What term describes carbon-containing organic compounds dissolved in water?

• A. Dissolved Organic Nitrogen
• B. Dissolved Organic Carbon
• C. Ectothermic
• D. Energy

Answer: (B)

In aquatic chemistry, substances that are carbon-containing and organic but are dissolved in water are called dissolved organic carbon. The name itself signals three things: they are organic compounds (made of carbon), they contain carbon, and they’re in solution rather than as particles. These dissolved organic compounds come from the breakdown of plant and animal material and include substances like humic and fulvic acids, carbohydrates, amino acids, and other organic molecules. They’re typically measured as DOC, often in mg of carbon per liter, and they contrast with dissolved inorganic carbon pools (like CO2, bicarbonate) and with subsets such as dissolved organic nitrogen, which focuses on nitrogen-containing organics. The other options don’t describe a carbon-containing dissolved organic pool, so the best term is dissolved organic carbon.