Award: OCE-1342734

In the world's oceans, the chemical dimethylsulfoniopropionate (DMSP) is produced by marine phytoplankton and released into the environment. A large portion of the DMSP is assimilated and/or degraded by marine bacteria. These bacteria can perform one of two globally-significant transformations when they come in contact with DMSP. One is converting it to a volatile sulfur gas that escapes into the atmosphere where it can influence the earth's climate; the other transformation converts DMSP into sulfur-containing amino acids that end up being consumed in the marine microbial food web. This project set out to understand the balance between these two pathways, because each takes DMSP-sulfur to a distinctly different biogeochemical fate, and future climate changes may influence the balance between these functions. The Monterey Bay Aquarium Research Institute has developed a robotic sampling instrument, the Environmental Sample Processor (ESP) that can be deployed in the ocean and remain for 30-45 days, collecting filter samples of seawater on a daily basis. Immediately after sampling, these filters are preserved, stopping microbial gene expression at the moment of collection. When the ESP is recovered, these filters are then available for detailed genetic analysis to see what genes have been expressed (i.e., 'turned-on') or not. These results can be correlated to properties measured in the water (e.g., temperature, salinity, etc.) to help us understand what environmental features might influence which pathway bacteria choose when processing DMSP. The ESP was deployed in Monterey Bay, CA for ~30 days in the fall of 2014 and fall of 2016, collecting 132 samples each time. Once back on shore, these samples (filters), were processed to release nucleic acids that would indicate who was collected and which genes they were expressing. In addition to the samples collected by the ESP, periodic small-boat trips were taken to the ESP mooring for collection of hand samples both to generate more material for analysis, and 'ground-truth' the ESP findings. The genetic analysis is ongoing, performed by our collaborators (Mary Ann Moran at U. Georgia, and Ron Keine, U. South Alabama), with results expected by the end of 2017. The biogeochemical data will be deposited at BCO-DMO on this website: http://www.bco-dmo.org/project/541255 The sequence data will be deposited in NCBI?s SRA (https://www.ncbi.nlm.nih.gov/bioproject) and iMicrobe (http://data.imicrobe.us/project/list) data repositories. Last Modified: 03/15/2017 Submitted by: James Birch