SOURCES AND REACTIVITIES OF MARINE-DERIVED ORGANIC-MATTER IN COASTAL SEDIMENTS AS DETERMINED BY ALKALINE CUO OXIDATION

Alkaline CuO oxidation of ubiquitous biochemicals such as proteins, po lysaccharides, and lipids, yields specific products, including fatty a cids, diacids, and carboxylated phenols. Oxidation of a variety of mar ine organisms, including macrophytes, phytoplankton, zooplankton, and bacteria, yields these CuO products in characteristic patterns that ca n often differentiate these biological sources. Sediments from Skan Ba y (Unalaska Island, Alaska) display organic carbon and total nitrogen profiles which are consistent with three kinetically distinct pools of organic matter. The CuO fingerprints of these sediments distinguish t hese three pools at the molecular level, indicating a highly labile, f atty acid-rich surface organic layer of likely bacterial origin, inter mediately reactive kelp debris and a background of phytoplankton remai ns that predominates at depth. The CuO method, which has been previous ly applied only to characterize cutin and lignin constituents of vascu lar land plants, also provides information on other types of abundant biochemicals, including those indicative of marine sources.