Original subtitles

Lakes are living creatures.

These precious reserves of water

live and die according to distinct natural cycles.

Their peaceful waters seem dormant

yet they teem with mysterious life.

Lakes only reveal themselves to the men and women

who take time to patiently linger beside their shores.

Together, we are going to discover their secrets.

Surrounded by large stretches of arid land,

and looming mountains, the Great Salt Lake

is sometimes called America's Dead Sea.

It's salt content is so high, it seems unfit for life.

Nevertheless, millions of birds flock along its shores

to feed and mate.

Though its water is saltier than the ocean,

the lake is a complex ecosystem,

home to amazing creatures

and filled with unsuspected treasures.

How can such incredibly diverse lifeforms have flourished

in an environment as extreme as this?

Located in the northern part of Utah, one of the driest

states in the US, the Great Salt Lake covers an area

of more than 4400 square kilometers.

Nearly two million people live

in the region surrounding it.

A biologist at Westminster College,

Jaimi Butler has devoted herself to the study

and protection of the Great Salt Lake.

- I grew up here in Salt Lake,

and I'm an avid Great Salt Lake lover.

I'm passionate about it.

We were taught that Great Salt Lake isn't so great,

that it smells, that it's buggy, that it's a dead lake,

that nothing lives here,

that there's no value in the lake at all.

Great Salt Lake has a lot of different microenvironments.

So even though Great Salt Lake is salty, there are

lots of things that have adapted over time

to live and thrive in its salty waters.

The Great Salt Lake region regularly receives

heavy rains blowing in from the Pacific Ocean.

How is it then, that the lake's water is so salty?

The reasons for this lie in the mountains surrounding it.

In spring, the snow and ice that have accumulated

over the winter begin to melt.

An extraordinary amount of water gushes down

the mountain slopes and into the rivers that feed the lake.

And yet, this exceptionally pure water changes

long before it reaches the lake.

It is a phenomenon that limnologist Wayne Wurtsbaugh,

who has been studying the lake for over 30 years,

is very familiar with.

- One of the reasons the Great Salt Lake is salty

is because these rocks behind me weather through time.

These, over tens of thousans of years, break down,

release calcium carbonate, magnesium carbonate,

sodium chloride.

These flow down into the Great Salt Lake,

and if it was a normal lake with an outflow,

those salts would just flow on and eventually

make it to the ocean.

But Great Salt Lake is a terminal lake,

which means the only way the water leaves

is via evaporation up into the atmosphere.

When that happens, the salts are left behind,

and we wind up with a salt lake.

Since the lake is a closed circuit system,

a phenomenal quantity of mineral salts have

accumulated over the centuries.

Two million tons more salt arrive each year,

to the delight of industrials who've managed

to turn it into a profit.

With its water much too salty for any use,

this unpopular lake must have been quite a disappointment

to the pioneers who settled here in 1847.

Nevertheless, with advanced irrigation techniques,

these persevering farmers managed to transform

part of the arid terrain into fertile land

and founded Salt Lake City.

After their settlement, came the building of the railroad,

and a causeway spanning the lake from East to West.

This massive construction has had a considerable

impact on water flow in the lake.

When seen from the air, today's Great Salt Lake

looks odd, as if a line had been drawn straight across,

dividing it into two distinct parts of different colors.

The railroad causeway has created two disconnected parts

of contrasting hues.

- We're standing on the shore of the north arm

of the Great Salt Lake.

You can see the pink water.

Gonna take a sample here

and measure the salinity of the water with something

called a refractometer.

I can look through this and see a line

that tells me what the salinity is.

And, as expected, it's about 30 percent

salt by weight.

You can compare that with the ocean,

that's about, oh,

close to 10 times what the ocean is.

North of the causeway,

there is practically no fresh water that enters the lake.

The occasional rains cannot make up for solar evaporation.

Nevertheless, despite the extremely high salinity

of this environment, cut off from the rest of the lake,

it is not completely devoid of life.

- We have bacteria in here, and we have green algae,

but even the green algae have red pigments that help

protect from the sunlight, and so the water looks pink.

And if we were to go to the other side of the causeway,

just 30 meters away, it looks green,

so it's really a striking difference,

and a whole different community over there.

The reason the water is green

south of the causeway, is that its salinity is much lower

than the water to the north.

This is where the three major tributaries flow in,

the Jordan, Weber, and Bear Rivers.

Here, the salinity is only 15 percent, a tolerable

level that makes it possible for life to develop.

