Two chemically distinct pools of organic nitrogen accumulate in the ocean.

Science

Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, CA 92093, USA.

Published: May 2005

AI Article Synopsis

  • The study investigates the chemical dynamics of marine dissolved organic nitrogen (DON), highlighting its complexity in areas limited by nitrogen productivity.
  • Half of the high-molecular-weight DON in surface waters consists of N-acetyl amino polysaccharides, indicating a different composition compared to deeper waters.
  • In the deep sea, the majority of high-molecular-weight DON contains amides that are resistant to chemical breakdown and biological degradation, pointing to distinct pools of nitrogen in the ocean.

Article Abstract

The chemical dynamics of marine dissolved organic nitrogen (DON), a reservoir featuring surface accumulations even in areas where nitrogen limits productivity, have yet to be resolved. We exploited differences in the acid lability of amide bonds within high-molecular-weight (HMW) DON to show that vertical DON profiles result in part from the presence of two chemically distinct pools of amide. Half of HMWDON in surface waters is present as N-acetyl amino polysaccharides. In contrast, nearly all deep-sea HMWDON, and therefore, most HMWDON, is present in amides that resist both chemical hydrolysis and biological degradation.

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http://dx.doi.org/10.1126/science.1108925DOI Listing

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