice rumples and stationary icebergs near the eastern front of the ice shelf, indicating the presence of shallow bathymetry that might affect the ice shelf dynamics considerably in the event of ice shelf grounding or ungrounding.

Assessing δ18O heterogeneity in Icelandic olivine crystals

NASA Astrophysics Data System (ADS)

Bar Rasmussen, M.; Halldorsson, S. A.; Martin, W.; Gibson, S. A.; Hilton, D. R.

2017-12-01

δ18O systematics of Icelandic basalts are notably distinct from MORB-sourced basalts. This difference has previously been attributed to interaction with low δ18O meteoric water in the crust or slight heterogeneity within the Icelandic mantle [1]. Studies addressing this issue have mostly involved batch mineral laser-fluorination analysis which cannot resolve any intra-mineral δ18O variability that might be present due to shallow-level processes, e.g. crustal contamination [2]. We present a study of olivine crystals found in basalts covering the neovolcanic rift and flank zones as well as older Tertiary crust, in which we couple in-situ δ18O-measurements with major and trace elements using SIMS, high-precision EMP and LA ICP-MS. Most samples have previously been analysed for 3He/4He which ranges from 6.7 to 47.8 RA, the largest span reported for any oceanic island [3]. Our analysed olivine grains, range in Fo# between 79.9 to 91.8 with limited intra-grain variability. Independent of Fo#, we observe a variation in δ18O(Ol) of >3 ‰ across Iceland, with most crystals plotting below the expected depleted mantle-value ( 5.1 ± 0.2‰ [4]). The lowest δ18O(Ol) of +2.77 ‰, is found in crystals with Fo# 86 from central Iceland, closest to the inferred plume head [3]. Trace element ratios for these olivine grains (e.g. Zn/Fe) strongly indicate a peridotitic mantle source, which implies a shallow (likely crustal) origin of low δ18O(Ol) for this region. In contrast, olivine crystals from the South Iceland Volcanic Zone (a region of active rift propagation and transitional to alkalic volcanism) display trace element ratios that are indicative of a greater amount of pyroxenite in their melt source region. The δ18O(Ol) of these samples vary significantly (from +3.45 to +4.98 ‰) which, together with their elevated 3He/4He values, implies entrainment of a lower δ18O mantle-source by a less-degassed mantle plume source. Further modelling will be performed to evaluate

Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica

NASA Astrophysics Data System (ADS)

De Rydt, Jan; Hilmar Gudmundsson, G.; Nagler, Thomas; Wuite, Jan; King, Edward C.

2018-02-01

We report on the recent reactivation of a large rift in the Brunt Ice Shelf, East Antarctica, in December 2012 and the formation of a 50 km long new rift in October 2016. Observations from a suite of ground-based and remote sensing instruments between January 2000 and July 2017 were used to track progress of both rifts in unprecedented detail. Results reveal a steady accelerating trend in their width, in combination with alternating episodes of fast ( > 600 m day-1) and slow propagation of the rift tip, controlled by the heterogeneous structure of the ice shelf. A numerical ice flow model and a simple propagation algorithm based on the stress distribution in the ice shelf were successfully used to hindcast the observed trajectories and to simulate future rift progression under different assumptions. Results show a high likelihood of ice loss at the McDonald Ice Rumples, the only pinning point of the ice shelf. The nascent iceberg calving and associated reduction in pinning of the Brunt Ice Shelf may provide a uniquely monitored natural experiment of ice shelf variability and provoke a deeper understanding of similar processes elsewhere in Antarctica.

Phytoplankton bloom off western Iceland

NASA Image and Video Library

2017-12-08

NASA image captured 06/24/2010 at 14 :30 UTC Phytoplankton bloom off western Iceland Satellite: Aqua NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team To learn more about MODIS go to: rapidfire.sci.gsfc.nasa.gov/gallery/?latest NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

NASA Astrophysics Data System (ADS)

Cochran, James R.; Tinto, Kirsty J.; Bell, Robin E.

2015-05-01

Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5-1.7 with 80-100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. The copyright line for this article was changed on 5 JUN 2015 after original online publication.

Psychometric testing of the Iceland Health Care Practitioner Illness Beliefs Questionnaire among school nurses.

PubMed

Svavarsdottir, Erla Kolbrun; Looman, Wendy; Tryggvadottir, Gudny Bergthora; Garwick, Ann

2018-03-01

Beliefs have been found to have an effect on how people deal with illness. Therefore, knowing healthcare practitioners' beliefs about specific high frequency illnesses are vital when caring for vulnerable populations such as school-age children with chronic illnesses or disorders. To psychometrically test the Iceland Health Care Practitioner Illness Beliefs Questionnaire for healthcare professionals who are working with families of school-age children with asthma and attention deficit/hyperactivity disorder. The Iceland Health Care Practitioner Illness Beliefs Questionnaire is a 7-item Likert-type instrument with four additional open-ended questions that was developed from the Iceland Family Illness Belief Questionnaire. The questionnaire is designed to measure a provider's beliefs about their understanding of the meaning of the illness situation for families. The questionnaire was administered to 162 school nurses in Iceland and the state of Minnesota. Two condition-specific versions of the Iceland Health Care Practitioner Illness Beliefs Questionnaire were developed in this study: one to measure beliefs about families of children with asthma and one to measure beliefs about families of children with attention deficit hyperactivity disorder. Higher scores on the questionnaire indicate that healthcare professionals are more confident in their illness beliefs. After initial development, the questionnaire was translated into English. Participants completed the questionnaire using an online survey platform and parallel study procedures in both countries. Based on exploratory factor analysis using principal component analysis, the Iceland Health Care Practitioner Illness Beliefs Questionnaire was found to have a one-factor solution with good construct validity (Cronbach's α = 0.91). Confirmatory factor analysis supported the one-factor solution (Cronbach's α = 0.91). This instrument is a promising tool for measuring illness beliefs among healthcare practitioners

Ash plume from Eyjafjallajokull Volcano, Iceland May 6th View

NASA Image and Video Library

2010-05-06

NASA satellite image acquired May 6, 2010 at 11 :55 UTC To view a detail of this image go to: www.flickr.com/photos/gsfc/4583711511/ NASA Satellite Sees a Darker Ash Plume From Iceland Volcano NASA's Terra satellite flew over the Eyjafjallajokull Volcano, Iceland, on May 6 at 11:55 UTC (7:55 a.m. EDT). The Moderate Resolution Imaging Spectroradiometer instrument known as MODIS that flies onboard Terra, captured a visible image of the ash plume. The plume was blowing east then southeast over the Northern Atlantic. The satellite image shows that the plume is at a lower level in the atmosphere than the clouds that lie to its east, as the brown plume appears to slide underneath the white clouds. Satellite: Terra NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team To learn more about MODIS go to: www.nasa.gov/topics/earth/features/iceland-volcano-plume.... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Children's Outdoor Environment in Icelandic Educational Policy

ERIC Educational Resources Information Center

Norðdahl, Kristín; Jóhannesson, Ingólfur Ásgeir

2015-01-01

The aim of this study is to investigate what characterizes the discourse on the role of the outdoor environment in young children's learning in educational policy documents in Iceland. Policy documents, laws and regulations, national curriculum guides for pre- and compulsory school levels, and documents from municipalities were analyzed. A…

The Sulfur Dioxide Plume from the February 26, 2000 Eruption of Mt. Hekla, Iceland

NASA Technical Reports Server (NTRS)

Krueger, Arlin J.; Krotkov, N. A.; Einaudi, Franco (Technical Monitor)

2000-01-01

The February 2000 fissure eruption of Mt. Hekla, Iceland was captured in sulfur dioxide data from the Earth Probe TOMS. A special algorithm is used to discriminate sulfur dioxide from ozone. The eruption began at 18:19 GMT on February 26, 2000 and was first viewed by TOMS at 09:55 GMT on February 27. The volcanic cloud at that time appeared as a very long and narrow arc extending west from the volcano in southern Iceland, then north across Greenland, and finally east towards Norway. The cloud altitude was reported from aircraft sightings and data to be above 10 km. The circulation of a ridge located north of Iceland produced the large arc shaped cloud. As the eruption is non-explosive the high altitude cloud contains little ash. Almost all the ash from the eruption fell out locally across Iceland. By February 29, the sulfur dioxide cloud had drifted eastward in a band along the Barents Sea coast of Norway and Russia. The analysis includes an assessment of the initial sulfur dioxide content and its rate of conversion to sulfate.

Arctic geodynamics: Continental shelf and deep ocean geophysics. ERS-1 satellite altimetry: A first look

NASA Technical Reports Server (NTRS)

Anderson, Allen Joel; Sandwell, David T.; Marquart, Gabriele; Scherneck, Hans-Georg

1993-01-01

An overall review of the Arctic Geodynamics project is presented. A composite gravity field model of the region based upon altimetry data from ERS-1, Geosat, and Seasat is made. ERS-1 altimetry covers unique Arctic and Antarctic latitudes above 72 deg. Both areas contain large continental shelf areas, passive margins, as well as recently formed deep ocean areas. Until ERS-1 it was not possible to study these areas with satellite altimetry. Gravity field solutions for the Barents sea, portions of the Arctic ocean, and the Norwegian sea north of Iceland are shown. The gravity anomalies around Svalbard (Spitsbergen) and Bear island are particularly large, indicating large isostatic anomalies which remain from the recent breakup of Greenland from Scandinavian. Recently released gravity data from the Armed Forces Topographic Service of Russia cover a portion of the Barents and Kara seas. A comparison of this data with the ERS-1 produced gravity field is shown.

Motion in the north Iceland volcanic rift zone accommodated by bookshelf faulting

NASA Astrophysics Data System (ADS)

Green, Robert G.; White, Robert S.; Greenfield, Tim

2014-01-01

Along mid-ocean ridges the extending crust is segmented on length scales of 10-1,000km. Where rift segments are offset from one another, motion between segments is accommodated by transform faults that are oriented orthogonally to the main rift axis. Where segments overlap, non-transform offsets with a variety of geometries accommodate shear motions. Here we use micro-seismic data to analyse the geometries of faults at two overlapping rift segments exposed on land in north Iceland. Between the rift segments, we identify a series of faults that are aligned sub-parallel to the orientation of the main rift. These faults slip through left-lateral strike-slip motion. Yet, movement between the overlapping rift segments is through right-lateral motion. Together, these motions induce a clockwise rotation of the faults and intervening crustal blocks in a motion that is consistent with a bookshelf-faulting mechanism, named after its resemblance to a tilting row of books on a shelf. The faults probably reactivated existing crustal weaknesses, such as dyke intrusions, that were originally oriented parallel to the main rift and have since rotated about 15° clockwise. Reactivation of pre-existing, rift-parallel weaknesses contrasts with typical mid-ocean ridge transform faults and is an important illustration of a non-transform offset accommodating shear motion between overlapping rift segments.

Body condition score, morphometric measurements and estimation of body weight in mature Icelandic horses in Denmark.

PubMed

Jensen, Rasmus B; Danielsen, Signe H; Tauson, Anne-Helene

2016-10-20

Obesity is related to the development of several diseases like insulin resistance and laminitis in horses. The prevalence of obesity among mature Icelandic horses in Denmark has not been investigated previously. This study aimed to find the prevalence of obesity, to compare body condition score (BCS) based on owner perception with that of an experienced person and to correlate the BCS to body weight (BW) and morphometric measures in a group of mature Icelandic horses in Denmark. A total of 254 Icelandic horses (≥4 years; 140 geldings, 105 mares, 9 stallions) from 46 different farms were included. All horses were assigned a BCS on a scale from 1 to 9 (1 is poor, 5 is moderate and 9 is extremely fat) by their owner and by an experienced person. Two weight tapes were used to assess BW. Girth circumference (GC), neck circumference (NC) and height at withers (HW) were measured, and the GC:HW and NC:HW ratios were calculated. Categorising the horses into four groups, 5.9 % were underweight (BCS 3-4), 70.1 % were optimal (BCS 5-6), 13.8 % were overweight (BCS 7) and 10.2 % were obese (BCS 8-9). The GC:HW and NC:HW ratios increased with increasing BCS, as did the BW estimated with the weight tapes. A GC:HW ratio >1.21 might indicate overweight or obesity in Icelandic horses. Horse owners underestimated the BCS of their horses compared to an experienced person. The results from this study show that 24.0 % of mature Icelandic horses in Denmark are overweight or obese, and that owners tend to underestimate the BCS of their Icelandic horses. The GC:HW ratio might indicate overweight or obesity, however, the ratio for Icelandic horses is different than reported for horses and ponies of other breeds.

Seasonal sea ice cover during the warm Pliocene: Evidence from the Iceland Sea (ODP Site 907)

NASA Astrophysics Data System (ADS)

Clotten, Caroline; Stein, Ruediger; Fahl, Kirsten; De Schepper, Stijn

2018-01-01

Sea ice is a critical component in the Arctic and global climate system, yet little is known about its extent and variability during past warm intervals, such as the Pliocene (5.33-2.58 Ma). Here, we present the first multi-proxy (IP25, sterols, alkenones, palynology) sea ice reconstructions for the Late Pliocene Iceland Sea (ODP Site 907). Our interpretation of a seasonal sea ice cover with occasional ice-free intervals between 3.50-3.00 Ma is supported by reconstructed alkenone-based summer sea surface temperatures. As evidenced from brassicasterol and dinosterol, primary productivity was low between 3.50 and 3.00 Ma and the site experienced generally oligotrophic conditions. The East Greenland Current (and East Icelandic Current) may have transported sea ice into the Iceland Sea and/or brought cooler and fresher waters favoring local sea ice formation. Between 3.00 and 2.40 Ma, the Iceland Sea is mainly sea ice-free, but seasonal sea ice occurred between 2.81 and 2.74 Ma. Sea ice extending into the Iceland Sea at this time may have acted as a positive feedback for the build-up of the Greenland Ice Sheet (GIS), which underwent a major expansion ∼2.75 Ma. Thereafter, most likely a stable sea ice edge developed close to Greenland, possibly changing together with the expansion and retreat of the GIS and affecting the productivity in the Iceland Sea.

Floating like a cork: The importance of glacial isostasy in the deglaciation progress in Iceland

NASA Astrophysics Data System (ADS)

Norddahl, H.; Ingolfsson, O.

2016-12-01

Being positioned on top of a hotspot and between two spreading ocean plates explains rheological structure of Iceland and the properties of a 30-35 km thick lithosphere, possibly with high proportion of partial melt, on top of a low viscous asthenosphere below Iceland, in the middle of the North Atlantic Ocean. Rapid variations in glacier loading on the Iceland crust have been proved to generate more or less an instantaneous depression or uplift of the crust and, thus, uphold both temporal and spacial glacio-isostatic equilibrium. Formation of a shoreline requires at least temporal equilibrium between glacial isostasy and eustasy. Eminent raised shorelines - found throughout Iceland - were formed during two separate but consecutive culmination of climatically induced glacier re-advance and consequent transgression of relative sea-level in Younger Dryas and Preboreal times (12.0 and 11.3 kcal BP). A Marine Limit shoreline in W Iceland was formed at 14.7 kcal BP, subsequent to a collapse-like retreat of the marine based part of the Icelandic Ice Sheet (IIS) and just prior to the onset of the Bølling warming, i.e. during a period of anticipated rapid isostatic uplift. A temporary glacio-isostatic equilibrium at that time is best explained by changes in the mode of deglaciation generating dynamic changes within the Ice Sheet itself, changes that resulted in reduced rates of mass-loss and glacio-isostatic uplift to such a degree that a temporal quasi-equilibrium between eustatic rise and isostatic uplift was established. Formation of well-developed raised shoreline is generally regarded as a deglaciation proxy signaling large ice volume changes. Formation of the ML shoreline in W Iceland during the rapid climatic improvement at the beginning of the Bølling/Allerød Interstadial underlines the importance of, beside the geological data, also to take into consideration physical properties of both the lithosphere and asthenosphere in each location.

Thermostable Shelf Life Study

NASA Technical Reports Server (NTRS)

Perchonok, M. H.; Antonini, D. K.

2008-01-01

The objective of this project is to determine the shelf life end-point of various food items by means of actual measurement or mathematical projection. The primary goal of the Advanced Food Technology Project in these long duration exploratory missions is to provide the crew with a palatable, nutritious and safe food system while minimizing volume, mass, and waste. The Mars missions could be as long as 2.5 years with the potential of the food being positioned prior to the crew arrival. Therefore, it is anticipated that foods that are used during the Mars missions will require a 5 year shelf life. Shelf life criteria are safety, nutrition, and acceptability. Any of these criteria can be the limiting factor in determining the food's shelf life. Due to the heat sterilization process used for the thermostabilized food items, safety will be preserved as long as the integrity of the package is maintained. Nutrition and acceptability will change over time. Since the food can be the sole source of nutrition to the crew, a significant loss in nutrition may determine when the shelf life endpoint has occurred. Shelf life can be defined when the food item is no longer acceptable. Acceptability can be defined in terms of appearance, flavor, texture, or aroma. Results from shelf life studies of the thermostabilized food items suggest that the shelf life of the foods range from 0 months to 8 years, depending on formulation.

Thermostabilized Shelf Life Study

NASA Technical Reports Server (NTRS)

Perchonok, Michele H.; Catauro, Patricia M.

2009-01-01

The objective of this project is to determine the shelf life end-point of various food items by means of actual measurement or mathematical projection. The primary goal of the Advanced Food Technology Project in these long duration exploratory missions is to provide the crew with a palatable, nutritious and safe food system while minimizing volume, mass, and waste. The Mars missions could be as long as 2.5 years with the potential of the food being positioned prior to the crew arrival. Therefore, it is anticipated that foods that are used during the Mars missions will require a 5 year shelf life. Shelf life criteria are safety, nutrition, and acceptability. Any of these criteria can be the limiting factor in determining the food's shelf life. Due to the heat sterilization process used for the thermostabilized food items, safety will be preserved as long as the integrity of the package is maintained. Nutrition and acceptability will change over time. Since the food can be the sole source of nutrition to the crew, a significant loss in nutrition may determine when the shelf life endpoint has occurred. Shelf life can be defined when the food item is no longer acceptable. Acceptability can be defined in terms of appearance, flavor, texture, or aroma. Results from shelf life studies of the thermostabilized food items suggest that the shelf life of the foods range from 0 months to 8 years, depending on formulation.

Transgressive systems tract development and incised-valley fills within a quaternary estuary-shelf system: Virginia inner shelf, USA

USGS Publications Warehouse

Foyle, A.M.; Oertel, G.F.

1997-01-01

, and occur within large, coast-oblique trending depressions (paleo-estuaries). Style 1 is dominated by fluvial through estuary-mouth depositional systems (Seismic Facies 1-4). Style 2 sequence preservation, represented by Sequences III and II, is dominantly an inner shelf and shoreface succession with a seaward-thickening tabular wedge geometry that does not exceed 15 m in thickness. These shoreface and inner shelf depositional systems of the upper transgressive systems tract (Seismic Facies 9) and highstand systems tract (Seismic Facies 7 and 11) are not associated with paleo-estuaries. Style 3 sequence preservation is represented by Sequence 1, the Holocene Sequence. It consists of lower transgressive systems tract fluvial-estuarine, lagoonal, and tidal-inlet fill deposits (Seismic Facies 1-6, and 8) overlain by upper transgressive systems tract shelf and shoreface sands (Seismic Facies 9). Style 3 has a crenulated wedge geometry, and is thickest beneath and seaward of the modern Chesapeake Bay mouth. It thins northward and landward onto Late Pleistocene interfluvial highs on the basinward side of the southern Delmarva Peninsula.

Cloud-Free View of Iceland

NASA Image and Video Library

2015-04-16

This nearly cloud-free image of Iceland was captured by the MODIS instrument on board the Terra spacecraft on 04/15/2015 at 13:00 UTC. 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

Mud transportation on a steep shelf, Rio de La Plata shelf, Puerto Rico

USGS Publications Warehouse

Grove, K.A.; Pilkey, O.H.; Trumbull, J.V.A.

1982-01-01

Hurricanes David (August 29-30, 1979) and Frederick (September 2-5, 1979) caused major flooding of the Rio de La Plata in northern Puerto Rico. A thin mud layer was deposited across the narrow insular shelf adjacent to the river mouth. Within 5 months, fair-weather shelf-winnowing processes moved the mud layer entirely from the shelf, 0.5 to 2 km to the shelf break at the 50-m contour and beyond. The process of mud movement is termed 'mud hopping.' ?? 1982 A. M. Dowden, Inc.

[The prevalence of sexual abuse and sexual assault against icelandic adolescents].

PubMed

Arnarsson, Arsaell Mar; Gisladottir, Kristin Heba; Jonsson, Stefan Hrafn

2016-06-01

Sexual abuse and sexual assaults against children and adolescents is one of the most significant threats to their health. The aim of the current study was to investigate its prevalence and effects on Icelandic teenagers in the 10th grade. The study is based on data collected for the Icelandic part of the HBSC-project (Health and behaviour of school- aged children). Standardized questionnaires were sent to all students in 10th grade in Iceland of which 3,618 participated. The students experience of sexual abuse or assaults was assessed by asking them how often they had been against their will a) touched in a sexual way, b) made to touch someone else in a sexual way, c) the subject of an attempted rape or d) subjected to rape. The results showed that 14.6% (527) participants had experienced sexual abuse or assault. Of these, 4.5% (162) had one such experience but 10.1% had either suffered certain type of abuse or assault more than once, or had experienced more than one kind. About 1% of participants (35) said that they had suffered many times from many forms of abuse and assaults. The prevalence of poor mental well-being and risk behaviour was much higher amongst those that had experienced sexual abuse or assault. Although the results show that the prevalence of sexual abuse and assault against Icelandic adolescents is similar to other Western countries, we find it to be higher than a previous study a decade ago. Sexual abuse, sexual assault, adolescents. Correspondence: Arsaell Mar Arnarsson, aarnarsson@unak.is.

Postglacial eruptive history of the Western Volcanic Zone, Iceland

NASA Astrophysics Data System (ADS)

Sinton, John; GröNvold, Karl; SæMundsson, KristjáN.

2005-12-01

New field observations, age constraints, and extensive chemical analyses define the complete postglacial eruptive history of the 170-km-long Western Volcanic Zone (WVZ) of Iceland, the ultraslow-spreading western boundary of the south Iceland microplate. We have identified 44 separate eruptive units, 10 of which are small-volume eruptions associated with the flanking Grímsnes system. Overall chemical variations are consistent with very simplified models of melting of a source approximating primitive mantle composition. The 17 eruptions in the first 3000 years of postglacial time account for about 64% of the total postglacial production and are incompatible-element depleted compared to younger units, consistent with enhanced melting as a consequence of rebound immediately following deglaciation. Steadily declining eruption rates for the last 9000 years also correlate with changes in average incompatible element ratios that appear to reflect continued decline in melting extents to the present day. This result is not restricted to the WVZ, however, and may herald a decline in melting throughout all of western Iceland during later postglacial time. Lavas from the northern part of the WVZ are depleted in incompatible elements relative to those farther south at all times, indicating either a long-wavelength gradient in mantle source composition or variations in the melting process along axis. We find no evidence in the postglacial volcanic record for current failure of the WVZ, despite evidence for continued propagation of the eastern margin of the microplate. The dominance of lava shields in the eruptive history of the WVZ contrasts with the higher number of fissure eruptions in other Icelandic volcanic zones. WVZ shields represent long-duration, low-effusion rate eruptions fed by recharge magma arising out of the mantle. Average effusion rate is the key variable distinguishing shield and fissure eruptions, both within the WVZ and between different volcanic zones. High

Professional Learning outside the Classroom: Expedition Iceland

ERIC Educational Resources Information Center

Jordan, Julie; Bull, Sue

2012-01-01

A bunch of intrepid teachers spent a week in Iceland in a quest to learn more about the country's challenging landscape, by engaging in a unique and inspiring professional development opportunity to learn about innovative ways to teach science and mathematics outside of a classroom setting. A 2008 Ofsted report highlighted the benefits of learning…

Polish Complementary Schools in Iceland and England

ERIC Educational Resources Information Center

Zielinska, Malgorzata; Kowzan, Piotr; Ragnarsdóttir, Hanna

2014-01-01

Since 2004, the opening of labour markets has spurred a considerable number of Poles to emigrate e.g. to Iceland and England. Families with school age children have had the challenge of adapting to foreign environments and school systems. Polish complementary schools have played an important, albeit ambivalent, role in this process. Through focus…

Microbial diversity on Icelandic glaciers and ice caps.

PubMed

Lutz, Stefanie; Anesio, Alexandre M; Edwards, Arwyn; Benning, Liane G

2015-01-01

Algae are important primary colonizers of snow and glacial ice, but hitherto little is known about their ecology on Iceland's glaciers and ice caps. Due do the close proximity of active volcanoes delivering large amounts of ash and dust, they are special ecosystems. This study provides the first investigation of the presence and diversity of microbial communities on all major Icelandic glaciers and ice caps over a 3 year period. Using high-throughput sequencing of the small subunit ribosomal RNA genes (16S and 18S), we assessed the snow community structure and complemented these analyses with a comprehensive suite of physical-, geo-, and biochemical characterizations of the aqueous and solid components contained in snow and ice samples. Our data reveal that a limited number of snow algal taxa (Chloromonas polyptera, Raphidonema sempervirens and two uncultured Chlamydomonadaceae) support a rich community comprising of other micro-eukaryotes, bacteria and archaea. Proteobacteria and Bacteroidetes were the dominant bacterial phyla. Archaea were also detected in sites where snow algae dominated and they mainly belong to the Nitrososphaerales, which are known as important ammonia oxidizers. Multivariate analyses indicated no relationships between nutrient data and microbial community structure. However, the aqueous geochemical simulations suggest that the microbial communities were not nutrient limited because of the equilibrium of snow with the nutrient-rich and fast dissolving volcanic ash. Increasing algal secondary carotenoid contents in the last stages of the melt seasons have previously been associated with a decrease in surface albedo, which in turn could potentially have an impact on the melt rates of Icelandic glaciers.

Microbial diversity on Icelandic glaciers and ice caps

PubMed Central

Lutz, Stefanie; Anesio, Alexandre M.; Edwards, Arwyn; Benning, Liane G.

2015-01-01

Algae are important primary colonizers of snow and glacial ice, but hitherto little is known about their ecology on Iceland's glaciers and ice caps. Due do the close proximity of active volcanoes delivering large amounts of ash and dust, they are special ecosystems. This study provides the first investigation of the presence and diversity of microbial communities on all major Icelandic glaciers and ice caps over a 3 year period. Using high-throughput sequencing of the small subunit ribosomal RNA genes (16S and 18S), we assessed the snow community structure and complemented these analyses with a comprehensive suite of physical-, geo-, and biochemical characterizations of the aqueous and solid components contained in snow and ice samples. Our data reveal that a limited number of snow algal taxa (Chloromonas polyptera, Raphidonema sempervirens and two uncultured Chlamydomonadaceae) support a rich community comprising of other micro-eukaryotes, bacteria and archaea. Proteobacteria and Bacteroidetes were the dominant bacterial phyla. Archaea were also detected in sites where snow algae dominated and they mainly belong to the Nitrososphaerales, which are known as important ammonia oxidizers. Multivariate analyses indicated no relationships between nutrient data and microbial community structure. However, the aqueous geochemical simulations suggest that the microbial communities were not nutrient limited because of the equilibrium of snow with the nutrient-rich and fast dissolving volcanic ash. Increasing algal secondary carotenoid contents in the last stages of the melt seasons have previously been associated with a decrease in surface albedo, which in turn could potentially have an impact on the melt rates of Icelandic glaciers. PMID:25941518

Meteorological Situations Favouring the Development of Dust Plumes over Iceland

NASA Astrophysics Data System (ADS)

Schepanski, K.; Szodry, K.

2017-12-01

The knowledge on mineral dust emitted at high latitudes is limited, but its impact on the polar environments is divers. Within a warming climate, dust emitted from regions in cold climates is expected to increase due to the retreat of the ice sheet and increasing melting rates. Therefore, and for its extensive impacts on different aspects of the climate system, a better understanding of the atmospheric dust life-cycle at high latitudes/cold climates in general, and the spatio-temporal distribution of dust sources in particular, are essential. At high-latitudes, glacio-fluvial sediments as found on river flood plains e.g. supplied by glaciers are prone to wind erosion when dry and bare. In case of the occurrence of strong winds, sediments are blown out and dust plumes develop. As dust uplift is controlled by soil surface characteristics, the availability of suitable sediments, and atmospheric conditions, an interannual variability in dust source activity is expected. We investigated atmospheric circulation patterns that favour the development of dust plumes over Iceland, which presents a well-known dust source at high latitudes. Using the atmosphere model COSMO (COnsortium for Small-scale MOdeling), we analysed the wind speed distribution over the Iceland region for identified and documented dust cases. As one outcome of the study, the position of the Icelandic low, the anticyclones located over Northern Europe, and the resulting pressure gradients are of particular relevance. The interaction of the synoptic-scale winds with the Icelandic orography may locally enhance the wind speeds and thus foster local dust emission. Results from this study suggest that the atmospheric circulation determined by the pressure pattern is of particular relevance for the formation of dust plumes entering the North Atlantic.

Breakup of the Larsen Ice Shelf, Antarctica

NASA Technical Reports Server (NTRS)

2002-01-01

Recent Moderate-resolution Imaging Spectroradiometer (MODIS) satellite imagery analyzed at the University of Colorado's National Snow and Ice Data Center revealed that the northern section of the Larsen B ice shelf, a large floating ice mass on the eastern side of the Antarctic Peninsula, has shattered and separated from the continent. This particular image was taken on March 5, 2002. The shattered ice formed a plume of thousands of icebergs adrift in the Weddell Sea. A total of about 3,250 square kilometers of shelf area disintegrated in a 35-day period beginning on January 31, 2002. Over the last five years, the shelf has lost a total of 5,700 square kilometers and is now about 40 percent the size of its previous minimum stable extent. Ice shelves are thick plates of ice, fed by glaciers, that float on the ocean around much of Antarctica. The Larsen B shelf was about 220 meters thick. Based on studies of ice flow and sediment thickness beneath the ice shelf, scientists believe that it existed for at least 400 years prior to this event and likely existed since the end of the last major glaciation 12,000 years ago. For reference, the area lost in this most recent event dwarfs Rhode Island (2,717 square kilometers) in size. In terms of volume, the amount of ice released in this short time is 720 billion tons--enough ice for about 12 trillion 10-kilogram bags. This is the largest single event in a series of retreats by ice shelves along the peninsula over the last 30 years. The retreats are attributed to a strong climate warming in the region. The rate of warming is approximately 0.5 degrees Celsius per decade, and the trend has been present since at least the late 1940s. Overall in the peninsula, the extent of seven ice shelves has declined by a total of about 13,500 square kilometers since 1974. This value excludes areas that would be expected to calve under stable conditions. Ted Scambos, a researcher with the National Snow and Ice Data Center (NSIDC) at

Seasonal and interannual cross-shelf transport over the Texas and Louisiana continental shelf

NASA Astrophysics Data System (ADS)

Thyng, Kristen M.; Hetland, Robert D.

2018-05-01

Numerical drifters are tracked in a hydrodynamic simulation of circulation over the Texas-Louisiana shelf to analyze patterns in cross-shelf transport of materials. While the important forcing mechanisms in the region (wind, river, and deep eddies) and associated flow patterns are known, the resultant material transport is less well understood. The primary metric used in the calculations is the percent of drifters released within a region that cross the 100 m isobath. Results of the analysis indicate that, averaged over the eleven years of the simulation, there are two regions on the shelf - over the Texas shelf during winter, and over the Louisiana shelf in summer - with increased seasonal probability for offshore transport. Among the two other distinct regions, the big bend region in Texas has increased probability for onshore transport, and the Mississippi Delta region has an increase in offshore transport, for both seasons. Some of these regions of offshore transport have marked interannual variability. This interannual variability is correlated to interannual changes in forcing conditions. Winter transport off of the Texas shelf is correlated with winter mean wind direction, with more northerly winds enhancing offshore transport; summer transport off the Louisiana shelf is correlated with Mississippi River discharge.

Petrography and petrology of the Nornahraun eruption of the Bárðarbunga volcanic system, Iceland

NASA Astrophysics Data System (ADS)

Guðfinnsson, Guðmundur H.; Halldórsson, Sæmundur Ari; Bali, Enikő; Jakobsson, Sigurður; Sverrisdóttir, Guðrún; Höskuldssson, Ármann; Riishuus, Morten S.; Þórðarson, Þorvaldur; The 2014 Nornahraun Eruption Team

2015-04-01

The on-going fissure eruption north of Dyngjujökull is becoming the largest of its kind in Iceland since the 1783-84 Laki eruption. The erupted lava is olivine tholeiite, containing up to 5% normative olivine. It is relatively macrocryst-poor, initially containing less than 1% phenocrysts by volume, increasing to over 1% as the eruption has progressed. Plagioclase is the dominant macrocryst phase but olivine and augite are also present. In most of the samples, crystallization of the groundmass is substantial, with plagioclase and augite as the key groundmass minerals and minor olivine. It features subophitic texture, typical for olivine tholeiites, where the interstitial glass contains dendritic Fe-Ti oxide. During the first two months of the eruption, magma composition has been constant, displaying uniform major and trace element composition and nearly uniform isotopic compositions (Halldórsson et al. (a), this session). The major and trace element contents, in addition to the isotope ratios of lead, are indistinguishable from basalts in the Bárðarbunga volcanic system (Halldórsson et al. (b), this session). The compositional trends are consistent with crystallization along the ol-plag-cpx cotectic. Crystallization depth estimates, based on the pressure dependence of the cotectic (Yang et al., 1996), indicate that the magma equilibrated at a minimum depth between 6-9 km, consistent with depth estimates derived from CO2-bearing fluid inclusions trapped in plagioclase phenocrysts (Bali et al., this session). The bulk of the earthquakes associated with this volcano-tectonic episode are also in this range (e.g., Sigmundsson et al., 2015). Calculations with several different magma geothermometers suggest that the temperature of the magma as it rises to the surface is about 1170-1180°C, in good agreement with on-site measurements by thermal imaging cameras. The eruption has been characterized by steady, high emission of SO2. The sulfur-rich nature of the lava is

Privatization of Early Childhood Education in Iceland

ERIC Educational Resources Information Center

Dýrfjörð, Kristín; Magnúsdóttir, Berglind Rós

2016-01-01

The overall aim of this paper is to give a comprehensive picture of the marketization of early childhood education in Iceland. Our theoretical framework is based on Hursh's (2007) analysis of how the governance of schools is reshaped to serve a neoliberal agenda with the help of internal and external privatization (Ball and Youdell, 2007). In this…

Comparison of Campylobacter jejuni isolates from human, food, veterinary and environmental sources in Iceland using PFGE, MLST and fla-SVR sequencing.

PubMed

Magnússon, S H; Guðmundsdóttir, S; Reynisson, E; Rúnarsson, A R; Harðardóttir, H; Gunnarson, E; Georgsson, F; Reiersen, J; Marteinsson, V Th

2011-10-01

Campylobacter jejuni isolates from various sources in Iceland were genotyped with the aim of assessing the genetic diversity, population structure, source distribution and campylobacter transmission routes to humans. A collection of 584 Campylobacter isolates were collected from clinical cases, food, animals and environment in Iceland in 1999-2002, during a period of national Campylobacter epidemic in Iceland. All isolates were characterized by pulse field gel electrophoresis (PFGE), and selected subset of 52 isolates representing the diversity of the identified PFGE types was further genotyped using multilocus sequence typing (MLST) and fla-SVR sequencing to gain better insight into the population structure. The results show a substantial diversity within the Icelandic Campylobacter population. Majority of the human Campylobacter infections originated from domestic chicken and cattle isolates. MLST showed the isolates to be distributed among previously reported and common sequence type complexes in the MLST database. The genotyping of Campylobacter from various sources has not previously been reported from Iceland, and the results of the study gave a valuable insight into the population structure of Camp. jejuni in Iceland, source distribution and transmission routes to humans. The geographical isolation of Iceland in the north Atlantic provides new information on Campylobacter population dynamics on a global scale. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology No claim to Icelandic Government works.

The temperature of the Icelandic mantle from olivine-spinel aluminum exchange thermometry

NASA Astrophysics Data System (ADS)

Matthews, S.; Shorttle, O.; Maclennan, J.

2016-11-01

New crystallization temperatures for four eruptions from the Northern Volcanic Zone of Iceland are determined using olivine-spinel aluminum exchange thermometry. Differences in the olivine crystallization temperatures between these eruptions are consistent with variable extents of cooling during fractional crystallization. However, the crystallization temperatures for Iceland are systematically offset to higher temperatures than equivalent olivine-spinel aluminum exchange crystallization temperatures published for MORB, an effect that cannot be explained by fractional crystallization. The highest observed crystallization temperature in Iceland is 1399 ± 20°C. In order to convert crystallization temperatures to mantle potential temperature, we developed a model of multilithology mantle melting that tracks the thermal evolution of the mantle during isentropic decompression melting. With this model, we explore the controls on the temperature at which primary melts begin to crystallize, as a function of source composition and the depth from which the magmas are derived. Large differences (200°C) in crystallization temperature can be generated by variations in mantle lithology, a magma's inferred depth of origin, and its thermal history. Combining this model with independent constraints on the magma volume flux and the effect of lithological heterogeneity on melt production, restricted regions of potential temperature-lithology space can be identified as consistent with the observed crystallization temperatures. Mantle potential temperature is constrained to be 1480-30+37 °C for Iceland and 1318-32+44 °C for MORB.

Holland in Iceland revisited: an emic approach to evaluating U.S. vocational interest models.

PubMed

Einarsdóttir, Sif; Rounds, James; Su, Rong

2010-07-01

An emic approach was used to test the structural validity and applicability of Holland's (1997) RIASEC (Realistic, Investigative, Artistic, Social, Enterprising, Conventional) model in Iceland. Archival data from the development of the Icelandic Interest Inventory (Einarsdóttir & Rounds, 2007) were used in the present investigation. The data included an indigenous pool of occupations and work-task items representing Iceland's world of work that had been administered to a sample of 597 upper secondary school students. Multidimensional scaling analysis and property vector fitting using Prediger's (1981) work-task dimensions were applied to the item responses to test if the RIASEC model could be identified. The results indicated that a 4-dimensional solution better explains the interest space in Iceland than Holland's 2-dimensional RIASEC representation. The work-task dimension of People-Things and the Sex-Type and Prestige dimensions were located in the 1st and 2nd dimensions of the multidimensional scaling solution, but Data-Ideas, a dimension critical to the RIASEC model, was not. The 3rd and 4th dimensions did not correspond to any dimensions previously detected in structural studies in the United States and seem to be related to specific ecological, cultural, and political forces in Iceland. These results demonstrate the importance of selecting representative indigenous occupations and work tasks when evaluating the RIASEC model. The present study is an example of the next step in a comprehensive cross-cultural research program on vocational interests, an emic investigation. (c) 2010 APA, all rights reserved.

Integrating volcanic gas monitoring with other geophysical networks in Iceland

NASA Astrophysics Data System (ADS)

Pfeffer, Melissa A.

2017-04-01

The Icelandic Meteorological Office/Icelandic Volcano Observatory is rapidly developing and improving the use of gas measurements as a tool for pre- and syn-eruptive monitoring within Iceland. Observations of deformation, seismicity, hydrological properties, and gas emissions, united within an integrated approach, can provide improved understanding of subsurface magma movements. This is critical to evaluate signals prior to and during volcanic eruptions, issue timely eruption warnings, forecast eruption behavior, and assess volcanic hazards. Gas measurements in Iceland need to be processed to account for the high degree of gas composition alteration due to interaction with external water and rocks. Deeply-sourced magmatic gases undergo reactions and modifications as they move to the surface that exercise a strong control on the composition of surface emissions. These modifications are particularly strong at ice-capped volcanoes where most surface gases are dissolved in glacial meltwater. Models are used to project backwards from surface gas measurements to what the magmatic gas composition was prior to upward migration. After the pristine magma gas composition has been determined, it is used together with fluid compositions measured in mineral hosted melt inclusions to calculate magmatic properties to understand magma storage and migration and to discern if there have been changes in the volcanic system. The properties derived from surface gas measurements can be used as input to models interpreting deformation and seismic observations, and can be used as an additional, independent observation when interpreting hydrological and seismic changes. An integrated approach aids with determining whether observed hydro/geological changes can be due to the presence of shallow magma. Constraints on parameters such as magma gas content, viscosity and compressibility can be provided by the approach described above, which can be utilized syn-eruptively to help explain

Formation and Cultural Use of Wetland Areas in Vatnsfjörður, Northwest Iceland

NASA Astrophysics Data System (ADS)

Barclay, Rebecca; Simpson, Ian; Tisdall, Eileen

2013-04-01

Because of their development in-situ over extended time periods, Histosols are an important record of the intimate relationship between societal and environmental change. In this paper we offer new insights into land management adaptations as Norse settlers arrived and colonised the previously pristine landscapes of Iceland. Our Histosol record from Vatnsfjörður, NW Iceland is chronologically constrained through a combination of tephrochronology and radiocarbon measurement, and is associated with a tenth century long house and subsequent settlement into the medieval period as the locality emerged as one of the richest by the late Icelandic middle ages. Integration of field survey, thin section micromorphology and pollen analyses of histosols together with documentary records indicates the first evidence of artificially created wet meadows in Iceland, developed to give sustained fodder production for over-wintering livestock in an environment that inherently had a short growing season and lacked soil fertility. The findings have wider implications for understanding the emergence of resilient and sustainable communities in agriculturally marginal environments.

Shelf-life dating of shelf-stable strawberry juice based on survival analysis of consumer acceptance information.

PubMed

Buvé, Carolien; Van Bedts, Tine; Haenen, Annelien; Kebede, Biniam; Braekers, Roel; Hendrickx, Marc; Van Loey, Ann; Grauwet, Tara

2018-07-01

Accurate shelf-life dating of food products is crucial for consumers and industries. Therefore, in this study we applied a science-based approach for shelf-life assessment, including accelerated shelf-life testing (ASLT), acceptability testing and the screening of analytical attributes for fast shelf-life predictions. Shelf-stable strawberry juice was selected as a case study. Ambient storage (20 °C) had no effect on the aroma-based acceptance of strawberry juice. The colour-based acceptability decreased during storage under ambient and accelerated (28-42 °C) conditions. The application of survival analysis showed that the colour-based shelf-life was reached in the early stages of storage (≤11 weeks) and that the shelf-life was shortened at higher temperatures. None of the selected attributes (a * and ΔE * value, anthocyanin and ascorbic acid content) is an ideal analytical marker for shelf-life predictions in the investigated temperature range (20-42 °C). Nevertheless, an overall analytical cut-off value over the whole temperature range can be selected. Colour changes of strawberry juice during storage are shelf-life limiting. Combining ASLT with acceptability testing allowed to gain faster insight into the change in colour-based acceptability and to perform shelf-life predictions relying on scientific data. An analytical marker is a convenient tool for shelf-life predictions in the context of ASLT. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Seismic unrest at Katla Volcano- southern Iceland

NASA Astrophysics Data System (ADS)

jeddi, zeinab; Tryggvason, Ari; Gudmundsson, Olafur; Bödvarsson, Reynir; SIL Seismology Group

2014-05-01

Katla volcano is located on the propagating Eastern Volcanic Zone (EVZ) in South Iceland. It is located beneath Mýrdalsjökull ice-cap which covers an area of almost 600 km2, comprising the summit caldera and the eruption vents. 20 eruptions between 930 and 1918 with intervals of 13-95 years are documented at Katla which is one of the most active subglacial volcanoes in Iceland. Eruptions at Katla are mainly explosive due to the subglacial mode of extrusion and produce high eruption columns and catastrophic melt water floods (jökulhlaups). The present long Volcanic repose (almost 96 years) at Katla, the general unrest since 1955, and the 2010 eruption of the neighbouring Eyjafjallajökull volcano has prompted concerns among geoscientists about an imminent eruption. Thus, the volcano has been densely monitored by seismologists and volcanologists. The seismology group of Uppsala University as a partner in the Volcano Anatomy (VA) project in collaboration with the University of Iceland and the Icelandic Meteorological Office (IMO) installed 9 temporary seismic stations on and around the Mýrdalsjökull glacier in 2011. Another 10 permanent seismic stations are operated by IMO around Katla. The project's data collection is now finished and temporary stations were pulled down in August 2013. According to seismicity maps of the whole recording period, thousands of microearthquakes have occurred within the caldera region. At least three different source areas are active in Katla: the caldera region, the western Godaland region and a small cluster at the southern rim of Mýrdalsjökull near the glacial stream of Hafursarjökull. Seismicity in the southern flank has basically started after June 2011. The caldera events are mainly volcano-tectonic, while western and southern events are mostly long period (lp) and can be related to glacial or magmatic movement. One motivation of the VA Katla project is to better understand the physical mechanism of these lp events. Changes

Ridge-transform interaction and seismic behavior within the Tjörnes Fracture Zone, N-Iceland

NASA Astrophysics Data System (ADS)

Brandsdottir, B.; Magnusdottir, S.; Einarsson, P.; Gudmundsson, G.; Detrick, R. S.; Driscoll, N. W.

