cc >> Thank you for watching
Wednesday Nite at the Lab tonight.
I'm Cassie Immel and I work here at the Biotech Center.
This evening we'll have Luke Winslow from the Center of
Limnology. Luke is a graduate student from
the Center of Limnology from here on campus.
He's currently working on his PhD with Paul Hanson and Emily
Stanley. His current research areas
include understanding the influence of physics on
phytoplankton, a type of algae, and dynamics and understanding
the extent and role of lakes at the continental and global
scales. Luke received his bachelor's
degree in material science and engineering also here at the UW.
Tonight he will enlighten all of us on the Global Lakes Ecology
Observatory program. So, without further ado, here is
Luke Winslow. >> Thank you.
[APPLAUSE] All right, as she said,
I'm Luke Winslow, and I was all prepared tonight to thank you
guys for braving the drought and coming here...
[LAUGHTER] But apparently I have to
thank you for braving the storm and coming here.
So, I'm going to be talking tonight mostly about the latter
half of some of my work which includes looking at what we've
dubbed global limnology, lakes on the surface of the Earth and
what they do. But a lot of it's also going to
be about my story, and it's really going to be kind of a
journey through what got me to where I am because a lot of
science is about individual researcher's backgrounds, what
our history is, where we came from, what particular experience
we've had that brought us to the research that we're at.
So of course I have to start with my hometown and my parents,
who are actually here tonight. I'm from Darlington, Wisconsin,
small town southwest of here. It's very famous.
It's very famous for two things: the Darlington Canoe Festival
and once Johnny Depp was in Darlington.
[LAUGHTER] This can be still found
on their website. It was a very big deal.
These are my parents, Amanda and Jerry Winslow.
I am the son of an educator, of a teacher, and of a mechanic,
and you'll see how that crops up in what I do for the rest of my
life throughout this presentation.
And I also would like to note that although it looks there
that they're avid downhill skiers, that was the first and
last time they were ever in downhill skis.
[LAUGHTER] Throughout my life I have been
around technology and the outdoors in kind of a weird
combination. And I realized, going through
some of my old photographs, that I was either fixing something,
building something, or outdoors was our primary activity.
And so throughout my life I wasn't really sure exactly what
I wanted to do because those things didn't necessarily mesh
together. I knew a lot of biologists who
studied biology but wasn't really in the technology realm.
I knew a lot of mechanics, technologists.
And so when I came to Madison I actually went into engineering.
And I did material science and engineering.
It was a fairly broad field. I was fairly interested.
My senior thesis ended up being this semiconducting properties
of pentacene, which is organic semiconductor.
I won't go into details of that. It was an interesting project.
While here as a student though, I have to say University of
Wisconsin Madison has a phenomenal variety, maybe you
already know this, but a phenomenal variety of
opportunities. And one summer, I was looking
for a job, I had previously been working at a Boy Scout camp many
summers before, and I decided I want to do something different
this summer. So I looked online at the UW Job
Center website, and I saw a job advertised for the Center of
Limnology, and I applied. And I got rejected.
And so I saw another job from the Center of Limnology and I
got it. And that summer then I did a
lake survey going through almost 200 lakes in northern Wisconsin.
The goal of the survey was to sample a random sampling of
lakes. So you just take all lakes and
pick randomly from them. And this is something that
actually really had never been done before.
Most surveys that had been done previous to that point usually
have some sort of size cut-off. So what we ended up doing is
driving down back forest roads, climbing through thickets.
I actually had the opportunity that summer then, from walking
through such dense overgrowth, to get both grass stains on all
of my clothes and also in my crotch area, because it was so
thick in that area. >> Too much information.
[LAUGHTER] >> It was just, it was
ridiculous. Anyway, I got asked then to stay
on. I had, all through high school,
I had a great deal of interest in computers and computing
technology. So I was asked to stay on by my
adviser, my now adviser, at that time boss, Paul Hanson, and to
work computer support in the department which I thought was a
fantastic opportunity. I also loved computers.
And this is really where I started to learn that computing
technology and the environment can go together.
And I was then given the opportunity to, oh wait, sorry.
