[ on-screen text ] This is a short film
about the people and places

of the Cuatro Ciénegas Basin
in Coahuila, México

The Cuatro Ciénegas Basin - its water
and microbial, plant

and animal communities -
are a treasure of México

All of this unique life has been uncovered

through the work of Mexican scientists
with international collaborations

This work makes possible

a deeper understanding of the history
of all of life on earth

My name is Valeria Souza.

I work as a researcher at UNAM -
the National University of Mexico,

that is a very large university.

This is probably the most important site
that we have in the world right now

to understand the origin of diversity.

This place has an amazing geology
that you can see just in front of you.

We have that kind of tsunami of rocks
that uplifted,

because the mountain
that is over that edge

is like an arrow.

It has an active fault
with magma underneath.

And, it's pushing all the marine sediments
that are from this valley up

and then it's flipped
and makes a heart shape -

a 3,000 meter mountain.

So, all this amazing geology
is an explanation of

why Cuatro Ciénegas is a singularity -

because these marine sediments

store the conditions of the ancient sea.

They store the magma...
that is rich in sulfur,

that takes us all the way back
to the Archean,

and it stores the minerals
that formed in sand.

These minerals are very old.

Also, it is a sediment that is devoid
of the most basic element for life,

that is, phosphorus.

So, this site is amazingly poor
in phosphorus,

and that makes for a very...
skewed stoichiometry.

Most of life now cannot live
in a skewed stoichiometry -

we need 60 nitrogens
for each phosphorus.

Here, we have 100 nitrogens - at least -
for each phosphorus,

in some places 200 nitrogens
for each phosphorus.

So, how they can make basic things,
such as ribosomes or DNA,

is because they are really good at
stealing phosphorus from anybody else,

including rocks.

So, they have an amazing array
of strategies

to deal with the lack of phosphorus,
and they did that since the Archean.

So, here we have stromatolites
and microbial mats,

whose ancestry goes back
to the Precambrian in some cases.

And, we are going to a site
where we think we have

the boundary between the Archean
and the Precambrian.

Since this is a blue pool,

we are talking about the moment
where animals turned the planet blue,

and that was in the Ediacaran
in the late Precambrian.

My name is Maria Kalambokidis,

and i'm an intern for a year,
working in Valeria's lab in UNAM,

in the Department
of Evolutionary Ecology.

And, right now, we're at Pozas Azules,
at the site of the Archaean domes.

So, here you have a microbial mat
that created a bubble

through the activity of the methanogens.

It created a bubble
and then it eventually burst,

creating this perimeter.

So, we sampled the microbial mats
that are still present there.

And, right now, they're hidden beneath
the salt crust,

because it's so dry.

My research is looking
at the evolutionary resilience

of the microbial mats
at Cuatro Ciénegas.

So, the microbial mats create
a codependent community

where each layer is sort of representing
the history of metabolisms on Earth.

So, you start with methanogens,

which create nutrients for the next layer
of sulfur-oxidizing bacteria,

all the way up until photosynthesis.

So, through this community,

they've become really dependent
on each other

and they evolve together,

creating a really resilient community
in Cuatro Ciénegas

that has existed for many millennia.

I was interested in the microbial mats

because they're evolutionary resilient
and they've existed so long here,

but also because they've existed
in an environment

that many other organisms couldn't exist.

For example,
a really low nutrient content,

in particular, low in phosphorus,

which is thought to be necessary
for the building blocks of life.

So, they've existed for so long,

they're able to exist
in extreme environments.

Therefore, it creates a sort of
living laboratory of organisms

that are alive today and indicative
of communities that existed long ago.

So, in origin of life research
and in astrobiology,

usually you're looking for signs of life -
like biosignatures on another planet,

or you're breaking open old rocks

to see if there are compounds
indicative of life.

But, in Cuatro Ciénegas,
and in these mats,

we think that we have the organisms
that formed the same communities...

that existed long ago.

So, as a biologist, it's really exciting

to actually be able to study it
alive today.

