POP:ART

This proposal requests ship time aboard the R/V Roger Revelle or R/V Sally Ride to perform a detailed characterization of the metabolomic and microbial succession on particles as they transit the euphotic zone of the California Current Ecosystem (CCE). This expedition will visit two sampling sites in the CCE: one coastal site within the CalCOFI sampling grid characterized by upwelling features and high levels of productivity. The second site will be located offshore in low-productivity oligotrophic waters. At each site, a drifting sediment trap array will be deployed and various shipboard operations will be conducted, including CTD casts, McLean Pump deployments, and snowcatcher deployments. Samples for sinking POM, suspended POM and dissolved organic matter will be collected for metabolomic and microbial community composition analysis. By combining nontargeted metabolomic techniques with metagenomic and metatranscriptomic analyses, we will link changes in particle composition to changes in the microbial community and microbial activity on the sinking material. This work will provide novel insights into the evolution of sinking particles and the mechanisms that control particle remineralization in the upper ocean.