OCEAN ANIMALS
The open ocean, the largest environment on earth, has twice the surface area of all the land and the fresh water put together, and its average depth is 4 km.
The ancient environment has been remarkably stable until the last two decades of the 20th century.
This is shown in some detail in the ONEDIN module "Introduction to the Marine Environment".
Primary producers live in the epipelagic zone. They are plankton, tiny floating organisms.Plankton, that can perform photosynthesis, are called phytoplankton. Most are diatoms and dinoflagellates.