Small compared to Earth, the completed self-contained terrarium was
awesome at the human scale. Bio2 was a gigantic glass ark the size of an
airport hangar. Think of an inverted ocean liner whose hull is
transparent. The gigantic greenhouse was superairtight, sealed at the
bottom, too, with a stainless steel tray 25 feet under the soil to
prevent seepage of air from its basement. No gas, water, or matter could
enter or leave the ark. It was a stadium-size Ecosphere -- a big materially
closed and energetically open system -- but far more complex. Bio2 was the
second only to Biosphere 1 (the Earth) as largest closed vivisystem.
The challenge of creating a living system of any size is daunting.
Creating a living wonder at the scale of Bio2 could only be described as
an experiment in sustained chaos. The challenge included: Select a
couple of thousand parts of out of several billion possibilities, and
arrange them so that all the parts complemented and provided for each
other, so that the whole mixture was self-sustaining over time, and that
no single organism became dominant at the expense of others, so that the
whole aggregate kept all the constituents in constant motion, without
letting any ingredient become sequestered off to the side, while keeping
the entire level of activity and atmospheric gases elevated at the point
of perpetually almost-falling. Oh, and humans should be able to live,
eat, and drink within and from it.
SBV decided to stake the survival of Bio2 on the design tenet that an
extraordinarily diverse hodgepodge of living creatures would settle into
a unified stability. If it proved nothing else, the experiment would at
least shed some light on the almost universally held assumption in the
last two decades: that diversity ensures stability. It would also test
whether a certain level of complexity birthed self-sustainability.
As an architecture of maximum
diversity, the final Bio2 floor plan had seven biomes (biogeographical
habitats). Under the tallest part of the glass canopy, a rock-faced
concrete mountain bulged. Planted with transplanted tropical trees and a
misting system, the synthetic hill was transformed into a cloud forest -- a
high altitude rain forest. The cloud forest drained into an elevated hot
grassland (the size of a big patio, but stocked with waist-high wild
grasses). One edge of the rain forest stopped before a rocky cliff which
fell to a saltwater lagoon, complete with coral, colorful fishes, and
lobsters. The high savanna lowered into a lower, drier savanna, dark
with thorny, tangled thickets. This biome is called thornscrub and is
one of the most common of all habitats on Earth. In real life it is
nearly impenetrable to humans (and thus ignored), but in Bio2, it served
as a little hideaway for both wildlife and humans. The thicket leads
into a compact marshy wetland, the fifth biome, which finally emptied
into the lagoon. The low end of Bio2 was a desert, as big as a
gymnasium. Since it was pretty humid inside, the desert was planted with
fog desert plants from Baja California and South America. Off to one
side was the seventh biome -- an intensive agriculture and urban area where
eight Homo sapiens grew all their own food. Like Noah's place, animals
were aboard; some for meat, some for pets, and some on the loose:
lizards, fish, birds roaming about the wild parts. There were honey
bees, papaya trees, a beach, cable TV, a library, a gym, and a
The scale was stupendous. Once
while I was visiting the construction site, an 18-wheeler semi-truck
pulled up to the Bio2 office. The truck driver leaned out the window and
asked where they wanted their ocean. He'd been hauling a full truckload
of ocean salt and needed to unload it before dark. The office clerks
pointed down to a very large hole in the center of the project. That's
where Walter Adey from the Smithsonian Institution was building a
one-million-gallon ocean, coral reef, and lagoon. There was enough elbow
room in this gargantuan aquarium for all kinds of surprises to
Making an ocean is no cinch. Ask Gomez and the hobby saltwater
aquarists. Adey had grown an artificial self-regenerating coral reef
once before as a museum exhibit at the Smithsonian. But this one in Bio2
was huge; it had its own sandy beach. An expensive wave-making pump at
one end would supply the turbulence coral love. The same machine created
a half-meter tide on a lunar cycle.
