(The Science of... theme music)
(cheering)
- Last time they handed me a mic,
I told a chemistry joke but there was no reaction.
(laughing, groaning in fun)
No, it's okay, I'm only up here telling bad chemistry
jokes because all the good ones Ar-gon.
- So there's an entire science of food forensics.
I can tell you if your Florida
natural orange juice is from Florida.
I can tell you if your shrimp is actually Mayport Shrimp
or if it was grown in a pen off of the Vietnamese coast.
So first, I wanna say that, so a lot of the research you're
gonna see is a collaboration of a number of researchers.
So I've worked with some great research groups
in my degrees, and on my projects,
and some of the stuff we'll be seeing tonight
was actually funded by the Department of Defense,
the CIA, and the FBI, creepy, right?
So we'll talk about sorta some things about water,
and water security, which is becoming,
especially if you've been watching the California fires,
right, so water is becoming very important.
So we're gonna talk a little bit about that.
Let's talk about isotopes real quick.
I promise this chemistry part will be sort of mellow.
Alright, so just to remind you what an isotope is,
it's not a baseball team in The Simpsons,
though actually it is a baseball team in The Simpsons.
And I have that t-shirt, too.
It is an element that behaves chemically the same as
everything else as that element, but it's a little bigger.
Its mass is a little bit bigger, so you could have
heavy isotopes and you have light isotopes.
Right, and they behave differently in nature.
So, they tend to collect in certain areas,
you'll have more heavy isotope in some things
and you'll have less heavy isotope in other things.
So, what we're focusing on, there are
lots of different elements that have isotopes.
We're gonna focus on the light isotopes,
the stable light isotopes is what we call them.
Hydrogen, carbon, nitrogen, and oxygen.
So these are the ones that we focus on
because they're part of our natural systems,
so all of you are made up of hydrogen, nitrogen,
oxygen, and what did I miss, carbon, lots of carbon.
You are carbon-based, right.
So those are the big ones, and they tell us something
about nature: how it functions, how it behaves.
We watch how these isotopes sort of change in nature,
and that tells us something about the processes.
So, they create these fingerprints,
and we're gonna see some of these fingerprints.
We're in a brewery, let's talk about beer.
There is an ingenious group of scientists that got together
and studied the isotopes of beer, because why not, right?
So they found some really interesting things.
I mean, it's not just for fun.
On the left, on this top plot, we have two sort of
pyramids, right, so these are two statistical plots.
And we have two kinds of plants.
Right, we have C3 plants and C4 plants,
without boring you too much, C3 plants came first,
they evolved first, C4 plants came next.
And they photosynthesize a little differently.
Well that's good for us because it creates sort of
different structures in plants, in their sugars.
What we see here, these C3 plants, why we care about beer.
We make beer out of sugars, right?
So there's barley, which is common if you're German, right.
There's a purity law, you make beer
out of hops, barley, and water, right.
Anywhere else you can make it out of
whatever sugar you can find, right.
So, on this plot, on the right-hand side,
if we're looking at, in the right-hand side is corn.
And on the other, sugar, cane sugar, they're both C4s.
C3s are barley, right so, there's a difference here.
And there's an isotopic difference.
So this group went out and bought beer, all kinds of beer,
and ran the beer for isotopes.
They ran the carbon in the beer.
What they found were this distinct
pyramid sort of on the bottom.
Now these U.S. and Canadian beers sort of lean
towards the barley side, with some corn.
Now, if you go down to these foreign beers,
the expensive ones on the menu, right,
we have sorta two groups: we've got European beers,
which are almost completely dominated by C3,
and then we have these other, New World beers,
right, which are dominated by C4.
Alright, so yay, we make beer in Europe out of barley,
we make beer in Brazil out of cane sugar.
So why does this matter?
There's a distinction in price, right.
So they saw a correlation between how much C4
was in the beer and how much it cost.
So you put more barley in a beer, it costs more.
You put more sugar, cane sugar and corn
in a beer, it costs less.
So why is this, we can start, and then they went into this
great discussion about why it was more expensive
to make sugar beer versus barley beer.
Barley's a little more expensive in the ingredients side.
Right so, it takes a little bit more to malt,
to make it sugary, and to make beer out of it,
kinda makes sense that it's a little more expensive.
In Brazil, cane sugar floweth freely, right.
So you make Coronas and other beers out of
cane sugar because it's cheap, right.
And there's also the fact that it ferments
a little bit faster, so you can make more beer faster, so
there's this link between this cool isotopic world and beer.
