Dissolved organic matter in streams and rivers can be broken down by sunlight or bacteria, providing a fuel source for aquatic ecosystems and affecting carbon dioxide and carbon monoxide concentrations as the organic matter is mineralized.
Researchers know that the amount of organic matter in streams fed by forest landscapes and those fed by watersheds affected by human activity, such as croplands, pasture, or urban environments, can differ greatly. What is less well known is how the organic matter from these various environments evolves as it flows downstream.