Air Date: Week of September 16, 2011

British geologist Iain Stewart wants to demonstrate the symbiotic relationship between plants and people. So, he’s thinking outside the box and going in an airtight glass box for two days to live among 160 plants. He talks with host Bruce Gellerman about why he’s doing this experiment.

Transcript

GELLERMAN: It’s Living on Earth. I’m Bruce Gellerman. Scientists often try to think outside the box. But Professor Iain Stewart is definitely thinking inside the box. We called him up just as he was about to be sealed in a bedroom-sized container with a small forest worth of plants. Iain Stewart is a geologist and professor of geoscience communication at the University of Plymouth, England. Professor, welcome to Living on
Earth.

STEWART: Thank you. Thank you for having me.

GELLERMAN: Okay, so why seal yourself inside a box for two days? I mean, the
science is well known, what are you trying to prove?

STEWART: Well, I think everyone knows generally that the oxygen that we breathe
that’s in our atmosphere comes from photosynthesis and generally from plants, but, you
know, actually how much people appreciate that just how much of that oxygen, and how
much they rely on plants - that’s the kind of thing that they take for granted everyday.
You know, that’s a little bit more interesting.

And, from a scientific point of view, just how much photosynthesis you actually need to
get plants to produce the oxygen to keep an individual alive, well, you know, we’ve just
not done that. This little experiment is a metaphor for how much we’re relying on plants -
I guess that’s the key headline message we want to get across.

GELLERMAN: So, without plants, no oxygen. No oxygen, no people.

STEWART: Absolutely. You know, if we didn’t have plants, we would have a very, very different planet. And the point is - what’s lovely about this experiment is there's a symbiotic relationship in here - I’m in a box, a really small glass box, and basically I have to walk and exercise in order to give out carbon dioxide, to the plants that are around me in order for them to photosynthesize and give me back oxygen.

So, if I don’t do my job and I don't produce enough CO2, the plants can’t do their job and
supply me with oxygen. So, it just shows that really sensitive, intimate relationship we
have with vegetation that I think most ordinary people just aren’t aware of.

GELLERMAN: So, describe the box. How big is it? What’s it made of? Is it going to be
airtight?

STEWART: Well, the first thing is that I haven’t seen the box. I’ll be seeing it later this
afternoon. But I know the kind of dimensions of it and roughly. It’s going to be made
of a kind of glass, a glass perspex; it’s going to be see-through. It’s going to be airtight.

And the size - it’s, you know, a couple of meters across and tall, and about eight meters
long- stacked full of 150 or so small plants and maybe about 30 large plants - all of them
have been bred for the last few months to be efficient photosynthesizes.

There’s a huge theory here about how much these plants - how much oxygen they should
produce. But, the telling thing will be once we’re in there, and we've got the temperature
conditions, and my CO2 conditions, will be how much they actually produce. And, you
know, until we do it - over the next 48 hours - we really won’t know if that is going to
work out or not.

GELLERMAN: Well actually, it's going to be pretty cozy in there - eight meters is about
26 feet, I guess. So, you’re going to be very friendly with those plants! (LAUGHS)

STEWART: I’m going to be very friendly with those plants. And also, the center -
the Eden Center - where it's being held is it’s a tropical plant dome. It’s almost like the
Biome experiment that was running out of Arizona a few years ago - so then this place is
25 degrees Celsius.

GELLERMAN: Oooh. Very tropical.

STEWART: It’s going to be incredibly tropical, so I’m going… it’s going to be hot and
sweaty, surrounded by these plants. The other thing is, we have to keep the lights on,
constantly. So, it’s going to be daylight, essentially, for 40 hours - how the plants deal
with it, how I deal with it, is again, an uncertainty.

GELLERMAN: What about exercise, eating?

STEWART: Yeah, I mean, I’ve got an exercise bike in there, but that’s largely to do
experiment runs and know how my body’s reacting. But, also, crucially, to make sure
that I’m pumping out carbon dioxide for those plants. So I can’t just sit passively, and
you know, just kind of chill.

Um, in terms of food, I think it’s going to be salad. Because we can’t heat anything -
we can’t cook anything. So, I’m going to be surrounded by plants, and I’m going to be
eating them, which is a bit of an oddity.

GELLERMAN: What happens if you wind up having trouble breathing?

STEWART: The two potential health concerns are: the main one is how my body is
going to deal with the initial low oxygen. So, we're going to take oxygen down from

around 21 percent, which is normal, to about between 10 and 12 percent, which is
equivalent of an altitude of, you know, mountains, Andes, four and a half thousand
meters, five thousand meters.

You know, at that level, it’s very often that your body… you get dizzy, you get nauseous,
you get extreme headaches. So, it could well be that if it’s a very extreme reaction, then
we abort very early on - if I can’t handle the low oxygen.

GELLERMAN: Do you have a panic button?

STEWART: Uh, I think I can open from the inside, yeah. But, I’ll be monitored - the
idea is to monitor me - there’ll be doctors that are specialists in low oxygen there. And,
you know, the idea is to monitor me throughout. And, you know, the first and foremost
is my health and safety, so if we see it going awry, they’ll get me out of there.

GELLERMAN: Thank you very much, professor and good luck!

STEWART: Thank you very much. I’m going to enjoy it, I think!

GELLERMAN: Iain Stewart is a geologist and professor of geoscience communication
at the University of Plymouth, England.

 

Links

Iain Stewart’s Blog

The Eden Project