Processes at shallow water gas seeps (PAGS)


Coordination: Miriam Weber, Christian Lott

Seeps of methane, carbon dioxide and other gasses out of the earth's interior is extraordinary relevant for the interaction of geological and atmospherical processes. The effect of methane as greenhouse gas is about 30fold of carbon dioxide. Biological processes within the seafloor induce a partly or complete conversion of those substances long before the actual seeping takes place, thus being crucially important for the natural release regulation of these greenhouse gasses. Processes like anaerobic oxidation of methane (AOM) via bacteria and/or archaea, or more likely via consortia of representatives of both groups, are already known of but not by far yet decrypted or understood.

We are observing gas seeps near the coast of Elba Island since 1995. First analyses revealed the mysterious bubbles being methane in fact. The continuity of the seeps suggest the likelihood of being thermogenic i.e. from the earth's interior ascending methane - not the product of surface near decay of organic material. analyses of isotopes revealed a extraordinary high fraction of the stable carbon isotope 13C, also suggesting a thermogenic genesis of the methane.

We are interested in the bacterial communities on an in the seafloor, the meio- and microfauna near the gas seeps and the biogeochemical processes within their reach. Field analyses are supplemented with incubation experiments in the lab under diverse conditions of pressure and concentrations. During our annual course Methods of Underwater Research we repeatedly accomplished measurements of the gas flow. Besides we plotted about 15 actual seep sites. The taken samples are further analyzed at the Max-Planck-Institute for Marine Microbiology in Bremen.


Hanna Kuhfuß, student from Freiburg, accomplished a laboratory at MPI during spring 2010, analyzing the molecular biology of the sediment samples taken by the course Methods of Underwater Research in 2009. Under the supervision of Katrin Knittel she studied the distribution and identities of bacteria and archaea oxidizing anaerobically the methane. The first results are quite promising.


Aggregates of bacteria and archaea running anaerobic oxidation of methane (AOM)


Johanna Wiedling from Greifswald is working at samples from the methane seep site taken by the course Methods of Underwater Research in 2009 as well. She studies under the supervision of Anna Lichtschlag at MPI MM the biochemistry of the sediment and the porewater. Together with Patrick Meister, MPI as well, Johanna tries to reveal the building of lime crusts an rests of seagrass rhizomes within the reach of the gas seeps. The processes leading to the creation of lime 50 cm deep within almost straight silicate sand is not yet understood.



Dr. Christian Deusner, Dr. Gunter Wegener, Thomas Holler (Max-Planck-Institute for Marine Microbiology in Bremen): Cultivation of barophilic bacteria, AOM
Dr. Dirk de Beer, Dr. Anna Lichtschlag (Max-Planck-Institute for Marine Microbiology in Bremen): Biogeochemistry, Microsensors
Dr. Katrin Knittel, Nicole Rödiger (Max-Planck-Institute for Marine Microbiology in Bremen): Molecular Ecology of ANME-Consortia
Hanna Kuhfuß (Uni Freiburg i. Br.): Molecular Biological studies on sediments near methane gas seeps
Johanna Wiedling (Uni Greifswald): Biogeochemistry and Meiofauna of sediments at methane gas seeps
Dr. Patrick Meister (Max-Planck-Institute for Marine Microbiology in Bremen): Calcification, Dolomitization