Located on one of the main migratory routes in western

North America, the Great Salt Lake is a strategic stopover

for millions of birds migrating north in spring.

Some merely pass through, while others, such as

the White-faced ibis, build their nests and raise

their young in the marshes.

As summer approaches, American avocets seek food

in the areas exposed by the drop in water level.

Survival in this shifting habitat is a constant struggle.

But it is north of the causeway that we find one of the

most hostile environments of the lake.

On this hot July morning, a motley procession

comes rolling down the causeway.

Summoned by biologist John Luft, a group of 30 volunteers

are about to brave the ultra-salty waters

of the north part of the lake.

- We wanna get done before it gets too hot.

Also there's a storm supposed to come in this afternoon

maybe, so if we can get off the water before the wind

picks back up, then that would be great.

The group's destination, Gunnison Island,

over 35 kilometers away from their launch point.

John Luft is in charge of several research programs

on the Great Salt Lake.

Each year, he heads to Gunnison Island to carry out

a delicate mission.

- There is very few people who has set foot

on this island.

Surrounded by the pink waters

of the north part of the lake, the island

is particularly inhospitable.

No trees here, only rocks and salt.

- Yeah, go ahead.

It looks like one of them

moved out of the shore.

- Yeah, we don't see 'em here, but are you ready

for us to come over?

Ready pretty quick.

- All right, we're on our way.

Okay, go ahead.

The team have spotted the object

thousands of young pelicans

that hatched on the island a few months earlier.

Each year, over 10,000 American white pelicans,

close to 20 percent of this bird's world population,

stop in this extreme habitat to breed.

For these birds, Gunnison Island is a sanctuary,

protected from the exterior world by ultra-salty water

that no predator would dare cross.

The clumsy young pelicans haven't learned how to fly yet.

Their parents have left them on their own

to go search for food.

This leaves the scientists with only a few hours to band

the young birds before the adults get back.

- It's important for these birds as protection

for nesting area, not so much as a food source.

The closest food source to Gunnison Island is

Bear River Bay, which is about 30 miles east of us.

Here in the bay's less salty waters,

the pelicans catch fish they can then

bring back to their young.

Safe on their island, the young pelicans wait impatiently.

- We like to track them, and the easiest way to do that

is using these patagial markers, because they're

really visible outside the wing, and

a lot of bird watchers can see them,

and we don't need the bird to die to actually

get a return from an observance from these birds.

These markers have already enabled

scientists to solve a few mysteries.

We now have a better understanding

of the journeys made by the pelicans and

where they go to find food.

- And we have record, through the banding record,

the bands that we're putting on, that show the travel.

Pelicans will travel up to 300 miles,

round trip, just to forage and bring food

back to the chicks.

It isn't easy to catch the young pelicans.

The volunteers need to pick up the pace, since the adults

are already on their way back.

The scientists hope their markers will help them

understand why only 25 percent of the young

survive each year.

The work is completed in the nick of time.

At last, the adult pelicans can feed their famished chicks.

For the moment, Gunnison Island offers pelicans

the perfect refuge.

But this might not always be the case.

Scientists have noted that since the 1990s,

the level of the lake has been diminishing regularly.

Some of them fear that the trend,

partially attributable to global warming,

will only intensify in the future.

One day, it may very well be possible for predators

to reach the pelican sanctuary.

To understand what the future holds,

sometimes we need to look to the past.

150 kilometers west of the lake lies a vast plain of salt.

It is one of the flattest zones on Earth and the ideal

place for heading back in time to the origins of

the Great Salt Lake.

- Here we are, Geneviève.

- Sunrise on Great Salt Lake.

Well, it isn't really Great Salt Lake,

we're at the Bonneville Salt Flats.

It's the climate change of hot and dry

versus wet and cool that makes this place

just be a total contrast.

This place was once

an immense expanse of water,

Lake Bonneville, the precursor to the Great Salt Lake.

- So we'll start with this one.

30,000 years ago, climate changed, globally,

and we went into a colder, wetter environment

here in North America.

It only took, probably, fewer than a hundred years

for it to go from Salt Lake to Wendover.

This is big changes.

It was a large lake, about the size of Lake Superior,

and that lasted for about 20,000 years.

At it's highest level, Lake Bonneville

covered nearly two thirds of Utah.

This gigantic reservoir contained a hundred times

more water than the current lake,

until a cataclysm took place.

- We had this failure that everybody's enamored of,

I am too.

