FT-ICR MS.xlsx

Marine phytoplankton are major source of labile organic matters in the upper ocean, and play critical roles in marine elemental cycling. However, the metabolism and transformation of phytoplankton-derived N- and S-containing organic compounds (e.g., GBT and DMSP) by heterotrophic bacteria is limited at the molecular level to date. The present study investigated microbial metabolites, community compositions/ secessions and microbial-DOM interactions with carbohydrate (glucose), N-containing (GBT) and S-containing (DMSP) substrates incubations. The substrate GBT support much higher bacterial growth rate and efficiency than the DMSP. Two humic-like fluorescent DOM components displayed environmental specific recalcitrant characteristic due to different microbial population successions in three substrates incubations. The median richness of microbial produced organic molecules (metabolites) was significantly higher in GBT than in DMSP incubations as revealed by FT-ICR MS result. The CHON and CHOS group molecules enriched in the GBT and DMSP incubations, respectively, suggesting elemental composition of substrates greatly influence the molecular composition of microbial metabolites.