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Sample records for west greenland waters

  1. Ecosystem variability in west Greenland waters

    DEFF Research Database (Denmark)

    Buch, E.; Pedersen, Søren Anker; Ribergaard, M. H.

    2004-01-01

    A review of the climate conditions off West Greenland during the past 50 years shows large variability in the atmospheric, oceanographic and sea-ice variables, as well as in fish stocks. A positive relationship is found between water temperature and the recruitment of cod and redfish, whereas the...

  2. Northern Shrimp (Pandalus borealis) Recruitment in West Greenland Waters

    DEFF Research Database (Denmark)

    Pedersen, S. A.; Storm, L. M.

    2002-01-01

    Lipid class and fatty acid compositions were determined in shrimp larvae (Pandalus borealis and P. montagui) collected along transects across banks on the West Greenland shelf in June 1999, May and July 2000. The lipid class contents were investigated as indices of larval shrimp lipid condition...... and food type. Fatty acid compositions were investigated for lipid biomarkers to establish trophic relationships between larval shrimp and potential prey. Phospholipids were the dominant lipid class in all six pelagic development stages of larval P. borealis and P. montagui, accounting for 80 to 92...

  3. West Greenlandic Eskimo

    DEFF Research Database (Denmark)

    Trondhjem, Naja Blytmann; Fortescue, Michael David

    the principal economic activity. Research projects and language initiatives currently in progress within Greenland will be touched upon, as will the possibilities of communication with North American Inuit. West Greenlandic is unique among the native languages of the North American Arctic and Sub...

  4. Environmental factors affecting recruitment of northern shrimp (Pandalus borealis) in West Greenland waters

    DEFF Research Database (Denmark)

    Wieland, Kai; Siegstad, H.

    2012-01-01

    Survey estimates of biomass of Northern shrimp (Pandalus borealis) in West Greenland waters increased from about 178000 tons in 1998 to about 598000 tons in 2003. The increase in stock size was preceded by several consecutive years in which recruitment was substantially above average. Recruitment...

  5. Seasonal migration, vertical activity and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides (Walbaum) in West Greenland waters

    DEFF Research Database (Denmark)

    Boje, Jesper; Neuenfeldt, Stefan; Sparrevohn, Claus Reedtz

    2014-01-01

    little is known about its behavior and habitat characteristics. We tagged adult Greenland halibut in the waters off Ilulissat with electronic data storage tags that collected information on depth, temperature, and time. Although clear differences between individuals in migration and vertical behavior...

  6. Northern Shrimp (Pandalus borealis) Recruitment in West Greenland Waters

    DEFF Research Database (Denmark)

    Pedersen, S. A.; Storm, L. M.

    2002-01-01

    Lipid class and fatty acid compositions were determined in shrimp larvae (Pandalus borealis and P. montagui) collected along transects across banks on the West Greenland shelf in June 1999, May and July 2000. The lipid class contents were investigated as indices of larval shrimp lipid condition a...

  7. Population Structure of West Greenland Narwhals

    DEFF Research Database (Denmark)

    Riget, F.; Dietz, R.; Møller, P.;

    The hypothesis that different populations of narwhals in the West Greenland area exist has been tested by different biomarkers (metal and organochlorine concentrations, stable isotopes and DNA). Samples of muscle, liver, kidney, blubber and skin tissues of narwhals from West Greenland have been...... isotopes could not support the population structure with two West Greenland populations suggested by the genetic study....

  8. Comparative Carbon and Water Relations of Betula nana and Poa pratensis in West Greenland

    Science.gov (United States)

    Cahoon, S. M. P.; Sullivan, P. F.; Welker, J. M.; Post, E.

    2014-12-01

    The expansion of woody shrubs throughout much of the Arctic in recent decades is a common observation in response to climate change. However, we lack a complete understanding of how woody shrubs differ physiologically from neighboring species and how these differences may confer competitive advantages to woody shrubs as the climate continues to change. At a site in West Greenland, we combined detailed leaf physiological measurements with stable isotope analysis of plant leaf material, xylem water and soil water to elucidate the processes governing seasonal carbon (C) gain in the two dominant plant species at our study site: Betula nana and Poa pratensis. We hypothesized that cooler, drier soils beneath the Betula canopy would result in greater drought sensitivity during times of high atmospheric demand (i.e. greater water vapor pressure deficit; VPD), which would manifest in reduced leaf carbon isotope discrimination (Δ13C), reduced stomatal conductance (gs) and a negative relationship between leaf Δ13C and Δ18O in accordance with the dual-isotope conceptual model. Data collected over two consecutive growing seasons, however, revealed greater drought sensitivity in Poa, which displayed a dramatic reduction in Amax and gs during periods of high VPD, along with reduced leaf Δ13C. Additionally, leaf Δ13C and Δ18O were negatively correlated in Poa, suggesting strong stomatal influence on Δ13C. Conversely, we found no relationship between leaf Δ13C and Δ18O in Betula, indicating that seasonal variation in Δ13C may have been driven primarily by changes in photosynthesis. Our results suggest that, although Poa maintains greater average leaf-level photosynthesis, this species is more susceptible to drought than Betula. Meanwhile, it may be that Betula employs a strategy to avoid drought stress and maintain steady, yet conservative, C gain. This strategy may enable growth to continue during warm and dry conditions, conferring a competitive advantage for Betula in

  9. Water masses in Kangerlussuaq, a large fjord in West Greenland: the processes of formation and the associated foraminiferal fauna

    DEFF Research Database (Denmark)

    Nielsen, Morten Holtegaard; Erbs-Hansen, Dorthe Reng; Knudsen, Karen Luise

    2010-01-01

    The water masses in Kangerlussuaq (Søndre Strømfjord) in West Greenland were studied during both a summer and a winter field survey. In order to obtain an improved understanding of the relationship between the physical oceanography and modern foraminiferal assemblage distributions, conductivity...... dissolution. A monospecific, calcareous assemblage (Elphidium excavatum forma clavata) occurs in the innermost, shallow part, which is strongly influenced by sediment-loaded meltwater during the summer. The outer, shallow part of the fjord is dominated by strong tidal mixing, and in summer the density...

  10. Permafrost degradation in West Greenland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

    2012-01-01

    Important aspects of civil engineering in West Greenland relate to the presence of permafrost and mapping of the annual and future changes in the active layer due to the ongoing climatically changes in the Arctic. The Arctic Technology Centre (ARTEK) has worked more than 10 years on this topic......, Kangerlussuaq, Sisimiut and Nuuk. They are situated in continuous, discontinuous and sporadic permafrost zones. We will show examples of detoriation of permafrost related to present local scale climate observations and large scale climate and permafrost simulations modeled numerically with the GIPL model driven...... by HIRHAM climate projections for Greenland up to 2075. The engineering modelling is based on a risk assessment methodology based on a flow diagram which classify the risk of permafrost degradation causing settlement and stability problems for buildings and infrastructures based on relatively simple...

  11. Variations of the glacio-marine air mass front in West Greenland through water vapor isotopes

    Science.gov (United States)

    Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.

    2012-12-01

    While the isotopic distribution of precipitation has been widely used for research in hydrology, paleoclimatology, and ecology for decades, intensive isotopic studies of atmospheric water vapor has only recently been made possible by spectral-based technology. New instrumentation based on this technology opens up many opportunities to investigate short-term atmospheric dynamics involving the water cycle and moisture transport. We deployed a Los Gatos Water Vapor Isotope Analyzer (WVIA) at Kangerlussuaq, Greenland from July 21 to August 15, and measured the water vapor concentration and its isotopic ratios continuously at 10s intervals. A Danish Meteorological Institute site is located about 1 km from the site of the deployment, and meteorological data is collected at 30 min intervals. During the observation period, the vapor concentration of the ambient air ranges from 5608.4 to 11189.4 ppm; dD and d18O range from -254.5 to -177.7 ‰ and -34.2 to -23.2 ‰, respectively. The vapor content (dew point) and the isotopic ratios are both strongly controlled by the wind direction. The easterly winds are associated with dry, isotopically depleted air masses formed over the glacier, while westerly winds are associated with moist and isotopically enriched air masses from the marine/fjord surface. This region typically experiences katabatic winds off of the ice sheet to the east. However, during some afternoons, the wind shifts 180 degrees, blowing off the fjord to the west. This wind switch marks the onset of a sea breeze, and significant isotopic enrichment results. Enrichment in deuterium is up to 60 ‰ with a mean of 15‰, and oxygen-18 is enriched by 3‰ on average and up to 8 ‰. Other afternoons have no change in wind, and only small changes in humidity and vapor isotopic ratios. The humidity and isotopic variations suggest the local atmosphere circulation is dominated by relatively high-pressure systems above the cold glaciers and cool sea surface, and diurnal

  12. Comparison of remote sensing reflectance from above-water and in-water measurements west of Greenland, Labrador Sea, Denmark Strait, and west of Iceland.

    Science.gov (United States)

    Garaba, Shungudzemwoyo P; Zielinski, Oliver

    2013-07-01

    The need to obtain ocean color essential climate variables (OC-ECVs) using hyperspectral technology has gained increased interest in recent years. Assessing ocean color on a large scale in high latitude environments using satellite remote sensing is constrained by polar environmental conditions. Nevertheless, on a small scale we can assess ocean color using above-water and in-water remote sensing. Unfortunately, above-water remote sensing can only determine apparent optical properties leaving the sea surface and is susceptible to near surface environmental conditions for example sky and sunglint. Consequently, we have to rely on accurate in-water remote sensing as it can provide both synoptic inherent and apparent optical properties of seawater. We use normalized water leaving radiance LWN or the equivalent remote sensing reflectance RRS from 27 stations to compare the differences in above-water and in-water OC-ECVs. Analysis of above-water and in-water RRS spectra provided very good match-ups (R2 > 0.97, MSE < 1.8*10(-7)) for all stations. The unbiased percent differences (UPD) between above-water and in-water approaches were determined at common OC-ECVs spectral bands (410, 440, 490, 510 and 555) nm and the classic band ratio (490/555) nm. The spectral average UPD ranged (5 - 110) % and band ratio UPD ranged (0 - 12) %, the latter showing that the 5% uncertainty threshold for ocean color radiometric products is attainable. UPD analysis of these stations West of Greenland, Labrador Sea, Denmark Strait and West of Iceland also suggests that the differences observed are likely a result of environmental and instrumental perturbations.

  13. Rerouting of subglacial water flow between neighboring glaciers in West Greenland

    Science.gov (United States)

    Chu, Winnie; Creyts, Timothy T.; Bell, Robin E.

    2016-05-01

    Investigations of the Greenland ice sheet's subglacial hydrological system show that the connectivity of different regions of the system influences how the glacier velocity responds to variations in surface melting. Here we examine whether subglacial water flow paths can be rerouted beneath three outlet glaciers in the ablation zone of western Greenland. We use Lamont-Doherty and Center for Remote Sensing of Ice Sheets of University of Kansas (CReSIS) ice-penetrating radar data to create a new ice thickness map. We then use a simple subglacial water flow model to examine whether flow paths can be rerouted and identify the topographic conditions that are sensitive to subglacial rerouting. By varying water pressures within an observationally constrained range, we show that moderate changes in pressure can cause flow paths to reroute and exchange water from one subglacial catchment to another. Flow across subglacial overdeepenings is particularly sensitive to rerouting. These areas have low hydraulic gradients driving flow, so subtle water pressure variations have a strong influence on water flow direction. Based on correlations between water flow paths and ice velocity changes, we infer that water piracy between neighboring catchments can result in a different spatial pattern of hydrologically induced ice velocity speedup depending on the amount and timing of surface melt. The potential for subglacial water to reroute across different catchments suggests that multiple hydrographs from neighboring glaciers are likely necessary to accurately ascertain melt budgets from proglacial point measurements. The relationship between surface runoff, ice dynamics, and proglacial discharge can be altered by rerouting of subglacial water flow within and across outlet glaciers.

  14. A combined DNA-microsatellite and isozyme analysis of the population structure of the harbour porpoise in Danish waters and west Greenland

    DEFF Research Database (Denmark)

    Andersen, L W; Holm, L E; Siegismund, Hans Redlef;

    1997-01-01

    One hundred and twenty-four specimens of the harbour porpoise, Phocoena phocoena, occurring in inner Danish waters (IDW), the North Sea and West Greenland were analysed to study subdivision into genetically differentiated subpopulations using PCR-amplified DNA-microsatellites and isozyme markers...... or nonrandom mating. The analysis of the genetical population structure showed that harbour porpoises from West Greenland, the North Sea and IDW were three geographically, genetically differentiated populations even though connected through some degree of gene flow. A tendency for females to be more stationary...... than males was suggested. Furthermore, the population structure suggested a closer relationship between IDW and the North Sea....

  15. Population Structure of West Greenland Narwhals

    DEFF Research Database (Denmark)

    Riget, F.; Dietz, R.; Møller, P.

    The hypothesis that different populations of narwhals in the West Greenland area exist has been tested by different biomarkers (metal and organochlorine concentrations, stable isotopes and DNA). Samples of muscle, liver, kidney, blubber and skin tissues of narwhals from West Greenland have been...... analysed for heavy metals, organochlorines, stable isotopes and DNA. The obtained results of metal concentrations and DNA were included in the existing database, whereas no previous data on organochlorines and stable isotopes in West Greenland narwhals existed. The metal and POP concentrations and stable...

  16. Genetic structure of West Greenland populations of lumpfish Cyclopterus lumpus

    DEFF Research Database (Denmark)

    Mayoral, Elsa Garcia; Olsen, M.; Hedeholm, R.

    2016-01-01

    In this study, 11 microsatellite markers were used to determine the structure of West Greenlandic lumpfish Cyclopterus lumpus populations across six spawning locations spanning >1500 km and compared with neighbouring populations in Canada and Iceland. To evaluate whether data allow for identifica......In this study, 11 microsatellite markers were used to determine the structure of West Greenlandic lumpfish Cyclopterus lumpus populations across six spawning locations spanning >1500 km and compared with neighbouring populations in Canada and Iceland. To evaluate whether data allow...... for identification of origin of C. lumpus in Greenlandic waters, genetic assignment analysis was performed for 86 C. lumpus sampled on a feeding migration. Significant structuring with isolation by distance was observed in the West Greenland samples and two major subpopulations, north and south, were suggested...

  17. Recognition of > or = 3850 Ma water-lain sediments in West Greenland and their significance for the early Archaean Earth

    Science.gov (United States)

    Nutman, A. P.; Mojzsis, S. J.; Friend, C. R.; Bada, J. L. (Principal Investigator)

    1997-01-01

    A layered body of amphibolite, banded iron formation (BIF), and ultramafic rocks from the island of Akilia, southern West Greenland, is cut by a quartz-dioritic sheet from which SHRIMP zircon 206Pb/207Pb weighted mean ages of 3865 +/- 11 Ma and 3840 +/- 8 Ma (2 sigma) can be calculated by different approaches. Three other methods of assessing the zircon data yield ages of >3830 Ma. The BIFs are interpreted as water-lain sediments, which with a minimum age of approximately 3850 Ma, are the oldest sediments yet documented. These rocks provide proof that by approximately 3850 Ma (1) there was a hydrosphere, supporting the chemical sedimentation of BIF, and that not all water was stored in hydrous minerals, and (2) that conditions satisfying the stability of liquid water imply surface temperatures were similar to present. Carbon isotope data of graphitic microdomains in apatite from the Akilia island BIF are consistent with a bio-organic origin (Mojzsis et al. 1996), extending the record of life on Earth to >3850 Ma. Life and surface water by approximately 3850 Ma provide constraints on either the energetics or termination of the late meteoritic bombardment event (suggested from the lunar cratering record) on Earth.

  18. The Ramsar Sites of Disko, West Greenland

    DEFF Research Database (Denmark)

    Egevang, C.; Boertmann, D.

    The three Ramsar sites of Disko Island in West Greenland were surveyed for breeding and staging waterbirds in July 2001. Two of the areas (no. 1 and 2) held a high diversity of waterbirds and proved to be of international importance for the Greenland white-fronted goose, while the third (no. 3......) held very few waterbirds and hardly meet any of the specific waterbird criteria of the Ramsar convention...

  19. Future markers of the West Greenlandic

    DEFF Research Database (Denmark)

    Trondhjem, Naja Blytmann

    2010-01-01

    Abstract West Greenlandic, a polysynthetic language, belongs to Inuit languages. In Inuktitut (Canada) and West Greenlandic (Inuit languages) tense is marked by optional tense suffixes and in both languages the temporal systems are based on a future/ non-future opposition. In Inuktitut the tense......, and it is used when none of the others can be used. It seems that some of the tense suffixes i.e. past (-sima, perfective, perfect, preterite) and future (-ler, begin, be about to, near future) originally had a more or less concrete aspectual meanings and have developed into more abstract tense meanings...... suffixes have developed a complicated remoteness system. In West Greenlandic the future tense suffixes have a distinction between vague and inevitable future, and the past time suffixes have developed different perfect meanings. In Iñupiaq (Alaska), the temporal system is based on an opposition between...

  20. Occurrence of anisakid nematodes in Atlantic cod (Gadus morhua) and Greenland cod (Gadus ogac), West Greenland

    DEFF Research Database (Denmark)

    Mouritsen, Kim N.; Hedeholm, Rasmus; Schack, Henriette B.;

    2010-01-01

    Anisakid nematodes commonly infect gadids, and are of economic and aesthetic importance to the commercial fishing industry in Greenland as some species are pathogenic to humans. However, very little is known about the occurrence of these parasites and their impact on the hosts in Greenland waters....... During a survey in 2005, stomach sample of 227 Atlantic cod (Gadus morhua) and 64 Greenland cod (Gadus ogac) was collected in Godthaab and Sisimiut fiord systems in West Greenland waters. All cod were dissected for stomach contents and anisakid nematodes were removed from the visceral cavity. Third stage...... nematode species regarding prevalence of infection and mean infection intensity was evident, and there was no relationship between fish condition and the intensity of nematode infections. Standardised for size, capelin-eating cod were in better condition and more heavily infected than fish subsisting...

  1. The lithospheric mantle below southern West Greenland

    DEFF Research Database (Denmark)

    Sand, Karina Krarup; Waight, Tod Earle; Pearson, D. Graham

    2009-01-01

    Geothermobarometry of primarily garnet lherzolitic xenoliths from several localities in southern West Greenland is applied to address the diamond potential, pressure and temperature distribution and the stratigraphy of the subcontinental lithospheric mantle ~600 Ma ago. The samples are from kimbe...... into the reworked Archean North of the Naqssugtoqidian deformation front....

  2. Ice stream retreat following the LGM and onset of the west Greenland current in Uummannaq Trough, west Greenland

    Science.gov (United States)

    Sheldon, Christina; Jennings, Anne; Andrews, John T.; Ó Cofaigh, Colm; Hogan, Kelly; Dowdeswell, Julian A.; Seidenkrantz, Marit-Solveig

    2016-09-01

    The deglacial history and oceanography of Uummannaq Trough, central West Greenland continental shelf, was investigated using foraminiferal, sedimentological, and bathymetric records together with a radiocarbon chronology, providing a timeline for the retreat of glacial ice after the Last Glacial Maximum (LGM). To map ice stream retreat, data were collected from cores from the outer (JR175-VC45 and JR175-VC43) and inner (JR175-VC42) Uummannaq Trough. A large ice stream, fed by confluent glaciers draining the interior of the Greenland Ice Sheet, extended across the outer shelf during the LGM and was in retreat by 15.0 cal kyr BP. Foraminiferal data indicate that the 'warm' West Greenland Current (WGC) was established prior to 14.0 cal kyr BP, which is the hitherto earliest record of Atlantic Water found on the West Greenland shelf. For each of the cores, foraminifera indicate that ice sheet retreat was followed quickly by incursion of the WGC, suggesting that the warm water may have enhanced ice retreat. Prior to the Younger Dryas cold event, the radiocarbon chronology indicates that the ice sheet retreated to the mid-shelf, where it subsequently stabilised and formed a large grounding-zone wedge (GZW). After the Younger Dryas, around 11.5 cal kyr BP, the ice retreated rapidly from the GZW and into the fjords.

  3. Offshore Seabird Distributions during Summer and Autumn at West Greenland

    DEFF Research Database (Denmark)

    Boertmann, D.; Mosbech, A.

    This report presents the phenological and distributional results of seabird surveys carried out by ship in West Greenland waters. In 1977 observations were carried out from stationary platforms (oil exploration supply ships) and in the period 1992 to 2000 observations were carried out from sailing...... ships. The results from 1977 are presented as observations per 5-day periods and give an impression of the species temporal occurrence. The 1992-2000 results are presented as distribution maps. These show densities for more numerous and widespread species, and actual observations for the less numerous....... During the autumn the numbers of seabirds increase as migrants from local and international populations of mainly thick-billed murre and little auk arrive to spend the winter in West Greenland waters. Huge concentrations of thick-billed murres, common eiders and king-eiders may occur then...

  4. Northern Shrimp (Pandalus borealis) Recruitment in West Greenland Waters. Part I. Distribution of Pandalus Shrimp Larvae in Relation to Hydrography and Plankton

    DEFF Research Database (Denmark)

    Pedersen, S. A.; Storm, L. M.; Simonsen, C. S.

    2002-01-01

    Plankton samples and oceanographic data were obtained during transect studies across fishing banks over the West Greenland shelf areas in June 1999, May, and July 2000. The hypothesis that larval shrimp are linked to the behaviour of hydrographic fronts was tested by determining whether larval...... shrimp abundance was linked to plankton distributions, species composition and primary productivity. We found six pelagic developmental stages (ZI–ZVI) in two species of Pandalus larvae. P. borealis was the most abundant species in all stages from ZII to ZVI. The smaller P. montagui larvae were slightly....... The two species showed minor differences in larval distribution across banks and between transects, indicating a wide larval dispersal and a relatively short hatching period. We found no relationship between indices of larval shrimp abundance and the T–S characteristics of water masses, chlorophyll...

  5. Deglacial History and Paleoceanography of the Umanak System, West Greenland

    DEFF Research Database (Denmark)

    Sheldon, Christina; Jennings, Anne; Andrews, John

    2012-01-01

    A record of Greenland Ice Sheet (GIS) and ice-stream history, ice-sheet ocean interactions and paleoclimate from the Last Glacial Maximum to present is preserved in the sediments of the Umanak fjord, shelf trough and trough mouth fan system of central West Greenland. The objective of this study i...

  6. Feeding ecology of Greenland halibut and sandeel larvae off West Greenland

    DEFF Research Database (Denmark)

    Stenberg, Claus; Munk, Peter; Folkvord, A.

    2006-01-01

    Feeding ecology of Greenland halibut (Gr. halibut) (Reinhardtius hippoglossoides) and sandeel (Ammodytes sp.) larvae on the West Greenland shelf was studied during the main part of the productive season (May, June and July). Copepods were the main prey item for larval Gr. halibut and sandeel, con...

  7. Deglacial History and Paleoceanography of the Umanak System, West Greenland

    DEFF Research Database (Denmark)

    Sheldon, Christina; Jennings, Anne; Andrews, John

    2012-01-01

    is to document the timing and rate of ice retreat and the role of the West Greenland Current (WGC) in initiating or sustaining ice retreat. During cruise JR175 of the UK ship RRS James Clark Ross in 2009, sediment cores and geophysical data were collected from the Umanak System to document the glacial history......A record of Greenland Ice Sheet (GIS) and ice-stream history, ice-sheet ocean interactions and paleoclimate from the Last Glacial Maximum to present is preserved in the sediments of the Umanak fjord, shelf trough and trough mouth fan system of central West Greenland. The objective of this study...

  8. Paleoceanographical development off Sisimiut, West Greenland, during the mid- and late Holocene. A multiproxy study

    DEFF Research Database (Denmark)

    Erbs-Hansen, D.R.; Knudsen, K.L.; Olsen, Jesper

    2013-01-01

    A multiproxy study of paleoceanographic and climatic changes in Holsteinsborg Dyb on the West Greenland shelf shows that the area is sensitive to variations in the mixing between the two components of the West Greenland Current, i.e., the Atlantic Water of the Irminger Current and the Polar Water...... from the East Greenland Current. A seismic profile illustrates the general development in the area since the deglaciation, and analyses of benthic foraminifera, stable isotopes (δ18O and δ13C), and X-ray fluorescence elemental counts in two cores, covering ca. 6650 and 1100years, respectively, provide...... details on the oceanographic changes during the mid- and late Holocene. The chronology is based on 210Pb and AMS 14C age determinations. During the time interval of 6650-1600cal.yr BP, the bottom waters are characterized by the presence of modified Atlantic Water, with some influence of meltwater, either...

  9. Quantifying supraglacial meltwater pathways in the Paakitsoq region, West Greenland

    OpenAIRE

    Koziol, C; Arnold, Neil Stuart; Pope, A.; Colgan, W

    2017-01-01

    Increased summer ice velocities on the Greenland ice sheet are driven by meltwater input to the subglacial environment. However, spatial patterns of surface input and partitioning of meltwater between different pathways to the base remain poorly understood. To further our understanding of surface drainage, we apply a supraglacial hydrology model to the Paakitsoq region, West Greenland for three contrasting melt seasons. During an average melt season, crevasses drain ~47% of surface runoff, la...

  10. Contaminants in two West Greenland caribou populations

    Energy Technology Data Exchange (ETDEWEB)

    Gamberg, Mary, E-mail: mary.gamberg@gmail.com [Gamberg Consulting, 708 Jarvis St., Whitehorse, Yukon Y1A 2J2 (Canada); Cuyler, Christine [Greenland Institute of Natural Resources, PO Box 570, 3900 Nuuk, Greenland (Denmark); Wang, Xiaowa [Environment Canada, 867 Lakeshore Rd., Burlington, ON L7S 1A1 (Canada)

    2016-06-01

    Two caribou populations in West Greenland were sampled and the kidneys, liver and muscle analyzed for contaminants, including aluminum, arsenic, cadmium, copper, lead, mercury, selenium and zinc. Although close in proximity, the two populations are topographically separated by an ice cap, which creates different climates and vegetation types in each region. Contaminant levels reflected the differing diets of the two caribou populations. To the south in the wetter lichen-rich region, caribou had significantly more aluminum, arsenic, cadmium, lead, mercury, selenium and zinc, likely due to atmospheric deposition on lichens. To the north in the dry desert steppe where grasses predominate, caribou had higher levels of copper. Cows collected in late winter had significantly less hepatic copper, lead and mercury if pregnant, indicating placental transfer of these elements. Our results suggest that hepatic copper levels < 200 μg g{sup −1} dry weight may result in copper depletion in pregnant cows and hepatic mercury concentrations above 0.5 μg g{sup −1} dry weight may negatively affect fertility in caribou cows. Hepatic mercury levels were negatively correlated with cow body weight, suggesting an adverse effect on body condition. Element concentrations found in tissues from these caribou are not considered to be of a health concern for those consuming this traditional food. - Highlights: • Caribou tissue contaminant profiles may reflect different diets. • Low hepatic copper may result in copper depletion in pregnant caribou. • High hepatic mercury may negatively affect fertility in caribou cows. • Hepatic mercury is negatively correlated with body condition in caribou cows. • Metal levels in tissues are not a health concern to people consuming caribou.

  11. Distribution and drift of Atlantic cod ( Gadus morhua ) eggs and larvae in Greenland offshore waters

    DEFF Research Database (Denmark)

    Wieland, Kai; Hovgård, Holger

    2002-01-01

    Catches of Atlantic cod (Gadus morhua) eggs and larvae from 45 national and international ichthyoplankton surveys conducted in Greenland offshore waters during the period 1950 to 1984 have been compiled and re-analysed. Southeast and Southwest Greenland were identified as im- portant spawning areas...... from which eggs and early larvae drift towards the southern Davis Strait. Only a part of the larval population remained in the vicinity of favourable settling areas off West Greenland while a considerable part was obviously transported westward across the Davis Strait and thus did not contribute...... to the recruitment of the West Greenland cod stock. It is also shown that cod eggs and larvae occasionally drift from Southwest Iceland across the Denmark Strait to the East Greenland shelf from where a subsequent transport and immigration of juveniles to West Greenland waters can occur. Larval transport across...

  12. Climate variability in West Greenland during the past 1500 years

    DEFF Research Database (Denmark)

    dos Santos Ribeiro, Sofia Isabel; Moros, Matthias; Ellegaard, Marianne;

    2012-01-01

    document late-Holocene climate variability in West Greenland as inferred from a marine sediment record from the outer Disko Bay. Organic-walled dinoflagellate cysts and other palynomorphs were used to reconstruct environmental changes in the area through the last c. 1500 years at 30–40 years resolution....... Sea ice cover and primary productivity were identified as the two main factors driving dinoflagellate cyst community changes through time. Our data provide evidence for an opposite climate trend in West Greenland relative to the NE Atlantic region from c. AD 500 to 1050. For the same period, sea......Ribeiro, S., Moros, M., Ellegaard, M. & Kuijpers, A. 2012 (January): Climate variability in West Greenland during the past 1500 years: evidence from a high-resolution marine palynological record from Disko Bay. Boreas, Vol. 41, pp. 68–83. 10.1111/j.1502-3885.2011.00216.x. ISSN 0300-9483. Here we...

  13. Satellite Tracking of Humpback Whales in West Greenland

    DEFF Research Database (Denmark)

    Dietz, R.; Teilmann, J.; Heide-Jørgensen, M.-P.

    In June 2000, 6 humpback whales (Megaptere novaeangliae) were tagged with satellite transmitters off West Greenland. Contact remained for up to 42 days. The tagging revealed that within the month of June, humpback whales off West Greenland moved between Fiskenæs Banke, Fyllas Banke, Tovqussaq Banke......, Sukkertop Banke and Lille Hellefiske Banke. The whales showed a preference for the continental slopes with depths less than 200 m, however, few dives were recorded down to 500 m. The whales had a preference for dives lasting 7-8 min. (15%) and no dives lasted longer than 15 min....

  14. Distribution and abundance of West Greenland humpback whales ( Megaptera novaeangliae )

    DEFF Research Database (Denmark)

    Larsen, Finn; Hammond, P.S.

    2004-01-01

    Photo-identification surveys of humpback whales Megaptera novaeangliae were conducted at West Greenland during 1988-93, the last 2 years of which were part of the internationally coordinated humpback whale research programme YoNAH, with the primary aim of estimating abundance for the West Greenland...... effort. A total of 670 groups of humpback whales was encountered leading to the identification of 348 individual animals. Three areas of concentration were identified: an area off Nuuk; an area at c. 63degrees30'N; and an area off Frederikshab. Sequential Petersen capture-recapture estimates of abundance...

  15. Satellite Tracking of Humpback Whales in West Greenland

    DEFF Research Database (Denmark)

    Dietz, R.; Teilmann, J.; Heide-Jørgensen, M.-P.

    In June 2000, 6 humpback whales (Megaptere novaeangliae) were tagged with satellite transmitters off West Greenland. Contact remained for up to 42 days. The tagging revealed that within the month of June, humpback whales off West Greenland moved between Fiskenæs Banke, Fyllas Banke, Tovqussaq Banke......, Sukkertop Banke and Lille Hellefiske Banke. The whales showed a preference for the continental slopes with depths less than 200 m, however, few dives were recorded down to 500 m. The whales had a preference for dives lasting 7-8 min. (15%) and no dives lasted longer than 15 min....

  16. Report on a Magnetotelluric Study in Kangerlussuaq, West Greenland

    DEFF Research Database (Denmark)

    Kother, Livia Kathleen; Junge, A.; Löwer, A.

    2011-01-01

    Despite a well-mapped, interesting surface geology, deep sounding geophysical studies like seismics or magnetotellurics have been used very rarely in Greenland. The aim of this article is to present the preliminary results of a magnetotelluric study performed in the area of Kangerlussuaq, West...

  17. Tributyltin accumulation and effects in marine molluscs from West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Strand, J.; Asmund, G

    2003-05-01

    Tributyltin is accumulated in marine molluscs living in Greenland, with the highest levels found in harbour areas. - The levels of the antifouling agent tributyltin (TBT) and its breakdown products in bivalves were investigated in 1999-2000 at six areas along the west coast of Greenland with focus on locations inside and outside harbours. In addition female gastropods were examined for the development of TBT-induced masculine characteristics in form of imposex or intersex. The highest TBT concentration, 254 ng g{sup -1} ww, was found in the bivalve Mytilus edulis sampled inside Nuuk harbour, but significant TBT concentrations were also present in bivalves from the other harbour areas. Only low levels of TBT were detected in bivalves sampled outside the harbours and in several of the samples the TBT level was below the detection limit. The examination of neogastropods like Buccinum revealed that imposex development occurred in all the harbours. In contrast, imposex was not found in any neogastropods sampled outside the harbour areas. However, the value of marine neogastropods as indicators of TBT contamination in West Greenland seems limited, because of large species diversity and the difficulties in sampling enough specimens at least with the current sampling strategy. No effects, which could be related to TBT contamination, were found in the most abundant tidal gastropod in West Greenland, Littorina saxatilis.

  18. A new glacier monitoring site in West Greenland

    Science.gov (United States)

    Abermann, J.; van As, D.; Petersen, D.; Nauta, M.

    2014-12-01

    Greenland's mountain glaciers and ice caps have recently been shown to significantly contribute to current and future sea-level rise. Despite their importance in this respect they are heavily undersampled with only about 5 currently monitored glaciers out of more than 20000 distributed over complexly varying climatic regions. In 2012, Asiaq, Greenland Survey initiated therefore a glacier mass balance program at Qassinnguit glacier (64°9'N, 51°17'W), approx. 18 km East of Nuuk, Greenland's capital. The glacier is a representative example for mountain glaciers in South-West Greenland both in terms of size (ca 1 km2) and orientation (N). A dense stake network gives the basis for the determination of the surface mass balance with the glaciological method as well as flow velocity measurements and the first two complete years are presented. An automated camera is used to monitor ablation patterns and the evolution of the snow line. In early 2014, a ground-penetrating radar campaign was performed to determine the glacier volume. Ice thicknesses up to 50 m were measured with a 100 MHz antenna and the glacier was found to be largely cold-based with some minor temperate parts. In addition to direct glaciological measurements at the site, the monitoring program complements a 7 year long time series of runoff, which allows for quantifying Qassinnguit glacier's cryospheric contribution to the total catchment. In summer 2014 an on-glacier automated weather station was installed that measures parameters to determine the surface energy balance. Preliminary results will be presented and put into a larger spatial context by relating them to measurements with the same setup at an outlet glacier of the Greenland ice sheet approximately 100 km further East. Climate between these sites differs considerably with a marked negative West - East precipitation gradient.

  19. Force balance along Isunnguata Sermia, west Greenland

    Directory of Open Access Journals (Sweden)

    Toby Meierbachtol

    2016-09-01

    Full Text Available Ice flows when gravity acts on gradients in surface elevation, producing driving stresses. In the Isunnguata Sermia and Russel Glacier catchments of western Greenland, a 50% decline in driving stress along a flow line is juxtaposed with increasing surface flow speed. Here, these circumstances are investigated using modern observational data sources and an analysis of the balance of forces. Stress gradients in the ice mass and basal drag which resist the local driving stress are computed in order to investigate the underlying processes influencing the velocity and stress regimes. Our results show that the largest resistive stress gradients along the flowline result from increasing surface velocity. However, the longitudinal coupling stresses fail to exceed 15 kPa, or 20% of the local driving stress. Consequently, computed basal drag declines in proportion to the driving stress. In the absence of significant resistive stress gradients, other mechanisms are therefore necessary to explain the observed velocity increase despite declining driving stress. In the study area, the observed velocity - driving stress feature occurs at the long-term mean position of the equilibrium line of surface mass balance. We hypothesize that this position approximates the inland limit where surface meltwater penetrates the bed, and that the increased surface velocity reflects enhanced basal motion associated with seasonal meltwater perturbations.

  20. Strategic environmental impact assessment of hydrocarbon activities in the Disko West area[Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Mosbech, A.; Boertmann, D.; Jespersen, Martin

    2007-05-15

    This publication is a strategic environmental impact assessment of activities related to exploration, development and exploitation of hydrocarbons in the sea of West Greenland between 67 deg. and 71 deg. N (= the Disko West Area). (au)

  1. Estimating the future ice sheet hydropower potential in Paakitsoq, Ilulissat, West Greenland

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Mottram, R.H.; Nielsen, C.

    2008-01-01

    long-term investment for an Arctic community of modest population. Here we present a new bedrock and surface map of the Paakitsoq/Swiss Camp part of the Greenland ice sheet and a prediction of the future discharge up to 2080 AD using regional climate model output, dynamic ice sheet modelling......Meltwater running off the Greenland ice sheet yield significant hydropower potentials in catchments bordering the ice sheet, especially in West and South Greenland. Hydropower has been chosen as the most desired source of energy by the Greenland Home Rule, but recent changes in the Greenland ice...... sheet has emphasized the risk of sudden changes in catchment supply. In this study, we present a thorough investigation of hydropower feasibility at the Paakitsoq basin, near Ilulissat in West Greenland. The catchment is completely dominated by the Greenland ice sheet which provides large quantities...

  2. Intra- and Inter-Seasonal Supra-glacial Water Variability over the West Greenland Ice Sheet as Estimated from Combining High Resolution Satellite Optical Data and a Digital Elevation Model

    Science.gov (United States)

    Brown, M. G.; Tedesco, M.; Smith, L. C.; Rennermalm, A. K.; Yang, K.

    2015-12-01

    The supra-glacial hydrology of the Greenland Ice Sheet (GrIS) plays a crucial role on the surface energy and mass balance budgets of the ice sheet as a whole. The surface hydrology network variability of small streams in the ablation zone of Greenland is poorly understood both spatially and temporally. Using satellites that can spatially resolve the presence and associated properties of small streams, the scientific community is now able to be provided with accurate spatial and temporal analysis of surface hydrology on the ice sheet (that could not have been resolved with other sensors such as those on board MODIS or LANDSAT). In this study we report mapped supra-glacial water networks over a region of the West GrIS (approximately 164 km2) derived from high resolution multispectral satellite imagery from the Quickbird and WorldView - 2 satellites in tandem with a 2 meter stereographic SETSM DEM (digital elevation model). The branching complexity of the identified surface streams is computed from the available DEM as well as the intra- and inter seasonal changes observed in the hydrological system. The stream networks created during the melt season (at several different stages of melting) are compared and discussed as well as the networks mapped between consecutive years for proximate dates. Also, depth and volume estimations for the surface water features identified were extracted via band math algorithms, threshold classifications, and morphological operations. Our results indicate that the higher stream orders have the largest amount of stored surface water per km but the lower stream orders, specifically 1st order with widths of ~ 2 meters, hold more stored surface water overall. We also employ and compare runoff data from the numerical model MAR (Modèle Atmosphérique Régional) to the estimations found using imagery and the DEM.

  3. Petroleum geological activities in West Greenland in 1998

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, F.G.; Boesen, A.; Bojesen-Koefoes, J.A. (and other)

    1999-07-01

    Recent developments, with new exploration both on-and offshore West Greenland in the 1990s, have been strongly driven by encouraging research results. Some of the most important break-through were made in the offshore area where new seismic data revealed large structures, either tilted fault blocks or compressional features, on seismic lines and direct hydrocarbon indicators in the form of flat spots. The discovery of extensive seepage of different oil types in the Disko - Nuussuaq - Svartenhuk Halvoe area, providing evidence of multiple oil-prone source rocks in this area has also been very important in attracting industry to the region. Based on previous successes several new research project were initiated in 1998, and more will follow in 1999 and the years to come. The project cover most aspects of petroleum geology and geophysics both on and offshore West Greenland. Some of these are highlighted at the end of the present article, which also provides a brief account of the field work carried out in 1998; reviews of recent summaries of results from groenArctic's GRO-3 well from which data have been released, and of recent GEUS and industry activities offshore, are also given. (EHS)

  4. Recent North West Greenland climate variability documented by NEEM shallow ice cores

    Science.gov (United States)

    Masson-Delmotte, Valérie; Steen-Larsen, Hans-Christian; Popp, Trevor; Vinther, Bo; Oerter, Hans; Ortega, Pablo; White, Jim; Orsi, Anais; Falourd, Sonia; Minster, Benedicte; Jouzel, Jean; Landais, Amaelle; Risi, Camille; Werner, Martin; Swingedouw, Didier; Fettweis, Xavier; Gallée, Hubert; Sveinbjornsdottir, Arny; Gudlaugsdottir, Hera; Box, Jason

    2014-05-01

    Short water stable isotope records obtained from NEEM ice cores (North West Greenland) have been shown to be sensitive to NW Greenland temperature variations, and sea-ice extent in the Baffin Bay area (Steen-Larsen et al, JGR, 2011), with maximum snowfall deposition during summer, therefore providing information complementary to other Greenland ice core records. At the NEEM deep drilling camp, several snow pits and shallow ice cores have been retrieved and analysed at high resolution (seasonal to annual) for water stable isotopes using mass spectrometry and laser instruments in order to document recent climate variability, complementing and facilitating the interpretation of the long records obtained from the deep ice core which extends back to the last interglacial period (NEEM, Nature, 2013). The different pits and shallow ice core records allow to document the signal to noise ratio and to produce a robust stack back to 1750, and up to 2011. The stack record of annual mean d18O depicts a recent isotopic enrichment in parallel with the Greenland warming inferred from coastal weather stations, and shows that many features of decadal variations are in fact well captured by the low resolution profiles measured along the deep ice core data. Recent variations can therefore be compared to long-term trends and centennial variations of the last Holocene, documented at about 5 year resolution. For the past decades to centuries, the NEEM isotopic records are compared with estimations and simulations of local temperature for different seasons, results from NEEM borehole temperature inversions, d18O records from other Greenland ice cores, large scale modes of variability (NAO and AMO) and with simulations from atmospheric general circulation models equiped with water stable isotopes.

  5. The Vaigat Rock Avalanche Laboratory, west-central Greenland

    Science.gov (United States)

    Dunning, S.; Rosser, N. J.; Szczucinski, W.; Norman, E. C.; Benjamin, J.; Strzelecki, M.; Long, A. J.; Drewniak, M.

    2013-12-01

    Rock avalanches have unusually high mobility and pose both an immediate hazard, but also produce far-field impacts associated with dam breach, glacier collapse and where they run-out into water, tsunami. Such secondary hazards can often pose higher risks than the original landslide. The prediction of future threats posed by potential rock avalanches is heavily reliant upon understanding of the physics derived from an interpretation of deposits left by previous events, yet drawing comparisons between multiple events is normally challenging as interactions with complex mountainous terrain makes deposits from each event unique. As such numerical models and the interpretation of the underlying physics which govern landslide mobility is commonly case-specific and poorly suited to extrapolation beyond the single events the model is tuned to. Here we present a high-resolution LiDAR and hyperspectral dataset captured across a unique cluster of large rock avalanche source areas and deposits in the Vaigat straight, west central Greenland. Vaigat offers the unprecedented opportunity to model a sample of > 15 rock avalanches of various age sourced from an 80 km coastal escarpment. At Vaigat many of the key variables (topography, geology, post-glacial history) are held constant across all landslides providing the chance to investigate the variations in dynamics and emplacement style related to variable landslide volume, drop-heights, and thinning/spreading over relatively simple, unrestricted run-out zones both onto land and into water. Our data suggest that this region represents excellent preservation of landslide deposits, and hence is well suited to calibrate numerical models of run out dynamics. We use this data to aid the interpretation of deposit morphology, structure lithology and run-out characteristics in more complex settings. Uniquely, we are also able to calibrate our models using a far-field dataset of well-preserved tsunami run-up deposits, resulting from the 21

  6. Recurring dynamically induced thinning during 1985 to 2010 on Upernavik Isstrøm, West Greenland

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjaer, K.H.; Korsgaard, N.J.;

    2013-01-01

    Many glaciers along the southeast and northwest coasts of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. In this article, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003to 2009 using high-resolution ice, cloud and land...... elevation satellite laser altimeter data supplemented with altimeter surveys from NASA's Airborne Topographic Mapper during 2002 to 2010. To assess thinning prior to 2002, we analyze aerial photographs from 1985. We document at least two distinct periods of dynamically induced ice loss during 1985 to 2010...... characterized by a rapid retreat of the calving front, increased ice speed, and lowering of the ice surface. The first period occurred before 1991, whereas the latter occurred during 2005 to 2009. Analyses of air and sea-surface temperature suggest a combination of relatively warm air and ocean water...

  7. Mapping and classifying the seabed of the West Greenland continental shelf

    Science.gov (United States)

    Gougeon, S.; Kemp, K. M.; Blicher, M. E.; Yesson, C.

    2017-03-01

    Marine benthic habitats support a diversity of marine organisms that are both economically and intrinsically valuable. Our knowledge of the distribution of these habitats is largely incomplete, particularly in deeper water and at higher latitudes. The western continental shelf of Greenland is one example of a deep (more than 500 m) Arctic region with limited information available. This study uses an adaptation of the EUNIS seabed classification scheme to document benthic habitats in the region of the West Greenland shrimp trawl fishery from 60°N to 72°N in depths of 61-725 m. More than 2000 images collected at 224 stations between 2011 and 2015 were grouped into 7 habitat classes. A classification model was developed using environmental proxies to make habitat predictions for the entire western shelf (200-700 m below 72°N). The spatial distribution of habitats correlates with temperature and latitude. Muddy sediments appear in northern and colder areas whereas sandy and rocky areas dominate in the south. Southern regions are also warmer and have stronger currents. The Mud habitat is the most widespread, covering around a third of the study area. There is a general pattern that deep channels and basins are dominated by muddy sediments, many of which are fed by glacial sedimentation and outlets from fjords, while shallow banks and shelf have a mix of more complex habitats. This first habitat classification map of the West Greenland shelf will be a useful tool for researchers, management and conservationists.

  8. Estimating the future ice sheet hydropower potential in Paakitsoq, Ilulissat, West Greenland

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Mottram, R.H.; Nielsen, C.

    2008-01-01

    Meltwater running off the Greenland ice sheet yield significant hydropower potentials in catchments bordering the ice sheet, especially in West and South Greenland. Hydropower has been chosen as the most desired source of energy by the Greenland Home Rule, but recent changes in the Greenland ice...... sheet has emphasized the risk of sudden changes in catchment supply. In this study, we present a thorough investigation of hydropower feasibility at the Paakitsoq basin, near Ilulissat in West Greenland. The catchment is completely dominated by the Greenland ice sheet which provides large quantities...... of meltwater during the summer season. However, geometrical changes in the ice sheet, for example due to a retreat or an advance of the ice sheet margin, could change the hydrological catchment within the ice sheet. Such a change would have a devastating economical impact as a hydropower plant is a significant...

  9. Caribou, individual-based modeling and mega-industry in central West Greenland

    DEFF Research Database (Denmark)

    Raundrup, Katrine; Nymand, Josephine; Nabe-Nielsen, Jacob

    Spatial distribution of caribou (Rangifer tarandus groenlandicus) in West Greenland is a result of both short and long term changes in the Arctic landscape. To understand present distribution 40 satellite collars were deployed on 40 female caribou in the Akia-Maniitsoq herd, central West Greenland...... in an area. Further, enhanced or lowered hunting pressure, and changed weather conditions can be studied using IBM. Thus, both short and long term changes in the landscape will be studied and provide insights in how the specific spatial changes impact caribou in West Greenland....

  10. Rapid population increase in an introduced muskox population, West Greenland

    Directory of Open Access Journals (Sweden)

    Carsten Riis Olesen

    1993-10-01

    Full Text Available In 1962 and 1965, 27 (13 and 14 muskox yearlings were translocated from East Greenland (71°N to the Angujaartorfiup Nunaa range in West Greenland (67°N. Angujaartorfiup Nunaa is a 6600 km2 icefree, continental area where caribou are indigenous. The climate is strictly continental with a minimum of precipitation but with abundant vegetation. Aerial surveys in 1990 documented that the muskox population has increased to 2600 heads despite quota-based harvesting since 1988. The annual quota was 200, 300 and 400 for 1988, 1989 and 1990, respectively. Distribution of muskoxen shows a significant preference for low altitude habitats southeast of Kangerlussuaq Airport and around Arnangarnup Qoorua (Paradise valley. Annual population increment averages 30% and the calf crop is around 24% of the population. Yearling recruitment in the population reveals that calf mortality during winter is very limited. About half of the 1-year-old females are served and they eventually give birth to their first calf when they turn 2 years old. With half of the 2-year-old females reproducing, the calf/cow ration ranges between 0.9 and 1.0.

  11. Seafloor geomorphology and glacimarine sedimentation associated with fast-flowing ice sheet outlet glaciers in Disko Bay, West Greenland

    Science.gov (United States)

    Streuff, Katharina; Ó Cofaigh, Colm; Hogan, Kelly; Jennings, Anne; Lloyd, Jeremy M.; Noormets, Riko; Nielsen, Tove; Kuijpers, Antoon; Dowdeswell, Julian A.; Weinrebe, Wilhelm

    2017-08-01

    Fast-flowing outlet glaciers currently drain the Greenland Ice Sheet (GIS), delivering ice, meltwater and debris to the fjords around Greenland. Although such glaciers strongly affect the ice sheet's mass balance, their glacimarine processes and associated products are still poorly understood. This study provides a detailed analysis of lithological and geophysical data from Disko Bay and the Vaigat Strait in central West Greenland. Disko Bay is strongly influenced by Jakobshavn Isbræ, Greenland's fastest-flowing glacier, which currently drains ∼7% of the ice sheet. Streamlined glacial landforms record the former flow of an expanded Jakobshavn Isbræ and adjacent GIS outlets through Disko Bay and the Vaigat Strait towards the continental shelf. Thirteen vibrocores contain a complex set of lithofacies including diamict, stratified mud, interbedded mud and sand, and bioturbated mud deposited by (1) suspension settling from meltwater plumes and the water column, (2) sediment gravity flows, and (3) iceberg rafting and ploughing. The importance of meltwater-related processes to glacimarine sedimentation in West Greenland fjords and bays is emphasised by the abundance of mud preserved in the cores. Radiocarbon dates constrain the position of the ice margin during deglaciation, and suggest that Jakobshavn Isbræ had retreated into central Disko Bay before 10.6 cal ka BP and to beyond Isfjeldsbanken by 7.6-7.1 cal ka BP. Sediment accumulation rates were up to 1.7 cm a-1 for ice-proximal glacimarine mud, and ∼0.007-0.05 cm a-1 for overlying distal sediments. In addition to elucidating the deglacial retreat history of Jakobshavn Isbræ, our findings show that the glacimarine sedimentary processes in West Greenland are similar to those in East Greenland, and that variability in such processes is more a function of time and glacier proximity than of geographic location and associated climatic regime.

  12. Impact of deep-sea fishery for Greenland halibut (Reinhardtius hippoglossoides) on non-commercial fish species off West Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Ole A; Bastardie, Francois; Eigaard, Ole Ritzau

    2014-01-01

    . During the period 1988–2011, population abundance and size composition changed as catch and effort in the Greenland halibut fishery increased. Two species showed a significant decrease in abundance, and four populations showed a significant reduction in mean weight of individuals (p , 0.05). Correlation......Since the late 1980s, a deep-sea fishery for Greenland halibut (Reinhardtius hippoglossoides) has been developing gradually in West Greenland. Deep-sea fish species are generally long-lived and characterized by late age of maturity, low fecundity, and slow growth, features that probably cause low...... resilience following overexploitation. In order to evaluate whether populations of nine potential bycatch species are negatively affected by the commercial fishery for Greenland halibut, scientific data from bottom-trawl surveys conducted in the same area and period as the commercial fishery were analysed...

  13. Rapid dynamic thinning events during 1985-2010 on Upernavik Isstrøm, West Greenland

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup;

    Many glaciers along the southeast and northwest coast of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. Here, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003-2009 using high-resolution Ice, Cloud and land Elevation Sat...

  14. Recurring dynamically induced thinning during 1985 to 2010 on Upernavik Isstrom, West Greenland

    NARCIS (Netherlands)

    Khan, Shfaqat Abbas; Kjaer, Kurt H.; Korsgaard, Niels J.; Wahr, John; Joughin, Ian R.; Timm, Lars H.; Bamber, Jonathan L.; van den Broeke, Michiel R.; Stearns, Leigh A.; Hamilton, Gordon S.; Csatho, Bea M.; Nielsen, Karina; Hurkmans, Ruud; Babonis, Greg

    2013-01-01

    Many glaciers along the southeast and northwest coasts of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. In this article, we map elevation changes on Upernavik Isstrom (UI), West Greenland, during 2003 to 2009 using high-resolution ice, cloud and land e

  15. Study of subaqueous melting of Store Glacier, West Greenland using ocean observations and numerical simulations

    Science.gov (United States)

    Xu, Y.; Rignot, E. J.; Menemenlis, D.; van den Broeke, M. R.

    2012-12-01

    Ice discharge from the Greenland Ice Sheet is mainly through tidewater glaciers that terminate in the ocean and melt in contact with ocean waters. Subaqueous melting at the calving front is a direct mechanism for mass loss and a potential trigger for glacier acceleration. We present an analysis of oceanographic data collected in the fjord of Store Glacier, West Greenland during August 2010 and 2012. Using these data, we calculate the subaqueous melt rates. Independently, we employ the Massachusetts Institute of Technology general circulation model (MITgcm), modified to include melting at the calving front and outflow of subglacial water to model the ice melt rates of Store Glacier. Previous 2-D sensitivity studies showed that the subaqueous melt rate reaches several meters per day during the summer, increases non-linearly with subglacial runoff and linearly with ocean thermal forcing, and ceases when subglacial discharge is off during winter. We present new 3-D simulations at very high resolution, with measured oceanic temperature/salinity as boundary conditions, and subglacial runoff from the University of Utrecht's Regional Atmospheric Climate Model outputs on different years and seasons. We compare the ocean observations and numerical simulations and discuss the seasonal and inter-annual variations of subaqueous melting. This study helps evaluate the impact of the ocean on the subaqueous melting of Greenland tidewater glaciers and in turn on glacier mass balance. This work was carried out at University of California, Irvine and at the Jet Propulsion Laboratory under contract with NASA Cryosphere Science Program.

  16. A genetic comparison of West Greenland and Baffin Island (Canada walruses: Management implications

    Directory of Open Access Journals (Sweden)

    Liselotte Wesley Andersen

    2014-12-01

    Full Text Available Until recently Atlantic walruses (Odobenus rosmarus rosmarus have been subject to relatively intense exploitation in West Greenland. Animals in this stock have also been hunted in Nunavut/Canada. However, the demographic identity of these animals and their connection with walruses in neighbouring areas is poorly resolved, hampering the determination of sustainable harvest levels. It has been suggested that walruses in West Greenland are genetically linked with walruses at SE Baffin Island (Canada where they are also hunted for subsistence purposes. To determine the relationship(s between walruses in these areas we conducted a genetic analysis including recent samples from West Greenland, Southeast Baffin Island in western Davis Strait, Hudson Strait in Canada and Northwest Greenland in northern Baffin Bay. Seventeen microsatellite markers were applied to all samples. Walruses in West Greenland and at Southeast Baffin Island did not differ from each other and therefore may be regarded as belonging to the same stock. However, walruses in these two areas differed genetically from both Northwest Greenland and Hudson Strait walruses. These findings support (1 that there are subunits within the range of walruses in the Hudson Strait-Davis Strait-Baffin Bay region and (2 that walruses along E Baffin Island and W Greenland constitute a common population that receive some influx from Hudson Strait. Thus, sustainable catch levels in Southeast Baffin Island (Nunavut and in West Greenland must be set in light of the finding that they belong to the same stock, which is exploited in these two areas. This requires Canadian-Greenlandic co-management of the W Greenland-SE Baffin Island walrus stock.

  17. Soil Response to Aeolian Disturbance in West Greenland

    Science.gov (United States)

    Heindel, R. C.; Culler, L. E.; Chipman, J. W.; Virginia, R. A.

    2015-12-01

    Arctic soils are a critical ecological resource, yet are increasingly vulnerable to global change. In the Kangerlussuaq region of West Greenland, aeolian disturbance is the greatest threat to soil stability, with strong katabatic winds eroding vegetation and soil down to the underlying glacial till or bedrock. Little is known about what controls the distribution and rate of the aeolian erosion, which initially results in a state change from tundra to a deflated and nearly unvegetated ground. It is unclear if vegetation can eventually reestablish after erosion occurs, potentially aided by the biological soil crust (BSC) that develops within the eroded areas, or if this soil loss is an irreversible change in vegetation and soil carbon (C) and nitrogen (N) cycling. Our analysis of high-resolution satellite imagery shows that across the entire study region, deflated ground covers 22% of the terrestrial landscape. Aeolian erosion occurs more frequently closer to the Greenland Ice Sheet and on S-facing slopes. Using lichenometry, we estimate that erosional fronts move across the landscape at rates of 2.5 cm yr-1, leaving unproductive ground in their wake. The onset of widespread aeolian erosion occurred roughly 700-1000 years ago, pointing toward regional cooling and aridity as the drivers behind erosion. Finally, we consider whether the BSCs can improve soil quality enough to allow for full vegetation regrowth. Preliminary results show that while the BSCs fix atmospheric N and increase C storage, the rate of soil quality recovery is extremely slow. Understanding the thresholds between vegetated tundra and eroded ground is critical for predicting how the Kangerlussuaq landscape will respond to anticipated changes in climate and ice sheet dynamics.

  18. Recurring dynamically induced thinning during 1985 to 2010 on Upernavik Isstrøm, West Greenland

    Science.gov (United States)

    Khan, Shfaqat Abbas; KjæR, Kurt H.; Korsgaard, Niels J.; Wahr, John; Joughin, Ian R.; Timm, Lars H.; Bamber, Jonathan L.; Broeke, Michiel R.; Stearns, Leigh A.; Hamilton, Gordon S.; Csatho, Bea M.; Nielsen, Karina; Hurkmans, Ruud; Babonis, Greg

    2013-03-01

    Many glaciers along the southeast and northwest coasts of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. In this article, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003to 2009 using high-resolution ice, cloud and land elevation satellite laser altimeter data supplemented with altimeter surveys from NASA's Airborne Topographic Mapper during 2002 to 2010. To assess thinning prior to 2002, we analyze aerial photographs from 1985. We document at least two distinct periods of dynamically induced ice loss during 1985 to 2010 characterized by a rapid retreat of the calving front, increased ice speed, and lowering of the ice surface. The first period occurred before 1991, whereas the latter occurred during 2005 to 2009. Analyses of air and sea-surface temperature suggest a combination of relatively warm air and ocean water as a potential trigger for the dynamically induced ice loss. We estimate a total catchment-wide ice-mass loss of UI caused by the two events of 72.3 ± 15.8 Gt during 1985 to 2010, whereas the total melt-induced ice-mass loss during this same period is 19.8 ± 2.8 Gt. Thus, 79% of the total ice-mass loss of the UI catchment was caused by ice dynamics, indicating the importance of including dynamically induced ice loss in the total mass change budget of the Greenland ice sheet.

  19. Ice-dammed lake drainage in west Greenland: Drainage pattern and implications on ice flow and bedrock motion

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Bjørk, Anders

    2017-01-01

    Ice-dammed lakes drain frequently in Greenland, but the impacts of these events differ between sites. Here we study the quasi-cyclic behavior of the ~40 km2 Lake Tininnilik in west Greenland and its impact on ice flow and crustal deformation. Data reveal rapid drainage of 1.83 ± 0.17 km3 of water...... in less than 7 days in 2010, leading to a speedup of the damming glacier, and an instantaneous modeled elastic bedrock uplift of 18.6 ± 0.1 mm confirmed by an independent lakeside GPS record. Since ice-dammed lakes are common on Greenland, our results highlight the importance of including other sources...... of surface loading in addition to ice mass change, when assessing glacial isostatic adjustment or elastic rebound using geodetic data. Moreover, the results illustrates a linkage between subglacial discharge and ice surface velocity, important for assessing ice flux, and thus mass balance, in a future...

  20. Ocean forcing of Ice Sheet retreat in central west Greenland from LGM to the early Holocene

    Science.gov (United States)

    Jennings, Anne E.; Andrews, John T.; Ó Cofaigh, Colm; Onge, Guillaume St.; Sheldon, Christina; Belt, Simon T.; Cabedo-Sanz, Patricia; Hillaire-Marcel, Claude

    2017-08-01

    Three radiocarbon dated sediment cores from trough mouth fans on the central west Greenland continental slope were studied to determine the timing and processes of Greenland Ice Sheet (GIS) retreat from the shelf edge during the last deglaciation and to test the role of ocean forcing (i.e. warm ocean water) thereon. Analyses of lithofacies, quantitative x-ray diffraction mineralogy, benthic foraminiferal assemblages, the sea-ice biomarker IP25, and δ18 O of the planktonic foraminifera Neogloboquadrina pachyderma sinistral from sediments in the interval from 17.5-10.8 cal ka BP provide consistent evidence for ocean and ice sheet interactions during central west Greenland (CWG) deglaciation. The Disko and Uummannaq ice streams both retreated from the shelf edge after the last glacial maximum (LGM) under the influence of subsurface, warm Atlantic Water. The warm subsurface water was limited to depths below the ice stream grounding lines during the LGM, when the GIS terminated as a floating ice shelf in a sea-ice covered Baffin Bay. The deeper Uummannaq ice stream retreated first (ca. 17.1 cal ka BP), while the shallower Disko ice stream retreated at ca. 16.2 cal ka BP. The grounding lines were protected from accelerating mass loss (calving) by a buttressing ice shelf and by landward shallowing bathymetry on the outer shelf. Calving retreat was delayed until ca. 15.3 cal ka BP in the Uummannaq Trough and until 15.1 cal ka BP in the Disko Trough, during another interval of ocean warming. Instabilities in the Laurentide, Innuitian and Greenland ice sheets with outlets draining into northern Baffin Bay periodically released cold, fresh water that enhanced sea ice formation and slowed GIS melt. During the Younger Dryas, the CWG records document strong cooling, lack of GIS meltwater, and an increase in iceberg rafted material from northern Baffin Bay. The ice sheet remained in the cross-shelf troughs until the early Holocene, when it retreated rapidly by calving and strong

  1. Surface and sub-surface multi-proxy reconstruction of middle to late Holocene palaeoceanographic changes in Disko Bugt, West Greenland

    Science.gov (United States)

    Moros, Matthias; Lloyd, Jeremy M.; Perner, Kerstin; Krawczyk, Diana; Blanz, Thomas; de Vernal, Anne; Ouellet-Bernier, Marie-Michele; Kuijpers, Antoon; Jennings, Anne E.; Witkowski, Andrzej; Schneider, Ralph; Jansen, Eystein

    2016-01-01

    We present new surface water proxy records of meltwater production (alkenone derived), relative sea surface temperature (diatom, alkenones) and sea ice (diatoms) changes from the Disko Bugt area off central West Greenland. We combine these new surface water reconstructions with published proxy records (benthic foraminifera - bottom water proxy; dinocyst assemblages - surface water proxy), along with atmospheric temperature from Greenland ice core and Greenland lake records. This multi-proxy approach allows us to reconstruct centennial scale middle to late Holocene palaeoenvironmental evolution of Disko Bugt and the Western Greenland coastal region with more detail than previously available. Combining surface and bottom water proxies identifies the coupling between ocean circulation (West Greenland Current conditions), the atmosphere and the Greenland Ice Sheet. Centennial to millennial scale changes in the wider North Atlantic region were accompanied by variations in the West Greenland Current (WGC). During periods of relatively warm WGC, increased surface air temperature over western Greenland led to ice sheet retreat and significant meltwater flux. In contrast, during periods of cold WGC, atmospheric cooling resulted in glacier advances. We also identify potential linkages between the palaeoceanography of the Disko Bugt region and key changes in the history of human occupation. Cooler oceanographic conditions at 3.5 ka BP support the view that the Saqqaq culture left Disko Bugt due to deteriorating climatic conditions. The cause of the disappearance of the Dorset culture is unclear, but the new data presented here indicate that it may be linked to a significant increase in meltwater flux, which caused cold and unstable coastal conditions at ca. 2 ka BP. The subsequent settlement of the Norse occurred at the same time as climatic amelioration during the Medieval Climate Anomaly and their disappearance may be related to harsher conditions at the beginning of the

  2. Measurement campaign for wind power potential in west Greenland

    Science.gov (United States)

    Rønnow Jakobsen, Kasper

    2013-04-01

    Experiences and results from a wind resource exploring campaign 2003- in west Greenland. Like many other countries, Greenland is trying to reduce its dependency of fossil fuel by implementing renewable energy. The main challenge is that the people live on the coast in scattered settlements, without power infrastructure. Based on this a wind power potential project was established in 2002, funded by the Greenlandic government and the Technical University of Denmark. We present results and experiences of the campaign. 1 Field campaign There were only a few climate stations in or close to settlements and due to their positioning and instrumentation, they were not usable for wind resource estimation. To establish met stations in Arctic areas with complex topography, there are some challenges to face; mast positioning in complex terrain, severe weather conditions, instrumentation, data handling, installation and maintenance budget. The terrain in the ice free and populated part, mainly consists of mountains of different heights and shapes, separated by deep fjords going from the ice cap to the sea. With a generally low wind resource the focus was on the most exposed positions close to the settlements. Data from the nearest existing climate stations was studied for background estimations of predominant wind directions and extreme wind speeds, and based on that the first 10m masts were erected in 2003. 2 Instruments The first installations used standard NRG systems with low cost NRG instruments. For most of the sites this low cost setup did a good job, but there were some problems with the first design, including instrument and boom strains. In subsequent years, the systems were updated several times to be able to operate in the extreme conditions. Different types of instruments, data logger and boom systems were tested to get better data quality and reliability. Today 11 stations with heights ranging from 10-50m are installed and equipped according to the IEC standard

  3. Mass balance of the Amitsulôq ice cap, West Greenland

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Bøggild, Carl Egede; Olesen, Ole B.

    2007-01-01

    We present detailed mass balance measurements from the Amitsulôq ice cap in West Greenland spanning from 1982 to 1990. The data includes summer and winter balances from 26 stake locations distributed over five transects covering the whole ice cap. The mass balance measurements are combined with a...... meltwater, linking the hydropower potential of the basin closely to the fate of the adjoining Greenland ice-sheet margin....

  4. Greenland

    Institute of Scientific and Technical Information of China (English)

    陈玮

    2002-01-01

    Greenland is the largest is land in the world.it is in the_____of Europe(欧洲)。Near Greenland is another island.it is small.its_____is lceland.do you think that greenland is green and warm? do you think that iceland is white with ice? if you do,you are______.

  5. Reservoir characterisation of western Nuussuaq, central West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Soenderholm, Martin; Gregers, Dam

    1998-08-01

    The primary objective of the project was to provide the framework for initial quantitative reservoir models from those parts of the Nuussuaq Basin (West Greenland) which, based on present stratigraphic and structural data, seem to have the best exploration potential. Both existing and newly acquired data from geophysical, sedimentological, petrographical, petrophysical, geochemical and diagenesis studies have been used to characterise potential sandstone reservoirs on western Nuussuaq. It is anticipated that the results of the study will contribute to the planning of future exploration and GEUS activities in the region. The main part of the project has focused on data and material from wells drilled by groenArctic Inc. as part of their exploration commitments. These wells are mainly located in a volcanic terrain characterised by abundant oil seeps and where little or nothing was known about the subsurface geology prior to drilling. The volcanic terrain separates major sedimentary outcrop areas of Nuussuaq showing very different depositional environments. Sedimentological, geochemical and palynostratigraphical analyses of the sediments penetrated in the wells have therefore been essential in basin analysis. Main emphasis has been laid on the evaluation of diagenetic alterations with respect to reservoir properties of the GANT-1 core and on palynostratigraphical, lithological and petrophysical analyses of the GRO-3 well which encountered the so far thickest Cretaceous-Tertiary described section in the basin. This final report on the EFP-96 project `Reservoir modelling of western Nuussuaq` summarises the collection of all studies related to reservoir modelling of the Nuussuaq Basin. The combined results from the geophysical surveys, the organic geochemical and diagenesis studies and from the evaluation of GRO-3 have profound implications for future petroleum exploration activities in the Nuussuaq Basin. The geophysical data indicate that large, rotated fault blocks

  6. Seismic stratigraphic architecture of the Disko Bay trough-mouth fan system, West Greenland

    Science.gov (United States)

    Hofmann, Julia C.; Knutz, Paul C.