It's called the Bonneville Flood,

and its outpouring, this was this whole lake

dropped 300 feet in less than a year.

The natural barrier retaining the water

in the north part of the lake abruptly gave way.

- Either there was an earthquake or a landslide,

or any number of things happened, and it failed.

And once it failed , just like butter,

it just went right through it.

It equals all of today's rivers combined,

the Ganges, the Amazon, the Mississippi.

With all the water that drained out,

the level of the lake radically diminished, leaving

traces on the landscape that can still be seen today.

Next, the climate began to warm up, and the enormous

Lake Bonneville gradually evaporated,

slowly changing into a desert of salt.

Today, the only remnant of this former inland sea

is the Great Salt Lake.

On a smaller scale, the fluctuations

in water level have continued.

From one year to the next, from one season to another,

the lake level varies.

This is easy to see when you compare two photos

taken two decades apart.

- So this image is from the 1960s,

this image from the 1980s.

What do you want to do first?

- I'd like to go to Antelope Island.

- Antelope Island is here.

Notice that it isn't an island.

- In my picture, Farmington Bay is huge.

- Stansbury, not an island.

How about on yours?

- Yeah, mine's an island.

Aren't you special?

I wanna do Bear River Bird Refuge.

No water, empty.

Barely 20 years separate these two pictures,

yet the difference is blatant.

Islands become peninsulas, then return

to being islands once more.

In this flat shallow lake, the slightest shift

in water level changes the shape of the shoreline,

causes floods, or dries up entire habitats.

The lower the water level, the higher the salinity.

Each fluctuation of the Great Salt Lake

has immediate consequences.

In the north part of the lake, an amazing sculpture

appears and disappears, in keeping with these variations.

Spiral Jetty, Robert Smithson's work of land art,

required several tons of basalt and rock to create.

- I remember the first time I came out here with students,

the water level was so high,

that we canoed over Spiral Jetty.

We couldn't even see it under the water.

- Spiral Jetty is a very artistic water gauge.

- It is that, and now I can't believe we're walking on it,

it's dry as a bone.

Bonnie Baxter, a biologist

with Westminster College is an expert

in the lake's microorganisms.

For her, the Spiral Jetty area amounts

to a true outdoor laboratory.

- What we're out here to do today

are find microorganism that can live

dried up in salt crystals,

because some seasons we find very little water,

and we know that the microbes are still alive.

The microbes that live here have learned to

pump the salt out and to make things inside their cells

to compensate, like lipids or sugars

to balance their membranes in the water.

And so they have these special secrets for life

in this place, and what we find is

the microbial community that's here in June

is different than the microbial community

that's here in October.

And sometimes we see new microbes,

new species we've never seen before.

So if you follow the lake over time,

you will find the microbial diversity changes,

which is beautiful.

It's surprising to me that so many people think

there's no life in this lake.

Cultured in a laboratory for several months,

the samples taken by the scientists have allowed them

to understand why the lake changes color

from one season to the next.

- As the lake gets more concentrated

in a species under the genera of halobacteria,

we would see a purpley color.

If it were more concentrated in an algae we call

dunaliella salina, it would be more like my shirt,

it would be more of an orange color.

So this is evidence, just visually,

of changing microbial communities.

The bacteria give the lake its stupendous

colors, but also provide the main source of food

for other creatures, which are just as strange.

In the south part, a large proportion of the

biodiversity depends on the tiny organisms that thrive there

in spite of the salt.

On this day in early summer, Kyle Stone is

taking samples that are of the utmost

importance for biologists.

What he's collecting are tiny crustaceans called

brine shrimp.

These creatures play a crucial role

in the lake's biological cycle.

- We collect these samples to determine the

number of shrimp throughout the lake

per liter of lake water, and we use that

for management purposes,

to manage the brine shrimp harvest season.

Brine shrimp provide food

for several varieties of birds,

and are remarkable creatures in and of themselves.

By evacuating the salt they absorb, they're able

to survive in water with a mineral concentration

of over 50 percent.

The eggs they lay can survive temperatures

higher than 100 degrees Celsius.

In summer, brine shrimp feed on the green algae

that proliferate in the lake during the winter.

They act as filters, removing the algae from the water

in a few months' time.

This explains why the water gradually loses

its green color and even ends up a veering blue

in the fall.

But the amazing brine shrimp are not the only

secret harbored by the Great Salt Lake.

One part of the shoreline seems to be made up

of strange living rocks that Wayne Wurtsbaugh

knows quite a lot about.

