In this study, we used Fourier transform ion cyclotron resonance mass spectrometry and excitation emission matrix fluorescence and parallel factor analysis to analyze molecular composition of solid phase extracted sediment-derived dissolved organic matter (SDOM). The transfomation of SDOM extracte by microbes was studied in its overlying seawater. Breifly, the SDOM extract was mixed into the seawater-filled carboys as SDOM treatments, while the no addition carboys were made as controls. During the 110-day incubation, bacterial abundance, viral abundance, total and dissolved organic carbon concentrations of the control and SDOM treatments were also measured.