Why does iron fertilization of open oceans increase phytoplankton densities?

Explanation:

The iron fertilization is the method in which intentional introduction of the iron is done in the ocean. This is done in the area which has poor iron content.

This is important in order to increase the productivity or to accelerate the carbon dioxide sequestration from the atmosphere.

This is a trace element which is required for the process of photosynthesis in plants.

A large bloom of algae is developed using iron which will nourish the other members of the ocean.