This is a stromatolite, which looks a lot like rock,

and, in fact, it really is rock.

But it's formed by life,

and the life that forms it is the cyanobacteria.

It's a type very similar to algae, and because of the

cyanobacteria in the solid substrate,

we have brine flies growing on this.

Three generations of flies

grow on these stromatolites each year.

The fertile rocks provide larvae with shelter

and an abundance of food.

- These stromatolites that we're walking on now

are probably half a meter thick,

or something like that, and have been growing

for a long time.

They grow over tens of thousands of years,

and if we look down, we can see tens or

hundreds of thousands of brine flies.

Some are sitting on the surface film of the lake,

making almost a solid mat.

In the summer, the density of the flies

reaches its maximum.

Any, other than a scientist, would consider them a plague.

But Jaimi and Bonnie know that these insects

are an essential component of the lake's ecosystem.

- The flies at Great Salt Lake still amaze me

after working out here for all of these years.

You can see the sparkle on the surface of the water.

Those are the adults that are laying their eggs on the

water in the Great Salt Lake.

The flies are cycling nutrients by eating

these microbes on the bioherms there,

specializing on the benthic microbes that

live on the bottom of Great Salt Lake and feeding on them.

People have estimated up to 370 million pupa cases

on one mile of shoreline.

This is incredible biomass for the birds that

migrate here all year round.

The abundance of these flies

helps explain why the Great Salt Lake

is one of the main stops along the migration route

of countless bird species.

But could this cornucopia turn into a threat?

Over the past few years, scientists have grown alert

to the presence of mercury in the bodies

of certain waterfowl.

There is little doubt as to the origin of the mercury.

It comes from industrial waste.

The highly toxic metal leeches onto the bottom

of the lake in the sediment that constitutes

the fly larvae's food.

These larvae in turn are the main food supply

for the most highly contaminated

bird on the lake, the Common Goldeneye.

Scientists have discovered the fly larvae

are at the bottom of a toxic food chain, where the

concentration of mercury gets higher with each link.

But are the flies the only vector in this lethal sequence?

Don't other animals contribute to

spreading the poison?

- Look in front of us.

We have at least a hundred spiders,

big spiders.

These are Orb Weavers at Great Salt Lake,

so birds aren't the only ones that eat the flies

out here at Great Salt Lake.

Orb Weavers also love to feast on all of those

billions of flies that are behind us on the

shorelines of Great Salt Lake.

Until now, the role the spiders play

in the contamination of other species had not

been clearly established.

- I had begun working with one of our faculty members

at Westminster College who had some preliminary data

on how much mercury was in the spiders at Great Salt Lake,

and had talked to the media about this, and a photographer

contacted us right away and said, "I have pictures of birds

"that are feeding these spiders to their nestlings,"

which is a very interesting way for a scientist

to gain information, through a photographer.

Intrigued by the photos,

researchers were eager to learn more.

They installed a miniature camera near a nest.

First ingested by flies, then by spiders and birds,

the mercury becomes more concentrated as it

progresses along the food chain to man.

Certain ducks with mercury levels that are too high

have been banned from human consumption.

The presence of this toxic metal in their main source

of food has transformed the Great Salt Lake into

a risky stop off for America's migrating birds.

Summer is almost over, and there are

fewer and fewer flies.

The birds have had a chance to stock up on food

and are ready to leave the lake

for regions where the winter is milder.

Autumn heralds a new stage

in the biological cycle of the lake.

The moth of October marks the opening

of a very particular fishing season.

The brine shrimp have laid an actual treasure.

Billions of eggs that amass in large reddish swaths

that are visible from the sky.

Destined as food for farmed fish, these eggs,

called cysts, bring $125 million

into the local economy each year.

Dozens of boats attempt to make the most

of these few months of harvesting under the

watchful eye of John Luft.

- As we manage the brine shrimp fishery,

we have the possibility of

over-harvesting but also under-harvesting.

So we rely heavily on the brine shrimpers

to actually harvest the exact right amount.

That's what all of our monitoring during the course

of the season is for.

To ensure the sustainability of the resource,

the harvesting of brine shrimp eggs

must respect strict quotas.

If too many cysts are harvested, the next generation

will have a hard time replenishing itself.

But if not enough are harvested, the adults

will proliferate to an extent that could

lead to a shortage of phytoplankton.

This would prevent young brine shrimp

from reaching maturity and being able to reproduce.

