How come antarctic seas are more productive than most tropical seas?

Question

even though antarctic seas are colder and receive lower light intensity..?

Answer 1

Because oxygen and carbon dioxide both dissolve better at low temperature.  More carbon dioxide means more raw materials for plants and plankton to work with.  More oxygen means more air for everything (plants, animals, you name it).

Answer 2

I don't think they are.  Look at the vast wildlife differences.