1. 1 2)In Libes chapters 22 and 23 as well as in the lecture slides many classes of organic compounds and organic functional groups are identified as being components of marine organic material. In theory any or all of these can be incorporated into humic materials becoming part of their structure or functionality. In the attached PowerPoint diagrams circle one example of each of the following structural entities: aromatic carboxylic acid group, aliphatic carboxylic acid group, aromatic ring, phenolic group, amine group, alcoholic group (aliphatic), branched and unsaturated hydrocarbon chain, polysaccharide, fatty acid, amino acid, metal complexation site, hydrogen bond, quinone. The functional groups can be circled using the circles provided on the right side of each of the PowerPoint slides. Just open the file in PowerPoint and position your cursor over the border of a circle. Click and hold the left mouse button and the circle will go into edit mode. With the mouse button still depressed you can move the circle to the desired location on the PowerPoint slide to highlight a structural feature. While in the edit mode the circles can be stretched to make ovals and resized to accurately encircle the structural feature of interest. Identify the features with a key based on slide number and circle color. Problem Set #3, April 13, 2004

2. 2 Morel & Hering, 1993 Branched and unsaturated hydrocarbon chain Alcoholic group Fatty acid group Aromatic ring

3. 3 Kleinhempel reprinted from Albrecht Thaer Archiv (1970) Aromatic carboxylic acid group Phenolic group Quinone Hydrogen bond Metal complexation Polysaccharide Amino Acid Amine Group Aromatic Ring Aliphatic carboxylic acid Alcoholic group carboxylic acid group

4. 4