Award: OCE-1333162

The intellectual merit associated with this project includes the findings presented in nine resulting publications. Key findings focus on an improved understanding of the processes that impact hydrocarbons in the ocean, notably, the interplay between chemical processes driven by sunlight and biological processes. The findings of this work identify reactivity and tendencies for inventories of chemical compounds, including those that are spilled to the ocean through accidental spills. As example, this work effectively differentiated the behavior of hydrocarbons that sink to the deep ocean versus those that float at the ocean?s surface. In the deep ocean there is no sunlight, but nutrients tend to be abundant, and hydrocarbons are subject to biodegradation by microbes. However, the process by which microbes degrade oil was found to be sensitive to key factors related to the extent of contamination, temperature, and to the chemical structures of the compounds. In contrast, the surface of the open ocean presents a different setting, where sunlight can directly degrade hydrocarbons and where nutrient deprivation can prevent microbial degradation. Through this research project we have developed an improved understanding of the interplay between these various processes in the context of the ocean. Broader impacts associated with this project included training of undergraduate students, graduate students, and postdoctoral scholars. This work also resulted in impacts on a broader community, including participation of project personnel in a military exercise, where they were brought in to provide topical expertise relating to the fate and impact of ocean hydrocarbons related to mitigating the environmental impacts of a military strike on a refueling vessel. Furthermore, this project enabled project personnel to continue engagement providing unbiased information to policy makers considering issues related to hydrocarbons and the ocean, including participation on two study panels of the National Research Council. Finally, the research expedition associated with this project provided a formal opportunity for undergraduate students to learn about oceanographic research, through participation in a two quarter course series culminating in the research expedition. Last Modified: 12/18/2018 Submitted by: David L Valentine