Ninth international conference on - Marum

20
Abstracts of oral presentations
rates reached 6 mMol⋅gDW -1 ⋅d -1 . It was shown that the process was insensitive towards changing substrate
concentrations and the accumulation of dissolved sulfide of up to 18 mM. Furthermore, the biomass could
survive prolonged periods of starvation. After eight weeks of incubation without supplying substrate, analysis of
total biomass indicated than no significant degradation of biomass took place. Cell integrity was confirmed by
FISH (Fluorescent In Situ Hybridization) analysis. AOM activity was re-established after supplying methane
without measurable lag phase.
Unexpectedly, in experiments where we varied biomass density, AOM rates at high methane partial pressure
were not dependent on biomass concentration. FISH analysis with specific probes revealed the enrichment of
sulfate-reducing bacteria (SRB) as compared to ANME. This is in contrast to batch incubation at near
atmospheric pressure where usually ANMEs are enriched compared to sulfate reducing bacteria. This
observation combined with the apparent process stability towards changing incubation conditions and the high
methane turnover rates suggest that both ANME and SRB are active in the catalysis of methane oxidation and
that the biochemical system and the physiological coupling of the organisms must allow a high degree of both
flexibility and efficiency towards changing availabilities of C1 compounds.
Possible BSR reflections on high resolution multichannel seismic reflection profiles from western
Black Sea continental slope
D. Dondurur 1 , S. Coşkun 1 , S. Gürçay 1 , S. Okay 1 , P. Özer 1 , G. Çifçi 1 , M. Ergün 1
1 Dokuz Eylül University, Institute of Marine Sciences and Technology, Inciraltı, Izmir, Turkey
Black Sea is an interesting semi-isolated basin with occurrences of several gas-related processes. Abundant
organic matter supply and rapid sediment deposition cause high amounts of shallow gas accumulations as well as
gas hydrate formations in deeper basin, and pockmarks, gas seeps and mud volcanoes are common all around the
basin.
Approximately 360 km of high resolution multi-channel seismic reflection data were collected together with
high resolution 3.5 kHz Chirp profiles from the western Black sea continental slope using a 96 channel seismic
recorder and 45+45 inch 3 GI gun in order to map possible shallow gas accumulations as well as gas hydrate
formations appears as Bottom Simulating Reflections (BSR) on the seismic lines. On the processed lines, some
very high amplitude reflections which mimic the seabed were observed (Fig. 1). They lie approximately 200 ms
below the sea floor and appear just below the channel banks, and therefore they are interpreted as BSR
reflections associated with the channel-levee systems.
We also computed complex trace attributes of these anomaly reflections and obtained reflection strength
(envelope), apparent polarity and instantaneous frequency sections. BSR reflections which were observed have
very large amplitude with negative polarity with respect to the seabed reflection as usual case.
Fig. 1: Multichannel seismic reflection data from western Black Sea slope showing a BSR reflection.