The cysts are incredible creatures.

It takes 250,000 of them to fill just one teaspoon.

But they are astonishingly resilient.

They can survive many years

in a state of complete dehydration, and are able

to adapt to extremely different salinity levels.

Fishermen aren't the only ones who appreciate the presence

of these tiny shrimp that play a major role

in the ecosystem of the lake.

Biologist Maureen Frank has organized an expedition

to study one of the largest and most

prolific populations of migratory birds on the lake,

the Eared Grebe.

Another sort of angling begins,

for birds.

- The reason that Eared Grebes come to Great Salt Lake

is to fuel up before migration.

So they come here and they eat a lot.

And when they get here, they lose the ability to fly

because their wing muscles get smaller

and all of their digestive organs get bigger,

so that they can put on as much weight as they can.

It's a dream come true

for the scientists studying them.

The researchers drive about a dozen into their net,

which they will then equip with transmitters.

This will allow Maureen to record the birds' movements.

- We need to know how many are out there.

We need to know what they're eating.

We need to know where they're eating

to ensure their long-term survival.

Half of North America's population of grebes

comes here every year.

- These transmitters are helping us figure out

how they move around the lake.

While the eared grebes are here, there's also

harvest of brine shrimp cycts

that's going on at the same time.

So it's important for us to know what parts of the lake

are important to the birds so that we can

make sure they still have places that are

good for them to forage.

And we monitor that, so that we can have the birds

stay healthy and have a brine shrimp cyst industry.

As valuable to the birds

as to the fisherman, brine shrimp are the lake's

largest biological treasure.

Without them, the Great Salt Lake would not be the

main stopping point for migrating birds

in the southwestern United States.

Fall is the best season to discover Antelope Island.

Located in the southeastern part of the lake,

the island, with its 40 fresh-water springs, is an oasis

in the midst of the salt water desert.

This makes it a natural sanctuary for its remarkably

diverse wildlife, which includes the pronghorn,

the only antelope endemic to North America.

The most surprising animal that lives on the island

was once found in abundance on the continent.

Just 200 years ago, 50,000 bison still roamed

the American plains.

But the arrival of the pioneers proved fatal to them,

and by 1890, hunting had reduced the population

to a mere few hundred.

President Theodore Roosevelt took the initiative

of reintroducing the species in certain

protected zones.

- The bison actually came in 1893 to the island.

At that time, we brought 12 animals:

four bulls, four cows, four calfs.

So they felt that it was an isolated place

that they could protect them.

Today, over 600 bison live

on Antelope Island.

The largest herd in North America.

Although few of its landscapes resemble the arid plains

of former Lake Bonneville, the island remains a privileged

spot for the protection of a legendary creature.

They are so prolific here that there numbers

need to be managed.

This has spurred the Great Buffalo Roundup

that is organized on the island each year.

- Okay, when we get them up into the corrals,

they'll have fences on both sides.

We've got to push 600 buffalo through a 30-foot gate.

So once they get going through the gate,

back off and just let them go.

Once we get 'em going, just take it easy,

they'll all walk in.

Each year, hundreds of volunteers

flock to Antelope Island from across the United States

to participate in the roundup.

A number of bison will have to leave the island,

but which ones?

The bison are herded towards corrals,

where they can be examined and sorted.

The enormous herd is driven toward the pens.

The bison are selected according to

genetic criteria.

- There's a lot of bison these days that have

bovine genes in them, bovine being cow.

They're cattle genes.

So what we want to do this year

is auction off anything that we find bovine in

and to get a pure bison herd, which would be

fairly unique throughout the country.

The bison undergo medical examinations

and DNA testing, the results of which will determine

which animals get to stay on the island

and which ones must leave.

The tests have revealed that 99 percent of the bison

on the island are free of bovine genes, which actually

makes them one of the purest herds on Earth.

More than ever, the Antelope Island bison herd

is a resource worthy of protection in the exceptional

habitat provided by the Great Salt Lake.

Autumn is drawing to a close,

and life in and along the lake is gradually changing.

In the north, the heavily-salted water glistens bright pink,

while in the south, the water has been cleared of its algae

and presents a clear blue shade.

To the east, where the fresh water from rivers

blends with the lake's saltier water,

we find a vast network of habitats.

These wetlands are a refuge for over 200 varieties

of birds, but are also one of the spots most susceptible

to drops in water level.

To survive in the shifting conditions, animals, plants,

and microorganisms need to constantly adapt.

