A submarine opening in karst formations where seawater flows or is drawn by a vacuum into the aquifer [20]. Synonyms: (French.) perte sous-marine; (German.) submariner Ponor; (Greek.) ypothalassia katavothra; (Italian.) inghiottitoio sottomarino; (Spanish.) sumidero marino; (Turkish.) denizalte suyutani; (Yugoslavian.) morska vodenica, morski ponor. See ponor.