The trucker unloaded the ocean: stacks of 50-pound bags of
Instant-Ocean, the same stuff you buy at tropical aquarium stores. A
starter solution harboring all the right microbeasties (sort of the
yeast for the dough) was later hauled in on a different truck from the
Pacific Ocean. Stir together well, and pour.
The ecologists building the
wilderness areas of Bio2 were of the school that says: soil + bugs =
ecology. To have the kind of tropical rainforest you want, you needed to
have the right kind of jungle dirt. And to get that in Arizona you had
to make it from scratch. Take a couple of bulldozer buckets of basalt, a
few of sand, and a few of clay. Sprinkle in the right microorganisms.
Mix in place. The underlying soils in each of the six wild biomes of
Bio2 were manufactured in this painstaking way. "The thing we didn't
realize at first," said Tony Burgess, "was that soils are alive. They
breathe as fast as you do. You have to treat soil as a living organism.
Ultimately it controls the biota."
Once you have soil, you can play Noah. Noah rounded up everything that
moved for his ark, but that certainly wasn't going to work here. The
designers of the Bio2 closed-system kept coming back to that most
exasperating but thrilling question: what species should Bio2 include?
No longer was it merely "Which organisms do we need to mirror the breath
of eight humans?" The dilemma was "Which organisms do we need to mirror
Gaia? Which combination of species would produce oxygen to breathe,
plants to eat, plants to feed the animals to eat (if any), and species
to support the food plants? How do we weave a self-supporting network
out of random organisms? How do we launch a coevolutionary circuit?"
Take almost any creature as an example. Most fruit requires insects to
pollinate it. So if you wanted blueberries in Bio2, you needed
honeybees. But in order to have honeybees around when the blueberries
are ready for pollination, you needed to provide the honeybees with
flowers for the rest of the season. But in order to supply sufficient
seasonal flowers to keep honeybees alive, there would be no room for
other kinds of plants. So, perhaps another type of pollinating bee would
work? You could use straw bees which can be supported with meager
amounts of flowers, but they don't pollinate blueberry blossoms or
several other fruits you wanted. How about moths? And so on down the
catalog of living creatures. Termites are necessary to decompose old
woody vegetation, but they were fond of eating the sealant around the
windows. What's a benign termite substitute that would get along with
the rest of the crowd?
"It's a sticky problem," said Peter Warshall, a consulting ecologist for
the project. "It's a pretty impossible job to pick 100 living things,
even from the same place, and put them together to make a 'wilderness'.
And here we're taking them from all over the world to mix together since
we have so many biomes."
To cobble together a synthetic biome, the half-dozen Bio2 ecologists sat
down at a table together and played this ultimate jigsaw puzzle. Each
scientist had expertise in either mammals, insects, birds, or plants.
But while they knew something about sedges and pond frogs, very little
of their knowledge was systematically accessible. Warshall sighed, "It
would have been nice if somewhere there was a database of all known
species listing their food and energy requirements, their habitat, their
waste products, their companion species, their breeding needs, etc., but
there isn't anything remotely like that. We know very little about even
common species. In fact, what this project shows is how little we know
about any species."
The burning question for the summer the biomes were designed was "Well,
how many moths does a bat really eat?" In the end, selecting the
thousand or so higher species came down to informed guesses and
biodiplomacy. Each ecologist wrote up a long lists of possible
candidates, including favorite species they thought would be the most
versatile and flexible. Their heads were full of conflicting
factors -- pluses and minuses, likes to be near this guy but can't stand
this one. The ecologists projected the competitiveness of rival
organisms. They bickered for water or sunlight rights. It was if they
were ambassadors protecting the territory of their species from
"I needed as much fruit as possible dropped from trees for my turtles to
eat," said Bio2 desert ecologist Tony Burgess, "but the turtles would
leave none for the fruit flies to breed on, which Warshall's
hummingbirds needed to eat. Should we have more trees for leftover
fruit, or use the space for bat habitat?"