So here I actually learned about many of the buoy and
environmental sensing opportunities we were having at
the Center of Limnology. So in 2007 I became what I call
the professional buoy boy. I graduated from my undergrad
here at Madison, and I got the opportunity to build and design
environmental sensing buoys which was really a niche and
very difficult to do at this time for lakes that we were
studying. And so here is the University of
Wisconsin Madison limnology buoy that's actually out at Mendota.
I've been deploying this buoy for the last five years now.
This is the fifth year that it's out there.
If anybody's been out on the lake in the last five years,
you've probably seen the buoy. At this point I have to mention,
a lot of scientists put this at the end of their talk, but I
want to mention that almost all of the research that you're
seeing today was in some part funded by the National Science
Foundation or private donors or the University of Wisconsin
directly. And they do an excellent job,
and they work very hard to make sure that the research they're
funding is pertinent, is useful. It goes through multiple levels
of review. It's very difficult to get
funding. I say this because there's been
recently some attacks against the National Science Foundation
by various groups arguing that it is a waste of taxpayer
dollars, but I want to say that it does phenomenal work and you
must examine the research in a broader context.
There was a specific example, and they actually parodied it in
this commercial where they were looking at the speed at which
shrimp could run, so they had shrimp on treadmills.
But this was a much broader study to understand shrimp and
what controlled shrimping operations and the yields of
shrimp which is a very, of course, important industry.
So these all have to be viewed in broader context.
So, this buoy work in Wisconsin actually ended up spawning then
the Global Lake Ecological Observatory Network.
There are a few researchers who were at a conference, and they
said, well, geez, you guys deployed a buoy, well we
deployed some buoys too, and we don't know anybody else who has
deployed these things so we should talk more.
And the other researcher was a researcher in Taiwan, and this
started a very small but very quickly growing network of
researchers who were interested in doing this thing.
You can see it was connected between Wisconsin and Madison
and also the northern point is the North Trout Lake Research
Station which is the limnology research site which is the
Northwoods in the main lake district in Northwoods
Wisconsin. And this quickly grew.
These were some of the very first buoys that were ever
deployed. The buoy was the buoy in Taiwan
on a lake that we'll see more pictures of later, a very
interesting lake that I'll talk about.
The yellow buoy is a lake on Trout Lake which is a very big
and very iconic lake in northern Wisconsin that I know a lot of
people are familiar with. And the third buoy there is
actually then a buoy on a less known lake, of course, but can
be, and we'll talk about this later, may just be just as
important to the grand scale of things.
This is a very small lake that we've dubbed Trout Bog.
It has no name. There was nobody living on it.
It is a lake that is about the size of this room, but it can
have very important, very big repercussions to the grand
scheme of things. So, then through this
involvement I had in GLEON, I first had the opportunity to go
to Taiwan and go to YYL. I always call it YYL because
I'm not very good at Chinese. But it's Yuan Yang Lake, I've
slaughtered it I'm sure, and this is a really phenomenal
lake. This is a lake in the mountains
of Taiwan. A lot of people don't realize
Taiwan is a very, very mountainous country, actually.
The majority of the people live on the western side of Taiwan,
but actually the eastern side is all mountainous region.
And this is in the middle of the mountains.
You can see these very steep mountains around the lake.
And what happens is that Taiwan gets hammered every year by
typhoon after typhoon. It's not uncommon to get hit by
two, three, four typhoons, what we would call hurricanes, in one
year in Taiwan. And this lake, when that occurs,
is small but in this very deep valley so it gets an absolute
ton of water. This water rushes down the sides
of the walls of the mountain, rushes into the lake, and what
this is is this is a thermal profile from the lake that we
could have only gotten by having the buoy and an automated sensor
package out there. We can't go out there in a
typhoon. When a typhoon hits, this lake
doubles in depth. So it goes from being a
four-meter deep lake to an eight-meter deep lake.
So this is the normal depth of the lake.
Imagine four meters higher. So it becomes a very dangerous
place, but the buoy survives this and you can see in this
temperature profile what will actually happen is this lake is
resetting. Normally a lake is, most lakes
are a stratified system. The top of the lake is very
warm; the bottom of the lake is cold.
Mendota is like this. Lakes in the Northwoods are like
this. Lakes in the Arctic for periods
of time are like this. Lakes in the tropics are like
this. They often have this stratified
layer. In this typhoon, so much water
rushes through, it resets the lake.
