WorldWideScience

Sample records for arctic vegetation types

  1. Radiation budget and soil heat fluxes in different Arctic tundra vegetation types

    Science.gov (United States)

    Juszak, Inge; Iturrate Garcia, Maitane; Gastellu-Etchegorry, Jean-Philippe; Schaepman, Michael E.; Schaepman-Strub, Gabriela

    2016-04-01

    While solar radiation is one of the primary energy sources for warming and thawing permafrost soil, the amount of shortwave radiation reaching the soil is reduced by vegetation shading. Climate change has led to greening, shrub expansion and encroachment in many Arctic tundra regions and further changes are anticipated. These vegetation changes feed back to the atmosphere and permafrost as they modify the surface energy budget. However, canopy transmittance of solar radiation has rarely been measured or modelled for a variety of tundra vegetation types. We assessed the radiation budget of the most common vegetation types at the Kytalyk field site in North-East Siberia (70.8°N, 147.5°E) with field measurements and 3D radiative transfer modelling and linked it to soil heat fluxes. Our results show that Arctic tundra vegetation types differ in canopy albedo and transmittance as well as in soil heat flux and active layer thickness. Tussock sedges transmitted on average 56% of the incoming light and dwarf shrubs 27%. For wet sedges we found that the litter layer was very important as it reduced the average transmittance to only 6%. Model output indicated that both, albedo and transmittance, also depend on the spatial aggregation of vegetation types. We found that permafrost thaw was more strongly related to soil properties than to canopy shading. The presented radiative transfer model allows quantifying effects of the vegetation layer on the surface radiation budget in permafrost areas. The parametrised model can account for diverse vegetation types and variation of properties within types. Our results highlight small scale radiation budget and permafrost thaw variability which are indicated and partly caused by vegetation. As changes in species composition and biomass increase can influence thaw rates, small scale patterns should be considered in assessments of climate-vegetation-permafrost feedbacks.

  2. Accuracy assessment of airphoto interpretation of vegetation types and disturance levels on winter seismic trails, Arctic National Wildlife Refuge, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An accuracy assessment was conducted to evaluate the photo-interpretation of vegetation types and disturbance levels along seismic trails in the Arctic National...

  3. Use of High Resolution UAS Imagery to Classify Sub-Arctic Vegetation Types

    Science.gov (United States)

    Herrick, C.; Palace, M. W.; Finnell, D. R.; Garnello, A.; Sullivan, F.; Anderson, S. M.; Varner, R. K.

    2014-12-01

    Sub-arctic permafrost regions are now experiencing annual warming with a resulting thaw that induces changes to the vegetative landscape. This warming trend is directly correlated to increases in annual greenhouse gas emissions including methane (CH4). Vegetation species and composition are indirect indicators of CH4 flux, and may serve as a proxy for estimating changes in CH4emission over time. Three WorldView-2 images (2m2 spatial resolution, 8 multispectral bands) were acquired in Jul/Aug of 2012-2014 over the Abisko region in northern Sweden. Color infrared (CIR) sub-meter imagery was also collected over a 4km2 area in 2014 using both a multi-rotor helicopter and a fixed wing unmanned aircraft system (UAS). Fifty 1m2 ground sample plots were established; these plots cover 5 major ground cover vegetation classes and were used in classification efforts. Texture analysis was conducted on both UAS and WV-2 imagery. Both an unsupervised k-means clustering algorithm to predict vegetation classes and a supervised classification using both random forests and neural networks were conducted; similar texture analysis and clustering were also performed on the UAS imagery. Classifications of the two imagery types were compared with promising results, thus supporting the use of UAS and high resolution satellite image collection to provide landscape level characterization of vegetation.

  4. Diversification of Nitrogen Sources in Various Tundra Vegetation Types in the High Arctic.

    Science.gov (United States)

    Skrzypek, Grzegorz; Wojtuń, Bronisław; Richter, Dorota; Jakubas, Dariusz; Wojczulanis-Jakubas, Katarzyna; Samecka-Cymerman, Aleksandra

    2015-01-01

    Low nitrogen availability in the high Arctic represents a major constraint for plant growth, which limits the tundra capacity for carbon retention and determines tundra vegetation types. The limited terrestrial nitrogen (N) pool in the tundra is augmented significantly by nesting seabirds, such as the planktivorous Little Auk (Alle alle). Therefore, N delivered by these birds may significantly influence the N cycling in the tundra locally and the carbon budget more globally. Moreover, should these birds experience substantial negative environmental pressure associated with climate change, this will adversely influence the tundra N-budget. Hence, assessment of bird-originated N-input to the tundra is important for understanding biological cycles in polar regions. This study analyzed the stable nitrogen composition of the three main N-sources in the High Arctic and in numerous plants that access different N-pools in ten tundra vegetation types in an experimental catchment in Hornsund (Svalbard). The percentage of the total tundra N-pool provided by birds, ranged from 0-21% in Patterned-ground tundra to 100% in Ornithocoprophilous tundra. The total N-pool utilized by tundra plants in the studied catchment was built in 36% by birds, 38% by atmospheric deposition, and 26% by atmospheric N2-fixation. The stable nitrogen isotope mixing mass balance, in contrast to direct methods that measure actual deposition, indicates the ratio between the actual N-loads acquired by plants from different N-sources. Our results enhance our understanding of the importance of different N-sources in the Arctic tundra and the used methodological approach can be applied elsewhere.

  5. Arctic Tundra Vegetation Functional Types Based on Photosynthetic Physiology and Optical Properties

    Science.gov (United States)

    Huemmrich, Karl Fred; Gamon, John A.; Tweedie, Craig E.; Campbell, Petya K. Entcheva; Landis, David R.; Middleton, Elizabeth M.

    2013-01-01

    Non-vascular plants (lichens and mosses) are significant components of tundra landscapes and may respond to climate change differently from vascular plants affecting ecosystem carbon balance. Remote sensing provides critical tools for monitoring plant cover types, as optical signals provide a way to scale from plot measurements to regional estimates of biophysical properties, for which spatial-temporal patterns may be analyzed. Gas exchange measurements were collected for pure patches of key vegetation functional types (lichens, mosses, and vascular plants) in sedge tundra at Barrow, AK. These functional types were found to have three significantly different values of light use efficiency (LUE) with values of 0.013 plus or minus 0.0002, 0.0018 plus or minus 0.0002, and 0.0012 plus or minus 0.0001 mol C mol (exp -1) absorbed quanta for vascular plants, mosses and lichens, respectively. Discriminant analysis of the spectra reflectance of these patches identified five spectral bands that separated each of these vegetation functional types as well as nongreen material (bare soil, standing water, and dead leaves). These results were tested along a 100 m transect where midsummer spectral reflectance and vegetation coverage were measured at one meter intervals. Along the transect, area-averaged canopy LUE estimated from coverage fractions of the three functional types varied widely, even over short distances. The patch-level statistical discriminant functions applied to in situ hyperspectral reflectance data collected along the transect successfully unmixed cover fractions of the vegetation functional types. The unmixing functions, developed from the transect data, were applied to 30 m spatial resolution Earth Observing-1 Hyperion imaging spectrometer data to examine variability in distribution of the vegetation functional types for an area near Barrow, AK. Spatial variability of LUE was derived from the observed functional type distributions. Across this landscape, a

  6. Design and Development of a Spectral Library for Different Vegetation and Landcover Types for Arctic, Antarctic and Chihuahua Desert Ecosystem

    Science.gov (United States)

    Matharasi, K.; Goswami, S.; Gamon, J.; Vargas, S.; Marin, R.; Lin, D.; Tweedie, C. E.

    2008-12-01

    All objects on the Earth's surface absorb and reflect portions of the electromagnetic spectrum. Depending on the composition of the material, every material has its characteristic spectral profile. The characteristic spectral profile for vegetation is often used to study how vegetation patterns at large spatial scales affect ecosystem structure and function. Analysis of spectroscopic data from the laboratory, and from various other platforms like aircraft or spacecraft, requires a knowledge base that consists of different characteristic spectral profiles for known different materials. This study reports on establishment of an online and searchable spectral library for a range of plant species and landcover types in the Arctic, Anatarctic and Chihuahuan desert ecosystems. Field data were collected from Arctic Alaska, the Antarctic Peninsula and the Chihuahuan desert in the visible to near infrared (IR) range using a handheld portable spectrometer. The data have been archived in a database created using postgre sql with have been made publicly available on a plone web-interface. This poster describes the data collected in more detail and offers instruction to users who wish to make use of this free online resource.

  7. New views on changing Arctic vegetation

    Science.gov (United States)

    Kennedy, Robert E.

    2012-03-01

    ). While the USGS archive has been dominated by imagery from the United States, recent efforts by the USGS to repatriate data stored in international archives are adding new historical images to the archive every day. With persistence and the goodwill of collaborating countries, this effort may someday allow analyses similar to that of Fraser et al across broader expanses of the Earth, providing further insights into the mechanisms and manifestations of climate change. References Chapin F S et al 2000 Arctic and boreal ecosystems of western North America as components of the climate system Glob. Change Biol. 6 211-23 Coops N C and Waring R H 2011 A process-based approach to estimate lodgepole pine (Pinus contorta Dougl.) distribution in the Pacific Northwest under climate change Clim. Change 105 313-28 de Beurs K M and Henebry G M 2010 A land surface phenology assessment of the northern polar regions using MODIS reflectance time series Can. J. Remote Sens. 36 S87-110 Forbes B C, Fauria M M and Zetterberg P 2010 Russian Arctic warming and 'greening' are closely tracked by tundra shrub willows Glob. Change Biol. 16 1542-54 Fraser R H et al 2011 Detecting long-term changes to vegetation in northern Canada using the Landsat satellite image archive Environ. Res. Lett. 6 045502 Goodwin N R, Magnussen S, Coops N C and Wulder M A 2010 Curve fitting of time-series Landsat imagery for characterizing a mountain pine beetle infestation Int. J. Remote Sens. 31 3263-71 Hais M, Jonášová M, Langhammer J and Kuèera T 2009 Comparison of two types of forest disturbance using multitemporal Landsat TM/ETMC imagery and field vegetation data Remote Sens. Environ. 113 835-45 Hansen M C, Stehman S V and Potapov P V 2010 Quantification of global gross forest cover loss Proc. Natl Acad. Sci. 107 8650-5 Huang C, Goward S N, Masek J G, Thomas N, Zhu Z and Vogelmann J E 2010 An automated approach for reconstructing recent forest disturbance history using dense Landsat time series stacks Remote Sens

  8. The Alaska Arctic Vegetation Archive (AVA-AK)

    NARCIS (Netherlands)

    Walker, Donald A.; Breen, Amy L.; Druckenmiller, Lisa A.; Wirth, Lisa W.; Fisher, Will; Raynolds, Martha K.; Šibík, Jozef; Walker, Marilyn D.; Hennekens, Stephan; Boggs, Keith; Boucher, Tina; Buchhorn, Marcel; Bültmann, Helga; Cooper, David J.; Daniëls, Fred J.A.; Davidson, Scott J.; Ebersole, James J.; Elmendorf, Sara C.; Epstein, Howard E.; Gould, William A.; Hollister, Robert D.; Iversen, Colleen M.; Jorgenson, M.T.; Kade, Anja; Lee, Michael T.; MacKenzie, William H.; Peet, Robert K.; Peirce, Jana L.; Schickhoff, Udo; Sloan, Victoria L.; Talbot, Stephen S.; Tweedie, Craig E.; Villarreal, Sandra; Webber, Patrick J.; Zona, Donatella

    2016-01-01

    The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation dat

  9. Description of vegetation types

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document provides descriptions of five vegetation types found in Iowa- oak savannah, mature hardwoods, floodplain woods, scrub woods, and riparian woods. Oak...

  10. Expansion of vegetated coastal ecosystems in the future Arctic

    Directory of Open Access Journals (Sweden)

    Dorte eKrause-Jensen

    2014-12-01

    Full Text Available Warming occurs particularly fast in the Arctic and exerts profound effects on arctic ecosystems. Sea ice-associated ecosystems are projected to decline but reduced arctic sea ice cover also increases the solar radiation reaching the coastal seafloors with the potential for expansion of vegetated habitats, i.e. kelp forests and seagrass meadows. These habitats support key ecosystem functions, some of which may mitigate effects of climate change. Therefore, the likely expansion of vegetated coastal habitats in the Arctic will generate new productive ecosystems, offer habitat for a number of invertebrate and vertebrate species, including provision of refugia for calcifiers from possible threats from ocean acidification, contribute to enhance CO2 sequestration and protect the shoreline from erosion. The development of models allowing quantitative forecasts of the future of vegetated arctic ecosystems requires that key hypotheses underlying such forecasts be tested. Here we propose a set of three key testable hypotheses along with a research agenda for testing them using a broad diversity of approaches, including analyses of paleo-records, space for-time substitutions and experimental studies. The research agenda proposed would provide a solid underpinning to guide forecasts on the spread of marine macrophytes onto the Arctic with climate change and contribute to balance our understanding of climate change impacts on the arctic ecosystem through a focus on the role of engineering species. Anticipating these changes in ecosystem structure and function is key to develop managerial strategies to maximize these ecosystem services in a future warmer Arctic.

  11. Arctic Browning: vegetation damage and implications for carbon balance.

    Science.gov (United States)

    Treharne, Rachael; Bjerke, Jarle; Emberson, Lisa; Tømmervik, Hans; Phoenix, Gareth

    2016-04-01

    'Arctic browning' is the loss of biomass and canopy in Arctic ecosystems. This process is often driven by climatic and biological extreme events - notably extreme winter warm periods, winter frost-drought and severe outbreaks of defoliating insects. Evidence suggests that browning is becoming increasingly frequent and severe at the pan-arctic scale, a view supported by observations from more intensely observed regions, with major and unprecedented vegetation damage reported at landscape (>1000km2) and regional (Nordic Arctic Region) scales in recent years. Critically, the damage caused by these extreme events is in direct opposition to 'Arctic greening', the well-established increase in productivity and shrub abundance observed at high latitudes in response to long-term warming. This opposition creates uncertainty as to future anticipated vegetation change in the Arctic, with implications for Arctic carbon balance. As high latitude ecosystems store around twice as much carbon as the atmosphere, and vegetation impacts are key to determining rates of loss or gain of ecosystem carbon stocks, Arctic browning has the potential to influence the role of these ecosystems in global climate. There is therefore a clear need for a quantitative understanding of the impacts of browning events on key ecosystem carbon fluxes. To address this, field sites were chosen in central and northern Norway and in Svalbard, in areas known to have been affected by either climatic extremes or insect outbreak and subsequent browning in the past four years. Sites were chosen along a latitudinal gradient to capture both conditions already causing vegetation browning throughout the Norwegian Arctic, and conditions currently common at lower latitudes which are likely to become more damaging further North as climate change progresses. At each site the response of Net Ecosystem CO2 Exchange to light was measured using a LiCor LI6400 Portable Photosynthesis system and a custom vegetation chamber with

  12. Quantifying snow and vegetation interactions in the high arctic based on ground penetrating radar (GPR)

    DEFF Research Database (Denmark)

    Gacitúa, G.; Bay, C.; Tamstorf, M.

    2013-01-01

    The quantification of the relationship between accumulation of snow and vegetation is crucial for understanding the influence of vegetation dynamics. We here present an analysis of the thickness of the snow and hydrological availability in relation to the seven main vegetation types in the High...... Arctic in Northeast Greenland. We used ground penetrating radar (GPR) for snow thickness measurements across the Zackenberg valley. Measurements were integrated to the physical conditions that support the vegetation distribution. Descriptive statistics and correlations of the distribution of each...

  13. Impacts of Snow Cover on Vegetation Phenology in the Arctic from Satellite Data

    Institute of Scientific and Technical Information of China (English)

    ZENG Heqing; JIA Gensuo

    2013-01-01

    The dynamics of snow cover is considered an essential factor in phenological changes in Arctic tundra and other northern biomes.The Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra satellite data were selected to monitor the spatial and temporal heterogeneity of vegetation phenology and the timing of snow cover in western Arctic Russia (the Yamal Peninsula) during the period 2000-10.The magnitude of changes in vegetation phenology and the timing of snow cover were highly heterogeneous across latitudinal gradients and vegetation types in western Arctic Russia.There were identical latitudinal gradients for "start of season" (SOS) (r2 =0.982,p<0.0001),"end of season" (EOS) (r2 =0.938,p<0.0001),and "last day of snow cover" (LSC) (r2 =0.984,p<0.0001),while slightly weaker relationships between latitudinal gradients and "first day of snow cover" (FSC) were observed (r2 =0.48,p<0.0042).Delayed SOS and FSC,and advanced EOS and LSC were found in the south of the region,while there were completely different shifts in the north.SOS for the various land cover features responded to snow cover differently,while EOS among different vegetation types responded to snowfall almost the same.The timing of snow cover is likely a key driving factor behind the dynamics of vegetation phenology over the Arctic tundra.The present study suggests that snow cover urgently needs more attention to advance understanding of vegetation phenology in the future.

  14. Vegetation

    DEFF Research Database (Denmark)

    Epstein, H.E.; Walker, D.A.; Bhatt, U.S.;

    2012-01-01

    • Over the past 30 years (1982-2011), the Normalized Difference Vegetation Index (NDVI), an index of green vegetation, has increased 15.5% in the North American Arctic and 8.2% in the Eurasian Arctic. In the more southern regions of Arctic tundra, the estimated aboveground plant biomass has...

  15. Energy fluxes retrieval on an Alaskan Arctic and Sub-Arctic vegetation by means MODIS imagery and the DTD method

    Science.gov (United States)

    Cristobal, J.; Prakash, A.; Starkenburg, D. P.; Fochesatto, G. J.; Anderson, M. C.; Gens, R.; Kane, D. L.; Kustas, W.; Alfieri, J. G.

    2012-12-01

    Evapotranspiration (ET) plays a significant role in the hydrologic cycle of Arctic and Sub-Arctic basins. Surface-atmosphere exchanges due to ET are estimated from water balance computations to be about 74% of summer precipitation or 50% of annual precipitation. Even though ET is a significant component of the hydrologic cycle in this region, the bulk estimates don't accurately account for spatial and temporal variability due to vegetation type, topography, etc. (Kane and Yang, 2004). Nowadays, remote sensing is the only technology capable of providing the necessary radiometric measurements for the calculation of the ET at global scales and in a feasible economic way, especially in Arctic and Sub-Arctic Alaskan basins with a very sparse network of both meteorological and flux towers. In this work we present the implementation and validation of the Dual-Time-Difference model (Kustas et al., 2001) to retrieve energy fluxes (ET, sensible heat flux, net radiation and soil heat flux) in tundra vegetation in Arctic conditions and in a black spruce (Picea mariana) forest in Sub-Arctic conditions. In order to validate the model in tundra vegetation we used a flux tower from the Imnavait Creek sites of the Arctic Observatory Network (Euskirchen et al. 2012). In the case of the black spruce forest, on September 2011 we installed a flux tower in the University of Alaska Fairbanks north campus that includes an eddy-covariance system as well a net radiometer, air temperature probes, soil heat flux plates, soil moisture sensors and thermistors to fully estimate energy fluxes in the field (see http://www.et.alaska.edu/ for further details). Additionally, in order to upscale energy fluxes into MODIS spatial resolution, a scintillometer was also installed covering 1.2 km across the flux tower. DTD model mainly requires meteorological inputs as well as land surface temperature (LST) and leaf area index (LAI) data, both coming from satellite imagery, at two different times: after

  16. Spatial variation in vegetation productivity trends, fire disturbance, and soil carbon across arctic-boreal permafrost ecosystems

    Science.gov (United States)

    Loranty, Michael M.; Liberman-Cribbin, Wil; Berner, Logan T.; Natali, Susan M.; Goetz, Scott J.; Alexander, Heather D.; Kholodov, Alexander L.

    2016-09-01

    In arctic tundra and boreal forest ecosystems vegetation structural and functional influences on the surface energy balance can strongly influence permafrost soil temperatures. As such, vegetation changes will likely play an important role in permafrost soil carbon dynamics and associated climate feedbacks. Processes that lead to changes in vegetation, such as wildfire or ecosystem responses to rising temperatures, are of critical importance to understanding the impacts of arctic and boreal ecosystems on future climate. Yet these processes vary within and between ecosystems and this variability has not been systematically characterized across the arctic-boreal region. Here we quantify the distribution of vegetation productivity trends, wildfire, and near-surface soil carbon, by vegetation type, across the zones of continuous and discontinuous permafrost. Siberian larch forests contain more than one quarter of permafrost soil carbon in areas of continuous permafrost. We observe pervasive positive trends in vegetation productivity in areas of continuous permafrost, whereas areas underlain by discontinuous permafrost have proportionally less positive productivity trends and an increase in areas exhibiting negative productivity trends. Fire affects a much smaller proportion of the total area and thus a smaller amount of permafrost soil carbon, with the vast majority occurring in deciduous needleleaf forests. Our results indicate that vegetation productivity trends may be linked to permafrost distribution, fire affects a relatively small proportion of permafrost soil carbon, and Siberian larch forests will play a crucial role in the strength of the permafrost carbon climate feedback.

  17. Modelling high arctic percent vegetation cover using field digital images and high resolution satellite data

    Science.gov (United States)

    Liu, Nanfeng; Treitz, Paul

    2016-10-01

    In this study, digital images collected at a study site in the Canadian High Arctic were processed and classified to examine the spatial-temporal patterns of percent vegetation cover (PVC). To obtain the PVC of different plant functional groups (i.e., forbs, graminoids/sedges and mosses), field near infrared-green-blue (NGB) digital images were classified using an object-based image analysis (OBIA) approach. The PVC analyses comparing different vegetation types confirmed: (i) the polar semi-desert exhibited the lowest PVC with a large proportion of bare soil/rock cover; (ii) the mesic tundra cover consisted of approximately 60% mosses; and (iii) the wet sedge consisted almost exclusively of graminoids and sedges. As expected, the PVC and green normalized difference vegetation index (GNDVI; (RNIR - RGreen)/(RNIR + RGreen)), derived from field NGB digital images, increased during the summer growing season for each vegetation type: i.e., ∼5% (0.01) for polar semi-desert; ∼10% (0.04) for mesic tundra; and ∼12% (0.03) for wet sedge respectively. PVC derived from field images was found to be strongly correlated with WorldView-2 derived normalized difference spectral indices (NDSI; (Rx - Ry)/(Rx + Ry)), where Rx is the reflectance of the red edge (724.1 nm) or near infrared (832.9 nm and 949.3 nm) bands; Ry is the reflectance of the yellow (607.7 nm) or red (658.8 nm) bands with R2's ranging from 0.74 to 0.81. NDSIs that incorporated the yellow band (607.7 nm) performed slightly better than the NDSIs without, indicating that this band may be more useful for investigating Arctic vegetation that often includes large proportions of senescent vegetation throughout the growing season.

  18. Transitions in high-Arctic vegetation growth patterns and ecosystem productivity from 2000-2013 tracked with cameras

    DEFF Research Database (Denmark)

    Westergaard-Nielsen, Andreas; Lund, Magnus; Pedersen, Stine Højlund;

    2016-01-01

    The changes in vegetation seasonality at northern latitudes, resulting from changes in atmospheric temperatures and precipitation, are still not well understood. In this study we used 13 years of time lapse camera data and climate data from high-Arctic Northeast Greenland to assess the seasonal...... response of three vegetation types (dwarf shrub heath, grassland, and fen) to changes in snow cover, soil moisture, and air and soil temperatures. Based on the camera data, we computed a greenness index, which was subsequently used to analyze transition dates in vegetation seasonality. Snow cover...

  19. Potential Arctic tundra vegetation shifts in response to changing temperature, precipitation and permafrost thaw

    Science.gov (United States)

    van der Kolk, Henk-Jan; Heijmans, Monique M. P. D.; van Huissteden, Jacobus; Pullens, Jeroen W. M.; Berendse, Frank

    2016-11-01

    Over the past decades, vegetation and climate have changed significantly in the Arctic. Deciduous shrub cover is often assumed to expand in tundra landscapes, but more frequent abrupt permafrost thaw resulting in formation of thaw ponds could lead to vegetation shifts towards graminoid-dominated wetland. Which factors drive vegetation changes in the tundra ecosystem are still not sufficiently clear. In this study, the dynamic tundra vegetation model, NUCOM-tundra (NUtrient and COMpetition), was used to evaluate the consequences of climate change scenarios of warming and increasing precipitation for future tundra vegetation change. The model includes three plant functional types (moss, graminoids and shrubs), carbon and nitrogen cycling, water and permafrost dynamics and a simple thaw pond module. Climate scenario simulations were performed for 16 combinations of temperature and precipitation increases in five vegetation types representing a gradient from dry shrub-dominated to moist mixed and wet graminoid-dominated sites. Vegetation composition dynamics in currently mixed vegetation sites were dependent on both temperature and precipitation changes, with warming favouring shrub dominance and increased precipitation favouring graminoid abundance. Climate change simulations based on greenhouse gas emission scenarios in which temperature and precipitation increases were combined showed increases in biomass of both graminoids and shrubs, with graminoids increasing in abundance. The simulations suggest that shrub growth can be limited by very wet soil conditions and low nutrient supply, whereas graminoids have the advantage of being able to grow in a wide range of soil moisture conditions and have access to nutrients in deeper soil layers. Abrupt permafrost thaw initiating thaw pond formation led to complete domination of graminoids. However, due to increased drainage, shrubs could profit from such changes in adjacent areas. Both climate and thaw pond formation

  20. Phenological dynamics of arctic tundra vegetation and its implications on satellite imagery interpretation

    Science.gov (United States)

    Juutinen, Sari; Aurela, Mika; Mikola, Juha; Räsänen, Aleksi; Virtanen, Tarmo

    2016-04-01

    Remote sensing is a key methodology when monitoring the responses of arctic ecosystems to climatic warming. The short growing season and rapid vegetation development, however, set demands to the timing of image acquisition in the arctic. We used multispectral very high spatial resolution satellite images to study the effect of vegetation phenology on the spectral reflectance and image interpretation in the low arctic tundra in coastal Siberia (Tiksi, 71°35'39"N, 128°53'17"E). The study site mainly consists of peatlands, tussock, dwarf shrub, and grass tundra, and stony areas with some lichen and shrub patches. We tested the hypotheses that (1) plant phenology is responsive to the interannual weather variation and (2) the phenological state of vegetation has an impact on satellite image interpretation and the ability to distinguish between the plant communities. We used an empirical transfer function with temperature sums as drivers to reconstruct daily leaf area index (LAI) for the different plant communities for years 2005, and 2010-2014 based on measured LAI development in summer 2014. Satellite images, taken during growing seasons, were acquired for two years having late and early spring, and short and long growing season, respectively. LAI dynamics showed considerable interannual variation due to weather variation, and particularly the relative contribution of graminoid dominated communities was sensitive to these phenology shifts. We have also analyzed the differences in the reflectance values between the two satellite images taking account the LAI dynamics. These results will increase our understanding of the pitfalls that may arise from the timing of image acquisition when interpreting the vegetation structure in a heterogeneous tundra landscape. Very high spatial resolution multispectral images are available at reasonable cost, but not in high temporal resolution, which may lead to compromises when matching ground truth and the imagery. On the other hand

  1. Recovery and archiving key Arctic Alaska vegetation map and plot data for the Arctic-Boreal Vulnerability Field Experiment (ABoVE)

    Science.gov (United States)

    Walker, D. A.; Breen, A. L.; Broderson, D.; Epstein, H. E.; Fisher, W.; Grunblatt, J.; Heinrichs, T.; Raynolds, M. K.; Walker, M. D.; Wirth, L.

    2013-12-01

    Abundant ground-based information will be needed to inform remote-sensing and modeling studies of NASA's Arctic-Boreal Vulnerability Experiment (ABoVE). A large body of plot and map data collected by the Alaska Geobotany Center (AGC) and collaborators from the Arctic regions of Alaska and the circumpolar Arctic over the past several decades is being archived and made accessible to scientists and the public via the Geographic Information Network of Alaska's (GINA's) 'Catalog' display and portal system. We are building two main types of data archives: Vegetation Plot Archive: For the plot information we use a Turboveg database to construct the Alaska portion of the international Arctic Vegetation Archive (AVA) http://www.geobotany.uaf.edu/ava/. High quality plot data and non-digital legacy datasets in danger of being lost have highest priority for entry into the archive. A key aspect of the database is the PanArctic Species List (PASL-1), developed specifically for the AVA to provide a standard of species nomenclature for the entire Arctic biome. A wide variety of reports, documents, and ancillary data are linked to each plot's geographic location. Geoecological Map Archive: This database includes maps and remote sensing products and links to other relevant data associated with the maps, mainly those produced by the Alaska Geobotany Center. Map data include GIS shape files of vegetation, land-cover, soils, landforms and other categorical variables and digital raster data of elevation, multispectral satellite-derived data, and data products and metadata associated with these. The map archive will contain all the information that is currently in the hierarchical Toolik-Arctic Geobotanical Atlas (T-AGA) in Alaska http://www.arcticatlas.org, plus several additions that are in the process of development and will be combined with GINA's already substantial holdings of spatial data from northern Alaska. The Geoecological Atlas Portal uses GINA's Catalog tool to develop a

  2. Divergent Arctic-Boreal Vegetation Changes between North America and Eurasia over the Past 30 Years

    Directory of Open Access Journals (Sweden)

    Arindam Samanta

    2013-05-01

    Full Text Available Arctic-Boreal region—mainly consisting of tundra, shrub lands, and boreal forests—has been experiencing an amplified warming over the past 30 years. As the main driving force of vegetation growth in the north, temperature exhibits tight coupling with the Normalized Difference Vegetation Index (NDVI—a proxy to photosynthetic activity. However, the comparison between North America (NA and northern Eurasia (EA shows a weakened spatial dependency of vegetation growth on temperature changes in NA during the past decade. If this relationship holds over time, it suggests a 2/3 decrease in vegetation growth under the same rate of warming in NA, while the vegetation response in EA stays the same. This divergence accompanies a circumpolar widespread greening trend, but 20 times more browning in the Boreal NA compared to EA, and comparative greening and browning trends in the Arctic. These observed spatial patterns of NDVI are consistent with the temperature record, except in the Arctic NA, where vegetation exhibits a similar long-term trend of greening to EA under less warming. This unusual growth pattern in Arctic NA could be due to a lack of precipitation velocity compared to the temperature velocity, when taking velocity as a measure of northward migration of climatic conditions.

  3. Relationships between hyperspectral data and components of vegetation biomass in Low Arctic tundra communities at Ivotuk, Alaska

    Science.gov (United States)

    Bratsch, Sara; Epstein, Howard; Buchhorn, Marcel; Walker, Donald; Landes, Heather

    2017-02-01

    Warming in the Arctic has resulted in a lengthening of the growing season and changes to the distribution and composition of tundra vegetation including increased biomass quantities in the Low Arctic. Biomass has commonly been estimated using broad-band greenness indices such as NDVI; however, vegetation changes in the Arctic are occurring at spatial scales within a few meters. The aim of this paper is to assess the ability of hyperspectral remote sensing data to estimate biomass quantities among different plant tissue type categories at the North Slope site of Ivotuk, Alaska. Hand-held hyperspectral data and harvested biomass measurements were collected during the 1999 growing season. A subset of the data was used as a training set, and was regressed against the hyperspectral bands using LASSO. LASSO is a modification of SPLS and is a variable selection technique that is useful in studies with high collinearity among predictor variables such as hyperspectral remote sensing. The resulting equations were then used to predict biomass quantities for the remaining Ivotuk data. The majority of significant biomass-spectra relationships (65%) were for shrubs categories during all times of the growing season and bands in the blue, green, and red edge wavelength regions of the spectrum. The ability to identify unique biomass-spectra relationships per community is decreased at the height of the growing season when shrubs obscure lower-lying vegetation such as mosses. The results of this study support previous research arguing that shrubs are dominant controls over spectral reflectance in Low Arctic communities and that this dominance results in an increased ability to estimate shrub component biomass over other plant functional types.

  4. LANDFIRE (90m) Existing Vegetation Type

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map depicts the distribution of existing vegetation types contained in the LANDFIRE dataset. All 30-meter EVT grids were resampled to 90-meter grids and merged...

  5. Vegetation shifts observed in arctic tundra 17 years after fire

    Science.gov (United States)

    Barrett, Kirsten; Rocha, Adrian V.; van de Weg, Martine Janet; Shaver, Gaius

    2012-01-01

    With anticipated climate change, tundra fires are expected to occur more frequently in the future, but data on the long-term effects of fire on tundra vegetation composition are scarce. This study addresses changes in vegetation structure that have persisted for 17 years after a tundra fire on the North Slope of Alaska. Fire-related shifts in vegetation composition were assessed from remote-sensing imagery and ground observations of the burn scar and an adjacent control site. Early-season remotely sensed imagery from the burn scar exhibits a low vegetation index compared with the control site, whereas the late-season signal is slightly higher. The range and maximum vegetation index are greater in the burn scar, although the mean annual values do not differ among the sites. Ground observations revealed a greater abundance of moss in the unburned site, which may account for the high early growing season normalized difference vegetation index (NDVI) anomaly relative to the burn. The abundance of graminoid species and an absence of Betula nana in the post-fire tundra sites may also be responsible for the spectral differences observed in the remotely sensed imagery. The partial replacement of tundra by graminoid-dominated ecosystems has been predicted by the ALFRESCO model of disturbance, climate and vegetation succession.

  6. Mapping Arctic Tundra Vegetation Communities Using Field Spectroscopy and Multispectral Satellite Data in North Alaska, USA

    Directory of Open Access Journals (Sweden)

    Scott J. Davidson

    2016-11-01

    Full Text Available The Arctic is currently undergoing intense changes in climate; vegetation composition and productivity are expected to respond to such changes. To understand the impacts of climate change on the function of Arctic tundra ecosystems within the global carbon cycle, it is crucial to improve the understanding of vegetation distribution and heterogeneity at multiple scales. Information detailing the fine-scale spatial distribution of tundra communities provided by high resolution vegetation mapping, is needed to understand the relative contributions of and relationships between single vegetation community measurements of greenhouse gas fluxes (e.g., ~1 m chamber flux and those encompassing multiple vegetation communities (e.g., ~300 m eddy covariance measurements. The objectives of this study were: (1 to determine whether dominant Arctic tundra vegetation communities found in different locations are spectrally distinct and distinguishable using field spectroscopy methods; and (2 to test which combination of raw reflectance and vegetation indices retrieved from field and satellite data resulted in accurate vegetation maps and whether these were transferable across locations to develop a systematic method to map dominant vegetation communities within larger eddy covariance tower footprints distributed along a 300 km transect in northern Alaska. We showed vegetation community separability primarily in the 450–510 nm, 630–690 nm and 705–745 nm regions of the spectrum with the field spectroscopy data. This is line with the different traits of these arctic tundra communities, with the drier, often non-vascular plant dominated communities having much higher reflectance in the 450–510 nm and 630–690 nm regions due to the lack of photosynthetic material, whereas the low reflectance values of the vascular plant dominated communities highlight the strong light absorption found here. High classification accuracies of 92% to 96% were achieved using

  7. Circumpolar Arctic vegetation: a hierarchic review and roadmap toward an internationally consistent approach to survey, archive and classify tundra plot data

    Science.gov (United States)

    Walker, D. A.; Daniëls, F. J. A.; Alsos, I.; Bhatt, U. S.; Breen, A. L.; Buchhorn, M.; Bültmann, H.; Druckenmiller, L. A.; Edwards, M. E.; Ehrich, D.; Epstein, H. E.; Gould, W. A.; Ims, R. A.; Meltofte, H.; Raynolds, M. K.; Sibik, J.; Talbot, S. S.; Webber, P. J.

    2016-05-01

    Satellite-derived remote-sensing products are providing a modern circumpolar perspective of Arctic vegetation and its changes, but this new view is dependent on a long heritage of ground-based observations in the Arctic. Several products of the Conservation of Arctic Flora and Fauna are key to our current understanding. We review aspects of the PanArctic Flora, the Circumpolar Arctic Vegetation Map, the Arctic Biodiversity Assessment, and the Arctic Vegetation Archive (AVA) as they relate to efforts to describe and map the vegetation, plant biomass, and biodiversity of the Arctic at circumpolar, regional, landscape and plot scales. Cornerstones for all these tools are ground-based plant-species and plant-community surveys. The AVA is in progress and will store plot-based vegetation observations in a public-accessible database for vegetation classification, modeling, diversity studies, and other applications. We present the current status of the Alaska Arctic Vegetation Archive (AVA-AK), as a regional example for the panarctic archive, and with a roadmap for a coordinated international approach to survey, archive and classify Arctic vegetation. We note the need for more consistent standards of plot-based observations, and make several recommendations to improve the linkage between plot-based observations biodiversity studies and satellite-based observations of Arctic vegetation.

  8. Arctic shrubification mediates the impacts of warming climate on changes to tundra vegetation

    Science.gov (United States)

    Mod, Heidi K.; Luoto, Miska

    2016-12-01

    Climate change has been observed to expand distributions of woody plants in many areas of arctic and alpine environments—a phenomenon called shrubification. New spatial arrangements of shrubs cause further changes in vegetation via changing dynamics of biotic interactions. However, the mediating influence of shrubification is rarely acknowledged in predictions of tundra vegetation change. Here, we examine possible warming-induced landscape-level vegetation changes in a high-latitude environment using species distribution modelling (SDM), specifically concentrating on the impacts of shrubification on ambient vegetation. First, we produced estimates of current shrub and tree cover and forecasts of their expansion under climate change scenarios to be incorporated to SDMs of 116 vascular plants. Second, the predictions of vegetation change based on the models including only abiotic predictors and the models including abiotic, shrub and tree predictors were compared in a representative test area. Based on our model predictions, abundance of woody plants will expand, thus decreasing predicted species richness, amplifying species turnover and increasing the local extinction risk for ambient vegetation. However, the spatial variation demonstrated in our predictions highlights that tundra vegetation can be expected to show a wide variety of different responses to the combined effects of warming and shrubification, depending on the original plant species pool and environmental conditions. We conclude that realistic forecasts of the future require acknowledging the role of shrubification in warming-induced tundra vegetation change.

  9. Recent Declines in Warming and Vegetation Greening Trends over Pan-Arctic Tundra

    Directory of Open Access Journals (Sweden)

    Igor V. Polyakov

    2013-08-01

    Full Text Available Vegetation productivity trends for the Arctic tundra are updated for the 1982–2011 period and examined in the context of land surface temperatures and coastal sea ice. Understanding mechanistic links between vegetation and climate parameters contributes to model advancements that are necessary for improving climate projections. This study employs remote sensing data: Global Inventory Modeling and Mapping Studies (GIMMS Maximum Normalized Difference Vegetation Index (MaxNDVI, Special Sensor Microwave Imager (SSM/I sea-ice concentrations, and Advanced Very High Resolution Radiometer (AVHRR radiometric surface temperatures. Spring sea ice is declining everywhere except in the Bering Sea, while summer open water area is increasing throughout the Arctic. Summer Warmth Index (SWI—sum of degree months above freezing trends from 1982 to 2011 are positive around Beringia but are negative over Eurasia from the Barents to the Laptev Seas and in parts of northern Canada. Eastern North America continues to show increased summer warmth and a corresponding steady increase in MaxNDVI. Positive MaxNDVI trends from 1982 to 2011 are generally weaker compared to trends from 1982–2008. So to better understand the changing trends, break points in the time series were quantified using the Breakfit algorithm. The most notable break points identify declines in SWI since 2003 in Eurasia and 1998 in Western North America. The Time Integrated NDVI (TI-NDVI, sum of the biweekly growing season values of MaxNDVI has declined since 2005 in Eurasia, consistent with SWI declines. Summer (June–August sea level pressure (slp averages from 1999–2011 were compared to those from 1982–1998 to reveal higher slp over Greenland and the western Arctic and generally lower pressure over the continental Arctic in the recent period. This suggests that the large-scale circulation is likely a key contributor to the cooler temperatures over Eurasia through increased summer cloud

  10. Arctic Vegetation under Climate Change – Biogenic Volatile Organic Compound Emissions and Leaf Anatomy

    DEFF Research Database (Denmark)

    Schollert, Michelle

    Biogenic volatile organic compounds (BVOCs) emitted from terrestrial vegetation are highly reactive non-methane hydrocarbons which participate in oxidative reactions in the atmosphere prolonging the lifetime of methane and contribute to the formation of secondary organic aerosols. The BVOC...... measurements in this thesis were performed using a dynamic enclosure system and collection of BVOCs into adsorbent cartridges analyzed by gas chromatography-mass spectrometry following thermal desorption. Also modifications in leaf anatomy in response to the studied effects of climate change were assessed...... by the use of light microscopy and scanning electron microscopy. This thesis reports the first estimates of high arctic BVOC emissions, which suggest that arctic environments can be a considerable source of BVOCs to the atmosphere. The BVOC emissions differed qualitatively and quantitatively for the studied...

  11. Feedbacks Between Microenvironment and Plant Functional Type and Implications for CO2 Flux in Arctic Ecosystems

    Science.gov (United States)

    Squires, E.; Rodenheizer, H.; Natali, S.; Mann, P.

    2013-12-01

    Future climate models predict a warmer, drier Arctic, with resultant shifts in vegetative composition and implications for ecosystem carbon budgets. The impact of vegetation change, however, may depend on which plant functional groups are favored in a warming Arctic. Physiological and functional differences between plant groups influence both the local microenvironment and, on a broader scale, whole-ecosystem CO2 flux. We examined the interactions between plants and their microenvironment, and analyzed the effect of these interactions on both soil microbial communities and CO2 flux across different functional groups. Physical and biological aspects of the microenvironment differed between plant functional groups. Lichen patches were characterized by deeper thaw depths, lower soil moisture, greater thermal conductivity, and a thinner organic layer than mosses. To better understand the development of these plant-environment interactions, we conducted a reciprocal transplant experiment, switching multiple lichen and moss patches. Temporal changes in environmental parameters at these sites will demonstrate how different plants modify their environment and will help identify associated implications for soil microbial communities and CO2 flux. We measured CO2 flux and used Biolog assays to examine soil microbial communities in undisturbed patches of mosses, lichens, and shrubs. Patches of birch shrubs had more negative net ecosystem exchange, signifying a carbon sink. Soils from alder shrubs and mosses hosted more active microbial communities than soils under birch shrubs and lichens. These results suggest a strong link between environment, plant functional type, and C cycling. Understanding how this relationship differs among plant functional types is an important part of predicting ecosystem carbon budgets as Arctic vegetation composition shifts in response to climate change.

  12. Changes in Arctic vegetation amplify high-latitude warming through the greenhouse effect.

    Science.gov (United States)

    Swann, Abigail L; Fung, Inez Y; Levis, Samuel; Bonan, Gordon B; Doney, Scott C

    2010-01-26

    Arctic climate is projected to change dramatically in the next 100 years and increases in temperature will likely lead to changes in the distribution and makeup of the Arctic biosphere. A largely deciduous ecosystem has been suggested as a possible landscape for future Arctic vegetation and is seen in paleo-records of warm times in the past. Here we use a global climate model with an interactive terrestrial biosphere to investigate the effects of adding deciduous trees on bare ground at high northern latitudes. We find that the top-of-atmosphere radiative imbalance from enhanced transpiration (associated with the expanded forest cover) is up to 1.5 times larger than the forcing due to albedo change from the forest. Furthermore, the greenhouse warming by additional water vapor melts sea-ice and triggers a positive feedback through changes in ocean albedo and evaporation. Land surface albedo change is considered to be the dominant mechanism by which trees directly modify climate at high-latitudes, but our findings suggest an additional mechanism through transpiration of water vapor and feedbacks from the ocean and sea-ice.

  13. A Survey of Submerged Aquatic Vegetation in Three Sub-arctic Lakes near Abisko, Sweden

    Science.gov (United States)

    Sampson, J.; Stilson, K.; Varner, R. K.; Crill, P. M.; Wik, M.; Crawford, M.

    2014-12-01

    We surveyed the submerged aquatic vegetation (SAV) in three sub-arctic lakes (Mellan Harrsjön, Inre Harrsjön, and Villasjön) located near Abisko in northern Sweden. Samples were collected using an extended rake, after which they were photographed and the plants identified. We also collected environmental data including temperature, dissolved oxygen, and secchi depth. Percent cover of SAV was taken twice using a 0.5 m. quadrat in shallow areas to track the changes in vegetation growth over time. In addition, we tested surface sediment samples for grain size and carbon, hydrogen, nitrogen, and sulfur composition. The percent cover of SAV in Mellan Harrsjön varied from 36%-49% and in Inre Harrsjön it averaged 19%. Across all three lakes, the average percent clay, silt, and sand was 3.8%, 50.1%, 46%, respectively. Because little research similar to this has been conducted in the area in such a comprehensive manner, these results are important to establish a baseline. Furthermore, these data will help establish how the SAV and environmental data may contribute to methane production and emission in these sub-arctic lakes.

  14. Relationship of cyanobacterial and algal assemblages with vegetation in the high Arctic tundra (West Spitsbergen, Svalbard Archipelago

    Directory of Open Access Journals (Sweden)

    Richter Dorota

    2015-09-01

    Full Text Available The paper presents the results of a study of cyanobacteria and green algae assemblages occurring in various tundra types determined on the basis of mosses and vascular plants and habitat conditions. The research was carried out during summer in the years 2009-2013 on the north sea-coast of Hornsund fjord (West Spitsbergen, Svalbard Archipelago. 58 sites were studied in various tundra types differing in composition of vascular plants, mosses and in trophy and humidity. 141 cyanobacteria and green algae were noted in the research area in total. Cyanobacteria and green algae flora is a significant element of many tundra types and sometimes even dominate there. Despite its importance, it has not been hitherto taken into account in the description and classification of tundra. The aim of the present study was to demonstrate the legitimacy of using phycoflora in supplementing the descriptions of hitherto described tundra and distinguishing new tundra types. Numeric hierarchical-accumulative classification (MVSP 3.1 software methods were used to analyze the cyanobacterial and algal assemblages and their co-relations with particular tundra types. The analysis determined dominant and distinctive species in the communities in concordance with ecologically diverse types of tundra. The results show the importance of these organisms in the composition of the vegetation of tundra types and their role in the ecosystems of this part of the Arctic.

  15. Remote sensing of vegetation and land-cover change in Arctic Tundra Ecosystems

    Science.gov (United States)

    Stow, D.A.; Hope, A.; McGuire, D.; Verbyla, D.; Gamon, J.; Huemmrich, F.; Houston, S.; Racine, C.; Sturm, M.; Tape, K.; Hinzman, L.; Yoshikawa, K.; Tweedie, C.; Noyle, B.; Silapaswan, C.; Douglas, D.; Griffith, B.; Jia, G.; Epstein, H.; Walker, D.; Daeschner, S.; Petersen, A.; Zhou, L.; Myneni, R.

    2004-01-01

    The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land-Air-Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonstrate that ground-level sensors on stationary or moving track platforms and wide-swath imaging sensors on polar orbiting satellites are particularly useful for capturing optical remote sensing data at sufficient frequency to study tundra vegetation dynamics and changes for the cloud prone Arctic. Less frequent imaging with high spatial resolution instruments on aircraft and lower orbiting satellites enable more detailed analyses of land cover change and calibration/validation of coarser resolution observations. The strongest signals of ecosystem change detected thus far appear to correspond to expansion of tundra shrubs and changes in the amount and extent of thaw lakes and ponds. Changes in shrub cover and extent have been documented by modern repeat imaging that matches archived historical aerial photography. NOAA Advanced Very High Resolution Radiometer (AVHRR) time series provide a 20-year record for determining changes in greenness that relates to photosynthetic activity, net primary production, and growing season length. The strong contrast between land materials and surface waters enables changes in lake and pond extent to be readily measured and monitored. ?? 2003 Elsevier Inc. All rights reserved.

  16. Vegetation type classification and vegetation cover percentage estimation in urban green zone using pleiades imagery

    Science.gov (United States)

    Trisakti, Bambang

    2017-01-01

    Open green space in the urban area has aims to maintain the availability of land as a water catchment area, creating aspects of urban planning through a balance between the natural environment and the built environment that are useful for the public needs. Local governments have to make the green zone plan map and monitor the green space changes in their territory. Medium and high resolution satellite imageries have been widely utilized to map and monitor the changes of vegetation cover as an indicator of green space area. This paper describes the use of pleaides imagery to classify vegetation types and estimate vegetation cover percentage in the green zone. Vegetation cover was mapped using a combination of NDVI and blue band. Furthermore, vegetation types in the green space were classified using unsupervised and supervised (ISODATA and MLEN) methods. Vegetation types in the study area were divided into sparse vegetation, low-medium vegetation and medium-high vegetation. The classification accuracies were 97.9% and 98.9% for unsupervised and supervised method respectively. The vegetation cover percentage was determined by calculating the ratio between the vegetation type area and the green zone area. These information are useful to support green zone management activities.

  17. Impact of interactive vegetation phenology on the simulated pan-Arctic land surface state

    Science.gov (United States)

    Teufel, Bernardo; Sushama, Laxmi

    2016-04-01

    The pan-Arctic land surface is undergoing rapid changes in a warming climate, with near-surface permafrost projected to degrade significantly during the 21st century. This can have important impacts on the regional climate and hydrology through various feedbacks, including vegetation-related feedbacks. In this study, the impact of interactive phenology on the land surface state, including near-surface permafrost, is assessed by comparing two simulations of the Canadian Land Surface Scheme (CLASS) - one with interactive phenology, modelled using the Canadian Terrestrial Ecosystem Model (CTEM), and the other with prescribed phenology. These simulations are performed for the 1979-2012 period, using atmospheric forcing from ECMWF's ERA-Interim reanalysis. The impact of interactive phenology on projected changes to the land surface state are also assessed by comparing two simulations of CLASS (with and without interactive phenology), spanning the 1961-2100 period, driven by atmospheric forcing from a transient climate change simulation of the 5th generation Canadian Regional Climate Model (CRCM5) for the Representative Concentration Pathway 8.5 (RCP8.5). Comparison of the CLASS coupled to CTEM simulation with available observational estimates of plant area index, primary productivity, spatial distribution of permafrost and active layer thickness suggests that the model captures reasonably well the general distribution of vegetation and permafrost. Significant differences in evapotranspiration, leading to differences in runoff, soil temperature and active layer thickness are noted when comparing CLASS simulations with and without interactive phenology. Furthermore, the CLASS simulations with and without interactive phenology for RCP8.5 show extensive near-surface permafrost degradation by the end of the 21st century, with slightly accelerated degradation of permafrost in the simulation with interactive phenology, pointing towards a positive feedback of changes in

  18. Two Types of Arctic Oscillation and Their Associated Dynamic Features

    Institute of Scientific and Technical Information of China (English)

    SHI Ning; BUEH Cholaw

    2011-01-01

    In this paper, the dynamical evolutions of two types of Arctic Oscillation (AO), the stratospheric (S) and tropospheric (T) types, have been investigated on an intermediate time scale in terms of transient eddy feedback forcing and three-dimensional Rossby wave propagation. S-Type (T-type) events are characterized by an anomalous stratospheric polar vortex that is in phase (out of phase) with its tropospheric counterpart. Approximately onethird of AO events, both positive and negative, are T-type events. For the positive phase of a T-type event, the formation and maintenance of stratospheric positive anomalies over the polar cap are associated with an upward propagation of Rossby wave packets originating from the near-tropopause altitude over northeastern Asia. However, such upward propagating features are not found for S-type events. In the troposphere, transient eddy feedback forcing is primarily responsible for the meridional seesaw structure of both the S- and T-type events, with an addi- tional contribution from Rossby wave propagation.

  19. Three-Dimensional Dynamic Features of Two Arctic Oscillation Types

    Institute of Scientific and Technical Information of China (English)

    SHI Ning; BUEH Cholaw

    2013-01-01

    We investigated the differences between stratospheric (S-type) and tropospheric (T-type) Arctic Oscillation (AO) events on the intraseasonal time scale,in terms of their influences on surface air temperature (SAT) over the Northern Hemisphere and the dynamic features associated with their spatial structures.S-type AO events showed a stratosphere-troposphere coupled structure,while T-type events exhibited a stratosphere-troposphere uncoupled structure.The annular SAT anomalies over the Northern Hemisphere were found to be associated with S-type AO events,whereas such an annular feature was substantially destructed in T-type AO events.The different horizontal structures in the troposphere of the two types could mainly be attributed to transient eddy feedback forcing.As for the vertically uncoupled structure of Ttype events,the underlying dynamical features that differentiate them from S-type events lie in the vertical propagation of zonally confined Rossby waves.In T-type events,the zonally confined Rossby wave packets can emanate from the significant height anomalies over Northeast Asia,where one vertical waveguide exists,and then propagate upward into the stratosphere.In contrast,such a vertical propagation was not evident for S-type events.The stratospheric anomalies associated with the upward injection of the zonally confined Rossby waves from the troposphere in T-type events can further induce the anomalous vertical propagation of planetary waves (PWs) through the interference between the climatological-mean PWs and anomalous PWs,leading to the final stratosphere-troposphere uncoupled structure of T-type events.

  20. The regional species richness and genetic diversity of Arctic vegetation reflect both past glaciations and current climate

    DEFF Research Database (Denmark)

    Stewart, L.; Alsos, Inger G.; Bay, Christian

    2016-01-01

    correlated with each other, and both showed a positive relationship with landscape age. Plot species richness showed differing responses for vascular plants, bryophytes and lichens. At this finer scale, the richness of vascular plants was not significantly related to landscape age, which had a small effect...... size compared to the models of bryophyte and lichen richness. Main conclusion Our study suggests that imprints of past glaciations in Arctic vegetation diversity patterns at the regional scale are still detectable today. Since Arctic vegetation is still limited by post-glacial migration lag......, it will most probably also exhibit lags in response to current and future climate change. Our results also suggest that local species richness at the plot scale is more determined by local habitat factors...

  1. Camera derived vegetation greenness index as proxy for gross primary production in a low Arctic wetland area

    DEFF Research Database (Denmark)

    Westergaard-Nielsen, Andreas; Lund, Magnus; Hansen, Birger Ulf;

    2013-01-01

    vegetation index (NDVI) product derived from the WorldView-2 satellite. An object-based classification based on a bi-temporal image composite was used to classify the study area into heath, copse, fen, and bedrock. Temporal evolution of vegetation greenness was evaluated and modeled with double sigmoid...... of these changes. This study investigates the ability to use automatic digital camera images (DCIs) as proxy data for gross primary production (GPP) in a complex low Arctic wetland site. Vegetation greenness computed from DCIs was found to correlate significantly (R-2 = 0.62, p ... functions for each plant community. GPP at light saturation modeled from eddy covariance (EC) flux measurements were found to correlate significantly with vegetation greenness for all plant communities in the studied year (i.e., 2010), and the highest correlation was found between modeled fen greenness...

  2. Characterization of Vegetation Change in a Sub-Arctic Mire using Remotely Sensed Imagery

    Science.gov (United States)

    DelGreco, J. L.; McArthur, K. J.; Palace, M. W.; Herrick, C.; Garnello, A.; Finnell, D.; McCalley, C. K.; Anderson, S. M.; Varner, R. K.

    2015-12-01

    Climate change is impacting northern ecosystems through the thawing of the permafrost, which has resulted in changes to plant communities and greenhouse gas emissions, such as carbon dioxide (CO2) and methane (CH4). These greenhouse gases are of concern due to their potential feedbacks which create a warmer climate, thus increasing permafrost thawing. Our study focuses on how vegetation type differs in areas that have been impacted by thawing permafrost at Stordalen Mire located in Abisko, Sweden. To estimate change in vegetation communities, field-based measurements combined with remotely sensed image data was used. 75 randomized square-meter plots were measured for vegetation composition and classified into one of five site-types, each representing a different stage of permafrost degradation. New high-resolution imagery (1 cm) was collected using Unmanned Aerial Vehicles (UAV) providing insight into the spatial patterning, characterizations, and changes of these communities. The UAV imagery was georectified using high precision GPS points collected across the mire. The imagery was then examined using a neural network analysis to estimate cover type across the mire. This 2015 cover type classification was then compared to previous UAV imagery taken on July 2014 to analyze changes in vegetation distribution as an indication of permafrost thaw. Hummock sites represent intact permafrost and have lost 21.5% coverage since 2014, while tall gramminoid sites, which indicate fully thawed sites, have increased coverage by 12.1%. A discriminate function analysis showed that site types can be differentiated based on species composition, thus showing that vegetation differs significantly across the thaw gradient. Using average flux rates of CH4 from each cover type reported previously, the percent of CH4 emitted over the mire was estimated for 2014 and 2015. Comparing both estimates, CH4 emissions increased with a flux change of 5604.5 g CH4/day. Our estimates of vegetation

  3. Accumulation of carbon and nitrogen in vegetation and soils of deglaciated area in Ellesmere Island, high-Arctic Canada

    Science.gov (United States)

    Osono, Takashi; Mori, Akira S.; Uchida, Masaki; Kanda, Hiroshi

    2016-09-01

    The amount of biomass, carbon (C), and nitrogen (N) in vegetation and soil were measured at two spatial scales in the high Arctic. At the scale of proglacial landscape, the amount of C and N in aboveground and belowground parts of vegetation, surface litter, and soil were significantly affected by the habitat (moraines vs hummocks), the relative age of the terrain after the deglaciation, and/or the vegetation. At another scale, we focused on mudboils as an agent of local disturbance in the vegetation and soil of the glacier foreland. The biomass and the amount of C and N in aboveground vegetation, surface litter, biological soil crust, and soil were generally increased with the stage of mudboils' inactivation. Biomass, C, and N in aboveground vegetation and surface litter were generally greater at moraine than at hummock, whereas those in biological soil crust and soil were greater at hummock. Principal component analysis identified two pathways, xeric and mesic ones on moraines and hummocks, respectively, of C and N accumulation both at the two spatial scales. These results suggested that the C and N accumulation was not linearly related to the time since deglaciation and that moisture condition, vegetation, and mudboil activity were locally important.

  4. Temperature and substrate controls on intra-annual variation in ecosystem respiration in two subarctic vegetation types

    DEFF Research Database (Denmark)

    Grogan, Paul; Jonasson, Sven Evert

    2005-01-01

    tundra vegetation types in northern Sweden through a full annual cycle. We used a plant biomass removal treatment to differentiate bulk soil organic matter respiration from total ecosystem respiration in each vegetation type. Plant-associated and bulk soil organic matter carbon pools each contributed...... the sensitivity of ecosystem respiration to intra-annual variations in soil temperature for both vegetation types, indicating that respiration derived from recent plant carbon fixation was more temperature sensitive than respiration from bulk soil organic matter carbon stores. Accurate assessment of the potential......Arctic ecosystems are important in the context of climate change because they are expected to undergo the most rapid temperature increases, and could provide a globally significant release of CO2 to the atmosphere from their extensive bulk soil organic carbon reserves. Understanding the relative...

  5. Distribution of crustal types in Canada Basin, Arctic Ocean

    Science.gov (United States)

    Chian, D.; Jackson, H. R.; Hutchinson, D. R.; Shimeld, J. W.; Oakey, G. N.; Lebedeva-Ivanova, N.; Li, Q.; Saltus, R. W.; Mosher, D. C.

    2016-11-01

    Seismic velocities determined from 70 sonobuoys widely distributed in Canada Basin were used to discriminate crustal types. Velocities of oceanic layer 3 (6.7-7.1 km/s), transitional (7.2-7.6 km/s) and continental crust (5.5-6.6 km/s) were used to distinguish crustal types. Potential field data supports the distribution of oceanic crust as a polygon with maximum dimensions of 340 km (east-west) by 590 km (north-south) and identification of the ocean-continent boundary (OCB). Paired magnetic anomalies are associated only with crust that has oceanic velocities. Furthermore, the interpreted top of oceanic crust on seismic reflection profiles is more irregular and sometimes shallower than adjacent transitional crust. The northern segment of the narrow Canada Basin Gravity Low (CBGL), often interpreted as a spreading center, bisects this zone of oceanic crust and coincides with the location of a prominent valley in seismic reflection profiles. Data coverage near the southern segment of CBGL is sparse. Velocities typical of transitional crust are determined east of it. Extension in this region, close to the inferred pole of rotation, may have been amagmatic. Offshore Alaska is a wide zone of thinned continental crust up to 300 km across. Published longer offset refraction experiments in the Basin confirm the depth to Moho and the lack of oceanic layer 3 velocities. Further north, toward Alpha Ridge and along Northwind Ridge, transitional crust is interpreted to be underplated or intruded by magmatism related to the emplacement of the High Arctic Large Igneous Province (HALIP). Although a rotational plate tectonic model is consistent with the extent of the conjugate magnetic anomalies that occupy only a portion of Canada Basin, it does not explain the asymmetrical configuration of the oceanic crust in the deep water portion of Canada Basin, and the unequal distribution of transitional and continental crust around the basin.

  6. Trends in the normalized difference vegetation index (NDVI) associated with urban development in arctic and subarctic Western Siberia

    Science.gov (United States)

    Outten, S.; Miles, V.; Ezau, I.

    2015-12-01

    Changes in normalized difference vegetation index (NDVI) in the high Arctic have been reliably documented, with widespread "greening" (increase in NDVI), specifically along the northern rim of Eurasia and Alaska. Whereas in West Siberia south of 65N, widespread "browning" (decrease in NDVI) has been noted, although the causes remain largely unclear. In this study we report results of statistical analysis of the spatial and temporal changes in NDVI around 28 major urban areas in the arctic and subarctic Western Siberia. Exploration and exploitation of oil and gas reserves has led to rapid industrialization and urban development in the region. This development has significant impact on the environment and particularly in the vegetation cover in and around the urbanized areas. The analysis is based on 15 years (2000-2014) of high-resolution (250 m) Moderate Resolution Imaging Spectroradiometer (MODIS) data acquired for summer months (June through August) over the entire arctic and subarctic Western Siberian region. The analysis shows that the NDVI background trends are generally in agreement with the trends reported in previous coarse-resolution NDVI studies. Our study reveals greening over the arctic (tundra and tundra-forest) part of the region. Simultaneously, the southern (boreal taiga forest) part is browning, with the more densely vegetation areas or areas with highest NDVI, particularly along Ob River showing strong negative trend. The unexpected and interesting finding of the study is statistically robust indication of the accelerated increase of NDVI ("greening") in the older urban areas. Many Siberian cities become greener even against the decrease in the NDVI background. Moreover, interannual variations of urban NDVI are not coherent with the NDVI background variability. We also find that in tundra zones, NDVI values are higher in a 5-10 km buffer zone around the city edge than in rural areas (40 km distance from the city edge), and in taiga in a 5-10 km

  7. Transitions in high-Arctic vegetation growth patterns and ecosystem productivity tracked with automated cameras from 2000 to 2013

    DEFF Research Database (Denmark)

    Westergaard-Nielsen, Andreas; Lund, Magnus; Pedersen, Stine Højlund

    2017-01-01

    Climate-induced changes in vegetation phenology at northern latitudes are still poorly understood. Continued monitoring and research are therefore needed to improve the understanding of abiotic drivers. Here we used 14 years of time lapse imagery and climate data from high-Arctic Northeast...... Greenland to assess the seasonal response of a dwarf shrub heath, grassland, and fen, to inter-annual variation in snow-cover, soil moisture, and air and soil temperatures. A late snow melt and start of growing season is counterbalanced by a fast greenup and a tendency to higher peak greenness values. Snow...

  8. The Influence of Vegetation Canopy Structure on Active Layer Thaw Within the Sub-Arctic Discontinuous Permafrost Zone

    Science.gov (United States)

    Chasmer, L.; Quinton, W.; Hopkinson, C.; Petrone, R.; Whittington, P.

    2009-05-01

    Much of the sub-arctic discontinuous permafrost zone is dominated by a range in peatland ecosystems, each with their own characteristic soil frost dynamics. Soil thaw within the discontinuous permafrost zones of the Canadian sub-arctic is driven by the surface energy balance. The following study examines the influence of canopy structure on frost table (FT) depth and rates of thaw by: 1. relating measurements of FT depth to canopy structure using airborne scanning light detection and ranging (lidar) and hemispherical photographs taken below vegetated canopies; and 2. quantifying the spatial influences of canopy structural characteristics on the radiation balance (direct and diffuse incident radiation) within raised peat plateaus, connected bogs, fens, and isolated bogs. The results of this study indicate that peat plateaus, being characterised by greater vegetation fractional cover, typically have shallower FT depths (r2 = 0.5, p = 0.03) than locations with lower biomass. Further, average ground surface elevation and canopy height are related to rates of FT thaw (r2 = 0.73, p indicates that rates of thaw at the edges of peat plateaus and areas surrounding isolated bogs will be exacerbated by increased incident radiation and less shadowing by the canopy, leading to the conversion of peat plateaus to fens or bogs. This hypothesis is tested by comparing the change in peat plateau area coverage in 2000 and 2008 using classified IKONOS imagery (2000) and airborne lidar (2008).

  9. Alternatives to sowing vegetable type soybeans

    Directory of Open Access Journals (Sweden)

    Edcarlos Mannfredini

    1998-08-01

    Full Text Available Today, soybean crops of the Tamba Kurodaisu cultivar are sown in beds prior to transplantation to the field. This planting system has caused crop failure due to damage to the root system. An experiment to test different sowing alternatives to obtain plantlets for cropping of food type big seeded soybean was set up with the following treatments: sowing in beds; sowing in 130 cm³ newspaper cups; sowing in test tubes of volumes of 30 cm³, 60 cm³ and 70 cm³; sowing in 70 cm³ disposable plastic cups; sowing on 90 cm³ styrofoam trays. A randomized complete block design was used, and the following traits were assessed: germination percentage; number of days to flowering; plant height at flowering; number of days to maturity; plant height at maturity; number of seeds per plant; individual plant yield; weight of a hundred seeds. Results should that three methods could be used to set up Tamba Kurodaisu cultivar crops: sowing in disposable plastic cups, sowing in beds with later transplant, or direct sowing in the field.Atualmente, as lavouras com o cultivar Tamba Kurodaisu são semeadas em canteiros, para posterior transplante no campo. Este sistema tem causado falhas na lavoura, por ocorrer danificação no sistema radicular. Com o objetivo de testar diferentes alternativas de semeadura para obtenção de mudas visando a implantação de lavouras de soja tipo alimento, com sementes graúdas, instalou-se um experimento com os seguintes tratamentos: Semeadura em canteiros; Semeadura em copos de jornal, com volume (V igual a 130 cm³; Semeadura em tubetes, com V = 30 cm³; V = 60 cm³; V = 70 cm³; Semeadura em copos plásticos descartáveis, com V = 70 cm³; Semeadura em bandejas de isopor, com V = 90cm³. O delineamento utilizado foi blocos casualizados, tendo sido avaliados os seguintes caracteres: Porcentagem de germinação; Número de plantas por parcela; Número de dias para o florescimento; Altura da planta no florescimento; Número de dias

  10. REPEATABILITY OF THE FRENCH HIGHER VEGETATION TYPES ACCORDING

    Directory of Open Access Journals (Sweden)

    H. BRISSE

    1998-04-01

    Full Text Available Higher vegetation types are generally determined by successive approximations and defined by a common consent. Instead, they might be statistically determined and repeated, according to a numerical method called ‘socio-ecology’. This method deals only with floristical data, but gives them an ecological meaning by a previous calibration of the relations between plants, computed as ecological indices. It is applied to a pair of two homologous samples, each having 2.000 relevés and coming from the 60.000 relevés stored in the French data bank ‘Sophy’. Each sample covers the main ecological gradients of the bank, it defines a hierarchy of vegetation types and it explains half the peculiarity of a type with only 10 to 30 discriminant plants, out of the 5.000 plants observed in the relevés. Results : 1 The discriminant plants may characterize the vegetation types, including the higher ones, in a coherent and readable form. 2 In the two independent classifications, having different structures, the same vegetation types are repeated. They are the reciprocal nearest types, in the socio-ecological space. Though the two classifications have no one relevé in common, the repeated types have nearly the same discriminant plants. 3 At the highest level, two clear-cut main types show the difference between light and shadow. The same herbaceous discriminant plants, for a type, and the ligneous or sciaphilous ones, for the other, have similar fidelities and constancies in the two classifications. 4 Such a numerical agreement, instead of common consent, appears again in the sub-types, which remind the classical ones, but which are repeatable.

  11. Evaluation of Polarimetric SAR Decomposition for Classifying Wetland Vegetation Types

    Directory of Open Access Journals (Sweden)

    Sang-Hoon Hong

    2015-07-01

    Full Text Available The Florida Everglades is the largest subtropical wetland system in the United States and, as with subtropical and tropical wetlands elsewhere, has been threatened by severe environmental stresses. It is very important to monitor such wetlands to inform management on the status of these fragile ecosystems. This study aims to examine the applicability of TerraSAR-X quadruple polarimetric (quad-pol synthetic aperture radar (PolSAR data for classifying wetland vegetation in the Everglades. We processed quad-pol data using the Hong & Wdowinski four-component decomposition, which accounts for double bounce scattering in the cross-polarization signal. The calculated decomposition images consist of four scattering mechanisms (single, co- and cross-pol double, and volume scattering. We applied an object-oriented image analysis approach to classify vegetation types with the decomposition results. We also used a high-resolution multispectral optical RapidEye image to compare statistics and classification results with Synthetic Aperture Radar (SAR observations. The calculated classification accuracy was higher than 85%, suggesting that the TerraSAR-X quad-pol SAR signal had a high potential for distinguishing different vegetation types. Scattering components from SAR acquisition were particularly advantageous for classifying mangroves along tidal channels. We conclude that the typical scattering behaviors from model-based decomposition are useful for discriminating among different wetland vegetation types.

