What is the amount of light in the pacific ocean?

Answer 1

Depends on where you are in the ocean. Coastal water tends to be full of marine life, sediment, etc. that prevent light from reaching very deep. It also depends on the brightness of the light (obviously) but also the wavelength. Water absorbs longer wavelengths (green to red) quite well. Blues penetrate the deepest before being absorbed, which is why the water always looks blue when you're watching something that was filmed deep down. Coastal waters absorb greens and yellows the best, which is why they tend to look either teal or bright blue near the shore. Whether that's due just to different properties of the water itself (salinity, temperature, etc.) or the marine plants and such, I have no idea.

For those reasons (and the slightly more obvious reason of different times of day having different amounts of light), your question can't really be answered as asked. You would have to use averages from samples of ocean water to assign it an average opacity and go from there. According to NOAA, visible light decreases logarithmically at a rate of 90% per 75m, meaning at 75m you would have 10% of the light you would on the surface, then at 150m you would have 10% of that amount of light, which would be 1% of the light you had at the surface.