Question

What are the three major ocean temperature zones ?

Answer 1

Surface zones would correspond to the latitudes:
Arctic, Temperate and Tropical.

Explanation:

Vertically they are separated by depth, which is ordered more by the amount of light than the temperature. There are no major divisions by temperature vertically beyond the initial thermocline.
http://marinebio.org/oceans/temperature/index.aspx

https://oceanservice.noaa.gov/education/pd/oceans_weather_climate/welcome.html

http://www.seasky.org/deep-sea/ocean-layers.html

http://ocean.si.edu/ocean-photos/zones-open-ocean

EXCELLENT d/l Chapter is available here:
https://sharkresearch.rsmas.miami.edu/assets/pdfs/learning-tools/high-school/MODULE%201%20Ocean%20and%20Coastal%20Habitat%20-%20SECTION%201%20Ocean%20Zones.pdf