  12. How spatial variation in areal extent and configuration of labile vegetation states affect the riparian bird community in Arctic tundra.

    Science.gov (United States)

    Henden, John-André; Yoccoz, Nigel G; Ims, Rolf A; Langeland, Knut

    2013-01-01

    The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond rapidly to both abiotic and biotic environmental drivers. Our aim was to assess how large-scale spatial variation in willow thicket areal extent, configuration and habitat structure affected bird abundance, occupancy rates and species richness so as to provide an empirical basis for predicting the outcome of environmental change for riparian tundra bird communities. Based on a 4-year count data series, obtained through a large-scale study design in low arctic tundra in northern Norway, statistical hierarchical community models were deployed to assess relations between habitat configuration and bird species occupancy and community richness. We found that species abundance, occupancy and richness were greatly affected by willow areal extent and configuration, habitat features likely to be affected by intense ungulate browsing as well as climate warming. In sum, total species richness was maximized in large and tall willow patches of small to intermediate degree of fragmentation. These community effects were mainly driven by responses in the occupancy rates of species depending on tall willows for foraging and breeding, while species favouring other vegetation states were not affected. In light of the predicted climate driven willow shrub encroachment in riparian tundra habitats, our study predicts that many bird species would increase in abundance, and that the bird community as a whole could become enriched. Conversely, in tundra regions where overabundance of large herbivores leads to decreased areal extent, reduced height and increased fragmentation of willow thickets

  13. How spatial variation in areal extent and configuration of labile vegetation states affect the riparian bird community in Arctic tundra.

    Directory of Open Access Journals (Sweden)

    John-André Henden

    Full Text Available The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond rapidly to both abiotic and biotic environmental drivers. Our aim was to assess how large-scale spatial variation in willow thicket areal extent, configuration and habitat structure affected bird abundance, occupancy rates and species richness so as to provide an empirical basis for predicting the outcome of environmental change for riparian tundra bird communities. Based on a 4-year count data series, obtained through a large-scale study design in low arctic tundra in northern Norway, statistical hierarchical community models were deployed to assess relations between habitat configuration and bird species occupancy and community richness. We found that species abundance, occupancy and richness were greatly affected by willow areal extent and configuration, habitat features likely to be affected by intense ungulate browsing as well as climate warming. In sum, total species richness was maximized in large and tall willow patches of small to intermediate degree of fragmentation. These community effects were mainly driven by responses in the occupancy rates of species depending on tall willows for foraging and breeding, while species favouring other vegetation states were not affected. In light of the predicted climate driven willow shrub encroachment in riparian tundra habitats, our study predicts that many bird species would increase in abundance, and that the bird community as a whole could become enriched. Conversely, in tundra regions where overabundance of large herbivores leads to decreased areal extent, reduced height and increased fragmentation

  14. Qualitative parameters of non-traditional types of vegetables

    Directory of Open Access Journals (Sweden)

    Eva Kudrnáčová

    2015-08-01

    Full Text Available The main aim of this study was to determine selected quality indicators of non-traditional types of leafy vegetables. Mizuna (Brassica rapa japonica, Chinese mustard (Brassica juncea, edible chrysanthemum (Chrysanthemum coronarium and arugula (Eruca sativa belonged among the selected species of vegetables. During the one-year experiment, spring and autumn sowing was carried out for these species of vegetables. The measured quality parameters were the content of nitrates and ascorbic acid. Sampling was done in the morning and in the laboratory, the samples were further processed according to the type of determination. To determine the content of nitrates and ascorbic acid, leaves were removed from plants. The filtrate from the leaves was then prepared. Determination of nitrates and ascorbic acid was carried out using a special test strip and device Rqflex plus 10. The results of measurement of both sowing varieties were compared. Total nitrate content was higher up to 22% in plants sown in the autumn except edible chrysanthemum (Chrysanthemum coronarium. The highest content was recorded in arugula (Eruca sativa, which was recently implemented to the studies of the European Union and for which there were set the limits of nitrates. Overall, the nitrate content ranged from 221 to 334 ppm in spring varieties and from 249 to 384 mg/kg in autumn varieties. Ascorbic acid content was very high in Chinese mustard (Brassica juncea, edible chrysanthemum (Chrysanthemum coronarium and arugula (Eruca sativa in both spring and autumn varieties. Values of ascorbic acid ranged from 839 in autumn sowing up to 2909 mg/kg in spring sowing. These non-traditional types of leafy vegetables could be included among the other importants sources of vitamin C in the future.  

  15. Seasonal contributions of vegetation types to suburban evapotranspiration

    Science.gov (United States)

    Peters, Emily B.; Hiller, Rebecca V.; McFadden, Joseph P.

    2011-03-01

    Evapotranspiration is an important term of energy and water budgets in urban areas and is responsible for multiple ecosystem services provided by urban vegetation. The spatial heterogeneity of urban surface types with different seasonal water use patterns (e.g., trees and turfgrass lawns) complicates efforts to predict and manage urban evapotranspiration rates, necessitating a surface type, or component-based, approach. In a suburban neighborhood of Minneapolis-Saint Paul, Minnesota, United States, we simultaneously measured ecosystem evapotranspiration and its main component fluxes using eddy covariance and heat dissipation sap flux techniques to assess the relative contribution of plant functional types (evergreen needleleaf tree, deciduous broadleaf tree, cool season turfgrass) to seasonal and spatial variations in evapotranspiration. Component-based evapotranspiration estimates agreed well with measured water vapor fluxes, although the imbalance between methods varied seasonally from a 20% overestimate in spring to an 11% underestimate in summer. Turfgrasses represented the largest contribution to annual evapotranspiration in recreational and residential land use types (87% and 64%, respectively), followed by trees (10% and 31%, respectively), with the relative contribution of plant functional types dependent on their fractional cover and daily water use. Recreational areas had higher annual evapotranspiration than residential areas (467 versus 324 mm yr-1, respectively) and altered seasonal patterns of evapotranspiration due to greater turfgrass cover (74% versus 34%, respectively). Our results suggest that plant functional types capture much of the variability required to predict the seasonal patterns of evapotranspiration among cities, as well as differences in evapotranspiration that could result from changes in climate, land use, or vegetation composition.

  16. Effects of large herbivores on biodiversity of vegetation and soil microarthropods in low Arctic Greenland

    DEFF Research Database (Denmark)

    Aastrup, Peter; Raundrup, Katrine; Feilberg, Jon;

    This report summarizes the results of a project that aims at documenting long term effects of grazing by comparing baseline data inside and outside exclosures. We collected data on vascular plants, mosses, lichens, microarthropod abundance and food-web structure, soil nutrients, decomposition......, and soil temperature. Data provide a significant basis for understanding the interaction between large herbivores and vegetation in Greenland. The report contains documentation of data collected in 2009 and 2012 as well as documentation of data from 1984-2004 made available by Jon Feilberg....

  17. Spatial variation in landscape-level CO2 and CH4 fluxes from arctic coastal tundra: influence from vegetation, wetness, and the thaw lake cycle.

    Science.gov (United States)

    Sturtevant, Cove S; Oechel, Walter C

    2013-09-01

    Regional quantification of arctic CO2 and CH4 fluxes remains difficult due to high landscape heterogeneity coupled with a sparse measurement network. Most of the arctic coastal tundra near Barrow, Alaska is part of the thaw lake cycle, which includes current thaw lakes and a 5500-year chronosequence of vegetated thaw lake basins. However, spatial variability in carbon fluxes from these features remains grossly understudied. Here, we present an analysis of whole-ecosystem CO2 and CH4 fluxes from 20 thaw lake cycle features during the 2011 growing season. We found that the thaw lake cycle was largely responsible for spatial variation in CO2 flux, mostly due to its control on gross primary productivity (GPP). Current lakes were significant CO2 sources that varied little. Vegetated basins showed declining GPP and CO2 sink with age (R(2) = 67% and 57%, respectively). CH4 fluxes measured from a subset of 12 vegetated basins showed no relationship with age or CO2 flux components. Instead, higher CH4 fluxes were related to greater landscape wetness (R(2) = 57%) and thaw depth (additional R(2) = 28%). Spatial variation in CO2 and CH4 fluxes had good satellite remote sensing indicators, and we estimated the region to be a small CO2 sink of -4.9 ± 2.4 (SE) g C m(-2) between 11 June and 25 August, which was countered by a CH4 source of 2.1 ± 0.2 (SE) g C m(-2) . Results from our scaling exercise showed that developing or validating regional estimates based on single tower sites can result in significant bias, on average by a factor 4 for CO2 flux and 30% for CH4 flux. Although our results are specific to the Arctic Coastal Plain of Alaska, the degree of landscape-scale variability, large-scale controls on carbon exchange, and implications for regional estimation seen here likely have wide relevance to other arctic landscapes.

  18. WETLAND TYPES AND ASSOCIATE VEGETATION IN NEPAL:AN OVERVIEW

    Institute of Scientific and Technical Information of China (English)

    Mohan Siwakoti

    2007-01-01

    Wetland is the transitional zone between the permanently wet and dry environment and shares the characteristics of the environment. Wetland is not yet to be classified unambiguously as either aquatic or terrestrial. However, the Ramsar Convention adopts an extremely broad approach in determining the wetland; as a result, several varieties of habitat types are included under the wetland definition. Wetlands are among the world's most productive ecosystems and provide a wide variety of goods and services. Nepal lies on the southern slopes of central Himalayas and occupies a total area of 147 181 km2 between the latitudes 26°22′ N and 30°27′ N and the longitudes 80°40′ E and 88°12′ E. The diverse landscape (60-8 848 m) and bioclimatic conditions (alpine to tropical) of the country provide a unique niche for different types of wetlands. These are distributed from high altitudinal glacial lakes to hot springs, ponds, ox-bow lakes to river floodplains, marshes and swamps. The country has 15 types of inland freshwater natural wetlands as classified by the Ramsar Convention. These wetlands house several species of rare and endangered flora and fauna. The present paper attempts to highlight the various types of wetlands in Nepal with associate vegetation.

  19. Mapping and characterizing the vegetation types of the Democratic Republic of Congo using SPOT VEGETATION time series

    Science.gov (United States)

    Vancutsem, C.; Pekel, J.-F.; Evrard, C.; Malaisse, F.; Defourny, P.

    2009-02-01

    The need for quantitative and accurate information to characterize the state and evolution of vegetation types at a national scale is widely recognized. This type of information is crucial for the Democratic Republic of Congo, which contains the majority of the tropical forest cover of Central Africa and a large diversity of habitats. In spite of recent progress in earth observation capabilities, vegetation mapping and seasonality analysis in equatorial areas still represent an outstanding challenge owing to high cloud coverage and the extent and limited accessibility of the territory. On one hand, the use of coarse-resolution optical data is constrained by performance in the presence of cloud screening and by noise arising from the compositing process, which limits the spatial consistency of the composite and the temporal resolution. On the other hand, the use of high-resolution data suffers from heterogeneity of acquisition dates, images and interpretation from one scene to another. The objective of the present study was to propose and demonstrate a semi-automatic processing method for vegetation mapping and seasonality characterization based on temporal and spectral information from SPOT VEGETATION time series. A land cover map with 18 vegetation classes was produced using the proposed method that was fed by ecological knowledge gathered from botanists and reference documents. The floristic composition and physiognomy of each vegetation type are described using the Land Cover Classification System developed by the FAO. Moreover, the seasonality of each class is characterized on a monthly basis and the variation in different vegetation indicators is discussed from a phenological point of view. This mapping exercise delivers the first area estimates of seven different forest types, five different savannas characterized by specific seasonality behavior and two aquatic vegetation types. Finally, the result is compared to two recent land cover maps derived from

  20. Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro.

    Science.gov (United States)

    Rutten, Gemma; Ensslin, Andreas; Hemp, Andreas; Fischer, Markus

    2015-01-01

    In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866-4550 m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies.

  1. Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro.

    Directory of Open Access Journals (Sweden)

    Gemma Rutten

    Full Text Available In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866-4550 m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies.

  2. Dynamic surface soil components of land and vegetation types in Kebbi State Nigeria

    Directory of Open Access Journals (Sweden)

    Suleiman Usman

    2016-04-01

    Full Text Available Land and vegetation are important components of soil and provides many benefits to surface soil including protection against erosion, climate change impact and unacceptable degradation of soil particles. Visual Soil Assessment was used as a mechanism to assess and classify the land and vegetation types of some agricultural sites in Kebbi State, Nigeria. The aim was to get better understanding of the environmental soil function for sustainable crop production in dryland and fadama areas of the State. The assessment was able to put together combinations of different vegetation types and land age classes. It is valued that the land age classes possessed the characteristics of Holocene-natural, Holocene-anthropogeomorphic, Holocene-young-natural, young-anthropogeomorphic, very-young anthropogeomorphic and very-young natural. However, the vegetation types could be related to evergreen forest, short medium forest (scattered clustered, dwarf vegetation (scattered isolated, grass vegetation, thick vegetation, stony-grass vegetation (scattered sparse and short-length vegetation. The assessment provides an improve understanding of the current status of land and vegetation conditions of the study area and suggested regular soil management for sustainable crop production in the State.

  3. Water retention and evapotranspiration of green roofs and possible natural vegetation types

    NARCIS (Netherlands)

    Metselaar, K.

    2012-01-01

    Matching vegetation to growing conditions on green roofs is one of the options to increase biodiversity in cities. A hydrological model has been applied to match the hydrological requirements of natural vegetation types to roof substrate parameters and to simulate moisture stress for specific substr

  4. Using Dehydrated Vegetables in Some Brown Bread Types

    Directory of Open Access Journals (Sweden)

    Simona Man

    2013-11-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Expanding the range of bakery products in terms of producing supplemented or dietetic products has been an increasingly important trend in contemporary baking. Bakery products as basic and popular food, could be used in the prevention of nutritive deficiencies of many important nutrients, by supplementing the products with biologically valuable ingredients. Such ingredients are dehydrated vegetables in the form of powder. For establishing the bread quality, a special importance shows it’s chemical composition, because the substances that enter in it’s constitution serve to obtaining the energy necessary to the human body. Beside the chemical composition, the bread quality and alimentary use, respectively, depends a large measure on a series of signs: flavor and taste, external appearance, crumb porosity and texture, breads’ volume. This paper belongs to a more complex study, which aims are obtaining some bread assortments with high nutritional value, and improving their sensorial and rheological features, by adding dehydrated vegetables at different levels 4% potato flakes, 2% dehydrated onion, 0.5% dehydrated garlic and 2% dehydrated leek.

  5. Major vegetation types, climatological data, and solar radiation calculations for Colorado's Brush Creek valley

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, C.D.; Lambeth, R.; Allwine, K.J.

    1987-04-01

    In this report we present information on the vegetative cover, climate, and solar radiation for the Brush Creek valley. A brief vegetative survey was made on October 3, 1984, to identify the vegetation types in the lowest 8 km of the valley; the reader is cautioned that this included only a small part of the Brush Creek valley. The intent was to identify the principal vegetation types, with no attempt to use available scientific sampling techniques to determine accurate relative frequencies of the vegetation types. Nevertheless, the site survey has allowed us to identify the major species of vegetation, and to make reasonably accurate differentiations of both major vegetation types on valley surfaces (the valley floor, two sidewalls, and ridgetops) and the relative abundance of major vegetation types on each surface.

  6. Effects of sample mass and macrofossil type on radiocarbon dating of arctic and boreal lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Oswald, W W; Anderson, P M; Brown, T A; Brubaker, L B; Hu, F S; Lozhkin, A V; Tinner, W; Kaltenrieder, P

    2006-05-29

    Dating lake sediments by accelerator mass spectrometry (AMS) {sup 14}C analysis of plant macrofossils overcomes one of the main problems associated with dating bulk sediment samples, the presence of old organic matter. Even so, many AMS dates from arctic and boreal sites appear to misrepresent the age of the sediment. To understand the nature of these apparent dating anomalies better, we conducted a series of {sup 14}C dating experiments using samples from Alaskan and Siberian lake-sediment cores. First, to test whether our analytical procedures introduced a sample-mass bias, we obtained {sup 14}C dates for different-sized pieces of single woody macrofossils. In these sample-mass experiments, sized statistically equivalent ages were found for samples as small as 0.05 mg C. Second, to assess whether macrofossil type influenced dating results, we conducted sample-type experiments in which {sup 14}C dates were obtained for different macrofossil types sieved from the same depth in the sediment. We dated materials from multiple levels in sediment cores from Upper Capsule Lake (North Slope, northern Alaska) and Grizzly Lake (Copper River Basin, southern Alaska), and from single depths in other records from northern Alaska. In several of the experiments there were significant discrepancies between dates for different plant tissues, and in most cases wood and charcoal were older than other macrofossil types, usually by several hundred years. This pattern suggests that {sup 14}C dates for woody macrofossils may misrepresent the age of the sediment by centuries, perhaps due to their longer terrestrial residence time and the potential in-built age of long-lived plants. This study identifies why some {sup 14}C dates appear to be inconsistent with the overall age-depth trend of a lake-sediment record, and it may guide the selection of {sup 14}C samples in future studies.

  7. Divergent Impacts of Two Cattle Types on Vegetation in Coastal Meadows: Implications for Management.

    Science.gov (United States)

    Laurila, Marika; Huuskonen, Arto; Pesonen, Maiju; Kaseva, Janne; Joki-Tokola, Erkki; Hyvärinen, Marko

    2015-11-01

    The proportion of beef cattle in relation to the total number of cattle has increased in Europe, which has led to a higher contribution of beef cattle in the management of semi-natural grasslands. Changes in vegetation caused by this change in grazers are virtually unexplored so far. In the present study, the impacts of beef and dairy cattle on vegetation structure and composition were compared on Bothnian Bay coastal meadows. Vegetation parameters were measured in seven beef cattle, six dairy heifer pastures, and in six unmanaged meadows. Compared to unmanaged meadows, vegetation in grazed meadows was significantly lower in height and more frequently colonized by low-growth species. As expected, vegetation grazed by beef cattle was more open than that on dairy heifer pastures where litter cover and proportion of bare ground were in the same level as in the unmanaged meadows. However, the observed differences may have in part arisen from the higher cattle densities in coastal meadows grazed by beef cattle than by dairy heifers. The frequencies of different species groups and the species richness values of vegetation did not differ between the coastal meadows grazed by the two cattle types. One reason for this may be the relatively short management history of the studied pastures. The potential differences in grazing impacts of the two cattle types on vegetation structure can be utilized in the management of coastal meadows for species with divergent habitat requirements.

  8. Simulation of maximum light use efficiency for some typical vegetation types in China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Maximum light use efficiency (εmax) is a key parameter for the estimation of net primary productivity (NPP) derived from remote sensing data. There are still many divergences about its value for each vegetation type. The εmax for some typical vegetation types in China is simulated using a modified least squares function based on NOAA/AVHRR remote sensing data and field-observed NPP data. The vegetation classification accuracy is introduced to the process. The sensitivity analysis of εmax to vegetation classification accuracy is also conducted. The results show that the simulated values of εmax are greater than the value used in CASA model, and less than the values simulated with BIOME-BGC model. This is consistent with some other studies. The relative error of εmax resulting from classification accuracy is -5.5%―8.0%. This indicates that the simulated values of εmax are reliable and stable.

  9. Stochastic daily modeling of arctic tundra ecosystems

    Science.gov (United States)

    Erler, A.; Epstein, H. E.; Frazier, J.

    2011-12-01

    ArcVeg is a dynamic vegetation model that has simulated interannual variability of production and abundance of arctic tundra plant types in previous studies. In order to address the effects of changing seasonality on tundra plant community composition and productivity, we have uniquely adapted the model to operate on the daily timescale. Each section of the model-weather generation, nitrogen mineralization, and plant growth dynamics-are driven by daily fluctuations in simulated temperature conditions. These simulation dynamics are achieved by calibrating stochastic iterative loops and mathematical functions with raw field data. Air temperature is the fundamental driver in the model, parameterized by climate data collected in the field across numerous arctic tundra sites, and key daily statistics are extracted (mean and standard deviation of temperature for each day of the year). Nitrogen mineralization is calculated as an exponential function from the simulated temperature. The seasonality of plant growth is driven by the availability of nitrogen and constrained by historical patterns and dynamics of the remotely sensed normalized difference vegetation index (NDVI), as they pertain to the seasonal onset of growth. Here we describe the methods used for daily weather generation, nitrogen mineralization, and the daily competition among twelve plant functional types for nitrogen and subsequent growth. This still rather simple approach to vegetation dynamics has the capacity to generate complex relationships between seasonal patterns of temperature and arctic tundra vegetation community structure and function.

  10. [Reproductive phenology of three vegetation types from a coastal plain of Paraguana Penninsula, Venezuela].

    Science.gov (United States)

    Lemus-Jiménez, Luis José; Ramírez, Nelson

    2002-01-01

    Reproductive phenology of 51 plant species was evaluated according to life form and vegetation types in a coastal plain of the Paraguaná Peninsula, Estado Falcón, Venezuela. Plant species distribution according to three vegetation types (herbaceous littoral, herbaceous psamophil, and mangrove area) was determined. Life form frequency was different according to vegetation type. Herbaceous littoral and herbaceous psamophil vegetation were dominated by herbaceous species; woody species were mostly frequent in the mangrove vegetation. Phenological data revealed that 14 (27.5%) plant species flower and fruit year-round; 23 (45.1%) plant species flower and fruit at the beginning of the wet season; seven (13.7%) plant species flower at the end of wet season, and seven (13.7%) more flower at the beginning of the dry season. Flowsring and fruiting phenology showed similar frequency distribution during the year; reproductive phenology was independent of life forms. Flowering and fruiting peaks occurred during the rainy season and the beginning of the dry season for trees and perennial herbs, and from one to three months later for shrubs and annual herbs. The lowest proportion of flowering and fruiting occurred before rain increase for all life forms. Flowering and fruiting phenologies were similar for the three vegetation types evaluated: flowering peak occurred during the lowest value of precipitation, three to four months after precipitation peak, and fruiting peak occurred four months later from the precipitation peak. These results suggest that flowering and fruiting phenology were not affected by life form and vegetation types. The peaks of flowering and fruiting during the lowest values of precipitation may be considered as a slow and late response to the precipitation maximum, and to the proximity between maximum and minimum of precipitation.

  11. Monitoring of fire incidences in vegetation types and Protected Areas of India: Implications on carbon emissions

    Science.gov (United States)

    Reddy, C. Sudhakar; Padma Alekhya, V. V. L.; Saranya, K. R. L.; Athira, K.; Jha, C. S.; Diwakar, P. G.; Dadhwal, V. K.

    2017-02-01

    Carbon emissions released from forest fires have been identified as an environmental issue in the context of global warming. This study provides data on spatial and temporal patterns of fire incidences, burnt area and carbon emissions covering natural vegetation types (forest, scrub and grassland) and Protected Areas of India. The total area affected by fire in the forest, scrub and grasslands have been estimated as 48765.45, 6540.97 and 1821.33 km 2, respectively, in 2014 using Resourcesat-2 AWiFS data. The total CO 2 emissions from fires of these vegetation types in India were estimated to be 98.11 Tg during 2014. The highest emissions were caused by dry deciduous forests, followed by moist deciduous forests. The fire season typically occurs in February, March, April and May in different parts of India. Monthly CO 2 emissions from fires for different vegetation types have been calculated for February, March, April and May and estimated as 2.26, 33.53, 32.15 and 30.17 Tg, respectively. Protected Areas represent 11.46% of the total natural vegetation cover of India. Analysis of fire occurrences over a 10-year period with two types of sensor data, i.e., AWiFS and MODIS, have found fires in 281 (out of 614) Protected Areas of India. About 16.78 Tg of CO 2 emissions were estimated in Protected Areas in 2014. The natural vegetation types of Protected Areas have contributed for burnt area of 17.3% and CO 2 emissions of 17.1% as compared to total natural vegetation burnt area and emissions in India in 2014. 9.4% of the total vegetation in the Protected Areas was burnt in 2014. Our results suggest that Protected Areas have to be considered for strict fire management as an effective strategy for mitigating climate change and biodiversity conservation.

  12. Monitoring of fire incidences in vegetation types and Protected Areas of India: Implications on carbon emissions

    Indian Academy of Sciences (India)

    C Sudhakar Reddy; V V L Padma Alekhya; K R L Saranya; K Athira; C S Jha; P G Diwakar; V K Dadhwal

    2017-02-01

    Carbon emissions released from forest fires have been identified as an environmental issue in the context of global warming. This study provides data on spatial and temporal patterns of fire incidences, burnt area and carbon emissions covering natural vegetation types (forest, scrub and grassland) and Protected Areas of India. The total area affected by fire in the forest, scrub and grasslands have been estimated as 48765.45, 6540.97 and 1821.33 km², respectively, in 2014 using Resourcesat-2 AWiFS data. The total CO₂ emissions from fires of these vegetation types in India were estimated to be 98.11 Tg during 2014. The highest emissions were caused by dry deciduous forests, followed by moist deciduous forests. The fire season typically occurs in February, March, April and May in different parts of India. Monthly CO₂ emissions from fires for different vegetation types have been calculated for February, March, April and May and estimated as 2.26, 33.53, 32.15 and 30.17 Tg, respectively. Protected Areas represent 11.46% of the total natural vegetation cover of India. Analysis of fire occurrences over a 10-year period with two types of sensor data, i.e., AWiFS and MODIS, have found fires in 281 (out of 614) Protected Areas of India. About 16.78 Tg of CO₂ emissions were estimated in Protected Areas in 2014. The natural vegetation types of Protected Areas have contributed for burnt area of 17.3% and CO₂ emissions of 17.1% as compared to total natural vegetation burnt area and emissions in India in 2014. 9.4% of the total vegetation in the Protected Areas was burnt in 2014. Our results suggest that Protected Areas have to be considered for strict fire management as an effective strategy for mitigating climate change and biodiversity conservation.

  13. Differences in hydrological responses for different vegetation types on a steep slope on the Loess Plateau, China

    Science.gov (United States)

    Duan, Liangxia; Huang, Mingbin; Zhang, Luodan

    2016-06-01

    Extensive vegetation restoration practices have been implemented to control soil erosion on the Loess Plateau, China. However, no strict guidelines are available to determine the most suitable plant species for vegetation restoration within a given area. The objective of this study was to quantify the changes of each component (soil water storage, surface runoff, and actual evapotranspiration) of a water balance model and soil loss over time under eight different vegetation types, and to further determine the optimal vegetation type for soil and water conservation and sustainable ecological restoration on the steep slopes (>25°) on the Loess Plateau. The results indicated that vegetation type substantially affected soil water storage and that the greatest soil water storage in both the shallow (0-2 m) and the deep soil layers (2-5 m) occurred under Bothriochloa ischaemum L. (BOI). Vegetation type also affected surface runoff and soil losses. The most effective vegetation types for reducing soil erosion were BOI and Sea-buckthorn (Hippophae rhamnoides L.), while Chinese pine (Pinus tabulaeformis Carr.) and Chinese pine + Black locust (Robinia pseudoacacia L.) were the most ineffective types. Soil water dynamics and evapotranspiration varied considerably among the different vegetation types. A soil water surplus was only found under BOI, while insufficient water replenishment existed under the other seven vegetation types. The higher water consumption rates of the seven vegetation types could result in soil desiccation, which could lead to severe water stresses that would adversely affect plant growth. This study suggested that both vegetation type and its effect on controlling soil erosion should be considered when implementing vegetation restoration and that BOI should be highly recommended for vegetation restoration on the steep slopes of the Loess Plateau. A similar approach to the one used in this study could be applied to other regions of the world confronted

  14. Soil Respiration Responses to Variation in Temperature Treatment and Vegetation Type

    Science.gov (United States)

    Liu, S.; Pavao-zuckerman, M.

    2013-12-01

    Complex linkages exist between terrestrial vegetation, soil moisture, soil organic matter (SOM), local climate, and soil microorganisms. Thus, large-scale changes in vegetation, such as the woody plant encroachment observed in many historically semiarid and arid grasslands worldwide, could potentially alter the flux of carbon from soil reserves to the atmosphere. Mathematical models that attempt to project the long-term impact of vegetative shifts on soil fluxes largely rely on assumptions such as first-order donor control rather than incorporate the biological aspects of soil respiration such as microbial activity. To examine the impact of vegetation type on soil physicochemical properties and soil microbial respiration and provide experimental data to refine existing predictive models, we compared soil (ground basalt from northern Arizona) in mesocosms established with no vegetation, velvet mesquites (Prosopis velutina; woody shrub), or sideoats gramas (Bouteloua curtipendula; grass) for 2 years, The temperature sensitivity of soil respiration was examined by incubating soil (0-10 and 10-30 cm depth fractions) from each vegetation treatment at 10, 20, 30, and 40 °C for 24 hours. Vegetated soils contained more SOM (~0.1% for mesquite and grass mesocosms) than non-vegetated soils (~0.02%). Respiration rates were generally highest from grass-established soils, intermediate from mesquite-established soils, and lowest from non-vegetated soils. Respiration rates of samples incubated without the addition of substrate peaked at approximately 30 °C, whereas respiration rates of samples incubated with dextrose were highest at 40 °C. Further, the respiration assays suggest that while respiration rates are overall higher in grass-established soils, mesquite-established soils are more temperature sensitive which may have significant implications in the context of global warming and current fire management practices.

  15. THE FORMATION OF ENTS ADAPTIVE REACTIONS DEPENDING ON THE TYPE OF PSYCHO-VEGETATIVE REGULATION

    Directory of Open Access Journals (Sweden)

    E. M. Kazin

    2014-01-01

    Full Text Available The purpose of the students (12 to 15 years old examination was to identify the integrative criteria of assessing the nature of the functional relationships between the parameters of the psychosocial and physiological adaptation of students, depending on age, individual-typological peculiarities of vegetative regulation, personal potential at different stages of school education.The study of the characteristics of vegetative regulation of the cardiovascular system was made with a help of an automatic cardiac-rhythm programs. The research of psychophysiological parameters was fulfiled using an automatic complex. The measurement of the speed of simple visual-motor reaction (PSMR, reaction to a moving object (WFD, the level of functional mobility of nervous processes (WFP and health brain (DDM were made before. Features psychosocial adaptation was analyzed using 8-color Luscher test.All examinee were divided into three groups on the basis of the statistical characteristics of the cardiac rhythm by the tone source autonomic tone: “vagotonia” (with a predominance of parasympathetic sistems, “somatotonic” (with domination of the sympatholytic effects, “atonic” (balanced type of vegetative nervous system.Based on the analysis of psychodynamic, neurodynamic and vegetative functions showed that students with initial vagotonies tone are characterized by high levels of situational and personal anxiety, low psychosocial adaptation, decreased activity of neurodynamic functions and psychodynamic processes in the learning dynamics, whereas the individuals with dominance of sympatotonics type regulation have high level of neurodynamic processes, psychosocial adaptation, against the background of significant stress mechanisms of vegetative regulation.Students with initial vegetative tone demonstrate a sufficient level of psychosocial adaptation, activity psychodynamic and neuromotor processes, accompanied by the preservation of the functionality of

  16. Effects of Spatial Heterogeneity in Rainfall and Vegetation Type on Soil Moisture and Evapotranspiration

    CERN Document Server

    Puma, Michael J; Rodriguez-Iturbe, Ignacio; Nordbotten, Jan M; Guswa, Andrew J; Kavetski, Dmitri

    2016-01-01

    Nonlinear plant-scale interactions controlling the soil-water balance are generally not valid at larger spatial scales due to spatial heterogeneity in rainfall and vegetation type. The relationships between spatially averaged variables are hysteretic even when unique relationships are imposed at the plant scale. The characteristics of these hysteretic relationships depend on the size of the averaging area and the spatial properties of the soil, vegetation, and rainfall. We upscale the plant-scale relationships to the scale of a regional land-surface model based on simulation data obtained through explicit representation of spatial heterogeneity in rainfall and vegetation type. The proposed upscaled function improves predictions of spatially averaged soil moisture and evapotranspiration relative to the effective-parameter approach for a water-limited Texas shrubland. The degree of improvement is a function of the scales of heterogeneity and the size of the averaging area. We also find that single-valued functi...

  17. On the delineation of tropical vegetation types with an emphasis on forest/savanna transitions

    NARCIS (Netherlands)

    Torello-Raventos, M.; Feldpausch, T.R.; Veenendaal, E.M.; Sykora, K.V.

    2013-01-01

    Background: There is no generally agreed classification scheme for the many different vegetation formation types occurring in the tropics. This hinders cross-continental comparisons and causes confusion as words, such as ‘forest’ and ‘savanna’ have different meanings to different people. Tropical ve

  18. Mapping Arctic Plant Functional Type Distributions in the Barrow Environmental Observatory Using WorldView-2 and LiDAR Datasets

    Directory of Open Access Journals (Sweden)

    Zachary Langford

    2016-09-01

    Full Text Available Multi-scale modeling of Arctic tundra vegetation requires characterization of the heterogeneous tundra landscape, which includes representation of distinct plant functional types (PFTs. We combined high-resolution multi-spectral remote sensing imagery from the WorldView-2 satellite with light detecting and ranging (LiDAR-derived digital elevation models (DEM to characterize the tundra landscape in and around the Barrow Environmental Observatory (BEO, a 3021-hectare research reserve located at the northern edge of the Alaskan Arctic Coastal Plain. Vegetation surveys were conducted during the growing season (June–August of 2012 from 48 1 m × 1 m plots in the study region for estimating the percent cover of PFTs (i.e., sedges, grasses, forbs, shrubs, lichens and mosses. Statistical relationships were developed between spectral and topographic remote sensing characteristics and PFT fractions at the vegetation plots from field surveys. These derived relationships were employed to statistically upscale PFT fractions for our study region of 586 hectares at 0.25-m resolution around the sampling areas within the BEO, which was bounded by the LiDAR footprint. We employed an unsupervised clustering for stratification of this polygonal tundra landscape and used the clusters for segregating the field data for our upscaling algorithm over our study region, which was an inverse distance weighted (IDW interpolation. We describe two versions of PFT distribution maps upscaled by IDW from WorldView-2 imagery and LiDAR: (1 a version computed from a single image in the middle of the growing season; and (2 a version computed from multiple images through the growing season. This approach allowed us to quantify the value of phenology for improving PFT distribution estimates. We also evaluated the representativeness of the field surveys by measuring the Euclidean distance between every pixel. This guided the ground-truthing campaign in late July of 2014 for

  19. [Influence of three types of riparian vegetation on fluvial erosion control in Pantanos de Centla, Mexico].

    Science.gov (United States)

    Sepúlveda-Lozada, Alejandra; Geissen, Violette; Ochoa-Gaona, Susana; Jarquín-Sánchez, Aarón; de la Cruz, Simón Hernández; Capetillo, Edward; Zamora-Cornelio, Luis Felipe

    2009-12-01

    Wetlands constitute very important ecological areas. The aim of this study was to quantify the soil losses due to fluvial erosion from 2006 to 2008 in two riverbanks under three types of vegetal coverage dominated by Haematoxylum campechianum, Dalbergia brownei and Brachiaria mutica, in the Pantanos de Centla Biosphere Reserve, SE Mexico. The relationship between the texture, organic matter and pH of soils and soil losses was evaluated. We used erosion sticks to estimate soil losses in 18 plots (three plots per type, three vegetation types, two riverbanks). Soil loss decreased in this order: H. campechianum>B. mutica>D. brownei indicating that D. brownei scrubland has the most potential to retain soil. The higher erosive impact within H. campechianum sites can be related with the low density of these trees in the study areas, as well as the lack of association with other types of vegetation that could reinforce the rooting of the soil profile. Furthermore, soil losses in H. campechianum sites were dependent on soil texture. The soils under this type of vegetal coverage were mainly sandy, which are more vulnerable to the erosive action in comparison with fine textured soils or soils with higher clay content, like the ones found in D. brownei and B. mutica sites. Soil losses of 100 % in the second year (B. mutica plots) can be attributed to the distribution of roots in the upper soil layer and also to livestock management along riverbanks. This study recognizes the importance of D. brownei scrublands in riverbank soil retention. Nevertheless it is necessary to consider the role of an entire vegetal community in future research.

  20. An approach for detecting five typical vegetation types on the Chinese Loess Plateau using Landsat TM data.

    Science.gov (United States)

    Wang, Zhi-Jie; Jiao, Ju-Ying; Lei, Bo; Su, Yuan

    2015-09-01

    Remote sensing can provide large-scale spatial data for the detection of vegetation types. In this study, two shortwave infrared spectral bands (TM5 and TM7) and one visible spectral band (TM3) of Landsat 5 TM data were used to detect five typical vegetation types (communities dominated by Bothriochloa ischaemum, Artemisia gmelinii, Hippophae rhamnoides, Robinia pseudoacacia, and Quercus liaotungensis) using 270 field survey data in the Yanhe watershed on the Loess Plateau. The relationships between 200 field data points and their corresponding radiance reflectance were analyzed, and the equation termed the vegetation type index (VTI) was generated. The VTI values of five vegetation types were calculated, and the accuracy was tested using the remaining 70 field data points. The applicability of VTI was also tested by the distribution of vegetation type of two small watersheds in the Yanhe watershed and field sample data collected from other regions (Ziwuling Region, Huangling County, and Luochuan County) on the Loess Plateau. The results showed that the VTI can effectively detect the five vegetation types with an average accuracy exceeding 80 % and a representativeness above 85 %. As a new approach for monitoring vegetation types using remote sensing at a larger regional scale, VTI can play an important role in the assessment of vegetation restoration and in the investigation of the spatial distribution and community diversity of vegetation on the Loess Plateau.

  1. A quantitative assessment of the vegetation types on the island of St. Eustatius, Dutch Caribbean

    Directory of Open Access Journals (Sweden)

    Tinde van Andel

    2016-07-01

    Full Text Available Caribbean dry forests are among the most endangered tropical ecosystems on earth. Several studies exist on their floristic composition and their recovery after natural or man-made disturbances, but little is known on the small Dutch Caribbean islands. In this study, we present quantitative data on plant species richness and abundance on St. Eustatius, one of the smallest islands of the Lesser Antilles. We collected and identified trees, shrubs, lianas and herbs in 11 plots of 25 x 25 m in different vegetation types. We compared their floristic composition and structure to vegetation surveys from roughly the same locations in the 1990s and 1950s. We found substantial differences among our 11 plots: vegetation types varied from evergreen forests to deciduous shrubland and open woodland. The number of tree species ≥10 cm DBH ranged between one and 17, and their density between three and 82 per plot. In spite that all plots were subject to grazing by free roaming cattle, canopy height and floristic diversity have increased in the last decades. Invasive species are present in the open vegetation types, but not under (partly closed canopy. Comparison with the earlier surveys showed that the decline of agriculture and conservation efforts resulted in the regeneration of dry forests between the 1950s and 2015. This process has also been reported from nearby islands and offers good opportunities for the future conservation of Caribbean dry forests.

  2. Photosynthetic Characterization of Plant Functional Types from Coastal Tundra to Improve Representation of the Arctic in Earth System Models

    Science.gov (United States)

    Rogers, A.; Xu, C.; McDowell, N. G.; Sloan, V. L.; Norby, R. J.

    2012-12-01

    The primary goal of Earth System Models (ESMs) is to improve understanding and projection of future global change. In order to do this they must accurately represent the carbon fluxes associated with the terrestrial carbon cycle. Photosynthetic CO2 uptake is well described by the Farquhar, von Caemmerer and Berry model of photosynthesis, and most ESMs use a derivation of this model. One of the key parameters required by the Farquhar, von Caemmerer and Berry model is an estimate of the maximum rate of carboxylation by the enzyme Rubisco (Vc,max). In ESMs the parameter Vc,max is usually fixed for a given plant functional type (PFT) and often estimated from the empirical relationship between leaf N content and Vc,max. However, uncertainty in the estimation of Vc,max has been shown to account for significant variation in model estimation of gross primary production, particularly in the Arctic. As part of a new multidisciplinary project to improve the representation of the Arctic in ESMs (Next Generation Ecosystem Experiments - Arctic) we have begun to characterize photosynthetic parameters and N acquisition in the key Arctic PFTs. We measured the response of photosynthesis (A) to internal CO2 concentration (ci) in situ in two sedges (Carex aquatilis, Eriophorum angustifolium), a grass (Dupontia fisheri) and a forb (Petasites frigidus) growing on the Barrow Environmental Observatory, Barrow, AK. The values of Vc,max (normalized to 25oC) currently used to represent Arctic PFTs in ESMs are approximately half of the values we measured in these species in July, 2012, on the coastal tundra in Barrow. We hypothesize that these plants have a greater fraction of leaf N invested in Rubisco (FLNR) than is assumed by the models. The parameter Vc,max is used directly as a driver for respiration in some ESMs, and in other ESMs Vc,max is linked to leaf N content and N acquisition through FLNR. Therefore, these results have implications for ESMs beyond photosynthesis, and suggest that

  3. [CHARACTERISTICS OF COMBINED ANESTHESIA WITH EPIDURAL COMPONENTE DEPENDING ON VEGETATIVE NERVOUS SYSTEM TYPE].

    Science.gov (United States)

    Hasanov, F J; Aslanov, A A; Muradov, N F; Namazova, K N

    2016-01-01

    The research objective was to study the characteristics of combined anesthesia with epidural componente (CAEC) depending on vegetative nervous system type (VNS) in patients who underwent large scale traumatic surgical operations on abdominal cavity organs. The scientific research was conducted in Anaesthesiology--Reanimation Department of the Scientific Surgical Centre named after acad. MA. Topchubashev, the Ministry of Health of the Azerbaijan Republic. The research objects were 69 patients who underwent operations in conditions of CAEC due to different serious surgical pathologies of abdominal cavity organs. VNS type was identified based on electroencephalogram, Cerdo Vegetative Index (CVI), Hildebrandt coefficient (HC) and single neurophysiological tests. The patients were divided into three groups depending on VNS type: I--normotonics--17 patients (24.7%), II--sympathatonics--25 patients (36.2%), and III--vagotonics--27 patients (39.1%). Blood adrenocorticotropic hormone (ACTH) and cortisol concentration were studied in 3 stages: I -preoperative, II--operation traumatic stage, III--the 1st postoperative days. The other indicators (heart rate, systolic blood pressure--SBP, dyastolic blood pressure--DBR average blood pressure--BP ave., pulse oximetry SpO₂, ECG, gases in blood and acid-base balance, electrolytes, blood glucose level, myocardium oxygen demand--MOD) were registered after 20 minutes and the 2nd day after operation besides the above stages. The research results indicated that it is possible to define the vegetative nervous system type superiority based on complex of single tests data, EEG, ECG, Cerdo Vegetative Index, Hildebrandt coefficient. CAEC can be considered optimun alternative of general anesthesia ensuring neurohumoral and hemodynamic stability in large scale, traumatic operations on abdominal cavity organs. Clinical course of CAEC is characterized by firmer hemodynamic and humoral stability in patients with functional balance of

  4. Impact of climate and vegetation type on evapotranspiration from green roofs

    Science.gov (United States)

    Sia, M. E.; Robinson, C. E.; O'Carroll, D. M.; Voogt, J. A.; Smart, C. C.; Way, D. A.

    2015-12-01

    Green roofs are an increasingly popular low impact development tool used to mitigate the adverse effects of urbanization and the loss of vegetated spaces. The benefits of green roofs include reducing stormwater volume and peak flows, reducing building energy loads, and mitigating the urban heat island effect. Evapotranspiration (ET) is a key process fundamental to hydrologic and thermal performance of green roofs. For example, ET governs the water storage volume available in the soil medium and thus the ability of the green roof to retain and attenuate stormwater. Green roof design considerations such as soil medium depth and plant type impact ET rates. Additionally, climate has a strong impact on ET rates. To date, the influence between climate and green roof design factors (e.g. vegetation type and soil medium depth) on ET rates have not been well quantified. We performed a field study to evaluate the impact of climate, vegetation type, and soil medium depth on ET rates from extensive modular green roofs over prolonged drying periods. Three Canadian cities with distinct climates were chosen as field sites: London, ON, Calgary, AB, and Halifax, NS. At each site, daily module weights were recorded from May to August in 2013 and 2014 for approximately 40 green roof modules. These modules were divided into four vegetation treatments (three single species and one mixed species), and each treatment was divided into two groups of soil medium depth (10 cm or 15 cm). Daily ET rates and seasonal moisture loss were calculated and compared for the modules to determine which treatment provided the highest ET rates. The root depth profile, leaf area index, and stomatal resistance were also measured. On average, daily ET rates among the vegetation treatments did not vary greatly, however, observations on plant survival indicate which plant types are best suited for each site. In all three sites, mixed species in 15 cm of soil medium had higher seasonal moisture loss compared to

  5. Vegetable but not fruit consumption reduces the risk of type 2 diabetes in Chinese women.

    Science.gov (United States)

    Villegas, Raquel; Shu, Xiao Ou; Gao, Yu-Tang; Yang, Gong; Elasy, Tom; Li, Honglan; Zheng, Wei

    2008-03-01

    We examined associations between fruit and vegetable intake and the incidence of type 2 diabetes (T2D) in a population-based prospective study of 64,191 women with no history of T2D or other chronic diseases at study recruitment and with valid dietary information. Dietary intake was assessed by in-person interviews using a validated FFQ. During 297,755 person-years of follow-up, 1608 new cases of T2D were documented. We used a Cox regression model to evaluate the association of fruit and vegetable intake (g/d) with the risk of T2D. Quintiles of vegetable intake and T2D were inversely associated. The relative risk for T2D for the upper quintile relative to the lower quintile of vegetable intake was 0.72 (95%CI: 0.61-0.85; P Fruit intake was not associated with the incidence of diabetes in this population. Our data suggest that vegetable consumption may protect against the development of T2D.

  6. Assessing climate refugia from a terrestrial vegetation vulnerability assessment for 29 types in California.

    Science.gov (United States)

    Thorne, J. H.; Bjorkman, J.; Boynton, R.; Stewart, J.; Holguin, A.; Schwartz, M.; Albright, W.

    2015-12-01

    We assessed the climate vulnerability of 29 terrestrial macrogroup vegetation types in the National Vegetation Classification Scheme covering 99% of California. Using a 2015 landcover map, we defined current and future climate exposure of each type by assessing conditions at all known locations. This approach identifies both areas of expected high stress and of climate refugia. Species distribution models of the vegetation types proved to over-predict the extent of occupied lands, compared to their mapped extents. Trait based components of the vulnerability assessment were far less influential on level of vulnerability than climate projection. Various cutoffs can be selected to describe refugia. Here we classed refugia as the 20% of climate conditions most frequently occupied by a type. Under CNRM CM5 RCP 4.5, of 70,143 km2 that are the most climate-insulated locations, 46,420 km2 move to higher levels of climate exposure. At the other extreme of climate projections tested, MIROC ESM RCP 8.5, 59,137 km2 are lost. Four macrogroups lose their refugia under CNRM 4.5: Pacific Northwest Conifer Forests, Mountain Riparian Scrub and Wet Meadow, Salt Marsh, and Great Basin Upland Scrub. Under MIROC 8.5 and additional 8 macrogroups lose the most commonly experienced climate: Subalpine Aspen Forests & Pine Woodlands, Non-Native Forest and Woodlands, North Coast Deciduous Scrub and Terrace Prairie, Coastal Dune and Bluff Scrub, Freshwater Marsh, Wet Mountain Meadow, Big Sagebrush Scrub, and Alpine Vegetation. These results raise interesting questions regarding the definition of refugia. We review the results and ask how appropriate they are for different ecosystem types.

  7. Effects of neighboring vascular plants on the abundance of bryophytes in different vegetation types

    Science.gov (United States)

    Jägerbrand, Annika K.; Kudo, Gaku; Alatalo, Juha M.; Molau, Ulf

    2012-07-01

    Due to the climate change, vegetation of tundra ecosystems is predicted to shift toward shrub and tree dominance, and this change may influence bryophytes. To estimate how changes in growing environment and the dominance of vascular plants influence bryophyte abundance, we compared the relationship of occurrence of bryophytes among other plant types in a five-year experiment of warming (T), fertilization (F) and T + F in two vegetation types, heath and meadow, in a subarctic-alpine ecosystem. We compared individual leaf area among shrub species to confirm that deciduous shrubs might cause severe shading effect. Effects of neighboring functional types on the performance of Hylocomium splendens was also analyzed. Results show that F and T + F treatments significantly influenced bryophyte abundance negatively. Under natural conditions, bryophytes in the heath site were negatively related to the abundance of shrubs and lichens and the relationship between lichens and bryophytes strengthened after the experimental period. After five years of experimental treatments in the meadow, a positive abundance relationship emerged between bryophytes and deciduous shrubs, evergreen shrubs and forbs. This relationship was not found in the heath site. Our study therefore shows that the abundance relationships between bryophytes and plants in two vegetation types within the same area can be different. Deciduous shrubs had larger leaf area than evergreen shrubs but did not show any shading effect on H. splendens.

  8. Long-Term Arctic Peatland Dynamics, Vegetation and Climate History of the Pur-Taz Region, Western Siberia

    Science.gov (United States)

    Peteet, Dorothy; Andreev, Andrei; Bardeen, William; Mistretta, Francesca

    1998-01-01

    Stratigraphic analyses of peat composition, LOI, pollen, spores, macrofossils, charcoal, and AMS ages are used to reconstruct the peatland, vegetation and climatic dynamics in the Pur-Taz region of western Siberia over 5000 years (9300 - 4500 BP). Section stratigraphy shows many changes from shallow lake sediment to different combinations of forested or open sedge, moss, and Equisetum fen and peatland environments. Macrofossil and pollen data indicate that Larix sibirica and Betula pubescens trees were first to arrive, followed by Picea obovata. The dominance of Picea macrofossils 6000-5000 BP in the Pur-Taz peatland along with regional Picea pollen maxima indicate warmer conditions and movement of the spruce treeline northward at this time. The decline of pollen and macrofossils from all of these tree species in uppermost peats suggests a change in the environment less favorable for their growth, perhaps cooler temperatures and/or less moisture. Of major significance is the evidence for old ages of the uppermost peats in this area of Siberia, suggesting a real lack of peat accumulation in recent millennia or recent oxidation of uppermost peat.

  9. Effect of vegetative filter strips on herbicide runoff under various types of rainfall.

    Science.gov (United States)

    Otto, Stefan; Cardinali, Alessandra; Marotta, Ester; Paradisi, Cristina; Zanin, Giuseppe

    2012-06-01

    Narrow vegetative filter strips proved to effectively reduce herbicide runoff from cultivated fields mainly due to the ability of vegetation to delay surface runoff, promote infiltration and adsorb herbicides. A field trial was conducted from 2007 to 2009 in north-east Italy in order to evaluate the effectiveness of various types of vegetative filter strips to reduce spring-summer runoff of the herbicides mesotrione, metolachlor and terbuthylazine, widely used in maize, and to evaluate the effect of the rainfall characteristics on the runoff volume and concentration. Results show that without vegetative filter strip the herbicide load that reaches the surface water is about 5-6 g ha(-1)year(-1) for metolachlor and terbuthylazine (i.e. 0.5-0.9% of the applied rate), confirming that runoff from flat fields as in the Po Valley can have a minor effect on the water quality, and that most of the risk is posed by a few, or even just one extreme rainfall event with a return period of about 25-27 years, causing runoff with a maximum concentration of 64-77 μg L(-1). Mesotrione instead showed rapid soil disappearance and was observed at a concentration of 1.0-3.8 μg L(-1) only after one extreme (artificial) rainfall. Vegetative filter strips of any type are generally effective and can reduce herbicide runoff by 80-88%. Their effectiveness is steady even under severe rainfall conditions, and this supports their implementation in an environmental regulatory scheme at a catchment or regional scale.

  10. An integrated probabilistic assessment to analyse stochasticity of soil erosion in different restoration vegetation types

    Science.gov (United States)

    Zhou, Ji; Fu, Bojie; Gao, Guangyao; Lü, Yihe; Wang, Shuai

    2017-03-01

    The stochasticity of soil erosion reflects the variability of soil hydrological response to precipitation in a complex environment. Assessing this stochasticity is important for the conservation of soil and water resources; however, the stochasticity of erosion event in restoration vegetation types in water-limited environment has been little investigated. In this study, we constructed an event-driven framework to quantify the stochasticity of runoff and sediment generation in three typical restoration vegetation types (Armeniaca sibirica (T1), Spiraea pubescens (T2) and Artemisia copria (T3)) in closed runoff plots over five rainy seasons in the Loess Plateau of China. The results indicate that, under the same rainfall condition, the average probabilities of runoff and sediment in T1 (3.8 and 1.6 %) and T3 (5.6 and 4.4 %) were lowest and highest, respectively. The binomial and Poisson probabilistic model are two effective ways to simulate the frequency distributions of times of erosion events occurring in all restoration vegetation types. The Bayes model indicated that relatively longer-duration and stronger-intensity rainfall events respectively become the main probabilistic contributors to the stochasticity of an erosion event occurring in T1 and T3. Logistic regression modelling highlighted that the higher-grade rainfall intensity and canopy structure were the two most important factors to respectively improve and restrain the probability of stochastic erosion generation in all restoration vegetation types. The Bayes, binomial, Poisson and logistic regression models constituted an integrated probabilistic assessment to systematically simulate and evaluate soil erosion stochasticity. This should prove to be an innovative and important complement in understanding soil erosion from the stochasticity viewpoint, and also provide an alternative to assess the efficacy of ecological restoration in conserving soil and water resources in a semi-arid environment.

  11. Effects of temperature seasonality on tundra vegetation productivity using a daily vegetation dynamics model

    Science.gov (United States)

    Epstein, H. E.; Erler, A.; Frazier, J.; Bhatt, U. S.

    2011-12-01

    Changes in the seasonality of air temperature will elicit interacting effects on the dynamics of snow cover, nutrient availability, vegetation growth, and other ecosystem properties and processes in arctic tundra. Simulation models often do not have the fine temporal resolution necessary to develop theory and propose hypotheses for the effects of daily and weekly timescale changes on ecosystem dynamics. We therefore developed a daily version of an arctic tundra vegetation dynamics model (ArcVeg) to simulate how changes in the seasonality of air temperatures influences the dynamics of vegetation growth and carbon sequestration across regions of arctic tundra. High temporal-resolution air and soil temperature data collected from field sites across the five arctic tundra bioclimate subzones were used to develop a daily weather generator operable for sites throughout the arctic tundra. Empirical relationships between temperature and soil nitrogen were used to generate daily dynamics of soil nitrogen availability, which drive the daily uptake of nitrogen and growth among twelve tundra plant functional types. Seasonal dynamics of the remotely sensed normalized difference vegetation index (NDVI) and remotely sensed land surface temperature from the Advanced Very High Resolution Radiometer (AVHRR) GIMMS 3g dataset were used to investigate constraints on the start of the growing season, although there was no indication of any spatially consistent temperature or day-length controls on greening onset. Because of the exponential nature of the relationship between soil temperature and nitrogen mineralization, temperature changes during the peak of the growing season had greater effects on vegetation productivity than changes earlier in the growing season. However, early season changes in temperature had a greater effect on the relative productivities of different plant functional types, with potential influences on species composition.

  12. Characteristic of Soil Hydro-Physical Properties and Water Dynamics under Different Vegetation Restoration Types

    Institute of Scientific and Technical Information of China (English)

    MA Zelong; GONG Yuanbo; HU Tingxing

    2006-01-01

    By combining the observation of the soil profile at field and the chemical and physical analysis in laboratory, a study on the hydro-physical properties of soil in six different vegetation types and the dynamics of water content after rain was conducted in Wanchanggou, Guangyuan City to find out the vegetation types with effective water-conservation functions in order to serve the ecological restoration in the low hill heavy rain area upper the Jialing River. Results showed that:the hydro-physical properties of soil in the mixed Alnus cremastogyne and Cupressua Leyland forest (AcCl) were best. But in the depth of 0-20 cm. The properties of soil in the abandoned cropland (Fm) was better than that in the AcCl. The soil bulk densities varied significantly between the layers of 0-20 cm and 20-40 cm in all the six vegetation types except that in the Robinia pseudoacacia shrub forest (RpⅡ), and the changes of the maximum and the capillary moisture capacity between layers were significant only in the Fm and in the AcCl. Of these stands, the AcCl had the shortest water-absorbing period and the strongest moisture changes in the upper layer (0-15 cm). In the same stand, the deeper the soil layer, the slighter the soil moisture varied, and the longer the soil moisture accumulating process lasted.

  13. Effect of non-crop vegetation types on conservation biological control of pests in olive groves.

    Science.gov (United States)

    Paredes, Daniel; Cayuela, Luis; Gurr, Geoff M; Campos, Mercedes

    2013-01-01

    Conservation biological control (CBC) is an environmentally sound potential alternative to the use of chemical insecticides. It involves modifications of the environment to promote natural enemy activity on pests. Despite many CBC studies increasing abundance of natural enemies, there are far fewer demonstrations of reduced pest density and very little work has been conducted in olive crops. In this study we investigated the effects of four forms of non-crop vegetation on the abundance of two important pests: the olive psyllid (Euphyllura olivina) and the olive moth (Prays oleae). Areas of herbaceous vegetation and areas of woody vegetation near olive crops, and smaller patches of woody vegetation within olive groves, decreased pest abundance in the crop. Inter-row ground covers that are known to increase the abundance of some predators and parasitoids had no effect on the pests, possibly as a result of lack of synchrony between pests and natural enemies, lack of specificity or intra-guild predation. This study identifies examples of the right types of diversity for use in conservation biological control in olive production systems.

  14. Effect of non-crop vegetation types on conservation biological control of pests in olive groves

    Directory of Open Access Journals (Sweden)

    Daniel Paredes

    2013-07-01

    Full Text Available Conservation biological control (CBC is an environmentally sound potential alternative to the use of chemical insecticides. It involves modifications of the environment to promote natural enemy activity on pests. Despite many CBC studies increasing abundance of natural enemies, there are far fewer demonstrations of reduced pest density and very little work has been conducted in olive crops. In this study we investigated the effects of four forms of non-crop vegetation on the abundance of two important pests: the olive psyllid (Euphyllura olivina and the olive moth (Prays oleae. Areas of herbaceous vegetation and areas of woody vegetation near olive crops, and smaller patches of woody vegetation within olive groves, decreased pest abundance in the crop. Inter-row ground covers that are known to increase the abundance of some predators and parasitoids had no effect on the pests, possibly as a result of lack of synchrony between pests and natural enemies, lack of specificity or intra-guild predation. This study identifies examples of the right types of diversity for use in conservation biological control in olive production systems.

  15. Palaeodistribution modelling of European vegetation types at the Last Glacial Maximum using modern analogues from Siberia: Prospects and limitations

    Science.gov (United States)

    Janská, Veronika; Jiménez-Alfaro, Borja; Chytrý, Milan; Divíšek, Jan; Anenkhonov, Oleg; Korolyuk, Andrey; Lashchinskyi, Nikolai; Culek, Martin

    2017-03-01

    We modelled the European distribution of vegetation types at the Last Glacial Maximum (LGM) using present-day data from Siberia, a region hypothesized to be a modern analogue of European glacial climate. Distribution models were calibrated with current climate using 6274 vegetation-plot records surveyed in Siberia. Out of 22 initially used vegetation types, good or moderately good models in terms of statistical validation and expert-based evaluation were computed for 18 types, which were then projected to European climate at the LGM. The resulting distributions were generally consistent with reconstructions based on pollen records and dynamic vegetation models. Spatial predictions were most reliable for steppe, forest-steppe, taiga, tundra, fens and bogs in eastern and central Europe, which had LGM climate more similar to present-day Siberia. The models for western and southern Europe, regions with a lower degree of climatic analogy, were only reliable for mires and steppe vegetation, respectively. Modelling LGM vegetation types for the wetter and warmer regions of Europe would therefore require gathering calibration data from outside Siberia. Our approach adds value to the reconstruction of vegetation at the LGM, which is limited by scarcity of pollen and macrofossil data, suggesting where specific habitats could have occurred. Despite the uncertainties of climatic extrapolations and the difficulty of validating the projections for vegetation types, the integration of palaeodistribution modelling with other approaches has a great potential for improving our understanding of biodiversity patterns during the LGM.

  16. Dynamics of Aboveground Phytomass of the Circumpolar Arctic Tundra During the Past Three Decades

    Science.gov (United States)

    Epstein, Howard E.; Raynolds, Martha K.; Walker, Donald A.; Bhatt, Uma S.; Tucker, Compton J.; Pinzon, Jorge E.

    2012-01-01

    Numerous studies have evaluated the dynamics of Arctic tundra vegetation throughout the past few decades, using remotely sensed proxies of vegetation, such as the normalized difference vegetation index (NDVI). While extremely useful, these coarse-scale satellite-derived measurements give us minimal information with regard to how these changes are being expressed on the ground, in terms of tundra structure and function. In this analysis, we used a strong regression model between NDVI and aboveground tundra phytomass, developed from extensive field-harvested measurements of vegetation biomass, to estimate the biomass dynamics of the circumpolar Arctic tundra over the period of continuous satellite records (1982-2010). We found that the southernmost tundra subzones (C-E) dominate the increases in biomass, ranging from 20 to 26%, although there was a high degree of heterogeneity across regions, floristic provinces, and vegetation types. The estimated increase in carbon of the aboveground live vegetation of 0.40 Pg C over the past three decades is substantial, although quite small relative to anthropogenic C emissions. However, a 19.8% average increase in aboveground biomass has major implications for nearly all aspects of tundra ecosystems including hydrology, active layer depths, permafrost regimes, wildlife and human use of Arctic landscapes. While spatially extensive on-the-ground measurements of tundra biomass were conducted in the development of this analysis, validation is still impossible without more repeated, long-term monitoring of Arctic tundra biomass in the field.

  17. Comparison of satellite imagery and infrared aerial photography as vegetation mapping methods in an arctic study area: Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Hansen, Birger Ulf; Mosbech, Anders

    1994-01-01

    Remote Sensing, vegetation mapping, SPOT, Landsat TM, aerial photography, Jameson Land, East Greenland......Remote Sensing, vegetation mapping, SPOT, Landsat TM, aerial photography, Jameson Land, East Greenland...

  18. Geodynamics, Seismicity, Minerageny and Ecology of Arctic Regions

    Science.gov (United States)

    Kutinov, Y. G.

    The researches of Arctic region is necessary for beginning from delimitation of Arctic. Geographically concept "Arctic" uncertain enough. There is a set of approach to definition of its borders and set the variants of these borders (eternal permafrost, boreal tayga, drifting ice, temperature, etc.). Most correct the point of view of Ecology is realization of Arctic borders on borders of the Arctic geo - depression. Such approach allows to consider in a complex migration of natural substance and polluting substance from orogenes to deep-water hollows of Arctic Ocean. On other hand, it is necessary to take into account natural power flows from zone of Mid-Arctic ridge system at Arctic Ocean to continental land, that is opposition direction process. The certificates of such influence at different levels of Earth's crust already has collected enough (speed of seismic wave on Moho discontinuity; modern vertical movement of Earth's crust; distribution of temperature on depth; structure of basement, etc.). During the last 250 million years the Arctic geo-depression has been developing as an autonomous region with circumpolar zonality, and mass-and-energy transfer in its bowlers as well as shitting of lithospheric plates and expansion of the ocean are caused by rotational forces under conditions of an expanding planet. Four types of geoecological structures have been recorded on the basis of deep structures, position in the over-all structures of regions, place in geological history of its evolution, time of appearance, geodynamic regimes , seismicity, structural-morphological features, specific form of appearance and composition of magmatic and sedimentary formations, compositions of soil, specific metallogenic nature, types of human activity, etc. It is tectonic Segments of Earth, as geoecological global structures; the continental marginal perioceanic zones; the branches of continental marginal perioceanic zones; the mineragenic province. The main criteria of ecological

  19. Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS in the red spectral range

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2007-01-01

    Full Text Available A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm reflectance structures (i.e. "fingerprint" structures of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS, which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms. The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

  20. Screening of heavy metal containing waste types for use as raw material in Arctic clay-based bricks

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Ottosen, Lisbeth M.; Kirkelund, Gunvor Marie

    2016-01-01

    In the vulnerable Arctic environment, the impact of especially hazardous wastes can have severe consequences and the reduction and safe handling of these waste types are therefore an important issue. In this study, two groups of heavy metal containing particulate waste materials, municipal solid...... waste incineration (MSWI) fly and bottom ashes and mine tailings (i.e., residues from the mineral resource industry) from Greenland were screened in order to determine their suitability as secondary resources in clay-based brick production. Small clay discs, containing 20 or 40% of the different...... particulate waste materials, were fired and material properties and heavy metal leaching tests were conducted before and after firing. Remediation techniques (washing in distilled water and electrodialytical treatment) applied to the fly ash reduced leaching before firing. The mine tailings and bottom ash...

  1. Frost flowers on young Arctic sea ice: The climatic, chemical, and microbial significance of an emerging ice type

    DEFF Research Database (Denmark)

    Barber, D.; Ehn, J.; Pucko, M.

    2014-01-01

    Ongoing changes in Arctic sea ice are increasing the spatial and temporal range of young sea ice types over which frost flowers can occur, yet the significance of frost flowers to ocean-sea ice-atmosphere exchange processes remains poorly understood. Frost flowers form when moisture from seawater...... formed. The new ice and frost flowers dramatically changed the radiative and thermal environment. The frost flowers were about 5°C colder than the brine surface, with an approximately linear temperature gradient from their base to their upper tips. Salinity and δ18O values indicated that frost flowers...... of CO2 at the brine-wetted sea ice surface, in line with expectations from the brine chemistry. Bacteria concentrations generally increased with salinity in frost flowers and the surface slush layer. Bacterial densities and taxa indicated that a selective process occurred at the ice surface...

  2. Differences between Used and Available Microhabitats and Vegetation Types for Giant Gartersnakes Associated with a Restored Marsh in California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data describe differences in percent cover of microhabitats and vegetation types at giant gartersnake locations and random points paired with giant gartersnake...

  3. Major Vegetation Types of the Soutpansberg Conservancy and the Blouberg Nature Reserve, South Africa

    Directory of Open Access Journals (Sweden)

    Theo H.C. Mostert

    2008-05-01

    Full Text Available The Major Megetation Types (MVT and plant communities of the Soutpansberg Centre of Endemism are described in detail, with special reference to the Soutpansberg Conservancy and the Blouberg Nature Reserve. Phytosociological data from 442 sample plots were ordinated using a DEtrended CORrespondence ANAlysis (DECORANA and classified using TWo-Way INdicator SPecies ANalysis (TWINSPAN. The resulting classification was further refined with table-sorting procedures based on the Braun–Blanquet floristic–sociological approach of vegetation classification using MEGATAB. Eight MVT’s were identified and described as Eragrostis lehmanniana var. lehmanniana–Sclerocarya birrea subsp. caffra Blouberg Northern Plains Bushveld, Euclea divinorum–Acacia tortilis Blouberg Southern Plains Bushveld, Englerophytum magalismontanum–Combretum molle Blouberg Mountain Bushveld, Adansonia digitata–Acacia nigrescens Soutpansberg Arid Northern Bushveld, Catha edulis–Flueggia virosa Soutpansberg Moist Mountain Thickets, Diplorhynchus condylocarpon–Burkea africana Soutpansberg Leached Sandveld, Rhus rigida var. rigida–Rhus magalismontanum subsp. coddii Soutpansberg Mistbelt Vegetation and Xymalos monospora–Rhus chirendensis Soutpansberg Forest Vegetation.

  4. Wood-inhabiting fungi in southern Italy forest stands: morphogroups, vegetation types and decay classes.

    Science.gov (United States)

    Granito, Vito Mario; Lunghini, Dario; Maggi, Oriana; Persiani, Anna Maria

    2015-01-01

    The authors conducted an ecological study of forests subjected to varying management. The aim of the study was to extend and integrate, within a multivariate context, knowledge of how saproxylic fungal communities behave along altitudinal/vegetational gradients in response to the varying features and quality of coarse woody debris (CWD). The intra-annual seasonal monitoring of saproxylic fungi, based on sporocarp inventories, was used to investigate saproxylic fungi in relation to vegetation types and management categories. We analyzed fungal species occurrence, recorded according to the presence/absence and frequency of sporocarps, on the basis of the harvest season, of coarse woody debris decay classes as well as other environmental and ecological variables. Two-way cluster analysis, DCA and Spearman's rank correlations, for indirect gradient analysis, were performed to identify any patterns of seasonality and decay. Most of the species were found on CWD in an intermediate decay stage. The first DCA axis revealed the vegetational/microclimate gradient as the main driver of fungal community composition, while the second axis corresponded to a strong gradient of CWD decay classes.

