New study on natural oil seeps in the deep sea

The Guaymas Basin is an active tectonic basin with hydrothermal activity that is known for its natural oil discharge sites. Here, microorganisms use the seeping oil as a source of energy and nutrition and thereby fuel the carbon cycle. Because microorganisms preferentially break down water-soluble organic molecules, it is important to understand how hydrothermal processes mobilize DOM, for example, those from natural oil seeps. To date, the mechanisms underlying this mobilization have not been well characterized.

Analyses carried out by the team have revealed that the composition of the released water-soluble organic molecules, or DOM, is strongly influenced by the temperature of the hydrothermal systems and the composition of the petroleum.

Their results indicate that hydrothermal sediments are a source of bioavailable organic molecules — compounds that microorganisms can degrade relatively quickly. At the same time, they can also release more stable and complex DOM, including water-soluble petroleum compounds that may persist in the deep sea over millennia, according to the study. These findings, now published in the journal Limnology and Oceanography, suggest that these hydrothermal systems may influence not only on local ecosystems, but also broader regions of the deep sea. The authors therefore emphasize the need for more quantitative research on the contribution of hydrothermal sediments to the DOM cycle — not only in the deep sea but also in the context of the global marine carbon cycle. In addition, the Guaymas Basin could be a source for what is known as black carbon. These complex and persistent carbon compounds are resistant to rapid microbial degradation and their origin is still not fully understood.

Participants in the study from MARUM – Center for Marine Environmental Sciences at the University of Bremen included Dr. Florence Schubotz, and first author Jonas Brünjes who is now at the University of Toronto (Canada), Dr. Michael Seidel from the Institute for Chemistry and Biology of the Marine Environment (ICBM) at the University of Oldenburg, and Prof. Andreas Teske of the University of North Carolina (USA).

Deciphering the sources and sinks for dissolved organic matter and its quantitative significance in the marine carbon cycle is also an integral element within the Cluster of Excellence “Ocean Floor - Earth's Uncharted Interface”, within the framework of which the study was supported.

More information on this topic:

https://www.marum.de/en/Laboratory-experiment-identifies-asphalt-as-a-source-for-non-degradable-carbon-and-sulfur-compounds-in-the-ocean.html

Contact:

Dr. Florence Schubotz
MARUM – Center for Marine Environmental Sciences, University of Bremen
Telephone: 0421 – 218 65724
Email: fschubotz@marum.de
https://www.marum.de/Dr.-florence-schubotz.html

Dr. Michael Seidel
Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg
Telephone: 0441 – 798 3768
Email: m.seidel@uol.de
https://uol.de/en/icbm/marine-geochemistry/staff/dr-michael-seidel

MARUM produces fundamental scientific knowledge about the role of the ocean and the ocean floor in the total Earth system. The dynamics of the ocean and the ocean floor significantly impact the entire Earth system through the interaction of geological, physical, biological and chemical processes. These influence both the climate and the global carbon cycle, and create unique biological systems. MARUM is committed to fundamental and unbiased research in the interests of society and the marine environment, and in accordance with the Sustainable Development Goals of the United Nations. It publishes its quality-assured scientific data and makes it publicly available. MARUM informs the public about new discoveries in the marine environment and provides practical knowledge through its dialogue with society. MARUM cooperates with commercial and industrial partners in accordance with its goal of protecting the marine environment.

The Institute for Chemistry and Biology of the Marine Environment (ICBM) is an interdisciplinary Institute at the University of Oldenburg with locations in Oldenburg and Wilhelmshaven. It is the only university institute in Lower Saxony that covers broad areas of marine sciences, both in research and in teaching. Currently, 26 working groups of various scientific disciplines - including biology, chemistry, physics, mathematics and social sciences - belong to the institute. ICBM operates the Spiekeroog Coastal Observatory and is the home institute of the research vessel SONNE.