ABOUT THE SPEAKER
Melissa Garren - Marine biologist
Melissa Garren is a molecular and marine biologist with a passion for unlocking the mysteries of our ocean's ecosystems and finding new avenues for conservation.

Why you should listen

Melissa Garren studies marine microbes to better understand how pollution and climate change are destroying coral reefs and effecting our environment. Working under a fellowship from the Smithsonian Tropical Research Institute she began using molecular techniques to study microbial life in the ocean. At the Costa Rican wildlife refuge, Melissa helped spearhead a long-term monitoring project as well as educational initiatives. After recently receiving her Ph.D. in Marine Biology from the Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, she is now using microfluidic technology to understand the living ecosystem of coral reefs in a postdoctoral position at the Massachusetts Institute of Technology.

More profile about the speaker
Melissa Garren | Speaker | TED.com
TEDxMonterey

Melissa Garren: The sea we've hardly seen

Filmed:
243,926 views

An average teaspoon of ocean water contains five million bacteria and fifty million viruses -- and yet we are just starting to discover how these "invisible engineers" control our ocean's chemistry. At TEDxMonterey, Melissa Garren sheds light on marine microbes that provide half the oxygen we breathe, maintain underwater ecosystems, and demonstrate surprising hunting skills. (Apologies for the small audio glitches in this video.)
- Marine biologist
Melissa Garren is a molecular and marine biologist with a passion for unlocking the mysteries of our ocean's ecosystems and finding new avenues for conservation. Full bio

Double-click the English transcript below to play the video.

