Ice samples

Bacteria in thawed ice samples from Ellesmere Island (79°38 N, 74°23 W) produced CO2 and CH4 during extended incubation at 4°C in a diluted complex medium (yeast extract, casamino acids, starch, and glucose) (Skidmore et al. 2000). It was suggested that the results demonstrated that the subglacial environment beneath a polythermal glacier provided an acceptable habitat for microbial life. 

Interesting ice samples from Antarctica and Greenland have been and are being recovered. We studied samples of the Byrd core, which is a 12-cm-diameter core that extended to bedrock at 2100-m depth [1]. This core is presently kept at the Central Ice Core Storage Facility at S.U.N.Y. Buffalo (C. C. Langway, Jr., Curator). Its age-depth relationship has been calculated on the basis of rheological models [3,4,5], and comparisons of the 6180 variations of the core with those in the Camp Century (Greenland) core. The age calculated for the bottom ice is between 50 x 103 and 100 x 103 years. 

It is necessary to measure 14C in smaller ice samples to date specimens from the core itself. The uncertainties in the calculated age-depth relation increase with depth because it is difficult to measure 14C at large depths. Another radioactive dating method is desirable for the bottom half of the core 222Rn, can be extracted and counted by essentially the same procedure as 14C, and when combined with the measurement of 230Th, is a promising dating method for the core bottom. 

Most of the chemical analyses are performed after melting of the snow samples which subdivides the species into water-soluble and insoluble ones. The concentrations of trace species can vary by at least two orders of magnitude and the lowest values are in the range of 1-10 pg/1 for major ions such as Ca ", NH4, NOs , S04, and 10-100 ng/1 for trace metals. Thus, the snow and ice samples are particularly sensitive with respect to contamination and require special care in sample handling. 

The values of yS for the ice samples have been estimated from their Di(T) values assuming Eq. 9 with fco=lXlO s . (The value of ko was calculated from the DNA in D2O glass results)... 

One way scientists have learned about the levels of carbon dioxide in the past is through the analysis of ice cores. An ice core is a tube of ice, usually drilled out of a glacier or ice sheet, that contains bubbles of air trapped inside layers of snow and ice. Each layer of snow and ice represents roughly a year. The deeper the layer, the older the ice sample. From the size and chemical content of each layer, scientists can draw conclusions about the temperatures at that point in history at that spot on the planet. At the same time, the bubbles of air preserved in each layer contain indicators of the amount of atmospheric carbon dioxide present at that time. 

LA-ICP-MS is the method of choice for directly studying pollution in ice samples. Reinhardt and co-workers27 28 analyzed ice cores from the polar region by LA-ICP-MS employing a home made cryogenic laser ablation chamber. Selected trace elements (Mg, Al, Fe, Zn, Cd, Pb and some... 

Global releases of radium-226 by the combustion of coal have been estimated as 150 Ci (5,550,000,000 kBq) per year (Jaworowski et al. 1971). It has also been observed that radium-226 concentrations in glacial ice samples collected in Europe have increased by a factor of 100 during the last 80 years. The source of these elevated levels of radium may have been emissions from fossil fuels (Jaworowski et al. 1971). 

Junge K, Krembs C, Deming JW, Stierle A, Eicken H (2001) A microscopic approach to investigate bacteria under in-situ conditions in sea-ice samples. Ann Glaciol 33 304-310... 

PROBLEM A 28-gram sample of ice at 0°C completely melts and remains as a liquid at 0°C. How much heat was absorbed by the ice sample ... 

Fig. 3. COj and 5 0 measured on ice samples from the Dye 3 core in Greenland. The 30 m inaement in the core corresponds to about 10,000 years, between about 30 and 40,000 years BP. (From Oeschger and Stauffer, 1985).

Reimann et al. measured the fluence and temperature dependence for the production of O2 from a thin ice sample in a vacuum exposed to energetic Ne+ [Fig. 5(a)], These ions were used to represent the energetic O" " ions in the Jovian plasma. They found a correlation between the loss of... 

As Michalski and Thiemens (2000) have shown, aerosol nitrate possesses an extraordinarily large mass-independent isotopic composition. As for aerosol sulfate, this isotopic signature has already been shown to provide a new means to elucidate source and chemical transformation processes. This has proved to be an important technique by which the nitrate biogeochemical cycle may be understood further. For example, the massive mass-independent isotopic signature observed in Chilean desert nitrates uniquely reveals that these nitrates must be atmospherically derived since all other sources (by measurement) possess mass-dependent isotopic compositions. In addition, these measurements, coupled with contemporary aerosol nitrate measurements reveal that the oxygen isotopic signatures are stable on million year timescales. This is particularly valuable, as this permits measurement of nitrate in polar ice samples to examine paleo-variations in nitrate and in general, chemistry. As... 

A similar analysis for Pb yields the following results icesheet concentration ratio is about 15 and atmospheric emission ratio is about 20. While this is not too bad a comparison, it is not as good as for the other three metals (Zn-Cd-Cu). It is clear that most of the Pb increase in snow/ice samples from Greenland is due to the use of leaded gasoline after the 1950s (Murozumi et al., 1969). 

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