Characterization of Biologically Produced Colored Dissolved Organic Matter in Seawater

: Colored dissolved organic matter (CDOM) is one of the principal light-attenuating components of seawater. Over the past decade considerable progress has been made in describing the optical properties of CDOM. However, our understanding of CDOM structure and chemistry has not advanced apace, and we do not yet understand many of the factors that introduce and remove CDOM in seawater. Our objectives are to chemically characterize CDOM and to develop techniques for studying CDOM cycling in seawater. Recent work suggests that a large fraction of marine DOM consists of complex carbohydrates and proteins that are produced directly from biosynthesis, yet are biologically refractory towards microbial degradation. Previous studies have also suggested that a large fraction of CDOM is associated with biological activity. We wish to determine if marine phytoplankton and bacteria produce significant quantities of CDOM, and to compare the chemical characteristics of biologically produced CDOM with CDOM in seawater.