    2015-04-01

    Spatial and temporal changes of the Greenland Ice Sheet on the continental shelf bordering Baffin Bay remain poorly constrained. Then as now, fast-flowing ice streams and outlet glaciers have played a key role for the mass balance and stability of polar ice sheets. Despite their significance for Greenland Ice Sheet dynamics and evolution, our understanding of their long-term behaviour is limited. The central West Greenland margin is characterized by a broad continental shelf where a series of troughs extend from fjords to the shelf margin, acting as focal points for trough-mouth fan (TMF) accummulations. The sea-ward bulging morphology and abrupt shelf-break of these major depositional systems is generated by prograding depocentres that formed during glacial maxima when ice streams reached the shelf edge, delivering large amounts of subglacial sediment onto the continental slope (Ó Cofaigh et al., 2013). The aim of this study is to unravel the seismic stratigraphic architecture and depositional processes of the Disko Bay TMF, aerially the largest single sedimentary system in West Greenland, using 2D and 3D seismic reflection data, seabed bathymetry and stratigraphic information from exploration well Hellefisk-1. The south-west Disko Bay is intersected by a deep, narrow trough, Egedesminde Dyb, which extends towards the southwest and links to the shallower and broader cross-shelf Disko Trough (maximum water depths of > 1000 m and a trough length of c. 370 km). Another trough-like depression (trough length of c. 120 km) in the northern part of the TMF, indicating a previous position of the ice stream, can be distinguished on the seabed topographic map and the seismic images. The Disko Bay TMF itself extends from the shelf edge down to the abyssal plain (abyssal floor depths of 2000 m) of the southern Baffin Bay. Based on seismic stratigraphic configurations relating to reflection terminations, erosive patterns and seismic facies (Mitchum et al., 1977), the TMF

  7. Greenland

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2014-01-01

    The relationship between Greenland and the European Union (EU) can best be understood by exploring the development from Danish colonialism to a future independent Greenlandic state. In 1985, Greenland became the first territory ever to leave the European Economic Community (EEC) when it opted...... in 1979 and made the 1985 withdrawal possible. On 25 November 2008, a majority of the people of Greenland voted in favour of enhanced home rule – ‘self-government’ – still within formal Danish sovereignty. Denmark and Greenland alike are preparing for a future envisioned as involving climate change......, intensive raw material extraction, new transportation corridors and new claims to sovereignty over the Arctic. Greenland uses this imagined future as a way of enhancing its subjectivity, not the least when dealing with the EU. This article analyses how the Greenlandic self-understanding as being on the way...

  8. Variable influx of West Greenland Current water into the Labrador Current through the last 8000 years, based on a multiproxy study from Trinity Bay, NE Newfoundland

    DEFF Research Database (Denmark)

    Sheldon, Christina; Seidenkrantz, Marit-Solveig; Frandsen, Paul

    2015-01-01

    . This may be explained by a weaker North Atlantic subpolar gyre, transporting less Atlantic Water from the WGC to the (outer) LC. Arctic meltwater transport was reduced as glacial melting decreased at the end of the Holocene Thermal Optimum. At ca. 3 cal kyr BP, bottom waters returned to colder, more stable...... Current (WGC) Davis Strait branch, merging into the relatively cold LC. This Atlantic water influence gradually decreased after ca. 6 cal kyr BP, reaching a minimum at 5 cal kyr BP. In contrast, surface temperatures were relatively low due to cold surface water dominated by sea ice and meltwater carried...... conditions, indicating a slight decrease in bottom-water ventilation. After ca. 2.2 cal kyr BP surface water temperatures dropped and sea ice flux increased. The seafloor of Trinity Bay saw warmer conditions, consistent with a stronger subpolar gyre and increased influx of Atlantic-sourced water....

  9. Snowmelt and runoff modelling of an Arctic hydrological basin in west Greenland

    Science.gov (United States)

    Bøggild, C. E.; Knudby, C. J.; Knudsen, M. B.; Starzer, W.

    1999-09-01

    This paper compares the performance of a conceptual modelling system and several physically-based models for predicting runoff in a large hydrological basin, Tasersuaq, in west Greenland. This basin, which is typical of many Greenland basins, is interesting because of the fast hydrological response to changing conditions. Due to the predominance of exposed bedrock surface and only minor occurrence of sediments and organic soils, there is little restraint to run-off, making the treatment of the snowmelt component of primary importance.Presently a conceptual modelling system, HBV, is applied in Greenland and also in most of the arctic regions of Scandinavia for operational forecasting. A general wish to use hydrological models for other purposes, such as to improve data collection and to gain insight into the hydrological processes has promoted interest in the more physically-based hydrological models. In this paper, two degree-day models, the Danish version of the physically-based SHE distributed hydrological modelling system (MIKE SHE) and the conceptual HBV model are compared with a new model that links MIKE SHE and a distributed energy balance model developed for this study, APUT.The HBV model performs the best overall simulation of discharge, which presently makes it most suited for general forecasting. The combination of MIKE SHE and APUT i.e. a physically based modelling system shows promising results by improving the timing of the initiation of spring flood, but does not perform as well throughout the remaining part of the snowmelt season. The modelling study shows that local parameters such as the snow depletion curve, the temporal snow albedo and perhaps also melt water storage need to be more precisely determined from field studies before physically-based modelling can be improved.

  10. Use of Glacial Fronts by Narwhals (Monodon monoceros) in West Greenland

    Science.gov (United States)

    Laidre, K. L.

    2015-12-01

    Glacial fronts in Greenland are known to be important summer habitat for narwhals (Monodon monoceros), as freshwater runoff and sediment discharge may aggregate prey at the terminus. We investigated the importance of glacial habitat characteristics in determining narwhal visitation. Narwhals (n=18) were instrumented with satellite transmitters in September 1993-1994 and 2006-2007 in Melville Bay, West Greenland. Daily narwhal locations were interpolated using a correlated random walk based on observed filtered locations and associated positional error. We also compiled a database on physical features of 41 glaciers along the northwest Greenland coast. This covered the entire coastal region with narwhal activity. Parameters included glacier ice velocity (km/yr) from radar satellite data, glacier front advance and retreat, and glacier width (km) at the ice-ocean interface derived using front position data digitized from 20-100m resolution radar image mosaics and Landsat imagery. We also quantified relative volumes and extent of glacial ice discharge, thickness of the glacial ice at the terminus (m), and water depth at the terminus (m) from gravity and airborne radar data, sediment flux from satellite-based analysis, and freshwater runoff from a regional atmospheric climate model (RACMO2.3). We quantified whale visits to glaciers at three distances (5, 7, and 10 km) and conducted proximity analyses on annual and monthly time steps. We estimated 1) narwhal presence or absence, 2) the number of 24 h periods spent at glaciers, and 3) the fraction of study animals that visited each glacier. The use of glacial habitat by narwhals expanded to the north and south between the 1990s (n=9 unique glaciers visited) and the 2000s (n=30 visited), likely due to loss of summer fast ice and later fall freeze-up trends (3.5 weeks later since 1979). We used a generalized linear mixed effects framework to quantify the glacier and fjord habitat characteristics preferred by narwhals.

  11. Contemporary proglacial aeolian sediment transport in West Greenland

    Science.gov (United States)

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

    2007-12-01

    Glacial erosion processes produce significance quantities of fine sediments that are washed out from beneath glaciers by meltwater. When deposited on the glacier floodplain they dessicate and strong ice-driven winds can entrain and transport them across the landscape resulting in the formation of sand dunes and loess, and adding very fine particles (dust) to the atmosphere. Recent studies suggest that locally-generated dust can play an important role in regulating albedo and the melting rate of glaciers. Very few field process studies have examined the relationship between sediment-delivery to the proglacial floodplain by meltwater and the subsequent aeolian erosion and deposition of these fine sediments. This research reports the use of semi-isokinetic directional sediment samplers to make an initial assessment of the rates of transport of dust and sand in Sandflugtdalen, a valley adjacent to the West Greenland ice sheet. Vertical arrays (z(m) = 0.18, 0.43, 0.85, 1.4) of samplers were deployed in a down valley transect over a distance of 4 km. Trapped sediments were retrieved after intervals of 1 week and 9 weeks. The mass of sediment collected in the traps varied from 0.002-3.62 g cm2 wk-1. As expected, near surface traps collected more, and coarser, sediment than those deployed at 1.4 m height but the decrease in mass of sediment with height was highly variable. The array closest to the glacier trapped the greatest quantity of suspended sediment and the density of suspended sediment decreased with distance down valley. The flux of aeolian sediment comprises clays, silts and sand-sized particles. Areas of aeolian entrainment, transport and deposition are closely linked to the development and distribution of sediments on the proglacial floodplain which varies considerably in terms of surface roughness. At the east end of the valley, close to the ice sheet, aeolian sediment flux is controlled by sediment supply and topography rather than wind speed. Further down

  12. The use of electromagnetic induction methods for establishing quantitative permafrost models in West Greenland

    Science.gov (United States)

    Ingeman-Nielsen, Thomas; Brandt, Inooraq

    2010-05-01

    The sedimentary settings at West Greenlandic town and infrastructural development sites are dominated by fine-grained marine deposits of late to post glacial origin. Prior to permafrost formation, these materials were leached by percolating precipitation, resulting in depletion of salts. Present day permafrost in these deposits is therefore very ice-rich with ice contents approaching 50-70% vol. in some areas. Such formations are of great concern in building and construction projects in Greenland, as they loose strength and bearing capacity upon thaw. It is therefore of both technical and economical interest to develop methods to precisely investigate and determine parameters such as ice-content and depth to bedrock in these areas. In terms of geophysical methods for near surface investigations, traditional methods such as Electrical Resistivity Tomography (ERT) and Refraction Seismics (RS) have generally been applied with success. The Georadar method usually fails due to very limited penetration depth in the fine-grained materials, and Electromagnetic Induction (EMI) methods are seldom applicable for quantitative interpretation due to the very high resistivities causing low induced currents and thus small secondary fields. Nevertheless, in some areas of Greenland the marine sequence was exposed relatively late, and as a result the sediments may not be completely leached of salts. In such cases, layers with pore water salinity approaching that of sea water, may be present below an upper layer of very ice rich permafrost. The saline pore water causes a freezing-point depression which results in technically unfrozen sediments at permafrost temperatures around -3 °C. Traditional ERT and VES measurements are severely affected by equivalency problems in these settings, practically prohibiting reasonable quantitative interpretation without constraining information. Such prior information may be obtained of course from boreholes, but equipment capable of drilling

  13. Greenland

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2014-01-01

    The relationship between Greenland and the European Union (EU) can best be understood by exploring the development from Danish colonialism to a future independent Greenlandic state. In 1985, Greenland became the first territory ever to leave the European Economic Community (EEC) when it opted for....... On the other hand, the representation of the Greenland–EU relationship as one of sovereign equality – present and future – might just be able to provoke the resources necessary to make the dream come true....

  14. Bacterial communities hitching a hike - a guide to the river system of the Red river, Disko Island, West Greenland

    DEFF Research Database (Denmark)

    Hauptmann, Aviaja Zenia Edna Lyberth; Markussen, Thor N.; Stibal, Marek

    Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact...... of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on Disko Island, West Greenland (69°N). We describe the bacterial community through a river into the estuary...

  15. Rapid dynamic thinning on Upernavik Icestream, West Greenland

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

    The main outlet glaciers in Greenland have more than doubled their contribution to global sea level rise over the last decade. Several studies have shown increase in ice discharge from the main outlet glaciers (notably Kangerdlugssuaq (KG) and Helheim glaciers (HG) in Southeast Greenland, and Jak...... Satellite) laser altimetry data supplemented with altimeter surveys from NASA’s Airborne Topographic Mapper (ATM). To assess thinning prior to 2003, we analyze 1985 aerial photos and derived a 2x2 m grid digital elevation model (DEM)........ Here, we focus on Upernavik Icestream, Northwest Greenland, and show that dynamic thinning on short timescales has been dominating the region at least twice between 1985 and 2010. We map changes on Upernavik Icesteram during 2003-2009 using high-resolution ICESat (Ice, Cloud and land Elevation...

  16. Quantitative reconstruction of Holocene sea ice and sea surface temperature off West Greenland from the first regional diatom data set

    Science.gov (United States)

    Krawczyk, D. W.; Witkowski, A.; Moros, M.; Lloyd, J. M.; Høyer, J. L.; Miettinen, A.; Kuijpers, A.

    2017-01-01

    Holocene oceanographic conditions in Disko Bay, West Greenland, were reconstructed from high-resolution diatom records derived from two marine sediment cores. A modern data set composed of 35 dated surface sediment samples collected along the West Greenland coast accompanied by remote sensing data was used to develop a diatom transfer function to reconstruct April sea ice concentration (SIC) supported by July sea surface temperature (SST) in the area. Our quantitative reconstruction shows that oceanographic changes recorded throughout the last 11,000 years reflect seasonal interplay between spring (April SIC) and summer (July SST) conditions. Our records show clear correlation with climate patterns identified from ice core data from GISP2 and Agassiz-Renland for the early to middle Holocene. The early Holocene deglaciation of western Greenland Ice Sheet was characterized in Disko Bay by initial strong centennial-scale fluctuations in April SIC with amplitude of over 40%, followed by high April SIC and July SST. These conditions correspond to a general warming of the climate in the Northern Hemisphere. A decrease in April SIC and July SST was recorded during the Holocene Thermal Optimum reflecting more stable spring-summer conditions in Disko Bay. During the late Holocene, high April SIC characterized the Medieval Climate Anomaly, while high July SST prevailed during the Little Ice Age, supporting previously identified antiphase relationship between surface waters in West Greenland and climate in NW Europe. This antiphase pattern might reflect seasonal variations in regional oceanographic conditions and large-scale fluctuations within the North Atlantic Oscillation and Atlantic Meridional Overturning Circulation.

  17. Mass balance of the Amitsulôq ice cap, West Greenland

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Bøggild, Carl Egede; Olesen, Ole B.

    2007-01-01

    We present detailed mass balance measurements from the Amitsulôq ice cap in West Greenland spanning from 1982 to 1990. The data includes summer and winter balances from 26 stake locations distributed over five transects covering the whole ice cap. The mass balance measurements are combined with a...... meltwater, linking the hydropower potential of the basin closely to the fate of the adjoining Greenland ice-sheet margin.......We present detailed mass balance measurements from the Amitsulôq ice cap in West Greenland spanning from 1982 to 1990. The data includes summer and winter balances from 26 stake locations distributed over five transects covering the whole ice cap. The mass balance measurements are combined...

  18. Rapid dynamic thinning on Upernavik Icestream, West Greenland

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

    2011-01-01

    The main outlet glaciers in Greenland have more than doubled their contribution to global sea level rise over the last decade. Several studies have shown increase in ice discharge from the main outlet glaciers (notably Kangerdlugssuaq (KG) and Helheim glaciers (HG) in Southeast Greenland, and Jak......) laser altimetry data supplemented with altimeter surveys from NASA’s Airborne Topographic Mapper (ATM). To assess thinning prior to 2003, we analyze 1985 aerial photos and derived a 2x2 m grid digital elevation model (DEM)....

  19. Contamination of arctic Fjord sediments by Pb-Zn mining at Maarmorilik in central West Greenland

    DEFF Research Database (Denmark)

    Perner, Kerstin; Leipe, Thomas; Dellwig, O;

    2010-01-01

    This study focuses on heavy metal contamination of arctic sediments from a small Fjord system adjacent to the Pb-Zn "Black Angel" mine (West Greenland) to investigate the temporal and spatial development of contamination and to provide baseline levels before the mines re-opening in January 2009...... illustrate this transport and spatial distribution pattern of the contaminated material....

  20. Age of Tertiary volcanic rocks on the West Greenland continental margin

    DEFF Research Database (Denmark)

    Larsen, Lotte M.; Pedersen, Asger K.; Tegner, Christian

    2016-01-01

    Radiometric ages for undated parts of the volcanic succession and intrusions in West Greenland were obtained by the 40Ar–39Ar incremental heating method. Acceptable crystallization ages were obtained for 27 samples. Combined with published results the new data provide a volcanic stratigraphy corr...

  1. Time trends of mercury in feathers of West Greenland birds of prey during 1851-2003

    DEFF Research Database (Denmark)

    Dietz, Rune; Riget, Frank Farsø; Boertmann, David

    2006-01-01

    Temporal trends of mercury (Hg) in West Greenland gyrfalcons, peregrine falcons, and white-tailed eagles were determined over 150 years from 1851 to 2003. Hg was measured in the fifth primary feather. Results showed that Hg increased in the order gyrfalcon (lowest)

  2. Greenland

    DEFF Research Database (Denmark)

    Christoffersen, Lisbet

    2015-01-01

    the article includes updated informations regarding church-state relations in Greenland re the latest changes of the Church law......the article includes updated informations regarding church-state relations in Greenland re the latest changes of the Church law...

  3. Parasites as biological tags to track an ontogenetic shift in the feeding behaviour of Gadus morhua off West and East Greenland.

    Science.gov (United States)

    Münster, Julian; Klimpel, Sven; Fock, Heino O; MacKenzie, Ken; Kuhn, Thomas

    2015-07-01

    Parasites, being an integral part of every ecosystem and trophically transmitted along the food webs, can provide detailed insights into the structure of food webs and can close the information gap between short-term stomach content analyses and long-term fish otolith analyses. They are useful for tracking ontogenetic shifts in the host's diet, the occurrence of specific organisms or migratory behaviour of their hosts, even in inaccessible environments. In the present study, stomach content analyses and parasitological examinations were performed on 70 Atlantic cod Gadus morhua, one of the most important high-level predators of small fish in the North Atlantic, caught during one research vessel cruise from West and East Greenlandic waters. Analyses revealed significant differences in fish size with higher values for East Greenland (average total length (TL) of 50.5 cm) compared to West Greenland (average TL of 33.3 cm). Clear differences were also present in prey and parasite composition. Crustacea was the main food source for all fish (IRI = 10082.70), while the importance of teleosts increased with fish size. With a prevalence of 85 % in West Greenland and 100 % in East Greenland, Nematoda were the most abundant parasite group. The results indicate an ontogenetic shift in the diet, which are discussed in the context of the common distribution theory, stock dynamics and migratory behaviour.

  4. Walruses in West Greenland: Where do they belong?

    DEFF Research Database (Denmark)

    Born, E. W.; Andersen, L. W.; Dietz, R.

    identity of walruses in CWG remains undetermined. Genetic studies indicate that CWG-walruses have only little exchange with walruses in Northwest and East Greenland. However, a comparison between walruses from Hudson Strait (HS) in Canada) and CWG indicated a source (HS)-sink (CWG) relationship between...

  5. Neoglacial and historical glacier changes around Kangersuneq fjord in southern West Greenland

    Directory of Open Access Journals (Sweden)

    Weidick, Anker

    2012-12-01

    Full Text Available The Nuup Kangerlua region in southern West Greenland became eglaciated in the early Holocene and by the mid-Holocene, the margin of the Inland Ice was located east of its present position. Discussion of late Holocene changes in the frontal positions of outlets relies on descriptions, paintings, photographs, maps, data from investigations of Norse ruins, aerial photographs and satellite images.The Kangiata Nunaata Sermia glacier system has receded over 20 km during the last two centuries, indicating a marked response to climatic fluctuations during and since the Little Ice Age (LIA. A large advance between 1700 and 1800 was followed by rapid recession in the first half of the 1800s. Limited data from c. 1850–1920 indicate that although the long-term position of the glacier front remained c. 10–12 km behind the LIA maximum, the late 1800s and the early 1900s may have seen a recession followed by an advance that resulted in a pronounced moraine system. The ice-dammed lake Isvand formed during the LIA maximum when meltwater from the western side of Kangiata Nunaata Sermia drained to the Ameralla fjord in the west. This is in contrast to the drainage pattern before the 1700s, when water probably drained to Kangersuneq in the north. Thinning of Kangiata Nunaata Sermia resulted in total drainage of Isvand between 2000 and 2010 and the discharge of water through Austmannadalen has now returned to the same level as that in medieval times.Other outlets in the region, such as Akullersuup Sermia and Qamanaarsuup Sermia have varied in phase with Kangiata Nunaata Sermia, but with amplitudes of only a few kilometres. In contrast, Narsap Sermia has been nearly stationary and Kangilinnguata Sermia may have advanced until the middle of the 1900s.Lowland marine outlets in south-western Greenland were characterised by large amplitude changes during the Neoglacial. Extreme examples, in addition to Kangiata Nunaata Sermia, are Eqalorutsit Killiit Sermiat at the

  6. One million years of glaciation and denudation history in west Greenland.

    Science.gov (United States)

    Strunk, Astrid; Knudsen, Mads Faurschou; Egholm, David L; Jansen, John D; Levy, Laura B; Jacobsen, Bo H; Larsen, Nicolaj K

    2017-01-18

    The influence of major Quaternary climatic changes on growth and decay of the Greenland Ice Sheet, and associated erosional impact on the landscapes, is virtually unknown beyond the last deglaciation. Here we quantify exposure and denudation histories in west Greenland by applying a novel Markov-Chain Monte Carlo modelling approach to all available paired cosmogenic (10)Be-(26)Al bedrock data from Greenland. We find that long-term denudation rates in west Greenland range from >50 m Myr(-1) in low-lying areas to ∼2 m Myr(-1) at high elevations, hereby quantifying systematic variations in denudation rate among different glacial landforms caused by variations in ice thickness across the landscape. We furthermore show that the present day ice-free areas only were ice covered ca. 45% of the past 1 million years, and even less at high-elevation sites, implying that the Greenland Ice Sheet for much of the time was of similar size or even smaller than today.

  7. Horizontal and vertical dynamics of zooplankton and larval fish communities during mid-summer in Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Munk, Peter; Nielsen, Torkel Gissel; Hansen, Benni Winding

    2015-01-01

    Disko Bay is a highly productive inlet at the border between high- and low-arctic sectors of west Greenland. The physical/chemical conditions in the bay have changed during recent decades, specifically during an inflow event in 1996–1997 that led to increased deep-water temperatures. To further...... and vertical distribution patterns, community composition and plankton trophodynamics. Plankton abundance was enhanced near-coast and across the pycnocline, and communities differed between regions. Polar cod (Boreogadus saida) and the sandeel (Ammodytes sp.) were among the abundant fish larvae. Productivity...

  8. Abrupt Holocene climate change as an important factor for human migration in West Greenland.

    Science.gov (United States)

    D'Andrea, William J; Huang, Yongsong; Fritz, Sherilyn C; Anderson, N John

    2011-06-14

    West Greenland has had multiple episodes of human colonization and cultural transitions over the past 4,500 y. However, the explanations for these large-scale human migrations are varied, including climatic factors, resistance to adaptation, economic marginalization, mercantile exploration, and hostile neighborhood interactions. Evaluating the potential role of climate change is complicated by the lack of quantitative paleoclimate reconstructions near settlement areas and by the relative stability of Holocene temperature derived from ice cores atop the Greenland ice sheet. Here we present high-resolution records of temperature over the past 5,600 y based on alkenone unsaturation in sediments of two lakes in West Greenland. We find that major temperature changes in the past 4,500 y occurred abruptly (within decades), and were coeval in timing with the archaeological records of settlement and abandonment of the Saqqaq, Dorset, and Norse cultures, which suggests that abrupt temperature changes profoundly impacted human civilization in the region. Temperature variations in West Greenland display an antiphased relationship to temperature changes in Ireland over centennial to millennial timescales, resembling the interannual to multidecadal temperature seesaw associated with the North Atlantic Oscillation.

  9. Magnetotelluric investigation in West Greenland - considering the polar electrojet, ocean and fjords

    DEFF Research Database (Denmark)

    Lauritsen, Nynne Louise Berthou

    A magnetotelluric survey has been conducted in North West Greenland, with the purpose of investigating the subsurface. The results of two processing techniques are presented, a single station robust processing and a multiple station processing. The multiple station processing tries to eliminate...... on induction arrows is presented, illustrating the importance of including these in magnetotelluric modelling. This informationis included in the 3D modelling of the magnetotelluric survey in Greenland, together with the bathymetry of the ocean. The modelling shows that the impact from the fjords and ocean...

  10. A Comparison of Geoid Undulations for West Central Greenland

    Science.gov (United States)

    Roman, Daniel R.; Csatho, Beata; Jezek, Kenneth C.; Thomas, Robert H.; Krabill, William B.; vonFrese, Ralph R. B.; Forsberg, Rene

    1997-01-01

    The accuracy of a new local gravity field model, GEOID94A, is examined at a site on the western Greenland ice sheet. The model, developed by the Danish National Survey and Cadastre, incorporates several new gravity data sets including an extensive amount of airborne gravity data. Model-derived geoid undulations were compared to independently determined undulations found by differencing the elevations from Global Positioning System controlled airborne laser altimetry and optical leveling surveys. Differences between the two sets of undulations were less than +/- 6 cm RMS. The comparison improved (+/- 5 cm RMS) when GEOID94A undulations were adjusted by local gravity observations also acquired at the site. Our comparisons demonstrate that GEOID94A adequately models the long to intermediate wavelengths of the gravity field. We conclude that GEOID94A constitutes a reliable reference model for studies of Greenland's gravity field.

  11. Fecundity of Greenland halibut (Reinhardtius hippoglossoides Walbaum) in East Greenland waters

    DEFF Research Database (Denmark)

    Gundersen, Agnes Christine; Rønneberg, Jan Erich; Boje, Jesper

    2001-01-01

    Fecundity is described for Greenland halibut, based on ovaries collected in July 1997 in ICES Division XIVb in East Greenland waters. The mean potential fecundity was estimated to be 113700 (range 32500–277100). Fecundity was significantly determined by total length. Fecundity–length and fecundity......–weight (round and gutted) relationships were estimated. Vitellogenic oocytes appearing dark in the microscope with a diameter ranging from 900 to 1650μm were counted and used in the fecundity estimates. This stage was easily distinguished from an early vitellogenic stage, with a diameter ranging from 490...

  12. Meltwater chemistry and solute export from a Greenland Ice Sheet catchment, Watson River, West Greenland

    DEFF Research Database (Denmark)

    Yde, Jacob C; Knudsen, N. Tvis; Hasholt, Bent

    2014-01-01

    –2010 for the Watson River sector of the GrIS that drains into the fjord Kangerlussuaq. The hydrochemistry is dominated by Ca2+ and HCO3− with a relatively high molar K+/Na+ ratio of 0.6 ± 0.1, typical for meltwaters draining a gneissic lithology. Low molar Ca2+/Na+ and Mg2+/Na+ ratios indicate that weathering....... However, when normalized by discharge the denudation rates are comparable to other Arctic sites. When extrapolating the results from the Watson River catchment to the entire Greenland for 2007–2010, the solute export from Greenland meltwater varied between 7.1 × 106 and 7.8 × 106 tons, whilst the major...

  13. Characterizing the Frequency and Elevation of Rapid Drainage Events in West Greenland

    Science.gov (United States)

    Cooley, S.; Christoffersen, P.

    2016-12-01

    Rapid drainage of supraglacial lakes on the Greenland Ice Sheet is critical for the establishment of surface-to-bed hydrologic connections and the subsequent transfer of water from surface to bed. Yet, estimates of the number and spatial distribution of rapidly draining lakes vary widely due to limitations in the temporal frequency of image collection and obscureness by cloud. So far, no study has assessed the impact of these observation biases. In this study, we examine the frequency and elevation of rapidly draining lakes in central West Greenland, from 68°N to 72.6°N, and we make a robust statistical analysis to estimate more accurately the likelihood of lakes draining rapidly. Using MODIS imagery and a fully automated lake detection method, we map more than 500 supraglacial lakes per year over a 63000 km2 study area from 2000-2015. Through testing four different definitions of rapidly draining lakes from previously published studies, we find that the number of rapidly draining lakes varies from 3% to 38%. Logistic regression between rapid drainage events and image sampling frequency demonstrates that the number of rapid drainage events is strongly dependent on cloud-free observation percentage. We then develop three new drainage criteria and apply an observation bias correction that suggests a true rapid drainage probability between 36% and 45%, considerably higher than previous studies without bias assessment have reported. We find rapid-draining lakes are on average larger and disappear earlier than slow-draining lakes, and we also observe no elevation differences for the lakes detected as rapidly draining. We conclude a) that methodological problems in rapid drainage research caused by observation bias and varying detection methods have obscured large-scale rapid drainage characteristics and b) that the lack of evidence for an elevation limit on rapid drainage suggests surface-to-bed hydrologic connections may continue to propagate inland as climate warms.

  14. Rapid dynamic thinning events during 1985-2010 on Upernavik Isstrøm, West Greenland

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup;

    Many glaciers along the southeast and northwest coast of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. Here, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003-2009 using high-resolution Ice, Cloud and land Elevation...... Satellite (ICESat) laser altimeter data supplemented with altimeter surveys from NASA's Airborne Topographic Mapper (ATM) during 2002-2010. To assess thinning prior to 2002, we analyze aerial photographs from 1985. We document at least two distinct ice loss events characterized by rapid dynamic thinning......, increased ice speed, and a retreat of the calving front. The most recent event coincides with the speedup of several glaciers along the northwest coast of Greenland in 2005, and with changes in the rate of mass loss observed using data from the Gravity Recovery and Climate Experiment (GRACE) satellite...

  15. Seasonal variability of the circulation system in a West Greenland tidewater outlet glacier fjord, Godthåbsfjord (64°N)

    DEFF Research Database (Denmark)

    Mortensen, John; Bendtsen, Jørgen; Lennert, Kunuk

    2014-01-01

    due to melting of the ice sheet. However, very few observational studies describe the seasonal dynamics of fjord circulation. Here we present the first continuous current measurements (April–November) from a deep mooring deployed in a west Greenland tidewater outlet glacier fjord. Four distinct...... circulation phases are identified during the period, and they are related to exchange processes with coastal waters, tidal mixing, and melt processes on the Greenland Ice Sheet. During early summer, warm intermediate water is transported toward the glacier at an average velocity of about 7 cm s−1. In late......Many tidewater outlet glacier fjords surround the coast of Greenland, and their dynamics and circulation are of great importance for understanding the heat transport toward glaciers from the ice sheet. Thus, fjord circulation is a critical aspect for assessing the threat of global sea level rise...

  16. Freshwater discharge and sediment transport to Kangerlussuaq Fjord, West Greenland

    DEFF Research Database (Denmark)

    Mikkelsen, Andreas Peter Bech

    The main objectives of this PhD study have been to quantify the large-scale hydrological and geomorphological processes and implications related to three large proglacial rivers draining into Kangerlussuaq Fjord from the Greenland Ice Sheet (GrIS). These rivers are Watson, Umivit and Sarfartoq...... and was applied to investigate detailed processes such as storage and release of meltwater from the glacial system. It showed promising first results, though better constrained input data is needed before firm conclusions on detailed processes can be drawn. In July 2012, a several day long period of unprecedented...

  17. A comparison of geoid undulations for west central Greenland

    DEFF Research Database (Denmark)

    Roman, D.R.; Csatho, B.; Jezek, K.C.;

    1997-01-01

    The accuracy of a new local gravity field model, GEOID94A, is examined at a site on the western Greenland ice sheet. The model, developed by the Danish National Survey and Cadastre, incorporates several new gravity data sets including an extensive amount of airborne gravity data. Model-derived ge......The accuracy of a new local gravity field model, GEOID94A, is examined at a site on the western Greenland ice sheet. The model, developed by the Danish National Survey and Cadastre, incorporates several new gravity data sets including an extensive amount of airborne gravity data. Model......-derived geoid undulations were compared to independently determined undulations found by differencing the elevations from Global Positioning System controlled airborne laser altimetry and optical levelling surveys. Differences between the two sets of undulations were less than +/-6 cm RMS. The comparison...... improved (+/-5 cm RMS) when GEOID94A undulations were adjusted by local gravity observations also acquired at the site. Our comparisons demonstrate that GEOID94A adequately models the long to intermediate wavelengths of the gravity field. We conclude that GEOID94A constitutes a reliable reference model...

  18. Regional and inter annual patterns of heavy metals, organochlorines and stable isotopes in narwhals (Monodon monoceros) from West Greenland

    DEFF Research Database (Denmark)

    Dietz, R.; Riget, F.; Hobson, K.A.

    2004-01-01

    , indicating a temporal decrease of SigmaPCBs. SigmaPCBs, DDTs, HCHs and toxaphenes seem to be at similar levels in West Greenland and Arctic Canada, which can be explained by the close winter distributions of populations as well as large ranges in concentrations, time span, number of analyses and the size....../age composition of the data. PCB and DDT concentrations in West Greenland narwhals were half those found in East Greenland and Svalbard. Stable-carbon isotope ratios in muscle of 150 narwhals showed a decreasing trend in the first year when they gradually reduced their dependency on mother's milk, after which...

  19. Modelling the ocean circulation on the West Greenland shelf with special emphasis on northern shrimp recruitment

    Science.gov (United States)

    Hvid Ribergaard, Mads; Anker Pedersen, Søren; Ådlandsvik, Bjørn; Kliem, Nicolai

    2004-08-01

    The ocean circulation on the West Greenland shelf are modelled using a 3D finite element circulation model forced by wind data from the Danish Meteorological Institute-High-Resolution Limited Area Model operational atmospheric model for the Greenland area and tides at the open boundary. Residual anticyclonic eddies are generated around the shelf banks north of 64∘N and areas of permanent upwelling are located west of the shelf banks. The potential distances of shrimp larvae transport from larval release to settling at the bottom were studied, using a particle-tracking model. Particles released (hatched shrimp larvae) south of 62∘N had a probability of about 2% of being lost to the Canadian Shelf, whereas for particles released north of 64∘N almost none were lost from the West Greenland Shelf. The particles tended to have long retention times at the shelf banks caused by the residual anticyclonic eddies. The retention times increased slightly for particles tracked at depths from 80 to 30 m with minor implications for potential transport distances of larval shrimp and plankton.

  20. Walruses in West Greenland: Where do they belong?

    DEFF Research Database (Denmark)

    Born, E. W.; Andersen, L. W.; Dietz, R.

    ) transmitted for more than 3 months during which time she moved from CWG west to SE Baffin Island (SE BI). Hence, the studies supported a suspected connection between walruses in CWG and the HS-SE BI area. Future studies include a genetic comparison of biopsies from SE BI and CWG, and deployment of satellite...

  1. The summer 2012 Greenland heat wave: monitoring water vapour isotopic composition along an atmospheric river event

    Science.gov (United States)

    Bonne, Jean-Louis; Steen-Larsen, Hans Christian; Masson-Delmotte, Valérie; Sodemann, Harald; Lacour, Jean-Lionel; Risi, Camille; Werner, Martin; Clerbaux, Cathy; Fettweis, Xavier

    2014-05-01

    In July 2012, an extreme warm event occurred in Greenland, leading to surface melt over almost all the ice sheet. This event was recorded in the isotopic composition of water vapour measured by the IASI satellite along the transport pathway and at two sites where continuous in situ surface vapour isotopic measurements were conducted, situated at a coastal station of South Greenland (Ivittuut) and further North on top of the ice sheet (NEEM, NW Greenland). These observations allowed us to monitor the isotopic composition of the air mass at different stages of its advection towards Greenland, which can inform on processes along this trajectory, such as cloud properties and moisture sources. In addition, two simulations of this event, using the atmospheric general circulation models LMDZiso and ECHAM5wiso equipped with water stable isotopes and nudged towards large scale wind fields, are investigated. Furthermore, a regional high-resolution model was used to study the moisture transport to Greenland during this event using tagged water tracers of the North Atlantic ocean and coastal land evaporation. Using moisture source diagnostic based on the Lagrangian particle dispersion model Flexpart, we show that this 2012 heat wave event corresponds to moisture sources located over the subtropical Atlantic Ocean, where intense evaporation was caused by dry air masses associated with the US intense summer drought. This moisture was then advected northward along a narrow band, due to a very stationary surface cyclone southwest of Greenland, reached southern Greenland and Ivittuut coastal station on July 9th, travelled along the west coast of Greenland, continued eastwards above the ice sheet and arrived above the NEEM deep drilling camp on July 11th. Surface isotopic observations during the event show larger variations at NEEM than in Ivittuut, strongly reducing the isotopic and deuterium excess latitudinal gradient usually observed between South and North Greenland. This

  2. Investigating a newly discovered firn aquifer on Disko Ice Cap, west Greenland: Insights from ground observations, remote sensing, and modeling

    Science.gov (United States)

    Trusel, L. D.; Das, S. B.; Smith, B.; Kuipers Munneke, P.; Evans, M. J.; Frey, K. E.; Osman, M.; York, A.

    2015-12-01

    Expanding and intensifying surface melt have accelerated contributions from Greenland to global sea level rise in recent decades. Yet, important questions remain regarding the evolution and eventual fate of this meltwater over time and space, a fact underscored by recent observations of expansive aquifers within the Greenland Ice Sheet firn. In April 2015 we observed liquid water retained at depth in an ice cap on Disko Island, central west Greenland. Two adjacent ~20 m firn/ice cores were collected before intercepting a layer saturated with liquid water as evident by water drainage from our cores. Borehole temperature profiling confirms increasing temperature with depth, revealing 0°C isothermal firn below ~10 m depth. Detailed physical stratigraphic analyses conducted on these cores allow us to assess firn properties and their small scale (1 m) and likely impermeable refrozen melt horizons exist above the inferred aquifer surface, raising questions about processes of aquifer formation. To discern the spatial character of the observed firn liquid water and melt stratigraphy, we utilize ground penetrating radar collected in 2014, as well as airborne radar data collected through NASA Operation IceBridge in 2012 and 12 days prior to our field observations in 2015. Glaciochemical analyses on our ice cores reveal preservation of an annual signal allowing derivation of net snow accumulation rates. Combined with surface mass balance modeled by RACMO2.3 and melt assessed via microwave remote sensing, we investigate the recently prevailing climatic and glaciological conditions on Disko. This work will provide new insights into mechanisms of firn aquifer formation and sustenance more broadly, as well as the representation of aquifers in existing radar observations and firn models.

  3. Ice-dammed lake drainage cools and raises surface salinities in a tidewater outlet glacier fjord, west Greenland

    Science.gov (United States)

    Kjeldsen, K. K.; Mortensen, J.; Bendtsen, J.; Petersen, D.; Lennert, K.; Rysgaard, S.

    2014-06-01

    The drainage of ice-dammed lakes in the form of outburst floods in Greenland is detected regularly by remote sensing, and these events are expected to occur more frequently in a warmer climate. However, their impact on ice sheet stability and neighboring water bodies is still unknown. In this interdisciplinary study, we investigate lake drainages from the Greenland Ice Sheet into a west Greenland fjord by analyzing simultaneous time series of satellite observations and direct hydrographic measurements of temperature and salinity in the fjord. Satellite images show that, in general, lake drainages have occurred quasiperiodically during the last decade. A particular sequence of drainage events was observed by satellite in 2009 and was analyzed together with the first direct hydrographic observations. Signs of ice-dammed lake drainages were observed by a downstream mooring located just below the intertidal zone. The release of freshwater occurred at the fjord subsurface at a tidewater outlet glacier. The downstream in-water sequence of property changes in relation to these drainage events was observed as an almost immediate decrease in surface layer temperature (~2°C) followed within a week by the arrival of a high-saline pulse (~ +5 units) with elevated salinity lasting for several days during the passage. During lake drainages, large amounts of relatively warm and saline intermediate water are brought to the near-surface layers by entrainment processes near the glacier front, and this influences the hydrography of the fjord but also impacts the ecosystem through upwelling of nutrient-rich intermediate water.

  4. Automated Ground-based Time-lapse Camera Monitoring of West Greenland ice sheet outlet Glaciers: Challenges and Solutions

    Science.gov (United States)

    Ahn, Y.; Box, J. E.; Balog, J.; Lewinter, A.

    2008-12-01

    Monitoring Greenland outlet glaciers using remotely sensed data has drawn a great attention in earth science communities for decades and time series analysis of sensory data has provided important variability information of glacier flow by detecting speed and thickness changes, tracking features and acquiring model input. Thanks to advancements of commercial digital camera technology and increased solid state storage, we activated automatic ground-based time-lapse camera stations with high spatial/temporal resolution in west Greenland outlet and collected one-hour interval data continuous for more than one year at some but not all sites. We believe that important information of ice dynamics are contained in these data and that terrestrial mono-/stereo-photogrammetry can provide theoretical/practical fundamentals in data processing along with digital image processing techniques. Time-lapse images over periods in west Greenland indicate various phenomenon. Problematic is rain, snow, fog, shadows, freezing of water on camera enclosure window, image over-exposure, camera motion, sensor platform drift, and fox chewing of instrument cables, and the pecking of plastic window by ravens. Other problems include: feature identification, camera orientation, image registration, feature matching in image pairs, and feature tracking. Another obstacle is that non-metric digital camera contains large distortion to be compensated for precise photogrammetric use. Further, a massive number of images need to be processed in a way that is sufficiently computationally efficient. We meet these challenges by 1) identifying problems in possible photogrammetric processes, 2) categorizing them based on feasibility, and 3) clarifying limitation and alternatives, while emphasizing displacement computation and analyzing regional/temporal variability. We experiment with mono and stereo photogrammetric techniques in the aide of automatic correlation matching for efficiently handling the enormous

  5. Suicides in the midnight sun--a study of seasonality in suicides in West Greenland

    DEFF Research Database (Denmark)

    Björkstén, Karin Sparring; Bjerregaard, Peter; Kripke, Daniel F

    2005-01-01

    Greenland is the most extreme of human habitats in regard to annual changes in natural light. From being very low, the rate of suicides in Greenland has increased during the past few decades to be among the highest in the world. Several studies have shown seasonality in suicides with spring...... or summer peaks, but this has not been previously shown in Greenland. Official data from 1968 to 1995 from West Greenland were pooled. A significant seasonality in the 833 suicides was found using Rayleigh's test, a peak in June and a trough in the winter. Suicides increased during the period, and reached...... high rates in most age groups, up to 577 per 100,000 person-years in men aged 15-24 years in 1990, and up to 147 per 100,000 person-years in women aged 15-24 years in 1995. Violent methods of suicide were used by 93%. Depression has been reported uncommonly. High alcohol intake and extended periods...

  6. Predicting spectral and PAR light attenuation in Greenlandic coastal waters

    DEFF Research Database (Denmark)

    Murray, Ciarán; Markager, Stiig; Stedmon, Colin

    The spectral quality and penetration of light are key parameters controlling the productivity of Greenlandic fjords. Solar elevation and sea ice play an important role, but during the increasing ice free period and summer months in particular, light is also regulated by water constituents. We pre...

  7. Predicting Spectral and PAR Light Attenuation in Greenlandic Coastal Waters

    DEFF Research Database (Denmark)

    Murray, Ciarán; Stedmon, Colin A.; Markager, Stiig

    The spectral quality and penetration of light are key parameters controlling the productivity of Greenlandic fjords. Solar elevation and sea ice play an important role, but during the increasing ice free period and summer months in particular, light is also regulated by water constituents. We pre...

  8. Geologic Assessment of Undiscovered Oil and Gas Resources of the West Greenland-East Canada Province

    Science.gov (United States)

    Schenk, Christopher J.

    2010-01-01

    The U.S. Geological Survey (USGS) recently assessed the potential for undiscovered oil and gas resources of the West Greenland-East Canada Province as part of the USGS Circum-Arctic Resource Appraisal program. The province lies in the offshore area between western Greenland and eastern Canada and includes Baffin Bay, Davis Strait, Lancaster Sound, and Nares Strait west of and including part of Kane Basin. A series of major tectonic events led to the formation of several distinct structural domains that are the geologic basis for defining five assessment units (AU) in the province, all of which are within the Mesozoic-Cenozoic Composite Total Petroleum System (TPS). Potential petroleum source rocks within the TPS include strata of Ordovician, Early and Late Cretaceous, and Paleogene ages. The five AUs defined for this study-the Eurekan Structures AU, Northwest Greenland Rifted Margin AU, Northeast Canada Rifted Margin AU, Baffin Bay Basin AU, and the Greater Ungava Fault Zone AU-encompass the entire province and were assessed for undiscovered, technically recoverable resources.

  9. Holocene glacial history of the west Greenland Ice Sheet inferred from cosmogenic exposure ages and threshold lakes

    DEFF Research Database (Denmark)

    Larsen, Nicolaj Krog; Kjaer, K. H.; Colding, Sune Oluf

    2011-01-01

    In this study, we use a combination of 10Be exposure ages and threshold lakes to constrain the ice sheet history in Godthåbs- and Buksefjorden, west Greenland (63-64°N) during the Holocene. The 10Be cosmogenic exposure ages have been used to quantify both the ice retreat and thinning of the west ......) and this suggest that the ice sheet in this area may have been more retracted and probably more sensitive to climate change than other areas in south and west Greenland....

  10. Runoff simulations from the Greenland ice sheet at Kangerlussuaq from 2006-2007 to 2007/08. West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Mernild, Sebastian Haugard [Los Alamos National Laboratory; Hasholt, Bent [UNIV OF COPENHAGEN; Van Den Broeke, Michiel [UTRECHT UNIV; Liston, Glen [COLORADO STATE UNIV

    2009-01-01

    This study focuses on runoff from a large sector of the Greenland Ice Sheet (GrIS) - the Kangerlussuaq drainage area, West Greenland - for the runoff observation period 2006/07 to 2007/08. SnowModel, a state-of-the-art snow-evolution modeling system, was used to simulate winter accumulation and summer ablation processes, including runoff. Independent in situ end-of-winter snow depth and high-resolution runoff observations were used for validation of simulated accumulation and ablation processes. Runoff was modeled on both daily and hourly time steps, filling a data gap of runoff exiting part of the GrIS. Using hourly meteorological driving data instead of smoothed daily-averaged data produced more realistic meteorological conditions in relation to snow and melt threshold surface processes, and produced 6-17% higher annual cumulative runoff. The simulated runoff series yielded useful insights into the present conditions of inter-seasonal and inter-annual variability of Kangerlussuaq runoff, and provided an acceptable degree of agreement between simulated and observed runoff. The simulated spatial runoff distributions, in some areas of the GrIS terminus, were as high as 2,750 mm w.eq. of runoff for 2006/07, while only 900 mm w.eq was simulated for 2007/08. The simulated total runoff from Kangerlussuaq was 1.9 km{sup 3} for 2006/07 and 1.2 km{sup 3} for 2007/08, indicating a reduction of 35-40% caused by the climate conditions and changes in the GrIS freshwater storage. The reduction in runoff from 2006/07 to 2007/08 occurred simultaneously with the reduction in the overall pattern of satellite-derived GrIS surface melt from 2007 to 2008.

  11. The influence of climatic and physiological performance on population dynamics of Mytilus edulis in West Greenland

    DEFF Research Database (Denmark)

    Thyrring, Jakob; Blicher, Martin; Sejr, Mikael Kristian

    2014-01-01

    . Results show an overall decline in blue mussel abundance along the coast from south to north Greenland. Physiological adaptation and plasticity of blue mussels was found across latitudes spanning from the temperate to the High Arctic region. Combined our results indicate that low ocean temperature per se....... The blue mussel (Mytilus edulis) has recently expanded its northern distribution in Greenland and is considered to be a sensitive indicator of climate changes. Blue mussels could be a species that would respond to a warmer climate by increased abundance and growth rates in the Arctic. However, adequate...... data on current distribution and physiological performance of blue mussels in the Arctic is lacking, and knowledge of how “climate” in a broad sense specifically influence population dynamics of this species is unknown. Here, we present data on abundance, age and mortality of blue mussels in West...

  12. Impact of fine debris on ice melt rates at Russell Glacier, central-west Greenland

    Science.gov (United States)

    Carr, Rachel; Linighan, James; Cumming, Alex M. J.

    2017-04-01

    Losses from the Greenland Ice Sheet (GrIS) have increased sharply in recent years, due to accelerated glacier discharge and increased surface melting. In 2012, 99% of the Greenland ice sheet experienced melt, which was exceptional on centennial timescales, but is expected to occur frequently in the future, as climate warms. Ice albedo is a primary control on melt rates and remotely sensed data shows that the GrIS has darkened substantial in recent decades, due to both inorganic and biological material. This has been particularly marked in south- and central-west Greenland and can lead to the development of positive feedbacks. Consequently, it is important to understand the relationship between melt and surface albedo on the GrIS. Here we use a combination of satellite remote sensing and field data to assess the impact of fine debris on melt rates at Russell Glacier, central-west Greenland. Our field data demonstrate that areas with a greater percentage coverage of fine, largely inorganic debris experienced higher melt rates than in areas with a sparse coverage. However, the relationship between melt and debris cover was highly spatially variable. Furthermore, the debris cover evolved substantially over time and we saw marked changes over a period of a few days. Using ASTER imagery, we show that the spatial extent of debris has expanded markedly in this section of the GrIS during the last decade, which could substantially accelerate melting. However, the complex and variable relationship between debris cover and melt rates highlights the need for further research, in order to accurately forecast its impact on GrIS melt rates.

  13. A modeling study of the effect of runoff variability on the effective pressure beneath Russell Glacier, West Greenland

    Science.gov (United States)

    Fleurian, Basile; Morlighem, Mathieu; Seroussi, Helene; Rignot, Eric; Broeke, Michiel R.; Kuipers Munneke, Peter; Mouginot, Jeremie; Smeets, Paul C. J. P.; Tedstone, Andrew J.

    2016-10-01

    Basal sliding is a main control on glacier flow primarily driven by water pressure at the glacier base. The ongoing increase in surface melting of the Greenland Ice Sheet warrants an examination of its impact on basal water pressure and in turn on basal sliding. Here we examine the case of Russell Glacier, in West Greenland, where an extensive set of observations has been collected. These observations suggest that the recent increase in melt has had an equivocal impact on the annual velocity, with stable flow on the lower part of the drainage basin but accelerated flow above the Equilibrium Line Altitude (ELA). These distinct behaviors have been attributed to different evolutions of the subglacial draining system during and after the melt season. Here we use a high-resolution subglacial hydrological model forced by reconstructed surface runoff for the period 2008 to 2012 to investigate the cause of these distinct behaviors. We find that the increase in meltwater production at low elevation yields a more efficient drainage system compatible with the observed stagnation of the mean annual flow below the ELA. At higher elevation, the model indicates that the drainage system is mostly inefficient and is therefore strongly sensitive to an increase in meltwater availability, which is consistent with the observed increase in ice velocity.

  14. Regional variation of caesium-137 in minke whales ¤Balaenoptera acutorostrata¤ from West Greenland, the Northeast Atlantic and the North Sea

    DEFF Research Database (Denmark)

    Born, E.W.; Dahlgaard, H.; Riget, F.F.

    2002-01-01

    Levels of radioactive caesium (Cs-137) were determined in minke whales (Balaenoptera acutorostrata) from West Greenland, the Northeast Atlantic region and the North Sea. The sample consisted of muscle tissue from 135 minke whales caught in 1998 in 7 different areas: West Greenland, n = 44; East G...

  15. Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland

    OpenAIRE

    2016-01-01

    This is the final version of the article. It first appeared from Elsevier via https://doi.org/10.1016/j.quascirev.2016.01.018 Recent work has confirmed that grounded ice reached the shelf break in central West Greenland during the Last Glacial Maximum (LGM). Here we use a combination of marine sediment-core data, including glacimarine lithofacies and IRD proxy records, and geomorphological and acoustic facies evidence to examine the nature of and controls on the retreat of a major outlet o...

  16. Holocene palaeosols and aeolian activities in the Umimmalissuaq valley, West Greenland

    DEFF Research Database (Denmark)

    Müller, Michael; Thiel, Christine; Kühn, Peter

    2016-01-01

    Aeolian sand sheets and active dunefields preserve an ancient Holocene land surface represented by palaeosols that occur around the present ice margin in the Kangerlussuaq area, West Greenland. To determine the relation between Holocene aeolian activities and periods of soil formation, both subst....... This period was characterised by low but constant aeolian activity. Since aeolian activity intensified after around 300 cal. yr b2k and is still resulting in active dunefields with coarse and medium sand accumulation, the ice margin must have reached its present position at that time....

  17. A new cycle of jökulhlaups at Russell Glacier, Kangerlussuaq, West Greenland

    DEFF Research Database (Denmark)

    Russell, Andrew J.; Carrivick, Jonathan L.; Ingeman-Nielsen, Thomas

    2011-01-01

    Jokulhlaups in 2007 and 2008 from an ice-dammed lake at the northern margin of RussellGlacier, West Greenland, marked the onset of a renewed jokulhlaup cycle after 20 years of stability. Wepresent a record of successive ice-dammed lake drainage events and associated ice-margin dynamicsspanning 25......-based examination of controls on jokulhlaup magnitude and frequency for thissystem. We find that Russell Glacier jokulhlaups have a much higher peak discharge than predicted bythe Clague–Mathews relationship, which we attribute to an unusually short englacial/subglacialrouteway and the presence of a thin ice dam...

  18. Simulated Internal Storage Buildup, Release, and Runoff from Greenland Ice Sheet at Kangerlussuaq, West Greenland

    NARCIS (Netherlands)

    Mernild, S. H.; Liston, G. E.; van den Broeke, M.R.

    2012-01-01

    This study focused on simulated glacier surface conditions (simulated Surface Melt and liquid Precipitation available for supra-, en-, sub-, and proglacial flow processes [after vertical percolation and potential storage within the snowpack] [henceforth SMP]), internal water storage and release, and

  19. Rapid dynamic thinning events during 1985-2010 on Upernavik Isstrøm, West Greenland

    Science.gov (United States)

    Khan, S. A.; Kjaer, K. H.; Korsgaard, N. J.; Wahr, J. M.; Joughin, I. R.; Bamber, J. L.; Csatho, B. M.; van den Broeke, M. R.; Stearns, L. A.; Nielsen, K.; Babonis, G. S.; Hamilton, G. S.; Hurkmans, R. T.; Timm, L. H.

    2011-12-01

    Many glaciers along the southeast and northwest coast of Greenland have accelerated, increasing the ice sheet's contribution to global sea-level rise. Here, we map elevation changes on Upernavik Isstrøm (UI), West Greenland, during 2003-2009 using high-resolution Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data supplemented with altimeter surveys from NASA's Airborne Topographic Mapper (ATM) during 2002-2010. To assess thinning prior to 2002, we analyze aerial photographs from 1985. We document at least two distinct ice loss events characterized by rapid dynamic thinning, increased ice speed, and a retreat of the calving front. The most recent event coincides with the speedup of several glaciers along the northwest coast of Greenland in 2005, and with changes in the rate of mass loss observed using data from the Gravity Recovery and Climate Experiment (GRACE) satellite gravity mission. The first event of increased ice loss could have also taken place along the extended northwest coast. The total dynamic induced ice volume loss on the frontal portion of UI caused by the two events is 45.5 +/- 5.4 km3 (during 1985-2010), while the total melt induced ice volume loss during this same period is 7.4 +/- 1.3 km3.

  20. Simulating Ice-Flow and Calving on Store Glacier, West Greenland, with a 3D Full Stokes Model

    Science.gov (United States)

    Todd, J.; Christoffersen, P.; Zwinger, T.; Luckman, A. J.; Benn, D.

    2015-12-01

    The mass balance and long-term stability of the ice sheets in Greenland and Antarctica depend heavily on the dynamics of their ice-ocean margins. Iceberg calving accounts for the majority of the net annual loss of ice in Antarctica and around half of that from Greenland. Furthermore, climate driven changes to dynamics at these calving margins can be transmitted far inland. Thus, predicting future sea level contribution from the cryosphere requires an improved understanding of calving, and the processes which link it to climate and ice-sheet flow. We present results from a new 3D calving model coupled to a full-Stokes, time evolving glacier dynamic model, implemented for Store Glacier, a 5-km-wide calving glacier in the Uummannaq region of West Greenland, which flows at a rate of 20 m/day at its terminus. The model is developed using the open source finite element package Elmer/Ice, with the criterion that calving occurs when surface and basal crevasses meet. Crevasses open in response to tensile stresses near the terminus and water pressure at the bed. When the model was applied in 2D for the central flowline of Store Glacier, we found that basal topography exerts overarching control on the long term position of the calving front, while ice mélange buttressing allows the seasonal extension of a floating tongue, which collapses in early summer. New results emerging from implementation of calving in a 3D model indicate significant spatial heterogeneity in calving dynamics because the northern half of the terminus is grounded whereas the southern half is floating. This contrasting setting affects calving dynamics, further underlining the importance of geometry and basal topography, and suggesting that lower dimensional calving models may miss important aspects of calving dynamics. Our results also suggest that implementing grounding line dynamics is important for modelling calving, even for glaciers which are, for the most part, firmly grounded.

  1. Monitoring South-West Greenland's ice sheet melt with ambient seismic noise

    Science.gov (United States)

    Mordret, Aurélien; Mikesell, Dylan; Harig, Christopher; Lipovsky, Brad; Prieto, German

    2016-04-01

    The Greenland ice sheet (GIS) accounts for ~ 70% of global ice sheet mass loss and contributes to sea level rise at a rate of 0.7 mm/yr. Therefore, the GIS needs to be carefully monitored. The spaceborne techniques commonly used to monitor the GIS mass balance contain inherent uncertainties. These uncertainties can be reduced by comparing independent datasets and techniques. However, spaceborne methods remain inadequate in the sense that they offer low spatial and/or temporal resolution. This fact highlights the need for other complementary methods to monitor the GIS more accurately and with greater resolution. Here we use a seismic method: the correlation of seismic noise recorded at South-West Greenland seismic stations to show that the GIS seasonal melt produces significant variations of seismic wave speed in the Greenland crust. The amplitudes of the measured velocity variations during 2012-2013 correlate with the total ice plus atmospheric mass variations measured by the GRACE (Gravity Recovery and Climate Experiment) satellite mission. We explain the phase delay between mass maxima and velocity minima ( 50 days) using a non-linear poroelastic model that includes a 55 cm-thick layer of till between the ice sheet and the bedrock. We, thus, interpret the velocity variations as pore pressure variations in the bedrock resulting from the loading and unloading of the overlying glacier and atmosphere. This method provides a new and independent way to monitor in near real-time the first-order state of the GIS, giving new constraints on its evolution and its contribution to the global sea level rise. By increasing the density of seismic stations in the region it will be possible to increase the spatial and temporal resolution of the method and create detailed maps of ice-mass variations across Greenland.

  2. Evidence of Quick-Clay Deposit at Kangerlussuaq, West Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Kirkelund, Gunvor Marie; Jørgensen, Anders Stuhr

    2010-01-01

    eroded and destroyed by the river. In the wake of the catastrophic flood, a previously unknown permafrozen fingrained marine deposit was observed in the erosional bank of the river. Laboratory studies have proven this material to have extremely high sensitivity, with natural water content much higher...... than the liquid limit. The formation has been stabilized by the presence of permafrost in the area, but the combination of erosional energy supplied by the river and the sensitive properties of the material have resulted in quick thaw, destabilization and erosion of the formation. As an effect...

  3. Cenozoic uplift on the West Greenland margin: active sedimentary basins in quiet Archean terranes.

    Science.gov (United States)

    Jess, Scott; Stephenson, Randell; Brown, Roderick

    2016-04-01

    The North Atlantic is believed by some authors to have experienced tectonically induced uplift within the Cenozoic. Examination of evidence, onshore and offshore, has been interpreted to imply the presence of kilometre scale uplift across the margins of the Barents Sea, North Sea, Baffin Bay and Greenland Sea. Development of topography on the West Greenland margin (Baffin Bay), in particular, has been subject to much discussion and dispute. A series of low temperature thermochronological (AFT and AHe) studies onshore and interpretation of seismic architecture offshore have suggested uplift of the entire margin totalling ~3km. However, challenges to this work and recent analysis on the opposing margin (Baffin Island) have raised questions about the validity of this interpretation. The present work reviews and remodels the thermochronological data from onshore West Greenland with the aim of re-evaluating our understanding of the margin's history. New concepts within the discipline, such as effect of radiation damage on Helium diffusivity, contemporary modelling approaches and denudational mapping are all utilised to investigate alternative interpretations to this margins complex post rift evolution. In contrast to earlier studies our new approach indicates slow protracted cooling across much of the region; however, reworked sedimentary samples taken from the Cretaceous Nuussuaq Basin display periods of rapid reheating and cooling. These new models suggest the Nuussuaq Basin experienced a tectonically active Cenozoic, while the surrounding Archean basement remained quiet. Faults located within the basin appear to have been reactivated during the Palaeocene and Eocene, a period of well-documented inversion events throughout the North Atlantic, and may have resulted in subaerial kilometre scale uplift. This interpretation of the margin's evolution has wider implications for the treatment of low temperature thermochronological data and the geological history of the North

  4. Seasonal and interannual phytoplankton production in a sub-arctic tidewater outlet glacier fjord, west Greenland

    DEFF Research Database (Denmark)

    Juul-Pedersen, T.; Arendt, K.; Mortensen, J.

    2015-01-01

    This study describes seasonal patterns and proposes likely drivers of an unusual phytoplankton primary production pattern in the outer-sill region of a tidewater outlet glacierinfluenced fjord (Godthåbsfjord) in SW Greenland. It is based on monthly measurements of pelagic primary production...... in a water column almost fully mixed due to tidal forces at the fjord sill. After the spring bloom, primary production decreased in June, after which a summer bloom of up to 1383 mg C m−2 d−1 built up. This bloom coincided with the development of a pycnocline caused by substantial runoff from the Greenland...... Ice Sheet every year during midsummer. This observation supports a hypothesis that fjord circulation modes and subglacial freshwater discharge, leading to upwelling of nutrient rich water, stimulate primary production in the fjord. Future changes in the timing or magnitude of meltwater runoff from...

  5. Modeling experiments on the deceleration and reactivation of Kangerlussuup Sermusa, West Greenland

    Science.gov (United States)

    Rezvanbehbahani, S.; Stearns, L. A.; van der Veen, C. J.; Catania, G. A.

    2015-12-01

    Seasonal variations in outlet glacier velocity due to basal sliding are well-documented and typically involve acceleration early in the melt season due to enhanced sliding as a result of inefficient drainage of surface water reaching the bed. However, velocity observations from Kangerlussuup Sermusa (KS) in West Greenland contradict this pattern. Instead, ice velocity at KS shows no significant change in early spring compared with the previous winter. This sluggish response of the glacier to spring melt is often followed by an extreme, and short-lived, deceleration. For example, in August 2010, the lower 20 km of the trunk decelerated from about 1600 m a-1 to less than 250 m a-1; this event was followed by a rapid reactivation back to the previous velocity in less than 60 days. Available records since 2006 show that the sequence of steady spring velocity, followed by summer deceleration, and rapid fall reactivation occurs annually; however, the magnitudes of deceleration vary. In this regard, the response of KS to regional environmental forcings is unique compared to its neighboring glaciers. In this study, we investigate whether the unique behavior of KS can be explained by the interaction between changes in basal conditions and the local geometry of the glacier. We model the glacier flow by solving full-Stokes equations using the finite element method in the open-source FEniCS framework. Assuming isothermal ice within the lower trunk, we run experiments on the mechanical properties and boundary conditions of the glacier. These experiments include spatio-temporal changes in basal slipperiness, periodic melt-water influx to the bed, and ice viscosity variations due to changes in melt-water supply to the bed. We also conduct sensitivity analyses on the glacier flow with different ice geometries (e.g. thickness and surface slope) to investigate conditions under which we can produce the unique seasonal behavior of KS. Finally, we assess the impact of the combination

  6. Holocene glacial history of the west Greenland Ice Sheet inferred from cosmogenic exposure ages and threshold lakes

    DEFF Research Database (Denmark)

    Larsen, Nicolaj Krog; Kjaer, K. H.; Colding, Sune Oluf

    2011-01-01

    In this study, we use a combination of 10Be exposure ages and threshold lakes to constrain the ice sheet history in Godthåbs- and Buksefjorden, west Greenland (63-64°N) during the Holocene. The 10Be cosmogenic exposure ages have been used to quantify both the ice retreat and thinning of the west...... Greenland Ice Sheet in 3 transects from the coast to the present ice margin. Preliminary results (n=47) indicate initial deglaciation of coastal areas around 11 ka in concert with existing radiocarbon chronology, followed by a rapid retreat from the outer coast to the present ice margin around 10 ka....... Boulder samples from the highest peaks demonstrate that the ice was warm-based whereas bedrock samples often contain an inherited signal. These results may have implications for other studies in Greenland, which have inferred thin LGM ice based on 10Be ages of bedrock samples. The threshold lakes are used...

  7. Measuring short term velocity changes of Kangilerngata Sermia, west Greenland using a Gamma Portable Radar Interferometer

    Science.gov (United States)

    Kane, E.; Rignot, E. J.; Mouginot, J.; Li, X.; Millan, R.; Fahnestock, M. A.; Nakayama, Y.; Scheuchl, B.

    2016-12-01

    Kangilerngata Sermia, west Greenland, is a 4 km wide marine terminating glacier that experienced rapid retreat from 2005-2010, withdrawing from a stabilizing sill at 150 m depth to its current state, grounded 350 m below sea level. The ice front retreated 2.3 km over a 5 year period with ice speeds increasing to 3x the average rate as the front retreated into deeper water. With a bed that is continuously 200-450 m below sea level for 30 km upstream, this glacier might continue to retreat rapidly for decades to come. We conducted a 16-day field campaign in July 2016 aimed to increase the temporal resolution of ice flow velocity measurements during the peak calving season by using a Gamma Portable Radar Interferometer (GPRI) deployed at 100m elevation about 3 km from the glacier front, scanning the glacier every 3 minutes. In addition we conducted an hydrography survey, collecting a set of 11 CTDs (conductivity, temperature, depth plus dissolved oxygen) about 1 km from the calving front, to estimate the amount of ice melted by the ocean. We compare these results to simulations of ice melt of a calving face using the MITgcm ocean model to help evaluate the model results on one glacier. With the GPRI we form a time series of radar images that show the dynamics of the ocean surface in front of the glacier as a result of wind, sub-glacial water discharge and calving events. We form time series of radar interferograms to analyze the time evolution of glacier speed, especially in relation to calving events, both small and large. Velocity records are used to detect changes in speed, prior, during and post-calving and to determine how long these changes persisted. These results are then analyzed in relation to bed topography (mapped with multi-beam) and tidal cycle. We also compare our results with TerraSAR-X ice velocity maps. We conclude on the impacts of calving events on short-term ice dynamics and implications for the future of this glacier. This work was preformed at

  8. Paleo-Eskimo kitchen midden preservation in permafrost under future climate conditions at Qajaa, West Greenland

    DEFF Research Database (Denmark)

    Elberling, Bo; Matthiesen, Henning; Jørgensen, Christian Juncher

    2011-01-01

    Remains from Paleo-Eskimo cultures are well-documented, but complete preservation is rare. Two kitchen middens in Greenland are known to hold extremely well-preserved organic artefacts. Here, we assess the fate of the Qajaa site in Western Greenland under future climate conditions based on site...... characteristics measured in situ and from permafrost cores. Measurements of thermal properties, heat generation, oxygen consumption and CO2 production show that the kitchen midden can be characterized as peat but produces 4–7 times more heat than natural sediment. An analytical model from permafrost research has...... been applied to assess future thawing of the midden. Results show that the preservation conditions are controlled by freezing temperatures and a high water/ice content limiting the subsurface oxygen availability. Threats to the future preservation are related to thawing followed by drainage...

