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What color is the ocean?

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Trick question.

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It's all kinds of colors.

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Blues, greens, reds,
yellows and swirls of all of the above.

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And these colors can tell us a lot about
what's going on just beneath the surface,

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what's thriving or changing,
or could pose a threat.

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For over 20 years, NASA has been looking
at the color of the ocean

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with technology
that's, well, over 20 years old.

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And that has taught us a lot
about the health of ocean ecosystems,

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but there are details we just can't see.

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Enter PACE, the Plankton, Aerosol,
Cloud, ocean Ecosystem mission.

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PACE’s new instruments

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will look at our world's oceans,
lakes and rivers in an entire rainbow's

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worth of color and beyond, giving us
new insights into marine communities,

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the carbon cycle and climate studies.

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So let's take a look at the top
five official best-ever

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ocean colors of all time.

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This is the open ocean.

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Here the oceans absorb the longer
red wavelengths and scatters the blues

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In these vast stretches of deepest blues
is where the tiniest of bacteria

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cycle
and recycle nutrients in microbial loops.

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For example, the tiniest
and most abundant,

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photosynthetic organism,
Prochlorococcus, converts carbon dioxide

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into organic compounds and forms
the base of the marine food web.

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These phytoplankton
are eaten by tiny zooplankton,

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and then eaten by larger zooplankton,
then smaller fish and so on,

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and then return the nutrients back
through respiration and remineralization,

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which are then
taken up by the tiny microbes.

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But here is where things are changing.

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These deep blues are getting greener
with a warming climate.

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But exactly how and why is unclear.

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Despite some scientific theories,
The past and present satellite

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sensors just don't have enough sensitivity
to color to tease that out.

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PACE will fill in those gaps with higher
spectral information, and slowly

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over time be able to discern the drivers
associated with these detected changes.

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This appealing brownish orange

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is the result of what's known as colored
dissolved organic matter.

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We can think of it as a kind of tea
that leaches out of dead or

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dying organic matter,
like the tannins from broken down leaves,

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giving the surrounding water
a darker, browner hue.

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Found in higher concentrations
in lakes, rivers, estuaries and marshes

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colored dissolved organic
matter is a great proxy for dissolved

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organic carbon,
a big pool of carbon in aquatic systems,

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and it's an indicator
of the health of an ecosystem.

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Much like a cloudy cup of tea,

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higher levels of this organic matter
don't let as much light through, changing

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the availability of light for plant-like
organisms in the environment.

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With PACE’s Ocean Color Instrument’s
hyperspectral measurements,

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even into the ultraviolet wavelengths,
we’ll be able to differentiate sources

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of this organic matter
and better understand

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the transfer of carbon
across land and into coastal regions.

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A grayish green in a large lake
like this could spell potential harm

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from a bloom of blue-green
algae known as cyanobacteria.

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Depending on the type and abundance,
cyanobacteria can spread

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toxins to aquatic and human life.

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In 2019,
Lake Erie saw a bloom of the Microcystis

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cyanobacteria form
a thick layer of scum filled with a toxin,

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which posed a major risk to drinkable
water.

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The Microcystin toxin can cause liver

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damage, dizziness, numbness and vomiting.

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Researchers are eager to use
the hyperspectral information from PACE in

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order to detect early stages of harmful
algal blooms, like the ones in Lake Erie.

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PACE will be able to measure the unique
optical properties of cyanobacteria,

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which will help separate the harmful
algae from other phytoplankton present

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in the water and allow resource managers
to monitor the health of freshwater.

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This turquoise
stretch tells us a lot about the sediment

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churning in the water,
and both the quality and quantity

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of that sediment
can have big impacts on marine life.

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For example, in Greenland,
glaciers can bulldoze over surface rocks,

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grinding them into a fine powder of silt
and clay, known as glacial flour.

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The glacial flour
changes the appearance of the water,

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with the particles absorbing the shorter
wavelengths, purples and indigos,

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and the water absorbing the longer
wavelengths, the reds and oranges.

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This sediment can bring nutrients
and fuel algal blooms,

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But if you're an oyster, sediments
could be a big problem.

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When lots of sediment is suspended
in the water, filter

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feeders like oysters can't feed as efficiently.

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And high sediment levels can be associated
with increased harmful Vibrio bacteria,

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which can cause sickness and even death
when those oysters are eaten.

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PACE’s hyperspectral

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measurements will see far more variability
in reflectance

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and give us better estimates of water,
clarity and particle size.

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And that data could be used
by oyster farmers monitoring

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the health of the shellfish population.

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As the days
grow longer in the subpolar regions,

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a milky swirly light blue hue
grows in the oceans.

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This is the telltale mark of coccolithophores--

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coccolithophores?

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Coccolithophores, a kind of phytoplankton

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that is completely covered
in a chalky shell of calcium carbonate.

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When these plankton bloom
and then die off,

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that inorganic chalky
material sinks to the ocean floor.

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PACE will better observe
these particular blooms,

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allowing researchers to account
for the amount of carbon coccolithophores

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remove from the atmosphere
and sink into the depths of the ocean.

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If all of these

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colors can tell us what's going on
with our ecosystems, our health,

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our climate, then PACE’s enhanced
resolution is going to reveal new levels

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of detail in how humans and water
are connected in a changing world.