Hi. I am Dr. Kevin Bonine,

I'm Director of Education and Outreach at Biosphere 2.

And with me today is Dr. Joost Van Haren.

He's been doing research at Biosphere 2,

in the tropical rainforest for many years and he's going to tell us a little bit today

about what we've learned at

that rainforest and why there is exciting science that can be done there.

So thanks very much Joost,

I appreciate you sitting down with us.

Glad to be here.

So, I guess my first question,

what is so exciting to you about tropical rainforests?

So, tropical rainforests are exciting because

they are growing in areas that are almost ideal for biology to be active.

In the tropics, there's a lot of water,

the temperature is on an annual basis,

so continuously through the year it's relatively high.

And so it's perfect for trees,

and animal life to grow, and to be active.

And so these are some of the most active ecosystems that we have on our planet.

And so with that, to a disproportionate amount they actually affect how carbon,

water and nutrients cycle on the planet.

And so that's the main reason really to be interested in tropical forests.

So how are different parts of the globe connected?

And they find that indeed,

what happens to the tropical forest is really important not only for the Amazon basin,

not only for Brazil,

or Peru, or these countries there,

but it also can affect ecosystems here in North America for instance,

and different places on the earth.

Sure, I mean it's a big proportion of the terrestrial landscape that's

covered by tropical forests and as you said a lot of biological activity,

a lot of turnover, so it's going to have a big impact on atmospheric conditions.

And understanding something like Planet Earth Biosphere 1,

is challenging because you have this tremendous scale,

and you have all these interactions in different parts

of the planet interacting with other parts.

What is valuable and unique about the Tropical Rainforest of Biosphere 2,

and I know you work there, and you work in the Amazon, both places?

What's valuable about having

a controlled system under glass to help answer some of these questions?

So as some people say,

it's like we're doing experiment as humanity with Biosphere 1 of the Earth.

It's happening and right there,

it's an experiment where things are going on.

We actually are following it as it's developing over time,

but we have very little capability to control it,

or to make changes to it, or to see,

well if we do this which we think might happen in the future,

how are the forest going to respond?

Biosphere 2 helps us with that capability.

Most of the experiments that people have been doing are much smaller scale.

When they have those kind of questions they actually are looking at potted plants,

or they are looking at maybe a small little plot of forest,

where they then isolate it from

drought experiments that people have done where they covered part of the forest,

and then divert off the water.

Things like that have been done.

The Biosphere 2 is unique because it actually encloses

the whole ecosystem in a glass house.

Yes, so it sounds like you're able to work on a scale that allows you to

ask and answer questions that are more complex with more interacting components,

than you get with a single plant,

or on the lab bench,

where people have focused sometimes in the past.

But understanding how things are interrelated in a better way,

than if you were to go out into Biosphere 1,

where you don't know what all those variables are.

But inside Biosphere 2, you've got the soil,

you've got the vegetation,

you've got the atmosphere,

and you can manipulate all those things together and measure them all together.

So what are some of the key lessons that we've

learned from research inside the tropical rainforest in Biosphere 2?

So in the Biosphere 2 Rainforest,

actually the main overall lesson that we've learnt from the changes over time,

and how this rainforest has evolved,

is that, and this is because particularly this rainforest is growing in a greenhouse.

And what is a greenhouse, but some place where you actually trap to heat.

And it's a greenhouse in southern Arizona?

And it's located in southern Arizona,

so it actually does get quite hot.

So actually the Biosphere 2 Rainforest is the hottest rainforest,

or the rainforest that sees

the highest temperature of any rainforest on the planet right now.

So with that, with climate change,

it's projected that temperatures will increase in the future.

And so we have in a way, a window

on what's potentially the responses might be of the future forests.

And so what we see is actually that the resilience,

or the capability of the forests to respond to a certain pressure.

In this case, temperature is much greater than people give it right now credit for.

And that's partly because we haven't seen the trees,

and the plants in the real world respond to those kind of temperatures.

What's called plasticity, or the ability to

respond to temperature it is very large within trees,

and so they can actually really adjust and acclimate.

So what this leads to is that,

if we think again back to Biosphere 1, or the earth,

that this there will be a forest

still exactly what the composition of this forest is going to be,

is likely going to be different.

Exactly what it is that we don't know.

