A headline about the ocean producing oxygen can sound as though every bit of that production simply accumulates in the atmosphere. Marine life also uses oxygen, which makes the balance more interesting.
Keep production and consumption together
NOAA estimates that roughly half of Earth’s oxygen production comes from the ocean and explains that marine life consumes about the same amount. Its ocean oxygen overview connects production by photosynthetic organisms with oxygen use in marine processes.
The estimate is not a claim that a particular patch of water produces half the air around you. Nor can it identify the source of an individual breath.
Read the scale of the statement
When sharing the idea, preserve words such as production and estimate. Ask whether a number describes a global process, a local measurement or oxygen dissolved in water. Those are related subjects, but their quantities are not interchangeable.
A useful notebook sketch has arrows for both production and consumption instead of a single arrow out of the sea. It reminds you that an ecosystem is active on both sides of the balance and keeps a striking fact connected to the processes that give it meaning.