نتایج جستجو برای: atmospheric co2
تعداد نتایج: 142185 فیلتر نتایج به سال:
Global measurement of atmospheric CO2 concentration from space is greatly desired for global and regional carbon budget studies. The biggest challenge for CO2 remote sensing from space is to achieve the high-precision science measurement requirement (~ 1 ppmv or 0.3% on regional scales) so that the satellite measurements will be able to remarkably reduce current large uncertainties about carbon...
The decline of atmospheric CO2 over the last 65 million years (Ma) resulted in the 'CO2-starvation' of terrestrial ecosystems and led to the widespread distribution of C4 plants, which are less sensitive to CO2 levels than are C3 plants. Global expansion of C4 biomass is recorded in the diets of mammals from Asia, Africa, North America, and South America during the interval from about 8 to 5 Ma...
[1] Monthly estimates of the global emissions of anthropogenic CO2 are presented. Approximating the seasonal CO2 emission cycle using a 2-harmonic Fourier series with coefficients as a function of latitude, the annual fluxes are decomposed into monthly flux estimates based on data for the United States and applied globally. These monthly anthropogenic CO2 flux estimates are then used to model a...
Recently, it was proposed (Baum, 1990 and Martin et al., 1990a, 1990b) that the southern ocean should be fertilized with iron to stimulate biological productivity, thus enhancing the flux of organic carbon from surface to depth, thereby lowering the concentration of inorganic arbon in surface water and in turn the atmospheric CO2 concentration. We explore the possible impact of a hypothetical i...
The ability of gold-hydroxides to fix CO2 is reported. [Au(IPr)(OH)] and [{Au(IPr)}2(μ-OH)][BF4] react with atmospheric CO2 to form the trigold carbonate complex [{Au(IPr)}3(μ(3)-CO3)][BF4]. Reactivity studies revealed that this complex behaves as two basic and one cationic Au centres, and that it is catalytically active. DFT calculations and kinetic experiments have been carried out.
[1] The carbon and oxygen isotopes of CO2 and the oxygen isotopes of H2O are powerful tracers for constraining the dynamics of carbon uptake and water flux on land. The role of land biota in the atmospheric budgets of these isotopes has been extensively explored through the lens of leaf-scale observations. At the ecosystem scale, kinetic fractionation is associated with molecular and turbulent ...
BACKGROUND AND AIMS Global climate models predict decreases in leaf stomatal conductance and transpiration due to increases in atmospheric CO2. The consequences of these reductions are increases in soil moisture availability and continental scale run-off at decadal time-scales. Thus, a theory explaining the differential sensitivity of stomata to changing atmospheric CO2 and other environmental ...
Although it is widely acknowledged that rising atmospheric CO2 concentrations will increase crop root growth, no study has considered how this response could be influenced by agricultural management practices. Therefore, we examined the influence of elevated atmospheric CO2 (ambient + 360 mmol mol ) on root dynamics of sorghum (Sorghum bicolor) produced under conventional (tillage following win...
A three dimensional, time-evolving field of atmospheric potential oxygen (APO ∼O2/N2+CO2) was estimated using surface O2, N2 and CO2 fluxes from the WHOI ocean ecosystem model to force the MATCH atmospheric transport model. Land and fossil carbon fluxes were also run in MATCH and translated into O2 tracers using assumed O2:CO2 stoichiometries. The modeled seasonal cycles in APO agree well with ...
Two experiments were conducted to study the effects of increased atmospheric nitrogen deposition and elevated CO2 on investment in carnivory by two sundew species, Drosera rotundifolia and D. intermedia. A field study was conducted with D. rotundifolia at Inverness Mud Lake Bog in Inverness Twp., MI where plants were exposed to simulated future increases in atmospheric nitrogen deposition predi...
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