Results 1 - 10 of 2028
Results 1 - 10 of 2028. Search took: 0.023 seconds
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[en] Global anthropogenic pollution of the biosphere is one of the most actual problems of the modern era from the protecting view point of the environment. Radionuclide contamination in some areas doesn't keep one of the last places in this process. So, the practical activity of human has caused the changing of the radio ecological condition of the living environment, regular increasing of natural radiation background in everywhere, the acceleration of the migration flow of natural and artificial radionuclide, the increasing of local areas highly contaminated with radionuclides and so on.
[en] Protecting Earth and planets against the invasion of 'alien life forms' is not military science fiction, but it is the peaceful daily job of engineers and scientists of space agencies. 'Planetary Protection' is preventing microbial contamination of both the target planet and the Earth when sending robots on interplanetary space mission. It is important to preserve the 'natural' conditions of other planets and to not bring with robots 'earthly microbes' (forward contamination) when looking for 'spores of extra terrestrial life'. The Earth and its biosphere must be protected from potential extraterrestrial biological contamination when returning samples of other planets to the Earth (backward contamination). The NASA-Caltech Laboratory for Planetary Protection of Dr. Kasthuri Venkateswaran at the Jet Propulsion Laboratory (JPL) (California, USA) routinely monitors and characterizes the microbes of NASA spacecraft assembly rooms and space robots prior to flight. They have repeatedly isolated Cupriavidus and Ralstonia strains pre-flight from spacecraft assembly rooms (floor and air) and surfaces of space robots such as the Mars Odyssey Orbiter (La Duc et al., 2003). Cupriavidus and Ralstonia strains have also been found in-flight, in ISS cooling water and Shuttle drinking water (Venkateswaran et al., Pyle et al., Ott et al., all unpublished). The main objective of this study is to characterise the Cupriavidus and Ralstonia strains isolated at JPL and compare them to the Cupriavidus metallidurans CH34T model strain, isolated from a Belgian contaminated soil and studied since 25 years at SCK-CEN and to enhance our knowledge by performing additional tests at JPL and gathering information regarding the environmental conditions and the cleaning and isolation methods used in such spacecraft assembling facilities
[en] The study concerning carbon dioxide measurements taken during the 1997, 1998 and 1999 summer campaigns at two different altitude stations and biospheric conditions are presented. The higher station (Mt. Cimone, 2165 m a.s.l.) is characterised by 360o free horizon and is located on a rocky mountain while the lower (Ninfa lake, 1550 m a.s.l.) is located inside the red spruce and beech forest. The different behaviour of CO2 at the two mountain stations has been registered. It shows the strong effect of nighttime soil emission and vegetation respiration on CO2 mixing ratio increases and of diurnal vegetative activity on CO2 concentration decreases at the lower measurement site. The baseline character of the higher measurement site has been confirmed by comparison of CO2 diurnal amplitudes recorded at the two stations. (author)
[en] In the paper the investigation method of dynamic change of the concentration level of radioactive pollutant elements with half-lifeT1/2> 1 year on the land depended on year season has been considered. The method of variance mathematical analysis has been considered for study of dynamic of the oscillation of measured values.
[en] Full text: Water, carbon and oxygen fluxes in the biosphere are tightly coupled physically and functionally. A unique aspect of these interactions is the transfer of 18-O label from the hydrological cycle to the carbon and oxygen cycles. Fractionations in the hydrological cycle results in large meridional and continental gradients in the 18-O content of meteoric water on land. This labeling is transferred to CO2 via CO2 dissolution in water and subsequent oxygen exchange; and to O2 via the water splitting reaction in photosynthesis. The 18-O labeling of atmospheric CO2 provides, in turn, a powerful tracer of sinks and sources of carbon in ecosystems. The 18-O label of O2 provides, in addition, a global-scale indicator of ocean--land partitioning of biospheric productivity. In both cases, modifications in the 18-O label of the atmospheric gases are coupled to changes in the hydrological cycle. I will discuss the major developments in understanding the processes underlying the 18-O links in the H2O-CO2-O2 system and the insights they provide to hydrosphere-biosphere interactions. (author)
[en] There are approximately 4 million km2 of peatlands worldwide, covering some 3 % of the land surface. Their exact extent is uncertain within 150 000 km2 or so. This is partly because of the difficulty of defining their boundaries precisely, and partly from simple lack of information, especially from parts of Canada and the former USSR, and within the tropical regions. Over 90 % of peatlands are in the temperate and cold belt in the Northern Hemisphere. It is estimated that almost 95 % of peatlands are found in just eight nations: CIS (former USSR) (38 %); Canada (28 %); USA (15 %); Indonesia (6 %); Finland (3 %); Sweden (2 %); China (1 %); Norway (1 %). European peatlands excluding the former USSR amount to just 7 % of the total area. African and South American peatlands each account for 1 % of the total. Central America holds less than 1 % of the global total. Tropical peatlands may account for as much as 10 % of the total area, and more than 7 % of the world total is in south-east Asia alone. The significance of the very large carbon store represented by the world's peatlands in relation to global carbon cycling, and the potential for global environmental change, is becoming increasingly apparent. In this chapter also the conditions for the formation of peat, limits of peat growth, element accumulation, nutrient cycling and budgets of peatlands are discussed. (29 refs.)
[en] In this annual report the results and conclusions are given of radioactive and xenobiotic substances in the biosphere of the Netherlands. The measurements are coordinated by the Coordination Committee for the Monitoring of Radioactive and Xenobiotic substances. (Auth.)
[en] The Biological Resources Mitigation Strategy (BRMiS), as part of a broader biological resource policy, is designed to aid the U.S. Department of Energy, Richland Operations Office (DOE-RL) in balancing its primary missions of waste cleanup, technology development, and economic diversification with its stewardship responsibilities for the biological resources it administers. This strategy will be applied to all DOE-RL programs as well as all contractor and subcontractor activities
[en] There have been two nuclear power plants (NPPs) in operation in Slovakia - Jaslovske Bohunice and Mochovce. Radiocarbon as one of the most important radionuclides for delivering of long-term radiation doses to the public has been regularly monitored in the NPP surrounding areas as well as in the city of Bratislava. In the vicinity of both NPPs atmospheric carbon dioxide has been sampled on a monthly basis and its radiocarbon activity has been measured by gas proportional counting. The atmospheric 14CO2 data from these two sampling stations will be presented and compared with results from other sampling sites from both urban and rural parts of Slovakia. Carbon dioxide is assimilated by plants during photosynthesis and therefore connects radiocarbon in the atmosphere with the surrounding biosphere. Therefore, stinging nettle samples were taken from the sampling area for comparison with the atmospheric data. These biota samples provide information about 14C activity accumulated during given plants' growth. Annual tree rings have been used as an archive of past radiocarbon levels in the biosphere as well. Tree ring samples from the Jaslovské Bohunice area covering a period of 20 years, measured by accelerator mass spectrometry, were compared with atmospheric radiocarbon data collected at the Jaslovské Bohunice and Bratislava (background) stations.