The true colour of the Atlantic ocean is like the colour veridian. the thing about being in the middle of the ocean is there's no weird lights around, like from the city. When a wave crests all the light from the sun concentrates in the crest of the wave and it makes an amazing colour unlike anything else.

The water is bluey green because of algae, and sea water absorbs red light and reflects blue light. Even without algae it reflects blue.
The green colour is from the algae, of which there's many colours of algae including red, and brown, but this green colour mostly comes from green algae.