More Influence for Underwater Cemetery

Delving deeper into my concept I have been thinking about how I could show an underwater forest and it just so happens such things exist! I really like the shapes in these forests but I feel my forest surrounding my clearing should feel old with wise thick trees and the idea of inter growth. I don't want the trees to look individual because I like the idea of unity surrounding the clearing.

In 20,000 Leagues Under the Sea Captain Nemo says...
"That is our peaceful cemetery, hundreds of feet below the surface of the waves."
"Beyond the reach of sharks-and-of men!"

So maybe there should be a feeling of a protective presence? Could these trees be tightly knit as if holding onto each other to prevent the entrance of trespassers?

It was quite hard searching for underwater clearings however, I did come across underwater meadows which were interesting and I think meadows are a good example of portraying peace so would make a good influence for this cemetery.

It was then on to the 'pedestal of rocks' and I found some really nice influence for the form of this. The coral cross that stands atop it however was something I thought would be quite difficult because I wasn't sure how coral could be manipulated to form a cross. I looked at minerals and semi-precious gemstones and actually came across this which I thought oozed peace and mourning but also had a fantasy element about it.

I also looked at lighting as I know this is going to play a key part in creating the atmosphere in my concepts. The lighting is also regulary mentioned in The Coral Kingdom chapter.
'The rays of our lights created something resembling a twilight, which lengthened immeasurably the shadows on the bed of the sea.'