that are formed by marine organisms. In addition, there are products of 

 in-situ chemical reactions and natural materials derived from atmospheric 

 sources. To an increasing degree, the sea contains residues of fossil 

 fuels and synthetic organic compounds. The organic components of 

 the marine environment interact with its other constituents through 

 continuous destruction, new synthesis, and exchange with the atmo- 

 sphere, the biosphere, and the lithosphere. 



We can now begin to describe partially the composition of organic 

 matter dissolved in seawater (DOM; 0.2 to 1.0 mg/liter), because of 

 recent advances in analytical techniques, such as the combination of 

 mass spectrometry with gas chromatography. The question of whether 

 or not DOM from various locations and depths is the same can now be 

 attacked. The bulk of this material may have a fairly simple structure, 

 but this seems unhkely. It has been suggested that DOM is a polymer- 

 like material condensed from amino acid and sugar subunits. Specific 

 research is needed to determine what soluble polymers exist in seawater. 



Dissolved organic matter requires more study for the following 

 reasons: 



• It is the largest reservoir of organic matter in the sea and one of 

 the largest on earth. 



• It probably modifies the chemical and biological properties of other 

 seawater components, especially the trace metals. 



• It may serve a function for marine organisms. 



• It may be of use to man (e.g., drugs from the sea). 



Regional studies of the organic chemistry of a few complex systems 

 can increase our understanding and allow us to advance to larger systems. 

 Intensive studies should be fruitful in oceanic areas where processes 

 are relatively more rapid, such as 



• Polar areas where the chemical character of water masses is con- 

 tinually changed. 



• Continental margins where biological processes and rapid sedi- 

 mentation help control the makeup of the sea. This includes upwelling 

 zones. 



A study of the organic matter in marine sediments that have been 

 deposited in the last one million years is needed. A chemical record of 

 how life adjusted to ice ages may be recorded in the proteins and amino 

 acids of carbonate shells, and the optical activity of these amino acids 

 may provide a new dating technique. Although amino acid levels in 

 carbonate depostis are low (~ 100 ppm), the analytical methods are 

 well developed (gas-liquid chromatography and ion exchange). Using 

 new colorimetric reagents, amino acids can be detected in seawater 

 directly. 



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