So we can kind of view this lake as a test bed, and we went there
one summer to look at it. And also for reference, the
total amount of rainfall that fell in those two days in this
example was almost a meter of rain.
So you can think of it as maybe 30 inches of rain in two days.
So a very large amount of rain. But, of course, that kind of
work is not always easy. This is the road leading back to
civilization from the lake. This was the year before I was
there. This typhoon doesn't just bring
a flushing of the lake, but it also brings major catastrophe to
infrastructure and roadways. So it can often be interesting
going to these places. I also ended up, we also then,
as this network grew, we found partners in Argentina, a group
looking at various lakes in Argentina.
Beautiful country. So we got to go and visit this
incredible chain of lakes, which I've never heard of such a
situation before, where in the span, this lake chain, from the
top point to the bottom point is perhaps 100 miles, and this
lake, Alcina, is almost purely fresh water.
And as you move down the chain of lakes, one lake drains into
the other lake and they become more and more saline to the
point where Epiquin, the bottom lake, it does not have an outlet
so all this salt just comes and collects.
It collects in this bottom lake, and it's a very, very
hypersaline lake. It is, I think, over four times
the ocean, but don't quote me on that.
You can actually see here, this is a picture of the lake.
This is us doing work on the lake.
Because it has no outlet, then it also has no ability to
regulate its depth. So there times in history when
the lake was much shallower and these trees grew, and then these
lakes became much deeper and all these trees were killed.
You can also see here at the bottom, there's actually salt
precipitated out from evaporation.
Every time a wave comes up, that salt sits there and it grows and
it grows. That's how salty this lake is.
And of course then the very salty, the famous Dead Sea.
This is actually fairly recent. This is only two years ago that
I got to visit the Dead Sea, and I can be honest that I came into
it with not that much interest. I thought, oh, the Dead Sea,
it's very famous, it's very salty, whatever, it's cool,
people swim in it. But if you ever get the chance,
wow. This is us in the water.
Just with our hands out we are floating in the water the way
you see it. People would hold rocks above
their heads because it's so buoyant.
You're just like a cork. But the disadvantage here is
when I got in there's salt precipitated on all the rocks.
It's very sharp. It's very jagged.
I, of course, slipped, scraped by back, and then after scraping
my back I get into hypersaline water, and I had a giant red
patch that hung around for the next week on my back.
So beware. There's also the very clear
lakes. Lake Tahoe in California and in
Nevada. It's on the border between
California and Nevada. Lake Tahoe is an incredible
example of an alpine lake, an especially big one in this case,
but an alpine lake that is extremely clear.
It gets very little nutrient input, unlike, say, think about
Mendota. Mendota we have an agricultural
region, we have a lot of nutrients that flow into the
lake. They fertilize a lot of algae.
Lake Tahoe is the opposite, and Lake Tahoe is incredibly clear.
Lake Tahoe has actually, I think it's lost something like half of
it's clarity in the last 50 years, but it's still, you can
still see a disc this big 26 meters down in the lake.
So 75 feet more you can still see a disc as you lowering it
down in the lake. It's an incredible lake.
And that's even after losing some of its clarity.
So very, very interesting world. The buggy, this is a lake in
Iceland. I have a colleague who's
actually an entomology student who's been doing work on this
lake, and I got the opportunity to visit last year.
And this lake is literally, in Icelandic it means midge lake.
Now, I came last year and I saw it and I thought, oh, cool.
It's a nice lake. It's a very interesting lake.
It has a very high phosphorus load.
It actually has a very natural, it's a naturally eutrophic lake.
So, like Mendota, lots of algae but not due to agriculture, not
due to anything like that. It's actually geologic.
It has a cold water input which brings phosphorus in which is
coming right out of the rock it's so volcanic.
And then there's a warm water input which is very warm.
It's something like 75-80 degrees all year round, and it
brings in nitrogen. And these two inputs come into
the lake and they merge and they create these huge algae blooms.
They fertilize these massive algae blooms.
And what happens then is that midges, which are the small,
they have a larval stage which is a worm that's in the bottom
of the lake, they feed on this huge algae bloom and they do
this. And this is a midge emergence.
So this wasn't the year that I was there, but this is several
years before. There's a midge emergence where
they form clouds. They're known to blacken the sun
as a cloud passes by the sun. They form these outrageous, it
is probably one of the largest midge emergence in the world.