All these life-forms depend on the rhythm of the seasons

and the water level in the lake.

John Luft can't help but acknowledge

that this ecosystem is gradually drying up.

As the season draws to a close, we find

the largest bird population up in the northeast,

near Bear River Bay in the marshes,

where the vegetation is lush and the water less salty.

Temperatures are dropping, and the water will soon freeze.

For some birds, this is their last chance for a good meal.

The Bear River Refuge is the largest wetland

in the Great Salt Lake ecosystem.

For biologist Howard Browers, it is time to take

the final counts of the year.

- Any idea what they are?

- The ducks? - Yeah.

- It's probably a combination of Pintail, Green-winged Teal.

- This is a pretty neat time to be on the refuge

during the fall migration.

I actually did a count just a couple of days ago,

and on this unit, we probably had close to 40,000 birds,

mostly ducks.

In another six weeks or so, the refuge will be frozen

and then pretty much everything is gone.

The resource we are trying to manage for

is the amazing waterbird, particularly resource shore birds

that use the Bear River and the Great Salt Lake ecosystem.

All of these birds depend greatly on the

Great Salt Lake ecosystem for not only breeding

but for feeding during migration

and the Bear River is a significant part of that.

For man, as well as for the wildlife,

fresh water is a scarce and coveted resource.

The priority is rarely given to the lake's ecosystem.

- In the spring, when irrigation season kicks in,

our water right becomes junior to the irrigators.

And irrigators get to take what they need from the river

and then we basically get what's left over.

And so, some of our wetland units can actually dry up

in the late summer.

90 percent of the water

from the Bear River is intercepted

and diverted into artificial canals

used to irrigate farmlands.

Millions of liters that never make it to the lake.

- All this diversion that's been going on

has consequences for the lake in that

the lake has been kinda going,

I wouldn't say steadily down,

it still has its ups and downs when we have

wet periods and dry periods, but overall,

along that 150 year period, the lake's been declining.

The misfortunes of

the Great Salt Lake are not all due to agriculture.

Urban development is also to blame.

Salt Lake City is steadily growing.

If the city keeps expanding at its current rate,

the population of the region will hit nearly three million

in ten years' time.

This demographic growth and its accompanying

industrial and agricultural development

considerably increase water needs

to the detriment of the Great Salt Lake.

- When I met the lake, it was much larger

than it is today, and you've seen the lake

going from very high to very low,

and we could do very serious and potentially

catastrophic damage by not allowing water to the lake.

The Great Salt Lake

struggles to strike an elusive balance

between the needs of man and those of nature.

It is winter once more, and the great migrations

are drawing to a close.

Indifferent to the coming cold, a colony of

10,000 tundra swans flocks along the lake's shores.

The bald eagle, legendary bird of prey and

symbol of the United states, sets up its winter quarters

on the Great Salt Lake.

The first snowfalls have capped the surrounding mountains

with white, but the lake has barely changed.

It will only be partially covered by ice,

as its high salt content keeps its water from freezing.

Only certain areas along the shores sometimes freeze,

but rarely for long.

The lake's unfrozen water plays a huge role

in the heavy snowfalls in the surrounding mountains.

Researcher Jim Steenburgh discovered that these snows,

sometimes in the form of blizzards, are the result of

a unique meteorological phenomenon, the lake effect.

- Up here at Snowbird gets 500 inches of snow a year,

and some of that snow is produced

by the Great Salt Lake effect.

And the Great Salt Lake effect happens

when you get cold air.

Some of that snow is produced by the Great Salt Lake.

And sometimes during the winter time,

we get these cold air intrusions from the northwest.

They move over the Great Salt Lake.

The thermal shock between the cold air

from the north and the damp, warm air of the lake

creates spectacular snowfalls.

- It really is the heating of the lake

that drives these storms.

Because that heating destabilizes the atmosphere,

and it drives these land breeze circulations

that come from the opposing shorelines,

they converge and help trigger these lake effect storms.

Though slowed in winter,

the biological cycle of the Great Salt Lake continues.

Little by little, the lake takes on its

characteristic green hue once again.

It prepares for its next rebirth.

In a few months' time, a new cycle will begin.

The thick blanket of snow covering the mountains

will melt and add water to the lake.

The brine shrimp will be born again,

and the migrating birds, back once more,

will enjoy their feast.

The Great Salt Lake, little known and often unpopular,

will once more prove that, in reality, it is the

generous protector of an immense biodiversity.