We can also think, if you pull up a bottle of super
expensive imported German beer, and you run the isotopes on
it, and it falls in the C4 land, you have an illicit beer.
So there's an entire science of food forensics.
I can tell you if your Florida
natural orange juice is from Florida.
I can tell you if your shrimp is actually Mayport Shrimp
or if it was grown in a pen off of the Vietnamese coast.
Right, so these fingerprints make their way into our food,
and our water, and this is just one example.
So all of you who are enjoying a libation tonight
are busy consuming those isotopes.
And what your belly's gonna do is then transform
that food and water into body parts, right,
your blood, your skin, your hair.
That signal is gonna make its way into your body.
So how do we apply this to migrations?
What I was interested in, this was
interesting, but this was not my work.
What we wanted to know was about water.
We know isotopes change as rain changes.
So the closer you are to the rain source,
the less isotope, the less heavy the isotope you have.
Right, so as you move up mountains, you concentrate
lighter and lighter isotopes.
Right, so what you end up with is a map like this.
So this is an isotope map of the United States.
This is what the precipitation
comes out, I believe in hydrogen.
Right, so the rain falling on our heads
has a very distinct signature.
This is all the maps of rivers
and lakes in the United States.
And what the isotope value of those lakes and rivers are.
So the river flowing, the St. John is flowing past us,
we can go down here and we can figure out
what the isotope value is at that.
So what that tells us is what the
local water source looks like.
So what does the water you drink, what is the water
that goes in the food you drink, your coffee,
your orange juice, your Coca-Cola, your beer, right,
all has that isotope value.
So if you're from Colorado, you're gonna be bluer.
If you're from Florida, you're gonna have this oranger,
or heavier isotope signature.
So, why is this interesting?
Well, we can start to figure out where
you're from by the water in your body.
So, how do we do that?
You are what you eat and drink, right?
So if we look at this, your isotope values are
in all of your different fluids.
Right, the vapor that's coming out of your mouth right now
has a very specific isotope value.
And I can sorta tell where you're from
by just looking at the isotopes in your vapor.
However, we overturn our body water every seven days.
You do it a little faster if you're a crazy athlete,
you'll do it in like three or four days,
or strangely enough, if you have diabetes,
you also overturn your water much faster.
So this is a way of detecting diabetes in some way.
But, what it means is, every seven days,
you'll switch your water over.
So if you go to Colorado and start drinking water and coffee
and juice, you'll start to have a Colorado signature.
At least in your body water.
However, there are things that grow much slower, right?
Your fingernails, your hair, your skin, grows slower.
Right, and those of you with long hair in the room,
you've got a great record of your
isotopic geolocation, where you've been.
Alright, so how do we do this?
Well, your ratio is made up of what you drink,
what you eat, and what you breathe in.
Alright, so two of these we can get rid of.
What you breathe, we're all breathing the same atmosphere
really, so it doesn't matter if you're in San Francisco
or if you're in New York, or if you're in the Himalayas.
Basically, the air you breathe has an isotope signature.
So we don't have to pay attention to that.
The food we eat, strangely enough, is very national.
We have a national signature of food,
because the brussel sprouts you're eating are from
California, and the tomatoes are from South Florida,
and the beef is from Indiana, right.
So all this food goes together and we ran around,
someone ran McDonald's meals,
and figured out there were five isotopes signatures
for beef in the country, right,
'cause there were five major areas where cows come from.
Right, so that food, we can sorta take that out
'cause it doesn't vary that much.
We all eat in this sorta global supermarket.
So that leaves us with what you drink, right,
so that's what led us to this aha, we can figure out
something about your location by looking at water.
So we found out this is really true.
Your hair is related to your water.
So there's tap water signals on the left,
and the hair on the right, they correlate very well.
So the change in tap water correlates
excellently with your hair.
So we can do a very good job of figuring out
your tap water source from your hair.
Alright, and if we go on a little bit further,
they ran someone's long hair who just moved from Beijing
to Utah, and they did segments of her hair.
Right, and what they figured out is they watched her hair
from the tip, right, which was Beijing,
all the way to the scalp, which was Utah, and they
could watch you equilibrate to your new environment.
Right, so they could watch your isotope signature
change as you went to a new place.
So, you know, and this is the CIA and FBI, right?
What are they interested in, where have you been?
So shave your hair off if you
don't want them to know, right?
So this also works on your fingernails.
Unfortunately it's in your teeth, that's kinda scary, right?
But, this is interesting, the FBI doesn't care about
where you've been, when they find a body with no teeth,
right, and no identification, where is this body from,
or what they often find is a body that's badly decomposed,
right, this is also the kinda
creepy part of this post-doc I did.