  5. Abundance and Dynamics of Soil Labile Carbon Pools Under Different Types of Forest Vegetation

    Institute of Scientific and Technical Information of China (English)

    JIANG Pei-Kun; XU Qiu-Fang

    2006-01-01

    Soil organic matter (SOM) in forest ecosystems is not only important to global carbon (C) storage but also to sustainable management of forestland with vegetation types, being a critical factor in controlling the quantity and dynamics of SOM. In this field experiment soil plots with three replicates were selected from three forest vegetation types: broadleaf,Masson pine (Pinus massoniana Lamb.), and Chinese fir (Cunninghamia lanceolata Hook.). Soil total organic C (TOC),two easily oxidizable C levels (EOC1 and EOC2, which were oxidized by 66.7 mmol L-1 K2Cr2O7 at 130-140 ℃ and333 mmol L-1 KMnO4 at 25 ℃, respectively), microbial biomass C (MBC), and water-soluble organic C (WSOC)were analyzed for soil samples. Soil under the broadleaf forest stored significantly higher TOC (P ≤ 0.05). Because of its significantly larger total soil C storage, the soil under the broadleaf forest usually had significantly higher levels (P ≤ 0.05)of the different labile organic carbons, EOC1, EOC2, MBC, and WSOC; but when calculated as a percentage of TOC each labile C fraction of the broadleaf forest was significantly lower (P ≤ 0.05) than one of the other two forests. Under all the three vegetation types temperature as well as quality and season of litter input generally affected the dynamics of different organic C fractions in soils, with EOC1, EOC2, and MBC increasing closely following increase in temperature,whereas WSOC showed an opposite trend.

  6. Using vegetation cover type to predict and scale peatland methane dynamics.

    Science.gov (United States)

    McArthur, K. J.; McCalley, C. K.; Palace, M. W.; Varner, R. K.; Herrick, C.; DelGreco, J. L.

    2015-12-01

    Permafrost ecosystems contain about 50% of the global soil carbon. As these northern ecosystems experience warmer temperature, permafrost thaws and may result in an increase in atmospheric methane. We examined a thawing and discontinuous permafrost boundary at Stordalen Mire, in Northern Sweden, in an effort to better understand methane emissions. Stable isotope analysis of methane in peatland porewater can give insights into the pathway of methane production. By measuring δ13CH4 we can predict whether a system is dominated by either hydrogenotrophic or acetaclastic methane production. Currently, it is a challenge to scale these isotopic patterns, thus, atmospheric inversion models simply assume that acetoclastic production dominates. We analyzed porewater samples collected across a range of vegetation cover types for δ13CH4 using a QCL (Quantum Cascade Laser Spectrometer) in conjunction with highly accurate GPS (3-10cm) measurements and high-resolution UAV imaging. We found δ13CH4 values ranging from -88‰ to -41‰, with averages based on cover type and other vegetation features showing differences of up to -15‰. We then used a computer neural network to predict cover types across Stordalen Mire from UAV imagery based on field-based plot measurements and training samples.. This prediction map was used to scale methane flux and isotope measurements. Our results suggest that the current values used in atmospheric inversion studies may oversimplify the relationship between plant and microbial communities in complex permafrost landscapes. As we gain a deeper understanding of how vegetation relates to methanogenic communities, understanding the spatial component of ecosystem methane metabolism and distribution will be increasingly valuable.

  7. Types of fruits and vegetables used in commercial baby foods and their contribution to sugar content.

    Science.gov (United States)

    Garcia, Ada Lizbeth; McLean, Kimberley; Wright, Charlotte M

    2016-10-01

    Fruits and vegetables (F&V) are often featured in names of commercial baby foods (CBFs). We aimed to survey all available CBFs in the UK market with F&V included in the food name in order to describe the amount and types of F&V used in CBF and their contribution to total sugar content. Food labels were used to identify F&V and total sugar content. Fruits were more common than vegetables in names of the 329 CBFs identified. The six most common F&V in the names were all relatively sweet: apple, banana, tomato, mango, carrot and sweet potato. The percentage of F&V in the foods ranged from a median of 94% for sweet-spoonable to 13% for dry-savoury products. Fruit content of sweet foods (n = 177) was higher than vegetable content of savoury foods (n = 152) with a median (IQR) of 64.0 g/100 g (33.0-100.0) vs. 46.0 g/100 g (33-56.7). Fruit juice was added to 18% of products. The proportion of F&V in CBF correlated significantly with sugar content for all the food types except dry-savoury food (sweet-spoonable r = 0.24, P = 0.006; savoury-spoonable r = 0.65, P < 0.001; sweet-dry r = 0.81, P < 0.001; savoury-dry r = 0.51, P = 0.06) and explained up to two-thirds of the variation in sugar content. The F&V content of CBFs mainly consists of fruits and relatively sweet vegetables which are unlikely to encourage preferences for bitter-tasting vegetables or other non-sweet foods. F&V contribute significantly to the total sugar content, particularly of savoury foods.

  8. Cloud radiative forcing sensitivity to Arctic synoptic regimes, surface type, cloud phase and cloud properties during the Fall 2014 Arctic Radiation, IceBridge and Sea-Ice Experiment (ARISE)

    Science.gov (United States)

    Segal-Rosenheimer, Michal; Redemann, Jens; Shinozuka, Yohei; Flynn, Connor; LeBanc, Samuel; Schmidt, Sebastian; Song, Shi; Bucholtz, Anthony; Reid, Elizabeth; Anderson, Bruce; Corr, Chelsea; Smith, William L.; Kato, Seiji; Spangenberg, Douglas A.; Hofton, Michelle; Moore, Richard; Winstead, Edward; Thornhill, Lee K.

    2015-04-01

    Surface cloud radiative forcing (CRF) estimates in the Arctic cover a wide range of values when comparing various datasets (e.g. MERRA, CERES), and show high bias when compared to in-situ ground-based flux measurement stations (e.g. in Greenland) [Wenshan and Zender, 2014]. These high variations and biases result from an intricate relationship between the prevailing synoptic regimes, surface types (open ocean versus sea-ice), and cloud properties [e.g. Barton et al., 2012; Bennartz et al., 2013]. To date, analyses are focused on large-scale or inter-annual comparisons [e.g. Barton et al., 2012; Taylor et al., 2014], or on several specific ground-based sites [Shupe et al., 2004; Sedlar et al., 2012]. Nevertheless, smaller scale CRF variations related to the sharp changes in sea-ice cover, cloud type and synoptic regimes in autumn are still not well understood. Here, we are focusing on assessing the CRF sensitivity to a composite variable matrix of atmospheric stability regimes, cloud profiles and properties and surface type changes during the NASA ARISE campaign conducted in the Fall of 2014 during the Arctic sea-ice minimum in the Beaufort Sea. We are interested in answering the following questions: (1) what are the combinations of distinct synoptic regimes, surface types, and cloud properties that result in the lowest or highest simulated CRF values over the Arctic Beaufort Sea during the autumn 2014 sea-ice growth period?, and (2) can we relate these simulated extremes to the observations made during the ARISE campaign? We are using the libRadtran radiative transfer modeling package to calculate the CRF sensitivity matrix, with daily gridded atmospheric profiles input from MERRA re-analysis, cloud fields and properties from CALIPSO, MODIS, AVHRR, daily variations in sea-ice margins from AMSR-2, and complementary airborne measurements collected on the C-130 during the campaign. In performing sensitivity analysis, we examine CRF extremes sorted by atmospheric

  9. Invertebrate availability and vegetation characteristics explain use of nonnesting cover types by mature-forest songbirds during the postfledging period

    Science.gov (United States)

    Streby, Henry M.; Peterson, Sean M.; Andersen, D.E.

    2011-01-01

    Some species of mature-forest-nesting songbirds use regenerating clearcuts and forested wetlands during the postfledging period (between nesting and migration). Relatively dense vegetation structure and abundant food resources in non-mature-forest cover types have been hypothesized to explain this phenomenon. We examined the relative importance of vegetation structure and invertebrate availability on use of nonnesting cover types by adult and hatch-year Ovenbirds (Seiurus aurocapilla) and American Redstarts (Setophaga ruticilla) during the postfledging period of 2009 in northern Minnesota. We used mist nets to sample bird use of forested wetlands and regenerating clearcuts of three age groups: 1-6, 7-12, and 16-19 yr after harvest. We modeled captures of birds using vegetation characteristics and invertebrate availability sampled around nets as explanatory variables. For all birds studied, captures were best explained by food availability and secondarily by vegetation characteristics including litter depth and woody debris for Ovenbirds and canopy height for American Redstarts. Shrub-level invertebrate availability received a cumulative weight of 0.74-0.99 in Akaike's information criterion corrected ranked models for adult and hatch-year birds of both species. Vegetation density and variation in vegetation density explained almost no variation in captures of either species. We conclude that both invertebrate availability and some vegetation characteristics influence use of nonnesting cover types by Ovenbirds and American Redstarts during the postfledging period, but that invertebrate availability is generally the stronger predictor of that use. ?? 2011 Association of Field Ornithologists.

  10. Variations of deep soil moisture under different vegetation types and influencing factors in a watershed of the Loess Plateau, China

    Science.gov (United States)

    Fang, Xuening; Zhao, Wenwu; Wang, Lixin; Feng, Qiang; Ding, Jingyi; Liu, Yuanxin; Zhang, Xiao

    2016-08-01

    Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the variations in deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focus on analyzing the variations and factors that influence the deep soil moisture (DSM) in 80-500 cm soil layers based on a soil moisture survey of the Ansai watershed in Yan'an in Shanxi Province. Our results can be divided into four main findings. (1) At the watershed scale, higher variations in the DSM occurred at 120-140 and 480-500 cm in the vertical direction. At the comparable depths, the variation in the DSM under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The DSM in native vegetation and human-managed vegetation was significantly higher than that in introduced vegetation, and different degrees of soil desiccation occurred under all the introduced vegetation types. Caragana korshinskii and black locust caused the most serious desiccation. (3) Taking the DSM conditions of native vegetation as a reference, the DSM in this watershed could be divided into three layers: (i) a rainfall transpiration layer (80-220 cm); (ii) a transition layer (220-400 cm); and (iii) a stable layer (400-500 cm). (4) The factors influencing DSM at the watershed scale varied with vegetation types. The main local controls of the DSM variations were the soil particle composition and mean annual rainfall; human agricultural management measures can alter the soil bulk density, which contributes to higher DSM in farmland and apple orchards. The plant growth conditions, planting density, and litter water holding capacity of introduced vegetation showed significant relationships with the DSM. The results of this study are of practical significance for vegetation restoration strategies, especially

  11. Effects of Vegetable Oil Type and Lipophilic Emulsifiers on the Induction Period of Fat Crystallization.

    Science.gov (United States)

    Miyagawa, Yayoi; Ogawa, Takenobu; Nakagawa, Kyuya; Adachi, Shuji

    2015-01-01

    The induction period of crystallization, which is defined as the time required for oil to start to crystallize, is useful indicator of the freeze-thaw stability of food emulsions such as mayonnaise. We investigated the induction period of vegetable oils with low melting points, such as rapeseed and soybean oils, which are commonly employed for mayonnaise production. The induction period was measured by monitoring the temperature of a specimen during storage at low temperature. The induction period depended on the type of oil and lipophilic emulsifier, emulsifier concentration, and storage temperature. The effect of the oil type on the induction period depended on the composition of the oil. Differential scanning calorimetry (DSC) analyses of the lipophilic emulsifiers suggested that the melting trend of the emulsifier is strongly related to the induction period.

  12. The effect of vegetation type and fire on permafrost thaw: An empirical test of a process based model

    Science.gov (United States)

    Thierry, Aaron; Estop-Aragones, Cristian; Fisher, James; Hartley, Iain; Murton, Julian; Phoenix, Gareth; Street, Lorna; Williams, Mathew

    2015-04-01

    As conditions become more favourable for plant growth in the high latitudes, most models predict that these areas will take up more carbon during the 21st century. However, vast stores of carbon are frozen in boreal and arctic permafrost, and warming may result in some of this carbon being released to the atmosphere. The recent inclusion of permafrost thaw in large-scale model simulations has suggested that the permafrost feedback could potentially substantially reduce the predicted global net uptake of carbon by terrestrial ecosystems, with major implications for the rate of climate change. However, large uncertainties remain in predicting rates of permafrost thaw and in determining the impacts of thaw in contrasting ecosystems, with many of the key processes missing from carbon-climate models. The role that different plant communities play in insulating soils and protecting permafrost is poorly quantified, with key groups such as mosses absent in many models. But it is thought that they may play a key role in determining permafrost resilience. In order to test the importance of these ecological processes we use a new specially acquired dataset from sites in the Canadian arctic to develop, parameterise and evaluate a detailed process-based model of vegetation-soil-permafrost interactions which includes an insulating moss understory. We tested the sensitivity of modelled active layer depth to a series of factors linked to fire disturbance, which is common in boreal permafrost areas. We show how simulations of active layer depth (ALD) respond to removals of (i) vascular vegetation, (ii) moss cover, and (iii) organic soil layers. We compare model responses to observed patterns from Canada. We also describe the sensitivity of our modelled ALD to changes in temperature and precipitation. We found that four parameters controlled most of the sensitivity in the modelled ALD, linked to conductivity of organic soils and mosses.

  13. Distinguishing Bark Beetle-infested Vegetation by Tree Species Types and Stress Levels using Landsat Data

    Science.gov (United States)

    Sivanpillai, R.; Ewers, B. E.; Speckman, H. N.; Miller, S. N.

    2015-12-01

    In the Western United States, more than 3 million hectares of lodgepole pine forests have been impacted by the Mountain pine beetle outbreak, while another 166,000 hectares of spruce-fir forests have been attacked by Spruce beetle. Following the beetle attack, the trees lose their hydraulic conductivity thus altering their carbon and water fluxes. These trees go through various stages of stress until mortality, described by color changes in their needles prior to losing them. Modeling the impact of these vegetation types require thematically precise land cover data that distinguishes lodgepole pine and spruce-fir forests along with the stage of impact since the ecosystem fluxes are different for these two systems. However, the national and regional-scale land cover datasets derived from remotely sensed data do not have this required thematic precision. We evaluated the feasibility of multispectral data collected by Landsat 8 to distinguish lodgepole pine and spruce fir, and subsequently model the different stages of attack using field data collected in Medicine Bow National Forest (Wyoming, USA). Operational Land Imager, onboard Landsat 8 has more spectral bands and higher radiometric resolution (12 bit) in comparison to sensors onboard earlier Landsat missions which could improve the ability to distinguish these vegetation types and their stress conditions. In addition to these characteristics, its repeat coverage, rigorous radiometric calibration, wide swath width, and no-cost data provide unique advantages to Landsat data for mapping large geographic areas. Initial results from this study highlight the importance of SWIR bands for distinguishing different levels of stress, and the need for ancillary data for distinguishing species types. Insights gained from this study could lead to the generation of land cover maps with higher thematic precision, and improve the ability to model various ecosystem processes as a result of these infestations.

  14. Vegetation types alter soil respiration and its temperature sensitivity at the field scale in an estuary wetland.

    Directory of Open Access Journals (Sweden)

    Guangxuan Han

    Full Text Available Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively. During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m(-2 s(-1, followed by the Suaeda salsa site (0.77 µmol CO2 m(-2 s(-1 and the bare soil site (0.41 µmol CO2 m(-2 s(-1. The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland.

  15. Luxury consumption of soil nutrients: a possible competitive strategy in above-ground and below-ground biomass allocation and root morphology for slow-growing arctic vegetation?

    NARCIS (Netherlands)

    Wijk, van M.T.; Williams, M.; Gough, L.; Hobbie, S.E.; Shaver, G.R.

    2003-01-01

    1 A field-experiment was used to determine how plant species might retain dominance in an arctic ecosystem receiving added nutrients. We both measured and modelled the above-ground and below-ground biomass allocation and root morphology of non-acidic tussock tundra near Toolik Lake, Alaska, after 4

  16. Suitability of the vegetation types in Mexico's Tamaulipas state for the siting of hazardous waste treatment plants.

    Science.gov (United States)

    Cram, Silke; Sommer, Irene; Morales, Luis-Miguel; Oropeza, Oralia; Carmona, Estela; González-Medrano, Francisco

    2006-07-01

    A land suitability study was carried out by applying a multiple-criteria technique to 12 different vegetation types in Mexico's Tamaulipas state to help select potentially suitable sites for hazardous waste treatment plants. Species richness, spatial distribution, and uniqueness were selected as the criteria for estimating a vegetation type's suitability. Using the analytical hierarchy process, we ranked and mapped vegetation types, then compared the results with rankings of the same vegetation types based only on their number of endemic species. The suitabilities of the various vegetation types were ordered in more or less the same way by both methods, except in two cases for which the results were very different. The method proved to be a useful tool despite the availability of only partial (mostly qualitative) information; under such circumstances, expert experience can be incorporated in the evaluation process to a limited degree. The technique described in this paper has a high potential to aid decisions when many opinions and options must be considered simultaneously.

  17. Burn Severities, Fire Intensities, and Impacts to Major Vegetation Types from the Cerro Grande Fire

    Energy Technology Data Exchange (ETDEWEB)

    Balice, Randy G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bennett, Kathryn D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wright, Marjorie A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2004-12-15

    The Cerro Grande Fire resulted in major impacts and changes to the ecosystems that were burned. To partially document these effects, we estimated the acreage of major vegetation types that were burned at selected burn severity levels and fire intensity levels. To accomplish this, we adopted independently developed burn severity and fire intensity maps, in combination with a land cover map developed for habitat management purposes, as a basis for the analysis. To provide a measure of confidence in the acreage estimates, the accuracies of these maps were also assessed. In addition, two other maps of comparable quality were assessed for accuracy: one that was developed for mapping fuel risk and a second map that resulted from a preliminary application of an evolutionary computation software system, called GENIE.

  18. Impacts of grassland types and vegetation cover changes on surface air temperature in the regions of temperate grassland of China

    Science.gov (United States)

    Shen, Xiangjin; Liu, Binhui; Li, Guangdi; Yu, Pujia; Zhou, Daowei

    2016-10-01

    The sensitivity of surface air temperature response to different grassland types and vegetation cover changes in the regions of temperate grassland of China was analyzed by observation minus reanalysis (OMR) method. The basis of the OMR approach is that reanalysis data are insensitive to local surface properties, so the temperature differences between surface observations and reanalysis can be attributed to land effects. Results showed that growing-season air temperature increased by 0.592 °C/decade in the regions of temperate grassland of China, with about 31 % of observed warming associated with the effects of grassland types and vegetation cover changes. For different grassland types, the growing-season OMR trend was the strongest for temperate desert steppe (0.259 °C/decade) and the weakest for temperate meadow (0.114 °C/decade). Our results suggest that the stronger intraseasonal changes of grassland vegetation are present, the more sensitive the OMR trend responds to the intraseasonal vegetation cover changes. In August and September, the OMR of temperate meadow showed a weak cooling trend. For temperate meadow, about 72.2 and 72.6 % of surface cooling were explained by both grassland type and increase of vegetation cover for August and September, respectively. For temperate steppe and temperate desert steppe, due to the limited soil moisture and little evaporative cooling feedback, the vegetation changes have no significant effect on the surface air temperature. These results indicate that the impact of grassland types and vegetation cover changes should be considered when projecting further climate change in the temperate grassland region of China.

  19. ESPC Regional Arctic Prediction System

    Science.gov (United States)

    2014-09-30

    the Navy the capability to conduct short-term (1 week) to extended (2 weeks) coupled weather forecasts for the Arctic region. APPROACH To...sensitivity of the Arctic weather forecast to key numerical parameters; and 5) conduct extensive validation and verification of the coupled system and...SEP 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE ESPC Regional Arctic Prediction System 5a. CONTRACT

  20. Challenges in modelling isoprene and monoterpene emission dynamics of Arctic plants

    DEFF Research Database (Denmark)

    Tang, Jing; Schurgers, Guy; Valolahti, Hanna Maritta;

    2016-01-01

    The Arctic is warming at twice the global average speed, and the warming-induced increases in biogenic volatile organic compounds (BVOCs) emissions from Arctic plants are expected to be drastic. The current global models' estimations of minimal BVOC emissions from the Arctic are based on very few...... Arctic BVOC emissions are (1) correct leaf T estimation, (2) PFT parameterization accounting for plant emission features as well as physiological responses to warming, and (3) representation of long-term vegetation changes in the past and the future....... emissions levelled off during the last few years. At hour-day scale, the WRs seem to be strongly impacted by canopy air T, while at the day-year scale, the WRs are a combined effect of plant functional type (PFT) dynamics and instantaneous BVOC responses to warming. The identified challenges in estimating......The Arctic is warming at twice the global average speed, and the warming-induced increases in biogenic volatile organic compounds (BVOCs) emissions from Arctic plants are expected to be drastic. The current global models' estimations of minimal BVOC emissions from the Arctic are based on very few...

  1. Assessing onset and length of greening period in six vegetation types in Oaxaca, Mexico, using NDVI-precipitation relationships.

    Science.gov (United States)

    Gómez-Mendoza, L; Galicia, L; Cuevas-Fernández, M L; Magaña, V; Gómez, G; Palacio-Prieto, J L

    2008-07-01

    Variations in the normalized vegetation index (NDVI) for the state of Oaxaca, in southern Mexico, were analyzed in terms of precipitation anomalies for the period 1997-2003. Using 10-day averages in NDVI data, obtained from AVHRR satellite information, the response of six types of vegetation to intra-annual and inter-annual fluctuations in precipitation were examined. The onset and temporal evolution of the greening period were studied in terms of precipitation variations through spectral analysis (coherence and phase). The results indicate that extremely dry periods, such as those observed in 1997 and 2001, resulted in low values of NDVI for much of Oaxaca, while good precipitation periods produced a rapid response (20-30 days of delay) from a stressed to a non-stressed condition in most vegetation types. One of these rapid changes occurred during the transition from dry to wet conditions during the summer of 1998. As in many parts of the tropics and subtropics, the NDVI reflects low frequency variations in precipitation on several spatial scales. Even after long dry periods (2001-2002), the various regional vegetation types are capable of recovering when a good rainy season takes place, indicating that vegetation types such as the evergreen forests in the high parts of Oaxaca respond better to rainfall characteristics (timing, amount) than to temperature changes, as is the case in most mid-latitudes. This finding may be relevant to prepare climate change scenarios for forests, where increases in surface temperature and precipitation anomalies are expected.

  2. Ecosystem CO2 production during winter in a Swedish subarctic region: the relative importance of climate and vegetation type

    DEFF Research Database (Denmark)

    Grogan, Paul; Jonasson, Sven Evert

    2006-01-01

    in these predictions, we know relatively little about the plot and landscape-level controls on tundra biogeochemical cycling in wintertime as compared to summertime. We investigated the relative influence of vegetation type and climate on CO2 production rates and total wintertime CO2 release in the Scandinavian...... in northern Sweden. Both climate and vegetation type were strong interactive controls on ecosystem CO2 production rates during winter. Of all variables tested, soil temperature explained by far the largest amount of variation in respiration rates (41-75%). Our results indicate that vegetation type only...... will respond to climate change during winter because they indicate a threshold (~1 m) above which there would be little effect of increased snow accumulation on wintertime biogeochemical cycling....

  3. Effects of Vegetation Type and Management Practice on Soil Respiration of Grassland in Northern Japan

    Directory of Open Access Journals (Sweden)

    Minaco Adachi

    2013-01-01

    Full Text Available Soil respiration rate in two types of grassland dominated with Zoysia japonica and Miscanthus sinensis, respectively, and under two management practices (undisturbed and intentionally burned for the M. sinensis grassland was investigated for understanding the effects of grassland vegetation type and management practices on the relationship between soil temperature and soil respiration in northern Japan. Soil temperatures at depth of 1 cm in the Z. japonica (ZJ and burned M. sinensis (MSb plots had a larger temporal variation than that in the control M. sinensis (MSc plot prior to early July. However, the coefficient of temperature sensitivity ( values, based on soil respiration rates and soil temperatures at 5 cm depth in the ZJ and MSb plots, were 1.3 and 2.9. These rates were lower than that in the MSc plot (4.3, meaning that soil respiration showed lower activity to an increase in soil temperature in the ZJ and MSb plots. In addition, monthly carbon fluxes from soil in these plots were smaller than that in the MSc plot. These results suggested that artificial disturbance would decrease soil microbial or/and plant root respiration, and it would contribute to the plant productivity. Future studies should examine the effects of the intensity and period of management on the soil respiration rate.

  4. Seasonal variations in the biomass, quantity and quality of agar, from the reproductive and vegetative stages of Gracilaria (verrucosa type)

    Energy Technology Data Exchange (ETDEWEB)

    Whyte, J.N.C.; Englar, J.R.; Saunders, R.G.; Lindsay, J.C.

    1981-09-01

    Optimum growth of Gracilaria (verrucosa type) in British Columbia occurred between 5 and 6 meters below mean field level and correlated with solar radiation throughout the season. Vegetative populations declined with a consequent increase in reproductive forms to a maximum in July. Tetrasporophytes dominated the reproductive population and in July attained the greatest seasonal biomass of all forms of the alga. Maximum population and biomass were attained by carposporophytes in July and by male gametophytes one month earlier. An inverse relationship between biomass and yield of agar was apparent only for the vegetative and tetrasporic forms of the alga. Variations in yields, gel strengths, and gelation characteristics of the agars isolated, were demonstrated to be dependent on time of season and life stages of the alga. Ranked in the following decreasing order of merit as a source of agar were the cystocarpic, tetrasporic, vegetative and male gametophytic forms of Gracilaria (verrucosa type).

  5. TYPE OF VEGETATION AND DISTRIBUTION IN XUNHUA COUNTY%循化县植被类型及分布

    Institute of Scientific and Technical Information of China (English)

    袁青杉

    2012-01-01

    The data of remote sense T M image have been used to type of vegetation of Xunhua county , the re- suits showed that there were 5 types of vegetation forest, shrub , grassland, desert and meadow and 20 vegeta- tion groups, It was obvious vegetation perpendicularity distribution.%根据遥感影像TM数据信息及其文献资料,结合野外验证研究循化县植被类型及其分布。结果表明循化县共有森林、灌丛、草原、荒漠、草甸5个植被型组,20个植被群系;并且植被垂直分布明显。

  6. Classification of hepatitis B virus genotype B into 2 major types based on characterization of a novel subgenotype in Arctic indigenous populations.

    Science.gov (United States)

    Sakamoto, Tomoyuki; Tanaka, Yasuhito; Simonetti, Josephine; Osiowy, Carla; Borresen, Malene L; Koch, Anders; Kurbanov, Fuat; Sugiyama, Masaya; Minuk, Gerald Y; McMahon, Brian J; Joh, Takashi; Mizokami, Masashi

    2007-11-15

    Hepatitis B virus genotype B (HBV/B) has been classified into 5 subgenotypes. Except for Bj/B1 in Japan, the subgenotypes (Ba/B2-B5) have undergone recombination with HBV/C in the core promoter/precore/core genomic region. Phylogenetic analyses of complete sequences show that the Arctic strains belong to a novel subgenotype (HBV/B6) without the recombination, analogous to what is seen with Bj/B1. Comparison of 50 HBV/B6 carriers from the Arctic versus 50 Bj and 50 Ba age- and sex-matched carriers from Asia revealed that clinical characteristics of HBV/B6 carriers were similar to those of Bj/B1 carriers in Japan. The results suggest that HBV/B may be classified into nonrecombinant (Bj/B1 and B6) and recombinant (Ba/B2-B5) types.

  7. Effects of different vegetation types on the shear strength of root-permeated soils

    Science.gov (United States)

    Yildiz, Anil; Graf, Frank; Rickli, Christian; Springman, Sarah M.

    2016-04-01

    The effects of vegetation and, in particular, of forests on the stability of slopes are well recognized and have been widely studied in recent decades. However, there is still a lack of understanding of the underlying processes that occur prior to triggering superficial failures in root-permeated soil. Thus, appropriate quantification of the vegetation effects on the shear strength of soil is crucial in order to be able to evaluate the stability of a vegetated slope. Direct shear testing is widely employed to determine the shearing response of root-permeated soil. However, mechanical aspects of direct shear apparatuses may affect the shear strength parameters derived, which often remains unnoticed and hampers direct comparison between different studies. A robust Inclinable Large-scale Direct Shear Apparatus (ILDSA), with dimensions of 500x500x400 mm, was built in order to shear root-permeated soil specimens and to analyse the influence of the machine setup on the results, too. Two different sets of planted specimens were prepared using moraine (SP-SM) from a recent landslide area in Central Switzerland: a first set consisting of Alnus incana, Trifolium pratense, Poa pratensis and a second set, consisting of these three species complemented with Salix appendiculata, Achillea millefolium, Anthyllis vulneraria. Direct shear tests were conducted on specimens planted with the different vegetation types, at a constant rate of horizontal displacement of 1 mm/min up to a maximum horizontal displacement of 190 mm, and under three different applied normal stresses: 6 kPa, 11 kPa and 16 kPa. Artificial rainfall was applied at a constant intensity (100 mm/h) prior to shearing. Tensiometers had been installed close to the shear surface and were monitored continuously to obtain the matric suction during the saturation process. Suctions were reduced as close to 0 kPa as possible, in order to simulate the loss of strength after a heavy period of rainfall. The analyses of the above

  8. Assessment of the transfer of {sup 137}Cs in three types of vegetables consumed in Hong Kong

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K.N.; Mao, S.Y.; Young, E.C.M

    1998-12-01

    A dynamic food chain model has been built for the modeling of the transfer of {sup 137}Cs in three types of vegetables consumed in Hong Kong, namely, white flowering cabbage (Brassica chinensis), head lettuce (Lactuca sativa) and celery (Apium graveolens). Some parameters have been estimated from the experimental data obtained in this work. The experimental data include the transfer factors of {sup 137}Cs from soil to the different vegetable species which are determined through high resolution gamma spectrometry, maximum crop biomasses for the vegetable species, the dry-to-fresh ratios for the vegetable species, the bulk density of soil layers and the average concentration of {sup 137}Cs in air. The derived parameters include the deposition rate and the root uptake rate, information for tillage, the logistic growth model and radionuclide concentrations in vegetables. The dynamic food chain model is solved by the Birchall-James algorithm to give the {sup 137}Cs concentration in subsurface soil, from the 0.1-25 cm soil layer, and the {sup 137}Cs concentration in harvested and unwashed vegetables. As validation of the model and parameters, the concentrations obtained experimentally and from the model are compared and are found to be in good agreement.

  9. Structural complexity and land-surface energy exchange along a gradient from arctic tundra to boreal forest

    Science.gov (United States)

    Thompson, C.; Beringer, J.; Chapin, F. S.; McGuire, A.D.

    2004-01-01

    Question: Current climate changes in the Alaskan Arctic, which are characterized by increases in temperature and length of growing season, could alter vegetation structure, especially through increases in shrub cover or the movement of treeline. These changes in vegetation structure have consequences for the climate system. What is the relationship between structural complexity and partitioning of surface energy along a gradient from tundra through shrub tundra to closed canopy forest? Location: Arctic tundra-boreal forest transition in the Alaskan Arctic. Methods: Along this gradient of increasing canopy complexity, we measured key vegetation characteristics, including community composition, biomass, cover, height, leaf area index and stem area index. We relate these vegetation characteristics to albedo and the partitioning of net radiation into ground, latent, and sensible heating fluxes. Results: Canopy complexity increased along the sequence from tundra to forest due to the addition of new plant functional types. This led to non-linear changes in biomass, cover, and height in the understory. The increased canopy complexity resulted in reduced ground heat fluxes, relatively conserved latent heat fluxes and increased sensible heat fluxes. The localized warming associated with increased sensible heating over more complex canopies may amplify regional warming, causing further vegetation change in the Alaskan Arctic.

  10. Effect of Replacing Pork Fat with Vegetable Oils on Quality Properties of Emulsion-type Pork Sausages.

    Science.gov (United States)

    Lee, Hyun-Jin; Jung, Eun-Hee; Lee, Sang-Hwa; Kim, Jong-Hee; Lee, Jae-Joon; Choi, Yang-Ii

    2015-01-01

    This study was conducted to evaluate the quality properties of emulsion-type pork sausages when pork fat is replaced with vegetable oil mixtures during processing. Pork sausages were processed under six treatment conditions: T1 (20% pork fat), T2 (10% pork fat + 2% grape seed oil + 4% olive oil + 4% canola oil), T3 (4% grape seed oil + 16% canola oil), T4 (4% grape seed oil + 4% olive oil + 12% canola oil), T5 (4% grape seed oil + 8% olive oil + 8% canola oil), and T6 (4% grape seed oil + 12% olive oil + 4% canola oil). Proximate analysis showed significant (pfat content among the emulsion-type pork sausages. Furthermore, replacement with vegetable oil mixtures significantly decreased the ash content (psausages. Also, cholesterol content in T6 was significantly lower than T2 (psausages were significantly (preplacement. On the contrary, cohesiveness and springiness in the T4 group were similar to those of group T1. The unsaturated fatty acid content in emulsion-type pork sausages was increased by vegetable oil mixtures replacement. Replacement of pork fat with mixed vegetable oils had no negative effects on the quality properties of emulsion-type pork sausages, and due to its reduced saturated fatty acid composition, the product had the quality characteristics of the healthy meat products desired by consumers.

  11. Regular, high, and moderate intake of vegetables rich in antioxidants may reduce cataract risk in Central African type 2 diabetics

    Directory of Open Access Journals (Sweden)

    Mvitu M

    2012-06-01

    Full Text Available Moise Mvitu,1 Benjamin Longo-Mbenza,2 Dieudonné Tulomba,3 Augustin Nge31Department of Ophthalmology, University of Kinshasa, Democratic Republic of Congo; 2Faculty of Health Sciences, Walter Sisulu University, South Africa; 3Biostatistics Unit, Lomo Medical Center and Heart of Africa Center of Cardiology, Kinshasa, Democratic Republic of CongoBackground: Antioxidant nutrients found in popularly consumed vegetables, including red beans, are thought to prevent diabetic complications. In this study, we assessed the frequency and contributing factors of intake of fruits and vegetables rich in antioxidants, and we determined their impact on the prevention of diabetes-related cataract extraction.Methods: This was a cross-sectional study, run in Congo among 244 people with type 2 diabetes mellitus. An intake of ≥three servings of vegetables rich in antioxidants/day, intake of red beans, consumption of fruit, and cataract extraction were considered as dependent variables.Results: No patient reported a fruit intake. Intake of red beans was reported by 64 patients (26.2%, while 77 patients (31.6% reported ≥three servings of vegetables rich in antioxidants. High socioeconomic status (OR = 2.3; 95% CI: 1.1–12.5; P = 0.030 and moderate alcohol intake (OR = 4; 95% CI: 1.1–17.4; P = 0.049 were the independent determinants of eating ≥three servings of vegetables rich in antioxidants. Red beans intake (OR = 0.282; 95% CI: 0.115–0.687; P > 0.01 and eating ≥three servings of vegetables rich in antioxidants (OR = 0.256; 95% CI: 0.097–0.671; P = 0.006 were identified as independent and protective factors against the presence of cataracts (9.8% n = 24, whereas type 2 diabetes mellitus duration ≥3 years was the independent risk factor for cataract extraction (OR = 6.3; 95% CI: 2.1–19.2; P > 0.001 in the model with red beans intake and OR = 7.1; 95% CI: 2.3–22.2; P > 0.001 in the model with ≥three servings of vegetables rich in antioxidants

  12. Ecological recovery in an Arctic delta following widespread saline incursion.

    Science.gov (United States)

    Lantz, Trevor C; Kokelj, Steve V; Fraser, Robert H

    2015-01-01

    Arctic ecosystems are vulnerable to the combined effects of climate change and a range of other anthropogenic perturbations. Predicting the cumulative impact of these stressors requires an improved understanding of the factors affecting ecological resilience. In September of 1999, a severe storm surge in the Mackenzie Delta flooded alluvial surfaces up to 30 km inland from the coast with saline waters, driving environmental impacts unprecedented in the last millennium. In this study we combined field monitoring of permanent sampling plots with an analysis of the Landsat archive (1986-2011) to explore the factors affecting the recovery of ecosystems to this disturbance. Soil salinization following the 1999 storm caused the abrupt dieback of more than 30,000 ha of tundra vegetation. Vegetation cover and soil chemistry show that recovery is occurring, but the rate and spatial extent are strongly dependent on vegetation type, with graminoid- and upright shrub-dominated areas showing recovery after a decade, but dwarf shrub tundra exhibiting little to no recovery over this period. Our analyses suggest that recovery from salinization has been strongly influenced by vegetation type and the frequency of freshwater flooding following the storm. With increased ocean storm activity, rising sea levels, and reduced sea ice cover, Arctic coastal ecosystems will be more likely to experience similar disturbances in the future, highlighting the importance of combining field sampling with regional-scale remote sensing in efforts to detect, understand, and anticipate environmental change.

  13. Soil microbial communities are shaped by vegetation type and park age in cities under cold climate.

    Science.gov (United States)

    Hui, Nan; Jumpponen, Ari; Francini, Gaia; Kotze, D Johan; Liu, Xinxin; Romantschuk, Martin; Strömmer, Rauni; Setälä, Heikki

    2017-03-01

    Soil microbes play a key role in controlling ecosystem functions and providing ecosystem services. Yet, microbial communities in urban green space soils remain poorly characterized. Here we compared soil microbial communities in 41 urban parks of (i) divergent plant functional types (evergreen trees, deciduous trees and lawn) and (ii) different ages (constructed 10, ∼50 and >100 years ago). These microbial communities were also compared to those in 5 control forests in southern Finland. Our results indicate that, despite frequent disturbances in urban parks, urban soil microbes still followed the classic patterns typical of plant-microbe associations in natural environments: both bacterial and fungal communities in urban parks responded to plant functional groups, but fungi were under tighter control of plants than bacteria. We show that park age shaped the composition of microbial communities, possibly because vegetation in old parks have had a longer time to modify soil properties and microbial communities than in young parks. Furthermore, control forests harboured distinct but less diverse soil microbial communities than urban parks that are under continuous anthropogenic disturbance. Our results highlight the importance of maintaining a diverse portfolio of urban green spaces and plant communities therein to facilitate complex microbial communities and functions in urban systems.

  14. Categorizing Grassland Vegetation with Full-Waveform Airborne Laser Scanning: A Feasibility Study for Detecting Natura 2000 Habitat Types

    Directory of Open Access Journals (Sweden)

    András Zlinszky

    2014-08-01

    Full Text Available There is increasing demand for reliable, high-resolution vegetation maps covering large areas. Airborne laser scanning data is available for large areas with high resolution and supports automatic processing, therefore, it is well suited for habitat mapping. Lowland hay meadows are widespread habitat types in European grasslands, and also have one of the highest species richness. The objective of this study was to test the applicability of airborne laser scanning for vegetation mapping of different grasslands, including the Natura 2000 habitat type lowland hay meadows. Full waveform leaf-on and leaf-off point clouds were collected from a Natura 2000 site in Sopron, Hungary, covering several grasslands. The LIDAR data were processed to a set of rasters representing point attributes including reflectance, echo width, vegetation height, canopy openness, and surface roughness measures, and these were fused to a multi-band pseudo-image. Random forest machine learning was used for classifying this dataset. Habitat type, dominant plant species and other features of interest were noted in a set of 140 field plots. Two sets of categories were used: five classes focusing on meadow identification and the location of lowland hay meadows, and 10 classes, including eight different grassland vegetation categories. For five classes, an overall accuracy of 75% was reached, for 10 classes, this was 68%. The method delivers unprecedented fine resolution vegetation maps for management and ecological research. We conclude that high-resolution full-waveform LIDAR data can be used to detect grassland vegetation classes relevant for Natura 2000.

  15. Lake Bathymetric Aquatic Vegetation

    Data.gov (United States)

    Minnesota Department of Natural Resources — Aquatic vegetation represented as polygon features, coded with vegetation type (emergent, submergent, etc.) and field survey date. Polygons were digitized from...

  16. Biodiesel classification by base stock type (vegetable oil) using near infrared spectroscopy data

    Energy Technology Data Exchange (ETDEWEB)

    Balabin, Roman M., E-mail: balabin@org.chem.ethz.ch [Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich (Switzerland); Safieva, Ravilya Z. [Gubkin Russian State University of Oil and Gas, 119991 Moscow (Russian Federation)

    2011-03-18

    The use of biofuels, such as bioethanol or biodiesel, has rapidly increased in the last few years. Near infrared (near-IR, NIR, or NIRS) spectroscopy (>4000 cm{sup -1}) has previously been reported as a cheap and fast alternative for biodiesel quality control when compared with infrared, Raman, or nuclear magnetic resonance (NMR) methods; in addition, NIR can easily be done in real time (on-line). In this proof-of-principle paper, we attempt to find a correlation between the near infrared spectrum of a biodiesel sample and its base stock. This correlation is used to classify fuel samples into 10 groups according to their origin (vegetable oil): sunflower, coconut, palm, soy/soya, cottonseed, castor, Jatropha, etc. Principal component analysis (PCA) is used for outlier detection and dimensionality reduction of the NIR spectral data. Four different multivariate data analysis techniques are used to solve the classification problem, including regularized discriminant analysis (RDA), partial least squares method/projection on latent structures (PLS-DA), K-nearest neighbors (KNN) technique, and support vector machines (SVMs). Classifying biodiesel by feedstock (base stock) type can be successfully solved with modern machine learning techniques and NIR spectroscopy data. KNN and SVM methods were found to be highly effective for biodiesel classification by feedstock oil type. A classification error (E) of less than 5% can be reached using an SVM-based approach. If computational time is an important consideration, the KNN technique (E = 6.2%) can be recommended for practical (industrial) implementation. Comparison with gasoline and motor oil data shows the relative simplicity of this methodology for biodiesel classification.

  17. Factors Affecting Distribution of Vegetation Types on Abandoned Cropland in the Hilly-Gullied Loess Plateau Region of China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A study was conducted in the forest-steppe region of the Loess Plateau to provide insight into the factors affecting the process of vegetation establishment,and to provide recommendations for the selection of indigenous species in order to speed up the succession process and to allow the establishment of vegetation more resistant to soil erosion.Four distinctive vegetation types were identified,and their distribution was affected not only by the time since abandonment but also by other environmental factors,mainly soil water and total P in the upper soil layers.One of the vegetation types,dominated by Artemisia scoparia,formed the early successional stage after abandonment while the other three types formed later successional stages with their distribution determined by the soil water content and total P.It can be concluded that the selection of appropriate species for introduction to accelerate succession should be determined by the local conditions and especially the total P concentration and soil water content.

  18. Arctic Newcomers

    DEFF Research Database (Denmark)

    Tonami, Aki

    2013-01-01

    Interest in the Arctic region and its economic potential in Japan, South Korea and Singapore was slow to develop but is now rapidly growing. All three countries have in recent years accelerated their engagement with Arctic states, laying the institutional frameworks needed to better understand an...

  19. Arctic methane

    NARCIS (Netherlands)

    Dyupina, E.; Amstel, van A.R.

    2013-01-01

    What are the risks of a runaway greenhouse effect from methane release from hydrates in the Arctic? In January 2013, a dramatic increase of methane concentration up to 2000 ppb has been measured over the Arctic north of Norway in the Barents Sea. The global average being 1750 ppb. It has been sugges

  20. VEGETATION TYPE AND THE INTERTIDAL MACROINVERTEBRATE FAUNA OF A BRACKISH MARSH: PHRAGMITES VS. SPARTINA

    Science.gov (United States)

    The responses of tidal marsh macroinvertebrate assemblages to the conversion of Spartina alterniflora marshes to marshes dominated by the invasive reed, Phragmites australis, are poorly understood. Changes in edaphic, vegetative, hydrological, and detrital conditions that attend ...

  1. Vegetation Cover Types of St. Vincent Island N.W.R.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of this vegetative study on St. Vincent National Wildlife Refuge were to: (1) identify and describe the major plant communities and associations on...

  2. Identification of Forest Vegetation Using Vegetation Indices

    Institute of Scientific and Technical Information of China (English)

    Yuan Jinguo; Wang Wei

    2004-01-01

    Spectral feature of forest vegetation with remote sensing techniques is the research topic all over the world, because forest plays an important role in human beings' living environment. Research on vegetation classification with vegetation index is still very little recently. This paper proposes a method of identifying forest types based on vegetation indices,because the contrast of absorbing red waveband with reflecting near-infrared waveband strongly for different vegetation types is recognized as the theoretic basis of vegetation analysis with remote sensing. Vegetation index is highly related to leaf area index, absorbed photosynthetically active radiation and vegetation cover. Vegetation index reflects photosynthesis intensity of plants and manifests different forest types. According to reflectance data of forest canopy and soil line equation NIR=1.506R+0.0076 in Jingyuetan, Changchun of China, many vegetation indices are calculated and analyzed. The result shows that the relationships between vegetation indices and forest types are that perpendicular vegetation index (PVI) identifies broadleaf forest and coniferous forest the most easily;the next is transformed soil-adjusted vegetation index(TSVI) and modified soil-adjusted vegetation index(MSVI), but their calculation is complex. Ratio vegetation index (RVT) values of different coniferous forest vary obviously, so RVI can classify conifers.Therefore, the combination of PVI and RVI is evaluated to classify different vegetation types.

  3. Measurement-based upscaling of Pan Arctic Net Ecosystem Exchange: the PANEEx project

    Science.gov (United States)

    Njuabe Mbufong, Herbert; Kusbach, Antonin; Lund, Magnus; Persson, Andreas; Christensen, Torben R.; Tamstorf, Mikkel P.; Connolly, John

    2016-04-01

    The high variability in Arctic tundra net ecosystem exchange (NEE) of carbon (C) can be attributed to the high spatial heterogeneity of Arctic tundra due to the complex topography. Current models of C exchange handle the Arctic as either a single or few ecosystems, responding to environmental change in the same manner. In this study, we developed and tested a simple pan Arctic NEE (PANEEx) model using the Misterlich light response curve (LRC) function with photosynthetic photon flux density (PPFD) as the main driving variable. Model calibration was carried out with eddy covariance carbon dioxide (CO2) data from 12 Arctic tundra sites. The model input parameters (Fcsat, Rd and α) were estimated as a function of air temperature (AirT) and leaf area index (LAI) and represent specific characteristics of the NEE-PPFD relationship, including the saturation flux, dark respiration and initial light use efficiency, respectively. LAI and air temperature were respectively estimated from empirical relationships with remotely sensed normalized difference vegetation index (NDVI) and land surface temperature (LST). These are available as MODIS Terra product MOD13Q1 and MOD11A1 respectively. Therefore, no specific knowledge of the vegetation type is required. The PANEEx model captures the spatial heterogeneity of the Arctic tundra and was effective in simulating 77% of the measured fluxes (r2 = 0.72, p agreement between the measured and modeled NEE may result from the disparity between ground-based measured LAI (used in model calibration) and remotely sensed LAI (estimated from NDVI and used in NEE estimation). Moreover, our results suggests that using simple linear regressions may be inadequate as parameters estimated using multiple linear regression showed better agreement between measured and modeled data. We propose recalibrating the model using multiple linear relationships between environmental variables and LRC parameters. This model could contribute significantly to

  4. Arctic Watch

    Science.gov (United States)

    Orcutt, John; Baggeroer, Arthur; Mikhalevsky, Peter; Munk, Walter; Sagen, Hanne; Vernon, Frank; Worcester, Peter

    2015-04-01

    The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This will be driven by increased demand for energy and the marine resources of an Arctic Ocean more accessible to ships. Oil and gas exploration, fisheries, mineral extraction, marine transportation, research and development, tourism and search and rescue will increase the pressure on the vulnerable Arctic environment. Synoptic in-situ year-round observational technologies are needed to monitor and forecast changes in the Arctic atmosphere-ice-ocean system at daily, seasonal, annual and decadal scales to inform and enable sustainable development and enforcement of international Arctic agreements and treaties, while protecting this critical environment. This paper will discuss multipurpose acoustic networks, including subsea cable components, in the Arctic. These networks provide communication, power, underwater and under-ice navigation, passive monitoring of ambient sound (ice, seismic, biologic and anthropogenic), and acoustic remote sensing (tomography and thermometry), supporting and complementing data collection from platforms, moorings and autonomous vehicles. This paper supports the development and implementation of regional to basin-wide acoustic networks as an integral component of a multidisciplinary, in situ Arctic Ocean Observatory.

  5. Reflectance properties of selected arctic-boreal land cover types: field measurements and their application in remote sensing

    Directory of Open Access Journals (Sweden)

    J. I. Peltoniemi

    2008-03-01

    Full Text Available We developed a mobile remote sensing measurement facility for spectral and anisotropic reflectance measurements. We measured reflection properties (BRF of over 100 samples from most common land cover types in boreal and subarctic regions. This extensive data set serves as a unique reference opportunity for developing interpretation algorithms for remotely sensed materials as well as for modelling climatic effects in the boreal and subarctic zones.

    Our goniometric measurements show that the reflectances of the most common land cover types in the boreal and subarctic region can differ from each other by a factor of 100. Some types are strong forward scatterers, some backward scatterers, some reflect specularly, some have strong colours, some are bright in visual, some in infrared. We noted that spatial variations in reflectance, even among the same type of vegetation, can be well over 20%, diurnal variations of the same order and seasonal variation often over a factor of 10. This has significant consequences on the interpretation of satellite and airborne images and on the development of radiation regime models in both optical remote sensing and climate change research.

    We propose that the accuracy of optical remote sensing can be improved by an order of magnitude, if better physical reflectance models can be introduced. Further improvements can be reached by more optimised design of sensors and orbits/flight lines, by the effective combining of several data sources and better processing of atmospheric effects. We conclude that more extensive and systematic laboratory experiments and field measurements are needed, with more modelling effort.

  6. The Evolving Arctic: Current State of U.S. Arctic Policy

    Science.gov (United States)

    2013-09-01

    allow for an “Arctic Treaty ” akin to the Antarctic Treaty .50 There has been some dissent on this issue among some critics who believe an “Arctic... Treaty ” should be signed, and like the Antarctic Treaty , should ban military activities and commercial fishing.51 Unlike the Arctic that contains the...scientific research and not the sovereign territory of any one nation. An Antarctic -type treaty in the Arctic would require the nations signing it to give up

  7. Vegetation Map and Vegetation Monographs of China

    Institute of Scientific and Technical Information of China (English)

    GUO Ke

    2010-01-01

    @@ Vegetation Map of China As the most significant component of an ecosystem,vegetation plays the most important role in maintaining biodiversity and providing the necessary resources for human beings.A vegetation map shows the major vegetation types of a region and their geographic distribution patterns.

  8. Impact of vegetation types on soil organic carbon stocks SOC-S in Mediterranean natural areas

    Science.gov (United States)

    Parras-Alcántara, Luis; Lozano-García, Beatriz; Cantudo-Pérez, Marta

    2015-04-01

    Soils play a key role in the carbon geochemical cycle because they can either emit large quantities of CO2 or on the contrary they can act as a store for carbon. Agriculture and forestry are the only activities that can achieve this effect through photosynthesis and the carbon incorporation into carbohydrates (Parras-Alcántara et al., 2013). The Mediterranean evergreen oak Woodland (MEOW - dehesa) is a type of pasture with scattered evergreen and deciduous oak stands in which cereals are often grown under the tree cover. It is a system dedicated to the combined production of Iberian swine, sheep, fuel wood, coal and cork as well as to hunting. These semi-natural areas still preserve some of the primitive vegetation of the Mediterranean oak forests. The dehesa is a pasture where the herbaceous layer is comprised of either cultivated cereals such as oat, barley and wheat or native vegetation dominated by annual species, which are used as grazing resources. These Iberian open woodland rangelands (dehesas) have been studied from different points of view: hydrologically, with respect to soil organic matter content, as well as in relation to gully erosion, topographical thresholds, soil erosion and runoff production, soil degradation and management practices…etc, among others. The soil organic carbon stock capacity depends not only on abiotic factors such as the mineralogical composition and the climate, but also on soil use and management (Parras et al., 2014 and 2015). In Spanish soils, climate, use and management strongly affect the carbon variability, mainly in soils in dry Mediterranean climates characterized by low organic carbon content, weak structure and readily degradable soils. Hontoria et al. (2004) emphasized that the climate and soil use are two factors that greatly influence carbon content in the Mediterranean climate. This research sought to analyze the SOC stock (SOCS) variability in MEOW - dehesa with cereals, olive grove and Mediterranean oak forest

  9. Nutritional differences and leaf acclimation of climbing plants and the associated vegetation in different types of an Andean montane rainforest.

    Science.gov (United States)

    Salzer, J; Matezki, S; Kazda, M

    2006-03-01

    Climbing plants are known to play an important role in tropical forest systems, but key features for their distribution are only partly understood. Investigation was carried out to find if climbers differ from self-supporting vegetation in their adjustment of leaf parameters over a wide variety of light regimes in different forest types along an altitudinal gradient. Relative photon flux density (PFDrel) was assessed above 75 pairs of strictly linked climbers and supporting vegetation on seven plots between 2,020 and 2,700 m a.s.l. along a mountain range in South-Ecuador up to the Páramo vegetation. Leaf samples from both growth forms were analyzed for leaf area (LA), specific leaf mass (LMA), mass and area-based carbon and nitrogen concentration (C, Carea, N, and Narea) and concentrations of P, K, Ca, Mg, Mn and Al. Leaf size of climbers was independent of general light condition, whereas the leaf size of the self-supporting vegetation increased in shade. LMA increased as expected with altitude and irradiance for both growth forms, but climbers generally built smaller leaves with lower LMA. N, P, and K concentrations were higher in the leaves of climbers than in their supporters. Relationships of LMA and Narea to the light conditions were more pronounced within the climbers than within their supporters. Slope for the regression between climber's Narea and LMA was twice as steep as for the supporter leaves. Al accumulators were only found within the self-supporting vegetation. The investigated traits indicate improved adjustment towards light supply within climbers compared to self-supporting vegetation. Thus climbing plants seem to have a higher potential trade off in resource-use efficiency regarding irradiance and nutrients.

  10. Trophodynamics of current use pesticides and ecological relationships in the Bathurst region vegetation-caribou-wolf food chain of the Canadian Arctic.

    Science.gov (United States)

    Morris, Adam D; Muir, Derek C G; Solomon, Keith R; Teixeira, Camilla; Duric, Mark; Wang, Xiaowa

    2014-09-01

    The bioaccumulation of current use pesticides (CUPs) and stable isotopes of carbon and nitrogen were investigated in vegetation-caribou-wolf food chain in the Bathurst region (Nunavut, Canada). Volumetric bioconcentration factors (BCF(v)) in vegetation were generally greatest for dacthal (10-12) ≥ endosulfan sulfate (10-11) > ß-endosulfan (>9.0-9.7) ≥ pentachloronitrobenzene (PCNB; 8.4-9.6) > α-endosulfan (8.3-9.3) > chlorpyrifos (8.0-8.7) >chlorothalonil (7.6-8.3). The BCF(v) values in vegetation were significantly correlated with the logarithm of the octanol-air partition coefficients (log K(OA)) of CUPs (r(2)  = 0.90, p = 0.0040), although dacthal was an outlier and not included in this relationship. Most biomagnification factors (BMFs) for CUPs in caribou:diet comparisons were significantly less than 1. Similarly, the majority of wolf:caribou BMFs were either significantly less than 1 or were not statistically greater than 1. Significant trophic magnification factors (TMFs) were all less than 1, indicating that these CUPs exhibit trophic dilution through this terrestrial food chain. The log K(OA) reasonably predicted bioconcentration in vegetation for most CUPs but was not correlated with BMFs or TMFs in mammals. Our results, along with those of metabolic studies, suggest that mammals actively metabolize these CUPs, limiting their biomagnification potential despite entry into the food chain through effective bioconcentration in vegetation.

  11. Wieslander Vegetation

    Data.gov (United States)

    California Department of Resources — Digital version of the 1945 California Vegetation Type Maps by A. E. Wieslander of the U.S. Forest Service. Source scale of maps are 1:100,000. These compiled maps...

  12. Invasive Plant-Soil Feedbacks and Ecosystem Resistance and Resilience: A Comparison of Three Vegetation Types in California

    OpenAIRE

    Dickens, Sara Jo Myrtle

    2010-01-01

    ABSTRACT OF THE DISSERTATIONInvasive Plant-Soil Feedbacks and Ecosystem Resistance and Resilience: A Comparison of Three Vegetation Types in CaliforniaBy Sara Jo DickensDoctor of Philosophy, Graduate Program in Plant BiologyUniversity of California, Riverside, December 2010Dr Edith B. Allen, ChairpersonEcosystem processes are strongly dependant on plant-soil feedbacks. The invasion of exotic plant species can result in the introduction of novel traits capable of de-coupling native plant-soil ...

  13. Root Effect of Three Vegetation Types on Shoreline Stabilization of Chongming Island, Shanghai

    Institute of Scientific and Technical Information of China (English)

    DU Qin; ZHONG Qi-Cheng; WANG Kai-Yun

    2010-01-01

    Coastal erosion is currently a major problem along the southern coast of Chongming Island, Shanghai. To enhance the erosion protection ability of coastal shelterbelts, two woody tree species, Taxodium ascendens and Salix babylonica, were planted separately into Phragmites australis + Scirpus mariqueter communities in 2006. Two years later, we investigated whether either of these experiments reduced erosion and increased stability in the native herbaceous plant community. We also examined soil stability and root length density under T. ascendens added, S. babylonica added and native herbaceous vegetation conditions along an intertidal gradient from the soil surface to a depth of 40 cm in each experiment, thus to determine the capacity of T. ascendens and S. babylonica to contribute to shoreline stabilization. Topsoil under the native vegetation had greater stability at the middle and higher intertidal zones because its soil stability index and root length density were significantly higher than in the T. ascendens or S. babylonica planted communities. The effect of T.ascendens on soil stability was not generally better than that of the native vegetation. Only at the 20-30 cm soil depth of the middle intertidal zone and in the 10-20 cm layer of the higher intertidal zone the soil stability index and root length densities under the T. ascendens added condition were significantly higher (P < 0.05) than those of the native vegetation.The S. babylonica planted soil had greater stability in the deeper soil layer than the soil under either the native vegetation or the T. ascendens added condition, and its soil stability index and root length density were significant higher (P < 0.05) than those of other vegetation conditions at the 30-40 cm soil depth for the lower intertidal zone and at the 20-40 cm layer for middle and higher intertidal zones.

  14. Evaluation of vegetation types in the West Zagros (Beiranshahr region as a case study, in Lorestan Province, Iran

    Directory of Open Access Journals (Sweden)

    ATENA ESLAMI FAROUJI

    2016-04-01

    Full Text Available Farouji AE, Khodayari H. 2016. Evaluation of vegetation types in the West Zagros (Beiranshahr region as a case study, in Lorestan Province, Iran. Biodiversita 17: 1-10. The accurate identification of plant communities and their distribution are classical tools for mapping and classification of plants. Plants are strongly sensitive against changing environmental conditions. Moreover, Iran has a special position in Asia which has been creating a diverse ecosystem. Close floristic studies are necessary for precise determination of diversity and uniformity. To determine plant species in different vegetation types in Beiran shahr region, modified multi-scale Whittaker plots were constructed. This studied area was about 20000 ha and located in Northwest to Southwest of Iran. Eighty-nine plots were made in different longitude and latitudes. The minimum and maximum heights were 1101 and 2489 m asl., respectively. Within each modified multi-scale plots, each species was explored. Of 608 species, 498 and 97 are belonging to dicotyledons and monocotyledons, and remained 13 species were Pteridophytes. As measured, Therophyte and Champhyte are the dominant and recessive form of life in studied area. Based on species of each plot and subplots, mean Jaccard's coefficient, number of unique species and mean unique species/plot were estimated for each vegetation type. It is obvious that there is a clear correlation between Slopes of the species-log area curve and Mean number of unique species per plot.

  15. Effects of vegetation type on soil microbial community structure and catabolic diversity assessed by polyphasic methods in North China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Soil microbes play a major role in ecological processes and are closely associated with the aboveground plant community. In order to understand the effects of vegetation type on the characteristics of soil microbial communities, the soil microbial communities were assessed by plate counts, phospholipid fatty acid (PLFA) and Biolog microplate techniques in five plant communities, i.e., soybean field (SF), artificial turf (AT), artificial shrub (AS), natural shrub (NS), and maize field (MF) in Jinan, Shandong Province, North China. The results showed that plant diversity had little discernible effect on microbial biomass but a positive impact on the evennessof utilized substrates in Biolog microplate. Legumes could significantly enhance the number of cultural microorganisms, microbial biomass, and community catabolic diversity. Except for SF dominated by legumes, the biomass of fungi and the catabolic diversity of microbial community were higher in less disturbed soil beneath NS than in frequently disturbed soils beneath the other vegetation types. These results confirmed that high number of plant species, legumes, and natural vegetation types tend to support soil microbial communities with higher function. The present study also found a significant correlation between the number of cultured bacteria and catabolic diversity of the bacterial community. Different research methods led to varied results in this study. The combination of several approaches is recommended for accurately describing the characteristics of microbial communities in many respects.

  16. Energy partitioning and environmental influence factors in different vegetation types in the GEWEX Asian Monsoon Experiment

    Science.gov (United States)

    Liu, Fengshan; Tao, Fulu; Li, Shenggong; Zhang, Shuai; Xiao, Dengpan; Wang, Meng

    2014-12-01

    Environmental influences upon energy balance in areas of different vegetation types (i.e., forest at Kog-Ma in Thailand and at Yakutsk in Russia, grassland at Amdo in Chinese Tibet and at Arvaikheer in Mongolia, and mixed farmland at Tak in Thailand) in the GEWEX Asian Monsoon Experiment were investigated. The sites we investigated are geographically and climatologically different; and consequently had quite large variations in temperature ( T), water vapor pressure deficit (VPD), soil moisture (SM), and precipitation (PPT). During May-October, the net radiation flux ( R n) (in W·m-2) was 406.21 at Tak, 365.57 at Kog-Ma, 390.97 at Amdo, 316.65 at Arvaikheer, and 287.10 at Yakutsk. During the growing period, the R n partitioned into latent heat flux ( λE/ R n) was greater than that partitioned into sensible heat flux ( H/ R n) at Tak and at Kog-Ma. In contrast, λE/ R n was lower than H/ R n at Arvaikheer, H/ R n was less than λE/ R n between DOY 149 and DOY 270 at Amdo, and between DOY 165 and DOY 235 at Yakutsk. The R n partitioned into ground heat flux was generally less than 0.15. The short-wave albedo was 0.12, 0.18, and 0.20 at the forest, mixed land, and grass sites, respectively. At an hourly scale, energy partitions had no correlation with environmental factors, based on average summer halfhourly values. At a seasonal scale energy partitions were linearly correlated (usually p<0.05) with T, VPD, and SM. The λE/ R n increased with increases in SM, T, and VPD at forest areas. At mixed farmlands, λE/ R n generally had positive correlations with SM, T, and VPD, but was restrained at extremely high values of VPD and T. At grasslands, λE/ R n was enhanced with increases of SM and T, but was decreased with VPD.

  17. Effect of vegetation types on soil arbuscular mycorrhizal fungi and nitrogen-fixing bacterial communities in a karst region.

    Science.gov (United States)

    Liang, Yueming; Pan, Fujing; He, Xunyang; Chen, Xiangbi; Su, Yirong

    2016-09-01

    Arbuscular mycorrhizal (AM) fungi and nitrogen-fixing bacteria play important roles in plant growth and recovery in degraded ecosystems. The desertification in karst regions has become more severe in recent decades. Evaluation of the fungal and bacterial diversity of such regions during vegetation restoration is required for effective protection and restoration in these regions. Therefore, we analyzed relationships among AM fungi and nitrogen-fixing bacteria abundances, plant species diversity, and soil properties in four typical ecosystems of vegetation restoration (tussock (TK), shrub (SB), secondary forest (SF), and primary forest (PF)) in a karst region of southwest China. Abundance of AM fungi and nitrogen-fixing bacteria, plant species diversity, and soil nutrient levels increased from the tussock to the primary forest. The AM fungus, nitrogen-fixing bacterium, and plant community composition differed significantly between vegetation types (p fungi and nitrogen-fixing bacteria, respectively. Available phosphorus, total nitrogen, and soil organic carbon levels and plant richness were positively correlated with the abundance of AM fungi and nitrogen-fixing bacteria (p fungi and nitrogen-fixing bacteria increased from the tussock to the primary forest and highlight the essentiality of these communities for vegetation restoration.

  18. Predictors of College-Student Food Security and Fruit and Vegetable Intake Differ by Housing Type

    Science.gov (United States)

    Mirabitur, Erica; Peterson, Karen E.; Rathz, Colleen; Matlen, Stacey; Kasper, Nicole

    2016-01-01

    Objective: We assessed whether college-student characteristics associate with food security and fruit and vegetable (FV) intake and whether these associations differ in students in housing with and without food provision. Participants: 514 randomly-sampled students from a large, Midwestern, public university in 2012 and 2013 Methods: Ordered…

  19. Effect of harvest at different times of day on the physical and chemical characteristics of vegetable-type soybean

    Directory of Open Access Journals (Sweden)

    Andréia Cristina Santana

    2012-06-01

    Full Text Available The objective of this study was to evaluate the effect of harvest at different times of day on the chemical and physical characteristics of vegetable-type soybean BRS 267 cultivar, harvested at the R6 stage (seed development and to compare it with that on the grains harvested at the R8 stage (maturation. The pods of the BRS 267 cultivar were harvested at the R6 stage (at 8:00 AM, 12:00 AM, and 6:00 PM, the color parameters were evaluated, and the grains were analyzed for chemical composition, activity inhibitor trypsin, phytic acid content, starch, sugars, fatty acids, and isoflavones. No differences were observed among the different harvest times in terms of the chemical constituents of vegetable-type soybean BRS 267 cultivar harvested at the R6 stage. Isoflavones content did not change with different harvest times, and the aglycone forms (daidzein, glycitein, and genistein were found in smaller quantities at the R6 stage compared to the R8 stage. The color of the pods of soybean BRS 267 cultivar, harvested at the R6 stage did not change with different harvest times. The grains harvested at the R6 stage had lower protein content, phytic acid, and sucrose and higher levels of lipids, carbohydrates, starch, glucose, fructose, stachyose, and linolenic acids than those collected at the R8 stage. The different times of harvest did not affect the quality of the vegetable-type soybean BRS 267 cultivar harvested at stage R6. Nevertheless, it is recommended to harvest in the morning, when the temperature is milder, like other vegetables, to facilitate and optimize its marketing and in natura consumption.

  20. Study on Types and Features of Urban Vegetation in Urumqi%乌鲁木齐城市植被类型及其特点

    Institute of Scientific and Technical Information of China (English)

    尹林克; 南伟疆; 严成; 王蕾; 姜逢清; 昝勤

    2011-01-01

    根据人为干扰程度、群落功能以及优势建群种,将乌鲁木齐市城市植被划分为自然植被、半自然植被和人工植被3个植被类、13个植被组和125个植被型。自然植被类划分为7个植被组82个植被型;半自然植被类划分为4个植被组33个植被型;人工植被类划分为2个植被组10个植被型。乌鲁木齐自然植被类谱系完整,旱生和超旱生灌木、半灌木及多年生草本优势明显。半自然植被类由于人类活动的扰动,植物群落物种数量较自然植被明显增多,乔灌木比例加大,上层乔灌木种类大部分为人工栽培种,草本组多为原生和外来的野生植物种,部分物种呈斑块状分布并沿灌溉带呈线状分布,物种多样性指数较高。人工植被类中园林绿地破碎度较高,呈点、块、条状散布于城市中心,覆盖率低,种群间和群落间关联度小。其中,以防护林绿地为主,群落中引入归化种和外来种的比例过高;受市场经济影响,农业植被组以粮食、蔬菜和油料为主。%According to the degree of human disturbance,community functions and advantages of the dominant and constructive species,in this paper,urban vegetation in Urumqi was divided into three parts,i.e.the natural vegetation,semi-natural vegetation and artificial vegetation,including 3 vegetation races,13 vegetation groups and 125 vegetation types.Natural vegetation race is classified into 7 vegetation groups,i.e.the coniferous forest vegetation group,broadleaf forest vegetation group,shrub vegetation group,desert vegetation group,meadow vegetation group,steppe vegetation group and alpine vegetation group with 82 vegetation types;semi-natural vegetation race is divided into 4 vegetation groups,i.e.the broadleaf forest vegetation group,shrub vegetation group,herbaceous vegetation group and partner person vegetation group with 33 vegetation types;artificial vegetation race is classified into 2 vegetation groups

  1. [Comparison of soil fertility among open-pit mine reclaimed lands in Antaibao regenerated with different vegetation types].

    Science.gov (United States)

    Wang, Xiang; Li, Jin-chuan; Yue, Jian-ying; Zhou, Xiao-mei; Guo, Chun-yan; Lu, Ning; Wang, Yu-hong; Yang, Sheng-quan

    2013-09-01

    Re-vegetation is mainly applied into regeneration in opencast mine to improve the soil quality. It is very important to choose feasible vegetation types for soil restoration. In this study, three typical forest restoration types were studied at Antaibao mine, namely, Medicago sativa, mixed forests Pinus taebelaefolius-Robinia pseudoacacia-Caragana korshinskii and Elaeagnus angustifolia-Robinia pseudoacacia-Caragana korshinskii-Hipophae rhamnoides, to determine the nutrient contents and enzyme activities in different soil layers. The results showed that re-vegetation markedly increased soil nutrient contents and the enzyme activities during the restoration process. The nutrient content of soil in the P. taebelaefolius-R. pseudoacacia-C. korshinskii mixed forest field was significantly higher than those in other plots. It was found that the soil of the P. taebelaefolius-R. pseudoacacia-C. korshinskii mixed forest had the highest integrated fertility index values. In conclusion, the restoration effects of the P. zaebelaefolius-R. pseudoacacia-C. Korshinskii mixed forest was better than that of E. angustifolia-R. pseudoacacia-C. korshinskii-H. rhamnoides, while M. sativa grassland had the least effect.