  9. Chemostratigraphy of Late Cretaceous deltaic and marine sedimentary rocks from high northern palaeolatitudes in the Nuussuaq Basin, West Greenland

    DEFF Research Database (Denmark)

    Lenniger, Marc; Pedersen, Gunver Krarup; Bjerrum, Christian J.

    The Nuussuaq Basin in the Baffin Bay area in West Greenland formed as a result of the opening of the Labrador Sea in Late Mesozoic to Early Cenozoic times. The first rifting and the development of the Nuussuaq Basin took place during the Early Cretaceous and was followed by a second rifting phase...

  10. The effect of sea-ice loss on beluga whales (Delphinapterus leucas) in West Greenland

    DEFF Research Database (Denmark)

    Heide-Jørgensen, M.P.; Laidre, K.L.; Simon, Malene Juul

    2009-01-01

    An aerial survey was conducted to estimate the abundance of belugas (Delphinapterus leucas) on their wintering ground in West Greenland in March-April 2006 and 2008. The survey was conducted as a double platform aerial line transect survey, and sampled approximately 17% of the total survey area o...

  11. Modeling of ocean-induced ice melt rates of five west Greenland glaciers over the past two decades

    NARCIS (Netherlands)

    Rignot, E.; Xu, Y.; Menemenlis, D.; Mouginot, J.; Scheuchl, B.; Li, X.; Morlighem, M.; Seroussi, H.; van den Broeke, M.|info:eu-repo/dai/nl/073765643; Fenty, I.; Cai, C.; An, L.; de Fleurian, B.

    2016-01-01

    High-resolution, three-dimensional simulations from the Massachusetts Institute of Technology general circulation model ocean model are used to calculate the subaqueous melt rate of the calving faces of Umiamako, Rinks, Kangerdlugssup, Store, and Kangilerngata glaciers, west Greenland, from 1992 to

  12. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: A lead isotope study of an Archaean gold prospect in the Attu region, Nagssugtoqidian orogen, West Greenland

    Directory of Open Access Journals (Sweden)

    Stendal, Henrik

    2006-12-01

    Full Text Available This paper presents a lead isotope investigation of a gold prospect south of the village Attu in the northern part of the Nagssugtoqidian orogen in central West Greenland. The Attu gold prospect is a replacement gold occurrence, related to a shear/mylonite zone along a contact between orthogneissand amphibolite within the Nagssugtoqidian orogenic belt. The mineral occurrence is small, less than 0.5 m wide, and can be followed along strike for several hundred metres. The mineral assemblage is pyrite, chalcopyrite, magnetite and gold. The host rocks to the gold prospect are granulite facies ‘brown gneisses’ and amphibolites. Pb-isotopic data on magnetite from the host rocks yield an isochron in a 207Pb/204Pb vs. 206Pb/204Pb diagram, giving a date of 3162 ± 43 Ma (MSWD = 0.5. This date is interpreted to represent the age of the rocks in question, and is older than dates obtained from rocks elsewhere within the Nagssugtoqidian orogen. Pb-isotopic data on cataclastic magnetite from the shear zone lie close to this isochron, indicating a similar origin. The Pb-isotopic compositions of the ore minerals are similar to those previously obtained from the close-by ~2650 Ma Rifkol granite, and suggest a genetic link between the emplacement of this granite and the formation of the ore minerals in the shear/mylonite zone. Consequently, the age of the gold mineralisation is interpreted tobe late Archaean.

  13. Rise in central west Greenland surface melt unprecedented over the last three centuries

    Science.gov (United States)

    Trusel, Luke; Das, Sarah; Osman, Matthew; Evans, Matthew; Smith, Ben; McConnell, Joe; Noël, Brice; van den Broeke, Michiel

    2017-04-01

    Greenland Ice Sheet surface melting has intensified and expanded over the last several decades and is now a leading component of ice sheet mass loss. Here, we constrain the multi-century temporal evolution of surface melt across central west Greenland by quantifying layers of refrozen melt within well-dated firn and ice cores collected in 2014 and 2015, as well as from a core collected in 2004. We find significant agreement among ice core, satellite, and regional climate model melt datasets over recent decades, confirming the fidelity of the ice core melt stratigraphy as a reliable record of past variability in the magnitude of surface melt. We also find a significant correlation between the melt records derived from our new 100-m GC-2015 core (2436 m.a.s.l.) and the older (2004) 150-m D5 core (2472 m.a.s.l.) located 50 km to the southeast. This agreement demonstrates the robustness of the ice core-derived melt histories and the potential for reconstructing regional melt evolution from a single site, despite local variability in melt percolation and refreeze processes. Our array of upper percolation zone cores reveals that although the overall frequency of melt at these sites has not increased, the intensification of melt over the last three decades is unprecedented within at least the last 365 years. Utilizing the regional climate model RACMO 2.3, we show that this melt intensification is a nonlinear response to warming summer air temperatures, thus underscoring the heightened sensitivity of this sector of Greenland to further climate warming. Finally, we examine spatial correlations between the ice core melt records and modeled melt fields across the ice sheet to assess the broader representation of each ice core record. This analysis reveals wide-ranging significant correlations, including to modeled meltwater runoff. As such, our ice core melt records may furthermore offer unique, observationally-constrained insights into past variability in ice sheet mass loss.

  14. Multi-decadal and seasonal variability of dust observations in West Greenland.

    Science.gov (United States)

    Bullard, Joanna E.; Mockford, Tom

    2017-04-01

    Since the early 1900s expedition records from west Greenland have reported local dust storms. The Kangerlussuaq region, near the inland ice, is dry (mean annual precipitation WMO weather codes 6 (dust haze), 7 (raised dust or sand) and 9 (distant or past dust storm) and associated wind data. The 70-year average number of dust observations days is 5 per year but variable ranging from 0 observations to 23 observations in 1985. Over the past 7 decades the number of dust days has increased from 75 in 1995-2004 and 2005-2015. The seasonality of dust observations has remained consistent throughout most of the period. Dust days occur all year round but are most frequent in May-June and September-October and are associated with minimum snow cover and glacial meltwater-driven sediment supply to the outwash plains during spring and fall flood events. Wind regime is bimodal dominated by katabatic winds from the northeast, which are strongest and most frequent during winter months (Nov-Jan), with less frequent, southwesterly winds generated by Atlantic storms mostly confined to spring (May, June). The southwesterly winds are those most likely to transport dust onto the Greenland ice sheet.

  15. Spatial Variability in Surface Elevation Changes of Central-West Greenland Outlet Glaciers

    Science.gov (United States)

    Felikson, D.; Catania, G. A.; Kjaer, K. H.; Korsgaard, N. J.; Stearns, L. A.; Nash, J. D.; Shroyer, E.; Sutherland, D.; Walker, R. T.

    2014-12-01

    The mass balance of the Greenland ice sheet (GrIS) is, in part, governed by the dynamics of ocean-terminating glaciers. GRACE data reveal that along the central-west coast of the GrIS, overall ice loss has been accelerating since 2007. However, we do not know the physical processes controlling the loss here, and the changes observed are not uniform in this region; several glaciers have gone through periods of slow-down in the recent past. To address these uncertainties, we have performed ~30-year DEM differences of outlet glaciers in the region. Present-day DEMs have been created from WorldView-1 and -2 (WV) stereo imagery acquired in 2012 and 2013 using the AMES Stereo Pipeline. A 1985 DEM was created from a Greenland aerial photo survey. The DEM differences between the present-day WV DEMs and the 1985 aerial photo DEM show clearly that spatial variability in the surface elevation and terminus position changes of the glaciers in the region has been ongoing for the last ~30 years. We examine this variability in the context of ocean temperature and surface mass balance estimates to yield further insight into the external controls on these glaciers.

  16. Effect of acidification on an Arctic phytoplankton community from Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Thoisen, Christina; Riisgaard, Karen; Lundholm, Nina

    2015-01-01

    . Our findings show that coastal phytoplankton from Disko Bay is naturally exposed to pH fluctuations exceeding the experimental pH range used in most ocean acidification studies. We emphasize that studies on ocean acidification should include in situ pH before assumptions on the effect of acidification...... on marine organisms can be made. KEY WORDS: Ocean acidification · Coastal · Arctic phytoplankton · Growth rate · pH · CO2 · DIC......ABSTRACT: Long-term measurements (i.e. months) of in situ pH have not previously been reported from the Arctic; this study shows fluctuations between pH 7.5 and 8.3 during the spring bloom 2012 in a coastal area of Disko Bay, West Greenland. The effect of acidification on phytoplankton from...

  17. Effect of acidification on an Arctic phytoplankton community from Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Thoisen, Christina; Riisgaard, Karen; Lundholm, Nina;

    2015-01-01

    . Our findings show that coastal phytoplankton from Disko Bay is naturally exposed to pH fluctuations exceeding the experimental pH range used in most ocean acidification studies. We emphasize that studies on ocean acidification should include in situ pH before assumptions on the effect of acidification...... on marine organisms can be made. KEY WORDS: Ocean acidification · Coastal · Arctic phytoplankton · Growth rate · pH · CO2 · DIC......ABSTRACT: Long-term measurements (i.e. months) of in situ pH have not previously been reported from the Arctic; this study shows fluctuations between pH 7.5 and 8.3 during the spring bloom 2012 in a coastal area of Disko Bay, West Greenland. The effect of acidification on phytoplankton from...

  18. Twenty-one years of mass balance observations along the K-transect, West Greenland

    Directory of Open Access Journals (Sweden)

    R. S. W. van de Wal

    2012-08-01

    Full Text Available A 21-yr record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990–2011. Data are available at eight sites along a transect over an altitude range of 380–1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 × 10−3 m w.e. m−1, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower three sites within 10 km of the margin up to an elevation of 700 m experience a significant increasing trend in the ablation over the entire period. Data are available at: doi:10.1594/PANGAEA.779181.

  19. Twenty-one years of mass balance observations along the K-transect, West Greenland

    Directory of Open Access Journals (Sweden)

    R. S. W. van de Wal

    2012-05-01

    Full Text Available A 21-yr record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990–2011. Data are available at 8 sites along a transect over an altitude range of 390–1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 × 10−3 m w.e. m−1, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower 3 sites within 10 km of the margin experience a significant increasing trend in the ablation over the entire period. Data are available at: http://doi.pangaea.de/10.1594/PANGAEA.779181.

  20. Antler possession by west Greenland female caribou in relation to population characteristics

    Directory of Open Access Journals (Sweden)

    Henning Thing

    1986-06-01

    Full Text Available The frequency of antlerless adult female caribou (Rangifer tarandus groenlandicus was studied in four separate populations in west Greenland. Between the herds antlerlessness varied from 21% to 79%. An inverse relationship between winter range quality and percentage of unantlered cows is demonstrated. Relationship between calf percentage and maternal antler status was studied in one population and antlerless cows showed higher reproductive rate than antlered ones. In another population antlerless cows were almost absent outside the calving area. Calves of antlerless mothers were more susceptible to diseases and had significantly higher summer mortality than other calves, 42% and 27% respectively. The relative importance of factors influencing antler development under various environmental conditons are assessed and a close relationship between antlerlessness, physical condition, lactation, and length of period between calving and midsummer is discussed.

  1. Mapping ice-bonded permafrost with electrical methods in Sisimiut, West Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas

    2006-01-01

    Permafrost delineation and thickness determination is of great importance in engineering related projects in arctic areas. In this paper, 2D geoelectrical measurements are applied and evaluated for permafrost mapping in an area in West Greenland. Multi-electrode resistivity profiles (MEP) have been...... collected and are compared with borehole information. It is shown that the permafrost thickness in this case is grossly overestimated by a factor of two to three. The difference between the inverted 2D resistivity sections and the borehole information is explained by macro-anisotropy due to the presence...... of horizontal ice-lenses in the frozen clay deposits. It is concluded that where the resistivity method perform well for lateral permafrost mapping, great care should be taken in evaluating permafrost thickness based on 2D resistivity profiles alone. Additional information from boreholes or other geophysical...

  2. Ice stratigraphy at the Pakitsoq ice margin, West Greenland, derived from gas records

    DEFF Research Database (Denmark)

    Schaefer, H.; Petrenko, V. V.; Brook, E. J.;

    2009-01-01

    Horizontal ice-core sites, where ancient ice is exposed at the glacier surface, offer unique opportunities for paleo-studies of trace components requiring large sample volumes. Following previous work at the Pakitsoq ice margin in West Greenland, we use a combination of geochemical parameters...... measured in the ice matrix (delta O-18(ice)) and air occlusions (delta O-18(atm), delta N-15 of N-2 and methane concentration) to date ice layers from specific climatic intervals. The data presented here expand our understanding of the stratigraphy and three-dimensional structure of ice layers outcropping...... at Pakitsoq. Sections containing ice from every distinct climatic interval during Termination I, including Last Glacial Maximum, Bolling/Allerod, Younger Dryas and the early Holocene, are identified. In the early Holocene, we find evidence for climatic fluctuations similar to signals found in deep ice cores...

  3. Significance of the late Archaean granulite facies terrain boundaries, Southern West Greenland

    Science.gov (United States)

    Friend, C. R. L.; Nutman, A. P.; Mcgregor, V. R.

    1988-01-01

    Three distinct episodes and occurrences of granulite metamorphism in West Greenland are described: (1) the oldest fragmentary granulites occur within the 3.6-Ga Amitsoq gneisses and appear to have formed 200 Ma after the continental crust in which they lie (Spatially associated rapakivi granites have zircon cores as old as 3.8 Ga, but Rb-Sr, whole-rock Pb-Pb, and all other systems give 3.6 Ga, so these granulites apparently represent a later metamorphic event); (2) 3.0-Ga granulites of the Nordlandet Peninsula NW of Godthaab, developed immediately after crustal formation in hot, dry conditions, are carbonate-free, associated with voluminous tonalite, and formed at peak metamorphic conditions of 800 C and 7 to 8 kbar (Synmetamorphic trondhjemite abounds and the activity of H2O has been indicated by Pilar to have varied greatly); and (3) 2.8-Ga granulites south of Godthaab, lie to the south of retrogressed amphibolite terranes. Prograde amphibolite-granulite transitions are clearly preserved only locally at the southern end of this block, near Bjornesund, south of Fiskenaesset. Progressively deeper parts of the crust are exposed from south to north as a major thrust fault is approached. Characteristic big hornblende pegmatites, which outcrop close to the thrust in the east, have been formed by replacement of orthopyroxene. Comparable features were not seen in South Indian granulites. It was concluded that no one mechanism accounts for the origin of all granulites in West Greenland. Various processes have interacted in different ways, and what happened in individual areas must be worked out by considering all possible processes.

  4. Size and trends of the bowhead whale, beluga and narwhal stocks wintering off West Greenland

    Directory of Open Access Journals (Sweden)

    MP Heide-Jørgensen

    2002-07-01

    Full Text Available To assess the size and trends of the abundance of the bowhead whale (Balaena mysticetus, the beluga, or white whale (Delphinapterus leucas, and the narwhal (Monodon monoceros visual aerial surveys were conducted in West Greenland in March 1998 and 1999. An estimated 49 bowhead whales (95% CI: 13 to 188 were present at the surface in 1998. Data from land-based observations enabled correction for bowhead whales that were not available at the surface to be seen during the survey. By applying a rounded average of 80% (SE=3 for submergence an estimate of 246 bowhead whales (95% CI: 62 to 978 in 1998 was obtained. The 76 and 47 sightings of beluga pods in 1998 and 1999, respectively, had distributions similar to those of previous surveys with the highest concentration at the northern edge of the northern part of Store Hellefiskebanke. No belugas were seen in the southernmost area between Maniitsoq and Paamiut. The index estimate of the abundance of belugas comparable with previous surveys was 929 (95% CI: 563 to 1,533 in 1998 and 735 (95% CI: 436 to 1,239 in 1999. When analysing the sightings as a line-transect survey and correcting for whales that were either submerged or at the surface but missed by the observers an estimated 7,941 (95% CI: 3,650 to 17,278 belugas wintered in West Greenland in 1998-1999. The uncorrected estimate of narwhal abundance was 524 (95% CI: 214 to 1,284 and correcting for the same biases as for the belugas gives a total abundance of 2,861 (95% CI: 954 to 8,578 narwhals in 1998-1999.

  5. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Origin and evolution of the Kangâmiut mafic dyke swarm, West Greenland

    Directory of Open Access Journals (Sweden)

    Lesher, Charkes E.

    2006-12-01

    Full Text Available The Kangâmiut dyke swarm in West Greenland intruded Archaean terrains at 2.04 Ga, and its northern portion was subsequently metamorphosed to granulite facies during the Nagssugtoqidian orogeny(c. 1.8 Ga. Mineral and whole-rock major and trace element compositions show that the parental magmas for the dyke swarm differentiated by the fractionation of olivine, clinopyroxene, plagioclase and late stage Fe-Ti oxides. Petrographical observations and the enrichment of K2O during differentiation argue that hornblende was not an important fractionating phase. Field observations suggest emplacement at crustal levels above the brittle–ductile transition, and clinopyroxene geothermobarometry constrains dyke emplacement depths to less than 10 km. Granulite facies metamorphism of the Kangâmiut dykes and their host rocks in the northern portion of the swarm requires subsequent burial to c. 30 km, related to roughly 20 km of crustal thickening between the time of dyke emplacement and peak metamorphism during the Nagssugtoqidian orogeny. Kangâmiut dykes are characterised by low Ba/La ratios (12 ±5, and high Nb/La ratios (0.8 ±0.2, compared to subduction relatedbasalts (Ba/La c. 25; Nb/La c. 0.35. These geochemical characteristics argue that the Kangâmiut dykes are not related to subduction processes. Forward modelling of rare-earth element data requires that primitive magmas for the Kangâmiut dykes originated from a moderately depleted mantle source with a mantle potential temperature of c. 1420°C. The inferred potential temperature is consistent with potential temperature estimates for ambient mantle at 2.0 Ga derived from secular cooling models and continental freeboard constraints. The geochemistry and petrology of the Kangâmiut dykes support a model that relates the dyke activity to passive rifting of the proposed Kenorland supercontinent rather than to mantle plume activity or subduction.

  6. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Magnetic anomalies and metamorphic boundaries in the southern Nagssugtoqidian orogen, West Greenland

    Directory of Open Access Journals (Sweden)

    Korstgård, John A.

    2006-12-01

    Full Text Available Within the southern Nagssugtoqidian orogen in West Greenland metamorphic terrains of both Archaean and Palaeoproterozoic ages occur with metamorphic grade varying from low amphibolites facies to granulite facies. The determination of the relative ages of the different metamorphic terrains is greatly aided by the intrusion of the 2 Ga Kangâmiut dyke swarm along a NNE trend. In Archaean areas dykes cross-cut gneiss structures, and the host gneisses are in amphibolite to granulite facies. Along Itilleq strong shearing in an E–W-oriented zone caused retrogression of surrounding gneisses to low amphibolite facies. Within this Itivdleq shear zone Kangâmiut dykes follow the E–W shear fabrics giving the impression that dykes were reoriented by the shearing. However, the dykes remain largely undeformed and unmetamorphosed, indicating that the shear zone was established prior to dyke emplacement and that the orientation of the dykes here was governed by the shear fabric. Metamorphism and deformation north of Itilleq involve both dykes and host gneisses, and the metamorphic grade is amphibolite facies increasing to granulite facies at the northern boundary of the southern Nagssugtoqidian orogen. Here a zone of strong deformation, the Ikertôq thrust zone, coincides roughly with the amphibolite–granulite facies transition. Total magnetic field intensity anomalies from aeromagnetic data coincide spectacularly with metamorphic boundaries and reflect changes in content of the magnetic minerals at facies transitions. Even the nature of facies transitions is apparent. Static metamorphic boundaries are gradual whereas dynamic boundaries along deformation zones are abrupt.

  7. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Evolution of Neoarchaean supracrustal belts at the northern margin of the North Atlantic Craton, West Greenland

    Directory of Open Access Journals (Sweden)

    Stensgaard, Bo Møller

    2006-12-01

    Full Text Available The Archaean North Atlantic Craton of West Greenland collided at c. 1.9 Ga with a lesser-known Archaean craton to the north, to form the Nagssugtoqidian orogen. The Palaeoproterozoic metamorphic grade and strain intensity decrease northward through the orogen, allowing investigation of the reworked Archaean components in its northern part. Two Archaean supracrustal belts in this region – the Ikamiut and Kangilinaaq belts – are investigated here using field mapping, aeromagnetic data, zircon geochronology, and geochemistry. Both belts comprise quartzo-feldspathic and pelitic metasedimentary rocks, amphibolite, and minor calc-silicate rocks, anorthosite and ultramafic rocks. Pb-Pb and U-Pb dating of detrital zircons and host orthogneisses suggest deposition at c. 2800 Ma (Kangilinaaq belt and after 2740 Ma (Ikamiut belt; both belts have zircons with Neoarchaean metamorphic rims. Metasedimentary rocks and orthogneisses at Ikamiut share similar steep REE signatures with strong LREE enrichment, consistent with local derivation of the sediment and deposition directly onto or proximal to the regional orthogneiss precursors. Zircon age data from Kangilinaaq indicate both local and distal sources for the sediment there. Geochemical data for Kangilinaaq amphibolites indicate bimodal, mixed felsic–mafic source rocks with island-arc basaltic affinities, consistent with a shelf or arc setting. Both belts experienced a similar tectono-metamorphic history involving Neoarchaean amphibolite facies peak metamorphism at c. 2740–2700 Ma, possibly due to continued emplacement of tonalitic and granodioritic magmas. Nagssugtoqidian lower amphibolite facies metamorphism at c. 1850 Ma was associated with development of the large-scale F2 folds and shear zones that control the present outcrop pattern. The observed differences in the sources of the Kangilinaaq and Ikamiut belts and their shared post-Archaean history suggest they were formed in different

  8. The Detection of Subglacial Water, and Its Distribution in Greenland

    Science.gov (United States)

    Oswald, G. K.

    2016-12-01

    Three methods have been used to detect or predict the presence of subglacial water in Antarctica, Greenland and elsewhere. These are (a) coring to bedrock, (b) ice-penetrating radar and (c) numerical modeling. Since the 1960s radar measurements have provided the greatest volume of results, including the extensive distribution of subglacial melt lakes in Antarctica. Drilling of course is expensive and narrowly focused, and modeling is only as good as the theory behind it. However in recent years concerns have been expressed that radar measurements themselves are only as good as the models used to compensate for dielectric attenuation in propagation through the ice. In this paper we will show that radar, properly processed, succeeds in resolving thawed and frozen ice sheet bed distributions beneath the GrIS. This is based on the use of additional and inherent aspects of the radar signal information content, which demonstrate that indeed the bed reflection can be measured, without confusion by uncertain aspects of modeling englacial attenuation. We go on to illustrate the actual distribution of subglacial water in Greenland. We relate it to models being developed to predict the future behaviour of the GrIS, and we highlight areas that may benefit from finer-grained investigation of topography or internal stress.

  9. Towards multi-decadal to multi-millennial ice core records from coastal west Greenland ice caps

    Science.gov (United States)

    Das, Sarah B.; Osman, Matthew B.; Trusel, Luke D.; McConnell, Joseph R.; Smith, Ben E.; Evans, Matthew J.; Frey, Karen E.; Arienzo, Monica; Chellman, Nathan

    2017-04-01

    The Arctic region, and Greenland in particular, is undergoing dramatic change as characterized by atmospheric warming, decreasing sea ice, shifting ocean circulation patterns, and rapid ice sheet mass loss, but longer records are needed to put these changes into context. Ice core records from the Greenland ice sheet have yielded invaluable insight into past climate change both regionally and globally, and provided important constraints on past surface mass balance more directly, but these ice cores are most often from the interior ice sheet accumulation zone, at high altitude and hundreds of kilometers from the coast. Coastal ice caps, situated around the margins of Greenland, have the potential to provide novel high-resolution records of local and regional maritime climate and sea surface conditions, as well as contemporaneous glaciological changes (such as accumulation and surface melt history). But obtaining these records is extremely challenging. Most of these ice caps are unexplored, and thus their thickness, age, stratigraphy, and utility as sites of new and unique paleoclimate records is largely unknown. Access is severely limited due to their high altitude, steep relief, small surface area, and inclement weather. Furthermore, their relatively low elevation and marine moderated climate can contribute to significant surface melting and degradation of the ice stratigraphy. We recently targeted areas near the Disko Bay region of central west Greenland where maritime ice caps are prevalent but unsampled, as potential sites for new multi-decadal to multi-millennial ice core records. In 2014 & 2015 we identified two promising ice caps, one on Disko Island (1250 m. asl) and one on Nuussuaq Peninsula (1980 m. asl) based on airborne and ground-based geophysical observations and physical and glaciochemical stratigraphy from shallow firn cores. In spring 2015 we collected ice cores at both sites using the Badger-Eclipse electromechanical drill, transported by a medley

  10. Recent changes in North West Greenland climate documented by NEEM shallow ice core data and simulations, and implications for past temperature reconstructions

    Science.gov (United States)

    Masson-Delmotte, V.; Steen-Larsen, H. C.

    2014-12-01

    Stack records of accumulation, d18O and deuterium excess were produced from up to 4 shallow ice cores at NEEM (North-West Greenland), spanning 1724-2007 and updated to 2011 using pit water stable isotope data. Signal-to-noise ratio is high for d18O (1.3) and accumulation (1.2) but is low for deuterium excess (0.4). No long-term trend is observed in the accumulation record. By contrast, NEEM d18O shows multi-decadal increasing trends in the late 19th century and since the 1980s. Decadal d18O and accumulation variability is in phase with Atlantic Multi-decadal Oscillation indices, and enhanced at the beginning of the 19th century. Large-scale spatial coherency is detected between NEEM and other Greenland ice core and temperature records, strongest for North-West Greenland d18O and summer South-West coastal temperature instrumental records. The strength of correlations with the North Atlantic Oscillation is smaller than in central or south Greenland. The strongest positive d18O values are recorded at NEEM in 2010, followed by 1928, while maximum accumulation occurs in 1933. The coldest/driest decades are depicted at NEEM in 1815-1825 and 1836-1836. The spatial structure of these warm/ wet years and cold/dry decades is investigated using all available Greenland ice cores. During the period 1958-2011, the NEEM accumulation and d18O records are highly correlated with simulated precipitation, temperature and d18O from simulations performed with MAR, LMDZiso and ECHAM5iso atmospheric models, nudged to atmospheric reanalyses. Model-data agreement is better using ERA reanalyses than NCEP/NCAR and 20CR ones. Model performance is poor for deuterium excess. Gridded temperature reconstructions, instrumental data and model outputs at NEEM are used to estimate the d18O-temperature relationship for the strong warming period in 1979-2007. The estimated slope of this relationship is 1.1±0.2‰ per °C, about twice larger than previously used to estimate last interglacial temperature

  11. Basin-Wide Mass Balance of Jakobshavn Isbræ (West Greenland) during 1880-2100

    Science.gov (United States)

    Muresan, I. S.; Khan, S. A.; Aschwanden, A.; Langen, P. L.; Khroulev, C.; Box, J. E.; Kjaer, K. H.

    2015-12-01

    Greenland's main outlet glaciers have more than doubled their contribution to global sea-level rise over the past decade through acceleration of ice discharge. Jakobshavn Isbræ (JI) in west Greenland is the largest outlet glacier in terms of drainage area.Here we use a 3-D modeling approach to study the mechanisms controlling dynamic changes at the terminus of JI over a period of 220 years. Over 100 simulations are performed with different sets of parameters where the calving fronts and the grounding lines are free to evolve in time under atmospheric and oceanic forcing. We find that the thinning and the retreat that starts at the calving front and then propagates upstream is mostly controlled by a loss of resistive stresses at the terminus through glacier dynamics induced calving rather than by changes in oceanic temperatures. Three major accelerations are identified in 1928, 1998 and in the summer of 2003. The acceleration which started in 1928 slowly faded by 1948, while the accelerations in 1998 and 2003 sustain the high velocities observed at JI in the last decade. Further, we find that under atmospheric RCP 4.5 and RCP 8.5 forcing (no RCP ocean forcing included), an increase in ocean temperatures of just 0.7 °C (relative to 1880-2012) is enough to trigger a collapse of the JI's southern tributary by 2050 which further destabilizes JI and unleashes a major glacial collapse of ~25 km. JI's contribution to SLR is found to be ~2.8 mm (~1014 Gt) for the period 1880 to 2014, from which the contribution between 1997 to 2014 represents 27 %. By the end of the century contributions to SLR as high as ~11 mm (~4000 Gt under RCP 8.5 and almost 300% increase relative to 1880-2014) can be expected from Jakobshavn Isbræ only. Our choice of ice sheet model comprises the Parallel Ice Sheet Model (PISM).

  12. Oil seepage onshore West Greenland: evidence of multiple source rocks and oil mixing

    Energy Technology Data Exchange (ETDEWEB)

    Bojesen-Koefoed, J.; Christiansen, F.G.; Nytoft, H.P.; Pedersen, A.K.

    1998-08-01

    Widespread oil seepage and staining are observed in lavas and hyaloclastites in the lower part of the volcanic succession on northwestern Disko and western Nuussuaq, central West Greenland. Chemical analyses suggest the existence of several petroleum systems in the underlying Cretaceous and Paleocene fluviodeltaic to marine sediments. Seepage and staining commonly occur within vesicular lava flow tops, and are often associated with mineral veins (mostly carbonates) in major fracture systems. Organic geochemical analyses suggest the existence of at least five distinct oil types: (1) a waxy oil, which on the basis of the presence of abundant angiosperm biological markers, is interpreted as generated from Paleocene mud-stones (the `Marraat type`); (2) a waxy oil, probably generated from coals and shales of the Cretaceous Atane formation (the `Kuugannguaq type`); (3) a low to moderately waxy oil containing 28,30-bisnorhopane, and abundant C{sub 27}-diasteranes and regular steranes (the `Itilli type`), possibly generated from presently unknown Cenomanian-Turonian marine modstones; (4) a low wax oil of marine, possibly lagoonal/saline lacustrine origin, containing ring-A methylated steranes and a previously unknown series of extended 28-norhopanes (the `Eqalulik type`); (5) a waxy oil with biological marker characteristics different from both the Kuugannguaq and Marraat oil types (the `Niaqornaarsuk type`), probably generated from Campanian mud-stones. The presence of widespread seepage and staining originating from several source rocks is encouraging for exploration in basins both on- and offshore western Greenland, where the existence of prolific source rocks has previously been the main exploration risk. (au) EFP-96. 34 refs.

  13. Arctic Outflow West Of Greenland: Nine Years Of Volume And Freshwater Transports From Observations In Davis Strait

    Science.gov (United States)

    Curry, B.; Lee, C.; Petrie, B.; Moritz, R. E.; Kwok, R.

    2014-12-01

    Recent Arctic changes suggest alterations in the export of freshwater from the Arctic to the North Atlantic, with conceivable impacts on the Atlantic Meridional Overturning circulation. Approximately 50% of the Arctic outflow exits west of Greenland, traveling through the Canadian Arctic Archipelago (CAA) and into Baffin Bay before crossing Davis Strait. The CAA outflow contributes over 50% of the net southward freshwater outflow through Davis Strait. The remainder is deeper outflow from Baffin Bay, flow from the West Greenland Current and runoff from West Greenland and CAA glaciers. Since September 2004, an observational program in Davis Strait has quantified volume and freshwater transport variability. The year-round program includes velocity, temperature and salinity measurements from 15 moorings spanning the full width (330 km) of the strait accompanied by autonomous Seagliders surveys (average profile separation = 4 km) and autumn ship-based hydrographic sections. Over the shallow Baffin Island and West Greenland shelves, moored instrumentation provides temperature and salinity measurements near the ice-ocean interface. From 2004-2013, the average net volume and liquid freshwater transports are -1.6 ± 0.2 Sv, -94 ± 7 mSv, respectively (salinity referenced to 34.8 and negative indicates southward transport); sea ice contributes an additional -10 ± 1 mSv. Over this period, volume and liquid freshwater transports show significant interannual variability and no clear trends, but a comparison with reanalyzed 1987-90 data indicate a roughly 40% decrease in net southward liquid volume transport and a corresponding an almost 30% decrease in freshwater transport. Connections between the Arctic are also captured, e.g., a unique yearlong Davis Strait freshening event starting September 2009 that was likely driven by an earlier freshening (January 2009 - April/May 2010) in the Canadian Arctic. The Davis Strait autumn 2009 salinity minimum was fresher (by about 0

  14. Mineral nutrition and alimentary pools in muskoxen and caribou on the Angujaartorfiup Nunaa range in West Greenland

    Directory of Open Access Journals (Sweden)

    Hans Staaland

    1999-04-01

    Full Text Available Minerals (Na, K, Cl, Ca, P, Mg and crude protein concentrations as well as total contents were measured throughout the alimentary tract of muskoxen and caribou from Angujaatorfiup Nunaa range, Søndre Strømfjord area in West Greenland. The muskoxen had significantly higher K concentrations in the caecum and proximal colon than the caribou. Caribou collected during the summer season had the highest Mg concentrations throughout the alimentary tract. In both species water, Na, K and CI concentrations decreased through the distal part of the alimentary system whereas Ca, Mg, P and crude protein concentrations increased. The muskoxen had relatively larger mineral pools and total content in the omasum than the caribou, and the caribou relatively larger mineral pools (except K and CI and total content in the caecum. Higher concentrations of Mg in the alimentary tract of the caribou than the muskoxen during the summer could also indicate that the caribou feed more on herbs with high concentrations of Mg. The data does also indicate that both the caribou and the muskoxen are living in an area where high intakes of minerals from both vegetation and mineral licks are possible. Based on the present study the muskoxen is apparently a typical grazer whereas the caribou is more like a concentrate selector.

  15. Surface water hydrology and the Greenland Ice Sheet

    Science.gov (United States)

    Smith, L. C.; Yang, K.; Pitcher, L. H.; Overstreet, B. T.; Chu, V. W.; Rennermalm, A. K.; Cooper, M. G.; Gleason, C. J.; Ryan, J.; Hubbard, A.; Tedesco, M.; Behar, A.

    2016-12-01

    Mass loss from the Greenland Ice Sheet now exceeds 260 Gt/year, raising global sea level by >0.7 mm annually. Approximately two-thirds of this total mass loss is now driven by negative ice sheet surface mass balance (SMB), attributed mainly to production and runoff of meltwater from the ice sheet surface. This new dominance of runoff as a driver of GrIS total mass loss will likely persist owing to anticipated further increases in surface melting, reduced meltwater storage in firn, and the waning importance of dynamical mass losses (ice calving) as the ice sheets retreat from their marine-terminating margins. It also creates the need and opportunity for integrative research pairing traditional surface water hydrology approaches with glaciology. As one example, we present a way to measure supraglacial "runoff" (i.e. specific discharge) at the supraglacial catchment scale ( 101-102 km2), using in situ measurements of supraglacial river discharge and high-resolution satellite/drone mapping of upstream catchment area. This approach, which is standard in terrestrial hydrology but novel for ice sheet science, enables independent verification and improvement of modeled SMB runoff estimates used to project sea level rise. Furthermore, because current SMB models do not consider the role of fluvial watershed processes operating on the ice surface, inclusion of even a simple surface routing model materially improves simulations of runoff delivered to moulins, the critical pathways for meltwater entry into the ice sheet. Incorporating principles of surface water hydrology and fluvial geomorphology and into glaciological models will thus aid estimates of Greenland meltwater runoff to the global ocean as well as connections to subglacial hydrology and ice sheet dynamics.

  16. Seasonal and interannual phytoplankton production in a sub-arctic tidewater outlet glacier fjord, west Greenland

    DEFF Research Database (Denmark)

    Juul-Pedersen, T.; Arendt, K.; Mortensen, J.;

    2015-01-01

    and hydrographic conditions during a 7 yr period. Total annual primary production during 2005 to 2012 was between 84.6 and 139.1 g C m−2 yr−1. Two phytoplankton blooms of similar magnitude reoccur in the fjord every year. A ‘classical’ spring bloom of up to 1743 mg C m−2 d−1 occurred in late April/early May...... in a water column almost fully mixed due to tidal forces at the fjord sill. After the spring bloom, primary production decreased in June, after which a summer bloom of up to 1383 mg C m−2 d−1 built up. This bloom coincided with the development of a pycnocline caused by substantial runoff from the Greenland...

  17. Biogeochemical data from terrestrial and aquatic ecosystems in a periglacial catchment, West Greenland

    Science.gov (United States)

    Lindborg, Tobias; Rydberg, Johan; Tröjbom, Mats; Berglund, Sten; Johansson, Emma; Löfgren, Anders; Saetre, Peter; Nordén, Sara; Sohlenius, Gustav; Andersson, Eva; Petrone, Johannes; Borgiel, Micke; Kautsky, Ulrik; Laudon, Hjalmar

    2016-09-01

    Global warming is expected to be most pronounced in the Arctic where permafrost thaw and release of old carbon may provide an important feedback mechanism to the climate system. To better understand and predict climate effects and feedbacks on the cycling of elements within and between ecosystems in northern latitude landscapes, a thorough understanding of the processes related to transport and cycling of elements is required. A fundamental requirement to reach a better process understanding is to have access to high-quality empirical data on chemical concentrations and biotic properties for a wide range of ecosystem domains and functional units (abiotic and biotic pools). The aim of this study is therefore to make one of the most extensive field data sets from a periglacial catchment readily available that can be used both to describe present-day periglacial processes and to improve predictions of the future. Here we present the sampling and analytical methods, field and laboratory equipment and the resulting biogeochemical data from a state-of-the-art whole-ecosystem investigation of the terrestrial and aquatic parts of a lake catchment in the Kangerlussuaq region, West Greenland. This data set allows for the calculation of whole-ecosystem mass balance budgets for a long list of elements, including carbon, nutrients and major and trace metals. The data set is freely available and can be downloaded from PANGAEA: doi:10.1594/PANGAEA.860961.

  18. A new Eimeria species (Protozoa: Eimeriidae) from caribou in Ameralik, West Greenland.

    Science.gov (United States)

    Skirnisson, K; Cuyler, C

    2016-04-01

    Fecal samples of 11 calves shot in the Ameralik area, West Greenland, in August-September 2014 were examined for coccidian parasites. The calves belonged to a population of interbreeding indigenous caribou Rangifer tarandus groenlandicus and feral semi-domestic Norwegian reindeer Rangifer tarandus tarandus. Two coccidian species were found: Eimeria rangiferis and a coccidium that was identified and described as a new species. The latter's sporulated oocyst is spherical or slightly subspherical. Average size is 25.6 × 24.8 μm. The oocyst has two distinct walls. Wall thickness is ∼1.4 μm. The unicolored outer wall is brown, the inner wall is dark gray. The oocysts contain a small polar granule but are devoid of a microphyle. The oocysts enclose four ovoid-shaped sporocysts with a rounded end opposite to the Stieda body. The average size of sporocysts is 15.2 × 7.8 μm. Sporocysts contain a granular sporocyst residuum that forms a spherical cluster between the sporocysts, one large refractile body is present in each sporozoite. The spherical form easily distinguishes oocysts of the new species from the seven previously described eimerid species in R. tarandus. This is the first eimerid described as a new species to the sciences from caribou in the Nearctic.

  19. Mesozooplankton size data from the fjord branch Kapisigdlit located in the Godthaabsfjord system, West Greenland

    DEFF Research Database (Denmark)

    2013-01-01

    branch, in the middle of a shallower inner creek . St. 1-4 was covering deeper parts of the fjord, and St. 5 was located on the slope leading up to the shallow inner creek. Mesozooplankton was sampled by vertical net tows using a Hydrobios Multinet (type Mini) equipped with a flow meter and 50 µm mesh......Sampling was conducted from March 24 to August 5 2010, in the fjord branch Kapisigdlit located in the inner part of the Godthåbsfjord system, West Greenland. The vessel "Lille Masik" was used during all cruises except on June 17-18 where sampling was done from RV Dana (National Institute...... for Aquatic Resources, Denmark). A total of 15 cruises (of 1-2 days duration) 7-10 days apart was carried out along a transect composed of 6 stations (St.), spanning the length of the 26 km long fjord branch. St. 1 was located at the mouth of the fjord branch and St. 6 was located at the end of the fjord...

  20. Mesozooplankton abundance data from the fjord branch Kapisigdlit located in the Godthaabsfjord system, West Greenland, 2010

    DEFF Research Database (Denmark)

    2013-01-01

    branch, in the middle of a shallower inner creek . St. 1-4 was covering deeper parts of the fjord, and St. 5 was located on the slope leading up to the shallow inner creek. Mesozooplankton was sampled by vertical net tows using a Hydrobios Multinet (type Mini) equipped with a flow meter and 50 µm mesh......Sampling was conducted from March 24 to August 5 2010, in the fjord branch Kapisigdlit located in the inner part of the Godthåbsfjord system, West Greenland. The vessel "Lille Masik" was used during all cruises except on June 17-18 where sampling was done from RV Dana (National Institute...... for Aquatic Resources, Denmark). A total of 15 cruises (of 1-2 days duration) 7-10 days apart was carried out along a transect composed of 6 stations (St.), spanning the length of the 26 km long fjord branch. St. 1 was located at the mouth of the fjord branch and St. 6 was located at the end of the fjord...

  1. Three recent ice entrapments of Arctic cetaceans in West Greenland and the eastern Canadian High Arctic

    Directory of Open Access Journals (Sweden)

    MP Heide-Jørgensen

    2002-07-01

    Full Text Available Three ice entrapments of Monodontids have been reported in the western North Atlantic since 1993. Hunters in Disko Bay, West Greenland, discovered one in March 1994 that included about 150 narwhals (Monodon monoceros. The entrapment occurred during a sudden cold period which caused ice to form rapidly. The trapped whales were subject to hunting, but about 50 of the killed whales could not be retrieved in the ice. The whales were trapped in a small opening in the ice and because of that they would probably have succumbed even if not discovered by hunters. Two entrapments involving white whales or belugas (Delphinapterus leucas occurred in the eastern Canadian Arctic in May 1999; one in Lancaster Sound discovered by polar bear (Ursus maritimus researchers and one in Jones Sound discovered by hunters. The first included one bowhead whale (Balaena mysticetus and about 40 belugas that were being preyed upon by polar bears. The second involved at least 170 belugas, of which about 100 were killed by polar bears and 17 were taken by hunters. The entrapments in Disko Bay and Jones Sound both occurred in areas where entrapments have previously been reported, whereas the one in Lancaster Sound was in a new area.

  2. Eimeria rangiferis (Protozoa: Eimeriidae reported from caribou in Ameralik, West Greenland

    Directory of Open Access Journals (Sweden)

    Karl Skírnisson

    2015-03-01

    Full Text Available In recent decades the native Barren-ground caribou (Rangifer tarandus groenlandicus south of the Godthaabs fjord (Nuup Kangerlua fjord in West Greenland have mixed with semi-domesticated Norwegian reindeer (R. t. tarandus imported in 1952 from Finnmark Norway and released onto the range of the Ameralik caribou population. Fecal samples from three calves of the Ameralik caribou population were examined for the presence of nematode eggs and eimerid oocysts. Two distinct nematode egg types were observed: the first, Nematodirella longissimespiculata, was found in all calves, while the second, a strongylid nematode, was detected in one calf. The coccidian eimerid Eimeria rangiferis was identified in all calves. This host-specific eimerid is found in Icelandic feral reindeer, which were also imported from Finnmark Norway. We suggest that Finnmark reindeer were the source of Eimeria rangiferis observed in Ameralik caribou today. There are three possible origins for the presence of N. longissimespiculata in Ameralik, 1 arrival with colonizing caribou from North America within the past 4000 years, 2 the 1952 introduction of semi-domesticated Norwegian reindeer, or 3 the current immigration of muskoxen.

  3. Investigating the potential for "water piracy" in North East Greenland

    Science.gov (United States)

    Karlsson, Nanna B.; Dahl-Jensen, Dorthe

    2013-04-01

    The incorporation of subglacial processes in ice flow models remains a challenge while at the same time observational evidence increasingly underscores the important role liquid water plays in ice flow dynamics. One of the many problems ice flow models face (that also includes scarcity of data at the bed and the deformational properties of water-saturated sediments) is the different time-scales on which the processes operate. For example, observations indicate that subglacial water may be re-routed to a neighbouring ice stream in response to changes in surface elevation. This implies that ice flow models have to allow for changes in ice flow mode where, depending on the basal properties, the flow may be dominated by deformation or basal sliding. The re-routing of water between neighbouring ice streams is often termed "water piracy" and in this study we demonstrate that the potential for water piracy exists even in regions with very small surface elevation changes. We use a simple, vertically integrated, 2D-plane ice flow model based on the shallow ice flow approximation to model the large-scale changes in surface elevation of North East Greenland in response to gravity and mass balance. Considering time-scales of 100-500 years the model predicts changes in elevation of less than a metre per year which is in agreement with data from remote sensing. We then calculate the corresponding changes in hydrological pressure potential and use evidence from radio-echo sounding data to identify areas with basal melting and thus potential liquid water production. The corresponding change in hydrological pressure potential in response to the surface elevation changes is sufficient to divert the subglacial water to different pathways. This change in subglacial water pathways could be sufficient to change the ice flow mode from deformation to sliding and might initiate speed-up and/or slow-down of the ice streams at the margins of the basin.

  4. Investigations of Liquid Water Retention in the Greenland Firn Aquifer

    Science.gov (United States)

    Forster, R. R.; Miège, C.; Solomon, D. K.; Koenig, L.; Miller, O. L.; Schmerr, N. C.; Montgomery, L. N.

    2015-12-01

    Liquid water is retained year-round within the Greenland firn aquifer in the subsurface pore space predominantly in the southeast region of the ice sheet where accumulation and melt rates are high. Our group uses a combination of remote sensing methods and field-based measurements to investigate the aquifer near Helheim Glacier. We map the current spatial extent of the aquifer system from airborne radar measurements on board NASA's Operation IceBridge (OIB) developed at the University of Kansas's Center for Remote Sensing of the Ice Sheets (CReSIS). Ground-based measurements from five field campaigns (2011, 2013, 2014, and two in 2015) are used to investigate the depth, thickness, and volume of water, hydraulic properties of the aquifer system, water saturation concentrations, residence time of the water, and the flow within the aquifer. Techniques include ground penetrating radar, seismic refraction, nuclear magnetic resonance sounding, pumping tests, and environmental tracer measurements. We also model the potential of aquifer discharge into a crevasse to initiate a fracture to the bed of the ice sheet. These types of investigations are needed to understand the aquifers influence on the ice sheet's mass balance.

  5. Tidewater Dynamics at Store Glacier, West Greenland from Daily Repeat UAV Survey

    Science.gov (United States)

    Hubbard, A., II; Ryan, J.; Toberg, N.; Todd, J.; Christoffersen, P.; Snooke, N.; Box, J. E.

    2015-12-01

    A significant component of the Greenland ice sheet's mass wasteage to sea level rise is attributed to the acceleration and dynamic thinning at its tidewater margins. To improve understanding of the rapid mass loss processes occurring at large tidewater glaciers, we conducted a suite of daily repeat aerial surveys across the terminus of Store Glacier, a large outlet draining the western Greenland Ice Sheet, from May to July 2014 (https://www.youtube.com/watch?v=-y8kauAVAfE). A suite flock of Unmanned Aerial Vehicles (UAVs) were equipped with digital cameras, which, in combination with onboard GPS, enabled production of high spatial resolution orthophotos and digital elevation models (DEMs) using standard structure-from-motion techniques. These data provide insight into the short-term dynamics of Store Glacier surrounding the break-up of the sea-ice mélange that occurred between 4 and 7 June. Feature tracking of the orthophotos reveals that mean speed of the terminus is 16 - 18 md-1, which was independently verified against a high temporal resolution time-series derived from an expendable/telemetric GPS deployed at the terminus. Differencing the surface area of successive orthophotos enable quantification of daily calving rates, which significantly increase just after melange break-up. Likewise, by differencing bulk freeboard volume of icebergs through time we could also constrain the magnitude and variation of submarine melt. We calculate a mean submarine melt rate of 0.18 md-1 throughout the spring period with relatively little supraglacial runoff and no active meltwater plumes to stimulate fjord circulation and upwelling of deeper, warmer water masses. Finally, we relate calving rates to the zonation and depth of water-filled crevasses, which were prominent across parts of the terminus from June onwards.

  6. Tidewater dynamics at Store Glacier, West Greenland from daily repeat UAV surveys

    Science.gov (United States)

    Ryan, Jonathan; Hubbard, Alun; Toberg, Nick; Box, Jason; Todd, Joe; Christoffersen, Poul; Neal, Snooke

    2017-04-01

    A significant component of the Greenland ice sheet's mass wasteage to sea level rise is attributed to the acceleration and dynamic thinning at its tidewater margins. To improve understanding of the rapid mass loss processes occurring at large tidewater glaciers, we conducted a suite of daily repeat aerial surveys across the terminus of Store Glacier, a large outlet draining the western Greenland Ice Sheet, from May to July 2014 (https://www.youtube.com/watch?v=-y8kauAVAfE). The unmanned aerial vehicles (UAVs) were equipped with digital cameras, which, in combination with onboard GPS, enabled production of high spatial resolution orthophotos and digital elevation models (DEMs) using standard structure-from-motion techniques. These data provide insight into the short-term dynamics of Store Glacier surrounding the break-up of the sea-ice mélange that occurred between 4 and 7 June. Feature tracking of the orthophotos reveals that mean speed of the terminus is 16 - 18 m per day, which was independently verified against a high temporal resolution time-series derived from an expendable/telemetric GPS deployed at the terminus. Differencing the surface area of successive orthophotos enable quantification of daily calving rates, which significantly increase just after melange break-up. Likewise, by differencing bulk freeboard volume of icebergs through time we could also constrain the magnitude and variation of submarine melt. We calculate a mean submarine melt rate of 0.18 m per day throughout the spring period with relatively little supraglacial runoff and no active meltwater plumes to stimulate fjord circulation and upwelling of deeper, warmer water masses. Finally, we relate calving rates to the zonation and depth of water-filled crevasses, which were prominent across parts of the terminus from June onwards.

  7. A checklist of the fish fauna of Greenland waters

    DEFF Research Database (Denmark)

    Møller, Peter R.; Nielsen, Jørgen G.; Knudsen, Steen W.

    2010-01-01

    Although the Greenland fish fauna has been studied for more than 200 years, new species continue to be discovered. We here take the opportunity of the International Polar Year 2007-08 (IPY) to present an updated check-list of the fishes of Greenland and discuss whether the growing diversity can...

  8. Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland

    Science.gov (United States)

    Hogan, Kelly A.; Ó Cofaigh, Colm; Jennings, Anne E.; Dowdeswell, Julian A.; Hiemstra, John F.

    2016-09-01

    Recent work has confirmed that grounded ice reached the shelf break in central West Greenland during the Last Glacial Maximum (LGM). Here we use a combination of marine sediment-core data, including glacimarine lithofacies and IRD proxy records, and geomorphological and acoustic facies evidence to examine the nature of and controls on the retreat of a major outlet of the western sector of the Greenland Ice Sheet (GrIS) across the shelf. Retreat of this outlet, which contained the ancestral Jakobshavns Isbræ ice stream, from the outer shelf in Disko Trough was rapid and progressed predominantly through iceberg calving, however, minor pauses in retreat (tens of years) occurred on the middle shelf at a trough narrowing forming subtle grounding-zone wedges. By 12.1 cal kyr BP ice had retreated to a basalt escarpment and shallow banks on the inner continental shelf, where it was pinned and stabilised for at least 100 years. During this time the ice margin appears to have formed a calving bay over the trough and melting became an important mechanism of ice-mass loss. Fine-grained sediments (muds) were deposited alternately with IRD-rich sediments (diamictons) forming a characteristic deglacial lithofacies that may be related to seasonal climatic cycles. High influxes of subglacial meltwater, emanating from the nearby ice margins, deposited muddy sediments during the warmer summer months whereas winters were dominated by iceberg calving leading to the deposition of the diamictons. This is the first example of this glacimarine lithofacies from a continental-shelf setting and we suggest that the calving-bay configuration of the ice margin, plus the switching between calving and melting as ablation mechanisms, facilitated its deposition by channelling meltwater and icebergs through the inner trough. The occurrence of a major stillstand on the inner shelf in Disko Trough demonstrates that the ice-dynamical response to local topography was a crucial control on the behaviour

  9. Meltwater flux and runoff modeling in the abalation area of jakobshavn Isbrae, West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Mernild, Sebastian Haugard [Los Alamos National Laboratory; Chylek, Petr [Los Alamos National Laboratory; Liston, Glen [COLORADO STATE UNIV.; Steffen, Konrad [UNIV OF COLORADO

    2009-01-01

    The temporal variability in surface snow and glacier melt flux and runoff were investigated for the ablation area of lakobshavn Isbrae, West Greenland. High-resolution meteorological observations both on and outside the Greenland Ice Sheet (GrIS) were used as model input. Realistic descriptions of snow accumulation, snow and glacier-ice melt, and runoff are essential to understand trends in ice sheet surface properties and processes. SnowModel, a physically based, spatially distributed meteorological and snow-evolution modeling system was used to simulate the temporal variability of lakobshavn Isbrre accumulation and ablation processes for 2000/01-2006/07. Winter snow-depth observations and MODIS satellite-derived summer melt observations were used for model validation of accumulation and ablation. Simulations agreed well with observed values. Simulated annual surface melt varied from as low as 3.83 x 10{sup 9} m{sup 3} (2001/02) to as high as 8.64 x 10{sup 9} m{sup 3} (2004/05). Modeled surface melt occurred at elevations reaching 1,870 m a.s.l. for 2004/05, while the equilibrium line altitude (ELA) fluctuated from 990 to 1,210 m a.s.l. during the simulation period. The SnowModel meltwater retention and refreezing routines considerably reduce the amount of meltwater available as ice sheet runoff; without these routines the lakobshavn surface runoff would be overestimated by an average of 80%. From September/October through May/June no runoff events were simulated. The modeled interannual runoff variability varied from 1.81 x 10{sup 9} m{sup 3} (2001/02) to 5.21 x 10{sup 9} m{sup 3} (2004/05), yielding a cumulative runoff at the Jakobshavn glacier terminus of {approx}2.25 m w.eq. to {approx}4.5 m w.eq., respectively. The average modeled lakobshavn runoff of {approx}3.4 km{sup 3} y{sup -1} was merged with previous estimates of Jakobshavn ice discharge to quantify the freshwater flux to Illulissat Icefiord. For both runoff and ice discharge the average trends are

  10. Greenlandic water and sanitation-a context oriented analysis of system challenges towards local sustainable development.

    Science.gov (United States)

    Hendriksen, Kåre; Hoffmann, Birgitte

    2017-08-28

    Today, as Greenland focuses on more economic and cultural autonomy, the continued development of societal infrastructure systems is vital. At the same time, pressure is put on the systems by a lack of financial resources and locally based professional competences as well as new market-based forms of organization. Against this background, the article discusses the challenges facing Greenland's self-rule in relation to further develop the existing water and wastewater systems so that they can contribute to the sustainable development of Greenland. The article reviews the historical development of the water supply and wastewater system. This leads to an analysis of the sectorisation, which in recent decades has reorganized the Greenlandic infrastructures, and of how this process is influencing local sustainable development. The article discusses the socio-economic and human impacts and points to the need for developing the water and sanitation system to support not only hygiene and health, but also local sustainable development.

  11. Estimating ice-melange properties with repeat UAV surveys over Store Glacier, West Greenland

    Science.gov (United States)

    Toberg, Nick; Ryan, Johnny; Christoffersen, Poul; Snooke, Neal; Todd, Joe; Hubbard, Alun

    2016-04-01

    In the past decade, tidewater outlet glaciers of the Greenland ice sheet (GrIS) have thinned and retreated when compared to the 1980s when the ice sheet was in a state of dynamic balance. With a growing amount of ice discharged into the sea by tidewater glaciers as well as more ice melting on the surface, the Greenland Ice Sheet has become the single largest cryospheric source of global sea level rise. Today, the ice sheet causes sea level rise of 1 mm per year, highlighting the need to understand the ice sheet's response to climate change. Atmospheric warming will inevitably continue to increase surface meltwater production, but the dynamic response, which includes hundreds of fast-flowing tidewater glaciers, is largely unknown. To develop new understanding of ice sheet dynamics, we investigated the mechanism whereby icebergs break off tidewater glaciers and form a proglacial ice melange. This melange is rigid in winter when sea ice and friction along the sidewalls of the fjord, or even at the sea floor, hold it together. The result is a resistive force, which reduces the rate of iceberg calving when the ice melange is rigid and is lost when the melange disappears in the summer. From early May to late July 2014, we launched unmanned aerial vehicles (UAVs) from a basecamp on a bluff overlooking the calving front of Store Glacier, a 5 km wide tidewater glacier flowing into Uummannaq Fjord in West Greenland. The Skywalker X8 UAVs had a wing-span of 2.1m and a payload containing a high resolution camera, an autopilot system and a GPS data logger. We generated almost 70,000 georeferenced images during 63 sorties over the glacier during a 10 week field season starting 13 May 2014. The images were used to construct orhorectified mosaics and digital elevation models of the proglacial melange with Photoscan structure-from-motion software. The imagery and the DEMs were analysed statistically to understand the spatial characteristics of the ice melange. By combining the

  12. 西格陵兰附近海域表层沉积硅藻组合%DIATOM ASSEMBLAGES FROM SURFACE SEDIMENTS, WEST OF GREENLAND

    Institute of Scientific and Technical Information of China (English)

    何晋娜; 沙龙滨; 刘焱光; 蒋辉

    2011-01-01

    Correspondence analysis was made for the diatom data from surface sediments in the west of Greenland. A total of 35 samples were divided into five assemblages based on the scores of samples, and the results show that the diatom assemblages are dominated by sea-ice species, Arctic species and cold-water species in the study area, whereas warm-water species mainly exist in the Labrador Sea. Moreover, the environmental variables (e. G. Currents,polar waters,melt-water) of the west of Greenland were also discussed in this paper. It is proved that there is a good correlation between the diatom surface sediment assemblages and the environmental variables mentioned above.%通过对西格陵兰附近海域表层沉积硅藻进行研究,并运用对应分析方法对硅藻种属及站点进行分析处理,研究结果表明,海冰种和极地种为该海域的优势种,而暖水种主要分布在拉布拉多海.根据对应分析站点的得分情况,将35个站点划分为5个硅藻组合,并对每个组合分布区域的环境影响因子,如:洋流、极地水团、陆地冰川融水等进行了分析,结果证明西格陵兰附近海域表层沉积硅藻的分布与上述环境因子密切相关.

  13. Observations of runoff and sediment and dissolved loads from the Greenland Ice Sheet at Kangerlussuaq, West Greenland, 2007 to 2010

    DEFF Research Database (Denmark)

    Hasholt, Bent; Mikkelsen, Andreas Peter Bech; Nielsen, Morten Holtegaard

    2012-01-01

    Observations from 2007 to 2010 of runoff, sediment and solute delivery from a segment of the Greenland Ice Sheet (GrIS) and the proglacial landscape draining into the fjord at Kangerlussuaq are presented. The observations include at least three jökulhlaups and extreme recordings from 2010...... previously published for 2007 and 2008. The average effective erosion from the catchment was 0.28 mm (min. 0.18 and max. 0.45 mm). The erosion is larger than indicated from most other locations along the GrIS, but in the same order of magnitude as erosion in other glaciated areas at the same latitude, e.......g. Norway. The sandur in the proglacial area acts as a sediment sink for a lot of the sediments from the GrIS....

  14. Annual down-glacier drainage of lakes and water-filled crevasses at Helheim Glacier, southeast Greenland

    Science.gov (United States)

    Everett, A.; Murray, T.; Selmes, N.; Rutt, I. C.; Luckman, A.; James, T. D.; Clason, C.; O'Leary, M.; Karunarathna, H.; Moloney, V.; Reeve, D. E.

    2016-10-01

    Supraglacial lake drainage events are common on the Greenland ice sheet. Observations on the west coast typically show an up-glacier progression of drainage as the annual melt extent spreads inland. We use a suite of remote sensing and modeling techniques in order to study a series of lakes and water-filled crevasses within 20 km of the terminus of Helheim Glacier, southeast Greenland. Automatic classification of surface water areas shows a down-glacier progression of drainage, which occurs in the majority of years between 2007 and 2014. We demonstrate that a linear elastic fracture mechanics model can reliably predict the drainage of the uppermost supraglacial lake in the system but cannot explain the pattern of filling and draining observed in areas of surface water downstream. We propose that the water levels in crevasses downstream of the supraglacial lake can be explained by a transient high-pressure wave passing through the subglacial system following the lake drainage. We support this hypothesis with analysis of the subglacial hydrological conditions, which can explain both the position and interannual variation in filling order of these crevasses. Similar behavior has been observed in association with jökulhaups, surging glaciers, and Antarctic subglacial lakes but has not previously been observed on major outlets of the Greenland ice sheet. Our results suggest that the behavior of near-terminus surface water may differ considerably from that of inland supraglacial lakes, with the potential for basal water pressures to influence the presence of surface water in crevasses close to the terminus of tidewater glaciers.

  15. The pre-LGM evolution of the Uummannaq ice Stream system in West Greenland

    Science.gov (United States)

    Roberts, David; Lane, Tim; Rea, Brice; Jamieson, Stewart

    2016-04-01

    Ice streams are a key component of an ice sheet system. They are fast flowing, dynamic corridors of ice that play a pivotal role in modulating ice flux from the interior of an ice sheet to its terrestrial or marine margin. The behaviour of marine-terminating ice streams in particular is critical in determining the dynamic (in)stability of ice sheets and ice/ocean interaction through time. However, despite an increase in palaeo-ice stream reconstructions and improvements in numerical modelling, in many instances we know little about the evolution of ice streams beyond the last glacial cycle. This is particularly true for topographically-guided or constrained ice stream systems that must represent the end-member state of a system that has developed over million year time scales. Recent research suggests that topographic focussing, subglacial geology, meltwater routing and calving margins are the primary controls on ice stream evolution. However, few studies have considered the combined role of geology, pre Quaternary landscapes and uplift in pre-conditioning a landscape for ice stream onset. This paper explores the factors that have controlled the evolution of the Uummannaq Ice Stream (UIS) system in West Greenland. During the last glacial cycle the UIS was a topographically-guided system, but the variables that led to ice stream onset prior to the Late Quaternary remain poorly understood. Geology, selective linear erosion and dynamic feedbacks were all important controls, but the influence of rifting, early uplift and pre-glacial topography in particular may have been pivotal controls on the evolution and location of the UIS onset zone.

  16. Are warbles and bots related to reproductive status in West Greenland caribou?

    Directory of Open Access Journals (Sweden)

    Christine Cuyler

    2012-03-01

    Full Text Available In March-April 2008-09, using CARMA protocols, 81 cows and 16 calves were collected in West Greenland from two caribou populations; Akia-Maniitsoq (AM and Kangerlussuaq-Sisimiut (KS. In both populations, warble larvae numbers were highest in calves and higher in non-pregnant than pregnant cows. Nose bots showed no relationship with pregnancy or lactation; KS calves had higher nose bot loads than cows, a pattern not observed in AM. Pregnant cows had more rump fat than non-pregnant cows. KS cows lacking rump fat entirely had the highest warble burdens. We observed lactating pregnant cows with moderate larval burdens. Projected energy cost of the heaviest observed combined larvae burdens was equivalent to 2-5 days basal metabolic rate (BMR for a cow, and 7-12 days BMR for a calf. Foregone fattening in adult cows with average burdens was 0.2 to 0.5 kg, but almost doubled with the heaviest infestations to 0.4 and 0.8 kg. Average burdens in calves resulted in forgone fattening of about 0.5 kg, with peak costs equivalent to 0.7 and 1.1 kg fat for AM and KS calves respectively. Although modest, these projected energy costs of hosting larvae for cows support the negative relationship between rump fat and larvae burden. For calves, hosting high burdens of warble larvae could affect winter survival, specifically those weaned normally in October or in early winter. Harmful effects of oestrid larvae burdens may remain subtle but clearly cumulative in relation to seasonal forage availability and incidence of other parasites.

  17. Greenlandic water and sanitation-a context oriented analysis of system challenges towards local sustainable development

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Hoffmann, Birgitte

    2017-01-01

    Today, as Greenland focuses on more economic and cultural autonomy, the continued development of societal infrastructure systems is vital. At the same time, pressure is put on the systems by a lack of financial resources and locally based professional competences as well as new market-based forms...... of organization. Against this background, the article discusses the challenges facing Greenland's self-rule in relation to further develop the existing water and wastewater systems so that they can contribute to the sustainable development of Greenland. The article reviews the historical development of the water...... supply and wastewater system. This leads to an analysis of the sectorisation, which in recent decades has reorganized the Greenlandic infrastructures, and of how this process is influencing local sustainable development. The article discusses the socio-economic and human impacts and points to the need...

  18. Local and synoptic controls on rapid supraglacial lake drainage in West Greenland

    Science.gov (United States)

    Williamson, Andrew; Banwell, Alison; Arnold, Neil; Willis, Ian

    2016-04-01

    Many supraglacial lakes within the ablation zone of the Greenland Ice Sheet (GrIS) are known to drain rapidly (in scale factors, such as ice thickness, driving stresses, ice velocities and strain rates. A combination of the local water-volume threshold and one or more synoptic-scale factors may explain the overall patterns of rapid lake drainage, but this requires verification using targeted field- and remotely-based studies that cover large areas of the GrIS and span long timescales. Here, we investigate a range of potential controls on rapid supraglacial lake drainage in the land-terminating Paakitsoq region of the ice sheet, northeast of Jakobshavn Isbræ, for the 2014 melt season. We have analysed daily 250-m Moderate Resolution Imaging Spectroradiometer (MODIS) imagery in order to calculate lake areas, depths and volumes, and have developed an automatic lake-tracking algorithm to determine the dates on which all rapid lake drainage events occur. For each rapidly draining lake, the water volumes immediately prior to drainage are compared with other local factors, notably lake-filling rate and ice thickness, and with a variety of synoptic-scale features, such as slope angles, driving stresses, surface velocities, surface strain rates and the incidence of nearby lake-drainage events. We present the outcomes of our statistical analysis to elicit the statistically significant controls on hydrofracture beneath supraglacial lakes.

  19. Ice-ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

    Science.gov (United States)

    Chauché, N.; Hubbard, A.; Gascard, J.-C.; Box, J. E.; Bates, R.; Koppes, M.; Sole, A.; Christoffersen, P.; Patton, H.