So negotiations take place: If I can have this flower for the birds, you
can keep the bats. Occasionally the polite diplomacy reverted to open
subversion. The marsh-man wanted his pick of sawgrass, but Warshall
didn't like his choice because he felt the species was too aggressive
and would invade the dry land biome he was overseeing. In the end
Warshall capitulated to the marsh-man's choice, but added, half in jest,
"Oh, it doesn't make any difference because I'm just gonna plant taller
elephant grass to shade out your stuff, anyway." The marsh-man
retaliated by saying he was planting pine trees, taller than either.
Warshall promised with a hearty laugh to plant a defense border of guava
trees, which don't grow any taller, but grow much faster, staking out
the niche early.
Everything was connected to everything. It made planning a nightmare.
One approach the ecologists favored was building redundancy of pathways
into the food webs. With multiple foodchains in every web, if the sand
flies died off, then something else became second choice food for the
lizards. Rather than fight the dense tangle of interrelationships, they
exploited them. The key was to find organisms with as many alternative
roles as possible, so that if one didn't work out, it had another way or
two to complete somebody's loop.
"Designing a biome was an opportunity to think like God," recalled
Warshall. You, as a god, could create something by nothing. You could
create something -- some wonderful synthetic vibrant ecosystem -- but you had
no control over precisely what something emerged. All you could do was
gather all the parts and let them self-assemble into something that
worked. Walter Adey said, "Ecosystems in the wild are made up of
patches. You inject as many species as you can into the system and let
it decide what patch of species it wants to be in." Surrendering control
became one of the "Principles of Synthetic Ecology." Adey continued, "We
have to accept the fact that the amount of information contained in an
ecosystem far exceeds the amount contained in our heads. We are going to
fail if we only try things we can control and understand." The exact
details of an emerging Bio2 ecology, he warned, were beyond
But details counted. Eight human lives rested on the details fusing into
a whole. Tony Burgess, one of the Bio2 gods, ordered dune sand to be
trucked in for the desert biome because construction sand, the only kind
on hand at the Bio2 site, was too sharp for the land turtles; it cut
their feet. "You've got to take care of your turtles, so they can take
care of you," he said in a priestly way.
The number of free-roaming animals taking care of the system was pretty
thin for the first two years in Bio2 because there wasn't enough wild
food to support very many of them. Warshall almost didn't put any
monkeylike galagos from Africa in because he wasn't sure the young
acacia trees could produce enough gum to satisfy them. In the end he
released four galagos and stored a couple hundred pounds of emergency
monkeychow in the basement of the ark. Other wild animal occupants of
Bio2 included leopard tortoises, blue-tongued skinks ("because they are
generalists" -- not picky what they eat), various lizards, small finches,
and pygmy green hummingbirds, partially for pollination. "Most of the
species will be pygmy," Warshall told a Discover reporter before
closure, "because we really don't have that much space. In fact, ideally
we'd have pygmy people, too."
The animals didn't go in two by two. "You want to have a higher ratio of
females to males for reproduction insurance," Warshall told me. "Ideally
we like to have at minimum five females per three males. I know director
John Allen says that eight humans -- four female, four male -- is the
minimum-size group needed for human colony start-up and reproduction,
but from an ecologically correct rather than politically correct point
of view, the Bio2 crew should be five females and three males."
For the first time biologists were being forced by the riddle of
creating a biosphere to think like engineers: "Here is what we need,
what materials will do that job?" At the same time, the engineers on the
project were being forced to think like biologists: "That's not dirt,
that's a living organism!"
A stubborn problem for the designers of Bio2 was making rain for the
cloud forest. Rain is hard. The original plans optimistically called for
cooling coils at the peak of the 85-foot glass roof over the jungle
section. The coils would condense the jungle's moisture into gentle
drops descending from the celestial heights -- real artificial rain. Early
tests proved the drops to be scarce, too large and destructive when they
landed, and not at all the constant gentle mist the plants wanted.
