AGU: Geophysical Research Letters

 

Editors' Highlight

Measuring pollution from ice cores

Organic and elemental carbon in snow and ice can be used as chemical signatures of pollution. While elemental carbon is believed to be stable, the concentration of organic compounds in snow and ice may be affected by postdepositional processes. To study this, Hagler et al. (2007) analyzed snow from the Greenland ice sheet's surface and from a 3-m snow pit. Within the snow pit, they found that water-soluble organic carbon comprises about 89% of carbonaceous species, followed by water-insoluble particulate organic carbon (10%) and particulate elemental carbon (1%). The enhancement of organic carbon relative to elemental carbon suggests that gaseous organics are a major source of organic carbon found in snow. Comparisons of summer surface snow in 2006 with summer snows uncovered by the snow pit from 2002 to 2005 reveal that the ratio of organic carbon to elemental carbon decreases significantly for three of the four surveyed years. The substantial loss of organic carbon in aged snow suggests that postdepositional processes, such as photochemical reactions, must be considered before linking ice core records of organics to atmospheric concentrations.

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