This is the best I can do at the moment.
It's my daughter learning to dive at Portsea (Vic) about 4 years ago. She was 10 at the time. She is about 3-4 metres underwater and the photo was taken with a 2 or 3 MP Sony P&S in an underwater housing.
For those interested that is a Weedy Sea Dragon in the forground. It's a relation of the Sea horse.
Sorry I can't supply a nNikon DSLR underwater shot for you.