00:05
In the next ten minutes,
we will immerse ourselves
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in an amazing and beautiful marine world
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that's very often overlooked.
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I'd like to take you
on a journey into the sea,
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looking at it from the perspective
of its smallest inhabitants:
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the microbes.
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My goal is that after this short journey,
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you'll share my amazement
at how deeply connected our lives are
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to these microscopic creatures
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and also perhaps my concern
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that these relationships
are often neglected
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when it comes to making decisions
and policies about our oceans.
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When you look out on a clear blue ocean,
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you're actually gazing at
a microbial soup full of vibrant life.
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What you see here
are marine bacteria buzzing about
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and exploring other members
of the marine food web.
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To emphasize how small
this world really is,
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I've added a white line
to most of my slides
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that shows you the thickness
of a single strand of human hair --
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very tiny.
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An average teaspoon of clean seawater
has five million bacteria
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and 50 million viruses in it.
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If I were to scoop up
two gallons of seawater,
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there would be more bacteria
in those two gallons
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than there are people on this planet.
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Take just a moment and think about
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how many gallons might make up an ocean.
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Or maybe I've already made
your stomach turn,
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as you think of all of the seawater
we've each accidentally swallowed
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over the years.
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But luckily, we rarely get sick
from that seawater,
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because most marine microbes
are working for us,
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not against us.
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One of my favorite examples
is that they provide
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half of the oxygen we breathe.
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In middle school, we all learn
to thank the trees.
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And admittedly, they may be
more huggable than the microbes.
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But it turns out
that land plants only create
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a quarter of the oxygen we breathe.
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Another quarter comes
from macroalgae like kelp
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and a full 50% from the microbes.
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Take a deep breath in.
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Thank the trees.
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Take another deep breath in.
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Thank the macroalgae.
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Your next two breaths --
tip your hats to the microbes.
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This picture is of a bacterium
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that happens to be the single most
abundant photosynthesizer
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on our planet.
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It's called, "Prochlorococcus,"
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and this is oceans' oxygen-producing
powerhouse and, I might argue,
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one of the most amazing discoveries
of recent marine microbiology.
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We didn't know it existed until 1988.
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All of human history has depended
on this little microbe
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for the oxygen they breathe every day,
no matter where or when they lived.
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And we've only been aware
of that relationship for a mere 24 years.
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I find that astounding.
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How many more critical
relationships are out there
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that we have yet to discover?
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I see our relationship with marine
microbes as parallel in many ways
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to the relationship we have
with microbes in our gut.
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We've all experienced the wrath
of unhappy gut microbes
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at one point or another,
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perhaps food poisoning or tainted water.
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But we may be less aware of the connection
we have with marine microbes
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and the physical discomforts we can feel
when those communities change.
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As an extreme example: the disease
cholera is caused by a bacterium
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that thrives in the ocean.
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So while most marine microbes
are indeed helping us,
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there do remain plenty that are not.
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Our relationship with the ocean,
much like our gut,
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is dependent on the right
balance of microbes.
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The old phrase, "You are what you eat"
applies to our ocean microbes as well.
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To give you a sense of what
an overfed ocean may look like,
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here are two examples
of me sampling seawater.
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On your left, it's a clean coral reef,
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and on your right is
a nearly dead coral reef
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that has a very intense fish farming
operation in the waters there.
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You'll notice I'm only smiling
in one of these two pictures,
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and in the other one my dive buddy
had to be a whole lot closer
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to capture that image.
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So if we were to take a drop of seawater
from each of these samples
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and put it under the microscope,
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this is what the bacteria and viral
communities would look like.
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So again, clean reef on your left,
fish farm reef on your right.
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As we all have had a feeling of discomfort
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from imbalanced gut microbes,
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a fish swimming through
a part of the ocean
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that has been overfed in this way --
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in this case, by intense aquaculture,
but it could be a sewage spill
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or fertilizer runoff or any number
of other sources --
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that fish will feel
the physical discomforts
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of the ocean microbes being out of whack.
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There may be less oxygen present,
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there may be more pathogens there,
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and there may be toxins
produced by some of these microbes.
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The bottom line is that
from their tiny-scale existence,
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these tiny microbes have
a very large-scale power
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to control how our ocean smells,
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how it tastes,
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how it feels
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and how it looks.
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If you take one idea away
from my talk today, let it be this:
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we have an incredibly important
relationship with these marine microbes
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that have very large-scale consequences,
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and we're just barely
beginning to understand
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what that relationship looks like
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and how it may be changing.
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Just as a physician will have trouble
curing a disease of unknown cause,
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we will have similar trouble
restoring ocean health
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without understanding the microbes better.
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They are the invisible engineers
that control the chemistry of the ocean
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and therefore, what creatures
can live there,
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whether or not it's safe
for us to swim there
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and all of the other
characteristics we sense
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with our eyes, noses and taste buds.
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And the more we pay attention
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to these small but very numerous
members of the ocean,
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the more we're learning
they do indeed respond to human actions,
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such as in this fish farm example.
