Organic material of recent Chesapeake Bay sediments

抄録

Samples of sediments at depths of 0∼10 and 50∼60cm from fresh water, brackish, and marine environments of the Chesapeake Bay were analyzed for n-fatty acids, n-alkanes, amino acids, lipids, humic substances, and total organic carbon and nitrogen. The abundance of n-fatty acids, humic substances, and total organic C and N was greatest in the fresh water environment and least in the marine. No similar trend was evident in the case of amino acids or hydrocarbons. The molecular distribution patterns of n-fatty acids and n-alkanes show maxima at a higher molecular range in the case of the fresh-water sediment and at a lower molecular range in the case of the marine sediment. The abundance of unsaturated n-fatty acids relative to that of saturated n-fatty acids decreases with sediment depth and also from the marine to the fresh-water sediment. Amino acids are readily recovered by acid hydrolysis. The distribution of individual acids in a sample is related to the chemical properties of the acids in the sediments. The concentration of lipids relative to that of humic substances appears to decrease with sediment depth. Samples of a recent oil spill in the neighborhood of the Bay exhibit a molecular distribution pattern different from those found in the Bay sediments.