Workers on an oil platform filmed the strange light emanating from the seabed

[putnam6]

If it was near an oil platform, perhaps it was underwater welding for some pipelines?

Yeah I don't know one way or the other,

but if they were welding that far away from the platform wouldn't they be much deeper? that's why I'm thinking of gas bubbles and reflecting sunlight either through a patch of clouds or low on the horizon.