Marine organic compounds are produced in the ocean surface through photosynthesis and are modified by bacteria or zooplankton; some are preserved by interaction with minerals. Dr. Liu’s research investigates the source, distribution, and changes of organic compounds in marine environments. Knowing geochemical behaviors of organic compounds is critical for a better understanding of global carbon cycle and nutrient dynamics. Dr. Liu is also interested in geochemical behaviors of petroleum hydrocarbons in marine environments. More recently, he's turned his attention to nurdles, small bits of plastic that are increasingly appearing in marine environments, to find out what toxins they may be absorbing and passing along to wildlife.