2013-12-01

High-resolution multibeam bathymetry and chirp profiling data have provided a new perspective on the structure and neotectonics of the onland-offshore Húsavík-Flatey Fault System (HFF) within the Tjörnes Fracture Zone (TFZ), N-Iceland. The TFZ comprises a broad right lateral transform zone made up of three major N-S striking extensional basins and three WNW-striking seismic lineaments, the dextral HFF, the Grímsey Oblique Rift Zone (GRZ) and the Dalvík Fault System (DF). The HFF connects the North Iceland Rift Zone (NIRZ) with the Eyjafjardaráll extensional basin (EB), the magma starved southern extension of the Kolbeinsey Ridge (KR) whereas the GRZ constitutes the offshore extension of the NIRZ with the KR. The HFF has an overall trend of N65°W and can be traced 75-80 km from its eastern junction with the NIRZ, across the Skjálfandi Bay and into the Eyjafjardaráll basin. Four pull-apart basins characterize the HFF, the largest at its intersection with the EB. En echelon arrays of conjugate strike-slip faults intersect the main HFF at angles of N20°-30°W and N20°E. Some can be traced onto land where they exhibit complicated flower patterns. Within the Skjálfandi Bay, the HFF is divided into two main branches, separated by a 70 m high N-S aligned push-up ridge and several smaller, sub-parallel WNW-trending faults. Individual fault strands have vertical displacement from 0-15 m. Large earthquakes occurred along the HFF in 1755, 1867, 1872 and 1884, the GRZ in 1884-1885 and 1910 and on the DF in 1838, 1934 and 1963. Some were destructive. A dextral transform offshore N-Iceland was initially based on diffuse earthquake epicenters and the M7, 1963 Skagafjördur earthquake. Data from the analog Iceland seismic network, established in the early 1970s, showed the TFZ microseismicity to be too diffuse to be associated with a simple oceanic transform fault. Recent seismicity within the TFZ consists of frequent earthquake swarms, lasting days or weeks with a

Solar radiation in Iceland

NASA Astrophysics Data System (ADS)

Ólafsson, Haraldur; Cataldi, Maxime; Zehouf, Hafsa; Pálmason, Bolli

2014-05-01

Short wave radiation has been observed at several locations in Iceland in recent years. The observations reveal that there is large spatial variability in the incoming radiation. There are indications of a coast-to-inland gradient and there is much greater radiation at central-inland locations than further west as well in the far east. The results are in line with Markús Á. Einarsson's reports where estimation of radiation was based on manned cloud observations shortly after the middle of the 20th century. Values of radiation retrieved from the operational simulations of the European Centre for Medium-range Weather Forecasts (ECMWF) compare in general well with the observations.

The impact of economic factors on migration considerations among Icelandic specialist doctors: a cross-sectional study.

PubMed

Solberg, Ingunn Bjarnadóttir; Tómasson, Kristinn; Aasland, Olaf; Tyssen, Reidar

2013-12-18

Globalization has facilitated the employability of doctors almost anywhere in the world. In recent years, the migration of doctors seems to have increased. However, we lack studies on doctors' migration from developed countries. Because the economic recession experienced by many countries might have affected the migration of doctors, research on this topic is important for the retention of doctors. Iceland was hit hard by the economic recession in 2008. Therefore, we want to explore how many specialist doctors in Iceland have considered migrating and whether economic factors at work and in private life, such as extensive cost-containment initiatives at work and worries about personal finances, are related to doctors' migration considerations. In 2010, all doctors in Iceland registered with the Icelandic Medical Association were sent an electronic cross-sectional survey by email. The 467 specialists who participated in this study represent 55% of all specialist doctors working in Iceland. Information on doctors' contemplation of migration was available from responses to the question: "Have you considered moving and working abroad?" The predictor variables in our logistic regression model are perceived cost-containment initiatives at work, stress related to personal finances, experience of working abroad during vacations, job dissatisfaction, job position, age, and gender. Sixty-three per cent of Iceland's specialist doctors had considered relocation abroad, 4% were moving in the next year or two, and 33% had not considered relocating. Logistic regression analysis shows that, controlling for age, gender, job position, job satisfaction, and experience of working abroad during vacations, doctors' migration considerations were significantly affected by their experiences of cost-containment initiatives at work (odds ratio (OR) = 2.0, p < 0.01) and being stressed about personal finances (OR = 1.6, p < 0.001). Age, job satisfaction, and working abroad

Cereal production, high status and climate in Medieval Iceland

NASA Astrophysics Data System (ADS)

Erlendsson, Egill; Riddell, Scott

2017-04-01

At Hrísbrú (formerly the medieval Mosfell estate) in the Mosfell Valley, southwest Iceland, archaeologists have excavated a medieval skáli (hall) proposed to be the high status residence of a chieftain. This is indicated by the size of the skáli, artefacts (foreign goods), archaeofaunal (cattle/sheep bone) ratios and macrobotanical remains (cereal grain). The analysis of pollen from nearby natural contexts suggests that cereals were grown locally. Using multiple profile palynological approach, this paper examines if the apparent cereal production is representative of high status in the Icelandic context. First as a correlate by confirming that cereals were grown in association with the archaeological features characteristic of high status; secondly, as an indicator in its own right through comparison with other palynological datasets from inferred lower status farms. The presence or absence of cereal-type pollen (cf. barley) and other arable correlates was examined for each site. The results suggest that medieval cereal cultivation in the Mosfell Valley was confined to the landholding of the medieval Mosfell estate. This feature is seen as an attribute of the locale's greater status in relation to the other farms in Mosfell Valley. The abandonment of cereal cultivation at the Mosfell estate around AD 1200 is probably associated with interactions between changes in the nation's social power structure and how marginal cereal production in Iceland was (and is) in terms of climate.

Local food in Iceland: identifying behavioral barriers to increased production and consumption

NASA Astrophysics Data System (ADS)

Ósk Halldórsdóttir, Þórhildur; Nicholas, Kimberly A.

2016-11-01

Increased production and consumption of local food may reduce the negative environmental, social, and economic impacts of industrialized and globalized food production. Here we examined potential barriers to increasing production and consumption of food produced in Iceland. First, we developed a new framework to address the behaviors of production and consumption simultaneously, to comprehensively analyze their potential barriers. We examined structural barriers by estimating the food production capacity of Iceland, and cultural and personal barriers through survey data on cultural norms and purchasing behavior from Matís, a research and development company. We found no structural barriers preventing Iceland from increasing production of local cereals, which would compliment current local production of meat and dairy and reduce reliance on imports, currently at 50% of the daily caloric intake. However, if food production became entirely local without changing the current mix of crops grown, there would be a 50% reduction in diversity (from 50 to 25 items in eight out of ten food categories). We did not identify any cultural barriers, as survey results demonstrated that consumers hold generally positive worldviews towards local food, with 88% satisfied with local food they had purchased. More than two-thirds of consumers regarded supporting the local farmer and considerations such as environmentally friendly production, fewer food miles, lower carbon footprint as important. However, they rated the local food they have access to as lower in meeting sustainability criteria, showing that they make justifications for not choosing local food in practice. This is a personal barrier to increased consumption of local food, and implies that marketing strategies and general knowledge connected to local food in Iceland might be improved. Although the results apply to the case of Iceland, the method of identifying behavioral barriers to change is applicable to other countries

Ash plume from Eyjafjallajokull Volcano, Iceland May 6th View [Detail

NASA Image and Video Library

2017-12-08

NASA satellite image acquired May 6, 2010 at 11 :55 UTC To view the full view go to: www.nasa.gov/topics/earth/features/iceland-volcano-plume.... NASA Satellite Sees a Darker Ash Plume From Iceland Volcano NASA's Terra satellite flew over the Eyjafjallajokull Volcano, Iceland, on May 6 at 11:55 UTC (7:55 a.m. EDT). The Moderate Resolution Imaging Spectroradiometer instrument known as MODIS that flies onboard Terra, captured a visible image of the ash plume. The plume was blowing east then southeast over the Northern Atlantic. The satellite image shows that the plume is at a lower level in the atmosphere than the clouds that lie to its east, as the brown plume appears to slide underneath the white clouds. Satellite: Terra NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team To learn more about MODIS go to: rapidfire.sci.gsfc.nasa.gov/gallery/?latest NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Multigenerational information: the example of the Icelandic Genealogy Database.

PubMed

Tulinius, Hrafn

2011-01-01

The first part of the chapter describes the Icelandic Genealogical Database, how it was created, what it contains, and how it operates. In the second part, an overview of research accomplished with material from the database is given.

A chironomid-based reconstruction of summer temperatures in NW Iceland since AD 1650

NASA Astrophysics Data System (ADS)

Langdon, P. G.; Caseldine, C. J.; Croudace, I. W.; Jarvis, S.; Wastegård, S.; Crowford, T. C.

2011-05-01

Few studies currently exist that aim to validate a proxy chironomid-temperature reconstruction with instrumental temperature measurements. We used a reconstruction from a chironomid percentage abundance data set to produce quantitative summer temperature estimates since AD 1650 for NW Iceland through a transfer function approach, and validated the record against instrumental temperature measurements from Stykkishólmur in western Iceland. The core was dated through Pb-210, Cs-137 and tephra analyses (Hekla 1693) which produced a well-constrained dating model across the whole study period. Little catchment disturbance, as shown through geochemical (Itrax) and loss-on-ignition data, throughout the period further reinforce the premise that the chironomids were responding to temperature and not other catchment or within-lake variables. Particularly cold phases were identified between AD 1683-1710, AD 1765-1780 and AD 1890-1917, with relative drops in summer temperatures in the order of 1.5-2°C. The timing of these cold phases agree well with other evidence of cooler temperatures, notably increased extent of Little Ice Age (LIA) glaciers. Our evidence suggests that the magnitude of summer temperature cooling (1.5-2°C) was enough to force LIA Icelandic glaciers into their maximum Holocene extent, which is in accordance with previous modelling experiments for an Icelandic ice cap (Langjökull).

Piloting Technological Understanding and Reasoning in Icelandic Schools

ERIC Educational Resources Information Center

Thorsteinsson, Gisli; Olafsson, Brynjar

2016-01-01

A pilot research was undertaken in Icelandic schools during the 2013-2014 school year, in order to explore students' technological understanding and reasoning at the ages of 11 and 13. The survey included a questionnaire regarding mechanical movement, power and thermodynamics, while the project considered the congruity between students'…

Social Cognition and Social Anxiety among Icelandic Schoolchildren

ERIC Educational Resources Information Center

Hannesdottir, Dagmar Kr.; Ollendick, Thomas H.

2007-01-01

The primary purpose of this study is to examine relationships among social cognition, social anxiety, and social skills with friends and strangers in children. Ninety-two children (age 10-14 years) in Iceland completed questionnaires on social anxiety, social skills, assertiveness, self-efficacy, and outcome expectancy in social situations with…

Trichinella nativa in Iceland: an example of Trichinella dispersion in a frigid zone.

PubMed

Skírnisson, K; Marucci, G; Pozio, E

2010-06-01

In most Arctic and subarctic regions, Trichinella nativa is a common zoonotic pathogen circulating among wild carnivores. The polar bear (Ursus maritimus) is one of the most important reservoirs for T. nativa in frigid zones. In Iceland, Trichinella infection has never been detected in the local wildlife, despite the presence of one of the host species, the arctic fox (Alopex lagopus). In 2008, one of two polar bears that had swum to Iceland's coast was found to have been infected with Trichinella sp. (8.5 larvae/g in the tongue, 6.8 larvae/g in the masseter and 4.4 larvae/g in the diaphragm); the larvae were identified as T. nativa. This is the second report of Trichinella infection in polar bears that reached the Icelandic coast. In the present work, we describe this case of infection and discuss the epidemiological features that have allowed T. nativa to spread in Arctic regions.

Five 'Supercool' Icelandic Glaciers

NASA Astrophysics Data System (ADS)

Knudsen, O.; Roberts, M. J.; Roberts, M. J.; Tweed, F. S.; Russell, A. J.; Lawson, D. E.; Larson, G. J.; Evenson, E. B.; Bjornsson, H.

2001-12-01

Sediment entrainment by glaciohydraulic supercooling has recently been demonstrated as an effective process at Matanuska glacier, Alaska. Although subfreezing meltwater temperatures have been recorded at several Alaskan glaciers, the link between supercooling and sediment accretion remains confined to Matanuska. This study presents evidence of glaciohydraulic supercooling and associated basal ice formation from five Icelandic glaciers: Skeidarárjökull, Skaftafellsjökull, Kvíárjökull, Flaájökull, and Hoffellsjökull. These observations provide the best example to-date of glaciohydraulic supercooling and related sediment accretion outside Alaska. Fieldwork undertaken in March, July and August 2001 confirmed that giant terraces of frazil ice, diagnostic of the presence of supercooled water, are forming around subglacial artesian vents. Frazil flocs retrieved from these vents contained localised sandy nodules at ice crystal boundaries. During periods of high discharge, sediment-laden frazil flocs adhere to the inner walls of vents, and continue to trap suspended sediment. Bands of debris-rich frazil ice, representing former vents, are texturally similar to basal ice exposures at the glacier margins, implying a process-form relationship between glaciohydraulic freeze-on and basal ice formation. It is hypothesised that glaciohydraulic supercooling is generating thick sequences of basal ice. Observations also confirm that in situ melting of basal ice creates thick sedimentary sequences, as sediment structures present in the basal ice can be clearly traced into ice-marginal ridges. Glaciohydraulic supercooling is an effective sediment entrainment mechanism at Icelandic glaciers. Supercooling has the capacity to generate thick sequences of basal ice and the sediments present in basal ice can be preserved. These findings are incompatible with established theories of intraglacial sediment entrainment and basal ice formation; instead, they concur with, and extend, the

[Dermatitis in cats and humans caused by Cheyletiella mites reported in Iceland.].

PubMed

Skirnisson, K; Olafsson, J H; Finnsdottir, H

1997-01-01

Cheyletiella mites (Acarina) are ectoparasites that infest cats, dogs and rabbits in many countries of the world. Upon contact with infested animals the mites may temporarily produce grouped, erythematous macules on the skin of humans which rapidly develop a central, vesicular papule. These signs are most often found on the arms and the trunk. Recently these typical signs were observed on the skin of the members of two different Icelandic families which both kept a Persian cat. An examination for ectoparasites on the cats revealed that both were infested by Cheyletiellaparasitovorax. It is unknown how and when the parasite was transmitted to Iceland.

Lifecycle effects of a recession on health behaviors: Boom, bust, and recovery in Iceland.

PubMed

Ásgeirsdóttir, Tinna Laufey; Corman, Hope; Noonan, Kelly; Reichman, Nancy E

2016-03-01

This study uses individual-level longitudinal data from Iceland, a country that experienced a severe economic crisis in 2008 and substantial recovery by 2012, to investigate the extent to which the effects of a recession on health behaviors are lingering or short-lived and to explore trajectories in health behaviors from pre-crisis boom, to crisis, to recovery. Health-compromising behaviors (smoking, heavy drinking, sugared soft drinks, sweets, fast food, and tanning) declined during the crisis, and all but sweets continued to decline during the recovery. Health-promoting behaviors (consumption of fruit, fish oil, and vitamins/minerals and getting recommended sleep) followed more idiosyncratic paths. Overall, most behaviors reverted back to their pre-crisis levels or trends during the recovery, and these short-term deviations in trajectories were probably too short-lived in this recession to have major impacts on health or mortality. A notable exception is for binge drinking, which declined by 10% during the 2 crisis years, continued to fall (at a slower rate of 8%) during the 3 recovery years, and did not revert back to the upward pre-crisis trend during our observation period. These lingering effects, which directionally run counter to the pre-crisis upward trend in consumption and do not reflect price increases during the recovery period, suggest that alcohol is a potential pathway by which recessions improve health and/or reduce mortality. Copyright © 2015 Elsevier B.V. All rights reserved.

Structure and kinematics of segment-scale crustal accretion processes in Iceland and implications for analogous mid-ocean ridge systems

NASA Astrophysics Data System (ADS)

Siler, Drew Lorenz

2011-12-01

The sub-surface geologic structure of the crust is controlled by the magmatic and tectonic processes that construct the crust during plate spreading. As a result, geologic structure provides constraints on the processes that occur during plate spreading. The crust of the Skagi region of northern Iceland, where this study was focused, was accreted by magmatic construction to Iceland ˜7-10 Ma and subsequently glacially eroded, exhuming ˜1-3 km of structural relief. Continuous spreading-parallel and spreading-orthogonal mountain ranges expose the crust accreted at discrete spreading segments, the fundamental intervals upon which plate spreading and crustal accretion occur. As a result, Skagi is an ideal location to employ geologic structure analysis to study magmatic rifting processes. Within spreading segments structural patterns vary significantly between segment centers and distal fissure swarms. While segment centers are characterized by focused magmatic construction and km-scale sub-volcanic subsidence, fissure swarms are characterized by limited magmatic construction, minor sub-axial subsidence and lateral dike injection. Such along-strike variation indicates that both magma in the upper crust and gabbroic material in the lower crust must be redistributed along-strike within spreading segments during plate spreading. Material flow is directed from beneath segment centers towards distal fissure swarms. At the regional scale, each spreading segment is a structurally discrete interval of Iceland's Neovolcanic Zone. As a result of west-northwestward movement of Iceland relative to the Iceland hotspot, the rift zone axis has progressively relocated to the east-southeast with time, leaving a series of abandoned rift zones throughout western Iceland. A compilation of published K/Ar and 40Ar/39Ar age data and geologic data from across northern Iceland shows that rift relocation occurs via frequent (2-3 Ma), small-scale (˜20 km) rift propagations rather than rare, 100

Environmental mapping and monitoring of Iceland by remote sensing (EMMIRS)

NASA Astrophysics Data System (ADS)

Pedersen, Gro B. M.; Vilmundardóttir, Olga K.; Falco, Nicola; Sigurmundsson, Friðþór S.; Rustowicz, Rose; Belart, Joaquin M.-C.; Gísladóttir, Gudrun; Benediktsson, Jón A.

2016-04-01

Iceland is exposed to rapid and dynamic landscape changes caused by natural processes and man-made activities, which impact and challenge the country. Fast and reliable mapping and monitoring techniques are needed on a big spatial scale. However, currently there is lack of operational advanced information processing techniques, which are needed for end-users to incorporate remote sensing (RS) data from multiple data sources. Hence, the full potential of the recent RS data explosion is not being fully exploited. The project Environmental Mapping and Monitoring of Iceland by Remote Sensing (EMMIRS) bridges the gap between advanced information processing capabilities and end-user mapping of the Icelandic environment. This is done by a multidisciplinary assessment of two selected remote sensing super sites, Hekla and Öræfajökull, which encompass many of the rapid natural and man-made landscape changes that Iceland is exposed to. An open-access benchmark repository of the two remote sensing supersites is under construction, providing high-resolution LIDAR topography and hyperspectral data for land-cover and landform classification. Furthermore, a multi-temporal and multi-source archive stretching back to 1945 allows a decadal evaluation of landscape and ecological changes for the two remote sensing super sites by the development of automated change detection techniques. The development of innovative pattern recognition and machine learning-based approaches to image classification and change detection is one of the main tasks of the EMMIRS project, aiming to extract and compute earth observation variables as automatically as possible. Ground reference data collected through a field campaign will be used to validate the implemented methods, which outputs are then inferred with geological and vegetation models. Here, preliminary results of an automatic land-cover classification based on hyperspectral image analysis are reported. Furthermore, the EMMIRS project

Tidal Modulation of Ice-shelf Flow: a Viscous Model of the Ross Ice Shelf

NASA Technical Reports Server (NTRS)

Brunt, Kelly M.; MacAyeal, Douglas R.

2014-01-01

Three stations near the calving front of the Ross Ice Shelf, Antarctica, recorded GPS data through a full spring-neap tidal cycle in November 2005. The data revealed a diurnal horizontal motion that varied both along and transverse to the long-term average velocity direction, similar to tidal signals observed in other ice shelves and ice streams. Based on its periodicity, it was hypothesized that the signal represents a flow response of the Ross Ice Shelf to the diurnal tides of the Ross Sea. To assess the influence of the tide on the ice-shelf motion, two hypotheses were developed. The first addressed the direct response of the ice shelf to tidal forcing, such as forces due to sea-surface slopes or forces due to sub-ice-shelf currents. The second involved the indirect response of ice-shelf flow to the tidal signals observed in the ice streams that source the ice shelf. A finite-element model, based on viscous creep flow, was developed to test these hypotheses, but succeeded only in falsifying both hypotheses, i.e. showing that direct tidal effects produce too small a response, and indirect tidal effects produce a response that is not smooth in time. This nullification suggests that a combination of viscous and elastic deformation is required to explain the observations.

A viable microbial community in a subglacial volcanic crater lake, Iceland.

PubMed

Gaidos, Eric; Lanoil, Brian; Thorsteinsson, Thorsteinn; Graham, Andrew; Skidmore, Mark; Han, Suk-Kyun; Rust, Terri; Popp, Brian

2004-01-01

We describe a viable microbial community in a subglacial lake within the Grímsvötn volcanic caldera, Iceland. We used a hot water drill to penetrate the 300-m ice shelf and retrieved lake water and volcanic tephra sediments. We also acquired samples of borehole water before and after penetration to the lake, overlying glacial ice and snow, and water from a nearby subaerial geothermal lake for comparative analyses. Lake water is at the freezing point and fresh (total dissolved solids = 260 mg L(-1)). Detectable numbers of cells were found in samples of the lake water column and tephra sediments: 2 x 10(4) ml(-1) and 4 x 10(7) g(-1), respectively. Plate counts document abundant cold-adapted cultivable organisms in the lake water, but not in the borehole (before penetration) or glacial ice. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments amplified from genomic DNA extracted from Grímsvötn samples indicates that the lake community is distinct from the assemblages of organisms in borehole water (before penetration) and the overlying ice and snow. Sequencing of selected DGGE bands revealed that many sequences are highly similar to known psychrophilic organisms or cloned DNA from other cold environments. Significant uptake of 14C-labeled bicarbonate occurred in dark, low-temperature incubations of lake water samples, indicating the presence of autotrophs. Acetylene reduction assays under similar incubation conditions showed no significant nitrogen fixation potential by lake water samples. This may be a consequence of the inhibition of diazotrophy by nitrogen in the lake.

Needs and care of older people living at home in Iceland.

PubMed

Sigurdardottir, Sigurveig H; Sundstrom, Gerdt; Malmberg, Bo; Bravell, Marie Ernsth

2012-02-01

The Icelandic old-age care system is universal and the official goal is to support older people live independently for as long as possible. The aim of this study is to analyse living conditions and use of formal and informal care of older people in Iceland. The results are based on the new study ICEOLD, a telephone survey which included questions on social network, health, activities of daily living, and received support from the community and/or from relatives, neighbours, and friends. Almost half of the sample (47%) receives some kind of care, with 27% of them receiving only informal care, which is understood to mean that informal care is of great importance and families are the main providers of help. For hypothetical future long-term care, older people wish to be cared for in their homes, but those already in need of assistance prefer to be cared for in institutions. Caring relatives are the main providers of support to older people in their homes and it is important to provide them with suitable formal support when the care responsibility increases. As the care system in Iceland is now under reconstruction, the important contribution of informal carers must be recognised and taken into account when planning the care of older people.

Margolisiella islandica sp. nov. (Apicomplexa: Eimeridae) infecting Iceland scallop Chlamys islandica (Müller, 1776) in Icelandic waters.

PubMed

Kristmundsson, Árni; Helgason, Sigurður; Bambir, Slavko H; Eydal, Matthías; Freeman, Mark A

2011-11-01

Wild Iceland scallops Chlamys islandica from an Icelandic bay were examined for parasites. Queen scallops Aequipecten opercularis from the Faroe Islands and king scallops Pecten maximus and queen scallops from Scottish waters were also examined. Observations revealed heavy infections of eimeriorine parasites in 95-100% of C. islandica but not the other scallop species. All life stages in the apicomplexan reproduction phases, i.e. merogony, gametogony and sporogony, were present. Trophozoites and meronts were common within endothelial cells of the heart's auricle and two generations of free merozoites were frequently seen in great numbers in the haemolymph. Gamonts at various developmental stages were also abundant, most frequently free in the haemolymph. Macrogamonts were much more numerous than microgamonts. Oocysts were exclusively in the haemolymph; live mature oocysts contained numerous (>500) densely packed pairs of sporozoites forming sporocysts. Analysis of the 18S ribosomal DNA revealed that the parasite from C. islandica is most similar (97.7% identity) to an unidentified apicomplexan isolated from the haemolymph of the giant clam, Tridacna crocea, from Japan. Phylogenetic analyses showed that the novel sequence consistently grouped with the Tridacna sequence which formed a robust sister clade to the rhytidocystid group. We propose the name Margolisiella islandica sp. nov., referring to both type host and type locality. Copyright © 2011 Elsevier Inc. All rights reserved.

Mantle Convection beneath the Aegir Ridge, a Shadow in the Iceland Hotspot

NASA Astrophysics Data System (ADS)

Howell, S. M.; Ito, G.; Breivik, A. J.; Hanan, B. B.; Mjelde, R.; Sayit, K.; Vogt, P. R.

2012-12-01

The Iceland Hotspot has produced extensive volcanism spanning much of the ocean basin between Greenland and Norway, forming one of the world's largest igneous provinces. However, an apparent igneous "shadow" in hotspot activity is located at the fossil Aegir Ridge, which formed anomalously thin crust, despite this ridge being near the Iceland hotspot when it was active. The Aegir Ridge accommodated seafloor spreading northeast of present-day Iceland from the time of continental breakup at ~55 Ma until ~25 Ma, at which point spreading shifted west to the Kolbeinsey Ridge. To address the cause of the anomalously thin crust produced by the Aegir Ridge, we use three-dimensional numerical models to simulate the interaction between a mantle plume beneath the Iceland hotspot, rifting continental lithosphere, and the time-evolving North Atlantic ridge system. Two end-member hypotheses were investigated: (1) Material emanating from the Iceland mantle plume was blocked from reaching the Aegir Ridge by the thick lithosphere of the Jan Mayen Microcontinent as the Kolbeinsey Ridge began rifting it from Greenland at ~30 Ma, just east of the plume center; (2) Plume material was not blocked and did reach the Aegir Ridge, but had already experienced partial melting closer to the hotspot. This material was then unable to produce melt volumes at the Aegir Ridge comparable to those of pristine mantle. To test these hypotheses, we vary the volume flux and viscosity of the plume, and identify which conditions do and do not lead to the Aegir Ridge forming anomalously thin crust. Results show that the combination of plume material being drawn into the lithospheric channels beneath the Reykjanes Ridge and Kolbeinsey Ridge after their respective openings, and the impedance of plume flow by the Jan Mayen Microcontinent (hypothesis 1), can deprive the Aegir Ridge of plume influence. This leads to low crustal thicknesses that are comparable to those observed. We have yet to produce a model

Ozone is associated with cardiopulmonary and stroke emergency hospital visits in Reykjavík, Iceland 2003-2009.

PubMed

Carlsen, Hanne Krage; Forsberg, Bertil; Meister, Kadri; Gíslason, Thorarinn; Oudin, Anna

2013-04-08

Air pollution exposure is associated with hospital admissions and emergency room visits for cardiopulmonary disease and stroke. Iceland's capital area, Reykjavik, has generally low air pollution levels, but traffic and natural sources contribute to pollution levels. The objective of this study was to investigate temporal associations between emergency hospital visits and air pollutants ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM10) in the Icelandic capital area. We constructed a time series of the daily number of adults who visited the emergency room, or were acutely admitted for stroke or cardiorespiratory causes to Landspitali University Hospital 1 January 2003 - 31 December 2009 from the hospital in-patient register. We used generalized additive models assuming Poisson distribution, to analyze the daily emergency hospital visits as a function of the pollutant levels, and adjusted for meteorological variables, day of week, and time trend with splines. Daily emergency hospital visits increased 3.9% (95% confidence interval (CI) 1.7-6.1%) per interquartile (IQR) change in average O3 the same and two previous days. For females, the increase was 7.8% (95% CI 3.6-12.1) for elderly (70+), the increase was 3.9% (95% CI 0.6-7.3%) per IQR increase of NO2. There were no associations with PM10. We found an increase in daily emergency hospital visits associated with O3, indicating that low-level exposure may trigger cardiopulmonary events or stroke.

"Can Drama, through Icelandic Tales, Increase Children's Vocabulary"?

ERIC Educational Resources Information Center

Thorkelsdóttir, Rannveig Björk; Ragnarsdóttir, Ása Helga

2013-01-01

The article is based on a study, done by Ása Helga Ragnarsdóttir and Rannveig Björk Þorkelsdóttir in 2010-2011 were the authors explored the research question: Can drama, through Icelandic tales, increase children's vocabulary? Methodology of the study was quantitative approach (comparative research). Data was gathered through questionnaires and a…

Export of a Winter Shelf Phytoplankton Bloom at the Shelf Margin of Long Bay (South Atlantic Bight, USA)

NASA Astrophysics Data System (ADS)

Nelson, J.; Seim, H.; Edwards, C. R.; Lockhart, S.; Moore, T.; Robertson, C. Y.; Amft, J.

2016-02-01

A winter 2012 field study off Long Bay (seaward of Myrtle Beach, South Carolina) investigated exchange processes along the shelf margin. Topics addressed included mechanisms of nutrient input (upper slope to outer shelf), phytoplankton blooms and community characteristics (mid-to-outer shelf), and possible export of shelf bloom material (transport to and across the shelf break to the upper slope). Observations utilized three moorings (mid-shelf, shelf break, upper slope), two gliders and ship operations (repeat cruises with profiling, water sampling and towed body surveys) along with satellite SST and ocean color imagery and near-by NOAA buoy records. Here we focus on the late January to early February period, when a mid-shelf bloom of Phaeocystis globosa (which forms large gelatinous colonies) was transported to the shelf break. The presence of Phaeocystis colonies resulted in strong spiking in chlorophyll (chl) fluorescence profiles. A partitioning approach was adapted to estimate chl in colonies (spikes) and small forms (baseline signal) and to account for an apparent difference in measured in vivo fluorescence per unit chl (lower in colonies). Up to 40-50% of chl in the bloom (surface to bottom on the mid-shelf) was estimated to be in the colonies. In late January, there a pronounced seaward slumping of relatively dense mid-shelf water along the bottom under warmer surface water derived from the inshore edge of a broad jet of Gulf Stream water flowing southwestward along the upper slope. We describe the evolution of this event and the conditions which set up this mechanism for episodic near-bed transport of fresh bloom material produced on the shelf to the upper slope off Long Bay. Down-slope transport may have been enhanced in this case by the high phytoplankton biomass in gelatinous colonies, which appeared to be settling in the water column on the shelf prior to the transport event.

Large-scale whole-genome sequencing of the Icelandic population.

PubMed

Gudbjartsson, Daniel F; Helgason, Hannes; Gudjonsson, Sigurjon A; Zink, Florian; Oddson, Asmundur; Gylfason, Arnaldur; Besenbacher, Soren; Magnusson, Gisli; Halldorsson, Bjarni V; Hjartarson, Eirikur; Sigurdsson, Gunnar Th; Stacey, Simon N; Frigge, Michael L; Holm, Hilma; Saemundsdottir, Jona; Helgadottir, Hafdis Th; Johannsdottir, Hrefna; Sigfusson, Gunnlaugur; Thorgeirsson, Gudmundur; Sverrisson, Jon Th; Gretarsdottir, Solveig; Walters, G Bragi; Rafnar, Thorunn; Thjodleifsson, Bjarni; Bjornsson, Einar S; Olafsson, Sigurdur; Thorarinsdottir, Hildur; Steingrimsdottir, Thora; Gudmundsdottir, Thora S; Theodors, Asgeir; Jonasson, Jon G; Sigurdsson, Asgeir; Bjornsdottir, Gyda; Jonsson, Jon J; Thorarensen, Olafur; Ludvigsson, Petur; Gudbjartsson, Hakon; Eyjolfsson, Gudmundur I; Sigurdardottir, Olof; Olafsson, Isleifur; Arnar, David O; Magnusson, Olafur Th; Kong, Augustine; Masson, Gisli; Thorsteinsdottir, Unnur; Helgason, Agnar; Sulem, Patrick; Stefansson, Kari

2015-05-01

Here we describe the insights gained from sequencing the whole genomes of 2,636 Icelanders to a median depth of 20×. We found 20 million SNPs and 1.5 million insertions-deletions (indels). We describe the density and frequency spectra of sequence variants in relation to their functional annotation, gene position, pathway and conservation score. We demonstrate an excess of homozygosity and rare protein-coding variants in Iceland. We imputed these variants into 104,220 individuals down to a minor allele frequency of 0.1% and found a recessive frameshift mutation in MYL4 that causes early-onset atrial fibrillation, several mutations in ABCB4 that increase risk of liver diseases and an intronic variant in GNAS associating with increased thyroid-stimulating hormone levels when maternally inherited. These data provide a study design that can be used to determine how variation in the sequence of the human genome gives rise to human diversity.

Larsen Ice Shelf, Antarctica

NASA Technical Reports Server (NTRS)

2002-01-01

Warmer surface temperatures over just a few months in the Antarctic can splinter an ice shelf and prime it for a major collapse, NASA and university scientists report in the latest issue of the Journal of Glaciology. Using satellite images of tell-tale melt water on the ice surface and a sophisticated computer simulation of the motions and forces within an ice shelf, the scientists demonstrated that added pressure from surface water filling crevasses can crack the ice entirely through. The process can be expected to become more widespread if Antarctic summer temperatures increase. This true-color image from Landsat 7, acquired on February 21, 2000, shows pools of melt water on the surface of the Larsen Ice Shelf, and drifting icebergs that have split from the shelf. The upper image is an overview of the shelf's edge, while the lower image is displayed at full resolution of 30 meters (98 feet) per pixel. The labeled pond in the lower image measures roughly 1.6 by 1.6 km (1.0 x 1.0 miles). Full text of Press Release More Images and Animations Image courtesy Landsat 7 Science Team and NASA GSFC

Along-shelf current variability on the Catalan inner-shelf (NW Mediterranean)

USGS Publications Warehouse

Grifoll, Manel; Aretxabaleta, Alfredo L.; Espino, Manuel; Warner, John C.

2012-01-01

We examine the circulation over the inner shelf of the Catalan Sea using observations of currents obtained from three ADCPs within the inner-shelf (24 and 50 m depth) during March-April 2011. The along-shelf current fluctuations during that period are mainly controlled by the local wind stress on short time scales and by remote pressure gradients on synoptic time scales. Different forcing mechanisms are involved in the along-shelf momentum balance. During storm conditions, wind stress, sea level gradients and the non-linear terms dominate the balance. During weak wind conditions, the momentum balance is controlled by the pressure gradient, while during periods of moderate wind in the presence of considerable stratification, the balance is established between the Coriolis and wind stress terms. Vertical variations of velocity are affected by the strong observed density gradient. The increased vertical shear is accompanied by the development of stratified conditions due to local heating when the wind is not able to counteract (and destroy) stratification. The occasional influence of the Besòs river plume is observed in time scales of hours to days in a limited area in front of Barcelona. The area affected by the plume depends on the vertical extend of the fresher layer, the fast river discharge peak, and the relaxation of cross-shore velocities after northeast storm events. This contribution provides a first interpretation of the inner-shelf dynamics in the Catalan Sea.

Grain size distribution and characteristics of the tephra from the Vatnaöldur AD 871±2 eruption, Iceland.

NASA Astrophysics Data System (ADS)

Jónsdóttir, Tinna; Larsen, Guðrún; Guðmundsson, Magnús

2014-05-01

Basaltic explosive eruptions in Iceland are frequent and often occur from vents in regions of surface lakes, large groundwater reservoirs or within glaciers. The recent Eyjafjallajökull eruption in 2010 and Grímsvötn eruption 2011 highlighted the vulnerability of passenger jet aircraft to ash in the atmosphere. Iceland's volcanoes are the most potent producers of tephra in Europe, and the frequent occurrence of basaltic explosive eruptions is a major factor in causing this. As a step in increasing the knowledge on the tephra erupted in basaltic explosive eruptions, we study the grain size distribution of a large (~5 km3) explosive basaltic eruption that occurred in AD 871±2. The source is the 25 km long Vatnaöldur crater row in south-central Iceland. The crater row lies within the Bárðarbunga-Veiðivötn volcanic system, one of the most productive volcanic systems in Iceland in recent times. Samples for grain size analysis were collected at six different locations along the broad northwest-trending dispersal axis. Sampling sites ranged in 1.5 km to 120 km distance from the largest vent Skyggnir, near the southern end of the crater row. The Vatnaöldur eruption has been classified as phreatomagmatic, erupting through fractured bedrock composed of recent lavas, hyaloclastites and pillow lava in an area characterized by a high groundwater level and surface lakes. Explosive activity dominanted the ~ 25 km long discontinuous fissure, as tuff cones were formed and conduits reached under groundwater table. During the eruption the tephra layer was dispersed in all directions. The area within the 0.5 cm isopach is 50,000 km2 and this tephra has also been identified in Greenland ice cores. The grain size analysis indicates that one dominant characteristic of the tephra is the scarcity of pyroclasts over 1 mm in diameter. In the ash sampled more than 4 km from source larger grain sizes are absent. The dispersion in the more distal parts, at distances of 60 - 120 km is

Influence of the Iceland mantle plume on North Atlantic continental margins

NASA Astrophysics Data System (ADS)

White, R. S.; Isimm Team

2003-04-01

Early Tertiary breakup of the North Atlantic was accompanied by widespread magmatism. The histories of the Iceland mantle plume, of rifting and of magmatism are intimately related. The magmatism provides a challenge both to imaging structure, and to modelling the subsidence and development of the continental margins. We report new work which integrates state-of-the-art seismic imaging and new acquisition on the Atlantic volcanic margins with new techniques for modelling their evolution. We discuss the distribution of igneous rocks along the North Atlantic margins and discuss the temporal and spatial variations in the Iceland mantle plume in the early Tertiary, which have largely controlled this pattern of magmatism. Igneous rocks are added to the crust on rifted margins as extrusive lavas, as sills intruded into the sub-surface and as lower crustal intrusions or underplate. Each provide different, but tractable problems to seismic imaging. We show that many of these difficulties can be surmounted by using very long offsets (long streamers or two-ship methods) with a broad-band, low-frequency source, and by using fixed ocean bottom receivers. We report results from surveys on the North Atlantic continental margins using these methods. Imaging results are shown from the recent FLARE project and from the iSIMM project, which recorded new seismic data recorded in summer 2002. The iSIMM project acquired two seismic surveys, using 85 4-component ocean bottom seismometers with long streamers for wide-angle data, and vertical arrays for far-field source signature recording. One survey crosses the Faroes Shelf and adjacent continental margin, and a second the Hatton-Rockall Basin, Hatton Bank and adjacent oceanic crust. The Faroes wide-angle profiles were overshot by WesternGeco's Topaz using three single-sensor, Q-Marine streamers, 12km plus two 4km. We designed deep-towed, broad-band low-frequency sources tuned to enhance the bubble pulses, with peak frequencies at 8

Small domes on Venus: Probable analogs of Icelandic lava shields

USGS Publications Warehouse

Garvin, James B.; Williams, Richard S.

1990-01-01

On the basis of observed shapes and volumetric estimates, we interpret small, dome-like features on radar images of Venus to be analogs of Icelandic lava-shield volcanoes. Using morphometric data for venusian domes in Aubele and Slyuta (in press), as well as our own measurements of representative dome volumes and areas from Tethus Regio, we demonstrate that the characteristic aspect ratios and flank slopes of these features are consistent with a subclass of low Icelandic lava-shield volcanoes (LILS ). LILS are slightly convex in cross-section with typical flank slopes of ∼3°. Plausible lava-shield-production rates for the venusian plains suggest formation of ∼53 million shields over the past 0.25 Ga. The cumulative global volume of lava that would be associated with this predicted number of lava shields is only a factor of 3–4 times that of a single oceanic composite shield volcano such as Mauna Loa. The global volume of all venusian lava shields in the 0.5–20-km size range would only contribute a meter of resurfacing over geologically significant time scales. Thus, venusian analogs to LILS may represent the most abundant landform on the globally dominant plains of Venus, but would be insignificant with regard to the global volume of lava extruded. As in Iceland, associated lavas from fissure eruptions probably dominate plains volcanism and should be evident on the higher resolution Magellan radar images.

Low prevalence of hepatitis E in Iceland: a seroepidemiological study.

PubMed

Löve, Arthur; Björnsdottir, Thora B; Olafsson, Sigurdur; Björnsson, Einar S

2018-03-01

Hepatitis E virus (HEV) infection has been reported to be more prevalent in the developed countries than previously thought. HEV infection is an important differential diagnosis in patients with drug-induced liver injury (DILI). The prevalence of hepatitis E was investigated in the general population of Iceland, among pig farmers and patients with DILI. Serum samples were tested for hepatitis E IgG, with two commercial ELISA tests: Diagnostic Bioprobes Srl. (Dia Pro) and the Wantai HEV IgG and subjects repeatedly reactive were tested with an immunoblot assay (RecomLINE). Three groups were tested: (1) healthy volunteers (HV), (2) pig farm workers (PFWs) and (3) patients participating in a nationwide prospective study on DILI. Overall 291 individuals were tested, HV (n = 195), PFW (n = 21) and DILI (n = 75). Only 6/291 (2.1%) tested positive for IgG antibodies to HEV in all three tests. Three HV were HEV IgG antibody positive and three in the DILI group. One PFW tested positive in the Dia Pro and Wantai tests but not in the immunoblot assay. All but one of the positive individuals in all three tests was either of foreign national origin or had spent extended period of time outside of Iceland. The seroprevalence of hepatitis E appears to be lower in Iceland than majority of recent studies in other western countries have demonstrated. This may be due to relative isolation and severe restriction on import of livestock from other countries.

Volcanic systems of Iceland and their magma source

NASA Astrophysics Data System (ADS)

Sigmarsson, Olgeir

2017-04-01

Several active hot-spot volcanoes produce magma from mantle sources which composition varies on decadal time scale. This is probably best demonstrated by the recent work of Pietruszka and collaborators on Kilauea, Hawaii. In marked contrast, basalt lavas from volcanic system in Iceland located above the presumed centre of the Iceland mantle plume have uniform isotope composition over the last 10 thousand years. Volcanic systems are composed of a central volcano and a fissure swarm, or a combination of both and they represent a fundamental component of the neovolcanic zones in Iceland. Four such systems, those of Askja, Bárðarbunga, Kverkfjöll and Grímsvötn in central Iceland were chosen for investigation. The last three have central volcanoes covered by the Vatnajökull ice-sheet whereas part of their fissure swarms is ice-free. Tephra produced during subglacial eruptions together with lavas from the fissure swarms of Holocene age have been collected and analysed for Sr, Nd and Th isotope ratios. Those volcanic formations that can be univocally correlated to a given volcanic system display uniform isotope ratio but different from one volcanic system to another. An exception to this regularity is that Askja products have isotope ratios indistinguishable from those of Gímsvötn, but since these volcanic systems lies far apart their lava fields do not overlap. A practical aspect of these findings was demonstrated during the rifting event of Bárðarbunga and fissure eruption forming the Holuhraun lava field. Relatively low, O isotope ratios in these basalts and heterogeneous macrocrystal composition have been ascribed to important metabasaltic crustal contamination with or without crystal mush recycling. In that case a surprisingly efficient magma mixing and melt homogenization must have occurred in the past beneath the volcanic systems. One possibility is that during the rapid deglaciation much mantle melting occurred and melts accumulated at the mantle

Larsen B Ice Shelf

Atmospheric Science Data Center

2013-04-16

article title:  Unique Views of a Shattered Ice Shelf     View Larger Image ... views of the breakup of the northern section of the Larsen B ice shelf are shown in this image pair from the Multi-angle Imaging ...

SIMULATION OF THE ICELAND VOLCANIC ERUPTION OF APRIL 2010 USING THE ENSEMBLE SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buckley, R.