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Now, as the past few slides
about coral reefs may have suggested,
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I do indeed spend much
of my time as a researcher
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thinking about human-microbe interactions,
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specifically on coral reefs.
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It turns out,
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we're not alone in having
our own protective community of microbes.
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Corals, along with most other
organisms on this planet,
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have their own protective
communities as well.
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However, rather than keeping theirs
on the inside as we do in our gut,
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they keep theirs on the outside,
to protect them from their surroundings
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So what you're seeing here
is a three-dimensional image
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of a live spot on a living coral
with all of its living bacteria,
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that I took with some
exciting technology --
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a high-speed laser-scanning
confocal microscope.
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All of the red circles
are the symbiotic algae
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that live inside the coral tissue,
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turning sunlight and into sugars
they both can use,
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and all of the little blue dots
are the protective bacteria.
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So when I use image analysis software
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to highlight the outer layer
of the coral in white,
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you can see that there are still
some tiny little blue dots
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above that layer.
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And those bacteria are sitting
in a mucus layer,
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which is also part
of the coral's protective layer.
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From the bigger perspective,
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I spend my time thinking
about these relationships,
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because too many reefs are going
from looking like the picture on your left
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to the picture on your right.
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Believe it or not,
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the picture on your right remains
a very popular tourist snorkeling spot
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on the island of Maui,
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even though it's lost most of its coral
cover over the past decade or so.
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Corals are getting sick
all around the globe at alarming rates,
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and we really don't know how or why.
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I see the microbes on the coral reefs,
both the good ones and the bad ones,
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trying to link their micro-scale
behaviors to this big picture
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of: How do we help the reef
that looks like the right
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back towards something
that looks more like the left?
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Or: How do we stop
coral disease from spreading?
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Just over a year ago,
no one had ever seen a view like this.
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This video is a prime example
of making the invisible visible.
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We're looking at a side view
of the same coral as before,
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where the protective layer
meets the seawater;
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so, seawater on your right,
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coral on your left.
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It's incredibly exciting to me
that we can finally see these bacteria
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in real life, in real time,
at their micro scale,
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and learn how they interact
with the world around them.
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Ecologists all over the world
are used to being able
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to grab a pair of binoculars
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and go out and observe
what their study creatures do each day.
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But microbial ecologists
have desperately needed
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breakthroughs in technology,
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such as with this fast confocal,
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to make similar observations.
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I work to find ways that cutting-edge
technologies like this
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can help make the unseen seeable,
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to see marine bacteria in action
and learn how they behave.
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In doing so, we can learn how they respond
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to our actions and our behaviors
and the environment around them
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in ways that will help us
better manage our oceans.
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Another example of how I'm doing this
is by using microfluidics
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to study specifically how pathogens
behave in the ocean.
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The basic idea behind microfluidics
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is that you can use
nanofabrication techniques
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to recreate or mimic
the conditions bacteria experience
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at their own tiny scale in the ocean.
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What you see here is a microfluidic
chamber on a microscope slide
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with a microscope lens underneath it.
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We use high-speed video microscopy
to record bacteria behavior.
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The colored tubing is where
bacteria and seawater flow
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in and out of the device.
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And it's using a device like this
that I recently discovered
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that a known coral pathogen
actually has the ability
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to sniff around the seawater
and hunt for corals.
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Here's the video of in action.
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You'll see all of the pathogens
which are the tiny green dots on the left
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start detecting the coral mucus I put
on the right side of the channel,
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and they swim quickly
over in that direction and stay there.
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Up until now, it was thought
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that a pathogen would need some good luck
to find its host in the ocean.
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But simply by watching
and observing, we can learn
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that these bacteria are very well adapted
to seeking out their victims.
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These micro-channels are bringing
us closer than ever before
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to understanding how bacteria
navigate that big blue ocean.
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It turns out that this pathogen
can even detect the coral mucus
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when I dilute it 20,000 fold.
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So these bacteria are very well adapted
to hunting down these corals.
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I'm currently testing
different environmental conditions
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to see what scenarios make
this pathogen more or less capable
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of hunting corals.
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By learning more
about what triggers the hunt,
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we should be able to find ways
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to help slow down or prevent this disease.
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There's also some evidence
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that the healthy microbes on the coral
can fight off the pathogen
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if the conditions are right.
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So, one final image of a coral
and its healthy bacteria.
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I hope you've enjoyed this short journey
into our microbial oceans
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and that the next time you
look out at the sea,
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you'll take in a deep breath
of fresh ocean air and wonder:
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What else are all
of the unseen microbes doing
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to keep us and our oceans healthy?
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Thank you.
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Translated by TED Translators Admin
Reviewed by Camille Martínez

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ABOUT THE SPEAKER
Melissa Garren - Marine biologist
Melissa Garren is a molecular and marine biologist with a passion for unlocking the mysteries of our ocean's ecosystems and finding new avenues for conservation.

Why you should listen

Melissa Garren studies marine microbes to better understand how pollution and climate change are destroying coral reefs and effecting our environment. Working under a fellowship from the Smithsonian Tropical Research Institute she began using molecular techniques to study microbial life in the ocean. At the Costa Rican wildlife refuge, Melissa helped spearhead a long-term monitoring project as well as educational initiatives. After recently receiving her Ph.D. in Marine Biology from the Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, she is now using microfluidic technology to understand the living ecosystem of coral reefs in a postdoctoral position at the Massachusetts Institute of Technology.

More profile about the speaker
Melissa Garren | Speaker | TED.com