Fates of hydrocarbons in the deep-sea hydrothermal environments: Insights from molecular mechanical simulations


ORI Funded Research: 2011


Understanding the chemistry of hydrocarbons in the deep-sea hydrothermal environments is important, not only because of their roles in the marine carbon cycle, but also because of their astrobiological implications since several theories propose that life on Earth originated in submarine hydrothermal systems. However, despite intense research, the exact origins and reaction dynamics of these hydrocarbons remain difficult to determine.  This is mainly due to the complex reaction networks involved in hydrothermal environments and the difficulty to precisely control experimental conditions in the laboratory experiments. 

To circumvent these difficulties, I propose to model the hydrocarbon production and decomposition under hydrothermal conditions based on molecular mechanical methods (i.e., the ReaxFF reactive force field), using the high performance computation facility recently established in WHOI. With these theoretical modeling, I will identify and select individual reactions of most interest, study them in detail under precisely controlled conditions, and, more importantly, gain mechanistic understandings of the reaction processes.

This project constitutes the first systematic effort to theoretically model the hydrocarbon chemistry under hydrothermal conditions using molecular mechanical methods.  With the ReaxFF reactive force field simulations, I will investigate the role of heterogeneous catalysts, the temperature and pressure dependences of hydrothermal reactions, and the polymerization of simple hydrocarbons to form longer-chain hydrocarbons under hydrothermal conditions. Results from these theoretical modeling will produce valuable insights on the mechanisms of hydrocarbon production and decomposition in these environments, and provide a general framework to understand their concentrations and isotope compositions in natural hydrothermal systems.  This work will greatly complement WHOI’s existing research strength in hydrothermal chemistry and the ongoing experimental efforts in the Institution.