2011-05-10

The Eyjafjallajokull volcanic eruption in Iceland in April 2010 disrupted transportation in Europe which ultimately affected travel plans for many on a global basis. The Volcanic Ash Advisory Centre (VAAC) is responsible for providing guidance to the aviation industry of the transport of volcanic ash clouds. There are nine such centers located globally, and the London branch (headed by the United Kingdom Meteorological Office, or UKMet) was responsible for modeling the Iceland volcano. The guidance provided by the VAAC created some controversy due to the burdensome travel restrictions and uncertainty involved in the prediction of ash transport. The Iceland volcanicmore » eruption provides a useful exercise of the European ENSEMBLE program, coordinated by the Joint Research Centre (JRC) in Ispra, Italy. ENSEMBLE, a decision support system for emergency response, uses transport model results from a variety of countries in an effort to better understand the uncertainty involved with a given accident scenario. Model results in the form of airborne concentration and surface deposition are required from each member of the ensemble in a prescribed format that may then be uploaded to a website for manipulation. The Savannah River National Laboratory (SRNL) is the lone regular United States participant throughout the 10-year existence of ENSEMBLE. For the Iceland volcano, four separate source term estimates have been provided to ENSEMBLE participants. This paper focuses only on one of those source terms. The SRNL results in relation to other modeling agency results along with useful information obtained using an ensemble of transport results will be discussed.« less

Risk perceptions and trust following the 2010 and 2011 Icelandic volcanic ash crises.

PubMed

Eiser, J Richard; Donovan, Amy; Sparks, R Stephen J

2015-02-01

Eruptions at the Icelandic volcanoes of Eyjafjallajökull (2010) and Grimsvötn (2011) produced plumes of ash posing hazards to air traffic over northern Europe. In imposing restrictions on air traffic, regulators needed to balance the dangers of accidents or aircraft damage against the cost and inconvenience to travelers and industry. Two surveys examined how members of the public viewed the necessity of the imposed restrictions and their trust in different agencies as estimators of the level of risk. Study 1 was conducted with 213 British citizens (112 males, 101 females), who completed questionnaires while waiting for flights at London City Airport during May 2012. Study 2 involved an online survey of 301 Icelandic citizens (172 males, 127 females, 2 undeclared gender) during April 2012. In both samples, there was general support for the air traffic restrictions, especially among those who gave higher estimates of the likelihood of an air accident or mishap having otherwise happened. However, in both countries, the (minority of) respondents who had personally experienced travel disruption were less convinced that these restrictions were all necessary. Scientists, the International Civil Aviation Organization, and (in Iceland) the Icelandic Department of Civil Protection were all highly trusted, and seen as erring on the side of caution in their risk estimates. Airlines were seen as more likely to underestimate any risk. We conclude that perceptions of the balance between risk and caution in judgments under uncertainty are influenced by one's own motives and those attributed to others. © 2014 Society for Risk Analysis.

The Asymmetric Continental Shelf Wave in Response to the Synoptic Wind Burst in a Semienclosed Double-Shelf Basin

NASA Astrophysics Data System (ADS)

Qu, Lixin; Lin, Xiaopei; Hetland, Robert D.; Guo, Jingsong

2018-01-01

The primary goal of this study is to investigate the asymmetric structure of continental shelf wave in a semienclosed double-shelf basin, such as the Yellow Sea. Supported by in situ observations and realistic numerical simulations, it is found that in the Yellow Sea, the shelf wave response to the synoptic wind forcing does not match the mathematically symmetric solution of classic double-shelf wave theory, but rather exhibits a westward shift. To study the formation mechanism of this asymmetric structure, an idealized model was used and two sets of experiments were conducted. The results confirm that the asymmetric structure is due to the existence of a topographic waveguide connecting both shelves. For a semienclosed basin, such as the Yellow Sea, a connection at the end of the basin eliminates the potential vorticity barrier between the two shelves and hence plays a role as a connecting waveguide for shelf waves. This waveguide enables the shelf wave to propagate from one shelf to the other shelf and produces the asymmetric response in sea level and upwind flow evolutions.

Wilkins Ice Shelf

NASA Image and Video Library

2009-04-20

The Wilkins Ice Shelf, as seen by NASA Terra spacecraft, on the western side of the Antarctic Peninsula, experienced multiple disintegration events in 2008. By the beginning of 2009, a narrow ice bridge was all that remained to connect the ice shelf to ice fragments fringing nearby Charcot Island. That bridge gave way in early April 2009. Days after the ice bridge rupture, on April 12, 2009, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite acquired this image of the southern base of the ice bridge, where it connected with the remnant ice shelf. Although the ice bridge has played a role in stabilizing the ice fragments in the region, its rupture doesn't guarantee the ice will immediately move away. http://photojournal.jpl.nasa.gov/catalog/PIA11991

The impact of economic factors on migration considerations among Icelandic specialist doctors: a cross-sectional study

PubMed Central

2013-01-01

Background Globalization has facilitated the employability of doctors almost anywhere in the world. In recent years, the migration of doctors seems to have increased. However, we lack studies on doctors’ migration from developed countries. Because the economic recession experienced by many countries might have affected the migration of doctors, research on this topic is important for the retention of doctors. Iceland was hit hard by the economic recession in 2008. Therefore, we want to explore how many specialist doctors in Iceland have considered migrating and whether economic factors at work and in private life, such as extensive cost-containment initiatives at work and worries about personal finances, are related to doctors’ migration considerations. Methods In 2010, all doctors in Iceland registered with the Icelandic Medical Association were sent an electronic cross-sectional survey by email. The 467 specialists who participated in this study represent 55% of all specialist doctors working in Iceland. Information on doctors’ contemplation of migration was available from responses to the question: “Have you considered moving and working abroad?” The predictor variables in our logistic regression model are perceived cost-containment initiatives at work, stress related to personal finances, experience of working abroad during vacations, job dissatisfaction, job position, age, and gender. Results Sixty-three per cent of Iceland’s specialist doctors had considered relocation abroad, 4% were moving in the next year or two, and 33% had not considered relocating. Logistic regression analysis shows that, controlling for age, gender, job position, job satisfaction, and experience of working abroad during vacations, doctors’ migration considerations were significantly affected by their experiences of cost-containment initiatives at work (odds ratio (OR) = 2.0, p < 0.01) and being stressed about personal finances (OR = 1.6, p < 0.001). Age

Early Holocene deglaciation of Drangajökull, Vestfirðir, Iceland

NASA Astrophysics Data System (ADS)

Harning, David J.; Geirsdóttir, Áslaug; Miller, Gifford H.; Zalzal, Kate

2016-12-01

The status of Icelandic ice caps during the early Holocene provides important constraints on North Atlantic climate and the mechanisms behind natural climate variability. A recent study postulates that Drangajökull on Vestfirðir, Iceland, persisted through the Holocene Thermal Maximum (HTM, 7.9-5.5 ka) and may be a relic from the last glacial period. We test this hypothesis with a suite of sediment cores from threshold lakes both proximal and distal to the ice cap's modern margin. Distal lakes document rapid early Holocene deglaciation from the coast and across the highlands south of the glacier. Sediment from Skorarvatn, a lake to the north of Drangajökull, shows that the northern margin of the ice cap reached a size comparable to its contemporary limit by ∼10.3 ka. Two southeastern lakes with catchments extending well beneath modern Drangajökull confirm that by ∼9.2 ka, the ice cap was reduced to ∼20% of its current area. A continuous 10.3ka record of biological productivity from Skorarvatn's sediment indicates local peak warmth occurred between 9 and 6.9 ka. The combination of warm and dry summers on Vestfirðir suggests that Drangajökull very likely melted completely shortly after 9.2 ka, similar to most other Icelandic ice caps.

Consequences of Rift Propagation for Spreading in Thick Oceanic Crust in Iceland

NASA Astrophysics Data System (ADS)

Karson, J. A.

2015-12-01

Iceland has long been considered a natural laboratory for processes related to seafloor spreading, including propagating rifts, migrating transforms and rotating microplates. The thick, hot, weak crust and subaerial processes of Iceland result in variations on the themes developed along more typical parts of the global MOR system. Compared to most other parts of the MOR, Icelandic rift zones and transform faults are wider and more complex. Rift zones are defined by overlapping arrays of volcanic/tectonic spreading segments as much as 50 km wide. The most active rift zones propagate N and S away from the Iceland hot spot causing migration of transform faults. A trail of crust deformed by bookshelf faulting forms in their wakes. Dead or dying transform strands are truncated along pseudofaults that define propagation rates close to the full spreading rate of ~20 mm/yr. Pseudofaults are blurred by spreading across wide rift zones and laterally extensive subaerial lava flows. Propagation, with decreasing spreading toward the propagator tips causes rotation of crustal blocks on both sides of the active rift zones. The blocks deform internally by the widespread reactivation of spreading-related faults and zones of weakness along dike margins. The sense of slip on these rift-parallel strike-slip faults is inconsistent with transform-fault deformation. These various deformation features as well as subaxial subsidence that accommodate the thickening of the volcanic upper crustal units are probably confined to the brittle, seismogenic, upper 10 km of the crust. At least beneath the active rift zones, the upper crust is probably decoupled from hot, mechanically weak middle and lower gabbroic crust resulting in a broad plate boundary zone between the diverging lithosphere plates. Similar processes may occur at other types of propagating spreading centers and magmatic rifts.

Ambient Noise Surface Wave Tomography of the volcanic systems of eastern Iceland

NASA Astrophysics Data System (ADS)

Green, R. G.; Priestley, K. F.; White, R. S.

2015-12-01

The Vatnajökull region of central-east Iceland lies above the head of the Iceland mantle plume where the crust is thickest due to enhanced melt supply. As a result the region contains a high density of volcanic rift systems, with six large subglacial central volcanoes. Due to the ice cover, the geological structure of the area and the location of past eruptions are poorly known. Imaging of the crustal velocity heterogeneities beneath the ice sheet aims to reveal much in terms of the structure of these volcanic plumbing systems. Mapping of significant velocity changes through time may also be indicative of movement of melt around the central volcanoes; one of which (Bárðarbunga) experienced a major rifting event in August 2014 (Sigmundsson et al. Nature 2015, Green et al. Nature Geosci. 2015). We present results from tomographic imaging of the volcanic systems in the region, using continuous data from a local broadband seismic network in central-east Iceland which provides excellent ray path coverage of the volcanic systems. This is supplemented by data from the HOTSPOT and ICEMELT experiments and the permanent monitoring stations of the Icelandic Meteorological Office. We process the continuous data following Benson et al. 2007 and automatic frequency-time analysis (FTAN) routines are used to extract more than 9000 dispersion measurements. We then generate Rayleigh wave group velocity maps which we present here. We find low velocity regions beneath the Vatnajökull icecap which are bounded by the surface expression of the volcanic rift systems. The lower velocities also extend north-west to the volcanic system under the Hofsjökull ice cap, and northwards towards Askja and the volcanic systems of the northern volcanic zone. We also produce locations and focal mechanisms of earthquakes caused by magmatic and hydrothermal activity to correlate structure with the activity of the volcanic systems.

Iceland Scotland Overflow Water flow through the Bight Fracture Zone in June-July 2015

NASA Astrophysics Data System (ADS)

Mercier, Herle; Petit, Tillys; Thierry, Virginie

2017-04-01

ISOW (Iceland Scotland Overflow Water) is the densest water in the northern Iceland Basin and a main constituent of the lower limb of the meridional overturning circulation (MOC). ISOW is the product of mixing of dense water originating from the Nordic Seas with Atlantic Water and Labrador Sea Water during its crossing of the Iceland-Faroe-Scotland Ridge and downstream acceleration. In the northern Iceland Basin, ISOW is characterized by potential density σ0 > 27.8 and salinity > 34.94. Downstream of the Iceland-Scotland Ridge, ISOW flows southwestward in a Deep Western Boundary Current along the eastern flank of the Reykjanes Ridge. Models and float trajectories previously suggested that part of the ISOW flow could cross the Reykjanes Ridge through the Bight Fracture Zone. However, no direct observations of the ISOW flow through the Bight Fracture Zone are available that would allow us to quantify its transport and water mass transformation. This lack of direct observations also prevents understanding the dynamics of the throughflow. In this study, we analyzed a set of CTDO2 and LADCP stations acquired in June-July 2015 during the Reykjanes Ridge Experiment cruise and provide new insights on the ISOW flow through the Bight Fracture Zone. The evolution of the properties as well as the velocity measurements confirm an ISOW flow from the Iceland Basin to the Irminger Sea. A main constrain to the throughflow is the presence of two sills of about 2150 m depth and two narrows. With potential densities between 27.8-27.87 kg m-3 and near bottom potential temperature of 3.02°C and salinity of 34.98, only the lightest variety of ISOW is found at the entrance of the BFZ east of the sills. In the central part of the Bight Fracture Zone, the evolution of ISOW is characterized by a decrease of 0.015 kg m-3 in the near bottom density, ascribed to the blocking of the densest ISOW variety by the sills and/or diapycnal mixing. To the West, at the exit of the BFZ, ISOW overlays

Global patterns and trends in stomach cancer incidence: Age, period and birth cohort analysis.

PubMed

Luo, Ganfeng; Zhang, Yanting; Guo, Pi; Wang, Li; Huang, Yuanwei; Li, Ke

2017-10-01

The cases of stomach cancer (SC) incidence are increasing per year and the SC burden has remained very high in some countries. We aimed to evaluate the global geographical variation in SC incidence and temporal trends from 1978 to 2007, with an emphasis on the effect of birth cohort. Joinpoint regression and age-period-cohort model were applied. From 2003 to 2007, male rate were 1.5- to 3-fold higher than female in all countries. Rates were highest in Eastern Asian and South American countries. Except for Uganda, all countries showed favorable trends. Pronounced cohort-specific increases in risk for recent birth cohorts were seen in Brazil, Colombia, Iceland, New Zealand, Norway, Uganda and US white people for males and in Australia, Brazil, Colombia, Costa Rica, Czech Republic, Ecuador, Iceland, India, Malta, New Zealand, Norway, Switzerland, United Kingdom, Uganda, US black and white people for females. The cohort-specific ratio for male significantly decreased in Japan, Malta and Spain for cohorts born since 1950 and in Austria, China, Croatia, Ecuador, Russia, Switzerland and Thailand for cohorts born since 1960 and for female in Japan for cohorts born since 1950 and in Canada, China, Croatia, Latvia, Russia and Thailand for cohorts born since 1960. Disparities in incidence and carcinogenic risk persist worldwide. The favorable trends may be due to changes in environmental exposure and lifestyle, including decreased Helicobacter pylori prevalence, increased intake of fresh fruits and vegetables, the availability of refrigeration and decreased intake of salted and preserved food and smoking prevalence. © 2017 UICC.

Satellite geological and geophysical remote sensing of Iceland

NASA Technical Reports Server (NTRS)

Williams, R. S., Jr. (Principal Investigator)

1973-01-01

The author has identified the following significant results. Under a binational, multidisciplinary experiment ERTS-1 imagery is being used to measure and map dynamic natural phenomena in Iceland. A few of the initial results from the project are: (1) a large variety of geological and volcanic features can be studied, particularly on imagery acquired at low sun angle ( 10 deg), which have not been previously recognized; (2) under optimum snow cover conditions, geothermal areas can be discerned by their snowmelt pattern or by warm spring discharge into frozen lakes; (3) a variety of map types at scale of 1:1,000,000 and 1:500,000, can be compiled, made more accurate, or updated (changes in coastline, glaciers, lakes, etc.); (4) the persistence of snow in the highland areas, during the summer months, has important ramifications to rangeland management; (5) false color composites (MSS) permitted the mapping of four types of vegetation; forested, reclaimed, cultivated areas and grasslands, and the mapping of the seasonal change of the vegetation, all of high value to rangeland management when complete, repetitive coverage of Iceland becomes a reality with an operational satellite; and (6) the volcanic eruption on Heimaey was recorded.

[Out-of-pocket health care expenditures among population groups in Iceland].

PubMed

Vilhjálmsson, Rúnar

2009-10-01

Out-of-pocket health expenditures affect access to health care. The study investigated trends in these expenditures, and whether certain population groups spent more than others. The data come from two national health surveys among Icelandic adults from 1998 and 2006. The response rate was 69% in the former survey (N=1924), and 60% in the latter (N= 1532). Average household health expenditures and household expenditure burden (expenditures as % of total household income) were compared over time and between groups. Household health expenditures increased by 29% in real terms between 1998 and 2006. The biggest items in 2006 were drugs and dental care. Women, younger and older individuals, the single and divorced, smaller households, the unemployed and non-employed, individuals with low education and income, the chronically ill, and the disabled, had the highest household expenditure burden. Comparison between 1998 and 2006 indicated increased expenditure burden among young people, students, the unemployed, and the least educated, but decreased burden among the elderly, the widowed, and parents of young children. Household health expenditures differ substantially between groups, suggesting reconsideration of current health insurance policies, especially with regard to disabled, non-employed, low-income, and young individuals.

The Icelandic economic collapse, smoking, and the role of labor-market changes.

PubMed

Ólafsdóttir, Thorhildur; Hrafnkelsson, Birgir; Ásgeirsdóttir, Tinna Laufey

2015-05-01

Smoking is related to health deterioration through increased risk of various diseases. Changes in this health behavior could contribute to the documented health improvements during economic downturns. Furthermore, the reasons for changes in behavior are not well understood. We explore smoking behavior in Iceland before and after the sudden and unexpected economic crisis in 2008. Furthermore, to explore the mechanisms through which smoking could be affected we focus on the role of labor-market changes. Both real income and working hours fell significantly and economic theory suggests that such changes can affect health behaviors which in turn affect health. We use individual longitudinal data from 2007 to 2009, incidentally before and after the crisis hit. The data originates from a postal survey, collected by The Public Health Institute in Iceland. Two outcomes are explored: smoking participation and smoking intensity, using pooled ordinary least squares (OLS) and linear probability models. The detected reduction in both outcomes is not explained by the changes in labor-market variables. Other factors in the demand function for tobacco play a more important role. The most notable are real prices which increased in particular for imported goods because of the devaluation of the Icelandic currency as a result of the economic collapse.

Health, economic crisis, and austerity: A comparison of Greece, Finland and Iceland.

PubMed

Tapia Granados, José A; Rodriguez, Javier M

2015-07-01

Reports have attributed a public health tragedy in Greece to the Great Recession and the subsequent application of austerity programs. It is also claimed that the comparison of Greece with Iceland and Finland-where austerity policies were not applied-reveals the harmful effect of austerity on health and that by protecting spending in health and social budgets, governments can offset the harmful effects of economic crises on health. We use data on life expectancy, mortality rates, incidence of infectious diseases, rates of vaccination, self-reported health and other measures to examine the evolution of population health and health services performance in Greece, Finland and Iceland since 1990-2011 or 2012-the most recent years for which data are available. We find that in the three countries most indicators of population health continued improving after the Great Recession started. In terms of population health and performance of the health care system, in the period after 2007 for which data are available, Greece did as good as Iceland and Finland. The evidence does not support the claim that there is a health crisis in Greece. On the basis of the extant evidence, claims of a public health tragedy in Greece seem overly exaggerated. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Chemical quality and regulatory compliance of drinking water in Iceland.

PubMed

Gunnarsdottir, Maria J; Gardarsson, Sigurdur M; Jonsson, Gunnar St; Bartram, Jamie

2016-11-01

Assuring sufficient quality of drinking water is of great importance for public wellbeing and prosperity. Nations have developed regulatory system with the aim of providing drinking water of sufficient quality and to minimize the risk of contamination of the water supply in the first place. In this study the chemical quality of Icelandic drinking water was evaluated by systematically analyzing results from audit monitoring where 53 parameters were assessed for 345 samples from 79 aquifers, serving 74 water supply systems. Compliance to the Icelandic Drinking Water Regulation (IDWR) was evaluated with regard to parametric values, minimum requirement of sampling, and limit of detection. Water quality compliance was divided according to health-related chemicals and indicators, and analyzed according to size. Samples from few individual locations were benchmarked against natural background levels (NBLs) in order to identify potential pollution sources. The results show that drinking compliance was 99.97% in health-related chemicals and 99.44% in indicator parameters indicating that Icelandic groundwater abstracted for drinking water supply is generally of high quality with no expected health risks. In 10 water supply systems, of the 74 tested, there was an indication of anthropogenic chemical pollution, either at the source or in the network, and in another 6 water supplies there was a need to improve the water intake to prevent surface water intrusion. Benchmarking against the NBLs proved to be useful in tracing potential pollution sources, providing a useful tool for identifying pollution at an early stage. Copyright © 2016 Elsevier GmbH. All rights reserved.

Study of crustal structure and stretch mechanism of central continental shelf of northern South China Sea

NASA Astrophysics Data System (ADS)

Cao, J.; Xia, S.; Sun, J.; Wan, K.; Xu, H.

2017-12-01

Known as a significant region to study tectonic relationship between South China block and South China Sea (SCS) block and the evolution of rifted basin in continental margin, the continental shelf of northern SCS documents the evolution from continental splitting to seafloor spreading of SCS. To investigate crustal structure of central continental shelf in northern SCS, two wide-angle onshore-offshore seismic experiments and coincident multi-channel seismic (MCS) profiles were carried out across the onshore-offshore transitional zone in northern SCS, 2010 and 2012. A total of 34 stations consisted of ocean bottom seismometers, portable and permanent land stations were deployed during the survey. The two-dimensional precise crustal structure models of central continental shelf in northern SCS was constructed from onshore to offshore, and the stretching factors along the P-wave velocity models were calculated. The models reveal that South China block is a typical continental crust with a 30-32 km Moho depth, and a localized high-velocity anomaly in middle-lower crust under land area near Hong Kong was imaged, which may reflect magma underplating caused by subduction of paleo-Pacific plate in late Mesozoic. The littoral fault zone is composed of several parallel, high-angle, normal faults that mainly trend northeast to northeast-to-east and dip to the southeast with a large displacement, and the fault is divided into several segments separated by the northwest-trending faults. The shelf zone south of LFZ was consisted of a differential thinning upper and lower continental crust, which indicate stretch thinning of passive continent margin during the Cenozoic spreading of the SCS. The results appear to further confirm that the northern margin of SCS experienced a transition from active margin to passive one during late Mesozoic and Cenozoic.

The Iceland Deep Drilling Project (IDDP): (I) A New Era in Geothermal Development?

NASA Astrophysics Data System (ADS)

Elders, W. A.; Fridleifsson, G. O.; Bird, D. K.; Reed, M. H.; Schiffman, P.; Zierenberg, R.

2007-12-01

The Iceland Deep Drilling Project (IDDP) announced in September 2007 that an international industrial consortium has signed a new contract to collaborate in exploratory deep drilling in Iceland. The main objective of the IDDP is to investigate whether it is economically feasible to produce energy from geothermal systems at supercritical conditions. This will require drilling to depths of 4 to 5 km in order to reach temperatures of 400 to 600°C. Today, geothermal wells in Iceland typically range up to 2.5 km in depth and produce steam at about 300°C, or less, at a rate sufficient to generate about 4 to 7 megawatts of electricity. It is estimated that producing steam from a well penetrating a reservoir with temperatures >450°C, and at a rate of 0.67 cubic meters a second, could generate 40 to 50 MWe. If IDDP's test of this concept proves successful, it could lead to major improvements in the development of high-temperature geothermal resources worldwide. The consortium collaborating to fund this investigation of supercritical geothermal energy consists of three leading Icelandic power companies, Hitaveita Sudurnesja Ltd., Landsvirkjun, Orkuveita Reykjavikur, together with Orkustofnun (the National Energy Authority) and Alcoa Inc. (an international aluminum company). The three power companies financed a feasibility study for the project that was completed in 2003. Each of the three power companies is committed to drill, at their own cost, a 3.5 to 4.0 km deep well in a geothermal field that they operate. The design of these wells will permit them to be deepened to 4.5 or 5.0 km by the IDDP, and funded by the consortium with additional funds from international scientific agencies. The first deep IDDP well will be drilled in the latter part of 2008 in the Krafla geothermal field near the northern end of the central rift zone of Iceland, within a volcanic caldera that has had recent volcanic activity. Two new wells, ~4 km deep, will then be drilled at the Hengill and

Seasonal Outflow of Ice Shelf Water Across the Front of the Filchner Ice Shelf, Weddell Sea, Antarctica

NASA Astrophysics Data System (ADS)

Darelius, E.; Sallée, J. B.

2018-04-01

The ice shelf water (ISW) found in the Filchner Trough, located in the southern Weddell Sea, Antarctica, is climatically important; it descends into the deep Weddell Sea contributing to bottom water formation, and it blocks warm off-shelf waters from accessing the Filchner ice shelf cavity. Yet the circulation of ISW within the Filchner Trough and the processes determining its exchange across the ice shelf front are to a large degree unknown. Here mooring records from the ice shelf front are presented, the longest of which is 4 years long. They show that the coldest (Θ =- 2.3∘C) ISW, which originates from the Ronne Trough in the west, exits the cavity across the western part of the ice shelf front during late austral summer and early autumn. The supercooled ISW escaping the cavity flows northward with a velocity of about 0.03 m/s. During the rest of the year, there is no outflow at the western site: the current is directed eastward, parallel to the ice shelf front, and the temperatures at the mooring site are slightly higher (Θ =- 2.0∘C). The eastern records show a more persistent outflow of ISW.

Spiritual well-being and quality of life among Icelanders receiving palliative care: data from Icelandic pilot-testing of a provisional measure of spiritual well-being from the European Organisation for Research and Treatment of Cancer.

PubMed

Asgeirsdottir, G H; Sigurdardottir, V; Gunnarsdottir, S; Sigurbjörnsson, E; Traustadottir, R; Kelly, E; Young, T; Vivat, B

2017-03-01

Palliative care focuses on improving quality of life (QoL). This study examined the feasibility of the Icelandic version of a provisional European Organisation for Research and Treatment of Cancer (EORTC) measure of spiritual well-being (SWB), and explored the relationship between SWB and QoL for palliative care patients in Iceland. Instruments from the EORTC were used: the provisional measure of SWB, which was undergoing pilot-testing in Iceland, and the EORTC QLQ C15-PAL. The correlation between scores was examined and descriptive statistics were used. Structured interviews explored feasibility. Thirty persons participated with average age 72 years. Belief in God or a higher power had the mean 3.33 on a 1-4 scale and the mean for overall SWB was 5.73 on a 1-7 scale. The mean score for global health/QoL was 59.4, physical functioning 48.5 and emotional functioning 78.9 on a 0-100 scale. Overall QoL was positively correlated with SWB showing r(30) = 0.386, P = 0.035. The participants found that answering the provisional EORTC QLQ-SWB prompted an emotional response and took the opportunity to discuss the subject. The provisional SWB measure was found relevant for the Icelandic context, and the study indicates that SWB and QoL are closely connected. © 2015 John Wiley & Sons Ltd.

41 CFR 101-27.205 - Shelf-life codes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Shelf-life codes. 101-27...-Management of Shelf-Life Materials § 101-27.205 Shelf-life codes. Shelf-life items shall be identified by use of a one-digit code to provide for uniform coding of shelf-life materials by all agencies. (a) The...

41 CFR 101-27.205 - Shelf-life codes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Shelf-life codes. 101-27...-Management of Shelf-Life Materials § 101-27.205 Shelf-life codes. Shelf-life items shall be identified by use of a one-digit code to provide for uniform coding of shelf-life materials by all agencies. (a) The...

41 CFR 101-27.205 - Shelf-life codes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Shelf-life codes. 101-27...-Management of Shelf-Life Materials § 101-27.205 Shelf-life codes. Shelf-life items shall be identified by use of a one-digit code to provide for uniform coding of shelf-life materials by all agencies. (a) The...

41 CFR 101-27.205 - Shelf-life codes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 2 2013-07-01 2012-07-01 true Shelf-life codes. 101-27...-Management of Shelf-Life Materials § 101-27.205 Shelf-life codes. Shelf-life items shall be identified by use of a one-digit code to provide for uniform coding of shelf-life materials by all agencies. (a) The...

41 CFR 101-27.205 - Shelf-life codes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 41 Public Contracts and Property Management 2 2012-07-01 2012-07-01 false Shelf-life codes. 101-27...-Management of Shelf-Life Materials § 101-27.205 Shelf-life codes. Shelf-life items shall be identified by use of a one-digit code to provide for uniform coding of shelf-life materials by all agencies. (a) The...

Understanding Ice Shelf Basal Melting Using Convergent ICEPOD Data Sets: ROSETTA-Ice Study of Ross Ice Shelf

NASA Astrophysics Data System (ADS)

Bell, R. E.; Frearson, N.; Tinto, K. J.; Das, I.; Fricker, H. A.; Siddoway, C. S.; Padman, L.

2017-12-01

The future stability of the ice shelves surrounding Antarctica will be susceptible to increases in both surface and basal melt as the atmosphere and ocean warm. The ROSETTA-Ice program is targeted at using the ICEPOD airborne technology to produce new constraints on Ross Ice Shelf, the underlying ocean, bathymetry, and geologic setting, using radar sounding, gravimetry and laser altimetry. This convergent approach to studying the ice-shelf and basal processes enables us to develop an understanding of the fundamental controls on ice-shelf evolution. This work leverages the stratigraphy of the ice shelf, which is detected as individual reflectors by the shallow-ice radar and is often associated with surface scour, form close to the grounding line or pinning points on the ice shelf. Surface accumulation on the ice shelf buries these reflectors as the ice flows towards the calving front. This distinctive stratigraphy can be traced across the ice shelf for the major East Antarctic outlet glaciers and West Antarctic ice streams. Changes in the ice thickness below these reflectors are a result of strain and basal melting and freezing. Correcting the estimated thickness changes for strain using RIGGS strain measurements, we can develop decadal-resolution flowline distributions of basal melt. Close to East Antarctica elevated melt-rates (>1 m/yr) are found 60-100 km from the calving front. On the West Antarctic side high melt rates primarily develop within 10 km of the calving front. The East Antarctic side of Ross Ice Shelf is dominated by melt driven by saline water masses that develop in Ross Sea polynyas, while the melting on the West Antarctic side next to Hayes Bank is associated with modified Continental Deep Water transported along the continental shelf. The two sides of Ross Ice Shelf experience differing basal melt in part due to the duality in the underlying geologic structure: the East Antarctic side consists of relatively dense crust, with low amplitude

Putting Temperature and Oxygen Thresholds of Marine Animals in Context of Environmental Change: A Regional Perspective for the Scotian Shelf and Gulf of St. Lawrence

PubMed Central

2016-01-01

We conducted a literature review of reported temperature, salinity, pH, depth and oxygen preferences and thresholds of important marine species found in the Gulf of St. Lawrence and Scotian Shelf region. We classified 54 identified fishes and macroinvertebrates as important either because they support a commercial fishery, have threatened or at risk status, or meet one of the following criteria: bycatch, baitfish, invasive, vagrant, important for ecosystem energy transfer, or predators or prey of the above species. The compiled data allow an assessment of species-level impacts including physiological stress and mortality given predictions of future ocean physical and biogeochemical conditions. If an observed, multi-decadal oxygen trend on the central Scotian Shelf continues, a number of species will lose favorable oxygen conditions, experience oxygen-stress, or disappear due to insufficient oxygen in the coming half-century. Projected regional trends and natural variability are both large, and natural variability will act to alternately amplify and dampen anthropogenic changes. When estimates of variability are included with the trend, species encounter unfavourable oxygen conditions decades sooner. Finally, temperature and oxygen thresholds of adult Atlantic wolffish (Anarhichas lupus) and adult Atlantic cod (Gadus morhua) are assessed in the context of a potential future scenario derived from high-resolution ocean models for the central Scotian Shelf. PMID:27997536

Putting Temperature and Oxygen Thresholds of Marine Animals in Context of Environmental Change: A Regional Perspective for the Scotian Shelf and Gulf of St. Lawrence.

PubMed

Brennan, Catherine E; Blanchard, Hannah; Fennel, Katja

2016-01-01

We conducted a literature review of reported temperature, salinity, pH, depth and oxygen preferences and thresholds of important marine species found in the Gulf of St. Lawrence and Scotian Shelf region. We classified 54 identified fishes and macroinvertebrates as important either because they support a commercial fishery, have threatened or at risk status, or meet one of the following criteria: bycatch, baitfish, invasive, vagrant, important for ecosystem energy transfer, or predators or prey of the above species. The compiled data allow an assessment of species-level impacts including physiological stress and mortality given predictions of future ocean physical and biogeochemical conditions. If an observed, multi-decadal oxygen trend on the central Scotian Shelf continues, a number of species will lose favorable oxygen conditions, experience oxygen-stress, or disappear due to insufficient oxygen in the coming half-century. Projected regional trends and natural variability are both large, and natural variability will act to alternately amplify and dampen anthropogenic changes. When estimates of variability are included with the trend, species encounter unfavourable oxygen conditions decades sooner. Finally, temperature and oxygen thresholds of adult Atlantic wolffish (Anarhichas lupus) and adult Atlantic cod (Gadus morhua) are assessed in the context of a potential future scenario derived from high-resolution ocean models for the central Scotian Shelf.

Linkages between Icelandic Low position and SE Greenland winter precipitation

NASA Astrophysics Data System (ADS)

Berdahl, M.; Rennermalm, A. K.; Hammann, A. C.; Mioduszewski, J.; Hameed, S.; Tedesco, M.; Stroeve, J. C.; Mote, T. L.

2015-12-01

Greenland's largest flux of precipitation occurs in its Southeast (SE) region. An understanding of the mechanisms controlling precipitation in this region is lacking despite its disproportionate importance in the mass balance of Greenland and the consequent contributions to sea level rise. We use weather station data from the Danish Meteorological Institute to reveal the governing influences on precipitation in SE Greenland during the winter and fall. We find that precipitation in the fall is significantly correlated to the longitude of the Icelandic Low and the NAO. Winter precipitation is correlated with the strength and longitude of the Icelandic Low, as well as the NAO. We show that in years of extreme high precipitation, onshore winds dominate, thereby advecting more moisture inland. In low precipitation years, winds are more westerly, approaching the stations from land. Understanding the controls of SE Greenland precipitation will help us predict how future precipitation in this key region may change in a warming climate.

The FUTUREVOLC Supersite's e-Infrastructure - A multidisciplinary data hub and data service for Icelandic Volcanoes

NASA Astrophysics Data System (ADS)

Vogfjörd, Kristín S.; Sigmundsson, Freysteinn; Sverrisson, Sverrir Th.; Sigurdsson, Sigurdur F.; Ófeigsson, Benedikt G.; Arnarsson, Ólafur S.; Kristinsson, Ingvar; Ilyinskaya, Evgenia; Oddsdóttir, Thorarna Ýr; Bergsveinsson, Sölvi Th.; Hjartansson, Kristján R.

2014-05-01

The FUTUREVOLC volanological supersite will establish a data hub and dataservice, where researchers, hazard managers and other stake holders can freely obtain access to multidisciplinary data and products on activity, unrest and eruptions at Icelandic volcanoes. The supersite is firmly founded on close interaction between the main Icelandic volcanological research and monitoring institutions, in coordination with expertise from European researchers participating in FUTUREVOLC. The hub is located at the Icelandic Meteorological Office (IMO), an institution responsible for monitoring and archiving data on all natural hazards in Iceland and, which also has a mandate as the state volcano observatory. This association will ensure a long-term sustainable data service. The data accessible at the hub include in-situ and space-based observations, products and models from all the relevant disciplines contributing to volcanological research and local as well as cross-border hazard management, i.e. Earth sciences, atmospheric science, hydrology, remote sensing and space science. Access to the data will be in compliance with the access policy of the GEO (Group on Earth Observations), providing registered users with easy and timely access to data and products of documented quality. This commitment has already led to the acceptance of FUTUREVOLC as a permanent geohazard supersite by CEOS (Committee on Earth Observation Satellites), which will ensure access to additional satellite data and products on Icelandic volcanoes. To facilitate services to seismological data at the supersite hub, the IMO is reconstructing its existing data base and utilizing the SeisComp3 software to manage waveform and parameter data. The accompanying ArcLink component will be used to provide access to event data and waveforms. Access to GPS data will be provided by the GSAC web service which has been installed at the IMO through collaboration with UNAVCO. If appropriate, the format and data base

Progress of Icelandic Lava Flows Charted by NASA EO-1 Spacecraft

NASA Image and Video Library

2014-09-09

On the night of Sept. 6, 2014 NASA Earth Observing 1 EO-1 spacecraft observed the ongoing eruption at Holuhraun, Iceland. Partially covered by clouds, this scene shows the extent of the lava flows that have been erupting.

Ice-Shelf Melt Response to Changing Winds and Glacier Dynamics in the Amundsen Sea Sector, Antarctica

NASA Astrophysics Data System (ADS)

Donat-Magnin, Marion; Jourdain, Nicolas C.; Spence, Paul; Le Sommer, Julien; Gallée, Hubert; Durand, Gaël.

2017-12-01

It has been suggested that the coastal Southern Ocean subsurface may warm over the 21st century in response to strengthening and poleward shifting winds, with potential adverse effects on West Antarctic glaciers. However, using a 1/12° ocean regional model that includes ice-shelf cavities, we find a more complex response to changing winds in the Amundsen Sea. Simulated offshore subsurface waters get colder under strengthened and poleward shifted winds representative of the SAM projected trend. The buoyancy-driven circulation induced by ice-shelf melt transports this cold offshore anomaly onto the continental shelf, leading to cooling and decreased melt below 450 m. In the vicinity of ice-shelf fronts, Ekman pumping contributes to raise the isotherms in response to changing winds. This effect overwhelms the horizontal transport of colder offshore waters at intermediate depths (between 200 and 450 m), and therefore increases melt rates in the upper part of the ice-shelf cavities, which reinforces the buoyancy-driven circulation and further contributes to raise the isotherms. Then, prescribing an extreme grounding line retreat projected for 2100, the total melt rates simulated underneath Thwaites and Pine Island are multiplied by 2.5. Such increase is explained by a larger ocean/ice interface exposed to CDW, which is then amplified by a stronger melt-induced circulation along the ice draft. Our main conclusions are that (1) outputs from ocean models that do not represent ice shelf cavities (e.g., CMIP5 models) should not be directly used to predict the thermal forcing of future ice shelf cavities; (2) coupled ocean/ice sheet models with a velocity-dependent melt formulation are needed for future projections of glaciers experiencing a significant grounding line retreat.

New Proposed Drilling at Surtsey Volcano, Iceland

NASA Astrophysics Data System (ADS)

Jackson, Marie D.

2014-12-01

Surtsey, an isolated oceanic island and a World Heritage Site of the United Nations Educational, Scientific and Cultural Organization, is a uniquely well-documented natural laboratory for investigating processes of rift zone volcanism, hydrothermal alteration of basaltic tephra, and biological colonization and succession in surface and subsurface pyroclastic deposits. Deposits from Surtsey's eruptions from 1963 to 1967 were first explored via a 181-meter hole drilled in 1979 by the U.S. Geological Survey and Icelandic Museum of Natural History.

The source and longevity of sulfur in an Icelandic flood basalt eruption plume

NASA Astrophysics Data System (ADS)

Ilyinskaya, Evgenia; Edmonds, Marie; Mather, Tamsin; Schmidt, Anja; Hartley, Margaret; Oppenheimer, Clive; Pope, Francis; Donovan, Amy; Sigmarsson, Olgeir; Maclennan, John; Shorttle, Oliver; Francis, Peter; Bergsson, Baldur; Barsotti, Sara; Thordarson, Thorvaldur; Bali, Eniko; Keller, Nicole; Stefansson, Andri

2015-04-01

The Holuhraun fissure eruption (Bárðarbunga volcanic system, central Iceland) has been ongoing since 31 August 2014 and is now the largest in Europe since the 1783-84 Laki event. For the first time in the modern age we have the opportunity to study at first hand the environmental impact of a flood basalt fissure eruption (>1 km3 lava). Flood basalt eruptions are one of the most hazardous volcanic scenarios in Iceland and have had enormous societal and economic consequences across the northern hemisphere in the past. The Laki eruption caused the deaths of >20% of the Icelandic population by environmental pollution and famine and potentially also increased European levels of mortality through air pollution by sulphur-bearing gas and aerosol. A flood basalt eruption was included in the UK National Risk Register in 2012 as one of the highest priority risks. The gas emissions from Holuhraun have been sustained since its beginning, repeatedly causing severe air pollution in populated areas in Iceland. During 18-22 September, SO2 fluxes reached 45 kt/day, a rate of outgassing rarely observed during sustained eruptions, suggesting that the sulfur loading per kg of erupted magma exceeds both that of other recent eruptions in Iceland and perhaps also other historic basaltic eruptions globally. This raises key questions regarding the origin of these prodigious quantities of sulphur. A lack of understanding of the source of this sulfur, the conversion rates of SO2 gas into aerosol, the residence times of aerosol in the plume and the dependence of these on meteorological factors is limiting our confidence in the ability of atmospheric models to forecast gas and aerosol concentrations in the near- and far-field from Icelandic flood basalt eruptions. In 2015 our group is undertaking a project funded by UK NERC urgency scheme to investigate several aspects of the sulfur budget at Holuhraun using a novel and powerful approach involving simultaneous tracking of sulfur and

Glider monitoring of shelf suspended particle dynamics and transport during storm and flooding conditions

NASA Astrophysics Data System (ADS)

Bourrin, François; Many, Gaël; Durrieu de Madron, Xavier; Martín, Jacobo; Puig, Pere; Houpert, Loic; Testor, Pierre; Kunesch, Stéphane; Mahiouz, Karim; Béguery, Laurent

2015-10-01

different wavelengths suggests that the coastal area and the bottom nepheloid layer during the largest storm are primarily composed of coarse particles, probably macroflocs, and that the size of particles decreases further offshore. A similar trend, albeit less contrasted, is observed after the flooding. This work provided a unique synoptic view across the entire shelf of the impact of a typical Mediterranean storm on bottom sediment erosion and particulate fluxes. Repeated glider transects across the south-western part of the Gulf of Lions shelf permitted for the first time to measure continuously the thermo-haline structures, the suspended particles concentrations and size, the current speed, and to estimate the particulate transport before, during and after typical Mediterranean storm events. Glider data complement and compare well with concomitant high frequency time series at fixed stations along the coast and in a downstream submarine canyon.

Bottom Water Acidification and Warming on the Western Eurasian Arctic Shelves: Dynamical Downscaling Projections

NASA Astrophysics Data System (ADS)

Wallhead, P. J.; Bellerby, R. G. J.; Silyakova, A.; Slagstad, D.; Polukhin, A. A.

2017-10-01

The impacts of oceanic CO2 uptake and global warming on the surface ocean environment have received substantial attention, but few studies have focused on shelf bottom water, despite its importance as habitat for benthic organisms and demersal fisheries such as cod. We used a downscaling ocean biogeochemical model to project bottom water acidification and warming on the western Eurasian Arctic shelves. A model hindcast produced 14-18 year acidification trends that were largely consistent with observational estimates at stations in the Iceland and Irminger Seas. Projections under SRES A1B scenario revealed a rapid and spatially variable decline in bottom pH by 0.10-0.20 units over 50 years (2.5%-97.5% quantiles) at depths 50-500 m on the Norwegian, Barents, Kara, and East Greenland shelves. Bottom water undersaturation with respect to aragonite occurred over the entire Kara shelf by 2040 and over most of the Barents and East Greenland shelves by 2070. Shelf acidification was predominantly driven by the accumulation of anthropogenic CO2, and was concurrent with warming of 0.1-2.7°C over 50 years. These combined perturbations will act as significant multistressors on the Barents and Kara shelves. Future studies should aim to improve the resolution of shelf bottom processes in models, and should consider the Kara Sea and Russian shelves as possible bellwethers of shelf acidification.

Seismic evidence for a tilted mantle plume and north-south mantle flow beneath Iceland

USGS Publications Warehouse

Shen, Y.; Solomon, S.C.; Bjarnason, I. Th; Nolet, G.; Morgan, W.J.; Allen, R.M.; Vogfjord, K.; Jakobsdottir, S.; Stefansson, R.; Julian, B.R.; Foulger, G.R.

2002-01-01

Shear waves converted from compressional waves at mantle discontinuities near 410- and 660-km depth recorded by two broadband seismic experiments in Iceland reveal that the center of an area of anomalously thin mantle transition zone lies at least 100 km south of the upper-mantle low-velocity anomaly imaged tomographically beneath the hotspot. This offset is evidence for a tilted plume conduit in the upper mantle, the result of either northward flow of the Icelandic asthenosphere or southward flow of the upper part of the lower mantle in a no-net-rotation reference frame. ?? 2002 Elsevier Science B.V. All rights reserved.

Shelf Life Prediction for Canned Gudeg using Accelerated Shelf Life Testing (ASLT) Based on Arrhenius Method

NASA Astrophysics Data System (ADS)

Nurhayati, R.; Rahayu NH, E.; Susanto, A.; Khasanah, Y.