  2. Feed intake and activity level of two broiler genotypes foraging different types of vegetation in the finishing period

    DEFF Research Database (Denmark)

    Almeida, Gustavo Fonseca; Hinrichsen, Lena Karina; Horsted, Klaus;

    2012-01-01

    were included in a 2 × 2 factorial design with groups of 25 birds replicated 3 times. The use of outdoor areas, performance, and forage intake were investigated. To identify possible differences in foraging activity, the use of the range was monitored one day per week at 4 different times of the day......A study was performed with 2 broiler genotypes (slow and medium growth) restricted in supplementary feed and foraging 2 different mixed vegetations (grass/clover or chicory) to identify possible benefits of herbage on nutrition during the finishing period (80 to 113 d of age). Three hundred birds....... Feed intake from foraging was estimated by killing 4 birds per plot (2 males and 2 females) in the morning and in the evening on 3 d during the experiment and measuring crop content. Vegetation type did not influence broiler use of the free-range area, feed intake, or performance. Differences...

  3. Effect of non-crop vegetation types on conservation biological control of pests in olive groves

    OpenAIRE

    2013-01-01

    Conservation biological control (CBC) is an environmentally sound potential alternative to the use of chemical insecticides. It involves modifications of the environment to promote natural enemy activity on pests. Despite many CBC studies increasing abundance of natural enemies, there are far fewer demonstrations of reduced pest density and very little work has been conducted in olive crops. In this study we investigated the effects of four forms of non-crop vegetation on the abundance of two...

  4. Soil carbon fractions and enzyme activities under different vegetation types on the Loess Plateau of China

    OpenAIRE

    Zhang, Haixin; Zeng, Quanchao; An, Shaoshan; Dong, Yanghong; Darboux, Frédéric

    2016-01-01

    Vegetation restoration was effective way of protecting soil erosion and water conservation on the Loess Plateau. Carbon fractions and enzyme activities were sensitive parameters for assessment of soil remediation through revegetation. Forest, forest steppe and grassland soils were collected at 0–5 cm and 5–20 cm soil layers in Yanhe watershed, Shaanxi Province. Urease, sucrase, alkaline phosphatase, soil organic carbon (SOC), microbial biomass carbon (MBC), easily ox...

  5. Type utilization of baked-smashed sweet potato and vegetables on patisserie product

    Science.gov (United States)

    Ana; Subekti, S.; Sudewi; Perdani, E. N.; Hanum, F.; Suciani, T.; Tania, V.

    2016-04-01

    The research was an experimental study in Green Skill Patisserie Course using Project-Based Learning model. It aims to complete the project development of pie named guramnis rainbow pie. Several experiments were carried out to produce a pie dough crust mixed with baked-smashed sweet potato and added with vegetables extract as the food coloring. The experiment method in order to make a better appearance or an attractive shape and to have more nutrition. In addition, the pie was filled with a mixture of sweet and sour gurame as Indonesian traditional food. By applying an organoleptic test to 10 respondents, the result shows that pie dough recipe using flour substituted by baked-smashed sweet potato with 2:1 of a ratio. Coloring pie dough adding extract vegetables (carrots, beets and celery) as color. We found that pie dough has more interesting pie color (90%) and the texture of the pie with a quite level of crispness (60%). Moreover, the pie taste is fairly (70%) and tasty (70%). Nutritional analysis results show that per size, serving guramnis rainbow pie contains energy as much as 81.72 calories, carbohydrates 12.5 grams, fat 2.32 grams and 2.77 grams of protein. The main findings are the pie appearance and taste was different compared to the previous pies because of the pie was served with gurame asam manis as the filling and had flour and cilembu sweet potato as the basic ingredients. The color of guramnis rainbow pie was resulted not only from food coloring but also from vegetables extract namely carrot (orange), bit (red), and salary (green). Thus, it had many benefits for health and adds the nutrition. The researchers recommend a further study in order to make pie dough with baked sweet potato and vegetables extract having an optimal level of crispness.

  6. Millennial-scale vegetation changes in the north-eastern Russian Arctic during the Pliocene/Pleistocene transition (2.7-2.5 Ma) inferred from the pollen record of Lake El'gygytgyn

    Science.gov (United States)

    Andreev, Andrei A.; Tarasov, Pavel E.; Wennrich, Volker; Melles, Martin

    2016-09-01

    The sediment record of Lake El'gygytgyn (67°30‧N, 172°05‧E) spans the past 3.6 Ma and provides unique opportunities for qualitative and quantitative reconstructions of the regional paleoenvironmental history of the terrestrial Arctic. Millennial-scale pollen studies of the sediments that accumulated during the Late Pliocene and Early Pleistocene (ca. 2.7 to 2.5 Ma) demonstrate orbitally-driven vegetation and climate changes during this transitional interval. Pollen spectra show a significant vegetation shift at the Pliocene/Pleistocene boundary that is, however, delayed by a few thousand years compared to lacustrine response. About 2.70-2.68 Ma the vegetation at Lake El'gygytgyn, currently a tundra area was mostly dominated by larch forests with some shrub pine, shrub alder and dwarf birch in understory. During the marine isotope stages G3 and G1, ca. 2.665-2.647 and 2.625-2.617 Ma, some spruce trees grew in the local larch-pine forests, pointing to relatively warm climate conditions. At the beginning of the Pleistocene, around 2.588 Ma, a prominent climatic deterioration led to a change from larch-dominated forests to predominantly treeless steppe- and tundra-like habitats. Between ca. 2.56-2.53 Ma some climate amelioration is reflected by the higher presence of coniferous taxa (mostly pine and larch, but probably also spruce) in the area. After 2.53 Ma a relatively cold and dry climate became dominant again, leading to open steppe-like and shrubby environments followed by climate amelioration between ca. 2.510 and 2.495 Ma, when pollen assemblages show that larch forests with dwarf birch and shrub alder still grew in the lake's vicinity. Increased contents of green algae colonies (Botryococcus) remains and Zygnema cysts around 2.691-2.689, 2.679-2.677, 2.601-2.594, 2.564-2.545, and 2.532-2.510 Ma suggest a spread of shallow-water environments most likely due to a lake-level lowering. These events occurred simultaneously with dry climate conditions inferred

  7. Dissolved organic carbon (DOC) concentrations in UK soils and the influence of soil, vegetation type and seasonality.

    Science.gov (United States)

    van den Berg, Leon J L; Shotbolt, Laura; Ashmore, Mike R

    2012-06-15

    Given the lack of studies which measured dissolved organic carbon (DOC) over long periods, especially in non-forest habitat, the aim of this study was to expand the existing datasets with data of mainly non-forest sites that were representative of the major soil and habitat types in the UK. A further aim was to predict DOC concentrations from a number of biotic and abiotic explanatory variables such as rainfall, temperature, vegetation type and soil type in a multivariate way. Pore water was sampled using Rhizon or Prenart samplers at two to three week intervals for 1 year. DOC, pH, organic carbon, carbon/nitrogen (C:N) ratios of soils and slope were measured and data on vegetation, soil type, temperature and precipitation were obtained. The majority of the variation in DOC concentrations between the UK sites could be explained by simple empirical models that included annual precipitation, and soil C:N ratio with precipitation being negatively related to DOC concentrations and C:N ratio being positively related to DOC concentrations. Our study adds significantly to the data reporting DOC concentrations in soils, especially in grasslands, heathlands and moorlands. Broad climatic and site factors have been identified as key factors influencing DOC concentrations.

  8. Deeper snow alters soil nutrient availability and leaf nutrient status in high Arctic tundra

    DEFF Research Database (Denmark)

    Semenchuk, Philipp R.; Elberling, Bo; Amtorp, Cecilie;

    2015-01-01

    Nitrogen (N) mineralization, nutrient availability, and plant growth in the Arctic are often restricted by low temperatures. Predicted increases of cold-season temperatures may be important for plant nutrient availability and growth, given that N mineralization is also taking place during the cold...... season. Changing nutrient availability may be reflected in plant N and chlorophyll content and lead to increased photosynthetic capacity, plant growth, and ultimately carbon (C) assimilation by plants. In this study, we increased snow depth and thereby cold-season soil temperatures in high Arctic......, Bistorta vivipara, and Luzula arcuata at peak season. Nutrient availability was significantly higher with increased snow depth in the two mesic meadow vegetation types, but not in the drier heath vegetation. Nitrogen concentrations and delta N-15 values of Salix leaves were significantly higher in all...

  9. RADARSAT-1 Background Mission Monitoring of the Arctic

    Science.gov (United States)

    2005-07-25

    coverage of the Arctic would result into valuable temporal records of a part of the world that is particularly sensitive to global climate change...used to define the boundary: The Arctic Circle, a climatic marker, or a vegetational marker. The Arctic Circle is simply the area of mid-night sun...boundary, delineated by the treeline , or the boundary between the Tundra and the (Boreal) forest alone is not appropriate as it is subject to

  10. Community Structure of Skipper Butterflies (Lepidoptera, Hesperiidae) along Elevational Gradients in Brazilian Atlantic Forest Reflects Vegetation Type Rather than Altitude

    Science.gov (United States)

    Carneiro, Eduardo; Mielke, Olaf Hermann Hendrik; Casagrande, Mirna Martins; Fiedler, Konrad

    2014-01-01

    Species turnover across elevational gradients has matured into an important paradigm of community ecology. Here, we tested whether ecological and phylogenetic structure of skipper butterfly assemblages is more strongly structured according to altitude or vegetation type along three elevation gradients of moderate extent in Serra do Mar, Southern Brazil. Skippers were surveyed along three different mountain transects, and data on altitude and vegetation type of every collection site were recorded. NMDS ordination plots were used to assess community turnover and the influence of phylogenetic distance between species on apparent community patterns. Ordinations based on ecological similarity (Bray-Curtis index) were compared to those based on phylogenetic distance measures (MPD and MNTD) derived from a supertree. In the absence of a well-resolved phylogeny, various branch length transformation methods were applied together with four different null models, aiming to assess if results were confounded by low-resolution trees. Species composition as well as phylogenetic community structure of skipper butterflies were more prominently related to vegetation type instead of altitude per se. Phylogenetic distances reflected spatial community patterns less clearly than species composition, but revealed a more distinct fauna of monocot feeders associated with grassland habitats, implying that historical factors have played a fundamental role in shaping species composition across elevation gradients. Phylogenetic structure of community turned out to be a relevant additional tool which was even superior to identify faunal contrasts between forest and grassland habitats related to deep evolutionary splits. Since endemic skippers tend to occur in grassland habitats in the Serra do Mar, inclusion of phylogenetic diversity may also be important for conservation decisions. PMID:25272004

  11. The influence of distinct types of aquatic vegetation on the flow field

    Science.gov (United States)

    Valyrakis, Manousos; Barcroft, Stephen; Yagci, Oral

    2014-05-01

    The Sustainable management of fluvial systems dealing with flood prevention, erosion protection and restoration of rivers and estuaries requires implementation of soft/green-engineering methods. In-stream aquatic vegetation can be regarded as one of these as it plays an important role for both river ecology (function) and geomorphology (form). The goal of this research is to offer insight gained from pilot experimental studies on the effects of a number of different elements modeling instream, aquatic vegetation on the local flow field. It is hypothesized that elements of the same effective "blockage" area but of distinct characteristics (structure, porosity and flexibility), will affect both the mean and fluctuating levels of the turbulent flow to a different degree. The above hypothesis is investigated through a set of rigorous set of experimental runs which are appropriately designed to assess the variability between the interaction of aquatic elements and flow, both quantitatively and qualitatively. In this investigation three elements are employed to model aquatic vegetation, namely a rigid cylinder, a porous but rigid structure and a flexible live plant (Cupressus Macrocarpa). Firstly, the flow field downstream each of the mentioned elements was measured under steady uniform flow conditions employing acoustic Doppler velocimetry. Three-dimensional flow velocities downstream the vegetation element are acquired along a measurement grid extending about five-fold the element's diameter. These measurements are analyzed to develop mean velocity and turbulent intensity profiles for all velocity components. A detailed comparison between the obtained results is demonstrative of the validity of the above hypothesis as each of the employed elements affects in a different manner and degree the flow field. Then a flow visualization technique, during which fluorescent dye is injected upstream of the element and images are captured for further analysis and comparison, was

  12. Woody plants diversity and type of vegetation in non cultivated plain of Moutourwa, Far-North, Cameroon

    Directory of Open Access Journals (Sweden)

    Gilbert Todou

    2016-12-01

    Full Text Available In order to valorize the wild vegetal resources for the efficient conservation and sustainable use in sahelo-sudanian zone in Cameroon, a study of non cultivated plain of Moutourwa was carry out to assess the floristic richness, the specific diversity and the type of vegetation. The inventory of all trees and shrubs (dbh ? 2.5 cm and the determination of the vegetation cover were done in five linear transects (20 m × 1000 m. In total, 27 families, 54 genera and 75 species were found. Caesalpinaceae is the most abundant family that relative abundance (pi*100 is 34.41%, the most abundant genus was Piliostigma (pi*100 = 30.66% and the most represented species was Piliostigma reticulatum (pi*100 = 29.56%; D = 53.6 stems/ha. The Simpson index (E= 0.89, the Shannon index (H= 3.2 and the equitability index of Pielou (J= 0.74 indicated that there were moderate diversity with more or less equitable species. The wild fruits species were numerous (pi*100 = 32.76%; D = 59.7 stems/ha. A. senegalensis is was the most represented (pi*100 = 9.04 ; D = 16.4 followed by Hexalobus monopetalus (pi*100 = 5.16 ; D = 9.4 and Balanites aegyptiaca (pi*100 = 3.69 ; D = 6.7. These results contribute efficaciously to valorize the wild vegetal resources for efficient conservation and sustainable use. Keywords: Woody plants diversity, conservation, sustainable use, sahelo-sudanian, Moutourwa

  13. Stratospheric ozone depletion during the 1995–1996 Arctic winter: 3-D simulations on the potential role of different PSC types

    Directory of Open Access Journals (Sweden)

    J. Hendricks

    Full Text Available The sensitivity of modelled ozone depletion in the winter Arctic stratosphere to different assumptions of prevalent PSC types and PSC formation mechanisms is investigated. Three-dimensional simulations of the winter 1995/96 are performed with the COlogne Model of the Middle Atmosphere (COMMA by applying different PSC microphysical schemes. Model runs are carried out considering either liquid or solid PSC particles or a combined microphysical scheme. These simulations are then compared to a model run which only takes into account binary sulfate aerosols. The results obtained with the three-dimensional model agree with trajectory-box simulations performed in previous studies. The simulations suggest that conditions appropriate for type Ia PSC existence (T < TNAT occur over longer periods and cover larger areas when compared to conditions of potential type Ib PSC existence. Significant differences in chlorine activation and ozone depletion occur between the simulations including only either liquid or solid PSC particles. The largest differences, occurring over large spatial scales and during prolonged time periods, are modelled first, when the stratospheric temperatures stay below TNAT , but above the threshold of effective liquid particle growth and second, in the case of the stratospheric temperatures remaining below this threshold, but not falling below the ice frost point. It can be generally concluded from the present study that differences in PSC microphysical schemes can cause significant fluctuations in ozone depletion modelled for the winter Arctic stratosphere.

    Key words. Atmospheric composition and structure (aerosols and particles; cloud physics and chemistry; middle atmosphere composition and chemistry

  14. Effect of alanine replacement of l17 and f19 on the aggregation and neurotoxicity of arctic-type aβ40.

    Directory of Open Access Journals (Sweden)

    Yi-Ru Chen

    Full Text Available Alzheimer's disease is the most common form of neurodegenerative disease. Beta-amyloid peptides (Aβ are responsible for neuronal death both in vitro and in vivo. Previously, L17 and F19 residues were identified as playing key roles in the stabilization of the Aβ40 conformation and in the reduction of its neurotoxicity. In this study, the effects of L17A/F19A mutations on the neurotoxicity of Aβ genetic mutant Arctic-type Aβ40(E22G were tested. The results showed that compared to Aβ40(E22G, Aβ40(L17A/F19A/E22G reduced the rate of conformation conversion, aggregation, and cytotoxicity, suggesting that L17 and F19 are critical residues responsible for conformational changes which may trigger the neurotoxic cascade of Aβ. Aβ40(L17A/F19A/E22G also had decreased damage due to reactive oxygen species. The results are consistent with the discordant helix hypothesis, and confirm that residues 17-25 are in the discordant helix region. Compared to Aβ40(L17A/F19A, reduction in aggregation of Aβ40(L17A/F19A/E22G was less significantly decreased. This observation provides an explanation based on the discordant helix hypothesis that the mutation of E22 to G22 of Aβ40(E22G alters the propensity of the discordant helix. Arctic-type Aβ40(E22G aggregates more severely than wild-type Aβ40, with a consequential increase in toxicity.

  15. Effects on the function of Arctic ecosystems in the short- and long-term perspectives.

    Science.gov (United States)

    Callaghan, Terry V; Björn, Lars Olof; Chernov, Yuri; Chapin, Terry; Christensen, Torben R; Huntley, Brian; Ims, Rolf A; Johansson, Margareta; Jolly, Dyanna; Jonasson, Sven; Matveyeva, Nadya; Panikov, Nicolai; Oechel, Walter; Shaver, Gus

    2004-11-01

    Historically, the function of Arctic ecosystems in terms of cycles of nutrients and carbon has led to low levels of primary production and exchanges of energy, water and greenhouse gases have led to low local and regional cooling. Sequestration of carbon from atmospheric CO2, in extensive, cold organic soils and the high albedo from low, snow-covered vegetation have had impacts on regional climate. However, many aspects of the functioning of Arctic ecosystems are sensitive to changes in climate and its impacts on biodiversity. The current Arctic climate results in slow rates of organic matter decomposition. Arctic ecosystems therefore tend to accumulate organic matter and elements despite low inputs. As a result, soil-available elements like nitrogen and phosphorus are key limitations to increases in carbon fixation and further biomass and organic matter accumulation. Climate warming is expected to increase carbon and element turnover, particularly in soils, which may lead to initial losses of elements but eventual, slow recovery. Individual species and species diversity have clear impacts on element inputs and retention in Arctic ecosystems. Effects of increased CO2 and UV-B on whole ecosystems, on the other hand, are likely to be small although effects on plant tissue chemisty, decomposition and nitrogen fixation may become important in the long-term. Cycling of carbon in trace gas form is mainly as CO2 and CH4. Most carbon loss is in the form of CO2, produced by both plants and soil biota. Carbon emissions as methane from wet and moist tundra ecosystems are about 5% of emissions as CO2 and are responsive to warming in the absence of any other changes. Winter processes and vegetation type also affect CH4 emissions as well as exchanges of energy between biosphere and atmosphere. Arctic ecosystems exhibit the largest seasonal changes in energy exchange of any terrestrial ecosystem because of the large changes in albedo from late winter, when snow reflects most

  16. 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...

  17. Effect of Different Vegetation Types on the Rhizosphere Soil Microbial Community Structure in the Loess Plateau of China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chao; LIU Guo-bin; XUE Sha; and XIAO Lie

    2013-01-01

    The Loess Plateau in China is one of the most eroded areas in the world. Accordingly, vegetation restoration has been implemented in this area over the past two decades to remedy the soil degradation problem. Understanding the microbial community structure is essential for the sustainability of ecosystems and for the reclamation of degraded arable land. This study aimed to determine the effect of different vegetation types on microbial processes and community structure in rhizosphere soils in the Loess Plateau. The six vegetation types were as follows:two natural grassland (Artemisia capillaries and Heteropappus altaicus), two artificial grassland (Astragalus adsurgens and Panicum virgatum), and two artificial shrubland (Caragana korshinskii and Hippophae rhamnoides) species. The microbial community structure and functional diversity were examined by analyzing the phospholipid fatty acids (PLFAs) and community-level physiological profiles. The results showed that rhizosphere soil sampled from the H. altaicus and A. capillaries plots had the highest values of microbial biomass C, average well color development of carbon resources, Gram-negative (G-) bacterial PLFA, bacterial PLFA, total PLFA, Shannon richness, and Shannon evenness, as well as the lowest metabolic quotient. Soil sampled from the H. rhamnoides plots had the highest metabolic quotient and Gram-positive (G+) bacterial PLFA, and soil sampled from the A. adsurgens and A. capillaries plots had the highest fungal PLFA and fungal:bacterial PLFA ratio. Correlation analysis indicated a signiifcant positive relationship among the microbial biomass C, G- bacterial PLFA, bacterial PLFA, and total PLFA. In conclusion, plant species under arid climatic conditions signiifcantly affected the microbial community structure in rhizosphere soil. Among the studied plants, natural grassland species generated the most favorable microbial conditions.

  18. Arctic Shipping

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Grønsedt, Peter; Lindstrøm Graversen, Christian

    , the latter aiming at developing key concepts and building up a basic industry knowledge base for further development of CBS Maritime research and teaching. This report attempts to map the opportunities and challenges for the maritime industry in an increasingly accessible Arctic Ocean...

  19. Fractal Characteristics of Soil Retention Curve and Particle Size Distribution with Different Vegetation Types in Mountain Areas of Northern China.

    Science.gov (United States)

    Niu, Xiang; Gao, Peng; Wang, Bing; Liu, Yu

    2015-12-03

    Based on fractal theory, the fractal characteristics of soil particle size distribution (PSD) and soil water retention curve (WRC) under the five vegetation types were studied in the mountainous land of Northern China. Results showed that: (1) the fractal parameters of soil PSD and soil WRC varied greatly under each different vegetation type, with Quercus acutissima Carr. and Robina pseudoacacia Linn. mixed plantation (QRM) > Pinus thunbergii Parl. and Pistacia chinensis Bunge mixed plantation (PPM) > Pinus thunbergii Parl. (PTP) > Juglans rigia Linn. (JRL) > abandoned grassland (ABG); (2) the soil fractal dimensions of woodlands (QRM, PPM, PTP and JRL) were significantly higher than that in ABG, and mixed forests (QRM and PPM) were higher than that in pure forests (PTP and JRL); (3) the fractal dimension of soil was positively correlated with the silt and clay content but negatively correlated with the sand content; and (4) the fractal dimension of soil PSD was positively correlated with the soil WRC. These indicated that the fractal parameters of soil PSD and soil WRC could act as quantitative indices to reflect the physical properties of the soil, and could be used to describe the influences of the Return Farmland to Forests Projects on soil structure.

  20. Influence of animal fat substitution by vegetal fat on Mortadella-type products formulated with different hydrocolloids

    Directory of Open Access Journals (Sweden)

    Erick Saldaña

    2015-12-01

    Full Text Available Meat has played a crucial role in human evolution and is an important component of a healthy and well-balanced diet on account of its nutritional properties, its high biological value as a source of protein, and the vitamins and minerals it supplies. We studied the effects of animal fat reduction and substitution by hydrogenated vegetal fat, sodium alginate and guar gum. Fatty acid composition, lipid oxidation, color and instrumental texture as well as the sensorial difference between low, substituted-fat and the traditional formulations for mortadella-type products were analyzed. Both substitution and reduction of animal fat decreased the saturated fatty acids percentage from 40% down to 31%. A texture profile analysis showed differences between the formulations. Furthermore, lipid oxidation values were not significant for treatments as regards the type and quantity of fat used while the use of sodium alginate and guar gum reduced the amounts of liquid released after cooking. Animal fat substitution does cause, however, a difference in overall sensorial perception compared with non-substituted products. The results confirm the viability of substituting vegetal fat for animal fat.

  1. Fractal Characteristics of Soil Retention Curve and Particle Size Distribution with Different Vegetation Types in Mountain Areas of Northern China

    Directory of Open Access Journals (Sweden)

    Xiang Niu

    2015-12-01

    Full Text Available Based on fractal theory, the fractal characteristics of soil particle size distribution (PSD and soil water retention curve (WRC under the five vegetation types were studied in the mountainous land of Northern China. Results showed that: (1 the fractal parameters of soil PSD and soil WRC varied greatly under each different vegetation type, with Quercus acutissima Carr. and Robina pseudoacacia Linn. mixed plantation (QRM > Pinus thunbergii Parl. and Pistacia chinensis Bunge mixed plantation (PPM > Pinus thunbergii Parl. (PTP > Juglans rigia Linn. (JRL > abandoned grassland (ABG; (2 the soil fractal dimensions of woodlands (QRM, PPM, PTP and JRL were significantly higher than that in ABG, and mixed forests (QRM and PPM were higher than that in pure forests (PTP and JRL; (3 the fractal dimension of soil was positively correlated with the silt and clay content but negatively correlated with the sand content; and (4 the fractal dimension of soil PSD was positively correlated with the soil WRC. These indicated that the fractal parameters of soil PSD and soil WRC could act as quantitative indices to reflect the physical properties of the soil, and could be used to describe the influences of the Return Farmland to Forests Projects on soil structure.

  2. Strategic metal deposits of the Arctic Zone

    Science.gov (United States)

    Bortnikov, N. S.; Lobanov, K. V.; Volkov, A. V.; Galyamov, A. L.; Vikent'ev, I. V.; Tarasov, N. N.; Distler, V. V.; Lalomov, A. V.; Aristov, V. V.; Murashov, K. Yu.; Chizhova, I. A.; Chefranov, R. M.

    2015-11-01

    Mineral commodities rank high in the economies of Arctic countries, and the status of mineral resources and the dynamics of their development are of great importance. The growing tendency to develop strategic metal resources in the Circumarctic Zone is outlined in a global perspective. The Russian Arctic Zone is the leading purveyor of these metals to domestic and foreign markets. The comparative analysis of tendencies in development of strategic metal resources of the Arctic Zone in Russia and other countries is crucial for the elaboration of trends of geological exploration and research engineering. This paper provides insight into the development of Arctic strategic metal resources in global perspective. It is shown that the mineral resource potential of the Arctic circumpolar metallogenic belt is primarily controlled by large and unique deposits of nonferrous, noble, and rare metals. The prospective types of economic strategic metal deposits in the Russian Arctic Zone are shown.

  3. Evaluation of sensor types and environmental controls on mapping biomass of coastal marsh emergent vegetation

    Science.gov (United States)

    Byrd, Kristin B.; O'Connell, Jessica L.; Di Tommaso, Stefania; Kelly, Maggi

    2014-01-01

    There is a need to quantify large-scale plant productivity in coastal marshes to understand marsh resilience to sea level rise, to help define eligibility for carbon offset credits, and to monitor impacts from land use, eutrophication and contamination. Remote monitoring of aboveground biomass of emergent wetland vegetation will help address this need. Differences in sensor spatial resolution, bandwidth, temporal frequency and cost constrain the accuracy of biomass maps produced for management applications. In addition the use of vegetation indices to map biomass may not be effective in wetlands due to confounding effects of water inundation on spectral reflectance. To address these challenges, we used partial least squares regression to select optimal spectral features in situ and with satellite reflectance data to develop predictive models of aboveground biomass for common emergent freshwater marsh species, Typha spp. and Schoenoplectus acutus, at two restored marshes in the Sacramento–San Joaquin River Delta, California, USA. We used field spectrometer data to test model errors associated with hyperspectral narrowbands and multispectral broadbands, the influence of water inundation on prediction accuracy, and the ability to develop species specific models. We used Hyperion data, Digital Globe World View-2 (WV-2) data, and Landsat 7 data to scale up the best statistical models of biomass. Field spectrometer-based models of the full dataset showed that narrowband reflectance data predicted biomass somewhat, though not significantly better than broadband reflectance data [R2 = 0.46 and percent normalized RMSE (%RMSE) = 16% for narrowband models]. However hyperspectral first derivative reflectance spectra best predicted biomass for plots where water levels were less than 15 cm (R2 = 0.69, %RMSE = 12.6%). In species-specific models, error rates differed by species (Typha spp.: %RMSE = 18.5%; S. acutus: %RMSE = 24.9%), likely due to the more vertical structure and

  4. Impacts of climate gradients on the vegetation phenology of major land use types in Central Asia (1981-2008)

    Institute of Scientific and Technical Information of China (English)

    Jahan KARIYEVA; Willem J.D.van LEEUWEN; Connie A.WOODHOUSE

    2012-01-01

    Time-series of land surface phenology (LSP)data offer insights about vegetation growth patterns.They can be generated by exploiting the temporal and spectral reflectance properties of land surface components.Interannual and seasonal LSP data are important for understanding and predicting an ecosystem's response to variations caused by natural and anthropogenic drivers.This research examines spatio-temporal change patterns and interactions between terrestrial phenology and 28 years of climate dynamics in Central Asia.Long-term (1981-2008) LSP records such as timing of the start,peak and length of the growing season and vegetation productivity were derived from remotely sensed vegetation greenness data.The patterns were analyzed to identify and characterize the impact of climate drivers at regional scales.We explored the relationships between phenological and precipitation and temperature variables for three generalized land use types that were exposed to decadelong regional drought events and intensified land and water resource use:rainfed agriculture,irrigated agriculture,and non-agriculture.To determine whether and how LSP dynamics are associated with climate patterns,a series of simple linear regression analyses between these two variables was executed.The three land use classes showed unique phenological responses to climate variation across Central Asia.Most of the phenological response variables were shown to be positively correlated to precipitation and negatively correlated to temperature.The most substantial climate variable affecting phenological responses of all three land use classes was a spring temperature regime.These results indicate that future higher temperatures would cause earlier and longer growing seasons.

  5. The impact of greenhouse vegetable farming duration and soil types on phytoavailability of heavy metals and their health risk in eastern China.

    Science.gov (United States)

    Yang, Lanqin; Huang, Biao; Hu, Wenyou; Chen, Yong; Mao, Mingcui; Yao, Lipeng

    2014-05-01

    Heavy metal contamination in vegetables from greenhouse vegetable production (GVP) in China requires major attention. For GVP sustainability at a large regional level, 441 surface GVP soil and 132 corresponding greenhouse vegetable samples were collected from six typical GVP bases in eastern China to systematically evaluate the impact of GVP duration and soil types (Anthrosols and Cambosols) on phytoavailability of four major metals, Cd, Cu, Zn, and Pb, and their health risk. The results revealed high Cd accumulation in leaf vegetables grown in Anthrosols, which might pose potential health risk. Regardless of soil types in the study region, greenhouse farming lowered soil pH and enhanced metal availability with rising GVP duration, which might exacerbate Cd phytoavailability and vegetable Cd contamination as well as potential health risk. Also, increased GVP soil organic matter contents over time, found in some locations, affected crop-depending Cu and Zn uptakes. Furthermore, due to GVP, the annual decrease rate of soil pH and increase rates of soil available metal concentrations were generally much greater in Anthrosols than those in Cambosols, which contributed a lot to high Cd uptake by leaf vegetables grown in Anthrosols and their potential health risk. From sustainable GVP perspective, fertilization strategy with reduced frequency and rate is especially important and effective for abating soil and vegetable contamination by heavy metals under greenhouse farming.

  6. Tidal saline wetland regeneration of sentinel vegetation types in the Northern Gulf of Mexico: An overview

    Science.gov (United States)

    Jones, Scott F.; Stagg, Camille L.; Krauss, Ken W.; Hester, Mark W.

    2016-06-01

    Tidal saline wetlands in the Northern Gulf of Mexico (NGoM) are dynamic and frequently disturbed systems that provide myriad ecosystem services. For these services to be sustained, dominant macrophytes must continuously recolonize and establish after disturbance. Macrophytes accomplish this regeneration through combinations of vegetative propagation and sexual reproduction, the relative importance of which varies by species. Concurrently, tidal saline wetland systems experience both anthropogenic and natural hydrologic alterations, such as levee construction, sea-level rise, storm impacts, and restoration activities. These hydrologic alterations can affect the success of plant regeneration, leading to large-scale, variable changes in ecosystem structure and function. This review describes the specific regeneration requirements of four dominant coastal wetland macrophytes along the NGoM (Spartina alterniflora, Avicennia germinans, Juncus roemerianus, and Batis maritima) and compares them with current hydrologic alterations to provide insights into potential future changes in dominant ecosystem structure and function and to highlight knowledge gaps in the current literature that need to be addressed.

  7. Tidal saline wetland regeneration of sentinel vegetation types in the Northern Gulf of Mexico: An overview

    Science.gov (United States)

    Jones, Scott F; Stagg, Camille L.; Krauss, Ken W.; Hester, Mark W.

    2016-01-01

    Tidal saline wetlands in the Northern Gulf of Mexico (NGoM) are dynamic and frequently disturbed systems that provide myriad ecosystem services. For these services to be sustained, dominant macrophytes must continuously recolonize and establish after disturbance. Macrophytes accomplish this regeneration through combinations of vegetative propagation and sexual reproduction, the relative importance of which varies by species. Concurrently, tidal saline wetland systems experience both anthropogenic and natural hydrologic alterations, such as levee construction, sea-level rise, storm impacts, and restoration activities. These hydrologic alterations can affect the success of plant regeneration, leading to large-scale, variable changes in ecosystem structure and function. This review describes the specific regeneration requirements of four dominant coastal wetland macrophytes along the NGoM (Spartina alterniflora, Avicennia germinans, Juncus roemerianus, and Batis maritima) and compares them with current hydrologic alterations to provide insights into potential future changes in dominant ecosystem structure and function and to highlight knowledge gaps in the current literature that need to be addressed.

  8. Arctic Diatoms

    DEFF Research Database (Denmark)

    Tammilehto, Anna

    are often dominated by diatoms. They are single-celled, eukaryotic algae, which play an essential role in ocean carbon and silica cycles. Many species of the diatom genus Pseudo-nitzschia Peragallo produce a neurotoxin, domoic acid (DA), which can be transferred to higher levels in food webs causing amnesic...... as vectors for DA to higher levels in the arctic marine food web, posing a possible risk also to humans. DA production in P. seriata was, for the first time, found to be induced by chemical cues from C. finmarchicus, C. hyperboreus and copepodite stages C3 and C4, suggesting that DA may be related to defense...... against grazing. This thesis also quantified population genetic composition and changes of the diatom Fragilariopsis cylindrus spring bloom using microsatellite markers. Diatom-dominated spring blooms in the Arctic are the key event of the year, providing the food web with fundamental pulses of organic...

  9. Arctic Ocean

    Science.gov (United States)

    Parkinson, Claire L.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The Arctic Ocean is the smallest of the Earth's four major oceans, covering 14x10(exp 6) sq km located entirely within the Arctic Circle (66 deg 33 min N). It is a major player in the climate of the north polar region and has a variable sea ice cover that tends to increase its sensitivity to climate change. Its temperature, salinity, and ice cover have all undergone changes in the past several decades, although it is uncertain whether these predominantly reflect long-term trends, oscillations within the system, or natural variability. Major changes include a warming and expansion of the Atlantic layer, at depths of 200-900 m, a warming of the upper ocean in the Beaufort Sea, a considerable thinning (perhaps as high as 40%) of the sea ice cover, a lesser and uneven retreat of the ice cover (averaging approximately 3% per decade), and a mixed pattern of salinity increases and decreases.

  10. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    Science.gov (United States)

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica land was the most obvious among them, with soil pH increasing by 0.43. The effects of fertilization and vegetation type on pH and exchangeable acidity decreased with the

  11. Arctic Social Sciences: Opportunities in Arctic Research.

    Science.gov (United States)

    Arctic Research Consortium of the United States, Fairbanks, AK.

    The U.S. Congress passed the Arctic Research and Policy Act in 1984 and designated the National Science Foundation (NSF) the lead agency in implementing arctic research policy. In 1989, the parameters of arctic social science research were outlined, emphasizing three themes: human-environment interactions, community viability, and rapid social…

  12. Litter flammability of French Mediterranean vegetation types : a cross-substratum analysis

    OpenAIRE

    Curt, T.; Schaffhauser, A.; Borgniet, L.; Esteve, R.; Ganteaume, A.; Jappiot, M.; Lampin-Maillet, C.; Martin, W.; N'Diaye, A

    2010-01-01

    International audience; Assessing the flammability of litters in fire-prone ecosystems of major importance to quantify the wildland fire hazard. We compared undisturbed litter samples typical of French ecosystems on the two main types of substratum, i.e. acidic versus limestone, to investigate to which extent their characteristics and flammability may differ. We measured in the laboratory several flammability parameters on oven-dried samples that mimic the high fire hazard level in summer. On...

  13. [Consumption of nuts and vegetal oil in people with type 1 diabetes mellitus].

    Science.gov (United States)

    Ferrer-García, Juan Carlos; Granell Vidal, Lina; Muñoz Izquierdo, Amparo; Sánchez Juan, Carlos

    2015-06-01

    Introducción: estudios recientes han demostrado los beneficios cardiovasculares de la dieta mediterránea enriquecida con aceite de oliva y frutos secos. Las personas con diabetes, que tienen un mayor riesgo de complicaciones cardiovasculares, podrían beneficiarse en gran medida de seguir ese tipo de patrón alimentario. Objetivos: análisis de la ingesta de grasas vegetales procedentes de frutos secos y aceites vegetales en pacientes con diabetes mellitus tipo 1 (DM1). Métodos: estudio transversal descriptivo que compara 60 personas con DM1 y 60 sujetos sanos. Se recoge la frecuencia de consumo de aceites vegetales y de frutos secos y se calcula el aporte procedente de estos alimentos en ácidos grasos mono y poliinsaturados (ácido oleico, linoleico y -linolénico). Se utilizó un cuestionario de frecuencia de consumo diseñado de forma específica. Se recogen variables antropométricas, factores de riesgo cardiovascular y variables relacionadas con la diabetes. Resultados: el consumo total de grasa vegetal procedente de aceites vegetales fue similar en los pacientes con DM1 frente a los sujetos control (3,02 ± 1,14 vs. 3,07 ± 1,27 Raciones (R)/día, P = 0,822) y de frutos secos (1,35 ± 2,24 vs. 1,60 ± 2,44 R/semana, P = 0,560). El grupo DM1 consumió menos aceite de oliva que el grupo control (2,55 ± 1,17 vs. 3,02 ± 1,34 R/día, P = 0,046). Se detectó un menor consumo de ácido -linolénico respecto al grupo control (1,13 ± 2,06 vs. 2,64 ± 4,37 g/día, P = 0,018), mientras que no hubo diferencias en el resto de ácidos grasos (oleico 28,30 ± 18,13 vs. 29,53 ± 16,90 g/día, P = 0,703; linoleico 13,70 ± 16,80 vs. 15,45 ± 19,90 g/día, P = 0,605). En los DM1 no se demostró una influencia del consumo de las grasas vegetales procedentes de aceites y frutos secos en los parámetros antropométricos, metabólicos y variables específicas de la diabetes. Conclusiones: en las personas con DM1 el consumo total de aceites vegetales y frutos secos no

  14. Arctic Change Information for a Broad Audience

    Science.gov (United States)

    Soreide, N. N.; Overland, J. E.; Calder, J.

    2002-12-01

    Demonstrable environmental changes have occurred in the Arctic over the past three decades. NOAA's Arctic Theme Page is a rich resource web site focused on high latitude studies and the Arctic, with links to widely distributed data and information focused on the Arctic. Included is a collection of essays on relevant topics by experts in Arctic research. The website has proven useful to a wide audience, including scientists, students, teachers, decision makers and the general public, as indicated through recognition by USA Today, Science magazine, etc. (http://www.arctic.noaa.gov) Working jointly with NSF and the University of Washington's Polar Science Center as part of the Study of Environmental Arctic Change (SEARCH) program, NOAA has developed a website for access to pan-Arctic time series spanning diverse data types including climate indices, atmospheric, oceanic, sea ice, terrestrial, biological and fisheries. Modest analysis functions and more detailed analysis results are provided. (http://www.unaami.noaa.gov/). This paper will describe development of an Artic Change Detection status website to provide a direct and comprehensive view of previous and ongoing change in the Arctic for a broad climate community. For example, composite metrics are developed using principal component analysis based on 86 multivariate pan-Arctic time series for seven data types. Two of these metrics can be interpreted as a regime change/trend component and an interdecadal component. Changes can also be visually observed through tracking of 28 separate biophysical indicators. Results will be presented in the form of a web site with relevant, easily understood, value-added knowledge backed by peer review from Arctic scientists and scientific journals.

  15. Vegetation type modifies the cycling and aromaticity of DOC and N in small-scale urban stormwater basins

    Science.gov (United States)

    Nocco, M. A.; Dolliver, H.; Balster, N. J.

    2012-12-01

    Urban land use can cause ecological degradation of surface waters through stormwater inputs of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN). Green infrastructure practices such as small-scale (m2) vegetated stormwater basins (e.g. bioretention basins, rain gardens, bioswales) have been implemented for the past 20 years to reduce stormwater quantity and improve water quality in urban ecosystems. Although the efficacy of these practices rests on an ecological assumption that plant-soil interactions will alter the C and N cycles relative to surrounding urban infrastructure, the impact of vegetation type on the biogeochemistry of urban stormwater basins is not well understood. We hypothesized that the two most prevalent types of vegetation planted in stormwater basins in the Midwestern United States, native prairie and woody shrubs, differ in their cycling and export of C and N due to differences in relative woody and parenchymatic tissue inputs to soil organic matter, root morphology, and root exudation. We tested this hypothesis in an open-air field laboratory consisting of 9 vegetated mesocosms (3 native prairie, 3 woody shrub, 3 bare soil) designed in 2005 according to WI-DNR specifications for residential stormwater basin construction. During precipitation events in July-October 2011, we collected stormwater runoff from an adjacent tin roof (417 m2) and conducted 9 runoff applications that mimicked the rate and intensity of runoff that would be received by a small-scale (5.9 m2) stormwater basin in the urban environment during a 2.54 cm rain event. We instrumented each mesocosm to quantify (1) first flush and peak flow concentration of DOC and TDN during gravitational soil water flux (2) DOC and TDN concentration in soil pore space after gravitational water flux ceased, and (3) SUVA254 as an optical proxy for aromaticity in the first flush and peak flow of gravitational soil water flux. Results show significant differences (psoil. The DOC

  16. Projected Impacts of 21st Century Climate Change on Potential Habitat for Vegetation and Forest Types in Russia

    Science.gov (United States)

    Soja, A. J.; Tchebakova, N. M.; Parfenova, E. I.; Cantin, A.; Conard, S. G.

    2015-12-01

    Global GCMs have demonstrated profound potential for projections to affect the distribution of terrestrial ecosystems and individual species at all hierarchical levels. We modeled progression of potential Russian ecotones and forest-forming species as the climate changes. Large-scale bioclimatic models were developed to predict Russian zonal vegetation (RuBCliM) and forest types (ForCliM) from three bioclimatic indices (1) growing degree-days above 5 degrees C; (2) negative degree-days below 0 C ; and (3) an annual moisture index (ratio of growing degree days to annual precipitation). The presence or absence of continuous permafrost was explicitly included in the models as limiting the forests and tree species distribution. All simulations to predict vegetation change across Russia were run by coupling our bioclimatic models with bioclimatic indices and the permafrost distribution for the baseline period and for the future 2020, 2050 and 2100 simulated by 3 GCMs (CGCM3.1, HadCM3 and IPSLCM4) and 3 climate change scenarios (A1B, A2 and B1). Under these climate scenarios, it is projected the zonobiomes will shift far northward to reach equilibrium with the change in climate. Under the warmer and drier projected future climate, about half of Russia would be suitable for the forest-steppe ecotone and grasslands, rather than for forests. Water stress tolerant light-needled taiga would have an increased advantage over water-loving dark-needled taiga. Permafrost-tolerant L. dahurica taiga would remain the dominant forest across permafrost. Increases in severe fire weather would lead to increases in large, high-severity fires, especially at boundaries between forest ecotones, which can be expected to facilitate a more rapid progression of vegetation towards a new equilibrium with the climate. Adaptation to climate change may be facilitated by: assisting migration of forests by seed transfers to establish genotypes that may be more ecologically suited as climate changes

  17. Latent heat exchange in the boreal and arctic biomes.

    Science.gov (United States)

    Kasurinen, Ville; Alfredsen, Knut; Kolari, Pasi; Mammarella, Ivan; Alekseychik, Pavel; Rinne, Janne; Vesala, Timo; Bernier, Pierre; Boike, Julia; Langer, Moritz; Belelli Marchesini, Luca; van Huissteden, Ko; Dolman, Han; Sachs, Torsten; Ohta, Takeshi; Varlagin, Andrej; Rocha, Adrian; Arain, Altaf; Oechel, Walter; Lund, Magnus; Grelle, Achim; Lindroth, Anders; Black, Andy; Aurela, Mika; Laurila, Tuomas; Lohila, Annalea; Berninger, Frank

    2014-11-01

    In this study latent heat flux (λE) measurements made at 65 boreal and arctic eddy-covariance (EC) sites were analyses by using the Penman-Monteith equation. Sites were stratified into nine different ecosystem types: harvested and burnt forest areas, pine forests, spruce or fir forests, Douglas-fir forests, broadleaf deciduous forests, larch forests, wetlands, tundra and natural grasslands. The Penman-Monteith equation was calibrated with variable surface resistances against half-hourly eddy-covariance data and clear differences between ecosystem types were observed. Based on the modeled behavior of surface and aerodynamic resistances, surface resistance tightly control λE in most mature forests, while it had less importance in ecosystems having shorter vegetation like young or recently harvested forests, grasslands, wetlands and tundra. The parameters of the Penman-Monteith equation were clearly different for winter and summer conditions, indicating that phenological effects on surface resistance are important. We also compared the simulated λE of different ecosystem types under meteorological conditions at one site. Values of λE varied between 15% and 38% of the net radiation in the simulations with mean ecosystem parameters. In general, the simulations suggest that λE is higher from forested ecosystems than from grasslands, wetlands or tundra-type ecosystems. Forests showed usually a tighter stomatal control of λE as indicated by a pronounced sensitivity of surface resistance to atmospheric vapor pressure deficit. Nevertheless, the surface resistance of forests was lower than for open vegetation types including wetlands. Tundra and wetlands had higher surface resistances, which were less sensitive to vapor pressure deficits. The results indicate that the variation in surface resistance within and between different vegetation types might play a significant role in energy exchange between terrestrial ecosystems and atmosphere. These results suggest the need

  18. Nitrogen–use efficiency in different vegetation type at Cikaniki Research Station, Halimun-Salak Mountain National Park, West Java

    Directory of Open Access Journals (Sweden)

    SUHARNO

    2007-10-01

    Full Text Available A research about nitrogen–use efficiency (NUE and trees identification was conducted at different vegetation type at Cikaniki, Halimun-Salak National Park, West Java. Plot quadrate methods (20 x 50 m was used to analyze trees vegetation and Kjeldahl methods was used to analyze leaf nitrogen. The width and length of the leaf was also measured to obtain the leaf surface area. The result showed that there are 61 individual trees which consisted of 24 species was identified. The species which have 5 highest important value are Altingia excelsa (64,657, Castanopsis javanica (39,698, Platea latifolia (27,684, Garcinia rostrata (21,151, and Schima walichii (16,049. Futhermore Eugenia lineata (13,967, Melanochyla caesa (12,241, Quercus lineata (10,766, platea excelsa (10,766 have lower important value. Other trees have important value less than 10. Morphological and nitrogen content analyze were done on 4 species : Quercus lineata, G. rostrata, A. excelsa, and E. lineata. Among them, Quercus lineata has highest specific leaf area (SLA (0,01153, followed by G. rostrata (0,00821, A. excelsa (0,00579, and E. lineata (0,00984 g/cm2. The highest number of stomata was found on A. excelsa (85,10/mm2, followed by E. lineata (74,40/mm2, Q. lineata (53,70/mm2, and G. rostrata (18,4 /mm2. The emergent species (A. excelsa and Q. lineata have higher nitrogen content than the underlayer species (G. rostrata and E. lineata. A. excelsa have highest nitrogen use efficiency (28,19% compare to E. lineata (23,81% , Q. lineata (19,09%, and G. rostrata (14,87%. Although not significant, emergen species have higher NUE than underlayer species.

  19. Spatial-seasonal variation of soil denitrification under three riparian vegetation types around the Dianchi Lake in Yunnan, China.

    Science.gov (United States)

    Wang, Shaojun; Cao, Zilin; Li, Xiaoying; Liao, Zhouyu; Hu, Binghui; Ni, Jie; Ruan, Honghua

    2013-05-01

    Outbreaks of nuisance cyanobacterial bloom are predicted to occur frequently under the effect of severe eutrophication in the water body of Lake Dianchi since the 1990s. Riparian buffers are now well recognized for their roles in the removal of inorganic nitrogen mainly via denitrification. Little is known, however, about the mechanisms of nitrate removal in the riparian buffers of Lake Dianchi. We investigated the wet and dry seasonal dynamics of denitrification rate (DNR) in the soil profiles along the topographic gradient in three riparian buffers with different vegetation types (i.e. forest, open forest, and grass). A strong vertical pattern was observed in soil organic C and N concentrations (i.e. total N, DON, NO3-N, and NH4-N) along the soil layers. We also found significantly higher in situ denitrification activity in the upper horizon along each topohydrosequence while the activities of soil denitrification could be detected down to deeper soil horizons (0.1 to 0.8 mg N per kg dry soil per day), which may contribute significantly to the reduction of the ground water nitrate. Meanwhile, the DNR in the zones near the lake was significantly higher than that in zones near the border with the upland terrace, and also in the wet seasons than in dry seasons. Denitrification rates in the forest, open forest and grass sites were significantly different only in wet seasons. Especially, we found soil organic C had a strong correlation with denitrification in all sites, despite the large intersite variability of soil and vegetation. Our data suggested spatial heterogeneity of substrate availability along a hydrologic and topographic gradient can be the primary control on spatial-seasonal patterns of denitrification in riparian buffers.

  20. Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes

    Directory of Open Access Journals (Sweden)

    M. Bahn

    2009-12-01

    Full Text Available Soil respiration (SR constitutes the largest flux of CO2 from terrestrial ecosystems to the atmosphere. There still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 72 site-years for 58 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SR MAT, irrespective of the type of ecosystem and biome. This convergence is to be theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q10. We further show that for seasonally dry sites where annual precipitation (P is lower than potential evapotranspiration (PET, annual SR can be predicted from wet season SR MAT corrected for a factor related to P/PET. Our finding indicates that it is sufficient to measure SR MAT for obtaining a highly constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution and interannual variation of soil CO2 emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatio-temporal resolution of a major component of the global carbon cycle.

  1. Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes

    Directory of Open Access Journals (Sweden)

    M. Bahn

    2010-07-01

    Full Text Available Soil respiration (SR constitutes the largest flux of CO2 from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SRMAT, irrespective of the type of ecosystem and biome. This is theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q10. We further show that for seasonally dry sites where annual precipitation (P is lower than potential evapotranspiration (PET, annual SR can be predicted from wet season SRMAT corrected for a factor related to P/PET. Our finding indicates that it can be sufficient to measure SRMAT for obtaining a well constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution of soil CO2 emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatial resolution of a major component of the global carbon cycle.

  2. Sensitivity of Coastal Environments and Wildlife to Spilled Oil: Northwest Arctic, Alaska: ESI (Environmental Sensitivity Index Shoreline Types - Polygons and Lines)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing the shoreline and coastal habitats of Northwest Arctic, Alaska classified according to the...

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

    Science.gov (United States)

    Nosevich, Ekaterina; Anisimov, Michail; Sapelko, Tatyana

    2015-04-01

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

  4. Growth potential of Salmonella spp. and Listeria monocytogenes in nine types of ready-to-eat vegetables stored at variable temperature conditions during shelf-life.

    Science.gov (United States)

    Sant'Ana, Anderson S; Barbosa, Matheus S; Destro, Maria Teresa; Landgraf, Mariza; Franco, Bernadette D G M

    2012-06-15

    Growth potential (δ) is defined as the difference between the population of a microorganism at the end of shelf-life of specific food and its initial population. The determination of δ of Salmonella and Listeria monocytogenes in RTE vegetables can be very useful to determine likely threats to food safety. However, little is known on the behavior of these microorganisms in several RTE vegetables. Therefore, the aim of this study was to determine the δ of both pathogens in nine different types of RTE vegetables (escarole, collard green, spinach, watercress, arugula, grated carrot, green salad, and mix for yakisoba) stored at refrigeration (7°C) and abuse temperature (15°C). The population of aerobic microorganisms and lactic acid bacteria, including those showing antimicrobial activity has been also determined. Results indicated that L. monocytogenes was able to grow (δ≥0.5 log(10)) in more storage conditions and vegetables than Salmonella. Both microorganisms were inhibited in carrots, although a more pronounced effect has been observed against L. monocytogenes. The highest δ values were obtained when the RTE vegetables were stored 15°C/6days in collard greens (δ=3.3) and arugula (δ=3.2) (L. monocytogenes) and arugula (δ=4.1) and escarole (δ=2.8) (Salmonella). In most vegetables and storage conditions studied, the counts of total aerobic microorganisms raised significantly independent of the temperature of storage (p<0.05). Counts of lactic acid bacteria were higher in vegetables partially or fully stored at abuse temperature with recovery of isolates showing antimicrobial activity. In conclusion, the results of this study show that Salmonella and L. monocytogenes may grow and reach high populations in RTE vegetables depending on storage conditions and the definition of effective intervention strategies are needed to control their growth in these products.

  5. Differences in Fine-Root Biomass of Trees and Understory Vegetation among Stand Types in Subtropical Forests.

    Science.gov (United States)

    Fu, Xiaoli; Wang, Jianlei; Di, Yuebao; Wang, Huimin

    2015-01-01

    Variation of total fine-root biomass among types of tree stands has previously been attributed to the characteristics of the stand layers. The effects of the understory vegetation on total fine-root biomass are less well studied. We examined the variation of total fine-root biomass in subtropical tree stands at two sites of Datian and Huitong in China. The two sites have similar humid monsoon climate but different soil organic carbon. One examination compared two categories of basal areas (high vs. low basal area) in stands of single species. A second examination compared single-species and mixed stands with comparable basal areas. Low basal area did not correlate with low total fine-root biomass in the single-species stands. The increase in seedling density but decrease in stem density for the low basal area stands at Datian and the quite similar stand structures for the basal-area contrast at Huitong helped in the lack of association between basal area and total fine-root biomass at the two sites, respectively. The mixed stands also did not yield higher total fine-root biomasses. In addition to the lack of niche complementarity between tree species, the differences in stem and seedling densities and the belowground competition between the tree and non-tree species also contributed to the similarity of the total fine-root biomasses in the mixed and single-species stands. Across stand types, the more fertile site Datian yielded higher tree, non-tree and total fine-root biomasses than Huitong. However, the contribution of non-tree fine-root biomass to the total fine-root biomass was higher at Huitong (29.4%) than that at Datian (16.7%). This study suggests that the variation of total fine-root biomass across stand types not only was associated with the characteristics of trees, but also may be highly dependent on the understory layer.

  6. Differences in Fine-Root Biomass of Trees and Understory Vegetation among Stand Types in Subtropical Forests.

    Directory of Open Access Journals (Sweden)

    Xiaoli Fu

    Full Text Available Variation of total fine-root biomass among types of tree stands has previously been attributed to the characteristics of the stand layers. The effects of the understory vegetation on total fine-root biomass are less well studied. We examined the variation of total fine-root biomass in subtropical tree stands at two sites of Datian and Huitong in China. The two sites have similar humid monsoon climate but different soil organic carbon. One examination compared two categories of basal areas (high vs. low basal area in stands of single species. A second examination compared single-species and mixed stands with comparable basal areas. Low basal area did not correlate with low total fine-root biomass in the single-species stands. The increase in seedling density but decrease in stem density for the low basal area stands at Datian and the quite similar stand structures for the basal-area contrast at Huitong helped in the lack of association between basal area and total fine-root biomass at the two sites, respectively. The mixed stands also did not yield higher total fine-root biomasses. In addition to the lack of niche complementarity between tree species, the differences in stem and seedling densities and the belowground competition between the tree and non-tree species also contributed to the similarity of the total fine-root biomasses in the mixed and single-species stands. Across stand types, the more fertile site Datian yielded higher tree, non-tree and total fine-root biomasses than Huitong. However, the contribution of non-tree fine-root biomass to the total fine-root biomass was higher at Huitong (29.4% than that at Datian (16.7%. This study suggests that the variation of total fine-root biomass across stand types not only was associated with the characteristics of trees, but also may be highly dependent on the understory layer.

  7. A high-performance ground-based prototype of horn-type sequential vegetable production facility for life support system in space

    Science.gov (United States)

    Fu, Yuming; Liu, Hui; Shao, Lingzhi; Wang, Minjuan; Berkovich, Yu A.; Erokhin, A. N.; Liu, Hong

    2013-07-01

    Vegetable cultivation plays a crucial role in dietary supplements and psychosocial benefits of the crew during manned space flight. Here we developed a ground-based prototype of horn-type sequential vegetable production facility, named Horn-type Producer (HTP), which was capable of simulating the microgravity effect and the continuous cultivation of leaf-vegetables on root modules. The growth chamber of the facility had a volume of 0.12 m3, characterized by a three-stage space expansion with plant growth. The planting surface of 0.154 m2 was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate. Root modules were fastened to a central porous tube supplying water, and moved forward with plant growth. The total illuminated crop area of 0.567 m2 was provided by a combination of red and white light emitting diodes on the internal surfaces. In tests with a 24-h photoperiod, the productivity of the HTP at 0.3 kW for lettuce achieved 254.3 g eatable biomass per week. Long-term operation of the HTP did not alter vegetable nutrition composition to any great extent. Furthermore, the efficiency of the HTP, based on the Q-criterion, was 7 × 10-4 g2 m-3 J-1. These results show that the HTP exhibited high productivity, stable quality, and good efficiency in the process of planting lettuce, indicative of an interesting design for space vegetable production.

  8. 广西植被类型及其分类系统%Types of Vegetation and Its Classified System in Guangxi

    Institute of Scientific and Technical Information of China (English)

    温远光; 严理; 李治基; 李信贤; 朱宏光; 梁宏温; 和太平; 庄嘉; 罗应华; 吴庆标

    2014-01-01

    [Objective]Vegetation is the most sensitive factor of the local natural biogeography on the Earth,and play an important role in maintaining human being sustainable development and mitigating climate change.The obj ective of this paper was to introtduce systematically the types of vegetation in Guangxi and its classified system and to provide basic data for protection, research and uses of the vegetation.[Methods]Based on the classification principle,unit and sys-tem of China vegetation,the data that included both publications recording the types of Guan-gxi vegetations and authors'vegetation investigation in Guangxi since 1950 were gathered and sorted out.And then two classification systems were drawn up for natural and artificial vegeta-tions of Guangxi.[Results]The natural vegetation in Guangxi could be divided into 4 classes of vegetation type,26 groups of vegetation type,and 722 formations.The artificial vegetation in Guangxi could be divided into 5 vegetation types, 20 vegetation subtypes, and 298 formations.Among 722 formations of natural vegetation,the type numbers of forest,bamboo forest,shrub,herb and hydrovegetation account for 63%,4%,10%,6% and 17%,respectively. Among 2 9 8 formations of artificial vegetation, the type numbers of timber forest,economic frult and tree forest,urban forest vegetation,crop vegetation and artificial paludal and hydric vegetation account for 28%,20%,29%,17% and 6%,respectively.[Conclusion]Guangxi is one of the most rich regions of vegetation types in China with 1020 formations,and has an impor-tant position in the protection,research and uses of vegetation in China.%【目的】植被是地球上最为敏感的自然地理环境要素,在减缓气候变化和实现人类可持续发展中具有无法替代的作用。本文全面、系统地介绍广西植被类型及其分类系统,为植被保护、研究和利用提供基础资料。【方法】通过对已发表记载有广西植被类型以及作者近60年来对广西

  9. The soil carbon/nitrogen ratio and moisture affect microbial community structures in alkaline permafrost-affected soils with different vegetation types on the Tibetan plateau.

    Science.gov (United States)

    Zhang, Xinfang; Xu, Shijian; Li, Changming; Zhao, Lin; Feng, Huyuan; Yue, Guangyang; Ren, Zhengwei; Cheng, Guogdong

    2014-01-01

    In the Tibetan permafrost region, vegetation types and soil properties have been affected by permafrost degradation, but little is known about the corresponding patterns of their soil microbial communities. Thus, we analyzed the effects of vegetation types and their covariant soil properties on bacterial and fungal community structure and membership and bacterial community-level physiological patterns. Pyrosequencing and Biolog EcoPlates were used to analyze 19 permafrost-affected soil samples from four principal vegetation types: swamp meadow (SM), meadow (M), steppe (S) and desert steppe (DS). Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria dominated bacterial communities and the main fungal phyla were Ascomycota, Basidiomycota and Mucoromycotina. The ratios of Proteobacteria/Acidobacteria decreased in the order: SM>M>S>DS, whereas the Ascomycota/Basidiomycota ratios increased. The distributions of carbon and nitrogen cycling bacterial genera detected were related to soil properties. The bacterial communities in SM/M soils degraded amines/amino acids very rapidly, while polymers were degraded rapidly by S/DS communities. UniFrac analysis of bacterial communities detected differences among vegetation types. The fungal UniFrac community patterns of SM differed from the others. Redundancy analysis showed that the carbon/nitrogen ratio had the main effect on bacteria community structures and their diversity in alkaline soil, whereas soil moisture was mainly responsible for structuring fungal communities. Thus, microbial communities and their functioning are probably affected by soil environmental change in response to permafrost degradation.

  10. Unmanned Platforms Monitor the Arctic Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    de Boer, Gijs; Ivey, Mark D.; Schmid, Beat; McFarlane, Sally A.; Petty, Rickey C.

    2016-02-22

    In the Arctic, drones and tethered balloons can make crucial atmospheric measurement to provide a unique perspective on an environment particularly vulnerable to climate change. Climate is rapidly changing all over the globe, but nowhere is that change faster than in the Arctic. The evidence from recent years is clear: Reductions in sea ice (Kwok and Unstersteiner, 2011) and permafrost (Romanovsky et al., 2002), in addition to modification of the terriestrial ecosystem through melting permafrost and shifting vegetation zones (burek et al., 2008; Sturm, et al., 2001), all point to a rapidly evolving.

  11. Soil Organic Carbon and Its Fractions Across Vegetation Types: Effects of Soil Mineral Surface Area and Microaggregates

    Institute of Scientific and Technical Information of China (English)

    WU Qing-Biao; WANG Xiao-Ke; OUYANG Zhi-Yun

    2009-01-01

    Soil organic carbon (SOC) can act as a sink or source of atmospheric carbon dioxide;therefore,it is important to understand the amount and composition of SOC in terrestrial ecosystems,the spatial variation in SOC,and the underlying mechanisms that stabilize SOC.In this study,density fractionation and acid hydrolysis were used to assess the spatial variation in SOC,the heavy fraction of organic carbon (HFOC),and the resistant organic carbon (ROC) in soils of the southern Hulun Buir region,northeastern China,and to identify the major factors that contribute to this variation.The results showed that as the contents of clay and silt particles (0-50 μm) increased,both methylene blue (MB) adsorption by soil minerals and microaggregate contents increased in the 0-20 and 20-40 cm soil layers (P<0.05).Although varying with vegetation types,SOC,HFOC,and ROC contents increased significantly with the content of clay and silt particles,MB adsorption by soil minerals,and microaggregate content (P<0.05),suggesting that soil texture,the MB adsorption by soil minerals,and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulun Buir region.

  12. Effect of oil type and fatty acid composition on dynamic and steady shear rheology of vegetable oils.

    Science.gov (United States)

    Yalcin, Hasan; Toker, Omer Said; Dogan, Mahmut

    2012-01-01

    In this study, effect of fatty acid composition on dynamic and steady shear rheology of oils was studied. For this aim, different types of vegetable oils (soybean, sunflower, olive, hazelnut, cottonseed and canola), were used. Rheological properties of oil samples were identified by rheometer (Thermo-Haake) at 25°C and fatty acid composition of oils was determined by GC (Agilent 6890). Steady shear rheological properties of oil samples were measured at shear rate range of 0.1-100 s⁻¹. Viscosity of olive, hazelnut, cottonseed, canola, soybean and sunflower was 61.2 mPa.s, 59.7 mPa.s, 57.3 mPa.s, 53.5 mPa.s, 48.7 mPa.s and 48.2 mPa.s, respectively. There was a significant difference between viscosity of oils except soybean and sunflower. As a result it was seen that there was a correlation between viscosity and monounsaturated (R=0.89), polyunsaturated (R=-0.97) fatty acid composition of oils, separately. Equation was found to predict viscosity of the oils based on mono and polyunsaturation composition of oils. In addition the dynamic rheological properties of oils were also examined. G', G'' and tan δ (G''/G') values were measured at 0.3 Pa (in viscoelastic region) and 0.1-1 Hz. As a result of multiple regression analysis another equations were found between tan δ, viscosity and polyunsaturated fatty acids.

  13. Underestimation of mid-Holocene Arctic warming in PMIP simulations

    Science.gov (United States)

    Zhang, Qiong; Muschitiello, Francesco

    2016-04-01

    Due to the orbital forcing, Arctic is warmer during mid-Holocene (~ 6 kyr BP) in summer because the region received more insolation and also warmer in winter because of strong feedbacks, leads to an annual mean temperature warming. Existing proxy reconstructions show that the Arctic can be two degrees warmer than pre-industrial. However, not all the climate models can capture the warming, and the amplitude is about 0.5 degree less than that seen from proxy data. One possible reason is that these simulations did not take into account a fact of 'Green Sahara', where the large area of Sahara region is covered by vegetation instead of desert as it is today. By using a fully coupled climate model EC-Earth with about 100 km resolution, we have run a series of sensitivity experiments by changing the surface type, as well as accompanied change in dust emission over the northern Sahara. The results show that a green sahara not only results in local climate response such as the northward extension and strengthening of African monsoon, but also affect the large scale circulation and corresponding meridional heat transport. The combination of green sahara and reduced dust entails a general strengthening of the mid-latitude Westerlies, results in a change to more positive North Atlantic Oscillation-like conditions, and more heat transport from lower latitudes to high latitudes both in atmosphere and ocean, eventually leads to a shift towards warmer conditions over the North Atlantic and Arctic regions. This mechanism would explain the sign of rapid hydro-climatic perturbations recorded in several reconstructions from high northern latitudes after the termination of the African Humid Period around 5.5 - 5.0 kyr BP, suggesting that these regions are sensitive to changes in Saharan land cover during the present interglacial. This is central in the debate surrounding Arctic climate amplification and future projections for subtropical precipitation changes and related surface type

  14. Barry Lopez's Relational Arctic

    OpenAIRE

    Kjeldaas, Sigfrid

    2014-01-01

    "Arctic dreams: imagination and desire in a Northern landscape"(1986) can be read as American nature writer Barry Lopez’s attempt to evoke a more profound and ecologically sound understanding of the North American Arctic. This article investigates how Arctic Dreams uses insights from Jacob von Uexküll’s Umwelt theory, in combination with what Tim Ingold describes as a particular form of animism associated with circumpolar indigenous hunter cultures, to portray the Arctic natur...

  15. Fuel Consumption and Fire Emissions Estimates in Siberia: Impact of Vegetation Types, Meteorological Conditions, Forestry Practices and Fire Regimes

    Science.gov (United States)

    Kukavskaya, Elena; Conard, Susan; Ivanova, Galina; Buryak, Ludmila; Soja, Amber; Zhila, Sergey

    2015-04-01

    Boreal forests play a crucial role in carbon budgets with Siberian carbon fluxes and pools making a major contribution to the regional and global carbon cycle. Wildfire is the main ecological disturbance in Siberia that leads to changes in forest species composition and structure and in carbon storage, as well as direct emissions of greenhouse gases and aerosols to the atmosphere. At present, the global scientific community is highly interested in quantitative and accurate estimates of fire emissions. Little research on wildland fuel consumption and carbon emission estimates has been carried out in Russia until recently. From 2000 to 2007 we conducted a series of experimental fires of varying fireline intensity in light-coniferous forest of central Siberia to obtain quantitative and qualitative data on fire behavior and carbon emissions due to fires of known behavior. From 2009 to 2013 we examined a number of burned logged areas to assess the potential impact of forest practices on fire emissions. In 2013-2014 burned areas in dark-coniferous and deciduous forests were examined to determine fuel consumption and carbon emissions. We have combined and analyzed the scarce data available in the literature with data obtained in the course of our long-term research to determine the impact of various factors on fuel consumption and to develop models of carbon emissions for different ecosystems of Siberia. Carbon emissions varied drastically (from 0.5 to 40.9 tC/ha) as a function of vegetation type, weather conditions, anthropogenic effects and fire behavior characteristics and periodicity. Our study provides a basis for better understanding of the feedbacks between wildland fire emissions and changing anthropogenic disturbance patterns and climate. The data obtained could be used by air quality agencies to calculate local emissions and by managers to develop strategies to mitigate negative smoke impacts on the environmentand human health.