    2014-08-01

    Warm, subtropical-originating Atlantic water (AW) has been identified as a primary driver of mass loss across the marine sectors of the Greenland Ice Sheet (GrIS), yet the specific processes by which this water mass interacts with and erodes the calving front of tidewater glaciers is frequently modelled and much speculated upon but remains largely unobserved. We present a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estimation from Rink and Store glaciers, two major marine outlets draining the western sector of the GrIS during 2009 and 2010. We characterise the main water bodies present and interpret their interaction with their respective calving fronts. We identify two distinct processes of ice-ocean interaction which have distinct spatial and temporal footprints: (1) homogenous free convective melting which occurs across the calving front where AW is in direct contact with the ice mass, and (2) localised upwelling-driven melt by turbulent subglacial runoff mixing with fjord water which occurs at distinct injection points across the calving front. Throughout the study, AW at 2.8 ± 0.2 °C was consistently observed in contact with both glaciers below 450 m depth, yielding homogenous, free convective submarine melting up to ~200 m depth. Above this bottom layer, multiple interactions are identified, primarily controlled by the rate of subglacial fresh-water discharge which results in localised and discrete upwelling plumes. In the record melt year of 2010, the Store Glacier calving face was dominated by these runoff-driven plumes which led to a highly crenulated frontal geometry characterised by large embayments at the subglacial portals separated by headlands which are dominated by calving. Rink Glacier, which is significantly deeper than Store has a larger proportion of its submerged calving face exposed to AW, which results in a uniform, relatively flat overall frontal geometry.

  20. Fatty Acid Composition of Muscle, Adipose Tissue and Liver from Muskoxen (Ovibos moschatus) Living in West Greenland.

    Science.gov (United States)

    Alves, Susana P; Raundrup, Katrine; Cabo, Ângelo; Bessa, Rui J B; Almeida, André M

    2015-01-01

    Information about lipid content and fatty acid (FA) composition of muskoxen (Ovibos moschatos) edible tissues is very limited in comparison to other meat sources. Thus, this work aims to present the first in-depth characterization of the FA profile of meat, subcutaneous adipose tissue and liver of muskoxen living in West Greenland. Furthermore, we aim to evaluate the effect of sex in the FA composition of these edible tissues. Samples from muscle (Longissimus dorsi), subcutaneous adipose tissue and liver were collected from female and male muskoxen, which were delivered at the butchery in Kangerlussuaq (West Greenland) during the winter hunting season. The lipid content of muscle, adipose tissue and liver averaged 284, 846 and 173 mg/g of dry tissue, respectively. This large lipid contents confirms that in late winter, when forage availability is scarce, muskoxen from West Greenland still have high fat reserves, demonstrating that they are well adapted to seasonal feed restriction. A detailed characterization of FA and dimethylacetal composition of muskoxen muscle, subcutaneous adipose tissue and liver showed that there are little differences on FA composition between sexes. Nevertheless, the 18:1cis-9 was the most abundant FA in muscle and adipose tissue, reaching 43% of total FA in muscle. The high content of 18:1cis-9 suggests that it can be selectively stored in muskoxen tissues. Regarding the nutritional composition of muskoxen edible tissues, they are not a good source of polyunsaturated FA; however, they may contribute to a higher fat intake. Information about the FA composition of muskoxen meat and liver is scarce, so this work can contribute to the characterization of the nutritional fat properties of muskoxen edible tissues and can be also useful to update food composition databases.

  1. Age and sex distributions in the catches of belugas, Delphinapterus leucas , in West Greenland and in western Russia

    DEFF Research Database (Denmark)

    Heide-Jørgensen, M.P.; Lockyer, C.

    2001-01-01

    with mature females were taken. Age was estimated from Growth Layer Groups (GLGs) in sectioned teeth, assuming the currently accepted criteria of 2 GLGs forming annually. The mean and median ages were increasing slightly in both sexes from Upernavik from 1985 through 1994. Both immature and mature whales were...... taken on the wintering grounds from Disko Bay and south. Estimation of survival was confounded by the large number of whales where only a minimum age could be assigned because of tooth wear at the crown (i. e. no neonatal Line in the dentine). The apparent survival rates for belugas from West Greenland...

  2. Gravity changes in mid-west Greenland from GOCE gravity model and gradient data using ground and airborne gravity

    DEFF Research Database (Denmark)

    Tscherning, Carl Christian; Herceg, Matija; Fredenslund Levinsen, Joanna

    GOCE TRF (terrestrial reference frame) vertical anomalous gradients (Tzz) from two periods have been used to determine gravity anomalies changes in mid-west Greenland, where a large mass-loss has been detected using GRACE (Fig. 1). As additional data were used the GOCE DIR-3 model and ground...... gravity at the coast on solid rock, where no mass loss is expected. The methods of Least-Squares Collocation (LSC) and the Reduced Point Mass (RPM) methods have been used, however only LSC included the ground data....

  3. Gas records from the West Greenland ice margin covering the Last Glacial termination: a horizontal ice core

    DEFF Research Database (Denmark)

    Petrenko, V.; Severinghaus, J.P.; Brook, E.J.

    2006-01-01

    Certain sites along ice sheet margins provide an easily accessible and almost unlimited supply of ancient ice at the surface. Measurements of gases in trapped air from ice outcropping at Pakitsoq, West Greenland, demonstrate that ancient air is mostly well preserved. No alterations in delta O-18......-uniformly thinned, with many cross-cutting bands of bubble-free ice and dust. The cross-cutting features are associated with anomalies in both the gas and the ice records. With careful sampling to avoid these, the ice at Pakitsoq is suitable for recovery of large-volume samples of the ancient atmosphere...

  4. Environmental Oil Spill Sensitivity Atlas for the Northern West Greenland (72°-75° N) Coastal Zone

    DEFF Research Database (Denmark)

    Stjernholm, Michael; Boertmann, David; Mosbech, Anders

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenland between 72º N and 75º N. The coastal zone is divided into 118 shoreline segments and the offshore zone into 3 areas. A sensitivity index value is calculated for each segment/area, and each segment....../area is subsequently ranked according to four degrees of sensitivity. Besides this general ranking a number of smaller areas are especially selected as they are of particular significance, they are especially vulnerable to oil spills and they have a size making oil spill response possible. The shoreline sensitivity...

  5. Environmental Oil Spill Sensitivity Atlas for the West Greenland (68°-72° N) Coastal Zone, 2nd revised edition

    DEFF Research Database (Denmark)

    Clausen, Daniel Spelling; Johansen, Kasper Lambert; Mosbech, Anders

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenland between 68º N and 72º N. The coastal zone is divided into 199 shoreline segments and the offshore zone into 8 areas. A sensitivity index value is calculated for each segment/area, and each segment....../area is subsequently ranked according to four degrees of sensitivity. Besides this general ranking a number of smaller areas are especially selected as they are of particular significance, they are especially vulnerable to oil spills and they have a size making oil spill response possible. The shoreline sensitivity...

  6. Changes in recruitment, growth, and stock size of northern shrimp (Pandalus borealis) at West Greenland: temperature and density-dependent effects at released predation pressure

    DEFF Research Database (Denmark)

    Wieland, Kai

    2005-01-01

    increased in all survey regions since the mid-1990s. Length-at-age was positively correlated with temperature in general, but a trend towards slower growth was observed in areas with the highest stock densities in the most recent years. It is concluded that the moderate increase in temperature above a lower......Stock size of northern shrimp (Pandalus borealis) in West Greenland waters has been fairly stable from the late 1980s to the mid-1990s. Thereafter, survey estimates of biomass increased substantially, and the exploitation rate declined slightly in the most recent years. The present analysis...... was carried out oil a spatially disaggregated basis in order to account for the latitudinal differences in bottom temperature and shrimp density. Changes in recruitment and, with a lag of 2 years, in stock biomass were most pronounced in the northern part of its distributional range, while bottom temperature...

  7. Ocean properties, ice–ocean interactions, and calving front morphology at two major west Greenland glaciers

    Directory of Open Access Journals (Sweden)

    N. Chauché

    2013-11-01

    Full Text Available Warm sub-polar mode water (SPMW has been identified as a primary driver of mass loss of marine terminating glaciers draining the Greenland Ice Sheet (GrIS yet, the specific mechanisms by which SPMW interacts with these tidewater termini remain uncertain. We present oceanographic data from Rink Glacier (RG and Store Glacier (SG fjords, two major marine outlets draining the western sector of the GrIS into Baffin Bay over the contrasting melt-seasons of 2009 and 2010. Submarine melting occurs wherever ice is in direct contact with warmer water and the consistent presence of 2.8 °C SPMW adjacent to both ice fronts below 400 m throughout all surveys indicates that melting is maintained by a combination of molecular diffusion and large scale, weak convection, diffusional (hereafter called ubiquitous melting. At shallower depths (50–200 m, cold, brine-enriched water (BEW formed over winter appears to persist into the summer thereby buffering this melt by thermal insulation. Our surveys reveal four main modes of glacier–ocean interaction, governed by water depth and the rate of glacier runoff water (GRW injected into the fjord. Deeper than 200 m, submarine melt is the only process observed, regardless of the intensity of GRW or the depth of injection. However, between the surface and 200 m depth, three further distinct modes are observed governed by the GRW discharge. When GRW is weak (≲1000 m3 s−1, upward motion of the water adjacent to the glacier front is subdued, weak forced or free convection plus diffusional submarine melting dominates at depth, and seaward outflow of melt water occurs from the glacier toe to the base of the insulating BEW. During medium intensity GRW (∼1500 m3 s−1, mixing with SPMW yields deep mixed runoff water (DMRW, which rises as a buoyant plume and intensifies local submarine melting (enhanced buoyancy-driven melting. In this case, DMRW typically attains hydrostatic equilibrium and flows seaward at an

  8. The liquid water balance of the Greenland ice sheet

    Science.gov (United States)

    Steger, Christian; Reijmer, Carleen; van den Broeke, Michiel

    2017-04-01

    Mass loss from the Greenland Ice Sheet (GrIS) is an increasingly important contributor to global sea level rise. During the last decade, the mass loss was dominated by meltwater runoff. Linking actual runoff from the ice sheet to melt and other forms of liquid water input at the surface (rainfall and condensation) is however complex, as liquid water may be retained within the ice sheet due to refreezing and/or (perennial) storage. In the ablation zone on bare ice, liquid water runs of laterally at the surface, accumulates in supraglacial lakes or enters the ice sheet's en- or subglacial hydraulic system via moulins and crevasses. In the higher elevated accumulation zone, liquid water percolates into the porous firn layer and part of it may be retained due to refreezing and/or perennial storage in so called firn aquifers. In this study, we investigate the liquid water balance of the GrIS focussing on the role of the firn layer. For this purpose, we ran SNOWPACK, a relatively complex one-dimensional snow model, on a horizontal resolution of ˜ 11km and for the transient period of 1960 to 2015. At the snow-atmosphere-interface, the model was forced by output of the regional atmospheric climate model RACMO2.3. A comparison of SNOWPACK with in-situ observations (firn density profiles) and remote sensing data (firn aquifer locations inferred from radar measurements) indicated a good agreement for most climatic conditions. On a GrIS-wide scale, the modelled surface mass balance of SNOWPACK exhibits, in combination with ice-discharge data for ocean-terminating glaciers, an excellent agreement with GRACE data for the period 2003 - 2012. GrIS-integrated amounts of surface melt reveal a significant positive trend (+11.6Gta-2) in the second half of the simulation period. Within this interval, the trend in runoff is larger (+8.3Gta-2) than the one in refreezing (+3.6Gta-2), which results in an overall decrease of the refreezing fraction. This decrease is for instance less

  9. Estimating supraglacial lake depth in West Greenland using Landsat 8 and comparison with other multispectral methods

    Science.gov (United States)

    Pope, A.; Scambos, T. A.; Moussavi, M.; Tedesco, M.; Willis, M.; Shean, D.; Grigsby, S.

    2016-01-01

    Liquid water stored on the surface of ice sheets and glaciers impacts surface mass balance, ice dynamics, and heat transport. Multispectral remote sensing can be used to detect supraglacial lakes and estimate their depth and area. In this study, we use in situ spectral and bathymetric data to assess lake depth retrieval using the recently launched Landsat 8 Operational Land Imager (OLI). We also extend our analysis to other multispectral sensors to evaluate their performance with similar methods. Digital elevation models derived from WorldView stereo imagery (pre-lake filling and post-drainage) are used to validate spectrally derived depths, combined with a lake edge determination from imagery. The optimal supraglacial lake depth retrieval is a physically based single-band model applied to two OLI bands independently (red and panchromatic) that are then averaged together. When OLI- and WorldView-derived depths are differenced, they yield a mean and standard deviation of 0.0 ± 1.6 m. This method is then applied to OLI data for the Sermeq Kujalleq (Jakobshavn Isbræ) region of Greenland to study the spatial and intra-seasonal variability of supraglacial lakes during summer 2014. We also give coefficients for estimating supraglacial lake depth using a similar method with other multispectral sensors.

  10. 3D-seismic observations of Late Pleistocene glacial dynamics on the central West Greenland margin

    Science.gov (United States)

    Hofmann, Julia; Knutz, Paul; Cofaigh, Colm Ó.

    2016-04-01

    suggesting the transition between grounded ice and a glacimarine setting. The back-stepping scarps are suggestive of slide scars that were created as a result of mass movement induced by instabilities along the NW slope. The buried section contains morphologies indicating an asymmetric feature with a steeper side facing south. It comprises a thickness of c. 100 m and a length of c. 28 km. The detailed surface observations and seismic geometries suggest that the northern area represents a relict grounding-zone wedge (GZW). The wedge is covered by stratified deposits suggesting that it was at least occasionally submarine after its formation and may have served as pinning-point for floating ice shelves during periods of the Late TMF Stage. Important implications of the study are the intermittent development of floating ice shelves during the course of the Late Stage of TMF development and the presence of shelf-edge terminating grounded Late Weichselian ice outside of the troughs. Hofmann, J.C., Knutz, P.C., Nielsen, T., Kuijpers, A., submitted. Seismic architecture and evolution of the Disko Bay trough-mouth fan, central West Greenland margin. Quaternary Science Reviews.

  11. Diagenesis and reservoir properties of Cretaceous-Lower Tertiary sandstones: the GANT-1 well, western Nuussuaq, central West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Kierkegaard, Thomas

    1998-08-01

    The main purpose of this study is to describe the diagenetic alterations occurring in the Cretaceous to Lower Paleocene sedimentary succession of the GANT-1 well, and to determine the diagenetic and detrital factors which control present porosity and permeability. The GANT-1 well is located on north-western Nuussuaq, central West Greenland. The West Greenland margin is a continental margin subdivided into linked basins where Cretaceous to Lower Tertiary and probably older sediments have been deposited. In the Nuussuaq area these sediments are overlain by a succession of Early Tertiary basaltic volcanic rocks which reaches a combined thickness of around 2-2.5 km. Although the reservoir properties of the sandstone intervals in the GANT-1 and GANE-1 wells are generally relatively poor, it is suggested that moderate to good properties may be found in certain intervals within the Maastrichtian-Paleocene succession. However, the reason for the locally enhanced reservoir properties in GANT-1 was not clarified by this study due to the lack of regional petrographical data. (EG) EFP-96. 41 refs., 3 maps

  12. Variation and Distribution of Sediments in a Mixed Glacifluvial-Aeolian System in West Greenland

    Science.gov (United States)

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

    2007-12-01

    There is a clear association between the distribution of wind-blown sediments and the former extent of ice sheets and glaciers. Glacial erosion processes produce significant quantities of fine sediments that are washed out from beneath glaciers by meltwater. Once deposited and desiccated, aeolian processes may transport them across the landscape resulting in the formation of sand dunes and loess, and adding dust to the atmosphere. This research reports the use of digital imaging and laser sizing to obtain the grain size distribution and textural attributes of sand and dust in Sandflugtdalen, a valley adjacent to the West Greenland ice sheet. An initial assessment of the rates of sand and dust transport, made using semi-isokinetic directional sediment samplers, indicate that the flux of aeolian sediment comprises clays, silts and sand-sized particles. Digital imaging of the surficial sediment deposits provides a rapid means of sampling the large, spatially and temporally variable, proglacial valley. Sediments were initially photographed during June 2007 and then resampled after a 9-week interval. The grain size distribution and surface texture were computed using a calibrated autocorrelation method. It is estimated that individual particles may be resolved down to a size of 0.045 mm. The regions of aeolian entrainment, transport and deposition are directly linked to the development and distribution of sediments on the proglacial floodplain, which varies considerably in terms of surface roughness. On the floodplain close to the ice sheet, aeolian flux is controlled by sediment supply and lag formation and the total surface roughness is determined by the combination of grain-scale roughness and topography. Further down valley, recycling of sediments by aeolian and fluvial activity is significant and wind speed becomes an important controlling factor. Within the dunefields, surface roughness is principally determined by topography and vegetation. Close to the ice sheet

  13. Processes and timescales of melt metasomatism in the continental lower crust of West Greenland

    Science.gov (United States)

    Smit, Matthijs; Waight, Tod; Nielsen, Troels

    2017-04-01

    The lower continental crust is infiltrated by mantle-derived melts that are at extreme chemical disequilibrium with this reservoir. The chemical effect, and the degree and extent of melt infiltration within the lower crust are important parameters to investigating the role of this process in modifying local and regional crustal composition. However, in spite of ground-breaking contributions in this field, the processes of melt metasomatism within the lower crust are not entirely clear. Challenges lie in obtaining primary petrological, geochemical and chronological information from deep crustal rocks that are difficult to sample and are often repeatedly recrystallized and chemically modified. In this study, we investigated mafic granulite xenoliths from the crustal root of the Archean North Atlantic Craton (Sarfartôq location) and the adjoining Paleoproterozoic Nagssugtôqidian Orogen (Sisimiut location), West Greenland. These rocks were chosen because: 1) they are xenolith and hence are unaffected by tectonic overprinting, 2) they show a rich petrological record of melt infiltration formed in the run up to their scavenging by the host aillikite magmas, 3) they represent two locations with similar crustal composition and architecture, but different underlying lithospheric mantle enabling teasing-out of the role of melt-mantle interaction. We used various imaging techniques and in-situ chemical analysis by electron-probe micro-analyzer to characterize the different melt pockets within the samples, their textural relationships, as well as their composition. In addition, we performed thermometry and multi-method speedometry (Fe-in-rutile, majors-in-garnet) to assess the conditions and duration of melt infiltration for melts of different texture and composition. The primary granular assemblage of the xenoliths has been infiltrated by three different types of melts, each of which is found in grain boundaries, melt-corroded cracks, and voids formed by melt

  14. Seismic architecture and evolution of the Disko Bay trough-mouth fan, central West Greenland margin

    Science.gov (United States)

    Hofmann, Julia C.; Knutz, Paul C.; Nielsen, Tove; Kuijpers, Antoon

    2016-09-01

    The present study is the first to document the large-scale glacigenic evolution of a West Greenland trough-mouth fan (TMF) system, i.e. the Disko Bay TMF, from onset of shelf-based glaciation to present. We have constrained the paleo-ice sheet configuration in the Disko Bay region and determine the controlling factors of ice-stream development using 2D- and 3D-seismic reflection data, seabed bathymetry and stratigraphic information from two exploration wells. This has revealed three stages of the Disko Bay TMF development. The early stage, probably of Pliocene-early Pleistocene age, marks the onset of a central depocentre located below the modern mid-shelf and constructed by sediment progradation delivered through at least two erosive pathways related to fast-flowing, grounded ice. At that time, ice-stream routing in the Disko Bay shelf region was strongly controlled by the pre-glacial topography and structural boundaries associated with fracture zones and deep-seated faults. During the middle evolutionary stage, the focus of deposition shifted from the mid-shelf to two elongate areas fringing the outer margin. The marginal depocentres were not only related to glacial processes but also alongslope deposition by contour currents, which may have developed as a consequence of basin subsidence surrounding the Davis Strait High and the Kangerluk Structure. The late stage of TMF development, presumably representing the late Pleistocene to Holocene, is characterized by the marginal depocentres becoming less significant and sediment aggradation occurring over wide parts of the mid-outer shelf, while features of subglacial erosion are generally absent. In contrast to the inferred fast-flowing ice streams of the early-middle evolutionary stages, this points to the existence of a rather thin and "lightly" grounded ice sheet, i.e. at the threshold of floatation. The "lightly" grounded ice sheet scenario, applying to the late Pleistocene interval of the Disko Bay TMF, was

  15. Greenlandic water and sanitation systems-identifying system constellation and challenges

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Hoffmann, Birgitte

    2017-01-01

    A good water supply and wastewater management is essential for a local sustainable community development. This is emphasized in the new global goals of the UN Sustainable Development, where the sixth objective is to: "Ensure availability and sustainable management of water and sanitation for all......" (United Nations 2015). This obviously raises the question of how this can be achieved considering the very different conditions and cultures around the globe. This article presents the Greenlandic context and elucidates the current Greenland water supply system and wastewater management system from...

  16. Seasonal and regional variability in dissolved and particulate iron fluxes via glacial runoff along the West Greenland coast

    Science.gov (United States)

    Choquette, K.; Hagedorn, B.; Sletten, R. S.; Harrold, Z.; Liu, L.; Dieser, M.; Cameron, K. A.; Christner, B. C.; Junge, K.

    2012-12-01

    Subglacial weathering, due to biogeochemical and physical weathering processes, can affect the chemical evolution of subglacial waters and release dissolved and particulate iron via glacial runoff. Iron is a growth limiting nutrient and plays a critical role in the biogeochemical cycles of coastal and marine waters. More recently, dissolved and colloidal iron derived from subglacial sources have been considered an important contributor of Fe fluxes to the ocean; however, their dependency on lithology, grain size, and microbial activity is not well understood. This study characterizes the solute chemistry, in particular iron mineralogy and dissolved iron concentrations, released from beneath the Greenland Ice Sheet (GrIS), from two locations along the West Greenland coast, Thule (76°N, 68°W) and Kangerlussuaq (67°N, 50°W). We hypothesize that the subglacial lithology has a control on Fe fluxes from the GrIS to coastal and marine systems. The underlying bedrock in Thule is the Precambrian Dundas and Narssarssuk sedimentary formations which include sandstone, siltstone, and shale. The bedrock in Kangerlussuaq is dominated by Archean granodioritic gneiss and amphibolite within the Nagssugtoqidian Orogen. Supra and subglacial meltwater samples were collected directly in front of the Ice Sheet over an entire melt season in 2011 (North River, Thule) and 2012 (Akuliarusiarsuup Kuua River, Kangerlussuaq). In situ parameters such as temperature, pH, dissolved oxygen, and electrical conductivity were recorded in order to interpret meltwater chemistry. Dissolved Fe(II) and Fe(III) species were fixed immediately and analyzed within 24 hours after sampling in the field laboratory using a spectrophotometer and 10 cm cell. Total dissolved iron (FeT) of different size fractions (cell ICP MS. Preliminary results demonstrate that subglacial meltwater of North River has average FeT concentrations of 200 nM and 10 nM in the <0.22 and <0.05 μm size fraction, respectively

  17. Paleo-Eskimo kitchen midden preservation in permafrost under future climate conditions at Qajaa, West Greenland

    DEFF Research Database (Denmark)

    Elberling, Bo; Matthiesen, Henning; Jørgensen, Christian Juncher;

    2011-01-01

    Remains from Paleo-Eskimo cultures are well-documented, but complete preservation is rare. Two kitchen middens in Greenland are known to hold extremely well-preserved organic artefacts. Here, we assess the fate of the Qajaa site in Western Greenland under future climate conditions based on site...... characteristics measured in situ and from permafrost cores. Measurements of thermal properties, heat generation, oxygen consumption and CO2 production show that the kitchen midden can be characterized as peat but produces 4–7 times more heat than natural sediment. An analytical model from permafrost research has...

  18. The plankton community on Sukkertop and Fylla Banks off West Greenland during a spring bloom and post-bloom period: Hydrography, phytoplankton and protozooplankton

    DEFF Research Database (Denmark)

    Poulsen, Louise K.; Reuss, N.

    2002-01-01

    The plankton community structure was investigated on Sukkertop and Fylla Banks off West Greenland during the spring bloom in May 2000 and the post-bloom period in June 1999. In May a small change in density, clearly illustrated by the profile of potential energy, was sufficient to support a spring...

  19. The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet

    NARCIS (Netherlands)

    van den Broeke, M.R.; Smeets, C.J.P.P.; van de Wal, R.S.W.

    2011-01-01

    We present the seasonal cycle and interannual variability of the surface energy balance (SEB) in the ablation zone of the west Greenland ice sheet, using seven years (September 2003–August 2010) of hourly observations from three automatic weather stations (AWS). The AWS are situated along the 67◦ N

  20. The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet

    NARCIS (Netherlands)

    van den Broeke, M.R.|info:eu-repo/dai/nl/073765643; Smeets, C.J.P.P.|info:eu-repo/dai/nl/191522236; van de Wal, R.S.W.|info:eu-repo/dai/nl/101899556

    2011-01-01

    We present the seasonal cycle and interannual variability of the surface energy balance (SEB) in the ablation zone of the west Greenland ice sheet, using seven years (September 2003–August 2010) of hourly observations from three automatic weather stations (AWS). The AWS are situated along the 67◦ N

  1. Sediment plumes as a proxy for local ice-sheet runoff in Kangerlussuaq Fjord, West Greenland

    NARCIS (Netherlands)

    McGRATH, D.; Steffen, K.; Overeem, I.; Mernild, S. H.; Hasholt, B.; van den Broeke, M.R.

    2010-01-01

    Meltwater runoff is an important component of the mass balance of the Greenland ice sheet (GrIS) and contributes to eustatic sea-level rise. In situ measurements of river runoff at the ∼325 outlets are nonexistent due to logistical difficulties. We develop a novel methodology using satellite observa

  2. Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland

    NARCIS (Netherlands)

    Charalampidis, C.; van As, D.; Box, J. E.; van den Broeke, M. R.; Colgan, W. T.; Doyle, S. H.; Hubbard, A. L.; MacFerrin, M.; Machguth, H.; Smeets, C. J. P. P.

    2015-01-01

    We present 5 years (2009–2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. – above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly ne

  3. Palaeoecology of Holocene peat deposits from Nordvestø, north-west Greenland

    DEFF Research Database (Denmark)

    Bennike, Ole; Goodsite, Michael Evan; Heinemeier, Jan

    2008-01-01

    Two extensive peat deposits on Nordvestø, between Greenland and Canada, were examined for macroscopic remains of plants and animals. One of the peat deposits accumulated during the period from c. 7,100 to 5,100 cal. years BP. This peat is guanogenic and completely dominated by the coprophilous br...

  4. Drainage of the ice-dammed Lake Tinninilik, West Greenland; implication on bedrock uplift

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Bjørk, Anders Anker;

    Drainage of ice-dammed lakes is regularly observed along the margin of the Greenland Ice Sheet. However, the speed of the drainage events and implications can vary depending on the size of the lakes and the local settings. Here, we assess the drainage pattern of Lake Tinninilik, dammed...

  5. Vegetation phenology gradients along the west and east coasts of Greenland from 2001 to 2015

    DEFF Research Database (Denmark)

    Karami, Mojtaba; Hansen, Birger; Westergaard-Nielsen, Andreas

    2017-01-01

    The objective of this paper is to characterize the spatiotemporal variations of vegetation phenology along latitudinal and altitudinal gradients in Greenland, and to examine local and regional climatic drivers. Time-series from the Moderate Resolution Imaging Spectroradiometer (MODIS) were analyzed...

  6. Sediment plumes as a proxy for local ice-sheet runoff in Kangerlussuaq Fjord, West Greenland

    NARCIS (Netherlands)

    McGRATH, D.; Steffen, K.; Overeem, I.; Mernild, S. H.; Hasholt, B.; van den Broeke, M.R.

    2010-01-01

    Meltwater runoff is an important component of the mass balance of the Greenland ice sheet (GrIS) and contributes to eustatic sea-level rise. In situ measurements of river runoff at the ∼325 outlets are nonexistent due to logistical difficulties. We develop a novel methodology using satellite

  7. West Knox Pond water budget and water quality

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this report is to analyze the water budget and water quality for West Knox Pond for the May through September period of 2002 and 2003. The...

  8. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: The Nordre Strømfjord shear zone and the Arfersiorfik quartz diorite in Arfersiorfik, the Nagssugtoqidian orogen, West Greenland

    Directory of Open Access Journals (Sweden)

    Stensgaard, Bo Møller

    2006-12-01

    Full Text Available The Nordre Strømfjord shear zone in the fjord Arfersiorfik, central West Greenland, consists of alternating panels of supracrustal rocks and orthogneisses which together form a vertical zone up to 7 km wide with sinistral transcurrent, ductile deformation, which occurred under middle amphibolite facies conditions. The pelitic and metavolcanic schists and paragneisses are all highly deformed, while the orthogneisses appear more variably deformed, with increasing deformation evident towards the supracrustal units. The c. 1.92 Ga Arfersiorfik quartz diorite is traceable for a distance of at least 35 km from the Inland Ice towards the west-south-west. Towards its northern contact with an intensely deformed schist unit it shows a similar pattern of increasing strain, which is accompanied by chemical and mineralogical changes. The metasomatic changes associated with the shear zone deformation are superimposed on a wide range of original chemical compositions, which reflect magmatic olivine and/or pyroxene as well as hornblende fractionation trends. The chemistry of the Arfersiorfik quartz diorite suite as a whole is comparable to that of Phanerozoic plutonic and volcanic rocks of calc-alkaline affinity.

  9. Longitudinal Inter-Comparison of Modeled and Measured West Greenland Ice Sheet Meltwater Runoff Losses (2004-2014)

    Science.gov (United States)

    Moustafa, S.; Rennermalm, A. K.; Tedesco, M.; Mote, T. L.; Koenig, L.; Smith, L. C.; Hagedorn, B.; Overeem, I.; Sletten, R. S.; Mikkelsen, A. B.; Hasholt, B.; Hall, D. K.

    2015-12-01

    Increased surface meltwater runoff, that exits the Greenland ice sheet (GrIS) margin via supra-, en-, and sub-glacial drainage networks into fjords, pro-glacial lakes and rivers, accounts for half or more of total mass loss. Despite its importance, modeled meltwater runoff fluxes are poorly constrained, primarily due to a lack of direct in situ observations. Here, we present the first ever longitudinal (north-south) inter-comparison of a multi-year dataset (2004-2014) of discharge for four drainage basins - Watson, Akuliarusiarsuup Kuua, Naujat Kuat, and North Rivers - along West Greenland. These in situ hydrologic measurements are compared with modeled runoff output from Modèle Atmosphérique Régional (MAR) regional climate model, and the performance of the model is examined. An analysis of the relationship between modeled and actual ice sheet runoff patterns is assessed, and provides insight into the model's ability to capture inter-annual and intra-annual variability, spatiotemporal patterns, and extreme melt events. This study's findings will inform future development and parameterization of ice sheet surface mass balance models.

  10. Environmental Oil Spill Sensitivity Atlas for the Northern West Greenland (72°-75° N) Coastal Zone

    DEFF Research Database (Denmark)

    Stjernholm, Michael; Boertmann, David; Mosbech, Anders

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenland between 72º N and 75º N. The coastal zone is divided into 118 shoreline segments and the offshore zone into 3 areas. A sensitivity index value is calculated for each segment/area, and each segment....../area is subsequently ranked according to four degrees of sensitivity. Besides this general ranking a number of smaller areas are especially selected as they are of particular significance, they are especially vulnerable to oil spills and they have a size making oil spill response possible. The shoreline sensitivity....... Based on all the information, appropriate oil spill response methods have been assessed for each area...

  11. Environmental Oil Spill Sensitivity Atlas for the West Greenland (68°-72° N) Coastal Zone, 2nd revised edition

    DEFF Research Database (Denmark)

    Clausen, Daniel Spelling; Johansen, Kasper Lambert; Mosbech, Anders

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenland between 68º N and 72º N. The coastal zone is divided into 199 shoreline segments and the offshore zone into 8 areas. A sensitivity index value is calculated for each segment/area, and each segment....../area is subsequently ranked according to four degrees of sensitivity. Besides this general ranking a number of smaller areas are especially selected as they are of particular significance, they are especially vulnerable to oil spills and they have a size making oil spill response possible. The shoreline sensitivity....... Based on all the information, appropriate oil spill response methods have been assessed for each area....

  12. Spatial statistical analysis of contamination level of 241Am and 239Pu, Thule, North-West Greenland

    DEFF Research Database (Denmark)

    Strodl Andersen, Jens

    intensively. In Grønnedal the maximum observed level of 241Am is 1.9×104 Bq m-2. Prediction of the overall amount of 241Am and 239,240Pu is based on grid points within the range from the nearest measurement location. The overall amount is therefore highly dependent on the model. Under the optimal spatial......A spatial analysis of data on radioactive pollution on land at Thule, North-West Greenland is presented. The data comprises levels of 241Am and 239,240Pu on land. Maximum observed level of 241Am is 2.8×105 Bq m-2. Highest levels were observed near Narsaarsuk. This area was also sampled most...

  13. Spatial statistical analysis of contamination level of 241Am and 239Pu, Thule, North-West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Strodl Andersen, J. (JSA EnviroStat (Denmark))

    2011-10-15

    A spatial analysis of data on radioactive pollution on land at Thule, North-West Greenland is presented. The data comprises levels of 241Am and 239,240Pu on land. Maximum observed level of 241Am is 2.8x105 Bq m-2. Highest levels were observed near Narsaarsuk. This area was also sampled most intensively. In Groennedal the maximum observed level of 241Am is 1.9-104 Bq m-2. Prediction of the overall amount of 241Am and 239,240Pu is based on grid points within the range from the nearest measurement location. The overall amount is therefore highly dependent on the model. Under the optimal spatial model for Narsaarsuk, within the area of prediction, the predicted total amount of 241Am is 45 GBq and the predicted total amount of 239,240Pu is 270 GBq. (Author)

  14. Ice-margin and meltwater dynamics during the mid-Holocene in the Kangerlussuaq area of west Greenland

    DEFF Research Database (Denmark)

    Carrivick, Jonathan L.; Yde, Jacob; Russell, Andrew J.

    2017-01-01

    Land-terminating parts of the west Greenland ice sheet have exhibited highly dynamic meltwater regimes over the last few decades including episodes of extremely intense runoff driven by ice surface ablation, ponding of meltwater in an increasing number and size of lakes, and sudden outburst floods......, or jokulhlaups', from these lakes. However, whether this meltwater runoff regime is unusual in a Holocene context has not been questioned. This study assembled high-resolution topographical data, geological and landcover data, and produced a glacial geomorphological map covering similar to 1200km(2). Digital...... analysis of the landforms reveals a mid-Holocene land-terminating ice margin that was predominantly cold-based. This ice margin underwent sustained active retreat but with multiple minor advances. Over c.1000years meltwater runoff became impounded within numerous and extensive proglacial lakes...

  15. Increasing water vapor transport to the Greenland Ice Sheet revealed using self-organizing maps

    Science.gov (United States)

    Mattingly, Kyle S.; Ramseyer, Craig A.; Rosen, Joshua J.; Mote, Thomas L.; Muthyala, Rohi

    2016-09-01

    The Greenland Ice Sheet (GrIS) has been losing mass in recent decades, with an acceleration in mass loss since 2000. In this study, we apply a self-organizing map classification to integrated vapor transport data from the ERA-Interim reanalysis to determine if these GrIS mass loss trends are linked to increases in moisture transport to Greenland. We find that "moist" days (i.e., days featuring anomalously intense water vapor transport to Greenland) were significantly more common during 2000-2015 compared to 1979-1994. Furthermore, the two most intense GrIS melt seasons during the last 36 years were either preceded by a record percentage of moist winter days (2010) or occurred during a summer with a record frequency of moist days (2012). We hypothesize that moisture transport events alter the GrIS energy budget by increasing downwelling longwave radiation and turbulent fluxes of sensible and latent energy.

  16. Explaining the presence of perennial liquid water bodies in the firn of the Greenland Ice Sheet

    NARCIS (Netherlands)

    Kuipers Munneke, P.; Ligtenberg, S.R.M.; van den Broeke, M.R.; van Angelen, J.H.; Forster, R.R.

    2014-01-01

    Recent observations have shown that the firn layer on the Greenland Ice Sheet features subsurface bodies of liquid water at the end of the winter season. Using a model with basic firn hydrology, thermodynamics, and compaction in one dimension, we find that a combination of moderate to strong surface

  17. Paleomagnetism of Eocene Talerua Member Lavas on Hareøen Island, West Greenland

    DEFF Research Database (Denmark)

    Abrahamsen, N.; Schmidt, Anne G.; Riisager, P.

    2005-01-01

    remanent magnetic field direction, 13 individual readings of the paleomagnetic fields were obtained. The paleomagnetic pole with coordinates 76.3°N, 201.5°E (A95=7.4°, K=32.7, N=13) is in good accordance with paleomagnetic poles from other continents rotated back to Greenland using plate kinematic rotation...

  18. Contaminants in the atmosphere. AMAP-Nuuk, West Greenland 2002-2004

    Energy Technology Data Exchange (ETDEWEB)

    Skov, H.; Bossi, S.; Waehlin, P. [and others

    2005-08-15

    This report presents the results of atmospheric monitoring in Nuuk, Greenland. A long series of heavy metals and persistent organic Pollutants (POPs) have been measured and model calculations have been carried out supporting the interpretation of the results. Financially, the Danish Environmental Protection Agency supported this work with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region and the work is part of the Danish contribution to Arctic Monitoring and Assessment Programme, AMAP. (au)

  19. Changing surface–atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland

    OpenAIRE

    2015-01-01

    We present 5 years (2009–2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. – above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly negative surface mass budget (SMB) and surface meltwater run-off. The observed run-off was due to a large ice fraction in the upper 10 m of firn that prevented meltwat...

  20. 10Be dating reveals early-middle Holocene age of the Drygalski Moraines in central West Greenland

    Science.gov (United States)

    Cronauer, Sandra L.; Briner, Jason P.; Kelley, Samuel E.; Zimmerman, Susan R. H.; Morlighem, Mathieu

    2016-09-01

    We reconstruct the history of the Greenland Ice Sheet margin on the Nuussuaq Peninsula in central West Greenland through the Holocene using lake sediment analysis and cosmogenic 10Be exposure dating of the prominent Drygalski Moraines. Erratics perched on bedrock outboard of the Drygalski Moraines constrain local deglaciation to ∼9.9 ± 0.6 ka (n = 2). Three Drygalski Moraine crests yield mean 10Be ages of 8.6 ± 0.4 ka (n = 2), 8.5 ± 0.2 ka (n = 3), and 7.6 ± 0.1 ka (n = 2) from outer to inner. Perched erratics between the inner two moraines average 7.8 ± 0.1 ka (n = 2) and are consistent with the moraine ages. Sediments from a proglacial lake with a catchment area extending an estimated 2 km beneath (inland of) the present ice sheet terminus constrain an ice sheet minimum extent from 5.4 ka to 0.6 ka. The moraine chronology paired with the lake sediment stratigraphy reveals that the ice margin likely remained within ∼2 km of its present position from ∼9.9 to 5.4 ka. This unexpected early Holocene stability, preceded by rapid ice retreat and followed by minimum ice extent between ∼5.4 and 0.6 ka, contrasts with many records of early Holocene warmth and the Northern Hemisphere summer insolation maximum. We suggest ice margin stability may instead be tied to adjacent ocean temperatures, which reached an optimum in the middle Holocene.

  1. The intertidal community in West Greenland: Large-scale patterns and small-scale variation on ecosystem dynamics along a climate gradient

    DEFF Research Database (Denmark)

    Thyrring, Jakob; Blicher, Martin; Sejr, Mikael Kristian

    are largely unknown. The West Greenland coast is north - south orientated. This provides an ideal setting to study the impact of climate change on marine species population dynamics and distribution. We investigated the latitudinal changes in the rocky intertidal community along 18° latitudes (59-77°N......) in West Greenland. Using cleared quadrats we quantified patterns in abundance, biomass and species richness in the intertidal zone. We use this data to disentangle patterns in Arctic intertidal communities at different scales. We describe the effects of different environmental drivers and species...... interactions on distribution and dynamics of intertidal species. Our results indicate that changes in distribution and abundance of foundation species can have large effects on the ecosystem. We also show that the importance of small-scale variation may be of same magnitude as large- scale variation. Only...

  2. The optical properties of greenlandic coastal waters: Modelling light penetration in a changing climate

    DEFF Research Database (Denmark)

    Stedmon, Colin; Markager, S.S.; Pedersen, T.J.

    Greenlandic fjords are very productive and pristine ecosystems, which the local population is both intrinsically linked to and dependent on through heritage, industrial fisheries, and tourism. The availability and spectral quality of light are key parameters controlling the productivity of these ...... with a considerable amount of terrestrial dissolved organic matter (DOM) from the Arctic Ocean; and Godthåbsfjord a fjord in Southwest Greenland where strong tides ensure a regular supply of warm shelf water which melt glacial ice before it can leave the fjord...... depending on the influence of shelf water entering the fjords, extent of glacial ice melt and the size and vertical distribution of the phytoplankton biomass. In this study the data from two contrasting sites are compared: Young Sound, a fjord system in Northeast Greenland that imports shelf waters...... of these waters. Although solar elevation and sea ice cover play an important role, during the summer month’s light is also regulated by water constituents such as dissolved and particulate organic matter, phytoplankton and suspended sediments. The relative importance of each of these constituents varies...

  3. Inuit health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, P; Curtis, T; Borch-Johnsen, K

    2003-01-01

    During 1997-2001 a population survey was carried out amongst Greenland Inuit living in Denmark and West Greenland (Nuuk, Sisimiut, Qasigiannguit and four villages in Uummannaq municipality). Data collection comprised an interview, a questionnaire, clinical examinations and sampling of biological ...

  4. Spatial and temporal variations in high turbidity surface water off the Thule region, northwestern Greenland

    Science.gov (United States)

    Ohashi, Yoshihiko; Iida, Takahiro; Sugiyama, Shin; Aoki, Shigeru

    2016-09-01

    Glacial meltwater discharge from the Greenland ice sheet and ice caps forms high turbidity water in the proglacial ocean off the Greenland coast. Although the timing and magnitude of high turbidity water export affect the coastal marine environment, for example, through impacts on biological productivity, little is known about the characteristics of this high turbidity water. In this paper, we therefore report on the spatial and temporal variations in high turbidity water off the Thule region in northwestern Greenland, based on remote sensing reflectance data at a wavelength of 555 nm (Rrs555). The high turbidity area, identified on the basis of high reflectivity (Rrs555 ≥ 0.0070 sr-1), was generally distributed near the coast, where many outlet glaciers terminate in the ocean and on land. The extent of the high turbidity area exhibited substantial seasonal and interannual variability, and its annual maximum extent was significantly correlated with summer air temperature. Assuming a linear relationship between the high turbidity area and summer temperature, annual maximum extent increases under the influence of increasing glacial meltwater discharge, as can be inferred from present and predicted future warming trends.

  5. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Zircon geochronology from the Kangaatsiaq–Qasigiannguit region, the northern part of the 1.9–1.8 Ga Nagssugtoqidian orogen, West Greenland

    Directory of Open Access Journals (Sweden)

    Conelly, James N.

    2006-12-01

    Full Text Available The Kangaatsiaq–Qasigiannguit region in the northern part of the Palaeoproterozoic Nagssugtoqidian orogen of West Greenland consists of poly-deformed orthogneisses and minor occurrences of interleaved, discontinuous supracrustal belts. Laser ablation ICP-MS 207Pb/206Pb analyses of detrital zircons from four metasedimentary rocks (supplemented by ion probe analysis of one sample and igneous zircons from six granitoid rocks cutting metasedimentary units indicate that the supracrustal rocks in the Kangaatsiaq–Qasigiannguit (Christianshåb region are predominantly Archaean in age. Four occurrences of metasedimentary rocks are clearly Archaean, two have equivocal ages, and only one metasedimentary unit, from within the Naternaq (Lersletten supracrustal belt, is demonstrably Palaeoproterozoic and readily defines a large fold complex of this age at Naternaq. The 2.9–2.8 Ga ages of detrital Archaean grains are compatible with derivation from the local basement orthogneisses within the Nagssugtoqidian orogen. The detrital age patterns are similar to those of metasediments within the central Nagssugtoqidian orogen but distinct from age patterns in metasediments of the Rinkian belt to the north, where there is an additional component of pre-2.9 Ga zircons. Synkinematic intrusive granitoid rocks constrain the ages of some Archaean deformation at 2748 ± 19 Ma and some Palaeoproterozoic deformation at 1837 ± 12 Ma.

  6. Structure and annual increase in a population of West Greenland caribou (Rangifer tarandus groenlandicus

    Directory of Open Access Journals (Sweden)

    Henning Thing

    1982-05-01

    Full Text Available During 1977-80 a large scale research program was carried out in West Greenland to study caribou ecology and population dynamics. Papers dealing with feeding ecology, range condition, calf mortality, and behaviour have been published elsewhere (Strandgaard 1980; Holt 1980; Clausen et al. 1980; Thing & Clausen 1980; Thing 1980; Roby 1980; Thing 1981; Roby & Thing 1982; Thing & Thing 1982. The present study deals with some dynamic parameters in the Sisimiut herd (Fig. 1, viz. group size, sex and age composition, calf/cow ratio, calf increment, and annual recruitment. Caribou in the Sisimiut region are mainly found in very small groups of one to five animals in most seasons. Aggregations of more than 50 animals are rarely seen except in the calving and summer seasons (Fig. 2. A distinct annual cycle is apparent in the mean group size with a steady increase from a mid winter minimum of 1.4 caribou/group towards a maximum of almost 25 caribou/group in the post-calving season (Fig. 3. The absence of important predators (especially wolves and the fact that winter food resources in the region have been depleted seem to reduce group size. Consequently, Sisimiut caribou are characterized year round by forming very small groups as compared to most other wild Rangifer populations. Caribou cows (females 2 years + make up approx. 50% of the herd, while bulls (males 2 years + average only 10% (Fig. 4. The number of bulls in the herd shows a significant decline caused by a selective hunting pressure as well as natural winter mortality (Fig. 5. The rut takes place in October during the fall migration from the inland ranges adjacent to the Inland Ice towards the coast line. The cows are apparently served mainly by 1 1/2 and 2 year old bulls. Despite scarcity of adequate food on the winter ranges there is a high calf production. This is probably explained by excellent forage conditions on the inland range prior to and during the calving season (May - June

  7. Environmental Oil Spill Sensitivity Atlas for the West Greenland (68º-72º N) Coastal Zone

    DEFF Research Database (Denmark)

    Mosbech, A.; Boertmann, D.; Olsen, B. Ø.

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenlandbetween 68º N and 72º N. The coastal zone is divided into nearly 200 areas and the offshorezone into 8 areas. A sensitivity index value is calculated for each area, and each area issubsequently ranked...

  8. Heat sources for glacial ice melt in a West Greenland tidewater outlet glacier fjord: The role of subglacial freshwater discharge

    DEFF Research Database (Denmark)

    Bendtsen, Jørgen; Mortensen, John; Lennert, Kunuk

    2015-01-01

    The melting of tidewater outlet glaciers from the Greenland Ice Sheet contributes significantly to global sea level rise. Accelerated mass loss is related to melt-processes in front of calving glaciers, yet the role of ocean heat transports is poorly understood. Here we present the first direct...... measurements from a subglacial plume in front of a calving tidewater outlet glacier. Surface salinity in the plume corresponded to a meltwater content of 7 %, which is indicative of significant entrainment of warm bottom water and, according to plume model calculations, significant ice melt. Energy balance...... of the area near the glacier showed that ice melt was mainly due to ocean heat transport and that direct plume-associated melt was only important in periods with high meltwater discharge rates of ~100 m3 s−1. Ocean mixing outside of the plume area was thus the primary heat source for melting glacier ice....

  9. Heat sources for glacial ice melt in a West Greenland tidewater outlet glacier fjord: The role of subglacial freshwater discharge

    DEFF Research Database (Denmark)

    Bendtsen, Jørgen; Mortensen, John; Lennert, Kunuk

    2015-01-01

    The melting of tidewater outlet glaciers from the Greenland Ice Sheet contributes significantly to global sea level rise. Accelerated mass loss is related to melt-processes in front of calving glaciers, yet the role of ocean heat transports is poorly understood. Here we present the first direct...... measurements from a subglacial plume in front of a calving tidewater outlet glacier. Surface salinity in the plume corresponded to a meltwater content of 7 %, which is indicative of significant entrainment of warm bottom water and, according to plume model calculations, significant ice melt. Energy balance...... of the area near the glacier showed that ice melt was mainly due to ocean heat transport and that direct plume-associated melt was only important in periods with high meltwater discharge rates of ~100 m3 s−1. Ocean mixing outside of the plume area was thus the primary heat source for melting glacier ice....

  10. Partitioning of melt energy and meltwater fluxes in the ablation zone of the west Greenland ice sheet

    Directory of Open Access Journals (Sweden)

    M. Van den Broeke

    2008-08-01

    Full Text Available We present four years of surface mass balance data from the ablation zone of the west Greenland ice sheet along the 67° N latitude circle. Sonic height rangers and automatic weather stations continuously measured accumulation/ablation and near-surface climate at distances of 6, 38 and 88 km from the ice sheet margin at elevations of 490, 1020 and 1520 m a.s.l. Using a melt model and reasonable assumptions about snow density and percolation characteristics, these data are used to quantify the partitioning of energy and mass fluxes during melt episodes. The lowest site receives very little winter accumulation, and ice melting is nearly continuous in June, July and August. Due to the lack of snow accumulation, little refreezing occurs and virtually all melt energy is invested in runoff. Higher up the ice sheet, the ice sheet surface freezes up during the night, making summer melting intermittent. At the intermediate site, refreezing in snow consumes about 10% of the melt energy, increasing to 40% at the highest site. The sum of these effects is that total melt and runoff increase exponentially towards the ice sheet margin, each time doubling between the stations. At the two lower sites, we estimate that radiation penetration causes 20–30% of the ice melt to occur below the surface.

  11. Environmental oil spill sensitivity atlas for the West Greenland (68 deg.-72 deg. N) coastal zone, 2nd revised edition

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, D.; Johansen, Kasper L.; Mosbech, A.; Boertmann, D.; Wegeberg, S.

    2012-12-15

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenland between 68 deg. N and 72 deg. N. The coastal zone is divided into 199 shoreline segments and the offshore zone into 8 areas. A sensitivity index value is calculated for each segment/area, and each segment/area is subsequently ranked according to four degrees of sensitivity. Besides this general ranking a number of smaller areas are especially selected as they are of particular significance, they are especially vulnerable to oil spills and they have a size making oil spill response possible. The shoreline sensitivity ranking are shown on 37 maps (in scale 1:250,000), which also show the different elements included and the selected areas. Coast types, logistics and proposed response methods along the coasts are shown on another 37 maps. The sensitivities of the offshore zones are depicted on 4 maps, one for each season. Based on all the information, appropriate oil spill response methods have been assessed for each area. (Author)

  12. Modeling of ocean-induced ice melt rates of five west Greenland glaciers over the past two decades

    Science.gov (United States)

    Rignot, E.; Xu, Y.; Menemenlis, D.; Mouginot, J.; Scheuchl, B.; Li, X.; Morlighem, M.; Seroussi, H.; den Broeke, M. van; Fenty, I.; Cai, C.; An, L.; Fleurian, B. de

    2016-06-01

    High-resolution, three-dimensional simulations from the Massachusetts Institute of Technology general circulation model ocean model are used to calculate the subaqueous melt rate of the calving faces of Umiamako, Rinks, Kangerdlugssup, Store, and Kangilerngata glaciers, west Greenland, from 1992 to 2015. Model forcing is from monthly reconstructions of ocean state and ice sheet runoff. Results are analyzed in combination with observations of bathymetry, bed elevation, ice front retreat, and glacier speed. We calculate that subaqueous melt rates are 2-3 times larger in summer compared to winter and doubled in magnitude since the 1990s due to enhanced subglacial runoff and 1.6 ± 0.3°C warmer ocean temperature. Umiamako and Kangilerngata retreated rapidly in the 2000s when subaqueous melt rates exceeded the calving rates and ice front retreated to deeper bed elevation. In contrast, Store, Kangerdlugssup, and Rinks have remained stable because their subaqueous melt rates are 3-4 times lower than their calving rates, i.e., the glaciers are dominated by calving processes.

  13. Multi-Year Elevation Changes Near the West Margin of the Greenland Ice Sheet from Satellite Radar Altimetry

    Science.gov (United States)

    Lingle, Craig S.; Brenner, Anita C.; Zwally, H. Jay; DiMarzio, John P.

    1991-01-01

    Mean changes in the surface elevation near the west margin of the Greenland ice sheet are measured using Seasat altimetry and altimetry from the Geosat Exact Repeat Mission (ERM). The Seasat data extend from early July through early October 1978. The ERM data extend from winter 1986-87 through fall 1988. Both seasonal and multi-year changes are measured using altimetry referenced to GEM T2 orbits. The possible effects of orbit error are minimized by adjusting the orbits into a common ocean surface. Seasonal mean changes in the surface height are recognizable during the Geosat ERM. The multi-year measurements indicate the surface was lower by 0.4 +/- 0.4 m on average in late summer 1987 than in late summer 1978. The surface was lower by 0.2 +/- 0.5 m on average in late summer 1988 than in late summer 1978. As a control case, the computations art also carried out using altimetry referenced to orbits not adjusted into a common ocean surface.

  14. Mesozooplankton biomass data from the Kapisigdlit an inner fjord branch of the Godthaabsfjord system, West Greenland, 2010

    DEFF Research Database (Denmark)

    2013-01-01

    branch, in the middle of a shallower inner creek . St. 1-4 was covering deeper parts of the fjord, and St. 5 was located on the slope leading up to the shallow inner creek. Mesozooplankton was sampled by vertical net tows using a Hydrobios Multinet (type Mini) equipped with a flow meter and 50 µm mesh......Sampling was conducted from March 24 to August 5 2010, in the fjord branch Kapisigdlit located in the inner part of the Godthåbsfjord system, West Greenland. The vessel "Lille Masik" was used during all cruises except on June 17-18 where sampling was done from RV Dana (National Institute...... for Aquatic Resources, Denmark). A total of 15 cruises (of 1-2 days duration) 7-10 days apart was carried out along a transect composed of 6 stations (St.), spanning the length of the 26 km long fjord branch. St. 1 was located at the mouth of the fjord branch and St. 6 was located at the end of the fjord...

  15. Partitioning of melt energy and meltwater fluxes in the ablation zone of the west Greenland ice sheet

    Directory of Open Access Journals (Sweden)

    M. van den Broeke

    2008-12-01

    Full Text Available We present four years (August 2003–August 2007 of surface mass balance data from the ablation zone of the west Greenland ice sheet along the 67° N latitude circle. Sonic height rangers and automatic weather stations continuously measured accumulation/ablation and near-surface climate at distances of 6, 38 and 88 km from the ice sheet margin at elevations of 490, 1020 and 1520 m a.s.l. Using a melt model and reasonable assumptions about snow density and percolation characteristics, these data are used to quantify the partitioning of energy and mass fluxes during melt episodes. The lowest site receives very little winter accumulation, and ice melting is nearly continuous in June, July and August. Due to the lack of snow accumulation, little refreezing occurs and virtually all melt energy is invested in runoff. Higher up the ice sheet, the ice sheet surface freezes up during the night, making summer melting intermittent. At the intermediate site, refreezing in snow consumes about 10% of the melt energy, increasing to 40% at the highest site. The sum of these effects is that total melt and runoff increase exponentially towards the ice sheet margin, each time doubling between the stations. At the two lower sites, we estimate that radiation penetration causes 20–30% of the ice melt to occur below the surface.

  16. Atmospheric concentrations of organochlorine pesticides, polybrominated diphenyl ethers and polychloronaphthalenes in Nuuk, South-West Greenland

    DEFF Research Database (Denmark)

    Bossi, Rossana; Skov, Henrik; Vorkamp, Katrin

    2008-01-01

    Atmospheric concentrations of organochlorine pesticides (OCs), polybrominated diphenyl ethers (PBDEs) and polychloronaphthalenes (PCNs) were measured for the first time in Nuuk, Greenland in 2004 and 2005. The annual mean concentrations af the measured OCs were: α-HCH 20.2 pg m-3, Υ-HCH (lindane) 5......-HCH, which had maximum concentration in August in both years. The average annual mean for ΣPBDEs was 1.14 ± 0.81 pg m-3. The predominant congeners measured in Nuuk were BDE-47 and BDE-99 followed by BDE-100, -153 and -28, indicating the use of penta-BDE technical products as the main source. A clear seasonal......) and the penta-PCNs (18% of the annual mean). A seasonal trend for ∑PCNs was not observed. Atmospheric concentrations of the investigated compounds were correlated with temperature and anthropogenic CO in order to obtain information about their transport pattern. Positive correlations were found between CO...

  17. The crustal uplift determined at the Jakobshavn glacier (West Greenland) using ATM and GPS data

    DEFF Research Database (Denmark)

    Muresan, Ioana Stefania; Frumosu, Flavia Dalia; Khan, Shfaqat Abbas

    The Greenland ice sheet has experienced record melting in recent years. In order to estimate the ice loss we can make use of the earth’s natural elasticity to weigh the ice. Ice bends down the bedrock so when the ice melts away, the bedrock rises measurably in response. Throughout this abstract we...... present both a predicted and observed crustal upliftfor the Jakobshavn glacier using ATM data (Airborne Topographic Mapper) from NASA ATM flights during 1997, 2005 and 2010 supplemented with data provided from continuous Global Positioning System (GPS), measurements made on bedrock between 2005...... value was 16.321 mm/yr, forILAS 1.74 mm/yr and 1.53 mm/yr, for QEAS-0.189 mm/yr and 1.15 mm/yr. That being adifference of 4.701 mm/yr is found forKAAS, 0.21 mm/yr for ILAS and 1.339mm/yr for QEAS. The uncertaintiesassociated both with the ATM and GPSresults are 0.8 mm/yr for ATM and 0.5mm/yr for GPS...

  18. Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland

    DEFF Research Database (Denmark)

    Charalampidis, C.; Van As, D.; Box, J. E.

    2015-01-01

    negative surface mass budget (SMB) and surface meltwater run-off. The observed run-off was due to a large ice fraction in the upper 10 m of firn that prevented meltwater from percolating to available pore volume below. Analysis reveals an anomalously low 2012 summer-averaged albedo of 0.71 (typically ∼ 0.......78), as meltwater was present at the ice sheet surface. Consequently, during the 2012 melt season, the ice sheet surface absorbed 28 % (213 MJ m-2) more solar radiation than the average of all other years. A surface energy balance model is used to evaluate the seasonal and interannual variability of all surface......We present 5 years (2009-2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l.-above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly...

  19. Water use in engineering dormitory in Greenland - Apisseq

    DEFF Research Database (Denmark)

    Kotol, Martin

    The report contains information about the annual water use in the engineering dormitory Apisseq. The report begins with brief description of the dormitory and then presents the water use, its fractions (cold water and DHW) and also the energy use related to DHW heating. Significant portion...

  20. Changing surface–atmosphere energy exchange and refreezing capacity of the lower accumulation area, west Greenland

    Directory of Open Access Journals (Sweden)

    C. Charalampidis

    2015-05-01

    Full Text Available We present five years (2009–2013 of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. of the ice sheet in the Kangerlussuaq region, western Greenland. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly negative surface mass budget (SMB and surface meltwater runoff. The observed runoff was due to a large ice fraction in the upper 10 m of firn that prevented meltwater from percolating to available pore volume below. Analysis reveals a relatively low 2012 summer albedo of ~0.7 as meltwater was present at the surface. Consequently, during the 2012 melt season the surface absorbed 29% (213 MJ m-2 more solar radiation than the average of all other years. A surface energy balance model is used to evaluate the seasonal and interannual variability of all surface energy fluxes. The model reproduces the observed melt rates as well as the SMB for each season. A sensitivity test reveals that 71% of the additional solar radiation in 2012 was used for melt, corresponding to 36% (0.64 m of the 2012 surface lowering. The remaining 1.14 m was primarily due to the high atmospheric temperatures up to +2.6 °C daily average, indicating that 2012 would have been a negative SMB year at this site even without the melt-albedo feedback. Longer time series of SMB, regional temperature and remotely sensed albedo (MODIS show that 2012 was the first strongly negative SMB year with the lowest albedo at this elevation on record. The warm conditions of the last years resulted in enhanced melt and reduction of the refreezing capacity at the lower accumulation area. If high temperatures continue the current lower accumulation area will turn into a region with superimposed ice in coming years.

  1. Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland

    Science.gov (United States)

    Charalampidis, C.; van As, D.; Box, J. E.; van den Broeke, M. R.; Colgan, W. T.; Doyle, S. H.; Hubbard, A. L.; MacFerrin, M.; Machguth, H.; Smeets, C. J. P. P.

    2015-11-01

    We present 5 years (2009-2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. - above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly negative surface mass budget (SMB) and surface meltwater run-off. The observed run-off was due to a large ice fraction in the upper 10 m of firn that prevented meltwater from percolating to available pore volume below. Analysis reveals an anomalously low 2012 summer-averaged albedo of 0.71 (typically ~ 0.78), as meltwater was present at the ice sheet surface. Consequently, during the 2012 melt season, the ice sheet surface absorbed 28 % (213 MJ m-2) more solar radiation than the average of all other years. A surface energy balance model is used to evaluate the seasonal and interannual variability of all surface energy fluxes. The model reproduces the observed melt rates as well as the SMB for each season. A sensitivity analysis reveals that 71 % of the additional solar radiation in 2012 was used for melt, corresponding to 36 % (0.64 m) of the 2012 surface lowering. The remaining 64 % (1.14 m) of surface lowering resulted from high atmospheric temperatures, up to a +2.6 °C daily average, indicating that 2012 would have been a negative SMB year at this site even without the melt-albedo feedback. Longer time series of SMB, regional temperature, and remotely sensed albedo (MODIS) show that 2012 was the first strongly negative SMB year, with the lowest albedo, at this elevation on record. The warm conditions of recent years have resulted in enhanced melt and reduction of the refreezing capacity in the lower accumulation area. If high temperatures continue, the current lower accumulation area will turn into a region with superimposed ice in coming years.

  2. Glacial meltwater and primary production are drivers of strong CO2 uptake in fjord and coastal waters adjacent to the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    L. Meire

    2015-04-01

    Full Text Available The Greenland Ice Sheet releases large amounts of freshwater, which strongly influences the physical and chemical properties of the adjacent fjord systems and continental shelves. Glacial meltwater input is predicted to strongly increase in the future, but the impact of meltwater on the carbonate dynamics of these productive coastal systems remains largely unquantified. Here we present seasonal observations of the carbonate system over the year 2013 in the surface waters of a west Greenland fjord (Godthåbsfjord influenced by tidewater outlet glaciers. Our data reveal that the surface layer of the entire fjord and adjacent continental shelf are undersaturated in CO2 throughout the year. The average annual CO2 uptake within the fjord is estimated to be 65 g C m−2 yr−1, indicating that the fjord system is a strong sink for CO2. The largest CO2 uptake occurs in the inner fjord near to the Greenland Ice Sheet and high glacial meltwater input during the summer months correlates strongly with low pCO2 values. This strong CO2 uptake can be explained by the thermodynamic effect on the surface water pCO2 resulting from the mixing of fresh glacial meltwater and ambient saline fjord water, which results in a CO2 uptake of 1.8 mg C kg−1 of glacial ice melted. We estimated that 28% of the CO2 uptake can be attributed to the input of glacial meltwater, while the remaining part is due to high primary production. Our findings imply that glacial melt\\-water is an important driver for undersaturation in CO2 in fjord and coastal waters adjacent to large ice sheets.

  3. Overlap in diet and distribution of two goose species suggests potential for competition at a common moulting area in West Greenland

    DEFF Research Database (Denmark)

    Raundrup, Katrine; Levermann, Nette; Poulsen, Michael

    2012-01-01

    decreased over the last 15-20 years, while the Canada Goose, a species new to the area, has increased. This study explores the overlap in diet and space use of these species in Mudderbugten and Kvandalen, together with factors that could influence the degree of competition between the two species. Data...... on activity budgets and spatial distribution were obtained from observations of behaviour, and diet selection was determined through analyses of plant epidermal fragments in faecal samples that were subsequently genotyped to goose species. No differences in diet or spatial distribution of the two species were......Inter-specific competition can occur where two or more species overlap in diet and/or spatial distribution. Such interactions might be most prevalent where a species invades areas previously occupied by another species. In West Greenland, the number of native Greenland White-fronted Geese has...

  4. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: 207Pb-206Pb dating of magnetite, monazite and allanite in the central and northern Nagssugtoqidian orogen, West Greenland

    Directory of Open Access Journals (Sweden)

    Frei, Robert

    2006-12-01

    Full Text Available Pb-isotopic data for magnetite from amphibolites in the Nagssugtoqidian orogen, central West Greenland, have been used to trace their source characteristics and the timing of metamorphism. Analyses of the magnetite define a Pb-Pb isochron age of 1726 ± 7 Ma. The magnetite is metamorphic in origin, and the 1726 Ma age is interpreted as a cooling age through the closing temperature of magnetite at ~600°C. Some of the amphibolites in this study come from the Naternaq supracrustal rocks in the northern Nagssugtoqidian orogen, which host the Naternaq sulphide deposit and may be part ofthe Nordre Strømfjord supracrustal suite, which was deposited at around 1950 Ma ago.Pb-isotopic signatures of magnetite from the Arfersiorfik quartz diorite in the central Nagssugtoqidian orogen are compatible with published whole-rock Pb-isotopic data from this suite; previous work has shown that it is a product of subduction-related calc-alkaline magmatism between 1920 and 1870 Ma. Intrusion of pegmatites occurred at around 1800 Ma in both the central and the northernparts of the orogen. Pegmatite ages have been determined by Pb stepwise leaching analyses of allanite and monazite, and source characteristics of Pb point to an origin of the pegmatites by melting of the surrounding late Archaean and Palaeoproterozoic country rocks. Hydrothermal activity took place after pegmatite emplacement and continued below the closure temperature of magnetite at 1800–1650 Ma. Because of the relatively inert and refractory nature of magnetite, Pb-isotopic measurements from this mineral may be of help to understand the metamorphic evolution of geologicallycomplex terrains.

  5. Thin-layer effects in glaciological seismic amplitude-versus-angle (AVA analysis: implications for characterising a subglacial till unit, Russell Glacier, West Greenland

    Directory of Open Access Journals (Sweden)

    A. D. Booth

    2012-08-01

    Full Text Available Seismic amplitude-versus-angle (AVA methods are a powerful means of quantifying the physical properties of subglacial material, but serious interpretative errors can arise when AVA is measured over a thinly-layered substrate. A substrate layer with a thickness less than 1/4 of the seismic wavelength, λ, is considered "thin", and reflections from its bounding interfaces superpose and appear in seismic data as a single reflection event. AVA interpretation of subglacial till can be vulnerable to such thin-layer effects, since a lodged (non-deforming till can be overlain by a thin (metre-scale cap of dilatant (deforming till. We assess the potential for misinterpretation by simulating seismic data for a stratified subglacial till unit, with an upper dilatant layer between 0.1–5.0 m thick (λ / 120 to > λ / 4, with λ = 12 m. For dilatant layers less than λ / 6 thick, conventional AVA analysis yields acoustic impedance and Poisson's ratio that indicate contradictory water saturation. A thin-layer interpretation strategy is proposed, that accurately characterises the model properties of the till unit. The method is applied to example seismic AVA data from Russell Glacier, West Greenland, in which characteristics of thin-layer responses are evident. A subglacial till deposit is interpreted, having lodged till (acoustic impedance = 4.26±0.59 × 106 kg m−2 s−1 underlying a water-saturated dilatant till layer (thickness < 2 m, Poisson's ratio ~ 0.5. Since thin-layer considerations offer a greater degree of complexity in an AVA interpretation, and potentially avoid misinterpretations, they are a valuable aspect of quantitative seismic analysis, particularly for characterising till units.