2017-04-01

Gudeg is traditional food from Yogyakarta. It is consist of jackfruit, chicken, egg and coconut milk. Gudeg generally have a short shelf life. Canning or commercial sterilization is one way to extend the shelf life of gudeg. This aims of this research is to predict the shelf life of Andrawinaloka canned gudeg with Accelerated Shelf Life Test methods, Arrhenius model. Canned gudeg stored at three different temperature, there are 37, 50 and 60°C for two months. Measuring the number of Thio Barbituric Acid (TBA), as a critical aspect, were tested every 7 days. Arrhenius model approach is done with the equation order 0 and order 1. The analysis showed that the equation of order 0 can be used as an approach to estimating the shelf life of canned gudeg. The storage of Andrawinaloka canned gudeg at 30°C is predicted untill 21 months and 24 months for 25°C.

Type D personality is associated with impaired psychological status and unhealthy lifestyle in Icelandic cardiac patients: a cross-sectional study.

PubMed

Svansdottir, Erla; van den Broek, Krista C; Karlsson, Hrobjartur D; Gudnason, Thorarinn; Denollet, Johan

2012-01-18

Type D (distressed) personality has been associated with adverse cardiac prognosis and poor emotional well-being in cardiac patients, but it is still unclear what mechanisms link Type D personality with poor clinical outcomes in cardiac patients. In the present cohort of Icelandic cardiac patients, we examined potential pathways that may explain this relationship. The objectives were to examine 1) the association between Type D personality and impaired psychological status, and to explore whether this association is independent of disease severity; and 2) the association between Type D personality and an unhealthy lifestyle. A sample of 268 Icelandic coronary angiography patients (74% males (N = 199); mean age 62.9 years (SD 10.5), range 28-85 years) completed the Type D Scale (DS14), Hospital Anxiety and Depression Scale (HADS), and Perceived Stress Scale (PSS) at hospitalization. Health-related behaviors were assessed 4 months following angiography. Clinical data were collected from medical files. Type D personality was associated with an increased risk of anxiety (OR 2.97, 95% CI:1.55-5.69), depression (OR 4.01, 95% CI:1.42-11.29), and stress (OR 5.99, 95% CI:3.08-11.63), independent of demographic variables and disease severity. Furthermore, fish consumption was lower among Type Ds, as 21% of Type Ds versus 5% of non-Type Ds consumed fish < 1 a week (p < 0.001). Type D patients were also more likely to smoke at follow-up (22% versus 10%, p = 0.024) and to use antidepressants (17% versus 9%, p = 0.049) and sleeping pills (49% versus 33%, p = 0.019) compared to non-Type Ds. Type D personality was not associated with other health-related behaviors, aside from trends towards less fruit and vegetable consumption, and more weight gain. Type D personality was associated with psychological distress and an unhealthy lifestyle in Icelandic cardiac patients. Future studies should further investigate the association between Type D personality and health-related behaviors.

Annual cycle and spatial trends in fatty acid composition of suspended particulate organic matter across the Beaufort Sea shelf

NASA Astrophysics Data System (ADS)

Connelly, Tara L.; Businski, Tara N.; Deibel, Don; Parrish, Christopher C.; Trela, Piotr

2016-11-01

Fatty acid profiles of suspended particulate organic matter (POM) were determined over an annual cycle (September 2003 to August 2004) on the Beaufort Sea shelf, Canadian Arctic. Special emphasis was placed on the nutritional quality of the fatty acid pool available to zooplankton by examining spatial and temporal patterns in the proportions of total polyunsaturated fatty acids (PUFA) and the essential fatty acids 22:6n-3 (DHA) and 20:5n-3 (EPA). EPA and DHA were the two most abundant PUFA throughout the study period. A log-ratio multivariate (LRA) analysis revealed strong structure in fatty acid profiles related to season and depth. Dominant fatty acids accounting for the observed trend included 18:5n-3, 18:4n-3, 16:1n-7, 20:5n-3, 18:0 and 20:3n-3. We observed a shift in fatty acid profiles from summer to autumn (e.g., from 16:1n-7 and EPA to 18:5n-3 and 18:4n-3) that likely corresponded to a shift in the relative importance of diatoms versus dinoflagellates, prymnesiophytes and/or prasinophytes to the POM pool. Fatty acid composition during winter was dominated by more refractory saturated fatty acids. A surprising finding was the depth and seasonal trend of 20:3n-3, which was higher in winter, aligned with 18:0 in the LRA, but behaved differently than other n-3 PUFA. We interpret fatty acid profiles during summer to be predominantly driven by phytoplankton inputs, whereas fatty acid profiles in winter were dominated by fatty acids that were left over after consumption and/or were generated by heterotrophs. The highest diatom inputs (EPA, the diatom fatty acid marker), n-3/n-6 ratios, and C16 PUFA index were located in an upwelling region off Cape Bathurst. This study is the first annual time series of fatty acid profiles of POM in Arctic seas, expanding our knowledge of the composition of POM throughout the dark season.

Developing a national framework for safe drinking water--case study from Iceland.

PubMed

Gunnarsdottir, Maria J; Gardarsson, Sigurdur M; Bartram, Jamie

2015-03-01

Safe drinking water is one of the fundaments of society and experience has shown that a holistic national framework is needed for its effective provision. A national framework should include legal requirements on water protection, surveillance on drinking water quality and performance of the water supply system, and systematic preventive management. Iceland has implemented these requirements into legislation. This case study analyzes the success and challenges encountered in implementing the legislation and provide recommendations on the main shortcomings identified through the Icelandic experience. The results of the analysis show that the national framework for safe drinking water is mostly in place in Iceland. The shortcomings include the need for both improved guidance and control by the central government; and for improved surveillance of the water supply system and implementation of the water safety plan by the Local Competent Authorities. Communication to the public and between stakeholders is also insufficient. There is also a deficiency in the national framework regarding small water supply systems that needs to be addressed. Other elements are largely in place or on track. Most of the lessons learned are transferable to other European countries where the legal system around water safety is built on a common foundation from EU directives. The lessons can also provide valuable insights into how to develop a national framework elsewhere. Copyright © 2014 Elsevier GmbH. All rights reserved.

Silicate versus carbonate weathering in Iceland: New insights from Ca isotopes

NASA Astrophysics Data System (ADS)

Jacobson, Andrew D.; Grace Andrews, M.; Lehn, Gregory O.; Holmden, Chris

2015-04-01

Several studies have measured riverine fluxes of Ca and carbonate alkalinity in Iceland with the aim of quantifying the role of basalt weathering in the long-term carbon cycle. A major assumption is that all of the Ca and alkalinity originates from the dissolution of Ca-bearing silicate minerals, such as plagioclase and clinopyroxene. However, hydrothermal calcite occurs throughout Iceland, and even trace levels are expected to impact river geochemistry owing to the mineral's high solubility and fast dissolution rate. To test this hypothesis, we used a new, high-precision Ca isotope MC-TIMS method (δ44/40Ca; 2σSD = ± 0.04 ‰) to trace sources of Ca in Icelandic rivers. We report elemental and Ca isotope data for rivers, high- and low-temperature groundwater, basalt, hydrothermal calcite (including Iceland Spar), and stilbite and heulandite, which are two types of zeolites commonly formed during low-grade metamorphism of basalt. In agreement with previous research, we find that rivers have higher δ44/40Ca values than basalt, with a maximum difference of ∼0.40‰. This difference may reflect isotope fractionation in the weathering zone, i.e., preferential uptake of 40Ca during clay mineral formation, adsorption, and other geochemical processes that cycle Ca. However, calcite δ44/40Ca values are also up to ∼0.40‰ higher than bedrock values, and on a diagram of δ44/40Ca versus Sr/Ca, nearly all waters plot within a plausible mixing domain bounded by the measured compositions of basalt and calcite, with glacial rivers plotting closer to calcite than non-glacial rivers. Calcite and heulandite form during hydrothermal alteration of basalt in the deep lava pile and often occur together in metabasalts now exposed at the surface. Because heulandite δ44/40Ca values are ∼1-2‰ lower than basalt, we suggest that 40Ca uptake by heudlandite explains the relatively high δ44/40Ca values of calcite and that calcite weathering in turn elevates riverine δ44/40Ca

An Icelandic Version of McMasters Family Assessment Device (FAD)

ERIC Educational Resources Information Center

Juliusdottir, Gudlaug M.; Olafsdottir, Hrefna

2015-01-01

Purpose: An analysis of the psychometric properties of an Icelandic version of McMasters Family Assessment Device (FAD) was conducted in this study. Method: Two groups, clinical and nonclinical, comprising of 529 parents answered the FAD. The study examined the internal reliability and discriminant validity of the instrument in addition to…

Biomarker-based reconstruction of late Holocene sea-ice variability: East versus West Greenland continental shelf.

NASA Astrophysics Data System (ADS)

Kolling, H. M.; Stein, R. H.; Fahl, K.

2016-12-01

Sea is a critical component of the climate system and its role is not yet fully understood e.g. the recent rapid decrease in sea ice is not clearly reflected in climate models. This illustrates the need for high-resolution proxy-based sea-ice reconstructions going beyond the time scale of direct measurements in order to understand the processes controlling present and past natural variability of sea ice on short time scales. Here we present the first comparison of two high-resolution biomarker records from the East and West Greenland Shelf for the late Holocene. Both areas are highly sensitive to sea-ice changes as they are influenced by the East Greenland Current, the main exporter of Arctic freshwater and sea ice. On the East Greenland Shelf, we do not find any clear evidence for a long-term increase of sea ice during the late Holocene Neoglacial. This sea-ice record seems to be more sensitive to short-term climate events, such as the Roman Warm Period, the Dark Ages, the Medieval Warm Period and the Little Ice Age. In contrary, the West Greenland Shelf record shows a strong and gradual increase in sea ice concentration and a reduction in marine productivity markers starting near 1.6 ka. In general, the increase in sea ice seems to follow the decreasing solar insolation trend. Short-term events are not as clearly pronounced as on the East Greenland Shelf. A comparison to recently published foraminiferal records from the same cores (Perner et al., 2011, 2015) illuminates the differences of biomarker and micropaleontoligical proxies. It seems that the general trend is reflected in both proxies but the signal of small-scale events is preserved rather differently, pointing towards different environmental requirements of the species behind both proxies. References: Perner, K., et al., 2011. Quat. Sci. Revs. 30, 2815-2826 Perner, K., et al., 2015. Quat. Sci. Revs. 129, 296-307

The 20th-century development and expansion of Louisiana shelf hypoxia, Gulf of Mexico

USGS Publications Warehouse

Osterman, L.E.; Poore, R.Z.; Swarzenski, P.W.; Senn, D.B.; DiMarco, Steven F.

2009-01-01

Since systematic measurements of Louisiana continental-shelf waters were initiated in 1985, hypoxia (oxygen content <2 mg L-1) has increased considerably in an area termed the dead zone. Monitoring and modeling studies have concluded that the expansion of the Louisiana shelf dead zone is related to increased anthropogenically derived nutrient delivery from the Mississippi River drainage basin, physical and hydrographical changes of the Louisiana Shelf, and possibly coastal erosion of wetlands in southern Louisiana. In order to track the development and expansion of seasonal low-oxygen conditions on the Louisiana shelf prior to 1985, we used a specific low-oxygen foraminiferal faunal proxy, the PEB index, which has been shown statistically to represent the modern Louisiana hypoxia zone. We constructed a network of 13 PEB records with excess 210Pb-derived chronologies to establish the development of low-oxygen and hypoxic conditions over a large portion of the modern dead zone for the last 100 years. The PEB index record indicates that areas of low-oxygen bottom water began to appear in the early 1910s in isolated hotspots near the Mississippi Delta and rapidly expanded across the entire Louisiana shelf beginning in the 1950s. Since ???1950, the percentage of PEB species has steadily increased over a large portion of the modern dead zone. By 1960, subsurface low-oxygen conditions were occurring seasonally over a large part of the geographic area now known as the dead zone. The long-term trends in the PEB index are consistent with the 20th-century observational and proxy data for low oxygen and hypoxia. ?? 2009 US Government.

Shelf life prediction of canned fried-rice using accelerated shelf life testing (ASLT) arrhenius method

NASA Astrophysics Data System (ADS)

Kurniadi, M.; Bintang, R.; Kusumaningrum, A.; Nursiwi, A.; Nurhikmat, A.; Susanto, A.; Angwar, M.; Triwiyono; Frediansyah, A.

2017-12-01

Research on shelf-life prediction of canned fried rice using Accelerated Shelf-life Test (ASLT) of Arrhenius model has been conducted. The aim of this research to predict shelf life of canned-fried rice products. Lethality value of 121°C for 15 and 20 minutes and Total Plate count methods are used to determine time and temperatures of sterilization process.Various storage temperatures of ASLT Arrhenius method were 35, 45 and 55°C during 35days. Rancidity is one of the derivation quality of canned fried rice. In this research, sample of canned fried rice is tested using rancidity value (TBA). TBA value was used as parameter which be measured once a week periodically. The use of can for fried rice without any chemical preservative is one of the advantage of the product, additionaly the use of physicalproperties such as temperature and pressure during its process can extend the shelf life and reduce the microbial contamination. The same research has never done before for fried rice as ready to eat meal. The result showed that the optimum conditions of sterilization process were 121°C,15 minutes with total plate count number of 9,3 × 101 CFU/ml. Lethality value of canned fried rice at 121°C,15 minutes was 3.63 minutes. The calculated Shelf-life of canned fried rice using Accelerated Shelf-life Test (ASLT) of Arrhenius method was 10.3 months.

Ash from Eyjafjallajökull Volcano, Iceland Stretches over the North Atlantic

NASA Image and Video Library

2010-04-18

This image from NASA Terra spacecraft shows ash plumes from Eyjafjallajökull Volcano, Iceland stretching over the North Atlantic; the volcano erupted on April 14, 2010 bringing closure to major airports in Europe.

Sediment-starved sand ridges on a mixed carbonate/siliciclastic inner shelf off west-central Florida

USGS Publications Warehouse

Harrison, S.E.; Locker, S.D.; Hine, A.C.; Edwards, J.H.; Naar, D.F.; Twichell, D.C.; Mallinson, D.J.

2003-01-01

High-resolution side-scan mosaics, sediment analyses, and physical process data have revealed that the mixed carbonate/siliciclastic, inner shelf of west-central Florida supports a highly complex field of active sand ridges mantled by a hierarchy of bedforms. The sand ridges, mostly oriented obliquely to the shoreline trend, extend from 2 km to over 25 km offshore. They show many similarities to their well-known counterparts situated along the US Atlantic margin in that both increase in relief with increasing water depth, both are oriented obliquely to the coast, and both respond to modern shelf dynamics. There are significant differences in that the sand ridges on the west-central Florida shelf are smaller in all dimensions, have a relatively high carbonate content, and are separated by exposed rock surfaces. They are also shoreface-detached and are sediment-starved, thus stunting their development. Morphological details are highly distinctive and apparent in side-scan imagery due to the high acoustic contrast. The seafloor is active and not a relict system as indicated by: (1) relatively young AMS 14C dates (< 1600 yr BP) from forams in the shallow subsurface (1.6 meters below seafloor), (2) apparent shifts in sharply distinctive grayscale boundaries seen in time-series side-scan mosaics, (3) maintenance of these sharp acoustic boundaries and development of small bedforms in an area of constant and extensive bioturbation, (4) sediment textural asymmetry indicative of selective transport across bedform topography, (5) morphological asymmetry of sand ridges and 2D dunes, and (6) current-meter data indicating that the critical threshold velocity for sediment transport is frequently exceeded. Although larger sand ridges are found along other portions of the west-central Florida inner shelf, these smaller sand ridges are best developed seaward of a major coastal headland, suggesting some genetic relationship. The headland may focus and accelerate the N-S reversing

[Transport and treatment of patients with STEMI in rural Iceland--Only a few patients receive PPCI within 120 minutes].

PubMed

Sigmundsson, Thórir S; Arnarson, Daníel; Rafnsson, Arnar; Magnússon, Viðar; Gunnarsson, Gunnar Thór; Thorgeirsson, Gestur

2016-01-01

ST-segment Elevation Myocardial Infarction (STEMI) is a life-threatening disease and good outcome depends on early restoration of coronary blood flow. Primary percutaneous coronary intervention (PPCI) is the treatment of choice if performed within 120 minutes of first medical contact (FMC) but in case of anticipated long transport or delays, pre-hospital fibrinolysis is indicated. The aim was to study transport times and adherence to clinical guidelines in patients with STEMI transported from outside of the Reykjavik area to Landspitali University Hospital in Iceland. Retrospective chart review was conducted of all patients diagnosed with STEMI outside of the Reykjavik area and transported to Landspitali University Hospital in Reykjavik in 2011-2012. Descriptive statistical analysis and hypothesis testing was applied. Eighty-six patients had signs of STEMI on electrocardiogram (ECG) at FMC. In southern Iceland nine patients (21%) underwent PPCI within 120 minutes (median 157 minutes) and no patient received fibrinolysis. In northern Iceland and The Vestman Islands, where long transport times are expected, 96% of patients eligible for fibrinolysis (n=31) received appropriate therapy in a median time of 57 minutes. Significantly fewer patients received appropriate anticoagulation treatment with clopidogrel and enoxaparin in southern Iceland compared to the northern part. Mortality rate was 7% and median length of stay in hospital was 6 days. Time from FMC to PPCI is longer than 120 minutes in the majority of cases. Pre-hospital fibrinolysis should be considered as first line treatment in all parts of Iceland outside of the Reykjavik area. Directly electronically transmitted ECGs and contact with cardiologist could hasten diagnosis and decrease risk of unnecessary interhospital transfer. A STEMI database should be established in Iceland to facilitate quality control.

Mechanism for the recent ocean warming events on the Scotian Shelf of eastern Canada

NASA Astrophysics Data System (ADS)

Brickman, D.; Hebert, D.; Wang, Z.

2018-03-01

In 2012, 2014, and 2015 anomalous warm events were observed in the subsurface waters in the Scotian Shelf region of eastern Canada. Monthly output from a high resolution numerical ocean model simulation of the North Atlantic ocean for the period 1990-2015 is used to investigate this phenomenon. It is found that the model shows skill in simulating the anomaly fields derived from various sources of data, and the observed warming trend over the last decade. From analysis of the model run it is found that the anomalies originate from the interaction between the Gulf Stream and the Labrador Current at the tail of the Grand Banks (south of Newfoundland). This interaction results in the creation of anomalous warm/salty (or cold/fresh) eddies that travel east-to-west along the shelfbreak. These anomalies penetrate into the Gulf of St. Lawrence, onto the Scotian Shelf, and into the Gulf of Maine via deep channels along the shelfbreak. The observed warming trend can be attributed to an increase in the frequency of creation of warm anomalies during the last decade. Strong anomalous events are commonly observed in the data and model, and thus should be considered as part of the natural variability of the coupled atmosphere-ocean system.

The Pennsylvanian-early permian bird spring carbonate shelf, Southeastern California: Fusulinid biostratigraphy, paleogeographic evolution, and tectonic implications

USGS Publications Warehouse

Stevens, C.H.; Stone, P.

2007-01-01

transported eastward on the Last Chance thrust. By middle Sakmarian (middle middle Wolfcampian) time (within Fusulinid Zone 4), emplacement of the Last Chance allochthon was complete, and subsidence caused by thrust loading had resulted in development of a new turbidite basin (Darwin Basin) along the former western part of the Bird Spring Shelf. At the same time, farther east into the craton, paralic facies began prograding westward, so that the youngest fusulinid-bearing limestones on the shelf in this area become progressively younger to the west. Eventually, in Artinskian to Kungurian (late Wolfcampian to Leonardian) time (Fusulinid Zones 5 and 6), deposition of fusulinid-bearing limestone on the shelf was restricted to a marginal belt between the prograding paralic facies to the east and the Darwin Basin to the west. Development of the Keeler Basin in Pennsylvanian to earliest Permian time was approximately coeval with collision between South America-Africa (Gondwana) and North America (Laurentia) on the Ouachita-Marathon orogenic belt. This basin developed inboard of a northwest-trending, sinistral fault zone that truncated the continental margin. Later, in the Early Permian, the Last Chance allochthon, which was part of a northeast-trending belt of deformation that extended into northeastern Nevada, was emplaced. This orogenic belt probably was driven by convergence at the continental margin to the northwest. This work adds significant detail to existing interpretations of the late Paleozoic as a time of major tectonic instability on the continental margin of southeastern California as it changed from a relatively passive margin that had characterized most of the Paleozoic to an active convergent margin that would characterize the Mesozoic. ?? 2007 The Geological Society of America. All rights reserved.

Contraindications in planned home birth in Iceland: A retrospective cohort study.

PubMed

Halfdansdottir, Berglind; Hildingsson, Ingegerd; Smarason, Alexander Kr; Sveinsdottir, Herdis; Olafsdottir, Olof A

2018-03-01

Icelandic national guidelines on place of birth list contraindications for home birth. Few studies have examined the effect of contraindication on home birth, and none have done so in Iceland. The aim of this study was to examine whether contraindications affect the outcome of planned home birth or have a different effect at home than in hospital. The study is a retrospective cohort study on the effect of contraindications for home birth on the outcome of planned home (n = 307) and hospital (n = 921) birth in 2005-2009. Outcomes were described for four different groups of women, by exposure to contraindications (unexposed vs. exposed) and planned place of birth (hospital vs. home). Linear and logistic regression analysis was used to evaluate the effect of the contraindications under study and to detect interactions between contraindications and planned place of birth. The key findings of the study were that contraindications were related to higher rates of adverse maternal and neonatal outcomes, regardless of place of birth; women exposed to contraindications had higher rates of adverse outcomes in planned home birth; and healthy, unexposed women had higher rates of adverse outcomes in planned hospital birth. Contraindications significantly increased the risk of transfer in labour and postpartum haemorrhage in planned home births. The defined contraindications for home birth had a negative effect on maternal and neonatal outcomes in Iceland, regardless of place of birth. The study results do not contradict the current national guidelines on place of birth. Copyright © 2017 Elsevier B.V. All rights reserved.

"Let's Go Outside": Icelandic Teachers' Views of Using the Outdoors

ERIC Educational Resources Information Center

Norðdahl, Kristín; Jóhannesson, Ingólfur Ásgeir

2016-01-01

This article discusses the views of 25 Icelandic preschool and compulsory school teachers who were interviewed on the role of the outdoor environment in children's learning. The teachers reported not being afraid to take children outside. These teachers valued the learning potentials of the outdoors more than they feared the possible risks. They…

Ice-shelf melting around Antarctica

NASA Astrophysics Data System (ADS)

Rignot, E.; Jacobs, S.

2008-12-01

The traditional view on the mass balance of Antarctic ice shelves is that they loose mass principally from iceberg calving with bottom melting a much lower contributing factor. Because ice shelves are now known to play a fundamental role in ice sheet evolution, it is important to re-evaluate their wastage processes from a circumpolar perspective using a combination of remote sensing techniques. We present area average rates deduced from grounding line discharge, snow accumulation, firn depth correction and ice shelf topography. We find that ice shelf melting accounts for roughly half of ice-shelf ablation, with a total melt water production of 1027 Gt/yr. The attrition fraction due to in-situ melting varies from 9 to 90 percent around Antarctica. High melt producers include the Ronne, Ross, Getz, Totten, Amery, George VI, Pine Island, Abbot, Dotson/Crosson, Shackleton, Thwaites and Moscow University Ice Shelves. Low producers include the Larsen C, Princess Astrid and Ragnhild coast, Fimbul, Brunt and Filchner. Correlation between melt water production and grounding line discharge is low (R2 = 0.65). Correlation with thermal ocean forcing from the ocean are highest in the northern parts of West Antarctica where regressions yield R2 of 0.93-0.97. Melt rates in the Amundsen Sea exhibit a quadratic sensitivity to thermal ocean forcing. We conclude that ice shelf melting plays a dominant role in ice shelf mass balance, with a potential to change rapidly in response to altered ocean heat transport onto the Antarctic continental shelf.

Magma-tectonic interactions in an area of active extension; a review of recent observations, models and interpretations from Iceland

NASA Astrophysics Data System (ADS)

Pedersen, Rikke; Sigmundsson, Freysteinn; Drouin, Vincent; Rafn Heimisson, Elías; Parks, Michelle; Dumont, Stéphanie; Árnadóttir, Þóra; Masterlark, Timothy; Ófeigsson, Benedíkt G.; Jónsdóttir, Kristín; Hooper, Andrew

2016-04-01

The geological setting of Iceland provides rich opportunities of studying magma-tectonic interactions, as it constitutes Earth's largest part of the mid-oceanic ridge system exposed above sea level. A series of volcanic and seismic zones accommodate the ~2 cm/year spreading between the North-American and Eurasian plates, and the Icelandic hot-spot conveniently provides the means of exposing this oceanic crust-forming setting above sea-level. Both extinct and active plumbing system structures can be studied in Iceland, as the deeply eroded tertiary areas provide views into the structures of extinct volcanic systems, and active processes can be inferred on in the many active volcanic systems. A variety of volcanic and tectonic processes cause the Icelandic crust to deform continuously, and the availability of contemporaneous measurements of crustal deformation and seismicity provide a powerful data set, when trying to obtain insight into the processes working at depth, such as magma migration through the uppermost lithosphere, magma induced host rock deformation and volcanic eruption locations and styles. The inferences geodetic and seismic datasets allow on the active plate spreading processes and subsurface magma movements in Iceland will be reviewed, in particular in relation to the Northern Volcanic Zone (NVZ). There the three phases of a rifting cycle (rifting, post-rifting, inter-rifting) have been observed. The NVZ is an extensional rift segment, bounded to the south by the Icelandic mantle plume, and to the north by the Tjörnes transform zone. The NVZ has typically been divided into five partly overlapping en-echelon fissure swarms, each with a central main volcanic production area. Most recently, additional insight into controlling factors during active rifting has been provided by the Bárðarbunga activity in 2014-2015 that included a major rifting event, the largest effusive eruption in Iceland since 1783, and a gradual caldera collapse. It is evident

Abundance and isotope systematics of carbon in subglacial basalts, geothermal gases and fluids from Iceland's rift zones

NASA Astrophysics Data System (ADS)

Barry, P. H.; Hilton, D. R.; Fueri, E.; Halldorsson, S. A.; Fischer, T. P.; Gronvold, K.

2010-12-01

P. H. BARRY1*, D. R. HILTON1, E. FÜRI1, S.A. HALLDÓRSON1, T.P. FISCHER2, K. GRONVOLD3 1 Scripps Institution of Oceanography, UCSD, La Jolla, California 92093, USA (*Correspondence: pbarry@ucsd.edu). 2University of New Mexico, Albuquerque, NM 87131, USA. 3University of Iceland, Askja, Sturlugata 7, IS-101, Reykjavik, Iceland Carbon dioxide (CO2) is the dominant non-aqueous volatile species found in oceanic basalts and geothermal fluids and serves as the carrier gas for trace volatiles such as He and other noble gases. The aim of this study is to identify the superimposed effects of degassing and crustal contamination on the CO2 systematics of the Icelandic hotspot in order to reveal and characterize the carbon abundance and isotopic features of the underlying mantle source. Our approach involves coupling CO2 with He, utilizing the sensitivity of 3He/4He ratios to reveal mantle and crustal inputs. We report new C-isotope (δ13C) and abundance characteristics for a suite of 47 subglacial basalts and 50 geothermal gases and fluids from Iceland. CO2 contents in hyaloclastite glasses are extremely low (10-100 ppm) and likely residual following extensive degassing whereas geothermal fluids are dominated by CO2 (>90 %). C-isotopes range from -27.2 to -3.6 ‰ (vs. PDB) for basalts and from -18.8 to 2.86 ‰ (vs. PDB) for geothermal samples (mean = -4.2 ± 3.6 ‰). CO2/3He ratios range from 108 to 1012 for basalts and from 105 to 1012 for geothermal samples: In both cases, our results extend He-CO2 relationships over a much broader range than reported previously [1]. Taken together, these data suggest that several processes including mixing, degassing, and/or syn- or post-eruptive crustal contamination may act to modify CO2 source characteristics. Equilibrium degassing models are compatible with ~75 % of the basalt data, and preliminary results indicate that initial Icelandic source characteristics are ~500 ppm CO2 and δ13C ~ -5 ‰ (vs. PDB). These values are high

"The Fact that I'm a Woman May Have Been the Defining Factor": The Moral Dilemmas of an Icelandic Headteacher

ERIC Educational Resources Information Center

Larusdottir, Steinunn Helga

2007-01-01

This article reports on the values and moral dilemmas of one Icelandic headteacher. The article draws on doctoral research currently being conducted with educational leaders in Icelandic basic schools. The research explores the values underpinning the work of female and male educational leaders and how values impact upon their actions, in…

Semi-supervised morphosyntactic classification of Old Icelandic.

PubMed

Urban, Kryztof; Tangherlini, Timothy R; Vijūnas, Aurelijus; Broadwell, Peter M

2014-01-01

We present IceMorph, a semi-supervised morphosyntactic analyzer of Old Icelandic. In addition to machine-read corpora and dictionaries, it applies a small set of declension prototypes to map corpus words to dictionary entries. A web-based GUI allows expert users to modify and augment data through an online process. A machine learning module incorporates prototype data, edit-distance metrics, and expert feedback to continuously update part-of-speech and morphosyntactic classification. An advantage of the analyzer is its ability to achieve competitive classification accuracy with minimum training data.

Geostatistical Analyses of Interactions between Minke Whales (Balaenoptera acutorostrata) and Whale-Watching Boats in Skjalfandi Bay, Northeast Iceland

NASA Astrophysics Data System (ADS)

Cummings, Joshua I.

The Icelandic whale-watching industry has experienced rapid growth since its inception in 1991, and today represents the fastest growing economic activity of the country. Skjalfandi Bay in Northeast Iceland has become the epicenter of whale-watching in Iceland, yet little is known about the local effects of the whale-watching industry on cetaceans. I used theodolite techniques and GIS to examine boat effects on the swimming speed, directionality, inter-breath intervals, and surface feeding events of minke whales (Balaenoptera acutorostrata) in Skjalfandi Bay. The proximity and number of vessels did not have a statistically significant effect on any aspect of minke behavior. These results contradict a previous study from Faxafloi Bay, suggesting that differences exist between the two locations, and that management strategies may need to be location-specific.

Ambient noise tomography reveals upper crustal structure of Icelandic rifts

NASA Astrophysics Data System (ADS)

Green, Robert G.; Priestley, Keith F.; White, Robert S.

2017-05-01

The structure of oceanic spreading centres and subsurface melt distribution within newly formed crust is largely understood from marine seismic experiments. In Iceland, however, sub-aerial rift elevation allows both accurate surface mapping and the installation of large broadband seismic arrays. We present a study using ambient noise Rayleigh wave tomography to image the volcanic spreading centres across Iceland. Our high resolution model images a continuous band of low seismic velocities, parallelling all three segments of the branched rift in Iceland. The upper 10 km contains strong velocity variations, with shear wave velocities 0.5 km s-1 faster in the older non-volcanically active regions compared to the active rifts. Slow velocities correlate very closely with geological surface mapping, with contours of the anomalies parallelling the edges of the neo-volcanic zones. The low-velocity band extends to the full 50 km width of the neo-volcanic zones, demonstrating a significant contrast with the narrow (8 km wide) magmatic zone seen at fast spreading ridges, where the rate of melt supply is similarly high. Within the seismically slow rift band, the lowest velocity cores of the anomalies occur above the centre of the mantle plume under the Vatnajökull icecap, and in the Eastern Volcanic Zone under the central volcano Katla. This suggests localisation of melt accumulation at these specific volcanic centres, demonstrating variability in melt supply into the shallow crust along the rift axis. Shear velocity inversions with depth show that the strongest velocity contrasts are found in the upper 8 km, and show a slight depression in the shear velocity through the mid crust (10-20 km) in the rifts. Our model also shows less intensity to the slow rift anomaly in the Western Volcanic Zone, supporting the notion that rift activity here is decreasing as the ridge jumps to the Eastern Volcanic Zone.

Is earthquake rate in south Iceland modified by seasonal loading?

NASA Astrophysics Data System (ADS)

Jonsson, S.; Aoki, Y.; Drouin, V.

2017-12-01

Several temporarily varying processes have the potential of modifying the rate of earthquakes in the south Iceland seismic zone, one of the two most active seismic zones in Iceland. These include solid earth tides, seasonal meteorological effects and influence from passing weather systems, and variations in snow and glacier loads. In this study we investigate the influence these processes may have on crustal stresses and stressing rates in the seismic zone and assess whether they appear to be influencing the earthquake rate. While historical earthquakes in the south Iceland have preferentially occurred in early summer, this tendency is less clear for small earthquakes. The local earthquake catalogue (going back to 1991, magnitude of completeness < 1.0) has indeed more earthquakes in summer than in winter. However, this pattern is strongly influenced by aftershock sequences of the largest M6+ earthquakes, which occurred in June 2000 and May 2008. Standard Reasenberg earthquake declustering or more involved model independent stochastic declustering algorithms are not capable of fully eliminating the aftershocks from the catalogue. We therefore inspected the catalogue for the time period before 2000 and it shows limited seasonal tendency in earthquake occurrence. Our preliminary results show no clear correlation between earthquake rates and short-term stressing variations induced from solid earth tides or passing storms. Seasonal meteorological effects also appear to be too small to influence the earthquake activity. Snow and glacier load variations induce significant vertical motions in the area with peak loading occurring in Spring (April-May) and maximum unloading in Fall (Sept.-Oct.). Early summer occurrence of historical earthquakes therefore correlates with early unloading rather than with the peak unloading or unloading rate, which appears to indicate limited influence of this seasonal process on the earthquake activity.

Cognitive Profile in Young Icelandic Children with Cerebral Palsy

ERIC Educational Resources Information Center

Sigurdardottir, Solveig; Eiriksdottir, Audur; Gunnarsdottir, Eva; Meintema, Marrit; Arnadottir, Unnur; Vik, Torstein

2008-01-01

We describe the cognitive profile in a complete national cohort of children with cerebral palsy (CP). One hundred and twenty-seven Icelandic children (67 females, 60 males) with CP, born between 1985 and 2000 and assessed between the ages of 4 and 6 years 6 months (mean age 5y 5mo, SD 6mo), were included in the study. IQ was measured using the…

Students' Attitudes towards Craft and Technology in Iceland and Finland

ERIC Educational Resources Information Center

Thorsteinsson, Gísli; Ólafsson, Brynjar; Autio, Ossi

2012-01-01

Craft education in both Finland and Iceland originated over 140 years ago and was influenced by the Scandinavian Sloyd pedagogy. Since then, the subject has moved away from craft and towards technology, with the aim being to increase students' technological abilities. In the beginning, the subject largely focused on the students copying artefacts,…

Multibeam mapping of the West Florida Shelf, Gulf of Mexico

USGS Publications Warehouse

Gardner, James V.; Dartnell, Peter; Sulak, Kenneth J.

2002-01-01

A zone of deep-water reefs is thought to extend from the mid and outer shelf south of Mississippi and Alabama to at least the northwestern Florida shelf off Panama City, Florida (Figure 1). The reefs off Mississippi and Alabama are found in water depths of 60 to 120 m (Ludwick and Walton, 1957; Gardner et al., 2001, in press) and were the focus of a multibeam echosounder (MBES) mapping survey by the U.S. Geological Survey (USGS) in 2000 (Gardner et al., 2000, Gardner et al., 2001, in press). If this deep-water-reef trend does exist along the northwestern Florida shelf, then it is critical to determine the accurate geomorphology and reef type that occur because of their importance as benthic habitats for fisheries. Georeferenced high-resolution mapping of bathymetry is a fundamental first step in the study of areas suspected to be critical habitats. Morphology is thought to be critical to defining the distribution of dominant demersal plankton/planktivores communities. Fish faunas of shallow hermatypic reefs have been well studied, but those of deep ahermatypic reefs have been relatively ignored. The ecology of deep-water ahermatypic reefs is fundamentally different from hermatypic reefs because autochthonous intracellular symbiotic zooxanthellae (the carbon source for hermatypic corals) do not form the base of the trophic web in ahermatypic reefs. Instead, exogenous plankton, transported to the reef by currents, serves as the primary carbon source. Thus, one of the principle uses of the morphology data will be to identify whether any reefs found are hermatypic or ahermatypic in origin.

Seafloor geology of the Monterey Bay area continental shelf

USGS Publications Warehouse

Eittreim, S.L.; Anima, R.J.; Stevenson, A.J.

2002-01-01

Acoustic swath-mapping of the greater Monterey Bay area continental shelf from Point An??o Nuevo to Point Sur reveals complex patterns of rock outcrops on the shelf, and coarse-sand bodies that occur in distinct depressions on the inner and mid-shelves. Most of the rock outcrops are erosional cuestas of dipping Tertiary rocks that make up the bedrock of the surrounding lands. A mid-shelf mud belt of Holocene sediment buries the Tertiary rocks in a continuous, 6-km-wide zone on the northern Monterey Bay shelf. Rock exposures occur on the inner shelf, near tectonically uplifting highlands, and on the outer shelf, beyond the reach of the mud depositing on the mid-shelf since the Holocene sea-level rise. The sediment-starved shelf off the Monterey Peninsula and south to Point Sur has a very thin cover of Holocene sediment, and bedrock outcrops occur across the whole shelf, with Salinian granite outcrops surrounding the Monterey Peninsula. Coarse-sand deposits occur both bounded within low-relief rippled scour depressions, and in broad sheets in areas like the Sur Platform where fine sediment sources are limited. The greatest concentrations of coarse-sand deposits occur on the southern Monterey Bay shelf and the Sur shelf. ?? 2002 Elsevier Science B.V. All rights reserved.

Origins of terrestrial organic matter in surface sediments of the East China Sea shelf

NASA Astrophysics Data System (ADS)

Zhang, Hailong; Xing, Lei; Zhao, Meixun

2017-10-01

Terrestrial organic matter (TOM) is an important component of marine sedimentary OM, and revealing the origins and transport mechanisms of TOM to the East China Sea (ECS) is important for understanding regional carbon cycle. A novel approach combining molecular proxies and compound-specific carbon isotopes is used to quantitatively constrain the origins and transport mechanisms of TOM in surface sediments from the ECS shelf. The content of terrestrial biomarkers of (C27+C29+C31) n-alkanes (52 to 580 ng g-1) revealed a seaward decreasing trend, the δ13CTOC values (-20.6‰ to -22.7‰) were more negative near the coast, and the TMBR (terrestrial and marine biomarker ratio) values (0.06 to 0.40) also revealed a seaward decreasing trend. These proxies all indicated more TOM (up to 48%) deposition in the coastal areas. The Alkane Index, the ratio of C29/(C29+C31) n-alkanes indicated a higher proportion of grass vegetation in the coastal area; While the δ13C values of C29 n-alkane (-29.3‰ to -33.8‰) indicated that terrestrial plant in the sediments of the ECS shelf were mainly derived from C3 plants. Cluster analysis afforded detailed estimates of different-sourced TOM contributions and transport mechanisms. TOM in the Zhejiang-Fujian coastal area was mostly delivered by the Changjiang River, and characterized by higher %TOM (up to 48%), higher %C3 plant OM (68%-85%) and higher grass plant OM (56%-61%); TOM in the mid-shelf area was mostly transported by aerosols, and characterized by low %TOM (less than 17%), slightly lower C3 plant OM (56%-72%) and lower grass plant OM (49%-55%).

The effects of sub-ice-shelf melting on dense shelf water formation and export in idealized simulations of Antarctic margins

NASA Astrophysics Data System (ADS)

Marques, Gustavo; Stern, Alon; Harrison, Matthew; Sergienko, Olga; Hallberg, Robert

2017-04-01

Dense shelf water (DSW) is formed in coastal polynyas around Antarctica as a result of intense cooling and brine rejection. A fraction of this water reaches ice shelves cavities and is modified due to interactions with sub-ice-shelf melt water. This modified water mass contributes to the formation of Antarctic Bottom Water, and consequently, influences the large-scale ocean circulation. Here, we investigate the role of sub-ice-shelf melting in the formation and export of DSW using idealized simulations with an isopycnal ocean model (MOM6) coupled with a sea ice model (SIS2) and a thermodynamic active ice shelf. A set of experiments is conducted with variable horizontal grid resolutions (0.5, 1.0 and 2.0 km), ice shelf geometries and atmospheric forcing. In all simulations DSW is spontaneously formed in coastal polynyas due to the combined effect of the imposed atmospheric forcing and the ocean state. Our results show that sub-ice-shelf melting can significantly change the rate of dense shelf water outflows, highlighting the importance of this process to correctly represent bottom water formation.

Deep crustal melt plumbing of Bárðarbunga volcano, Iceland

NASA Astrophysics Data System (ADS)

Hudson, T. S.; White, R. S.; Greenfield, T.; Ágústsdóttir, T.; Brisbourne, A.; Green, R. G.

2017-09-01

Understanding magmatic plumbing within the Earth's crust is important for understanding volcanic systems and improving eruption forecasting. We discuss magma plumbing under Bárðarbunga volcano, Iceland, over a 4 year period encompassing the largest Icelandic eruption in 230 years. Microseismicity extends through the usually ductile region of the Earth's crust, from 7 to 22 km depth in a subvertical column. Moment tensor solutions for an example earthquake exhibits opening tensile crack behavior. This is consistent with the deep (>7 km) seismicity being caused by the movement of melt in the normally aseismic crust. The seismically inferred melt path from the mantle source is offset laterally from the center of the Bárðarbunga caldera by 12 km, rather than lying directly beneath it. It is likely that an aseismic melt feed also exists directly beneath the caldera and is aseismic due to elevated temperatures and pervasive partial melt under the caldera.

Iceland's Central Highlands: Nature conservation, ecotourism, and energy resource utilization

Treesearch

Bjorn Gunnarsson; Maria-Victoria Gunnarsson

2002-01-01

Iceland’s natural resources include an abundance of geothermal energy and hydropower, of which only 10 to 15 percent is currently being utilized. These are clean, renewable sources of energy. The cost to convert these resources to electricity is relatively low, making them attractive and highly marketable for industrial development, particularly for heavy industry....

The paleointensity record of Icelandic subglacial volcanic glasses and recent lavas

NASA Astrophysics Data System (ADS)

Cromwell, G.; Tauxe, L.; Halldorsson, S. A.

