I happen to have a daughter that not only loves dinosaurs, but the ocean as well. And as much as she loves the entirety of it, she is most fascinated by the very deep parts. I think a lot of it started with The Blue Planet series, especially the Open Ocean/The Deep.
Isn't that a great image on the cover. We watched it on Netflix instant and she wanted to know more. The next time we went to the library, we checked out a bunch of books and this one was a family favorite