CAREER: A Molecular Level Investigation of Halogenation as a Mechanism of Trace Gas Production and Organic Carbon Transformation at the Surface Ocean

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Halogenation occurs when elements such as chlorine and bromine are added to organic compounds in the ocean. This process can produce gases that damage the ozone layer. Halogenation in the ocean is not well understood because most halogen-containing molecules remain unknown. Understanding halogenation in seawater is key because: (1) it may control recovery of the ozone hole as the Montreal Protocol phases out the use of man-made ozone-depleting substances and (2) some halogen-containing molecules can contribute to removing carbon dioxide from the atmosphere. This CAREER research project will develop new analytical and data science tools that can be used to identify halogen-containing molecules in the marine environment. The research also contributes to public health because damage to the ozone layer in the stratosphere is known to increase risks for skin cancer and cataracts. This CAREER research project includes educational activities to improve scientific literacy and to train the next generation of scientists and policymakers. Project activities include: (1) cutting-edge research training for undergraduate and graduate students, (2) partnerships with high school teachers to develop teaching materials, and (3) building relationships with communities underrepresented in STEM by working with established outreach programs led by the Texas Sea Grant Program.The motivation for this NSF CAREER research project is that organic carbon (OC) halogenation simultaneously affects the carbon cycle and atmospheric chemistry, contributing to stratospheric ozone depletion. The overarching research goal of this CAREER project is to identify the molecular-level chemical drivers of volatile and non-volatile halogenated organic carbon (VHOC and HOC) formation in the surface ocean. A series of laboratory experiments, student-led field observations, untargeted analyses using high-resolution mass spectrometry, and novel data pipelines will be used to achieve this goal through the pursuit of four specific research objectives: (1) identify OC moieties susceptible to halogenation, (2) identify VHOC precursor compounds in halogenation and assess production efficiency in single model compounds and complex mixtures, (3) identify HOC precursor compounds, trace HOC products, and predict their stabilities, and (4) determine the natural occurrence and chemical characteristics of HOC in the ocean. These research objectives are integral to the educational objectives. HOC characterization in the ocean will be achieved through annual undergraduate student-led cruises that will expose students to cutting-edge research. High school teachers will be funded in the summer to contribute to laboratory experiments alongside the Principal Investigator (PI) and graduate and undergraduate students. The collaboration between the PI and teachers will be used to develop high school instructional resources and classroom activities for a Marine Organic Biogeochemistry curriculum. Research results from this CAREER research will be synthesized and communicated to underrepresented communities through collaboration with the statewide network of the Texas Sea Grant agents, specialists, and communicators. This project will produce a first-of-its-kind HOC library and time series in the Gulf of Mexico that will provide a solid foundation for future HOC research by the broader scientific community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.