So vast it is visible from space, the reef is actually built by tiny animals in partnership with microscopic plants.
Nitrogen and phosphorus are nutrients needed by microscopic plants called phytoplankton.
Shellfish are filter-feeders and live on a range of microscopic plants that float in the seawater.
The highest growth rates resulted when ultraviolet was completely filtered out of the sunlight reaching the microscopic plants.
The microscopic plant and animal world in ultraviolet light.
These microscopic plants are a major source of food in the ocean.
Before European settlers arrived, some scientists believe, the central role at the bottom of the food chain was filled primarily by phytoplankton, microscopic plants.
Plankton - microscopic plant and animal life drifting in the water - is humbler still.
The basic message is that these microscopic plants and animals are the basis of the food chain for all the lives in the ocean.
Another instrument measures how much light is available for microscopic plants to photosynthesize.