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| Titel |
Modelling the impact of Siboglinids on the biogeochemistry of the Captain Arutyunov mud volcano (Gulf of Cadiz) |
| VerfasserIn |
K. Soetaert, D. Oevelen, S. Sommer |
| 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 ; 9, no. 12 ; Nr. 9, no. 12 (2012-12-21), S.5341-5352 |
| Datensatznummer |
250007474
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| Publikation (Nr.) |
 copernicus.org/bg-9-5341-2012.pdf |
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| Zusammenfassung |
A 2-Dimensional mathematical reaction-transport model was developed to study the impact of the mud-dwelling frenulate tubeworm
Siboglinum sp. on the biogeochemistry of a~sediment (MUC15) at the Captain Arutyunov mud volcano (CAMV). By explicitly
describing the worm in its surrounding sediment, we are able to make budgets of processes occurring in- or outside of the worm,
and to quantify how different worm densities and biomasses affect the anaerobic oxidation of methane (AOM) and sulfide
reoxidation (HSox).
The model shows that, at the observed densities, the presence of a thin worm body is sufficient to keep the upper 10 cm
of sediment well homogenised with respect to dissolved substances, in agreement with observations. By this "bio-ventilation"
activity, the worm pushes the sulfate–methane transition (SMT) zone downward to the posterior end of its body, and
simultaneously physically separates the sulfide produced during the anaerobic oxidation of methane from oxygen. While there is
little scope for AOM to take place in the tubeworm's body, 70% of the sulfide that is produced by sulfate
reduction processes or that is advected in the sediment is preferentially shunted via the organism where it is oxidised by
endosymbionts providing the energy for the worm's growth. The process of sulfide reoxidation, occurring predominantly in the
worm's body is thus very distinct from the anaerobic oxidation of methane, which is a diffuse process that takes place in the
sediments in the methane-sulfate transition zone. We show how the sulfide oxidation process is affected by increasing densities
and length of the frenulates, and by upward advection velocity.
Our biogeochemical model is one of the first to describe tubeworms explicitly. It can be used to directly link biological and
biogeochemical observations at seep sites, and to study the impacts of mud-dwelling frenulates on the sediment biogeochemistry
under varying environmental conditions. Also, it provides a tool to explore the competition between bacteria and fauna for
available energy resources. |
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