  16. ONR Chair in Arctic Marine Science

    Science.gov (United States)

    2016-06-07

    his measurements of ice thickness and heat/salt flux in Terra Nova Bay Polynya should pave the way for new parameterizations of ice growth/ melt in...SEP 1999 2. REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE ONR Chair in Arctic Marine Science 5a. CONTRACT... Arctic Marine Science Robert H. Bourke Department of Oceanography Naval Postgraduate School 833 Dyer Road, Bldg. 232, Rm. 328 Monterey, CA 93943

  17. Islands of the Arctic

    Science.gov (United States)

    Overpeck, Jonathan

    2004-02-01

    Few environments on Earth are changing more dramatically than the Arctic. Sea ice retreat and thinning is unprecedented in the period of the satellite record. Surface air temperatures are the warmest in centuries. The biology of Arctic lakes is changing like never before in millennia. Everything is pointing to the meltdown predicted by climate model simulations for the next 100 years. At the same time, the Arctic remains one of the most pristine and beautiful places on Earth. For both those who know the Arctic and those who want to know it, this book is worth its modest price. There is much more to the Arctic than its islands, but there's little doubt that Greenland and the major northern archipelagos can serve as a great introduction to the environment and magnificence of the Arctic. The book uses the islands of the Arctic to give a good introduction to what the Arctic environment is all about. The first chapter sets the stage with an overview of the geography of the Arctic islands, and this is followed by chapters that cover many key aspects of the Arctic: the geology (origins), weather and climate, glaciers, ice sheets, sea ice, permafrost and other frozen ground issues, coasts, rivers, lakes, animals, people, and environmental impacts. The material is pitched at a level well suited for the interested layperson, but the book will also appeal to those who study the science of the Arctic.

  18. The effects of additional black carbon on Arctic sea ice surface albedo: variation with sea ice type and snow cover

    Directory of Open Access Journals (Sweden)

    A. A. Marks

    2013-03-01

    Full Text Available Black carbon in sea ice will decrease sea ice surface albedo through increased absorption of incident solar radiation, exacerbating sea ice melting. Previous literature has reported different albedo responses to additions of black carbon in sea ice and has not considered how a snow cover may mitigate the effect of black carbon in sea ice. Sea ice is predominately snow covered. Visible light absorption and light scattering coefficients are calculated for a typical first year and multi-year sea ice and "dry" and "wet" snow types that suggest black carbon is the dominating absorbing impurity. The albedo response of first year and multi-year sea ice to increasing black carbon, from 1–1024 ng g−1, in a top 5 cm layer of a 155 cm thick sea ice was calculated using the radiative transfer model: TUV-snow. Sea ice albedo is surprisingly unresponsive to black carbon additions up to 100 ng g−1 with a decrease in albedo to 98.7% of the original albedo value due to an addition of 8 ng g−1 of black carbon in first year sea ice compared to an albedo decrease to 99.6% for the same black carbon mass ratio increase in multi-year sea ice. The first year sea ice proved more responsive to black carbon additions than the multi-year ice. Comparison with previous modelling of black carbon in sea ice suggests a more scattering sea ice environment will be less responsive to black carbon additions. Snow layers on sea ice may mitigate the effects of black carbon in sea ice. "Wet" and "dry" snow layers of 0.5, 1, 2, 5 and 10 cm were added onto the sea ice surface and the snow surface albedo calculated with the same increase in black carbon in the underlying sea ice. Just a 0.5 cm layer of snow greatly diminishes the effect of black carbon on surface albedo, and a 2–5 cm layer (less than half the e-folding depth of snow is enough to "mask" any change in surface albedo owing to additional black carbon in sea ice, but not thick enough to ignore the underlying sea ice.

  19. Plants impact structure and function of bacterial communities in Arctic soils

    NARCIS (Netherlands)

    Kumar, Manoj; Mannisto, Minna K.; van Elsas, Jan Dirk; Nissinen, Riitta M.

    2016-01-01

    Microorganisms are prime drivers of ecosystem functions in the Arctic, and they are essential for vegetation succession. However, very little is known about the phylogenetic and functional diversities of the bacterial communities associated with Arctic plants, especially in low organic matter soils.

  20. Approaching a Postcolonial Arctic

    DEFF Research Database (Denmark)

    Jensen, Lars

    2016-01-01

    This article explores different postcolonially configured approaches to the Arctic. It begins by considering the Arctic as a region, an entity, and how the customary political science informed approaches are delimited by their focus on understanding the Arctic as a region at the service...... of the contemporary neoliberal order. It moves on to explore how different parts of the Arctic are inscribed in a number of sub-Arctic nation-state binds, focusing mainly on Canada and Denmark. The article argues that the postcolonial can be understood as a prism or a methodology that asks pivotal questions to all...... approaches to the Arctic. Yet the postcolonial itself is characterised by limitations, not least in this context its lack of interest in the Arctic, and its bias towards conventional forms of representation in art. The article points to the need to develop a more integrated critique of colonial and neo...

  1. Analysis of heavy metals in different soil types and the vegetables%不同类型土壤及蔬菜中的重金属分析

    Institute of Scientific and Technical Information of China (English)

    谢娟; 田恬; 王莉平; 韩融; 陈爱侠; 何克; 王柱命; 张江华

    2015-01-01

    为了研究不同类型土壤及种植蔬菜中重金属含量,选择两块试验田,种植不同品种蔬菜,分析了土壤及蔬菜中的重金属含量. 试验结果表明:土壤深度为0~80 cm时,两种类型土壤中的重金属Pb、Cu、Zn、Cd、Cr含量随着土壤深度的增加而减小;A区土壤Pb、Cu、Zn含量比B区高;种植的小青菜、小白菜中Pb、Cd、Cr含量A区大于B区;果实类蔬菜对重金属的累积量小于叶菜类.本研究成果可为土壤污染治理提供参考,为人体健康提供依据.%In order to study the content of heavy metals in different soil types and the vegetables planted,this pa-per chooses two plots to plant different varieties of vegetables,and analyzes the heavy metals content in the soil and vegetables.The results show that within the scope of 0 cm to 80 cm,the concentration of heavy metals Pb,Cu,Zn,Cd, Cr in two types of soil decreases with the soil depth.The content of heavy metals Pb,Cu,Zn in A area is higher than B area.The content of heavy metals Pb,Cd,Cr in small brassinca chinensis and small cabbages planted in A area is more than that in B area.Heavy metals accumulation amount in fruit vegetables is less than leaf vegetables.This study pro-vides reference for the soil pollution control and the basis for human health management.

  2. Processes and impacts of Arctic amplification: A research synthesis

    Science.gov (United States)

    Serreze, Mark C.; Barry, Roger G.

    2011-05-01

    The past decade has seen substantial advances in understanding Arctic amplification — that trends and variability in surface air temperature tend to be larger in the Arctic region than for the Northern Hemisphere or globe as a whole. We provide a synthesis of research on Arctic amplification, starting with a historical context and then addressing recent insights into processes and key impacts, based on analysis of the instrumental record, modeling studies, and paleoclimate reconstructions. Arctic amplification is now recognized as an inherent characteristic of the global climate system, with multiple intertwined causes operating on a spectrum of spatial and temporal scales. These include, but are not limited to, changes in sea ice extent that impact heat fluxes between the ocean and the atmosphere, atmospheric and oceanic heat transports, cloud cover and water vapor that alter the longwave radiation flux to the surface, soot on snow and heightened black carbon aerosol concentrations. Strong warming over the Arctic Ocean during the past decade in autumn and winter, clearly associated with reduced sea ice extent, is but the most recent manifestation of the phenomenon. Indeed, periods of Arctic amplification are evident from analysis of both warm and cool periods over at least the past three million years. Arctic amplification being observed today is expected to become stronger in coming decades, invoking changes in atmospheric circulation, vegetation and the carbon cycle, with impacts both within and beyond the Arctic.

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

    Science.gov (United States)

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

    2014-05-01

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

  4. Vegetables and PUFA-rich plant oil reduce DNA strand breaks in individuals with type 2 diabetes

    DEFF Research Database (Denmark)

    Müllner, Elisabeth; Brath, Helmut; Pleifer, Simone;

    2013-01-01

    (Comet Assay), urinary excretion of 8-oxo-7-hydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and glycated hemoglobin (HbA1c) were measured at baseline, after 4, 8 (end of intervention), and 16 weeks. The intervention with vegetables and PUFA-rich oil led to a significant...

  5. The effects of additional black carbon on the albedo of Arctic sea ice: variation with sea ice type and snow cover

    Directory of Open Access Journals (Sweden)

    A. A. Marks

    2013-07-01

    Full Text Available The response of the albedo of bare sea ice and snow-covered sea ice to the addition of black carbon is calculated. Visible light absorption and light-scattering cross-sections are derived for a typical first-year and multi-year sea ice with both "dry" and "wet" snow types. The cross-sections are derived using data from a 1970s field study that recorded both reflectivity and light penetration in Arctic sea ice and snow overlying sea ice. The variation of absorption cross-section over the visible wavelengths suggests black carbon is the dominating light-absorbing impurity. The response of first-year and multi-year sea ice albedo to increasing black carbon, from 1 to 1024 ng g−1, in a top 5 cm layer of a 155 cm-thick sea ice was calculated using a radiative-transfer model. The albedo of the first-year sea ice is more sensitive to additional loadings of black carbon than the multi-year sea ice. An addition of 8 ng g−1 of black carbon causes a decrease to 98.7% of the original albedo for first-year sea ice compared to a decrease to 99.7% for the albedo of multi-year sea ice, at a wavelength of 500 nm. The albedo of sea ice is surprisingly unresponsive to additional black carbon up to 100 ng g−1 . Snow layers on sea ice may mitigate the effects of black carbon in sea ice. Wet and dry snow layers of 0.5, 1, 2, 5 and 10 cm depth were added onto the sea ice surface. The albedo of the snow surface was calculated whilst the black carbon in the underlying sea ice was increased. A layer of snow 0.5 cm thick greatly diminishes the effect of black carbon in sea ice on the surface albedo. The albedo of a 2–5 cm snow layer (less than the e-folding depth of snow is still influenced by the underlying sea ice, but the effect of additional black carbon in the sea ice is masked.

  6. Decadal changes of phenological patterns over Arctic tundra biome

    Science.gov (United States)

    Jia, G. J.; Epstein, H. E.; Walker, D. A.; Wang, H.

    2008-12-01

    The northern high latitudes have experienced a continuous and accelerated trend of warming during the past 30 years, with most recent decade ranks the warmest years since 1850. Warmer springs are especially evident throughout the Arctic. Meanwhile, Arctic sea ice declined rapidly to unprecedented low extents in all months, with late summer experiences the most significant declining. Warming in the north is also evident from observations of early melting of snow and reducing snow cover. Now a key question is: in the warmth limited northern biome, what will happen to the phenological patterns of tundra vegetation as the global climate warms and seasonality of air temperature, sea ice, and snow cover shift? To answer the question we examined the onset of vegetation greenness, senescence of greenness, length of growing season, and dates of peak greenness along Arctic bioclimate gradients (subzones) to see how they change over years. Here, we combine multi-scale sub-pixel analysis and remote sensing time-series analysis to investigate recent decadal changes in vegetation phenology along spatial gradients of summer temperature and vegetation in the Arctic. The datasets used here are AVHRR 15-day 8 km time series, AVHRR 8-day 1 km dataset, and MODIS 8-day 500m Collection 5 dataset. There were detectable changes in phenological pattern over tundra biome in past two decades. Increases of vegetation greenness were observed in most of the summer periods in low arctic and mid-summer in high arctic. Peak greenness appeared earlier in high arctic and declined slower after peak in low arctic. Generally, tundra plants were having longer and stronger photosynthesis activities, and therefore increased annual vegetation productivities. Field studies have observed early growth and enhanced peak growth of many deciduous shrub species in tundra plant communities. These changes in seasonality are very likely to alter surface albedo and heat budget, modify plant photosynthesis

  7. Projected impacts of 21st century climate change on the distribution of potential habitat for vegetation, forest types and major conifer species across Russia.

    Science.gov (United States)

    Tchebakova, Nadezda; Parfenova, Elena; Cantin, Alan; Shvetsov, Eugene; Soja, Amber; Conard, Susane

    2013-04-01

    Global simulations have demonstrated the potential for profound effects of GCM-projected climate change on the distribution of terrestrial ecosystems and individual species at all hierarchical levels. We modeled progressions of potential vegetation cover, forest cover and forest types in Russia in the warming climate during the 21st century. We used large-scale bioclimatic models to predict zonal vegetation (RuBCliM), and forest cover (ForCliM) and forest types. A forest type was defined as a combination of a dominant tree conifer and a ground layer. Distributions of vegetation zones (zonobiomes), conifer species and forest types were simulated based on three bioclimatic indices (1) growing degree-days above 5oC ; (2) negative degree-days below 0oC; and (3) an annual moisture index (ratio of growing degree days to annual precipitation). Additionally, the presence/absence of continuous permafrost, identified by active layer depth of 2 m, was explicitly included in the models as limiting the forests and tree species distribution in Siberia. All simulations to predict vegetation change across Russia were run by coupling our bioclimatic models with bioclimatic indices and the permafrost distribution for the baseline period 1971-2000 and for the future decades of 2011-2020, 2041-2050 and 2091-2100. To provide a range of warming we used three global climate models (CGCM3.1, HadCM3 and IPSLCM4) and three climate change scenarios (A1B, A2 and B1). The CGCM model and the B1 scenario projected the smallest temperature increases, and the IPSL model and the A2 scenario projected the greatest temperature increases. We compared the modeled vegetation and the modeled tree species distributions in the contemporary climate to actual vegetation and forest maps using Kappa (K) statistics. RuBioCliM models of Russian zonal vegetation were fairly accurate (K= 0.40). Contemporary major conifer species (Pinus sibirica, Pinus sylvestris, Larix spp., Abies sibirica and Picea obovata

  8. Balkan Vegetation Database

    NARCIS (Netherlands)

    Vassilev, Kiril; Pedashenko, Hristo; Alexandrova, Alexandra; Tashev, Alexandar; Ganeva, Anna; Gavrilova, Anna; Gradevska, Asya; Assenov, Assen; Vitkova, Antonina; Grigorov, Borislav; Gussev, Chavdar; Filipova, Eva; Aneva, Ina; Knollová, Ilona; Nikolov, Ivaylo; Georgiev, Georgi; Gogushev, Georgi; Tinchev, Georgi; Pachedjieva, Kalina; Koev, Koycho; Lyubenova, Mariyana; Dimitrov, Marius; Apostolova-Stoyanova, Nadezhda; Velev, Nikolay; Zhelev, Petar; Glogov, Plamen; Natcheva, Rayna; Tzonev, Rossen; Boch, Steffen; Hennekens, Stephan M.; Georgiev, Stoyan; Stoyanov, Stoyan; Karakiev, Todor; Kalníková, Veronika; Shivarov, Veselin; Russakova, Veska; Vulchev, Vladimir

    2016-01-01

    The Balkan Vegetation Database (BVD; GIVD ID: EU-00-019; http://www.givd.info/ID/EU-00- 019) is a regional database that consists of phytosociological relevés from different vegetation types from six countries on the Balkan Peninsula (Albania, Bosnia and Herzegovina, Bulgaria, Kosovo, Montenegro

  9. Agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetlands: A case study in the Yellow River wetland in China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Tongqian; XU Huashan; HE Yuxiao; TAI Chao; MENG Hongqi; ZENG Fanfu; XING Menglin

    2009-01-01

    Riparian wetland is the major transition zone of matter, energy and information transfer between aquatic and terrestrial ecosystems and has important functions of water purification and non-point pollution control. Using the field experiment method and an isotope tracing technique, the agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetland was studied in the Kouma Section of the Yellow River. The results showed that the retention of agricultural non-point nitrogen pollution by riparian wetland soil occurs mainly in top 0-10 cm layer. The amount of nitrogen retained by surface soils associated with three types of vegetation are 0.045 mg/g for Phragmites communis Trin Lima, 0.036 mg/g for Scirpus triqueter Liun, and 0.032 mg/g for Typha angustifolia Linn, which account for 59.21%, 56.25%, and 56.14% of the total nitrogen interception, respectively. Exogenous nitrogen in 0-10 cm soil layer changes more quickly than in other layers. One month after adding K15NO3 to the tested vegetation, nitrogen content was 77.78% for P. Communis Trin, 68.75% for T. Angustifolia, and 8.33% for S. Triqueter in the surface soil. After three months, nitrogen content was 93.33% for P. Communis Trin, 72.22% for S. Triqueter, and 37.50% for T. Angustifolia. There are large differences among vegetation communities respecting to purification of agricultural non-point nitrogen pollution. The nitrogen uptake amount decreases in the sequence: new shoots of P. Communis Trin (9.731 mg/g)>old P. Communis Trin (4.939 mg/g)>S. Triqueter (0.620 mg/g)>T. Angustifolia (0.186 mg/g). Observations indicated that the presence of riparian wetlands as buffers on and adjacent to stream banks could be recommended to control agricultural non-point pollution.

  10. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model

    Science.gov (United States)

    Euskirchen, E.S.; Carman, T.B.; McGuire, Anthony David

    2013-01-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970 -2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared to simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.

  11. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model.

    Science.gov (United States)

    Euskirchen, Eugénie S; Carman, Tobey B; McGuire, A David

    2014-03-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970-2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared with simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.

  12. Challenges in modelling isoprene and monoterpene emission dynamics of Arctic plants: a case study from a subarctic tundra heath

    Science.gov (United States)

    Tang, Jing; Schurgers, Guy; Valolahti, Hanna; Faubert, Patrick; Tiiva, Päivi; Michelsen, Anders; Rinnan, Riikka

    2016-12-01

    effect of plant functional type (PFT) dynamics and instantaneous BVOC responses to warming. The identified challenges in estimating Arctic BVOC emissions are (1) correct leaf T estimation, (2) PFT parameterization accounting for plant emission features as well as physiological responses to warming, and (3) representation of long-term vegetation changes in the past and the future.

  13. Long-term recovery patterns of arctic tundra after winter seismic exploration.

    Science.gov (United States)

    Jorgenson, Janet C; Ver Hoef, Jay M; Jorgenson, M T

    2010-01-01

    In response to the increasing global demand for energy, oil exploration and development are expanding into frontier areas of the Arctic, where slow-growing tundra vegetation and the underlying permafrost soils are very sensitive to disturbance. The creation of vehicle trails on the tundra from seismic exploration for oil has accelerated in the past decade, and the cumulative impact represents a geographic footprint that covers a greater extent of Alaska's North Slope tundra than all other direct human impacts combined. Seismic exploration for oil and gas was conducted on the coastal plain of the Arctic National Wildlife Refuge, Alaska, USA, in the winters of 1984 and 1985. This study documents recovery of vegetation and permafrost soils over a two-decade period after vehicle traffic on snow-covered tundra. Paired permanent vegetation plots (disturbed vs. reference) were monitored six times from 1984 to 2002. Data were collected on percent vegetative cover by plant species and on soil and ground ice characteristics. We developed Bayesian hierarchical models, with temporally and spatially autocorrelated errors, to analyze the effects of vegetation type and initial disturbance levels on recovery patterns of the different plant growth forms as well as soil thaw depth. Plant community composition was altered on the trails by species-specific responses to initial disturbance and subsequent changes in substrate. Long-term changes included increased cover of graminoids and decreased cover of evergreen shrubs and mosses. Trails with low levels of initial disturbance usually improved well over time, whereas those with medium to high levels of initial disturbance recovered slowly. Trails on ice-poor, gravel substrates of riparian areas recovered better than those on ice-rich loamy soils of the uplands, even after severe initial damage. Recovery to pre-disturbance communities was not possible where trail subsidence occurred due to thawing of ground ice. Previous studies of

  14. Arctic wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, E. [Kemijoki Oy (Finland); Holttinen, H.; Marjaniemi, M. [VTT Energy, Espoo (Finland); Tammelin, B. [Finnish Meteorological Institute, Helsinki (Finland)

    1998-12-31

    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  15. Arctic tipping points

    OpenAIRE

    Smolkova, Valentina

    2015-01-01

    The Arctic is warming much faster than the entire planet, and this causes severe melting of sea ice. However, the climate of different regions of the Earth is interconnected, and changes in the amount of ice in the Arctic can dramatically affect the climate across the whole planet. Some scientists claim that a possible tipping point is the event of the ice-free Arctic Ocean in summer. Certain predictions point towards ice-free Arctic summers around the year 2050, whereas others pre- dict this...

  16. Comparison of different cutaneous carotenoid sensors and influence of age, skin type, and kinetic changes subsequent to intake of a vegetable extract

    Science.gov (United States)

    Meinke, Martina C.; Schanzer, Sabine; Lohan, Silke B.; Shchatsinin, Ihar; Darvin, Maxim E.; Vollert, Henning; Magnussen, Björn; Köcher, Wolfang; Helfmann, Jürgen; Lademann, Jürgen

    2016-10-01

    In the last decade, cutaneous carotenoid measurements have become increasingly popular, as carotenoids were found to be a biomarker of nutrition rich in fruits and vegetables, permitting monitoring of the influence of various stress factors. For such measurements, in addition to the specific and selective resonance Raman spectroscopy (RRS), newly developed low expensive small and mobile sensors that are based on spatially resolved reflectance spectroscopy (SRRS) are used for cutaneous carotenoid measurements. Human volunteers of different age exhibiting skin types I to III were investigated using RRS and two SRRS-based sensors to determine the influence of these parameters on the measuring results. In two studies on volunteers of either the same age or skin type, however, the respective other parameter being varied and no significant influences of age or skin type could be detected. Furthermore, the kinetic changes resulting from the intake and discontinued intake of a vegetable extract rich in carotenoids showed a good correlation among the three sensors and with the detected blood carotenoids. This illustrates that the SRRS-based sensors and RRS device provide reliable cutaneous carotenoid values independent of age and skin types I to III of the volunteers.

  17. Climate change and Arctic ecosystems: 2. Modeling, paleodata-model comparisons, and future projections

    Science.gov (United States)

    Kaplan, J.O.; Bigelow, N.H.; Prentice, I.C.; Harrison, S.P.; Bartlein, P.J.; Christensen, T.R.; Cramer, W.; Matveyeva, N.V.; McGuire, A.D.; Murray, D.F.; Razzhivin, V.Y.; Smith, B.; Walker, D. A.; Anderson, P.M.; Andreev, A.A.; Brubaker, L.B.; Edwards, M.E.; Lozhkin, A.V.

    2003-01-01

    Large variations in the composition, structure, and function of Arctic ecosystems are determined by climatic gradients, especially of growing-season warmth, soil moisture, and snow cover. A unified circumpolar classification recognizing five types of tundra was developed. The geographic distributions of vegetation types north of 55??N, including the position of the forest limit and the distributions of the tundra types, could be predicted from climatology using a small set of plant functional types embedded in the biogeochemistry-biogeography model BIOME4. Several palaeoclimate simulations for the last glacial maximum (LGM) and mid-Holocene were used to explore the possibility of simulating past vegetation patterns, which are independently known based on pollen data. The broad outlines of observed changes in vegetation were captured. LGM simulations showed the major reduction of forest, the great extension of graminoid and forb tundra, and the restriction of low- and high-shrub tundra (although not all models produced sufficiently dry conditions to mimic the full observed change). Mid-Holocene simulations reproduced the contrast between northward forest extension in western and central Siberia and stability of the forest limit in Beringia. Projection of the effect of a continued exponential increase in atmospheric CO2 concentration, based on a transient ocean-atmosphere simulation including sulfate aerosol effects, suggests a potential for larger changes in Arctic ecosystems during the 21st century than have occurred between mid-Holocene and present. Simulated physiological effects of the CO2 increase (to > 700 ppm) at high latitudes were slight compared with the effects of the change in climate.

  18. Arctic tree rings as recorders of variations in light availability.

    Science.gov (United States)

    Stine, A R; Huybers, P

    2014-05-07

    Annual growth ring variations in Arctic trees are often used to reconstruct surface temperature. In general, however, the growth of Arctic vegetation is limited both by temperature and light availability, suggesting that variations in atmospheric transmissivity may also influence tree-ring characteristics. Here we show that Arctic tree-ring density is sensitive to changes in light availability across two distinct phenomena: explosive volcanic eruptions (Ptree-ring density relative to temperature is seen in the least light-limited regions of the Arctic. Consistent results follow from analysis of tree-ring width and from individually analysing each of seven tree species. Light availability thus appears an important control, opening the possibility for using tree rings to reconstruct historical changes in surface light intensity.

  19. Vegetation survey: a new focus for Applied Vegetation Science

    NARCIS (Netherlands)

    Chytry, M.; Schaminee, J.H.J.; Schwabe, A.

    2011-01-01

    Vegetation survey is an important research agenda in vegetation science. It defines vegetation types and helps understand differences among them, which is essential for both basic ecological research and applications in biodiversity conservation and environmental monitoring. In this editorial, we re

  20. White Arctic vs. Blue Arctic: Making Choices

    Science.gov (United States)

    Pfirman, S. L.; Newton, R.; Schlosser, P.; Pomerance, R.; Tremblay, B.; Murray, M. S.; Gerrard, M.

    2015-12-01

    As the Arctic warms and shifts from icy white to watery blue and resource-rich, tension is arising between the desire to restore and sustain an ice-covered Arctic and stakeholder communities that hope to benefit from an open Arctic Ocean. If emissions of greenhouse gases to the atmosphere continue on their present trend, most of the summer sea ice cover is projected to be gone by mid-century, i.e., by the time that few if any interventions could be in place to restore it. There are many local as well as global reasons for ice restoration, including for example, preserving the Arctic's reflectivity, sustaining critical habitat, and maintaining cultural traditions. However, due to challenges in implementing interventions, it may take decades before summer sea ice would begin to return. This means that future generations would be faced with bringing sea ice back into regions where they have not experienced it before. While there is likely to be interest in taking action to restore ice for the local, regional, and global services it provides, there is also interest in the economic advancement that open access brings. Dealing with these emerging issues and new combinations of stakeholders needs new approaches - yet environmental change in the Arctic is proceeding quickly and will force the issues sooner rather than later. In this contribution we examine challenges, opportunities, and responsibilities related to exploring options for restoring Arctic sea ice and potential pathways for their implementation. Negotiating responses involves international strategic considerations including security and governance, meaning that along with local communities, state decision-makers, and commercial interests, national governments will have to play central roles. While these issues are currently playing out in the Arctic, similar tensions are also emerging in other regions.

  1. Vegetation type and the presence of ash as factors in the evolution of soil water repellency after a forest fire

    Directory of Open Access Journals (Sweden)

    P. Jiménez-Pinilla

    2013-05-01

    Full Text Available After wildfires, burning may induce the occurrence of soil water repellency. Soil water repellency may vary in space and time in function of vegetation, the presence of ash and soil moisture. This study analyzes the evolution of fire-induced soil water repellency in function of these factors, and proposes measures to promote the restoration of fire-affected soils. Burnt and unburnt (control soil plots under pine and shrub from a recently burned area (Gorga, Alicante, SE Spain were established. Three treatments were applied: in some of the plots, the original ash layer was kept on the ground; in a second group, the ash layer was removed for simulating the effects of erosion; finally, in a third group, percolating irrigation was conducted to simulate a possible good input of water into the soil profile after burning, that could occur if the first rains were with high quantity but low intensity. During the dry season, soil moisture content was significantly lower in burned plots due to fire-induced water repellency and reduced vegetation cover. During the wet season, soil moisture decreased in the control unburnt plots due to direct evaporation of water intercepted by vegetation and consumption by roots. Fire increased soil water repellency only in plots under pine. Water repellency decreased during the wet season, disappearing in January and reappearing after declining rainfalls. This baseline recovery of soil water repellency was lower where ash removal was simulated. In unburned plots, seasonal fluctuations were less important. In general, ash removal promotes a rapid reduction of water repellency, since it can induce washing of hydrophobic compounds. Irrigation performed immediately after the fire also contributed to decreased water repellency.

  2. Description and validation of an automated methodology for mapping mineralogy, vegetation, and hydrothermal alteration type from ASTER satellite imagery with examples from the San Juan Mountains, Colorado

    Science.gov (United States)

    Rockwell, Barnaby W.

    2012-01-01

    The efficacy of airborne spectroscopic, or "hyperspectral," remote sensing for geoenvironmental watershed evaluations and deposit-scale mapping of exposed mineral deposits has been demonstrated. However, the acquisition, processing, and analysis of such airborne data at regional and national scales can be time and cost prohibitive. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor carried by the NASA Earth Observing System Terra satellite was designed for mineral mapping and the acquired data can be efficiently used to generate uniform mineral maps over very large areas. Multispectral remote sensing data acquired by the ASTER sensor were analyzed to identify and map minerals, mineral groups, hydrothermal alteration types, and vegetation groups in the western San Juan Mountains, Colorado, including the Silverton and Lake City calderas. This mapping was performed in support of multidisciplinary studies involving the predictive modeling of surface water geochemistry at watershed and regional scales. Detailed maps of minerals, vegetation groups, and water were produced from an ASTER scene using spectroscopic, expert system-based analysis techniques which have been previously described. New methodologies are presented for the modeling of hydrothermal alteration type based on the Boolean combination of the detailed mineral maps, and for the entirely automated mapping of alteration types, mineral groups, and green vegetation. Results of these methodologies are compared with the more detailed maps and with previously published mineral mapping results derived from analysis of high-resolution spectroscopic data acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) sensor. Such comparisons are also presented for other mineralized and (or) altered areas including the Goldfield and Cuprite mining districts, Nevada and the central Marysvale volcanic field, Wah Wah Mountains, and San Francisco Mountains, Utah. The automated

  3. PAST Gateways (Palaeo-Arctic Spatial and Temporal Gateways): Introduction and overview

    Science.gov (United States)

    Ó Cofaigh, Colm; Briner, Jason P.; Kirchner, Nina; Lucchi, Renata G.; Meyer, Hanno; Kaufman, Darrell S.

    2016-09-01

    This special issue relates to the Second International Conference of the PAST Gateways (Palaeo-Arctic Spatial and Temporal Gateways) network which was held in Trieste, Italy in 2014. Twenty five papers are included and they address topics under four main themes: (1) The growth and decay of Arctic ice sheets; (2) Arctic sea ice and palaeoceanography; (3) Terrestrial Arctic environments and permafrost change; and (4) Holocene Arctic environmental change. Geographically the focus is circum-Arctic; the special issue includes detailed regional studies from Greenland, Scandinavia, Russia, and Arctic North America and the adjoining seas, as well as a series of synthesis-type, review papers on Fennoscandian Ice Sheet deglaciation and Holocene Arctic palaeo-climate change. The methodologies employed are diverse and include marine sediment core and geophysical investigations, terrestrial glacial geology and geomorphology, isotopic analysis of ground ice, palaeo-ecological analysis of lacustrine and terrestrial sedimentary archives, geochronology and numerical ice sheet modeling.

  4. Vegetation cover and relationships of habitat-type with elevation on the Mississippi-Alabama Barrier Islands in the initial six years after Hurricane Katrina

    Science.gov (United States)

    Funderburk, W.; Carter, G. A.; Anderson, C. P.; Jeter, G. W., Jr.; Otvos, E. G.; Lucas, K. L.; Hopper, N. L.

    2015-12-01

    Quantifying change in vegetation and geomorphic features which occur during and after storm impact is necessary toward understanding barrier island habitat resiliency under continued climate warming and sea level rise. In August, 2005, the Mississippi-Alabama barrier islands, including, from west-to-east, Cat, West Ship, East Ship, Horn, Petit Bois and Dauphin islands, were completely inundated by the tidal surge of Hurricane Katrina. Overwash, scouring, burial under sand, and mechanical damage combined with saltwater flooding and post-storm drought resulted in immediate and long-term vegetation loss. Remotely-sensed data acquired before (2004-2005) and after (2005-2011) Katrina were compared via image classification to determine immediate storm impacts and assess natural re-growth of land area and vegetation. By 2008, merely three years after the storm, total land area of Cat, West Ship, East Ship, Horn, Petit Bois and West Dauphin had recovered to 92, 90, 33, 99, 93 and 91 percent, and total vegetated land area to 85, 101, 85, 94, 83 and 102 percent of pre-Katrina values, respectively. Habitat-type maps developed from field survey, SPOT-5 and radar data were compared with LIDAR-derived elevation models to assess 2010 habitat-type distribution with respect to ground elevation. Although median MSL elevations associated with habitat classes ranged only from 0.5 m to 1.4 m, habitat-type changed distinctively with decimeter-scale changes in elevation. Low marsh, high marsh, estuarine shrubland, slash pine woodland, beach dune, bare sand and beach dune herbland were associated with median elevations of 0.5, 0.9, 1.0, 1.1, 1.2, 1.3 and 1.4 m ± 0.1 m, respectively. The anticipated increases in sea level and tropical storm energy under a continually warming climate will likely inhibit the reformation of higher-elevation habitat-types, such as shrublands and woodlands, in the 21st century.

  5. Study on Climatic Variation and Its Effect on Vegetable Type Soybean Genotypes at Khumaltar, Lalitpur in the Last Ten Years

    Directory of Open Access Journals (Sweden)

    Santosh Raj Tripathi

    2015-03-01

    Full Text Available Soybean (Glycine max L. Merril is widely grown in the mid hills as intercrop with maize or in paddy bunds, while it is gaining popularity as sole crop in terai and inner terai. Mean temperature at Khumaltar during soybean growing period was mostly fluctuating; but we observed an increasing trend in temperature. Amount of rainfall was not changed dramatically but number of rainy days was decreased during study period. Rainfall during germination time increase soil moisture which also increase germination and found higher early stand. Days from sowing to 50% flowering and 90% maturity were short in the case of higher minimum temperature and low rainfall. Among the genotypes, AGS-377, AGS-378, AGS-379 and Tarkari Bhattmas-1 were more sensitive. However, seed yield decreased in the case of higher temperatures and low rainfall. Cool night temperatures and high moisture increased disease incidence in soybean which, eventually reduced yield. In last three years, plant suffered from moisture stress during early vegetative stage and high moisture during late vegetative stage which reduced seed yield and seed weight. In conclusion, we found that genotypes like AGS- 360, Sathiya and Tarkari Bhatmas-1 are very sensitive to climatic variation.

  6. Plasmid pP62BP1 isolated from an Arctic Psychrobacter sp. strain carries two highly homologous type II restriction-modification systems and a putative organic sulfate metabolism operon.

    Science.gov (United States)

    Lasek, Robert; Dziewit, Lukasz; Bartosik, Dariusz

    2012-05-01

    The complete nucleotide sequence of plasmid pP62BP1 (34,467 bp), isolated from Arctic Psychrobacter sp. DAB_AL62B, was determined and annotated. The conserved plasmid backbone is composed of several genetic modules, including a replication system (REP) with similarities to the REP region of the iteron-containing plasmid pPS10 of Pseudomonas syringae. The additional genetic load of pP62BP1 includes two highly related type II restriction-modification systems and a set of genes (slfRCHSL) encoding enzymes engaged in the metabolism of organic sulfates, plus a putative transcriptional regulator (SlfR) of the AraC family. The pP62BP1 slf locus has a compact and unique structure. It is predicted that the enzymes SlfC, SlfH, SlfS and SlfL carry out a chain of reactions leading to the transformation of alkyl sulfates into acyl-CoA, with dodecyl sulfate (SDS) as a possible starting substrate. Comparative analysis of the nucleotide sequences of pP62BP1 and other Psychrobacter spp. plasmids revealed their structural diversity. However, the presence of a few highly conserved DNA segments in pP62BP1, plasmid 1 of P. cryohalolentis K5 and pRWF-101 of Psychrobacter sp. PRwf-1 is indicative of recombinational shuffling of genetic information, and is evidence of lateral gene transfer in the Arctic environment.

  7. Ice-Free Arctic Ocean?

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    The current warming trends in the Arctic may shove the Arctic system into a seasonally ice-free state not seen for more than one million years, according to a new report. The melting is accelerating, and researchers were unable to identify any natural processes that might slow the deicing of the Arctic. "What really makes the Arctic different…

  8. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    method.For oceanographic purposes, the altimetric record over the Arctic Ocean is inferiorin quality to that of moderate latitudes, but nonetheless an invaluable set of observations. During this project, newly processed Arctic altimetry from the ERS-1/-2 and Envisat missions has become available......Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...

  9. Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra

    Science.gov (United States)

    Juszak, Inge; Eugster, Werner; Heijmans, Monique M. P. D.; Schaepman-Strub, Gabriela

    2016-07-01

    Vegetation changes, such as shrub encroachment and wetland expansion, have been observed in many Arctic tundra regions. These changes feed back to permafrost and climate. Permafrost can be protected by soil shading through vegetation as it reduces the amount of solar energy available for thawing. Regional climate can be affected by a reduction in surface albedo as more energy is available for atmospheric and soil heating. Here, we compared the shortwave radiation budget of two common Arctic tundra vegetation types dominated by dwarf shrubs (Betula nana) and wet sedges (Eriophorum angustifolium) in North-East Siberia. We measured time series of the shortwave and longwave radiation budget above the canopy and transmitted radiation below the canopy. Additionally, we quantified soil temperature and heat flux as well as active layer thickness. The mean growing season albedo of dwarf shrubs was 0.15 ± 0.01, for sedges it was higher (0.17 ± 0.02). Dwarf shrub transmittance was 0.36 ± 0.07 on average, and sedge transmittance was 0.28 ± 0.08. The standing dead leaves contributed strongly to the soil shading of wet sedges. Despite a lower albedo and less soil shading, the soil below dwarf shrubs conducted less heat resulting in a 17 cm shallower active layer as compared to sedges. This result was supported by additional, spatially distributed measurements of both vegetation types. Clouds were a major influencing factor for albedo and transmittance, particularly in sedge vegetation. Cloud cover reduced the albedo by 0.01 in dwarf shrubs and by 0.03 in sedges, while transmittance was increased by 0.08 and 0.10 in dwarf shrubs and sedges, respectively. Our results suggest that the observed deeper active layer below wet sedges is not primarily a result of the summer canopy radiation budget. Soil properties, such as soil albedo, moisture, and thermal conductivity, may be more influential, at least in our comparison between dwarf shrub vegetation on relatively dry patches and

  10. Seasonal Dynamics of Soil Labile Organic Carbon and Enzyme Activities in Relation to Vegetation Types in Hangzhou Bay Tidal Flat Wetland.

    Science.gov (United States)

    Shao, Xuexin; Yang, Wenying; Wu, Ming

    2015-01-01

    Soil labile organic carbon and soil enzymes play important roles in the carbon cycle of coastal wetlands that have high organic carbon accumulation rates. Soils under three vegetations (Phragmites australis, Spartina alterniflora, and Scirpusm mariqueter) as well as bare mudflat in Hangzhou Bay wetland of China were collected seasonally. Seasonal dynamics and correlations of soil labile organic carbon fractions and soil enzyme activities were analyzed. The results showed that there were significant differences among vegetation types in the contents of soil organic carbon (SOC) and dissolved organic carbon (DOC), excepting for that of microbial biomass carbon (MBC). The P. australis soil was with the highest content of both SOC (7.86 g kg-1) and DOC (306 mg kg-1), while the S. mariqueter soil was with the lowest content of SOC (6.83 g kg-1), and the bare mudflat was with the lowest content of DOC (270 mg kg-1). Soil enzyme activities were significantly different among vegetation types except for urease. The P. australis had the highest annual average activity of alkaline phosphomonoesterase (21.4 mg kg-1 h-1), and the S. alterniflora had the highest annual average activities of β-glycosidase (4.10 mg kg-1 h-1) and invertase (9.81 mg g-1 24h-1); however, the bare mudflat had the lowest activities of alkaline phosphomonoesterase (16.2 mg kg-1 h-1), β-glycosidase (2.87 mg kg-1 h-1), and invertase (8.02 mg g-1 24h-1). Analysis also showed that the soil labile organic carbon fractions and soil enzyme activities had distinct seasonal dynamics. In addition, the soil MBC content was significantly correlated with the activities of urease and β-glucosidase. The DOC content was significantly correlated with the activities of urease, alkaline phosphomonoesterase, and invertase. The results indicated that vegetation type is an important factor influencing the spatial-temporal variation of soil enzyme activities and labile organic carbon in coastal wetlands.

  11. Improvement of boreal vegetation modelling and climate interactions through the introduction of new bryophyte and artic-shrub plant functional types in a land surface model.

    Science.gov (United States)

    Druel, Arsène; Krinner, Gerhard; Peylin, Philippe; Ciais, Philippe; Viovy, Nicolas; Peregon, Anna

    2016-04-01

    Boreal and tundra vegetation, which represents 22% of the global land area, has had a significant impact on climate through changes of albedo, snow cover, soil thermal dynamics, etc. However, it is frequently poorly represented in earth system models used for climate predictions. We improved the description of high-latitude vegetation and its interactions with the environment in the ORCHIDEE land surface model by creating new plant functional types with specific biogeochemical and biophysical properties: boreal shrubs, bryophytes (mosses and lichens) and boreal C3 grasses. The introduction of shrub specificities allows for an intermediate stratum between trees and grasses, with a new carbon allometry within the plant, inducing new interactions between wooden species and their environment, especially the complex snow-shrubs interaction. Similarly, the introduction of non-vascular plants (i.e. bryophytes) involves numerous changes both in physical and biological processes, such as the response of photosynthesis to surface humidity, the decomposition of carbon and the soil thermal conductivity. These changes in turn lead to new processes and interactions between vegetation and moisture (soil and air), carbon cycle, energy balance, etc. For the boreal C3 grasses we did not include new processes compared to the generic C3 grass PFT, but improved the realism of the carbon and water budgets with new boreal adjusted parameters. We assess the performance of the modified ORCHIDEE land surface model and in particular its ability to represent the new plant types (their phenology etc.), and evaluate the effects of these new PFTs on the simulated energy, water and carbon balances of boreal ecosystems. The potential impact of these refinements on future climate simulations will be discussed.

  12. Influence of BRDF on NDVI and biomass estimations of Alaska Arctic tundra

    Science.gov (United States)

    Buchhorn, Marcel; Raynolds, Martha K.; Walker, Donald A.

    2016-12-01

    Satellites provide the only practical source of data for estimating biomass of large and remote areas such as the Alaskan Arctic. Researchers have found that the normalized difference vegetation index (NDVI) correlates well with biomass sampled on the ground. However, errors in NDVI and biomass estimates due to bidirectional reflectance distribution function (BRDF) effects are not well reported in the literature. Sun-sensor-object geometries and sensor band-width affect the BRDF, and formulas relating NDVI to ground-sampled biomass vary between projects. We examined the effects of these different variables on five studies that estimated above-ground tundra biomass of two common arctic vegetation types that dominate the Alaska tundra, moist acidic tussock tundra (MAT) and moist non-acidic tundra (MNT). We found that biomass estimates were up to 33% (excluding extremes) more sensitive than NDVI to BRDF effects. Variation between the sensors resulted in differences in NDVI of under 3% over all viewing geometries, and wider bands were more stable in their biomass estimates than narrow bands. MAT was more sensitive than MNT to BRDF effects due to irregularities in surface reflectance created by the tussocks. Finally, we found that studies that sampled only a narrow range of biomass and NDVI produced equations that were more difficult to correct for BRDF effects.

  13. Five Years of Land Surface Phenology in a Large Scale Hydrological Manipulation Experiment in an Arctic Tundra Landscape

    Science.gov (United States)

    Goswami, S.; Gamon, J. A.; Tweedie, C. E.

    2010-12-01

    Climate change appears to be most pronounced at high northern latitudes. Many of the observed and modeled climate change responses in arctic tundra ecosystems have profound effects on surface energy budgets, land-atmosphere carbon exchange, plant phenology, and geomorphic processes. Detecting biotic responses to a changing environment is essential for understanding the consequences of global change. Plants can work as very effective indicators of changing conditions and, depending on the nature of the change, respond by increasing or decreasing amounts of green-leaf biomass, chlorophyll, and water content. Shifts in the composition and abundance of plant species have important effects on ecosystem processes such as net primary production and nutrient cycling. Vegetation is expected to be responsive to arctic warming, although there is some uncertainty as to how the interplay between geomorphic, hydrologic, climatic and other biotic will manifest over a range of spatial scales. The NSF-supported Biocomplexity project in Barrow, Alaska, involves experimental manipulation of water table (drained, flooded, and control treatments) in a vegetated arctic thaw lake basin to investigate the effects of altered hydrology on land-atmosphere carbon balance. In each experimental treatment, hyperspectral reflectance data were collected in the visible and near IR range of the spectrum using a robotic tram system that operated along a 300m tramline during the snow free growing period between June and August 2005-09. Water table depths and soil volumetric water content was also collected along these transects. The years 2005-2007 were control or unmanipulated experimental years and 2008 and 2009 were experimental years where water table was raised (+10cm) and lowered (-10cm) in flooding and draining experiments respectively. This presentation will document the change in phenology (NDVI) between years, treatments, and land cover types. Findings from this research have implications

  14. High Arctic plant phenology is determined by snowmelt patterns but duration of phenological periods is fixed: an example of periodicity

    Science.gov (United States)

    Semenchuk, Philipp R.; Gillespie, Mark A. K.; Rumpf, Sabine B.; Baggesen, Nanna; Elberling, Bo; Cooper, Elisabeth J.

    2016-12-01

    The duration of specific periods within a plant’s life cycle are critical for plant growth and performance. In the High Arctic, the start of many of these phenological periods is determined by snowmelt date, which may change in a changing climate. It has been suggested that the end of these periods during late-season are triggered by external cues, such as day length, light quality or temperature, leading to the hypothesis that earlier or later snowmelt dates will lengthen or shorten the duration of these periods, respectively, and thereby affect plant performance. We tested whether snowmelt date controls phenology and phenological period duration in High Arctic Svalbard using a melt timing gradient from natural and experimentally altered snow depths. We investigated the response of early- and late-season phenophases from both vegetative and reproductive phenological periods of eight common species. We found that all phenophases follow snowmelt patterns, irrespective of timing of occurrence, vegetative or reproductive nature. Three of four phenological period durations based on these phenophases were fixed for most species, defining the studied species as periodic. Periodicity can thus be considered an evolutionary trait leading to disadvantages compared with aperiodic species and we conclude that the mesic and heath vegetation types in Svalbard are at risk of being outcompeted by invading, aperiodic species from milder biomes.

  15. Spatial Vegetation Data for Gateway National Recreation Area Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Vegetation map of Gateway National Recreation Area provides local names for vegetation types, as well as crosswalks to the National Vegetation Classification System...

  16. Spatial Vegetation Data for Johnstown Flood National Memorial Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Vegetation map of Johnstown Flood National Memorial provides local park-specific names for vegetation types, as well as crosswalks to the National Vegetation...

  17. Influence of the type of vegetable oil on the drug release profile from lipid-core nanocapsules and in vivo genotoxicity study.

    Science.gov (United States)

    Rigo, Lucas Almeida; Frescura, Viviane; Fiel, Luana; Coradini, Karine; Ourique, Aline Ferreira; Emanuelli, Tatiana; Quatrin, Andréia; Tedesco, Solange; Silva, Cristiane B da; Guterres, Silvia Staniçuaski; Pohlmann, Adriana Raffin; Beck, Ruy Carlos Ruver

    2014-11-01

    The use of rice bran (RB), soybean (SB) or sunflower seed (SF) oils to prepare lipid-core nanocapsules (LNCs) as controlled drug delivery systems was investigated. LNCs were prepared by interfacial deposition using the preformed polymer method. All formulations showed negative zeta potential and adequate nanotechnological characteristics (particle size 220-230  nm, polydispersity index oils did not present genotoxic potential. Clobetasol propionate (CP) was selected as a model drug to evaluate the influence of the type of vegetable oil on the control of the drug release from LNCs. Biphasic drug release profiles were observed for all formulations. After 168  h, the concentration of drug released from the formulation containing SF oil was lower (0.36  mg/mL) than from formulations containing SB (0.40  mg/mL) or RB oil (0.45  mg/mL). Good correlations between the consistency indices for the LNC cores and the burst and sustained drug release rate constants were obtained. Therefore, the type of the vegetal oil was shown as an important factor governing the control of drug release from LNCs.

  18. Estimation of surface energy fluxes in the Arctic tundra using the remote sensing thermal-based Two-Source Energy Balance model

    Science.gov (United States)

    Cristóbal, Jordi; Prakash, Anupma; Anderson, Martha C.; Kustas, William P.; Euskirchen, Eugénie S.; Kane, Douglas L.

    2017-03-01

    The Arctic has become generally a warmer place over the past decades leading to earlier snow melt, permafrost degradation and changing plant communities. Increases in precipitation and local evaporation in the Arctic, known as the acceleration components of the hydrologic cycle, coupled with land cover changes, have resulted in significant changes in the regional surface energy budget. Quantifying spatiotemporal trends in surface energy flux partitioning is key to forecasting ecological responses to changing climate conditions in the Arctic. An extensive local evaluation of the Two-Source Energy Balance model (TSEB) - a remote-sensing-based model using thermal infrared retrievals of land surface temperature - was performed using tower measurements collected over different tundra types in Alaska in all sky conditions over the full growing season from 2008 to 2012. Based on comparisons with flux tower observations, refinements in the original TSEB net radiation, soil heat flux and canopy transpiration parameterizations were identified for Arctic tundra. In particular, a revised method for estimating soil heat flux based on relationships with soil temperature was developed, resulting in significantly improved performance. These refinements result in mean turbulent flux errors generally less than 50 W m-2 at half-hourly time steps, similar to errors typically reported in surface energy balance modeling studies conducted in more temperate climatic regimes. The MODIS leaf area index (LAI) remote sensing product proved to be useful for estimating energy fluxes in Arctic tundra in the absence of field data on the local biomass amount. Model refinements found in this work at the local scale build toward a regional implementation of the TSEB model over Arctic tundra ecosystems, using thermal satellite remote sensing to assess response of surface fluxes to changing vegetation and climate conditions.

  19. How does climate change influence Arctic mercury?

    Science.gov (United States)

    Stern, Gary A; Macdonald, Robie W; Outridge, Peter M; Wilson, Simon; Chételat, John; Cole, Amanda; Hintelmann, Holger; Loseto, Lisa L; Steffen, Alexandra; Wang, Feiyue; Zdanowicz, Christian

    2012-01-01

    Recent studies have shown that climate change is already having significant impacts on many aspects of transport pathways, speciation and cycling of mercury within Arctic ecosystems. For example, the extensive loss of sea-ice in the Arctic Ocean and the concurrent shift from greater proportions of perennial to annual types have been shown to promote changes in primary productivity, shift foodweb structures, alter mercury methylation and demethylation rates, and influence mercury distribution and transport across the ocean-sea-ice-atmosphere interface (bottom-up processes). In addition, changes in animal social behavior associated with changing sea-ice regimes can affect dietary exposure to mercury (top-down processes). In this review, we address these and other possible ramifications of climate variability on mercury cycling, processes and exposure by applying recent literature to the following nine questions; 1) What impact has climate change had on Arctic physical characteristics and processes? 2) How do rising temperatures affect atmospheric mercury chemistry? 3) Will a decrease in sea-ice coverage have an impact on the amount of atmospheric mercury deposited to or emitted from the Arctic Ocean, and if so, how? 4) Does climate affect air-surface mercury flux, and riverine mercury fluxes, in Arctic freshwater and terrestrial systems, and if so, how? 5) How does climate change affect mercury methylation/demethylation in different compartments in the Arctic Ocean and freshwater systems? 6) How will climate change alter the structure and dynamics of freshwater food webs, and thereby affect the bioaccumulation of mercury? 7) How will climate change alter the structure and dynamics of marine food webs, and thereby affect the bioaccumulation of marine mercury? 8) What are the likely mercury emissions from melting glaciers and thawing permafrost under climate change scenarios? and 9) What can be learned from current mass balance inventories of mercury in the Arctic? The

  20. Arctic ice management

    Science.gov (United States)

    Desch, Steven J.; Smith, Nathan; Groppi, Christopher; Vargas, Perry; Jackson, Rebecca; Kalyaan, Anusha; Nguyen, Peter; Probst, Luke; Rubin, Mark E.; Singleton, Heather; Spacek, Alexander; Truitt, Amanda; Zaw, Pye Pye; Hartnett, Hilairy E.

    2017-01-01

    As the Earth's climate has changed, Arctic sea ice extent has decreased drastically. It is likely that the late-summer Arctic will be ice-free as soon as the 2030s. This loss of sea ice represents one of the most severe positive feedbacks in the climate system, as sunlight that would otherwise be reflected by sea ice is absorbed by open ocean. It is unlikely that CO2 levels and mean temperatures can be decreased in time to prevent this loss, so restoring sea ice artificially is an imperative. Here we investigate a means for enhancing Arctic sea ice production by using wind power during the Arctic winter to pump water to the surface, where it will freeze more rapidly. We show that where appropriate devices are employed, it is possible to increase ice thickness above natural levels, by about 1 m over the course of the winter. We examine the effects this has in the Arctic climate, concluding that deployment over 10% of the Arctic, especially where ice survival is marginal, could more than reverse current trends of ice loss in the Arctic, using existing industrial capacity. We propose that winter ice thickening by wind-powered pumps be considered and assessed as part of a multipronged strategy for restoring sea ice and arresting the strongest feedbacks in the climate system.

  1. Arctic Climate Systems Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ivey, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Backus, George A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Peterson, Kara J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); van Bloemen Waanders, Bart G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Desilets, Darin Maurice [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reinert, Rhonda Karen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    This study began with a challenge from program area managers at Sandia National Laboratories to technical staff in the energy, climate, and infrastructure security areas: apply a systems-level perspective to existing science and technology program areas in order to determine technology gaps, identify new technical capabilities at Sandia that could be applied to these areas, and identify opportunities for innovation. The Arctic was selected as one of these areas for systems level analyses, and this report documents the results. In this study, an emphasis was placed on the arctic atmosphere since Sandia has been active in atmospheric research in the Arctic since 1997. This study begins with a discussion of the challenges and benefits of analyzing the Arctic as a system. It goes on to discuss current and future needs of the defense, scientific, energy, and intelligence communities for more comprehensive data products related to the Arctic; assess the current state of atmospheric measurement resources available for the Arctic; and explain how the capabilities at Sandia National Laboratories can be used to address the identified technological, data, and modeling needs of the defense, scientific, energy, and intelligence communities for Arctic support.

  2. The influence of soil type, vegetation cover and soil moisture on spin up behaviour of a land surface model in a monsoonal region

    Science.gov (United States)

    Bhattacharya, Anwesha; Mandal, Manabottam

    2015-04-01

    Model spin-up is the process through which the model is adequately equilibrated to ensure balance between the mass fields and velocity fields. In this study, an offline one dimensional Noah land surface model is integrated recursively for three years to assess its spin-up behavior at different sites over the Indian Monsoon domain. Several numerical experiments are performed to investigate the impact of soil category, vegetation cover, initial soil moisture and subsequent dry or wet condition on model spin-up. These include simulations with the dominant soil and vegetation covers of this region, different initial soil moisture content (observed soil moisture; dry soil; moderately wet soil; saturated soil), simulations initialized at different rain conditions (no rain; infrequent rain; continuous rain) and different seasons (Winter, Spring, Summer/Pre-Monsoon, Monsoon and Autumn). It is seen that the spin-up behavior of the model depends on the soil type and vegetation cover with soil characteristics having the larger influence. Over India, the model has the longest spin-up in the case of simulations with loamy soil covered with mixed-shrub. It is noted that the model has a significantly longer spin-up when initialized with very low initial soil moisture content than with higher soil moisture content. It is also seen that in general, simulations initialized just before a continuous rainfall event have the least spin-up time. This observation is reinforced by the results from the simulations initialized in different seasons. It is seen that for monsoonal region, the model spin-up time is least for simulations initialized just before the Monsoon. Model initialized during the Monsoon rain episodes has a longer spin-up than that initialized in any other season. Furthermore, it is seen that the model has a shorter spin-up if it reaches the equilibrium state predominantly via drying process and could be as low as two months under quasi-equilibrium condition depending on

  3. Presettlement Vegetation

    Data.gov (United States)

    Minnesota Department of Natural Resources — Presettlement vegetation of Minnesota based on Marschner's original analysis of Public Land Survey notes and landscape patterns. Marschner compiled his results in...

  4. Greening of the Arctic: Partitioning Warming Versus Reindeer Herbivory for Willow Populations on Yamal Peninsula, Northwest Siberia

    Science.gov (United States)

    Forbes, B. C.; Macias-Fauria, M.; Zetterberg, P.; Kumpula, T.

    2012-12-01

    Arctic warming has been linked to observed increases in tundra shrub cover and growth in recent decades on the basis of significant relationships between deciduous shrub growth/biomass and temperature. These vegetation trends have been linked to Arctic sea-ice decline and thus to the sea-ice/albedo feedback known as Arctic amplification. However, the interactions between climate, sea ice, tundra vegetation and herbivores remain poorly understood. Recently we revealed a 50-year growth response over a >100,000 km2 area to a rise in summer temperature for willow (Salix lanata), one the most abundant shrub genera at and north of the continental treeline and an important source of reindeer forage in spring, summer and autumn. We demonstrated that whereas plant productivity is related to sea ice in late spring, the growing season peak responds to persistent synoptic-scale air masses over West Siberia associated with Fennoscandian weather systems through the Rossby wave train. Substrate was important for biomass accumulation, yet a strong correlation between growth and temperature encompasses all observed soil types. Vegetation was especially responsive to temperature in early summer. However, the role of herbivory was not addressed. The present data set explores the relationship between long-term herbivory and growth trends of shrubs experiencing warming in recent decades. Semi-domestic reindeer managed by indigenous Nenets nomads occur at high densities in summer on exposed ridge tops and graze heavily on prostrate and low erect willows. A few meters away in moderately sloped landslides tall willows remain virtually ungrazed as their canopies have grown above the browse line of ca. 180 cm. Here we detail the responses of neighboring shrub populations with and without intensive herbivory yet subject to the same decadal warming trend.

  5. A Generic, Computer-assisted Method for Rapid Vegetation Classification and Survey: Tropical and Temperate Case Studies

    Directory of Open Access Journals (Sweden)

    Andrew N. Gillison

    2002-12-01

    Full Text Available Standard methods of vegetation classification and survey tend to be either too broad for management purposes or too reliant on local species to support inter-regional comparisons. A new approach to this problem uses species-independent plant functional types with a wide spectrum of environmental sensitivity. By means of a rule set, plant functional types can be constructed according to specific combinations from within a generic set of 35 adaptive, morphological plant functional attributes. Each combination assumes that a vascular plant individual can be described as a "coherent" functional unit. When used together with vegetation structure, plant functional types facilitate rapid vegetation assessment that complements species-based data and makes possible uniform comparisons of vegetation response to environmental change within and between countries. Recently developed user-friendly software (VegClass facilitates data entry and the analysis of biophysical field records from a standardized, rapid, survey pro forma. Case studies are presented at a variety of spatial scales and for vegetation types ranging from species-poor arctic tundra to intensive, multitaxa, baseline biodiversity assessments in complex, humid tropical forests. These demonstrate how such data can be rapidly acquired, analyzed, and communicated to conservation managers. Sample databases are linked to downloadable software and a training manual.

  6. Conflict Resolution Practices of Arctic Aboriginal Peoples

    NARCIS (Netherlands)

    R. Gendron; C. Hille

    2013-01-01

    This article presents an overview of the conflict resolution practices of indigenous populations in the Arctic. Among the aboriginal groups discussed are the Inuit, the Aleut, and the Saami. Having presented the conflict resolution methods, the authors discuss the types of conflicts that are current

  7. Arctic survey, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey and game patrol conducted to twelve villages in the Arctic from April 24 to May 2 1957. The report covers animals take for income and...

  8. Arctic Bathymetry (batharcst)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of the Arctic (North Pole area encircled by 640 N Latitude). The...

  9. Arctic Geology (geoarcst)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of the Arctic (North Pole area encircled by 640 N Latitude). The...

  10. Arctic_Bathymetry

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Models project the Arctic Ocean will become undersaturated with respect to carbonate minerals in the next decade. Recent field results indicate parts may already be...

  11. Vegetation type and age drive changes in soil properties, nitrogen and carbon sequestration in urban parks under cold climate

    Directory of Open Access Journals (Sweden)

    Heikki Martti Setälä

    2016-08-01

    Full Text Available Urban green spaces provide ecosystem properties fundamental to the provision of ecosystem services, such as the sequestration of carbon and nutrients and serving as a reservoir for organic matter. Although urban vegetation influences soil physico-chemical properties, it remains unknown whether ecosystem properties depend on plant species portfolios. We tested the influence of three common functional plant groups (evergreen trees, deciduous trees, grass/lawn for their ability to modify soils in parks of various ages under cold climatic conditions in Finland. We hypothesized that (i plant functional groups affect soils differently resulting in divergent ecosystem properties, and (ii that these ecosystem properties also depend on park age. We included 41 urban parks of varying ages (10, 50 and > 100 years and additional control forests. Park soils were sampled for physico-chemical parameters up to 50 cm depth. Our data indicate that plant functional groups modify soils differently, especially between the evergreen and lawn treatments at 50 and > 100 year old parks. Soils under evergreen trees had the lowest pH and generally the highest percentage organic matter, percentage total carbon and percentage total nitrogen. Soil pH remained the same, whereas concentrations of organic matter, total carbon and total nitrogen declined by depth. Soils in the reference forests had lower pH but higher percentages organic matter, total carbon and total nitrogen than those in parks. We estimate that old parks with evergreen trees can store 35.5 kg C m-2 and 2.3 kg N m-2 – considerably more than in urban soils in warmer climates. Our data suggest that plant-soil interactions in urban parks, in spite of being constructed environments, are surprisingly similar to those in natural forests.

  12. Enrichment Difference of Different Types of Vegetables to Heavy Metals%不同种类蔬菜对土壤重金属的富集差异

    Institute of Scientific and Technical Information of China (English)

    韩峰; 高雪; 陈海燕

    2014-01-01

    To explore the feasibility of planting vegetaldes on the land with heavy metal content above the national standard,a field contrast experiment was conducted to analyze the contents of heavy metals (Cd,Hg,As,Pb)in 12 vegetable variety samples planted in soils with heavy metals exceed standard,and the pollution levels were evaluated in the paper.The results indicated that cucumber had the strongest enrichment capacity for Cd,celery had the strongest enrichment capacity for Hg,all vegetables had weak enrichment capability on As and Pb.Single factor pollution index Cd in cucumber,cabbage,lettuce, radish and kidney beans were 3.260,3.140,2.900,2.520,and 1.900,respectively,which were moderate and above pollution level.Hg reached severe and above polluted in celery,radish,carrot,eggplant, lettuce loofah,and cabbage.Whereas,both As and Pb had no significant effect on quality in different vegetable varieties,which reached clean level.Therefore,it was suggested that under the detection of heavy metal contents in the soil,and according to the differences of heavy metal absorption in different vegetables,selectively plant different vegetables types to avoid the exceed of heavy metal contents,and to expand the planting areas of vegetables in Guizhou.%为探索重金属含量超标的耕地种植蔬菜的可行性,通过田间种植对比试验,分析了 Cd、Hg、As、Pb 超标土壤上12个蔬菜品种中的重金属含量,并对污染程度进行了评价。结果表明:黄瓜、芹菜分别对 Hg、Cd 的富集能力最强,各类蔬菜均对 As 和 Pb 富集能力较弱。黄瓜、大白菜、生菜、萝卜和棒豆中 Cd的单因子污染指数分别为3.260、3.140、2.900、2.520和1.900,达中度及以上污染水平;Hg 达到重度污染水平以上的蔬菜品种有芹菜、萝卜、胡萝卜、茄子、生菜、丝瓜和大白菜;As 和 Pb 均达清洁水平,对不同蔬菜品种质量均无显著影响。在 As、Pb

  13. Arctic Late Cretaceous and Paleocene Plant Community Succession

    Science.gov (United States)

    Herman, Alexei; Spicer, Robert; Daly, Robert; Jolley, David; Ahlberg, Anders; Moiseeva, Maria

    2010-05-01

    The Arctic abounds with Late Cretaceous and Paleocene plant fossils attesting to a thriving, diverse, but now extinct polar ecosystem that sequestered vast amounts of carbon. Through detailed examination of plant remains and their distributions in time and space with respect to their entombing sedimentary facies, it has been possible to reconstruct changes in Arctic vegetation composition and dynamics through the Late Cretaceous and into the Paleocene. Based on over 10,000 leaf remains, fossil wood and palynomorph assemblages from northeastern Russia and northern Alaska and palynological data from elsewhere in the Arctic we identify a number of successional plant communities (SPCs) representing seral development from early (pioneer), through middle to late SPCs and climax vegetation. We recognise that (1) Equisetites and some ferns (typically Birisia, but after the beginning of the Maastrichtian, Onoclea) were obligatory components of the early SPCs; (2) first rare angiosperms (e.g. the dicot Vitiphyllum multifidum) appeared in the middle SPCs of the Arctic in the Early - Middle Albian; (3) from late Albian times onwards angiosperms became abundant in the middle SPCs of the Arctic, but were still rare in the earlier and later SPCs; (4) monocots appeared in the Maastrichtian early SPCs; (5) all Arctic Cretaceous late SPCs (and climax vegetation) were dominated by conifers; (6) Arctic SPCs were more numerous and diverse under warm climates than cold; (7) during the Albian and late Cretaceous, advanced (Cenophytic, angiosperm-dominated) plant communities coexisted with those of a more relictual (Mesophytic, dominated by ferns and gymnosperms) aspect, and plants composing these communities did not mix; (8) coal-forming environments (mires) remained conifer, fern and bryophyte dominated throughout the late Cretaceous and Paleocene with little penetration of woody angiosperm components and thus are conservative and predominantly Mesophytic in character; (9) bryophytes

  14. Enabling Use of Unmanned Aircraft Systems for Arctic Environmental Monitoring

    DEFF Research Database (Denmark)

    Storvold, Rune; la Cour-Harbo, Anders; Mulac, Brenda;

    , satellites and manned aircraft are the traditional platforms on which scientists gather data of the atmosphere, sea ice, glaciers, fauna and vegetation. However, significant data gaps still exist over much of the Arctic because there are few research stations, satellites are often hindered by cloud cover......, poor resolution, and the complicated surface of snow and ice. Measurements made from manned aircraft are also limited because of range and endurance, as well as the danger and costs presented by operating manned aircraft in harsh and remote environments like the Arctic. Unmanned aircraft systems (UAS...

  15. Arctic hydrology and meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D.L.

    1989-01-01

    To date, five years of hydrologic and meteorologic data have been collected at Imnavait Creek near Toolik Lake, Alaska. This is the most complete set of field data of this type collected in the Arctic of North America. These data have been used in process-oriented research to increase our understanding of atmosphere/hydrosphere/biosphere/lithosphere interactions. Basically, we are monitoring heat and mass transfer between various spheres to quantify rates. These could be rates of mass movement such as hillslope flow or rates of heat transfer for active layer thawing or combined heat and mass processes such as evapotranspiration. We have utilized a conceptual model to predict hydrologic processes. To test the success of this model, we are comparing our predicted rates of runoff and snowmelt to measured valves. We have also used a surface energy model to simulate active layer temperatures. The final step in this modeling effort to date was to predict what impact climatic warming would have on active layer thicknesses and how this will influence the hydrology of our research watershed by examining several streambeds.

  16. Arctic Collaborative Environment (ACE)

    Science.gov (United States)

    2012-08-01

    distribution is unlimited. Key Data Requirements • Sea Ice – Location: Area, Onset, Growth, Drift, and Decay – Characterization: % Coverage, Thickness...Cloud ACE Developmental Server hosted at UAHuntsville ACE User Community Public Internet Tailored Ice Product Generation (NIC) Arctic Research...distribution is unlimited. Arctic Map 26 July 2012 13 Multi-sensor Analyzed Sea Ice Extent; National Data Buoy Center DISTRIBUTION STATEMENT A

  17. Death of an Arctic Mixed Phase Cloud: How Changes in the Arctic Environment Influence Cloud Properties and Cloud Radiative Feedbacks

    Science.gov (United States)

    Roesler, E. L.; Posselt, D. J.

    2012-12-01

    Arctic mixed phase stratocumulus clouds exert an important influence on the radiative budget over the Arctic ocean and sea ice. Field programs and numerical experiments have shown the properties of these clouds to be sensitive to changes in the surface properties, thermodynamic environment, and aerosols. While it is clear that Arctic mixed-phase clouds respond to changes in the Arctic environment, uncertainty remains as to how climate warming will affect the cloud micro- and macrophysical properties. This is in no small part due to the fact that there are nonlinear interactions between changes in atmospheric and surface properties and changes in cloud characteristics. In this study, large-eddy simulations are performed of an arctic mixed phase cloud observed during the Indirect and Semi-Direct Aerosol Campaign. A parameter-space-filling uncertainty quantification technique is used to rigorously explore how simulated arctic mixed phase clouds respond to changes in the properties of the environment. Specifically, the cloud ice and aerosol concentration, surface sensible and latent heat fluxes, and large scale temperature, water vapor, and vertical motion are systematically changed, and the properties of the resulting clouds are examined. It is found that Arctic mixed phase clouds exhibit four characteristic behaviors: stability, growth, decay, and dissipation. Sets of environmental and surface properties that lead to the emergence of each type of behavior are presented, and the implications for the response of Arctic clouds to changes in climate are explored.

  18. Arctic freshwater synthesis: Introduction

    Science.gov (United States)

    Prowse, T.; Bring, A.; Mârd, J.; Carmack, E.

    2015-11-01

    In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program, an updated scientific assessment has been conducted of the Arctic Freshwater System (AFS), entitled the Arctic Freshwater Synthesis (AFSΣ). The major reason for joint request was an increasing concern that changes to the AFS have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra-Arctic climatic effects that will have global consequences. Hence, the key objective of the AFSΣ was to produce an updated, comprehensive, and integrated review of the structure and function of the entire AFS. The AFSΣ was organized around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources and modeling, and the review of each coauthored by an international group of scientists and published as separate manuscripts in this special issue of Journal of Geophysical Research-Biogeosciences. This AFSΣ—Introduction reviews the motivations for, and foci of, previous studies of the AFS, discusses criteria used to define the domain of the AFS, and details key characteristics of the definition adopted for the AFSΣ.