So the Biosphere 2 Tropical Rainforest is a model for helping us think

about how that kind of a system might respond to climate change.

And there's other kinds of models that people bring to bear to these kinds of questions,

and I know you've done some work with those,

and how they intersect with what we're seeing at Biosphere 2.

Do you want to say something about those models,

and what we've learned at that intersection?

Yeah. And that's also a way that we relate things and we also trying to,

because when we do our experiments,

when we do our measurements,

oftentimes they're in the air,

and what people really would like to know is how,

in the future are these forests going to respond and behave and so forth.

And how is their behavior going to affect the rest of the globe,

and so for that people have developed these mathematical models that are very complex.

They are called Land Surface Models

or Community Land Models is another term that people use for,

and they include both the atmosphere,

and the biological components.

And so what we can do

is actually take these models that people have used for the real world,

and try to understand how they interact with

the climate variables to bring them back to Biosphere 2.

Biosphere 2 is slightly a different condition,

situations set up, mild complexity and so forth.

So we can change the parameters that we know are different within the model,

and then while we can look at

the other parameters to see which ones that we have to change

to really capture the responses that we measure inside Biosphere 2.

And when we did that for actually carbon cycling,

specifically what we found is that the model that we took from the Amazon,

that we use for the Amazon basin that they can model the Amazon basin quite well,

we brought it to Biosphere 2 didn't function anymore.

And especially during the daytime,

late in the day it didn't model it quite correctly.

And what then turned out the parameters that we needed to change,

that actually was most predictive,

and had most of the adapted to model so that it actually

could model the Biosphere 2 data

well, was actually the temperature at which photosynthesis goes on.

We had to allow photosynthesis to go on,

at much higher temperatures than the original model for the Amazon basin did.

And so that suggests,

and comes back to what we talked about earlier,

that this is a forest that's acclimated to higher temperatures.

It can handle these temperatures.

It actually has shown a resilience in a way

of coping with the pressure

that we actually didn't both know was possible for tropical forests,

and so therefore the curve that temperature and photosynthesis

that was used in the real world was not realistic for Biosphere 2 and 1.

Being a part of that resilience,

and this goes back to what you said about the community composition,

you've lost a big chunk of the species that can handle these environmental conditions and

higher temperatures and so you now have

a response of a subset of species that you started with,

and maybe that is something that we need to consider in a place like the Amazon.

What's going to be the biodiversity going forward in the face of climate change.

Even if we do get a more resilient system than we thought it may not be as diverse,

and therefore perhaps less resilient to even greater changes.

And indeed, to delve more

in what are the really interesting differences between what we find in the Biosphere 2,

what we find in the real world,

and then trying to both marry those two models?

Can we make the models then be able to handle

both situations very well and give as much more confidence in the models?

But also mechanistically, can we understand better

what's going on in history by looking at two different systems?

There is a great untapped potential

there within the diversity for all kinds of things exactly here,

having spent a lot of time in the Amazon basin.

I know that the people who live there,

they make use of the resources,

and they have a lot of cures that

they bring out of the rainforest and some of these even have made it into being hired,

the building compounds for certain hutmans

and that we're using right now or cancer agents.

And it's super untapped resource.

And so it would be in that regard

it would be much more of a loss if the tropical forests would not be there.

And that's definitely something that we're looking

at whether is happening right now over the next decades,

maybe a couple hundred years from now.

It's a resource that's there,

beyond its own beauty and diversity,

it has capabilities that we really don't understand yet.

I think there's a lot of interesting things that we can use as a tool like Biosphere 2,

to address because we can make those perturbations,

we can tweak the system and look at what the responses are of those tweaks.

Exactly, and one of the things fine is with droughts we've

done is because Biosphere 2 is fantastic in

that regard you actually make a drought happen by just turning

a knob and you close a valve out and no more water.

You can take a sip right now,

but there's no more water that goes into the rainforest.

And so we can, very quickly and still over quite an intense drive to it.

Well, thank you very much.

We've been speaking with Dr. Joost Van Haren about the Biosphere 2,

tropical rainforest, and the research that's been done,

and the value of using our model system to understand how the planet works,

and how it might change in response to climate change. Thanks so much.

Lecture 5a - The Biosphere 2 Rainforest

Biosphere 2 Science for the Future of Our Planet

Meet the Instructors