Kinetic patterns in the transformation, cycle and formation of matter in natural water bodies are considered with Karelia as the example. We found that the transformation of organic substances, N_орг and Р_{общ, related to the assimilating capacity of the water bodies, proceeds at a much slower rate than the cycle of nitrogenous substances and productiondestruction processes. Labile organic matter was found to comprise carbohydrates, proteins, amino acids, and lipids.}