  19. Monitoring of Arctic Conditions from a Virtual Constellation of Synthetic Aperture Radar Satellites

    Science.gov (United States)

    2014-09-30

    radars to monitor the melting and freezing cycles of the Arctic Ocean north of 65o. Satellite data collections will support in-situ buoy clusters and... ice -type, and lead expansion/contraction with temporal resolutions from hours to days. Ultimately provide a routine Arctic coverage and generate...OBJECTIVES a) Provide daily Arctic situational awareness from the CSTARS SAR satellite constellation. b) Develop a Neural Network algorithm for ice -type

  20. CHARACTERIZATION OF THE TYPE AND EXTENT OF NUTRIENT LIMITATION IN GRASSLAND VEGETATION USING A BIOASSAY WITH INTACT SODS

    NARCIS (Netherlands)

    OLFF, H; PEGTEL, DM

    1994-01-01

    An important methodological problem in plant ecology concerns the way in which the type and extent of nutrient limitation in terrestrial communities should be assessed. Conclusions on nutrient limitation have been founded mainly on soil extractions, fertiliser trials and tissue nutrient concentratio

  1. Response of Coprophagus Beetles (Coleoptera: Scarabaeidae on changes of vegetation structure in various habitat types at Lore Lindu National Park, Central Sulawesi

    Directory of Open Access Journals (Sweden)

    CHRISTIAN H. SCHULZE

    2007-01-01

    Full Text Available This study analysed the response of dung beetles − a group of beetles which play a major role in decomposition of dung and animal carcasses − to changes of vegetation structure due to forest conversion to different human-made habitat types at the margin of Lore Lindu National Park. Therefore, dung beetles were sampled at natural forest, cacao agroforestry systems and open area. A total of 28 species of coprophagus beetle species were recorded from the sampled sites. Species richness and abundance of dung beetles, particularly of large species, decreased from forest towards agroforestry systems and open areas. However, more than 80 % of the species recorded in natural forest were found in cacao agroforestry systems Of the measured habitat parameters, particularly the number of tree species, air temperature, and canopy cover had a significant power for explaining changes in dung beetle ensembles along the gradient of land-use intensity.

  2. Analyses on types and characteristics of community of urban semi-natural vegetation in Urumqi%乌鲁木齐城市半自然植被群落类型及特征分析

    Institute of Scientific and Technical Information of China (English)

    南伟疆; 昝勤; 姜逢清; 王蕾; 严成; 尹林

    2011-01-01

    Based on previous study results and combined with investigation of typical sampling plots,community types of urban semi-natural vegetation in Urumqi were classified, and characteristics of community structure, species composition and plant growth-form spectrum were analyzed. The results show that types of urban semi-natural vegetation in Urumqi can be divided into four vegetation races,thirty-three vegetation types and thirty-eight association groups. In which, broadleaved forest vegetation race includes eight vegetation types and eleven association groups; shrub vegetation race does twelve vegetation types and twelve association groups; herb vegetation race does ten vegetation types and eleven association groups; vegetation race associated with human does three vegetation types and four association groups. The number of vegetation types and association groups in shrub vegetation race are the most,while those in vegetation race associated with human are the fewest. In the urban semi-natural vegetation community, the synusium of broadleaved forest vegetation race are two- and three- layers, that of shrub vegetation race mainly two-layer, those of herb vegetation race and vegetation race associated with human one-layer. The synusium types mainly are single herb type, arbor-shrub type and shrub-herb type. There are eighty-eight species of spermatophyte belonging to seventy-four genera of twenty-four families in the urban semi-natural vegetation community, the dominant families are Gramineae, Chenopodiaceae,Leguminosae, Compositae, Rosaceae and Cruciferae, containing forty-seven genera and fifty-seven species accounting for 63.51% and 64.77% of total number of genera and species of spermatophyte respectively in the community. In the community, annual and perennial herbs and perennial semishrub species are more with a percentage of 29.55%, 34.10% and 17.04% of total species, respectively.According to related results, the differences between the urban semi

  3. Trajectory of the Arctic as an integrated system.

    Science.gov (United States)

    Hinzman, Larry D; Deal, Clara J; McGuire, A David; Mernild, Sebastian H; Polyakov, Igor V; Walsh, John E

    2013-12-01

    Although much remains to be learned about the Arctic and its component processes, many of the most urgent scientific, engineering, and social questions can only be approached through a broader system perspective. Here, we address interactions between components of the Arctic system and assess feedbacks and the extent to which feedbacks (1) are now underway in the Arctic and (2) will shape the future trajectory of the Arctic system. We examine interdependent connections among atmospheric processes, oceanic processes, sea-ice dynamics, marine and terrestrial ecosystems, land surface stocks of carbon and water, glaciers and ice caps, and the Greenland ice sheet. Our emphasis on the interactions between components, both historical and anticipated, is targeted on the feedbacks, pathways, and processes that link these different components of the Arctic system. We present evidence that the physical components of the Arctic climate system are currently in extreme states, and that there is no indication that the system will deviate from this anomalous trajectory in the foreseeable future. The feedback for which the evidence of ongoing changes is most compelling is the surface albedo-temperature feedback, which is amplifying temperature changes over land (primarily in spring) and ocean (primarily in autumn-winter). Other feedbacks likely to emerge are those in which key processes include surface fluxes of trace gases, changes in the distribution of vegetation, changes in surface soil moisture, changes in atmospheric water vapor arising from higher temperatures and greater areas of open ocean, impacts of Arctic freshwater fluxes on the meridional overturning circulation of the ocean, and changes in Arctic clouds resulting from changes in water vapor content.

  4. Seasonal variation and controlling factors of soil carbon effluxes in six vegetation types in southeast of Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern (Dept. of Physical Geography and Ecosystem Analysis, Lund Univ., Lund (SE))

    2007-11-15

    Soil carbon effluxes of a pine stand, a spruce stand, a lichen rock, two oak stands and a meadow in the Laxemar investigation area in south-eastern Sweden (57 deg 5 N, 16 deg 7 E) have been measured with the closed chamber technique at 14 occasions between 23 of March 2004 and 10th of March 2005. Soil temperature at 10 cm depth, air temperature, soil moisture and photosynthetically active radiation (PAR) were also measured. Exponential regressions with soil respiration against air and soil temperature were used to estimate soil respiration between 15th of March 2004 and 14th of March 2005. A light response curve with Gross Primary Production (GPP) against PAR and a cubic regression with GPP against air temperature were used for modelling GPP in meadow for the growing season, 15th of March to 31st of October 2004. The exponential regressions with soil respiration against air and soil temperature explained on average 30.6% and 47.6% of the variation, respectively. Soil moisture had a linear limiting effect on soil respiration for all ecosystems but spruce, where soil moisture was the limiting factor above a threshold value of about 50%vol. In the forest ecosystems, GPP of the ground vegetation were not reducing soil carbon effluxes, while in meadow it was. In meadow, the light response curve with GPP against PAR explained 32.7% of the variation in GPP while the cubic regression against air temperature explained 33.9%. No significant effect of soil moisture on GPP was detected. The exponential regression equations with air and soil temperature against soil respiration could be used to temporally extrapolate the occasional field measurements. The light response curve with GPP against PAR and the cubic regression with GPP against air temperature could also be used for temporal extrapolation. From the modelled soil respiration, annual soil respiration for the ecosystems in Laxemar, during 15th of March 2004 to 14th of March 2005, were estimated to be between 0.56 and 1

  5. Exposure of trees to drought-induced die-off is defined by a common climatic threshold across different vegetation types.

    Science.gov (United States)

    Mitchell, Patrick J; O'Grady, Anthony P; Hayes, Keith R; Pinkard, Elizabeth A

    2014-04-01

    Increases in drought and temperature stress in forest and woodland ecosystems are thought to be responsible for the rise in episodic mortality events observed globally. However, key climatic drivers common to mortality events and the impacts of future extreme droughts on tree survival have not been evaluated. Here, we characterize climatic drivers associated with documented tree die-off events across Australia using standardized climatic indices to represent the key dimensions of drought stress for a range of vegetation types. We identify a common probabilistic threshold associated with an increased risk of die-off across all the sites that we examined. We show that observed die-off events occur when water deficits and maximum temperatures are high and exist outside 98% of the observed range in drought intensity; this threshold was evident at all sites regardless of vegetation type and climate. The observed die-off events also coincided with at least one heat wave (three consecutive days above the 90th percentile for maximum temperature), emphasizing a pivotal role of heat stress in amplifying tree die-off and mortality processes. The joint drought intensity and maximum temperature distributions were modeled for each site to describe the co-occurrence of both hot and dry conditions and evaluate future shifts in climatic thresholds associated with the die-off events. Under a relatively dry and moderate warming scenario, the frequency of droughts capable of inducing significant tree die-off across Australia could increase from 1 in 24 years to 1 in 15 years by 2050, accompanied by a doubling in the occurrence of associated heat waves. By defining commonalities in drought conditions capable of inducing tree die-off, we show a strong interactive effect of water and high temperature stress and provide a consistent approach for assessing changes in the exposure of ecosystems to extreme drought events.

  6. Dissolved inorganic nitrogen pools and surface flux under different brackish marsh vegetation types, common reed (Phragmites australis) and salt hay (Spartina patens)

    Science.gov (United States)

    Windham-Myers, L.

    2005-01-01

    The current expansion of Phragmites australis into the high marsh shortgrass (Spartina patens, Distichlis spicata) communities of eastern U.S. salt marshes provided an opportunity to identify the influence of vegetation types on pools and fluxes of dissolved inorganic nitrogen (DIN). Two brackish tidal marshes of the National Estuarine Research Reserve system were examined, Piermont Marsh of the Hudson River NERR in New York and Hog Island in the Jacques Coustaeu NERR of New Jersey. Pools of DIN in porewater and rates of DIN surface flux were compared in replicated pairs of recently-expanded P. australis and neighboring S. patens-dominated patches on the high marsh surface. Both marshes generally imported nitrate (NO3-) and exported ammonium (NH4+), such that overall DIN was exported. No differences in surface exchange of NO3- or NH4+ were observed between vegetation types. Depth-averaged porewater NH4+ concentrations over the entire growing season were 56% lower under P. australis than under S. patens (average 1.4 vs. 3.2 mg NH4+ L-1) with the most profound differences in November. Porewater profiles showed an accumulation of NH4+ at depth in S. patens and constant low concentrations in P. australis from the soil surface to 50 cm depth, with no significant differences in porewater salinity. Despite these profound differences in porewater, NH 4+ diffusion from soils of P. australis and S. patens were not measurably different, were similar to other published rates, and were well below estimated rates based on passive diffusion alone. Rapid adsorption and uptake by litter and microbes in surface soils of both communities may buffer NH4+ loss to flooding tides in both communities, thereby reducing the impact of P. australis invasion on NH4+ flux to flooding waters. ?? Springer 2005.

  7. Non-free ionic transport of sodium, magnesium, and calcium in streams of two adjacent headwater catchments with different vegetation types in Japan

    Science.gov (United States)

    Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

    2017-01-01

    Sodium (Na), magnesium (Mg), calcium (Ca) are usually believed to occur mostly as free ions in the fresh water and consequently little is known about their chemical species. To understand the importance of non-free ionic fractions (NIF) of major metals in freshwater streams, Na, Mg, Ca, silicon (Si), and fulvic acid-like materials (FAM) were measured in streams of mountainous adjacent headwater catchments dominated by different vegetation types (planted evergreen coniferous forest and natural deciduous broadleaf forest). During both no rainfall periods and rainstorms, the proportion of NIF relative to total elements was lower in the coniferous catchment than in the deciduous catchment, although it sometimes accounted for half or more of the total concentrations of Na, Mg, and Ca in both catchments. The solubility of metal compounds was higher than the measured maximum concentrations of Na+, Mg2+, and Ca2+ to the extent that inorganic bonding was hardly possible. During no rainfall periods when FAM was slightly produced into the streams, the fluxes of NIF and Si were highly correlated (r > 0.92, p NIF correlated weakly with that of Si but did not correlate with that of FAM in both catchments. In contrast, during a heavy rainstorm, the flux of NIF correlated strongly (r ⩾ 0.83, p NIF originated in the quick-flow component (i.e., surface or near-surface water) in stream water (ΔNIF) correlated strongly (r ⩾ 0.81, p < 0.0001, n = 22) with that of FAM. These findings imply that heavy rainstorms may enhance the bonding of the major metals with humic substances mainly in the deciduous catchment; and also exhibit that, in the headwater catchments, both water flow pathways resulted from the different vegetation types play a very important role to promote the bonding of major metals with humic substances in stream water.

  8. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    OpenAIRE

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-01-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the p...

  9. Atmospheric heat transfer to the Arctic under main synoptic processes

    Science.gov (United States)

    Yurova, Alla; Gnatiuk, Natalia; Bobylev, Leonid; Zhu, Yali

    2016-04-01

    Arctic - mid-latitude teleconnections are operating in both ways and behind them are potentially some causes of the enhanced Arctic warming (e.g., through heat transfer from lower to higher latitudes) and the feedbacks from the Arctic climate to the mid-latitude weather patterns. In order to explain the variability of the surface air temperature in the Arctic, we aim to analyse the typical synoptic situations that, we hypothesize, are characterized by a specific patterns of heat exchange between the Arctic and mid-latitudes. According to classification of synoptic processes in the Arctic developed at the Arctic and Antarctic Research Institute (AARI) in St. Petersburg major typical groups of synoptic situations in the Arctic are few (six). They correspond to position and intensity of low- and high-pressure centres. Therefore, the whole data sample for the winter period for the entire period of instrumental observations (archive exists back to 1939) can be split into six groups that sub-sample each of six groups/types of synoptic situations. Then heat transfer to the Arctic can be estimated as the divergence of the horizontal (advective) heat flux (the product of wind speed and temperature gradient) within each vertical atmospheric layer, which is calculated based on the ERA Interim Reanalysis data for the winter season (1979-now). Mapping heat divergence fields will reveal the main mid-latitude sources of heat transported to the Arctic, average for the whole data sample and for each of the six main groups of synoptic situations. This work was supported by RFBR grants 16-55-53031

  10. A comparison of annual and seasonal carbon dioxide effluxes between subarctic Sweden and high-arctic Svalbard

    DEFF Research Database (Denmark)

    Björkman, Mats P.; Morgner, Elke; Björk, Robert G.;

    2010-01-01

    effluxes between snow regimes or vegetation types, indicating that spatial variability in winter soil CO2 effluxes are not directly linked to snow cover thickness or soil temperatures. Total winter emissions (0.004– 0.248 kg CO2 m–2) were found to be in the lower range of those previously described......Recent climate change predictions suggest altered patterns of winter precipitation across the Arctic. It has been suggested that the presence, timing and quantity of snow all affect microbial activity, thus influencing CO2 production in soil. In this study annual and seasonal emissions of CO2 were...... in order to evaluate the effect of snow depth on winter CO2 effluxes. Total annual emissions of CO2 from the sub-Arctic site (0.662–1.487 kg CO2 m–2 yr–1) were found to be more than double the emissions from the High-Arctic site (0.369–0.591 kg CO2 m–2 yr–1). There were no significant differences in winter...

  11. Mercury mobilisation from soils and ashes after a wildfire and rainfall events: effects of vegetation type and fire severity

    Science.gov (United States)

    Campos, Isabel; Abrantes, Nelson; Keizer, Jan Jacob; Vale, Carlos; Serpa, Dalila; Pereira, Patrícia

    2016-04-01

    Wildfire is a major disturbance of forests worldwide, with huge environmental impacts. The number of catastrophic wildfires is increasing over the past few decades mainly due to a combined effect of climate change and poor land-use management. Interestingly, wildfires have an important role in contaminants production and mobilization and, thus, on their biogeochemical cycles. For instance, trace elements could be mobilized during a wildfire from burnt vegetation and ashes and may eventually achieve the aquatic systems upon a rainfall period. In this regard, wildfires represent a relevant diffuse source of trace elements to aquatic systems that has, so far, been poorly investigated. The current study aims to mitigate such lack of knowledge for mercury, a well-recognized persistent toxicant with potential harmful impacts on the environment and on human health. Thus, a field study was conducted in two Portuguese forests (Ermida and S. Pedro do Sul, North-centre of Portugal) with distinct fire severity. Fire was classified as moderate in Ermida and moderate to high severity in S. Pedro do Sul. In Ermida, soil samples and ashes were collected in the seven hillslopes (three burnt eucalypt, three burnt pine and one unburnt eucalypt) immediately and 4 months after the fire, the latter following an episode of intense rainfall. In S. Pedro do Sul, sampling took place immediately after the fire in four hillslopes (one burnt eucalypt and three burnt pine). Mercury analysis was performed in an Hg analyser in which samples were thermally decomposed by controlled heating. The final decomposition products were passed through an Hg amalgamator heated to 700 °C and Hg(0) was released and detected by absorption spectrometry at 254 nm. Burnt soil samples showed significantly lower levels of mercury than non-burnt soil, confirming the potential of a forest fire to release accumulated mercury in soil prior to the burning. Such process could be particularly relevant for this element due

  12. Arctic Rabies – A Review

    Directory of Open Access Journals (Sweden)

    Prestrud Pål

    2004-03-01

    Full Text Available Rabies seems to persist throughout most arctic regions, and the northern parts of Norway, Sweden and Finland, is the only part of the Arctic where rabies has not been diagnosed in recent time. The arctic fox is the main host, and the same arctic virus variant seems to infect the arctic fox throughout the range of this species. The epidemiology of rabies seems to have certain common characteristics in arctic regions, but main questions such as the maintenance and spread of the disease remains largely unknown. The virus has spread and initiated new epidemics also in other species such as the red fox and the racoon dog. Large land areas and cold climate complicate the control of the disease, but experimental oral vaccination of arctic foxes has been successful. This article summarises the current knowledge and the typical characteristics of arctic rabies including its distribution and epidemiology.

  13. BRDF characteristics of tundra vegetation communities in Yamal, Western Siberia

    Science.gov (United States)

    Buchhorn, Marcel; Heim, Birgit; Walker, Donald A. Skip; Epstein, Howard; Leibman, Marina

    2013-04-01

    (NASA Yamal-LCLUC) transects and réleves at Laboravaya (southern Yamal) and Vaskiny Dachi (central Yamal), and at the Circumpolar Active Layer Monitoring (CALM) site in Vaskiny Dachi. The LCLUC plots are Greening of the Arctic (GOA) sites established in 2007 by Walker et al. (2009). The Circumpolar Active Layer Monitoring (CALM) site was established by M. Leibman (ECI) in 1993. BRDF processing for the tundra test sites demonstrate the mirror asymmetry in relative azimuth with respect to the principal plane. It also showed that the maximum scattering appears in the backward direction, but that there is no minimal forward scattering. Instead, the forward scattering is characterized by similar to higher reflectance values compared to the nadir position. Moreover, the analysis of the anisotropic behaviour of moss-dominated tundra types with 10 to 15% vascular plant cover show that the BRDF influence on vegetation indices (VI) of low-growing arctic vegetation communities can be up to 15% of the nadir value. The low sun elevation at the arctic latitudes prevents hotspot-effects, but a BRDF normalization still should be taken into account for the development of tundra-adapted vegetation indices. Walker, D.A. et al. (2009): Data Report of the 2007 and 2008 Yamal Expeditions. AGC Data Report. 133.

  14. Vegetation survey of Sengwa

    Directory of Open Access Journals (Sweden)

    G. C. Craig

    1983-12-01

    Full Text Available The approach and initial results of a vegetation survey of the Sengwa Wildlife Area are outlined. The objectives were to produce a vegetation classification and map sufficiently detailed to serve as a base for the management of the natural vegetation. The methods adopted consist of (a stratification of the area into homogeneous units using 1:10 000 colour aerial photographs; (b plotless random sampling of each stratum by recording cover abundance on the Braun-Blaunquet scale for all woody species; and (c analysis of the data by indicator species analysis using the computer programme 'Twinspan’. The classification produced is successful in achieving recognizable vegetation types which tie in well with known environmental features.

  15. Climate of the Arctic marine environment.

    Science.gov (United States)

    Walsh, John E

    2008-03-01

    The climate of the Arctic marine environment is characterized by strong seasonality in the incoming solar radiation and by tremendous spatial variations arising from a variety of surface types, including open ocean, sea ice, large islands, and proximity to major landmasses. Interannual and decadal-scale variations are prominent features of Arctic climate, complicating the distinction between natural and anthropogenically driven variations. Nevertheless, climate models consistently indicate that the Arctic is the most climatically sensitive region of the Northern Hemisphere, especially near the sea ice margins. The Arctic marine environment has shown changes over the past several decades, and these changes are part of a broader global warming that exceeds the range of natural variability over the past 1000 years. Record minima of sea ice coverage during the past few summers and increased melt from Greenland have important implications for the hydrographic regime of the Arctic marine environment. The recent changes in the atmosphere (temperature, precipitation, pressure), sea ice, and ocean appear to be a coordinated response to systematic variations of the large-scale atmospheric circulation, superimposed on a general warming that is likely associated with increasing greenhouse gases. The changes have been sufficiently large in some sectors (e.g., the Bering/Chukchi Seas) that consequences for marine ecosystems appear to be underway. Global climate models indicate an additional warming of several degrees Celsius in much of the Arctic marine environment by 2050. However, the warming is seasonal (largest in autumn and winter), spatially variable, and closely associated with further retreat of sea ice. Additional changes predicted for 2050 are a general decrease of sea level pressure (largest in the Bering sector) and an increase of precipitation. While predictions of changes in storminess cannot be made with confidence, the predicted reduction of sea ice cover will

  16. Arctic dimension of global warming

    Directory of Open Access Journals (Sweden)

    G. V. Alekseev

    2014-01-01

    Full Text Available A brief assessment of the global warming in the Arctic climate system with the emphasis on sea ice is presented. The Arctic region is coupled to the global climate system by the atmosphere and ocean circulation that providesa major contribution to the Arctic energy budget. On this basis using of special indices it is shown that amplification of warming in the Arctic is associated with the increasing of meridional heat transport from the low latitudes.

  17. Airborne Spectral BRDF of Various Surface Types (Ocean, Vegetation, Snow, Desert, Wetlands, Cloud Decks, Smoke Layers) for Remote Sensing Applications

    Science.gov (United States)

    Gatebe, Charles K.; King, Michael D.

    2016-01-01

    In this paper we describe measurements of the bidirectional reflectance-distribution function (BRDF) acquired over a 30-year period (1984-2014) by the National Aeronautics and Space Administration's (NASA's) Cloud Absorption Radiometer (CAR). Our BRDF database encompasses various natural surfaces that are representative of many land cover or ecosystem types found throughout the world. CAR's unique measurement geometry allows a comparison of measurements acquired from different satellite instruments with various geometrical configurations, none of which are capable of obtaining such a complete and nearly instantaneous BRDF. This database is therefore of great value in validating many satellite sensors and assessing corrections of reflectances for angular effects. These data can also be used to evaluate the ability of analytical models to reproduce the observed directional signatures, to develop BRDF models that are suitable for sub-kilometer-scale satellite observations over both homogeneous and heterogeneous landscape types, and to test future spaceborne sensors. All of these BRDF data are publicly available and accessible in hierarchical data format (http:car.gsfc.nasa.gov/).

  18. Acquatorialities of the Arctic Region

    DEFF Research Database (Denmark)

    Harste, Gorm

    2013-01-01

    In order to describe the Arctic system I propose using a concept functionally equivalent to territoriality, namely aquatoriality. Whether communicating about territoriality or aquatoriality, concepts and delimitations are both contingent to forms of communication systems. I will distinguish betwe...... coding of the Arctic. These codes could then appear structurally coupled to a political system that in an organizational way appears in the Arctic Council...

  19. Kuchler Vegetation

    Data.gov (United States)

    California Department of Resources — Digital version of potential natural plant communites as compiled and published on 'Map of the Natural Vegetation of California' by A. W. Kuchler, 1976. Source map...

  20. Arctic security and Norway

    Energy Technology Data Exchange (ETDEWEB)

    Tamnes, Rolf

    2013-03-01

    Global warming is one of the most serious threats facing mankind. Many regions and countries will be affected, and there will be many losers. The earliest and most intense climatic changes are being experienced in the Arctic region. Arctic average temperature has risen at twice the rate of the global average in the past half century. These changes provide an early indication for the world of the environmental and societal significance of global warming. For that reason, the Arctic presents itself as an important scientific laboratory for improving our understanding of the causes and patterns of climate changes. The rapidly rising temperature threatens the Arctic ecosystem, but the human consequences seem to be far less dramatic there than in many other places in the world. According to the U.S. National Intelligence Council, Russia has the potential to gain the most from increasingly temperate weather, because its petroleum reserves become more accessible and because the opening of an Arctic waterway could provide economic and commercial advantages. Norway might also be fortunate. Some years ago, the Financial Times asked: #Left Double Quotation Mark#What should Norway do about the fact that global warming will make their climate more hospitable and enhance their financial situation, even as it inflicts damage on other parts of the world?#Right Double Quotation Mark#(Author)

  1. More Arctic research needed

    Science.gov (United States)

    Bush, Susan

    The desire to achieve a balance between Arctic and Antarctic study was the message of the Senate Committee on Commerce, Science, and Transportation, which heard testimony on the need for more Arctic research on April 24. Ted Stevens (R-Alaska) noted that since 1986, study in the area has not increased as the National Science Foundation has claimed, but rather, owing to inflation, has merely kept pace. Robert Correll, assistant director of geosciences at NSF and chair of the Interagency Arctic Oceans Working Group, gave several reasons why the Arctic is an important area for study by the scientific community. Its unique environment, he said, makes it a natural laboratory. And due to its environmental sensitivity, it may provide one of the earliest indicators of global climate change. Also, its geographic location makes it a “window on space,” some of the world's largest mineral and petroleum resources are in the Arctic, and the region has great strategic and military importance.

  2. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian; N. Mikkelsen, Teis; Ro-Poulsen, Helge

    -B was demonstrated to decrease photosynthesis and shift carbon allocation from shoots to roots. Moreover, ambient UV-B increased plant stress with detrimental effects on electron processing in the photosynthetic apparatus. Plant responses did not lead to clear changes in the amount of fungal root symbionts...... on high-arctic vegetation. They supplement previous investigations from the Arctic focussing on other variables like growth etc., which have reported no or minor plant responses to UV-B, and clearly indicates that UV-B radiation is an important factor affecting plant life at high-arctic Zackenberg...

  3. Diversity and Impacts of Mining on the Non-Volant Small Mammal Communities of Two Vegetation Types in the Brazilian Amazon

    Science.gov (United States)

    Ardente, Natália Carneiro; Ferreguetti, Átilla Colombo; Gettinger, Donald; Leal, Pricila; Mendes-Oliveira, Ana Cristina; Martins-Hatano, Fernanda; Bergallo, Helena Godoy

    2016-01-01

    The Carajás National Forest contains some of the largest iron ore deposits in the world. The majority of the minerals are found below a plant community known as Savana Metalófila, or “Canga”, which represents only 3% of the landscape within the Carajás National Forest (CNF). The aim of our study was to understand the diversity of community of non-volant small mammals in the two predominant vegetation types: Ombrophilous Forest and Canga, and to examine how mining impacts these communities. Sampling was conducted from January 2010 to August 2011 in 11 sampling sites divided by the total area of Canga and 12 sampling sites in the forest, totalizing 23 sites. Of these, 12 sites (Canga and Forest) were considered impacted areas located close to the mine (<< 900 meters) and 11 sites (Canga and Forest), serving as controls, which were at least 7,000 meters from the mine. We recorded 28 species, 11 from the Order Didelphimorphia and 17 from the Order Rodentia. The two forest types shared 68.42% of the species found in the CNF. A gradient analysis (Non-metric multidimensional scaling) revealed that the first axis clearly separated the non-flying small mammal communities by vegetation type. Occupancy models showed that the detectability of species was affected by the distance from the mining activities. Of all the small mammals analyzed, 10 species were positively affected by the distance from mining in areas impacted (e.g. more likely to be detected farther from mining areas) and detectability was lower in impacted areas. However, three species were negatively affected by the distance from mining, with higher detectability in the impacted areas, and seven species showed no effect of their proximity to mining operations. To date, there are no studies in Brazil about the impact of mining on mammals or other vertebrates. This study reveals that the effect of mining may go beyond the forest destruction caused by the opening of the mining pits, but also may negatively

  4. Application of 3S Techniques in Vegetation Type Investigation in Yajiang%基于3S技术的雅江县植被类型调查与分析

    Institute of Scientific and Technical Information of China (English)

    刘中正; 彭培好; 周正坤

    2013-01-01

    使用TM遥感影像,借助GIS软件进行了影像的处理和解译;制作了植被类型图,计算主要植被类型的面积及其变化情况;分析了3S技术在植被调查中的优势,并调查了植被动态变化,为植被恢复模式的建立提供了依据.%Based on the data available and using the GIS software, we processed and interpreted the Remote Sensing images composed by TM. And we also made the vegetation type chart, in order to calculate the vegetation type area and its change. In this thesis, we explored the advantages of 3S techniques in vegetation investigation and found the dynamic changes in vegetation type area, so as to lay the foundation for building vegetation restoration mode.

  5. Habitat-specific effects of climate change on a low-mobility Arctic spider species

    DEFF Research Database (Denmark)

    Bowden, Joseph James; Hansen, Rikke Reisner; Olsen, Kent;

    2015-01-01

    habitats. Such differences between habitats may influence the effects of climate changes on animals and this could be especially true in low-mobility species. Suitable model systems to test this idea, however, are rare. We examined how proxies of reproductive success (body size, juvenile/female ratios......Abstract Terrestrial ecosystems are heterogeneous habitat mosaics of varying vegetation types that are differentially affected by climate change. Arctic plant communities, for example, are changing faster in moist habitats than in dry habitats and abiotic changes like snowmelt vary locally among......) and sex ratios have changed in low-mobility crab spiders collected systematically over a 17-year period (1996–2012) from two distinct habitats (mesic and arid dwarf shrub heath) at Zackenberg in northeast Greenland. We identified all adults in the collection to confirm that they represented just one...

  6. Human-induced Arctic moistening.

    Science.gov (United States)

    Min, Seung-Ki; Zhang, Xuebin; Zwiers, Francis

    2008-04-25

    The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming in the Arctic, and fluctuations of regional fresh water inflow to the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence. By comparing observations to simulations from 22 coupled climate models, we find influence from anthropogenic greenhouse gases and sulfate aerosols in the space-time pattern of precipitation change over high-latitude land areas north of 55 degrees N during the second half of the 20th century. The human-induced Arctic moistening is consistent with observed increases in Arctic river discharge and freshening of Arctic water masses. This result provides new evidence that human activity has contributed to Arctic hydrological change.

  7. Investigating the effects of arctic dietary intake on lung health

    DEFF Research Database (Denmark)

    Baines, K J; Backer, V; Gibson, P G;

    2015-01-01

    BACKGROUND/OBJECTIVE: Preservation of lung health requires understanding the modifiable risk factors of airflow limitation. This study investigates the association between diet and lung function in a population of Greenland Inuit residing in the Arctic (Greenland) or Western Europe (Denmark...... assessed using multiple linear regression models. RESULTS: The dietary composition differed significantly in the two regions, with higher whale, seal and wild meat intake and lower fruit and vegetable intake in the Arctic regions compared with Denmark. Consumption of vegetables (P=0.004) and whale and....../or seal (Pfruit intake was included in the statistical models; however, it did not reach statistical significance (FEV1: P=0.053; FVC: P=0.055). CONCLUSIONS: High...

  8. Turnover of recently assimilated carbon in arctic bryophytes.

    Science.gov (United States)

    Street, L E; Subke, J A; Sommerkorn, M; Heinemeyer, A; Williams, M

    2011-10-01

    Carbon (C) allocation and turnover in arctic bryophytes is largely unknown, but their response to climatic change has potentially significant impacts on arctic ecosystem C budgets. Using a combination of pulse-chase experiments and a newly developed model of C turnover in bryophytes, we show significant differences in C turnover between two contrasting arctic moss species (Polytrichum piliferum and Sphagnum fuscum). (13)C abundance in moss tissues (measured up to 1 year) and respired CO(2) (traced over 5 days) were used to parameterise the bryophyte C model with four pools representing labile and structural C in photosynthetic and stem tissue. The model was optimised using an Ensemble Kalman Filter to ensure a focus on estimating the confidence intervals (CI) on model parameters and outputs. The ratio of aboveground NPP:GPP in Polytrichum piliferum was 23% (CI 9-35%), with an average turnover time of 1.7 days (CI 1.1-2.5 days). The aboveground NPP:GPP ratio in Sphagnum fuscum was 43% (CI 19-65%) with an average turnover time of 3.1 days (CI 1.6-6.1 days). These results are the first to show differences in C partitioning between arctic bryophyte species in situ and highlight the importance of modelling C dynamics of this group separately from vascular plants for a realistic representation of vegetation in arctic C models.

  9. Estimating Summer Ocean Heating in the Arctic Ice Pack Using High-Resolution Satellite Imagery

    Science.gov (United States)

    2014-09-01

    requirement (Lee et al. 2012). As Suh (2011) discussed, Arctic sea ice is affected from both surface melting due to atmospheric conditions, as well as...OCEAN HEATING IN THE ARCTIC ICE PACK USING HIGH-RESOLUTION SATELLITE IMAGERY by Ander S. Heiles September 2014 Thesis Advisor: Timothy...September 2014 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE ESTIMATING SUMMER OCEAN HEATING IN THE ARCTIC ICE PACK

  10. Comprimento da estaca e tipo de substrato na propagação vegetativa de atroveran Shoot cutting length and substrate types on vegetative propagation of atroveran

    Directory of Open Access Journals (Sweden)

    Larissa Corrêa do Bomfim Costa

    2007-08-01

    Full Text Available A propagação vegetativa de espécies medicinais vem despertando interesse das pesquisas agronômicas, uma vez que se constitui no ponto de partida e em ferramenta básica para qualquer cultivo em escala comercial. Este trabalho objetivou determinar o comprimento de estaca e o tipo de substrato mais adequados para a propagação vegetativa de atroveran. Em condições de casa de vegetação sob nebulização intermitente, foram testados dois comprimentos de estacas (10 e 20cm e três substratos (areia lavada, casca de arroz carbonizada e substrato comercial Plantmax®, em delineamento experimental em blocos casualizados, com quatro repetições e cinco estacas por parcela. Aos trinta e cinco dias, foram avaliados a porcentagem de enraizamento, o comprimento da maior raiz (cm e a biomassa seca das folhas e das raízes (mg. Os resultados indicaram que a propagação vegetativa de atroveran por meio de estaquia é viável, uma vez que o seu enraizamento médio ficou acima de 70%. As mudas de atroveran obtidas de estacas com 20cm apresentaram maior biomassa seca das folhas e das raízes, apesar de o comprimento da estaca não ter afetado a porcentagem de enraizamento e o comprimento da raiz. Os tipos de substrato não proporcionaram efeito sobre o desenvolvimento das estacas de atroveran. Recomenda-se a produção de mudas de atroveran com estacas de 20cm de comprimento, utilizando-se qualquer um dos três substratos testados.The vegetative propagation of medicinal species is in increasing agronomic interest because it is the starting point and a basic tool for any cultivation in commercial scale. The objective of this work was to determine the best shoot cutting length and the best substrate for vegetative propagation of Ocimum selloi. Cuttings were placed in greenhouse conditions under intermittent mist. Two cutting sizes (10 and 20cm and three substrate types (washed sand, carbonized rice hulls and commercial substrate Plantmax® were tested

  11. VEGETATION MAPPING IN WETLANDS

    Directory of Open Access Journals (Sweden)

    F. PEDROTTI

    2004-01-01

    Full Text Available The current work examines the main aspects of wetland vegetation mapping, which can be summarized as analysis of the ecological-vegetational (ecotone gradients; vegetation complexes; relationships between vegetation distribution and geomorphology; vegetation of the hydrographic basin lo which the wetland in question belongs; vegetation monitoring with help of four vegetation maps: phytosociological map of the real and potential vegetation, map of vegetation dynamical tendencies, map of vegetation series.

  12. The relationship between vegetables and fruits intake and glycosylated hemoglobin values, lipids profiles and nitrogen status in type II inactive diabetic patients

    Directory of Open Access Journals (Sweden)

    Marjan Tabesh

    2013-01-01

    Conclusions : Intake of vegetables and fruits may reduce the glycosylated hemoglobin, therefore choosing the appropriate diet with high fruits and vegetables may help to develop antioxidant defense and reduce the HbA1C in diabetic patients but it did not have any impact on lipids profiles, BUN/creatinine and urine protein 24 h.

  13. Past and future scenarios of the effect of carbon dioxide on plant growth and transpiration for three vegetation types of southwestern France

    Directory of Open Access Journals (Sweden)

    J.-C. Calvet

    2007-04-01

    Full Text Available The sensitivity of an operational CO2-responsive land surface model (the ISBA-A-gs model of Météo-France to the atmospheric CO2 concentration, [CO2], is investigated for 3 vegetation types (winter wheat, irrigated corn, coniferous forest. Past (1960 and future (2050 scenarios of [CO2] corresponding to 320 ppm and 550 ppm, respectively, are explored. The sensitivity study is performed for 4 annual cycles presenting contrasting conditions of precipitation regime and air temperature, based on continuous measurements performed on the SMOSREX site near Toulouse, in southwestern France. A significant CO2-driven reduction of canopy conductance is simulated for the irrigated corn and the coniferous forest. The reduction is particularly large for corn, from 2000 to 2050 (–18%, and triggers a drop in optimum irrigation (–30 mm y−1. In the case of wheat, the response is more complex, with an equal occurrence of enhanced or reduced canopy conductance.

  14. Simple and robust methods for remote sensing of canopy chlorophyll content: a comparative analysis of hyperspectral data for different types of vegetation.

    Science.gov (United States)

    Inoue, Yoshio; Guérif, Martine; Baret, Frédéric; Skidmore, Andrew; Gitelson, Anatoly; Schlerf, Martin; Darvishzadeh, Roshanak; Olioso, Albert

    2016-12-01

    Canopy chlorophyll content (CCC) is an essential ecophysiological variable for photosynthetic functioning. Remote sensing of CCC is vital for a wide range of ecological and agricultural applications. The objectives of this study were to explore simple and robust algorithms for spectral assessment of CCC. Hyperspectral datasets for six vegetation types (rice, wheat, corn, soybean, sugar beet and natural grass) acquired in four locations (Japan, France, Italy and USA) were analysed. To explore the best predictive model, spectral index approaches using the entire wavebands and multivariable regression approaches were employed. The comprehensive analysis elucidated the accuracy, linearity, sensitivity and applicability of various spectral models. Multivariable regression models using many wavebands proved inferior in applicability to different datasets. A simple model using the ratio spectral index (RSI; R815, R704) with the reflectance at 815 and 704 nm showed the highest accuracy and applicability. Simulation analysis using a physically based reflectance model suggested the biophysical soundness of the results. The model would work as a robust algorithm for canopy-chlorophyll-metre and/or remote sensing of CCC in ecosystem and regional scales. The predictive-ability maps using hyperspectral data allow not only evaluation of the relative significance of wavebands in various sensors but also selection of the optimal wavelengths and effective bandwidths.

  15. Globalising the Arctic Climate:

    DEFF Research Database (Denmark)

    Corry, Olaf

    2017-01-01

    This chapter uses an object-oriented approach to explore how the Arctic is being constituted as an object of global governance within an emerging ‘global polity’, partly through geoengineering plans and political visions ('imaginaries'). It suggests that governance objects—the socially constructe...... on world politics. The emergence of the Arctic climate as a potential target of governance provides a case in point. The Arctic climate is becoming globalised, pushing it up the political agenda but drawing it away from its local and regional context.......This chapter uses an object-oriented approach to explore how the Arctic is being constituted as an object of global governance within an emerging ‘global polity’, partly through geoengineering plans and political visions ('imaginaries'). It suggests that governance objects—the socially constructed...... targets of political operations and contestations—are not simple ‘issues’ or ‘problems’ given to actors to deal with. Governance-objects emerge and are constructed through science, technology and politics, and rather than slotting neatly into existing structures, they have their own structuring effects...

  16. Communicating Arctic Change (Invited)

    Science.gov (United States)

    Serreze, M.

    2009-12-01

    Nowhere on the planet are emerging signals of climate change more visible than in the Arctic. Rapid warming, a quickly shrinking summer sea ice cover, and thawing permafrost, will have impacts that extend beyond the Arctic and may reverberate around the globe. The National Snow and Ice Data Center (NSIDC) of the University of Colorado has taken a leading role in trying to effectively communicate the science and importance of Arctic change. Our popular “Sea Ice News and Analysis” web site tracks the Arctic’s shrinking ice cover and provides scientific analysis with language that is accurate yet accessible to a wide audience. Our Education Center provides accessible information on all components of the Earth’s cryosphere, the changes being seen, and how scientists conduct research. A challenge faced by NSIDC is countering the increasing level of confusion and misinformation regarding Arctic and global change, a complex problem that reflects the low level of scientific literacy by much of the public, the difficulties many scientists face in communicating their findings in accurate but understandable terms, and efforts by some groups to deliberately misrepresent and distort climate change science. This talk will outline through examples ways in which NSIDC has been successful in science communication and education, as well as lessons learned from failures.

  17. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk

    2017-01-01

    Since the Industrial Revolution, the anthropogenic emission of greenhouse gases has been increasing, leading to a rise in the global temperature. Particularly in the Arctic, climate change is having serious impact where the average temperature has increased almost twice as much as the global during...

  18. The Arctic Circle

    Science.gov (United States)

    McDonald, Siobhan

    2016-04-01

    My name is Siobhan McDonald. I am a visual artist living and working in Dublin. My studio is based in The School of Science at University College Dublin where I was Artist in Residence 2013-2015. A fascination with time and the changeable nature of landmass has led to ongoing conversations with scientists and research institutions across the interweaving disciplines of botany, biology and geology. I am developing a body of work following a recent research trip to the North Pole where I studied the disappearing landscape of the Arctic. Prompted by my experience of the Arctic shelf receding, this new work addresses issues of the instability of the earth's materiality. The work is grounded in an investigation of material processes, exploring the dynamic forces that transform matter and energy. This project combines art and science in a fascinating exploration of one of the Earth's last relatively untouched wilderness areas - the High Arctic to bring audiences on journeys to both real and artistically re-imagined Arctic spaces. CRYSTALLINE'S pivotal process is collaboration: with The European Space Agency; curator Helen Carey; palaeontologist Prof. Jenny McElwain, UCD; and with composer Irene Buckley. CRYSTALLINE explores our desire to make corporeal contact with geological phenomena in Polar Regions. From January 2016, in my collaboration with Jenny McElwain, I will focus on the study of plants and atmospheres from the Arctic regions as far back as 400 million years ago, to explore the essential 'nature' that, invisible to the eye, acts as imaginary portholes into other times. This work will be informed by my arctic tracings of sounds and images recorded in the glaciers of this disappearing frozen landscape. In doing so, the urgencies around the tipping of natural balances in this fragile region will be revealed. The final work will emerge from my forthcoming residency at the ESA in spring 2016. Here I will conduct a series of workshops in ESA Madrid to work with

  19. Challenges in Modeling Disturbance Regimes and Their Impacts in Arctic and Boreal Ecosystems (Invited)

    Science.gov (United States)

    McGuire, A. D.; Rupp, T. S.; Kurz, W.

    2013-12-01

    Disturbances in arctic and boreal terrestrial ecosystems influence services provided by these ecosystems to society. In particular, changes in disturbance regimes in northern latitudes have uncertain consequences for the climate system. A major challenge for the scientific community is to develop the capability to predict how the frequency, severity and resultant impacts of disturbance regimes will change in response to future changes in climate projected for northern high latitudes. Here we compare what is known about drivers and impacts of wildfire, phytophagous insect pests, and thermokarst disturbance to illustrate the complexities in predicting future changes in disturbance regimes and their impacts in arctic and boreal regions. Much of the research on predicting fire has relied on the use of drivers related to fire weather. However, changes in vegetation, such as increases in broadleaf species, associated with intensified fire regimes have the potential to influence future fire regimes through negative feedbacks associated with reduced flammability. Phytophagous insect outbreaks have affected substantial portions of the boreal region in the past, but frequently the range of the tree host is larger than the range of the insect. There is evidence that a number of insect species are expanding their range in response to climate change. Major challenges to predicting outbreaks of phytophagous insects include modeling the effects of climate change on insect growth and maturation, winter mortality, plant host health, the synchrony of insect life stages and plant host phenology, and changes in the ranges of insect pests. Moreover, Earth System Models often simplify the representation of vegetation characteristics, e.g. the use of plant functional types, providing insufficient detail to link to insect population models. Thermokarst disturbance occurs when the thawing of ice-rich permafrost results in substantial ground subsidence. In the boreal forest, thermokarst can

  20. Some discussions on Arctic vortex

    Institute of Scientific and Technical Information of China (English)

    Li Hai; Sun Lantao; Wu Huiding; Li Xiang

    2006-01-01

    The Arctic vortex is a persistent large-scale cyclonic circulation in the middle and upper troposphere and the stratosphere. Its activity and variation control the semi-permanent active centers of Pan-Arctic and the short-time cyclone activity in the subarctic areas. Its strength variation, which directly relates to the atmosphere, ocean, sea ice and ecosystem of the Arctic, can affect the lower atmospheric circulation, the weather of subarctic area and even the weather of middle latitude areas. The 2003 Chinese Second Arctic Research Expedition experienced the transition of the stratosphereic circulation from a warm anticyclone to a cold cyclone during the ending period of Arctic summertime, a typical establishing process of the polar vortex circulation. The impact of the polar vortex variation on the low-level circulation has been investigated by some scientists through studying the coupling mechanisms of the stratosphere and troposphere. The impact of the Stratospheric Sudden Warming (SFW) events on the polar vortex variation was drawing people's great attention in the fifties of the last century. The Arctic Oscillation (AO) , relating to the variation of the Arctic vortex, has been used to study the impact of the Arctic vortex on climate change. The recent Arctic vortex studies are simply reviewed and some discussions on the Arctic vertex are given in the paper. Some different views and questions are also discussed.

  1. Arctic ice islands

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

    1988-01-01

    The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

  2. Islands of the Arctic

    Science.gov (United States)

    Dowdeswell, Julian; Hambrey, Michael

    2002-11-01

    The Arctic islands are characterized by beautiful mountains and glaciers, in which the wildlife lives in delicate balance with its environment. It is a fragile region with a long history of exploration and exploitation that is now experiencing rapid environmental change. All of these themes are explored in Islands of the Arctic, a richly illustrated volume with superb photographs from the Canadian Arctic archipelago, Greenland, Svalbard and the Russian Arctic. It begins with the various processes shaping the landscape: glaciers, rivers and coastal processes, the role of ice in the oceans and the weather and climate. Julian Dowdeswell and Michael Hambrey describe the flora and fauna in addition to the human influences on the environment, from the sustainable approach of the Inuit, to the devastating damage inflicted by hunters and issues arising from the presence of military security installations. Finally, they consider the future prospects of the Arctic islands Julian Dowdeswell is Director of the Scott Polar Research Institute and Professor of Physical Geography at 0he University of Cambridge. He received the Polar Medal from Queen Elizabeth for his contributions to the study of glacier geophysics and the Gill Memorial Award from the Royal Geographical Society. He is chair of the Publications Committee of the International Glaciological Society and head of the Glaciers and Ice Sheets Division of the International Commission for Snow and Ice. Michael Hambrey is Director of the Centre for Glaciology at the University of Wales, Aberystwyth. A past recipient of the Polar Medal, he was also given the Earth Science Editors' Outstanding Publication Award for Glaciers (Cambridge University Press). Hambrey is also the author of Glacial Environments (British Columbia, 1994).

  3. General Vegetation

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This file contains vector digital data for vegetation groupings in New Mexico at a 1:1,000,000 scale. The source software was ARC/INFO 5.0.1 and the conversion...

  4. Modeling the summertime Arctic cloudy boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J.A.; Pinto, J.O. [Univ. of Colorado, Boulder, CO (United States); McInnes, K.L. [CSIRO Division of Atmospheric Research, Mordialloc (Australia)

    1996-04-01

    Global climate models have particular difficulty in simulating the low-level clouds during the Arctic summer. Model problems are exacerbated in the polar regions by the complicated vertical structure of the Arctic boundary layer. The presence of multiple cloud layers, a humidity inversion above cloud top, and vertical fluxes in the cloud that are decoupled from the surface fluxes, identified in Curry et al. (1988), suggest that models containing sophisticated physical parameterizations would be required to accurately model this region. Accurate modeling of the vertical structure of multiple cloud layers in climate models is important for determination of the surface radiative fluxes. This study focuses on the problem of modeling the layered structure of the Arctic summertime boundary-layer clouds and in particular, the representation of the more complex boundary layer type consisting of a stable foggy surface layer surmounted by a cloud-topped mixed layer. A hierarchical modeling/diagnosis approach is used. A case study from the summertime Arctic Stratus Experiment is examined. A high-resolution, one-dimensional model of turbulence and radiation is tested against the observations and is then used in sensitivity studies to infer the optimal conditions for maintaining two separate layers in the Arctic summertime boundary layer. A three-dimensional mesoscale atmospheric model is then used to simulate the interaction of this cloud deck with the large-scale atmospheric dynamics. An assessment of the improvements needed to the parameterizations of the boundary layer, cloud microphysics, and radiation in the 3-D model is made.

  5. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international...... network of scientists, conservation organizations, government agencies, Permanent Participants Arctic community experts and leaders. Using an ecosystem-based monitoring approach which includes species, ecological functions, ecosystems, their interactions, and potential drivers, the CBMP focuses...... on developing and implementing long-term plans for monitoring the integrity of Arctic biomes: terrestrial, marine, freshwater, and coastal (under development) environments. The CBMP Terrestrial Expert Monitoring Group (CBMP-TEMG) has developed the Arctic Terrestrial Biodiversity Monitoring Plan (CBMP...

  6. The soil microbial community composition and soil microbial carbon uptake are more affected by soil type than by different vegetation types (C3 and C4 plants) and seasonal changes

    Science.gov (United States)

    Griselle Mellado Vazquez, Perla; Lange, Markus; Gleixner, Gerd

    2016-04-01

    This study investigates the influence of different vegetation types (C3 and C4 plants), soil type and seasonal changes on the soil microbial biomass, soil microbial community composition and soil microbial carbon (C) uptake. We collected soil samples in winter (non-growing season) and summer (growing season) in 2012 from an experimental site cropping C3 and C4 plants for 6 years on two different soil types (sandy and clayey). The amount of phospholipid fatty acids (PLFAs) and their compound-specific δ13C values were used to determined microbial biomass and the flow of C from plants to soil microorganisms, respectively. Higher microbial biomass was found in the growing season. The microbial community composition was mainly explained by soil type. Higher amounts of SOC were driving the predominance of G+ bacteria, actinobacteria and cyclic G- bacteria in sandy soils, whereas root biomass was significantly related to the increased proportions of G- bacteria in clayey soils. Plant-derived C in G- bacteria increased significantly in clayey soils in the growing season. This increase was positively and significantly driven by root biomass. Moreover, changes in plant-derived C among microbial groups pointed to specific capabilities of different microbial groups to decompose distinct sources of C. We concluded that soil texture and favorable growth conditions driven by rhizosphere interactions are the most important factors controlling the soil microbial community. Our results demonstrate that a change of C3 plants vs. C4 plants has only a minor effect on the soil microbial community. Thus, such experiments are well suited to investigate soil organic matter dynamics as they allow to trace the C flow from plants into the soil microbial community without changing the community abundance and composition.

  7. Japan’s arctic policy

    Directory of Open Access Journals (Sweden)

    Dmitry V. Streltsov

    2017-01-01

    Full Text Available Abstract: The article is devoted to the public policy of modern Japan in the Arctic. The Japanese government has put forward clear and well-specifi ed targets of the intensifi cation of Japan’s efforts in the economic development of the Arctic region. Among the priorities of the Arctic policy one should mention such areas as the development of maritime transportation, development of hydrocarbon deposits of the Arctic shelf, sea fi shing, as well as the preservation and increase of the sea bioresources.

  8. Arctic River organic matter transport

    Science.gov (United States)

    Raymond, Peter; Gustafsson, Orjan; Vonk, Jorien; Spencer, Robert; McClelland, Jim

    2016-04-01

    Arctic Rivers have unique hydrology and biogeochemistry. They also have a large impact on the Arctic Ocean due to the large amount of riverine inflow and small ocean volume. With respect to organic matter, their influence is magnified by the large stores of soil carbon and distinct soil hydrology. Here we present a recap of what is known of Arctic River organic matter transport. We will present a summary of what is known of the ages and sources of Arctic River dissolved and particulate organic matter. We will also discuss the current status of what is known about changes in riverine organic matter export due to global change.

  9. Experimentally determined temperature thresholds for Arctic plankton community metabolism

    Directory of Open Access Journals (Sweden)

    J. M. Holding

    2013-01-01

    Full Text Available Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 °C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions based on the metabolic theory of ecology assume that temperature increase will enhance metabolic rates and thus both the rate of primary production and respiration will increase. However, these predictions do not consider the specific metabolic balance of the communities. We tested, experimentally, the response of Arctic plankton communities to seawater temperature spanning from 1 °C to 10 °C. Two types of communities were tested, open-ocean Arctic communities from water collected in the Barents Sea and Atlantic influenced fjord communities from water collected in the Svalbard fjord system. Metabolic rates did indeed increase as suggested by metabolic theory, however these results suggest an experimental temperature threshold of 5 °C, beyond which the metabolism of plankton communities shifts from autotrophic to heterotrophic. This threshold is also validated by field measurements across a range of temperatures which suggested a temperature 5.4 °C beyond which Arctic plankton communities switch to heterotrophy. Barents Sea communities showed a much clearer threshold response to temperature manipulations than fjord communities.

  10. The Arctic Circle Revisited

    CERN Document Server

    Colomo, F

    2007-01-01

    The problem of limit shapes in the six-vertex model with domain wall boundary conditions is addressed by considering a specially tailored bulk correlation function, the emptiness formation probability. A closed expression of this correlation function is given, both in terms of certain determinant and multiple integral, which allows for a systematic treatment of the limit shapes of the model for full range of values of vertex weights. Specifically, we show that for vertex weights corresponding to the free-fermion line on the phase diagram, the emptiness formation probability is related to a one-matrix model with a triple logarithmic singularity, or Triple Penner model. The saddle-point analysis of this model leads to the Arctic Circle Theorem, and its generalization to the Arctic Ellipses, known previously from domino tilings.

  11. Research with Arctic peoples

    DEFF Research Database (Denmark)

    Smith, H Sally; Bjerregaard, Peter; Chan, Hing Man

    2006-01-01

    of environmental and health issues that are unique to the Arctic regions, and research exploring these issues offers significant opportunities, as well as challenges. On July 28-29, 2004, the National Heart, Lung, and Blood Institute and the Canadian Institutes of Health Research co-sponsored a working group...... entitled "Research with Arctic Peoples: Unique Research Opportunities in Heart, Lung, Blood and Sleep Disorders". The meeting was international in scope with investigators from Greenland, Iceland and Russia, as well as Canada and the United States. Multiple health agencies from Canada and the United States...... sent representatives. Also attending were representatives from the International Union for Circumpolar Health (IUCH) and the National Indian Health Board. The working group developed a set of ten recommendations related to research opportunities in heart, lung, blood and sleep disorders; obstacles...

  12. Spatial Vegetation Data for Sagamore Hill National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This shapefile is the final vegetation map of Sagamore Hill National Historic Site that provides local names for vegetation types, as well as crosswalks to the...

  13. Spatial Vegetation Data for Allegheny Portage Railroad National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Vegetation map of Allegheny Portage Railroad National Historic Site provides local park-specific names for vegetation types, as well as crosswalks to the National...

  14. Green Arctic Patrol Vessel

    Science.gov (United States)

    2011-08-01

    Search Radar (2D) Non-rotating IFF system Electro- Optical security system Naval Surface Warfare Center Carderock Division Green Arctic Patrol...Speed Endurance Modular Systems and Capabilities UUV Bluefin 21 4.93 0.53 750 kg 4,500 m 25 hours Side scan sonar, multibeam ...sensors, 256 Mb flash card USV ASV 6300 6.30 Beam: 0.65 Height: 3.50 2.0 tonnes 8 kt 96 hours @ 4 kt Multibeam , sidescan sonars, CTD

  15. Disparities in Arctic Health

    Centers for Disease Control (CDC) Podcasts

    2008-02-04

    Life at the top of the globe is drastically different. Harsh climate devoid of sunlight part of the year, pockets of extreme poverty, and lack of physical infrastructure interfere with healthcare and public health services. Learn about the challenges of people in the Arctic and how research and the International Polar Year address them.  Created: 2/4/2008 by Emerging Infectious Diseases.   Date Released: 2/20/2008.

  16. Summer Arctic sea fog

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Synchronous or quasi-synchronous sea-land-air observations were conducted using advanced sea ice, atmospheric and marine instruments during China' s First Arctic Expedition. Based on the Precious data from the expedition, it was found that in the Arctic Ocean, most part of which is covered with ice or is mixed with ice, various kinds of sea fog formed such as advection fog, radiation fog and vapor fog. Each kind has its own characteristic and mechanics of creation. In the southern part of the Arctic Ocean, due to the sufficient warm and wet flow there, it is favorable for advection fog to form,which is dense and lasts a long time. On ice cap or vast floating ice, due to the strong radiation cooling effect, stable radiating fog is likely to form. In floating ice area there forms vapor fog with the appearance of masses of vapor from a boiling pot, which is different from short-lasting land fog. The study indicates that the reason why there are many kinds of sea fog form in the Arctic Ocean is because of the complicated cushion and the consequent sea-air interaction caused by the sea ice distribution and its unique physical characteristics. Sea fog is the atmospheric phenomenon of sea-air heat exchange. Especially, due to the high albedo of ice and snow surface, it is diffcult to absorb great amount of solar radiation during the polar days. Besides, ice is a poor conductor of heat; it blocks the sea-air heat exchange.The sea-air exchange is active in floating ice area where the ice is broken. The sea sends heat to the atmosphere in form of latent heat; vapor fog is a way of sea-air heat exchange influencing the climate and an indicator of the extent of the exchange. The study also indicates that the sea also transports heat to the atmosphere in form of sensible heat when vapor fog occurs.

  17. Green Arctic Patrol Vessel

    Science.gov (United States)

    2010-10-01

    design with a full load displacement of 6,480 long tons. The vessel was outfitted with a towed sonary array, surface and air radar, and a small...and system complexity. 15. SUBJECT TERMS Arctic patrol, green technology, environment, polution , ship design, CISD, fuel cell 16. SECURITY...was outfitted with a towed sonary array, surface and air radar, and a small interdiction and rescue craft. In anticipation of more stringent

  18. Russia in the Arctic

    Science.gov (United States)

    2011-07-01

    international energy mar- kets determines, in many ways, its geopolitical influ- ence.”63 As the late Roman Kupchinksy pointed out, the view that...available from www.scrf. gov.ru/documents/99.html. 63. Roman Kupchinsky, “Energy and the Russian National Security Strategy,” Jamestown Foundation... Jakobson , Linda, “China prepares for an ice-free Arctic,” SIPRI Insights on Peace and Security, No. 2010/2, March 2010, Stockholm International Peace

  19. International Arctic Research Programs

    Science.gov (United States)

    1989-07-01

    our re- 27 Demand for multi-disciplinary of the boreal forest zone -, should discuss the feazibility of establishing a mechanism Scientific Cooperation...interactions, very low frequency waves, auroras , and precipitation of energetic particles from the mag- netosphere. Ocean Sciences research has...vestigating the aurora phenomenon, which can have a severe impact on communications, and the dynamics of the upper atmosphere, including the arctic

  20. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    Science.gov (United States)

    Vavrus, S. J.

    2012-12-01

    Although impending Arctic climate change is widely recognized, a wild card in its expression is how extreme weather events in this region will respond to greenhouse warming. Intense polar cyclones represent one type of high-latitude phenomena falling into this category, including very deep synoptic-scale cyclones and mesoscale polar lows. These systems inflict damage through high winds, heavy precipitation, and wave action along coastlines, and their impact is expected to expand in the future, when reduced sea ice cover allows enhanced wave energy. The loss of a buffering ice pack could greatly increase the rate of coastal erosion, which has already been increasing in the Arctic. These and related threats may amplify if extreme Arctic cyclones become more frequent and/or intense in a warming climate with much more open water to fuel them. This possibility has merit on the basis of GCM experiments, which project that greenhouse forcing causes lower mean sea level pressure (SLP) in the Arctic and a strengthening of the deepest storms over boreal high latitudes. In this study, the latest Coupled Model Intercomparison Project (CMIP5) climate model output is used to investigate the following questions: (1) What are the spatial and seasonal characteristics of extreme Arctic cyclones? (2) How well do GCMs simulate these phenomena? (3) Are Arctic cyclones already showing the expected response to greenhouse warming in climate models? To address these questions, a retrospective analysis is conducted of the transient 20th century simulations among the CMIP5 GCMs (spanning years 1850-2005). The results demonstrate that GCMs are able to reasonably represent extreme Arctic cyclones and that the simulated characteristics do not depend significantly on model resolution. Consistent with observational evidence, climate models generate these storms primarily during winter and within the climatological Aleutian and Icelandic Low regions. Occasionally the cyclones remain very intense

  1. Tracing the origin of Arctic driftwood

    Science.gov (United States)

    Hellmann, Lena; Tegel, Willy; Eggertsson, Ã.`Lafur; Schweingruber, Fritz Hans; Blanchette, Robert; Kirdyanov, Alexander; GäRtner, Holger; Büntgen, Ulf

    2013-03-01

    Arctic environments, where surface temperatures increase and sea ice cover and permafrost depth decrease, are very sensitive to even slight climatic variations. Placing recent environmental change of the high-northern latitudes in a long-term context is, however, complicated by too short meteorological observations and too few proxy records. Driftwood may represent a unique cross-disciplinary archive at the interface of marine and terrestrial processes. Here, we introduce 1445 driftwood remains from coastal East Greenland and Svalbard. Macroscopy and microscopy were applied for wood anatomical classification; a multi-species subset was used for detecting fungi; and information on boreal vegetation patterns, circumpolar river systems, and ocean current dynamics was reviewed and evaluated. Four conifer (Pinus, Larix, Picea, and Abies) and three deciduous (Populus, Salix, and Betula) genera were differentiated. Species-specific identification also separated Pinus sylvestris and Pinus sibirica, which account for ~40% of all driftwood and predominantly originate from western and central Siberia. Larch and spruce from Siberia or North America represents ~26% and ~18% of all materials, respectively. Fungal colonization caused different levels of driftwood staining and/or decay. Our results demonstrate the importance of combining wood anatomical knowledge with insight on boreal forest composition for successfully tracing the origin of Arctic driftwood. To ultimately reconstruct spatiotemporal variations in ocean currents, and to better quantify postglacial uplift rates, we recommend consideration of dendrochronologically dated material from many more circumpolar sites.

  2. Mining in the European Arctic

    NARCIS (Netherlands)

    van Dam, Kim; Scheepstra, Annette; Gille, Johan; Stępień, Adam; Koivurova, Timo

    2014-01-01

    The European Arctic is currently experiencing an upsurge in mining activities, but future developments will be highly sensitive to mineral price fluctuations. The EU is a major consumer and importer of Arctic raw materials. As the EU is concerned about the security of supply, it encourages domestic

  3. Arctic interests and policy of France

    OpenAIRE

    Yuri I. Rubinsky

    2016-01-01

    The author considers scientific, economic and political activities of France for the development and exploration of the Arctic, providing security there. Along with some other non-Arctic countries, France is not ready to accept such a situation when eight members of the Arctic Council solve Arctic problems on behalf of all mankind.

  4. AMAP Assessment 2013: Arctic Ocean acidification

    Science.gov (United States)

    2013-01-01

    This assessment report presents the results of the 2013 AMAP Assessment of Arctic Ocean Acidification (AOA). This is the first such assessment dealing with AOA from an Arctic-wide perspective, and complements several assessments that AMAP has delivered over the past ten years concerning the effects of climate change on Arctic ecosystems and people. The Arctic Monitoring and Assessment Programme (AMAP) is a group working under the Arctic Council. The Arctic Council Ministers have requested AMAP to: - produce integrated assessment reports on the status and trends of the conditions of the Arctic ecosystems;

  5. Long-range transport of air pollution into the Arctic

    Science.gov (United States)

    Stohl, A.; Berg, T.; Breivik, K.; Burkhart, J. F.; Eckhardt, S.; Fjæraa, A.; Forster, C.; Herber, A.; Lunder, C.; McMillan, W. W.; None, N.; Manø, S.; Oltmans, S.; Shiobara, M.; Stebel, K.; Hirdman, D.; Stroem, J.; Tørseth, K.; Treffeisen, R.; Virkkunen, K.; Yttri, K. E.; Andrews, E.; Kowal, D.; Mefford, T.; Ogren, J. A.; Sharma, S.; Spichtinger, N.; Stone, R.; Hoch, S.; Wehrli, C.

    2007-12-01

    This paper presents an overview of air pollution transport into the Arctic. The major transport processes will be highlighted, as well as their seasonal, interannual, and spatial variability. The source regions of Arctic air pollution will be discussed, with a focus on black carbon (BC) sources, as BC can produce significant radiative forcing in the Arctic. It is found that Europe is the main source region for BC in winter, whereas boreal forest fires are the strongest source in summer, especially in years of strong burning. Two case studies of recent extreme Arctic air pollution events will be presented. In summer 2004, boreal forest fires in Alaska and Canada caused pan-Arctic enhancements of black carbon. The BC concentrations measured at Barrow (Alaska), Alert (Canada), Summit (Greenland) and Zeppelin (Spitsbergen) were all episodically elevated, as a result of the long-range transport of the biomass burning emissions. Aerosol optical depth was also episodically elevated at these stations, with an almost continuous elevation over more than a month at Summit. During the second episode in spring 2006, new records were set for all measured air pollutant species at the Zeppelin station (Spitsbergen) as well as for ozone in Iceland. At Zeppelin, BC, AOD, aerosol mass, ozone, carbon monoxide and other compounds all reached new record levels, compared to the long-term monitoring record. The episode was caused by transport of polluted air masses from Eastern Europe deep into the Arctic, a consequence of the unusual warmth in the European Arctic during the episode. While fossil fuel combustion sources certainly contributed to this episode, smoke from agricultural fires in Eastern Europe was the dominant pollution component. We also suggest a new revolatilization mechanism for persistent organic pollutants (POPs) stored in soils and vegetation by fires, as POPs were strongly elevated during both episodes. All this suggests a considerable influence of biomass burning on

  6. The Sub-Arctic Carbon Cycle: Assimilating Multi-Scale Chamber, Tower and Aircraft Flux Observations into Ecological Models

    Science.gov (United States)

    Hill, T. C.; Stoy, P. C.; Baxter, R.; Clement, R.; Disney, M.; Evans, J.; Fletcher, B.; Gornall, J.; Harding, R.; Hartley, I. P.; Ineson, P.; Moncrieff, J.; Phoenix, G.; Sloan, V.; Poyatos, R.; Prieto-Blanco, A.; Subke, J.; Street, L.; Wade, T. J.; Wayolle, A.; Wookey, P.; Williams, M. D.

    2009-12-01

    The Arctic has already warmed significantly, and warming of 4-7 °C is expected over the next century. However, linkages between climate, the carbon cycle, the energy balance, and hydrology mean that the response of arctic ecosystems to these changes remains poorly understood. The release by warming of considerable but poorly quantified carbon stores from high latitude soils could accelerate the build-up of atmospheric CO2. The Arctic Biosphere Atmosphere Coupling at Multiple Scales (ABACUS) project, part of International Polar Year, was designed to improve predictions of the response of the Arctic terrestrial biosphere to climate change. The project operated at two sites (Abisko, Sweden and Kevo, Finland) over multiple years, utilising roving flux chambers (CO2/CH4), five flux towers (CO2/CH4/H2O) and a research aircraft equipped for fluxes (CO2/H2O) to directly measure multi-scale exchanges in-conjunction with other observations (both plot level and satellite). We show how these data can be combined using data assimilation approaches to address the question “what controls the temporal and spatial variability of carbon exchange by sub-Arctic ecosystems?” Eddy covariance measurements of mire methane exchanges agreed with chamber estimates, indicating that mires were strong summer sources, while birch woodland was a weak sink. However, remote sensing of mire extent was limited at resolutions > 30 m, and variations in sink/source activity suggested that upscaling CH4 exchanges (from chamber, to tower, to landscape) required higher resolution (ideally exchange recorded similar seasonal timing over a range of vegetation types. Birch woodlands had the greatest range of CO2 exchanges compared to tundra and mires. The challenge of measuring continuous fluxes across the full annual cycle, and inherent uncertainties in the methods, complicates the determination of source/sink status of the landscapes, but cold season data were successfully collected. Aircraft flux

  7. Arctic Ecosystem Integrated Survey (Arctic Eis): Marine ecosystem dynamics in the rapidly changing Pacific Arctic Gateway

    Science.gov (United States)

    Mueter, Franz J.; Weems, Jared; Farley, Edward V.; Sigler, Michael F.

