This weeks episode of A Perfect Planet takes a closer look at the ocean, which, despite covering more than 70% of the earth’s surface is something many of us take for granted.

We often talk about deforestation being a crisis for our atmosphere; for the planets’ ability to turn carbon dioxide into oxygen, we and every other organism on the planet breathe. To be clear, it absolutely is a crisis, but here’s a fact that I learned this week: the ocean (or rather, the phytoplankton that lives within it) is responsible for as much as 80% of the oxygen we breathe.

The ocean is, in a word, a big deal. The continuing theme is of A Perfect Planet is the delicate balance that lets life thrive on Earth, and how we’re changing it. As the climate warms (and as we dump things into the ocean) the waters are becoming deoxygenated, impacting the cycles and lives we absolutely depend on. One of the more stunning images in this episode of whales in the Gulf of Thailand feeding. Where their prey used to live throughout the sea’s depths, deoxygenation means that there are fewer fish, and what fish there are stay near the surface. Now, rather than hunting, whales simply open their mouths and let the fish jump in.

This episode is full of the same kind of stunning images like this, the same kind that you are already accustomed to. Marine Iguanas in the Galapagos islands diving to eat seaweed, sharks having a feeding frenzy in shallow waters, and penguins hopping along rocks are all highlights. As before the episode functions as documentation of the amazing world we live on, which serves to both inspire awe and heartbreak as we barrel toward the climate changing beyond our ability to adapt and survive.

Next weeks episode focuses on another big influence on the planet: us. In previous series when the cameras have been turned toward us the result has been just as –if not more– fascinating as when they’re pointed at the rest of the world.

Other Thoughts:

• 14,000 tons of freshwater is melting into the oceans each day. Holy shit.
• Phytoplankton being responsible for up to 80% of the air recycling in the world means that they are responsible for more than all the forests in the world combined. Holy shit.
• Whales adapting their feeding patterns to the point where they just open their mouths and let fish jump in is adorable, but also kind of harrowing when you consider why it’s happening.

A Perfect Planet Reviews:

1. Episode One: Volcanoes
2. Episode Two: The Sun
3. Episode Three: Weather
4. Episode Four: Oceans
5. Episode Five: Humans

A Perfect Planet episode four: Oceans‘ premieres today, January 24th, on BBC Earth at 8 pm eastern/pacific.

Photography copyright Ed Charles / Silverback Films