Assoc. Prof. Dr. Eoghan P. Reeves 

Hydrothermal vents (black smoker chimneys) are one of the most well-known and spectacular features recognized in the deep ocean. Few realize, however, how little is known about these environments and the microbial life they host, especially when they cease venting activity and become extinct. Extinct chimneys may remain on the seafloor for thousands of years, hosting very diverse microbial communities of unknown function. They are now a key target for deep-sea mining as they are argued to contain key metals (such as copper) relevant for the green transition.

Given that all life is bound by lipids, this proposal’s primary aim is to use microbial lipid carbon and its stable carbon isotope ratios to illustrate changes in carbon flow processes occurring when chimneys stop venting fluid. This information will help understand how quantitatively important these extinct structures are to the biology and chemistry of the deep ocean at a time of intense societal pressure.

The organic chemical makeup of seafloor hydrothermal systems is also in general poorly understood, and so a secondary objective of this fellowship will be to shed new light on novel organic molecules carried in the black smoker fluids themselves, and how they relate to either life’s origins, or remnants of extant microbial life in these systems. The renowned Bremen-Oldenburg alliance of cutting-edge organic geochemistry activity is an ideal nexus to fundamentally address both research objectives.