And even more interestingly, and one of the things that the
researchers are very interested in in this system, is they're
cyclical. This is the year I was there,
and this was three years before it.
And this happens year in, year out.
It cycles. Seven years, six years,
five years, and they still don't fully know why.
Of course while I was there I had to get a sweater, and so
here's me in the outrageous Icelandic sweater.
And, of course, lakes that are actually very close to my heart,
which is the tiny, the very small lakes.
This is a small lake. All these small lakes, all these
names, we've given them to them. These are not official names.
None of these small bog lakes have names.
But we call this Timber Bog, and this is a small lake probably
even half the size of this room. That's a canoe.
If you put three canoes end on end, you could walk across the
lake. And this is in northern
Wisconsin, and there are millions of these out there.
They are everywhere. There is absolutely huge
numbers. And this is really where a lot
of the interesting research in global limnology lies because
big lakes we know a lot about. We can go once to a big lake and
we have good idea of what it is. And there are, potentially,
something like a thousand to two thousand lakes over ten square
kilometers in the world. But these small lakes you'll see
later, there are absolutely millions of these, and they're
much harder to understand. So, as I was saying, these lakes
are all part of the Global Lake Ecological Observatory Network.
These have all been, in one way or another, studied by
colleagues in our group. One of the central tenets of the
group is data sharing, expertise sharing.
The idea is that, as with lakes and with lake researchers, we
have to combine our efforts, our resources, and our data to
answer bigger questions in the world.
And this is actually a fairly outdated map.
There are a lot more groups that have now joined the network
around the world. I bring up, so, as I said, a lot
of where I started was in buoy work, building instrumented
buoys, and so, in some way, my kind of capstone project of that
before I started my graduate work, which I'll talk a little
bit more about, was the profiling buoy.
This was a buoy we built to take an instrumented package where it
would sense things like chlorophyll, blue-green algae,
and index of blue-green algae, temperature, dissolved oxygen,
and it would raise it and lower it in the water column.
And this is much easier said than done, I assure you.
You have a contraption to raise and lower something and then you
have waves and then you make it solar powered and then things
grow on it and it's definitely an engineering challenge.
But a good friend of mine, Jordan Reed, who is
unfortunately not here tonight, but him and I decided to take on
this challenge and build it. And we actually made the front
of the Wisconsin web page for this deployment in Lake Mendota.
We were all very proud of ourselves.
This here, as I said, this is Jordan.
This is myself. When we went to the front page
of the Wisconsin website, I was mentioned and Jordan's legs were
on the front of the website. It wasn't quite what we were
going for, but it was still very nice to have.
So, you might be asking, what are these buoys doing?
I gave that example in Taiwan a buoy can help you see what
happens to this typhoon. But lakes are extremely dynamic
and interesting systems. With these sensing platforms we
get a much closer view of what's going on physically and
biologically in the lake, and here's an example.
This is Lake Mendota and Mendota is a big wild lake and it gets
pretty windy out there and it can do really crazy things.
So what you're actually seeing here, up above this is that
temperature profile, and, as I said, this surface water is
generally very warm. Ignore these blips.
We were having some sensor difficulties at this time.
This is the surface water. These are deep waters that are
very cold. And this here then is a large
wind event. This is very strong winds coming
into Madison a single direction. They have so much strength they
take this cold water which is more dense in this warm water on
the top and they actually push the cold water to the side.
It sloshes the lake to one side because there's so much force to
one direction on the lake. You can actually see that with
these buoys. And then, actually, as it
recovers, you get these waves that continue to propagate
through the water column. We can also see, I'll say, how
the lakes breathe. And just like we do, just like
we need to do, we tend to take in oxygen and breathe out carbon
dioxide. Now, lakes do that in very much
the same way only, of course, they also photosynthesize.
So they have an extra nuance this.
So you can actually see here's an example from a lake up in
northern Wisconsin. This is the lake breathing.
When the sun comes out, photosynthetic organisms start
to photosynthesize. They take up CO2 and they
release oxygen. This oxygen is coming out into
the water. We can see it in dissolved
oxygen in the water. As sunset hits, you can see that
decrease again. So then this is all the other
organisms, the fish, the bacteria, and even the algae
they need to survive overnight, this is them taking in oxygen
just like we do. Here's Mendota actually just
moments ago. I regenerated this graph just
before I came. You can again see increases, and
there's a lot of interactions that are very complex with
physics and the movement of water, but on a good day you can
see a strong increase during the day and then a decrease at
night. There's a very good day again.