They have to find out where that body was from.
We have this probabilistic model, right.
We know what the isotopes are,
we can guess where you're from.
So, if you have an isotope signature on the top signal
it's great, we can just look in these places.
'Cause if you've been living there
for long enough, you've got that signature.
So we can look for missing persons in that area.
If you've got a different isotope signature, you know,
the mountain west, there's a little bit wider area,
but we can still kinda figure out where you're from.
Alright, but here's the problem,
and it goes to this sort of idea.
Water is not everywhere, right?
There are areas of water scarcity.
This is a map of water scarcity.
It's also a map of water security.
So where you see reds are areas that are highly stressed,
right, there's not enough water for the need in that area.
We looked at these hot spots, and we figured, well, okay,
the people don't not live there, right,
so people live in the Southwest United States,
a lot of people live in Los Angeles, but there's
not enough water in Los Angeles for those people.
Go to Las Vegas, not enough water.
So what do they do?
Yeah, you import the water, right.
So that works, but the problem is,
if you're a forensic isogeochemist,
you're screwing up my model, right.
You're drinking water from Colorado,
but you live in Los Angeles.
So if you go missing, and not like people go missing
in Las Vegas or Los Angeles, right?
If you go missing, maybe your
signature's not gonna be right.
So we went into this, and we're like okay, can we tell
how much water's being imported by looking at the isotopes.
So we went to our closest model, we went to the Southwest.
And we have all of these different sources of water,
and I was gonna kinda fly through these.
If you know these, all these aqueducts feed Los Angeles.
So there's the Los Angeles Aqueduct, there's the
California Aqueduct, and the Colorado River Aqueduct.
All of these feed into Arizona, Las Vegas, and Los Angeles.
Right, so we're feeding all this Colorado water,
or water from San Francisco, into these places.
Right, so I drove around and put 6,000 miles
on my rental car from Las Vegas, that was hilarious.
You leave, and you come back, and they scan it,
and they look at you like this, but it's unlimited mileage.
Right, so I used my unlimited mileage,
I bottomed out a Volkswagen Jetta on the border of Mexico,
driving down a road, I've been pulled over by the border
police, you can see I did all these ones along the border,
and if you've ever not driven that border, you should.
A lot of it is just nothing, desert, right.
And I would drive back and forth looking for this
thing on the map that was a gas station,
'cause they have a water tap, right,
I wanted their water sample, so you drive past
Border Patrol three times, they get suspicious.
And they pull you over, and you've got all these
little bottles of water in the back of your car,
and you've got a story, and you're like I'm doing science,
right, it usually got me out, I had to get radioed in
a few times, but it was an interesting trip, right.
So, water samples, literally walking in the backs
of McDonald's, you start to figure out there are like
three models for McDonald's in the Southwest,
and some of 'em are easy to sneak into in the bathroom,
some of them you have to walk awkwardly through, right,
just to get a tap water sample.
But on top of that, we took 20 hair
samples, and 12 alfalfa samples.
The hair samples are the most awkward,
'cause you wander into your average barber shop,
right, and you ask, can I sweep some hair off the floor?
I'm doing science, for who, the FBI.
Right, no, you say you're doing it for a university.
Usually they were pretty cool with it,
some people gave you the dirty look
'cause they were getting their hair cut, right,
so that was the stuff on the floor.
But what I wanna know is the hair,
is that signal making it into the hair?
I wanted to know if it was moving up that food chain,
from the alfalfa, that goes into the cows,
and the cows that go into us, right.
So, I did some research, and you start figuring out
exactly how these cities do water, it is remarkable.
They spend a lot of money on water.
Just an example, the city of Los Angeles,
you can see it gets a third of it from the aqueduct,
a third from what we called CRAQ water,
which is the California Aqueduct.
It become a joke in the lab, you know,
we're running more crates of CRAQ from Los Angeles.
And then local groundwater, which strangely enough,
they recharge the local groundwater with aqueduct water.
So they have recharge areas where they pump the water
into the ground, and pump it back out.
It is not a joke that when you drink a glass of water
in Los Angeles, it's probably been through
three other people before it went into your glass.
Alright, so what do we do with that?
We can take our model, and we can figure out
what your local source is, right.
What should the local water look like,
versus what do we actually see.
And we came up with this model of how much water
they were pumping in, from this isotope signal.
So you can sorta look, if it's these darker blues,
those are pumping in, almost all the water
is being brought into the city, into that tap water system.
