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| Titel |
A transfer function for the prediction of gas hydrate inventories in marine sediments |
| VerfasserIn |
M. Marquardt, C. Hensen, E. Piñero, K. Wallmann, M. Haeckel |
| 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 ; 7, no. 9 ; Nr. 7, no. 9 (2010-09-24), S.2925-2941 |
| Datensatznummer |
250004976
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| Publikation (Nr.) |
 copernicus.org/bg-7-2925-2010.pdf |
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| Zusammenfassung |
A simple prognostic tool for gas hydrate (GH) quantification in marine
sediments is presented based on a diagenetic transport-reaction model
approach. One of the most crucial factors for the application of diagenetic
models is the accurate formulation of microbial degradation rates of
particulate organic carbon (POC) and the coupled formation of biogenic
methane. Wallmann et al. (2006) suggested a kinetic formulation considering
the ageing effects of POC and accumulation of
reaction products (CH4, CO2) in the pore water. This model is
applied to data sets of several ODP sites in order to test its general
validity. Based on a thorough parameter analysis considering a wide range of
environmental conditions, the POC accumulation rate (POCar in g/m2/yr)
and the thickness of the gas hydrate stability zone (GHSZ in m) were
identified as the most important and independent controls for biogenic GH
formation. Hence, depth-integrated GH inventories in marine sediments (GHI
in g of CH4 per cm2 seafloor area) can be estimated as:
GHI = a · POCar · GHSZb · exp (– GHSZc/POCar/d) + e
with a = 0.00214, b = 1.234, c = –3.339,
d = 0.3148, e = –10.265.
The transfer function gives a realistic first order approximation of the
minimum GH inventory in low gas flux (LGF) systems. The overall advantage of
the presented function is its simplicity compared to the application of
complex numerical models, because only two easily accessible parameters need
to be determined. |
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