Strong increase, strong decrease.
We can see that as it happens. And this long-term trend is
actually the water heating up because warmer water holds less
dissolved gas. So this is actually the water
heating up these last few days that I'm sure you're all aware
of. It's been hot and the water has
warmed up accordingly. So, this is my story of course,
as I said. I started undergrad here doing
some work during the summer. I got to do this buoy work.
I got involved with GLEON all, I have to say, thanks to my
adviser and the people at the Center for Limnology.
What did this do? Well, this work really broadened
my perspective on the world. I saw lakes that were unlike our
own, lakes I never thought I'd see, environments and biomes
that I would have never experienced otherwise, and this
is just a map of some of the countries that I've traveled
through on my own or via work that I'm quite proud of except
for the fact that at this scale it's not very impressive.
[LAUGHTER] Europe just doesn't pop out
like you'd think it would. And so coming back and starting
my grad degree then, I wanted to go bigger.
I wanted to take a bigger perspective on lakes in the
world, and this was, as I said, I did a lot of software
development, actually, as an undergraduate, and this has come
back time and time again. I've used my ability to program
and to develop software to create tools that researchers
and myself can use. This is an online tool we call
Lakebase. The goal of this tool is to
index every lake in the world and collect any information we
might have about it. So this is a growing collection
of upwards of right now I think 10 million lakes in the world
and any information we have about those lakes.
You can just see this is, again, a shot of northern Wisconsin
that is centered on our Trout Lake Field Station.
These are lakes in the area, and each point is a lake.
So there's a lot of lakes. And why do we care?
As I said, lakes breathe and we take in oxygen,
we release carbon dioxide. Just like that, lakes are doing
the same thing. They're releasing oxygen, taking
in carbon dioxide during the day.
At night they're taking in oxygen and releasing carbon
dioxide. And they are everywhere in the
world, and they're part of this big global cycle of carbon.
And here, of course, is a fairly classic, I'm sure many of you
have probably seen a figure like this before.
This is showing carbon dioxide concentrations in the
atmosphere, or sorry, this is temperature, this is global
temperature. But this is what we're looking
at in terms of climate change and global warming due to
increased CO2 concentrations in the atmosphere.
And the big question here, and I have to say I don't have the
historical perspective that some of the older scientists do have,
but this challenge in recent history and this issue that's
going on has really opened up a world of science that has said,
whoa, we don't know how this works.
We don't know where all this carbon is going to and where
it's coming from and how these processes that put carbon into
the soil, that put carbon into oil, into carbon, we don't know
how these work. We don't know the rates.
We don't understand the sensitivities.
We don't necessarily know with a high degree of certainty what's
going to happen. And so this has been a huge
growing area of research, and you'll see it for, I'm sure, the
next many decades still. But, of course, I'm interested
in lakes. You'll notice this is a very
classic carbon cycle figure. Like you've probably seen your
water cycles only this is the movement of carbon through the
ecosystem. So we have fossil fuels, we have
people outputting carbon, we have carbon that's sitting in
the atmosphere, we have it going into trees, into the soil.
This is the ocean portion. We're saying how much is going
into the ocean, where's it going in the ocean.
Whenever carbon goes into the ocean, some of it might make it
to the ocean floor and kind of disappear for a period of time,
or some of it might get thrown back out into the atmosphere.
There's a lot of variables here. There's a lot of different
things going on at once. If you'll notice, though, this
figure doesn't have lakes, and it doesn't even really have
rivers. There's a small term here that's
going to forests or something, and there's nothing coming out
of this river. But this is probably where we're
probably missing something. When we focus only on the ocean,
on grasslands, and on forests and on human impact, we're
probably missing some big pieces of this puzzle.
Lakes are small, very productive environments, and so there's a
lot of questions this brings up. What kind of role do lakes play?
How much carbon are they bringing in?
Or are they releasing excess carbon?
Are they taking carbon from this term here that's coming into
forests and are they putting it back out in the atmosphere?
