It’s easy to think all our oxygen comes from trees on land – and a LOT of it does (especially rainforests, which there are lots of, and which need protection). But, in fact, most of it comes from the oceans.
That’s a bit harder to believe, but that doesn’t make it less true.
Plankton, specifically phytoplankton, produce most of the Earth’s oxygen. It also serves as food for sea creatures, but they don’t do much else that makes them interesting to most people. They just float around, completely at the mercy of the currents. They’re green and cruddy and you might even look at them and think “eww.”
And that’s fine since they also can’t be offended.
Here’s the deal: even though oceanic phytoplankton isn’t nearly as pretty as trees, it does similar work for us. These little organisms mostly float along the surface of the water or the upper part of the ocean where light still penetrates. They require sunlight to live and grow and produce food for other ocean creatures. They contain chlorophyll to capture the sunlight. If you remember back to grade school science, you probably see where this is going – photosynthesis.
Our oceanic phytoplankton turns the energy from sunlight, as well as carbon dioxide, and mineral salts partly into oxygen. There’s a lot of other stuff going on there too (other byproducts of photosynthesis, like the sugar they feed on), but oxygen is the byproduct we care about at the moment since we need it to breathe.
The cool thing is that even if you don’t live anywhere near an ocean, you still get the benefits because of the way the planet works. Oxygen is great because it just fills the atmosphere and doesn’t need to be shipped via trucks and planes to far-off destinations.
Scientists estimate that 50-80% of the oxygen production that takes place on Earth comes from the ocean. That’s a big range, but even if you go with the more conservative number, it’s clear that we can’t live without them. However, a lot of that oxygen also goes back into the ocean for other ocean life that needs it.
Don’t get us wrong, we love rainforests and regular trees too. But phytoplankton is doing more work than other flora when it comes to keeping breathing creatures alive.
We can do things like track plankton and get some readings off them, but it’s hard to know exact numbers of what they’re producing at any given time. The amount of oxygen they give off can change with the time of day or the time of year. It can also change depending on how healthy the oceans are.
One problem is that things like dead and decaying plants and animals in the ocean also consume oxygen when they decompose. That’s just one reason why killing off aquatic life (such as coral reefs) can be bad for us.
But if you remember one thing, it should be that these tiny, single-celled creatures do a lot of work for us by not only producing oxygen but by absorbing some of the CO2 we emit.
Some people call them “the lungs of the sea.” – WTF fun facts
Source: “How much oxygen comes from the ocean?” — National Oceanic and Atmospheric Administration