Abstract:
The Dry Valleys of Victoria Land, Antarctica, contain naturally simple ecosystems operating under extreme climatic conditions. Nutrients are limited and are thought to come from external sources from more productive parts of the landscape or from other ecosystems entirely, such as the lakes occurring in the valleys. A ‘legacy’ model suggests the origin of present day soil organic matter to be ... material laid down in ancient lake beds rather than aeolian dispersal from modern aquatic environments, as previously thought. This does not appear to hold true for smaller dry valleys and instead a ‘subsidy’ model was investigated by testing several hypotheses with a combination of: a survey of the physical and biological characteristics of the eight key landscape elements identified in the valley, experimentally measuring the benefit of wind-blown subsidies to terrestrial microbial populations and the nature of the beneficial component of the subsidies. In each of the landscapes, the soil respiration, terrestrial photosynthesis (moss colonies and cyanobacterial mats on the soil), terrestrial nitrogen fixation, approximate area covered by communities undertaking carbon and nitrogen fixation and the transfer of organic material between aquatic and terrestrial environments was quantified. The results of these measurements will be a carbon and nitrogen budget for terrestrial communities in the valley system. The parameters and landscape scale resource budgets were tested by comparing the conditions in the Garwood Valley with those in the western Wright Valley, which is characterised by an entirely internal drainage system (the Onyx River flowing into Lake Vanda), a much less productive lake that occupies a much smaller areal proportion of the total valley floor, and a climate more influenced by the extremes of arid katabatic winds. Studies were in the 04/05 and 05/06 seasons in the Garwood Valley (Lake Colleen and Buddha Lake) and the Wright Valley (Lake Vanda).
Quality
Building upon a methodology pioneered by Sachs et al. (2003), a Gross Domestic Product (GDP) value (US$, 2000, purchase power parity adjusted (PPP)) is estimated for each grid cell. The process begins by determining the contribution of each subnational unit to national GDP using data of varied origin. The ratio of the subnational production estimate to the national GDP is the contribution ratio. ... To ensure uniformity, these contribution ratios are utilized with published World Bank estimates of GDP. Once a standardized value of subnational GDP has been calculated, this value is further subdivided by the total population within the subnational unit as determined using Gridded Population of the World, Version 3 (GPWv3) data. This subnational, per-person GDP value is multiplied by the population density per grid cell to estimate the GDP value on a per grid cell basis.
Regional loss rates were derived from the Emergency Events Database (EM-DAT) records, providing estimates of the hazard's impact. Combining the impact data with the frequency and distribution data of the Global Volcano Hazard Frequency and Distribution dataset and the baseline productivity data provided by the spatially allocated GDP estimates resulted in crude estimates of the GDP at risk. In turn, these estimates are transformed into proportions of the original GDP estimates of the grid cells on a per grid cell basis. In order to more accurately reflect the confidence surrounding the proportionalities, they are further classified into deciles, 10 classes of approximately an equal number of grid cells.
Note that areas of &No Data& are not necessarily without risk from hazards, but may be an artifact of a mask that excluded from analysis those areas characterized by both a population density less than 5 persons per square kilometer and a lack of significant agriculture.
Access Constraints
None
Use Constraints
The Trustees of Columbia University in the City of New York, Center for Hazards and Risk Research (CHRR), and International Bank for Reconstruction and ... Development/The World Bank hold the copyright of this dataset. Users are prohibited from any commercial, resale, or redistribution without explicit written permission from CHRR, CIESIN, and The World Bank. Users should acknowledge CHRR, CIESIN, and The World Bank as the source used in the creation of any reports, publications, new datasets, derived products, or services resulting from the use of this dataset. CHRR, CIESIN, and The World Bank request reprints of any publications and notification of any redistribution efforts.
Center for Hazards and Risk Research (CHRR)/Columbia University, and Center for International Earth Science Information Network (CIESIN)/Columbia University (2005), Global Global Volcano Hazard Frequency and Distribution, Center for Hazards and Risk Research (CHRR)/Columbia University, Palisades, NY, http://sedac.ciesin.columbia.edu/data/set/ndh-volcano-hazard-freque...
Center for Hazards and Risk Research (CHRR)/Columbia University, Center for International Earth Science Information Network (CIESIN)/Columbia University, and International Bank for Reconstruction and Development/The World Bank (2005), Global Volcano Mortality Risks and Distribution, Center for Hazards and Risk Research (CHRR)/Columbia University, Palisades, NY, http://sedac.ciesin.columbia.edu/data/set/ndh-volcano-mortality-ris...
Center for Hazards and Risk Research (CHRR)/Columbia University, Center for International Earth Science Information Network (CIESIN)/Columbia University, and International Bank for Reconstruction and Development/The World Bank (2005), Global Volcano Total Economic Loss Risk Deciles, Center for Hazards and Risk Research (CHRR)/Columbia University, Palisades, NY, http://sedac.ciesin.columbia.edu/data/set/ndh-volcano-total-economi...