We call that net heterotrophy. Are lakes a source or a sink for
carbon dioxide? Many questions and we have only
a few answers. As I said, there's a lot of big
lakes, and there's even more small lakes.
What do these small lakes do? How much do we even know about
these small lakes? Many of them, millions of them
have never been visited by a researcher.
Many of them we don't even know basic numbers about them.
Many of them are actually too small to see by satellite
imagery. We'll see that here in a bit.
And of course you can make the comparison too.
Ocean is 71% of the Earth's surface area.
Land is something like 28%. And then lakes and rivers are
probably around 1%. You say, okay, well, 1% isn't a
very big number. Do they really matter?
But they probably do. The ocean, while it covers a
really big portion of the world, a lot of the ocean isn't doing
much. And they call this ocean
productivity map. And this is based on satellite
imagery. And what they're doing is
they're trying to measure the amount of chlorophyll that's in
the water. So what you're seeing here is
the red zones are hot. These are where there's a lot of
chlorophyll, there's a lot of productivity, there's a lot of
biological activity in the ocean.
The areas where it's blue and purple, it's very low.
The ocean, in many regions, is a big desert.
There can episodic events where they get slightly higher
concentrations, but there's very little going on in much, much,
much, much of the ocean. So we can't really think about
the ocean purely as being 71% of the Earth's surface area.
It's not just how much surface area you have, it's also what
you're doing with that surface area.
And the ocean, for a large part, in many parts is not much.
Now, of course, the ocean is huge.
I'm not trying to downplay the ocean.
It's a very big part of this. But it's not necessarily as big
as one might think. So what role do lakes play in
this grand scheme? And I'm not going to come out
here and tell you and answer. I apologize.
This is an ongoing area of research.
This is something that some people have made some estimates
on, but we are still struggling with some actually very
fundamental questions that get at this, and I'll talk some more
about this. But one of the things that we
first need to know to answer what role lakes play is how many
lakes do we have? How much surface area is there
in lakes? How much volume is there in
lakes? How productive are they?
How much photosynthesis is going on in them?
Are they sources or are they sinks?
There's a lot of questions that are bound up on this.
And something that I've been researching then, I'll come back
to this, something I've been researching, and I'll get into
this in a bit, I've been researching and trying to figure
out how we can understand the number of lakes and the surface
area of lakes on the globe. And why do we need to know this?
Well, we need to figure out a way to start to estimate these
very important things at broad scales.
We need to figure out, okay, well if we don't know what lakes
are doing, well let's figure out what one lake might be doing and
then multiply it times the number of lakes.
Well, we can't exactly do that because there are small lakes
and there are big lakes and then there are really, really big
lakes. Here's a figure that doesn't
come out super well, but this is the surface area of Lake Baikal,
this is the surface area of Lake Mendota, and this is the surface
are of Trout Bog. And, actually, on a log scale in
square meters, Baikal is closer to the surface area of the Earth
than it is to the surface area of some of the small lakes.
So lakes span a huge gradient. This is actually, this faded
outline here is Baikal, and this small dot here is Mendota, just
to give you an idea of the scale that we're dealing with.
So, how do we look at this? How do we start to take this
weird collection of big lakes and small lakes and medium size
lakes and start to make sense of it?
Well, a researcher named, very famous researcher in limnology
named Robert Wetzel, Bob Wetzel, in 1990 basically first proposed
the idea of just looking at patterns in lake size.
And he took a very simple look at it, and he said, okay, let's
look at each lake area size class of lakes, so lakes that
are a thousand square kilometers, a hundred, ten, so
on and so forth, and let's look at how many of those lakes there
are. Now, this is a figure he kind of
drew up. This is a theoretical figure,
but he theorized based on what he knew and based on what he
found at that time that this followed a regular pattern.
This is what's commonly known as a power law, or if we're
thinking about spatial statistics it's often called a
fractal process which means that there is a known, if you know
the number of a big thing, if you know there are 10 lakes that
are 1,000 square kilometers, then there's probably 10 times
as many lakes that are 100 square kilometers.
And there's probably 10 times as many lakes then that are
10 square kilometers. And you can start to make this
kind of assumption of a process of a model and use it to
estimate globally. We can count the number of large
lakes, and we'll see here in a second.