Second plan was for the rain to be pumped up into sprinklers bolted to
the frame structure high overhead, but that proved to be a maintenance
nightmare since over a two-year period the fine-holed mist heads were
sure to need unclogging or replacements. The design they ended up with
was "rain" squirted from misting nozzles fitted on the ends of pipes
stationed here and there on the slopes.
One unexpected consequence of living in a small materially closed system
is that rather than water becoming precious, it's in virtual abundance.
In about one week 100 percent of the water is recycled, cleansed by
microbiological activity in wetland treatment areas. When you use more
water, it just goes around the loop a little faster.
Any field of life is a cloth woven with countless separate loops. The
loops of life -- the routes which materials, functions, and energy
follow -- double up, cross over and interweave as knots until it is
impossible to tell one thread from another. Only the larger pattern
knitted by the loops emerges. Each circle strengthens the others, until
the whole is hard to unravel.
That is not to say there will be no extinctions in a tightly wrapped
ecosystem. A certain extinction rate is essential for evolution. Walter
Adey had about 1 percent attrition rate in his previous partially closed
coral reef. He expected about a 30 to 40 percent drop-off in species
within the whole of Bio2 by the end of its first two-year run. (The
biologists from Yale University who are currently counting the species
after reopening have not finished their studies of species attrition as
of my writing).
But Adey believes that he already has learned how to grow diversity:
"What we are doing is cramming more species in than we expect to
survive. So the numbers drop. Particularly the insects and lower
organisms. Then, at the beginning of the next run we overstock it again,
injecting slightly different species -- our second guesses. What will
probably happen is that there will still be a large loss again, maybe
one quarter, but we reinject again next closure. Each time the numbers
of species will stabilize at a higher level than the first. The more
complex the system, the more species it can hold. We keep doing that,
building up the diversity. If you loaded up Biosphere 2 with all the
species it ends up with, it would collapse at the start." The huge glass
bottle is a diversity pump that grows complexity.
The Bio2 ecologists were left with the large question of how best to
jump start the initial variety, upon which further diverse growth would
be leveraged. This was very much related to the practical problem of how
to load all the animals onto the ark. How do you get 3,000
interdependent creatures into a cage, alive? Adey proposed moving an
entire natural biome into Bio2's relatively miniature space by
compressing it in the manner of a condensed book: selecting choice
highlights here and there, and fusing these bits into a sampler.
He selected a fine 30-mile stretch of a Florida Everglade mangrove swamp
and had it surveyed into a grid. Every half mile or so along the salt
gradient, a small cube (4-feet deep by 4-feet square) of mangrove roots
was dug out. The block of leafy branches, roots, mud, and piggybacking
barnacles was boxed and hauled ashore. The segments of the marsh, each
one tuned to a slightly different salt content with slightly different
microorganisms, were trucked to Arizona (after long negotiations with
very confused agricultural custom agents who thought "mangroves" were
While the chunks of everglades were waiting to be placed in the Bio2
marsh, the Bio2 workers hooked the watertight boxes up into a network of
pipes so that they became one distributed saltwater tide. Later the 30
or so cubes were reassembled into Bio2. Unboxed, the reconstituted marsh
takes up only a micro 90-by-30 feet. But within this volleyball
court-size everglade, each section harbors a gradually increasing
salt-loving mixture of microorganisms. Thus, the flow of life from
freshwater to brine is compressed into talking distance. The problem
with the analog method is that scale is an important dimension of an
ecosystem. As Warshall juggled the parts to manufacture a miniature
savanna, he shook his head: "At best we are putting about one-tenth the
variety of a system into Bio2. For the insect population it's more like
one-hundredth. In a West African savanna there are 35 species of worms.
At most we'll have three kinds. So the dilemma is: are we making a
savanna or a lawn? It's surely better than a lawn...but how much better
I don't know."