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| Titel |
Transfer of organic Br and Cl from the Biosphere to the Atmosphere during the Cretaceous/Tertiary Impact: Implications for the stratospheric Ozone Layer |
| VerfasserIn |
K. Kourtidis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 5, no. 1 ; Nr. 5, no. 1 (2005-01-26), S.207-214 |
| Datensatznummer |
250002217
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| Publikation (Nr.) |
 copernicus.org/acp-5-207-2005.pdf |
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| Zusammenfassung |
| Following the Cretaceous/Tertiary (K/T) meteoritic
impact some 65Myr ago, large portions of aboveground terrestrial biomass
were burned. As a result, large amounts of various trace gases were injected
to the atmosphere, inducing a wide range of effects on climate and
ecosystems. Here, it is commented on the previously unaccounted for emission to
the atmosphere of methyl bromide (CH3Br) and methyl chloride
(CH3Cl) from extensive biomass burning that followed the impact. Based
on reported biomass burning emission rates of the above organohalogens
relative to CO2, it is estimated that their emissions from global fires
resulted in tropospheric mixing ratios of around 20-65.8ppbv organic Cl and
110-390pptv organic Br. The above calculated mixing ratios of organic
chlorine and bromine are more than an order of magnitude greater than their present,
anthropogenically perturbed level and, although the ocean ultimately might
absorb them, we argue here that they could still remain in the atmosphere
for many years, and a substantial fraction could be transported to the stratosphere, thus
substantially affecting the ozone layer. This would have
led to very serious increases in short wavelength UV radiation reaching the
lowermost atmosphere. |
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