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| Titel |
Methyl iodide production in the open ocean |
| VerfasserIn |
I. Stemmler, I. Hense, B. Quack, E. Maier-Reimer |
| 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 ; 11, no. 16 ; Nr. 11, no. 16 (2014-08-22), S.4459-4476 |
| Datensatznummer |
250117560
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| Publikation (Nr.) |
 copernicus.org/bg-11-4459-2014.pdf |
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| Zusammenfassung |
| Production pathways of the
prominent volatile organic halogen compound methyl iodide (CH3I) are not
fully understood. Based on observations, production of CH3I via
photochemical degradation of organic material or via phytoplankton
production has been proposed. Additional insights could not be gained from
correlations between observed biological and environmental variables or from
biogeochemical modeling to identify unambiguously the source of methyl iodide. In this study, we aim to
address this question of source mechanisms with a three-dimensional global
ocean general circulation model including biogeochemistry
(MPIOM–HAMOCC (MPIOM – Max Planck Institute Ocean Model HAMOCC –
HAMburg Ocean Carbon Cycle model)) by carrying out a series of
sensitivity experiments. The simulated fields are compared with a newly
available global data set. Simulated distribution patterns and emissions of
CH3I differ largely for the two different production pathways. The
evaluation of our model results with observations shows that, on the global
scale, observed surface concentrations of CH3I can be best explained
by the photochemical production pathway. Our results further emphasize that
correlations between CH3I and abiotic or biotic factors do not necessarily
provide meaningful insights concerning the source of origin. Overall, we find
a net global annual CH3I air–sea flux that ranges between 70 and
260 Gg yr−1. On the global scale, the ocean acts as a net source of
methyl iodide for the atmosphere, though in some regions in boreal winter,
fluxes are of the opposite direction (from the atmosphere to the ocean). |
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