    2017-01-01

    Arctic Marine Ecosystems are undergoing rapid changes associated with ice loss and surface warming resulting from human activities (IPCC, 2013). The most dramatic changes include an earlier ice retreat and a longer ice-free season, particularly on Arctic inflow shelves such as the Barents Sea in the Atlantic Arctic and the northern Bering Sea and Chukchi Sea in the Pacific Arctic, the two major gateways into the Arctic (Danielson et al., 2016; Frey et al., 2015; Serreze et al., 2007; Wood et al., 2015). The retreat of Arctic sea ice has opened access to the Arctic marine environment and its resources, particularly during summer, and among other changes has brought with it increased research activities. For the Pacific Arctic region, these activities have led to several recent compendiums examining physical, biogeochemical, and biological patterns and trends in this rapidly changing environment (Arrigo, 2015, 2016; Arrigo et al., 2014; Bluhm et al., 2010; Dunton et al., 2014; Grebmeier and Maslowski, 2014; Hopcroft and Day, 2013; Moore and Stabeno, 2015).

  8. Variation in soil enzyme activity as a function of vegetation amount, type, and spatial structure in fire-prone Mediterranean shrublands

    NARCIS (Netherlands)

    Garcia Mayor, Angeles; Goirán, Silvana B.; Vallejo, Ramón V.; Bautista, Susana

    2016-01-01

    Fire-prone Mediterranean shrublands may be seriously threatened by land degradation due to progressive opening of the vegetation cover driven by increasing drought and fire recurrence. However, information about the consequences of this opening process for critical ecosystem functions is scant. I

  9. Assembling an Arctic Ocean Boundary Monitoring Array

    OpenAIRE

    Tsubouchi, T.

    2014-01-01

    The Arctic Ocean boundary monitoring array has been maintained over many years by six research institutes located worldwide. Our approach to Arctic Ocean boundary measurements is generating significant scientific outcomes. However, it is not always easy to access Arctic data. On the basis of our last five years’ experience of assembling pan-Arctic boundary data, and considering the success of Argo, I propose that Arctic data policy should be driven by specific scientific-based requirements. O...

  10. Arctic Summer Ice Processes

    Science.gov (United States)

    Holt, Benjamin

    1999-01-01

    The primary objective of this study is to estimate the flux of heat and freshwater resulting from sea ice melt in the polar seas. The approach taken is to examine the decay of sea ice in the summer months primarily through the use of spaceborne Synthetic Aperture Radar (SAR) imagery. The improved understanding of the dynamics of the melt process can be usefully combined with ice thermodynamic and upper ocean models to form more complete models of ice melt. Models indicate that more heat is absorbed in the upper ocean when the ice cover is composed of smaller rather than larger floes and when there is more open water. Over the course of the summer, floes disintegrate by physical forcing and heating, melting into smaller and smaller sizes. By measuring the change in distribution of floes together with open water over a summer period, we can make estimates of the amount of heating by region and time. In a climatic sense, these studies are intended to improve the understanding of the Arctic heat budget which can then be eventually incorporated into improved global climate models. This work has two focus areas. The first is examining the detailed effect of storms on floe size and open water. A strong Arctic low pressure storm has been shown to loosen up the pack ice, increase the open water concentration well into the pack ice, and change the distribution of floes toward fewer and smaller floes. This suggests episodic melting and the increased importance of horizontal (lateral) melt during storms. The second focus area is related to an extensive ship-based experiment that recently took place in the Arctic called Surface Heat Budget of the Arctic (SHEBA). An icebreaker was placed purposely into the older pack ice north of Alaska in September 1997. The ship served as the base for experimenters who deployed extensive instrumentation to measure the atmosphere, ocean, and ice during a one-year period. My experiment will be to derive similar measurements (floe size, open

  11. Arctic hydrology and meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D.L.

    1990-01-01

    During 1990, we have continued our meteorological and hydrologic data collection in support of our process-oriented research. The six years of data collected to data is unique in its scope and continuity in a North Hemisphere Arctic setting. This valuable data base has allowed us to further our understanding of the interconnections and interactions between the atmosphere/hydrosphere/biosphere/lithosphere. The increased understanding of the heat and mass transfer processes has allowed us to increase our model-oriented research efforts.

  12. Spatial Heterogeneity of Vegetation in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The spatial heterogeneity and ecological characteristics of 74 vegetation types and the lack of vegetation type within the 9.6 million km2 of Chinese territory were studied using data from the China vegetation map. The analysis used 877 large quadrats 10 mm×10 mm (actual size 100 km×100 km), which covered about 8.77 million km2. Each large-quadrat was divided into four small 5 mm×5 mm quadrats (actual size 50 km×50 km). The frequency of occurrence of all vegetation types was recorded in each small quadrat.The survey using the Shiyomi method of vegetation analysis based on the beta-binomial distribution was adopted to describe the frequency of occurrence and spatial heterogeneity for each kind of vegetation. The weighted average heterogeneity of all the vegetation types in the landscape provides a measure of the landscape level heterogeneity which describes the spatial intricacy of the existing vegetation composition.The maximum spatial vegetation heterogeneity was 0.8620 in the frigid-temperate coniferous forest of Larix(V1), which dominates cold moist northeast China. The minimum spatial heterogeneity with a low occurrence was the Caragana tibetica in the gravel desert in the western Yellow River Hetao area. The minimum occurrence with a low spatial heterogeneity was the Monsoon rainforest on rock in Guangxi and Yunnan Provinces. The vegetation types on the Qing-Zang Plateau were found to be representative of Chinese vegetation because of the very high occurrence and spatial heterogeneity of these vegetation types. The weighted average of the heterogeneity was 0.677, while the vegetation diversity index was 3.29.

  13. The Polar Crust Project- BSC Diversity and Variability in the Arctic and Antarctica

    Science.gov (United States)

    Williams, Laura; Borchhardt, Nadine; Komisc-Buchmann, Karin; Becker, Burkhard; Karsten, Ulf; Büdel, Burkhard

    2015-04-01

    The Polar Crust Project is a newly funded DFG initiative that aims to provide a precise evaluation of the biodiversity of eukaryotic green microalgae and cyanobacteria in Biological Soil Crusts (BSC) isolated from the Antarctic Peninsula and Arctic Svalbard. This project will include a thorough investigation into the composition of BSC in the Polar regions, this especially is important for Svalbard due to the severe lack of any previous research on such communities in this area. During our expedition to Spitsbergen, Svalbard in August 2014 we were particularly surprised to find that the coverage of BSC is extremely high and is certainly the dominant vegetation type around Ny Ålesund. Due to this discovery the project has now been extended to include long term measurements of CO2 gas exchange in order to gain exact seasonal carbon fixation rates and therefore discovering how the BSC contributes to the ecosystems carbon balance. The research areas of Spitsbergen were centred around 2 localities: Ny-Ålesund is a research town, home to the AWIPEV station, on the Brøgger peninsula. Longyearbyen, which is the largest settlement on the island, is found in the valley Longyeardalen on the shore of Adventfjorden. Areas where BSC is the prevalent vegetation type were identified, 6 around Ny-Ålesund and 4 for Longyearbyen, and vegetation surveys were conducted. This entailed 625 single point measurements at each site and identifying the crust/or other cover type. For example, green algal lichen, cyanobacterial crust, higher plant, open soil. Samples were also taken at every location in order to study the green algal and cyanobacterial diversity. The vegetation survey will allow us to get a good overview of the BSC composition at the different sites. In January 2015 an expedition to the Antarctic Peninsular took place, here the sampling method was repeated and therefore both Polar Regions BSC composition can be described and compared. Here, we wish to introduce the Polar

  14. The ecology and biological affinity of Arctic dinoflagellates and their paleoceanographical significance in the Canadian High Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Rochon, A [ISMER-UQAR, 310 allee des Ursulines, Rimouski QC, G5L 3A1 (Canada)], E-mail: Andre_rochon@uqar.qc.ca

    2009-01-01

    Dinoflagellates are eukaryotic organisms and constitute an important group of marine primary producers. Approximately 10-15% of living dinoflagellates produce a highly resistant dormant cyst that is fossilisable, and which constitute an excellent proxy indicator of the upper water column conditions and productivity. Relatively little is known on the distribution in time and space of the dinoflagellate life cycle (i.e., vegetative and cyst stages) in the Canadian Arctic; most studies usually focusing on other groups of organisms (e.g., diatoms). Here, we present information on the ecology of dinoflagellate cysts and how they relate to their counterpart plankton stages. We discuss the importance of considering the biological affinities of dinoflagellates cysts and their relevance for paleoceanographical interpretations. We also provide insight on the actual lack of such knowledge for the Canadian Arctic cyst and plankton assemblages.

  15. The Arctic lithosphere: an overview

    Science.gov (United States)

    Drachev, S.; Pease, V.; Stephenson, R.

    2012-04-01

    The Arctic is comprised of three deepwater oceanic basins, the Norwegian-Greenland, Eurasia, and Amerasia basins, surrounded by continental masses of the Achaean to Early Proterozoic North American, Baltica and Siberian cratons and intervening Neoproterozoic and Phanerozoic fold belts. Though the tectonic history of the Arctic continental realm spans almost three billions of years, the formation of the Arctic began with the creation of Pangaea-II supercontinent at end of Permian epoch. Between 250 and 150 Ma the Proto-Arctic was represented by the Anyui Ocean, or Angayuchum Sea - a Paleo-Pacific embayment into Pangaea II. During the Mesozoic Pangaea II was destroyed and the Anyi Ocean was isolated from the Paleo-Pacific, finally leading to the separation of Arctic Alaska-Chukchi Microcontinent from the North American side of Laurasia; the collision of this microplate with the Siberian margin occurred at ca. 125 Ma in association with the opening of the Canada Basin. The final stage of the Arctic formation took place in the Cenozoic, and was related to the propagation of the divergent Atlantic lithospheric plate boundary between North America and Baltica with the separation of the Lomonosov continental sliver from the Eurasian margin and opening of the Eurasia oceanic basin between 56 and 0 Ma. The present-day Arctic, especially its shelves and oceanic basins, is one of the least studied places on the Earth. Though we know the geology of the surrounding continental masses, there are still many questions remaining about major lithospheric divides beneath the Arctic seas, such as: • Where are the plate boundaries associated with the Amerasia Basin? • How and when did the Canada Basin open? • What was the pre-drift setting of the Chukchi Borderland? • Which tectonic processes formed the East Siberian shelves? • How and when did the major ridges in the Amerasia Basin form? • Where are the Early Tertiary plate boundaries in the Arctic? • What is the

  16. Fourfold higher tundra volatile emissions due to arctic summer warming

    Science.gov (United States)

    Lindwall, Frida; Schollert, Michelle; Michelsen, Anders; Blok, Daan; Rinnan, Riikka

    2016-03-01

    Biogenic volatile organic compounds (BVOCs), which are mainly emitted by vegetation, may create either positive or negative climate forcing feedbacks. In the Subarctic, BVOC emissions are highly responsive to temperature, but the effects of climatic warming on BVOC emissions have not been assessed in more extreme arctic ecosystems. The Arctic undergoes rapid climate change, with air temperatures increasing at twice the rate of the global mean. Also, the amount of winter precipitation is projected to increase in large areas of the Arctic, and it is unknown how winter snow depth affects BVOC emissions during summer. Here we examine the responses of BVOC emissions to experimental summer warming and winter snow addition—each treatment alone and in combination—in an arctic heath during two growing seasons. We observed a 280% increase relative to ambient in BVOC emissions in response to a 4°C summer warming. Snow addition had minor effects on growing season BVOC emissions after one winter but decreased BVOC emissions after the second winter. We also examined differences between canopy and air temperatures and found that the tundra canopy surface was on average 7.7°C and maximum 21.6°C warmer than air. This large difference suggests that the tundra surface temperature is an important driver for emissions of BVOCs, which are temperature dependent. Our results demonstrate a strong response of BVOC emissions to increasing temperatures in the Arctic, suggesting that emission rates will increase with climate warming and thereby feed back to regional climate change.

  17. An Evaluation of the Romanian Fruits and Vegetables Producers Access to Different Types of Common Agricultural Policy Instruments. Is there Any Real Consistency with the Policy Objectives?

    Directory of Open Access Journals (Sweden)

    Nicu MARCU

    2015-04-01

    Full Text Available Fruits and vegetables sectors are considered to be strategic in the European Union due to their contribution to a better human health. Among others positive effects, their intake increase reduce mortality and obesity, assuring in the same time harmonised development for young children. The present study thus focused to reveal the consistency of the measure implemented in the Common Agricultural Policy to support fruits and vegetables production in Romania in liaison with the policy objectives. The country is one of the main ten important European producers of horticultural products in terms of production volumes and acreage. Results showed that over the last seven years (2007-2014, the sectorial production drawbacks have not been ameliorated very much. Both sectors are dominated by small-size farms that can produce only seasonally and mainly for short-market chains. In the same time, the greenhouses area shrink to levels that made the country extremely dependent to imports especially for tomatoes. The analysis of the pillar one payments schemes revealed that the fruits and vegetables producers could have access to only one payment that was half from European averages. Moreover, almost half of the producers had low sizes that left them outside the eligible criteria. The measures designed for the second pillar also penalized producers through the selection criteria. These results showed that for Romania there was not a real consistency between the actual policy measures and the objectives assumed by policy makers. The future measures (2014-2020 seem to correct these negative findings being better tailored to the situation of the local fruits and vegetables producers.

  18. Arctic melt ponds and energy balance in the climate system

    Science.gov (United States)

    Sudakov, Ivan

    2017-02-01

    Elements of Earth's cryosphere, such as the summer Arctic sea ice pack, are melting at precipitous rates that have far outpaced the projections of large scale climate models. Understanding key processes, such as the evolution of melt ponds that form atop Arctic sea ice and control its optical properties, is crucial to improving climate projections. These types of critical phenomena in the cryosphere are of increasing interest as the climate system warms, and are crucial for predicting its stability. In this paper, we consider how geometrical properties of melt ponds can influence ice-albedo feedback and how it can influence the equilibria in the energy balance of the planet.

  19. Analysis of WindSat Data over Arctic Sea Ice

    Science.gov (United States)

    The radiation of the 3rd and 4th Stokes components emitted by Arctic sea ice and observed by the spaceborne fully polarimetric radiometer WindSat is investigated. Two types of analysis are carried out, spatial (maps of different quadrants of azimuth look angles) and temporal (time series of daily av...

  20. Temperature thresholds for Arctic plankton community metabolism: an experimental assessment

    Directory of Open Access Journals (Sweden)

    J. M. Holding

    2011-11-01

    Full Text Available Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 °C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase rate of warming. Predictions based on the metabolic theory of ecology assume that temperature increase will enhance metabolic rates and thus both the rate of primary production and respiration will increase. However, these predictions do not consider the specific metabolic balance of the communities. We tested experimentally the response of Arctic plankton communities to seawater temperature spanning from 1 °C to 10 °C. Two types of communities were tested, open-ocean Arctic communities from water collected in the Barents Sea and Atlantic influenced fjord communities from water collected in the Svalbard fjord system. Metabolic rates did indeed increase as suggested by metabolic theory, however these results suggest a temperature threshold of 5 °C, beyond which the metabolism of plankton communities shifts from autotrophic to heterotrophic. Barents Sea communities showed a much clearer threshold response to temperature manipulations than fjord communities.

  1. Biogeophysical feedbacks enhance Arctic terrestrial carbon sink in regional Earth system dynamics

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2014-05-01

    Full Text Available Continued warming of the Arctic will likely accelerate terrestrial carbon (C cycling by increasing both uptake and release of C. There are still large uncertainties in modelling Arctic terrestrial ecosystems as a source or sink of C. Most modelling studies assessing or projecting the future fate of C exchange with the atmosphere are based an either stand-alone process-based models or coupled climate–C cycle general circulation models, in either case disregarding biogeophysical feedbacks of land surface changes to the atmosphere. To understand how biogeophysical feedbacks will impact on both climate and C budget over Arctic terrestrial ecosystems, we apply the regional Earth system model RCA-GUESS over the CORDEX-Arctic domain. The model is forced with lateral boundary conditions from an GCMs CMIP5 climate projection under the RCP 8.5 scenario. We perform two simulations with or without interactive vegetation dynamics respectively to assess the impacts of biogeophysical feedbacks. Both simulations indicate that Arctic terrestrial ecosystems will continue to sequester C with an increased uptake rate until 2060s–2070s, after which the C budget will return to a weak C sink as increased soil respiration and biomass burning outpaces increased net primary productivity. The additional C sinks arising from biogeophysical feedbacks are considerable, around 8.5 Gt C, accounting for 22% of the total C sinks, of which 83.5% are located in areas of Arctic tundra. Two opposing feedback mechanisms, mediated by albedo and evapotranspiration changes respectively, contribute to this response. Albedo feedback dominates over winter and spring season, amplifying the near-surface warming by up to 1.35 K in spring, while evapotranspiration feedback dominates over summer exerting the evaporative cooling by up to 0.81 K. Such feedbacks stimulate vegetation growth with an earlier onset of growing-season, leading to compositional changes in woody plants and vegetation

  2. Empirical and modeled synoptic cloud climatology of the Arctic Ocean

    Science.gov (United States)

    Barry, R. G.; Newell, J. P.; Schweiger, A.; Crane, R. G.

    1986-01-01

    A set of cloud cover data were developed for the Arctic during the climatically important spring/early summer transition months. Parallel with the determination of mean monthly cloud conditions, data for different synoptic pressure patterns were also composited as a means of evaluating the role of synoptic variability on Arctic cloud regimes. In order to carry out this analysis, a synoptic classification scheme was developed for the Arctic using an objective typing procedure. A second major objective was to analyze model output of pressure fields and cloud parameters from a control run of the Goddard Institue for Space Studies climate model for the same area and to intercompare the synoptic climatatology of the model with that based on the observational data.

  3. Audubon vegetation monitoring

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is the summary and the analysis of vegetative data for the Audubon Refuge from NPWRC. The data included measurements of vegetation density, vegetation...

  4. SCICEX: Submarine Arctic Science Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  5. Development of arctic wind technology

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, H.; Marjaniemi, M.; Antikainen, P. [VTT Energy, Espoo (Finland)

    1998-10-01

    The climatic conditions of Lapland set special technical requirements for wind power production. The most difficult problem regarding wind power production in arctic regions is the build-up of hard and rime ice on structures of the machine

  6. The effect of permafrost, vegetation, and lithology on Mg and Si isotope composition of the Yenisey River and its tributaries at the end of the spring flood

    Science.gov (United States)

    Mavromatis, Vasileios; Rinder, Thomas; Prokushkin, Anatoly S.; Pokrovsky, Oleg S.; Korets, Mikhail A.; Chmeleff, Jérôme; Oelkers, Eric H.

    2016-10-01

    This work focuses on the behavior of the stable Mg and Si isotope compositions of the largest Arctic river, the Yenisey River and 28 of its major and minor tributaries during the spring flood period. Samples were collected along a 1500 km latitudinal profile covering a wide range of permafrost, lithology, and vegetation. Despite significant contrasts in the main physico-geographical, climate, and lithological parameters of the watersheds, the isotope composition of both dissolved Mg and Si was found to be only weakly influenced by the degree of the permafrost coverage, type of vegetation (forest vs. tundra), and lithology (granites, basalts, carbonates or terrigenous rocks). This observation is generally consistent with the lack of chemical uptake of Mg and Si by soil mineral formation and vegetation during the early spring. The radiogenic Sr isotope composition of the Yenisey and its tributaries varied within a narrow range (0.708 ⩽ 87Sr/86Sr ⩽ 0.711) reflecting the dominance of Phanerozoic rock weathering and/or atmospheric deposition on these compositions. The Mg and Si isotopic compositions of riverine samples reflect two main processes with distinct isotopic signatures. First, isotopically heavier Mg (δ26Mg = -1.0 ± 0.2‰) and isotopically lighter Si (δ30Si = 1.0 ± 0.25‰) are added to the waters by river suspended matter dissolution and leaching from vegetation biomass/topsoil litter. Second, isotopically lighter Mg (δ26Mg = -1.5 to -1.75‰) and isotopically heavier Si (δ30Si = 1.75-2.0‰) are delivered to the Yenisey's tributaries from deep underground water feeding the rivers via taliks. This lighter Mg and heavier Si isotopic composition is interpreted to originate from Precambrian dolomite dissolution and aluminosilicate dissolution coupled with authigenic mineral precipitation, respectively, in deep underground water reservoirs. Taking account of the isotopic composition evolution over the course of the year established earlier on mono

  7. The marsh vegetation of Kleinmond Lagoon

    Directory of Open Access Journals (Sweden)

    M. O'Callaghan

    1994-12-01

    Full Text Available The vegetation of Kleinmond Lagoon suggests that this system is in transition from an estuary to a coastal lake. Two major types of vegetation were recognized, one which is subjected to soil and water conditions of marine origin and the other which is subjected to conditions of terrestrial origin. These vegetation types are discussed and compared to the vegetation of other estuarine systems. Artificial manipulations of the mouth seem to have resulted in sediment deposition and a freshening of the system. These unseasonable manipulations also threaten the continued existence of a number of species in the system.

  8. Interaction webs in arctic ecosystems

    DEFF Research Database (Denmark)

    Schmidt, Niels M.; Hardwick, Bess; Gilg, Olivier;

    2017-01-01

    How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they ...... that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems....

  9. Communicating Climate and Ecosystem Change in the Arctic

    Science.gov (United States)

    Soreide, N. N.; Overland, J. E.; Calder, J. A.; Rodionov, S.

    2005-12-01

    There is an explosion of interest in Northern Hemisphere climate, highlighting the importance of recent changes in the Arctic on mid-latitude climate and its impact on marine and terrestrial ecosystems. Traditional sea ice and tundra dominated arctic ecosystems are being reorganizing into warmer sub-arctic ecosystem types. Over the previous two years we have developed a comprehensive, near real-time arctic change detection protocol to track physical and biological changes for presentation on the web: http://www.arctic.noaa.gov/detect. The effort provides a continuous update to the Arctic Climate Impact Assessment (ACIA) Report, released in November 2004. Principles for the protocol include an accessible narrative style, scientifically credible and objective indicators, notes multiple uses for the information, acknowledges uncertainties, and balances having too many indicators-which leads to information overload-and too few-which does not capture the complexity of the system. Screening criteria include concreteness, public awareness, being understandable, availability of historical time series, and sensitivity. The site provides sufficient information for an individual to make their own assessment regarding the balance of the evidence for tracking change. The product provides an overview, recent news, links to many arctic websites, and highlights climate, global impacts, land and marine ecosystems, and human consequences. Since its inception a year ago, it has averaged about 9000 hits an day on the web, and is a major information source as determined by Google search. The future direction focuses on understanding the causes for change. In spring 2005 we also presented a near real-time ecological and climatic surveillance website for the Bering Sea: www.beringclimate.noaa.gov. The site provides up-to-date information which ties northward shifts of fish, invertebrate and marine mammal populations to physical changes in the Arctic. This site is more technical than the

  10. Arctic species resilience

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Forchhammer, Mads C.; Jeppesen, Erik

    The peak of biological activities in Arctic ecosystems is characterized by a relative short and intense period between the start of snowmelt until the onset of frost. Recent climate changes have induced larger seasonal variation in both timing of snowmelt as well as changes mean temperatures...... and precipitation. Concurrently, phenological change has been recorded in a wide range of plants and animals, with climate change seemingly being the primary driver of these changes. A major concern is whether species and biological systems embrace the plasticity in their phenological responses needed for tracking...... the predicted increase in climate variability. Whereas species may show relatively high phenological resilience to climate change per se, the resilience of systems may be more constrained by the inherent dependence through consumer-resource interactions across trophic levels. During the last 15 years...

  11. Research in remote sensing of vegetation

    Science.gov (United States)

    Schrumpf, Barry J.; Ripple, William J.; Isaacson, Dennis L.

    1988-01-01

    The research topics undertaken were primarily selected to further the understanding of fundamental relationships between electromagnetic energy measured from Earth orbiting satellites and terrestrial features, principally vegetation. Vegetation is an essential component in the soil formation process and the major factor in protecting and holding soil in place. Vegetation plays key roles in hydrological and nutrient cycles. Awareness of improvement or deterioration in the capacity of vegetation and the trends that those changes may indicate are, therefore, critical detections to make. A study of the relationships requires consideration of the various portions of the electromagnetic spectrum; characteristics of detector system; synergism that may be achieved by merging data from two or more detector systems or multiple dates of data; and vegetational characteristics. The vegetation of Oregon is sufficiently diverse as to provide ample opportunity to investigate the relationships suggested above several vegetation types.

  12. Texture and geochemistry of surface horizons of Arctic soils from a non-glaciated catchment, SW Spitsbergen

    Directory of Open Access Journals (Sweden)

    Szymański Wojciech

    2016-09-01

    Full Text Available Physical and chemical properties of Arctic soils and especially the properties of surface horizons of the soils are very important because they are responsible for the rate and character of plant colonization, development of vegetation cover, and influence the rate and depth of thawing of soils and development of active layer of permafrost during summer. The main aim of the present study is to determine and explain the spatial diversity of selected physical and chemical properties of surface horizons of Arctic soils from the non-glaciated Fuglebekken catchment located in the Hornsund area (SW Spitsbergen by means of geostatistical approach. Results indicate that soil surface horizons in the Fuglebekken catchment are characterized by highly variable physical and chemical properties due to a heterogeneous parent material (marine sediments, moraine, rock debris, tundra vegetation types, and non-uniform influence of seabirds. Soils experiencing the strongest influence of seabird guano have a lower pH than other soils. Soils developed on the lateral moraine of the Hansbreen glacier have the highest pH due to the presence of carbonates in the parent material and a lack or presence of a poorly developed and discontinuous A horizon. The soil surface horizons along the coast of the Hornsund exhibit the highest content of the sand fraction and SiO2. The surface of soils occurring at the foot of the slope of Ariekammen Ridge is characterized by the highest content of silt and clay fractions as well as Al2O3, Fe2O3, and K2O. Soils in the central part of the Fuglebekken catchment are depleted in CaO, MgO, and Na2O in comparison with soils in the other sampling sites, which indicates the highest rate of leaching in this part of the catchment.

  13. 77 FR 31677 - Request for Public Comment on Interagency Arctic Research Policy Committee (IARPC) Arctic...

    Science.gov (United States)

    2012-05-29

    ... TECHNOLOGY POLICY Request for Public Comment on Interagency Arctic Research Policy Committee (IARPC) Arctic... and Policy Act of 1984 (ARPA), Public Law 98-373, established the Interagency Arctic Research Policy Committee (IARPC) to develop national Arctic research policy five-year Federal research plans to...

  14. A pan-Arctic synthesis of CH4 and CO2 production from anoxic soil incubations

    Science.gov (United States)

    Treat, C.C.; Natali, Susan M.; Ernakovich, Jessica; Iverson, Colleen M.; Lupasco, Massimo; McGuire, Anthony; Norby, Richard J.; Roy Chowdhury, Taniya; Richter, Andreas; Šantrůčková, Hana; Schädel, C.; Schuur, Edward A.G.; Sloan, Victoria L.; Turetsky, Merritt R.; Waldrop, Mark P.

    2015-01-01

    Permafrost thaw can alter the soil environment through changes in soil moisture, frequently resulting in soil saturation, a shift to anaerobic decomposition, and changes in the plant community. These changes, along with thawing of previously frozen organic material, can alter the form and magnitude of greenhouse gas production from permafrost ecosystems. We synthesized existing methane (CH4) and carbon dioxide (CO2) production measurements from anaerobic incubations of boreal and tundra soils from the geographic permafrost region to evaluate large-scale controls of anaerobic CO2 and CH4 production and compare the relative importance of landscape-level factors (e.g., vegetation type and landscape position), soil properties (e.g., pH, depth, and soil type), and soil environmental conditions (e.g., temperature and relative water table position). We found fivefold higher maximum CH4 production per gram soil carbon from organic soils than mineral soils. Maximum CH4 production from soils in the active layer (ground that thaws and refreezes annually) was nearly four times that of permafrost per gram soil carbon, and CH4 production per gram soil carbon was two times greater from sites without permafrost than sites with permafrost. Maximum CH4 and median anaerobic CO2 production decreased with depth, while CO2:CH4 production increased with depth. Maximum CH4 production was highest in soils with herbaceous vegetation and soils that were either consistently or periodically inundated. This synthesis identifies the need to consider biome, landscape position, and vascular/moss vegetation types when modeling CH4 production in permafrost ecosystems and suggests the need for longer-term anaerobic incubations to fully capture CH4 dynamics. Our results demonstrate that as climate warms in arctic and boreal regions, rates of anaerobic CO2 and CH4 production will increase, not only as a result of increased temperature, but also from shifts in vegetation and increased

  15. The Arctic policy of China and Japan

    DEFF Research Database (Denmark)

    Tonami, Aki

    2014-01-01

    At the May 2013 Arctic Council Ministerial Meeting, five Asian states, namely China, Japan, India, Singapore and South Korea, were accepted to become new Permanent Observers at the Arctic Council. Nonetheless, little attention has been paid to the Asian states and their interest in the Arctic. Most...... discussions have focused on China and the assessment of China’s interest in the Arctic is divided. This paper attempts to fill this gap by presenting and comparing the various components of the Arctic policies of China and Japan. Referring to Putnam’s model of the “two-level game” and Young’s categorization...... of Arctic stakeholders’ interests, data from policy documents and interviews with relevant stakeholders were analysed. This analysis shows the Chinese and Japanese governments are in the gradual process of consolidating their Arctic policies, but both China and Japan see the Arctic less as a strategically...

  16. Time varying arctic climate change amplification

    Energy Technology Data Exchange (ETDEWEB)

    Chylek, Petr [Los Alamos National Laboratory; Dubey, Manvendra K [Los Alamos National Laboratory; Lesins, Glen [DALLHOUSIE U; Wang, Muyin [NOAA/JISAO

    2009-01-01

    During the past 130 years the global mean surface air temperature has risen by about 0.75 K. Due to feedbacks -- including the snow/ice albedo feedback -- the warming in the Arctic is expected to proceed at a faster rate than the global average. Climate model simulations suggest that this Arctic amplification produces warming that is two to three times larger than the global mean. Understanding the Arctic amplification is essential for projections of future Arctic climate including sea ice extent and melting of the Greenland ice sheet. We use the temperature records from the Arctic stations to show that (a) the Arctic amplification is larger at latitudes above 700 N compared to those within 64-70oN belt, and that, surprisingly; (b) the ratio of the Arctic to global rate of temperature change is not constant but varies on the decadal timescale. This time dependence will affect future projections of climate changes in the Arctic.

  17. Vegetables, fruit, and cancer prevention: a review.

    Science.gov (United States)

    Steinmetz, K A; Potter, J D

    1996-10-01

    In this review of the scientific literature on the relationship between vegetable and fruit consumption and risk of cancer, results from 206 human epidemiologic studies and 22 animal studies are summarized. The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon. The types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables, followed by allium vegetables, carrots, green vegetables, cruciferous vegetables, and tomatoes. Substances present in vegetables and fruit that may help protect against cancer, and their mechanisms, are also briefly reviewed; these include dithiolthiones, isothiocyanates, indole-3-carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, vitamin C, D-limonene, lutein, folic acid, beta carotene, lycopene, selenium, vitamin E, flavonoids, and dietary fiber. Current US vegetable and fruit intake, which averages about 3.4 servings per day, is discussed, as are possible noncancer-related effects of increased vegetable and fruit consumption, including benefits against cardiovascular disease, diabetes, stroke, obesity, diverticulosis, and cataracts. Suggestions for dietitians to use in counseling persons toward increasing vegetable and fruit intake are presented.

  18. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    Science.gov (United States)

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-09-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

  19. The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams

    Directory of Open Access Journals (Sweden)

    J. R. Larouche

    2015-03-01

    Full Text Available In the Alaskan Arctic, rapid climate change is increasing the frequency of disturbance including wildfire and permafrost collapse. These pulse disturbances may influence the delivery of dissolved organic carbon (DOC to aquatic ecosystems, however the magnitude of these effects compared to the natural background variability of DOC at the watershed scale is not well known. We measured DOC quantity, composition, and biodegradability from 14 river and stream reaches (watershed sizes ranging from 1.5–167 km2 some of which were impacted by permafrost collapse (thermokarst and fire. We found that region had a significant impact on quantity and biodegradability of DOC, likely driven by landscape and watershed characteristics such as lithology, soil and vegetation type, elevation, and glacial age. However, contrary to our hypothesis, we found that streams disturbed by thermokarst and fire did not contain significantly altered labile DOC fractions compared to adjacent reference waters, potentially due to rapid ecosystem recovery after fire and thermokarst as well as the limited spatial extent of thermokarst. Overall, biodegradable DOC ranged from 4 to 46% and contrary to patterns of DOC biodegradability in large Arctic rivers, seasonal variation in DOC biodegradability showed no clear pattern between sites, potentially related to stream geomorphology and position along the river network. While thermokarst and fire can alter DOC quantity and biodegradability at the scale of the feature, we conclude that tundra ecosystems are resilient to these types of disturbance.

  20. Rich and cold: diversity, distribution and drivers of fungal communities in patterned-ground ecosystems of the North American Arctic.

    Science.gov (United States)

    Timling, I; Walker, D A; Nusbaum, C; Lennon, N J; Taylor, D L

    2014-07-01

    Fungi are abundant and functionally important in the Arctic, yet comprehensive studies of their diversity in relation to geography and environment are not available. We sampled soils in paired plots along the North American Arctic Transect (NAAT), which spans all five bioclimatic subzones of the Arctic. Each pair of plots contrasted relatively bare, cryoturbated patterned-ground features (PGFs) and adjacent vegetated between patterned-ground features (bPGFs). Fungal communities were analysed via sequencing of 7834 ITS-LSU clones. We recorded 1834 OTUs - nearly half the fungal richness previously reported for the entire Arctic. These OTUs spanned eight phyla, 24 classes, 75 orders and 120 families, but were dominated by Ascomycota, with one-fifth belonging to lichens. Species richness did not decline with increasing latitude, although there was a decline in mycorrhizal taxa that was offset by an increase in lichen taxa. The dominant OTUs were widespread even beyond the Arctic, demonstrating no dispersal limitation. Yet fungal communities were distinct in each subzone and were correlated with soil pH, climate and vegetation. Communities in subzone E were distinct from the other subzones, but similar to those of the boreal forest. Fungal communities on disturbed PGFs differed significantly from those of paired stable areas in bPGFs. Indicator species for PGFs included lichens and saprotrophic fungi, while bPGFs were characterized by ectomycorrhizal and pathogenic fungi. Our results suggest that the Arctic does not host a unique mycoflora, while Arctic fungi are highly sensitive to climate and vegetation, with potential to migrate rapidly as global change unfolds.

  1. [American cutaneous leishmaniasis in municipalities in the northwestern region of Paraná State: use of remote sensing for analysis of vegetation types and places with disease occurrence].

    Science.gov (United States)

    Arraes, Sandra Mara Alessi Aristides; Veit, Renata Tonon; Bernal, Marcos Vinícius Zandonadi; Becker, Tânia Cristina Alexandrino; Nanni, Marcos Rafael

    2008-01-01

    American cutaneous leishmaniasis, an endemic disease in the northwestern region of Paraná, Brazil, is transmitted by phlebotomines to man and animals like dogs, armadillos, opossums and wild rodents. This disease has been occurring in places where forests have been felled and on the banks of rivers and lakes with arboreal vegetation, where man comes into contact with infected insects. This disease is a public health problem because of the occurrence of epidemic outbreaks throughout Paraná. Because of the importance of finding out about endemic areas, this study used epidemiological file data on patients attended between 1999 and 2004. These data were correlated with areas of forest felling that were identified by means of satellite remote sensing techniques and products. The results showed that the occurrences of cases in the municipalities of this region coincided with the presumed likely areas for patient infection.

  2. Effects of pomegranate and pomegranate-apple blend juices on the growth characteristics of Alicyclobacillus acidoterrestris DSM 3922 type strain vegetative cells and spores.

    Science.gov (United States)

    Molva, Celenk; Baysal, Ayse Handan

    2015-05-04

    The present study examined the growth characteristics of Alicyclobacillus acidoterrestris DSM 3922 vegetative cells and spores after inoculation into apple, pomegranate and pomegranate-apple blend juices (10, 20, 40 and 80%, v/v). Also, the effect of sporulation medium was tested using mineral [Bacillus acidoterrestris agar (BATA) and Bacillus acidocaldarius agar (BAA)] and non-mineral containing media [potato dextrose agar (PDA) and malt extract agar (MEA)]. The juice samples were inoculated separately with approximately 10(5)CFU/mL cells or spores from different sporulation media and then incubated at 37°C for 336 h. The number of cells decreased significantly with increasing pomegranate juice concentration in the blend juices and storage time (ppomegranate juices, respectively while the cell counts attained approximately 7.17 log CFU/mL in apple juice after 336 h. On the other hand, the cell growth was inhibited for a certain time, and then the numbers started to increase after 72 and 144 h in 10% and 20% blend juices, respectively. After 336 h, total population among spores produced on PDA, BATA, BAA and MEA indicated 1.49, 1.65, 1.67, and 1.28 log reductions in pomegranate juice; and 1.51, 1.38, 1.40 and 1.16 log reductions in 80% blend juice, respectively. The inhibitory effects of 10%, 20% and 40% blend juices varied depending on the sporulation media used. The results obtained in this study suggested that pomegranate and pomegranate-apple blend juices could inhibit the growth of A. acidoterrestris DSM 3922 vegetative cells and spores.

  3. In Brief: Arctic Report Card

    Science.gov (United States)

    Showstack, Randy

    2009-11-01

    The 2009 annual update of the Arctic Report Card, issued on 22 October, indicates that “warming of the Arctic continues to be widespread, and in some cases dramatic. Linkages between air, land, sea, and biology are evident.” The report, a collaborative effort of 71 national and international scientists initiated in 2006 by the Climate Program Office of the U.S. National Oceanic and Atmospheric Administration (NOAA), highlights several concerns, including a change in large-scale wind patterns affected by the loss of summer sea ice; the replacement of multiyear sea ice by first-year sea ice; warmer and fresher water in the upper ocean linked to new ice-free areas; and the effects of the loss of sea ice on Arctic plant, animal, and fish species. “Climate change is happening faster in the Arctic than any other place on Earth-and with wide-ranging consequences,” said NOAA administrator Jane Lubchenco. “This year“s Arctic Report Card underscores the urgency of reducing greenhouse gas pollution and adapting to climate changes already under way.”

  4. Landscape Level Analyses of Vegetation Cover in Northern Alaska

    Science.gov (United States)

    Botting, T.; Hollister, R. D.

    2013-12-01

    Many International Tundra Experiment (ITEX) studies have been conducted to identify vegetation changes due to warming. However, knowledge gaps remain. For example, most of these studies are conducted at the plot level, not the landscape level, potentially masking larger scale impacts of climate change. An Arctic Systems Science (ARCSS) grid was established in Atqasuk, Alaska and Barrow, Alaska in the mid 1990's. In 2010, approximately 100 untreated vegetation plots were implemented at each grid site. These vegetation plots are 1 meter squared, spaced 100 meters apart, and span 1 kilometer squared. Each vegetation plot represents 100 square meters along the grid. This project will focus on how vegetation cover has changed at the landscape level, using the point frame method, from 2010 to 2013. Preliminary data analysis indicates that in Atqasuk, graminoids, deciduous shrubs, and evergreen shrubs show increased cover, while little change has occurred with bryophytes, forbs and lichens. In Barrow, graminoids, lichens and forbs have shown an increase in cover, while little change has occurred with bryophytes and deciduous shrubs. At both sites, graminoids represent the greatest increase in cover of all growth forms analyzed. This study will be the foundation for later work, with the purpose of predicting what ARCSS grid vegetation community compositions will be in the future. These expectations will be based on anticipated warming data from ITEX passively warmed vegetation plots. This will be the first time that ITEX vegetation warming research is applied to landscape level research in Barrow and Atqasuk.

  5. Cretaceous Arctic magmatism: Slab vs. plume? Or slab and plume?

    Science.gov (United States)

    Gottlieb, E. S.; Miller, E. L.; Andronikov, A. V.; Brumley, K.; Mayer, L. A.; Mukasa, S. B.

    2010-12-01

    radial dikes that emanate from the proposed locus of the HALIP on the Alpha Ridge (Buchan and Ernst, 2006). 112, 100, and 83 Ma (40Ar/39Ar) basaltic lavas dredged in 2008 from the northwestern edge of the Canada Basin bear geochemical similarity to HALIP magmatism on Ellesmere Island and Franz Josef Land. Geochemical data on terrestrial HALIP and dredged basalts is indicative of an evolving plume-related origin for basaltic magmatism by 112 Ma. No matter how the AB is reconstructed, its pre-mid-Cretaceous configuration requires that terrestrial exposures of the HALIP were much closer to the actively subducting and extending Russian-Alaskan margin. Likewise, the temporal overlap of the onset of extension along the Russian-Alaskan segment of the Arctic margin (~135-120 Ma) with eruption of Barremian-Aptian HALIP lavas needs to be considered in models for the opening of the AB. This geochronologic compilation and summary highlights the facts that before the opening of the AB, the HALIP originated in a back arc position with respect to slab-related magmatism along the Pacific margin of the Arctic and that the two types of magmatism overlap in age and were once closer in space.

  6. Increasing shrub abundance and N addition in Arctic tundra affect leaf and root litter decomposition differently

    Science.gov (United States)

    McLaren, J.; van de Weg, M. J.; Shaver, G. R.; Gough, L.

    2013-12-01

    decomposition rates; only Ledum roots decomposed slower than the other three species and the overall root litter respiration rates increased with the duration of the experiment (in contrast to leaf liter respiration). A fertilized environment had no effect on overall weight loss of the leaf or root litter within the time of our study, but leaf and root litter respiration rates were significantly larger at the end of the study in the fertilized tundra.The temperature sensitivity of leaf respiration was significantly lower for leaf litter respiration than root liter respiration after fist snow melt, but this difference disappeared throughout the first growing season and neither was influenced by species composition or fertilization with N+P. Overall, our results suggest that as arctic vegetation shifts towards shrub-dominated tundra, both species composition and seasonally dependent processes will determine effects of changing vegetation types on carbon turnover in arctic ecosystems.

  7. Weed Identification and Control in Vegetable Crops.

    Science.gov (United States)

    Ferretti, Peter A., Comp.

    This agriculture extension service publication from Pennsylvania State University examines weed control and identification in vegetable crops. Contents include: (1) Types of weeds; (2) Reducing losses caused by weeds, general control methods and home garden weed control; (3) How herbicides are used; (4) Specific weeds in vegetable plantings; and…

  8. Modelling CH4 emissions from arctic wetlands: effects of hydrological parameterization

    Directory of Open Access Journals (Sweden)

    P. M. Crill

    2007-09-01

    Full Text Available This study compares the CH4 fluxes from two arctic wetland sites of different annual temperatures during 2004 to 2006. The PEATLAND-VU model was used to simulate the emissions. The CH4 module of PEATLAND-VU is based on the Walter-Heimann model. The first site is located in northeast Siberia, Indigirka lowlands, Kytalyk reserve (70° N, 147° E in a continuous permafrost region with mean annual temperatures of –14.3°C. The other site is Stordalen mire in the eastern part of Lake Torneträsk (68° N, 19° E, ten kilometres east of Abisko, northern Sweden. It is located in a discontinuous permafrost region. Stordalen has a sub arctic climate with a mean annual temperature of –0.7°C. Model input consisted of observed temperature, precipitation and snow cover data. In all cases, modelled CH4 emissions show a direct correlation between variations in water table and soil temperature variations. The differences in CH4 emissions between the two sites are caused by different climate, hydrology, soil physical properties, vegetation type and NPP. For Kytalyk the simulated CH4 fluxes show similar trends during the growing season, having average values for 2004 to 2006 between 1.29–2.09 mg CH4 m−2 h−1. At Stordalen the simulated fluxes show a slightly lower average value for the same years (3.52 mg CH4 m−2 h−1 than the observed 4.7 mg CH4 m−2 h−1. The effect of the longer growing season at Stordalen is simulated correctly. Our study shows that modelling of arctic CH4 fluxes is improved by adding a relatively simple hydrological model that simulates the water table position from generic weather data. We conclude that CH4 fluxes at these sites are less sensitive to temperature variation than to water table variations. Furthermore, parameter uncertainty at site level in wetland CH4 process models is an important factor in large scale modelling of CH4 fluxes.

  9. Arctic Landscape Within Reach

    Science.gov (United States)

    2008-01-01

    This image, one of the first captured by NASA's Phoenix Mars Lander, shows flat ground strewn with tiny pebbles and marked by small-scale polygonal cracking, a pattern seen widely in Martian high latitudes and also observed in permafrost terrains on Earth. The polygonal cracking is believed to have resulted from seasonal contraction and expansion of surface ice. Phoenix touched down on the Red Planet at 4:53 p.m. Pacific Time (7:53 p.m. Eastern Time), May 25, 2008, in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude. This image was acquired at the Phoenix landing site by the Surface Stereo Imager on day 1 of the mission on the surface of Mars, or Sol 0, after the May 25, 2008, landing. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. Arctic hydrology and meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D.L.

    1988-01-01

    The behavior of arctic ecosystems is directly related to the ongoing physical processes of heat and mass transfer. Furthermore, this system undergoes very large fluctuations in the surface energy balance. The buffering effect of both snow and the surface organic soils can be seen by looking at the surface and 40 cm soil temperatures. The active layer, that surface zone above the permafrost table, is either continually freezing or thawing. A large percentage of energy into and out of a watershed must pass through this thin veneer that we call the active layer. Likewise, most water entering and leaving the watershed does so through the active layer. To date, we have been very successful at monitoring the hydrology of Imnavait Creek with special emphasis on the active layer processes. The major contribution of this study is that year-round hydrologic data are being collected. An original objective of our study was to define how the thermal and moisture regimes within the active layer change during an annual cycle under natural conditions, and then to define how the regime will be impacted by some imposed terrain alteration. Our major analysis of the hydrologic data sets for Imnavait Creek have been water balance evaluations for plots during snowmelt, water balance for the watershed during both rainfall and snowmelt, and the application of a hydrologic model to predict the Imnavait Creek runoff events generated by both snowmelt and rainfall.

  11. Uncertainties in Arctic Precipitation

    Science.gov (United States)

    Majhi, I.; Alexeev, V. A.; Cherry, J. E.; Cohen, J. L.; Groisman, P. Y.

    2012-12-01

    Arctic precipitation is riddled with measurement biases; to address the problem is imperative. Our study focuses on comparison of various datasets and analyzing their biases for the region of Siberia and caution that is needed when using them. Five sources of data were used ranging from NOAA's product (RAW, Bogdanova's correction), Yang's correction technique and two reanalysis products (ERA-Interim and NCEP). The reanalysis dataset performed better for some months in comparison to Yang's product, which tends to overestimate precipitation, and the raw dataset, which tends to underestimate. The sources of bias vary from topography, to wind, to missing data .The final three products chosen show higher biases during the winter and spring season. Emphasis on equations which incorporate blizzards, blowing snow and higher wind speed is necessary for regions which are influenced by any or all of these factors; Bogdanova's correction technique is the most robust of all the datasets analyzed and gives the most reasonable results. One of our future goals is to analyze the impact of precipitation uncertainties on water budget analysis for the Siberian Rivers.

  12. Comparative analysis of two vegetation types and its ecotone, Miranda - MS Análise comparativa de duas formações vegetacionais e de seu ecótono, Miranda - MS

    Directory of Open Access Journals (Sweden)

    Mariana Chaves Mota

    2011-12-01

    Full Text Available The Pantanal consists of different vegetation types, including the Paratudal, a monodominat floodable savanna, and Riparian vegetation. This study aimed to analyze diversity and similarity in samples ofthese two vegetations, and its ecotone. The study was developed in the region of Passo do Lontra, at the Miranda river margins. Five plots 10 x 10m, were allocated in each area, where all individuals above 1m height were counted and identified. Nine hundred and thirteen individuals were registered, distributed in 70 taxa, of which 60 were identified in species level. The Shannon diversity index (H’ was 2.715 with Pielou Eveness (J’ of 0.806 in Paratudal, 3.010 and 0.835 in Riparian vegetation, and 2.739 and 0.797 in ecotone, respectively. These results show highest diversity in the Riparian vegetation, as expected, since the Paratudal’s ambient conditions are more restrictive. The floristic similarity between the Paratudal and the Riparian vegetation, according to the Sorensen index, was of 0.2, what distinguish both environments. Therefore, this study evidences the distinction among Riparian vegetation andParatudal, as well the existence of an intermediary values with ecotone. O Pantanal é constituído por diferentes formações vegetacionais, entre elas o Paratudal e a Mata Ciliar. Este trabalho objetivou analisar comparativamente essas duas formações, e o ecótono entre elas, quanto à diversidade e similaridade. O estudo foi desenvolvido na região do Passo do Lontra, às margens do rio Miranda, MS. Foram estabelecidas cinco parcelas de 10 x 10m em cada área e nelas todos os indivíduos acima de 1m de altura foram contados e identificados. Foram registrados 913 indivíduos, distribuídos em 70 taxa, dos quais 60 foram identificados em nível de espécie. O índice de diversidade de Shannon (H’ foi 2,715 com equidade de Pielou (J’ de 0,806 no Paratudal; 3,010 e 0,835 na MataCiliar; e 2,739 e 0,797 no ecótono, respectivamente

  13. Intercomparison of satellite-derived cloud analyses for the Arctic Ocean in spring and summer

    Science.gov (United States)

    Mcguffie, K.; Barry, R. G.; Schweiger, A.; Newell, J.; Robinson, D. A.

    1988-01-01

    Several methods of deriving Arctic cloud information, primarily from satellite imagery, have been intercompared. The comparisons help in establishing what cloud information is most readily determined in polar regions from satellite data analysis. The analyses for spring-summer conditions show broad agreement, but subjective errors affecting some geographical areas and cloud types are apparent. The results suggest that visible and thermal infrared data may be insufficient for adequate cloud mapping over some Arctic surfaces.

  14. Sensitivity of vegetation indices to different burn and vegetation ratios using LANDSAT-5 satellite data

    Science.gov (United States)

    Pleniou, M.; Koutsias, N.

    2013-08-01

    The application of vegetation indices is a very common approach in remote sensing of burned areas to either map the fire scar or estimate burn severity since they minimize the effect of exogenous factors and enhance the correlation with the internal parameters of vegetation. In a recent study we found that the original spectral channels, based on which these indices are estimated, are sensitive to external parameters of the vegetation as for example the spectral reflectance of the background soil. In such cases, the influence of the soil in the reflectance values is different in the various spectral regions depending on its type. These problems are further enhanced by the non-homogeneous pixels, as created from fractions of different types of land cover. Parnitha (Greece), where a wildfire occurred on July 2007, was established as test site. The purpose of this work is to explore the sensitivity of vegetation indices when used to estimate and map different fractions of fire-scorched (burned) and non fire-scorched (vegetated) areas. IKONOS, a very high resolution satellite imagery, was used to create a three-class thematic map to extract the percentages of vegetation, burned surfaces, and bare soil. Using an overlaid fishnet we extracted samples of completely "burned", completely "vegetated" pixels and proportions with different burn/vegetation ratios (45%-55% burned - 45%-55% vegetation, 20%-30% burned - 70%- 80% vegetation, 70%-80% burned - 20%-30% vegetation). Vegetation indices were calculated (NDVI, IPVI, SAVI) and their values were extracted to characterize the mentioned classes. The main findings of our recent research were that vegetation indices are less sensitive to external parameters of the vegetation by minimizing external effects. Thus, the semi-burned classes were spectrally more consistent to their different fractions of scorched and non-scorched vegetation, than the original spectral channels based on which these indices are estimated.

  15. Shrubs in the cold : interactions between vegetation, permafrost and climate in Siberian tundra

    NARCIS (Netherlands)

    Blok, D.

    2011-01-01

    The Arctic is experiencing strong increases in air temperature during the last decades. High-latitude tundra regions are very responsive to changes in temperature and may cause a shift in tundra vegetation composition towards greater dominance of deciduous shrubs. With increasing deciduous shrub cov

  16. Analysis of Adenoid Vegetation Children with Different Types of Tympanograms and Secretory Otitis Media%腺样体肥大患儿鼓室导抗图与分泌性中耳炎的关系探讨

    Institute of Scientific and Technical Information of China (English)

    高永平; 田从哲; 刘会清; 孟胜环; 刘海燕

    2013-01-01

    目的:探讨腺样体肥大患儿的不同鼓室导抗图与分泌性中耳炎的关系。方法回顾性分析2009年1月~2011年6月收治的328例腺样体肥大患儿的临床资料,分析统计分泌性中耳炎的发病例(耳)数及声导抗测试诊断分泌性中耳炎的阳性率。结果328例腺样体肥大患儿中有104例(169耳)最终经鼓膜穿刺或鼓膜置管确诊为分泌性中耳炎(31.71%,104/328),其中鼓室导抗图为B型者89例152耳,最终确诊为分泌性中耳炎者为86例147耳,阳性率为96.71%(147/152);鼓室导抗图为C型(负压在-150 daPa以上)者33例49耳,最终确诊为分泌性中耳炎者为16例20耳,阳性率为40.82%(20/49);鼓室导抗图为A s型者2例2耳最终均确诊为分泌性中耳炎。结论腺样体肥大患儿无论有无听力下降主诉,均应行声导抗测试,B型鼓室导抗图对鼓室积液判断的准确率最高,C型次之,As型也有鼓室积液的可能。%Objective To explore the relationship between adenoid vegetation children with different types of tympanograms and secretory otitis media in children and diagnosis of secretory otitis media .Methods A retrospec-tive study was carried out among 328 cases with adenoid vegetation in children ,including simple adenoid vegetation and associated with chronic tonsillitis and tonsillar hypertrophy ,from August 2010 to May 2012 .The incidence of secretory otitis media and outcomes of tympanometry for the diagnosis were analyzed .Results 104 cases were diag-nosed with secretory otitis media by tympanic membrane puncture or tympanostomy tube in 328 cases with adenoid vegetation (32 .31% );86 cases (147 ears) were finally diagnosed as secretory otitis media among 89 cases (152 ears) with type B tympanogram (147/152 ,96 .63% );16 cases (20 ears) were finally diagnosed secretory otitis media among 33 cases (49 ears) with type C tympanogram (20/49 ,40 .82% );2 cases (2 ears) with

  17. Slow recovery of High Arctic heath communities from nitrogen enrichment.

    Science.gov (United States)

    Street, Lorna E; Burns, Nancy R; Woodin, Sarah J

    2015-04-01

    Arctic ecosystems are strongly nutrient limited and exhibit dramatic responses to nitrogen (N) enrichment, the reversibility of which is unknown. This study uniquely assesses the potential for tundra heath to recover from N deposition and the influence of phosphorus (P) availability on recovery. We revisited an experiment in Svalbard, established in 1991, in which N was applied at rates representing atmospheric N deposition in Europe (10 and 50 kg N ha(-1)  yr(-1) ; 'low' and 'high', respectively) for 3-8 yr. We investigated whether significant effects on vegetation composition and ecosystem nutrient status persisted up to 18 yr post-treatment. Although the tundra heath is no longer N saturated, N treatment effects persist and are strongly P-dependent. Vegetation was more resilient to N where no P was added, although shrub cover is still reduced in low-N plots. Where P was also added (5 kg P ha(-1)  yr(-1) ), there are still effects of low N on community composition and nutrient dynamics. High N, with and without P, has many lasting impacts. Importantly, N + P has caused dramatically increased moss abundance, which influences nutrient dynamics. Our key finding is that Arctic ecosystems are slow to recover from even small N inputs, particularly where P is not limiting.

  18. Detection of Vehicle Tracks and Vegetation Damages Caused by use of Snowmobiles in the Longyearbyen Area on Svalbard using Unmanned Aircraft

    Science.gov (United States)

    Storvold, R.; Karlsen, S. R.; Solbø, S. A.; Johansen, B.; Johansen, K.; Høgda, K. A.; Tømmervik, H.; Zmarz, A.; Joly, D.

    2013-12-01

    The study area in the surroundings of Longyearbyen on Svalbard, Arctic Norway, located at 71.2°N and 16°E is characterized by dry Arctic climate with a snow season of more than eight months, annual precipitation of less than 200mm, and a mean July temperature of about 6°C. Longyearbyen is the main settlement on Svalbard, with about 2000 inhabitants. During the last two decades the number of snowmobiles have increased from a few hundred to a number almost equals the number of inhabitants, and snowmobile trips are today the one of the main leisure activities. In addition, thousands of tourist visits every spring, and many of these go on organized snowmobile trips. Due to the often thin snow cover, and use of snowmobile even during the spring snow melt in May and early June, the rapid growth in use of snowmobile has made some damage to the vegetation. Damage on the fragile vegetation caused by the skids and belts of the snowmobile can be observed in most parts of the Adventdalen valley, close to Longyearbyen. The main aim of this study is to explore the feasibility and accuracy of using data from Unmanned Aircraft Systems (UAS) to identify vehicle tracks and damages on vegetation caused by the use of snowmobiles. Use of UAS give the opportunity to carry out research in a manner that minimizes the environmental footprint of the research activities. Small unmanned aircraft, combining both fixed wing multi rotor types allow us to collect image data for vegetation mapping without having any personnel walking into the field disturbing the sensitive High Arctic ecosystems. UAS used here are inexpensive and simple to operate. They are being developed with the goal of providing airborne capabilities for scientists at an affordable cost. The aircraft were instrumented with a normal Canon Powershot S100 RGB compact camera and a modified Canon Powershot SX230 NDVI camera. The fixed wing aircraft was taking pictures from 100 meters altitude with ground resolution of 2.5 cm

  19. Global change and climate-vegetation classification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three phrases of the quantitative study of climate-vegetation classification and their characteristics are presented based on the review of advance in climate-vegetation interaction, a key issue of "global change and terrestrial ecosystems (GCTE)" which is the core project of International Geosphere-Biosphere Programme (IGBP): (ⅰ) characterized by the correlation between natural vegetation types and climate; (ⅱ) characterized by climatic indices which have obviously been restricted to plant ecophysiology; (ⅲ) characterized by coupling both structure and function of vegetation. Thus, the prospective of climate-vegetation classification for global change study in China was proposed, especially the study coupling climate-vegetation classification models with atmospheric general circulation models (GCMs) was emphasized.

  20. Terrestrial transect study on driving mechanism of vegetation changes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In terms of Chinese climate-vegetation model based on the classification of plant functional types, to- gether with climatic data from 1951 to 1980 and two future climatic scenarios (SRES-A2 and SRES-B2) in China from the highest and the lowest emission scenarios of greenhouse gases, the distribution patterns of vegetation types and their changes along the Northeast China Transect (NECT) and the North-South Transect of Eastern China (NSTEC) were simulated in order to understand the driving mechanisms of vegetation changes under climatic change. The results indicated that the vegetation distribution patterns would change significantly under future climate, and the major factors driving the vegetation changes were water and heat. However, the responses of various vegetation types to the changes in water and heat factors were obviously different. The vegetation changes were more sensi- tive to heat factors than to water factors. Thus, in the future climate warming will significantly affect vegetation distribution patterns.

  1. Circum-Arctic Map Compilation

    Science.gov (United States)

    Saltus, Richard W.; Gaina, Carmen

    2007-05-01

    Second Workshop of the Circum-Arctic Geophysical Maps Project, Trondheim, Norway, 12-13 February 2007 The eyes of the world are increasingly focused on the polar regions. Exploration and assessment of energy and mineral resources for the growing world economy are moving to high-latitude frontier areas. The effects of climatic changes are particularly pronounced at these ends of the Earth and have already attracted worldwide attention and concern. Many recent articles related to the International Polar Year underscore the importance of even basic mapping of the Arctic and Antarctic.

  2. Influence of Watering with an enriched solution of surfactants on the soil properties and vegetation growth. Experimental model with two types of soils: district cambisol and calcaricum cambisol; Influencia del riego con solucion enriquecida en tensoactivos sobre las propiedades del suelo y el desarrollo vigetal

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Caravaca, M. T.; Crespo Alia, M. A. [Universidad Complutense. Madrid (Spain)

    2000-07-01

    A study done on the the influence of watering with an enriched solution of surfactants on the soil properties and vegetation growth using an experimental model with two types of soils, each one with different characteristic: district Cambisol and calcaricum Cambisol. The results show significant differences in conductivity, organic carbon content, clay content and in phosphates. As well, the sodium enrichment of the adjuvants components of the detergent employed significantly influence the content of free clay and the SAR values. The chosen vegetation was seen to be affected in these areas: sprouting, vegetal mass and principally in the amount of calcium foliage. (Author) 18 refs.

  3. Arctic West and North of Svalbard

    Energy Technology Data Exchange (ETDEWEB)

    Sundvor, E.; Austegard, A. (Bergen Univ. (Norway)) Myhre, A.M.; Eldholm, O. (Oslo Univ., (Norway) Dept. of Geology)

    1982-01-01

    Recent multichannel seismic data have revealed that the Svalbard passive margin has undergone a complex geological history which largely reflects the plate tectonic evolution of the Greenland Sea and the Arctic Ocean. On the western margin the continent-ocean boundary is located at or close to the Hornsund Fault Zone. In the late Paleocene/Early Eocene, the region between Svalbard and Northeast Greenland was subjected to regional shear movements associated with a transform system between the young Lofoten-Greenland Basin and the Arctic Ocean. Approximately 50My ago the spreading axis migrated northeastwards forming the passive margin between Bear Island and 76.5degN. At the time of the main reorganization of the plate motion the northern margin evolved and a continental fragment was possibly cut off from the Svalbard margin, appearing, today, as the submarine ridge associated with the Hovgaard Fracture Zone. The northern Svalbard margin is of a rifted type, though the seismic results indicate two structurally different regions: The Yermak Plateau and the Hinlopen Margin. A major problem in understanding the geology and evolution of the Yermak Plateau is the nature of the opaque acoustic basement. 12 drawings.

  4. High Arctic plant phenology is determined by snowmelt patterns but duration of phenological periods is fixed

    DEFF Research Database (Denmark)

    Semenchuk, Philipp R.; Gillespie, Mark A K; Rumpf, Sabine B.;

    2016-01-01

    The duration of specific periods within a plant's life cycle are critical for plant growth and performance. In the High Arctic, the start of many of these phenological periods is determined by snowmelt date, which may change in a changing climate. It has been suggested that the end of these periods...... controls phenology and phenological period duration in High Arctic Svalbard using a melt timing gradient from natural and experimentally altered snow depths. We investigated the response of early- and late-season phenophases from both vegetative and reproductive phenological periods of eight common species....... We found that all phenophases follow snowmelt patterns, irrespective of timing of occurrence, vegetative or reproductive nature. Three of four phenological period durations based on these phenophases were fixed for most species, defining the studied species as periodic. Periodicity can thus...

  5. Limnological characteristics of 56 lakes in the Central Canadian Arctic Treeline Region

    Directory of Open Access Journals (Sweden)

    John P. SMOL

    2003-02-01

    Full Text Available Measured environmental variables from 56 lakes across the Central Canadian Treeline Region exhibited clear limnological differences among subpolar ecozones, reflecting strong latitudinal changes in biome characteristics (e.g. vegetation, permafrost, climate. Principal Components Analysis (PCA clearly separated forested sites from tundra sites based on distinct differences in limnological characteristics. Increases in major ions and related variables (e.g. dissolved inorganic carbon, DIC were higher in boreal forest sites in comparison to arctic tundra sites. The higher values recorded in the boreal forest lakes may be indirectly related to differences in climatic factors in these zones, such as the degree of permafrost development, higher precipitation and runoff, duration of ice-cover on the lakes, and thicker and better soil development. Similar to trends observed in DIC, substantially higher values for dissolved organic carbon (DOC were measured in boreal forest lakes than in arctic tundra lakes. This was likely due to higher amounts of catchment-derived DOC entering the lakes from coniferous leaf litter sources. Relative to arctic tundra lakes, boreal forest lakes had higher nutrient concentrations, particularly total nitrogen (TN, likely due to warmer conditions, a longer growing season, and higher precipitation, which would enhance nutrient cycling and primary productivity. Results suggest that modern aquatic environments at opposite sides of the central Canadian arctic treeline (i.e. boreal forest and arctic tundra exhibit distinct differences in water chemistry and physical conditions. These limnological trends may provide important information on possible future changes with additional warming.

  6. Arctic Glass: Innovative Consumer Technology in Support of Arctic Research

    Science.gov (United States)

    Ruthkoski, T.

    2015-12-01

    The advancement of cyberinfrastructure on the North Slope of Alaska is drastically limited by location-specific conditions, including: unique geophysical features, remoteness of location, and harsh climate. The associated cost of maintaining this unique cyberinfrastructure also becomes a limiting factor. As a result, field experiments conducted in this region have historically been at a technological disadvantage. The Arctic Glass project explored a variety of scenarios where innovative consumer-grade technology was leveraged as a lightweight, rapidly deployable, sustainable, alternatives to traditional large-scale Arctic cyberinfrastructure installations. Google Glass, cloud computing services, Internet of Things (IoT) microcontrollers, miniature LIDAR, co2 sensors designed for HVAC systems, and portable network kits are several of the components field-tested at the Toolik Field Station as part of this project. Region-specific software was also developed, including a multi featured, voice controlled Google Glass application named "Arctic Glass". Additionally, real-time sensor monitoring and remote control capability was evaluated through the deployment of a small cluster of microcontroller devices. Network robustness was analyzed as the devices delivered streams of abiotic data to a web-based dashboard monitoring service in near real time. The same data was also uploaded synchronously by the devices to Amazon Web Services. A detailed overview of solutions deployed during the 2015 field season, results from experiments utilizing consumer sensors, and potential roles consumer technology could play in support of Arctic science will be discussed.

  7. Changing Arctic ecosystems: ecology of loons in a changing Arctic

    Science.gov (United States)

    Uher-Koch, Brian; Schmutz, Joel; Whalen, Mary; Pearce, John M.

    2014-01-01

    The U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative informs key resource management decisions for Arctic Alaska by providing scientific information on current and future ecosystem response to a changing climate. From 2010 to 2014, a key study area for the USGS CAE initiative has been the Arctic Coastal Plain of northern Alaska. This region has experienced rapid warming during the past 30 years, leading to the thawing of permafrost and changes to lake and river systems. These changes, and projections of continued change, have raised questions about effects on wildlife populations that rely on northern lake ecosystems, such as loons. Loons rely on freshwater lakes for nesting habitat and the fish and invertebrates inhabiting the lakes for food. Loons live within the National Petroleum Reserve-Alaska (NPR-A) on Alaska’s northern coast, where oil and gas development is expected to increase. Research by the USGS examines how breeding loons use the Arctic lake ecosystem and the capacity of loons to adapt to future landscape change.

  8. Reconstruction of Holocene palaeoclimate and environment in the Khatanga region, Russian Arctic

    Science.gov (United States)

    Syrykh, Ludmila; Nazarova, Larisa

    2016-04-01

    Arctic regions are highly sensitive to changes in temperature and precipitation, and their Late Quaternary environmental history is very important for understanding of present and past climate trends. Though the timing of Holocene climate change is well established for wide parts of the Northern Hemisphere, suitable palaeoenvironmental records are still scarce in the Russian Siberian Arctic. Taimyr Peninsula (74oN, 100oE) is the northernmost part of Russia. Thus, this area is probably one of the most promising regions for the reconstruction of the Late Quaternary environment in dependence on changes in global and regional climate and the atmospheric circulation. (Andreev et al., 2004).The area is characterized by a continental climate with long, severe winters, and short summers. The modern temperatures are about 10-14oC in July, and - 32 to 34oC in January. Annual precipitation ranges from about 300-400 mm at low elevations to about 600-800 mm on the western slopes of the Putorana Plateau (Atlas Arktiki, 1985). The frost-free period is ca. 35 days. Almost all the territory is underlain by continues permafrost. Periglacial landscape is dominated by tundra and taiga vegetation. Aquatic organisms such as chironomids (Insecta: Diptera) are recognized as the best biological indicators for quantifying past changes in air temperature or lake chemistry (Letter et al., 1997; Brooks and Birks, 2000; Battarbee, 2000; Massaferro and Brooks, 2002; Solovieva et al., 2005). Chironomids belong to the most abundant group of fresh-water bottom-dwelling macroinvertebrates. Because of their short life cycle, chironomids quickly adapt to environmental changes and in global scale the distribution and abundance of chironomids are mostly limited by temperature (Walker and Mathewes, 1987; Warwick, 1989; Hann et al., 1992; Walker et al., 1992). Larval head capsules of chironomids preserved in lake sediment as subfossils are abundant, identifiable and serve as indicators of the

  9. 搓动式沉水植物脱盐机脱盐效果的试验研究%Experimental Study on Desalting Efficacy of Rubbing Type Submerged Vegetation Desalting Machine

    Institute of Scientific and Technical Information of China (English)

    岳海军; 尚士友; 马清艳

    2014-01-01

    In the ecological management and resources development of Lake Wuliangsuhai , harvesting submerged vegeta-tion by mechanization method can decrease the accumulation of internal nutrient salts ; meliorate the water environment and transfer nutrient salts of nitrogen and phosphorus to achieve the purpose of eutrophication management and resources development .Design of rubbing type submerged vegetation desalting machine can decrease the amount of nutrient salts on the submerged plants after harvesting , improve the dainty of submerged vegetation feedstuff .Desalting submerged vegeta-tion shows that removal effect for about 9%-22 %moisture , 720 r/min rated rotation speed and 16 mm size of vibration sieve pore is the best and maximum removal rate reaches to 85 .45%, its desalting efficacy is better than beater pulveriz-er.Grey system theory model was set up to estimate desalting rate , average error is -1.66%, which lays theoretical foundation for its technology parameter optimization .%在乌梁素海的生态治理和资源开发中,以机械化方式收割沉水植物能够削减湖泊内各种营养盐的积累,转移各种氮磷营养盐,改善水质环境,实现湖泊富营养化治理和资源开发兼顾的目的。搓动式沉水植物脱盐机的研究设计,能够减少收割后沉水植物的含盐量,提高其作为沉水植物饲料的适口性。对晒干后的沉水植物进行脱盐试验表明:在含水率9%~22%,电动机额定转速720r/min,振动筛孔16mm 时,最大去除率达85.45%,较锤片式粉碎机去除效果好。利用灰色系统理论建立数学模型,预测不同工艺参数时的沉水植物饲料脱盐率,其平均误差为-1.66%,可为其工艺参数优化提供理论依据。

  10. Survival of rapidly fluctuating natural low winter temperatures by High Arctic soil invertebrates

    DEFF Research Database (Denmark)

    Convey, Peter; Abbandonato, Holly; Bergan, Frode;

    2015-01-01

    experienced at microhabitat level, few studies have explicitly set out to link field conditions experienced by natural multispecies communities with the more detailed laboratory ecophysiological studies of a small number of 'representative' species. This is particularly the case during winter, when snow cover...... microhabitats. To assess survival of natural High Arctic soil invertebrate communities contained in soil and vegetation cores to natural winter temperature variations, the overwintering temperatures they experienced were manipulated by deploying cores in locations with varying snow accumulation: No Snow...

