The problem with studying the deep ocean is that humans need light to look at things, the depths of the ocean are extremely dark, and what lives there is accustomed to spending most of its time in that darkness. So when we go down there with submersibles and turn on Big Lights to see, we invariably and dramatically alter what's going on, in the same way that it's generally difficult to observe the natural behaviors of terrestrial animals if you whip out a megaphone and shout HEY GUYS WHAT ARE YOU DOING at them first.

I put this in the comments but feel it needs a reblog- Check out some of Dr Edith Widder’s work on light in the deep sea! Among other things, she used the bioluminescence of stoplight fish to deduce wavelengths which most deep sea animals can’t perceive and used that to create light filters to be able to film with minimal disturbance! And that’s how we got 25 minutes of giant squid footage!!!!