  6. Modelling the response of stable water isotopes in Greenland precipitation to orbital configurations of the previous interglacial

    Directory of Open Access Journals (Sweden)

    Jesper Sjolte

    2014-09-01

    Full Text Available The relation between δ 18O of precipitation and temperature has been used in numerous studies to reconstruct past temperatures at ice core sites in Greenland and Antarctica. During the past two decades, it has become clear that the slope between δ 18O and temperature varies in both space and time. Here, we use a general circulation model driven by changes in orbital parameters to investigate the Greenland δ 18O–temperature relation for the previous interglacial, the Eemian. In our analysis, we focus on changes in the moisture source regions, and the results underline the importance of taking the seasonality of climate change into account. The orbitally driven experiments show that continental evaporation over North America increases during summer in the warm parts of the Eemian, while marine evaporation decreases. This likely flattens the Greenland δ 18O response to temperature during summer. Since the main climate change in the experiments occurs during summer this adds to a limited response of δ 18O, which is more strongly tied to temperature during winter than during summer. A south–west to north–east gradient in the δ 18O–temperature slope is also evident for Greenland, with low slopes in the south–west and steeper slopes in the north–east. This probably reflects the proportion of continental moisture and Arctic moisture arriving in Greenland, with more continental moisture in the south–west and less in the north–east, and vice versa for the Arctic moisture.

  7. Environmental Oil Spill Sensitivity Atlas for the West Greenland (68º-72º N) Coastal Zone

    DEFF Research Database (Denmark)

    Mosbech, A.; Boertmann, D.; Olsen, B. Ø.

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenlandbetween 68º N and 72º N. The coastal zone is divided into nearly 200 areas and the offshorezone into 8 areas. A sensitivity index value is calculated for each area, and each area issubsequently ranked...... according to four degrees of sensitivity. Besides this general ranking anumber of smaller areas are especially selected because they are of particular significance, theyare particularly vulnerable to oil spill and, an effective oil spill response can be performed. Theshoreline sensitivity ranking is shown....... Based on all the information,appropriate oil spill response methods have been assessed for each area. Web site environmental-atlas.dmu.dk/...

  8. Continuous monitoring of summer surface water vapor isotopic composition above the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    H. C. Steen-Larsen

    2013-05-01

    Full Text Available We present here surface water vapor isotopic measurements conducted from June to August 2010 at the NEEM (North Greenland Eemian Drilling Project camp, NW Greenland (77.45° N, 51.05° W, 2484 m a.s.l.. Measurements were conducted at 9 different heights from 0.1 m to 13.5 m above the snow surface using two different types of cavity-enhanced near-infrared absorption spectroscopy analyzers. For each instrument specific protocols were developed for calibration and drift corrections. The inter-comparison of corrected results from different instruments reveals excellent reproducibility, stability, and precision with a standard deviations of ~ 0.23‰ for δ18O and ~ 1.4‰ for δD. Diurnal and intraseasonal variations show strong relationships between changes in local surface humidity and water vapor isotopic composition, and with local and synoptic weather conditions. This variability probably results from the interplay between local moisture fluxes, linked with firn–air exchanges, boundary layer dynamics, and large-scale moisture advection. Particularly remarkable are several episodes characterized by high (> 40‰ surface water vapor deuterium excess. Air mass back-trajectory calculations from atmospheric analyses and water tagging in the LMDZiso (Laboratory of Meteorology Dynamics Zoom-isotopic atmospheric model reveal that these events are associated with predominant Arctic air mass origin. The analysis suggests that high deuterium excess levels are a result of strong kinetic fractionation during evaporation at the sea-ice margin.

  9. Water volume estimates of the Greenland Perennial Firn Aquifer from in situ measurements

    Science.gov (United States)

    Koenig, L.; Miege, C.; Forster, R. R.; Brucker, L.

    2013-12-01

    Improving our understanding of the complex Greenland hydrologic system is necessary for assessing change across the Greenland Ice Sheet and its contribution to sea level rise (SLR). A new component of the Greenland hydrologic system, a Perennial Firn Aquifer (PFA), was recently discovered in April 2011. The PFA represents a large storage of liquid water within the Greenland Ice Sheet with an area of 70,000 × 10,000 km2 simulated by the RACMO2/GR regional climate model which closely follows airborne radar-derived mapping (Forster et al., in press). The average top surface depth of the PFA as detected by radar is 23 m. In April 2013, our team drilled through the PFA for the first time to gain an understanding of firn structure constraining the PFA, to estimate the water volume within the PFA, and to measure PFA temperatures and densities. At our drill site in Southeast Greenland (~100 km Northwest of Kulusuk), water fills or partially fills the available firn pore space from depths of ~12 to 37 m. The temperature within the PFA depths is constant at 0.1 × 0.1° C while the 12 m of seasonally dry firn above the PFA has a temperature profile dominated by surface temperature forcing. Near the bottom of the PFA water completely fills available pore space as the firn is compressed to ice entrapping water filled bubbles, as opposed to air filled bubbles, which then start to refreeze. A PFA maximum density is reached as the water filling the pore space, increasing density, begins refreezing back into ice at a lower density. We define this depth as the pore water refreeze depth and use this depth as the bottom of the PFA to calculate volume. It is certain, however that a small amount of water does exist below this depth, which we do not account for. The density profile obtained from the ACT11B firn core, the closest seasonally dry firn core, is compared to both gravitational densities and high resolution densities derived from a neutron density probe at the PFA site. The

  10. K West integrated water treatment system subproject safety analysis document

    Energy Technology Data Exchange (ETDEWEB)

    SEMMENS, L.S.

    1999-02-24

    This Accident Analysis evaluates unmitigated accident scenarios, and identifies Safety Significant and Safety Class structures, systems, and components for the K West Integrated Water Treatment System.

  11. Marine meiofauna, carbon and nitrogen mineralization in sandy and soft sediments of Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Rysgaard, S.; Christensen, P.B.; Sørensen, Martin Vinther

    2000-01-01

    layers of the sediment. Algal photosynthetic activity and nitrogen uptake reduced nitrogen effluxes and denitrification rates. Sulfate reduction was the most important pathway for carbon mineralization in the sediments of the shallow-water station. In contrast, high bottom-water NO3- concentrations...... and a relatively deep O-2 penetration into the sediment at the deep-water stations ensured high denitrification activity, particularly as a result of an efficient coupling between nitrification and denitrification. Denitrification accounted for up to 33 % of total carbon mineralization in the deep-water sediment......, corresponding to the 3 times higher number of meiofauna found in the upper 2 cm of this sediment. Thus, meiofauna increased the transport of solutes as compared to molecular diffusion by a factor of 1.5 to 3.1, thereby stimulating microbial mineralization...

  12. Photobiology of sea ice algae during initial spring growth in Kangerlussuaq, West Greenland: insights from imaging variable chlorophyll fluorescence of ice cores.

    Science.gov (United States)

    Hawes, Ian; Lund-Hansen, Lars Chresten; Sorrell, Brian K; Nielsen, Morten Holtegaard; Borzák, Réka; Buss, Inge

    2012-06-01

    We undertook a series of measurements of photophysiological parameters of sea ice algae over 12 days of early spring growth in a West Greenland Fjord, by variable chlorophyll fluorescence imaging. Imaging of the ice-water interface showed the development of ice algae in 0.3-0.4 mm wide brine channels between laminar ice crystals in the lower 4-6 mm of the ice, with a several-fold spatial variation in inferred biomass on cm scales. The maximum quantum yield of photosynthesis, F(v) /F(m), was initially low (~0.1), though this increased rapidly to ~0.5 by day 6. Day 6 also saw the onset of biomass increase, the cessation of ice growth and the time at which brine had reached -2 °C. We interpret this as indicating that the establishment of stable brine channels at close to ambient salinity was required to trigger photosynthetically active populations. Maximum relative electron transport rate (rETR(max)), saturation irradiance (E(k)) and photosynthetic efficiency (α) had also stabilised by day 6 at 5-6 relative units, ~30 μmol photons m⁻² s⁻¹ and 0.4-0.5 μmol photons m⁻²s⁻¹, respectively. E(k) was consistent with under-ice irradiance, which peaked at a similar value, confirming that daytime irradiance was adequate to facilitate photosynthetic activity throughout the study period. Photosynthetic parameters showed no substantial differences with depth within the ice, nor variation between cores or brine channels suggesting that during this early phase of ice algal growth cells were unaffected by gradients of environmental conditions within the ice. Variable chlorophyll fluorescence imaging offers a tool to determine how this situation may change over time and as brine channels and algal populations evolve.

  13. Persistent organic pollutants and methoxylated polybrominated diphenyl ethers in different tissues of white-tailed eagles (Haliaeetus albicilla) from West Greenland

    OpenAIRE

    2013-01-01

    We investigated polychlorinated biphenyls (PCBs), organochlorine pesticides (e.g. dichlorodiphenyltrichloroethane (DDT)), polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO-PBDEs), in six matrices (muscle, liver, kidney, adipose, blood, preen oil) of 17 white-tailed eagles from West Greenland sampled between 1997 and 2009. High inter-individual variation in contamination was found (PCBs: 0.49–1500 µg/g lipid weight (lw), DDTs: 0.23–910 µg/g lw, PBDEs: 0.01–24 µg/g lw, MeO-PBDE...

  14. Mapping of a Hydrological Ice Sheet Drainage Basin on the West Greenland Ice Sheet Margin from ERS-1/2 SAR Interferometry, Ice-Radar Measurement, and Modelling

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Bøggild, C.E.; Stenseng, L.

    2002-01-01

    The hydrological ice-sheet basin draining into the Tasersiaq lake, West Greenland (66°13'N, 50°30'W), was delineated, First using standard digital elevation models (DEMs) for ice-sheet surface and bedrock, and subsequently using a new high-resolution dataset, with a surface DEM derived from repeat...... importance of the potential of the ice overburden pressure compared to the bedrock topography. The meltwater run-off for the basin delineations was modelled with an energy-balance model calibrated with observed ice-sheet ablation and compared to a 25 year time series of measured basin run-off. The standard...

  15. Growth, condition, and mortality of caribou (Rangifer tarandus groenlandicus in the Sisimiut Population, West Greenland

    Directory of Open Access Journals (Sweden)

    Vidar Holthe

    1984-05-01

    Full Text Available Growth and condition of the Sisimiut caribou was anlysed by means of mandible length, carcass weight, and back fat indices. Mandible lenght showed unchanged growth conditions since the late 1960s, and growth stops at 4 years of age. The Sisimiut caribou seems to be smaller than North American caribous, Greenlandic semi-domesticated reindeer and of same size or smaller than Scandinavian reindeer. Carcass weight showed similar results, however cow growth rate seems not to prolong sexual maturation. Back fat deposits were less than what is known from other reindeer and caribou populations. Sex and age distribution of mandibles from various materials and survival curves based on the same material shows — an uneven distribution between bulls and cows and a relatively large proportion of old cows in the bag from the last years, which seems to be caused by a light hunting pressure when the population peaked in the 1960s. Heavy natural mortality for animals born before or after a winter with unfavorable snow conditions was also showed.Vækst, kondition og dødelighed hos vildren (Rangifer tarandus groenlandicus i Sisimiut-bestanden, Vestgrønland.Abstract in Danish / Sammendrag: Vækst- og konditionsforhold for Sisimiut-vildrenbestanden i Vestgrønland er beskrevet ved hjæip af underkæbelængde, slagtevægt og rygfedt. Undersøgelsen af kæbelængde viste, at vækstforholdene havde været uforandret siden sidste halvdel af 1960-erne, at væksten standser ved 4-års alderen, samt at Sisimiut-vildrenen er mindre end de nordamerikanske caribou, Itinnera-tamrenen og på størrelse med eller mindre end skandinaviske rensdyr. Dette viste sig også ved sammenligninger af slagtevægt. Vægten af simlerne er dog ikke så ringe, at der kan iagttages nogen forsinkelse i kønsmodningen. Fedtreserverne ved indgangen til vinteren synes at være dårligere end i andre undersøgte rensdyrbestande. Køns- og aldersfordelingen blandt forskellige typer af indsamlet k

  16. A cascade of warming impacts brings bluefin tuna to Greenland waters.

    Science.gov (United States)

    MacKenzie, Brian R; Payne, Mark R; Boje, Jesper; Høyer, Jacob L; Siegstad, Helle

    2014-08-01

    Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predator-prey dynamics in food webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species in ecological isolation from others. Here, we show that a large highly migratory top predator fish species has entered a high latitude subpolar area beyond its usual range. Bluefin tuna, Thunnus thynnus Linnaeus 1758, were captured in waters east of Greenland (65°N) in August 2012 during exploratory fishing for Atlantic mackerel, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9-11 °C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed to a warming trend since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species to the region. We conclude that a cascade of climate change impacts is restructuring the food web in east Greenland waters.

  17. Bio- and aminostratigraphy of some Quaternary marine deposits in West Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Simonarson, Leifur A.

    1984-01-01

    age. The mollusc faunas at the sites are distinctly different, although all reflect influx of some subarctic water into Baffin Bay. The fauna from Patorffk is the most diverse subfossil Quaternary fauna known from Baffin Bay. Such species as Panopea Ilorvegica and Balanus hameri indicate conditions...... warmer than the present, although no identical faunal assemblages are known. The fauna at Laksebugt is similar to modem faunas, but the dominating Portlandia arctica and Macoma moesta indicate a climate somewhat colder than the present, and Mytilus edulis suggests the presence of subarctic water...

  18. Self-regulation of ice flow varies across the ablation area in South-West Greenland

    NARCIS (Netherlands)

    Van De Wal, R. S. W.; Smeets, C. J. P. P.; Boot, W.; Stoffelen, M.; Van Kampen, R.; Doyle, S.; Wilhelms, F.; Van Den Broeke, M. R.; Reijmer, C. H.; Oerlemans, J.; Hubbard, A.

    2014-01-01

    The concept of a positive feedback between ice flow and enhanced melt rates in a warmer climate fuelled the debate regarding the temporal and spatial controls on seasonal ice acceleration. Here we combine melt, basal water pressure, and ice velocity data. We show using twenty years of data covering

  19. Self-regulation of ice flow varies across the ablation area in South-West Greenland

    NARCIS (Netherlands)

    Van De Wal, R. S. W.|info:eu-repo/dai/nl/101899556; Smeets, C. J. P. P.|info:eu-repo/dai/nl/191522236; Boot, W.; Stoffelen, M.; Van Kampen, R.; Doyle, S.; Wilhelms, F.; Van Den Broeke, M. R.; Reijmer, C. H.|info:eu-repo/dai/nl/229345956; Oerlemans, J.|info:eu-repo/dai/nl/06833656X; Hubbard, A.

    2014-01-01

    The concept of a positive feedback between ice flow and enhanced melt rates in a warmer climate fuelled the debate regarding the temporal and spatial controls on seasonal ice acceleration. Here we combine melt, basal water pressure, and ice velocity data. We show using twenty years of data covering

  20. Self-regulation of ice flow varies across the ablation area in south-west Greenland

    NARCIS (Netherlands)

    van de Wal, R. S. W.; Smeets, C. J. P. P.; Boot, W.; Stoffelen, M.; van Kampen, R.; Doyle, S. H.; Wilhelms, F.; van den Broeke, M. R.; Reijmer, C. H.; Oerlemans, J.; Hubbard, A.

    2015-01-01

    The concept of a positive feedback between ice flow and enhanced melt rates in a warmer climate fuelled the debate regarding the temporal and spatial controls on seasonal ice acceleration. Here we combine melt, basal water pressure and ice velocity data. Using 20 years of data covering the whole

  1. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Structural analysis of the northern Nagssugtoqidian orogen, West Greenland: an example of complex tectonic patterns in reworked high-grade metamorphic terrains

    Directory of Open Access Journals (Sweden)

    Mazur, Stanislaw

    2006-12-01

    Full Text Available Structural analysis of the deeply eroded northern flank of the Palaeoproterozoic Nagssugtoqidian orogen shows marked regional variations in both the orientation and type of fabrics, as is characteristic of Precambrian high-grade terrains subjected to polyphase deformation. Here we investigate the relationship between strain, metamorphic grade, and the resulting structural patterns. The study area south of Aasiaat in West Greenland consists of amphibolite- togranulite-gradeArchaean orthogneisses and relatively thin supracrustal units. The regional foliation displays a WSW–ENE to SW–NE strike associated with steep to moderate dips towards the WNW or SSE. Lineation trends are WSW–ENE and generally plunge gently towards the WSW. Mesoscopic fold hinges are usually colinear with the regional lineation. A systematic change in the plunge of lineations occurs across the south-western part of the study area. Towards the south, the lineation plunge progressively increases, despite the generally uniform strike of foliation. This southward increase of lineation pitch is typically associated with the transition from L > S or L = S shape fabrics in rocks characterised by a low pitch, to S > L or S fabrics in the zone of moderate to high pitch. The structural patterns point to subdivision of the study area into a southern domain mostly characterised by S or S > L shape fabrics and a moderate to high angle of lineation pitch, and a northern domain showing L > S or L = S fabrics and low angles of lineation pitch. This subdivision corresponds well with the map scale boundary between granulite facies rocks in the south and amphibolite facies rocks farther north. The observed structural pattern may be explained by two alternative tectonic models: (1 northward indentation of the previously cooled granulite block into the rheologically weaker amphibolite domain, and (2 strain partitioning within a mid-crustal transpression zone. In model 2 the northern domain

  2. Influence of sea ice on ocean water vapor isotopes and Greenland ice core records

    Science.gov (United States)

    Klein, Eric S.; Welker, Jeffrey M.

    2016-12-01

    A warming climate results in sea ice loss and impacts to the Arctic water cycle. The water isotope parameter deuterium excess, a moisture source proxy, can serve as a tracer to help understand hydrological changes due to sea ice loss. However, unlocking the sea ice change signal of isotopes from ice cores requires understanding how sea ice changes impact deuterium excess, which is unknown. Here we present the first isotope data linking a gradient of sea ice extents to oceanic water vapor deuterium excess values. Initial loss of sea ice extent leads to lower deuterium excess moisture sources, and then values progressively increase with further ice loss. Our new process-based interpretation suggests that past rapid (1-3 years) Greenland ice core changes in deuterium excess during warming might not be the result of abrupt atmospheric circulation shifts, but rather gradual loss of sea ice extent at northern latitude moisture sources.

  3. Oxidation-state distribution of plutonium in surface and subsurface waters at Thule, northwest Greenland

    DEFF Research Database (Denmark)

    McMahon, C.A.; Vintró, L.L.; Mitchell, P.I.

    2000-01-01

    chemical form) is present as fully dissolved species. Most of this plutonium would seem to be of weapons fallout origin, as the mean Pu-238/Pu-239,Pu-240 activity ratio in the water column (dissolved phase) at Thule (0.06 +/- 0.02; n = 10) is similar to the global fallout ratio at this latitude......The speciation of plutonium in Arctic waters sampled on the northwest Greenland shelf in August 1997 is discussed in this paper. Specifically, we report the results of analyses carried out on seawater sampled (a) close to the Thule air base where, in 1968, a US military aircraft carrying four......(V, VI) (mean, 68 +/- 6%; n = 6), with little if any distinction apparent between surface and bottom waters. Further, the oxidation state distribution at stations close to the accident site is similar to that measured at Upernavik, remote from this site. It is also similar to the distribution observed...

  4. Self-regulation of ice flow varies across the ablation area in south-west Greenland

    Science.gov (United States)

    van de Wal, R. S. W.; Smeets, C. J. P. P.; Boot, W.; Stoffelen, M.; van Kampen, R.; Doyle, S. H.; Wilhelms, F.; van den Broeke, M. R.; Reijmer, C. H.; Oerlemans, J.; Hubbard, A.

    2015-04-01

    The concept of a positive feedback between ice flow and enhanced melt rates in a warmer climate fuelled the debate regarding the temporal and spatial controls on seasonal ice acceleration. Here we combine melt, basal water pressure and ice velocity data. Using 20 years of data covering the whole ablation area, we show that there is not a strong positive correlation between annual ice velocities and melt rates. Annual velocities even slightly decreased with increasing melt. Results also indicate that melt variations are most important for velocity variations in the upper ablation zone up to the equilibrium line altitude. During the extreme melt in 2012, a large velocity response near the equilibrium line was observed, highlighting the possibility of meltwater to have an impact even high on the ice sheet. This may lead to an increase of the annual ice velocity in the region above S9 and requires further monitoring.

  5. High-resolution, terrestrial radar velocity observations and model results reveal a strong bed at stable, tidewater Rink Isbræ, West Greenland

    Science.gov (United States)

    Bartholomaus, T. C.; Walker, R. T.; Stearns, L. A.; Fahnestock, M. A.; Cassotto, R.; Catania, G. A.; Felikson, D.; Fried, M.; Sutherland, D.; Nash, J. D.; Shroyer, E.

    2015-12-01

    At tidewater Rink Isbræ, on the central west coast of Greenland, satellite observations reveal that glacier velocities and terminus positions have remained stable, while the lowest 25 km have thinned 30 m since 1985. Over this same time period, other tidewater glaciers in central west Greenland have retreated, thinned and accelerated. Here we present field observations and model results to show that the flow of Rink Isbræ is resisted by unusually high basal shear stresses. Terrestrial radar interferometry (TRI) observations over 9 days in summer 2014 demonstrate weak velocity response to 4 km wide, full thickness calving events. Velocities at the terminus change by +/- 10% in response to rising and falling tides within a partial-width, 2.5-km-long floating ice tongue; however these tidal perturbations damp out within 2 km of the grounding line. Inversions for basal shear stress and force balance analyses together show that basal shear stresses in excess of 300 kPa support the majority of the driving stress at thick, steep Rink Isbræ. These observational and modeling results tell a consistent story in which a strong bed may limit the unstable tidewater glacier retreats observed elsewhere. Rink Isbræ has an erosion resistant quartzite bed with low fracture density. We hypothesize that this geology may play a major role in the bed strength.

  6. Plate Tectonics at 3.8-3.7 Ga: Field Evidence from the Isua Accretionary Complex, Southern West Greenland.

    Science.gov (United States)

    Komiya; Maruyama; Masuda; Nohda; Hayashi; Okamoto

    1999-09-01

    A 1&rcolon;5000 scale mapping was performed in the Isukasia area of the ca. 3.8-Ga Isua supracrustal belt, southern West Greenland. The mapped area is divided into three units bounded by low-angle thrusts: the Northern, Middle, and Southern Units. The Southern Unit, the best exposed, is composed of 14 subunits (horses) with similar lithostratigraphy, bound by layer-parallel thrusts. Duplex structures are widespread in the Isua belt and vary in scale from a few meters to kilometers. Duplexing proceeded from south to north and is well documented in the relationship between link- and roof-thrusts. The reconstructed lithostratigraphy of each horse reveals a simple pattern, in ascending order, of greenstone with low-K tholeiitic composition with or without pillow lava structures, chert/banded iron-formation, and turbidites. The cherts and underlying low-K tholeiites do not contain continent- or arc-derived material. The lithostratigraphy is quite similar to Phanerozoic "oceanic plate stratigraphy," except for the abundance of mafic material in the turbidites. The evidence of duplex structures and oceanic plate stratigraphy indicates that the Isua supracrustal belt is the oldest accretionary complex in the world. The dominantly mafic turbidite composition suggests that the accretionary complex was formed in an intraoceanic environment comparable to the present-day western Pacific Ocean. The duplex polarity suggests that an older accretionary complex should occur to the south of the Isua complex. Moreover, the presence of seawater (documented by a thick, pillow, lava unit at the bottom of oceanic plate stratigraphy) indicates that the surface temperature was less than ca. 100 degrees C in the Early Archean. The oceanic geotherm for the Early Archean lithosphere as a function of age was calculated based on a model of transient half-space cooling at given parameters of surface and mantle temperatures of 100 degrees and 1450 degrees C, respectively, suggesting that the

  7. Geochemical Evidence for Subduction in the Early Archaean from Quartz-Carbonate-Fuchsite Mineralization, Isua Supracrustal Belt, West Greenland

    Science.gov (United States)

    Pope, E. C.; Rosing, M. T.; Bird, D. K.

    2011-12-01

    Quartz, carbonate and fuchsite (chromian muscovite) is a common metasomatic assemblage observed in orogenic gold systems, both in Phanerozoic convergent margin settings, and within supracrustal and greenstone belts of Precambrian rocks. Geologic and geochemical observations in younger orogenic systems suggest that ore-forming metasomatic fluids are derived from subduction-related devolitilization reactions, implying that orogenic Au-deposits in Archaean and Proterozoic supracrustal rock suites are related to subduction-style plate tectonics beginning early in Earth history. Justification of this metasomatic-tectonic relationship requires that 1) Phanerozoic orogenic Au-deposits form in subduction-zone environments, and 2) the geochemical similarity of Precambrian orogenic deposits to their younger counterparts is the result of having the same petro-genetic origin. Hydrogen and oxygen isotope compositions of fuchsite and quartz from auriferous mineralization in the ca. 3.8 Ga Isua Supracrustal Belt (ISB) in West Greenland, in conjunction with elevated concentrations of CO2, Cr, Al, K and silica relative to protolith assemblages, suggest that this mineralization shares a common petro-tectonic origin with Phanerozoic orogenic deposits and that this type of metasomatism is a unique result of subduction-related processes. Fuchsite from the ISB has a δ18O and δD of +7.7 to +17.9% and -115 to -61%, respectively. δ18O of quartz from the same rocks is between +10.3 and +18.6%. Muscovite-quartz oxygen isotope thermometry indicates that the mineralization occurred at 560 ± 90oC, from fluids with a δD of -73 to -49% and δ18O of +8.8 to +17.2%. Calculation of isotopic fractionation during fluid-rock reactions along hypothetical fluid pathways demonstrates that these values, as well as those in younger orogenic deposits, are the result of seawater-derived fluids liberated from subducting lithosphere interacting with ultramafic rocks in the mantle wedge and lower crust

  8. A cascade of warming impacts brings bluefin tuna to Greenland waters

    DEFF Research Database (Denmark)

    MacKenzie, Brian R.; Payne, Mark R.; Boje, Jesper;

    2014-01-01

    for Atlantic mackerel, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9-11 °C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed...... to a warming trend since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species to the region. We conclude that a cascade of climate change...... impacts is restructuring the food web in east Greenland waters....

  9. Ice-water vortex at the edge of the East Greenland current

    Energy Technology Data Exchange (ETDEWEB)

    Wadhams, P.; Squire, V.A.

    1983-03-30

    During the Ymer-80 cruise in August 1980 we observed an ice feature of 60-km diameter having the shape of a breaking wave. It lay at the edge of the East Greenland drift ice in Fram Strait with its center at 79/sup 0/15'N, 00/sup 0/38'E, and the wave was breaking upstream relative to the East Greenland current. Two conductivity, temperature, and depth sections across the feature in N-S and E-W directions revealed warm (up to 4.3 C) water some 60 km inside the polar front, in lenses centered at 40-m depth but with an effect to beyond 600 m. The temperature anomalies were accompanied by salinity anomalies so that there was little net effect on the density profile. The form of the sections, together with the ice distribution (observed by vertical photography from a helicopter) and surface motion (observed by tracking four radar transponders) all suggest that the feature is a vortex produced by an instability in the polar front. It has similar characteristics to vortices investigated experimentally and theoretically by Griffiths and Linden (1981a, b, 1982) and observationally by Wadhams et al. (1979).

  10. An ice-water vortex at the edge of the East Greenland Current

    Science.gov (United States)

    Wadhams, P.; Squire, V. A.

    1983-03-01

    During the Y mer-80 cruise in August 1980 we observed an ice feature of 60-km diameter having the shape of a breaking wave. It lay at the edge of the East Greenland drift ice in Fram Strait with its center at 79°15'N, 00°38'E, and the wave was breaking upstream relative to the East Greenland Current. Two conductivity, temperature, and depth sections across the feature in N-S and E-W directions revealed warm (up to 4.3°C) water some 60 km inside the polar front, in lenses centered at 40-m depth but with an effect to beyond 600 m. The temperature anomalies were accompanied by salinity anomalies so that there was little net effect on the density profile. The form of the sections, together with the ice distribution (observed by vertical photography from a helicopter) and surface motion (observed by tracking four radar transponders) all suggest that the feature is a vortex produced by an instability in the polar front. It has similar characteristics to vortices investigated experimentally and theoretically by Griffiths and Linden (1981a, b, 1982) and observationally by Wadhams et al. (1979).

  11. The distribution of artificial radionuclides in the waters of the Norwegian-Greenland Sea in 1985

    Energy Technology Data Exchange (ETDEWEB)

    Wedekind, C.; Gabriel, H.; Goroncy, I.; Framcke, G. [Bundesamt fuer Seeschiffahrt und Hydrographie, Hamburg (Germany)

    1997-07-01

    In the summer of 1985, sea water samples were taken to determine {sup 3}H, {sup 90}Sr, {sup 134}Cs, {sup 137}Cs and transuranics within a grid of 165 stations including 16 depth series down to the seafloor, covering all ice-free areas. The distribution of the activity concentrations and the nuclide ratios reveal the contamination pathway into the surface and deeper layers of the Norwegian-Greenland Sea from nuclear weapon fallout and civil nuclear technology. Moreover, the investigations show that: (1) a yearly discharge of 1 TBq (10{sup 12} Bq) {sup 90}Sr into the Irish Sea (English Channel) is diluted on its way to the southern Norwegian Sea, raising the concentration by about 0.04 m Bql{sup -1}; (2) the drift time to this sea area is around 4 years; (3) about 40% of the {sup 137}Cs discharged does not reach the Norwegian Sea and (4) a further 30% leaves the Norwegian-Greenland Sea via the North Cape and flows into the Barents Sea. Investigations into the vertical distribution and stratification of the radioactivity indicate the time scale on which the radionuclides travel to the deeper layers. (author).

  12. Oxygen and carbon isotope composition of Quaternary bivalve shells as a water mass indicator: Last interglacial and Holocene, East Greenland

    DEFF Research Database (Denmark)

    Israelson, C.; Buchardt, Bjørn; Funder, S.V.

    1994-01-01

    to south along the Ea5t Greenland coast \\\\as also present during the Holaccnc dimatil.: optimum 800n -7{JOO yr B.P. Analyses of b;\\'al\\t: shells from the last interglacial sho\\\\! that Scoresby Sund during that time was weB circulated and that mell\\\\Jter from 1h.... Greenland ice sheet and sea ice meltwater......Oxygen and carhon isotope composition of arctic bivahe shells are used in an attempt to reCO'1struct -.urface water temperature and salinities in Scoresby Sund. East Greenland. The oxygen i:;otope compositions or .1,tw mllicuf£!. Hialclla arctica and Tridmlla hOl'm!is han~ been compared...

  13. Colonization history and clonal richness of asexual Daphnia in periglacial habitats of contrasting age in West Greenland.

    Science.gov (United States)

    Haileselasie, Tsegazeabe H; Mergeay, Joachim; Weider, Lawrence J; Jeppesen, Erik; De Meester, Luc

    2016-07-01

    Due to climate change, Arctic ice sheets are retreating. This leads to the formation of numerous new periglacial ponds and lakes, which are being colonized by planktonic organisms such as the water flea Daphnia. This system provides unique opportunities to test genotype colonization dynamics and the genetic assemblage of populations. Here, we studied clonal richness of the Daphnia pulex species complex in novel periglacial habitats created by glacial retreat in the Jakobshavn Isbrae area of western Greenland. Along a 10 km transect, we surveyed 73 periglacial habitats out of which 61 were colonized by Daphnia pulex. Hence, for our analysis, we used 21 ponds and 40 lakes in two clusters of habitats differing in age (estimated 150 years). We tested the expectation that genetic diversity would be low in recently formed (i.e. young), small habitats, but would increase with increasing age and size. We identified a total of 42 genetically distinct clones belonging to two obligately asexual species of the D. pulex species complex: D. middendorffiana and the much more abundant D. pulicaria. While regional clonal richness was high, most clones were rare: 16 clones were restricted to a single habitat and the five most widespread clones accounted for 68% of all individuals sampled. On average, 3·2 clones (range: 1-12) coexisted in a given pond or lake. There was no relationship between clonal richness and habitat size when we controlled for habitat age. Whereas clonal richness was statistically higher in the cluster of older habitats when compared with the cluster of younger ponds and lakes, most young habitats were colonized by multiple genotypes. Our data suggest that newly formed (periglacial) ponds and lakes are colonized within decades by multiple genotypes via multiple colonization events, even in the smallest of our study systems (4 m(2) ).

  14. Subglacial water drainage, storage, and piracy beneath the Greenland ice sheet

    Science.gov (United States)

    Lindbäck, K.; Pettersson, R.; Hubbard, A. L.; Doyle, S. H.; As, D.; Mikkelsen, A. B.; Fitzpatrick, A. A.

    2015-09-01

    Meltwater drainage across the surface of the Greenland ice sheet (GrIS) is well constrained by measurements and modeling, yet despite its critical role, knowledge of its transit through the subglacial environment remains limited. Here we present a subglacial hydrological analysis of a land-terminating sector of the GrIS at unprecedented resolution that predicts the routing of surface-derived meltwater once it has entered the basal drainage system. Our analysis indicates the probable existence of small subglacial lakes that remain undetectable by methods using surface elevation change or radar techniques. Furthermore, the analysis suggests transient behavior with rapid switching of subglacial drainage between competing catchments driven by seasonal changes in the basal water pressure. Our findings provide a cautionary note that should be considered in studies that attempt to relate and infer future response from surface temperature, melt, and runoff from point measurements and/or modeling with measurements of proglacial discharge and ice dynamics.

  15. Wintertime storage of water in buried supraglacial lakes across the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    L. S. Koenig

    2014-07-01

    Full Text Available Surface melt over the Greenland Ice Sheet (GrIS is increasing and estimated to account for half or more of the total mass loss. Little, however, is known about the hydrologic pathways that route surface melt within the ice sheet. In this study, we present over-winter storage of water in buried supraglacial lakes as one hydrologic pathway for surface melt, referred to as buried lakes. Airborne radar echograms are used to detect the buried lakes that are distributed extensively around the margin of the GrIS. The subsurface water can persist through multiple winters and is, on average, ~4.2 + 0.4 m below the surface. The few buried lakes that are visible at the surface of the GrIS have a~unique visible signature associated with a darker blue color where subsurface water is located. The volume of retained water in the buried lakes is likely insignificant compared to the total mass loss from the GrIS but the water will have important implications locally for the development of the englacial hydrologic network, ice temperature profiles and glacial dynamics. The buried lakes represent a small but year-round source of meltwater in the GrIS hydrologic system.

  16. Are seasonal calving dynamics forced by buttressing from ice mélange or undercutting by melting? Outcomes from full-Stokes simulations of Store Gletscher, West Greenland

    Directory of Open Access Journals (Sweden)

    J. Todd

    2014-07-01

    Full Text Available We use a full-Stokes 2-D model (Elmer/Ice to investigate the flow and calving dynamics of Store Gletscher, a fast flowing outlet glacier in West Greenland. Based on a new, subgrid-scale implementation of the crevasse depth calving criterion, we perform two sets of simulations; one to identify the primary forcing mechanisms and another to constrain future stability. We find that the mixture of icebergs and sea-ice, known as ice mélange or sikussak, is principally responsible for the observed seasonal advance of the ice front, whereas submarine melting plays a secondary role. Sensitivity analysis demonstrates that the glacier's calving dynamics are sensitive to seasonal perturbation, but are stable on interannual timescales due to the glacier's topographic setting. Our results shed light on the dynamics of calving glaciers while explaining why neighbouring glaciers do not necessarily respond synchronously to changes in atmospheric and oceanic forcing.

  17. Strontium and neodymium isotopic variations in early Archean gneisses affected by middle to late Archean high-grade metamorphic processes: West Greenland and Labrador

    Science.gov (United States)

    Collerson, K. D.; Mcculloch, M. T.; Bridgwater, D.; Mcgregor, V. R.; Nutman, A. P.

    1986-01-01

    Relicts of continental crust formed more than 3400 Ma ago are preserved fortuitously in most cratons. The cratons provide the most direct information about crust and mantle evolutionary processes during the first billion years of Earth history. In view of their polymetamorphic character, these terrains are commonly affected by subsequent tectonothermal events. Hence, their isotope systematics may be severely disturbed as a result of bulk chemical change or local isotopic homogenization. This leads to equivocal age and source information for different components within these terrains. The Sr and Nd isotopic data are presented for early Archean gneisses from the North Atlantic Craton in west Greenland and northern Labrador which were affected by younger metamorphic events.

  18. A preliminary strategic environmental impact assessment of mineral and hydrocarbon activities on the Nuussuaq peninsula, West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Boertmann, D.; Asmund, G.; Glahder, C.; Tamstorf, M.

    2008-01-15

    There is an increasing interest for mineral and hydrocarbon exploration in Greenland and in both regards the Nuussuaq peninsula is in focus. This preliminary strategic environmental impact assessment describes the status of the biological knowledge from the area and designates potential conflicts between activities and the biological environment. Furthermore biological knowledge gaps are identified. These should be filled before specific environmental impacts assessments can be carried out and relevant studies to fill these data gaps are proposed. (au)

  19. Widespread Refreezing of Both Surface and Basal Melt Water Beneath the Greenland Ice Sheet

    Science.gov (United States)

    Bell, R. E.; Tinto, K. J.; Das, I.; Wolovick, M.; Chu, W.; Creyts, T. T.; Frearson, N.

    2013-12-01

    The isotopically and chemically distinct, bubble-free ice observed along the Greenland Ice Sheet margin both in the Russell Glacier and north of Jacobshavn must have formed when water froze from subglacial networks. Where this refreezing occurs and what impact it has on ice sheet processes remain unclear. We use airborne radar data to demonstrate that freeze-on to the ice sheet base and associated deformation produce large ice units up to 700 m thick throughout northern Greenland. Along the ice sheet margin, in the ablation zone, surface meltwater, delivered via moulins, refreezes to the ice sheet base over rugged topography. In the interior, water melted from the ice sheet base is refrozen and surrounded by folded ice. A significant fraction of the ice sheet is modified by basal freeze-on and associated deformation. For the Eqip and Petermann catchments, representing the ice sheet margin and interior respectively, extensive airborne radar datasets show that 10%-13% of the base of the ice sheet and up to a third of the catchment width is modified by basal freeze-on. The interior units develop over relatively subdued topography with modest water flux from basal melt where conductive cooling likely dominates. Steps in the bed topography associated with subglacial valley networks may foster glaciohydraulic supercooling. The ablation zone units develop where both surface melt and crevassing are widespread and large volumes of surface meltwater will reach the base of the ice sheet. The relatively steep topography at the upslope edge of the ablation zone units combined with the larger water flux suggests that supercooling plays a greater role in their formation. The ice qualities of the ablation zone units should reflect the relatively fresh surface melt whereas the chemistry of the interior units should reflect solute-rich basal melt. Changes in basal conditions such as the presence of till patches may contribute to the formation of the large basal units near the

  20. Water mass characteristics and associated fauna of a recently discovered Lophelia pertusa (Scleractinia: Anthozoa) reef in Greenlandic waters

    DEFF Research Database (Denmark)

    Kenchington, Ellen; Yashayaev, Igor; Tendal, Ole Secher

    2017-01-01

    , and in an area with exceptionally and persistently high currents of >15 cm s−1 at 1000 m. The intermediate-depth salinity maximum was found in the depth range where the corals were found. We discovered signals of consistent vertical and horizontal transports at 700–900 m over the reef area. Although this area......The first living sample of Lophelia pertusa from Greenlandic waters was inadvertently collected at 60.3675°, −48.45528°, entangled together with other corals to a seawater sampler and property sensor (CTD) package. We collected in situ photographs taken at two sites in the same area in order...... to determine whether a reef was present. We identified reef-like structures formed by living and dead L. pertusa at 886–932 m depth on a steep slope. We assembled and analyzed hydrographic data to characterize the reef environment in order to facilitate future localization of other reefs and predictions...

  1. Possible Greenland

    DEFF Research Database (Denmark)

    2012-01-01

    Organizing in Greenland is a complex matter. We have been on an arctic odyssey exploring the different aspects of the Greenlandic reality and have created a publication in which a wide range of Greenlandic and international profiles and stakeholders give their opinion and visions for the future...... development in Greenland. By creating a platform for a wide range of ideas about the Possible Greenland to be discussed now and in the future, we give Greenlanders and Greenlandic decision makers access to the greatest amount of possible solutions to the challenges they are facing. We look more closely...... at Greenland's structure, and ask some threshold questions. Which aspects of society are rooted in our human hardware? And, if we had the rare opportunity to build a new nation, what would we choose for ourselves? We hope this will inspire an open, imaginative and thoroughly human discussion about how...

  2. Late-Holocene environment and climatic changes in Ameralik Fjord, southwest Greenland: evidence from the sedimentary record

    DEFF Research Database (Denmark)

    Møller, Henrik S.; Jensen, Karin G.; Kuijpers, Antoon

    2006-01-01

    of fine (silty) sediments related to strong melt-water discharge from the Inland Ice. The benthic foraminiferal fauna demonstrates the presence of well-ventilated, saline bottom water originating from inflow of subsurface West Greenland Current water of Atlantic (Irminger Sea) origin. The hydrographic......  Sedimentological and geochemical (XRF) data together with information from diatom and benthic foraminifera records of a 3.5 m long gravity core from Ameralik fjord, southern West Greenland, is used for reconstructing late Holocene environmental changes in this area. The changes are linked...... with a decreased meltwater discharge and more widespread sea-ice cover in the fjord....

  3. Envisioning Greenland

    DEFF Research Database (Denmark)

    Ren, Carina Bregnholm

    2012-01-01

    Currently, the traditional ‘cool’ representation of Greenland as a frozen landscape devoid of people and human structures is being challenged by an emerging vision of Greenland as ‘hot’. This article presents and describes these two versions of Greenland, showing how demarcations of what is ‘nature...

  4. Possible Greenland

    DEFF Research Database (Denmark)

    2012-01-01

    Organizing in Greenland is a complex matter. We have been on an arctic odyssey exploring the different aspects of the Greenlandic reality and have created a publication in which a wide range of Greenlandic and international profiles and stakeholders give their opinion and visions for the future d...

  5. Drainage of Southeast Greenland firn aquifer water through crevasses to the bed

    Science.gov (United States)

    Poinar, Kristin; Joughin, Ian; Lilien, David; Brucker, Ludovic; Kehrl, Laura; Nowicki, Sophie

    2017-02-01

    A firn aquifer in the Helheim Glacier catchment of Southeast Greenland lies directly upstream of a crevasse field. Previous measurements show that a 3.5-km long segment of the aquifer lost a large volume of water (26,000 - 65,000 m2 in cross section) between spring 2012 and spring 2013, compared to annual meltwater accumulation of 6000 - 15,000 m2. The water is thought to have entered the crevasses, but whether the water reached the bed or refroze within the ice sheet is unknown. We used a thermo-visco-elastic model for crevasse propagation to calculate the depths and volumes of these water-filled crevasses. We compared our model output to data from the Airborne Topographic Mapper (ATM), which reveals the near-surface geometry of specific crevasses, and WorldView images, which capture the surface expressions of crevasses across our 1.5-km study area. We found a best fit with a shear modulus between 0.2 and 1.5 GPa within our study area. We show that surface meltwater can drive crevasses to the top surface of the firn aquifer ( 20 m depth), whereupon it receives water at rates corresponding to the water flux through the aquifer. Our model shows that crevasses receiving firn-aquifer water hydrofracture through to the bed, 1000 m below, in 10-40 days. Englacial refreezing of firn-aquifer water raises the average local ice temperature by 4°C over a ten-year period, which enhances deformational ice motion by 50 m/yr, compared to the observed surface velocity of 200 m/yr. The effect of the basal water on the sliding velocity remains unknown. Were the firn aquifer not present to concentrate surface meltwater into crevasses, we find that no surface melt would reach the bed; instead, it would refreeze annually in crevasses at depths ice-sheet dynamics by routing a large volume of water to the bed outside of the typical runoff period.

  6. Suspended Matter, Chl-a, CDOM, Grain Sizes, and Optical Properties in the Arctic Fjord-Type Estuary, Kangerlussuaq, West Greenland During Summer

    DEFF Research Database (Denmark)

    Lund-Hansen, L. C.; Andersen, T. J.; Nielsen, Morten Holtegaard

    2010-01-01

    attenuation coefficient of downwelling PAR (K (d)(PAR)), upwelling PAR (K (u)(PAR)), particle beam attenuation coefficient (c (p)), and irradiance reflectance R(-0, PAR). PAR is white light between 400 and 700 nm. The estuary receives melt water from the Greenland Inland Ice and stations covered a transect......Optical constituents as suspended particulate matter (SPM), chlorophyll (Chl-a), colored dissolved organic matter (CDOM), and grain sizes were obtained on a transect in the arctic fjord-type estuary Kangerlussuaq (66A degrees) in August 2007 along with optical properties. These comprised diffuse...... from the very high turbid melt water outlet to clear marine waters. Results showed a strong spatial variation with high values as for suspended matter concentrations, CDOM, diffuse attenuation coefficient K (d)(PAR), particle beam attenuation coefficients (c (p)), and reflectance R(-0, PAR) at the melt...

  7. The optical properties of greenlandic coastal waters: Modelling light penetration in a changing climate

    DEFF Research Database (Denmark)

    Stedmon, Colin; Markager, S.S.; Pedersen, T.J.

    Greenlandic fjords are very productive and pristine ecosystems, which the local population is both intrinsically linked to and dependent on through heritage, industrial fisheries, and tourism. The availability and spectral quality of light are key parameters controlling the productivity...

  8. Self-affine subglacial roughness: consequences for radar scattering and basal water discrimination in northern Greenland

    Science.gov (United States)

    Jordan, Thomas M.; Cooper, Michael A.; Schroeder, Dustin M.; Williams, Christopher N.; Paden, John D.; Siegert, Martin J.; Bamber, Jonathan L.

    2017-05-01

    Subglacial roughness can be determined at a variety of length scales from radio-echo sounding (RES) data either via statistical analysis of topography or inferred from basal radar scattering. Past studies have demonstrated that subglacial terrain exhibits self-affine (power law) roughness scaling behaviour, but existing radar scattering models do not take this into account. Here, using RES data from northern Greenland, we introduce a self-affine statistical framework that enables a consistent integration of topographic-scale roughness with the electromagnetic theory of radar scattering. We demonstrate that the degree of radar scattering, quantified using the waveform abruptness (pulse peakiness), is topographically controlled by the Hurst (roughness power law) exponent. Notably, specular bed reflections are associated with a lower Hurst exponent, with diffuse scattering associated with a higher Hurst exponent. Abrupt waveforms (specular reflections) have previously been used as a RES diagnostic for basal water, and to test this assumption we compare our radar scattering map with a recent prediction for the basal thermal state. We demonstrate that the majority of thawed regions (above pressure melting point) exhibit a diffuse scattering signature, which is in contradiction to the prior approach. Self-affine statistics provide a generalised model for subglacial terrain and can improve our understanding of the relationship between basal properties and ice-sheet dynamics.

  9. Holocene paleotemperature signals based on polar firn water isotope diffusion studies from two Greenland ice cores.

    Science.gov (United States)

    Gkinis, Vasileios; Terkelsen Holme, Christian; Møllesøe Vinther, Bo

    2017-04-01

    Polar ice cores provide a wealth of paleoclimatic information that is characterised by high temporal resolution and continuity, with water isotopic ratios of polar precipitation (δ18O, δD) being one of the most prominent proxies for past temperatures. In particular, ice cores from Greenland, record the series of abrupt stadial - interstadial transitions during the last Glacial, pinpointing in time, abrupt temperature transitions adjoined by similar accumulation trends. While the signal to noise ratio of the isotopic signal clearly allows the observation of sizable climate changes during the Glacial, the situation differs considerably when one looks into the Holocene. With the exception of the 8.2ky event, the signal to noise ratio of δ18O over the Holocene is extremely low, suggesting negligible temperature changes during this period. This is contrary to signals obtained by other proxies from marine and terrestrial records from high latitudes. In this study we bypass the discussion that deals with the various processes that can negatively affect paleotemperature reconstructions based on the δ18O proxy from ice cores. Based on two ultra-high resolution and high precision isotopic records covering the last 20,000 years from the NorthGRIP and NEEM ice cores we make use of the available spectral information to infer polar firn paleotemperatures using a coupled densification - firn water isotope diffusion model. The processes involved in the densification of firn and the diffusion of water isotopes that takes place after deposition and until the pore close-off are temperature-dependent and do not present the limitations of the normal δ18O thermometer. We show here how this approach reveals significant temperature changes over the Holocene. We compare the signals of the two records and pay particular attention to the indications of a mid-Holocene climatic shift towards colder temperatures that is apparent in both temperature reconstructions.

  10. Water resources of West Baton Rouge Parish, Louisiana

    Science.gov (United States)

    White, Vincent E.; Prakken, Lawrence B.

    2016-11-23

    Information concerning the availability, use, and quality of water in West Baton Rouge Parish, Louisiana, is critical for proper water-resource management. The purpose of this fact sheet is to present information that can be used by water managers, parish residents, and others for stewardship of this vital resource. Information on the availability, past and current use, use trends, and water quality from groundwater and surface-water sources in the parish is presented. Previously published reports and data stored in the U.S. Geological Survey’s National Water Information System (http://waterdata.usgs.gov/nwis) are the primary sources of the information presented here.

  11. A review of structural patterns and melting processes in the Archean craton of West Greenland: Evidence for crustal growth at convergent plate margins as opposed to non-uniformitarian models

    Science.gov (United States)

    Polat, Ali; Wang, Lu; Appel, Peter W. U.

    2015-11-01

    The Archean craton of West Greenland consists of many fault-bounded Eoarchean to Neoarchean tectonic terranes (crustal blocks). These tectonic terranes are composed mainly of tonalite-trondhjemite-granodiorite (TTG) gneisses, granitic gneisses, metavolcanic-dominated supracrustal belts, layered anorthositic complexes, and late- to post-tectonic granites. Rock assemblages and geochemical signatures in these terranes suggest that they represent fragments of dismembered oceanic island arcs, consisting mainly of TTG plutons, tholeiitic to calc-alkaline basalts, boninites, picrites, and cumulate layers of ultramafic rocks, gabbros, leucogabbros and anorthosites, with minor sedimentary rocks. The structural characteristics of the terrane boundaries are consistent with the assembly of these island arcs through modern style of horizontal tectonics, suggesting that the Archean craton of West Greenland grew at convergent plate margins. Several supracrustal belts that occur at or near the terrane boundaries are interpreted as relict accretionary prisms. The terranes display fold and thrust structures and contain numerous 10 cm to 20 m wide bifurcating, ductile shear zones that are characterized by a variety of structures including transposed and redistributed isoclinal folds. Geometrically these structures are similar to those occurring on regional scales, suggesting that the Archean craton of West Greenland can be interpreted as a continental scale accretionary complex, such as the Paleozoic Altaids. Melting of metavolcanic rocks during tectonic thickening in the arcs played an important role in the generation of TTGs. Non-uniformitarian models proposed for the origin of Archean terranes have no analogs in the geologic record and are inconsistent with structural, lithological, petrological and geochemical data collected from Archean terranes over the last four decades. The style of deformation and generation of felsic rocks on outcrop scales in the Archean craton of West

  12. Additions to the family Miroviaceae (Coniferae) from the Lower Cretaceous of West Greenland and Germany: Mirovia groenlandica n. sp., Tritaenia crassa (Seward) comb, nov., and Tritaenia linkii Magdefrau et Rudolph emend.

    OpenAIRE

    N. Bose, Mahendra; Manum, Svein B.

    1991-01-01

    The genus Tritaenia with its type species T. linkii Magdefrau et Rudolph emend, from the Wealden of Germany has been referred to the family Miroviaceae Bose et Manum, comprising Mesozoic and mostly Arctic conifer foliage with ‘Sciadopitys-like’ stomatal distribution. Two other additions to the Miroviaceae, both from the Lower Cretaceous of West Greenland, arc Pityophyllum crassum Seward, now attributed to Tritaenia, and Mirovia groenlandica n. sp., described on leafy stems and detached leaves...

  13. The Greenland shark

    DEFF Research Database (Denmark)

    Costantini, David; Smith, Shona; Killen, Shaun S.;

    2017-01-01

    the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase...... that the values of metrics of oxidative status we measured might be linked to ecological features (e.g., adaptation to cold waters and deep dives) of this shark species rather to its lifespan....

  14. Early life of inshore fishes in Greenland

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus

    regimes, relative inflowof Atlantic water, temperature increase, glacial melting and runoff from land, the environment off West Greenland will undergo significant changes in the future. This thesis points out that in fjord systems, where such processes might change the timing and magnitude of freshwater....... The distribution of larvae generally overlapped the distribution of their preferred prey. Although no direct relationship could be found between prey availability and cod larval growth, the otolith growth rate was significantly improved in larvae that dispersing away from the spawning area. This was despite lower...... Greenlandic Godthåbsfjord system and the offshore Fyllas Bank, which encompass different oceanographic regimes, and which harbor different zooplanktoncommunities in specific regions. Significantly different patterns of distribution were shown for the fish larvae and these appeared linked to the specific...

  15. Investigating the Spatial and Temporal Variability of Water Saturation Within the Greenland Firn Aquifer Using Ground Penetrating Radar

    Science.gov (United States)

    Brautigam, N.

    2015-12-01

    Ground Penetrating Radar (GPR) is used to investigate the spatial and temporal saturation of the Greenland firn aquifer, using a method recently developed on a Svalbard icesheet (Christianson et. al., 2015). Currently, saturation of the firn is assumed to be 100% (Koenig et. al., 2014; Forster et. al., 2014), and using a firn density correction this saturation level drives the present liquid water volume estimate (140±20 Gt) of the Greenland firn aquifer (Koenig et. al., 2014). Based on earlier studies on mountain glacier firn aquifers, we suspect that saturation levels vary with depth, annual precipitation patterns, and local topography (Fountain, 1989; Christianson et. al., 2015). Refining the liquid water volume estimation is an important parameter as it allows for a better determination of the amount of water potentially available for release and consequent sea level rise, as well as to better model glacial processes such as englacial flow, crevasse fracture, and basal lubrication. GPR and GPS data collected along a 2.6 km transect in 2011, 2013, and 2014 in southeastern Greenland is used to measure the spatial and temporal variability of saturation levels within the aquifer. A bright reflector seen in the GPR at the water table depth responds to local topography. At surface lows, the reflector rises, intersecting annual density change layers visible in the GPR data. At these intersections, the annual layers deflect down beneath the water table before being lost due to signal attenuation. We assume that this deflection is due to a change in dielectric permittivity, and that by measuring the angle of deflection, and implementing a mixing model and density correction from nearby firn cores, we can determine the saturation level at each point along a deflection. This allows us to investigate the spatial and temporal variability of saturation within the firn aquifer.

  16. First Younger Dryas moraines in Greenland

    Science.gov (United States)

    Funder, Svend; Larsen, Nicolaj K.; Linge, Henriette; Möller, Per; Schomacker, Anders; Fabel, Derek; Kjær, Kurt H.; Xu, Sheng

    2016-04-01

    general was characterised by large scale, more than 200 km, retreat on the shelf. Therefore, although readvance and retreat occurred in both areas, the readvance was apparently not triggered by the initial YD cooling nor was the retreat caused by the abrupt warming at the end. At all other sites with a record that run through or into YD - Southeast Greenland, South Greenland, northern West Greenland - the ice margins were apparently retreating through YD, leaving the north coast as the only area with evidence for a climatically conditioned YD readvance/retreat. The apparent mismatch between ice core temperatures and ice margin behaviour is generally seen as a function of reduced AMOC (Atlantic Meridional Overturning Circulation), inducing both higher seasonality with very cold winters and warm summers, and also occurrence of warm subsurface water to melt the ice sheet margin along some coasts. Therefore the ice margin response to the cold oscillation was to some extent determined by the nearness to the North Atlantic - with North Greenland being the farthest away. Although this may explain why glaciers advanced in North Greenland, while they melted in more southerly parts, it still leaves the question with a bearing on the future: why don't we see any ice margin response neither to the initial YD cooling, nor to the abrupt warming at the end?

  17. The Shallow-water Octocorallia of the West Indian Region

    NARCIS (Netherlands)

    Bayer, Frederick M.

    1961-01-01

    The alcyonarian fauna of the West Indies is prolific and conspicuous and has been known for many years, with the natural result that a great many more species have been described than actually exist. The deep-water fauna, which received little attention prior to the work of VERRILL, was thoroughly r

  18. The Shallow-water Octocorallia of the West Indian Region

    NARCIS (Netherlands)

    Bayer, Frederick M.

    1961-01-01

    The alcyonarian fauna of the West Indies is prolific and conspicuous and has been known for many years, with the natural result that a great many more species have been described than actually exist. The deep-water fauna, which received little attention prior to the work of VERRILL, was thoroughly

  19. Pb isotopes as tracers of mining-related Pb in lichens, seaweed and mussels near a former Pb-Zn mine in West Greenland

    DEFF Research Database (Denmark)

    Søndergaard, Jens; Asmund, Gert; Johansen, Poul

    2010-01-01

    Identification of mining-related contaminants is important in order to assess the spreading of contaminants from mining as well as for site remediation purposes. This study focuses on lead (Pb) contamination in biota near the abandoned ‘Black Angel Mine’ in West Greenland in the period 1988......–2008. Stable Pb isotope ratios and total Pb concentrations were determined in lichens, seaweed and mussels as well as in marine sediments. The results show that natural background Pb (207Pb/206Pb: 0.704–0.767) and Pb originating from the mine ore (207Pb/206Pb: 0.955) have distinct isotopic fingerprints. Total...... Pb in lichens, seaweed, and mussels was measured at values up to 633, 19 and 1536 mg kg-1 dry weight, respectively, and is shown to be a mixture of natural Pb and ore-Pb. This enables quantification of mining-related Pb and shows that application of Pb isotope data is a valuable tool for monitoring...

  20. Are seasonal calving dynamics forced by buttressing from ice mélange or undercutting by melting? Outcomes from full-Stokes simulations of Store Glacier, West Greenland

    Science.gov (United States)

    Todd, J.; Christoffersen, P.

    2014-12-01

    We use a full-Stokes 2-D model (Elmer/Ice) to investigate the flow and calving dynamics of Store Glacier, a fast-flowing outlet glacier in West Greenland. Based on a new, subgrid-scale implementation of the crevasse depth calving criterion, we perform two sets of simulations: one to identify the primary forcing mechanisms and another to constrain future stability. We find that the mixture of icebergs and sea ice, known as ice mélange or sikussak, is principally responsible for the observed seasonal advance of the ice front. On the other hand, the effect of submarine melting on the calving rate of Store Glacier appears to be limited. Sensitivity analysis demonstrates that the glacier's calving dynamics are sensitive to seasonal perturbation, but are stable on interannual timescales due to the strong topographic control on the flow regime. Our results shed light on the dynamics of calving glaciers and may help explain why neighbouring glaciers do not necessarily respond synchronously to changes in atmospheric and oceanic forcing.

  1. Microwave measurements of temperature profiles, integrated water vapour, and liquid water path at Thule Air Base, Greenland.

    Science.gov (United States)

    Pace, Giandomenico; Di Iorio, Tatiana; di Sarra, Alcide; Iaccarino, Antonio; Meloni, Daniela; Mevi, Gabriele; Muscari, Giovanni; Cacciani, Marco

    2017-04-01

    A RPG Humidity And Temperature PROfiler (HATPRO-G2 ) radiometer was installed at Thule Air Base (76.5° N, 68.8° W), Greenland, in June 2016 in the framework of the Study of the water VApour in the polar AtmosPhere (SVAAP) project. The Danish Meteorological Institute started measurements of atmospheric properties at Thule Air Base in early '90s. The Thule High Arctic Atmospheric Observatory (THAAO) has grown in size and observing capabilities during the last three decades through the international effort of United States (NCAR and University of Alaska Fairbanks) and Italian (ENEA, INGV, University of Roma and Firenze) institutions (http://www.thuleatmos-it.it). Within this context, the intensive field campaign of the SVAAP project was aimed at the investigation of the surface radiation budget and took place from 5 to 28 July, 2016. After the summer campaign the HATPRO has continued to operate in order to monitor the annual variability of the temperature profile and integrated water vapour as well as the presence and characteristics of liquid clouds in the Artic environment. The combined use of the HATPRO together with other automatic instruments, such as a new microwave spectrometer (the water Vapour Emission Spectrometer for Polar Atmosphere VESPA-22), upward- and downward-looking pyranometers and pyrgeometers, a zenith-looking pyrometer operating in the 9.6-11.5 µm spectral range, an all sky camera, and a meteorological station, allows to investigate the clouds' physical and optical properties, as well as their impact on the surface radiation budget. This study will present and discuss the first few months of HATPRO observations; the effectiveness of the statistical retrieval used to derive the physical parameters from the HATPRO brightness temperatures will also be investigated through the comparison of the temperature and humidity profiles, and integrated water vapour, with data from radiosondes launched during the summer campaign and in winter time.

  2. Pneumatization and otitis media in Greenlandic Inuit before European colonization

    DEFF Research Database (Denmark)

    Homøe, P; Lynnerup, N; Skovgaard, L T

    1995-01-01

    A total of 127 Greenlandic Inuit crania from before the European colonization of Greenland and deriving from the West (W), Southeast (SE), and Northeast (NE) coast of Greenland were examined for sequelae of infectious middle ear disease (IMED) and for a relationship between the size of the pneuma...

  3. Micro- and mesozooplankton in Southwest Greenland waters in relation to environmental factors

    DEFF Research Database (Denmark)

    Pedersen, S.A.; Ribergaard, M.H.; Stenberg, Claus

    2005-01-01

    Plankton samples and oceanographic data were obtained during transect studies across fishing banks over the Southwest Greenland shelf in June 1999, May, and July 2000. The study gives a detailed description of micro- and mesozooplankton distributions and community structures during spring bloom a...

  4. Roughhead grenadier (Macrourus berglax) in the waters off East Greenland: Distribution and biology

    DEFF Research Database (Denmark)

    Fossen, Inge; Jørgensen, Ole A; Gundersen, Agnes C.

    2003-01-01

    The study focuses on distribution, catch rates and biological parameters of roughhead grenadier (Macrourus berglax) at East Greenland based on data from trawl surveys, longline surveys and commercial catches from the period 1994-2000. Roughhead grenadier was recorded at most fished stations...

  5. Effect of twine diameter on fishing power of experimental gill nets used in Greenland waters

    DEFF Research Database (Denmark)

    Hovgård, Holger

    1996-01-01

    The relative fishing powers of experimental gill nets were estimated for shorthorn sculpin (Myoxocephalus scorpius), Greenland cod (Gadus ogac), and Atlantic cod (Gadus morhua). The results suggested that fishing power was negatively correlated to the ratio between twine diameter and mesh size....... Similar differences in fishing power could be inferred for American plaice (Hippoglossoides platessoides) where no mesh- size selection was evident....

  6. Coccolithophores in Polar Waters: Papposphaera sarion HET and HOL revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Heldal, Mikal; Østergaard, Jette B.

    2016-01-01

    Papposphaera sarion was first described from West Greenland waters and has not since then been reported from other sites. We present here additional material of P. sarion from the type locality, transmission electron images of P. sarion from the NEW polynya (NE Greenland) and scanning electron im...

  7. Seawater-like trace element signatures (REE + Y) of Eoarchaean chemical sedimentary rocks from southern West Greenland, and their corruption during high-grade metamorphism

    Science.gov (United States)

    Friend, C. R. L.; Nutman, A. P.; Bennett, V. C.; Norman, M. D.

    2008-02-01

    Modern chemical sediments display a distinctive rare earth element + yttrium (REE + Y) pattern involving depleted LREE, positive La/La*SN, Eu/Eu*SN, and YSN anomalies (SN = shale normalised) that is related to precipitation from circumneutral to high pH waters with solution complexation of the REEs dominated by carbonate ions. This is often interpreted as reflecting precipitation from surface waters (usually marine). The oldest broadly accepted chemical sediments are c. 3,700 Ma amphibolite facies banded iron-formation (BIF) units in the Isua supracrustal belt, Greenland. Isua BIFs, including the BIF international reference material IF-G are generally considered to be seawater precipitates, and display these REE + Y patterns (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004). Greenland Eoarchaean BIF metamorphosed up to granulite facies from several localities in the vicinity of Akilia (island), display REE + Y patterns identical to Isua BIF, consistent with an origin by chemical sedimentation from seawater and a paucity of clastic input. Furthermore, the much-debated magnetite-bearing siliceous unit of “earliest life” rocks (sample G91/26) from Akilia has the same REE + Y pattern. This suggests that sample G91/26 is also a chemical sediment, contrary to previous assertions (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004), and including suggestions that the Akilia unit containing G91/26 consists entirely of silica-penetrated, metasomatised, mafic rock (Fedo and Whitehouse 2002a). Integration of our trace element data with those of Bolhar et al. (Earth Planet Sci Lett 222:43 60, 2004) demonstrates that Eoarchaean siliceous rocks in Greenland, with ages from 3.6 to 3.85 Ga, have diverse trace element signatures. There are now geographically-dispersed, widespread examples with Isua BIF-like REE + Y signatures, that are interpreted as chemically unaltered, albeit metamorphosed, chemical sediments. Other samples retain remnants of LREE depletion but

  8. Phytoplankton Productivity in an Arctic Fjord (West Greenland): Estimating Electron Requirements for Carbon Fixation and Oxygen Production.

    Science.gov (United States)

    Hancke, Kasper; Dalsgaard, Tage; Sejr, Mikael Kristian; Markager, Stiig; Glud, Ronnie Nøhr

    2015-01-01

    Accurate quantification of pelagic primary production is essential for quantifying the marine carbon turnover and the energy supply to the food web. Knowing the electron requirement (Κ) for carbon (C) fixation (ΚC) and oxygen (O2) production (ΚO2), variable fluorescence has the potential to quantify primary production in microalgae, and hereby increasing spatial and temporal resolution of measurements compared to traditional methods. Here we quantify ΚC and ΚO2 through measures of Pulse Amplitude Modulated (PAM) fluorometry, C fixation and O2 production in an Arctic fjord (Godthåbsfjorden, W Greenland). Through short- (2h) and long-term (24h) experiments, rates of electron transfer (ETRPSII), C fixation and/or O2 production were quantified and compared. Absolute rates of ETR were derived by accounting for Photosystem II light absorption and spectral light composition. Two-hour incubations revealed a linear relationship between ETRPSII and gross 14C fixation (R2 = 0.81) during light-limited photosynthesis, giving a ΚC of 7.6 ± 0.6 (mean ± S.E.) mol é (mol C)-1. Diel net rates also demonstrated a linear relationship between ETRPSII and C fixation giving a ΚC of 11.2 ± 1.3 mol é (mol C)-1 (R2 = 0.86). For net O2 production the electron requirement was lower than for net C fixation giving 6.5 ± 0.9 mol é (mol O2)-1 (R2 = 0.94). This, however, still is an electron requirement 1.6 times higher than the theoretical minimum for O2 production [i.e. 4 mol é (mol O2)-1]. The discrepancy is explained by respiratory activity and non-photochemical electron requirements and the variability is discussed. In conclusion, the bio-optical method and derived electron requirement support conversion of ETR to units of C or O2, paving the road for improved spatial and temporal resolution of primary production estimates.

  9. Phytoplankton Productivity in an Arctic Fjord (West Greenland: Estimating Electron Requirements for Carbon Fixation and Oxygen Production.