2013-05-01

The Earth's ancient magnetic field can be approximated by a geocentric axial dipole (GAD) where the average field intensity is twice as strong at the poles than at the equator. The present day geomagnetic field, and some global paleointensity datasets, support the GAD hypothesis with a virtual axial dipole moment (VADM) of about 80 ZAm2 , which corresponds to surface field intensities of ~30 μT and 60 μT at the equator and poles, respectively. An astounding departure from the GAD hypothesis is found in Antarctica where the average field strength for 0-5 Ma (31.5 ± 2.4 μT, 78° S (1)) is equivalent to predictions at the Earth's equator. Proposed explanations for this decidedly non-GAD behavior at high southern latitudes include incomplete temporal sampling, effects from the tangent cylinder, and hemispheric asymmetry (especially at high latitudes). A comparison of Arctic and Antarctic paleointensity data over similar timescales might offer insights into the GAD field, however northern high latitude data comparable to the Antarctic collection are sparse due to the lack of young (0-5 Ma) and accessible lava flows. One exception is Iceland, a volcanic island on the Mid-Atlantic Ridge with continuous volcanism for the last ~15 Ma. Many of the paleointensity studies from Iceland target very young lavas (Holocene age) or transitional geomagnetic field states, both of which offer limited analysis of the long-term geomagnetic field. Additionally, some studies employ experimental methods that do not provide tests for alteration or other irreversible magnetic behaviors that can occur during multiple high temperature heating steps. We present a detailed collection of Icelandic paleointensity records from 85 volcanic units ranging in age from 1783 C.E. to ~4 Ma. We sample volcanic glass from flow tops and subglacially erupted volcanic units in order to collect single-domain magnetic material, which has been shown to accurately record magnetic field strength (2). Preliminary

Causes and consequences of hypoxia on the Western Black Sea Shelf

NASA Astrophysics Data System (ADS)

Friedrich, Jana; Gomoiu, Marian-Trajan; Naeher, Sebastian; Secrieru, Dan; Teaca, Adrian

2013-04-01

The Black Sea, containing the world's largest natural anoxic basin since ca 7500 years (Jones & Gagnon 1994), suffers from combined effects of anthropogenic eutrophication, overfishing and climate variability (Oguz & Gilbert 2007). We discuss causes for hypoxia in western shelf waters. Freshwater runoff by the large rivers Danube, Dniester and Dnieper results in strong thermohaline stratification that limits bottom water ventilation on the north-western shelf during warm seasons. This makes the western shelf generally prone to oxygen deficiency. During autumn and winter, the thermohaline stratification is eroded by frequent storms and the water column is re-oxygenated. The causal chain of anthropogenic eutrophication since the 1970s led to seasonal hypoxia on the western shelf for more than 20 years causing the catastrophic decline of key shelf habitats (Mee et al. 2005). More frequent and intense algal blooms, red tides (i.e. Noctiluca, Prorocentrum cordatum) and changes in species composition in phytoplankton resulted in deposition of surplus organic matter on the seafloor increasing the oxygen demand, with serious consequences for pelagic and benthic ecosystem structure and functioning. During hypoxia, release of reduced substances like ammonia and phosphate from the sediment to the water fuelled eutrophication internally (Friedrich et al. 2002). The combination of existing data with those gained during EU FP7 HYPOX on the Romanian shelf enables to assess the development of bottom water hypoxia and changes in benthic community and hence, the current state and trends in recovery of the Romanian Black Sea shelf ecosystem. Mud worms are the winners of eutrophication and hypoxia, whereas filter feeders like Mytilus galloprovincialis and Acanthocardia paucicostata are the losers. The western shelf benthic ecosystem showed a significant reduction in species diversity, a reduction of biofilter strength due to the loss of filter-feeder populations and flourishing of

Shelf Reading as a Collaborative Service Model

ERIC Educational Resources Information Center

Brown, Kevin N.; Kaspar, Wendi Arant

2006-01-01

Shelf reading the stacks is very often not seen as scholarly work in library circles and is therefore overlooked. However, there is a very real frustration of a patron who cannot find the material they need. There are very few studies that provide a working model for shelf reading. The authors suggest a collaborative shelf reading model based on…

How ice shelf morphology controls basal melting

NASA Astrophysics Data System (ADS)

Little, Christopher M.; Gnanadesikan, Anand; Oppenheimer, Michael

2009-12-01

The response of ice shelf basal melting to climate is a function of ocean temperature, circulation, and mixing in the open ocean and the coupling of this external forcing to the sub-ice shelf circulation. Because slope strongly influences the properties of buoyancy-driven flow near the ice shelf base, ice shelf morphology plays a critical role in linking external, subsurface heat sources to the ice. In this paper, the slope-driven dynamic control of local and area-integrated melting rates is examined under a wide range of ocean temperatures and ice shelf shapes, with an emphasis on smaller, steeper ice shelves. A 3-D numerical ocean model is used to simulate the circulation underneath five idealized ice shelves, forced with subsurface ocean temperatures ranging from -2.0°C to 1.5°C. In the sub-ice shelf mixed layer, three spatially distinct dynamic regimes are present. Entrainment of heat occurs predominately under deeper sections of the ice shelf; local and area-integrated melting rates are most sensitive to changes in slope in this "initiation" region. Some entrained heat is advected upslope and used to melt ice in the "maintenance" region; however, flow convergence in the "outflow" region limits heat loss in flatter portions of the ice shelf. Heat flux to the ice exhibits (1) a spatially nonuniform, superlinear dependence on slope and (2) a shape- and temperature-dependent, internally controlled efficiency. Because the efficiency of heat flux through the mixed layer decreases with increasing ocean temperature, numerical simulations diverge from a simple quadratic scaling law.

Microbiological Analysis in Three Diverse Natural Geothermal Bathing Pools in Iceland

PubMed Central

Thorolfsdottir, Berglind Osk Th.; Marteinsson, Viggo Thor

2013-01-01

Natural thermal bathing pools contain geothermal water that is very popular to bathe in but the water is not sterilized, irradiated or treated in any way. Increasing tourism in Iceland will lead to increasing numbers of bath guests, which can in turn affect the microbial flora in the pools and therefore user safety. Today, there is no legislation that applies to natural geothermal pools in Iceland, as the water is not used for consumption and the pools are not defined as public swimming pools. In this study, we conducted a microbiological analysis on three popular but different natural pools in Iceland, located at Lýsuhóll, Hveravellir and Landmannalaugar. Total bacterial counts were performed by flow cytometry, and with plate count at 22 °C, 37 °C and 50 °C. The presence of viable coliforms, Enterococcus spp. and pseudomonads were investigated by growth experiments on selective media. All samples were screened for noroviruses by real time PCR. The results indicate higher fecal contamination in the geothermal pools where the geothermal water flow was low and bathing guest count was high during the day. The number of cultivated Pseudomonas spp. was high (13,000–40,000 cfu/100 mL) in the natural pools, and several strains were isolated and classified as opportunistic pathogens. Norovirus was not detected in the three pools. DNA was extracted from one-liter samples in each pool and analyzed by partial 16S rRNA gene sequencing. Microbial diversity analysis revealed different microbial communities between the pools and they were primarily composed of alpha-, beta- and gammaproteobacteria. PMID:23493033

The impact of past climate change on genetic variation and population connectivity in the Icelandic arctic fox

PubMed Central

Mellows, Andrew; Barnett, Ross; Dalén, Love; Sandoval-Castellanos, Edson; Linderholm, Anna; McGovern, Thomas H.; Church, Mike J.; Larson, Greger

2012-01-01

Previous studies have suggested that the presence of sea ice is an important factor in facilitating migration and determining the degree of genetic isolation among contemporary arctic fox populations. Because the extent of sea ice is dependent upon global temperatures, periods of significant cooling would have had a major impact on fox population connectivity and genetic variation. We tested this hypothesis by extracting and sequencing mitochondrial control region sequences from 17 arctic foxes excavated from two late-ninth-century to twelfth-century AD archaeological sites in northeast Iceland, both of which predate the Little Ice Age (approx. sixteenth to nineteenth century). Despite the fact that five haplotypes have been observed in modern Icelandic foxes, a single haplotype was shared among all of the ancient individuals. Results from simulations within an approximate Bayesian computation framework suggest that the rapid increase in Icelandic arctic fox haplotype diversity can only be explained by sea-ice-mediated fox immigration facilitated by the Little Ice Age. PMID:22977155

The impact of past climate change on genetic variation and population connectivity in the Icelandic arctic fox.

PubMed

Mellows, Andrew; Barnett, Ross; Dalén, Love; Sandoval-Castellanos, Edson; Linderholm, Anna; McGovern, Thomas H; Church, Mike J; Larson, Greger

2012-11-22

Previous studies have suggested that the presence of sea ice is an important factor in facilitating migration and determining the degree of genetic isolation among contemporary arctic fox populations. Because the extent of sea ice is dependent upon global temperatures, periods of significant cooling would have had a major impact on fox population connectivity and genetic variation. We tested this hypothesis by extracting and sequencing mitochondrial control region sequences from 17 arctic foxes excavated from two late-ninth-century to twelfth-century AD archaeological sites in northeast Iceland, both of which predate the Little Ice Age (approx. sixteenth to nineteenth century). Despite the fact that five haplotypes have been observed in modern Icelandic foxes, a single haplotype was shared among all of the ancient individuals. Results from simulations within an approximate Bayesian computation framework suggest that the rapid increase in Icelandic arctic fox haplotype diversity can only be explained by sea-ice-mediated fox immigration facilitated by the Little Ice Age.

Comparing the composition of the earliest basalts erupted by the Iceland and Afar mantle plumes.

NASA Astrophysics Data System (ADS)

Stuart, Finlay M.

2013-04-01

The first basalts erupted by mantle plumes are typically generated by mantle melting at temperatures 200-300°C higher than average ambient mantle. This is consistent with the derivation of from a thermal boundary layer at the core-mantle boundary. Mantle plume temperatures decrease with time, likely as large plume heads give way to thin plume conduits. Consequently the early, hot plume basalts are a window into the deep mantle. At it's simplest they provide a test of whether the discrete plume source regions are primordial mantle that have been isolated since soon after Earth accretion, or have substantial contributions from subducted slabs. Here I present new isotopic and trace element determinations of the earliest picritic basalts from the ~30 Ma Afar plume in Ethiopia. They will be compared with similar material from the ~60 Ma proto-Iceland plume (PIP) in an effort to test prevailing models regarding the source of mantle plumes. The extremely primordial nature of the helium in the PIP picrites (3He/4He ~ 50 Ra) contrasts with much lower values of the Ethiopian flood basalt province (~21 Ra). The Iceland plume 3He/4He has decreased (linearly) with time, mirroring the secular cooling of the Iceland mantle plume identified by decreasing MgO and FeO in primary melts. In 60 million years the Iceland plume 3He/4He is still higher than the maximum Afar plume value. The Sr-Nd-Pb isotopic composition of the high 3He/4He Ethiopian flood basalt province picrites are remarkably homogenous (e.g. 87Sr/86Sr = 0.70396-0.70412; 206Pb/204Pb = 18.82-19.01). In comparison the PIP picrites have ranges that span nearly the global range of E-MORB and N-MORB. The Afar and proto-Iceland mantle plumes are clearly not initiated in a single deep mantle domain with the same depletion/enrichment and degassing histories, and the same scale of heterogeneity. This implies that there is more than one plume source region/mechanism that is capable of generating comparable volumes of basalt melt

Ice-shelf Dynamics Near the Front of Filchner-Ronne Ice Shelf, Antarctica, Revealed by SAR Interferometry

NASA Technical Reports Server (NTRS)

Rignot, E.; MacAyeal, D. R.

1998-01-01

Fifteen synthetic-aperture radar (SAR) images of the Ronne Ice Shelf, Antarctica, obtained by the European Space Agency (ESA)'s Earth Remote Sensing satellites (ERS) 1 & 2 are used to study ice-shelf dynamics near two ends of the iceberg-calving front.

A quantitative X-ray diffraction inventory of the tephra and volcanic glass inputs into the Holocene marine sediment archives off Iceland: A contribution to V.A.S.T.

USGS Publications Warehouse

Andrews, John T.; Kristjansdottir, Greta B.; Eberl, Dennis D.; Jennings, Anne E.

2013-01-01

This paper re-evaluates how well quantitative x-ray diffraction (qXRD) can be used as an exploratory method of the weight percentage (wt%) of volcaniclastic sediment, and to identify tephra events in marine cores. In the widely used RockJock v6 software programme, qXRD tephra and glass standards include the rhyodacite White River tephra (Alaska), a rhyolitic tephra (Hekla-4) and the basaltic Saksunarvatn tephra. Experiments of adding known wt% of tephra to felsic bedrock samples indicated that additions ≥10 wt% are accurately detected, but reliable estimates of lesser amounts are masked by amorphous material produced by milling. Volcaniclastic inputs range between 20 and 50 wt%. Primary tephra events are identified as peaks in residual qXRD glass wt% from fourth-order polynomial fits. In cores where tephras have been identified by shard counts in the > 150 µm fraction, there is a positive correlation (validation) with peaks in the wt% glass estimated by qXRD. Geochemistry of tephra shards confirms the presence of several Hekla-sourced tephras in cores B997-317PC1 and -319PC2 on the northern Iceland shelf. In core B997-338 (north-west Iceland), there are two rhyolitic tephras separated by ca. 100 cm with uncorrected radiocarbon dates on articulated shells of around 13 000 yr B.P. These tephras may be correlatives of the Borrobol and Penifiler tephras found in Scotland. The number of Holocene tephra events per 1000 yr was estimated from qXRD on 16 cores and showed a bimodal distribution with an increased number of events in both the late and early Holocene.

Role of CO2-forced Antarctic shelf freshening on local shelf warming in an eddying global climate model

NASA Astrophysics Data System (ADS)

Goddard, P.; Dufour, C.; Yin, J.; Griffies, S. M.; Winton, M.

2017-12-01

Ocean warming near the Antarctic ice shelves has critical implications for future ice sheet mass loss and global sea level rise. A global climate model (GFDL CM2.6) with an eddying ocean is used to quantify and better understand the mechanisms contributing to ocean warming on the Antarctic continental shelf in an idealized 2xCO2 experiment. The results indicate that the simulated shelf region warming varies in magnitude at different locations. Relatively large warm anomalies occur both in the upper 100 m and at depth, which are controlled by different mechanisms. Here, we focus on the deep shelf warming and its relationship to shelf freshening. Under CO2-forcing, enhanced runoff from Antarctica, more regional precipitation, and reduction of sea ice contribute to the shelf freshening. The freshening increases the lateral density gradient of the Antarctic Slope Front, which can limit along-isopycnal onshore transport of heat from the Circumpolar Deep Water across the shelf break. Thus, the magnitude and location of the freshening anomalies govern the magnitude and location of onshore heat transport and deep warm anomalies. Additionally, the freshening increases vertical stratification on the shelf. The enhanced stratification reduces vertical mixing of heat associated with diffusion and gravitational instabilities, further contributing to the build-up of temperature anomalies at depth. Freshening is a crucial driver of the magnitude and location of the warming; however, other drivers influence the warming such as CO2-forced weakening of the easterly wind stress and associated shoaling of isotherms. Understanding the relative role of freshening in the inhomogeneous ocean warming of the Antarctic continental shelf would lead to better projections of future ice sheet mass loss, especially near the most vulnerable calving fronts.

Learning Icelandic Language and Culture in Virtual Reykjavik: Starting to Talk

ERIC Educational Resources Information Center

Bédi, Branislav; Arnbjörnsdóttir, Birna; Vilhjálmsson, Hannes Högni; Helgadóttir, Hafdís Erla; Ólafsson, Stefán; Björgvinsson, Elías

2016-01-01

This paper describes how beginners of Icelandic as a foreign and second language responded to playing the first scene in Virtual Reykjavik, a video game-like environment where learners interact with virtual characters--Embodied Conversational Agents (ECAs). This game enables learners to practice speaking and listening skills, to learn about the…

Examining Technological Knowledge and Reasoning in Icelandic and Finnish Comprehensive Schools

ERIC Educational Resources Information Center

Autio, Ossi; Olafsson, Brynjar; Thorsteinsson, Gisli

2016-01-01

This research was undertaken in Finnish and Icelandic schools during the years 2013-14, in order to explore students' technological knowledge and reasoning at the ages of eleven and thirteen. The research considered the congruence between students' undertakings within Craft and Design education in the national curriculum and their ability to…

Possibilities in the Boy Turn? Comparative Lessons from Australia and Iceland

ERIC Educational Resources Information Center

Johannesson, Ingolfur Asgeir; Lingard, Bob; Mills, Martin

2009-01-01

Recognising that there is now a globalised educational discourse about "failing boys" circulating in the privileged nations of the global north, this article provides a comparative perspective on educational policy responses to the "boy turn" in Australia and Iceland. Specificities of the responses to the boy turn in the two…

Temperature fluctuation of the Iceland mantle plume through time

NASA Astrophysics Data System (ADS)

Spice, Holly E.; Fitton, J. Godfrey; Kirstein, Linda A.

2016-02-01

The newly developed Al-in-olivine geothermometer was used to find the olivine-Cr-spinel crystallization temperatures of a suite of picrites spanning the spatial and temporal extent of the North Atlantic Igneous Province (NAIP), which is widely considered to be the result of a deep-seated mantle plume. Our data confirm that start-up plumes are associated with a pulse of anomalously hot mantle over a large spatial area before becoming focused into a narrow upwelling. We find that the thermal anomaly on both sides of the province at Baffin Island/West Greenland and the British Isles at ˜61 Ma across an area ˜2000 km in diameter was uniform, with Al-in-olivine temperatures up to ˜300°C above that of average mid-ocean ridge basalt (MORB) primitive magma. Furthermore, by combining our results with geochemical data and existing geophysical and bathymetric observations, we present compelling evidence for long-term (>107 year) fluctuations in the temperature of the Iceland mantle plume. We show that the plume temperature fell from its initial high value during the start-up phase to a minimum at about 35 Ma, and that the mantle temperature beneath Iceland is currently increasing.

Wind-induced interannual variability of sea level slope, along-shelf flow, and surface salinity on the Northwest Atlantic shelf

NASA Astrophysics Data System (ADS)

Li, Yun; Ji, Rubao; Fratantoni, Paula S.; Chen, Changsheng; Hare, Jonathan A.; Davis, Cabell S.; Beardsley, Robert C.

2014-04-01

In this study, we examine the importance of regional wind forcing in modulating advective processes and hydrographic properties along the Northwest Atlantic shelf, with a focus on the Nova Scotian Shelf (NSS)-Gulf of Maine (GoM) region. Long-term observational data of alongshore wind stress, sea level slope, and along-shelf flow are analyzed to quantify the relationship between wind forcing and hydrodynamic responses on interannual time scales. Additionally, a simplified momentum balance model is used to examine the underlying mechanisms. Our results show significant correlation among the observed interannual variability of sea level slope, along-shelf flow, and alongshore wind stress in the NSS-GoM region. A mechanism is suggested to elucidate the role of wind in modulating the sea level slope and along-shelf flow: stronger southwesterly (northeastward) winds tend to weaken the prevailing southwestward flow over the shelf, building sea level in the upstream Newfoundland Shelf region, whereas weaker southwesterly winds allow stronger southwestward flow to develop, raising sea level in the GoM region. The wind-induced flow variability can influence the transport of low-salinity water from the Gulf of St. Lawrence to the GoM, explaining interannual variations in surface salinity distributions within the region. Hence, our results offer a viable mechanism, besides the freshening of remote upstream sources, to explain interannual patterns of freshening in the GoM.

Assessing the hydropower potential of ungauged watersheds in Iceland using hydrological modeling and satellite retrieved snow cover images

NASA Astrophysics Data System (ADS)

Finger, David

2015-04-01

About 80% of the domestic energy production in Iceland comes from renewable energies. Hydropower accounts for about 20% this production, representing about 75% of the total electricity production in Iceland. In 2008 total electricity production from hydropower was about 12.5 TWh a-1, making Iceland a worldwide leader in hydropower production per capita. Furthermore, the total potential of hydroelectricity in Iceland is estimated to amount up to 220 TWh a-1. In this regard, hydrological modelling is an essential tool to adapt a sustainable management of water resources and estimate the potential of possible new sites for hydropower production. We used the conceptual lumped Hydrologiska Byråns Vattenbalansavdelning model (HBV) to estimate the potential of hydropower production in two remote areas in north-eastern Iceland (Leirdalshraun, a 274 km2 area above 595 m asl and Hafralónsá, a 946 km2 area above 235 m asl). The model parameters were determined by calibrating the model with discharge data from gauged sub catchments. Satellite snow cover images were used to constrain melt parameters of the model and assure adequate modelling of snow melt in the ungauged areas. This was particularly valuable to adequately estimate the contribution of snow melt, rainfall runoff and groundwater intrusion from glaciers outside the topographic boundaries of the selected watersheds. Runoff from the entire area potentially used for hydropower exploitation was estimated using the parameter sets of the gauged sub-catchments. Additionally, snow melt from the ungauged areas was validated with satellite based snow cover images, revealing a robust simulation of snow melt in the entire area. Based on the hydrological modelling the total amount of snow melt and rainfall runoff available in Leirdalshraun and Hafralónsá amounts up to 700 M m3 a-1 and 1000 M m3 a-1, respectively. These results reveal that the total hydropower potential of the two sites amounts up to 1.2 TWh a-1

Antarctic sub-shelf melt rates via SIMPEL

NASA Astrophysics Data System (ADS)

Reese, Ronja; Albrecht, Torsten; Winkelmann, Ricarda

2017-04-01

Ocean-induced melting below ice-shelves is currently suspected to be the dominant cause of mass loss from the Antarctic Ice Sheet (e.g. Depoorter et al. 2013). Although thinning of ice shelves does not directly contribute to sea-level rise, it may have a significant indirect impact through the potential of ice shelves to buttress their adjacent ice sheet. Hence, an appropriate representation of sub-shelf melt rates is essential for modelling the evolution of ice sheets with marine terminating outlet glaciers. Due to computational limits of fully-coupled ice and ocean models, sub-shelf melt rates are often parametrized in large-scale or long-term simulations (e.g. Matin et al. 2011, Pollard & DeConto 2012). These parametrizations usually depend on the depth of the ice shelf base or its local slope but do not include the physical processes in ice shelf cavities. Here, we present the Sub Ice shelf Melt Potsdam modEL (SIMPEL) which mimics the first-order large-scale circulation in ice shelf cavities based on an ocean box model (Olbers & Hellmer, 2010), implemented in the Parallel Ice Sheet Model (Bueler & Brown 2009, Winkelmann et al. 2011, www.pism-docs.org). In SIMPEL, ocean water is transported at depth towards the grounding line where sub-shelf melt rates are highest, and then rises along the shelf base towards the calving front where refreezing can occur. Melt rates are computed by a description of ice-ocean interaction commonly used in high-resolution models (McPhee 1992, Holland & Jenkins 1999). This enables the model to capture a wide-range of melt rates, comparable to the observed range for Antarctic ice shelves (Rignot et al. 2013).

Shelf-Life Prediction of Chilled Foods

NASA Astrophysics Data System (ADS)

Gudmundsson, Gudmundur; Kristbergsson, Kristberg

All foods have a finite shelf life. Even foods, which mature with time, will in the end deteriorate, although their life span can exceed 100 years. Definitions of shelf life of food products differ. Some stress the suitability of the product for consump¬tion, others for how long the product can be sold. The Institute of Food Science and Technology emphasizes safety in its definition of shelf life: "The period of time under defined conditions of storage, after manufacture or packing, for which a food product will remain safe and be fit for use" ( http://www.ifst.org ). This definition does not describe what makes a food product "safe" or "fit" for use, but one can say all factors which restrict the shelf life of a food product either affect safety or quality or both.

Short-lived radium isotopes on the Scotian Shelf: Unique distribution and tracers of cross-shelf CO2 and nutrient transport

NASA Astrophysics Data System (ADS)

Burt, William; Thomas, Helmuth

2013-04-01

Radium (Ra) isotopes have become a common tool for investigating mixing rates on continental shelves, and more recently have been used to quantify the release of dissolved compounds enriched in pore-waters into the water column. We present results from Ra sampling of the Scotian Shelf region of the Canadian northwestern Atlantic Ocean, which reveal cross-shelf Ra distributions that are unique compared to other coastal regions. We explain the observations of lower 224Ra activities near the coast, relatively high activities at large distances offshore (>100km), and gradients in both offshore and onshore directions by inferring the regional geomorphology, as well as shelf bathymetry and circulation patterns. Ra gradients are used to calculate individual estimates of eddy diffusion in both the cross-shelf (KX) and vertical (KZ) directions using 1-D eddy diffusion models. Enhanced vertical mixing above offshore banks allows for Ra enrichments in offshore surface waters, while horizontal dispersion of this bank-related signal can transport Ra off the shelf break in surface waters, and towards the shore beneath the surface mixed layer. Similar onshore gradients in CO2 and nutrient species combined with Ra-derived KX values can yield onshore carbon and nutrient fluxes in subsurface waters, which in turn supply the CO2 outgassing from the Scotian Shelf. Our results thus provide constraints for cross-shelf transports of carbon and nutrients on the Scotian Shelf in order to guide mass balance or model based budget approaches in future studies.

Modulation of allergy incidence in icelandic horses is associated with a change in IL-4-producing T cells.

PubMed

Hamza, E; Doherr, M G; Bertoni, G; Jungi, T W; Marti, E

2007-01-01

Equine insect bite hypersensitivity (IBH) is an immediate-type hypersensitivity reaction provoked by insect-derived allergens. Icelandic horses living in Iceland do not have IBH due to absence of relevant insects, but acquire it at high frequency after being imported to mainland Europe. In contrast, their offspring born in mainland Europe has reduced IBH incidence. T helper 1 (Th1) and Th2 cells and cytokines were determined in Icelandic horses born in Iceland and on the continent and which either have IBH or are healthy. Peripheral blood mononuclear cells (PBMC) from these horses were stimulated for 18 h during summer and winter with polyclonal T cell stimuli, IBH allergen(s) or irrelevant allergen(s). Cells were analysed by flow cytometry for interferon-gamma (IFN-gamma) and interleukin-4 (IL-4); RNA was analysed for IFN-gamma, IL-4, IL-5 and IL-13 mRNA. During summer, but not during winter, IBH PBMC stimulated polyclonally showed reduced IFN-gamma mRNA and IFN-gamma-producing cells when compared with those of healthy horses, regardless of origin. PBMC stimulated polyclonally or with IBH allergen showed increased IL-4 mRNA levels and higher numbers of IL-4-producing cells when born in Iceland or showing IBH symptoms. IL-5 and IL-13 mRNA were modulated neither by disease nor by origin. Abrogation of IL-4 production in healthy horses born in mainland Europe may be due, at least in part, to IL-10. There was an increased level of IL-10 in supernatants from PBMC of healthy horses born in mainland Europe and stimulated polyclonally or with IBH allergen. Modulation of IBH incidence is governed by altered Th1/Th2 ratio, which might be influenced by IL-10. Copyright 2007 S. Karger AG, Basel.

A Lexical Comparison of Signs from Icelandic and Danish Sign Languages

ERIC Educational Resources Information Center

Aldersson, Russell R.; McEntee-Atalianis, Lisa J.

2008-01-01

This article reports on a comparison of lexical items in the vocabulary of Icelandic and Danish sign languages prompted by anecdotal reports of similarity and historical records detailing close contact between the two communities. Drawing on previous studies, including Bickford (2005), McKee and Kennedy (1998, 2000a, 2000b) and Parkhurst and…

Ice Front at Venable Ice Shelf

NASA Image and Video Library

2013-06-13

This photo, taken onboard the Chilean Navy P3 aircraft, shows the ice front of Venable Ice Shelf, West Antarctica, in October 2008. It is an example of a small-size ice shelf that is a large melt water producer.

Environmental controls on micro fracture processes in shelf ice

NASA Astrophysics Data System (ADS)

Sammonds, Peter

2013-04-01

The recent retreat and collapse of the ice shelves on the Antarctic Peninsula has been associated with regional atmospheric warming, oceanic warming, increased summer melt and shelf flexure. Although the cause of collapse is a matter of active discussion, the process is that of fracture of a creep-brittle material, close to its melting point. The environmental controls on how fracturing initiates, at a micro-scale, strongly determine the macroscopic disintegration of ice shelves. In particular the shelf temperature profile controls the plasticity of the ice shelf; the densification of shelf ice due to melting and re-freezing affects the crack tip stress intensity; the accretion of marine ice at the bottom of the shelf imposes a thermal/mechanical discontinuity; saline environments control crack tip stress corrosion; cyclic loading promotes sub-critical crack propagation. These strong environmental controls on shelf ice fracture means that assessing shelf stability is a non-deterministic problem. How these factors may be parameterized in ice shelf models, through the use of fracture mechanisms maps, is discussed. The findings are discussed in relation to the stability of Larsen C.

Wave climate model of the Mid-Atlantic shelf and shoreline (Virginian Sea): Model development, shelf geomorphology, and preliminary results

NASA Technical Reports Server (NTRS)

Goldsmith, V.; Morris, W. D.; Byrne, R. J.; Whitlock, C. H.

1974-01-01

A computerized wave climate model is developed that applies linear wave theory and shelf depth information to predict wave behavior as they pass over the continental shelf as well as the resulting wave energy distributions along the coastline. Reviewed are also the geomorphology of the Mid-Atlantic Continental Shelf, wave computations resulting from 122 wave input conditions, and a preliminary analysis of these data.

Antarctic sub-shelf melt rates via PICO

NASA Astrophysics Data System (ADS)

Reese, Ronja; Albrecht, Torsten; Mengel, Matthias; Asay-Davis, Xylar; Winkelmann, Ricarda

2018-06-01

Ocean-induced melting below ice shelves is one of the dominant drivers for mass loss from the Antarctic Ice Sheet at present. An appropriate representation of sub-shelf melt rates is therefore essential for model simulations of marine-based ice sheet evolution. Continental-scale ice sheet models often rely on simple melt-parameterizations, in particular for long-term simulations, when fully coupled ice-ocean interaction becomes computationally too expensive. Such parameterizations can account for the influence of the local depth of the ice-shelf draft or its slope on melting. However, they do not capture the effect of ocean circulation underneath the ice shelf. Here we present the Potsdam Ice-shelf Cavity mOdel (PICO), which simulates the vertical overturning circulation in ice-shelf cavities and thus enables the computation of sub-shelf melt rates consistent with this circulation. PICO is based on an ocean box model that coarsely resolves ice shelf cavities and uses a boundary layer melt formulation. We implement it as a module of the Parallel Ice Sheet Model (PISM) and evaluate its performance under present-day conditions of the Southern Ocean. We identify a set of parameters that yield two-dimensional melt rate fields that qualitatively reproduce the typical pattern of comparably high melting near the grounding line and lower melting or refreezing towards the calving front. PICO captures the wide range of melt rates observed for Antarctic ice shelves, with an average of about 0.1 m a-1 for cold sub-shelf cavities, for example, underneath Ross or Ronne ice shelves, to 16 m a-1 for warm cavities such as in the Amundsen Sea region. This makes PICO a computationally feasible and more physical alternative to melt parameterizations purely based on ice draft geometry.

Building up knowledge on resilience of fragile lands in subarctic climate - a metadatabase for land degradation and restoration in southern Iceland

NASA Astrophysics Data System (ADS)

Finger, David C.; de Lavenne, Alban; Þórsson, Jóhann

2016-04-01

Resilience is the capacity of an ecosystem to respond to a perturbation or disturbance by resisting perturbations and recovering quickly. Natural catastrophes, such as floods, droughts, landslides, storms and volcanic eruptions can have devastating impacts on natural and build environment. Nevertheless, researchers worldwide have identified anthropogenic impacts to be the cause for enhanced consequences of natural catastrophes. Iceland, the small island on the mid Atlantic ridge is an ideal location to investigate anthropogenic impacts on the resilience of natural ecosystems. The dramatic deforestation after the arrival of the first settlers ~1100 years ago, the subsequent year round livestock grazing along with devastating ash emissions during volcanic eruptions and a harsh sub-polar oceanic climate have led to severe degradation of large areas of Icelandic soils. Since the beginning of the 20th century diverse restoration measures have been implemented at a large-scale on lowland areas of Iceland making them an ideal case study to investigate the effects of restoration on the resilience of water resources. Since over 100 years the Soil Conservation Service of Iceland (SCSI) has been restoring and investigating degraded landscapes, collecting valuable information and data on restoration research in Iceland. In a joint effort to provide an overview of terminated and ongoing research project, the SCSI and Reykjavik University have established a metadatabase summarizing all relevant restoration projects in the Rangárvellir area, a representative study site in southern Iceland. The SCSI and other governmental agencies have conducted numerous research and restoration projects in the area, including land restoration, land management, reforestation, hydrometeorological monitoring, vegetation mapping, to name just a few. The combination of these projects provides a valuable set of observational data and knowledge regarding the history of land restoration in Rang

An Icelandic Heritage: The Frame for One Teacher's Service (1946-2006)

ERIC Educational Resources Information Center

Crippen, Carolyn

2015-01-01

This qualitative research manuscript details a biographical study, which documents the life story of one female teacher, Sylvia May Peiluck, of Gimli, Manitoba, an educator of 45 years. Her Icelandic heritage and her commitment to teach the children of Manitoba created a strong bond, a nexus. What educational changes did she witness during her…

Coupled ocean-shelf ecosystem modelling of northern North Atlantic

NASA Astrophysics Data System (ADS)

Harle, J.; Holt, J. T.; Butenschön, M.; Allen, J. I.

2016-02-01

The biogeochemistry and ecosystems of the open-ocean and shelf seas are intimately connected. For example Northwest European continental shelf receives a substantial fraction of its nutrients from the wider North Atlantic and exports carbon at depth, sequestering it from atmospheric exchange. In the EC FP7 EuroBasin project (Holt et al 2014) we have developed a 1/12 degree basin-scale NEMO-ERSEM model with specific features relevant to shelf seas (e.g. tides and advanced vertical mixing schemes). This model is eddy resolving in the open-ocean, and resolves barotropic scales on-shelf. We use this model to explore the interaction between finely resolved physical processes and the ecosystem. Here we focus on shelf-sea processes and the connection between the shelf seas and open-ocean, and compare results with a 1/4 degree (eddy permitting) model that does not include shelf sea processes. We find tidal mixing fronts and river plume are well represented in the 1/12 degree model. Using approaches developed for the NW Shelf (Holt et al 2012), we provide estimates of across-shelf break nutrient fluxes to the seas surrounding this basin, and relate these fluxes and their interannual variability to the physical processes driving ocean-shelf exchange. Holt, J., et al, 2012. Oceanic controls on the primary production of the northwest European continental shelf: model experiments under recent past conditions and a potential future scenario. Biogeosciences 9, 97-117. Holt, J., et al, 2014. Challenges in integrative approaches to modelling the marine ecosystems of the North Atlantic: Physics to Fish and Coasts to Ocean. Progress in Oceanography doi:10.1016/j.pocean.2014.04.024.

Ash plume from Eyjafjallajokull Volcano, Iceland May 8th View

NASA Image and Video Library

2017-12-08

NASA image acquired May 8, 2010 at 13 :35 UTC Ash plume from Eyjafjallajokull Volcano, Iceland Satellite: Aqua NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Vacuum Drying for Extending Litchi Shelf-Life: Vitamin C, Total Phenolics, Texture and Shelf-Life Assessment.

PubMed

Richter Reis, Felipe; de Oliveira, Aline Caroline; Gadelha, Gabriella Giani Pieretti; de Abreu, Marcela Breves; Soares, Hillary Isabelle

2017-06-01

In an attempt to obtain shelf-stable litchi fruit with preserved nutritional quality and good sensory features, quarters of peeled and pitted fruits were vacuum dried at 50, 60 and 70 °C at a constant pressure of 8.0 kPa. The product was assessed for its vitamin C, total phenolics and texture (hardness). In addition, the product with the best texture was assessed for its shelf-life by means of accelerated testing. Results suggest that vacuum dried litchi retained almost 70% of the vitamin C and total phenolics when compared to frozen fruits (control). Vitamin C and phenolic compounds content significantly decreased with drying, while no difference was found between different drying temperatures. Hardness increased with drying temperature. The sample dried at 70 °C presented crispness, which is a desired quality feature in dried fruit products. This sample was subjected to shelf-life evaluation, whose result suggests a shelf-life of eight months at 23 °C. Total color change (CIE ΔE 00 ) was the expiry criterion. Vacuum drying was a suitable technique for producing shelf-stable litchi fruit with good texture while preserving its desirable original nutrients. Consumption of vacuum dried litchi may be beneficial to health due to its remarkable content of phenolic compounds and vitamin C.

Continuous deflation and plate spreading at the Askja volcanic system, Iceland: Constrains on deformation processes from finite element models using temperature-dependent non-linear rheology

NASA Astrophysics Data System (ADS)

Tariqul Islam, Md.; Sturkell, Erik; Sigmundsson, Freysteinn; Drouin, Vincent Jean Paul B.; Ófeigsson, Benedikt G.

2014-05-01

Iceland is located on the mid Atlantic ridge, where the spreading rate is nearly 2 cm/yr. The high rate of magmatism in Iceland is caused by the interaction between the Iceland hotspot and the divergent mid-Atlantic plate boundary. Iceland hosts about 35 volcanoes or volcanic systems that are active. Most of these are aliened along the plate boundary. The best studied magma chamber of central volcanoes (e.g., Askja, Krafla, Grimsvötn, Katla) have verified (suggested) a shallow magma chamber (< 5 km), which has been model successfully with a Mogi source, using elastic and/or elastic-viscoelastic half-space. Maxwell and Newtonian viscosity is mainly considered for viscoelastic half-space. Therefore, rheology may be oversimplified. Our attempt is to study deformation of the Askja volcano together with plate spreading in Iceland using temperature-dependent non-linear rheology. It offers continuous variation of rheology, laterally and vertically from rift axis and surface. To implement it, we consider thermo-mechanic coupling models where rheology follows dislocation flow in dry condition based on a temperature distribution. Continuous deflation of the Askja volcanic system is associated with solidification of magma in the magma chamber and post eruption relaxation. A long time series of levelling data show its subsidence trend to exponentially. In our preliminary models, a magma chamber at 2.8 km depth with 0.5 km radius is introduced at the ridge axis as a Mogi source. Simultaneously far field of rift axis stretching by 18.4 mm/yr (measured during 2007 to 20013) is applied to reproduce plate spreading. Predicted surface deformation caused of combined effect of tectonic-volcanic activities is evaluated with GPS during 2003-2009 and RADARSAT InSAR data during 2000 to 2010. During 2003-2009, data from the GPS site OLAF (close to the centre of subsidence) shows average rate of subsidence 19±1 mm/yr relative to the ITRF2005 reference frame. The MASK (Mid ASKJA) site is

Cretaceous shelf-sea chalk deposits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hattin, D.E.

1988-01-01

The word ''chalk'' is linked etymologically to the Cretaceous, but chalky facies neither dominate that system nor are confined to it. As used commonly, the term ''chalk'' refers to a variety of marine limestone that is white to light gray very fine grained, soft and friable, porous, and composed predominantly of calcitic skeletal remains, especially those derived from coccolithophores. No simple definition suffices to embrace all Cretaceous chalks, which include sandy, marly, shelly, phospatic, glauconitic, dolomitic, pyritic and organic-rich lithotypes. Most of the world's exposed Cretaceous chalk deposits were formed at shelf depths rather than in the deep sea. Cretaceousmore » shelf-sea chalks are developed most extensively in northern Europe, the U.S. Gulf Coastal Plain and Western Interior, and the Middle East, with lesser occurrences alo in Australia. Most Cretaceous shelf-sea chalks formed in the temperature zones, and in relatively deep water. Cretaceous chalks deposited on well-oxygenated sea floors are bioturbated and massive where deficient in terrigenous detritus, or bioturbated and rhythmically interbedded with argillaceous units where influx of terrigenous detritus varied systematically with climate changes. Accumulation of sufficient pelagic mud to form vast deposits of Cretaceous shelf-sea chalk required (1) sustained high productivity of calareous plankton, (2) extensive development of stable shelf and continental platform environments, (3) highstands of seal level, (4) deficiency of aragonitic skeletal material in chalk-forming sediments, and (5) low rates of terrigenous detrital influx. These conditions were met at different times in different places, even within the same general region.« less

Investigations of Very High Enthalpy Geothermal Resources in Iceland.

NASA Astrophysics Data System (ADS)

Elders, W. A.; Fridleifsson, G. O.

2012-12-01

The Iceland Deep Drilling Project (IDDP) is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. Earlier modeling indicates that the power output of a geothermal well producing from a supercritical reservoir could potentially be an order of magnitude greater than that from a conventional hot geothermal reservoir, at the same volumetric flow rate. However, even in areas with an unusually high geothermal gradient, for normal hydrostatic pressure gradients reaching supercritical temperatures and pressures will require drilling to depths >4 km. In 2009 the IDDP attempted to drill the first deep supercritical well, IDDP-01, in the caldera of the Krafla volcano, in NE Iceland. However drilling had to be terminated at only 2.1 km depth when ~900°C rhyolite magma flowed into the well. Our studies indicate that this magma formed by partial melting of hydrothermally altered basalts within the Krafla caldera. Although this well was too shallow to reach supercritical pressures, it is highly productive, and is estimated to be capable of generating up to 36 MWe from the high-pressure, superheated steam produced from the upper contact zone of the intrusion. With a well-head temperature of ~440°C, it is at present apparently the hottest producing geothermal well in the world. A pilot plant is investigating the optimal utilization of this magmatically heated resource. A special issue of the journal Geothermics with 16 papers reporting on the IDDP-01 is in preparation. However, in order to continue the search for supercritical geothermal resources, planning is underway to drill a 4.5 km deep well at Reykjanes in SW Iceland in 2013-14. Although drilling deeper towards the heat source of this already developed high-temperature geothermal field will be more expensive, if a supercritical resource is found, this cost increase should be offset by the considerable increase in the power output and lifetime of the Reykjanes geothermal

The Iceland Deep Drilling Project 4.5 km deep well, IDDP-2, in the seawater-recharged Reykjanes geothermal field in SW Iceland has successfully reached its supercritical target

NASA Astrophysics Data System (ADS)

Friðleifsson, Guðmundur Ó.; Elders, Wilfred A.; Zierenberg, Robert A.; Stefánsson, Ari; Fowler, Andrew P. G.; Weisenberger, Tobias B.; Harðarson, Björn S.; Mesfin, Kiflom G.

2017-11-01

The Iceland Deep Drilling Project research well RN-15/IDDP-2 at Reykjanes, Iceland, reached its target of supercritical conditions at a depth of 4.5 km in January 2017. After only 6 days of heating, the measured bottom hole temperature was 426 °C, and the fluid pressure was 34 MPa. The southern tip of the Reykjanes peninsula is the landward extension of the Mid-Atlantic Ridge in Iceland. Reykjanes is unique among Icelandic geothermal systems in that it is recharged by seawater, which has a critical point of 406 °C at 29.8 MPa. The geologic setting and fluid characteristics at Reykjanes provide a geochemical analog that allows us to investigate the roots of a mid-ocean ridge submarine black smoker hydrothermal system. Drilling began with deepening an existing 2.5 km deep vertical production well (RN-15) to 3 km depth, followed by inclined drilling directed towards the main upflow zone of the system, for a total slant depth of 4659 m ( ˜ 4.5 km vertical depth). Total circulation losses of drilling fluid were encountered below 2.5 km, which could not be cured using lost circulation blocking materials or multiple cement jobs. Accordingly, drilling continued to the total depth without return of drill cuttings. Thirteen spot coring attempts were made below 3 km depth. Rocks in the cores are basalts and dolerites with alteration ranging from upper greenschist facies to amphibolite facies, suggesting that formation temperatures at depth exceed 450 °C. High-permeability circulation-fluid loss zones (feed points or feed zones) were detected at multiple depth levels below 3 km depth to bottom. The largest circulation losses (most permeable zones) occurred between the bottom of the casing and 3.4 km depth. Permeable zones encountered below 3.4 km accepted less than 5 % of the injected water. Currently, the project is attempting soft stimulation to increase deep permeability. While it is too early to speculate on the energy potential of this well and its economics, the IDDP

Very large dune formation along the Ebro outer continental shelf (Western Mediterranean)

NASA Astrophysics Data System (ADS)

Lo Iacono, Claudio; Guillén, Jorge; Puig, Pere; Ribó, Marta; Ballesteros, Maria; Palanques, Albert; Farrán, Marcelli; Acosta, Juan

2010-05-01

Large and very large subaqueous dunes have been observed in a number of outer shelf regions around the world, tipically developing on fossil sand bodies and ridges. Dunes observed on outer shelves usually display large dimensions with maximum wavelength reaching up to 500 m and heights up to 20 m. Forcing mechanisms able to induce their formation have been described as strong bottom currents related to tidal variations and water masses flowing under geostrophic conditions, generally controlled and enhanced by local geomorphologic configurations. In this study, such bed features have been recognized, mapped and measured around the Columbretes Islands (Ebro continental shelf - Western Mediterranean) with the aim to reconstruct which are the potential forcing processes that could generate them in relation to the local settings of the area. Swath-bathymetry around the Columbretes Islands was collected using 30 kHz and 180 kHz Multi Beam echo-sounders for a 50-400 m water depth range. Bathymetric data revealed the presence of three main relict sand bodies along the outer shelf, for a 80-116 m depth range, above which asymmetrical, slightly asymmetrical and symmetrical large and very large 2D and 3D subaqueous dunes were observed. Dunes range from 150 to 760 m in wavelength and from tens of cm to 6 m in height. These bedforms are composed of sandy sediments, presumably coming from the degraded relict sand bodies on which they developed, mixed to the fine fractions coming from the recent draping holocenic sediments. The orientation of the dunes is SSW and progressively turns to W directions moving towards the southernmost sector of the area, following the trend of the shelf-edge. Observed dunes display a strong asymmetric profile for those occurring along the shelf-edge (Symmetry Index (SI): 2.6) and lose progressively their asymmetry towards the inner portion of the shelf (SI: 0.5), being 0.6 the minimum SI value to classify the dunes as asymmetric. The subaqueous dunes

Statistics of Stacked Strata on Experimental Shelf Margins

NASA Astrophysics Data System (ADS)

Fernandes, A. M.; Straub, K. M.

