9633296 Sharp In recent years marine chemists have come to realize that dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) may account for a significant portion of the total organic carbon and nitrogen respectively in the marine environment. Even before this was known, these scientists also realized that identical seawater samples analyzed by different laboratories for DOC and DON often, if not usually, yield disparate results. In four previous years of NSF-sponsored research, the principal investigator established a seawater standard reference material and an interlaboratory cross-comparison for DOC. In this project, he will continue the very successful DOC seawater standards program at a reduced level and establish a similar standardization and intercalibration project for DON. This work is expected to help bring substandard analytical practices in some laboratories into line so that global DOC/DON datasets of high quality can be assembled for use in global-scale studies of (for example) marine carbon and nitrogen cycling and ocean chemistry-climate relationships.
