Why do we send humans to those depths rather than a camera? I assume signal to control the camera is hard at those depths but that is the only reason I can imagine.

The water pressure at 9km deep is about 900 atm!

  > 900 atm!

It seems a shame to wonder if deep sea worms and molluscs will become the next headline meal at Hong Kong's high end Cantonese seafood restaurants: no doubt like everything else they go well with oyster sauce and finely cut ginger.