2015-12-01

Continental margin deposits provide the most complete record on Earth of paleo-landscapes, but these records are complex and difficult to interpret. To a seismic geomorphologist or stratigrapher, mapped surfaces often present a static diachronous record of these landscapes through time. We present data that capture the dynamics of experimental shelf-margin landscapes at high-temporal resolution and define internal hierarchies within stacked channelized and weakly channelized deposits from the shelf to the slope. Motivated by observations from acoustically-imaged continental margins offshore Brunei and in the Gulf of Mexico, we use physical experiments to quantify stratal patterns of sub-aqueous slope channels and lobes that are linked to delta-top channels. The data presented here are from an experiment that was run for 26 hours of experimental run time. Overhead photographs and topographic scans captured flow dynamics and surface aggradation/degradation every ten minutes. Currents rich in sediment built a delta that prograded to the shelf-edge. These currents were designed to plunge at the shoreline and travel as turbidity currents beyond the delta and onto the continental slope. Pseudo-subsidence was imposed by a slight base-level rise that generated accommodation space and promoted the construction of stratigraphy on the delta-top. Compensational stacking is a term that is frequently applied to deposits that tend to fill in topographic lows in channelized and weakly channelized systems. The compensation index, a metric used to quantify the strength of compensation, is used here to characterize deposits at different temporal scales on the experimental landscape. The compensation timescale is the characteristic time at which the accumulated deposits begins to match the shape of basin-wide subsidence rates (uniform for these experiments). We will use the compensation indices along strike transects across the delta, proximal slope and distal slope to evaluate the

Bathymetry and acoustic backscatter of the mid and outer continental shelf, head of De Soto Canyon, northeastern Gulf of Mexico

USGS Publications Warehouse

Gardner, James V.; Hughes-Clarke, John E.; Meyer, Larry A.

2002-01-01

The mid to outer continental shelf off Mississippi-Alabama and off northwest Florida were the focus of US Geological Survey (USGS) multibeam echosounder (MBES) mapping cruises in 2000 and 2001, respectively. These areas were mapped to investigate the extent of "deep-water reefs" first suggested by Ludwick and Walton (1957). The reefs off Mississippi and Alabama were initially described in water depths of 60 to 120 m (Ludwick and Walton, 1957) but the 2000 mapping found reef and hardgrounds to be much more extensive than previously thought (Gardner et al., 2001). The persistent trend of reef-like features along the outer shelf of Mississippi-Alabama suggested the trend might continue along the northwest Florida mid and outer shelf so a MBES-mapping effort was mounted in 2001 to test this suggestion. It is critical to determine the accurate location, geomorphology, and types of the ridges and reefs that occur in this region to understand the Quaternary history of the area and to assess their importance as benthic habitats for fisheries. The 2001 survey found a series of shelf-depth platforms with ridges (possibly reefs) constructed on their surfaces (Gardner et al., 2002). The area known as the "head of De Soto Canyon" is the large unmapped region between the 2000 and 2001 mapped areas. The head of De Soto Canyon is an outer shelf zone with a relatively steep western wall and a much gentler eastern wall. It was unknown prior to this cruise whether the reefs of the Mississippi-Alabama shelf continue eastward into the head of De Soto Canyon and connect with the ridges and reefs mapped on the northwest Florida outer shelf. The existence of carbonate-cemented latest Quaternary to Holocene sandstones along the western wall of the head of De Soto Canyon (Shipp and Hopkins, 1978; Benson et al., 1997; W.W. Schroeder, personnel comm., 2002) is of interest because of the potential benthic habitats they may represent. Precisely georeferenced high-resolution mapping of

Societal Influences on Children's Psychology: The Schools in Iceland and Singapore Promote Prosocial Values, Positive Self-Concepts, and Achievement in Young Adolescents

ERIC Educational Resources Information Center

Stiles, Deborah A.

2005-01-01

In most ways the island nations of Iceland and Singapore could not be more different from each other: Iceland is sparsely populated, located near the Arctic Circle, and a very free and individualistic democratic society; Singapore is densely populated, located near the equator, and a very regulated and collectivist meritocracy. But both nations…

Automating Trend Analysis for Spacecraft Constellations

NASA Technical Reports Server (NTRS)

Davis, George; Cooter, Miranda; Updike, Clark; Carey, Everett; Mackey, Jennifer; Rykowski, Timothy; Powers, Edward I. (Technical Monitor)

2001-01-01

missions such as DRACO with the intent that mission operations costs be significantly reduced. The goal of the Constellation Spacecraft Trend Analysis Toolkit (CSTAT) project is to serve as the pathfinder for a fully automated trending system to support spacecraft constellations. The development approach to be taken is evolutionary. In the first year of the project, the intent is to significantly advance the state of the art in current trending systems through improved functionality and increased automation. In the second year, the intent is to add an expert system shell, likely through the adaptation of an existing commercial-off-the-shelf (COTS) or government-off-the-shelf (GOTS) tool to implement some level of the trending intelligence that humans currently provide in manual operations. In the third year, the intent is to infuse the resulting technology into a near-term constellation or formation-flying mission to test it and gain experience in automated trending. The lessons learned from the real missions operations experience will then be used to improve the system, and to ultimately incorporate it into a fully autonomous, closed-loop mission operations system that is truly capable of supporting large constellations. In this paper, the process of automating trend analysis for spacecraft constellations will be addressed. First, the results of a survey on automation in spacecraft mission operations in general, and in trending systems in particular will be presented to provide an overview of the current state of the art. Next, a rule-based model for implementing intelligent spacecraft subsystem trending will be then presented, followed by a survey of existing COTS/GOTS tools that could be adapted for implementing such a model. The baseline design and architecture of the CSTAT system will be presented. Finally, some results obtained from initial software tests and demonstrations will be presented.

Nucleospora cyclopteri n. sp., an intranuclear microsporidian infecting wild lumpfish, Cyclopterus lumpus L., in Icelandic waters

PubMed Central

2013-01-01

Background Commercial fisheries of lumpfish Cyclopterus lumpus have been carried out in Iceland for centuries. Traditionally the most valuable part is the eggs which are harvested for use as a caviar substitute. Previously reported parasitic infections from lumpfish include an undescribed intranuclear microsporidian associated with abnormal kidneys and mortalities in captive lumpfish in Canada. During Icelandic lumpfish fisheries in spring 2011, extensive enlargements to the kidneys were observed in some fish during processing. The aim of this study was to identify the pathogen responsible for these abnormalities. Methods Lumpfish from the Icelandic coast were examined for the causative agent of kidney enlargement. Fish were dissected and used in histological and molecular studies. Results Lumpfish, with various grades of clinical signs, were observed at 12 of the 43 sites sampled around Iceland. From a total of 77 fish examined, 18 had clear clinical signs, the most prominent of which was an extensive enlargement and pallor of the kidneys. The histopathology of the most severely affected fish consisted of extensive degeneration and necrosis of kidney tubules and vacuolar degeneration of the haematopoietic tissue. Intranuclear microsporidians were detected in all organs examined in fish with prominent clinical signs and most organs of apparently healthy fish using the new PCR and histological examination. One or multiple uniformly oval shaped spores measuring 3.12 ± 0.15 × 1.30 ± 0.12 μm were observed in the nucleus of affected lymphocytes and lymphocyte precursor cells. DNA sequencing provided a ribosomal DNA sequence that was strongly supported in phylogenetic analyses in a clade containing other microsporidian parasites from the Enterocytozoonidae, showing highest similarity to the intranuclear microsporidian Nucleospora salmonis. Conclusions Intranuclear microsporidian infections are common in wild caught lumpfish from around the Icelandic

Ice shelf structure derived from dispersion curve analysis of ambient seismic noise, Ross Ice Shelf, Antarctica

NASA Astrophysics Data System (ADS)

Diez, A.; Bromirski, P. D.; Gerstoft, P.; Stephen, R. A.; Anthony, R. E.; Aster, R. C.; Cai, C.; Nyblade, A.; Wiens, D. A.

2016-05-01

An L-configured, three-component short period seismic array was deployed on the Ross Ice Shelf, Antarctica during November 2014. Polarization analysis of ambient noise data from these stations shows linearly polarized waves for frequency bands between 0.2 and 2 Hz. A spectral peak at about 1.6 Hz is interpreted as the resonance frequency of the water column and is used to estimate the water layer thickness below the ice shelf. The frequency band from 4 to 18 Hz is dominated by Rayleigh and Love waves propagating from the north that, based on daily temporal variations, we conclude were generated by field camp activity. Frequency-slowness plots were calculated using beamforming. Resulting Love and Rayleigh wave dispersion curves were inverted for the shear wave velocity profile within the firn and ice to ˜150 m depth. The derived density profile allows estimation of the pore close-off depth and the firn-air content thickness. Separate inversions of Rayleigh and Love wave dispersion curves give different shear wave velocity profiles within the firn. We attribute this difference to an effective anisotropy due to fine layering. The layered structure of firn, ice, water and the seafloor results in a characteristic dispersion curve below 7 Hz. Forward modelling the observed Rayleigh wave dispersion curves using representative firn, ice, water and sediment structures indicates that Rayleigh waves are observed when wavelengths are long enough to span the distance from the ice shelf surface to the seafloor. The forward modelling shows that analysis of seismic data from an ice shelf provides the possibility of resolving ice shelf thickness, water column thickness and the physical properties of the ice shelf and underlying seafloor using passive-source seismic data.

People with Intellectual Disabilities in Iceland: A Bourdieuean Interpretation of Self-Advocacy

ERIC Educational Resources Information Center

Bjornsdottir, Kristin; Johannesson, Ingolfur Asgeir

2009-01-01

There are many barriers to social participation in Iceland for people with intellectual disabilities. This article builds on qualitative research with young adults with intellectual disabilities. The purpose of this article is to develop an approach where the struggles over the meaning of social participation of people with intellectual…

Breakup of Pack Ice, Antarctic Ice Shelf

NASA Technical Reports Server (NTRS)

1991-01-01

Breakup of Pack Ice along the periphery of the Antarctic Ice Shelf (53.5S, 3.0E) produced this mosaic of ice floes off the Antarctic Ice Shelf. Strong offshore winds, probably associated with strong katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filamets of sea ice, icebergs, bergy bits and growlers to flow northward into the South Atlantic Ocean. 53.5S, 3.0E

[Prevalence and diversity of emotional abuse and neglect in childhood in Iceland].

PubMed

Einarsdottir, Jonina; Gunnlaugsson, Geir

2015-03-01

Parenting styles that include abuse can harm the development of the child's brain with a long or short-term impact on his/her health and behaviour. The scope and diversity of abuse are important determinants, and neglect is one of its most serious manifestations. The aim of the study is to examine the prevalence and diversity of emotional abuse and neglect reported by adult Icelanders in their childhood, and how such experience had influenced their evaluation of their upbringing. Icelanders 18 years and older were randomly selected from the national population register. They were invited to express their perception of their upbringing, and answer questions regarding their experience of 8 specific forms of emotional abuse in childhood, and neglect. Of 966 interviewees, 663 (69%) had experienced one or more of the 8 forms of emotional abuse. Those younger than 30 years were 2.9 times more likely to have such an experience compared to those who were older (95% CI 1.9 to 4.3). The perception of upbringing as bad or acceptable compared to good was significantly related to the number of forms of emotional abuse applied (p<0.0001) and the scope of its application (p<0.0001). In total 105 (11%) considered that they had experienced neglect in childhood. Significantly more men than women had experienced emotional abuse (p= 0.0020), whereas women reported neglect (p=0.0440). More than 2/3 of adult Icelanders report experience of one or more out of 8 different forms of emotional abuse and 1/10 report neglect. Parenting styles can be changed, e.g. with education, social support, and legislation.

The Rise and Fall of the Social Science Curriculum Project in Iceland, 1974-84: Reflections on Reason and Power in Educational Progress.

ERIC Educational Resources Information Center

Edelstein, Wolfgang

This description of the content and structure of a 10-year Icelandic Social Science Curriculum Project serves as a commentary on the role of the project in the context of Icelandic curriculum reform. A discussion of the place of structural developmental curricula in the reform dynamics of educational progressivism precede the specifics of the…

Shelf life of packaged bakery goods--a review.

PubMed

Galić, K; Curić, D; Gabrić, D

2009-05-01

Packaging requirements for fresh bakery goods are often minimal as many of the products are for immediate consumption. However, packaging can be an important factor in extending the shelf life of other cereal-based goods (toast, frozen products, biscuits, cakes, pastas). Some amount of the texture changes and flavor loss manifest over the shelf life of a soft-baked good can usually be minimized or delayed by effective use of packaging materials. The gains in the extension of shelf life will be application specific. It is recognized that defining the shelf life of a food is a difficult task and is an area of intense research for food product development scientists (food technologists, microbiologists, packaging experts). Proper application of chemical kinetic principles to food quality loss allows for efficiently designing appropriate shelf-life tests and maximizing the useful information that can be obtained from the resulting data. In the development of any new food product including reformulating, change of packaging, or storage/distribution condition (to penetrate into a new market), one important aspect is the knowledge of shelf life.

Sensory shelf life of dulce de leche.

PubMed

Garitta, L; Hough, G; Sánchez, R

2004-06-01

The objectives of this research were to determine the sensory cutoff points for dulce de leche (DL) critical descriptors, both for defective off-flavors and for storage changes in desirable attributes, and to estimate the shelf life of DL as a function of storage temperature. The critical descriptors used to determine the cutoff points were plastic flavor, burnt flavor, dark color, and spreadability. Linear correlations between sensory acceptability and trained panel scores were used to determine the sensory failure cutoff point for each descriptor. To estimate shelf life, DL samples were stored at 25, 37, and 45 degrees C. Plastic flavor was the first descriptor to reach its cutoff point at 25 degrees C and was used for shelf-life calculations. Plastic flavor vs. storage time followed zero-order reaction rate. Shelf-life estimations at different temperatures were 109 d at 25 degrees C, 53 d at 37 degrees C, and 9 d at 45 degrees C. The activation energy, necessary to calculate shelf lives at different temperatures, was 14,370 +/- 2080 cal/mol.

Seasonal cycle of circulation in the Antarctic Peninsula and the off-shelf transport of shelf waters into southern Drake Passage and Scotia Sea

NASA Astrophysics Data System (ADS)

Jiang, Mingshun; Charette, Matthew A.; Measures, Christopher I.; Zhu, Yiwu; Zhou, Meng

2013-06-01

The seasonal cycle of circulation and transport in the Antarctic Peninsula shelf region is investigated using a high-resolution (˜2 km) regional model based on the Regional Oceanic Modeling System (ROMS). The model also includes a naturally occurring tracer with a strong source over the shelf (radium isotope 228Ra, t1/2=5.8 years) to investigate the sediment Fe input and its transport. The model is spun-up for three years using climatological boundary and surface forcing and then run for the 2004-2006 period using realistic forcing. Model results suggest a persistent and coherent circulation system throughout the year consisting of several major components that converge water masses from various sources toward Elephant Island. These currents are largely in geostrophic balance, driven by surface winds, topographic steering, and large-scale forcing. Strong off-shelf transport of the Fe-rich shelf waters takes place over the northeastern shelf/slope of Elephant Island, driven by a combination of topographic steering, extension of shelf currents, and strong horizontal mixing between the ACC and shelf waters. These results are generally consistent with recent and historical observational studies. Both the shelf circulation and off-shelf transport show a significant seasonality, mainly due to the seasonal changes of surface winds and large-scale circulation. Modeled and observed distributions of 228Ra suggest that a majority of Fe-rich upper layer waters exported off-shelf around Elephant Island are carried by the shelfbreak current and the Bransfield Strait Current from the shallow sills between Gerlache Strait and Livingston Island, and northern shelf of the South Shetland Islands, where strong winter mixing supplies much of the sediment derived nutrients (including Fe) input to the surface layer.

Sub-ice-shelf sediments record history of twentieth-century retreat of Pine Island Glacier.

PubMed

Smith, J A; Andersen, T J; Shortt, M; Gaffney, A M; Truffer, M; Stanton, T P; Bindschadler, R; Dutrieux, P; Jenkins, A; Hillenbrand, C-D; Ehrmann, W; Corr, H F J; Farley, N; Crowhurst, S; Vaughan, D G

2017-01-05

The West Antarctic Ice Sheet is one of the largest potential sources of rising sea levels. Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line-which marks the boundary between grounded ice and floating ice shelf-is underway. Understanding this recent retreat requires a detailed knowledge of grounding-line history, but the locations of the grounding line before the advent of satellite monitoring in the 1990s are poorly dated. In particular, a history of grounding-line retreat is required to understand the relative roles of contemporaneous ocean-forced change and of ongoing glacier response to an earlier perturbation in driving ice-sheet loss. Here we show that the present thinning and retreat of Pine Island Glacier in West Antarctica is part of a climatically forced trend that was triggered in the 1940s. Our conclusions arise from analysis of sediment cores recovered beneath the floating Pine Island Glacier ice shelf, and constrain the date at which the grounding line retreated from a prominent seafloor ridge. We find that incursion of marine water beyond the crest of this ridge, forming an ocean cavity beneath the ice shelf, occurred in 1945 (±12 years); final ungrounding of the ice shelf from the ridge occurred in 1970 (±4 years). The initial opening of this ocean cavity followed a period of strong warming of West Antarctica, associated with El Niño activity. Thus our results suggest that, even when climate forcing weakened, ice-sheet retreat continued.

Wintertime re-ventilation of the East Greenland Current's Atlantic-origin Overflow Water in the western Iceland Sea

NASA Astrophysics Data System (ADS)

Våge, Kjetil; Håvik, Lisbeth; Papritz, Lukas; Spall, Michael; Moore, Kent

2017-04-01

The Deep Western Boundary Current constitutes the lower limb of the Atlantic Meridional Overturning Circulation, and, as such, is a crucial component of the Earth's climate system. The largest and densest contribution to the current stems from the overflow plume that passes through Denmark Strait. A main source of Denmark Strait Overflow Water (DSOW) is the East Greenland Current (EGC). The DSOW transported by the EGC originates from the Atlantic inflow into the Nordic Seas. This is then transformed into Atlantic-origin Overflow Water while progressing northward through the eastern part of the Nordic Seas. Here we show, using measurements from autonomous gliders deployed from fall 2015 to spring 2016, that the Atlantic-origin Overflow Water transported toward Denmark Strait by the EGC was re-ventilated while transiting the western Iceland Sea in winter. In summer, this region is characterized by an upper layer of cold, fresh Polar Surface Water that is thought to prevent convection. But in fall and winter this fresh water mass is diverted toward the Greenland shelf by enhanced northerly winds, which results in a water column that is preconditioned for convection. Severe heat loss from the ocean to the atmosphere offshore of the ice edge subsequently causes the formation of deep mixed layers. This further transforms the Atlantic-origin Overflow Water and impacts the properties of the DSOW, and hence the deepest and densest component of the lower limb of the Atlantic Meridional Overturning Circulation.

Ice shelf structure from dispersion curve analysis of passive-source seismic data, Ross Ice Shelf, Antarctica

NASA Astrophysics Data System (ADS)

Diez, A.; Bromirski, P. D.; Gerstoft, P.; Stephen, R. A.; Anthony, R. E.; Aster, R. C.; Cai, C.; Nyblade, A.; Wiens, D.

2015-12-01

An L-shaped array of three-component short period seismic stations was deployed at the Ross Ice Shelf, Antarctica approximately 100 km south of the ice edge, near 180° longitude, from November 18 through 28, 2014. Polarization analysis of data from these stations clearly shows propagating waves from below the ice shelf for frequencies below 2 Hz. Energy above 2 Hz is dominated by Rayleigh and Love waves propagating from the north. Frequency-slowness plots were calculated using beamforming. Resulting Love and Rayleigh wave dispersion curves were inverted for the shear wave velocity profile, from which we derive a density profile. The derived shear wave velocity profiles differ within the firn for the inversions using Rayleigh and Love wave dispersion curves. This difference is attributed to an effective anisotropy due to fine layering. The layered structure of firn, ice, water, and ocean floor results in a characteristic dispersion curve pattern below 7 Hz. We investigate the observed structures in more detail by forward modeling of Rayleigh wave dispersion curves for representative firn, ice, water, sediment structures. Rayleigh waves are observed when wavelengths are long enough to span the distance from the ice shelf surface to the seafloor. Our results show that the analysis of high frequency Rayleigh waves on an ice shelf has the ability to resolve ice shelf thickness, water column thickness, and the physical properties of the underlying ocean floor using passive-source seismic data.

The May 29 2008 earthquake aftershock sequence within the South Iceland Seismic Zone: Fault locations and source parameters of aftershocks

NASA Astrophysics Data System (ADS)

Brandsdottir, B.; Parsons, M.; White, R. S.; Gudmundsson, O.; Drew, J.

2010-12-01

The mid-Atlantic plate boundary breaks up into a series of segments across Iceland. The South Iceland Seismic Zone (SISZ) is a complex transform zone where left-lateral E-W shear between the Reykjanes Peninsula Rift Zone and the Eastern Volcanic Zone is accommodated by bookshelf faulting along N-S lateral strike-slip faults. The SISZ is also a transient feature, migrating sideways in response to the southward propagation of the Eastern Volcanic Zone. Sequences of large earthquakes (M > 6) lasting from days to years and affecting most of the seismic zone have occurred repeatedly in historical time (last 1100 years), separated by intervals of relative quiescence lasting decades to more than a century. On May 29 2008, a Mw 6.1 earthquake struck the western part of the South Iceland Seismic Zone, followed within seconds by a slightly smaller event on a second fault ~5 km further west. Aftershocks, detected by a temporal array of 11 seismometers and three permanent Icelandic Meteorological Office stations were located using an automated Coalescence Microseismic Mapping technique. The epicenters delineate two major and several smaller N-S faults as well as an E-W zone of activity stretching further west into the Reykjanes Peninsula Rift Zone. Fault plane solutions show both right lateral and oblique strike slip mechanisms along the two major N-S faults. The aftershocks deepen from 3-5 km in the north to 8-9 km in the south, suggesting that the main faults dip southwards. The faulting is interpreted to be driven by the local stress due to transform motion between two parallel segments of the divergent plate boundary crossing Iceland.

An overview of the Icelandic Volcano Observatory response to the on-going rifting event at Bárðarbunga (Iceland) and the SO2 emergency associated with the gas-rich eruption in Holuhraun

NASA Astrophysics Data System (ADS)

Barsotti, Sara; Jonsdottir, Kristin; Roberts, Matthew J.; Pfeffer, Melissa A.; Ófeigsson, Benedikt G.; Vögfjord, Kristin; Stefánsdóttir, Gerður; Jónasdóttir, Elin B.

2015-04-01

On 16 August, 2014, Bárðarbunga volcano entered a new phase of unrest. Elevated seismicity in the area with up to thousands of earthquakes detected per day and significant deformation was observed around the Bárðarbunga caldera. A dike intrusion was monitored for almost two weeks until a small, short-lived effusive eruption began on 29 August in Holuhraun. Two days later a second, more intense, tremendously gas-rich eruption started that is still (as of writing) ongoing. The Icelandic Volcano Observatory (IVO), within the Icelandic Meteorological Office (IMO), monitors all the volcanoes in Iceland. Responsibilities include evaluating their related hazards, issuing warnings to the public and Civil Protection, and providing information regarding risks to aviation, including a weekly summary of volcanic activity provided to the Volcanic Ash Advisory Center in London. IVO has monitored the Bárðarbunga unrest phase since its beginning with the support of international colleagues and, in collaboration with the University of Iceland and the Environment Agency of Iceland, provides scientific support and interpretation of the ongoing phenomena to the local Civil Protection. The Aviation Color Code, for preventing hazards to aviation due to ash-cloud encounter, has been widely used and changed as soon as new observations and geophysical data from the monitoring network have suggested a potential evolution in the volcanic crisis. Since the onset of the eruption, IVO is monitoring the gas emission by using different and complementary instrumentations aimed at analyzing the plume composition as well as estimating the gaseous fluxes. SO2 rates have been measured with both real-time scanning DOASes and occasional mobile DOAS traveses, near the eruption site and in the far field. During the first month-and-a-half of the eruption, an average flux equal to 400 kg/s was registered, with peaks exceeding 1,000 kg/s. Along with these measurements the dispersal model CALPUFF has

Respiratory health effects of volcanic ash with special reference to Iceland. A review.

PubMed

Gudmundsson, Gunnar

2011-01-01

Volcano eruptions occur around the world and can have an impact on health in many ways both locally and on a global scale as a result of airborne dispersion of gases and ash or as impact on climate. In this review, a recent volcanic eruption in Eyjafjallajökull in Iceland is described and its effects on aviation around the globe and on respiratory health in those exposed to the volcanic ash in Iceland. Also, the effects of a large volcano eruption in Iceland in 1789 are described that also had effect on a global scale by causing air pollution. The available studies reviewed here suggest that the acute and chronic health effects of volcanic ash depend on particle size (how much respirable), mineralogical composition (crystalline silica content) and the physico-chemical properties of the surfaces of ash particles. These can vary between volcanoes and even between eruptions, making comparison difficult. Acute respiratory symptoms suggesting asthma and bronchitis have been well described. Exacerbations of pre-existing lung and heart disease are common after inhalation of volcanic ash. Limited information is available on increase in mortality from recent eruptions but historical evidence is well described. No long-term effects on lung function have been found after exposure to volcanic ash. There are concerns for the long-term risks of silicosis from chronic exposure to volcanic ash but no cases have been described. Acute respiratory symptoms after exposure to volcanic ash are well described but no long-term effects have been found. © 2010 Blackwell Publishing Ltd.

A long term glider study of shelf sea oxygen dynamics

NASA Astrophysics Data System (ADS)

Williams, Charlotte; Palmer, Matthew; Mahaffey, Claire; Davis, Clare

2017-04-01

Oxygen is involved in most biogeochemical processes in the ocean, and dissolved oxygen (DO) is a well-established indicator for biological activity via the estimate of apparent oxygen utilisation (AOU). In the deep waters of the open ocean, the AOU provides a valuable insight into the ocean's biological carbon pump. However, in the physically dynamic and highly productive shallow shelf seas, interpretation of the oxygen distribution and the magnitude of AOU is complex. Physical processes, such as diapycnal mixing, entrainment and horizontal advection act to ventilate waters below the thermocline and thus increase oxygen and decrease AOU. In contrast, biological remineralisation of organic material below the thermocline will consume oxygen and increase AOU. We aim to address the following: 1. Does AOU change seasonally in a shelf sea in response to seasonal changes in productivity? 2. How important is turbulence in redistributing oxygen in a shelf sea? Using 9 months of high-resolution data from >20 glider deployments in the seasonally stratified NW European Shelf Sea we identify and quantify the physical and biological processes that control the DO distribution and magnitude of AOU in shelf seas. A 200km transect between the shelf edge and the central Celtic Sea (CCS) was repeated between November 2014 and August 2015, thus capturing key periods in the seasonal cycling in shelf seas, specifically the onset of stratification, the spring bloom, stratified summer period and breakdown of stratification. The gliders collected data for DO, temperature, salinity, chlorophyll fluorescence, CDOM, backscatter and turbulence. In addition, direct measurements of turbulent dissipation from the Ocean Microstructure Glider deployed during the campaign provided estimates of mixing at CCS and the shelf break, allowing accurate quantification of the vertical fluxes of oxygen. We find that oxygen decreases ubiquitously across the shelf as soon as stratification takes hold, though BML

The Historical Development of Basic Color Terms in Old Norse-Icelandic

ERIC Educational Resources Information Center

Crawford, Jackson

2014-01-01

This dissertation discusses the color terms of the Old Norse-Icelandic (or Old West Norse) language and seeks to establish which color terms in that language are basic (i.e., not further reducible, as English scarlet is to red), and what the fields of reference of these color terms are. By establishing how the color spectrum is divided in Old West…

The radiogenic and stable Sr isotope geochemistry of basalt weathering in Iceland: Role of hydrothermal calcite and implications for long-term climate regulation

NASA Astrophysics Data System (ADS)

Andrews, M. Grace; Jacobson, Andrew D.

2017-10-01

Several studies have examined the geochemistry of Icelandic rivers to quantify the relationship between basalt weathering and long-term climate regulation. Recent research has suggested that the chemical weathering of hydrothermal and metamorphic calcite contributes significant quantities of HCO3- to the Icelandic riverine flux (Jacobson et al., 2015). Because the HCO3- derives from volcanic CO2 that was sequestered in mineral form prior to atmospheric injection, the strength of the basalt weathering feedback occurring in Iceland may be lower than previously realized. To test these hypotheses, we analyzed the radiogenic and stable Sr isotope composition (87Sr/86Sr and δ88/86Sr) of the same suite of water, rock, and mineral samples as examined in Jacobson et al. (2015), and we developed a simple model of the long-term C cycle that considers the transformation of volcanic CO2 to HCO3- during subsurface silicate weathering, which is a precursor to hydrothermal calcite formation. Interpretations based on 87Sr/86Sr and Ca/Sr ratios suggest that conservative, three-component mixing between basalt, calcite, and atmospheric deposition adequately explains river geochemistry. On average, the δ88/86Sr values of glacial and non-glacial rivers (0.414‰ and 0.388‰, respectively) are generally higher than those for basalt (0.276‰); however, calcite δ88/86Sr values (0.347‰) are also higher than those for basalt and span the range of riverine values. Thus, riverine δ88/86Sr values are also consistent three-component mixing between basalt, calcite, and atmospheric deposition. Isotopic fractionation is not required to explain riverine trends. Finally, model equations for the long-term C cycle demonstrate that subsurface silicate weathering reduces the magnitude of the volcanic CO2 degassing flux, which in turn causes the atmosphere to stabilize at lower pCO2 values compared to the case where no subsurface silicate weathering occurs. However, the proportion of the net

Food appearances in children's television programmes in Iceland.

PubMed

Olafsdottir, Steingerdur; Berg, Christina

2017-11-01

Exposure to advertisements cannot fully explain the associations between young children's dietary intake and the time they spend in front of the television. It is therefore of importance to study television content other than advertisements in this aspect. The present study aimed to examine the nature and extent of verbal and visual appearances of foods and beverages in children's television programmes on Icelandic public service television. A total of 27 h of children's programmes (domestic and internationally produced) were watched. All verbal and visual appearances of foods and beverages were coded, as well as the context in which the foods/beverages were discussed or appeared. Children's programmes on Icelandic public service television. Two food groups were of special interest for their importance from a public health perspective: high-calorie and low-nutrient (HCLN) foods and fruits and vegetables (F&V). The χ 2 test and logistic regression were performed to analyse if the occurrence of the two groups was associated with the context where foods/beverages appeared. Of the 125 different programmes, a food or beverage appeared in 86 %. Of the total food appearances (n 599), HCLN foods accounted for 26 % and F&V for 23 %. HCLN foods were presented as desirable by appearing more frequently with child characters (P<0·01) than F&V. Public service television has the potential to improve the way food and eating is presented in children's programmes, as young childhood is a critical period for founding healthy habits for later life.

PFAAs in Fish and Other Seafood Products from Icelandic Waters

PubMed Central

Halldorsson, Thorhallur I.; Gunnlaugsdottir, Helga

2014-01-01

Perfluorinatedalkyl acids (PFAAs) are of growing concern due to possible health effects on humans. Exposure assessments indicate that fish consumption is one of the major sources of perfluorooctane sulfonate (PFOS) exposure to humans, one of the major PFASs, whereas concerns of overestimation of this exposure source have been raised. Therefore, PFAAs concentrations in fish from the North Atlantic (Icelandic fishing grounds) in the flesh of different fish species were investigated along with more detailed analyses of tissue concentrations in cod (Gadus morhua) and lumpfish (Cyclopterus lumpus). Further, fish feed was investigated as a possible source of PFAAs in aquaculture by examining fish meal as feed ingredient. No PFAAs were detected in the edible part of all fish samples, except for PFOS in pollock (Pollachius virens, 0,05 ng/g wet weight). PFOS was the only PFAA detected in the fish meal samples with the exception of PFOSA in blue whiting (Micromesistius poutassou) meal (0,45 ng/g dry weight (d.w.)), where the PFOS concentration was 1,3–13 ng/g d.w. in the capelin (Mallotus villosus) and mackerel (Scomber scombrus) meal samples. The conclusions of the study are that fish commonly consumed from the Icelandic fishing grounds are unlikely to be an important source of PFAAs exposure. PMID:24782899

Long term trending of engineering data for the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Cox, Ross M.

1993-01-01

A major goal in spacecraft engineering analysis is the detection of component failures before the fact. Trending is the process of monitoring subsystem states to discern unusual behaviors. This involves reducing vast amounts of data about a component or subsystem into a form that helps humans discern underlying patterns and correlations. A long term trending system has been developed for the Hubble Space Telescope. Besides processing the data for 988 distinct telemetry measurements each day, it produces plots of 477 important parameters for the entire 24 hours. Daily updates to the trend files also produce 339 thirty day trend plots each month. The total system combines command procedures to control the execution of the C-based data processing program, user-written FORTRAN routines, and commercial off-the-shelf plotting software. This paper includes a discussion the performance of the trending system and of its limitations.

Professional Role and Identity of Icelandic Preschool Teachers: Effects of Stakeholders' Views

ERIC Educational Resources Information Center

Jónsdóttir, Arna H.; Coleman, Marianne

2014-01-01

In this article, we explore the reality of Icelandic preschool teachers who are, as in most other countries, predominantly female. The gendered nature of the role and the current identity adopted by preschool teachers appear to impact on their perceived status and professionalism. In this process, stakeholders in early childhood education (ECE),…

Dynamics of internal waves on the Southeast Florida shelf: Implications for cross-shelf exchange and turbulent mixing on a barrier reef system

NASA Astrophysics Data System (ADS)

Davis, Kristen Alexis

The dynamics of internal waves shoaling on the Southeast Florida shelf and the resulting stratified turbulence in the shelf bottom boundary layer are investigated using observational studies completed during the summers of 2003-2005. This work is driven by a desire to understand the effects of internal wave-driven flow and the shoreward transport of cool, nutrient-rich water masses on cross-shelf exchange, vertical mixing, and mass transfer to benthic reef organisms. Shelf sea internal wave fields are typically highly variable and dominated by wind and tidal forces. However, this is not necessarily true for outer shelf regions or very narrow shelves where remote physical processes originating over the slope or deep ocean may exert a strong influence on the internal wave climate. During the summers of 2003 and 2004 observational studies were conducted to examine the effects of a western boundary current (the Florida Current), tides, and wind on the mean currents and internal wave field on the outer Southeast Florida shelf. We present evidence that suggests that the Florida Current plays as large a role in the determination of the high frequency internal wave field as tidal forces. These observations and analyses show that it is necessary to include the forcing from the Florida Current meanders and instabilities in order to predict accurately the episodic nature of the internal wave field on the Southeast Florida shelf. Deep ocean and continental shelf processes intersect at the shelf edge and influence the exchange of water masses and their associated characteristics including heat, nutrients, sediment, and larvae across the shelf. Thus, the dynamics of cross-shelf circulation have important consequences for organisms living on the shelf. In the second phase of this work, we investigate physical mechanisms controlling the exchange of water masses during the summer season across the Southeast Florida shelf. A time series of cross-shelf transport from May to August

Basal crevasses and suture zones in the Larsen C Ice Shelf, Antarctica: Implications for ice shelf stability in a warming climate

NASA Astrophysics Data System (ADS)

McGrath, Daniel J.

Understanding ice shelf structure and processes is paramount to future predictions of sea level rise, as nearly 75% of the ice flux from the Antarctic Ice Sheet (AIS) passes through these gates. The breakup of an ice shelf removes the longitudinal back stress acting on the grounded inland ice and leads to flow acceleration, dynamic thinning and frontal retreat, processes that can be sustained for more than a decade. Increased ice discharge to the ocean contributes to global sea level rise. This dissertation investigates basal crevasses and suture zones, two key structural components of ice shelves, in order to understand how the structure of an ice shelf influences its stability in a warming climate. Ground penetrating radar, high-resolution satellite imagery and a variety of modeling approaches are utilized to assess these features on the Larsen C Ice Shelf but in a manner that considers their influence on ice shelf stability around the AIS. Basal crevasses are large-scale (~66% of ice thickness and ten's of kms in length) and abundant features that are significant structural weaknesses. The viscoplastic deformation of the ice shelf in response to the perturbed hydrostatic balance leads to the formation of both surface depressions and crevasses, hence weakening the ice shelf further. Basal crevasses increase the local ice-ocean interface by ~30%, thereby increasing basal roughness and altering ice-ocean interactions. Ice-shelf fractures frequently terminate where they encounter suture zones, regions of material heterogeneity that form at the lateral bounds of meteoric inflows to ice shelves. The termination of a 25 km-long rift in the Churchill Peninsula suture zone is investigated and found to contain ~60 m of accreted marine ice. Steady-state basal melting/freezing rates are determined for the ice shelf and applied to a flowline model to examine the along-flow evolution of ice shelf structure. The thickening surface wedge of locally accumulated meteoric ice

Endmembers of Ice Shelf Melt

NASA Astrophysics Data System (ADS)

Boghosian, A.; Child, S. F.; Kingslake, J.; Tedesco, M.; Bell, R. E.; Alexandrov, O.; McMichael, S.

2017-12-01

Studies of surface melt on ice shelves have defined a spectrum of meltwater behavior. On one end the storage of meltwater in persistent surface ponds can trigger ice shelf collapse as in the 2002 event leading to the disintegration of the Larsen B Ice Shelf. On the other, meltwater export by rivers can stabilize an ice shelf as was recently shown on the Nansen Ice Shelf. We explore this dichotomy by quantifying the partitioning between stored and transported water on two glaciers adjacent to floating ice shelves, Nimrod (Antarctica) and Peterman (Greenland). We analyze optical satellite imagery (LANDSAT, WorldView), airborne imagery (Operation IceBridge, Trimetrogon Aerial Phototography), satellite radar (Sentinel-1), and digital elevation models (DEMs) to categorize surface meltwater fate and map the evolution of ice shelf hydrology and topographic features through time. On the floating Peterman Glacier tongue a sizable river exports water to the ocean. The surface hydrology of Nimrod Glacier, geometrically similar to Peterman but with ten times shallower surface slope, is dominated by storage in surface lakes. In contrast, the Nansen has the same surface slope as Nimrod but transports water through surface rivers. Slope alone is not the sole control on ice shelf hydrology. It is essential to track the storage and transport volumes for each of these systems. To estimate water storage and transport we analyze high resolution (40 cm - 2 m) modern and historical DEMs. We produce historical (1957 onwards) DEMs with structure-from-motion photogrammetry. The DEMs are used to constrain water storage potential estimates of observed basins and water routing/transport potential. We quantify the total volume of water stored seasonally and interannually. We use the normalize difference water index to map meltwater extent, and estimate lake water depth from optical data. We also consider the role of stored water in subsurface aquifers in recharging surface water after

Seismic reflection and vibracoring studies of the continental shelf offshore central and western Long Island, New York

USGS Publications Warehouse

Kelly, W.M.; Albanese, J.R.; Coch, N.K.; Harsch, A.A.

1999-01-01

The ridge-and-swale topography on the continental shelf south of Fire Island, New York, is characterized by northeast-trending linear shoals that are shore attached and shore oblique on the inner shelf and isolated and shore parallel on the middle shelf. High-resolution seismic reflection profiles show that the ridges and swales occur independent of, and are not controlled by, the presence of internal structures (for example, filled tidal inlet channels, paleobarrier strata) or underlying structure (for example, high-relief Cretaceous unconformity). Grab samples of surficial sediments on the shelf south of Fire Island average 98% sand. Locally, benthic fauna increase silt and clay content through fecal pellet production or increase the content of gravel-size material by contribution of their fragmented shell remains. Surficial sand on the ridges is unimodal at 0.33 mm (medium sand, about 50 mesh), and surficial sand in troughs is bimodal at 0.33 mm and 0.15 mm (fine sand, about 100 mesh). In addition to seismic studies, 26 vibracores were recovered from the continental shelf in state and federal waters from south of Rockaway and Long Beaches, Long Island, New York. Stratigraphic and sedimentological data gleaned from these cores were used to outline the geologic framework in the study area. A variety of sedimentary features were noted in the cores, including burrow-mottled sections of sand in a finer silty-sand, rhythmic lamination of sand and silty-sand that reflect cyclic changes in sediment transport, layers of shell hash and shells that probably represent tempestites, and changes from dark color to light color in the sediments that probably represent changes in the oxidation-reduction conditions in the area with time. The stratigraphic units identified are an upper, generally oxidized, nearshore facies, an underlying fine- to medium-sand and silty-clay unit considered to be an estuarine facies, and a lower, coarse-grained deeply oxidized, cross-laminated pre

Arctic intermediate water in the Norwegian sea

NASA Astrophysics Data System (ADS)

Blindheim, Johan

1990-09-01

At least two types of intermediate water propagate into the Norwegian Sea from the Iceland and Greenland seas. North Icelandic Winter Water flows along the slope of the Faroe-Iceland Ridge towards the Faroes. The distribution of this intermediate water is limited to the southern Norwegian Sea. The second type intrudes between the bottom water and the Atlantic Water, and can be traced as a slight salinity minimum of the entire area of the Norwegian Sea. There seems to be along-isopycnal advection of this water type along the Arctic Front from both the Iceland and Greenland Seas. Although the salinity minimum is less distinct along the slope of the continental shelf than in the western Norwegian Sea, this intermediate water separates the deep water and the Atlantic Water, and prohibits direct mixing of these two water masses.

41 CFR 101-27.204 - Types of shelf-life items.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Types of shelf-life items...-Management of Shelf-Life Materials § 101-27.204 Types of shelf-life items. Shelf-life items are classified as nonextendable (Type I) and extendable (Type II). Type I items have a definite storage life after which the item...

41 CFR 101-27.204 - Types of shelf-life items.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Types of shelf-life items...-Management of Shelf-Life Materials § 101-27.204 Types of shelf-life items. Shelf-life items are classified as nonextendable (Type I) and extendable (Type II). Type I items have a definite storage life after which the item...

41 CFR 101-27.204 - Types of shelf-life items.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Types of shelf-life items...-Management of Shelf-Life Materials § 101-27.204 Types of shelf-life items. Shelf-life items are classified as nonextendable (Type I) and extendable (Type II). Type I items have a definite storage life after which the item...

41 CFR 101-27.204 - Types of shelf-life items.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 2 2013-07-01 2012-07-01 true Types of shelf-life items...-Management of Shelf-Life Materials § 101-27.204 Types of shelf-life items. Shelf-life items are classified as nonextendable (Type I) and extendable (Type II). Type I items have a definite storage life after which the item...

Dibble Ice Shelf

NASA Image and Video Library

2013-06-13

This photo, aken onboard a National Science Foundation/NASA chartered Twin Otter aircraft, shows the ice front of Dibble Ice Shelf, East Antarctica, a significant melt water producer from the Wilkes Land region, East Antarctica.

Seismicity within a propagating ice shelf rift: the relationship between icequake locations and ice shelf structure

USGS Publications Warehouse

Heeszel, David S.; Fricker, Helen A.; Bassis, Jeremy N.; O'Neel, Shad; Walter, Fabian

2014-01-01

Iceberg calving is a dominant mass loss mechanism for Antarctic ice shelves, second only to basal melting. An important known process involved in calving is the initiation and propagation of through-penetrating fractures called rifts; however, the mechanisms controlling rift propagation remain poorly understood. To investigate the mechanics of ice-shelf rifting, we analyzed seismicity associated with a propagating rift tip on the Amery Ice Shelf, using data collected during the Austral summers of 2004-2007. We investigated seismicity associated with fracture propagation using a suite of passive seismological techniques including icequake locations, back projection, and moment tensor inversion. We confirm previous results that show that seismicity is characterized by periods of relative quiescence punctuated by swarms of intense seismicity of one to three hours. However, even during periods of quiescence, we find significant seismic deformation around the rift tip. Moment tensors, calculated for a subset of the largest icequakes (MW > -2.0) located near the rift tip, show steeply dipping fault planes, horizontal or shallowly plunging stress orientations, and often have a significant volumetric component. They also reveal that much of the observed seismicity is limited to the upper 50 m of the ice shelf. This suggests a complex system of deformation that involves the propagating rift, the region behind the rift tip, and a system of rift-transverse crevasses. Small-scale variations in the mechanical structure of the ice shelf, especially rift-transverse crevasses and accreted marine ice, play an important role in modulating the rate and location of seismicity associated with propagating ice shelf rifts.

Morphometric comparison of Icelandic lava shield volcanoes versus selected Venusian edifices

NASA Technical Reports Server (NTRS)

Garvin, James B.; Williams, Richard S., Jr.

1993-01-01

Shield volcanoes are common landforms on the silicate planets of the inner Solar System, and a wide variety have recently been documented on Venus by means of Magellan observations. In this report, we emphasize our recently completed morphometric analysis of three representative Icelandic lava shields: the classic Skjaldbreidur edifice, the low-reflief Lambahraun feature, and the monogenetic Sandfellshaed shield, as the basis for comparison with representative venusian edifices (greater than 60 km in diameter). Our detailed morphometric measurements of a representative and well-studied set of Icelandic volcanoes permits us to make comparisons with our measurements of a reasonable subset of shield-like edifices on Venus on the basis of Magellan global radar altimetry. Our study has been restricted to venusian features larger than approximately 60 km in basal diameter, on the basis of the minimum intrinsic spatial resolution (8 km) of the Magellan radar altimetry data. Finally, in order to examine the implications of landform scaling from terrestrial simple and composite shields to larger venusian varieties, we have considered the morphometry of the subaerial component of Mauna Loa, a type-locality for a composite shield edifice on Earth.

