Being buried in blessed ground is the ideal. But if you are asking specifically about Catholic cemeteries then you should know that a plot in nearly any cemetery can be blessed. (The only reason I would imagine it couldn’t happen is because there is no priest who can bless the ground or for some reason the cemetery owner won’t permit it… I don’t know if deacons can bless the plot. I’d think so.)
I assume it works in a similar way for mausoleums. I don’t know the rules for burial at sea.