    Directory of Open Access Journals (Sweden)

    Kasper Hancke

    Full Text Available Accurate quantification of pelagic primary production is essential for quantifying the marine carbon turnover and the energy supply to the food web. Knowing the electron requirement (Κ for carbon (C fixation (ΚC and oxygen (O2 production (ΚO2, variable fluorescence has the potential to quantify primary production in microalgae, and hereby increasing spatial and temporal resolution of measurements compared to traditional methods. Here we quantify ΚC and ΚO2 through measures of Pulse Amplitude Modulated (PAM fluorometry, C fixation and O2 production in an Arctic fjord (Godthåbsfjorden, W Greenland. Through short- (2h and long-term (24h experiments, rates of electron transfer (ETRPSII, C fixation and/or O2 production were quantified and compared. Absolute rates of ETR were derived by accounting for Photosystem II light absorption and spectral light composition. Two-hour incubations revealed a linear relationship between ETRPSII and gross 14C fixation (R2 = 0.81 during light-limited photosynthesis, giving a ΚC of 7.6 ± 0.6 (mean ± S.E. mol é (mol C-1. Diel net rates also demonstrated a linear relationship between ETRPSII and C fixation giving a ΚC of 11.2 ± 1.3 mol é (mol C-1 (R2 = 0.86. For net O2 production the electron requirement was lower than for net C fixation giving 6.5 ± 0.9 mol é (mol O2-1 (R2 = 0.94. This, however, still is an electron requirement 1.6 times higher than the theoretical minimum for O2 production [i.e. 4 mol é (mol O2-1]. The discrepancy is explained by respiratory activity and non-photochemical electron requirements and the variability is discussed. In conclusion, the bio-optical method and derived electron requirement support conversion of ETR to units of C or O2, paving the road for improved spatial and temporal resolution of primary production estimates.

  10. Evaluation of the use of common sculpin (Myoxocephalus scorpius) organ histology as bioindicator for element exposure in the fjord of the mining area Maarmorilik, West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Sonne, Christian, E-mail: csh@dmu.dk [Aarhus University, Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde (Denmark); Bach, Lis; Søndergaard, Jens; Rigét, Frank F.; Dietz, Rune; Mosbech, Anders [Aarhus University, Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde (Denmark); Leifsson, Pall S. [University of Copenhagen, Faculty of Health and Medical Sciences, Department of Veterinary Disease Biology, Bülowsvej 17, DK-1870 Frederiksberg (Denmark); Gustavson, Kim [Aarhus University, Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde (Denmark)

    2014-08-15

    The former Black Angel lead–zinc mine in Maarmorilik, West Greenland, is a historic example of how mining activity may result in a significant impact on the surrounding fjord system in terms of elevated concentrations of especially lead (Pb) and zinc (Zn) in seawater, sediments and surrounding biota. In order to shed light on the present contamination and possible effects in the fjord we initiated a range of studies including a pilot study on gill and liver morphology of common sculpins (Myoxocephalus scorpius) around Maarmorilik. Sculpins were caught and sampled at five different stations known to represent a gradient of Pb concentrations. Fish livers from all specimens were analyzed for relevant elements in the area: Fe, Zn, As, Cu, Se, Cd, Pb, Ag, Hg, Co and Ni. Lead, As and Hg showed significant differences among the five stations. For 20% of the sculpins, Hg concentrations were in the range of lowest observed effect dose (LOED) of 0.1–0.5 μg/g ww for toxic threshold on reproduction and subclinical endpoints. Likewise LOEDs for tissue lesions, LOEDs for biochemistry, growth, survival and reproduction were exceeded for Cd (0.42–1.8 μg/g ww) and for As (11.6 μg/g ww) in 28% and 85% of the sculpins, respectively. Similar to this, the no observed effect dose (NOED) for biochemistry was exceeded for Pb (0.32 μg/g ww) and for growth, mortality and reproduction for Zn (60–68 μg/g ww) in 33% and 24% of the sculpins, respectively. For all sculpins, females were significantly larger than males and for five of the elements (Fe, Co, Ni, Cu, Se) females had higher concentrations. The chronic lesions observed in liver (mononuclear cell infiltrates, necrosis, vacuolar hepatocytes, portal fibrosis, bile duct hyperplasia, active melanomacrophage centers) and gills (fusion and edema of secondary lamellae, laminar telangiectasis, mononuclear cell infiltrates, blebs) were similar to those in the literature studies for both wild and laboratory exposed sculpins and

  11. Evaporation and transport of water isotopologues from Greenland lakes: The lake size effect

    Science.gov (United States)

    Feng, Xiahong; Lauder, Alex M.; Posmentier, Eric S.; Kopec, Ben G.; Virginia, Ross A.

    2016-01-01

    Isotopic compositions of evaporative flux from a lake are used in many hydrological and paleoclimate studies that help constrain the water budget of a lake and/or to infer changes in climate conditions. The isotopic fluxes of evaporation from a water surface are typically computed using a zero dimensional (0-D) model originally conceptualized by Craig and Gordon (1965). Such models generally have laminar and turbulent layers, assume a steady state condition, and neglect horizontal variations. In particular, the effect of advection on isotopic variations is not considered. While this classical treatment can be used for some sections of large open surface water bodies, such as an ocean or a large lake, it may not apply to relatively small water bodies where limited fetch does not allow full equilibration between air from land and the water surface. Both horizontal and vertical gradients in water vapor concentration and isotopic ratios may develop over a lake. These gradients, in turn, affect the evaporative fluxes of water vapor and its isotopic ratios, which is not adequately predicted by a 0-D model. We observed, for the first time, the vertical as well as horizontal components of vapor and isotopic gradients as relatively dry and isotopically depleted air advected over the surfaces of several lakes up to a 5 km fetch under winds of 1-5 m/s in Kangerlussuaq, Greenland. We modeled the vapor and isotopic distribution in air above the lake using a steady state 2-D model, in which vertical diffusive transport balances horizontal advection. The model was verified by our observations, and then used to calculate evaporative fluxes of vapor and its isotopic ratios. In the special case of zero wind speed, the model reduces to 1-D. Results from this 1-D model are compared with those from the 2-D model to assess the discrepancy in isotopic fluxes between advection and no advection conditions. Since wind advection above a lake alters the concentrations, gradients, and

  12. Trends of lead and zinc in resident and transplanted Flavocetraria nivalis lichens near a former lead-zinc mine in West Greenland.

    Science.gov (United States)

    Søndergaard, Jens; Johansen, Poul; Asmund, Gert; Rigét, Frank

    2011-09-01

    This study investigated spatial and temporal trends of lead (Pb) and zinc (Zn) in resident and transplanted Flavocetraria nivalis lichens near the former Black Angel Mine in Maarmorilik, West Greenland. The objectives of the study were to evaluate resident and transplanted lichens for monitoring dust contamination and investigate trends in mine-related dust contamination near the mine. The mine operated between 1973 and 1990 and lichens were regularly sampled between 1986 and 2009. When the mine operated, elevated concentrations of Pb, Zn and other elements were observed in resident lichens up to 35 km from Maarmorilik. In the period after mine closure, Pb and Zn concentrations in resident lichens decreased with 1-11% and 0-6% per year, respectively. From 1996 to 2009, lichens were transplanted into the study area from an uncontaminated site and collected the following year. After 1 year, transplanted lichens showed elevated concentrations of Pb and Zn but contained consistently less Pb and Zn compared to resident lichens (24±23% and 63±37%, respectively). During the most recent sampling in 2009, transplanted lichens still showed significantly elevated Pb concentrations (up to a factor 270) within a distance of 20 km from Maarmorilik. Zinc concentrations were only significantly elevated at sites within 5 km from the mine. Time-series regression analyses showed no significant decreases in Pb and Zn in transplanted lichens at any of the sites during the period 1996-2009. In conclusion, our study showed that resident F. nivalis lichens could not be used to evaluate the recent annual dust contamination in Maarmorilik. Lichen transplants, however, were considered adequate for assessing spatial and temporal trends in Pb and Zn contamination from recently deposited dust. The continuous dispersal of contaminated dust in Maarmorilik almost 20 years after mine closure reveals a slow recovery from mining contamination in this arctic area.

  13. Modelling atmospheric bulk deposition of Pb, Zn and Cd near a former Pb-Zn mine in West Greenland using transplanted Flavocetraria nivalis lichens.

    Science.gov (United States)

    Søndergaard, Jens; Bach, Lis; Asmund, Gert

    2013-03-01

    Atmospheric deposition of lead (Pb), zinc (Zn) and cadmium (Cd) was investigated near the former Black Angel Pb-Zn mine in Maarmorilik, West Greenland during 2010-2011. Thalli of the lichen Flavocetraria nivalis were transplanted from an uncontaminated site into sites near the mine and collected the following year. At 20 of the total 21 sites, concentrations of Pb, Zn and Cd were significantly elevated in lichens after 1 year of transplantation compared to initial concentrations. Elevated concentrations were observed within a distance of approx. 20 km from the mining area. Concentrations decreased with increasing distance from the mine and the relation was well described using a power function with a negative exponent (r(2)=0.90; 0.83 and 0.83 for Pb; Zn and Cd). To examine the relation between metal concentrations/uptake in lichen transplants and atmospheric bulk deposition, 10 Bergerhoff dust samplers were placed near lichen transplants and samplers and lichens were collected after a 7-weeks exposure period. A significant linear correlation was observed between metal concentrations in lichen transplants and atmospheric bulk metal deposition (r(2)=0.94; 0.88 and 0.89 for Pb; Zn and Cd). Combining the results and including an area distribution within a defined metal deposition area, the "annual" deposition of Pb, Zn and Cd as dust was estimated during the 2010-2011 snow-free period (∼5 months). The results reveal that 20 years after mine closure, 770 kg Pb, 3700 kg Zn and 24 kg Cd were still being deposited as dust per year (snow-free period only) within a distance of 20 km from the mine.

  14. Recent changes in north-west Greenland climate documented by NEEM shallow ice core data and simulations, and implications for past temperature reconstructions

    Science.gov (United States)

    Masson-Delmotte, V.; Steen-Larsen, H. C.; Ortega, P.; Swingedouw, D.; Popp, T.; Vinther, B. M.; Oerter, H.; Sveinbjornsdottir, A. E.; Gudlaugsdottir, H.; Box, J. E.; Falourd, S.; Fettweis, X.; Gallée, H.; Garnier, E.; Jouzel, J.; Landais, A.; Minster, B.; Paradis, N.; Orsi, A.; Risi, C.; Werner, M.; White, J. W. C.

    2015-01-01

    Combined records of snow accumulation rate, δ18O and deuterium excess were produced from several shallow ice cores and snow pits at NEEM (north-west Greenland), covering the period from 1724 to 2007. They are used to investigate recent climate variability and characterize the isotope-temperature relationship. We find that NEEM records are only weakly affected by inter-annual changes in the North Atlantic Oscillation. Decadal δ18O and accumulation variability is related to North Atlantic SST, and enhanced at the beginning of the 19th century. No long-term trend is observed in the accumulation record. By contrast, NEEM δ18O shows multi-decadal increasing trends in the late 19th century and since the 1980s. The strongest annual positive δ18O anomaly values are recorded at NEEM in 1928 and 2010, while maximum accumulation occurs in 1933. The last decade is the most enriched in δ18O (warmest), while the 11-year periods with the strongest depletion (coldest) are depicted at NEEM in 1815-1825 and 1836-1846, which are also the driest 11-year periods. The NEEM accumulation and δ18O records are strongly correlated with outputs from atmospheric models, nudged to atmospheric reanalyses. Best performance is observed for ERA reanalyses. Gridded temperature reconstructions, instrumental data and model outputs at NEEM are used to estimate the multi-decadal accumulation-temperature and δ18O-temperature relationships for the strong warming period in 1979-2007. The accumulation sensitivity to temperature is estimated at 11 ± 2% °C-1 and the δ18O-temperature slope at 1.1 ± 0.2‰ °C-1, about twice larger than previously used to estimate last interglacial temperature change from the bottom part of the NEEM deep ice core.

  15. The seasonal cycle and interannual variability of surface energy balance and melt in the ablation zone of the west Greenland ice sheet

    Directory of Open Access Journals (Sweden)

    M. van den Broeke

    2011-03-01

    Full Text Available We present the seasonal cycle and interannual variability of the surface energy balance (SEB in the ablation zone of the west Greenland ice sheet, using seven years (September 2003–August 2010 of hourly observations from three automatic weather stations (AWS. The AWS are situated along the 67° N latitude circle at elevations of 490 m a.s.l. (S5, 1020 m a.s.l. (S6 and 1520 m a.s.l. (S9 at distances of 6, 38 and 88 km from the ice sheet margin. The hourly AWS data are fed into a model that calculates all SEB components and melt rate; the model allows for shortwave radiation penetration in ice and time-varying surface momentum roughness. Snow depth is prescribed from albedo and sonic height ranger observations. Modelled and observed surface temperatures for non-melting conditions agree very well, with RMSE's of 0.97–1.26 K. Modelled and observed ice melt rates at the two lowest sites also show very good agreement, both for total cumulative and 10-day cumulated amounts. Melt frequencies and melt rates at the AWS sites are discussed. Although absorbed shortwave radiation is the most important energy source for melt at all three sites, interannual melt variability at the lowest site is driven mainly by variability in the turbulent flux of sensible heat. This is explained by the quasi-constant summer albedo in the lower ablation zone, limiting the influence of the melt-albedo feedback, and the proximity of the snow free tundra, which heats up considerably in summer.

  16. Fauna of Ephemeroptera in the running waters of west Serbia

    Directory of Open Access Journals (Sweden)

    Marković Z.

    2002-01-01

    Full Text Available During the period 1988 - 1996 the Ephemeroptera diversity in West Serbia was studied. These investigations included 124 springs, considerable number of spring regions, as well as rivers: the Sušica, Djetinja, Skrapež Pocibrava, Banja, Gradac, Jablanica, Obnica and Kolubara. Total of 45 taxa belonging to 8 families were identified. At the majority of sampling locations: Baetis rhodani, Baetis sp., Ecdyonurus sp., Ephemera danica Ephemerella ignita, Caenis moesta, Habroleptoides modesta and Ilhitrogena semicolorata were present. The smallest Ephemeroptera diversity in the studied waters was recorded in springs and the greatest one in middle parts of the mountain running waters.

  17. Feeding ecology of capelin (Mallotus villosus Müller) in West Greenland waters

    DEFF Research Database (Denmark)

    Hedeholm, R.; Grønkjær, P.; Rysgaard, Søren

    2012-01-01

    ) were 9.54 ‰ ± 0.72 and 12.47 ‰ ± 0.38 (mean ± SD), respectively. However, when differences in isotopic baseline values (C. finmarchicus δ 15N, 2.47 ‰) in the two areas were taken into account, the isotope values suggest that capelin in the northern areas fed on a slightly higher trophic level higher...... prey by wet weight was euphausiids (61 %) followed by amphipods (18 %) and copepods (10 %). The most common species were Thysanoessa raschii, Themisto libulla, Calanus finmarchicus and Calanus hyperboreus. Copepods dominated in smaller capelin but were replaced by euphausiids in larger fish. A similar...... prey shift towards euphausiids along with an increase in prey weight (relative and absolute) was seen with increasing latitude. The spatial variation in feeding pattern was supported by stable nitrogen analyses. The mean δ 15N values of capelin muscle tissue for the south (60-64°N) and north (68-72°N...

  18. Coral by-catch in shrimp bottom trawl surveys in West Greenland waters (2010 – 2012)

    DEFF Research Database (Denmark)

    Jørgensbye, Helle; Arboe, Nanette Hammeken

    shrimp stock assessments. A total of 628 hauls were conducted covering an area of 17.1 km2. Sixty-six hauls contained corals and of these 13 hauls had two or more species of corals. Only two hauls contained more than one kilo of coral, which were in each case comprised of one only species...... within which shrimp are fished. This first analysis suggests that dense fields of Sea Pens and patches of octocorals occur in the depth range and within the area covered by the shrimp fishery...

  19. Phytoplankton growth and microzooplankton grazing along a sub-Arctic fjord (Godthåbsfjord, West Greenland)

    DEFF Research Database (Denmark)

    Calbet, A.; Riisgaard, Karen; Saiz, E.

    2011-01-01

    we established four zones: i) Fyllas Bank, characterized by deep chl a maxima (ca. 30-40 m) consisting of large cells; ii) the mouth and main branch of the fjord, where phytoplankton was relatively homogeneously distributed in the upper 30 m layer; iii) inner waters influenced by glacial melt water...... and upwelling, with high chl a concentrations (up to 12 µg L-1) in the > 10 µm fraction within a narrow (2 m) subsurface layer; and iv) the Kapisigdlit branch of the fjord, ice-free, and characterized with a thick and deep chl a maximum layer. Overall, microzooplankton grazing impact on primary production...

  20. South Greenland

    DEFF Research Database (Denmark)

    This report is a preliminary strategic environmental impact assessment of activities related to exploration, development and exploitation of oil in the Greenland sector of the Labrador Sea and the southeast Davis Strait......This report is a preliminary strategic environmental impact assessment of activities related to exploration, development and exploitation of oil in the Greenland sector of the Labrador Sea and the southeast Davis Strait...

  1. Retention of fish larvae in a fjord system - a seasonal study of the larval life in a West Greenlandic fjord

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus; Munk, Peter; Nielsen, Torkel Gissel

    larval species was recorded from late March to early August along a 25 km transect covering the length of the fjord branch. Cod spawning started when the upper 20 m of the water column had reached a temperature of 2° C, and cod larvae abundances peaked on June 3rd (16 larvae per 100 m3) in the inner...

  2. Early life of key fish species, capelin Mallotus villosus and Atlantic cod Gadus morhua, in West Greenland

    DEFF Research Database (Denmark)

    Malanski, Evandro

    feeding on prey sizes of about 5% of their own size (Paper I) and consequently the prey preference spectra covered calanoid nauplii, cladocerans and calanoid copepodites with increasing larval size. In the Godthåbsfjord system and Fyllas Bank area, 4 hydrographic zones were defined; in each zone distinct...... is linked to the break-up of ice cover and the subsequent irradiance increase in the water column, climatic changes in Arctic regions could lead to a mismatch between larval emergence and optimal conditions for their feeding and growth. Thus it would be feasible to investigate the capelin stock genetic...

  3. Species of Thaumatomastix (Thaumatomastigidae, Protista incertae sedis) from the Arctic sea ice biota (North-East Water Polynya, NE Greenland)

    Science.gov (United States)

    Thomsen, Helge Abildhauge; Ikävalko, Johanna

    1997-01-01

    The sea ice biota of polar regions contains numerous heterotrophic flagellates very few of which have been properly identified. The whole mount technique for transmission electron microscopy enables the identification of loricate and scaly forms. A survey of Arctic ice samples (North-East Water Polynya, NE Greenland) revealed the presence of ca. 12 taxa belonging to the phagotrophic genus Thaumatomastix (Protista incertae sedis). Species of Thaumatomastix possess siliceous body scales and one naked and one scale-covered flagellum. The presence in both Arctic samples and sea ice material previously examined from the Antarctic indicates that this genus is most likely ubiquitous in polar sea ice and may be an important component in sea ice biota microbial activities.

  4. Marine algae inform past calving rates of a tide water glacier in western Greenland.

    Science.gov (United States)

    Schoenrock, Kathryn; Kamenos, Nicholas; Mair, Douglas; Lea, James; Rea, Brice; Schofield, James; Pearce, Danni

    2017-04-01

    Coralline algae are ubiquitous in marine environments worldwide acting as ecosystem engineers by cementing reefs together and providing habitat for local communities. The calcified thallus also makes coralline algae repository for past environmental conditions, providing information on the scale of 10s-100s of years. Free living coralline algae, or maerl, can dominate local habitats along the coasts and in fjord systems of western Greenland. Using the long lived maerl species, Lithothamnion glaciale, we present multi-proxy data sets for the large fjord system adjacent to the Kangiata Nunâta Sermia (KNS) glacier. This information provides a record of glacial movement (advance and retreat) and calving for the past 70+ years which can be correlated to records of glacial calving. The KNS glacier is one of the largest tidewater glaciers in western Greenland and contributes to the mass transfer of glaciers and ice sheets into the world oceans. The present data combined with terrestrial proxies within the CALVE research project will help inform policy and models focusing on future climate conditions.

  5. Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model

    Directory of Open Access Journals (Sweden)

    R. Marsh

    2009-11-01

    Full Text Available In a sensitivity experiment, an eddy-permitting ocean general circulation model is forced with freshwater fluxes from the Greenland Ice Sheet, averaged for the period 1991–2000. The fluxes are obtained with a mass balance model for the ice sheet, forced with the ERA-40 reanalysis dataset. The freshwater flux is distributed around Greenland as an additional term in prescribed runoff, representing seasonal melting of the ice sheet and a fixed year-round iceberg calving flux, for 8.5 model years. The impacts on regional hydrography and circulation are investigated by comparing the sensitivity experiment to a control experiment, without Greenland fluxes. By the end of the sensitivity experiment, the majority of additional fresh water has accumulated in Baffin Bay, and only a small fraction has reached the interior of the Labrador Sea, where winter mixed layer depth is sensitive to small changes in salinity. As a consequence, the impact on large-scale circulation is very slight. An indirect impact of strong freshening off the west coast of Greenland is a small anti-cyclonic circulation around Greenland which opposes the wind-driven cyclonic circulation and reduces net southward flow through the Canadian Archipelago by ~10%. Implications for the post-2000 acceleration of Greenland mass loss are discussed.

  6. Retention of fish larvae in a fjord system - a seasonal study of the larval life in a West Greenlandic fjord

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus; Munk, Peter; Nielsen, Torkel Gissel

    in the early part of the spawning season, while later in the season we found larvae dispersing out through the fjord branch. Considering larval sizes and migratory ability these patterns could be due to seasonal changes in hydrography and tidal flow that may facilitate their dispersal...... (Hippoglossoides platessoides) are abundant. The innermost part of the fjord branch Kapisigdlit is the principal spawning site for the fjord population of Atlantic cod, and in 2010 a seasonal study was carried out on the early life of this population. Abundance and distribution of this and other occurring fish...... larval species was recorded from late March to early August along a 25 km transect covering the length of the fjord branch. Cod spawning started when the upper 20 m of the water column had reached a temperature of 2° C, and cod larvae abundances peaked on June 3rd (16 larvae per 100 m3) in the inner...

  7. The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event

    Science.gov (United States)

    Bonne, Jean-Louis; Steen-Larsen, Hans Christian; Risi, Camille; Werner, Martin; Sodemann, Harald; Lacour, Jean-Lionel; Fettweis, Xavier; Cesana, Grégory; Delmotte, Marc; Cattani, Olivier; Vallelonga, Paul; Kjær, Helle Astrid; Clerbaux, Cathy; Sveinbjörnsdóttir, Árny Erla; Masson-Delmotte, Valérie

    2015-04-01

    During 7-12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut), and northwest Greenland ice sheet (NEEM), as well as remote sensing observations (Infrared Atmospheric Sounding Interferometer (IASI) instrument on board MetOp-A), depicting propagation of similar surface and midtropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity, and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting ˜100‰δD enrichment and ˜15‰ deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapor isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to northwest Greenland.

  8. Migration and breeding biology of arctic terns in Greenland

    DEFF Research Database (Denmark)

    Egevang, Carsten

    (Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... by the distribution of breeding Arctic terns as suggested by Egevang et al. (2004). Included in the thesis are furthermore results with an appeal to the Greenland management agencies. Along with estimates of the Arctic tern population size at the two most important Arctic tern colonies in West Greenland and East...

  9. Using Water Vapor Isotope Observations from above the Greenland Ice Sheet to improve the Interpretation of Ice Core Water Stable Isotope Records

    Science.gov (United States)

    Steen-Larsen, H. C.; Masson-Delmotte, V.; Risi, C. M.; Yoshimura, K.; Werner, M.; Butzin, M.; Brun, E.; Landais, A.; Bonne, J. L.; Dahl-Jensen, D.

    2014-12-01

    Water stable isotope data from Greenland ice cores provide key paleoclimatic information. For the purpose of improving the climatic interpretation from ice core records, a monitoring of the isotopic composition δ18O and δD at several height levels (up to 13 meter) of near-surface water vapor, precipitation and snow in the first 0.5 cm surface layer has been conducted during three summers (2010-2012) at NEEM, NW Greenland. We compare the observed water vapor isotopic composition with model outputs from three isotope-enabled general circulation models: LMDZiso, isoGSM, ECHAM-wiso. This allows us to benchmark the models and address effect of model resolution, effect of transport, effect of isotope parameterization, and representation of significant source region contributions. We find for all models that the simulated isotopic value δD are significantly biased towards too enriched values. A bias, which is only partly explained by the air temperature. The simulated amplitude in d-excess variations is ~50% smaller than observed and the simulated average summer level is ~10‰ lower than in observations. Using back trajectories we observe water vapor of Arctic origin to have a high d-excess fingerprint. This fingerprint is not observed in the GCMiso simulations indicating a problem of simulating accurately the Arctic hydrological cycle. The bias in the simulated δD and d-excess water vapor is similar to the already-documented bias in the simulated δD and d-excess of Greenland ice core records. This suggests that if we improve the simulation of the water vapor isotopic composition we might also improve the simulation of the ice core isotope record. During periods between precipitation events, our data demonstrate parallel changes of δ18O and d-excess in surface snow and near-surface vapor. The changes in δ18O of the vapor are similar or larger than those of the snow δ18O. It is estimated using the CROCUS snow model that 6 to 20% of the surface snow mass is

  10. A Financial, Environmental and Social Evaluation of Domestic Water Management Options in the West Bank, Palestine

    NARCIS (Netherlands)

    Nazer, D.W.; Siebel, M.A.; Van der Zaag, P.; Mimi, Z.; Gijzen, H.J.

    2010-01-01

    Water is one of the most valuable natural resources in the West Bank, Palestine. Due to its limited availability, it is a resource that needs particular protection. Although agriculture consumes most of the water (70%) in the West Bank, the domestic water supply is strategically not less important.

  11. Avoidable deaths in Greenland 1968-1985

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Juel, K

    1990-01-01

    and several showed an increasing time trend. The regional patterns were particularly clear for infectious diseases and accidents, which showed low mortality rates in the capital and other towns and high mortality rates in settlements and in the remote East Greenland, while mortality rates from suicides...... and political will of the society. A list of avoidable deaths is proposed for Greenland which includes, inter alia, meningitis, lung cancer, acute respiratory infections, suicides, boat accidents and alcohol related diseases and accidents. All were considerably more common in Greenland than in Denmark...... and alcohol related diseases were high in the capital and East Greenland and low in West Greenlandic settlements. It is concluded that further studies on preventable diseases and causes of death, in particular certain infectious diseases, accidents and suicides, are needed....

  12. Climate versus in-lake processes as controls on the development of community structure in a low-arctic lake (South-West Greenland)

    DEFF Research Database (Denmark)

    Anderson, N. John; Brodersen, Klaus Peter; Ryves, David B.

    2008-01-01

    The dominant processes determining biological structure in lakes at millennial timescales are complex. In this study, we used a multi-proxy approach to determine the relative importance of in-lake versus indirect processes on the Holocene development of an oligotrophic lake in SW Greenland (66.99°N...

  13. Melting glaciers stimulate large summer phytoplankton blooms in southwest Greenland waters

    Science.gov (United States)

    Arrigo, Kevin R.; van Dijken, Gert L.; Castelao, Renato M.; Luo, Hao; Rennermalm, Ósa K.; Tedesco, Marco; Mote, Thomas L.; Oliver, Hilde; Yager, Patricia L.

    2017-06-01

    Each summer, large quantities of freshwater and associated dissolved and particulate material are released from the Greenland Ice Sheet (GrIS) into local fjords where they promote local phytoplankton growth. Whether the influx of freshwater and associated micronutrients in glacial meltwater is able to stimulate phytoplankton growth beyond the fjords is disputed, however. Here we show that the arrival of freshwater discharge from outlet glaciers from both southeast and southwest GrIS coincides with large-scale blooms in the Labrador Sea that extend over 300 km from the coast during summer. This summer bloom develops about a week after the arrival of glacial meltwater in early July and persists until the input of glacial meltwater slows in August or September, accounting for 40% of annual net primary production for the area. In view of the absence of a significant change in the depth of the mixed layer associated with the arrival of glacial meltwater to the Labrador Sea, we suggest that the increase in phytoplankton biomass and productivity in summer is likely driven by a greater nutrient supply (most likely iron). Our results highlight that the ecological impact of meltwater from the GrIS likely extends far beyond the boundaries of the local fjords, encompassing much of the eastern Labrador Sea. Such impacts may increase if melting of the GrIS accelerates as predicted.

  14. Holocene Development of Greenland Sea Deep Convection: A Comparison of Calcite Surface and Bottom Water δ13c

    Science.gov (United States)

    Bauch, H. A.; Telesinski, M. M.; Spielhagen, R. F.

    2014-12-01

    The northern polar oceans are a crucially important region to understand the overturning circulation of the North Atlantic within the context of glacial-interglacial climate change. Independent of different water mass properties planktic carbon isotope records (13C/12C) from across the Nordic Seas show a rather consistent pattern over the course of the Holocene. We present data from a number of sediment cores obtained in the central Nordic Seas which show that carbon isotope values were increasing since the early Holocene. They reached a maximum level between 7 and 6 ka and remained relatively stable thereafter. Ca. 3 ka they rapidly decreased. Benthic carbon isotope records from the central Nordic Seas, close to the present-day convection center of the Greenland Sea, reveal a similar trend as the planktic records. Although of lower amplitude, these bottom water data reflect the development of the regional deep convection in this region. A comparison with other proxy records and modelling results supports this presumption. While the early to late Holocene trend apparently reflect the developing deep convection after the last glacial period, the sudden decrease in the convection strength around 3 ka was most probably triggered by a strong solar irradiance minimum. This, combined with low insolation, caused an expansion of the sea ice over the convection center and enhanced stratification, thereby strengthening the entire halocline system.

  15. Sedimentary Record and Morphological Effects of a Landslide-Generated Tsunami in a Polar Region: The 2000 AD Tsunami in Vaigat Strait, West Greenland

    Science.gov (United States)

    Szczucinski, W.; Rosser, N. J.; Strzelecki, M. C.; Long, A. J.; Lawrence, T.; Buchwal, A.; Chague-Goff, C.; Woodroffe, S.

    2012-12-01

    To date, the effects of tsunami erosion and deposition have mainly been reported from tropical and temperate climatic zones yet tsunamis are also frequent in polar zones, particularly in fjord settings where they can be generated by landslides. Here we report the geological effects of a landslide-triggered tsunami that occurred on 21st November 2000 in Vaigat, northern Disko Bugt in west Greenland. To characterise the typical features of this tsunami we completed twelve detailed coastal transects in a range of depositional settings: cliff coasts, narrow to moderate width coastal plains, lagoons and a coastal lake. At each setting we completed a detailed map using a laser scanner and DGPS survey. The tsunami deposits were described from closely spaced trenches and, from the lake, by a series of sediment cores . At each setting we examined the sedimentological properties of the deposits, as well as their bulk geochemistry and diatom content. Selected specimens of arctic willow from inundated and non-inundated areas were collected to assess the impact of the event in their growth ring records. Samples of sediments beneath the AD 2000 deposit were studied for 137Cs to confirm the age of the tsunami and to assess the extent of erosion. Offshore sediment samples, modern beach and soils/sediments underlying the AD 2000 tsunami deposits were sampled to determine tsunami deposit sources. The observed tsunami run-up exceeded 20 m next to the tsunami trigger - a rock avalanche at Paatuut - and up to 10 m on the opposite coast of the fjord. The inland inundation distance ranged from several tens of meters to over 300 m. The wave was recorded as far as 180 km away from the source. The tsunami inundated the coast obliquely to the shoreline in all locations studied. The tsunami frequently caused erosion of existing beach ridges whilst erosional niches were formed inland. The tsunami deposits mainly comprise gravels and very coarse sand. They are over 30 cm thick close to the

  16. Evaluation of the use of common sculpin (Myoxocephalus scorpius) organ histology as bioindicator for element exposure in the fjord of the mining area Maarmorilik, West Greenland.

    Science.gov (United States)

    Sonne, Christian; Bach, Lis; Søndergaard, Jens; Rigét, Frank F; Dietz, Rune; Mosbech, Anders; Leifsson, Pall S; Gustavson, Kim

    2014-08-01

    The former Black Angel lead-zinc mine in Maarmorilik, West Greenland, is a historic example of how mining activity may result in a significant impact on the surrounding fjord system in terms of elevated concentrations of especially lead (Pb) and zinc (Zn) in seawater, sediments and surrounding biota. In order to shed light on the present contamination and possible effects in the fjord we initiated a range of studies including a pilot study on gill and liver morphology of common sculpins (Myoxocephalus scorpius) around Maarmorilik. Sculpins were caught and sampled at five different stations known to represent a gradient of Pb concentrations. Fish livers from all specimens were analyzed for relevant elements in the area: Fe, Zn, As, Cu, Se, Cd, Pb, Ag, Hg, Co and Ni. Lead, As and Hg showed significant differences among the five stations. For 20% of the sculpins, Hg concentrations were in the range of lowest observed effect dose (LOED) of 0.1-0.5 μg/g ww for toxic threshold on reproduction and subclinical endpoints. Likewise LOEDs for tissue lesions, LOEDs for biochemistry, growth, survival and reproduction were exceeded for Cd (0.42-1.8 μg/g ww) and for As (11.6 μg/g ww) in 28% and 85% of the sculpins, respectively. Similar to this, the no observed effect dose (NOED) for biochemistry was exceeded for Pb (0.32 μg/g ww) and for growth, mortality and reproduction for Zn (60-68 μg/g ww) in 33% and 24% of the sculpins, respectively. For all sculpins, females were significantly larger than males and for five of the elements (Fe, Co, Ni, Cu, Se) females had higher concentrations. The chronic lesions observed in liver (mononuclear cell infiltrates, necrosis, vacuolar hepatocytes, portal fibrosis, bile duct hyperplasia, active melanomacrophage centers) and gills (fusion and edema of secondary lamellae, laminar telangiectasis, mononuclear cell infiltrates, blebs) were similar to those in the literature studies for both wild and laboratory exposed sculpins and other fish

  17. Satellite observation of winter season subsurface liquid melt water retention on the Greenland ice sheet using spectroradiometer and scatterometer data

    Science.gov (United States)

    Miller, J. Z.; Forster, R. R.; Long, D. G.; Brewer, S.

    2013-12-01

    The recently discovered perennial firn aquifer (PFA) represents a new glacier facie and a previously undefined liquid water storage mechanism on the Greenland ice sheet (GrIS). The current hypothesis suggests that at least two geophysical processes control the formation of the PFA: 1) high melt rates that saturate snow and firn layers with liquid water during the melt season, and 2) high snow accumulation rates that subsequently insulate this saturated layer allowing it to be retained in liquid form during the winter season. The PFA is potentially an important component in ice sheet mass and energy budget calculations, however, large-scale observations linking surface melt, subsurface liquid melt water retention, and the PFA currently do not exist. Satellite-borne spectroradiometers and scatterometers are frequently used to detect the presence of liquid water content over the GrIS. The sensor's penetration depth is dependent on the frequency (which determines wavelength) and time-varying geophysical properties (which determine absorption and scattering characteristics). At shorter spectral wavelengths, penetration depths are limited at the interface between the ice sheet surface and the atmosphere. Spectroradiometer-derived retrievals of liquid water content represent an integrated response on the order of a few millimeters. At longer microwave wavelengths (C- and Ku-band), penetration depths are increased. Scatterometer-derived retrievals of liquid water content represent an integrated response on the order of a few centimeters to several meters. We combine spectroradiometer data acquired from the Moderate Resolution Imaging Spectroradiometer aboard Terra and Aqua (MODIS) and C- and Ku-band scatterometer data acquired from MetOP-A (ASCAT) and OceanSAT-2 (OSCAT) to investigate the spatiotemporal variability of subsurface liquid water content on the GrIS. Penetration depth differences are exploited to distinguish between the detection of liquid water content

  18. Hydrogeology and water quality of the Leetown area, West Virginia

    Science.gov (United States)

    Kozar, Mark D.; McCoy, Kurt J.; Weary, David J.; Field, Malcolm S.; Pierce, Herbert A.; Schill, William Bane; Young, John A.

    2008-01-01

    The U.S. Geological Survey’s Leetown Science Center and the co-located U.S. Department of Agriculture’s National Center for Cool and Cold Water Aquaculture both depend on large volumes of cold clean ground water to support research operations at their facilities. Currently, ground-water demands are provided by three springs and two standby production wells used to augment supplies during periods of low spring flow. Future expansion of research operations at the Leetown Science Center is dependent on assessing the availability and quality of water to the facilities and in locating prospective sites for additional wells to augment existing water supplies. The hydrogeology of the Leetown area, West Virginia, is a structurally complex karst aquifer. Although the aquifer is a karst system, it is not typical of most highly cavernous karst systems, but is dominated by broad areas of fractured rock drained by a relatively small number of solution conduits. Characterization of the aquifer by use of fluorometric tracer tests, a common approach in most karst terranes, therefore only partly defines the hydrogeologic setting of the area. In order to fully assess the hydrogeology and water quality in the vicinity of Leetown, a multi-disciplinary approach that included both fractured rock and karst research components was needed. The U.S. Geological Survey developed this multi-disciplinary research effort to include geologic, hydrologic, geophysical, geographic, water-quality, and microbiological investigations in order to fully characterize the hydrogeology and water quality of the Leetown area, West Virginia. Detailed geologic and karst mapping provided the framework on which hydrologic investigations were based. Fracture trace and lineament analysis helped locate potential water-bearing fractures and guided installation of monitoring wells. Monitoring wells were drilled for borehole geophysical surveys, water-quality sampling, water-level measurements, and aquifer tests to

  19. Greenland ice sheet motion insensitive to exceptional meltwater forcing

    OpenAIRE

    Tedstone, Andrew J.; P. W. Nienow; A. J. Sole; D. W. F. Mair; Cowton, Tom; I. D. Bartholomew; King, M. A.

    2013-01-01

    Changes to the dynamics of the Greenland ice sheet can be forced by various mechanisms including surface-melt-induced ice acceleration and oceanic forcing of marine-terminating glaciers. We use observations of ice motion to examine the surface melt-induced dynamic response of a land-terminating outlet glacier in south-west Greenland to the exceptional melting observed in 2012. During summer, meltwater generated on the Greenland Ice Sheet (GrIS) surface accesses the ice sheet bed, lubricating ...

  20. Measuring bioavailable metals using diffusive gradients in thin films (DGT) and transplanted seaweed (Fucus vesiculosus), blue mussels (Mytilus edulis) and sea snails (Littorina saxatilis) suspended from monitoring buoys near a former lead-zinc mine in West Greenland.

    Science.gov (United States)

    Søndergaard, Jens; Bach, Lis; Gustavson, Kim

    2014-01-15

    Measuring loads of bioavailable metals is important for environmental assessment near mines and other industrial sources. In this study, a setup of monitoring buoys was tested to assess loads of bioavailable metals near a former Pb-Zn mine in West Greenland using transplanted seaweed, mussels and sea snails. In addition, passive DGT samplers were installed. After a 9-day deployment period, concentrations of especially Pb, Zn and Fe in the species were all markedly elevated at the monitoring sites closest to the mine. Lead concentrations in all three species and the DGT-Pb results showed a significant linear correlation. Zinc and Fe concentrations were less correlated indicating that the mechanisms for Zn and Fe accumulation in the three species are more complex. The results show that there is still a significant load of metals from the mine and that such buoys can be an adequate method to assess present loads of bioavailable metals.

  1. USGS46 Greenland ice core water – A new isotopic reference material for δ2H and δ18O measurements of water

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping; Tarbox, Lauren V.; Lorenz, Jennifer M.; Buck, Bryan

    2015-01-01

    Ice core from Greenland was melted, filtered, homogenised, loaded into glass ampoules, sealed, autoclaved to eliminate biological activity, and calibrated by dual-inlet isotope-ratio mass spectrometry. This isotopic reference material (RM), USGS46, is intended as one of two secondary isotopic reference waters for daily normalisation of stable hydrogen (δ2H) and stable oxygen (δ18O) isotopic analysis of water with a mass spectrometer or a laser absorption spectrometer. The measured δ2H and δ18O values of this reference water were −235.8 ± 0.7‰ and −29.80 ± 0.03‰, respectively, relative to VSMOW on scales normalised such that the δ2H and δ18O values of SLAP reference water are, respectively, −428 and −55.5‰. Each uncertainty is an estimated expanded uncertainty (U = 2uc) about the reference value that provides an interval that has about a 95-percent probability of encompassing the true value. This reference water is available in cases containing 144 glass ampoules that are filled with either 4 ml or 5 ml of water per ampoule.

  2. Aponogeton pollen from the Cretaceous and Paleogene of North America and West Greenland: Implications for the origin and palaeobiogeography of the genus☆

    Science.gov (United States)

    Grímsson, Friðgeir; Zetter, Reinhard; Halbritter, Heidemarie; Grimm, Guido W.

    2014-01-01

    The fossil record of Aponogeton (Aponogetonaceae) is scarce and the few reported macrofossil findings are in need of taxonomic revision. Aponogeton pollen is highly diagnostic and when studied with light microscopy (LM) and scanning electron microscopy (SEM) it cannot be confused with any other pollen types. The fossil Aponogeton pollen described here represent the first reliable Cretaceous and Eocene records of this genus worldwide. Today, Aponogeton is confined to the tropics and subtropics of the Old World, but the new fossil records show that during the late Cretaceous and early Cenozoic it was thriving in North America and Greenland. The late Cretaceous pollen record provides important data for future phylogenetic and phylogeographic studies focusing on basal monocots, especially the Alismatales. The Eocene pollen morphotypes from North America and Greenland differ in morphology from each other and also from the older Late Cretaceous North American pollen morphotype, indicating evolutionary trends and diversification within the genus over that time period. The presence of Aponogeton in the fossil record of North America and Greenland calls for a reconsideration of all previous ideas about the biogeographic history of the family. PMID:24926107

  3. Aponogeton pollen from the Cretaceous and Paleogene of North America and West Greenland: Implications for the origin and palaeobiogeography of the genus.

    Science.gov (United States)

    Grímsson, Friðgeir; Zetter, Reinhard; Halbritter, Heidemarie; Grimm, Guido W

    2014-01-01

    The fossil record of Aponogeton (Aponogetonaceae) is scarce and the few reported macrofossil findings are in need of taxonomic revision. Aponogeton pollen is highly diagnostic and when studied with light microscopy (LM) and scanning electron microscopy (SEM) it cannot be confused with any other pollen types. The fossil Aponogeton pollen described here represent the first reliable Cretaceous and Eocene records of this genus worldwide. Today, Aponogeton is confined to the tropics and subtropics of the Old World, but the new fossil records show that during the late Cretaceous and early Cenozoic it was thriving in North America and Greenland. The late Cretaceous pollen record provides important data for future phylogenetic and phylogeographic studies focusing on basal monocots, especially the Alismatales. The Eocene pollen morphotypes from North America and Greenland differ in morphology from each other and also from the older Late Cretaceous North American pollen morphotype, indicating evolutionary trends and diversification within the genus over that time period. The presence of Aponogeton in the fossil record of North America and Greenland calls for a reconsideration of all previous ideas about the biogeographic history of the family.

  4. Growth of wild muskoxen under two nutritional regimes in Greenland

    DEFF Research Database (Denmark)

    Aastrup, Peter; Thing, Henning; Olesen, Carsten Riis

    1994-01-01

    Growth of muskoxen in Jameson Land, East Greenland (EG) and in Angujaartorfiup Nunaa, West Greenland (WG) is affected by the different nutritional conditions in the two areas. The abundance and availability of forage plants is highest in WG. Muskoxen in WG reach sexual maturity one year earlier...

  5. Modelling Greenland icebergs

    Science.gov (United States)

    Marson, Juliana M.; Myers, Paul G.; Hu, Xianmin

    2017-04-01

    The Atlantic Meridional Overturning Circulation (AMOC) is well known for carrying heat from low to high latitudes, moderating local temperatures. Numerical studies have examined the AMOC's variability under the influence of freshwater input to subduction and deep convections sites. However, an important source of freshwater has often been overlooked or misrepresented: icebergs. While liquid runoff decreases the ocean salinity near the coast, icebergs are a gradual and remote source of freshwater - a difference that affects sea ice cover, temperature, and salinity distribution in ocean models. Icebergs originated from the Greenland ice sheet, in particular, can affect the subduction process in Labrador Sea by decreasing surface water density. Our study aims to evaluate the distribution of icebergs originated from Greenland and their contribution to freshwater input in the North Atlantic. To do that, we use an interactive iceberg module coupled with the Nucleus for European Modelling of the Ocean (NEMO v3.4), which will calve icebergs from Greenland according to rates established by Bamber et al. (2012). Details on the distribution and trajectory of icebergs within the model may also be of use for understanding potential navigation threats, as shipping increases in northern waters.

  6. Wastewater Treatment in Greenland

    DEFF Research Database (Denmark)

    Gunnarsdottir, Ragnhildur

    The Arctic nature is vulnerable to environmental contaminants because of low biological diversity, lack of nutrients and extreme seasonal variations in light. In Greenland neither industrial nor domestic wastewater is treated before it is discharged to the recipients, which in most cases is the sea...... treatment in these regions. However, designing, constructing and operating wastewater collection systems in the Arctic is challenging because of e.g. permafrost conditions, hard rock surfaces, freezing, limited quantity of water and high costs of electricity, fuel and transportation, as well as a settlement...... collection systems, and be more economically and environmentally sustainable than traditional wastewater collection and treatment systems. Possible alternative wastewater treatment methods for Greenlandic communities are dry composting or anaerobic digestion of excreta, collected at household level using dry...

  7. Arctic cyclone water vapor isotopes support past sea ice retreat recorded in Greenland ice

    OpenAIRE

    Eric S. Klein; J. E. Cherry; Young, J.; D. Noone; A. J. Leffler; Welker, J.M.

    2015-01-01

    Rapid Arctic warming is associated with important water cycle changes: sea ice loss, increasing atmospheric humidity, permafrost thaw, and water-induced ecosystem changes. Understanding these complex modern processes is critical to interpreting past hydrologic changes preserved in paleoclimate records and predicting future Arctic changes. Cyclones are a prevalent Arctic feature and water vapor isotope ratios during these events provide insights into modern hydrologic processes that help expla...

  8. Active predation by Greenland shark Somniosus microcephalus

    DEFF Research Database (Denmark)

    Nielsen, Julius; hedeholm, Rasmus; Simon, Malene

    2013-01-01

    Dansk Havforskermøde 2013 Julius Nielsen, Rasmus Hedeholm, Malene Simon og John Fleng Steffensen The Greenland shark is ubiquitous in the northern part of the North Atlantic ranging from eastern Canada to northwest Russia . Although knowledge is scarce it is believed to be abundant and potentially...... important part of the ecosystem. Whether Greenland sharks in general should be considered opportunistic scavengers or active predators is therefore important in understanding ecosystem dynamics. Due to its sluggish appearance and a maximum reported swimming speed of 74 cm per second scavenging seems...... the most likely feeding strategy. However, recent studies suggest that Greenland sharks in some areas feed actively upon seals . Feeding ecology is poorly described in Greenland waters. In this study we provide information on feeding habits of 29 sharks caught in Greenland waters in the summer 2012...

  9. From Arctic greenhouse to icehouse: the Cenozoic development of the West Greenland-Baffin Bay margin and the case for scientific drilling

    Science.gov (United States)

    Knutz, Paul; Gregersen, Ulrik; Hopper, John R.; Dybkjær, Karen; Nøhr-Hansen, Henrik; Sheldon, Emma; Huuse, Mads

    2016-04-01

    The long-term evolution of glaciated margins plays an essential role in understanding the driving forces and interactions that determine the build-up and decay of ice sheets. The Greenland continental margin towards Baffin Bay is densely covered by industry seismic data and several exploration wells have been drilled, providing a regional stratigraphic framework for the sedimentary successions. This presentation provides an overview of the major depositional units and stratigraphy of the mid-late Cenozoic (since mid-Eocene), with examples demonstrating the different processes that have formed this margin. A sedimentary succession up to 3.5 km thick, of mid-Eocene to mid-Miocene age (mega-unit D), infills the pronounced ridge-basin structures of the rifted and tectonically inverted margin. The lower part of this interval, presumably late Eocene-Oligocene in age, is interpreted as basin-floor fan deposits, while the upper section, of early-middle Miocene age, is mainly marine mudstone. The basin infilling strata are overlain by a late Miocene-Pliocene succession consisting of two mega-units (B and C), with typical thicknesses of 0.5-1 km. The units are characterised by upslope-climbing sediment waves and along-slope trending sedimentary prisms reminiscent of giant contourite drifts. The borehole data associates the prism accumulations with a deep shelf environment influenced by strong marine currents and nearby fluvial sources. On the slope and in the deep basin of Baffin Bay the late Neogene succession is strongly influenced by mass wasting correlated with erosional scars updip. The uppermost seismic mega-unit (A) is dominated by aggradational wedges and prograding fan deposits displaying depocentres >3 km thick, formed at the terminus of palaeo-ice streams. Borehole information associates this interval with deposition of primarily diamict sediments and suggests a late Pliocene onset of major shelf based glaciations on the NW Greenland margin. The southwest margin

  10. Hydrological and meteorological investigations in a periglacial lake catchment near Kangerlussuaq, west Greenland – presentation of a new multi-parameter dataset

    Directory of Open Access Journals (Sweden)

    E. Johansson

    2014-12-01

    Full Text Available Few hydrological studies have been made in Greenland, other than on glacial hydrology associated with the ice sheet. Understanding permafrost hydrology and hydroclimatic change and variability, however, provides key information for understanding climate change effects and feedbacks in the Arctic landscape. This paper presents a new extensive and detailed hydrological and meteorological open access dataset, with high temporal resolution from a 1.56 km2 permafrost catchment with a lake underlain by a through talik close to the ice sheet in the Kangerlussuaq region, western Greenland. The paper describes the hydrological site investigations and utilized equipment, as well as the data collection and processing. The investigations were performed between 2010 and 2013. The high spatial resolution, within the investigated area, of the dataset makes it highly suitable for various detailed hydrological and ecological studies on catchment scale. The dataset is availble for all users via the PANGAEA database, http://doi.pangaea.de/10.1594/PANGAEA.836178. Please note this dataset is under review and recommended not to be used before the final version of the manuscript is accepted for publication.

  11. Water-Data Report 433802088410401 West Branch Rock River nr Waupun WI 2013

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Streamflow and water quality parameters recorded on the West Branch Rock River near Horicon NWR; 2013. Location is Latitude 43 deg 38' 02", longitude 88 deg 41' 04",...

  12. Life history parameters of narwhals (Monodon monoceros) from Greenland

    DEFF Research Database (Denmark)

    Garde, Eva; Hansen, Steen H; Ditlevsen, Susanne

    2015-01-01

    Life history parameters for narwhals (Monodon monoceros) were estimated based on age estimates from aspartic acid racemization of eye lens nuclei. Eyes, reproductive organs, and measures of body lengths were collected from 282 narwhals in East and West Greenland in the years 1993, 2004, and 2007...... projection matrix was parameterized with the data on age structure and fertility rates. The annual rate of increase of narwhals in East Greenland was estimated to be 3.8% while narwhals in West Greenland had a rate of increase at 2.6%. Key words:...

  13. Public Perception of Potable Water Supply in Abeokuta South west ...

    African Journals Online (AJOL)

    The perception of residents towards the supply of potable water to Abeokuta was ... water related diseases as a result of the consumption of drinking water ... who relied on water from alternative sources subjected the water to treatment before ...

  14. The influence of Greenland melt water on climate during past and future warm periods: a model study

    Science.gov (United States)

    Blaschek, Michael; Bakker, Pepijn; Renssen, Hans

    2013-04-01

    "Can past climates teach us something about the future?" Under this general question of interest to most palaeoclimate-modeller we specified it more to "Can past changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) related to melt water from the Greenland Ice Sheet (GIS) teach us something about future changes in the AMOC forced by predicted partial melting of the GIS?" To address this question, we developed a series of sensitivity experiments with the global atmosphere-ocean-sea-ice model LOVECLIM to better understand the relationship between the strength of the Atlantic Meridional Overturning Circulation (AMOC) and Greenland Ice Sheet (GIS) melt over the last and present interglacials (the Eemian and the Holocene, respectively) and put these into perspective of future greenhouse gas emission scenarios. In terms of radiative forcing, future emission scenarios are different from past orbitally-forced warm periods, as past insolation varied per season and per latitude, whereas radiative forcing due to future greenhouse gas emissions has no seasonal component (i.e. it is an annual forcing) and shows little variation per latitude. However, the two can be compared when we consider the radiative forcing regimes of the different considered warm climates, by focusing on the energy that is potentially available from radiative forcing to melt the GIS. In a similar approach, Swingedouw et al. (2009) have shown in simulations with an AOGCM that the AMOC sensitivity relates non-linear to freshwater input and that under Last Glacial Maximum (LGM) conditions the climate is more sensitive compared to warmer climates. They conclude that different climatic conditions share similar patterns in response and that past climates are useful for models to evaluate their abilities in reproducing past events. The authors encourage further model sensitivity testing to gain a better understanding of this highly important question. In order to test this approach we

  15. A first screening and risk assessment of pharmaceuticals and additives in personal care products in waste water, sludge, recipient water and sediment from Faroe Islands, Iceland and Greenland.

    Science.gov (United States)

    Huber, Sandra; Remberger, Mikael; Kaj, Lennart; Schlabach, Martin; Jörundsdóttir, Hrönn Ó; Vester, Jette; Arnórsson, Mímir; Mortensen, Inge; Schwartson, Richard; Dam, Maria

    2016-08-15

    A screening of a broad range of pharmaceuticals and additives in personal care products (PPCPs) in sub-arctic locations of the Faroe Islands (FO), Iceland (IS) and Greenland (GL) was conducted. In total 36 pharmaceuticals including some metabolites, and seven additives in personal care products were investigated in influent and effluent waters as well as sludge of waste water treatment plants (WWTPs) and in water and sediment of recipients. Concentrations and distribution patterns for PPCPs discharged via sewage lines (SLs) to the marine environment were assessed. Of the 36 pharmaceuticals or metabolites analysed 33 were found close to or above the limit of detection (LOD) in all or a part of the samples. All of the seven investigated additives in personal care products were detected above the LOD. Some of the analysed PPCPs occurred in every or almost every sample. Among these were diclofenac, ibuprofen, lidocaine, naproxen, metformin, citalopram, venlafaxine, amiloride, furosemide, metoprolol, sodium dodecyl sulphate (SDS) and cetrimonium salt (ATAC-C16). Additionally, the study encompasses ecotoxicological risk assessment of 2/3 of the analysed PPCPs in recipient and diluted effluent waters. For candesartan only a small margin to levels with inacceptable risks was observed in diluted effluent waters at two locations (FO). Chronical risks for aquatic organisms staying and/or living around WWTP effluent pipe-outlets were indicated for 17β-estradiol and estriol in the three countries. Additives in PCPs were found to pose the largest risk to the aquatic environment. The surfactants CAPB and ATAC-C16 were found in concentrations resulting in risk factors up to 375 for CAPB and 165 for ATAC-C16 in recipients for diluted effluents from Iggia, Nuuk (GL) and Torshavn (FO) respectively. These results demonstrates a potentially high ecological risk stemming from discharge of surfactants as used in household and industrial detergents as well as additives in personal care

  16. Differences in plankton community structure and carbon cycling along a climate gradient from the Greenland Ice Sheet to offshore waters

    DEFF Research Database (Denmark)

    Arendt, K.E.; Nielsen, Torkel Gissel; Rysgaard, S.

    . Protozooplankton accounts for 20-38% of the carbon turnover in the offshore and inland areas. However, protozooplankton like copepods has low ability to turn over the primary production close to the Ice Sheet. Increased run of from the Greenland Ice Sheet due to global warming could displace the existing climate...

  17. A cascade of warming impacts brings bluefin tuna to Greenland waters

    DEFF Research Database (Denmark)

    MacKenzie, Brian; Payne, Mark; Boje, Jesper;

    since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species into the region. We conclude that a cascade of climate change impacts......, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9-11o C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed to a warming trend...

  18. The impact of calving front retreat on Jakobshavn Isbræ, West Greenland , using a 3D thermodynamically coupled numerical model

    Science.gov (United States)

    Bondzio, J. H.; Seroussi, H. L.; Morlighem, M.; Kleiner, T.; Rückamp, M.; Larour, E. Y.; Humbert, A.

    2016-12-01

    Jakobshavn Isbræ is a major marine terminating outlet glacier of the Greenland Ice Sheet. Since the breakup of its floating ice tongue in the late 1990's, the glacier has been thinning, accelerating and its calving front has been retreating by about 20 km. It is currently a major contributor to global sea level rise. Understanding the processes involved in and driving these changes is important to improve the predictive skills of numerical models and improve estimates of future dynamic ice discharge of the Greenland Ice Sheet. However, the limited amount of observations when the glacier underwent these strong changes does not allow us to fully understand the interplay and significance of the processes involved. Numerical modelling can be used to improve our understanding, but ice flow model studies so far suffered from lacking technical capabilities, poorly constrained input data sets and insufficient computational resources. Here, we use the Ice Sheet System Model (ISSM) to perform, for the first time, a high-resolution, 3D thermodynamically coupled model study of Jakobshavn Isbræ with a dynamically evolving ice front. We perform several sensitivity studies by analyzing the influence of submarine melt, calving and thermal regime on the glacier's thermodynamics to determine the processes that control the response of the glacier to climate change. We find that increased submarine melt significantly contributed to the initial speed-up of the glacier, but that today's flow regime is almost entirely controlled by it's calving front position, which agrees well with observations. The glacier's acceleration causes a substantial increase in internal and basal friction, which increases subglacial melt rates. Sustained higher submarine discharge might increase undercutting of the calving front through melt, leading to higher calving rates even in case of a glacier slow down, creating a potential positive feedback.

  19. Oxygen isotope ratios in the shell of Mytilus edulis: archives of glacier meltwater in Greenland?

    Science.gov (United States)

    Versteegh, E. A. A.; Blicher, M. E.; Mortensen, J.; Rysgaard, S.; Als, T. D.; Wanamaker, A. D., Jr.

    2012-09-01

    Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthåbsfjord (West Greenland), where glacier meltwater causes seasonal excursions with lower oxygen isotope water (δ18Ow) values and salinity. The blue mussel (Mytilus edulis) potentially records these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient seawater. As M. edulis shells are known to occur in raised shorelines and kitchen middens from previous Holocene warm periods, this species may be ideal in reconstructing past meltwater dynamics. We investigate its potential as a palaeo-meltwater proxy. First, we confirmed that M. edulis shell calcite oxygen isotope (δ18Oc) values are in equilibrium with ambient water and generally reflect meltwater conditions. Subsequently we investigated if this species recorded the full range of δ18Ow values occurring during the years 2007 to 2010. Results show that δ18Ow values were not recorded at very low salinities (future research will expand on the geographical and temporal range of the shell measurements by sampling mussels in other fjords in Greenland along a south-north gradient, and by sampling shells from raised shorelines and kitchen middens from prehistoric settlements in Greenland.

  20. High-resolution passive sampling of dissolved methane in the water column of lakes in Greenland

    Science.gov (United States)

    Goldman, A. E.; Cadieux, S. B.; White, J. R.; Pratt, L. M.

    2013-12-01

    Arctic lakes are important participants in the global carbon cycle, releasing methane in a warming climate and contributing to a positive feedback to climate change. In order to yield detailed methane budgets and understand the implications of warming on methane dynamics, high-resolution profiles revealing methane behavior within the water column need to be obtained. Single day sampling using disruptive techniques has the potential to result in biases. In order to obtain high-resolution, undisturbed profiles of methane concentration and isotopic composition, this study evaluates a passive sampling method over a multi-day equilibration period. Selected for this study were two small lakes (Gatos Research Methane Carbon Isotope Analyzer. PDB sampling and pump sampling resulted in statistically similar concentrations (R2=0.89), ranging from 0.85 to 135 uM from PDB and 0.74 to 143 uM from pump sampling. In anoxic waters of the lake, where concentrations were high enough to yield robust isotopic results on the LGR MCIA, δ13C were also similar between the two methods, yielding -73‰ from PDB and -74‰ from pump sampling. Further investigation will produce results for a second lake and methane carbon and hydrogen isotopic composition for both lakes. Preliminary results for this passive sampling method are promising. We envision the use of this technique in future studies of dissolved methane and expect that it will provide a more finely resolved vertical profile, allowing for a more complete understanding of lacustrine methane dynamics.

  1. The Chemical Compositions of Thermal Waters at Ciarinem and Cilayu, Pameungpeuk, West Java - Indonesia

    Directory of Open Access Journals (Sweden)

    N.R. Herdianita

    2008-03-01

    Full Text Available Thermal waters at Ciarinem and Cilayu, Pameungpeuk, West Java, Indonesia have different characteristics: Ciarinem water is a steam heated sulfate type and occurs as hot springs, whereas Cilayu water discharges as hot pools and is a chloride water type. Their chemical compositions indicate that the thermal waters are outflows of a volcanic–magmatic associated geothermal system. The solute geothermometers calculate that the subsurface reservoir temperatures range from 150o to 200ºC.

  2. Water Accounting Plus for sustainable water management in the Volta river basin, West Africa

    Science.gov (United States)

    Dembélé, Moctar; Schaefli, Bettina; Mariéthoz, Grégroire; Ceperley, Natalie; Zwart, Sander J.

    2017-04-01

    Water Accounting Plus (WA+) is a standard framework that provides estimates of manageable and unmanageable water flows, stocks, consumption among users, and interactions with land use. The water balance terms are estimated based on remotely sensed data from online open access databases. The main difference with other methods is the use of spatiotemporal data, limiting the errors due to the use of static data. So far, no studies have incorporated climate change scenarios in the WA+ framework to assess future water resources, which would be desirable for developing mitigation and adaptation policies. Moreover WA+ has been implemented using remote sensing data while hydrological models data can also be used as inputs for projections on the future water accounts. This study aims to address the above challenges by providing quantified information on the current and projected state of the Volta basin water resources through the WA+ framework. The transboundary Volta basin in West Africa is vulnerable to floods and droughts that damage properties and take lives. Residents are dependent on subsistence agriculture, mainly rainfed, which is sensitive to changes and variation in the climate. Spatially, rainfall shows high spatiotemporal variability with a south-north gradient of increasing aridity. As in many basins in semi-arid environments, most of the rainfall in the Volta basin returns to the atmosphere. The competition for scarce water resources will increase in the near future due to the combined effects of urbanization, economic development, and rapid population growth. Moreover, upstream and downstream countries do not agree on their national priorities regarding the use of water and this brings tensions among them. Burkina Faso increasingly builds small and medium reservoirs for small-scale irrigation, while Ghana seeks to increase electricity production. Information on current and future water resources and uses is thus fundamental for water actors. The adopted

  3. The Northeast Greenland Sirius Water Polynya dynamics and variability inferred from satellite imagery

    DEFF Research Database (Denmark)

    Pedersen, Jørn Bjarke Torp; Kaufmann, Laura Hauch; Kroon, Aart

    2010-01-01

    ’, and examines its spatial and temporal dynamics by analysis of recent satellite imagery, modelled meteorological data and historical data covering the last decade. The dominating mechanisms to form and sustain the polynya are inferred and the persistence and inter-annual variability of the phenomenon...... and summer regimes in the seasonal evolution of the polynya. During the winter regime, both the size of and the ice cover within the polynya varies significantly on a temporal and spatial scale. Intermittent wind-driven openings of the polynya alternate with periods of increasing ice cover. Some of the most...... persistent areas of open water in the polynya coincide with locations where significant concentrations of spring and summer settlements from the Thule Inuit culture (AD 1400-1850) are observed, indicating a connection between the presence of the polynya and the Thule Inuit living in the area in prehistoric...

  4. The Northeast Greenland Sirius Water Polynya dynamics and variability inferred from satellite imagery

    DEFF Research Database (Denmark)

    Pedersen, Jørn Bjarke Torp; Kaufmann, Laura Hauch; Kroon, Aart

    2010-01-01

    ’, and examines its spatial and temporal dynamics by analysis of recent satellite imagery, modelled meteorological data and historical data covering the last decade. The dominating mechanisms to form and sustain the polynya are inferred and the persistence and inter-annual variability of the phenomenon...... are estimated. The polynya formation is predominantly governed by mechanical forcing caused by northerly gales, and it is classified as a wind-driven shelf water polynya. A marked seasonal difference in the surface wind field, together with the obvious seasonal cycle in insolation, creates distinct winter...... and summer regimes in the seasonal evolution of the polynya. During the winter regime, both the size of and the ice cover within the polynya varies significantly on a temporal and spatial scale. Intermittent wind-driven openings of the polynya alternate with periods of increasing ice cover. Some of the most...

  5. Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model

    Directory of Open Access Journals (Sweden)

    R. Marsh

    2010-07-01

    Full Text Available In a sensitivity experiment, an eddy-permitting ocean general circulation model is forced with realistic freshwater fluxes from the Greenland Ice Sheet, averaged for the period 1991–2000. The fluxes are obtained with a mass balance model for the ice sheet, forced with the ERA-40 reanalysis dataset. The freshwater flux is distributed around Greenland as an additional term in prescribed runoff, representing seasonal melting of the ice sheet and a fixed year-round iceberg calving flux, for 8.5 model years. By adding Greenland freshwater fluxes with realistic geographical distribution and seasonality, the experiment is designed to investigate the oceanic response to a sudden and spatially/temporally uniform amplification of ice sheet melting and discharge, rather than localized or gradual changes in freshwater flux. The impacts on regional hydrography and circulation are investigated by comparing the sensitivity experiment to a control experiment, without additional fluxes. By the end of the sensitivity experiment, the majority of additional fresh water has accumulated in Baffin Bay, and only a small fraction has reached the interior of the Labrador Sea, where winter mixed layer depth is sensitive to small changes in salinity. As a consequence, the impact on large-scale circulation is very slight. An indirect impact of strong freshening off the west coast of Greenland is a small anti-cyclonic component to the circulation around Greenland, which opposes the wind-driven cyclonic circulation and reduces net southward flow through the Canadian Archipelago by ~10%. Implications for the post-2000 acceleration of Greenland mass loss are discussed.

  6. Moulin density controls drainage development beneath the Greenland ice sheet

    Science.gov (United States)

    Banwell, Alison; Hewitt, Ian; Willis, Ian; Arnold, Neil

    2016-12-01

    Uncertainty remains about how the surface hydrology of the Greenland ice sheet influences its subglacial drainage system, affecting basal water pressures and ice velocities, particularly over intraseasonal and interseasonal timescales. Here we apply a high spatial (200 m) and temporal (1 h) resolution subglacial hydrological model to a marginal (extending 25 km inland), land-terminating, 200 km2 domain in the Paakitsoq region, West Greenland. The model is based on that by Hewitt (2013) but adapted for use with both real topographic boundary conditions and calibrated modeled water inputs. The inputs consist of moulin hydrographs, calculated by a surface routing and lake-filling/draining model, which is forced with distributed runoff from a surface energy-balance model. Results suggest that the areal density of lake-bottom moulins and their timing of opening during the melt season strongly affects subglacial drainage system development. A higher moulin density causes an earlier onset of subglacial channelization (i.e., water transport through channels rather than the distributed sheet), which becomes relatively widespread across the bed, whereas a lower moulin density results in a later onset of channelization that becomes less widespread across the bed. In turn, moulin density has a strong control on spatial and temporal variations in subglacial water pressures, which will influence basal sliding rates, and thus ice motion. The density of active surface-to-bed connections should be considered alongside surface melt intensity and extent in future predictions of the ice sheet's dynamics.