The Temperature of the Icelandic Mantle Plume from Aluminium-in-Olivine Thermometry

NASA Astrophysics Data System (ADS)

Matthews, S.; Shorttle, O.; Maclennan, J.

2015-12-01

Temperature is a key control on the physical properties of the mantle, in particular the extent of melting during upwelling. It is not, however, a unique control on many of the parameters used to estimate mantle temperature. For example igneous crustal thickness which has often been used as a first-order proxy for mantle temperature, is also affected by mantle lithology and plume flux. Alternatives to geophysical indicators of mantle temperature are petrological thermometers. However, these record crystallisation temperatures, therefore a series of assumptions about the coupled melt- solid mantle thermal history must be made when calculating back to mantle potential temperature. In this study we investigate how these assumptions may affect mantle temperature estimates and how crystallisation temperatures may offer insights into the melting and melt transport processes, focussing on a new set of crystallisation temperature estimates we have made on primitive Icelandic basalts.We used the aluminium-in-olivine thermometer of Coogan et al. (2014) to estimate crystallisation temperatures of olivine phenocrysts in a suite of samples from the Northern Volcanic Zone (NVZ) of Iceland. The data suggest that within a single volcanic system crystallisation temperature depends strongly on the olivine forsterite content, thus the history of melt evolution, and how the eruption samples this, must be considered when extrapolating to mantle temperature. To assess the influence of the assumptions required to obtain mantle temperature we constructed a simple thermal model incorporating varying proportions of lherzolite, pyroxenite and harzburgite undergoing decompression melting. A trade off between increasing mantle temperature and decreasing pyroxenite (or increasing harzburgite) in the source is observed. Using this dataset and our model, calculations reveal a potential temperature of 1470±130 °C for Iceland, and a temperature excess of 150±40 °C relative to ambient mantle

Vertical plate motions from ancient buried landscapes: Constraints on Icelandic plume evolution

NASA Astrophysics Data System (ADS)

Stucky de Quay, G.

2016-12-01

Convection in the Earth's mantle is strongly time-dependent (Ra 106-108). In regions that are dynamically supported, uplift and subsidence histories might therefore contain information about evolution of mantle convection. We examine uplift and subsidence histories of sedimentary basins fringing NW Europe, close to the Icelandic plume, where it has been shown short-term vertical motions disrupt post-rift thermal subsidence. These sedimentary basins contain ancient (59-53 Ma) buried fluvial landscapes which developed during inception of the Icelandic plume. Stratigraphic and seismic reflection data indicate that these terrestrial landscapes were incised by 100s of meters in only a few million years and were then rapidly submerged. We extracted a landscape buried beneath 1.5 km of sedimentary rock in the Bressay region, offshore eastern Scotland. This landscape was mapped using a three-dimensional 9000 km2 seismic dataset and seven exploration wells. First, the buried landscape was mapped using every inline and cross line (horizontal resolution 12 m). Second, the landscape was depth converted and decompacted using check-shot data. Third, drainage patterns were reconstructed by calculating flow directions across the mapped landscape. River profiles were extracted from these drainage patterns and contain three knickzones analogous to those documented in an older buried landscape in the Faereo-Shetland Basin, 400 km to the west. Fourth, we reinterpreted dinocyst records to determine the age of our landscape, allowing us to constrain erosion rates. Finally, our drainage inventory was inverted for uplift rate as a function of space and time. Results indicate three uplift events occurred between 55-57 Ma, resulting in a total cumulative uplift of 400 m. We combine these results with estimates of uplift in nearby regions to constrain the behavior of the incipient Icelandic plume both in a temporal and spatial context.

The puzzle of the 1996 Bárdarbunga, Iceland, earthquake: no volumetric component in the source mechanism

USGS Publications Warehouse

Tkalcic, Hrvoje; Dreger, Douglas S.; Foulger, Gillian R.; Julian, Bruce R.

2009-01-01

A volcanic earthquake with Mw 5.6 occurred beneath the Bárdarbunga caldera in Iceland on 29 September 1996. This earthquake is one of a decade-long sequence of  events at Bárdarbunga with non-double-couple mechanisms in the Global Centroid Moment Tensor catalog. Fortunately, it was recorded well by the regional-scale Iceland Hotspot Project seismic experiment. We investigated the event with a complete moment tensor inversion method using regional long-period seismic waveforms and a composite structural model. The moment tensor inversion using data from stations of the Iceland Hotspot Project yields a non-double-couple solution with a 67% vertically oriented compensated linear vector dipole component, a 32% double-couple component, and a statistically insignificant (2%) volumetric (isotropic) contraction. This indicates the absence of a net volumetric component, which is puzzling in the case of a large volcanic earthquake that apparently is not explained by shear slip on a planar fault. A possible volcanic mechanism that can produce an earthquake without a volumetric component involves two offset sources with similar but opposite volume changes. We show that although such a model cannot be ruled out, the circumstances under which it could happen are rare.

Estimation of shelf life of wikau maombo brownies cake using Accelerated Shelf Life Testing (ASLT) method with Arrhenius model

NASA Astrophysics Data System (ADS)

Wahyuni, S.; Holilah; Asranudin; Noviyanti

2018-02-01

The shelf life of brownies cake made from wikau maombo flour was predicted by ASLT method through the Arrhenius model. The aim of this study was to estimate the shelf life of brownies cake made from wikau maombo flour. The storage temperature of brownies cake was carried out at 20°C, 30°C and 45°C. The results showed that TBA (Thio Barbaturic Acid) number of brownies cake decreased as the storage temperature increase. Brownies stored at 20°C and 30°C were overgrown with mold on the storage time of six days. Brownies product (WT0 and WT1) had shelf life at 40°C approximately six and fourteen days, respectively. Brownies made from wikau maombo and wheat flour (WT1) was the best product with had the longest of shelf life about fourteen days.

Impacts of the Larsen-C Ice Shelf calving event

NASA Astrophysics Data System (ADS)

Hogg, Anna E.; Gudmundsson, G. Hilmar

2017-08-01

A giant iceberg has calved off the Larsen-C Ice Shelf, the largest remaining ice shelf on the Antarctic Peninsula, reducing its total area by ~10%. Whilst calving events are a natural phenomenon and thus not necessarily indicative of changing environmental conditions, such events can impact ice-shelf stability.

Shelf life prediction of apple brownies using accelerated method

NASA Astrophysics Data System (ADS)

Pulungan, M. H.; Sukmana, A. D.; Dewi, I. A.

2018-03-01

The aim of this research was to determine shelf life of apple brownies. Shelf life was determined with Accelerated Shelf Life Testing method and Arrhenius equation. Experiment was conducted at 25, 35, and 45°C for 30 days. Every five days, the sample was analysed for free fatty acid (FFA), water activity (Aw), and organoleptic acceptance (flavour, aroma, and texture). The shelf life of the apple brownies based on FFA were 110, 54, and 28 days at temperature of 25, 35, and 45°C, respectively.

New Joint Geochemical-Geophysical Record of Time-Dependent Mantle Convection South of Iceland

NASA Astrophysics Data System (ADS)

Jones, S. M.; Murton, B. J.; Fitton, J. G.; White, N. J.; Scientific Team Of Rv Celtic Explorer Cruise Ce0806

2010-12-01

Upper mantle convection is expected to be time-dependent because the mantle Rayleigh number is super-critical by at least 3 orders of magnitude. The North Atlantic V-Shaped Ridges (VSRs) provide a long, spatially extensive and clear record of unsteady mantle convection over time periods of 0.1 to 10 million years. VSRs are diachronous ridges of thick crust formed at the Mid Atlantic Ridge to the north and south of Iceland. Ever since their discovery, it has been generally agreed that this diachronous geometry results from melting anomalies that propagate outward from Iceland within the asthenosphere. The solid earth cycles that generate the VSRs also appear to modulate Atlantic oceanic circulation, since the VSR record correlates well with the % Northern Component Water proxy. Knowledge of geochemical variability associated with the VSRs is lacking in comparison with available geophysical and oceanographic records. Here we report dredged basalt samples obtained during RV Celtic Explorer cruise CE0806 (April-May 2008). Together with an earlier dredged dataset, we now have a record of basalt geochemistry covering intersections of 2 V-Shaped Ridge/Trough pairs with the Mid Atlantic Ridge, as well as a transect along a VSR crest. (1) Along the Mid Atlantic Ridge, spatial variations in trace element concentrations and ratios correlate very well with VSR records from bathymetry and gravity. Minima in incompatible trace element concentrations and in ratios such as La/Sm and Zr/Y correlate with maxima in crustal thickness. There is no associated systematic variation in Nd or Sr isotopes. Observations suggest that VSR melting anomalies are caused by variations in temperature rather than composition of the mantle source. (2) VSR melting anomalies propagate out to at least 1400 km from Iceland, well into the region where fracture zones obscure the topographic and gravitational expressions of the VSRs. A value of >1400 km for the radius of plume head measured at the mid

'I'm Happy if I Can Help'. Public views on future medicines and gene-based therapy in Iceland.

PubMed

Traulsen, Janine M; Bjornsdóttir, Ingunn; Almarsdóttir, Anna Birna

2008-01-01

To explore lay perceptions about medicine and drug therapy (including gene-based therapy) in the present and in the future. Following almost a year of national debate, the Icelandic parliament passed the Health Sector Database (HSD) Act in 1998. No single issue has been as much debated in Iceland as this database. Despite the explosion of popular and scientific literature in the field of bioethics, there is still a paucity of research concerning 'lay' contributions to the debates. The study was designed as a qualitative study. Focus groups (FGs) were conducted followed by one-on-one interviews with the FG moderator. PARTICIPANTS were asked to comment on a future scenario consisting of predictions concerning the consequence of the Human Genome Project over the next 40 years. Forty-two persons participated in eight FGs in Iceland. The Icelandic moderator was interviewed in English after each group. The lay public was relatively optimistic with regard to the future of drugs and gene-based therapy. Reasons for this optimism can be found in a basic trust and belief in the welfare state and the health system. These results are not consistent with studies carried out in other countries where the public appears to be focused on the negative effects of genetic research and the threats to privacy. Most participants expressed concern about potential problems with regard to social and equity issues, whereas the HSD controversy, a discourse based on the rhetoric of bioethics, was at variance with the issues focused on by the lay public. (c) 2008 S. Karger AG, Basel

The Role of Basal Channels in Ice Shelf Calving.

NASA Astrophysics Data System (ADS)

Dow, C. F.; Lee, W. S.; Greenbaum, J. S.; Greene, C. A.; Blankenship, D. D.; Poinar, K.; Forrest, A.; Young, D. A.; Zappa, C. J.

2017-12-01

Increased rates of ice shelf break-up drives acceleration of grounded glacial ice into the ocean, resulting in sea-level rise. Ice shelves are vulnerable to thinning, which make them more susceptible to calving. Here, we examine basal channels under three ice shelves that locally thin the ice and drive formation of transverse ice shelf fractures. The basal channels also cause surface depressions due to hydrostatic buoyancy effects and can draw in surface water to form rivers. These rivers exacerbate thinning by surface melting and hydraulic loading, and can accelerate rifting when they flow into the transverse fractures. Our investigation focuses on Nansen Ice Shelf in the Ross Sea Embayment, East Antarctica. We use ice-sounding radar and single-beam laser altimeter data from two aerogeophysical campaigns conducted in 2011 and 2014, ice surface DEM reconstruction, and satellite imagery analysis, to examine the role of a substantial basal channel in the stability of this ice shelf. Nansen Ice Shelf calved two large icebergs totaling 214 km2 in area in April 2016. The transverse fracture that eventually rifted to form these icebergs initiated directly over the basal channel in 1987. In years when surface water formed on Nansen Ice Shelf, a river flowed into the transverse fracture. In November 2016, we identified a new fracture over the basal channel during in-situ data collection. We compare the Nansen Ice Shelf fractures with those at other vulnerable ice-shelf systems, including Petermann Glacier in Greenland and Totten Glacier in East Antarctica, to evaluate the role that basal channels may play in simultaneous basal and surface weakening and their consequent effect on ice-shelf rifting and stability.

Morphological Variation among Betula nana (diploid), B. pubescens (tetraploid) and their Triploid Hybrids in Iceland

PubMed Central

Thórsson, Æ. Th.; Pálsson, S.; Sigurgeirsson, A.; Anamthawat-Jónsson, K.

2007-01-01

Background and Aims Introgressive hybridization between two co-existing Betula species in Iceland, diploid dwarf birch B. nana and tetraploid downy birch B. pubescens, has been well documented. The two species are highly variable morphologically, making taxonomic delineation difficult despite stable ploidy levels. Here an analysis is made of morphological variation within each ploidy group with an aim to establishing a reliable means to distinguish the species. Methods Plant materials were collected from 14 woodlands in Iceland. The plants were identified based on 2n chromosome numbers. Morphological variation in species-specific characters within each ploidy group was analysed qualitatively and quantitatively. The morphological index was based on eight discrete characters, whereas the multivariate analysis was based on nine leaf variables. Key Results Of the 461 plants examined, 9·5 % were found to be triploid hybrids. The three ploidy groups were morphologically distinguishable but their variation overlapped. The diploid, triploid and tetraploid groups had average scores of 1·3, 4·1 and 8·3, respectively, in the morphology index scale from 0 (B. nana) to 13 (B. pubescens). A linear discriminant analysis also revealed significant separation among the three ploidy groups and the model assigned 96 % and 97 % of the B. nana and B. pubescens individuals correctly. The triploid hybrids were difficult to predict since only half of them could be assigned correctly. Leaf length was the most useful variable identifying triploid hybrids. Geographical patterns within the ploidy groups could partly be explained by differences in mean July temperature. Conclusions Hybridization between B. nana and B. pubescens is widespread in Iceland. The species can be distinguished from each other morphologically, and from the triploid hybrids. The overlapping morphological variation indicates bidirectional introgression between the two species via triploid hybrids. Iceland could be

Ross Ice Shelf

Atmospheric Science Data Center

2013-04-16

... Larger Image According to researchers funded by the National Science Foundation, several penguin colonies near the Ross Ice Shelf, ... Hut Point Peninsula. For a press release from the National Science Foundation containing additional details and MISR imagery ...

Methods for preservation and extension of shelf life.

PubMed

Gould, G W

1996-11-01

There is potential for spoilage of all foods at some rate or other following harvest, slaughter or manufacture and spoilage may occur at any of the stages between the acquisition of raw materials and the eventual consumption of a food product. These stages include processing, packaging, distribution, retail display, transport, storage and use by the consumer. They are under varying degrees of control that aim to deliver a satisfactory shelf life, to ensure that the finally-consumed product is of high quality and to ensure that it is safe. Spoilage may be caused by a wide range of reactions including some that are essentially physical, some that are chemical, some enzymic and some microbiological. The various forms of microbiological spoilage are preventable to a large degree by a wide range of preservation techniques, most of which act by preventing or inhibiting microbial growth (e.g., chilling, freezing, drying, curing, conserving, vacuum packing, modified atmosphere packing, acidifying, fermenting and adding preservatives). A smaller number of techniques act by inactivating microorganisms (e.g., pasteurization, sterilization and irradiation). Additional techniques restrict the access of microorganisms to products (e.g., aseptic processing and packaging. A major trend is that new and emerging preservation techniques which are coming into use or are under development include more that act by inactivation (e.g., ultrahigh pressure, electroporation, manothermosonication and addition of bacteriolytic enzymes). A further trend is towards the use of procedures that deliver products that are less heavily preserved, have higher quality, are more natural, freer from additives and nutritionally healthier. Less severe preservation procedures are therefore being developed that make use of preservative factors in combinations to deliver (a) less damage to product quality (hurdle technologies); (b) new methods of heating that are better controlled and therefore deliver milder

The role of basement inheritance faults in the recent fracture system of the inner shelf around Alboran Island, Western Mediterranean

NASA Astrophysics Data System (ADS)

Maestro-González, A.; Bárcenas, P.; Vázquez, J. T.; Díaz-Del-Río, V.

2008-02-01

Fractures associated with volcanic rock outcrops on the inner shelf of Alboran Island, Western Mediterranean, were mapped on the basis of a side-scan sonar mosaic. Absolute maximum fracture orientation frequency is NW SE to NNW SSE, with several sub-maxima oriented NNE SSW, NE SW and ENE WSW. The origin of the main fracture systems in Neogene and Quaternary rocks of the Alboran Basin (south Spain) appears to be controlled by older structures, namely NE SW and WNW ESE to NW SE faults which cross-cut the basement. These faults, pre-Tortonian in origin, have been reactivated since the early Neogene in the form of strike-slip and extensional movements linked to the recent stress field in this area. Fracture analysis of volcanic outcrops on the inner continental shelf of Alboran Island suggests that the shelf has been deformed into a narrow shear zone limited by two NE SW-trending, sub-parallel high-angle faults, the main orientation and density of which have been influenced by previous WNW ESE to NW SE basement fractures.

Significance of a Shelf-wide Dissolution Event during the Paleocene-Eocene Thermal Maximum, Maryland and New Jersey, USA

NASA Astrophysics Data System (ADS)

Bralower, T. J.; Kump, L. R.; Robinson, M. M.; Self-Trail, J. M.; Zachos, J. C.

2016-12-01

Continental-shelf sediments of the US Atlantic margin experienced a brief episode of carbonate dissolution during the onset of the Paleocene-Eocene Thermal Maximum (PETM). Dissolution is represented by reduced percentages of carbonate, and calcareous microfossil distribution and preservation trends, in cores from Maryland and New Jersey. The base and the top of the dissolution zone are abrupt compared to the gradual nature of the onset of the carbon isotope excursion (CIE). The thickness of the dissolution zone varies from 9 cm in the Bass River core (outer paleoshelf) to 1.6 m in the CamDor core (middle paleoshelf). The decrease in %CaCO3 suggests dissolution locally removed 83 to 100% of the initial biogenic carbonate. Shelf-wide dissolution during the onset of the PETM may be a regional event, associated, for example, with eutrophication. Samples from across the paleoshelf contain abundant fine-grained framboidal pyrite, which suggests photic-zone euxinia occurred before, during, and after the dissolution event. Dissolution may also be associated with oxidation of this pyrite during later exposure to oxidizing groundwaters, although the restricted duration of the dissolution interval argues against this. Alternatively, the dissolution event may have global significance related to surface ocean-water acidification or shoaling of the calcite compensation depth (CCD) to shelf depths. The event began near the onset of the CIE on the shelf, whereas dissolution in deep-sea sections began later. Earlier shelf dissolution is consistent with surface ocean acidification while later deep-sea dissolution is thought to be associated with shoaling of the CCD. In our presentation, we weigh evidence for each of these possibilities and test them using the global dataset.

Magma plumbing for the 2014-2015 Holuhraun eruption, Iceland

NASA Astrophysics Data System (ADS)

Geiger, Harri; Mattsson, Tobias; Deegan, Frances M.; Troll, Valentin R.; Burchardt, Steffi; Gudmundsson, Ólafur; Tryggvason, Ari; Krumbholz, Michael; Harris, Chris

2016-08-01

The 2014-2015 Holuhraun eruption on Iceland was located within the Askja fissure swarm but was accompanied by caldera subsidence in the Bárðarbunga central volcano 45 km to the southwest. Geophysical monitoring of the eruption identified a seismic swarm that migrated from Bárðarbunga to the Holuhraun eruption site over the course of two weeks. In order to better understand this lateral connection between Bárðarbunga and Holuhraun, we present mineral textures and compositions, mineral-melt-equilibrium calculations, whole rock and trace element data, and oxygen isotope ratios for selected Holuhraun samples. The Holuhraun lavas are compositionally similar to recorded historical eruptions from the Bárðarbunga volcanic system but are distinct from the historical eruption products of the nearby Askja system. Thermobarometry calculations indicate a polybaric magma plumbing system for the Holuhraun eruption, wherein clinopyroxene and plagioclase crystallized at average depths of ˜17 km and ˜5 km, respectively. Crystal resorption textures and oxygen isotope variations imply that this multilevel plumbing system facilitated magma mixing and assimilation of low-δ18O Icelandic crust prior to eruption. In conjunction with the existing geophysical evidence for lateral migration, our results support a model of initial vertical magma ascent within the Bárðarbunga plumbing system followed by lateral transport of aggregated magma batches within the upper crust to the Holuhraun eruption site.

Trondhjemitic melts produced by in-situ differentiation of a tholeiitic lava flow, Reykjanes Peninsula, Iceland.

NASA Astrophysics Data System (ADS)

Martin, E.; Sigmarsson, O.

2006-12-01

How the continental crust began to form early in Earth's history is unconstrained. However, it is reasonable to presume that higher heat flow in the past, resulted in more frequent interaction of mantle plumes and mid- oceanic ridges. If true, then Iceland could be a good analogue for processes occurring on Earth at its youth stage. This is supported by the relatively high abundance of silicic rocks in Iceland but their rarity on other oceanic hot spots. The origin of Icelandic silicic rocks has been a subject of a lively debate but has been shown to be principally formed by partial melting of hydrothermally altered basaltic crust. However, in rare cases, their origin by fractional crystallization from mantle derived basalts is suggested. Segregation veins in lava flows frequently contain interstitial glasses of silicic compositions. Moreover, they allow an exceptional overview of the fractional crystallization mechanism. These veins form by gas filter pressing during cooling and degassing of solidifying lava flows, after approximately 50% fractional crystallization of anhydrous minerals. Pairs of samples, host lava and associated segregation veins, from Reykjanes Peninsula (Iceland), Lanzarote (Canary Island) and Masaya's volcano (Nicaragua), allow the assessment of a near-complete fractional crystallization of olivine tholeiitic basalt at pressure close to one atmosphere. Interstitial glass patches in segregation veins represent the final product of this process (80 97 % of fractional crystallization). These ultimate liquids are of granitic composition in the case of Lanzarote and Masaya but overwhelmingly trondhjemitic at Reykjanes. It appears that the initial K2O/Na2O of the basaltic liquid controls the evolution path of the residual liquid composition produced at pressure close to 0.1 MPa (1 bar). Granitic liquids are generated from basalts of high initial K2O/Na2O whereas low initial K2O/Na2O leads to trondhjemitic compositions. The trondhjemitic composition

InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

NASA Astrophysics Data System (ADS)

Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

2014-12-01

Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and S�

Instructional Leadership in Compulsory Schools in Iceland and the Role of School Principals

ERIC Educational Resources Information Center

Hansen, Börkur; Lárusdóttir, Steinunn Helga

2015-01-01

The purpose of this paper is to present findings from a study of instructional leadership in 20 Icelandic compulsory schools. More specifically, the perceptions of staff concerning supervision of instruction, and the views of principals regarding their role as supervisors of instructional development. Data was collected with questionnaires from…

Leading the Small Rural School in Iceland and Australia: Building Leadership Capacity

ERIC Educational Resources Information Center

Wildy, Helen; Siguräardóttir, Sigríäur Margrét; Faulkner, Robert

2014-01-01

This study builds on a set of Australian case studies exploring the impact of Place on the work of principals and of the importance of Place in the preparation and development of principals. The project compares the ways that principals in Iceland and Australia build leadership capacity in small rural schools. Leaders of small schools in both…

Shelf Sea Oxygen Dynamics: A year of Glider Measurements

NASA Astrophysics Data System (ADS)

Williams, C. A. J.; Palmer, M.; Mahaffey, C.; Jardine, J.

2016-02-01

Oxygen (O) is involved in most biogeochemical processes in the ocean, and dissolved oxygen (DO) is a well-established indicator for biological activity via the estimate of apparent oxygen utilisation (AOU). In the deep waters of the open ocean, the AOU provides a valuable insight into the ocean's biological carbon pump. However, in the physically dynamic and highly productive shallow shelf seas, interpretation of the O distribution and the magnitude of AOU is complex. Physical processes, such as diapycnal mixing, entrainment and horizontal advection act to ventilate waters below the thermocline and thus increase O and decrease AOU. In contrast, biological remineralisation of organic material below the thermocline will consume O and increase AOU. Here, we use 1 year of high-resolution data from >20 glider deployments in the seasonally stratified NW European Shelf Sea to identify and quantify the physical and biological processes that control the DO distribution and magnitude of AOU in shelf seas. A 200km transect between the shelf edge and the central Celtic Sea (CCS) was repeated between November 2014 and August 2015, thus capturing key periods in the seasonal cycling in shelf seas, specifically the onset of stratification, the spring bloom, stratified summer period and breakdown of stratification. The gliders collected data for DO, temperature, salinity, chlorophyll fluorescence, CDOM, backscatter and turbulence. In addition, direct measurements of turbulent dissipation from the Ocean Microstructure Glider deployed during the campaign provided estimates of mixing at CCS and the shelf break, allowing accurate quantification of the vertical fluxes of O. At the end of the stratified period the DO concentration was higher and AOU was lower at the shelf break (80 µM) compared to at CCS on shelf (>95 µM) (Fig 1). Estimates of vertical DO fluxes indicate that this horizontal variation in DO and AOU was partly attributed to enhanced mixing via internal waves at the

Physical and chemical properties of young soils of the Icelandic highlands

NASA Astrophysics Data System (ADS)

Gísladóttir, Guðrún; Mankasingh, Utra

2015-04-01

Most of the Icelandic soils are of volcanic origin, classified as andisols (carbon content 1-12%), many of which are strongly affected by erosion and so, formation of new soils is of great interest. The effect of land cover type on the weathering patterns and the formation of new soils are of interest. The southern Icelandic highlands are characterised by harsh climate, shallow soils and limited vegetation cover. We hypothesise that in the highland regions of Iceland the progression of land cover from unvegetated to vegetated sites will impact soil development. This study describes the physical and chemical properties of highland soils in Iceland. Soil samples were collected from 12 sites in September 2013, nine sites were fully vegetated and three unvegetated: grassland (G1-G8), with moss, Carex Bigelowii and dwarf shrubs, sandy fluvial wetland (S) and unvegetated gravels (M1-M3). All soils with vegetative cover were characterized by weak or structureless soil ranging in texture from loamy sand to silty clay loam, while at unvegetated sites soil texture was structureless and sandy. On average, the bulk density of soils (range 0.53 - 1.16 g cm-3) were lower at vegetated sites than unvegetated sites. The soil depth is greater in the vegetated sites, indicating greater soil development. The average % carbon (%C), % nitrogen (%N), overall % soil organic matter (%SOM), of vegetated sites were higher than for unvegetated sites, indicating the difference in soil development: vegetated sites (mean), 1.60%C, 0.10%N, 4.9%SOM; unvegetated sites (mean), 0.27%C, 0.02%N, 1.81%SOM. All soils had significant amounts of amorphous clay minerals such as allophone, imogolite, ferrihydrite or aluminium-humus complexes and also high aluminium and iron percentages, and high phosphate retention. All of which are characteristic for andisols. There were strong associations between Fe and Al and the soil C, which are indicative of Al and Fe complexed with humus or allophane and ferrihydrite

Modelling the bathymetry of the Antarctic continental shelf

USGS Publications Warehouse

ten Brink, Uri S.; Rogers, William P.; Kirkham, R.M.

1992-01-01

Continental shelves are typically covered by relatively shallow waters (<200 m) which deepen gradually from the coast to the shelf edge. The continental shelf around Antarctica is deeper than normal (400-700m) and is characterized in many areas by a nearshore trough (up to 1 km deep) that gradually shallows toward the shelf edge. We examine the cause for the unusual shelf bathymetry of Antarctica by 2-D numerical models that simulate the bathymetry along seismic line ODP-119 in Prydz Bay. Line ODP-119 was chosen because it is tied to to 5 ODP boreholes, and because the margin underwent little recent tectonic activity or changes in the glacial drainage pattern. The numerical models incorporate several factors that are likely to influence the bathymetry, such as the load of the ice cap, the isostatic response of the lithosphere, thermal and tectnoic subsidence of the margin, sea level changes, and the patterns of erosion and sedimentation across the margin. The models show that the observed bathymetry can be produced almost entirely by the sum of the outer-shelf sediment loading and inner-shelf unloading and by the load of the slope sediments. A simple statistical mdoel demonstrates that this distribution pattern of erosion and deposition can be generated by multiple cycles of ice sheet advances across the shelf, whereby in each cycle a thin (a few tens of meters) uniform layer of sediments is eroded from under the ice sheet and is redeposited seaward of the grounding line.

Sub-ice-shelf sediments record history of twentieth-century retreat of Pine Island Glacier [Sub-ice shelf sediments record 20 th century retreat history of Pine Island Glacier

DOE PAGES

Smith, J. A.; Andersen, T. J.; Shortt, M.; ...

2016-11-23

The West Antarctic Ice Sheet is one of the largest potential sources of rising sea levels. Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line—which marks the boundary between grounded ice and floating ice shelf—is underway. Understanding this recent retreat requires a detailed knowledge of grounding-line history, but the locations of the grounding line before the advent of satellite monitoring in the 1990s are poorly dated. In particular, a history of grounding-line retreatmore » is required to understand the relative roles of contemporaneous ocean-forced change and of ongoing glacier response to an earlier perturbation in driving ice-sheet loss. Here we show that the present thinning and retreat of Pine Island Glacier in West Antarctica is part of a climatically forced trend that was triggered in the 1940s. Our conclusions arise from analysis of sediment cores recovered beneath the floating Pine Island Glacier ice shelf, and constrain the date at which the grounding line retreated from a prominent seafloor ridge. We find that incursion of marine water beyond the crest of this ridge, forming an ocean cavity beneath the ice shelf, occurred in 1945 (±12 years); final ungrounding of the ice shelf from the ridge occurred in 1970 (±4 years). The initial opening of this ocean cavity followed a period of strong warming of West Antarctica, associated with El Niño activity. Furthermore our results suggest that, even when climate forcing weakened, ice-sheet retreat continued.« less

Sub-ice-shelf sediments record history of twentieth-century retreat of Pine Island Glacier [Sub-ice shelf sediments record 20 th century retreat history of Pine Island Glacier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, J. A.; Andersen, T. J.; Shortt, M.

The West Antarctic Ice Sheet is one of the largest potential sources of rising sea levels. Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line—which marks the boundary between grounded ice and floating ice shelf—is underway. Understanding this recent retreat requires a detailed knowledge of grounding-line history, but the locations of the grounding line before the advent of satellite monitoring in the 1990s are poorly dated. In particular, a history of grounding-line retreatmore » is required to understand the relative roles of contemporaneous ocean-forced change and of ongoing glacier response to an earlier perturbation in driving ice-sheet loss. Here we show that the present thinning and retreat of Pine Island Glacier in West Antarctica is part of a climatically forced trend that was triggered in the 1940s. Our conclusions arise from analysis of sediment cores recovered beneath the floating Pine Island Glacier ice shelf, and constrain the date at which the grounding line retreated from a prominent seafloor ridge. We find that incursion of marine water beyond the crest of this ridge, forming an ocean cavity beneath the ice shelf, occurred in 1945 (±12 years); final ungrounding of the ice shelf from the ridge occurred in 1970 (±4 years). The initial opening of this ocean cavity followed a period of strong warming of West Antarctica, associated with El Niño activity. Furthermore our results suggest that, even when climate forcing weakened, ice-sheet retreat continued.« less

Linking interannual variability in shelf bottom water properties to the California Undercurrent and local processes in the Pacific Northwest

NASA Astrophysics Data System (ADS)

Stone, H. B.; Banas, N. S.; Hickey, B. M.; MacCready, P.

2016-02-01

The Pacific Northwest coast is an unusually productive area with a strong river influence and highly variable upwelling-favorable and downwelling-favorable winds, but recent trends in hypoxia and ocean acidification in this region are troubling to both scientists and the general public. A new ROMS hindcast model of this region makes possible a study of interannual variability. This study of the interannual temperature and salinity variability on the Pacific Northwest coast is conducted using a coastal hindcast model (43°N - 50°N) spanning 2002-2009 from the University of Washington Coastal Modeling Group, with a resolution of 1.5 km over the shelf and slope. Analysis of hindcast model results was used to assess the relative importance of source water variability, including the poleward California Undercurrent, local and remote wind forcing, winter wind-driven mixing, and river influence in explaining the interannual variations in the shelf bottom layer (40 - 80 m depth, 10 m thick) and over the slope (150 - 250 m depth, <100 km from shelf break) at each latitude within the model domain. Characterized through tracking of the fraction of Pacific Equatorial Water (PEW) relative to Pacific Subarctic Upper Water (PSUW) present on the slope, slope water properties at all latitudes varied little throughout the time series, with the largest variability due to patterns of large north-south advection of water masses over the slope. Over the time series, the standard deviation of slope temperature was 0.09 ˚C, while slope salinity standard deviation was 0.02 psu. Results suggest that shelf bottom water interannual variability is not driven primarily by interannual variability in slope water as shelf bottom water temperature and salinity vary nearly 10 times more than those over the slope. Instead, interannual variability in shelf bottom water properties is likely driven by other processes, such as local and remote wind forcing, and winter wind-driven mixing. The relative

Frequency, triggering factors and possible consequences of mass movements on outlet glaciers in Iceland.

NASA Astrophysics Data System (ADS)

Saemundsson, Thorsteinn; Margeirsson, Guðbjörn

2016-04-01

During the last 15 years several mass movements of various size and origin, e.g. rock avalanches, rock slides and debris slides have been observed to have fall on outlet glaciers in Iceland. This should not come as a surprise in this type of glacial environment, but in a way it does. When looking at the history only few mass movements are recorded to have fall on outlet glaciers in Iceland, during the decades before the year 2000 or since 1960. This "lack of mass movements" can be explained by the fact that fewer observations and monitoring were done in the past, but is it so or are we seeing increasing activity? Looking at the distribution of the known mass movements, two activity periods cam be identified. The former one around 1970 and the second one starting around 2000 and is still ongoing. Both of these periods are characterized by warmer climate leading to retreating phases of glaciers. Two larger mass movements are known from these two retreating periods. The former one occurred in January 1967. Then a large rockslide fell on the snout and into the glacial lake of the Steinholtsjökull outlet glacier in the northern side of the Eyjafjallajökull ice cap. The rockslide broke up the snout of the glacier and caused large floodwave bursting down the Steinholtsdalur valley transporting large volume of sediments down its path. The later one occurred in 2007, when a large rockavalanche fell on the Morsárjökull outlet glacier, in the southern side of the Vatnajökull ice cap. The avalanche debris covered around 1/5 of the glacier surface. Today the retreat and thinning of glaciers in Iceland are extremely rapid. The consequences of such a rapid retreat are e.g. unstable valley slopes surrounding the outlet glaciers, both in loose sediments and bedrock, thawing of mountain permafrost and not least formation of glacial lakes in front of the rapid retreating ice margins. Such conditions can become extremely hazardous, as seen by the above mentioned examples, both

Simultaneous Quantification of Temperature, Pyroxenite Abundance, and Upwelling Rates in the Iceland Mantle Source

NASA Astrophysics Data System (ADS)

Brown, E.; Lesher, C. E.

2014-12-01

The compositions and volumes of basalts erupted at the earth's surface are a function of mantle temperature, mantle composition, and the rate at which the mantle upwells through the melting zone. Thus, basaltic magmatism has long been used to probe the thermal and physiochemical state of the earth's mantle. Great insight has been gained into the mantle beneath the global spreading ridge system, where the mantle source is assumed to be homogeneous peridotite that upwells passively [1]. However, it is now recognized that many basalt source regions are lithologically heterogeneous (i.e. containing recycled lithospheric material ranging from harzburgite to pyroxenite) and upwell at rates in excess of those governed by plate separation. To account for these complexities, we have developed a forward melting model for lithologically heterogeneous mantle that incorporates thermodynamically and experimentally constrained melting functions for a range of peridotite and pyroxenite lithologies. The model is unique because it quantifies mantle upwelling rates based on the net buoyancy of the source, thus providing a means for linking basalt compositions/volumes to mantle flow while accounting for source heterogeneity. We apply the model to investigate the mantle properties governing magmatism along different rift segments in Iceland, where lithologic heterogeneity and variable upwelling rates have been inferred through geochemical means [2,3]. Using constraints from seismically determined crustal thicknesses and recent estimates of the proportion of pyroxenite-derived melt contributing to Icelandic basalt compositions [4,5], we show that mantle sources beneath Iceland have excess potential temperatures >85 °C, contain <7% pyroxenite, and maximum upwelling rates ~14 times the passive rate. Our modeling highlights the dominant role of elevated mantle temperature and enhanced upwelling for high productivity magmatism in Iceland, and a subordinate role for mantle heterogeneity

Inside the volcano: The how and why of Thrihnukagigur volcano, Iceland

NASA Astrophysics Data System (ADS)

LaFemina, Peter; Hudak, Michael; Feineman, Maureen; Geirsson, Halldor; Normandeau, Jim; Furman, Tanya

2015-04-01

The Thrihnukagigur volcano, located in the Brennisteinsfjöll fissure swarm on the Reykjanes Peninsula, Iceland, offers a unique exposure of the upper magmatic plumbing system of a monogenetic volcano. The volcano formed during a dike-fed strombolian eruption ~3500 BP with flow-back leaving an evacuated conduit, elongated parallel to the regional maximum horizontal stress. At least two vents were formed above the dike, as well as several small hornitos south-southwest of the main vent. In addition to the evacuated conduit, a cave exists 120 m below the vent. The cave exposes stacked lava flows and a buried cinder cone. The unconsolidated tephra of the cone is cross-cut by a NNE-trending dike, which runs across the ceiling of this cave to the vent that produced lava and tephra during the ~3500 BP fissure eruption. We present geochemical, petrologic and geologic observations, including a high-resolution three-dimensional scan of the system that indicate the dike intersected, eroded and assimilated unconsolidated tephra from the buried cinder cone, thus excavating a region along the dike, allowing for future slumping and cave formation. Two petrographically distinct populations of plagioclase phenocrysts are present in the system: a population of smaller (maximum length 1 mm) acicular phenocrysts and a population of larger (maximum length 10 mm) tabular phenocrysts that is commonly broken and displays disequilibrium sieve textures. The acicular plagioclase crystals are present in the dike and lavas while the tabular crystals are in these units and the buried tephra. An intrusion that appears not to have interacted with the tephra has only acicular plagioclase. This suggests that a magma crystallizing a single acicular population of plagioclase intruded the cinder cone and rapidly assimilated the tephra, incorporating the tabular population of phenocrysts from the cone. Petrographic thin-sections of lavas sampled near the vent show undigested fragments of tephra from

Seasonal cross-shelf distribution of major zooplankton taxa on the northern Gulf of Alaska shelf relative to water mass properties, species depth preferences and vertical migration behavior

NASA Astrophysics Data System (ADS)

Coyle, Kenneth O.; Pinchuk, Alexei I.

2005-01-01

The cross-shelf distribution of major zooplankton species was examined on the northern Gulf of Alaska (GOA) shelf during the production season for four years, between October 1997 and October 2001. The zooplankton community on the northern GOA shelf consisted of oceanic and neritic species of the North Pacific subarctic species complex. Cross-shelf distribution of the major zooplankton species was influenced by their depth preferences, vertical migration behavior, salinity-temperature preferences, and by cross-shelf water-mass distribution and movement. The neritic community, dominated by Pseudocalanus spp., Metridia pacifica and Calanus marshallae, had highest abundances on the inner shelf, in the Alaska Coastal Current, and in the adjacent fjords in late spring and early summer. The oceanic community, which contained primarily Neocalanus cristatus and Eucalanus bungii, was observed in the Alaskan Stream and adjacent waters near the shelf break. A mid-shelf transition zone contained a mixture of oceanic and neritic species. Prince William Sound (PWS) contained a unique species complex of large mesopelagic copepods, amphipods and shrimp. Neocalanus flemingeri and Oithona similis were abundant in all four regions during spring and early summer. The transition zone commonly crossed much of the shelf between the shelf break and the ACC, but satellite images and CTD data indicate that occasionally a narrow shelf-break front can form, in which case distinct zooplankton species groups are observed on either side of the front. Satellite data also revealed numerous large and small eddies, which probably contribute to cross-shelf mixing in the transition zone.

Iceberg B-15, Ross Ice Shelf, Antarctica

NASA Technical Reports Server (NTRS)

2002-01-01

Iceberg B-15 broke from the Ross Ice Shelf in Antarctica in late March. Among the largest ever observed, the new iceberg is approximately 170 miles long x 25 miles wide. Its 4,250 square-mile area is nearly as large as the state of Connecticut. The iceberg was formed from glacial ice moving off the Antarctic continent and calved along pre-existing cracks in the Ross Ice Shelf near Roosevelt Island. The calving of the iceberg essentially moves the northern boundary of the ice shelf about 25 miles to the south, a loss that would normally take the ice shelf as long as 50-100 years to replace. This infrared image was acquired by the DMSP (Defense Meteorological Satellite Program) F-13 satellite on April 13, 2000. For more images see Antarctic Meteorological Research Center Image courtesy of the University of Wisconsin - Madison, Space Science and Engineering Center, Antarctic Meteorological Research Center

Bathymetry and acoustic backscatter of the mid and outer continental shelf, head of De Soto Canyon, northeastern Gulf of Mexico: data, images, and GIS

USGS Publications Warehouse

Gardner, James V.; Hughes-Clarke, John E.; Mayer, Larry A.; Dartnell, Peter

2003-01-01

The mid to outer continental shelf off Mississippi-Alabama and off northwest Florida were the focus of U.S. Geological Survey (USGS) multibeam echosounder (MBES) mapping cruises in 2000 and 2001, respectively. These areas were mapped to investigate the extent of "deep-water reefs" first suggested by Ludwig and Walton (1957). The reefs off Mississippi and Alabama were initially described in water depths of 60 to 120 m (Ludwig and Walton, 1957) but the 2000 mapping found reef and hardgrounds to be much more extensive than previously thought (Gardner et al., 2001). The persistent trend of reef-like features along the outer shelf of Mississippi-Alabama suggested the trend might continue along the northwest Florida mid and outer shelf so a MBES-mapping effort was mounted in 2001 to test this suggestion. It is critical to determine the accurate location, geomorphology, and types of the ridges and reefs that occur in this region to understand the Quaternary history of the area and to assess their importance as benthic habitats for fisheries. The area known as the "Head of De Soto Canyon" is the large unmapped region between the 2000 and 2001 mapped areas. It was unknown whether the reefs of the Mississippi-Alabama shelf continue eastward into the head of De Soto Canyon and connect with the ridges and reefs mapped on the northwest Florida outer shelf. The existence of carbonate-cemented Quaternary to Holocene sandstones along the western wall of the head of De Soto Canyon (Shipp and Hopkins, 1978; Benson et al., 1997; W.W. Schroeder, personal commun., 2002) is of interest because of the potential benthic habitats they may represent. In the summer of 2002, the USGS, in cooperation with Minerals Management Service (MMS), the University of New Hampshire, and the University of New Brunswick, conducted a MBES survey of the Head of De Soto Canyon Region connecting the 2000 and 2001 mapped regions.

Inclusion, Exclusion and the Queering of Spaces in Two Icelandic Upper Secondary Schools

ERIC Educational Resources Information Center

Kjaran, Jón Ingvar; Jóhannesson, Ingólfur Ásgeir

2015-01-01

The concept of space is gaining increased attention in studies of sexuality and gender, not least those focusing on heterosexism and heteronormativity. Such studies have demonstrated that space is sexualised, gendered and actively produced. In this article, we present the findings from an ethnographic study of two Icelandic upper secondary…

Mean Lagrangian drift in continental shelf waves

NASA Astrophysics Data System (ADS)

Drivdal, M.; Weber, J. E. H.

2012-04-01

The time- and depth-averaged mean drift induced by barotropic continental shelf waves (CSW's) is studied theoretically for idealized shelf topography by calculating the mean volume fluxes to second order in wave amplitude. The waves suffer weak spatial damping due to bottom friction, which leads to radiation stress forcing of the mean fluxes. In terms of the total wave energy density E¯ over the shelf region, the radiation stress tensor component S¯11 for CSW's is found to be different from that of shallow water surface waves in a non-rotating ocean. For CSW's, the ratio ¯S11/¯E depends strongly on the wave number. The mean Lagrangian flow forced by the radiation stress can be subdivided into a Stokes drift and a mean Eulerian drift current. The magnitude of the latter depends on the ratio between the radiation stress and the bottom stress acting on the mean flow. When the effect of bottom friction acts equally strong on the waves and the mean current, calculations for short CSW's show that the Stokes drift and the friction-dependent wave-induced mean Eulerian current varies approximately in anti-phase over the shelf, and that the latter is numerically the largest. For long CSW's they are approximately in phase. In both cases the mean Lagrangian current, which is responsible for the net particle drift, has its largest numerical value at the coast on the shallow part of the shelf. Enhancing the effect of bottom friction on the Eulerian mean flow, results in a general current speed reduction, as well as a change in spatial structure for long waves. Applying realistic physical parameters for the continental shelf west of Norway, calculations yield along-shelf mean drift velocities for short CSW's that may be important for the transport of biological material, neutral tracers, and underwater plumes of dissolved oil from deep water drilling accidents.

