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| Titel |
Fluxes of microbes, organic aerosols, dust, sea-salt Na ions, non-sea-salt Ca ions, and methanesulfonate onto Greenland and Antarctic ice |
| VerfasserIn |
P. B. Price, R. A. Rohde, R. C. Bay |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 3 ; Nr. 6, no. 3 (2009-03-27), S.479-486 |
| Datensatznummer |
250003540
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| Publikation (Nr.) |
 copernicus.org/bg-6-479-2009.pdf |
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| Zusammenfassung |
| Using a spectrofluorimeter with 224-nm laser excitation and six emission
bands from 300 to 420 nm to measure fluorescence intensities at 0.3-mm depth
intervals in ice cores, we report results of the first comparative study of
concentrations of microbial cells (using the spectrum of protein-bound
tryptophan (Trp) as a proxy) and of aerosols with autofluorescence spectra
different from Trp (denoted "non-Trp") as a function of depth in ice cores
from West Antarctica (WAIS Divide and Siple Dome) and Greenland (GISP2). The
ratio of fluxes of microbial cells onto West Antarctic (WAIS Divide) versus
Greenland sites is 0.13±0.06; the ratio of non-Trp aerosols onto WAIS
Divide versus Greenland sites is 0.16±0.08; and the ratio of
non-sea-salt Ca2+ ions (a proxy for dust grains) onto WAIS Divide
versus Greenland sites is 0.06±0.03. All of these are roughly
comparable to the ratio of fluxes of dust onto Antarctic versus Greenland
sites (0.08±0.05). By contrast to those values, which are considerably
lower than unity, the ratio of fluxes of methanesulfonate (MSA) onto
Antarctic versus Greenland sites is 1.9±0.4 and the ratio of sea-salt
Na2+ ions onto WAIS Divide versus Greenland sites is 3.0±2. These
ratios are more than an order of magnitude higher than those in the first
grouping. We infer that the correlation of microbes and non-Trp aerosols
with non-sea-salt Ca and dust suggests a largely terrestrial rather than
marine origin. The lower fluxes of microbes, non-Trp aerosols, non-sea-salt
Ca and dust onto WAIS Divide ice than onto Greenland ice may be due to the
smaller areas of their source regions and less favorable wind patterns for
transport onto Antarctic ice than onto Greenland ice. The correlated higher
relative fluxes of MSA and marine Na onto Antarctic versus Greenland ice is
consistent with the view that both originate largely on or around sea ice,
with the Antarctic sea ice being far more extensive than that around
Greenland. |
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