Combined amino acids in Pacific Ocean waters |
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| Authors: | Jeffrey L Bada Edward Hoopes Ming-shan Ho |
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| Institution: | Amino Acid Dating Laboratory, Scripps Institution of Oceanography, and Institute of Marine Resources, University of California at San Diego, La Jolla, CA 92093,U.S.A. |
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| Abstract: | Filtration and extraction indicate that the bulk of the combined amino acids in Pacific Ocean waters are a constituent of a dissolved component, and that they cannot be efficiently extracted from seawater by the macroreticular XAD-2 resin. In deep waters of the Pacific Ocean, alanine accounts for～60–70% of the combined amino acids, while in surface waters alanine makes up only～30% of the combined amino acid fraction. Serine is present in the combined fraction in surface waters, but is essentially absent in deep waters. These differences in the serine and alanine abundances between surface and deep waters are possibly the result of the dehydration of serine, which produces racemic alanine. Threonine can also undergo dehydration producing racemicα-amino-n-butyric acid, a non-biological amino acid which has been detected in deep waters of the Pacific Ocean. Estimates of the rate of serine and threonine dehydration in the oceans suggest that these reactions may have half-lives at 0°C of less than 100 years. As a consequence of dehydration, the dissolved organic material in which this diagenetic reaction has occurred may have reduced biological degradability. |
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