Calving and rifting on McMurdo Ice Shelf, Antarctica

NASA Astrophysics Data System (ADS)

Banwell, Alison; Willis, Ian; MacAyeal, Douglas; Goodsell, Becky; Macdonald, Grant; Mayer, David; Powell, Anthony

2017-04-01

On March 2, 2016, a series of small en échelon tabular icebergs calved from the seaward front of the McMurdo Ice Shelf, and a previously inactive ice-shelf rift suddenly widened and propagated by 3km, 25% of its previous length, setting the stage for future calving of an approximately 8 km2 segment of the ice shelf. Immediately prior to these events, perhaps within 24 hours, all remaining land-fast sea ice buttressing the ice shelf broke up and drifted away. The events were witnessed by time-lapse cameras at nearby Scott Base giving a unique opportunity to document the timing of the events and conditions leading up to them. In addition, the events can be put into context using nearby seismic and automatic weather station data, satellite imagery, and ground observation made 8 months later. Although the observations cannot be used definitively to identify the exact trigger of calving and rifting, the seismic records reveal superimposed sets of long-period (>10 s) sea swell, propagating into McMurdo Sound from distant storm sources in the Pacific Ocean, at the time of, and immediately prior to, the break-up of sea ice and associated ice shelf calving and rifting. This conspicuous presence suggests that sea swell should be studied further as a proximal cause of ice-shelf calving and rifting; if proven, it suggests that ice-shelf stability is tele-connected with far-field storm conditions at lower latitudes, adding a global dimension to the physics of potential ice-shelf breakup.

Downslope flow across the Ross Sea shelf break (Antarctica)

NASA Astrophysics Data System (ADS)

Bergamasco, A.; Budillon, G.; Carniel, S.; Defendi, V.; Meloni, R.; Paschini, E.; Sclavo, M.; Spezie, G.

2003-12-01

The analysis of some high-resolution hydrological data sets acquired during the 1997, 1998, 2001 and 2003 austral summers across the Ross Sea continental shelf break are here presented. The main focus of these cruises carried out in the framework of the Italian National Antarctic Program was the investigation of the downslope flow of the dense waters originated inside the Ross Sea. Such dense waters, flow near the bottom and, reaching the continental shelf break, ventilate the deep ocean. Two Antarctic continental shelf mechanisms can originate dense and deep waters. The former mechanism involves the formation, along the Victoria Land coasts, of a dense and saline water mass, the High Salinity Shelf Water (HSSW). The HSSW formation is linked to the rejection of salt into the water column as sea ice freezes, especially during winter, in the polynya areas, where the ice is continuously pushed offshore by the strong katabatic winds. The latter one is responsible of the formation of a supercold water mass, the Ice Shelf Water (ISW). The salt supplied by the HSSW recirculated below the Ross Ice Shelf, the latent heat of melting and the heat sink provided by the Ross Ice Shelf give rise to plumes of ISW, characterized by temperatures below the sea-surface freezing point. The dense shelf waters migrate to the continental shelf-break, spill over the shelf edge and descend the continental slope as a shelf-break gravity current, subject to friction and possibly enhanced by topographic channelling. Friction, in particular, breaks the constraint of potential vorticity conservation, counteracting the geostrophic tendency for along slope flow. The density-driven downslope motion or cascading entrains ambient water, namely the lower layer of the CDW, reaches a depth where density is the same and spreads off-slope. In fact, the cascading event is inhibited by friction without entrainment. The downslope processes are important for the ocean and climate system because they play a

Models of Deformation of Uppermost Oceanic Lithosphere: Comparison of Crustal Flexure in the Blönduós Area, Northern Iceland, and Structure of East Pacific Rise Crust at Hess Deep

NASA Astrophysics Data System (ADS)

Horst, A. J.; Karson, J. A.; Varga, R. J.; Gee, J. S.

2007-12-01

Models of the internal structure of oceanic crust have been constructed from studies of ophiolites and from more recent observations of tectonic windows into the upper crust. Spreading rate and/or magma supply are the central variables that control ridge processes and the ultimate architecture of ocean crust. In addition to ophiolites, Iceland also provides an important analog to study mid-ocean ridge processes and structure. Flexure zones in Iceland characterize the structure of Tertiary-Recent lava flows, and are areas wherein lavas dip regionally inward toward the axis of one of several ~N/S-trending rift zones. These rift zones are interpreted to represent fossil spreading centers which were abandoned during a series of eastward-directed ridge jumps. In the Hildará area, north-central Iceland, the eastern side of a regional flexure is characterized by westward-dipping lavas, approximately 6-8 Ma, which are cut by east-dipping normal faults and dikes. The upper-crustal structure within this flexure zone from slow spread (~20 mm/yr) crust exhibits remarkable similarities to the structure of the upper crust created at a fast-spreading (110 mm/yr) segment of the East Pacific Rise (EPR) observed at Hess Deep. In this modern ocean setting, ~1 Ma crust is characterized by west-dipping lavas above consistently east-dipping (away from the EPR) dikes and dike-subparallel fault zones. In both locations, paleomagnetic and structural data indicate that west-dipping lavas and east-dipping dikes result from tectonic rotations. In addition, cross-cutting dike relationships demonstrate that dike intrusion occurred both during and after normal fault- related tilting. These data indicate that fault-controlled tilting was initiated within the narrow neovolcanic zone of the ridge and is not associated with off-axis processes. Lavas at magmatically robust ridges commonly flow away from elevated ridge-crests. Measurement of anisotropy of magnetic susceptibility (AMS) of the lavas

Cyclonic entrainment of preconditioned shelf waters into a frontal eddy

NASA Astrophysics Data System (ADS)

Everett, J. D.; Macdonald, H.; Baird, M. E.; Humphries, J.; Roughan, M.; Suthers, I. M.

2015-02-01

The volume transport of nutrient-rich continental shelf water into a cyclonic frontal eddy (entrainment) was examined from satellite observations, a Slocum glider and numerical simulation outputs. Within the frontal eddy, parcels of water with temperature/salinity signatures of the continental shelf (18-19°C and >35.5, respectively) were recorded. The distribution of patches of shelf water observed within the eddy was consistent with the spiral pattern shown within the numerical simulations. A numerical dye tracer experiment showed that the surface waters (≤50 m depth) of the frontal eddy are almost entirely (≥95%) shelf waters. Particle tracking experiments showed that water was drawn into the eddy from over 4° of latitude (30-34.5°S). Consistent with the glider observations, the modeled particles entrained into the eddy sunk relative to their initial position. Particles released south of 33°S, where the waters are cooler and denser, sunk 34 m deeper than their release position. Distance to the shelf was a critical factor in determining the volume of shelf water entrained into the eddy. Entrainment reduced to 0.23 Sv when the eddy was furthest from the shelf, compared to 0.61 Sv when the eddy was within 10 km of the shelf. From a biological perspective, quantifying the entrainment of shelf water into frontal eddies is important, as it is thought to play a significant role in providing an offshore nursery habitat for coastally spawned larval fish.

The exchange of Kuroshio and East China Sea shelf water

NASA Astrophysics Data System (ADS)

Chern, Ching-Sheng; Wang, Joe; Wang, Dong-Ping

1990-09-01

A detailed hydrographic study of the East China Sea shelf edge north of Taiwan revealed an intense cold eddy on the shelf break and a large low-salinity filament at the slope. The cold eddy which is induced by the upwelling of the subsurface Kuroshio water has been repeatedly documented in previous studies. The filament which is made of the mixed shelf and subsurface Kuroshio water, on the other hand, has not been recognized before. The shelf edge upwelling appears to be associated with the sharp bending of the Kuroshio north of Taiwan, while the outpouring of shelf water appears to be associated with the northeasterly storms. Both the eddy and the filament consist of large fractions of the subsurface Kuroshio water, and they may be important to the salt and nutrient budget on the East China Sea shelf.

Early Deglaciation of Drangajökull, Vestfirðir, Iceland: Smaller than Present by 9.2 ka

NASA Astrophysics Data System (ADS)

Harning, D.; Geirsdottir, A.; Miller, G. H.; Zalzal, K.

2016-12-01

The Holocene histories of Iceland's largest ice caps suggest rapid early Holocene deglaciation and disappearance by 9 ka, other than possible small remnants of Vatnajökull. The least documented is Drangajökull, Vestfirðir, NW Iceland, where our team has been working since 2010. A recent study claims Drangajökull behaved differently than the other Iceland ice caps, deglaciating much later, and persisting through the Holocene Thermal Maximum (HTM). We test this postulate through a suite of sediment cores from threshold lakes both proximal and distal to the ice cap's contemporary margin. Distal lakes document rapid early Holocene deglaciation across the southern highland plateau, with the northern margin of the ice cap reaching a size comparable to Drangajökull's contemporary limit by 10.3 ka. A proximal lake to the north records a transient readvance at 9.6 ka, likely in association with meltwater pulses from the disintegrating Laurentide Ice Sheet (LIS). Two other southeastern proximal lakes, whose catchments extend well beneath the modern ice cap, demonstrate that Drangajökull was already smaller than present before 9.2 ka. Supporting evidence for local early Holocene warmth is derived from biological summer temperature proxies in a lake record, with age control (tephra/14C) demonstrating continuous sediment accumulation from 10.3 ka to present. Peak warmth (HTM) inferred from elevated algal productivity occurred between 8.9 and 7.2 ka. The record of terrestrial warmth closely aligns with regional SST and precipitation records that together with lake sediment characteristics provide firm evidence that Drangajökull responded similarly to Iceland's other large ice caps. Drangajökull was smaller than its contemporary margin before 9.2 ka, and likely disappeared entirely during the warmer and drier summers between 9 and 7 ka, reforming in the Late Holocene.

The Effects of Habitat Type and Volcanic Eruptions on the Breeding Demography of Icelandic Whimbrels Numenius phaeopus.

PubMed

Katrínardóttir, Borgný; Alves, José A; Sigurjónsdóttir, Hrefna; Hersteinsson, Páll; Gunnarsson, Tómas G

2015-01-01

Distinct preference of species for habitats is most often driven by long term differences in demographic rates between habitats. Estimating variation in those rates is key for developing successful conservation strategies. Stochastic events can interact with underlying variation in habitat quality in regulating demography but the opportunities to explore such interactions are rare. Whimbrels in Iceland show a strong preference for sparsely vegetated riverplains. Such habitats in Iceland face various threats, e.g., climate change, river regulation and spread of alien plant species. In this study we compared demographic parameters of breeding Whimbrels between riverplains and other habitats before, during and after volcanic eruption events to estimate the importance of the habitats for the species and the effect of ash deposit on breeding success. We found that an estimated minimum of 23% of the Icelandic population of Whimbrels and c. 10% of the world population of the species breed in riverplain habitats in Iceland. Whimbrels bred consistently at much higher densities in riverplain habitats than in other habitats and riverplains also had higher densities of pairs with fledglings although the proportion of successful breeders was similar between habitats. Predation by livestock may have had a considerable negative effect on breeding success on our study sites. Breeding was negatively affected by the volcanic activity, probably through the effects of ash on the invertebrate food supply, with breeding success being gradually worse closer to the eruption. Breeding success was equally affected by volcanism across habitats which differed in underlying habitat quality. This study gives an example of how populations can be regulated by factors which operate at different spatial scales, such as local variation in habitat quality and stochastic events which impact larger areas.

Foehn and temperature-based melt patterns over the Larsen C Ice Shelf as simulated by the MAR regional climate model

NASA Astrophysics Data System (ADS)

Datta, R.; Tedesco, M.; Agosta, C.; Fettweis, X.; Kuipers Munneke, P.; van den Broeke, M. R.

2017-12-01

Surface melting has been implicated in the collapse of Antarctic Peninsula ice shelves, most dramatically in the Larsen A (1995) and Larsen B (2002) ice shelves. In July of this year, a rift in the remaining Larsen C ice shelf broke away one of the largest icebergs ever recorded. Ice-shelf retreat is likely related to strong atmospheric warming in this area, by means of hydrofracturing and possibly by the warming atmosphere itself. According the hydrofracture mechanism, meltwater produced during anomalously warm summers infiltrates and deepens pre-existent crevasses, leading to the eventual break-up of the ice shelf. In addition to region-wide warming, melting in the East Antarctic Peninsula can be caused by frequent intrusions of westerly foehn winds. The remaining Larsen C ice shelf, as well as glaciers previously feeding to the former Larsen B ice shelf, are therefore vulnerable to both (a) the atmospheric circulation patterns that influence foehn wind frequency and intensity and (b) regional interannual temperature trends. We discuss spatial patterns of meltwater production in the northeast basin of the Antarctic Peninsula as modeled by the Modèle Atmosphérique Régionale (MAR) at a 10km resolution between 2001 and 2014. The timeseries associated with these patterns are used to identify interannual changes in the frequency of foehn-induced melt, and compare foehn-induced melting to melt associated with regional warming. Melt occurrence in MAR is evaluated against multiple satellite datasets and near-surface automatic weather station data from three sites. Finally, we discuss the seasonal depth to which meltwater percolates into the snowpack (as modeled by MAR) because of the potential influence of meltwater on both warming and densification of the ice shelf.

Shelf Circulation Induced by an Orographic Wind Jet

NASA Astrophysics Data System (ADS)

Ràfols, Laura; Grifoll, Manel; Jordà, Gabriel; Espino, Manuel; Sairouní, Abdel; Bravo, Manel

2017-10-01

The dynamical response to cross-shelf wind-jet episodes is investigated. The study area is located at the northern margin of the Ebro Shelf, in the Northwestern (NW) Mediterranean Sea, where episodes of strong northwesterly wind occur. In this case, the wind is channeled through the Ebro Valley and intensifies upon reaching the sea, resulting in a wind jet. The wind-jet response in terms of water circulation and vertical density structure is investigated using a numerical model. The numerical outputs agree with water current observations from a high-frequency radar. Additionally, temperature, sea level, and wind measurements are also used for the skill assessment of the model. For the wind-jet episodes, the numerical results show a well-defined two-layer circulation in the cross-shelf direction, with the surface currents in the direction of the wind. This pattern is consistent with sea level set-down due to the wind effect. The comparison of the vertical structure response for different episodes revealed that the increase of stratification leads to an onshore displacement of the transition from inner shelf to mid-shelf. In general, the cross-shelf momentum balance during a wind-jet episode exhibits a balance between the frictional terms and the pressure gradient in shallow waters, shifting to a balance between the Coriolis force and the wind stress terms in deeper waters.

Teleseismic Earthquake Signals Observed on an Ice Shelf

NASA Astrophysics Data System (ADS)

Baker, M. G.; Aster, R. C.; Anthony, R. E.; Wiens, D.; Nyblade, A.; Bromirski, P. D.; Stephen, R. A.; Gerstoft, P.

2015-12-01

The West Antarctic Rift System (WARS) is one of Earth's largest continental extension zones. Study of the WARS is complicated by the presence of the West Antarctic Ice Sheet, the Ross Ice Shelf, and the Ross Sea. Recent deployments of broadband seismographs in the POLENET project have allowed passive seismic techniques, such as receiver function analysis and surface wave dispersion, to be widely utilized to infer crustal and mantle velocity structure across much of the WARS and West Antarctica. However, a large sector of the WARS lies beneath the Ross Ice Shelf. In late 2014, 34 broadband seismographs were deployed atop the ice shelf to jointly study deep Earth structure and the dynamics of the ice shelf. Ice shelf conditions present strong challenges to broadband teleseismic imaging: 1) The presence of complicating signals in the microseism through long-period bands due to the influence of ocean gravity waves; 2) The strong velocity contrasts at the ice-water and water-sediment interfaces on either side of the water layer give rise to large amplitude reverberations; 3) The water layer screens S-waves or P-to-S phases originating from below the water layer. We present an initial analysis of the first teleseismic earthquake arrivals collected on the ice shelf at the end of the 2014 field season from a limited subset of these stations.

Glacigenic landforms and sediments of the Western Irish Shelf

NASA Astrophysics Data System (ADS)

McCarron, Stephen; Monteys, Xavier; Toms, Lee

2013-04-01

Vibrocoring of possible glacigenic landforms identified from high resolution bathymetric coverage of the Irish Shelf by the Irish National Seabed Survey (INSS) has provided several clusters of short (<3m) cores that, due to a regional post-glacial erosional event, comprise last glacial age stratigraphies. In addition, new shallow seismic data and sedimentological information from across the Western Irish Shelf provide new insights into aspects of the nature, timing and pattern of shelf occupation by grounded lobate extensions of the last Irish Ice Sheet. Restricted chronological control of deglacial sequences in several cores indicates that northern parts of the western mid-shelf (south of a prominent outer Donegal Bay ridge) were ice free by ~24 ka B.P., and that ice had also probably retreated from outer shelf positions (as far west as the Porcupine Bank) at or before this time.

Lung cancer mortality trends in 36 European countries: secular trends and birth cohort patterns by sex and region 1970-2007.

PubMed

Bray, Freddie Ian; Weiderpass, Elisabete

2010-03-15

Smoking is a major contributor to all-cause mortality in Europe and accounts for one-fifth of the cancer-related deaths. Monitoring the tobacco epidemic via an analysis of lung cancer trends is essential in helping countries arrest the effects of tobacco epidemic in the region. The study aims to provide a comprehensive and up-to-date overview of the temporal patterns of lung cancer mortality in Europe, emphasizing country- and sex-specific differences. National lung cancer mortality data were extracted from the WHO mortality databank by age, sex, year of death (1970-2007) for 36 countries in Europe. Trends in lung cancer mortality in men have tended to decrease in many European countries during the last two decades, particularly in North and Western Europe. Among women, mortality rates are still increasing in many countries, although in a few populations, rates are beginning to stabilize, notably in the high-risk countries within Eastern Europe (Hungary, Poland and the Czech Republic), and in Northern Europe (Denmark, Iceland and the United Kingdom). Men and women are clearly in very different phases of the smoking epidemic, and, as reflected in the mortality rates by birth cohort, the stage varies widely by country within each European region. That lung cancer mortality trends in men are on a downwards path in most European countries while female rates continue to rise, points to an urgent need for national and European prevention strategies that target tobacco cessation and prevention among European women.

Novel decomposition products of chlorophyll- a in continental shelf (Louisiana shelf) sediments: formation and transformation of carotenol chlorin esters

NASA Astrophysics Data System (ADS)

Chen, Nianhong; Bianchi, Thomas S.; Bland, John M.

2003-06-01

In April 2000, we collected box cores from five stations along a cross-shelf transect on the Louisiana (LA) continental shelf. Novel esters of carotenols and chlorins (carotenoid chlorin esters, CCEs), which are highly specific grazing markers, were identified in surface and deep sediments (>10 cm) from the LA shelf. Chlorophyll- a inventory indicated that CCEs are one of the major decay products of chlorophyll- a in shelf sediments. Abundances of total CCEs (9-18%) in surface sediments along the cross-shelf transect were comparable to the abundance of pheophytin- a, pyropheophytin- a, and total steryl chlorin esters (SCEs). Prior work has identified four CCEs which have dehydrated fucoxanthin/fucoxanthinol as a substitute alcohol of phytol. We report on four newly identified CCEs associated with nondehydrated fuxocanthin/fucoxanthinol esterified to (pyro)pheophorbide- a. These nondehydrated CCEs were generally present in lower concentrations than their dehydrated counterparts, but were detectable by atmospheric pressure chemical ionization (APCI) mass spectrometry coupled with high-performance liquid chromatography (HPLC). We attributed differences between this study and previous work to the time allowed for predepositional decay and grazing processes to occur. The rapid sedimentation of CCEs in the shallow water column (ca. 10 m) on the LA shelf allowed for effective burial of all CCEs compared to the deeper water column regions sampled by previous work. This speculation is supported by the fact that the concentrations of CCEs with nondehydrated fucoxanthin/fucoxanthinol were extremely low in sediments from the site on the outer LA shelf with a deeper (253 m) water column. We also tentatively identified an additional CCE and its isomer as fucoxanthinol didehydrate pyropheophorbide- a ester. We suggest that the formation and transformation of CCEs are primarily controlled by the following three biologically mediated reactions: demethoxycarbonylation, dehydration

A dense, intersecting array of normal faults on the outer shelf off Southern Costa Rica, associated with subducting Quepos ridge

NASA Astrophysics Data System (ADS)

Silver, E. A.; Kluesner, J. W.; Gibson, J. C.; Bangs, N. L.; McIntosh, K. D.; von Huene, R.; Orange, D.; Ranero, C. R.

2012-12-01

Use of narrow, fixed swath multibeam data with high sounding densities has allowed order of magnitude improvement in image resolution with EM122 multibeam and backscatter data, as part of a 3D seismic study west of the Osa Peninsula. On the outer shelf, along the projection of the subducting Quepos Ridge, we mapped a dense array of faults cutting an arcuate, well-layered set of outcropping beds in the backscatter imagery (mosaicked at 2 m), with roughly N-S and E-W trends. The N-S trends dominate, and show inconsistent offsets, implying that the faults are normal and not strike-slip. The faults also show normal displacement in the 3D seismic data, consistent with the surface interpretation. The outcropping beds (of late Pleistocene age, based on Expedition 334 drilling), may have been truncated during the late Pleistocene low sea-level stand. The outermost shelf (edged by arcuate bathymetric contours) does not show these folded beds, as it was below wave base and buried by a thin sediment layer. However, narrow lines of small pockmarks and mounds follow the fault trends exactly, indicating that fluid flow through the faults is expressed at the surface, including a gas plume that extends to the sea-surface. The almost unprecedented increase in resolution of the EM122 data allows us to infer that the N-S, E-W grid of faults overlying the NE-trending Quepos Ridge projection (and NE directed subduction) formed by extensional arching above the ridge, not by collisional slip lines at a rigid indenter (as proposed earlier based on sandbox models). The extensional fault pattern also facilitates fluid and gas flow through the sedimentary section.

From Isolation and Stagnation to "Modern" Mathematics in Iceland: A Reform or Confusion?

ERIC Educational Resources Information Center

Bjarnadottir, Kristin

2006-01-01

At the beginning of the twentieth century, Iceland was under Danish rule. It was isolated in the middle of the North Atlantic, enjoying only little cultural exchange with other countries. A strong tradition of literacy and nurturing of literature flourished there, while knowledge in mathematics, natural sciences and technical matters was mainly…

Design and Craft Education in Iceland, Pedagogical Background and Development: A Literature Review

ERIC Educational Resources Information Center

Olafsson, Brynjar; Thorsteinsson, Gisli

2009-01-01

Sloyd pedagogy was introduced towards the close of the 18th century to Icelandic educators. Subsequently craft was established as a specific subject aimed at general education. In the beginning craft was called "school industry," to distinguish it from "home industry" whose aim was to help homes to be self-sufficient for…

Eruption at Bardarbunga, Iceland

NASA Image and Video Library

2015-01-27

The main caldera of Bardarbunga volcano is tucked beneath Iceland’s largest glacier, Vatnajökull. Beginning in August, 2014, red-hot basaltic lava originating from Bardarbunga has been pouring from fissures just north of Vatnajökull, creating the massive Holuhraun lava field. As of January 6, 2015, the Holuhraun lava field had spread across more than 84 square kilometers (32 square miles), making it larger than the island of Manhattan. Holuhraun is Iceland’s largest basaltic lava flow since the Laki eruption in 1783–84, an event that killed 20 percent of the island’s population. Scientists from the University of Iceland’s Institute of Earth Sciences have estimated the thickness of the lava field based on data from surveillance flights. On average, the eastern part was about 10 meters (33 feet) thick, the center was 12 meters, and the western part was 14 meters. Their preliminary analysis put the volume of lava at 1.1 cubic kilometers, enough for the eruption to be considered a flood basalt. While Holuhraun continues to spew copious amounts of lava and sulfur dioxide, some observations suggest the eruption may be slowing down. As Edinburgh University volcanologist John Stevenson noted on his blog, Icelandic scientists have shown that the sinking (subsidence) of the caldera has declined from 80 centimeters (31 inches) to 25 centimeters per day—a sign that less magma is moving toward the surface. In addition, magnitude 5 or higher earthquakes that used to occur daily are now happening about once a week. Meanwhile, satellite observations of heat flux show a decline from more than 20 gigawatts in early September to fewer than 5 gigawatts by the end of November. As reported by Volcano Discovery, one bold scientist has even suggested that it is reasonable to forecast that the eruption may be over by March, 2015. The Moderate Resolution Imaging Spectrometer (MODIS) aboard NASA’s Aqua satellite flew over Iceland on January 18, 2015 and captured a false

West Florida Shelf Response to Hurricane Irma

NASA Astrophysics Data System (ADS)

Liu, Y.; Weisberg, R. H.; Chen, J.; Merz, C. R.; Law, J.; Zheng, L.

2017-12-01

Hurricane Irma impacted the west Florida continental shelf (WFS) as it transited the state of Florida during September 10-12, 2017, making landfall first at Cudjoe Key and then again at Naples, as a Category 2 hurricane. The WFS response to Hurricane Irma is analyzed using a combination of in situ observations and numerical model simulations. The observations include water column velocity (by Acoustic Doppler Current Profilers), sea surface temperature and meteorological records from three moorings on the shelf, surface currents by high-frequency radars, and coastal tide gauge records. The West Florida Coastal Ocean Model (WFCOM) employed downscales from the deep Gulf of Mexico, across the shelf and into the estuaries by nesting the unstructured grid FVCOM in the Gulf of Mexico HYCOM. Both the observations and the model simulations revealed strong upwelling and vertical mixing followed by downwelling as the storm passed by. This was accompanied by a rapid drop in sea surface temperature of approximately 4ºC and large decreases in sea level with associated negative surges, causing drying in the Florida Bay, Charlotte Harbor, Tampa Bay estuaries and the Big Bend region. The transport and exchange of water between the shelf and the estuaries and between the shelf and the Florida Keys reef track during the hurricane may have important implications for ecosystem studies within the region.

Uncovering the glacial history of the Irish continental shelf (Invited)

NASA Astrophysics Data System (ADS)

Dunlop, P.; Benetti, S.; OCofaigh, C.

2013-12-01

In 1999 the Irish Government initiated a €32 million survey of its territorial waters known as the Irish National Seabed Survey (INSS). The INSS is amongst the largest marine mapping programmes ever undertaken anywhere in the world and provides high-resolution multibeam, backscatter and seismic data of the seabed around Ireland. These data have been used to provide the first clear evidence for extensive glaciation of the continental shelf west and northwest of Ireland. Streamlined drumlins on the mid to outer shelf record former offshore-directed ice flow towards the shelf edge and show that the ice sheet was grounded in a zone of confluence where ice flowing onto the shelf from northwest Ireland merged with ice flowing across the Malin Shelf from southwest Scotland. The major glacial features on the shelf are well developed nested arcuate moraine systems that mark the position of the ice sheet margin and confirm that the former British Irish Ice Sheet was grounded as far as the shelf edge around 100 km offshore of west Donegal at the last glacial maximum. Distal to the moraines, on the outermost shelf, prominent zones of iceberg plough marks give way to the Barra/Donegal fan and a well developed system of gullies and canyons which incise the continental slope. Since 2008 several scientific cruises have retrieved cores from the shelf and slope to help build a more detailed understanding of glacial events in this region. This presentation will provide an overview of the glacial history of the Irish shelf and will discuss ongoing research programmes that are building on the initial research findings to produce a better understanding of the nature and timing of ice sheet events in this region.

Adolescent substance use, parental monitoring, and leisure-time activities: 12-year outcomes of primary prevention in Iceland.

PubMed

Kristjansson, Alfgeir Logi; James, Jack E; Allegrante, John P; Sigfusdottir, Inga Dora; Helgason, Asgeir R

2010-08-01

To examine 12-year changes in alcohol use and cigarette smoking in response to community-based prevention activities among Icelandic adolescents. This study used a quasi-experimental, non-randomized control group design to compare outcomes in 4 Icelandic communities (n=3117) that participated in community-based substance use prevention activities designed to increase levels of parental monitoring and adolescent engagement in healthy leisure-time activities and a matched group of 7 comparison communities (n=1,907). Annual, nationwide, population-based cross-sectional surveys of the prevalence of adolescent substance use were conducted among cohorts of Icelandic adolescents, aged 14-15 years (N=5,024), in all communities from 1997 to 2009. Parental monitoring and adolescent participation in organized sports increased in communities that adopted the intervention program compared to communities that did not, whereas unmonitored idle hours and attendance at unsupervised parties decreased. Over time, alcohol use (OR=0.89, 95% CI 0.82, 0.98, p=0.012) and being intoxicated during the last 30 days (OR=0.86, 95% CI 0.78, 0.96, p=0.004) decreased more in the intervention than control communities. Community-based prevention designed to strengthen parental monitoring and participation in organized sports may confer some protection against adolescent substance use. Copyright 2010 Elsevier Inc. All rights reserved.

Polyhalogenated compounds (PCBs, chlordanes, HCB and BFRs) in four polar bears (Ursus maritimus) that swam malnourished from East Greenland to Iceland.

PubMed

Vetter, Walter; Gall, Vanessa; Skírnisson, Karl

2015-11-15

Levels of organohalogen compounds (PCBs, chlordane, PBB 153, PBDEs, HCB) were determined in adipose tissue, liver, kidney and muscle of four polar bears which swam and/or drifted to Iceland in extremely malnourished condition. Since the colonization in the 9th century polar bears have been repeatedly observed in Iceland. However, in recent years three of the animals have clearly left their natural habitat in poor condition in May or June, i.e. at the end of the major feeding season. The fourth bear is believed to have drifted with melting ice to North-Eastern Iceland in mid-winter. The concentrations of the POPs were within the range or higher than the typical concentrations measured in polar bears from the East Greenland population. In addition to the targeted compounds, we tentatively detected Dechlorane 602 and its potential hydrodechlorinated Cl11-metabolite in all samples. Moreover, a polychlorinated compound which partly co-eluted with PCB 209 was detected in all liver samples but not in adipose tissue, kidney or muscle. The mass spectrum of the potential metabolite did not allow determining its structure. Polar bears are good swimmers and can reach Iceland from the ice edge of East Greenland within a few days. Potential reasons for the swims are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Short-Term Variability on the Scotian Shelf

NASA Astrophysics Data System (ADS)

Greenan, B.; Petrie, B.; Harrison, G.; Oakey, N.; Strain, P.

2002-12-01

The traditional view of the production cycle on the continental shelf of Nova Scotia features a spring bloom followed by a period of low production and a less intense fall bloom. The annual cycle of primary productivity thus has a large, low frequency component. However, there is increasing evidence that the production cycle has significant variability on shorter time scales. Physical, chemical and biological variability on the Scotian Shelf is examined on a daily to weekly timescale. This is accomplished through the use of a newly developed mooring platform (SeaHorse) that uses surface wave energy to enable the instrument to climb down the mooring wire and then float upwards while sampling the water column. This provides bi-hourly profiles of temperature, salinity, pressure and chlorophyll at one location over month-long periods. Results from the three-week deployment in October 2000 indicate a subsurface chlorophyll maximum below the pycnocline during the first part of the time series. An event occurred in mid-October during which the temperature, salinity and density iso-surfaces rose approximately 25 m. During this event, a small bloom, with peak chlorophyll concentrations of about 2 mg m-3 and duration of several days, began as nutrients were brought into the upper part of the water column by upwelling-favorable winds. SeaWiFS ocean color satellite images were valuable in providing a spatial context for chlorophyll concentrations, however, the lack of temporal resolution due to poor quality images means that this data set provided limited information for short-term chlorophyll variability. Gradient Richardson Numbers were estimated for 2 m vertical bins using SeaHorse CTD data and nearby ADCP current measurements. A trend of decreasing Ri in the ocean mixed layer with increasing surface wind stress is suggested.

The effect of rider weight and additional weight in Icelandic horses in tölt: part II. Stride parameters responses.

PubMed

Gunnarsson, V; Stefánsdóttir, G J; Jansson, A; Roepstorff, L

2017-09-01

This study investigated the effects of rider weight in the BW ratio (BWR) range common for Icelandic horses (20% to 35%), on stride parameters in tölt in Icelandic horses. The kinematics of eight experienced Icelandic school horses were measured during an incremental exercise test using a high-speed camera (300 frames/s). Each horse performed five phases (642 m each) in tölt at a BWR between rider (including saddle) and horse starting at 20% (BWR20) and increasing to 25% (BWR25), 30% (BWR30), 35% (BWR35) and finally 20% (BWR20b) was repeated. One professional rider rode all horses and weight (lead) was added to saddle and rider as needed. For each phase, eight strides at speed of 5.5 m/s were analyzed for stride duration, stride frequency, stride length, duty factor (DF), lateral advanced placement, lateral advanced liftoff, unipedal support (UPS), bipedal support (BPS) and height of front leg action. Stride length became shorter (Y=2.73-0.004x; P0.05). In conclusion, increased BWR decreased stride length and increased DF proportionally to the same extent in all limbs, whereas BPS increased at the expense of decreased UPS. These changes can be expected to decrease tölt quality when subjectively evaluated according to the breeding goals for the Icelandic horse. However, beat, symmetry and height of front leg lifting were not affected by BWR.

Deciphering tectonic phases of the Amundsen Sea Embayment shelf, West Antarctica, from a magnetic anomaly grid

NASA Astrophysics Data System (ADS)

Gohl, Karsten; Denk, Astrid; Eagles, Graeme; Wobbe, Florian

2013-02-01

The Amundsen Sea Embayment (ASE), with Pine Island Bay (PIB) in the eastern embayment, is a key location to understanding tectonic processes of the Pacific margin of West Antarctica. PIB has for a long time been suggested to contain the crustal boundary between the Thurston Island block and the Marie Byrd Land block. Plate tectonic reconstructions have shown that the initial rifting and breakup of New Zealand from West Antarctica occurred between Chatham Rise and the eastern Marie Byrd Land at the ASE. Recent concepts have discussed the possibility of PIB being the site of one of the eastern branches of the West Antarctic Rift System (WARS). About 30,000 km of aeromagnetic data - collected opportunistically by ship-based helicopter flights - and tracks of ship-borne magnetics were recorded over the ASE shelf during two RV Polarstern expeditions in 2006 and 2010. Grid processing, Euler deconvolution and 2D modelling were applied for the analysis of magnetic anomaly patterns, identification of structural lineaments and characterisation of magnetic source bodies. The grid clearly outlines the boundary zone between the inner shelf with outcropping basement rocks and the sedimentary basins of the middle to outer shelf. Distinct zones of anomaly patterns and lineaments can be associated with at least three tectonic phases from (1) magmatic emplacement zones of Cretaceous rifting and breakup (100-85 Ma), to (2) a southern distributed plate boundary zone of the Bellingshausen Plate (80-61 Ma) and (3) activities of the WARS indicated by NNE-SSW trending lineaments (55-30 Ma?). The analysis and interpretation are also used for constraining the directions of some of the flow paths of past grounded ice streams across the shelf.

Mixing in seasonally stratified shelf seas: a shifting paradigm.

PubMed

Rippeth, Tom P

2005-12-15

Although continental shelf seas make up a relatively small fraction (ca 7%) of the world ocean's surface, they are thought to contribute significantly (20-50% of the total) to the open-ocean carbon dioxide storage through processes collectively known as the shelf sea pump. The global significance of these processes is determined by the vertical mixing, which drives the net CO(2) drawdown (which can occur only in stratified water). In this paper, we focus on identifying the processes that are responsible for mixing across the thermocline in seasonally stratified shelf seas. We present evidence that shear instability and internal wave breaking are largely responsible for thermocline mixing, a clear development from the first-order paradigm for the water column structure in continental shelf seas. The levels of dissipation observed are quantitatively consistent with the observed dissipation rates of the internal tide and near-inertial oscillations. It is perhaps because these processes make such a small contribution to the total energy dissipated in shelf seas that they are not well represented in current state-of-the-art numerical models of continental shelf seas. The results thus present a clear challenge to oceanographic models.

Ice-shelf Dynamics Near the Front of Filchner-Ronne Ice Shelf, Antarctica, Revealed by SAR Interferometry: Model/Interferogram Comparison

NASA Technical Reports Server (NTRS)

MacAyeal, D. R.; Rignot, E.; Hulbe, C. L.

1998-01-01

We compare Earth Remote Sensing (ERS) satellite synthetic-aperture radar (SAR) interferograms with artificial interferograms constructed using output of a finite-element ice-shelf flow model to study the dynamics of Filchner-Ronne Ice Shelf (FRIS) near Hemmen Ice Rise (HIR) where the iceberg-calving front itersects Berkener Island (BI).

Manifestations of Heterosexism in Icelandic Upper Secondary Schools and the Responses of LGBT Students

ERIC Educational Resources Information Center

Kjaran, Jón Ingvar; Jóhannesson, Ingólfur Ásgeir

2013-01-01

How does institutionalized heterosexism manifest itself in Icelandic upper secondary schools and how do lesbian, gay, bisexual, and transgender (LGBT) students respond to these manifestations? In addressing these questions, interviews were conducted with six current and former LGBT upper secondary school students, using queer theory and thematic…

Transport of Iceland-Scotland Overflow waters in the Deep Western Boundary Current along the Reykjanes Ridge

NASA Astrophysics Data System (ADS)

Johns, William; Houk, Adam; Koman, Greg; Zou, Sijia; Lozier, Susan

2017-04-01

Since 2014, an array of current meters deployed as part of the OSNAP trans-basin observing system has provided new measurements of the southward flow of Iceland-Scotland Overflow water (ISOW) along the eastern flank of the Reykjanes Ridge in the Iceland Basin. The location of the array, near 58-59°N, captures the ISOW Deep Western Boundary Current at the farthest downstream location in the Iceland Basin before significant amounts of ISOW can flow into the Irminger Basin through deep fractures in the Reykjanes Ridge. The transport of the ISOW DWBC at this location - based on the first two years of OSNAP observations (July 2014 to July 2016) - is 5.8 ± 0.9 Sv for σθ >27.8. Most of this transport is carried in a main branch of the DWBC along the upper ridge crest in depths from 1400-2200 m, while a secondary branch in depths of 2400-2700 m along the lower ridge crest carries about 1 Sv. The branching of the DWBC at this location is consistent with numerical model results and is caused by an upstream topographic plateau at mid-depths along the ridge crest. The T-S properties of the flow and backward trajectories computed from high-resolution FLAME and VIKING models confirm that the flow in both branches is derived from ISOW and its entrainment products. The transport of the ISOW plume varies over a considerable range, from about 2-10 Sv on weekly to monthly time scales (std. dev. = 2.4 Sv); however the mean currents from two individual year-long deployments are very similar and indicate a robust mean flow structure. The observed ISOW transport at this location is larger by almost 2 Sv than previous values obtained (mostly) farther north in the Iceland Basin, suggesting that additional entrainment into the ISOW plume occurs as it approaches the southern tip of the Reykjanes Ridge.

Before the 'Big Chill': Patterns of plant-insect associations from the Neogene of Iceland

NASA Astrophysics Data System (ADS)

Wappler, Torsten; Grímsson, Friðgeir

2016-07-01

Iceland is the only known terrestrial place in the subarctic North Atlantic providing a fairly continuous sedimentary and plant fossil record over the past 15 million years. While the basic palaeobotanical framework of this pattern has been well established during the last decade, less attention has been paid to the abundant insect traces on fossil leaves/leaflets. Here, we assess the diversity and frequency of insect herbivory on 4349 fossil angiosperm leaves/leaflets from six plant-bearing sedimentary formations exposed at 18 localities. By combining analyses of environmental factors, species interactions, ecology, biogeography, and the geological history, our results demonstrate how patterns of herbivory have changed over time in relation to temperature fluctuations that profoundly influenced levels of insect-mediated damage diversity and frequency. In addition, higher structural complexity, particularly the establishment of species-rich herb layer communities seems to have positively influenced the structure of insect communities in early late Miocene palaeoforests of Iceland.

[Extent and impact of the measles epidemics of 1846 and 1882 in Iceland].

PubMed

Gunnarsdottir, Sandra; Briem, Haraldur; Gottfredsson, Magnus

2014-04-01

Measles have increased in incidence in some parts of the developed world in the past 10-15 years. They can be fatal and lead to severe sequelae.Measles were infrequently introduced to Iceland in the 19th century and consequently, epidemics were few but associated with an extremely high mortality. The availability of 19th century church registries enables studies on the impact of measles on mortality. Historical accounts mention two major measles epidemics, starting mid-year 1846 and 1882. We analysed these two epidemics using contemporary historical sources, mainly original church registries. In the 1846 epidemic the data show a clear increase in mortality in June and reach a peak in July of 741 fatal cases total, a four-fold increase from expected baseline rate. The epidemic subsided in the ensuing five months. A cluster of measles was described in the eastern region of Iceland in 1869 but did not spread further. The epidemic of 1882 reached its peak in July, when 1084 individuals died, a five-fold increase from the expected rate. Excess mortality was highest in N-Isafjardarsysla county, 4,7 %, and none in A-Skaftafellssysla county where the illness was described 13 years previously. The highest numbers of fatal cases in the 1882 epidemic (64,6%) was among 0-4 year old children. The number of fatalities among women of child-bearing age was more than two-fold compared to men; the number of births 7-9 months following the 1882 peak dropped significantly by 50%. This study highlights the consequences of measles following introduction into a largely susceptible population and also documents the importance of herd immunity. Information can be identified on most individual fatalities during the 1846 and 1882 measles epidemics in Iceland.

Exploring the persistence of sorted bedforms on the inner-shelf of Wrightsville Beach, North Carolina

USGS Publications Warehouse

Gutierrez, Ben; Voulgaris, George; Thieler, E. Robert

2005-01-01

Geological studies offshore of Wrightsville Beach, North Carolina reveal subtle large-scale regions of coarse sand with gravel and shell hash (widths between 100 and 200 m and negative relief of ∼1 m) that trend obliquely to the coast. It was previously suggested that these regions serve as conduits for sand exchange between the shoreface and inner shelf during storm-associated downwelling. Consequently they were classified as rippled scour depressions. More recently, the role of alongshore flows and self-organization as a result of inhibited settling of fine sand has been discussed. In this study, 45 days of near-bed current measurements were analyzed using benthic boundary layer and sediment transport models to examine the role of along- and cross-shore flows in driving sediment transport at this site. The wind climate was found to be a dominant influence on near-bed flows. Six distinct sediment transport events were recognized. During these events, sediment transport models show that bedload transport is directed mainly in the cross-shore direction, while suspended sediments are directed alongshore to the southwest. Current observations during these sediment transport events provide no evidence of cross-shore sediment transport caused by steady downwelling currents. Instead, benthic boundary layer model results are used to show that differences in bed roughness between the coarse areas of the seabed within the “rippled scour depressions” and the finer areas of the inner shelf are more pronounced during increasingly energetic wave and current conditions. The enhanced difference in roughness results in increased turbulence intensities over coarse regions inhibiting the deposition of the fine sand that is resuspended over the shelf during these events relative to finer areas over the shelf. Findings from this study contribute to explaining the observed long-term persistence of these features.

Ocean-Forced Ice-Shelf Thinning in a Synchronously Coupled Ice-Ocean Model

NASA Astrophysics Data System (ADS)

Jordan, James R.; Holland, Paul R.; Goldberg, Dan; Snow, Kate; Arthern, Robert; Campin, Jean-Michel; Heimbach, Patrick; Jenkins, Adrian

2018-02-01

The first fully synchronous, coupled ice shelf-ocean model with a fixed grounding line and imposed upstream ice velocity has been developed using the MITgcm (Massachusetts Institute of Technology general circulation model). Unlike previous, asynchronous, approaches to coupled modeling our approach is fully conservative of heat, salt, and mass. Synchronous coupling is achieved by continuously updating the ice-shelf thickness on the ocean time step. By simulating an idealized, warm-water ice shelf we show how raising the pycnocline leads to a reduction in both ice-shelf mass and back stress, and hence buttressing. Coupled runs show the formation of a western boundary channel in the ice-shelf base due to increased melting on the western boundary due to Coriolis enhanced flow. Eastern boundary ice thickening is also observed. This is not the case when using a simple depth-dependent parameterized melt, as the ice shelf has relatively thinner sides and a thicker central "bulge" for a given ice-shelf mass. Ice-shelf geometry arising from the parameterized melt rate tends to underestimate backstress (and therefore buttressing) for a given ice-shelf mass due to a thinner ice shelf at the boundaries when compared to coupled model simulations.