Lake Cerknica is a periodically intermittent lake which may extend its surface up to 26 km(2) and reach 80 km(3) in volume. Lakes tend to age over time. Lake Cerknica does not possess properties of a real lake or those of usual wetlands thus making all of its physical, chemical, and biological processes unique. The feature with the greatest impact on plant development and animal life is the alternating nature of the lake where water from the lake is drained through the lake's bottom dries and refloods. Lake Cerknica was compared with a plant-based water treatment system and a sequential reactor with an approximately 6-month filling and emptying cycle. Lake Cerknica's basic processes of nutrient purification are the deposition of suspended nutrients on the lake bottom, integration of nutrients in plants, and partial denitrification.
Keywords: Karst; Nutrient purification; Periodically intermittent lake; Wetlands.