WEBVTT

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DAISY: NASA engineers have
designed and built some amazing

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telescopes, satellites, and
space probes, looking out to

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the far regions of the Milky
Way and the universe...

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But some of the most important
things they monitor are right

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here. Looking back at us from
space, NASA's Earth Observing

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System is helping to preserve
our world's natural resources.

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Find out how, next on Real
World.

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? [music] ?

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DAISY: NASA's Earth Observing
System plays an important role

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in the recovery efforts of a
vital ecosystem,

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the Chesapeake Bay. The
Chesapeake is an estuary,

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a partially enclosed body of
water where freshwater mixes

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with the salt water of the sea.
The Chesapeake Bay is the

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largest estuary in the US,
stretching more than 300

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kilometers from the top of
Maryland to the Atlantic Ocean

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in Virginia.

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It holds about 57 trillion
liters of water and is the home

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of more than 3600 species of
wildlife.

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But human impact has changed
the Bay and it isn't as healthy

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as it once was. To better
understand those changes,

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bay managers monitor the
Chesapeake...

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and that's where NASA helps.

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The agency is using satellites,
like LandSat, MODIS and SeaWifs

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to keep an eye on the bay,
collecting data that scientists

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use to monitor its conditions.

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Scientists analyze the data to
understand the changes and

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predict what might happen in
the future.

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ERIC BROWN DE COLSTOUN: We
monitor satellite data over

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time to see how things are
changing

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DAISY: Eric Brown de Colstoun
is an associate Research

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Scientist with the University
of Maryland, Baltimore County.

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He works at NASA's Goddard
Space Flight Center.

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ERIC: We have to develop a big
mosaic of the Chesapeake Bay

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Watershed from LandSat, so we
take 22 different images that

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we have to stitch them
together, if you will...

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and that's kind of the base
data.

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DAISY: Four centuries of
population growth have crippled

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the bay, harming water quality
and threatening the species

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that rely on clean water for
survival. About half of the

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water in the Chesapeake Bay
comes from the Atlantic Ocean.

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The other half drains into the
Bay from its enormous

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watershed, a 165 thousand
square kilometer

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area that covers parts of six
states.

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ERIC: This image was put
together by hundreds of

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different images of LandSat.
We're trying to put together a

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mosaic of this whole region,
over time.

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DAISY: Most of the pollutants
in the bay come from the

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watershed. The watershed acts
like a huge funnel, collecting

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water from rain or snow melt.
Some of the water soaks into

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the ground; some becomes runoff
that collects contaminants as

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it drains downhill into the
waterways that feed the bay.

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Watershed runoff carries
pollutants from farms, suburban

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lawns and wastewater treatment
plants, into 5 major rivers,

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and eventually into the bay
itself.

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Eric studies the land cover in
this region.

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Land cover is the physical
material at the surface of the

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earth. Land cover like marsh
and forest is good for the bay.

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It acts as a filter, holding
the pollutants away from the

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water. Land cover like pavement
creates problems.

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The built up surface can
increase the strength of runoff

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into the streams, as well as
add pollutants.

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Polluted run off, from the
Chesapeake Bay's watershed

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causes Eutrophication.

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JACKIE HARMON: Eutrophication
is a process that ultimately

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diminishes oxygen levels in the
water.

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DAISY: Jackie Harmon is a
Virginia Oyster Restoration

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Specialist for the Chesapeake
Bay Foundation.

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JACKIE: What happens is, we
have excessive algae blooms

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that are generally fueled by
nitrogen that comes into the

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bay. Nitrogen, a lot of times,
is used as a fertilizer on the

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land, and it does the same
thing in the water that it does

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on the land. It makes plants
grow, and the specific plant

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that it really fuels growth for
in the bay is algae.

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DAISY: So the algae consume the
nitrogen, grow, and eventually

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die. The decomposition process
consumes oxygen in the water.

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JACKIE: That's a major issue
because the oxygen that the

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bacteria in the decomposition
process are using is the same

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oxygen that the fish and the
crabs and the oysters

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need to live.
DAISY: Water with a low

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concentration of dissolved
oxygen is called hypoxic.

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And hypoxic water is not a good
environment for wildlife.

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JACKIE: So it makes it very
difficult for other animals to

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survive in areas where there's
low oxygen, and ultimately it

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becomes referred to as a dead
zone.

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DAISY: And the delicate
ecosystem of the bay is

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changed. But with images from
NASA satellites, scientists and

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policy makers can identify land
cover and changes in land cover

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that contribute to runoff into
the bay.

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NASA, along with the US
Geological Survey,

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manages the LandSat satellite.
LandSat records pixels;

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small pieces of the earth's
surface just 30 meters by 30

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meters, when put together, give
an overall view of the bay.

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Scientists locate individual
pixels based on coordinates and

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latitude/longitude. Images can
be put together in a grid or

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coordinate system like you
might find on a road map.

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Scientists can compare the same
pixels over time,

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to measure changes in that
particular area.

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ERIC: There's another example
for Washington D.C. So you see

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Rock Creek Park, Greenbelt
Park. You see the Mall,

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I guess Hains Point, Andrews
Air Force Base.

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So you can actually see the
runways. And so what they've

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done is, they've actually
tracked this over time.

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And see where things, where the
urbanization has gone, as well.

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DAISY: This and other
information from NASA

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satellites help Chesapeake Bay
managers enact policies in very

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geographically specific
locations, to reduce toxic

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pollution, and improve water
quality.

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Both Maryland and Virginia use
data collected by LandSat to

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prioritize land conservation
actions.

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And the effect....

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Well, there's a long way to go.
The Chesapeake Bay Foundation

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has been measuring the health
of the bay since 1998.

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Each year, officials grade the
bay on a 100 point scale.

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A score of 100 would equal the
pristine state of the

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Chesapeake, as Captain John
Smith explored it upon arriving

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in the new world in the 1600s.

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The numbers correlate to a
letter grade, and while the

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scale's a little different,
it's not unlike the grade you

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might receive on a math or
science test.

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For the last few years, the bay
received a 28 - a D.

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JACKIE: Overall, the bay is
pretty sick. It's, it's not,

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it's not saved. We... We know
how to do it.

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It's going to take a lot of
action on the land as well as

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things done in the water, like
active restoration,

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but, we still have a ways to
go.

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DAISY: The foundation has set a
goal of reducing the amount of

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nitrogen pollution entering the
bay, by more than half,

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to 50 million kilograms per
year. That would be a huge

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step towards getting the bay
removed from the nation's dirty

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water list.

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So while the path to a
healthier, more productive

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Chesapeake bay is still long,

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NASA and its partners, through
satellite missions like LandSat

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and Sea Wif are helping to make
that journey possible.

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JACKIE: Listen all you all,
what I'm about to say.

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It's time to get together to
save this bay. With a creature

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that's been around for
thousands of millennia. It

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goes by the name of Crassostrea
Virginica. Some people eat

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Ďem. The bay really need Ďem.
They're chillin' under water

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cause they're filter feedin'.
There are so many cool things

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oysters do. There reefs are
habitat for an underwater zoo.

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With gobies , linis,
oyster-toed fish, crabs and
eels and

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worms and shrimp. You say you
have a hard time believin'

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this? You can trust me. I'm a
specialist. Go and spread this

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message all across the nation,
about a funky new science

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called oyster restoration.

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[music]

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