And this actually hinges on a very cool thing, a very cool
kind of fractal nature of geology, fractal nature of the
universe. Let's not say the universe but
geology on Earth. And you can take, actually, a
very simple process that scales many sizes, it can act on
inches, on kilometers, on miles, and if you create this fractal
theoretical surface, like this one here, you can see here.
This is a theoretical fractal surface that I've created.
If you take this and you just pretend, let's say you dump
water on this. Of course we don't do this in
the computer. It would not be good for the
computer. But you can theoretically dump
water on it, and you can see where lakes form.
Where do they pool? And what you get is a surface
that looks like this here. And actually then, if you take
and, just as we did here before, if you plot the number of lakes
at each size, then you get this relationship.
This is size and this is the number.
This very linear relationship again that each time you go up
in size class, you get 10, you get a known number more of these
lakes. So we can go on and we can say,
okay, if we know this and we know the large lakes, we can see
the large lakes from space, they're fairly easy to identify,
there's not many of them, and this was work done where
they indexed, they took satellite imagery, and they
looked at all of the large lakes and all of the large wetlands in
the world, and they released this phenomenal data set.
And if you take this portion of the large lakes you have, you
can see here it actually only goes down to 10 square
kilometers which is just a bit under the size of Lake Mendota,
and you then extrapolate out, you go out this knowing that
relationship is steady into the small lake size classes, you can
start to estimate how many lakes there are in the world.
And I wouldn't be a researcher up here talking unless I talked
about some literature. So there was a very influential
paper that was published, and this gets cited all over the
world. Downing et al, 2006.
He's actually a researcher in Iowa, I think Iowa State, I
forget exactly, and he then estimated from this relationship
how many lakes there are in the world.
And he said a lake stopped at a 10th of a hectare which is 100
square meters which is not very big.
It's probably a tad bigger or it's a tad smaller than this
room. If you think about 10 meters on
a side, that would be 100 square meters.
So that's the cutoff. No, I did that wrong.
Sorry. Sorry, a 10th of a hectare is
1,000 square meters. So 23 meters on a side,
something like that. So it's not a very big site
class. Nonetheless, he estimated there
were something like 304 million lakes in the world.
And the vast, vast, vast majority of that, because of the
way this relationship works, the vast majority of those are
small, small, small lakes like those little bog lakes I was
talking. Like your backyard pond, things
like that. So my work then I wanted to see,
his was all theoretical. He took that relationship and
said, okay, theoretically, how many lakes are in the world.
I took a recently released data set from the United State
Geologic Survey, and I have to commend them on their phenomenal
data sets. They are par none in the world
in terms of understanding how the water and the land resources
in a country, the US has done a phenomenal job and much of it
has been done by the USGS. But I take this very large data
set that they had released, extracted all the lakes from it,
and then started looking at what kind of distributions of lakes
we have in the US. It's actually very revealing.
You can see the darker the red colors are a high abundance of
lakes. The blue is much lower abundance
of lakes, if not zero. And of course the southwest has
very few, not surprising. But, actually, this southern
central Midwestern region really pops out.
There's a lot of lakes in this region.
Now, it turns out, though, we have to be careful because just
the number of lakes, as I said, number isn't everything.
The abundance is deceiving. These lakes in the Midwest here
are small, small agricultural ponds.
Millions of agricultural ponds that have been built to water
livestock and things like that. If you look at the surface area,
the percentage of surface area that's covered, the figure looks
completely different. I can show you again.
Here you can't even see the Northwoods of Wisconsin, and
Minnesota looks a little hot but not really like there's a lot of
lakes. But here, again, you can see
this northern lake region really pops out.
Minnesota, again, really striking and even further west
you see hundreds and thousands and thousands of lakes.
Florida, actually surprisingly, I have to admit I have probably
a Wisconsin bias, but Florida is an extremely lake-rich region as
well. And of course Alaska.
That is something that has been known for a long time.
But one of the incredible statistics that came out of this
then is that looking at this, if you break it up by state, if you
say, okay, how many lakes are in a state, Texas has around a
million and Alaska has around a million.
But, again, in Texas, this is this region here, there's this
agricultural pond building, and in reality, the actual surface
area in Texas is much lower. So if we're thinking about the
total surface area lakes in the world, then Texas doesn't pop
out quite as much. Now, back to that relationship.
