Ocean colonization is when people live and work in the ocean, just like they do on land. Think of it like picking up and setting up a new home underneath the sea! Ocean colonies might be houses, stores, or even whole cities, and would be built with special tools so people could survive living underwater. People in ocean colonies could explore the vast ocean, learn about its creatures and plants, and find new ways to grow food. They could also build machines to help them explore areas of the ocean that are too deep for humans to dive. Ocean colonization would be like building a new world beneath the surface of the sea!