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Project GB3

Contribution of cold seeps to geological processes, carbon fluxes, and ecosystems

A. Boetius, G. Bohrmann, H. Sahling, F. Wenzhöfer
D. de Beer, N. Dubilier, M. Elvert, T. Feseker, K.-U. Hinrichs, J. Notholt, T. Pape, V. Spieß, G. Wegener
Identification and quantification of spatial and temporal variations in geophysical, geological, biogeochemical and biological processes associated with hydrate formation and hydrocarbon gas emission from the seafloor
Cold seeps are sea floor structures, which emit hydrocarbon-rich fluids to the water column and potentially to the atmosphere. The objective of GB3 is the holistic understanding of the distribution and temporal development of cold seeps in coastal and deep-sea areas, to quantify their emissions and to characterize geochemical and microbial processes at these sites.
The emitted fluids are rich in chemical energy, which is efficiently harvested by assemblages of microorganisms and associated chemosynthetic symbionts. We aim to further describe those organisms, their functioning and diversity as well as their global distribution patterns.
Our research is based on the following key hypotheses:
Oceanic, sedimentary, and tectonic conditions have a major impact on gas hydrates, free gas formation and fluid migration
The distribution of gas hydrates and strength of hydrocarbon leakage determines the distribution and composition of microbial and faunal communities
Methane emission rates from the seabed into the ocean and the atmosphere have been underestimated due to incomplete knowledge of their spatial and temporal variability, their control mechanisms and transport pathways

Seafloor image taken sduring ROV QUEST Dive 130 at Amsterdam mud volcano Eastern Mediterranean.

Osmo sampler placed at a gas bubble site in 1000 m water depth over a bacterial mat, Makran subduction zone.

Gas emission sites on Dvurechenskii mud volcano of the Black Sea shown by PARASOUND.