There are several new technologies being showcased in Finding Nemo Submarine Voyage.
The submarines are now electrically powered. The means of charging the batteries is through the track. It is a magnetic system that is symilar to the way a toothbrush recharges without metal components.
The plant "life" in the lagoon is painted with a new paint. The paint is composed of tiny pieces of colored glass. This is to help keep the props in the lagoon from fading due to the heavily chlorinated water.
Sets inside the show building are not all going to be submerged. Some of the new show scenes will be in an entirely dry environment. This will allow for the use of more sofisticated audio-animatronics and other equipement.
New projects will replace the use of Aduio-Animatronics. These projects will make it appear as if characters in the attractions are inside the water of the lagoon. This technology is currently in place at The Seas with Nemo and Friends at Epcot, and is very convincing.