If they're white, almost none.
Right, so it's varied, and it's all sorts of politics.
You wanna talk about Spanish water
laws, they're crazy out there.
How much you can draw, from where you can draw,
from when you can draw, and how much money you have.
So, population density, how much money you have,
access, agricultural demand, all these things
go into how much of this imported water makes it
into that tap water system, which then makes it into you.
Okay, so we tested our model, and it was pretty good.
We actually were pretty happy with most of these results.
There are a few weird ones, like Palm Desert,
that didn't fall in, you gotta figure out
what they're pumping into the water system in Palm Desert.
Something else is happening, R.O. water sometimes.
So reverse osmosis water makes its
way in, that's got a weird signal.
But from our model's stance, we were pretty good.
We could figure out how much water was being imported.
This is a map of that river, with those hair samples
overlaid on it, so we added all the samples we had together,
and for the most part, people look like where they're from.
So you notice in the blue areas, there's lots of blue.
There are a few weird spots, right.
We can tell the people who weren't from that area.
So that yellow dot in Salt Lake City was someone from Texas,
who was studying at the University of Utah.
We could see it in their hair.
However, these dots down here in Los Angeles,
those are the ones that I added, the ones over in Phoenix.
They're blue dots where it should be yellow.
Which means they look like Colorado water.
Right, so their forensic values are not
gonna fall into that probability model.
We have to alter the model.
So if you find a missing persons with that high, light
value, that blue value, you have to look beyond
where they are and look into missing persons reports
in Los Angeles, in Phoenix, in Las Vegas,
'cause those people could be from those areas.
Right, so this is what the FBI's interest.
The CIA never really told me what their interest was.
If you want interesting stories, I'll sit down with you
with a beer and talk about how that was.
I had lots of emails with first, people with one name.
I went to a conference where everybody was like Bob, Nancy.
Right, your name's not Nancy.
It was kind of odd, but you learned all sorts of
really cool stuff, and presented your data.
So, what have I done with this?
I'm not snipping hair anymore.
A lot of my students are interested
in charismatic macrofauna, right.
So animals, I can use them to get at the water, right.
You are recording right now where you're from.
So if all of you go on a European backpacking vacation
for three weeks, right, 'cause we all about to go do that,
you're gonna record that signal all through your hair,
and we can find out where, roughly,
you've been, right, by looking at that.
Well, turtles do it, too, right.
So we know they're turtles, this left-hand map
is that same isotope map, right,
so those are isotopes in the ocean of carbon.
So if you're from this Southern part,
you're hanging out in Cuba, you have a different signal
than if you hang out in North Carolina.
And we've got turtles that come from both
Southern waters and from North Carolina.
So one of my students went out and she collected eggshells
from nests, after they'd hatched, so the babies were gone,
and ran them for isotopes, right.
So we have these two groups of turtles, right,
that are coming from the South, and coming from the North,
and ending up on our beach at the same time,
making baby turtles, or they've already made
baby turtles, they're depositing baby turtles, right.
But we can figure out that migration pattern, right.
We have turtles that are coming from
as far as Cuba, all the way up here.
We can do this with anything that collects isotopes.
Ivory is a big one, we can tell where ivory is coming from.
If it's illegal, and seized, we can tell if it's
elephants from the South, or the North,
are they from Tanzania, are they from Kenya.
They have different signals.
So these approaches have all sorts of uses,
and we're just figuring out some of these systems.
So we're just answering questions now.
But we have all sorts of other questions, like
what happens when you live in Los Angeles,
but are drinking Colorado water?
What happens if you're an elephant that, you know,
hangs out in Tanzania, but only eats when you're in Kenya?
That hasn't happened yet, but it could.
So, I invite you to use your imaginations,
ask me any sort of questions you want,
'cause these things are used in all sorts of systems.
And then finally, think about what your ratio is.
What is your hair gonna say?
Alright, if you've been living somewhere else,
and your hair is long, you might have
that signal still in your hair, right,
or in your nails, fingernails, your teeth.
These are places we keep these.
And then, what they're doing with this,
well, I'm not sure anymore, 'cause I don't
work for the CIA, right, anymore, so,
they can use this, and I don't think we're
that far away from airports having these
laser isotope analyzers, which are now instant.
You say you've been in Saudi Arabia,
you breathe into the isotope machine,
and it says you've been in Afghanistan,
or some more mountainous place.
It's another lie test they might start using.
I don't know, I don't think it's quite there yet.
But, I'm sure that's where they were going with it.
And yeah, well, that's a whole other story.
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