Acylated heteropolysaccharides

DOM is also released into seawater by phytoplankton fiar reasons that are as yet imclear. On average, 13% of the phytoplankton carbon is released as exudates, some of which are low-molecular-weight compounds, such as free amino acids and tricarboxylic acids. Other exudates are high-molecular-weight compoimds, such as the acylated heteropolysaccharides. These macromolecules are relatively chemically resistant and appear to form a large portion of the HMW DOC pool. 

Heteropolysaccharides are complex carbohydrates composed of more than one kind of simple sugar. See Table 22.4 for the structure of the acyl functional group. 

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