The Guaymas Basin is an active tectonic basin with hydrothermal activity that is known for its natural oil discharge sites.
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.
Read more at MARUM - Center for Marine Environmental Sciences, University of Bremen
