There are a couple of almost bottomless holes of fresh water near Santa Rosa, New Mexico and there is rumors that the bodies of some who drowned in those holes were a long time later recovered from the Gulf of Mexico.
No refrences to post and I no longer remember who said it, but I did hear it once upon a time.
There is a fresh water lake near Pascagoula, Miss. with similar rumors. It rises and falls with the tides too.
Bottomless Lakes State Park, NM ?
http://www.lasr.net/pages/lake.php?Lake_ID=NM05lk001