[ from Spanish ] The big questions
why so many species???

on planet Earth or in this place
???the history of survival???

The origin of life was probably very easy.

The origin of life was probably ??????
millions of ways possible???

On this planet, life survived???

???? the rocks
and transformed all of the minerals.???

My name is Gabriela Olmedo-Álvarez,
and I work at Cinvestav.

Cinvestav means:
"center of research for advanced studies."

I'm in Mexico,

right in the middle of Mexico -
in Irapuato.

I'm the director of Cinvestav in Irapuato,
although I am also a researcher.

And, I've been working for 15 years,
close to Valeria Souza,

in trying to decipher
what are the keys that allow

so much diversity of microorganisms
inhabit these places.

And, if you are looking at the pond
behind me -

that's a beautiful pond,
and it looks like it doesn't have much,

because it doesn't have
a lot of nutrients.

That is why it's so interesting -

it doesn't have nutrients,
but it has lots of different bacteria,

and has evidence of very old life.

It also has these stone-like things
that are stromatolites.

Stromatolites are evidence
of the first types of life on the planet,

but here they are still alive.

They are still, you know,
blooming,

and it's very interesting because
these are very, very old types of life.

And, that is possible
precisely because there are no nutrients.

So, other larger things
cannot compete with it,

and that allows these to remain
for centuries and millions of years.

But if we walk just a few meters away,
maybe just 200 meters,

we'll find a very different scenery.

We'll find these very salty crusts,

and these salty crusts
are full of life also -

a very special life
with lots of salt and with a low pH.

So, it's a weird life
that we do not understand,

and that's sort of one of the focuses
that we have for this trip -

to be able to sample
what things are living there.

And, we'll take them to the lab
to figure out

how some bacteria or <i>archaea</i> can live

with these very, very extreme
environments.

In the system called "Pozas Rojas,"

because these ponds
are fluctuating environments,

they get very saline in the summer
because the water evaporates.

It is deep water, not rain water,

so each one becomes a more vivid color
than in winter,

where water doesn't evaporate as much -

so they get like the juiciness
concentrated in the summer.

The life that lives here is very diverse -

there's microbial mass
that we have sequenced.

There's a very large biodiversity...
and there are like islands.

There are nine small islands
of these tiny pozas

and a big lagoon.

So, you can compare the diversity
in each one of them

separately and then...
the big poza in the middle.

But, this was perturbed
by a hurricane in 2010

and it became a complete lake,
all of its...

It kind of drained all the nutrients
and all the water

from the... east side of the valley.

The biology changed

because the pozas became connected
with the lake water,

and also the nutrients changed.

It was - before the hurricane -
it was the site with less phosphorus.

Now, it is a site that nearly has
a balance of stoichiometry.

So, it is very interesting how the life...

got habituated to this richer environment.

What is even more interesting is that
what was a very primitive...

site... it became a more Holocene site.

For example, the <i>Vibrio</i> that lives here,

they didn't radiate since the Holocene
in Cuatro Ciénegas,

which is at the same time as the fishes
came from the Río Bravo shelf.

So, they are very interesting,
and they are always changing,

and that makes us really happy -
and we are following their change.

So, I'm sure that the deep aquifer

still has the deep, ancient bacteria.

It shows that the lake that...

shaped here, that came here,

brought newer creatures from everywhere

that were bacteria more used to nutrients.

And, maybe there are pockets of nutrients
in different parts of the valley.

What makes Cuatro Ciénegas unique
is precisely the lack of nutrients.

Maybe they are going to become -
each time that we sample -

more and more imbalanced
and return to their ancient selves.

But, it will take time.

My name is Jorge Valdivia,
and I am a full-time professor

at the Universidad Nacional Autónoma
de México.

[...] of my doctoral studies
in the Cuatro Ciénegas valley.

I was working with the genus <i>bacillus</i>

and the project was focused on
knowing the relationship that existed

between the number of copies
of the ribosomal operon

and with the available phosphorus.

It is known that
the valley of Cuatro Ciénegas

is an extremely oligotrophic site.

