9503487 ARNOSTI The rates at which organic macromolecules are mineralized, and variations in degradation rates with location, depth, and season are critical aspects in calculating the turnover rates of oceanic organic carbon. Recent studies have suggested that large dissolved polymers, particularly polysaccharides, may be rapidly cycled within the upper ocean. There are currently few methods, however, to directly measure the hydrolysis of organic macromolecules in marine environments. The objective of this pilot project is to test and apply a new method to measure hydrolysis rates of polysaccharides in marine environments. The method is based on synthesis of fluorescent-labeled polysaccharides (FLA- polysaccharides) which can be added to seawater or sediments. Enzymatic hydrolysis of FLA-polysaccharides yields labeled fragments of lower molecular weight. The molecular weight changes of FLA-polysaccharide are determined using gel permeation chromatography. The end result is a profile showing changes in FLA- polysaccharides molecular weight vs. time.