  7. Success and failure of reindeer herding in Greenland

    Directory of Open Access Journals (Sweden)

    Christine Cuyler

    1999-04-01

    Full Text Available Animal husbandry is a recent innovation in Greenland, specifically reindeer husbandry is less than 50 years old. Reindeer husbandry was first established in mid-west Greenland and later in southern Greenland. The Greenland hunter tradition and culture is, however, still dominant in many communities. During the 1980s and 1990s, the incompatibility of these two traditions resulted in the failure of reindeer husbandry in mid-west Greenland. There were neither herding nor seasonal herd movements. Animals remained year round on the winter range, which was destroyed as lichens were trampled every summer. Without seasonal herd movements both sustainable range use and control of the herd were lost. Today, there are just two semi-domestic reindeer herds left, and both are in southern Greenland. One herd is commercially successful, and the other is under development. In mid-west Greenland, semi-domestic reindeer husbandry officially ended in 1998, and a hunt was initiated to remove the remaining population. Possibly, by the year 2000 any animals left in this region will be considered wild caribou.

  8. The peopling of Greenland

    DEFF Research Database (Denmark)

    Pereira, Vania; Tomas Mas, Carmen; Sanchez, Juan J

    2015-01-01

    The peopling of Greenland has a complex history shaped by population migrations, isolation and genetic drift. The Greenlanders present a genetic heritage with components of European and Inuit groups; previous studies using uniparentally inherited markers in Greenlanders have reported evidence of ...

  9. Water masses and general hydrography along the west coast of India during early March

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Varkey, M.J.; Das, V.K.; Gouveia, A.D.

    Structure of water masses along the west coast of India from Bombay to Trivandrum has been studied through vertical sections of temperature, salinity and density during 3-17 March 1977. The Arabian Sea high salinity water spreads south as a core...

  10. Regional vegetation water effects on satellite soil moisture estimations for West Africa

    NARCIS (Netherlands)

    Friesen, J.C.

    2008-01-01

    Soil moisture information is a vital parameter for water resources planning and food production. In particular for West Africa, where income largely depends on rainfed agriculture, reliable information on available soil water is required for modeling and prediction. Over large areas and, specificall

  11. The Influence of Greenland melt water on the temporal and spatial response of the Holocene Thermal Maximum in the Nordic Seas: a modelling study

    Science.gov (United States)

    Blaschek, M.; Renssen, H.

    2012-04-01

    In the early-to-mid Holocene a period of relatively warm climate, known as the Holocene thermal maximum (HTM, 11-5 kyr BP), has been associated with the orbitally-forced northern hemisphere summer insolation maximum at approximately 10 kyr BP. Although the HTM is orbitally forced, the spatial and temporal response of its climate signature is diverse. At 9 kyr BP remnants of glacial ice sheets, most importantly the Laurentide Ice Sheet (LIS), modified the climate of the North Atlantic region by freshening the ocean surface through melt water discharge, and by altering the surface albedo and topography. A previous climate modelling study (Renssen et al. 2009) has shown that the LIS delayed the HTM in the Nordic Seas by up to 3000 years. We extend this approach by introducing another source of melt water in the early Holocene, the Greenland Ice Sheet (GIS). The GIS was likely up to 25% larger (at 9 kyr BP) in volume than at present-day (Vinther et al. 2009, Peltier, 2004) and is therefore potentially an important regional contributor to climate change in the Nordic Seas. We present here simulations performed with the LOVECLIM1.2 global ocean-atmosphere-vegetation model. These simulations seek to highlight the spatial and temporal impact of GIS melting on the early Holocene climate, in terms of sea surface temperature (SST). Several sensitivity experiments with fixed 9 kyr BP forcings were performed for different Greenland melt water fluxes to test model and climate sensitivity. These melt water fluxes range from 0 to 52 mSv. The sensitivity experiments show that GIS melting considerably influences sea surface conditions around the southern part of Greenland, and that 13 to 26 mSv of GIS melting, in a combination with the LIS background melting, agrees better in that region with proxy-based SST reconstructions. In a further step, transient simulations exhibit the long term (9 to 0 kyr BP) impact of GIS melting on the development of the Holocene climate. Transient

  12. Weather Test Reference Year of Greenland

    DEFF Research Database (Denmark)

    Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

    2005-01-01

    The building code of Greenland from 1982 is to be revised in the coming years fulfilling the increased demand of more energy efficient buildings. To establish appropriate levels of energy consumption for heating the weather conditions have to be analyzed. The purpose of this paper is to describe...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...

  13. Weather Test Reference Year of Greenland

    DEFF Research Database (Denmark)

    Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

    2005-01-01

    The building code of Greenland from 1982 is to be revised in the coming years fulfilling the increased demand of more energy efficient buildings. To establish appropriate levels of energy consumption for heating the weather conditions have to be analyzed. The purpose of this paper is to describe...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...

  14. The influence of winter and summer atmospheric circulation on the variability of temperature and sea ice around Greenland

    Directory of Open Access Journals (Sweden)

    Masayo Ogi

    2016-10-01

    Full Text Available Most peripheral seas of the Arctic Ocean have seen a pronounced rise in sea surface temperatures in the past century, and this signature of Arctic amplification in proximity to the land suggests that the observed marine and terrestrial changes might be connected to each other. Using in situ observations of temperature from nine coastal meteorological stations around Greenland (GrSTs and remotely sensed fields of sea ice extent (SIE, we examine the interannual variations of surface air temperature (T2m and sea level pressure (SLP anomalies associated with the GrSTs and SIEs surrounding Greenland, specifically within Baffin Bay, the Greenland Sea and Kara-Barents Seas. During winter, the interannual variation in T2m and SLP of the west and south coasts of GrSTs and the Baffin Bay SIE are different from that of the east coast of GrSTs and the SIEs in the Greenland Sea and Kara-Barents Seas. The GrSTs on the west and south coasts of Greenland and the Baffin Bay SIE are associated with the T2m anomalies over Baffin Bay and Davis Strait. The winter SLP patterns associated with these GrSTs and SIEs show positive anomalies over the Arctic and negative anomalies over the North Atlantic with a large-scale atmospheric circulation such as the winter NAO. On the contrary, the east coast of GrSTs and the SIEs in the Greenland Sea and Kara-Barents Seas are correlated with the T2m anomalies over the Greenland Sea and Barents Sea. The surface wind pattern associated with the SIEs in the Greenland Sea and Kara-Barents Seas has a cyclonic circulation in the Greenland Sea and Barents Sea. At the local scale the cyclonic circulation could induce negative SIE anomalies and contribute to increasing open water in the Greenland Sea and Barents Sea. The effect of the loss of sea ice and the heat from the open ocean warming to the atmosphere may influence the GrSTs in the east coast of Greenland. As a result, the T2m pattern associated with the GrSTs in the east coast of

  15. 76 FR 30936 - West Maui Pumped Storage Water Supply, LLC; Notice of Preliminary Permit Application Accepted for...

    Science.gov (United States)

    2011-05-27

    ... Energy Regulatory Commission West Maui Pumped Storage Water Supply, LLC; Notice of Preliminary Permit... April 1, 2011, West Maui Pumped Storage Water Supply, LLC, filed an application for a preliminary permit... supply project effluent water to an existing irrigation system; (5) a powerhouse with two...

  16. The North Water Polynya and Velocity, Calving Front and Mass Change in Surrounding Glaciers in Greenland and Canada Over the Last 30 Years

    Science.gov (United States)

    Edwards, L.

    2015-12-01

    Major uncertainties surround future estimates of sea level rise attributable to mass loss from Greenland and the surrounding ice caps in Canada. Understanding changes across these regions is vital as their glaciers have experienced dramatic changes in recent times. Attention has focused on the periphery of these regions where land ice meets the ocean and where ice acceleration, thinning and increased calving have been observed. Polynyas are areas of open water within sea ice which remain unfrozen for much of the year. They vary significantly in size (~3 km2 to > ~85,000 km2 in the Arctic), recurrence rates and duration. Despite their relatively small size, polynyas strongly impact regional oceanography and play a vital role in heat and moisture exchange between the polar oceans and atmosphere. Where polynyas are present adjacent to tidewater glaciers their influence on ocean circulation and water temperatures has the potential to play a major part in controlling subsurface ice melt rates by impacting on the water masses reaching the calving front. They also have the potential to influence air masses reaching nearby glaciers and ice caps by creating a maritime climate which may impact on the glaciers' accumulation and surface melt and hence their thickness and mass balance. Polynya presence and size also have implications for sea ice extent and therefore may influence the buttressing effect on neighbouring tidewater glaciers. The work presented uses remote sensing and mass balance model data to study changes in the North Water polynya (extent, ice concentration, duration) and neighbouring glaciers and ice caps (velocities, calving front positions and mass balance) in Canada and Greenland over a period of approximately 30 years from the mid-1980s through to 2015.

  17. The West Melilla cold water coral mounds, Eastern Alboran Sea: Morphological characterization and environmental context

    Science.gov (United States)

    Lo Iacono, Claudio; Gràcia, Eulàlia; Ranero, Cesar R.; Emelianov, Mikhail; Huvenne, Veerle A. I.; Bartolomé, Rafael; Booth-Rea, Guillermo; Prades, Javier; Ambroso, Stefano; Dominguez, Carlos; Grinyó, Jordi; Rubio, Eduardo; Torrent, Josep

    2014-01-01

    A new mound field, the West Melilla mounds, interpreted as being cold-water coral mounds, has been recently unveiled along the upper slope of the Mediterranean Moroccan continental margin, a few kilometers west of the Cape Tres Forcas. This study is based on the integration of high-resolution geophysical data (swath bathymetry, parametric sub-bottom profiler), CTD casts, Acoustic Doppler Current Profiler (ADCP), ROV video and seafloor sampling, acquired during the TOPOMED GASSIS (2011) and MELCOR (2012) cruises. Up to 103 mounds organized in two main clusters have been recognized in a depth range of 299-590 m, displaying a high density of 5 mounds/km2. Mounds, 1-48 m high above the surrounding seafloor and on average 260 m wide, are actually buried by a 1-12 m thick fine-grained sediment blanket. Seismic data suggest that the West Melilla mounds grew throughout the Early Pleistocene-Holocene, settling on erosive unconformities and mass movement deposits. During the last glacial-interglacial transition, the West Melilla mounds may have suffered a drastic change of the local sedimentary regime during the late Holocene and, unable to stand increasing depositional rates, were progressively buried. At the present day, temperature and salinity values on the West Melilla mounds suggest a plausible oceanographic setting, suitable for live CWCs. Nonetheless, more data is required to groundtruth the West Melilla mounds and better constrain the interplay of sedimentary and oceanographic factors during the evolution of the West Melilla mounds.

  18. Recent changes in north-west Greenland climate documented by NEEM shallow ice core data and simulations, and implications for past-temperature reconstructions

    Science.gov (United States)

    Masson-Delmotte, V.; Steen-Larsen, H. C.; Ortega, P.; Swingedouw, D.; Popp, T.; Vinther, B. M.; Oerter, H.; Sveinbjornsdottir, A. E.; Gudlaugsdottir, H.; Box, J. E.; Falourd, S.; Fettweis, X.; Gallée, H.; Garnier, E.; Gkinis, V.; Jouzel, J.; Landais, A.; Minster, B.; Paradis, N.; Orsi, A.; Risi, C.; Werner, M.; White, J. W. C.

    2015-08-01

    Combined records of snow accumulation rate, δ18O and deuterium excess were produced from several shallow ice cores and snow pits at NEEM (North Greenland Eemian Ice Drilling), covering the period from 1724 to 2007. They are used to investigate recent climate variability and characterise the isotope-temperature relationship. We find that NEEM records are only weakly affected by inter-annual changes in the North Atlantic Oscillation. Decadal δ18O and accumulation variability is related to North Atlantic sea surface temperature and is enhanced at the beginning of the 19th century. No long-term trend is observed in the accumulation record. By contrast, NEEM δ18O shows multidecadal increasing trends in the late 19th century and since the 1980s. The strongest annual positive δ18O values are recorded at NEEM in 1928 and 2010, while maximum accumulation occurs in 1933. The last decade is the most enriched in δ18O (warmest), while the 11-year periods with the strongest depletion (coldest) are depicted at NEEM in 1815-1825 and 1836-1846, which are also the driest 11-year periods. The NEEM accumulation and δ18O records are strongly correlated with outputs from atmospheric models, nudged to atmospheric reanalyses. Best performance is observed for ERA reanalyses. Gridded temperature reconstructions, instrumental data and model outputs at NEEM are used to estimate the multidecadal accumulation-temperature and δ18O-temperature relationships for the strong warming period in 1979-2007. The accumulation sensitivity to temperature is estimated at 11 ± 2 % °C-1 and the δ18O-temperature slope at 1.1 ± 0.2 ‰ °C-1, about twice as large as previously used to estimate last interglacial temperature change from the bottom part of the NEEM deep ice core.

  19. Sedimentary evolution models of Lower Triassic deep-water carbonate rocks of west Qinling Mts.

    Institute of Scientific and Technical Information of China (English)

    晋慧娟; 李育慈

    1995-01-01

    Based on the study of Lower Triassic deep-water carbonate rock sequence of west Qinling Mts . deep-water carbonate rock sequence is divided into lower fine-grain euxinic deposits of a carbonate gentle slope type and upper bathyal and abyssal sediments of carbonate steep slope type. The upper member is emphatically analysed and synthesized into five fades associations. They comprise four fining- and thinning-upward megacycles, each of them representing a sedimentary column which accumulated after a tensional fault subsidence event, which recorded a whole rifting process of west Qinling ocean trough during Lower Triassic.

  20. GIS-Based Evaluation of Water Quality Index of Ground Water Resources in West Bokaro Coalfield, India

    OpenAIRE

    Ashwani Kumar Tiwari; Prasoon Kumar Singh; Mukesh Kumar Mahato

    2014-01-01

    Water Quality Index (WQI), a technique of rating water quality, is an effective tool to assess quality and ensure sustainable safe use of water for drinking. The present work is aimed to assess the groundwater quality of West Bokaro coalfield region for knowing the suitability of drinking purpose by calculating the WQI and using Geographical Information System (GIS) techniques. Thirty three groundwater samples were collected from dug wells during post-monsoon, 2012 for comprehensive physico-c...

  1. Walrus Movements in Smith Sound: A Canada–Greenland Shared Stock

    DEFF Research Database (Denmark)

    Heide-Jørgensen, Mads Peter; Flora, Janne; Andersen, Astrid Oberborbeck

    2017-01-01

    Fiord, Buchanan Bay, and Flagler Bay (west of Kane Basin) and Talbot Inlet farther south, and on the southern coast, Craig Harbour. This distribution of tagged walruses is consistent with prior understanding of walrus movements in summer. In addition, however, nine tracks of these tagged animals entered...... moving between Greenland and Canada also used offshore areas in Smith Sound. This study demonstrates that the walrus population that winters along the northwestern coast of Greenland is shared more widely in Canada than previously thought and should be managed accordingly....... coast in June – July (average 14th June), simultaneously with the disappearance of sea ice from these areas. Most of them moved to Canadian waters in western Smith Sound. The most frequently used summering grounds were along the coasts of Ellesmere Island: on the eastern coast, the area around Alexandra...

  2. Stable oxygen isotope variability in two contrasting glacier river catchments in Greenland

    DEFF Research Database (Denmark)

    Yde, Jacob C.; Knudsen, Niels T.; Steffensen, Jørgen P.;

    2016-01-01

    subglacial drainage network in the upper part of the glacier. At the Kuannersuit Glacier river on the island Qeqertarsuaq in west Greenland, the δ18O characteristics were examined after the major 1995-1998 glacier surge event. The mean annual δ18O was -19.47±0.55 ‰. Despite large spatial variations in the δ......18O values of glacier ice on the newly formed glacier tongue, there were no diurnal oscillations in the bulk meltwater emanating from the glacier in the post-surge years. This is likely a consequence of a tortuous subglacial drainage system consisting of linked cavities, which formed during the surge......Analysis of stable oxygen isotope (δ18O) characteristics is a useful tool to investigate water provenance in glacier river systems. In order to attain knowledge on the diversity of δ18O variations in Greenlandic rivers, we examined two contrasting glacierised catchments disconnected from...

  3. Oxygen isotope ratios in the shell of Mytilus edulis: Archives of glacier meltwater in Greenland?

    DEFF Research Database (Denmark)

    Versteegh, E.A.A.; Blicher, M.E.; Mortensen, J.

    2012-01-01

    predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthabsfjord (West Greenland), where glacier meltwater causes seasonal excursions with lower oxygen isotope water (delta O-18(w)) values and salinity. The blue mussel (Mytilus edulis) potentially records......Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models...... these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient seawater. As M. edulis shells are known to occur in raised shorelines and archaeological shell middens from previous Holocene warm periods, this species may be ideal in reconstructing past meltwater dynamics. We...

  4. Oxygen isotope ratios in the shell of Mytilus edulis: archives of glacier meltwater in Greenland?

    DEFF Research Database (Denmark)

    Versteegh, E. A. A.; Blicher, Martin E.; Mortensen, J.

    2012-01-01

    predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthåbsfjord (West Greenland), where glacier meltwater causes seasonal excursions with lower oxygen isotope water (δ18Ow) values and salinity. The blue mussel (Mytilus edulis) potentially records......Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models...... these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient seawater. As M. edulis shells are known to occur in raised shorelines and kitchen middens from previous Holocene warm periods, this species may be ideal in reconstructing past meltwater dynamics. We investigate...

  5. Physical activity in Greenland - a methodological perspective

    DEFF Research Database (Denmark)

    Dahl-Petersen, Inger

    Title: Physical activity in Greenland - a methodical perspective Inger Dahl-Petersen, National Institute of Public Health, Copenhagen, Denmark Purpose:   The present study is the first population-based study in Greenland with information on physical activity using The International Physical...... Participants in a cross-sectional population survey representative of towns and villages in West Greenland completed an interviewer-administered questionnaire about their physical activity. The long version of The International Physical Activity Questionnaire (IPAQ) was used to measure time spent on physical.......001). Less energy was used in leisure time among women living in a village (Pphysical activity in leisure time, home, work and transportation and provide information on both time and energy...

  6. Persistent organic pollutants and methoxylated polybrominated diphenyl ethers in different tissues of white-tailed eagles (Haliaeetus albicilla) from West Greenland

    DEFF Research Database (Denmark)

    Jaspers, V L B; Sonne, C; Soler-Rodriguez, F

    2013-01-01

    We investigated polychlorinated biphenyls (PCBs), organochlorine pesticides (e.g. dichlorodiphenyltrichloroethane (DDT)), polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO-PBDEs), in six matrices (muscle, liver, kidney, adipose, blood, preen oil) of 17 white-tailed eagles from West...... > 5 years) displayed PCB levels up to 1500 μg/g lw in liver, which is the highest concentration ever reported in Arctic wildlife. Muscle generally contained the highest median levels, while adipose tissue displayed the lowest median levels on a lipid basis. No significant differences were found among...

  7. West Antarctic Mantle Plume Hypothesis and Basal Water Generation

    Science.gov (United States)

    Ivins, Erik; Seroussi, Helene; Wiens, Doug; Bondzio, Johannes

    2017-04-01

    The hypothesis of a deep mantle plume that manifests Pliocene and Quaternary volcanism and present-day seismicity in West Antarctica has been speculated for more than 30 years. Recent seismic images support the plume hypothesis as the cause of Marie Byrd Land (MBL) volcanism and geophysical structure [ Lloyd et al., 2015; Ramirez et al., 2016]. Mantle plumes can more that double the geothermal heat flux, qGHF, above nominal continental values at their axial peak position and raise qGHF in the surrounding plume head to 60 mW/m2 or higher. Unfortunately, there is a dearth of in-situ basal ice sheet data that sample the heat flux. Consequently, we examine a realistic distribution of heat flux associated with a late-Cenozoic mantle plume in West Antarctica and explore its impact on thermal and melt conditions near the ice sheet base. The solid Earth model assumes a parameterized deep mantle plume and head. The 3-D ice flow model includes an enthalpy framework and full-Stokes stress balance. Both the putative plume location and extent are uncertain. Therefore, we perform broadly scoped experiments to characterize plume related basal conditions. The experiments show that mantle plumes have an important local impact on the ice sheet, with basal melting rates reaching several centimeters per year directly above the hotspot. The downstream active lake system of Whillans Ice Stream suggests a rift-related source of anomalous mantle heat. However, the lack of lake and stream activity in MBL suggests a relatively weak plume: one that delivers less flux by 35% below the heat flux to the crustal surface at the site of the Yellowstone hotspot [e.g., DeNosaquo et al., 2009], with peak value no higher than about 145 mW/m2.

  8. Exploring geophysical processes influencing U.S. West Coast precipitation and water supply

    Science.gov (United States)

    Ralph, F.M.; Prather, K.; Cayan, D.

    2011-01-01

    CalWater Science Workshop; La Jolla, California, 8-10 June 2011 CalWater is a multiyear, multiagency research project with two primary research themes: the effects of changing climate on atmospheric rivers (ARs) and associated extreme events, and the potential role of aerosols in modulating cloud properties and precipitation, especially regarding orographic precipitation and water supply. Advances made in CalWater have implications for both water supply and flood control in California and other West Coast areas, both in the near term and in a changing climate.

  9. Bergy Bit and Melt Water Trajectories in Godthåbsfjord (SW Greenland Observed by the Expendable Ice Tracker

    Directory of Open Access Journals (Sweden)

    Daniel F. Carlson

    2017-08-01

    Full Text Available Icebergs and bergy bits makes up a significant component of the total freshwater flux from the Greenland Ice Sheet to the ocean. Observations of iceberg trajectories are biased toward larger icebergs and, as a result, the drift characteristics of smaller icebergs and bergy bits are poorly understood. In an attempt to fill this critical knowledge gap, we developed the open-source EXpendable Ice TrackEr (EXITE. EXITE is a low-cost, satellite-tracked GPS beacon capable of high-resolution temporal measurements over extended deployment periods (30 days or more. Furthermore, EXITE can transform to a surface drifter when its host iceberg capsizes or fragments. Here we describe basic construction of an EXITE beacon and present results from a deployment in Godthåbsfjord (SW Greenland in August 2016. Overall, EXITE trajectories show out-fjord surface transport, in agreement with a simple estuarine circulation paradigm. However, eddies and abrupt wind-driven reversals reveal complex surface transport pathways at time scales of hours to days.

  10. Determination of Water Sensitivity Index in EstakoWest and Esan Central, Nigeria

    Directory of Open Access Journals (Sweden)

    Philipa O. Idogho

    2014-07-01

    Full Text Available As world population and industrial-agricultural outputs have increased, the use of water has accelerated. This development leads to extreme difficulty to provide sufficient safe drinking water in Etasko-West and Esan Central. Water sensitivity was measured in six major towns in Etasko-West and Esan Central. Water Measuring Indicators such as Water Poverty Index-Real Time (WPIr, Water Factor Value (WFV and Access-Demand Factor (γ were applied to generate water sensitivity iterations. The outputs of these iterations show that Irrua has the fairest water supply and distribution with WPIr, WFA and γ index value of 0.22; 0.77 and 0.76, while Auchi and Ewu experience acute water shortage with the following index values: WPIr-0.43, 0.39; WFV-0.06, 0.16; and γ-0.64, 0.6 respectively. Results of One-Sample Test and Paired Sample Statistics show that the proportion of monthly income spent on portable water is significant at 0.95 confidence interval in all towns, except Auchi. Comparative analysis indicates strong relationship (R 2=0.667 between the resources spent in procuring clean water and accessibility-demand ratio in the region. Private sector participation recorded highest investment value of 62% on water sector; government and corporate organization recorded 23% and 15% respectively. Since private sector determines the progresses of water sector, this accounts for the exorbitant tariff of 1, 500 N per m 3 in this region. It is deduced that the most significant problems faced with water accessibility-affordability are transportation, finance and power supply with computed constraint index value of 47%, 40% and 13% respectively. Finally, Etasko-West and Esan Central are highly waterstressed. Government, corporate organization and private investors need to establish technically-based measures to ensure perfect accessibility and affordability of this scarce utility.

  11. Macroinvetebrate Assemblages as Indicators of Water Quality of the West Seti River, Bajhang, Nepal

    Directory of Open Access Journals (Sweden)

    Mohana Matangulu

    2017-08-01

    Full Text Available Water quality of the West Seti River, a tributary of the Karnali in West Nepal was assessed using macroinvertebrates as bioindicators. The main objective of the study was to assess the ecological water quality of the West Seti River and to generate a baseline data on macroinvertebrate assemblages. The sampling was conducted during December 2015 and a total of 11 sampling sites were selected from the West Seti River and its tributaries. Qualitative samples of macroinvertebrates were collected from different habitats. Selected physico-chemical parameters such as pH and temperature were estimated on-site. Dissolved oxygen (DO was estimated by Winkler’s method. The macroinvertebrate samples were enumerated and identified up to Family level following standard literature. Chi-square test was performed to see whether macroinvertebrate taxa varied significantly along the altitudinal gradient and between the West Seti River and its tributaries. An ecological assessment tool Nepalese Biotic Score/ Average Score Per Taxon (NEPBIOS/ASPT was applied to assess the water quality of the sampling sites. The pH value ranged from 7.9 to 8.7 indicating the alkaline nature of the river. A total of 1666 individuals belonging to 34 Families and 7 Orders of macro-invertebrates were observed. The highest diversity of the macroinvertebrate taxa was observed at site T5 with nineteen Families whereas the lowest taxa diversity was observed at R3 with only five Families. The variation in macroinvertebrate assemblages between the sub-tropical and temperate zones; and the West Seti River and its tributaries were not significant. NEPBIOS/ASPT revealed a score of Water Quality Class of III-IV at Site R3 indicating that the site was polluted. This site was characterized by the abundance of red Chironomids which are considered as the indicators of organic pollution.International Journal of EnvironmentVolume-6, Issue-3, Jun-Aug 2017, page: 25-45

  12. promoting integrated water resources management in south west

    African Journals Online (AJOL)

    eobe

    was that many of the professionals in the water sector organizations ( .... project basis as a "tack-on" to the main contract of ... natural asset that needs to be maintained to ensure ..... in Figure 2, through joint research, education, training,.

  13. K West Basin Integrated Water Treatment System (IWTS) E-F Annular Filter Vessel Accident Calculations

    Energy Technology Data Exchange (ETDEWEB)

    PIEPHO, M.G.

    2000-01-10

    Four bounding accidents postulated for the K West Basin integrated water treatment system are evaluated against applicable risk evaluation guidelines. The accidents are a spray leak during fuel retrieval, spray leak during backflushing a hydrogen explosion, and a fire breaching filter vessel and enclosure. Event trees and accident probabilities are estimated. In all cases, the unmitigated dose consequences are below the risk evaluation guidelines.

  14. Variations in tidal constituents along the nearshore waters of Karnataka, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Dora, G.U.; Philip, C.S.; Pednekar, P.S.; Singh

    . Coast. Res., vol.27(5); 2011; 824-829 Variations in tidal constituents along the nearshore waters of Karnataka, west coast of India V.Sanil Kumar, G. Udhaba Dora, Sajive Philip, P.Pednekar and JaiSingh Ocean Engineering, National Institute...

  15. K West Basin Integrated Water Treatment System (IWTS) E-F Annular Filter Vessel Accident Calculations

    Energy Technology Data Exchange (ETDEWEB)

    RITTMANN, P.D.

    1999-10-07

    Three bounding accidents postdated for the K West Basin integrated water treatment system are evaluated against applicable risk evaluation guidelines. The accidents are a spray leak during fuel retrieval, spray leak during backflushing, and a hydrogen explosion. Event trees and accident probabilities are estimated. In all cases, the unmitigated dose consequences are below the risk evaluation guidelines.

  16. Hydro-ecological relations in the Delta Waters of the South-West Netherlands

    NARCIS (Netherlands)

    Baptist, H.J.M.; Bijlsma, I.; Engel, H.; Haperen, A.A.M. van; Hoog, J.E.W. de; Iedema, C.W.; Kuipers, J.W.M.; Meininger, P.L.; Meire, P.M.; Mulder, J.P.M.; Nienhuis, P.H.; Seys, J.; Steenkamp, B.P.C.; Ysebaert, T.

    1989-01-01

    Before human interference in the Delta of the South-West Netherlands, the hydro-ecological relations in the waters of this Delta were taken very much for granted. As a result of the man-made changes, the natural relations disappeared. The construction of the Delta Works completely altered the face

  17. Hydro-ecological relations in the Delta Waters of the South-West Netherlands

    NARCIS (Netherlands)

    Baptist, H.J.M.; Bijlsma, I.; Engel, H.; Haperen, A.A.M. van; Hoog, J.E.W. de; Iedema, C.W.; Kuipers, J.W.M.; Meininger, P.L.; Meire, P.M.; Mulder, J.P.M.; Nienhuis, P.H.; Seys, J.; Steenkamp, B.P.C.; Ysebaert, T.

    1989-01-01

    Before human interference in the Delta of the South-West Netherlands, the hydro-ecological relations in the waters of this Delta were taken very much for granted. As a result of the man-made changes, the natural relations disappeared. The construction of the Delta Works completely altered the face o

  18. Hydro-ecological relations in the Delta Waters of the South-West Netherlands

    NARCIS (Netherlands)

    Baptist, H.J.M.; Bijlsma, I.; Engel, H.; Haperen, A.A.M. van; Hoog, J.E.W. de; Iedema, C.W.; Kuipers, J.W.M.; Meininger, P.L.; Meire, P.M.; Mulder, J.P.M.; Nienhuis, P.H.; Seys, J.; Steenkamp, B.P.C.; Ysebaert, T.

    1989-01-01

    Before human interference in the Delta of the South-West Netherlands, the hydro-ecological relations in the waters of this Delta were taken very much for granted. As a result of the man-made changes, the natural relations disappeared. The construction of the Delta Works completely altered the face o

  19. Popular music from Greenland

    DEFF Research Database (Denmark)

    Otte, Andreas Roed

    Popular music from Greenland – Globalization, nationalism and performance of place. This thesis is based on fieldwork done within the popular music scene in Greenland from 2008 to 2014. It engages with the question of how music and conceptions of the nation (Greenland) affect each other in social...... spaces, and analyses on how popular music can be used to construct senses of place and situate individuals within these places. The thesis is centered on four articles that engage with Greenlandic popular music from different perspectives. The first article looks at the historical development in inducing...... a sense of place in popular music. The second probes different strategies for co-branding popular music and Greenland. The third is concerned with music consumption patterns among Greenlandic youth. And the fourth article engages with an alternative form of nationalism found within the Nuuk underground...

  20. Hydrography and climate of the last 4,400 years in a SW Greenland fjord – implications for Labrador Sea palaeoceanography

    DEFF Research Database (Denmark)

    Seidenkrantz, Marit-Solveig; Aagaard-Sørensen, Steffen; Sulsbrück, Henrik

    2007-01-01

    A multiproxy record including benthic foraminifera, diatoms and XRF data of a marine sediment core from a SW Greenland fjord provides a detailed reconstruction of the oceanographic and climatic variations of the region during the last 4,400 cal. years. The lower part of our record represents...... Atlantic region. Our data show that increased advection of Atlantic water (Irminger Sea Water) from the West Greenland Current into the Labrador Sea was a typical feature of Northeast Atlantic cooling episodes such as the ‘Little Ice Age’ and the ‘European Dark Ages’, while the advection of Irminger Sea...... Water decreased significantly during warm episodes such as the ‘Mediaeval Warm Period’ and the ‘Roman Warm Period’. Whereas the Mediaeval Warm Period was characterised by relatively cool climate as suggested by low melt-water production, the preceding Dark Ages display higher melt-water runoff...

  1. Water quality trends in the Blackwater River watershed, West Virginia

    Science.gov (United States)

    Smith, Jessica; Welsh, Stuart; Anderson, James T.; Fortney, Ronald H.

    2015-01-01

    An understanding of historic and current water quality is needed to manage and improve aquatic communities within the Blackwater River watershed, WV. The Blackwater River, which historically offered an excellent Salvelinus fontinalis (Brook Trout) fishery, has been affected by logging, coal mining, use of off-road vehicles, and land development. Using information-theoretic methods, we examined trends in water quality at 12 sites in the watershed for the 14 years of 1980–1993. Except for Beaver Creek, downward trends in acidity and upward trends in alkalinity, conductivity, and hardness were consistent with decreases in hydrogen ion concentration. Water-quality trends for Beaver Creek were inconsistent with the other sites and reflect ongoing coal-mining influences. Dissolved oxygen trended downward, possibly due to natural conditions, but remained above thresholds that would be detrimental to aquatic life. Water quality changed only slightly within the watershed from 1980–1993, possibly reflecting few changes in development and land uses during this time. These data serve as a baseline for future water-quality studies and may help to inform management planning.

  2. Semen quality in Greenland

    OpenAIRE

    Toft, Gunnar; Pedersen, Henning Sloth; Bonde, Jens Peter; research team, INUENDO

    2004-01-01

    Objectives. To quantify semen quality in the Greenlandic population. Study design. A cross-sectional study including recently proven fertile men from four regions including nine municipalities and one settlement in Greenland. Methods. The samples were analysed for sperm cell concentrations and motility using standard methods. Results. In total 201 semen samples were collected. The median sperm cell concentration of fertile men in Greenland was 53 x106 sperm cells/ml, with a median sperm cell ...

  3. Valanginian ammonites in East Greenland

    DEFF Research Database (Denmark)

    Alsen, Peter

    2001-01-01

    ammonites, Boreal, Tethys, bed-by-bed collection, Valanginian, Wollaston Forland, East Greenland......ammonites, Boreal, Tethys, bed-by-bed collection, Valanginian, Wollaston Forland, East Greenland...

  4. U.S. Geological Survey Virginia and West Virginia Water Science Center

    Science.gov (United States)

    Jastram, John D.

    2017-08-22

    The U.S. Geological Survey (USGS) serves the Nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life. In support of this mission, the USGS Virginia and West Virginia Water Science Center works in cooperation with many entities to provide reliable, impartial scientific information to resource managers, planners, and the public.

  5. WATER QUALITY AND SOCIO-ECONOMICS FACTORS AFFECTING FISH PRODUCTION IN CIRATA RESERVOIR, WEST JAVA, INDONESIA

    OpenAIRE

    Nadia, Istiqomah

    2014-01-01

    The study was aimed to investigate socio-economics factor affecting fish production and to estimate water quality factor affecting fish production in Cirata Reservoir, West Java, Indonesia. Data were obtained from 115 farmers spread over 3 districts in the area of study. Cross section data of socio-economics factors were obtained from the farmer and examined in the study. In addition, historical data of water quality were gathered from the institution. Cobb-Douglass production function was us...

  6. Estimation of water turnover rates of captive West Indian manatees (Trichechus manatus) held in fresh and salt water.

    Science.gov (United States)

    Ortiz, R M; Worthy, G A; Byers, F M

    1999-01-01

    The ability of West Indian manatees (Trichechus manatus) to move between fresh and salt water raises the question of whether manatees drink salt water. Water turnover rates were estimated in captive West Indian manatees using the deuterium oxide dilution technique. Rates were quantified in animals using four experimental treatments: (1) held in fresh water and fed lettuce (N=4), (2) held in salt water and fed lettuce (N=2), (3) acutely exposed to salt water and fed lettuce (N=4), and (4) chronically exposed to salt water with limited access to fresh water and fed sea grass (N=5). Animals held in fresh water had the highest turnover rates (145+/-12 ml kg-1 day-1) (mean +/- s.e.m.). Animals acutely exposed to salt water decreased their turnover rate significantly when moved into salt water (from 124+/-15 to 65+/-15 ml kg-1 day-1) and subsequently increased their turnover rate upon re-entry to fresh water (146+/-19 ml kg-1 day-1). Manatees chronically exposed to salt water had significantly lower turnover rates (21+/-3 ml kg-1 day-1) compared with animals held in salt water and fed lettuce (45+/-3 ml kg-1 day-1). Manatees chronically exposed to salt water and fed sea grass had very low turnover rates compared with manatees held in salt water and fed lettuce, which is consistent with a lack of mariposia. Manatees in fresh water drank large volumes of water, which may make them susceptible to hyponatremia if access to a source of Na+ is not provided.

  7. Greenland and Natural Resources

    DEFF Research Database (Denmark)

    Lyck, Lise

    Greenland policy can delay and maybe change the future of the forecasted development of the use of natural resources. This book is relevant for anyone interested in Greenland in general and the development of Greenland both politically and economically and in relation natural resources.......The Greenland development is a story about: Having a hinterland position in relation to the global development. An indigenous people achieving more political influence. How conflicts and discussions on power and ownership of the subsurface resources between a state and an autonomy (Home Rule) can...

  8. Identifying Energy Savings in Water and Wastewater Plants - West Virginia

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-03-01

    Since 1976, Industrial Assessment Centers (IACs) administered by the U.S. Department of Energy have supported small and medium-sized American manufacturers to reduce their energy use and improve their productivity and competitiveness. DOE is now offering up to 50 assessments per year at no cost to industrial or municipal water and wastewater plants.

  9. Uncharted Waters: Communicating Health Risks During the 2014 West Virginia Water Crisis.

    Science.gov (United States)

    Thomas, Tracey L; Friedman, Daniela B; Brandt, Heather M; Spencer, S Melinda; Tanner, Andrea

    2016-09-01

    This study is among the first to examine how health risks are communicated through traditional and social media during a public health crisis. Using an innovative research approach, the study combined a content analysis with in-depth interviews to examine and understand how stakeholders involved in crisis response perceived media coverage after a chemical spill contaminated the drinking water of 300,000 West Virginia residents. A content analysis of print, television, and online media stories and tweets revealed that health risk information was largely absent from crisis coverage. Although traditional media stories were significantly more likely to include health information compared to tweets, public health sources were underutilized in traditional media coverage. Instead, traditional media favored the use of government sources outside the public health field, which stakeholders suggested was problematic because of a public distrust of officials and official information during the crisis. Results also indicated that Twitter was not a common or reliable source for health information but was important in the spread of other types of information. Ultimately, the study highlights a need for more deliberate media coverage of health risks and provides insight into how Twitter is used to spread crisis information.

  10. Summary of West Virginia Water-Resource Data through September 2008

    Science.gov (United States)

    Evaldi, R.D.; Ward, S.M.; White, J.S.

    2009-01-01

    The West Virginia Water Science Center of the U.S. Geological Survey, in cooperation with State and Federal agencies, obtains a large amount of data pertaining to the water resources of West Virginia each water year. A water year is the 12-month period beginning October 1 and ending September 30. These data, accumulated during many years, constitute a valuable database for developing an improved understanding of the water resources of the State. These data are maintained in the National Water Information System (NWIS) and are available through its World-Wide Web interface, NWISWeb, at http://waterdata.usgs.gov/wv/nwis. Data can be retrieved in a variety of common formats, and a tutorial is available at http://nwis.waterdata.usgs.gov/tutorial. Location information for all continuous-record gaging stations operated in West Virginia through September 2008 is provided in this report, as well as statistical summaries of the available daily records. This report can serve as an index to the daily records data available on the World-Wide Web. Hydrologic data for nearly all of the gaging stations identified in this report are also available in the annual publication series titled Water-Resources Data - West Virginia. This series of annual reports for West Virginia began with the 1961 water year with a report that contained only data relating to quantities of surface water. For the 1964 water year, a similar report was introduced that contained only data relating to water quality. Beginning with the 1975 water year, the report format was changed to include data on quantities of surface water, quality of surface water and groundwater, and groundwater levels. Prior to the introduction of the Water-Resources Data - West Virginia series and for several water years concurrent with it, water-resources data for West Virginia were published in U.S. Geological Survey Water-Supply Papers. Data on stream discharge and stage and on lake or reservoir contents and stage through September

  11. First record of Taenia ovis krabbei muscle cysts in muskoxen from Greenland.

    Science.gov (United States)

    Raundrup, Katrine; Al-Sabi, Mohammad Nafi Solaiman; Kapel, Christian Moliin Outzen

    2012-03-23

    A first record of Taenia ovis krabbei muscle cysts in a muskoxen (Ovibos moschatus) from the Kangerlussuaq population in West Greenland suggests that introduced muskoxen now contributes to the transmission of this parasite in addition to previous observations from caribou (Rangifer tarandus). Muskoxen and caribou are the only wild ungulates in Greenland.

  12. A water sustainability index for West Java. Part 1: developing the conceptual framework.

    Science.gov (United States)

    Juwana, I; Perera, B J C; Muttil, N

    2010-01-01

    Sustainable water resources management is essential since it ensures the integration of social, economical and environmental issues into all stages of water resources management. The development and application of water sustainability indices to achieve sustainable water management has been successfully done in the last few years. Although existing water sustainability indices have successfully provided information on current conditions of water resources and prioritised water related issues, they have been developed for specific case study areas. This study therefore aims at developing a water sustainability index for West Java, Indonesia. The overall steps for developing the index include developing a conceptual framework, application of Delphi technique to finalise the components/indicators of the index, applying the index to case studies and robustness analysis of the index. This paper, which is the first in a two-part series, discusses the first step, namely developing the conceptual framework of the West Java Water Sustainability Index (WJWSI). It outlines the criteria for identifying the initial set of components/indicators and based on those criteria, a detailed justification for selecting each component and indicator is also presented. The second paper of the series presents the application of Delphi technique to finalise the framework of WJWSI based on feedback from selected stakeholders. The remaining steps of developing WJWSI will be undertaken in the future.

  13. Determination of the water quality index ratings of water in the Mpumalanga and North West provinces, South Africa

    Science.gov (United States)

    Wanda, Elijah M. M.; Mamba, Bhekie B.; Msagati, Titus A. M.

    2016-04-01

    This study reports on the water quality index (WQI) of wastewater and drinking water in the Mpumalanga and North West provinces of South Africa. The WQI is one of the most effective tools available to water sustainability researchers, because it provides an easily intelligible ranking of water quality on a rating scale from 0 to 100, based on the ascription of different weightings to several different parameters. In this study the WQI index ratings of wastewater and drinking water samples were computed according to the levels of pH, electrical conductivity (EC), biochemical oxygen demand (BOD), E. coli, temperature, turbidity and nutrients (nitrogen and phosphates) found in water samples collected from the two provinces between June and December, 2014. This study isolated three groups of WQ-rated waters, namely: fair (with a WQI range = 32.87-38.54%), medium (with a WQI range = 56.54-69.77%) and good (with a WQI range = 71.69-81.63%). More specifically, 23%, 23% and 54% of the sampled sites registered waters with fair, medium and good WQ ratings respectively. None of the sites sampled during the entire period of the project registered excellent or very good water quality ratings, which would ordinarily indicate that no treatment is required to make it fit for human consumption. Nevertheless, the results obtained by the Eerstehoek and Schoemansville water treatment plants in Mpumalanga and North West provinces, respectively, suggest that substantial improvement in the quality of water samples is possible, since the WQI values for all of the treated samples were higher than those for raw water. Presence of high levels of BOD, low levels of dissolved oxygen (DO), E. coli, nitrates and phosphates especially in raw water samples greatly affected their overall WQ ratings. It is recommended that a point-of-use system should be introduced to treat water intended for domestic purposes in the clean-water-deprived areas.

  14. Holocene climate change in Arctic Canada and Greenland

    Science.gov (United States)

    Briner, Jason P.; McKay, Nicholas P.; Axford, Yarrow; Bennike, Ole; Bradley, Raymond S.; de Vernal, Anne; Fisher, David; Francus, Pierre; Fréchette, Bianca; Gajewski, Konrad; Jennings, Anne; Kaufman, Darrell S.; Miller, Gifford; Rouston, Cody; Wagner, Bernd

    2016-09-01

    This synthesis paper summarizes published proxy climate evidence showing the spatial and temporal pattern of climate change through the Holocene in Arctic Canada and Greenland. Our synthesis includes 47 records from a recently published database of highly resolved Holocene paleoclimate time series from the Arctic (Sundqvist et al., 2014). We analyze the temperature histories represented by the database and compare them with paleoclimate and environmental information from 54 additional published records, mostly from datasets that did not fit the selection criteria for the Arctic Holocene database. Combined, we review evidence from a variety of proxy archives including glaciers (ice cores and glacial geomorphology), lake sediments, peat sequences, and coastal and deep-marine sediments. The temperature-sensitive records indicate more consistent and earlier Holocene warmth in the north and east, and a more diffuse and later Holocene thermal maximum in the south and west. Principal components analysis reveals two dominant Holocene trends, one with early Holocene warmth followed by cooling in the middle Holocene, the other with a broader period of warmth in the middle Holocene followed by cooling in the late Holocene. The temperature decrease from the warmest to the coolest portions of the Holocene is 3.0 ± 1.0 °C on average (n = 11 sites). The Greenland Ice Sheet retracted to its minimum extent between 5 and 3 ka, consistent with many sites from around Greenland depicting a switch from warm to cool conditions around that time. The spatial pattern of temperature change through the Holocene was likely driven by the decrease in northern latitude summer insolation through the Holocene, the varied influence of waning ice sheets in the early Holocene, and the variable influx of Atlantic Water into the study region.

  15. Understanding changes in terrestrial water storage over West Africa between 2002 and 2014

    Science.gov (United States)

    Ndehedehe, Christopher; Awange, Joseph; Agutu, Nathan; Kuhn, Michael; Heck, Bernhard

    2016-02-01

    With the vast water resources of West Africa coming under threat due to the impacts of climate variability and human influence, the need to understand its terrestrial water storage (TWS) changes becomes very important. Due to the lack of consistent in-situ hydrological data to assist in the monitoring of changes in TWS, this study takes advantage of the Gravity Recovery and Climate Experiment (GRACE) monthly gravity fields to provide estimates of vertically integrated changes in TWS over the period 2002-2014, in addition to satellite altimetry data for the period 1993-2014. In order to understand TWS variability over West Africa, Principal Component Analysis (PCA), a second order statistical technique, and Multiple Linear Regression Analysis (MLRA) are employed. Results show that dominant patterns of GRACE-derived TWS changes are observed mostly in the West Sahel, Guinea Coast, and Middle Belt regions of West Africa. This is probably caused by high precipitation rates at seasonal and inter-annual time scales induced by ocean circulations, altitude and physiographic features. While the linear trend for the spatially averaged GRACE-derived TWS changes over West Africa for the study period shows an increase of 6.85 ± 1.67 mm/yr, the PCA result indicates a significant increase of 20.2 ± 5.78 mm/yr in Guinea, a region with large inter-annual variability in seasonal rainfall, heavy river discharge, and huge groundwater potentials. The increase in GRACE-derived TWS during this period in Guinea, though inconsistent with the lack of a significant positive linear trend in TRMM based precipitation, is attributed to a large water surplus from prolonged wet seasons and lower evapotranspiration rates, leading to an increase in storage and inundated areas over the Guinea region. This increase in storage, which is also the aftermath of cumulative increase in the volume of water not involved in surface runoff, forms the huge freshwater availability in this region. However, the

  16. Health expectancy in Greenland

    DEFF Research Database (Denmark)

    Iburg, K M; Brønnum-Hansen, Henrik; Bjerregaard, P

    2001-01-01

    Mortality and disease patterns in Greenland have greatly changed since the 1950s. Infectious diseases have decreased markedly; chronic diseases, suicides and violent deaths have increased.......Mortality and disease patterns in Greenland have greatly changed since the 1950s. Infectious diseases have decreased markedly; chronic diseases, suicides and violent deaths have increased....

  17. Studying health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Mulvad, Gert; Olsen, Jørn

    2003-01-01

    Health research in Greenland has contributed with several findings of interest for the global scientific community and has documented health problems and risk factors of importance for planning the local health care system. The study of how health develops in small, scattered communities during...... to that of the industrialized world, while still including local outbreaks of tuberculosis. Health research in Greenland is logistically difficult and costly, but offers opportunities not found elsewhere in the world. A long tradition of registration enhances the possibilities for research. A number of research institutions...... in Denmark and Greenland have conducted health research in Greenland for many years in cooperation with, among others, researchers in Canada and Alaska. National and international cooperation is supported by the Danish/Greenlandic Society for Circumpolar Health, the International Union for Circumpolar Health...

  18. Chemical quality of surface water in the West Branch Susquehanna River basin, Pennsylvania

    Science.gov (United States)

    McCarren, Edward F.

    1964-01-01

    The West Branch Susquehanna River is 228 miles long and drains 6,913 square miles of mountainous area in central Pennsylvania. Much of this area is forestcovered wilderness, part of which is reserved as State game land. Wild animals, such as deer, bear, turkey and grouse, are sheltered there, and many streams contain trout and other game fish. This helps to make the region one of the best hunting and fishing areas in Pennsylvania. The Congress has approved Federal funds for the construction of several reservoirs to prevent flooding of the main river and several of its tributaries. Water stored behind the dams will not be withdrawn below a minimum level designated as conservation pools. These pools will be available for recreation. Several headwater streams, such as Clearfield, Moshannon, and at times Sinnemahoning Creek, that carry drainage from coal mines are acid and contain high concentrations of dissolved solids, especially sulfates. These streams acidify the West Branch Susquehanna River downstream as far as Jersey Shore. One of the most influential tributaries affecting the quality of the West Branch Susquehanna River after they merge is Bald Eagle Creek. Bald Eagle Creek enters the main river downstream from Lock Haven which is approximately 100 river miles from the river's source. Because of its alkaline properties, water of Bald Eagle Creek can neutralize acidic water. Many streams draining small areas and several draining large areas such as Pine Creek, Lycoming Creek, and Loyalsock Creek are clear nearly neutral water low in dissolved solids whose pH is about 7.0 most of the time. These streams have a diluting and neutralizing effect on the quality of the West Branch Susquehanna River, so that from Williamsport downstream the river water is rarely acid, and for most of the time it is of good chemical quality.

  19. Study on radon and radium concentrations in drinking water in west region of Iran

    CERN Document Server

    Forozani, Ghasem

    2011-01-01

    One of the most important characterizations of social health is existence the availability of safe drinking water. Since one of the sources of water contamination is nuclear contamination from radon gas, so in this research radon 222 concentration levels in water supplies in the Toyserkan (a region located in the west of Iran) is investigated. For measuring radon gas in water wells and springs Lucas chamber method is used. Review the results of these measurements that taken from 15th place show that, only five sites have radon concentrations above the limit dose. To reduce radon concentration, it is better to keep water in open pools in contact with air before the water is delivered to users.

  20. Oceans Melting Greenland: Early Results from NASA's Ocean-Ice Mission in Greenland

    DEFF Research Database (Denmark)

    Fenty, Ian; Willis, Josh K.; Khazendar, Ala

    2016-01-01

    Melting of the Greenland Ice Sheet represents a major uncertainty in projecting future rates of global sea level rise. Much of this uncertainty is related to a lack of knowledge about subsurface ocean hydrographic properties, particularly heat content, how these properties are modified across...... the continental shelf, and about the extent to which the ocean interacts with glaciers. Early results from NASA's five-year Oceans Melting Greenland (OMG) mission, based on extensive hydrographic and bathymetric surveys, suggest that many glaciers terminate in deep water and are hence vulnerable to increased...... melting due to ocean-ice interaction. OMG will track ocean conditions and ice loss at glaciers around Greenland through the year 2020, providing critical information about ocean-driven Greenland ice mass loss in a warming climate....

  1. The Non-Market Value of Water Based Activities in the West of Ireland

    OpenAIRE

    Morrissey, Karyn; Moran, Caroline

    2011-01-01

    Coastal locations are traditional hotspots for tourism and leisure activity. The economic growth experienced in Ireland since the mid 1990s, coupled with an increased focus on health, leisure and improved lifestyle has contributed to an increase in participation in marine water-based activities (WBA). This paper examines the demand for and value of WBA offered by companies in the West of Ireland. Using parameter estimates derived from a truncated negative binomial model travel cost model (TCM...

  2. Meta-igneous (non-gneissic) tonalites and quartz-diorites from an extensive ca. 3800 Ma terrain south of the Isua supracrustal belt, southern West Greenland: constraints on early crust formation

    Science.gov (United States)

    Nutman, Allen P.; Bennett, Vickie C.; Friend, Clark R. L.; Norman, Marc D.

    In the Itsaq Gneiss Complex south of the Isua supracrustal belt (West Greenland) some areas of early Archaean tonalite and quartz-diorite are non-gneissic, free of pegmatite veins, and in rarer cases are undeformed with relict igneous textures and hence were little modified by heterogeneous ductile deformation under amphibolite facies conditions in several Archaean events. Such well-preserved early Archaean rocks are extremely rare. Tonalites are high Al, and have bulk compositions close to experimental liquids. Trace element abundances and modelling suggest that they probably originated as melts derived from basaltic compositions at sufficiently high pressures to require residual garnet + amphibolites +/- clinopyroxene in the source. The major element characteristics of the quartz-diorites suggest these were derived from more mafic magmas than the tonalites, and underwent either igneous differentiation or mixing with crustal material. As in modern arc magmas, high relative abundances of Sr, Ba, Pb, and alkali elements cannot be generated simply from a basaltic source formed by large degrees of melting of a depleted mantle. This may indicate an important role for fluids interacting with mafic rocks in generating the earliest preserved continental crust. The high Ba/Th, Ba/Nb, La/Nb and low Nb/Th, Ce/Pb, and Rb/Cs ratios of these tonalites are also observed in modern arc magmas. SHRIMP U-Pb zircon geochronology was undertaken on seven tonalites, one quartz-diorite, a thin pegmatitic vein and a thin diorite dyke. Cathodoluminescence images show the zircon populations of the quartz-diorite and tonalites are dominated by single-component oscillatory-zoned prismatic grains, which gave ages of 3806+/-5 to 3818+/-8Ma (2σ) (quartz-diorite and 5 tonalites) and 3795+/-3Ma (1 tonalite). Dating of recrystallised domains cutting oscillatory-zoned zircon indicates disturbance as early as 3800-3780Ma. There are rare ca. 3600Ma and 3800-3780Ma (very high U and low Th/U)<=20

  3. Diachronous retreat of the Greenland ice sheet during the last deglaciation

    Science.gov (United States)

    Sinclair, G.; Carlson, A. E.; Mix, A. C.; Lecavalier, B. S.; Milne, G.; Mathias, A.; Buizert, C.; DeConto, R.

    2016-08-01

    The last deglaciation is the most recent interval of large-scale climate change that drove the Greenland ice sheet from continental shelf to within its present extent. Here, we use a database of 645 published 10Be ages from Greenland to document the spatial and temporal patterns of retreat of the Greenland ice sheet during the last deglaciation. Following initial retreat of its marine margins, most land-based deglaciation occurred in Greenland following the end of the Younger Dryas cold period (12.9-11.7 ka). However, deglaciation in east Greenland peaked significantly earlier (13.0-11.5 ka) than that in south Greenland (11.0-10 ka) or west Greenland (10.5-7.0 ka). The terrestrial deglaciation of east and south Greenland coincide with adjacent ocean warming. 14C ages and a recent ice-sheet model reconstruction do not capture this progression of terrestrial deglacial ages from east to west Greenland, showing deglaciation occurring later than observed in 10Be ages. This model-data misfit likely reflects the absence of realistic ice-ocean interactions. We suggest that oceanic changes may have played an important role in driving the spatial-temporal ice-retreat pattern evident in the 10Be data.

  4. Water type quantification in the Skagerrak, the Kattegat and off the Jutland west coast

    Directory of Open Access Journals (Sweden)

    Trond Kristiansen

    2015-04-01

    Full Text Available An extensive data series of salinity, nutrients and coloured dissolved organic material (CDOM was collected in the Skagerrak, the northern part of the Kattegat and off the Jutland west coast in April each year during the period 1996–2000, by the Institute of Marine Research in Norway. In this month, after the spring bloom, German Bight Water differs from its surrounding waters by a higher nitrate content and higher nitrate/phosphate and nitrate/silicate ratios. The spreading of this water type into the Skagerrak is of special interest with regard to toxic algal blooms. The quantification of the spatial distributions of the different water types required the development of a new algorithm for the area containing the Norwegian Coastal Current, while an earlier Danish algorithm was applied for the rest of the area. From the upper 50 m a total of 2227 observations of salinity and CDOM content have been used to calculate the mean concentration of water from the German Bight, the North Sea (Atlantic water, the Baltic Sea and Norwegian rivers. The Atlantic Water was the dominant water type, with a mean concentration of 79%, German Bight Water constituted 11%, Baltic Water 8%, and Norwegian River Water 2%. At the surface the mean percentages of these water types were found to be 68%, 15%, 15%, and 3%, respectively. Within the northern part of the Skagerrak, closer to the Norwegian coast, the surface waters were estimated to consist of 74% Atlantic Water, 20% Baltic Water, and 7% Norwegian River Water. The analysis indicates that the content of German Bight Water in this part is less than 5%.

  5. Oxygen isotope ratios in the shell of Mytilus edulis: archives of glacier meltwater in Greenland?

    Directory of Open Access Journals (Sweden)

    T. D. Als

    2012-09-01

    Full Text Available Melting of the Greenland Ice Sheet (GrIS is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthåbsfjord (West Greenland, where glacier meltwater causes seasonal excursions with lower oxygen isotope water (δ18Ow values and salinity. The blue mussel (Mytilus edulis potentially records these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient seawater. As M. edulis shells are known to occur in raised shorelines and kitchen middens from previous Holocene warm periods, this species may be ideal in reconstructing past meltwater dynamics. We investigate its potential as a palaeo-meltwater proxy. First, we confirmed that M. edulis shell calcite oxygen isotope (δ18Oc values are in equilibrium with ambient water and generally reflect meltwater conditions. Subsequently we investigated if this species recorded the full range of δ18Ow values occurring during the years 2007 to 2010. Results show that δ18Ow values were not recorded at very low salinities (M. edulis δ18Oc values are suitable in reconstructing past meltwater amounts in most cases, but care has to be taken that shells are collected not too close to a glacier, but rather in the mid region or mouth of the fjord. The focus of future research will expand on the geographical and temporal range of the shell measurements by sampling mussels in other fjords in Greenland along a south-north gradient, and by sampling shells from raised shorelines and kitchen middens from prehistoric settlements in Greenland.

  6. Oxygen isotope ratios in the shell of Mytilus edulis: archives of glacier meltwater in Greenland?

    Directory of Open Access Journals (Sweden)

    T. D. Als

    2012-12-01

    Full Text Available Melting of the Greenland Ice Sheet (GrIS is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthåbsfjord (West Greenland, where glacier meltwater causes seasonal excursions with lower oxygen isotope water (δ18Ow values and salinity. The blue mussel (Mytilus edulis potentially records these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient seawater. As M. edulis shells are known to occur in raised shorelines and archaeological shell middens from previous Holocene warm periods, this species may be ideal in reconstructing past meltwater dynamics. We investigate its potential as a palaeo-meltwater proxy. First, we confirmed that M. edulis shell calcite oxygen isotope (δ18Oc values are in equilibrium with ambient water and generally reflect meltwater conditions. Subsequently we investigated if this species recorded the full range of δ18Ow values occurring during the years 2007 to 2010. Results show that δ18Ow values were not recorded at very low salinities (Mytilus edulis δ18Oc values are suitable in reconstructing past meltwater amounts in most cases, but care has to be taken that shells are collected not too close to a glacier, but rather in the mid-region or mouth of the fjord. The focus of future research will expand on the geographical and temporal range of the shell measurements by sampling mussels in other fjords in Greenland along a south–north gradient, and by sampling shells from raised shorelines and archaeological shell middens from prehistoric settlements in Greenland.

  7. Resilience and Renewable Energy Planning in Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2014-01-01

    Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable, and the ......Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable......, and the transition to a renewable energy system is proving no exception. Such a transition is particularly amplified in the context of Greenland – a country undergoing rapid transformation in many fields, including energy. Resilience theory offers an approach for how to plan for this energy transition, but how...... to translate resilience theory into planning practices remains underdeveloped. The paper begins by outlining some of the challenges in planning a transition to renewable energy, and sketching Greenland’s energy landscape. It then discusses the key characteristics of resilience thinking, before proposing...

  8. Effect of maize sowing area changes on agricultural water consumption from 2000 to 2010 in the West Liaohe Plain, China

    Institute of Scientific and Technical Information of China (English)

    YANG Ling; YANG Yan-zhao; FENG Zhi-ming; ZHENG Ya-nan

    2016-01-01

    TheWestLiaohe Plain is located in the eastern Inner Mongolia, known as the golden maize belt in China, where maize acreage has continued to rise in recent years. Water is the main limiting factor for maize production in the region, therefore, this study calculated the effect of maize sowing area changes on agricultural water consumption in the WestLiaohe Plain in 2000, 2005 and 2010, based on remote sensing and meteorological data. Maize remote sensing classiifcation was con-structed based on moderate-resolution imaging spectroradiometer, normalized difference vegatation index (MODIS NDVI) data. Then the maize sown area and water requirement and irrigation water resources were investigated. Finaly, the effect of the maize sowing area changes on agricultural water consumption in the West Liaohe Plain was systematicaly analyzed in 2000, 2005, and 2010. The results showed that maize sown areas rose from 2000 to 2010 and were concentrated in the center of the WestLiaohe Plain. Average per unit maize water deifcit amount also increased in an uneven distribution, increasing from the south, east and north to the center and west of the WestLiaohe Plain. The per unit area maize water deifcit increased from 2000 to 2010, and reached 266 mm in 2000, 272 mm in 2005 and 273 mm in 2010, respectively. And the study concluded that water deifcit during the whole growth period of maize in the West Liaohe Plain was deifned by a single peak curve. The maize water requirements increased with maize sowing area changes from 2000 to 2010, and the maize water requirements increased from 0.89 bilion m3 in 2000 to 1.19 bilion m3 in 2005, and 1.21 bilion m3 in 2010.

  9. Metal concentrations of river water and sediments in West Java, Indonesia.

    Science.gov (United States)

    Yasuda, Masaomi; Yustiawati; Syawal, M Suhaemi; Sikder, Md Tajuddin; Hosokawa, Toshiyuki; Saito, Takeshi; Tanaka, Shunitz; Kurasaki, Masaaki

    2011-12-01

    To determine the water environment and pollutants in West Java, the contents of metals and general water quality of the Ciliwung River in the Jakarta area were measured. High Escherichia coli number (116-149/mL) was detected downstream in the Ciliwung River. In addition to evaluate mercury pollution caused by gold mining, mercury contents of water and sediment samples from the Cikaniki River, and from paddy samples were determined. The water was not badly polluted. However, toxic metals such as mercury were detected at levels close to the baseline environmental standard of Indonesia (0.83-1.07 μg/g of sediments in the Cikaniki River). From analyses of the paddy samples (0.08 μg/g), it is considered that there is a health risk caused by mercury.

  10. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    the Arctic Ocean. A comprehensive database is created based on ice core and weather station data from Greenland within the period 1890-2014. Present day annual and seasonal mean values are computed for 326 locations in Greenland. Parameterization of the spatial distribution of temperature and δ18O are used...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  11. Child health in Greenland

    DEFF Research Database (Denmark)

    Niclasen, Birgit V L; Bjerregaard, Peter

    2007-01-01

    importance to the health of children in Greenland. More accurate data on child health are necessary in the future to secure better prioritization. It is suggested to construct a set of reliable indicators of child health in Greenland to monitor the health of children on a national and regional basis....... were sorted by topic, type, quality of study, and relevance for child health today, providing 47 articles. RESULTS: Children in Greenland have become taller and have improved their general health. The morbidity found in Greenlandic children is similar to that found elsewhere even though the magnitude....... Overweight and obesity have tripled in 20 years and are a health threat as well as constituting negative health behaviour. Social ill health, socioeconomic inequity, and sociocultural changes also influence health but their consequences are not well investigated in children. CONCLUSIONS: A relatively high...

  12. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    Greenland ice cores offer a unique opportunity to investigate the climate system behaviour. The objective of this PhD project is to investigate isotope modelling of present- day conditions and conduct model-data comparison using Greenland ice cores. Thus this thesis investigates how the integration...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  13. Telemedicine in Greenland

    DEFF Research Database (Denmark)

    Nielsen, Lasse Overballe; Krebs, Hans Jørgen; Albert, Nancy M.

    2017-01-01

    . Regarding challenges in using telemedicine in Greenland, the geographical and cultural context hinders accessibility to the Greenlandic healthcare system, and telemedicine equipment is not sufficiently mobile. CONCLUSION: Greenlandic citizens are positive toward telemedicine and regard telemedicine......BACKGROUND: Telemedicine may have the possibility to provide better access to healthcare delivery for the citizens. Telemedicine in arctic remote areas must be tailored according to the needs of the local population. Therefore, we need more knowledge about their needs and their view of telemedicine....... OBJECTIVE: The aim of this study has been to explore how citizens living in the Greenlandic settlements experience the possibilities and challenges of telemedicine when receiving healthcare delivery in everyday life. MATERIALS AND METHODS: Case study design was chosen as the overall research design...

  14. Greenland climate change

    DEFF Research Database (Denmark)

    Masson-Delmotte, Valerie; Swingedouw, D.; Landais, A.

    2012-01-01

    Climate archives available from deep-sea and marine shelf sediments, glaciers, lakes and ice cores in and around Greenland allow us to place the current trends in regional climate, ice sheet dynamics, and land surface changes in a broader perspective. We show that during the last decade (2000s...... regional climate and ice sheet dynamics. The magnitude and rate of future changes in Greenland temperature, in response to increasing greenhouse gas emissions, may be faster than any past abrupt events occurring under interglacial conditions. Projections indicate that within one century Greenland may......), atmospheric and sea-surface temperatures are reaching levels last encountered millennia ago when northern high latitude summer insolation was higher due to a different orbital configuration. Concurrently, records from lake sediments in southern Greenland document major environmental and climatic conditions...

  15. Evidence for a water system transition beneath Thwaites Glacier, West Antarctica.

    Science.gov (United States)

    Schroeder, Dustin M; Blankenship, Donald D; Young, Duncan A

    2013-07-23

    Thwaites Glacier is one of the largest, most rapidly changing glaciers on Earth, and its landward-sloping bed reaches the interior of the marine West Antarctic Ice Sheet, which impounds enough ice to yield meters of sea-level rise. Marine ice sheets with landward-sloping beds have a potentially unstable configuration in which acceleration can initiate or modulate grounding-line retreat and ice loss. Subglacial water has been observed and theorized to accelerate the flow of overlying ice dependent on whether it is hydrologically distributed or concentrated. However, the subglacial water systems of Thwaites Glacier and their control on ice flow have not been characterized by geophysical analysis. The only practical means of observing these water systems is airborne ice-penetrating radar, but existing radar analysis approaches cannot discriminate between their dynamically critical states. We use the angular distribution of energy in radar bed echoes to characterize both the extent and hydrologic state of subglacial water systems across Thwaites Glacier. We validate this approach with radar imaging, showing that substantial water volumes are ponding in a system of distributed canals upstream of a bedrock ridge that is breached and bordered by a system of concentrated channels. The transition between these systems occurs with increasing surface slope, melt-water flux, and basal shear stress. This indicates a feedback between the subglacial water system and overlying ice dynamics, which raises the possibility that subglacial water could trigger or facilitate a grounding-line retreat in Thwaites Glacier capable of spreading into the interior of the West Antarctic Ice Sheet.

  16. Q fever in Greenland

    DEFF Research Database (Denmark)

    Koch, Anders; Svendsen, Claus Bo; Christensen, Jens Jorgen

    2010-01-01

    We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection.......We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection....

  17. Q fever in Greenland

    DEFF Research Database (Denmark)

    Koch, Anders; Svendsen, Claus Bo; Christensen, Jens Jorgen

    2010-01-01

    We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection.......We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection....

