Dissolved, exchangeable and bound aliphatic amines in marine sediments: initial results

Abstract

Initial studies of aliphatic amines were undertaken to investigate the potential importance of these compounds in marine sediments. Marine sediments from a shallow bay on the coast of Massachusetts and from the continental margin of Mexico (Eastern Tropical North Pacific Ocean) were analyzed for shortchain aliphatic amines by gas chromatography with chemiluminescent detection. Two amines, dimethyl and trimethyl amine, were found in relatively large amounts, as much as 0.5% of the total organic nitrogen. Both amines were present in the interstitial waters, on exchangeable sites, and bound within the sediments. Similarities between amine and ammonia behavior suggest that, like ammonia, the amines are also a product of the decomposition of organic nitrogen compounds. Amines are more enriched in anoxic sediments compared to oxygenated sediments than would be expected from relative carbon and nitrogen contents. Amines like dimethyl and trimethyl amine may be important in reducing the C/N ration with depth in the sediment.