  11. The Weird Vegetable Price

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Chinese Government faces the task of stabilizing vegetable prices to avoid steep increases and dips Fluctuations of vegetable prices in China have recently caused near panic in the domestic market.Purchase prices for farm produce are decreasing dramatically

  12. Total Vegetation 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These are polygons that contain vegetated pixels in the May, 2002 imagery from aerial overflight of the Grand Canyon. Vegetation was mapped between stage elevations...

  13. Procedures for Sampling Vegetation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines vegetation sampling procedures used on various refuges in Region 3. The importance of sampling the response of marsh vegetation to management...

  14. Sensitivity analysis of modelled responses of vegetation dynamics on the Tibetan Plateau to doubled CO2 and associated climate change

    Science.gov (United States)

    Qiu, Linjing; Liu, Xiaodong

    2016-04-01

    Increases in the atmospheric CO2 concentration affect both the global climate and plant metabolism, particularly for high-altitude ecosystems. Because of the limitations of field experiments, it is difficult to evaluate the responses of vegetation to CO2 increases and separate the effects of CO2 and associated climate change using direct observations at a regional scale. Here, we used the Community Earth System Model (CESM, version 1.0.4) to examine these effects. Initiated from bare ground, we simulated the vegetation composition and productivity under two CO2 concentrations (367 and 734 ppm) and associated climate conditions to separate the comparative contributions of doubled CO2 and CO2-induced climate change to the vegetation dynamics on the Tibetan Plateau (TP). The results revealed whether the individual effect of doubled CO2 and its induced climate change or their combined effects caused a decrease in the foliage projective cover (FPC) of C3 arctic grass on the TP. Both doubled CO2 and climate change had a positive effect on the FPC of the temperate and tropical tree plant functional types (PFTs) on the TP, but doubled CO2 led to FPC decreases of C4 grass and broadleaf deciduous shrubs, whereas the climate change resulted in FPC decrease in C3 non-arctic grass and boreal needleleaf evergreen trees. Although the combination of the doubled CO2 and associated climate change increased the area-averaged leaf area index (LAI), the effect of doubled CO2 on the LAI increase (95 %) was larger than the effect of CO2-induced climate change (5 %). Similarly, the simulated gross primary productivity (GPP) and net primary productivity (NPP) were primarily sensitive to the doubled CO2, compared with the CO2-induced climate change, which alone increased the regional GPP and NPP by 251.22 and 87.79 g C m-2 year-1, respectively. Regionally, the vegetation response was most noticeable in the south-eastern TP. Although both doubled CO2 and associated climate change had a

  15. Mining in the European Arctic

    NARCIS (Netherlands)

    van Dam, Karin; Scheepstra, Adriana; Gille, Johan; Stepien, Adam; Koivurova, Timo; Stepien, Adam; Koivurova, Timo; Kankaanpää, Paula

    2016-01-01

    The European Arctic has been recently experiencing an upsurge in mining activities. This is reflected in an on-going interest from the industry, regulators and the public. However, current and future prospects are highly sensitive to mineral price fluctuations. The EU is a major consumer and importe

  16. Arctic Basemaps In Google Maps

    DEFF Research Database (Denmark)

    Muggah, J.; Mioc, Darka

    2010-01-01

    The Ocean Mapping Group has been collecting data in the Arctic since 2003 and there are approximately 2,000 basemaps. In the current online storage format used by the OMG, it is difficult to view the data and users cannot easily pan and zoom. The purpose of this research is to investigate the adv...

  17. Arctic resources : a mechatronics opportunity

    Energy Technology Data Exchange (ETDEWEB)

    McKean, M.; Baiden, G. [Penguin Automated Systems Inc., Naughton, ON (Canada)

    2008-07-01

    This paper discussed the telerobotic mechatronics opportunities that exist to access mineral resources in the Arctic. The Mining Automation Project (MAP) determined that telerobotics could contribute to productivity gains while providing increased worker safety. The socio-economic benefits of advanced mechatronics for Arctic resource development are particularly attractive due to reduced infrastructure needs; operating costs; and environmental impacts. A preliminary analysis of mining transportation options by the authors revealed that there is a case for in-situ resource utilization (ISRU) for oil and gas processing to address resource development. The ISRU options build on concepts developed to support space exploration and were proposed to reduce or modify transportation loads to allow more sustainable and efficient Arctic resource development. Many benefits in terms of efficiency could be achieved by combining demonstrated mechatronics with ISRU because of the constrained transportation infrastructure in the Arctic. In the context of harsh environment operations, mechatronics may provide an opportunity for undersea resource facilities. 15 refs., 6 figs.

  18. Potential of C and X Band SAR for Shrub Growth Monitoring in Sub-Arctic Environments

    Directory of Open Access Journals (Sweden)

    Yannick Duguay

    2015-07-01

    Full Text Available The Arctic and sub-Arctic environments have seen a rapid growth of shrub vegetation at the expense of the Arctic tundra in recent decades. In order to develop better tools to assess and understand this phenomenon, the sensitivity of multi-polarized SAR backscattering at C and X band to shrub density and height is studied under various conditions. RADARSAT-2 and TerraSAR-X images were acquired from November 2011 to March 2012 over the Umiujaq community in northern Quebec (56.55°N, 76.55°W and compared to in situ measurements of shrub vegetation density and height collected during the summer of 2009. The results show that σ0 is sensitive to changes in shrub coverage up to 20% and is sensitive to changes in shrub height up to around 1 m. The cross-polarized backscattering (σ0 HV displays the best sensitivity to both shrub height and density, and RADARSAT-2 is more sensitive to shrub height, as TerraSAR-X tends to saturate more rapidly with increasing volume scattering from the shrub branches. These results demonstrate that SAR data could provide essential information, not only on Remote Sens. 2015, 7 9411 the spatial expansion of shrub vegetation, but also on its vertical growth, especially at early stages of colonization.

  19. Diversidad de reptiles en tres tipos de vegetación del estado de Hidalgo, México Diversity of reptiles in three vegetation types of the Hidalgo state, México

    Directory of Open Access Journals (Sweden)

    Raciel Cruz-Elizalde

    2012-06-01

    Full Text Available La zona sureste del estado de Hidalgo presenta diversos tipos de vegetación, como el bosque mesófilo de montaña, bosque de pino-encino y bosque de pino, con alta riqueza de reptiles. En este estudio, se analizó la diversidad alfa y beta de los reptiles en los 3 tipos de vegetación presentes en la zona sureste. Durante el periodo de recolección, de junio 2008 a agosto del 2009, se realizaron 12 salidas, 1 por mes, con duración de 3 días cada una. La diversidad de reptiles está compuesta por 25 especies, incluyendo un registro nuevo para el estado, la culebra Thamnophis scaliger. El bosque mesófilo de montaña (BMM presentó la mayor riqueza, con 15 especies, seguido del bosque de pino (BP, con 13, y el bosque de pino-encino (BPE, con 12. Las asociaciones realizadas entre el BMM-BP y BMM-BPE presentaron la más alta disimilitud en especies, y el menor valor fue para el BPE-BP. Este estudio muestra la riqueza y distribución de las especies de los reptiles en los diferentes tipos de vegetación del sureste del estado y presenta nuevos registros de especies para la entidad. El conocimiento de la riqueza de especies por tipos de vegetación de este estudio sienta las bases sobre la biodiversidad, lo que ayuda a plantear estudios dirigidos a la conservación de este grupo.The southeast of Hidalgo in Mexico includes various vegetation types, such as cloud forest, pine-oak forest and pine forest, all harbouring a high species richness of reptiles. In this study we analyzed the alpha and beta diversity of reptiles in 3 vegetation types in the southeast of the state. The field work period was from June 2008 to August 2009, comprising 12 sampling periods of 3 days, 1 per month. The diversity of reptiles is composed of 25 species, reporting the snake Thamnophis scaliger as a new record for the state. The cloud forest (CF has the highest richness, with 15 species, followed by pine forest (PF, with 13, and finally, the pine-oak forest (POF, with 12

  20. Dutch Vegetation Database (LVD)

    NARCIS (Netherlands)

    Hennekens, S.M.

    2011-01-01

    The Dutch Vegetation Database (LVD) hosts information on all plant communities in the Netherlands. This substantial archive consists of over 600.000 recent and historic vegetation descriptions. The data provide information on more than 85 years of vegetation recording in various habitats covering te

  1. Rock vegetation types of Danxia landform in Zhejiang Province%浙江省丹霞地貌岩生植被类型

    Institute of Scientific and Technical Information of China (English)

    沈年华; 李传磊; 王小德

    2011-01-01

    Rock vegetation of Danxia landform in Zhejiang Province consists of 5 categories, namely, shrub, shrub-grassland, meadow, vine and moss. Shrubs include Spiraea blumei, Exochorda racemosa, Vitex negundo var. Cannabifolia and Lagerstroemia indie a. Shrub-grasslands include Celtis biondii-Conandron ramondioides, Lespedeza bicolor-Neyraudia montana and Lespedeza bicolor-Sedum alfredii. Meadows include Neyraudia montana, Orostachys erubescens-Sedum polytrichoides, Conandron ramondioides, Selaginella moellendorffii, Pyrrosia lingua and Drynaria fortunei. Vines include Trachelospermum jasminoides, Ficus pumila and Parthenocissus tricuspidata. Mosses include Pogonatum inflexion, Campylopus umbellatus, Philonotis turneriana -Campylopus umbellatus and Bryum argenteum-Sematophyllum subhumile.%浙江省丹霞地貌岩生植被由灌丛、灌草丛、草甸、藤本和苔藓等5种类型组成.其中,灌丛有绣球绣线菊Spiraeab lumei灌丛、白鹃梅Exochorda racemosa灌丛、牡荆Vitex negundo vat.cannabifoli灌丛和紫薇Lagerstroemia indica灌丛;灌草丛有紫弹朴Celtis biondii-苦苣苔Conandron ramondioides灌草丛、胡枝子Lespedeza bicolor-山类芦Neyraudia montana灌草丛和小蜡Lespedeza bicolor-东南景天Sedum alfredii灌草丛;草甸有山类芦草甸、晚红瓦松Orostachys erubescens-藓状景天Sedum polytrichoides草甸、苦苣苔草甸、江南卷柏Selaginella moellendorffii草甸、石韦Pyrrosia lingua草甸和槲蕨Drynaria fortunei草甸;藤本类型有络石Trachelospermum jasminoides,薜荔Ficus pumila和爬山虎Parthenocissus tricuspidata;苔藓类型有东亚小金发藓Pogonatum inflexum,节茎曲柄藓Campylopus umbellatus、东亚泽藓Philonotis turneriana-节茎曲柄藓Campylopus umbellatus和真藓Bryum argenteum-矮锦藓Sematophyllum subhumile等.

  2. 基于 SolidWorks 的果蔬采摘基本构型库的设计%Design of Fruit and Vegetable Picking Mechanism Type Library System Based on Solidworks Software

    Institute of Scientific and Technical Information of China (English)

    夏红梅; 李志伟; 甄文斌; 赖基平

    2013-01-01

      少自由度串、并联机构构型是果蔬采摘机构构型综合的基本单元。为此,基于SolidWorks2008软件,采用尺寸驱动的设计方法,开发了少自由度串并联基本构型库系统。通过建立基本构型三维模型模板,创建机构性能属性信息数据库,利用VisualC++设计系统交互界面,编写API和ADO接口程序,实现基本机构构型参数化设计和属性信息查询修改功能,为果蔬采摘机构构型智能、高效和高质量综合提供设计资源平台。%Low-mobility serial or parallel mechanism is the basic unit for fruit and vegetable picking mechanism structur -al synthesis .Based on Solidworks 2008 software , low-mobility serial or parallel mechanism type library was developed by dimension driven design method .The basic mechanism type library system architecture was put forward .Through estab-lishing three-dimensional model template for basic mechanisms , creating mechanism performance data attribute informa-tion table , designing system interface with Visual C++software , writing API and ADO interface program , parameter de-sign and attribute information query modification function for basic mechanisms was realized .An intelligent , efficient , high quality design resource platform for fruit and vegetable picking mechanism structural synthesis was developed in the paper .

  3. The vegetation ecology of municipal Durban, Natal. Floristic classification

    Directory of Open Access Journals (Sweden)

    D. C. Roberts

    1993-12-01

    Full Text Available The vegetation of municipal Durban is classified according to the Braun-Blanquet method, using the PHYTOTAB program package. Five major vegetation types with 18 communities are described, as are the major environmental factors influencing vegetation composition and structure.

  4. Changing Arctic Ocean freshwater pathways.

    Science.gov (United States)

    Morison, James; Kwok, Ron; Peralta-Ferriz, Cecilia; Alkire, Matt; Rigor, Ignatius; Andersen, Roger; Steele, Mike

    2012-01-04

    Freshening in the Canada basin of the Arctic Ocean began in the 1990s and continued to at least the end of 2008. By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation. Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High--a characteristic peak in sea level atmospheric pressure--which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water. Limited observations have made this explanation difficult to verify, and observations of increasing freshwater content under a weakened Beaufort High suggest that other factors must be affecting freshwater content. Here we use observations to show that during a time of record reductions in ice extent from 2005 to 2008, the dominant freshwater content changes were an increase in the Canada basin balanced by a decrease in the Eurasian basin. Observations are drawn from satellite data (sea surface height and ocean-bottom pressure) and in situ data. The freshwater changes were due to a cyclonic (anticlockwise) shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Northern Hemisphere atmospheric circulation characterized by an increased Arctic Oscillation index. Our results confirm that runoff is an important influence on the Arctic Ocean and establish that the spatial and temporal manifestations of the runoff pathways are modulated by the Arctic Oscillation, rather than the strength of the wind-driven Beaufort Gyre circulation.

  5. Late snowmelt delays plant development and results in lower reproductive success in the High Arctic.

    Science.gov (United States)

    Cooper, Elisabeth J; Dullinger, Stefan; Semenchuk, Philipp

    2011-01-01

    In tundra areas where the growing season is short, any delay in the start of summer may have a considerable effect on plant development, growth and reproductive success. Climate models suggest long-term changes in winter precipitation in the Arctic, which may lead to deeper snow cover and a resultant delay in date of snow melt. In this paper, we investigated the role of snow depth and melt out date on the phenological development and reproductive success of vascular plants in Adventdalen, Svalbard (78° 10'N, 16° 06'E). Effects of natural variations in snow accumulation were demonstrated using two vegetation types (snow depth: meadow 21 cm, heath 32 cm), and fences were used to experimentally increase snow depth by over 1m. Phenological delay was greatest directly after snowmelt in the earlier phenological phases, and had the largest effect on the early development of those species which normally green-up early (i.e. Dryas, Papaver, Salix, Saxifraga). Compressed growing seasons and length of the reproductive period led to a reduced reproductive success in some of the study species. There were fewer flowers, fewer plots with dispersing seeds, and lower germination rates. This can have consequences for plant establishment and community composition in the long-term.

  6. Multinational Experiment 7. Maritime Security Region: The Arctic

    Science.gov (United States)

    2013-07-08

    currently valid OMB control number. 1. REPORT DATE 08 JUL 2013 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Multinational Experiment...thousand meters. Vast ledges of subsea land extend from the surrounding continents and underlie nearly two thirds of the ocean. The central Arctic... models had predicted. According to satellite measurements the minimum area of sea ice has decreased by more than 11 percent per decade over the last 30

  7. Analysis of the vegetation of the sandstone ridges (Ib land type of the north-eastern parts of the Mapungubwe National Park, Limpopo Province, South Africa

    Directory of Open Access Journals (Sweden)

    Albie R. Gotze

    2008-05-01

    Full Text Available The establishment of the Mapungubwe National Park has been an objective of several conservationists for many years. The ultimate objective is that this park should become a major component of a Transfrontier National Park shared by Botswana, Zimbabwe and South Africa. The aim of this study was to identify, classify and describe the plant communities present in the Ib land type of the park. Sampling was done by means of the Braun-Blanquet method. A total of 48 stratified random relevés were sampled in the Ib land type. All relevé data were imported into a TURBOVEG database, after which the numerical classification technique TWINSPAN was used as a first approximation. Subsequently, Braun-Blanquet procedures were used to refine data and a phytosociological table was constructed, using the visual editor, MEGATAB. Two plant communities and several subcommunities and variants were identified and described from the phytosociological table.

  8. The Submarine -- The Key to Winning an Arctic Conflict

    Science.gov (United States)

    2013-05-15

    Cold Horizons: Arctic Maritime Security Challenges.” 17 Franklyn Griffiths, Rob Huebert, and P. Whitney Lackenbauer, Canada and the Changing Arctic... Franklyn , Rob Huebert, and P. Whitney Lackenbauer. Canada and the Changing Arctic: Sovereignty, Security, and Stewardship. Waterloo, Ontario

  9. Climate change and the molecular ecology of Arctic marine mammals.

    Science.gov (United States)

    O'Corry-Crowe, Gregory

    2008-03-01

    Key to predicting likely consequences of future climate change for Arctic marine mammals is developing a detailed understanding of how these species use their environment today and how they were affected by past climate-induced environmental change. Genetic analyses are uniquely placed to address these types of questions. Molecular genetic approaches are being used to determine distribution and migration patterns, dispersal and breeding behavior, population structure and abundance over time, and the effects of past and present climate change in Arctic marine mammals. A review of published studies revealed that population subdivision, dispersal, and gene flow in Arctic marine mammals was shaped primarily by evolutionary history, geography, sea ice, and philopatry to predictable, seasonally available resources. A meta-analysis of data from 38 study units across seven species found significant relationships between neutral genetic diversity and population size and climate region, revealing that small, isolated subarctic populations tend to harbor lower diversity than larger Arctic populations. A few small populations had substantially lower diversity than others. By contrast, other small populations retain substantial neutral diversity despite extensive population declines in the 19th and 20th centuries. The evolutionary and contemporary perspectives gained from these studies can be used to model the consequences of different climate projections for individual behavior and population structure and ultimately individual fitness and population viability. Future research should focus on: (1) the use of ancient-DNA techniques to directly reconstruct population histories through the analysis of historical and prehistorical material, (2) the use of genomic technologies to identify, map, and survey genes that directly influence fitness, (3) long-term studies to monitor populations and investigate evolution in contemporary time, (4) further Arctic-wide, multispecies analyses

  10. Geologic Provinces of the Circum-Arctic, 2008 (north of the Arctic Circle)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile includes arcs and polygons that describe U.S. Geological Survey defined 33 geologic provinces of the Circum-Arctic (north of the Arctic Circle). Each...

  11. The effect of misleading surface temperature estimations on the sensible heat fluxes at a high Arctic site – the Arctic turbulence experiment 2006 on Svalbard (ARCTEX-2006

    Directory of Open Access Journals (Sweden)

    J. Bareiss

    2009-08-01

    Full Text Available The observed rapid climate warming in the Arctic requires improvements in permafrost and carbon cycle monitoring, accomplished by setting up long-term observation sites with high-quality in-situ measurements of turbulent heat, water and carbon fluxes as well as soil physical parameters in an Arctic landscape. But accurate quantification and well adapted parameterizations of turbulent fluxes in polar environments presents fundamental problems in soil-snow-ice-vegetation-atmosphere interaction studies. One of these problems is the accurate estimation of the surface or aerodynamic temperature T(0 required to force most of the bulk aerodynamic formula currently used. Results from the Arctic-Turbulence-Experiment (ARCTEX-2006 performed on Svalbard during the winter/spring transition 2006 helped to better understand the physical exchange and transport processes of energy. The existence of an untypical temperature profile close to the surface in the Arctic spring at Svalbard could be proven to be one of the major issues hindering estimation of the appropriate surface temperature. Thus, it is essential to adjust the set-up of measurement systems carefully when applying flux-gradient methods that are commonly used to force atmosphere-ocean/land-ice models. The results of a comparison of different sensible heat-flux parameterizations with direct measurements indicate that only the use of a hydrodynamic three-layer temperature-profile model achieves enough accuracy for heat flux calculations as it reliably reproduces the temporal variability of the surface temperature.

  12. The effect of misleading surface temperature estimations on the sensible heat fluxes at a high Arctic site – the Arctic Turbulence Experiment 2006 on Svalbard (ARCTEX-2006

    Directory of Open Access Journals (Sweden)

    J. Lüers

    2010-01-01

    Full Text Available The observed rapid climate warming in the Arctic requires improvements in permafrost and carbon cycle monitoring, accomplished by setting up long-term observation sites with high-quality in-situ measurements of turbulent heat, water and carbon fluxes as well as soil physical parameters in Arctic landscapes. But accurate quantification and well adapted parameterizations of turbulent fluxes in polar environments presents fundamental problems in soil-snow-ice-vegetation-atmosphere interaction studies. One of these problems is the accurate estimation of the surface or aerodynamic temperature T(0 required to force most of the bulk aerodynamic formulae currently used. Results from the Arctic-Turbulence-Experiment (ARCTEX-2006 performed on Svalbard during the winter/spring transition 2006 helped to better understand the physical exchange and transport processes of energy. The existence of an atypical temperature profile close to the surface in the Arctic spring at Svalbard could be proven to be one of the major issues hindering estimation of the appropriate surface temperature. Thus, it is essential to adjust the set-up of measurement systems carefully when applying flux-gradient methods that are commonly used to force atmosphere-ocean/land-ice models. The results of a comparison of different sensible heat-flux parameterizations with direct measurements indicate that the use of a hydrodynamic three-layer temperature-profile model achieves the best fit and reproduces the temporal variability of the surface temperature better than other approaches.

  13. Influence of climate change on the Arctic Contamination Potential

    Science.gov (United States)

    Hansen, Kaj M.; Christensen, Jesper H.; Brandt, Jørgen

    2014-05-01

    Using the Danish Eulerian Hemispheric Model (DEHM) we have calculated the Arctic Contamination Potential (ACP). ACP is defined as the sum of masses in the arctic surface compartments (soil, vegetation, snow and water) at the end of a ten year simulated period normalised either with the total mass within the model domain of with the total amount emitted into the atmosphere during the ten year simulation. In this study we use the emission normalized ACP termed eACP. We have calculated the eACP for the physical-chemical phase space spanned by compounds with log Koa between 3 and 12 and log Kaw between -4 and 3 and for each point in this phase space grid we have included a perfectly persistent compound in the model. DEHM is a 3-D atmospheric chemistry-transport model modelling the atmospheric transport of four chemical groups: a group with SOx-NOx-VOC-ozone chemistry, a group with primary particulates group, a mercury chemistry group, and finally a group with Persistent Organic Pollutants with 2-d surface compartments (soil, vegetation, ocean water and a dynamic temporal snow cover) with inter-compartmental mass exchange process parameterizations. The model domain covers the Northern Hemisphere and thus includes all important source areas for the Arctic. The spatial horizontal resolution of the model system in this work is 150km x 150km and the model includes 20 vertical levels up to approximately 15km above the surface. The model system was run with meteorology obtain from ECHAM5/MPI-OM (SRES A1B scenario) for two decades: 1990-1999 and 2090-2099. Highest potential (12%) for reaching the Arctic surface compartments for the 1990s is seen for compounds with low log Koa and low log Kaw values. These are relative water soluble compounds referred to as "swimmers". For the 2090s, the overall pattern of the ACP phase space is similar to the pattern for the 1990s. ACP is generally larger for the 2090s than for the 1990s, with a maximum of 15%.

  14. Domesticating the Arctic: A Discourse Analysis of Canada's Arctic Foreign Policy

    OpenAIRE

    Aaser, Agnes Viktoria

    2014-01-01

    This thesis investigates how the concept the Arctic is utilized in a Canadian Arctic foreign policy context today. The thesis main argument is that the Canadian government discursively represents the Arctic as a domestic space by drawing on cultural references, historical analogies, geopolitical identity and representation of danger and external threats. This argument is based on a qualitative study of key Arctic policy documents produced by the Harper government since 2009. The study is...

  15. Changes in the Arctic: Background and Issues for Congress

    Science.gov (United States)

    2010-03-30

    established the U.S. Arctic Research Commission (USARC) to promote Arctic research and recommend Arctic research policy ; • designated the National Science...Foundation (NSF) as the lead federal agency for implementing Arctic research policy ; • established the Interagency Arctic Research Policy Committee...IARPC) to develop a national Arctic research policy and a five-year plan to implement that policy, and designated the NSF representative on the IARPC

  16. Climatic and biotic extreme events moderate long-term responses of above- and belowground sub-Arctic heathland communities to climate change.

    Science.gov (United States)

    Bokhorst, Stef; Phoenix, Gareth K; Berg, Matty P; Callaghan, Terry V; Kirby-Lambert, Christopher; Bjerke, Jarle W

    2015-11-01

    Climate change impacts are not uniform across the Arctic region because interacting factors causes large variations in local ecosystem change. Extreme climatic events and population cycles of herbivores occur simultaneously against a background of gradual climate warming trends and can redirect ecosystem change along routes that are difficult to predict. Here, we present the results from sub-Arctic heath vegetation and its belowground micro-arthropod community in response to the two main drivers of vegetation damage in this region: extreme winter warming events and subsequent outbreaks of the defoliating autumnal moth caterpillar (Epirrita autumnata). Evergreen dwarf shrub biomass decreased (30%) following extreme winter warming events and again by moth caterpillar grazing. Deciduous shrubs that were previously exposed to an extreme winter warming event were not affected by the moth caterpillar grazing, while those that were not exposed to warming events (control plots) showed reduced (23%) biomass from grazing. Cryptogam cover increased irrespective of grazing or winter warming events. Micro-arthropods declined (46%) following winter warming but did not respond to changes in plant community. Extreme winter warming and caterpillar grazing suppressed the CO2 fluxes of the ecosystem. Evergreen dwarf shrubs are disadvantaged in a future sub-Arctic with more stochastic climatic and biotic events. Given that summer warming may further benefit deciduous over evergreen shrubs, event and trend climate change may both act against evergreen shrubs and the ecosystem functions they provide. This is of particular concern given that Arctic heath vegetation is typically dominated by evergreen shrubs. Other components of the vegetation showed variable responses to abiotic and biotic events, and their interaction indicates that sub-Arctic vegetation response to multiple pressures is not easy to predict from single-factor responses. Therefore, while biotic and climatic events may

  17. History of sea ice in the Arctic

    DEFF Research Database (Denmark)

    Polyak, Leonid; Alley, Richard B.; Andrews, John T.

    2010-01-01

    Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past....... This information can be provided by proxy records fromthe Arctic Ocean floor and from the surrounding coasts. Although existing records are far from complete, they indicate that sea ice became a feature of the Arctic by 47 Ma, following a pronounced decline in atmospheric pCO2 after the Paleocene–Eocene Thermal...... Optimum, and consistently covered at least part of the Arctic Ocean for no less than the last 13–14 million years. Ice was apparently most widespread during the last 2–3 million years, in accordance with Earth’s overall cooler climate. Nevertheless, episodes of considerably reduced sea ice or even...

  18. History of sea ice in the Arctic

    DEFF Research Database (Denmark)

    Polyak, Leonid; Alley, Richard B.; Andrews, John T.

    2010-01-01

    -scale) and lower-magnitude variability. The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable......Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past....... This information can be provided by proxy records fromthe Arctic Ocean floor and from the surrounding coasts. Although existing records are far from complete, they indicate that sea ice became a feature of the Arctic by 47 Ma, following a pronounced decline in atmospheric pCO2 after the Paleocene–Eocene Thermal...

  19. Arctic tipping points: governance in turbulent times.

    Science.gov (United States)

    Young, Oran R

    2012-02-01

    Interacting forces of climate change and globalization are transforming the Arctic. Triggered by a non-linear shift in sea ice, this transformation has unleashed mounting interest in opportunities to exploit the region's natural resources as well as growing concern about environmental, economic, and political issues associated with such efforts. This article addresses the implications of this transformation for governance, identifies limitations of existing arrangements, and explores changes needed to meet new demands. It advocates the development of an Arctic regime complex featuring flexibility across issues and adaptability over time along with an enhanced role for the Arctic Council both in conducting policy-relevant assessments and in promoting synergy in interactions among the elements of the emerging Arctic regime complex. The emphasis throughout is on maximizing the fit between the socioecological features of the Arctic and the character of the governance arrangements needed to steer the Arctic toward a sustainable future.

  20. Arctic whaling : proceedings of the International Symposium Arctic Whaling February 1983

    NARCIS (Netherlands)

    Jacob, H.K. s'; Snoeijing, K

    1984-01-01

    Contents: D.M. Hopkins and Louie Marincovich Jr. Whale Biogeography and the history of the Arctic Basin P.M. Kellt, J.H.W. Karas and L.D. Williams Arctic Climate: Past, Present and Future Torgny E. Vinje On the present state and the future fate of the Arctic sea ice cover P.J.H. van Bree On the biol

  1. The motives and interests of non-Arctic states on Arctic development

    OpenAIRE

    Sergey N. Grinyaev

    2016-01-01

    The article summarizes the work of the Center for Strategic Assessments and Forecasts on the study of strategy and policy of the Arctic Council observer countries. It is proposed in the number of the Arctic Council observer organizations include the Russian Geographical Society — internationally recognized and oldest scientific community, which has made a significant contribution to the development of the Arctic.

  2. Multiscale Models of Melting Arctic Sea Ice

    Science.gov (United States)

    2014-09-30

    1 Multiscale Models of Melting Arctic Sea Ice Kenneth M. Golden University of Utah, Department of Mathematics phone: (801) 581-6851...feedback has played a major role in the recent declines of the summer Arctic sea ice pack. However, understanding the evolution of melt ponds and sea...Models of Melting Arctic Sea Ice 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER

  3. Land-Cover and Land-Use Change under Changing Climate in the Eurasian Arctic

    Science.gov (United States)

    Gutman, G.

    2009-04-01

    An overview of the studies conducted in the framework of the NASA Land-Cover/Land- Use Change Program focused on the Eurasian Arctic will be presented. It includes discussion of vegetation changes under climate warming and implications to carbon cycle, changes in environmental pollution, hydrologic cycle, and impacts on society. Climate change can affect land cover in the Arctic through changes in the surface reflectivity and hydrology due to changes in snow melt timing; impacts of black carbon emitted by fires and settled on bright surfaces; changes in sea ice and the consequent change in ocean circulation affecting vegetation cover patterns indirectly; and changes in the amounts of greenhouse gases emission due to permafrost melting, especially in peatlands, as warming progresses. The Arctic Eurasia is being affected by global and regional external factors that are causing its change and the positive feedbacks to this forcing may further exaggerate the situation. If the warming trend continues it will have a tremendous impact on all aspects of land cover in the Arctic region with considerable consequences at the global scale. It will cause significant changes in the natural land cover, and perhaps even greater changes in the areas where the land cover has already been considerably modified by human activities. Major changes have already taken place in how land is used in the Arctic. In many regions, there has been a clear shift from the land use practiced by indigenous people to intensive exploitation of the land for commercial and industrial uses. Results on the climate/environment - land-cover interactions will be presented.

  4. Comparison modeling for alpine vegetation distribution in an arid area.

    Science.gov (United States)

    Zhou, Jihua; Lai, Liming; Guan, Tianyu; Cai, Wetao; Gao, Nannan; Zhang, Xiaolong; Yang, Dawen; Cong, Zhentao; Zheng, Yuanrun

    2016-07-01

    Mapping and modeling vegetation distribution are fundamental topics in vegetation ecology. With the rise of powerful new statistical techniques and GIS tools, the development of predictive vegetation distribution models has increased rapidly. However, modeling alpine vegetation with high accuracy in arid areas is still a challenge because of the complexity and heterogeneity of the environment. Here, we used a set of 70 variables from ASTER GDEM, WorldClim, and Landsat-8 OLI (land surface albedo and spectral vegetation indices) data with decision tree (DT), maximum likelihood classification (MLC), and random forest (RF) models to discriminate the eight vegetation groups and 19 vegetation formations in the upper reaches of the Heihe River Basin in the Qilian Mountains, northwest China. The combination of variables clearly discriminated vegetation groups but failed to discriminate vegetation formations. Different variable combinations performed differently in each type of model, but the most consistently important parameter in alpine vegetation modeling was elevation. The best RF model was more accurate for vegetation modeling compared with the DT and MLC models for this alpine region, with an overall accuracy of 75 % and a kappa coefficient of 0.64 verified against field point data and an overall accuracy of 65 % and a kappa of 0.52 verified against vegetation map data. The accuracy of regional vegetation modeling differed depending on the variable combinations and models, resulting in different classifications for specific vegetation groups.

  5. Long-term protection effects of national reserve to forest vegetation in 4 decades: Biodiversity change analysis of major forest types in Changbai Mountain Nature Reserve, China

    Institute of Scientific and Technical Information of China (English)

    BAI Fan; SANG WeiGuo; LI GuangQi; LIU RuiGang; CHEN LingZhi; WANG Kun

    2008-01-01

    The Changbai Mountain Nature Reserve (CNR) was established in 1960 to protect the virgin Korean pine mixed hardwood forest, a typical temperate forest of northeast China. We conducted systematic stud-ies of vascular diversity patterns on the north slope of the CNR mountainside forests (800-1700 m a.s.I.) in 1963 and 2006 respectively. The aim of this comparison is to assess the long-term effects of the protection on plant biodiversity of CNR during the interval 43 years. The research was carried out in three types of forests: mixed coniferous and broad-leaved forest (MCBF), mixed coniferous forest (MCF), and sub-alpine coniferous forest (SCF), characterized by different dominant species. The alpha diversity indicted by species richness and the Shannon-Wiener index were found different in the same elevations and forest types during the 43-year interval. The floral composition and the diversity of vascular species were generally similar along altitudinal gradients before and after the 43-year interval, but some substantial changes were evident with the altitude gradient. In the tree layers, the dominant species in 2006 were similar to those of 1963, though diversity declined with altitude. The indices in the three forest types did not differ significantly between 1963 and 2006, and these values even increased in the MCBF and MCF from 1963 to 2006. However, originally dominant species, P. koraiensis for ex-ample, tended to decline, while the proportion of broad-leaved trees increased, and the species turn-over in the succession layers trended to shift to higher altitudes. The diversity pattern of the under canopy fluctuated along the altitudinal gradient due to micro-environmental variations. Comparison of the alpha diversity in the three forests shows that the diversity of the shrub and herb layer decreased with time. During the process of survey, we also found some rare and medicinal species disappeared. Analysis indicates that the changes of the diversity pattern

  6. Long-term protection effects of national reserve to forest vegetation in 4 decades: biodiversity change analysis of major forest types in Changbai Mountain Nature Reserve, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Changbai Mountain Nature Reserve (CNR) was established in 1960 to protect the virgin Korean pine mixed hardwood forest, a typical temperate forest of northeast China. We conducted systematic stud- ies of vascular diversity patterns on the north slope of the CNR mountainside forests (800-1700 m a.s.l.) in 1963 and 2006 respectively. The aim of this comparison is to assess the long-term effects of the protection on plant biodiversity of CNR during the interval 43 years. The research was carried out in three types of forests: mixed coniferous and broad-leaved forest (MCBF), mixed coniferous forest (MCF), and sub-alpine coniferous forest (SCF), characterized by different dominant species. The alpha diversity indicted by species richness and the Shannon-Wiener index were found different in the same elevations and forest types during the 43-year interval. The floral composition and the diversity of vascular species were generally similar along altitudinal gradients before and after the 43-year interval, but some substantial changes were evident with the altitude gradient. In the tree layers, the dominant species in 2006 were similar to those of 1963, though diversity declined with altitude. The indices in the three forest types did not differ significantly between 1963 and 2006, and these values even increased in the MCBF and MCF from 1963 to 2006. However, originally dominant species, P. koraiensis for ex- ample, tended to decline, while the proportion of broad-leaved trees increased, and the species turn- over in the succession layers trended to shift to higher altitudes. The diversity pattern of the under canopy fluctuated along the altitudinal gradient due to micro-environmental variations. Comparison of the alpha diversity in the three forests shows that the diversity of the shrub and herb layer decreased with time. During the process of survey, we also found some rare and medicinal species disappeared. Analysis indicates that the changes of the diversity

  7. Long-term protection effects of National Reserve to forest vegetation in 4 decades: biodiversity change analysis of major forest types in Changbai Mountain Nature Reserve, China.

    Science.gov (United States)

    Bai, Fan; Sang, WeiGuo; Li, GuangQi; Liu, RuiGang; Chen, LingZhi; Wang, Kun

    2008-10-01

    The Changbai Mountain Nature Reserve (CNR) was established in 1960 to protect the virgin Korean pine mixed hardwood forest, a typical temperate forest of northeast China. We conducted systematic studies of vascular diversity patterns on the north slope of the CNR mountainside forests (800-1700 m a.s.l.) in 1963 and 2006 respectively. The aim of this comparison is to assess the long-term effects of the protection on plant biodiversity of CNR during the interval 43 years. The research was carried out in three types of forests: mixed coniferous and broad-leaved forest (MCBF), mixed coniferous forest (MCF), and sub-alpine coniferous forest (SCF), characterized by different dominant species. The alpha diversity indicted by species richness and the Shannon-Wiener index were found different in the same elevations and forest types during the 43-year interval. The floral composition and the diversity of vascular species were generally similar along altitudinal gradients before and after the 43-year interval, but some substantial changes were evident with the altitude gradient. In the tree layers, the dominant species in 2006 were similar to those of 1963, though diversity declined with altitude. The indices in the three forest types did not differ significantly between 1963 and 2006, and these values even increased in the MCBF and MCF from 1963 to 2006. However, originally dominant species, P. koraiensis for example, tended to decline, while the proportion of broad-leaved trees increased, and the species turnover in the succession layers trended to shift to higher altitudes. The diversity pattern of the under canopy fluctuated along the altitudinal gradient due to micro-environmental variations. Comparison of the alpha diversity in the three forests shows that the diversity of the shrub and herb layer decreased with time. During the process of survey, we also found some rare and medicinal species disappeared. Analysis indicates that the changes of the diversity pattern in

  8. Arctic tides from GPS on sea ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing...... of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic. The GPS measurements are compared with the Arctic tidal model AOTIM-5, which assimilates tide...

  9. Plate tectonic history of the Arctic

    Science.gov (United States)

    Burke, K.

    1984-01-01

    Tectonic development of the Arctic Ocean is outlined, and geological maps are provided for the Arctic during the mid-Cenozoic, later Cretaceous, late Jurassic, early Cretaceous, early Jurassic and late Devonian. It is concluded that Arctic basin history is moulded by the events of the following intervals: (1) continental collision and immediately subsequent rifting and ocean formation in the Devonian, and continental rifting ocean formation, rapid rotation of microcontinents, and another episode of collision in the latest Jurassic and Cretaceous. It is noted that Cenozoic Arctic basin formation is a smaller scale event superimposed on the late Mesozoic ocean basin.

  10. Rossby Waves in the Arctic Ocean

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Schmith, Torben

    The Arctic Ocean has a characteristic stable stratification with fresh and cold water occupying the upper few hundred meters and the warm and more saline Atlantic waters underneath. These water masses are separated by the cold halocline. The stability of the cold halocline regulates the upward...... directed turbulent heat flux from the Atlantic water to the Arctic water. This heat flux is a part of the arctic energy budget and is important for large scale sea ice formation and melting. Due to the strong vertical stratification combined with its almost circular boundary, the Arctic Ocean supports...

  11. Record-low primary productivity and high plant damage in the Nordic Arctic Region in 2012 caused by multiple weather events and pest outbreaks

    Science.gov (United States)

    Bjerke, Jarle W.; Rune Karlsen, Stein; Arild Høgda, Kjell; Malnes, Eirik; Jepsen, Jane U.; Lovibond, Sarah; Vikhamar-Schuler, Dagrun; Tømmervik, Hans

    2014-08-01

    The release of cold temperature constraints on photosynthesis has led to increased productivity (greening) in significant parts (32-39%) of the Arctic, but much of the Arctic shows stable (57-64%) or reduced productivity (browning, factors dampening the greening effect of more maritime regions have remained elusive. Here we show how multiple anomalous weather events severely affected the terrestrial productivity during one water year (October 2011-September 2012) in a maritime region north of the Arctic Circle, the Nordic Arctic Region, and contributed to the lowest mean vegetation greenness (normalized difference vegetation index) recorded this century. Procedures for field data sampling were designed during or shortly after the events in order to assess both the variability in effects and the maximum effects of the stressors. Outbreaks of insect and fungal pests also contributed to low greenness. Vegetation greenness in 2012 was 6.8% lower than the 2000-11 average and 58% lower in the worst affected areas that were under multiple stressors. These results indicate the importance of events (some being mostly neglected in climate change effect studies and monitoring) for primary productivity in a high-latitude maritime region, and highlight the importance of monitoring plant damage in the field and including frequencies of stress events in models of carbon economy and ecosystem change in the Arctic. Fourteen weather events and anomalies and 32 hypothesized impacts on plant productivity are summarized as an aid for directing future research.

  12. Aerosols indirectly warm the Arctic

    Directory of Open Access Journals (Sweden)

    T. Mauritsen

    2010-07-01

    Full Text Available On average, airborne aerosol particles cool the Earth's surface directly by absorbing and scattering sunlight and indirectly by influencing cloud reflectivity, life time, thickness or extent. Here we show that over the central Arctic Ocean, where there is frequently a lack of aerosol particles upon which clouds may form, a small increase in aerosol loading may enhance cloudiness thereby likely causing a climatologically significant warming at the ice-covered Arctic surface. Under these low concentration conditions cloud droplets grow to drizzle sizes and fall, even in the absence of collisions and coalescence, thereby diminishing cloud water. Evidence from a case study suggests that interactions between aerosol, clouds and precipitation could be responsible for attaining the observed low aerosol concentrations.

  13. Stories from the Arctic field

    Science.gov (United States)

    Cain, Michelle

    2016-04-01

    I will discuss my experience co-ordinating a range of communication activities for a multi-university research programme called Methane in the Arctic: Measurements and Modelling. The project included ground- and aircraft-based fieldwork in the European Arctic, as well as computer modelling. Our communication activities included: our own field blog (www.arcticmethane.wordpress.com), which was syndicated to the Scientific American Expeditions blog; writing articles for other blogs with a wider audience than our own; use of twitter; and podcasting our field work. The grand finale to our communications work was a live event at a science festival, in which we took the audience along with us on a recreated research flight, complete with a life-size mock up of a section of our research aircraft. I will discuss my experiences of these forms of communication, and give an evaluation of their successes and failures.

  14. Extrapolating future Arctic ozone losses

    Directory of Open Access Journals (Sweden)

    B. M. Knudsen

    2004-06-01

    Full Text Available Future increases in the concentration of greenhouse gases and water vapour are likely to cool the stratosphere further and to increase the amount of polar stratospheric clouds (PSCs. Future Arctic PSC areas have been extrapolated using the highly significant trends in the temperature record from 1958–2001. Using a tight correlation between PSC area and the total vortex ozone depletion and taking the decreasing amounts of ozone depleting substances into account we make empirical estimates of future ozone. The result is that Arctic ozone losses increase until 2010–2020 and only decrease slightly up to 2030. This approach is an alternative method of prediction to that based on the complex coupled chemistry-climate models (CCMs.

  15. Global Warming and the Arctic in 3D: A Virtual Globe for Outreach

    Science.gov (United States)

    Manley, W. F.

    2006-12-01

    Virtual Globes provide a new way to capture and inform the public's interest in environmental change. As an example, a recent Google Earth presentation conveyed 'key findings' from the Arctic Climate Impact Assessment (ACIA, 2004) to middle school students during the 2006 INSTAAR/NSIDC Open House at the University of Colorado. The 20-minute demonstration to 180 eighth graders began with an introduction and a view of the Arctic from space, zooming into the North American Arctic, then to a placemark for the first key finding, 'Arctic climate is now warming rapidly and much larger changes are projected'. An embedded link then opened a custom web page, with brief explanatory text, along with an ACIA graphic illustrating the rise in Arctic temperature, global CO2 concentrations, and carbon emissions for the last millennium. The demo continued with an interactive tour of other key findings (Reduced Sea Ice, Changes for Animals, Melting Glaciers, Coastal Erosion, Changes in Vegetation, Melting Permafrost, and others). Each placemark was located somewhat arbitrarily (which may be a concern for some audiences), but the points represented the messages in a geographic sense and enabled a smooth visual tour of the northern latitudes. Each placemark was linked to custom web pages with photos and concise take-home messages. The demo ended with navigation to Colorado, then Boulder, then the middle school that the students attended, all the while speaking to implications as they live their lives locally. The demo piqued the students' curiosity, and in this way better conveyed important messages about the Arctic and climate change. The use of geospatial visualizations for outreach and education appears to be in its infancy, with much potential.

  16. Long photoperiods sustain high pH in Arctic kelp forests.

    Science.gov (United States)

    Krause-Jensen, Dorte; Marbà, Núria; Sanz-Martin, Marina; Hendriks, Iris E; Thyrring, Jakob; Carstensen, Jacob; Sejr, Mikael Kristian; Duarte, Carlos M

    2016-12-01

    Concern on the impacts of ocean acidification on calcifiers, such as bivalves, sea urchins, and foraminifers, has led to efforts to understand the controls on pH in their habitats, which include kelp forests and seagrass meadows. The metabolism of these habitats can lead to diel fluctuation in pH with increases during the day and declines at night, suggesting no net effect on pH at time scales longer than daily. We examined the capacity of subarctic and Arctic kelps to up-regulate pH in situ and experimentally tested the role of photoperiod in determining the capacity of Arctic macrophytes to up-regulate pH. Field observations at photoperiods of 15 and 24 hours in Greenland combined with experimental manipulations of photoperiod show that photoperiods longer than 21 hours, characteristic of Arctic summers, are conducive to sustained up-regulation of pH by kelp photosynthesis. We report a gradual increase in pH of 0.15 units and a parallel decline in pCO2 of 100 parts per million over a 10-day period in an Arctic kelp forest over midsummer, with ample scope for continued pH increase during the months of continuous daylight. Experimental increase in CO2 concentration further stimulated the capacity of macrophytes to deplete CO2 and increase pH. We conclude that long photoperiods in Arctic summers support sustained up-regulation of pH in kelp forests, with potential benefits for calcifiers, and propose that this mechanism may increase with the projected expansion of Arctic vegetation in response to warming and loss of sea ice.

  17. Building Materials in Arctic Climate

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    2005-01-01

    Building in the artic requires special attention on the appropriateness of building materials. The harsh climate makes execution difficult and sets unusual requirements for the pure material properties. In addition, there is a lack of choice of good, natural building materials in the arctic....... This results in high transport costs. The building materials situation in Greenland may potentially be improved by intensifying the reuse of building materials or by promoting the local production of building materials....

  18. Can Canada Avoid Arctic Militarization?

    Science.gov (United States)

    2014-05-20

    Passage is considered an international strait because it joins two high-seas areas used for international navigations.28 Geography is the key to the...2014). 42Roger Howard, 54. 43Sian Griffith, “US-Canada Arctic Border Dispute Key to Maritime Riches,” BBC News , August 2, 2010, http://www.bbc.com...Chilingarov, Deputy Chairman of the Russian Duma and a famous Polar scientist, directed a submarine expedition to the North Pole and planted a Russian flag

  19. Arctic bioremediation -- A case study

    Energy Technology Data Exchange (ETDEWEB)

    Smallbeck, D.R.; Ramert, P.C. (Harding Lawson Associates, Novato, CA (United States)); Liddell, B.V.

    1994-05-01

    This paper discusses the use of bioremediation as an effective method to clean up diesel-range hydrocarbon spills in northern latitudes. The results of a laboratory study of microbial degradation of hydrocarbons under simulated arctic conditions showed that bioremediation can be effective in cold climates and led to the implementation of a large-scale field program. The results of 3 years of field testing have led to a significant reduction in diesel-range hydrocarbon concentrations in the contaminated area.

  20. The Arctic: The Physical Environment

    Science.gov (United States)

    2010-09-01

    canadienne est de planifier , de mettre sur pied et de maintenir des forces maritimes polyvalentes, souples et aptes au combat pour atteindre les objectifs...implications could be wide ranging. As one scholar notes: “The net effect [of climate change] is an overall warming process that is now beginning a...scientific research and study. Arctic nations have also begun the process of extending their exclusive economic rights under the 1982 United Nations

  1. The Paleocene Eocene carbon isotope excursion in higher plant organic matter: Differential fractionation of angiosperms and conifers in the Arctic

    Science.gov (United States)

    Schouten, Stefan; Woltering, Martijn; Rijpstra, W. Irene C.; Sluijs, Appy; Brinkhuis, Henk; Sinninghe Damsté, Jaap S.

    2007-06-01

    A study of upper Paleocene-lower Eocene (P-E) sediments deposited on the Lomonosov Ridge in the central Arctic Ocean reveals relatively high abundances of terrestrial biomarkers. These include dehydroabietane and simonellite derived from conifers (gymnosperms) and a tetra-aromatic triterpenoid derived from angiosperms. The relative percentage of the angiosperm biomarker of the summed angiosperm + conifer biomarkers was increased at the end of the Paleocene-Eocene thermal maximum (PETM), different when observed with pollen counts which showed a relative decrease in angiosperm pollen. Stable carbon isotopic analysis of these biomarkers shows that the negative carbon isotope excursion (CIE) during the PETM amounts to 3‰ for both conifer biomarkers, dehydroabietane and simonellite, comparable to the magnitude of the CIE inferred from marine carbonates, but significantly lower than the 4.5‰ of the terrestrial C 29n-alkane [M. Pagani, N. Pedentchouk, M. Huber, A. Sluijs, S. Schouten, H. Brinkhuis, J.S. Sinninghe Damsté, G.R. Dickens, and the IODP Expedition 302 Expedition Scientists (2006), Arctic's hydrology during global warming at the Paleocene-Eocene thermal maximum. Nature, 442, 671-675.], which is a compound sourced by both conifers and angiosperms. Conspicuously, the angiosperm-sourced aromatic triterpane shows a much larger CIE of 6‰ and suggests that angiosperms increased in their carbon isotopic fractionation during the PETM. Our results thus indicate that the 4.5‰ C 29n-alkane CIE reported previously represents the average CIE of conifers and angiosperms at this site and suggest that the large and variable CIE observed in terrestrial records may be partly explained by the variable contributions of conifers and angiosperms. The differential response in isotopic fractionation of angiosperms and conifers points to different physiological responses of these vegetation types to the rise in temperature, humidity, and greenhouse gases during the PETM.

  2. The Pliocene High Arctic terrestrial palaeoenvironmental record and the development of the western Canadian Arctic coastal plain

    Science.gov (United States)

    Rybczynski, N.; Braschi, L.; Gosse, J. C.; Kennedy, C.; Fraser, D.; Lakeman, T.

    2013-12-01

    The Pliocene fossil record of the High Arctic is represented by a collection of sites that occur across the Canadian Arctic Archipelago (CAA), with deposits in the west comprising a 1200 km-long dissected clastic wedge (Beaufort Formation) and those in the east represented by high terrace gravel deposits. Fossil material from these sites is often very well preserved and provides evidence of a boreal-type forest. In the eastern Arctic our research sites includes the Fyles Leaf Bed (FLB) and the Beaver Pond (BP) sites, on west central Ellesmere Island. These are about 10 km apart and preserve evidence of forest and peatlands. The BP fossil site preserves the remains of fossil vertebrates including fish, frog, horse, beaver, deerlet, and black bear, consistent with a boreal type forest habitat. The FLB site has recently yielded the first fossil evidence for a High Arctic camel, identified with the help of collagen fingerprinting from a fragmentary limb bone (tibia). Although modern camels live in open habitats, biogeographic and comparative dental evidence, in combination, suggest that the North American Arctic camels were browsers, and therefore forest-dwelling. Paleoenvironmental reconstruction of the Ellesmere sites has yielded a Mean Annual Temperature of between 14 to 22 degrees Celsius warmer than today. Minimum cosmogenic nuclide burial ages of 3.4 and 3.8 Ma obtained for the BP and FLB sites, respectively, are consistent with vertebrate and floral biostratigraphic evidence. The Beaufort Formation, located in the Western CAA, was formed by a regional northwesterly flowing braided fluvial system. The Beaufort Formation appears to have filled at least the western portions of the 100 km-wide channels that currently separate the islands of the CAA. Intervals of Pliocene continental-shelf progradation are recorded in the lower Iperk Formation, which is situated offshore and includes complex sigmoid-oblique clinoforms indicative of high-energy, coarse

  3. Technology Drives Vegetable Industry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Arobot for vegetable planting is able to examine growing conditions, detect disease of the vegetables and pick up the ripe ones through identifying the color; a tomato tree is able to produce up to 3,000kgs of tomatoes; sweet potatoes are growing in the air; fish and vegeta-bles are living together harmoniously...Viewing these, you may doubt that you were in a fancy world.Actually, you are here at the 12th China (Shouguang) International Vegetable Sci-tech Fair.

  4. Selection of Hyperspectral Narrowbands (HNBs) and Composition of Hyperspectral Twoband Vegetation Indices (HVIs) for Biophysical Characterization and Discrimination of Crop Types Using Field Reflectance and Hyperion-EO-1 Data

    Science.gov (United States)

    Thenkabail, Prasad S.; Mariotto, Isabella; Gumma, Murali Krishna; Middleton, Elizabeth M.; Landis, David R.; Huemmrich, K. Fred

    2013-01-01

    The overarching goal of this study was to establish optimal hyperspectral vegetation indices (HVIs) and hyperspectral narrowbands (HNBs) that best characterize, classify, model, and map the world's main agricultural crops. The primary objectives were: (1) crop biophysical modeling through HNBs and HVIs, (2) accuracy assessment of crop type discrimination using Wilks' Lambda through a discriminant model, and (3) meta-analysis to select optimal HNBs and HVIs for applications related to agriculture. The study was conducted using two Earth Observing One (EO-1) Hyperion scenes and other surface hyperspectral data for the eight leading worldwide crops (wheat, corn, rice, barley, soybeans, pulses, cotton, and alfalfa) that occupy approx. 70% of all cropland areas globally. This study integrated data collected from multiple study areas in various agroecosystems of Africa, the Middle East, Central Asia, and India. Data were collected for the eight crop types in six distinct growth stages. These included (a) field spectroradiometer measurements (350-2500 nm) sampled at 1-nm discrete bandwidths, and (b) field biophysical variables (e.g., biomass, leaf area index) acquired to correspond with spectroradiometer measurements. The eight crops were described and classified using approx. 20 HNBs. The accuracy of classifying these 8 crops using HNBs was around 95%, which was approx. 25% better than the multi-spectral results possible from Landsat-7's Enhanced Thematic Mapper+ or EO-1's Advanced Land Imager. Further, based on this research and meta-analysis involving over 100 papers, the study established 33 optimal HNBs and an equal number of specific two-band normalized difference HVIs to best model and study specific biophysical and biochemical quantities of major agricultural crops of the world. Redundant bands identified in this study will help overcome the Hughes Phenomenon (or "the curse of high dimensionality") in hyperspectral data for a particular application (e

  5. Dynamical vegetation-atmosphere modelling of the boreal zone

    Science.gov (United States)

    Tang, Hui; Stordal, Frode; Berntsen, Terje K.; Bryn, Anders

    2016-04-01

    Vegetation interacts with climate on seasonal to inter-annual time scales through albedo, roughness, evapotranspiration, CO2 sequestration and by influencing snow accumulation and ablation. The Scandinavian mountains and high latitudes is a hot spot for land-atmosphere feedback, as the future's increased winter minimum temperature supports a boreal tree line advance, lowering the surface albedo. The northern ecosystem is dominated by mires, boreal forests and alpine heaths, in addition to agricultural land. Model studies have shown that vegetation-climate feedbacks are strong enough to lead to regime shifts in vegetation and local climate in boreal regions. Biogeophysical factors, such as albedo, the Bowen ratio, and surface roughness, are all involved in these feedbacks, and they are also altered by land use change such as reforestation. For calculations of the dynamical coupling between the atmosphere and the vegetation we have used the Earth System Model NorESM, which includes several advanced features in its land surface model (CLM4.5), such as the inclusion of the radiative forcing due to black carbon and dust deposit onto snow, improved representation of fire, permafrost and its hydrological impact, a new snow cover fraction parameterization reflecting the hysteresis in fractional snow cover for a given snow depth between accumulation and melt phases, as well as dynamic vegetation coupled with carbon-nitrogen cycles. These new features improve the representation of surface albedo feedback in Arctic. We have performed experiments with coupled as well fixed ocean for the current as a quadrupled atmospheric CO2 situation. This model configuration is used to study changes in vegetation in a high end radiative forcing case. It is contrasted with an experiment where vegetation dynamics is neglected. Changes in the features of the vegetation along with surface fluxes, albedo and atmospheric temperatures are analysed, with main emphasis on the boreal zone. In

  6. Investigating vegetation-climate feedbacks during the early Eocene

    Directory of Open Access Journals (Sweden)

    C. A. Loptson

    2013-08-01

    Full Text Available Evidence suggests that the early Eocene was a time of extreme global warmth, extending to the high latitudes. However, there are discrepancies between the results of many previous modelling studies and the proxy data at high latitudes, with models struggling to simulate the shallow temperature gradients of this time period to the same extent as the proxies indicate. Vegetation-climate feedbacks play an important role in the present day, but are often neglected in paleoclimate modelling studies and this may be a contributing factor to resolving the model-data discrepancy. Here we investigate these vegetation-climate feedbacks by carrying out simulations of the early Eocene climate at 2 × and 4 × pre-industrial atmospheric CO2 with fixed vegetation (homogeneous shrubs everywhere and dynamic vegetation. The results show that the simulations with dynamic vegetation are warmer in the global annual mean than the simulations with fixed shrubs by 0.9 °C at 2 × and 1.8 °C at 4 ×. In addition, the warming when CO2 is doubled from 2 × to 4 × is 1 °C higher (in the global annual mean with dynamic vegetation than with fixed shrubs. This corresponds to an increase in climate sensitivity of 26%. This difference in warming is enhanced at high latitudes, with temperatures increasing by over 50% in some regions of Antarctica. In the Arctic, ice-albedo feedbacks are responsible for the majority of this warming. On a global scale, energy balance analysis shows that the enhanced warming with dynamic vegetation is mainly associated with an increase in atmospheric water vapour but changes in clouds also contribute to the temperature increase. It is likely that changes in surface albedo due to changes in vegetation cover resulted in an initial warming which triggered these water vapour feedbacks. In conclusion, dynamic vegetation goes some way to resolving the discrepancy, but our modelled temperatures cannot reach the same warmth as the data suggests in the

  7. International Regulation of Central Arctic Ocean Fisheries

    NARCIS (Netherlands)

    Molenaar, E.J.

    2016-01-01

    Due in particular to the impacts of climate change, the adequacy of the international regulation of Central Arctic Ocean fisheries has come under increasing scrutiny in recent years. As shown in this article, however, international regulation of Central Arctic Ocean fisheries is by no means entirely

  8. Linking Arctic amplification and local feedbacks

    Science.gov (United States)

    Balcerak, Ernie

    2011-11-01

    Climate simulations show that as the Earth warms, the Arctic warms more than the average global warming. However, models differ on how much more the Arctic warms, and although scientists have proposed a variety of mechanisms to explain the Arctic warming amplification, there is no consensus on the main reasons for it. To shed light on this issue, Hwang et al. investigated the relationship between Arctic amplification and poleward energy transport and local Arctic feedbacks, such as changes in cloud cover or ice loss, across a group of models. The researchers noted that differences in atmospheric energy transport did not explain the ranges of polar amplification; rather, models with more amplification showed less energy transport into high latitudes. The authors found that decreasing energy transport is due to a coupled relationship between Arctic amplification and energy transport: Arctic amplification reduces the equator-to-pole temperature gradient, which strongly decreases energy transport. They suggest that this coupled relationship should be taken into account in studies of Arctic amplification. (Geophysical Research Letters, doi:10.1029/2011GL048546, 2011)

  9. Arctic freshwater export: Status, mechanisms, and prospects

    NARCIS (Netherlands)

    Haine, T.W.N.; Curry, B.; Gerdes, R.; Hansen, E.; Karcher, M.; Lee, C.; Rudels, B.; Spreen, G.; de Steur, L.; Stewart, K.D.; Woodgate, R.

    2015-01-01

    Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980–2000, with an extra ˜ 5000 km3 — about 25% — being stored. The sources of freshwater to the Arctic from precipitation and runo

  10. Benefit-sharing arrangements in the Arctic

    NARCIS (Netherlands)

    Tysyachnyouk, M.

    2016-01-01

    Can the interests of both the extractive industries and Indigenous communities in the Arctic be balanced through the implementation of benefit-sharing practices in the places of resource extraction? Most transnational corporations
    in the Arctic oil and gas sector have declared their commitment t

  11. Pacific Northwest Laboratory Alaska (ARCTIC) research program

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, W.C.; Eberhardt, L.E.

    1980-03-01

    The current program continues studies of arctic ecosystems begun in 1959 as part of the Cape Thompson Program. Specific ecosystem aspects include studies of the ecology of arctic and red foxes, small mammel and bird population studies, lichen studies, and radiation ecology studies. (ACR)

  12. Traditional Ecological Knowledge in Arctic EIA's

    DEFF Research Database (Denmark)

    Egede, Parnuna Petrina; Hansen, Anne Merrild

    2017-01-01

    The search for new oil and mineral reserves in the Arctic is increasing. This has called for both local and international concerns and opposition to the activities based on environmental apprehensions. Environmental Impact Assessments (EIA’s) have been implemented in legislations by the Arctic...

  13. Arctic Shrub Growth Response to Climate Variation and Infrastructure Development on the North Slope of Alaska

    Science.gov (United States)

    Ackerman, D.; Finlay, J. C.; Griffin, D.

    2015-12-01

    Woody shrub growth in the arctic tundra is increasing on a circumpolar scale. Shrub expansion alters land-atmosphere carbon fluxes, nutrient cycling, and habitat structure. Despite these ecosystem effects, the drivers of shrub expansion have not been precisely established at the landscape scale. This project examined two proposed anthropogenic drivers: global climate change and local infrastructure development, a press disturbance that generates high levels of dust deposition. Effects of global change were studied using dendrochronology to establish a relationship between climate and annual growth in Betula and Salix shrubs growing in the Alaskan low Arctic. To understand the spatial heterogeneity of shrub expansion, this analysis was replicated in shrub populations across levels of landscape properties including soil moisture and substrate age. Effects of dust deposition on normalized difference vegetation index (NDVI) and photosynthetic rate were measured on transects up to 625 meters from the Dalton Highway. Dust deposition rates decreased exponentially with distance from road, matching previous models of road dust deposition. NDVI tracked deposition rates closely, but photosynthetic rates were not strongly affected by deposition. These results suggest that dust deposition may locally bias remote sensing measurements such as NDVI, without altering internal physiological processes such as photosynthesis in arctic shrubs. Distinguishing between the effects of landscape properties, climate, and disturbance will improve our predictions of the biogeochemical feedbacks of arctic shrub expansion, with potential application in climate change modeling.

  14. 78 FR 12033 - Programs and Research Projects Affecting the Arctic

    Science.gov (United States)

    2013-02-21

    ... From the Federal Register Online via the Government Publishing Office ] ARCTIC RESEARCH COMMISSION Programs and Research Projects Affecting the Arctic Notice is hereby given that the U.S. Arctic Research...) Commissioners and staff reports (4) Discussion and presentations concerning Arctic research activities The...

  15. Establishing Shared Knowledge about Globalization in Asia and the Arctic

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Graczyk, Piotr

    2016-01-01

    We discuss the role of knowledge in relations between Arctic communities and Asia (the Arctic Council observer states: China, India, Japan, Singapore, South Korea). We argue that mutual and shared knowledge between Arctic communities and Asia is necessary for local benefits and comprehensively...... sustainable development for Arctic communities under globalization....

  16. Marine Transportation Implications of the Last Arctic Sea Ice Refuge

    Science.gov (United States)

    Brigham, L. W.

    2010-12-01

    Marine access is increasing throughout the Arctic Ocean and the 'Last Arctic Sea Ice Refuge' may have implications for governance and marine use in the region. Arctic marine transportation is increasing due to natural resource developemnt, increasing Arctic marine tourism, expanded Arctic marine research, and a general linkage of the Arctic to the gloabl economy. The Arctic Council recognized these changes with the release of the Arctic Marine Shipping Assessment of 2009. This key study (AMSA)can be viewed as a baseline assessment (using the 2004 AMSA database), a strategic guide for a host of stakeholders and actors, and as a policy document of the Arctic Council. The outcomes of AMSA of direct relevance to the Ice Refuge are within AMSA's 17 recommendations provided under three themes: Enhancing Arctic Marine Safety, Protecting Arctic People and the Environment, and Building the Arctic Marine Infrastructure. Selected recommendations of importance to the Ice Refuge include: a mandatory polar navigation code; identifying areas of heightened ecological and cultural significance; potential designation of special Arctic marine areas; enhancing the tracking and monitoring of Arctic marine traffic; improving circumpolar environmental response capacity; developing an Arctic search and rescue agreement; and, assessing the effects of marine transportation on marine mammals. A review will be made of the AMSA outcomes and how they can influence the governance, marine use, and future protection of this unique Arctic marine environment.

  17. Large increases in Arctic biogenic volatile emissions are a direct effect of warming

    Science.gov (United States)

    Kramshøj, Magnus; Vedel-Petersen, Ida; Schollert, Michelle; Rinnan, Åsmund; Nymand, Josephine; Ro-Poulsen, Helge; Rinnan, Riikka

    2016-05-01

    Biogenic volatile organic compounds are reactive gases that can contribute to atmospheric aerosol formation. Their emission from vegetation is dependent on temperature and light availability. Increasing temperature, changing cloud cover and shifting composition of vegetation communities can be expected to affect emissions in the Arctic, where the ongoing climate changes are particularly severe. Here we present biogenic volatile organic compound emission data from Arctic tundra exposed to six years of experimental warming or reduced sunlight treatment in a randomized block design. By separately assessing the emission response of the whole ecosystem, plant shoots and soil in four measurements covering the growing season, we have identified that warming increased the emissions directly rather than via a change in the plant biomass and species composition. Warming caused a 260% increase in total emission rate for the ecosystem and a 90% increase in emission rates for plants, while having no effect on soil emissions. Compared to the control, reduced sunlight decreased emissions by 69% for the ecosystem, 61-65% for plants and 78% for soil. The detected strong emission response is considerably higher than observed at more southern latitudes, emphasizing the high temperature sensitivity of ecosystem processes in the changing Arctic.

  18. Russian Arctic warming and ‘greening’ are closely tracked by tundra shrub willows

    Science.gov (United States)

    Forbes, B. C.; Macias Fauria, M.; Zetterberg, P.

    2009-12-01

    Growth in arctic vegetation is generally expected to increase under a warming climate, particularly among deciduous shrubs. We analyzed annual ring growth for an abundant and nearly circumpolar erect willow (Salix lanata L.) from the coastal zone of the northwest Russian Arctic (Nenets Autonomous Okrug). The resulting chronology is strongly related to summer temperature for the period 1942-2005. Remarkably high correlations occur at long distances (>1600 km) across the tundra and taiga zones of West Siberia and Eastern Europe. We also found a clear relationship with photosynthetic activity for upland vegetation at a regional scale for the period 1981-2005, confirming a parallel ‘greening’ trend reported for similarly warming North American portions of the tundra biome. The standardized growth curve suggests a significant increase in shrub willow growth over the last six decades. These findings are in line with field and remote sensing studies that have assigned a strong shrub component to the reported greening signal since the early 1980s. Furthermore, the growth trend agrees with qualitative observations by nomadic Nenets reindeer herders of recent increases in willow size in the region. The quality of the chronology as a climate proxy is exceptional. Given its wide geographic distribution and the ready preser