  18. The Greenland Ramsar Sites

    DEFF Research Database (Denmark)

    Egevang, C.; Boertmann, D.

    The eleven Ramsar sites in Greenland are reviewed in terms of their status as habitats for waterbirds and other fauna. Management and monitoring is proposed, as well as revisions of their boundaries. A number of potential new Ramsar sites are described......The eleven Ramsar sites in Greenland are reviewed in terms of their status as habitats for waterbirds and other fauna. Management and monitoring is proposed, as well as revisions of their boundaries. A number of potential new Ramsar sites are described...

  19. Stable oxygen isotope variability in two contrasting glacier river catchments in Greenland

    Science.gov (United States)

    Yde, Jacob C.; Knudsen, Niels T.; Steffensen, Jørgen P.; Carrivick, Jonathan L.; Hasholt, Bent; Ingeman-Nielsen, Thomas; Kronborg, Christian; Larsen, Nicolaj K.; Mernild, Sebastian H.; Oerter, Hans; Roberts, David H.; Russell, Andrew J.

    2016-03-01

    Analysis of stable oxygen isotope (δ18O) characteristics is a useful tool to investigate water provenance in glacier river systems. In order to attain knowledge on the diversity of δ18O variations in Greenlandic rivers, we examined two contrasting glacierised catchments disconnected from the Greenland Ice Sheet (GrIS). At the Mittivakkat Gletscher river, a small river draining a local temperate glacier in southeast Greenland, diurnal oscillations in δ18O occurred with a 3 h time lag to the diurnal oscillations in run-off. The mean annual δ18O was -14.68 ± 0.18 ‰ during the peak flow period. A hydrograph separation analysis revealed that the ice melt component constituted 82 ± 5 % of the total run-off and dominated the observed variations during peak flow in August 2004. The snowmelt component peaked between 10:00 and 13:00 local time, reflecting the long travel time and an inefficient distributed subglacial drainage network in the upper part of the glacier. At the Kuannersuit Glacier river on the island Qeqertarsuaq in west Greenland, the δ18O characteristics were examined after the major 1995-1998 glacier surge event. The mean annual δ18O was -19.47 ± 0.55 ‰. Despite large spatial variations in the δ18O values of glacier ice on the newly formed glacier tongue, there were no diurnal oscillations in the bulk meltwater emanating from the glacier in the post-surge years. This is likely a consequence of a tortuous subglacial drainage system consisting of linked cavities, which formed during the surge event. Overall, a comparison of the δ18O compositions from glacial river water in Greenland shows distinct differences between water draining local glaciers and ice caps (between -23.0 and -13.7 ‰) and the GrIS (between -29.9 and -23.2 ‰). This study demonstrates that water isotope analyses can be used to obtain important information on water sources and the subglacial drainage system structure that is highly desired for understanding glacier hydrology.

  20. Use of clay from kangerlussuaq in the Greenlandic construction industry

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Villumsen, Arne; Ottosen, Lisbeth M.

    2010-01-01

    Clay material from Kangerlussuaq in West Greenland was characterised and its possible use for the production of bricks, expanded clay products and inert filler material was investigated. It was generally found that it was possible to use the clay in all of the above mentioned materials, although,...

  1. Evaluating Adaptive Governance Approaches to Sustainable Water Management in North-West Thailand

    Science.gov (United States)

    Clark, Julian R. A.; Semmahasak, Chutiwalanch

    2013-04-01

    Adaptive governance is advanced as a potent means of addressing institutional fit of natural resource systems with prevailing modes of political-administrative management. Its advocates also argue that it enhances participatory and learning opportunities for stakeholders over time. Yet an increasing number of studies demonstrate real difficulties in implementing adaptive governance `solutions'. This paper builds on these debates by examining the introduction of adaptive governance to water management in Chiang Mai province, north-west Thailand. The paper considers, first, the limitations of current water governance modes at the provincial scale, and the rationale for implementation of an adaptive approach. The new approach is then critically examined, with its initial performance and likely future success evaluated by (i) analysis of water stakeholders' opinions of its first year of operation; and (ii) comparison of its governance attributes against recent empirical accounts of implementation difficulty and failure of adaptive governance of natural resource management more generally. The analysis confirms the potentially significant role that the new approach can play in brokering and resolving the underlying differences in stakeholder representation and knowledge construction at the heart of the prevailing water governance modes in north-west Thailand.

  2. The summer 2012 Greenland heat wave

    DEFF Research Database (Denmark)

    Bonne, Jean-Louis; Steen-Larsen, Hans Christian; Risi, Camille

    2015-01-01

    During 7–12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations...

  3. Resilience and Renewable Energy Planning in Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2014-01-01

    , and the transition to a renewable energy system is proving no exception. Such a transition is particularly amplified in the context of Greenland – a country undergoing rapid transformation in many fields, including energy. Resilience theory offers an approach for how to plan for this energy transition, but how...... to translate resilience theory into planning practices remains underdeveloped. The paper begins by outlining some of the challenges in planning a transition to renewable energy, and sketching Greenland’s energy landscape. It then discusses the key characteristics of resilience thinking, before proposing......Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable...

  4. Resilience and Renewable Energy Planning in Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2014-01-01

    Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable......, and the transition to a renewable energy system is proving no exception. Such a transition is particularly amplified in the context of Greenland – a country undergoing rapid transformation in many fields, including energy. Resilience theory offers an approach for how to plan for this energy transition, but how...... to translate resilience theory into planning practices remains underdeveloped. The paper begins by outlining some of the challenges in planning a transition to renewable energy, and sketching Greenland’s energy landscape. It then discusses the key characteristics of resilience thinking, before proposing...

  5. Reconstructing the dynamics of the Greenland ice sheet during the last deglaciation

    Science.gov (United States)

    Keisling, Benjamin; DeConto, Robert

    2016-04-01

    Today, some outlet glaciers of the Greenland ice sheet (GrIS) are rapidly retreating and may mobilize large volumes of interior ice in the coming centuries. The last period that saw such dramatic, sustained retreat of the GrIS was the last deglaciation, when the ice sheet retreated from its Last Glacial Maximum (LGM) extent. Previous studies have used relative sea level observations to constrain changes in ice thickness and retreat timing during the deglaciation (e.g. Fleming and Lambert 2004, Simpson et al. 2009, Lecavalier et al. 2014). Here we build on these studies by isolating the drivers of ice-sheet retreat, and their spatial and temporal dynamics, during this period. Inclusion of ice-cliff failure and hydrofracturing parameterizations in our model has resulted in a better fit to paleodata for the Antarctic ice sheet, but this modeling approach has not been applied to the GrIS. Here we use a three-dimensional hybrid SSA/SIA ice-sheet model (Pollard et al. 2015) at 10km resolution over Greenland to simulate the last deglaciation. Boundary conditions for the last glacial maximum produce an LGM ice sheet with 3.81 meters sea level equivalent (m s.l.e.) of additional ice. The LGM ice sheet advances to the shelf-break in west, south, and east Greenland with an expansive ice shelf extending across Davis Strait. Applying modern atmospheric and oceanic forcing to the LGM ice sheet yields 1.25 and 1.09 m s.l.e. of melt, respectively, and 1.72 m s.l.e. for both. Ocean warming initially results in a higher rate and magnitude of retreat, but increased surface evaporation over open water results in additional accumulation that offsets losses in 10 kyr simulations. Here, we test the sensitivity of the magnitude of deglacial ice-sheet retreat to uncertainty in bedrock elevation and basal slding coefficients, the applied climate forcing, and the mass balance scheme (positive degree-day or energy balance). We also implement a deglacial climate forcing based on recently

  6. Nutrient environment of red tide- infested waters off south-west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, T.; Shaiju, P.; Laluraj, C.M.; Balachandran, K.K.; Nair, M.; George, R.; Nair, K.K.C.; Sahayak, S.; Prabhakaran, M.P.

    /Accepted: 28 August 2007 /Published online: 19 September 2007 # Springer Science + Business Media B.V. 2007 Abstract The bloom-infested waters along the south- west coast of India were assessed to bring about... by prevailing winds and currents. Hence, it is likely that, the dinoflagellates observed off Kollam must have moved in to this region (lat.8°20′N, long. 76°29′E). These advective processes are often strong enough to transport the organisms over large dis- tances...

  7. The behaviour of aluminium in waters of the Mandovi estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Upadhyay, S.; SenGupta, R.

    (1995) 261-276 The behaviour of aluminium in waters of the Mandovi estuary, west coast of India S. Upadhyay aY1, R. Sen Gupta b a Department of Marine Science, Goa University. Goa 403203. India b National Institute of Oceanography, Dona Paula, Goa...- tems (Plankey and Patterson, 1987), only a few ’ Present address: School of Environmental Sciences, Univer- sity of East Anglia, Norwich, NR4 7TJ, UK. studies are available concerning its behaviour in estuaries (Hosokawa et al., 1970; Hydes and Liss...

  8. Seasonal changes in Fe along a glaciated Greenlandic fjord.

    Science.gov (United States)

    Hopwood, Mark; Connelly, Douglas; Arendt, Kristine; Juul-Pedersen, Thomas; Stinchcombe, Mark; Meire, Lorenz; Esposito, Mario; Krishna, Ram

    2016-03-01

    Greenland's ice sheet is the second largest on Earth, and is under threat from a warming Arctic climate. An increase in freshwater discharge from Greenland has the potential to strongly influence the composition of adjacent water masses with the largest impact on marine ecosystems likely to be found within the glaciated fjords. Here we demonstrate that physical and chemical estuarine processes within a large Greenlandic fjord are critical factors in determining the fate of meltwater derived nutrients and particles, especially for non-conservative elements such as Fe. Concentrations of Fe and macronutrients in surface waters along Godthåbsfjord, a southwest Greenlandic fjord with freshwater input from 6 glaciers, changed markedly between the onset and peak of the meltwater season due to the development of a thin (removing Fe from surface waters before it can be exported to coastal seas.

  9. Constraints on mantle evolution from 187Os/ 188Os isotopic compositions of Archean ultramafic rocks from southern West Greenland (3.8 Ga) and Western Australia (3.46 Ga)

    Science.gov (United States)

    Bennett, Victoria C.; Nutman, Allen P.; Esat, Tezer M.

    2002-07-01

    Initial 187Os/ 188Os isotopic compositions for geochronologically and geologically well -constrained 3.8-Ga spinel peridotites from the Itsaq Gneiss Complex of southern West Greenland and chromite separates from 3.46-Ga komatiites from the Pilbara region of Western Australia have been determined to investigate the osmium isotopic evolution of the early terrestrial mantle. The measured compositions of 187Os/ 188Os(0) = 0.10262 ± 2, from an olivine separate, and 0.10329 ± 3, for a spinel separate from ˜3.8-Ga peridotite G93/42, are the lowest yet reported from any terrestrial sample. The corrections for in situ decay over 3.8 Ga for these low Re/Os phases are minimal and change the isotopic compositions by only 0.5 and 2.2% for the spinel and the olivine, respectively, resulting in 187Os/ 188Os (3.8 Ga) = 0.1021 ± 0.0002 and 0.1009 ± 0.0002, respectively. These data extend direct measurement of Os isotopic compositions to much earlier periods of Earth history than previously documented and provide the best constraints on the Os isotopic composition of the early Archean terrestrial mantle. Analyses of Pilbara chromites yield 3.46-Ga mantle compositions of 0.1042 ± 0.0002 and 0.1051 ± 0.0002. These new data, combined with published initial Os isotopic compositions from late Archean and early Proterozoic samples, are compatible with the mantle, or at least portions of it, evolving from a solar system initially defined by meteorites to a modern composition of 187Os/ 188Os(0) = 0.1296 ± 0.0008 as previously suggested from peridotite xenolith data ( Meisel et al., 2001); the associated 187Re/ 188Os(0) = 0.435 ± 0.005. Thus, chondritic 187Os/ 188Os compositions were a feature of the upper mantle for at least 3.8 billion years, requiring chondritic Re/Os ratios to have been a characteristic of the very early terrestrial mantle. In contrast, nonchondritic initial compositions of some Archean komatiites demonstrate that Os isotopic heterogeneity is an ancient feature

  10. Circulation and mixing of Mediterranean water west of the Iberian Peninsula

    Science.gov (United States)

    Daniault, N.; Mazé, J. P.; Arhan, M.

    1994-11-01

    The spreading of water of Mediterranean origin west of the Iberian Peninsula was studied with hydrographic data from several recent cruises and current measurements from the BORD-EST programme. The vertical breakdown of the "Mediterranean salt" content reveals the dominant contribution of the so-called lower core of the outflow (60%), and the significant fraction (22%) brought downward to levels below 1500 m by diffusion. Intense salinity maxima in the upper core (18%) are only encountered south of 38°N in the vein flowing northward along the continental slope, and at a few stations in the deep ocean. Apart from the coastally trapped vein, other preferred paths of the water mass are revealed by the horizontal distributions of salinity maximum and Mediterranean Water percentage. One is southward, west of the Gorringe Bank, and two northwestward ones lie around 40°N and west of the Galicia Bank. Year-long velocity measurements in the Tagus Basin show westward mean values of 7 × 10 -2 m s -1 at 1000 m associated with a very intense mesoscale variability. This variability is related to the pronounced dynamical signature of the outflow which favours instability in any branch having detached from the slope current. From a mixing point of view, the strong interleaving activity occurring near Cape St-Vincent is illustrated, but its contribution to the downstream salinity decrease in the coastally trapped vein is weak. Current and meddy detachment play the dominant role, with a scaling estimate of their associated lateral diffusivity of order 500 m 2 s -1. The statistical distribution of the density ratio parameter, which governs double-diffusion at the base of the Mediterranean Water, was found to be very tight around Rπ = 1.3 in the temperature range of 5°C< φ < 8°C. North of 40°N, the presence of a fraction of Labrador Sea Water in the underlying water is shown to decrease that parameter and should favour the formation of salt fingers.

  11. Substantial contribution to sea-level rise during the last interglacial from the Greenland ice sheet

    Science.gov (United States)

    Cuffey; Marshall

    2000-04-06

    During the last interglacial period (the Eemian), global sea level was at least three metres, and probably more than five metres, higher than at present. Complete melting of either the West Antarctic ice sheet or the Greenland ice sheet would today raise sea levels by 6-7 metres. But the high sea levels during the last interglacial period have been proposed to result mainly from disintegration of the West Antarctic ice sheet, with model studies attributing only 1-2 m of sea-level rise to meltwater from Greenland. This result was considered consistent with ice core evidence, although earlier work had suggested a much reduced Greenland ice sheet during the last interglacial period. Here we reconsider the Eemian evolution of the Greenland ice sheet by combining numerical modelling with insights obtained from recent central Greenland ice-core analyses. Our results suggest that the Greenland ice sheet was considerably smaller and steeper during the Eemian, and plausibly contributed 4-5.5 m to the sea-level highstand during that period. We conclude that the high sea level during the last interglacial period most probably included a large contribution from Greenland meltwater and therefore should not be interpreted as evidence for a significant reduction of the West Antarctic ice sheet.

  12. Phytoplankton Community Dynamics in West Lake After Drawing Water from the Qiantang River

    Institute of Scientific and Technical Information of China (English)

    魏印心; 李瑾; 虞左明

    2004-01-01

    Seventeen phytoplankton dominant species of 218 taxa were found to have contributed to more than 80% of the biomass after analysis of the January, 1955 to December, 1996 phytoplankton population at five stations in West Lake after Qiantang River water had been drawn into the lake for a decade. The seasonal fluctuations were obvious; the maximum cell density of 90.91×107-93.58×107 cells/L and biomass of 57.41-58.61 mg/L occurred mainly in summer of 1996,largely as a result of the development of Lyngbya contorta, Merismopedia tenuissima, Oscillatoria limnetica, Spirulina laxissima and Scenedesmus quadricauda, etc. at Stations 2 and 4. At Station 1 located near the inlet for drawing water from the Qiantang River, the species number, cell density, biomass, chlorophyll a concentration and physico-chemical parameters (except for total nitrogen) were obviously greater than those at the other four stations, also greater than the corresponding parameters before the drawing of water from the Qiantang River into the lake.Compared with the results of study on the phytoplankton community in 1980 before the drawing of Qiantang River into the lake, the species number and the total individual density were increased, the dominant species changed somewhat, the biomass was decreased. The water quality was improved (especially at Station 1) after the drawing of river water into the lake.Based on criteria for evaluating trophic status, the biological and chemical indicators such as species composition and dominant species, and other parameters such as annual mean value cell densities (36.06×107-51.27×107 cells/L), biomass (29.03-39.74 mg/L), chl a concentrations (41.29-67.67μg/L), total nitrigen (1.72-2.89 mg/L), total phosphorus (0.12-0.16 mg/L) obtained at Stations 2, 3, 4 and 5, showed that West Lake is still at eutrophic lake.

  13. Seawater Quality Characteristic of Greenland Coastal Waters in Summer%格陵兰海近海海域夏季海水水质特征分析

    Institute of Scientific and Technical Information of China (English)

    宋天泽

    2011-01-01

    Sampling of surface seawater, ice and runoff were carried out during the Arctic scientific expeditions in July in 2010, which was organized by Beijing Teenager Science and Technology Club. The study area was coastal waters of Greenland, Svalbard and Iceland. The water quality analysis results showed that F- and NO3-were not detected. Concentrations of macro -components in seawater were sequenced as C1- > Na+ > SO42- > Mg2+ > K+ > Ca2+ , which was accordant with general seawater. The ratio between concentration of all ions and chlorinity followed the Marcet - Dittmar Constant Ratios Law which testified that Greenland Sea was mainly re-charged by precipitation and runoff from mainland. Ion concentrations in seawater of inshore were much lower compared with that of offshore because surface seawater was recharged by runoff resulted from glacier melting. Despite NO3- was detected in runoff at Svalbard, the coastal seawater samples were determined without NO3- , which indicated that the NO3- in runoff was sufficiently diluted under the effect of ocean current.%2010年7月,在北京青少年科技俱乐部组织的北极科学考察活动过程中,对斯瓦尔巴德群岛、格陵兰岛以及冰岛的近海海域进行表层海水水样、冰样及陆地径流的采集.对采集样品的9项指标分析结果表明,海水样品中未检到F-和NO3-;其他离子含最的排序依次为:Cl-,Na+,SO42-,Mg2+,K+,Ca2+,与自然海水常规离子含量的排序基本一致;各离子含量与氯度的比值与恒比定律中给出的值基本一致,证明了北极海水主要受到陆地降水直接补给.近岸海水的离子含量远远低于远岸海水的原因是由于冰川融化,通过地表径流的方式补给表层海水有关.斯瓦尔巴德群岛的地表径流中存在有NO3-,但对所采海水样品的检验中,未检测到NO3-,说明地表径流中的NO3-在海水的对流等作用下得以充分稀释.

  14. Evaluation of chronic arsenic poisoning due to consumption of contaminated ground water in West Bengal, India

    Directory of Open Access Journals (Sweden)

    Asutosh Ghosh

    2013-01-01

    Full Text Available Background: Chronic arsenic poisoning is an important public health problem and most notable in West Bengal and Bangladesh. In this study different systemic manifestations in chronic arsenic poisoning were evaluated. Methods: A nonrandomized, controlled, cross-sectional, observational study was carried out in Arsenic Clinic, Institute of Postgraduate Medical Education and Research, Kolkata, West Bengal, over a period of 1 year 4 months. Seventy-three cases diagnosed clinically, consuming water containing arsenic ≥50 μg/L and having hair and nail arsenic level >0.6 μg/L, were included. Special investigations included routine parameters and organ-specific tests. Arsenic levels in the drinking water, hair, and nail were measured in all. Twenty-five nonsmoker healthy controls were evaluated. Results: Murshidabad and districts adjacent to Kolkata, West Bengal, were mostly affected. Middle-aged males were the common sufferers. Skin involvement was the commonest manifestation (100%, followed by hepatomegaly [23 (31.5%] with or without transaminitis [7 (9.58%]/portal hypertension [9 (12.33%]. Restrictive abnormality in spirometry [11 (15.06%], bronchiectasis [4 (5.47%], interstitial fibrosis [2 (2.73%], bronchogenic carcinoma [2 (2.73%], oromucosal plaque [7 (9.58%], nail hypertrophy [10 (13.69%], alopecia [8 (10.95%], neuropathy [5 (6.84%], and Electrocardiography abnormalities [5 (6.84%] were also observed. Conclusions: Mucocutaneous and nail lesions, hepatomegaly, and restrictive change in spirometry were the common and significant findings. Other manifestations were characteristic but insignificant.

  15. Flocculation alters the distribution and flux of melt-water supplied sediments and nutrients in the Arctic

    DEFF Research Database (Denmark)

    Markussen, Thor Nygaard; Andersen, Thorbjørn Joest; Ernstsen, Verner Brandbyge

    environment but comparatively little is known about the flocculation processes in the Arctic. We investigated flocculation dynamics from a melt-water river in the inner Disko Fjord, West Greenland. A novel, laser-illuminated camera system significantly improved the particle size measurement capabilities...

  16. Cholera outbreak secondary to contaminated pipe water in an urban area, West Bengal, India, 2006.

    Science.gov (United States)

    Bhunia, Rama; Ramakrishnan, Ramachandran; Hutin, Yvan; Gupte, Mohan D

    2009-01-01

    Outbreaks of cholera are common in West Bengal. In April 2006, Garulia municipality reported a cluster of diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures. We defined a case of diarrhea as occurrence of > or =3 loose/watery stools a day among the residents of Garulia since April 2006. We searched for cases of diarrhea in health care facilities and health camp. We conducted a gender- and age-matched case-control study to identify risk factors. We inspected the sanitation and water supply system. We collected rectal swabs from diarrhea patients and water specimens from the affected areas for laboratory investigation. Two hundred and ninety-eight cases of diarrhea were reported to various health care facilities (attack rate: 3.5/1000, no deaths). The attack rate was highest among children (6.4/1000). Vibrio cholerae El Tor O1 Inaba was isolated from two of 7 rectal swabs. The outbreak started on 10 April 2006, peaked on 26 April and lasted till 6 May. Cases clustered in an area distal to leaking water pipelines. Drinking municipal water exclusively was significantly associated with the illness (OR 13, 95% CI=6.5-27). Eight of the 12 water specimens from the affected area had fecal contamination and poor chlorine content. This outbreak was due to a contaminated municipal piped water supply and V. cholera 01 Inaba was possibly the causative organism.

  17. West Village Community: Quality Management Processes and Preliminary Heat Pump Water Heater Performance

    Energy Technology Data Exchange (ETDEWEB)

    Dakin, B.; Backman, C.; Hoeschele, M.; German, A.

    2012-11-01

    West Village, a multi-use project underway at the University of California Davis, represents a ground-breaking sustainable community incorporating energy efficiency measures and on-site renewable generation to achieve community-level Zero Net Energy (ZNE) goals. The project when complete will provide housing for students, faculty, and staff with a vision to minimize the community's impact on energy use by reducing building energy use, providing on-site generation, and encouraging alternative forms of transportation. This focus of this research is on the 192 student apartments that were completed in 2011 under Phase I of the West Village multi-year project. The numerous aggressive energy efficiency measures implemented result in estimated source energy savings of 37% over the B10 Benchmark. There are two primary objectives of this research. The first is to evaluate performance and efficiency of the central heat pump water heaters as a strategy to provide efficient electric water heating for net-zero all-electric buildings and where natural gas is not available on site. In addition, effectiveness of the quality assurance and quality control processes implemented to ensure proper system commissioning and to meet program participation requirements is evaluated. Recommendations for improvements that could improve successful implementation for large-scale, high performance communities are identified.

  18. West Village Community. Quality Management Processes and Preliminary Heat Pump Water Heater Performance

    Energy Technology Data Exchange (ETDEWEB)

    Dakin, B. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Backman, C. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); German, A. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2012-11-01

    West Village, a multi-use project underway at the University of California Davis, represents a ground-breaking sustainable community incorporating energy efficiency measures and on-site renewable generation to achieve community-level Zero Net Energy (ZNE) goals. When complete, the project will provide housing for students, faculty, and staff with a vision to minimize the community’s impact on energy use by reducing building energy use, providing on-site generation, and encouraging alternative forms of transportation. This focus of this research is on the 192 student apartments that were completed in 2011 under Phase I of the West Village multi-year project. The numerous aggressive energy efficiency measures implemented result in estimated source energy savings of 37% over the B10 Benchmark. There are two primary objectives of this research. The first is to evaluate performance and efficiency of the central heat pump water heaters as a strategy to provide efficient electric water heating for net-zero all-electric buildings and where natural gas is not available on site. In addition, effectiveness of the quality assurance and quality control processes implemented to ensure proper system commissioning and to meet program participation requirements is evaluated. Recommendations for improvements that could improve successful implementation for large-scale, high performance communities are identified.

  19. Water quality and streamflow data for the West Fork Trinity River in Forth Worth, Texas

    Science.gov (United States)

    McCutcheon, S.C.

    1985-01-01

    Water-quality data were collected on a 13.6-mile reach of the West Fork Trinity River in Fort Worth, Texas to test a dynamic Lagrangian model. Flow was steady. Loads of dissolved constituents varied with time at the beginning of the study reach and in the reach, primarily because of photosynthesis. River quality was fairly good despite low dissolved oxygen measured in the headwaters and the significant sewage load from the tributaries. Diel and longitudinal trends were defined by sampling at fixed sites and by following dyed parcels of water. Nitrification, deoxygenation, reaeration, and photosynthesis affected the dissolved oxygen balance. Independent estimates of some of the rate coefficients were 0.1 to 0.2, 0.8, and 0 to 3.6 , all per day, for deoxygenation, nitrification, and reaeration, respectively. (USGS)

  20. Solar hot water system installed at Quality Inn, Key West, Florida. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-04-01

    The solar energy hot water system installed in the Quality Inn, Key West, Florida, which consists of four buildings, is described. Three buildings are low-rise, two-story buildings containing 100 rooms. The fourth is a four-story building with 48 rooms. The solar system was designed to provide approximately 50% of the energy required for the domestic hot water system. The solar system consists of approximately 1400 ft/sup 2/ of flat plate collector, two 500 gal storage tanks, a circulating pump, and a controller. Operation of the system was begun in April 1978, and has continued to date with only three minor interruptions for pump repair. In the first year of operation, it was determined that the use of the solar facility resulted in 40% fuel savings.

  1. The quest for safe drinking water: an example from Guinea-Bissau (West Africa).

    Science.gov (United States)

    Bordalo, Adriano A; Savva-Bordalo, Joana

    2007-07-01

    While humans require water for life, one-sixth of our species lives without access to safe water. In Africa, the situation is particularly acute because of global warming, the progression of the Sahara desert, civil unrest and poor governance, population growth, migration and poverty. In rural areas, the lack of adequate safe water and sanitary infrastructures leaves millions with doubtful water quality, increasing the harshness of daily life. In this paper, a pilot study was conducted during the wet season on Bolama Island (Guinea-Bissau, West Africa), a UNESCO Man and the Biosphere Reserve. Twenty-eight shallow wells, supplying water to most of the population, were sampled for microbiological, physical and chemical water quality characteristics. A ten-parameter water quality index (WQI) adapted to tropical conditions was applied to compare the different wells. About 79% of the wells showed moderate to heavy fecal contamination. From the surveyed parameters, it was found that chemical contamination was less important, although all samples were acidic, with the pH averaging 5.12+/-0.08. The WQI was 43+/-4% (0%-worst; 100%-best quality), showing that the water from the majority of wells was polluted but should be suitable for domestic use after appropriate treatment. At the onset of the wet season, diarrhea represented 11.5% of all medical cases, 92.5% of which were children aged <15. This paper suggests inexpensive steps to reduce the fecal contamination and control the pH in order to increase the potability of the well water and, concomitantly, to raise the living standards of the population in one of the poorest countries of the world.

  2. The isotopic composition of dissolved cadmium in the water column of the West Philippine Sea

    Directory of Open Access Journals (Sweden)

    Shun-Chung eYang

    2014-11-01

    Full Text Available The dissolved concentration and isotopic compositions of cadmium (Cd in the seawater of the West Philippine Sea were determined. In general, Cd isotopic composition in the water column decreased with depth, with ε114/110Cd (ε114/110Cd = [(114Cd/110Cdsample / (114Cd/110CdNIST 3108 - 1]×10000 ranging from +7.2 to +10.1 in the top 60 m, from +4.8 to +5.1 between 100 and 150 m, peaking at +8.2 at 200 m, decreasing from +4.5 to +3.3 from 400 to 1000 m, and remaining constant at +3.0 from 1000 m and deeper. Different to a Rayleigh fractionation model, the isotopic composition and log scale concentrations of Cd do not exhibit a linear relationship. However, from the deep water to thermocline, the variations in Cd concentration and ε114/110Cd are relevant to the variations of temperature and salinity, indicating that water mixing is the dominant processes determining the concentration and isotopic composition in the interval. At 200 m where North Pacific Tropic Water dominates the water mass, the elevated ε114/110Cd could be linked to the composition in the upper portions of the water mass. In the top 150 m, the ε114/110Cd varies similarly to the phytoplankton community structures, implying that Cd uptake by various phytoplankton species may be associated with the isotopic variation. However, the effects of atmospheric inputs to the ε114/110Cd in the surface water cannot be excluded. A box model calculation is used to constrain the contributions of various processes to the Cd isotopes of surface water, and the results indicate that the Cd concentration and isotopic composition in most of the water body of the region are controlled by physical mixing, while the effects of biological fractionation and atmospheric inputs are limited in the euphotic zone.

  3. How Greenland melts

    Directory of Open Access Journals (Sweden)

    van den Broeke M.R.

    2010-12-01

    Full Text Available Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that maybe the ice sheet returns to normal after a period of volume increase and mass gain. By modelling and observing the individual components of the ice sheet mass balance, i.e. snowfall, meltwater runoff and iceberg production, we are able to identify the processes that led to the recent mass loss. We conclude that the Greenland ice sheet is significantly out of balance. Acceleration of outlet glaciers and increased runoff have contributed equally to recent Greenland mass loss. The potential for mass loss by surface processes, however, was three times greater than actually observed, due to refreezing and enhanced snowfall.

  4. CNS infections in Greenland

    DEFF Research Database (Denmark)

    Nordholm, Anne Christine; Søborg, Bolette; Andersson, Mikael

    2017-01-01

    BACKGROUND: Indigenous Arctic people suffer from high rates of infectious diseases. However, the burden of central nervous system (CNS) infections is poorly documented. This study aimed to estimate incidence rates and mortality of CNS infections among Inuits and non-Inuits in Greenland...... and in Denmark. METHODS: We conducted a nationwide cohort study using the populations of Greenland and Denmark 1990-2012. Information on CNS infection hospitalizations and pathogens was retrieved from national registries and laboratories. Incidence rates were estimated as cases per 100,000 person......-years. Incidence rate ratios were calculated using log-linear Poisson-regression. Mortality was estimated using Kaplan-Meier curves and Log Rank test. RESULTS: The incidence rate of CNS infections was twice as high in Greenland (35.6 per 100,000 person years) as in Denmark (17.7 per 100,000 person years...

  5. Water resource management in river oases along the Tarim River in North-West of China

    Science.gov (United States)

    Kliucininkaite, Lina; Disse, Markus

    2013-04-01

    Tarim River is one of the longest inland rivers in the world. It flows its water in the northern part of the Taklamakan desert in Xinjiang, North-west of China, which is a very hostile region due its climatic conditions and particularly due to low precipitation and very high evaporation rates. During the past five decades intensive exploitation of water resources, mainly by agricultural activities, has changed the temporal and spatial distribution of them and caused serious environmental problems in the Tarim River Basin. The support measures for oasis management along the Tarim River under climatic and societal changes became the overarching goal of this research. The temperature has risen by nearly 1° C over the past 50 years in the Tarim River Basin so more water was available in the mountainous areas of Xinjiang, leading to an increasing trend of the headstream discharges of the Tarim Basin. Aksu, Hotan and Yarkant Rivers are three tributaries of the Tarim River, as well as its main water suppliers. However, under the condition of water increase with the volume of 25×108 m3 in headstreams in recent 10 years, the water to the mainstream has increased less than 108 m3 (in Alar hydrological station), which is less than 3% of the increased water volume of runoff. Moreover, the region is one of the biggest cotton and other cash crops producers in China. In addition, expansion of urban and, in particular, of irrigation areas have caused higher water consumption at different parts of the river, leading to severe ecological effects on rural areas, especially in the lower reaches. Moreover, it also highly affects groundwater level and quality. The aim of this research is to support decision makers, planners and engineers to find right measures in the area for the further development of the region, as well as adaptation to changing climate. Different scenarios for water resource management, as well as water distribution and allocation in a more efficient and water

  6. Degradation of water quality: the case of plain west of Annaba (northeast Algeria

    Directory of Open Access Journals (Sweden)

    Attoui Badra

    2016-12-01

    Full Text Available In the world, the water quality is undergoing deterioration due to urban and industrial wastes, and intensive use of chemical fertilizers in agriculture. Unfortunately, as in most countries of the world, Algeria is experiencing a severe crisis of its environment apart from the problem of depletion of water resources. The plain west of Annaba is particularly subjected to a general industrial pollution. The pollution problem in this region has really started to become worrying not earlier than in 1980, when the economic crisis has led some industrial units to sacrifice the “Environment” criterion for the benefit of the production. We were particularly interested in this work in waters of the superficial aquifer and wadis like Boudjemaa, Bouhdid, Sidi Harb, and Forcha whose waters are most often used to irrigate the surrounding agricultural land. Comparison of analytical results from two periods – 2006–2016 for the: EC, pH, Ca2+, Mg2+, Cl−, NO2 and 2006–2010 for the: Fe, Cr, Cu2+, Pb+ show a degradation of water quality in this region, which represents a very vulnerable area with a risk to pollution of groundwater.

  7. China and Greenland

    DEFF Research Database (Denmark)

    Jakobsen, Uffe

    2014-01-01

    More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland......More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland...

  8. The Chlordecone crisis in the French West Indies : Its fate in soils and water

    Science.gov (United States)

    Voltz, Marc; Cattan, Philippe; Saison, Carine; Berns, Anne E.; Colin, François; Crabit, Armand; Crevoisier, David; Fernandez-Bayo, Jesus; Levillain, Joseph; Pak, Lai-Ting; Samouelian, Anatja; Cabidoche, Yves-Marie

    2013-04-01

    In the French West Indies, chlordecone (CLD), an organochlorine pesticide, which is highly persistent in the environment, was applied in banana plantations from 1972 to 1993 against the banana weevil Cosmopolites sordidus. Pollution surveys conducted in 2001 by the French Department of Health revealed the presence of chlordecone in soils, rivers, springs over large areas in Guadeloupe and Martinique islands. Contamination of drinking water, food crops, aquatic species by CLD has been observed as well as its presence in blood of men, pregnant women and newborns. There is therefore a large social concern about the extent and evolution of CLD pollution in the French West Indies and its impact on human health and ecosystems. From 2008 to 2012 a multidisciplinary project CHLORDEXCO took place to study the CLD fate in water, soils and the contamination characteristics of aquatic species and food crops. Here, we summarize results obtained on the processes controlling the spatial and temporal patterns of soil and water contamination at the scale of the banana cropping area in Guadeloupe and of the Perou catchment. The main soils in the contaminated areas are andosols and nitisols and formed from the weathering of volcanic ashes. They have a high organic carbon content and high content of secondary minerals, allophane for andosols and halloysite for nitisols. An analysis of the spatial distribution of CLD in soil over 1045 field plots showed that the soil type had a strong impact. Andosols, with a high sorption capacity (Koc 20 000 L/kg), had the highest CLD concentrations and stocks, unlike Nitisols, which had 10-fold lower sorption capacities. A significant « farm effect », due to between-farm variations of application times and amounts, was also noticed. The observed stocks of CLD clearly correspond to the accumulation in soil of successive treatments and thereby confirm the high persistence of CLD in soil also observed in incubation studies in soil microcosms. Soil

  9. Surface-water radon-222 distribution along the west-central Florida shelf

    Science.gov (United States)

    Smith, C.G.; Robbins, L.L.

    2012-01-01

    In February 2009 and August 2009, the spatial distribution of radon-222 in surface water was mapped along the west-central Florida shelf as collaboration between the Response of Florida Shelf Ecosystems to Climate Change project and a U.S. Geological Survey Mendenhall Research Fellowship project. This report summarizes the surface distribution of radon-222 from two cruises and evaluates potential physical controls on radon-222 fluxes. Radon-222 is an inert gas produced overwhelmingly in sediment and has a short half-life of 3.8 days; activities in surface water ranged between 30 and 170 becquerels per cubic meter. Overall, radon-222 activities were enriched in nearshore surface waters relative to offshore waters. Dilution in offshore waters is expected to be the cause of the low offshore activities. While thermal stratification of the water column during the August survey may explain higher radon-222 activities relative to the February survey, radon-222 activity and integrated surface-water inventories decreased exponentially from the shoreline during both cruises. By estimating radon-222 evasion by wind from nearby buoy data and accounting for internal production from dissolved radium-226, its radiogenic long-lived parent, a simple one-dimensional model was implemented to determine the role that offshore mixing, benthic influx, and decay have on the distribution of excess radon-222 inventories along the west Florida shelf. For multiple statistically based boundary condition scenarios (first quartile, median, third quartile, and maximum radon-222 inshore of 5 kilometers), the cross-shelf mixing rates and average nearshore submarine groundwater discharge (SGD) rates varied from 100.38 to 10-3.4 square kilometers per day and 0.00 to 1.70 centimeters per day, respectively. This dataset and modeling provide the first attempt to assess cross-shelf mixing and SGD on such a large spatial scale. Such estimates help scale up SGD rates that are often made at 1- to 10-meter

  10. A social epidemiological aspect of the Greenlandic part of Inuit Health in Transition

    DEFF Research Database (Denmark)

    Pedersen, Cecilia Petrine

    part of the cross-sectional population survey Inuit Health in Transition collected from 2005 to 2007. 2246 participants in towns and villages in West Greenland answered a questionnaire. Descriptive statistical analysis of suicidal behaviour (suicide ideation, suicide attempts and suicide among family......A social epidemiology aspect of Inuit Health in Transition Cecilia Petrine Pedersen, National Institute of Public Health, Copenhagen, Denmark Purpose: Greenland has a sad record of high suicide rates - especially among young men, and social neglect in the form of alcohol abuse in the childhood home......, sexual assaults and violence is a part of life for many people in Greenland. The purpose of this study is to draw a picture of social and mental health conditions in Greenland today among adult men and women by looking at suicidal behaviour and social neglect. Methods: Data is based on the Greenlandic...

  11. Hydrogeologic Setting and Ground-Water Flow in the Leetown Area, West Virginia

    Science.gov (United States)

    Kozar, Mark D.; Weary, David J.; Paybins, Katherine S.; Pierce, Herbert A.

    2007-01-01

    The Leetown Science Center is a research facility operated by the U.S. Geological Survey that occupies approximately 455-acres near Kearneysville, Jefferson County, West Virginia. Aquatic and fish research conducted at the Center requires adequate supplies of high-quality, cold ground water. Three large springs and three production wells currently (in 2006) supply water to the Center. The recent construction of a second research facility (National Center for Cool and Cold Water Aquaculture) operated by the U.S. Department of Agriculture and co-located on Center property has placed additional demands on available water resources in the area. A three-dimensional steady-state finite-difference ground-water flow model was developed to simulate ground-water flow in the Leetown area and was used to assess the availability of ground water to sustain current and anticipated future demands. The model also was developed to test a conceptual model of ground-water flow in the complex karst aquifer system in the Leetown area. Due to the complexity of the karst aquifer system, a multidisciplinary research study was required to define the hydrogeologic setting. Geologic mapping, surface- and borehole-geophysical surveys, stream base-flow surveys, and aquifer tests were conducted to provide the hydrogeologic data necessary to develop and calibrate the model. It would not have been possible to develop a numerical model of the study area without the intensive data collection and methods developments components of the larger, more comprehensive hydrogeologic investigation. Results of geologic mapping and surface-geophysical surveys verified the presence of several prominent thrust faults and identified additional faults and other complex geologic structures (including overturned anticlines and synclines) in the area. These geologic structures are known to control ground-water flow in the region. Results of this study indicate that cross-strike faults and fracture zones are major

  12. U.S. Navy Regional Climatic Study of the Greenland-Iceland-United Kingdom Gap and Associated Waters

    Science.gov (United States)

    1992-02-01

    Associated Waters 6. AUTHOR(S) William A. Brower, Jr., William 0. Brown, Ronald G. Baldwin, and Phala L. Franks 7. PERFORMING ORGANIZATION NAME(S) AND...meteorologists of the NCDC’s Global Climate Laboratory (GCL): William A. Brower, Jr., for serving as project leader and chief climatic analyst; William 0. Brown...ITOTI REAN NO. OF DAYS 4ITR (LI EANS I EATAEREIPERCENTIPP IP.I ALTI I I𔄂𔃻 TEMP IDEG F, I PRECIPITATION i OBSTR TO VISION I I I I ILST1 I.4.1 I

  13. Physico-chemical characterization of surface waters of the west coast of Algeria: Bay of Mostaganem and Cheliff estuary

    OpenAIRE

    Fatima Kies; Ahmed Kerkouf

    2014-01-01

    A follow-up in 2013 of the indicators of pollution (temperature, hydrogen potential, salinity, dissolved oxygen, ammonium, nitrites, nitrates, orthophosphates, ortho silicates, biological oxygen demand, chemical oxygen demand, suspended solids) in surface water was performed, in order to estimate the physicochemical quality of the west coast of Algeria. The results obtained revealed the existence of a water contamination by domestic and industrial waste water conveyed to the north by the Chel...

  14. A spatial and seasonal assessment of river water chemistry across North West England.

    Science.gov (United States)

    Rothwell, J J; Dise, N B; Taylor, K G; Allott, T E H; Scholefield, P; Davies, H; Neal, C

    2010-01-15

    This paper presents information on the spatial and seasonal patterns of river water chemistry at approximately 800 sites in North West England based on data from the Environment Agency regional monitoring programme. Within a GIS framework, the linkages between average water chemistry (pH, sulphate, base cations, nutrients and metals) catchment characteristics (topography, land cover, soil hydrology, base flow index and geology), rainfall, deposition chemistry and geo-spatial information on discharge consents (point sources) are examined. Water quality maps reveal that there is a clear distinction between the uplands and lowlands. Upland waters are acidic and have low concentrations of base cations, explained by background geological sources and land cover. Localised high concentrations of metals occur in areas of the Cumbrian Fells which are subjected to mining effluent inputs. Nutrient concentrations are low in the uplands with the exception sites receiving effluent inputs from rural point sources. In the lowlands, both past and present human activities have a major impact on river water chemistry, especially in the urban and industrial heartlands of Greater Manchester, south Lancashire and Merseyside. Over 40% of the sites have average orthophosphate concentrations >0.1mg-Pl(-1). Results suggest that the dominant control on orthophosphate concentrations is point source contributions from sewage effluent inputs. Diffuse agricultural sources are also important, although this influence is masked by the impact of point sources. Average nitrate concentrations are linked to the coverage of arable land, although sewage effluent inputs have a significant effect on nitrate concentrations. Metal concentrations in the lowlands are linked to diffuse and point sources. The study demonstrates that point sources, as well as diffuse sources, need to be considered when targeting measures for the effective reduction in river nutrient concentrations. This issue is clearly important

  15. Fluoride Content of Bottled Drinking Water Available in North West of Iran

    Directory of Open Access Journals (Sweden)

    Reza Fouladi Fard

    2015-06-01

    Full Text Available Background: Consumption of bottled waters has received popularity and more acceptances. Fluoride is necessary for human life. But high levels of fluoride can cause some problems for human health such as Fluorosis and teeth and bones problems. The aim of this study is measure the fluoride content in bottled waters consumed in North West of Iran and comparison with the amount listed on their labels and with the drinking water standards. Methods: In this study, 10 brands of bottled water were sampled from markets over the two seasons randomly. Samples were analyzed for fluoride using Ion Chromatography (IC method. Results: Results showed that fluoride concentration in different brands had a significant difference (P <0.05. The concentration of fluoride in samples ranged between 0.04 and 0.32 mg/L. Among analyzed selected brands four brands were observed significant differences with the measured values. Conclusion:  Totally the measured values didn’t match with the values declared on the labels (Reliability coefficient <0. It was revealed that fluoride concentration in all brands was less than the lower range of Iranian national standard (0.7-1.2 mg/lit.

  16. Water resources on the Pueblo of Laguna, west-central New Mexico

    Science.gov (United States)

    Risser, D.W.; Lyford, F.P.

    1983-01-01

    This study evaluates the quality and quantity of water available on the Pueblo of Laguna, New Mexico. Groundwater for public supply occurs in the valley fill along the Rio San Jose, in the Paguate and Encinal areas, and possibly in the northern part of the Sedillo Grant. The valley fill in the Rio San Jose will supply 50 to 450 gallons per minute of potable water to properly constructed wells. In the alluvium along Rio Paguate, additional development of as much as 250 gallons per minute is possible. Groundwater for irrigation is restricted by available yields and quality to the valley fill along the Rio San Jose and possibly the western part of the Major 's Ranch area. In the Rio San Jose valley yields of 50 to 450 gallons per minute of water containing 500 to 3,000 milligrams per liter are possible. Digital-model simulations of the valley-fill aquifer west of the Village of Laguna show a potential salvage of as much as 900 acre-feet per year of evapotranspiration losses if water levels are lowered. Model studies also indicate that the winter flow of the Rio San Jose could be used to recharge groundwater stored in the valley. (USGS)

  17. Modelling the impacts of projected future climate change on water resources in north-west England

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Over the last two decades, the frequency of water resource drought in the UK, coupled with the more recent pan-European drought of 2003, has increased concern over changes in climate. Using the UKCIP02 Medium-High (SRES A2 scenario for 2070–2100, this study investigates the impact of climate change on the operation of the Integrated Resource Zone (IRZ, a complex conjunctive-use water supply system in north-western England. The results indicate that the contribution of individual sources to yield may change substantially but that overall yield is reduced by only 18%. Notwithstanding this significant effect on water supply, the flexibility of the system enables it to meet modelled demand for much of the time under the future climate scenario, even without a change in system management, but at significant expense for pumping additional abstraction from lake and borehole sources. This research provides a basis for the future planning and management of the complex water resource system in the north-west of England.

  18. West Antarctic Ice Sheet retreat driven by Holocene warm water incursions

    Science.gov (United States)

    Hillenbrand, Claus-Dieter; Smith, James A.; Hodell, David A.; Greaves, Mervyn; Poole, Christopher R.; Kender, Sev; Williams, Mark; Andersen, Thorbjørn Joest; Jernas, Patrycja E.; Elderfield, Henry; Klages, Johann P.; Roberts, Stephen J.; Gohl, Karsten; Larter, Robert D.; Kuhn, Gerhard

    2017-07-01

    Glaciological and oceanographic observations coupled with numerical models show that warm Circumpolar Deep Water (CDW) incursions onto the West Antarctic continental shelf cause melting of the undersides of floating ice shelves. Because these ice shelves buttress glaciers feeding into them, their ocean-induced thinning is driving Antarctic ice-sheet retreat today. Here we present a multi-proxy data based reconstruction of variability in CDW inflow to the Amundsen Sea sector, the most vulnerable part of the West Antarctic Ice Sheet, during the Holocene epoch (from 11.7 thousand years ago to the present). The chemical compositions of foraminifer shells and benthic foraminifer assemblages in marine sediments indicate that enhanced CDW upwelling, controlled by the latitudinal position of the Southern Hemisphere westerly winds, forced deglaciation of this sector from at least 10,400 years ago until 7,500 years ago—when an ice-shelf collapse may have caused rapid ice-sheet thinning further upstream—and since the 1940s. These results increase confidence in the predictive capability of current ice-sheet models.

  19. The spectral optical properties and relative radiant heating contribution of dissolved and particulate matter in the surface waters across the Fram Strait

    DEFF Research Database (Denmark)

    Pavlov, A.K.; Granskog, M.A.; Stedmon, Colin

    The Fram Strait is the key region for exchange processes between Arctic Ocean and North Atlantic. With two major near-surface currents, the warm and salty West Spitsbergen Current and cold low-salinity East Greenland Current, its waters encompass two distinct oceanographic environments. During...

  20. The spectral optical properties and relative radiant heating contribution of dissolved and particulate matter in the surface waters across the Fram Strait

    DEFF Research Database (Denmark)

    Pavlov, A.K.; Granskog, M.A.; Stedmon, Colin

    The Fram Strait is the key region for exchange processes between Arctic Ocean and North Atlantic. With two major near-surface currents, the warm and salty West Spitsbergen Current and cold low-salinity East Greenland Current, its waters encompass two distinct oceanographic environments. During...

  1. GIS-Based Evaluation of Water Quality Index of Ground Water Resources in West Bokaro Coalfield, India

    Directory of Open Access Journals (Sweden)

    Ashwani Kumar Tiwari

    2014-12-01

    Full Text Available Water Quality Index (WQI, a technique of rating water quality, is an effective tool to assess quality and ensure sustainable safe use of water for drinking. The present work is aimed to assess the groundwater quality of West Bokaro coalfield region for knowing the suitability of drinking purpose by calculating the WQI and using Geographical Information System (GIS techniques. Thirty three groundwater samples were collected from dug wells during post-monsoon, 2012 for comprehensive physico-chemical analysis. Ten parameters were considered for calculating the WQI such as: pH, fluoride (F-, chloride (Cl-, nitrate (NO3-, sulphate(SO42-, bicarbonate (HCO3- calcium(Ca2+, magnesium (Mg2+, total hardness (TH and total dissolved solid (TDS. The spatial distribution maps of the above mentioned parameters were prepared by using GIS, software. The computed WQI value ranges from 21 to 131 with an overall average of WQI value 73. More than half of the locations fall in Excellent to Good category indicating the ground water in the study area is suitable for drinking purposes.

  2. The Greenland Ramsar Sites

    DEFF Research Database (Denmark)

    Egevang, C.; Boertmann, D.

    The eleven Ramsar sites in Greenland are reviewed in terms of their status as habitats for waterbirds and other fauna. Management and monitoring is proposed, as well as revisions of their boundaries. A number of potential new Ramsar sites are described...

  3. China and Greenland

    DEFF Research Database (Denmark)

    Jakobsen, Uffe

    2014-01-01

    More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland...

  4. How Greenland melts

    NARCIS (Netherlands)

    van den Broeke, M.R.

    2010-01-01

    Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that

  5. How Greenland melts

    NARCIS (Netherlands)

    van den Broeke, M.R.

    2010-01-01

    Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that

  6. Commentary: Future Greenland 2015

    DEFF Research Database (Denmark)

    Bjørst, Lill Rastad

    2015-01-01

    Every second year the Greenlandic Business Association host the two-day conference “Future Greenland” in Nuuk. The main theme of this year conference was “Growth and welfare – scenarios for the development of Greenland”. The conference had more than 400 participants - mostly from Denmark and Gree...

  7. Inuit health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, P; Curtis, T; Borch-Johnsen, K

    2003-01-01

    specimens (blood, urine, subcutaneous fat tissue). The clinical examinations included anthropometric measurements, an oral glucose tolerance test, ECG, ultrasound of thyroid gland and carotid arteries, a skin prick test, and lung function. The data collection areas in Greenland ranged from the westernized...

  8. APISSEQ Sisimiut – Greenland

    DEFF Research Database (Denmark)

    Kotol, Martin

    This report summarizes the very first survey of the engineering dormitory Apisseq in Sisimiut, Greenland. The dormitory was inaugurated in August 2010 and the survey was performed in March 2011. The experienced problems and their possible causes are explained in the report. Furthermore possible...

  9. Generating synthetic fjord bathymetry for coastal Greenland

    Science.gov (United States)

    Williams, Christopher N.; Cornford, Stephen L.; Jordan, Thomas M.; Dowdeswell, Julian A.; Siegert, Martin J.; Clark, Christopher D.; Swift, Darrel A.; Sole, Andrew; Fenty, Ian; Bamber, Jonathan L.

    2017-02-01

    Bed topography is a critical boundary for the numerical modelling of ice sheets and ice-ocean interactions. A persistent issue with existing topography products for the bed of the Greenland Ice Sheet and surrounding sea floor is the poor representation of coastal bathymetry, especially in regions of floating ice and near the grounding line. Sparse data coverage, and the resultant coarse resolution at the ice-ocean boundary, poses issues in our ability to model ice flow advance and retreat from the present position. In addition, as fjord bathymetry is known to exert strong control on ocean circulation and ice-ocean forcing, the lack of bed data leads to an inability to model these processes adequately. Since the release of the last complete Greenland bed topography-bathymetry product, new observational bathymetry data have become available. These data can be used to constrain bathymetry, but many fjords remain completely unsampled and therefore poorly resolved. Here, as part of the development of the next generation of Greenland bed topography products, we present a new method for constraining the bathymetry of fjord systems in regions where data coverage is sparse. For these cases, we generate synthetic fjord geometries using a method conditioned by surveys of terrestrial glacial valleys as well as existing sinuous feature interpolation schemes. Our approach enables the capture of the general bathymetry profile of a fjord in north-west Greenland close to Cape York, when compared to observational data. We validate our synthetic approach by demonstrating reduced overestimation of depths compared to past attempts to constrain fjord bathymetry. We also present an analysis of the spectral characteristics of fjord centrelines using recently acquired bathymetric observations, demonstrating how a stochastic model of fjord bathymetry could be parameterised and used to create different realisations.

  10. Continuous broadband seismic observation on the Greenland Ice Sheet under Greenland Ice Sheet monitoring Network

    Science.gov (United States)

    Tsuboi, Seiji; Kanao, Masaki; Tono, Yoko; Himeno, Tetsuto; Toyokuni, Genti; Childs, Dean; Dahl-Jensen, Trine; anderson, Kent

    2013-04-01

    We have installed the ice sheet broadband seismograph station, called ICE-S (DK.ICESG) in June 2011, in collaboration with IRIS Polar Services under the GreenLand Ice Sheet monitoring Network (GLISN), which is a new, international, broadband seismic capability for Greenland being implemented through the collaboration between Denmark, Canada, France, Germany, Italy, Japan, Norway, Poland, Switzerland, and the USA. The primary purpose of GLISN project is to define the fine structure and detailed mechanisms of glacial earthquakes within the Greenland Ice Sheet. These glacial earthquakes in the magnitude range 4.6-5.1 may be modeled as a large glacial ice mass sliding downhill several meters on its basal surface over duration of 30 to 60 seconds. Glacial earthquakes have been observed at seismic stations within Greenland (Larsen et al, 2006), but the coverage was very sparse and a broadband, real-time seismic network was needed to be installed throughout Greenland's Ice Sheet and perimeter. The National Institute for Polar Research and Japan Agency for Marine-Earth Science and Technology are members of GLISN project and we have started to operate ICESG station since 2011. The station is equipped with a CMG-3T broadband seismometer and a Quanterra Q330 data logger. We have visited the station again in May, 2012 and successfully retrieved one year of continuous records from the broadband seismometer and updated the telemetry system to eventually allow real time monitoring of the station. ICESG station is now daily sending 1 Hz continuous data over the iridium satellite system using RUDICS. The observed three component seismograms demonstrate that the quality of this ice sheet station is good enough to record not only local earthquakes around Greeland but also teleseismic earthquakes. We could record three component broadband seismograms for April 11, 2012 Off the west coast of Northern Sumatra earthquake (Mw8.6). These seismograms show high signal to noise ratio

  11. Assessment of volatile organic compounds in surface water at West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 1999

    Science.gov (United States)

    Olsen, Lisa D.; Spencer, Tracey A.

    2000-01-01

    The U.S. Geological Survey (USGS) collected 13 surface-water samples and 3 replicates from 5 sites in the West Branch Canal Creek area at Aberdeen Proving Ground from February through August 1999, as a part of an investigation of ground-water contamination and natural attenuation processes. The samples were analyzed for volatile organic compounds, including trichloroethylene, 1,1,2,2-tetrachloroethane, carbon tetrachloride, and chloroform, which are the four major contaminants that were detected in ground water in the Canal Creek area in earlier USGS studies. Field blanks were collected during the sampling period to assess sample bias. Field replicates were used to assess sample variability, which was expressed as relative percent difference. The mean variability of the surface-water replicate analyses was larger (35.4 percent) than the mean variability of ground-water replicate analyses (14.6 percent) determined for West Branch Canal Creek from 1995 through 1996. The higher variability in surface-water analyses is probably due to heterogeneities in the composition of the surface water rather than differences in sampling or analytical procedures. The most frequently detected volatile organic compound was 1,1,2,2- tetrachloroethane, which was detected in every sample and in two of the replicates. The surface-water contamination is likely the result of cross-media transfer of contaminants from the ground water and sediments along the West Branch Canal Creek. The full extent of surface-water contamination in West Branch Canal Creek and the locations of probable contaminant sources cannot be determined from this limited set of data. Tidal mixing, creek flow patterns, and potential effects of a drought that occurred during the sampling period also complicate the evaluation of surface-water contamination.

  12. Statistical analysis of nitrate in ground water, West Salt River Valley, Arizona

    Science.gov (United States)

    Long, Andy E.; Brown, James G.; Gellenbeck, Dorinda J.

    1997-01-01

    Accurate estimates of the nitrate concentrations in ground water in west Salt River Valley are needed to better manage ground water affected by nitrate. Statistical analyses were done to establish the best statistical method to produce these estimates. Three sets of ground-water data for different time periods --1975-77, 1980-85, and 1986-90--were used to analyze spatial and temporal variations in concentrations of nitrate in ground water. The use of inverse-distance squared weighting, radial-basis function, kriging, and cokriging were evaluated for estimating nitrate concentrations in ground water. From an analysis of the cross-validation results, cokriging maps resulted in the best estimates, and they were accepted as being the most reliable. Cross-validation results also indicated that nitrate cokriged best with magnesium for 1975-77 and 1986-90 and with calcium for 1980-85. Kriging results consistently were almost as reliable as any of the cokriging results. Because of the difficulties inherent in the cokriging process, kriging, although not optimal, was the fastest way to obtain reasonably good results. In 1980-85, cokriged nitrate concentrations exceeded 20 milligrams per liter in a 12-square-kilometer area in Phoenix and Glendale and exceeded 10 milligrams per liter in a 280-square-kilometer area that extended to the Salt River. In 1986-90, nitrate concentrations along the entire reach of the Salt River in west Salt River Valley were less than 10 milligrams per liter and were smaller probably as a result of recharge from the Salt and Gila Rivers in 1982. Farther north in Phoenix and Glendale, the area in which nitrate concentrations exceeded 10 milligrams per liter expanded to 490 square kilometers for 1986-90. In Buckeye Valley, nitrate concentrations exceeded 10 milligrams per liter in an area of 300 square milometers for 1980-85 from the Gila River in the early 1980's but possibly could be an artifact of the different data distributions associated with

  13. The July 2016 Study of the water VApour in the polar AtmosPhere (SVAAP) campaign at Thule, Greenland: surface radiation budget and role of clouds

    Science.gov (United States)

    Meloni, Daniela; Di Iorio, Tatiana; di Sarra, Alcide; Iaccarino, Antonio; Pace, Giandomenico; Mevi, Gabriele; Muscari, Giovanni; Cacciani, Marco; Gröbner, Julian

    2017-04-01

    The Study of the water VApour in the polar AtmosPhere (SVAAP) project, funded by the Italian Programme for Antarctic Research, is aimed at investigating the surface radiation budget (SRB), the variability of atmospheric water vapour, and the long-term variations in stratospheric composition and structure at Thule, Greenland, in the framework of the international Network for Detection of Atmospheric Composition Change (NDACC). Thule High Arctic Atmospheric Observatory (THAAO, 76.5° N, 68.8° W) is devoted to study climate change and has been operational since 1990, with the contribution of different international institutions: DMI, NCAR, ENEA, INGV, Universities of Roma and Firenze (http://www.thuleatmos-it.it). As part of SVAAP an intensive field campaign was held at Thule from 5 to 28 July 2016. The campaign was also aimed at supporting the installation of VESPA-22, a new microwave radiometer for water vapour profiling in the upper atmosphere and integrated water vapour (IWV), and offered the possibility to study the cloud physical and optical properties and their impact on the SRB. Measurements of downward shortwave (SW) and longwave (LW) irradiance were already available since 2009. Additional observations were added to obtain the SRB and to characterize the atmospheric state: upward SW and LW irradiance, upwelling and downwelling photosynthetically active radiation (PAR), downward irradiance in the 8-14 µm infrared window, temperature and relative humidity tropospheric profiles, IWV, liquid water path (LWP), lidar tropospheric backscattering profiles, sky brightness temperature (BT) in the 9.6-11.5 µm spectral range, visible and infrared sky images, surface meteorological parameters. Moreover, 23 radiosonde were launched during the campaign. Data from the period 14-28 July are presented in this study. The first part of the campaign was characterized by stable cloud-free conditions, while alternation of cloudy and cloud-free sky occurred after 18 July. The

  14. A water sustainability index for West Java - Part 2: refining the conceptual framework using Delphi technique.

    Science.gov (United States)

    Juwana, I; Perera, B J C; Muttil, N

    2010-01-01

    In the first paper of this two-part series on the development of a water sustainability index for West Java, a conceptual framework of West Java Water Sustainability Index (WJWSI) was developed. It consists of three main parts: components, indicators/sub-indicators and threshold values. This second paper of the series presents the application of the Delphi technique, followed by in-depth interviews with selected key experts, to refine the conceptual WJWSI framework. The Delphi application includes the design of the questionnaires, the selection of respondents, the distribution and collection of the completed questionnaires and the analysis of data. After Round One of the Delphi application, the respondents reached consensus for all proposed components in the conceptual framework. However, some modifications to the components were also suggested by few respondents. Regarding the indicators/sub-indicators, consensus for 9 of the proposed 12 indicators was reached, and 5 new indicators were suggested. For the threshold values, consensus was reached for threshold values of 5 indicators. In Round Two of the Delphi application, respondents were asked questions related to results from Round One, which include the modification on the components, indicators/sub-indicators which have not been agreed, and newly suggested indicators/sub-indicators and threshold values. Results of Round Two show that modifications on the components were agreed, and consensus was reached for 8 out of the proposed 9 indicators/sub-indicators. In terms of its components and indicators, the framework was then finalised in the in-depth interview with four key experts, selected from different respondent categories. For the threshold values not yet finalised, further study will be carried out, as there was not much input from the respondents in the Delphi application and the in-depth interview.

  15. Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period

    DEFF Research Database (Denmark)

    Blunier, T; Brook, E J

    2001-01-01

    A precise relative chronology for Greenland and West Antarctic paleotemperature is extended to 90,000 years ago, based on correlation of atmospheric methane records from the Greenland Ice Sheet Project 2 and Byrd ice cores. Over this period, the onset of seven major millennial-scale warmings....... This pattern provides further evidence for the operation of a "bipolar see-saw" in air temperatures and an oceanic teleconnection between the hemispheres on millennial time scales....

  16. MIZEX. A Program for Mesoscale Air-Ice-Ocean Interaction Experiments in Arctic Marginal Ice Zones. II. A Science Plan for a Summer Marginal Ice Zone Experiment in the Fram Strait/Greenland Sea: 1984.

    Science.gov (United States)

    1983-05-01

    salinity, southward-flowing East Greenland Current from the more saline water in the Greenland Sea; or more transient, such as ice edge meltwater fronts... meltwater fronts) in the Fram Strait and Greenland Sea marginal ice zones? What is their temporal and spatial variability over a period of days? What is...three-dimensional structure of the fronts (East Greenland polar front and meltwater fronts) in the Fram Strait- Greenland Sea MIZ, their short-period

  17. The bottom water exchange between the Singapore Strait and the West Johor Strait

    Science.gov (United States)

    Sun, Yunfang; Eltahir, Elfatih; Malanotte-Rizzoli, Paola

    2017-08-01

    As a part of the border between Singapore and Malaysia, the West Johor Strait (WJS) suffered newly from harmful algal blooms. There is no previous study showing the source of the nutrients in the WJS. This paper is investigating the possible water exchange between the water in the WJS and the bottom water in Singapore Strait. This paper adopts a two-level nesting atmosphere-ocean coupled models to downscale the global atmosphere-ocean model into the Singapore coastal water, keeping the large-scale and long-term ocean and climate circulation signals and the advantages of the high-resolution. Based on the high-resolution ocean circulation fields, a Lagrangian particle tracking model is used to trace the Singapore Strait's bottom water movement and the water mixing in the WJS. The results showed that the numerical models well resolved the Singapore coastal water regional circulation. There is a small but significant bottom water (1.25%) transport from the Singapore Strait to the WJS, which occurs from the southwest coastline of Singapore. The bottom water in the Singapore Strait prefers to enter the WJS during the spring tide and the flood period, and stay in Johor Strait for 6.4 days. The spring tide is the first-order factor for the water vertical mixing in the WJS, the wind is also very important for the vertical mixing especially in neap tide condition. An overall very important factor is the light perturbation. With the strongest vertical mixing of nutrients and bottom sediments due to the spring tide, the latter ones may inhibit the light penetration during the spring tide and reduce the algal bloom. The light penetration otherwise is greater during the neap tide, when the winds are the most important factor and hence favor the algal bloom. With the strongest wind in February and the longest permanence time in June and the sufficient nutrient supply in February and June, the most serious algal blooms may happen in February and June in the WJS.

  18. Contrasting evidence of Holocene ice margin retreat, south-western Greenland

    DEFF Research Database (Denmark)

    Levy, L. B.; Larsen, N. K.; Davidson, T. A.

    2017-01-01

    Constraining the Greenland Ice Sheet's (GrIS) response to Holocene climate change provides calibrations for ice sheet models that hindcast past ice margin fluctuations. Ice sheet models predict enhanced ice retreat in south-western Greenland during the middle Holocene; however, few geological...... observations corroborating the extensive retreat are available. We present new data from lake sediment cores from the Isua region, south-western Greenland, which provide constraints on Holocene fluctuations of the GrIS margins. Our data indicate that the main GrIS margin was 30 km west of its present...

  19. Waves in shallow water off west coast of India during the onset of summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Philip, C.S.; Nair, T.N.B.

    and south-west and the balance was due to the seas from south-west to north-west. Wave age of the measured data indicates that the measured waves are young sea with presence of swells. Even when the wind speed reduced to less than 3 m/s, significant wave...

  20. High export of dissolved silica from the Greenland Ice Sheet

    Science.gov (United States)

    Meire, L.; Meire, P.; Struyf, E.; Krawczyk, D. W.; Arendt, K. E.; Yde, J. C.; Juul Pedersen, T.; Hopwood, M. J.; Rysgaard, S.; Meysman, F. J. R.

    2016-09-01

    Silica is an essential element for marine life and plays a key role in the biogeochemistry of the ocean. Glacial activity stimulates rock weathering, generating dissolved silica that is exported to coastal areas along with meltwater. The magnitude of the dissolved silica export from large glacial areas such as the Greenland Ice Sheet is presently poorly quantified and not accounted for in global budgets. Here we present data from two fjord systems adjacent to the Greenland Ice Sheet which reveal a large export of dissolved silica by glacial meltwater relative to other macronutrients. Upscaled to the entire Greenland Ice Sheet, the export of dissolved silica equals 22 ± 10 Gmol Si yr-1. When the silicate-rich meltwater mixes with upwelled deep water, either inside or outside Greenland's fjords, primary production takes place at increased silicate to nitrate ratios. This likely stimulates the growth of diatoms relative to other phytoplankton groups.