Institut für Ostseeforschung Warnemünde
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Sebastian Jordan

Sebastian Jordan
Leibniz-Institute for Baltic Sea Research
Seestrasse 15
D-18119 Rostock
+49 381 5197 0
+49 381 5197 440

Research Focus

  • Transport of microorganisms in the marine habitat
  • Methane turnover in marine shallow seeps
  • Shift of methan oxidizing communities

Current Projects

Bubble Shuttle

Gas bubble releasing seep sites are relevant methane sources in aquatic systems. In the vicinity of these sites, methanotrophic microorganisms in the sediment and water column play a key role in controlling the methane flux into the atmosphere. Recent studies in the water column surrounding hydrocarbon seeps indicated an elevated abundance and activity of methanotrophic microorganisms in the near field of gas bubble plumes. During our pilot studies conducted at the Coal Oil Point Seep region in California (DFG project “Transport of methane oxidizing microorganisms from the sediment into the water column (Bubble Shuttle)” (SCHM 2530/3-1), we could show for the first time that methanotrophic bacteria were transported by gas bubbles from the sediment into the water column. Within this follow-up project we aim to support these first indications by conducting comprehensive studies on a variety of gas bubble releasing seep sites. The fundamental goal of our project is to evaluate the importance of such a transport mechanism on the pelagic methane turnover at these seep sites. Multidisciplinary studies at different seep locations located in the Coal Oil Point seep field and the North Sea will help us to discuss the different environmental factors, which control the transport efficiency of the bentho-pelagic gas bubble mediated exchange process. By integrating lab-based incubation experiments we will study the activity of seep-associated benthic methanotrophic bacteria in the pelagic environment. Additional phylogenetic analyses will be used to test our hypothesis that the gas bubble transport mechanism impacts the diversity of pelagic methanotrophic bacteria at seep sites. Field studies at a Blowout location in the North Sea and the integration of oceanographic measurements and models will be used to establish a budget for pelagic methanotrophic bacteria in the near field of seep sites. Overall, this approach will help us to discuss the impact of the bubble transport mechanism on the abundance of methanotrophic bacteria and the pelagic methane sink.

The North Sea

After two exhausting weeks on the Research Vessel POSEIDON (POS504, chief scientist Dr. Jens Schneider von Deimling; link) we got our first Bubble Catcher samples. The North Sea showed us its brutal and stormy side--we started the cruise with Beaufort 7 to 8 making the ROV useless. Fortunately, the sea calmed down after a few days and we were granted with a few days of diving. The ROV team from GEOMAR lead by Martin Pieper did a great job maneuvering the ROV PHOCA despite difficult conditions. Thus, it was possible to get the Bubble Catcher down to the bottom of the crater of the abandoned well 22/4b. It brought back samples and video material. In addition, we conducted CTD casts to survey the incoming and outgoing water masses. Microbial samples were fixed and filtered on board. Methane oxidation rates as well as sediment samples were obtained with the help of Prof. Tina Treude. Following are a few impressions of the work on the RV POSEIDON.

Impressions from the Cruise POS 504. The scientific crew is pictured in the middle. In the top left hand corner, the ROV PHOCA from the GEOMAR institute is pictured.

Santa Barbara

The five months in California flew by fast. We conducted our experiments in August and mid-September. Weather and diving conditions were great. We were able to conduct multiple experiments with our Bubble Catcher and collect samples as well as controls at two sites in front of Campus Point. Due to the shallow water depth, no ROV was needed. The scientific diving was carried out by the Marine Operation team of Christoph Pierre (UCSB) and our colleagues from the IOW Andreas Frahm and Jens Müller. Microbiological samples were processed directly at the University of California Santa Barbara (UCSB) in Dr. Uta Passow’s lab, whereas sediment samples and methane oxidation rates were measured at the University of California Los Angeles (UCLA) in the lab of Prof. Tina Treude. Dr. Ira Leifer used his Bubble Measuring System (BMS) to measure the bubble size distribution of the gas vents we sampled. Combining the size distribution and the bacteria counts, we are able to get an idea how many bacteria are transported per bubble.
I spent the remaining months analyzing the abundance of methane oxidizing bacteria (MOB) and began the new year with an interesting set of data and samples to be analyzed. I really enjoyed the time in south California. Everyone contributing to the project did a great job!

Impressions of the fieldwork in Santa Barbara. In the center photo, Andres Frahm, Sebastian Jordan, and Oliver Schmale (left to right) are pictured.

During the fieldwork, we filmed a lot, including two interviews explaing the project Bubble Shuttle and its scope.

Part 1 Interviewee Sebastian Jordan:

Part 2 Interviewee Ira Leifer:

Underwater pictures of the Bubble Catcher in action: ADCP measuring water current (top right), sediment coring and the blowout crater (top left). In the middle the ROV PHOCA is pictured, with the Bubble Catcher on its porch.