So, Downing had said, okay, it goes straight on all the way
through into small size classes. This is the work, this is
looking at the actual data set from the USGS, and you can see
this blue line is the line that Downing et al basically used in
their results. This, the black dots here that
basically look like a thick black line, that's the actual
data set. That's the observed lakes in the
US. And you can see it doesn't quite
make it quite as high as Downing had originally estimated.
And on top of that, it starts to deviate away in these small size
classes. It's not longer a straight line.
Now, that straight line makes sense in the fractal world like
I talked about, but it's not clear yet what's going on to
deviate this line downwards. It's an area that I'm actively
working on right now as part of my PhD thesis, and there's a lot
of potential issues. We might just not be seeing
these lakes. They're very small, and
satellite imagery is not perfect, especially in forested
areas and things like that. You don't always get great shots
of these lakes. We may not be hitting them all.
These small lakes, they're very small.
They may just evaporating. In dry areas, there may be the
potential for the lake to exist but they may just be evaporating
away and not actually existing. They may not have enough water
supply to keep them in existence.
And then in this large size class I just highlighted, this
is a known issue. This is kind of the idea that
we're simply not on an infinite plane so we can't have infinite
sized lakes. In a perfect world, it would go
out further, but we are constrained to the size of the
world. So, anyway, yeah, as a quick
synopsis, the original estimate said in the US there would be,
say, 20 million lakes. Here are the estimates.
My estimate based on the work that we've done says probably
about 10 million, but of course because that change in the
number is up here in the very small lakes, as I said there's a
lot of small lakes and a well-known number of large
lakes, it doesn't really change the amount of surface area a
whole lot in our understanding. So that's something to kind of
take away. Another little tidbit you might
be interested in, unfortunately Minnesota still wins.
Even if you look at all of the lakes in Wisconsin and all of
the lakes in Minnesota, Minnesota wins both in number
and they have about the twice the surface area as us too.
So we can leave that to rest. There's no way.
There's been lots of debates. It depends on if you look at
named lakes or unnamed lakes, but either way they,
unfortunately, win. Yeah, so this is kind of where
my research is sitting right now, taking a look at broader
scale. The next step is to understand
kind of more, use more of a theoretical underpinning.
What does this huge scaling of lakes, these lakes go from being
the size of the state of Wisconsin almost in Lake Baikal
to the size of this room, what does this mean?
The lakes of this huge magnitude can't operate and can't behave
the same way that a small lake does, and what can that tell us
about our understanding of lakes as is?
Another area I'm looking at is that lakes are not just their
surface area. Historically in our field, we've
looked at the surface area of the lake and we've added it up
and we've said that two small lakes kind of means the same
thing as one big lake and so on and so forth.
But a lake is also its volume. A lake is also its perimeter.
Things fall into the lake across its perimeter, carbon and leaves
and things make their way into the lake.
The volume of the lake has processes like respiration and
it has thermal processes, the thermal mass of the lake is
dependent on its volume, and of course then the area which we've
thought about a lot. But expanding these notions to
broad scales is part of my work also.
And, of course, understanding and integrating these lakes into
global models. Understanding how they behave,
understanding what they do when we look at the globe, and so
forth. And lastly, a personal interest
of mine is also direct public engagement.
It's why I'm here today. Tom had asked me to present, and
I was more than happy to because I've really learned that science
is nothing without communication, and I think that
scientists in the past 20 years, 30 years, have done a not
phenomenal job with actually direct public engagement and
communicating what they know to the broader public.
And so I'm interested, I'm very looking forward to if there's
any questions after the talk here.
And I've been working also with programmers and, of course,
myself, as I've programmed, to build more better websites and
better outreach tools that can engage a broader set of people
however they want to be engaged with the science.
I'm really open to the ideas. But this is just an example.
This is an iPhone and Android application that you can get the
Lake Mendota buoy data from, and it's turned out to be a huge hit
with the sailors. For some reason they like to
know what the wind is or something.
[LAUGHTER] It's proven to work very well.
And, as I said, I've been dealing with the Lake Mendota
buoy, and so I have been blogging.
If anybody's interested in the trials and tribulations of
running a buoy on a lake like Mendota, I'm happy to take any
questions or considerations in that part.
And it's on the web if you want to look.
There will be a link based on the Wednesday Nite at the Lab
website. So, are there any questions?
[APPLAUSE]