Photosynthesis In The Dark
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What is the main topic discussed in this episode?
We're here because your heightened awareness deserves heightened entertainment. The Last Show with David Cooper.
in a New Mexico cave. Microbes are doing photosynthesis in total darkness, which sounds impossible until it rewrites what we think life needs to survive. And then a conversation starts about where in the universe life might be hiding. We're here with someone who has researched this weird, wacky life. His name is Lars Behrendt. He's a microbial ecologist at Uppsala University and the Technical University of Denmark. Lars, welcome to the show. Thank you so much, David. You go to a cave, you shine a flashlight, and then you see it glowing green. What do you think?
What unusual microbes photosynthesize in the dark?
You think someone's down there playing around with glow-in-the-dark stuff, or you're on to something very strange in the world of biology?
Yeah, both, I think. So, I mean, I was really excited when you kind of can test your hypothesis as a scientist and suddenly you think you might have actually found something. So we went down into these caves based on some research that I did earlier in my PhD. And this was on, you know, kind of very special type of photosynthesis that we thought obscure. And we looked around different places and eventually we stumbled into caves. And yeah, there it was, lo and behold.
Look, I took biology in high school. I did badly in biology in university. When I hear photosynthesis in total darkness, I think that's a contradiction.
How do these microbes challenge our understanding of life?
Don't you need sunlight for photosynthesis?
Yeah, I think maybe what we need to define is a bit light, right? So typically we look at something called white light, which are, you know, specific wavelengths of light without boring you about the details. But there's a little bit of an extra in the red part that typically we as humans cannot perceive and see, yet it is actually used by bacteria to drive photosynthesis in these environments where We as humans cannot perceive light anymore, but they certainly can and they use it to survive.
So infrared light that this life is soaking up, turning into food for itself. It sounds almost science fiction. Tell me about how it works a little bit more technically.
Yeah, so, I mean, this is basically a discovery made 20, 25 years ago, which is a very special photopigment. So think chlorophyll, you know, what you also have in your average plant leaves that you look at when you look out the window. And this molecule has a slight modification to it and that actually allows it to harvest juice and take in the light of this very specific wavelength, which is kind of so-called the red shifted. And so another one of these chlorophylls has been discovered in 2010. And so it really expands now the range of the ability to drive photosynthesis in different environments. And so that excited us quite a bit. And of course, the field overall.
Let's talk different environments, because if we zoom out and we think of what life needs to actually live, that sounds weird, but I guess it makes sense. We start to think out in the cosmos. What can we learn from the life that you've discovered about possible life out there far away around exotic stars on exotic rocks and things like this?
What is the significance of finding life in extreme environments?
Yeah, so I mean, I think astrobiologists are quite excited about this because it ultimately might give us some hinters and pointers where to look a bit closer. So I think, you know, many of the other kind of planets and stars that we can observe often are are exposed to quite a lot of UV light. You might have heard about that. So you also get, as a human, if you're exposed to a lot of UV light, you get a sunburn. The same happens to bacteria. They ultimately can die if they're exposed to too much. And this is very, very hard radiation. So they basically die on the surface. So why not look below the surface, which obviously are caves? And so... Where do you do that? On Earth, in actual cave ecosystems on Earth.
So I think this is perhaps the closest analog, perhaps, we don't know, this is a hypothesis, to what might happen out in these other kind of planets that we have not yet discovered, but maybe where we should have a closer look about life.
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Chapters
5 chapters
1
What is the main topic discussed in this episode?
0:03–0:49
2
What unusual microbes photosynthesize in the dark?
0:49–1:31
3
How do these microbes challenge our understanding of life?
1:31–3:12
4
What is the significance of finding life in extreme environments?
3:12–7:12
5
How does light play a role in photosynthesis in darkness?
7:12–9:49
Speakers
3 identifiedMore from The Last Show with David Cooper
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