S1E7: The Air We Breathe

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In this episode, Devon and Richard talk to Dr Julie Koester of UNC-Wilmington and Dr Orly Levithan of Rutgers about the truth behind where our oxygen comes from, and the tiny organisms we have to thank for our very existence.

Devon, here. For those of you who don’t know, which is probably most if not all of you, my background is in wildlife biology and a lot of work as a naturalist. But back in January of 2018, I decided to go back to school to work on getting my license to teach high school science. And that’s sort of how this weeks question–topic– came to be. I was in a high school classroom for a field experience when a student asked, “where does our air come from?” What she was meaning was our oxygen in particular. The teacher, trying to stay on topic, gave a quick answer and it was done, but it is an interesting question. Now, you may think it sounds silly—the answer is pretty clear, right? But what if I told you that answer —the one we all grew up with— is wrong. Or at least, not all the way right.

In this episode, we discuss how much of our air is actually made up of oxygen, how the oxygen gets there, examine whether or not the Amazon rainforest deserves all the credit, and give thanks to the tiny organisms (some made of glass, others of Tums) responsible for nearly half of the air we breathe.

As a visual aid, the featured photo is of on of these coccolithophore blooms mentioned during the episode. Below, you will find some images of diatoms as seen through an electron microscope (left) and immersed in oil seen through a light microscope (left).


Photo credit goes to Brook Hoffman who also makes some incredible handcrafted pens and candles at Wood & Fire!

Corrections and Clarifications

  1. Water is split to release the electron that travels the electron transport chain in a protein complex right at the beginning of the chain.  Chlorophyll and other pigments are a network, umbrella, around the electron transport chains that funnel the photons to that first protein complex (the major protein is D1).
  2. Silicon is the element, Si, silica == SiO2 silicon dioxide and it is the base for glass and diatom cell walls
  3. And 4. Go together: Algae are polyphyletic.  The term algae encompasses photosynthetic organisms from both the bacteria and eukaryotes.  It’s really all those photosynthetic organisms that are not plants.  We make a mistake at 22:47 with endosymbiosis and say that the upper levels of photosynthesis “are the algae”, when it should be “are the REST of the algae”.  Sorry about that!

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