Ocean optics has been applied to study topics like primary production, phytoplankton, zooplankton, shallow-water habitats like seagrass beds and coral reefs, marine biogeochemistry, heating of the upper ocean, and carbon export to deep waters by way of the ocean biological pump. The portion of the electromagnetic spectrum usually involved in ocean optics is ultraviolet through infrared, about 300 nm to less than 2000 nm wavelengths.