With these conditions...
they are homologous

to what... the conditions in the past
[...] origin of life.

Then, the interesting thing
to find out was

how a genus that is characterized by

having many copies
of the ribosomal operon

can adapt to these conditions
of extreme oligotrophy.

We wanted to work in the isolates
of the main sites in the valley,

and we wanted to quantify
the genome level -

how many ribosomal operons they had.

We set them to grow
with water from the site

to replicate the natural conditions
in which they are found living,

and what we observe is that
there is a zero correlation

with respect to the hypothesis
of the growth rate.

A good indication are the viruses.

Viruses are the most ferocious hunters
in the world.

And, like ferocious hunters,
each one has their own favorite prey.

And, Cuatro Ciénegas is the most diverse
place on the planet for viruses

at the tiniest scale.

And, the favorite food of those viruses
are bacteria

My name is Nahui Medina,

and right now I'm a PhD student
in Nuevo León in Monterrey.

So, right now I'm doing this amazing
project about Archaeas and extremophiles.

What we do right now is try to isolate
every single microorganism that we can,

and we do this with amazing people
in the lab,

trying to create strategies

to make these microorganisms
live in the lab.

This is pretty much interesting because

Archaeas, you know, in Ancient Greek,
is about "ancient," you know...

This means that it could help us
to know how they lived

and try to understand...how life is...

what begun... at that moment...
it's pretty interesting...

They are so beautiful
because they have so many colors -

red, pink, and like a... yellowish,
some of them.

So, it's a pretty amazing project
we're doing right now.

Maybe because it's in a place where...

the whole ecosystem,
and the whole habitat is...

it's not in another place, you know...

you cannot find...
the species that are in here.

So, it's very... interesting

because the microorganisms
or the prokaryotes are living here.

There's just living here and that's it.

You cannot find them
in another place in the world.

So, that's what we're doing
and we're so happy to do it.

Here we are in Poza Azul Two,

that is one of the most beautiful pozas
in all the valley.

What we can see behind us
is a very big stromatolite shelf.

So, these blue pozas

take us back to 600 million years ago

when the animals changed the chemistry
of the ocean

and the ocean turned blue -

and that's called the Ediacaran Era.

So, in Cuatro Ciénegas,
we have kind of different timeframes -

different moments in geology
that got preserved.

And, that's really interesting
because it's not just a metaphor,

it's not just that it looks like...

the Ediacaran,
and when the ocean turned blue.

and still the stromatolite shelf
were being eaten by the first [embryos??]

[that was their due?]

But also, it's that this lineage
has survived -

survived for the longest time.

In the Archaean domes
that are 50 metres over there,

we have evidence that the Archaean -
a world of methane and CO2 -

is preserved inside domes
that are built by bacteria

that protect the ancient anaerobic
bacteria from the oxygen input,

while they are doing photosynthesis.

This kind of cooperation and construction
of the whole niche is pretty unique.

We know that stromatolite
were world-builders -

they made the ocean blue,

they transformed every element that came
from the start and made life complex.

For the fact is that,
here in Cuatro Ciénegas,

we have a window - a true window -
of those lost worlds is really incredible.

Because you walk... meters
and you find

three billion years... of time.

And, you can have lineages
that are very, very divergent

from the ones we know now,

how they assemble their nutrients
and how they work.

We can cultivate them,
we can study them using metagenomics.

But, for them to be studied,
we need water.

And, this water here is precious -
it's not just any water.

So, water that comes from that mountain
that has a magmatic heart,

that magmatic heart is responsible
for the Jurassic.

So, what happened is - humans -
we are really silly,

and we think we can manage nature.

When there's agriculture in the desert...

where the water comes comes from -
the deep aquifer.

And, it is not just any aquifer -

it's an aquifer that has stored
the conditions of the early sea,

and we are losing it.

Then we have the tragedy of Churince
where there's no longer water.

It only looks like that.

And now, it's a field
of dead turtles and dead fishes.

Maybe there's some hope
that we can recover it

if we close all the channels
that are taking out the water

from this ecosystem.