Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980

Stomatal density and stomatal index as indicators of paleoatmospheric CO2 concentration

“…The increase in atmospheric CO 2 concentration since industrialization (Friedli et al, 1986;Keeling et al, 1995) and the predicted continued increase into the near future (Houghton et al, 1995) forces the need to understand how the biosphere operates under elevated (relative to pre-industrial) CO 2 levels. The geologic record affords a wealth of such information.…”

“…a Typically between 340 and 360 ppmV; for herbarium studies, control corresponds with oldest material. b From direct measurements from Mauna Loa Observatory, Hawaii and South Pole (Keeling et al, 1995). c From Siple Station ice core (Neftel et al, 1985;Friedli et al, 1986 Freeman and Hayes, 1992;Cerling et al, 1997(c.f.…”

Determination of the 2H/1H, 17O/16O, and 18O/16O isotope ratios in water by means of tunable diode laser spectroscopy at 1.39 μm

“…For instance, isotopes can be used as tracers to study gas exchange between different compartments (reservoirs) of the environment. The 13 CO 2 / 12 CO 2 ratio is extremely useful to constrain the global atmospheric CO 2 budget [1][2][3][4][5], but also finds applications as a biomedical diagnostic tool, e.g. in the quantification of the amino acid metabolism by means of a 13 C-labeled leucine test [6 -8].…”

“…Moreover, whereas with IRMS one or more isotopomers may show up at the same mass, this is not an issue with isotope ratio infrared spectroscopy (IRIS). Thus, IRIS is able to measure the 2 Using a direct absorption spectrometer, we have already shown that IRIS can be applied successfully [17] to the measurement of isotope ratios in ice-cores (paleoclimatology) [18] and in the biomedical double-labeled water technique to quantify an organism's energy expenditure [19]. The laser source used in this case, is a commercial solid-state infrared laser (color center laser; Burleigh Inc. .…”

Effects of Elevated Atmospheric Carbon Dioxide Concentration on Silica Deposition in Rice (Oryza sativaL.) Panicle

“…Numerous studies suggested that the predicted increase in [CO 2 ] will promote the growth and yield of rice (Kimball and Idso, 1983;Imai et al, 1985;Ziska and Teramura, 1992;Keeling et al, 1995;Baker et al, 1997b). However, elevated [CO 2 ] reduces transpiration and other researchers predicted a decrease in rice yield in the event of a severe drought at a particularly sensitive growth stage such as anthesis and grain fi lling (Baker et al, 1997a).…”