Submarine or sea-shore opening in karst formations which at one season or period discharges ground water (fresh or brackish) from the aquifer into the sea-bed and at another season or period draws seawater into the aquifer by a vacuum [20]. Synonyms: (French.) estavelle marine; (German.) submarine Estavelle; (Greek.) estavelle thalassia (estavella); (Italian.) Estavella sottomarina, sorgente sottomarina a flusso alterno; (Spanish.) estavela marina; (Turkish.) sahil batar cikari.