Snowfalcon2,
I really believe the "bluer light" to be an effect due to the water. I see no reason to use two different colors in the lighting apparatus. Phoenix International site only gives this information concerning the lighting system of the Remora 6000:
4 x Remote Ocean Systems 250 watt lights ( variable-intensity )
Actually, I have searched for other photos of the sea bottom taken from ROVīs. I couldnīt find many decent pictures, but the ones I found lack this effect. Please look at this one, from a submarine archeological site:
Woods Hole Oceanographic Institution(WHOI) : Archaeology in Deep Water
"Of course it's also entirely possible that, for example, there were some human remains on the seabed at that spot and BEA did not want to show those to the world."
Yes, I was considering this possibility the more likely, if this is really an alteration of the photo and not a natural effect.