How a fleet of wind-powered drones is changing our understanding of the ocean | Sebastien de Halleux

171,488 views ・ 2018-12-11

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We know more about other planets than our own,
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and today, I want to show you a new type of robot
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designed to help us better understand our own planet.
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It belongs to a category
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known in the oceanographic community as an unmanned surface vehicle, or USV.
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And it uses no fuel.
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Instead, it relies on wind power for propulsion.
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And yet, it can sail around the globe for months at a time.
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So I want to share with you why we built it,
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and what it means for you.
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A few years ago, I was on a sailboat making its way across the Pacific,
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from San Francisco to Hawaii.
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I had just spent the past 10 years working nonstop,
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developing video games for hundreds of millions of users,
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and I wanted to take a step back and look at the big picture
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and get some much-needed thinking time.
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I was the navigator on board,
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and one evening, after a long session analyzing weather data
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and plotting our course,
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I came up on deck and saw this beautiful sunset.
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And a thought occurred to me:
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How much do we really know about our oceans?
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The Pacific was stretching all around me as far as the eye could see,
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and the waves were rocking our boat forcefully,
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a sort of constant reminder of its untold power.
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How much do we really know about our oceans?
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I decided to find out.
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What I quickly learned is that we don't know very much.
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The first reason is just how vast oceans are,
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covering 70 percent of the planet,
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and yet we know they drive complex planetary systems
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like global weather,
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which affect all of us on a daily basis,
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sometimes dramatically.
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And yet, those activities are mostly invisible to us.
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Ocean data is scarce by any standard.
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Back on land, I had grown used to accessing lots of sensors --
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billions of them, actually.
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But at sea, in situ data is scarce and expensive.
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Why? Because it relies on a small number of ships and buoys.
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How small a number was actually a great surprise.
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Our National Oceanic and Atmospheric Administration,
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better known as NOAA,
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only has 16 ships,
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and there are less than 200 buoys offshore globally.
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It is easy to understand why:
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the oceans are an unforgiving place,
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and to collect in situ data, you need a big ship,
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capable of carrying a vast amount of fuel
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and large crews,
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costing hundreds of millions of dollars each,
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or, big buoys tethered to the ocean floor with a four-mile-long cable
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and weighted down by a set of train wheels,
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which is both dangerous to deploy and expensive to maintain.
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What about satellites, you might ask?
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Well, satellites are fantastic,
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and they have taught us so much about the big picture
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over the past few decades.
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However, the problem with satellites
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is they can only see through one micron of the surface of the ocean.
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They have relatively poor spatial and temporal resolution,
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and their signal needs to be corrected for cloud cover and land effects
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and other factors.
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So what is going on in the oceans?
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And what are we trying to measure?
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And how could a robot be of any use?
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Let's zoom in on a small cube in the ocean.
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One of the key things we want to understand is the surface,
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because the surface, if you think about it,
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is the nexus of all air-sea interaction.
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It is the interface through which all energy and gases must flow.
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Our sun radiates energy,
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which is absorbed by oceans as heat
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and then partially released into the atmosphere.
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Gases in our atmosphere like CO2 get dissolved into our oceans.
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Actually, about 30 percent of all global CO2 gets absorbed.
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Plankton and microorganisms release oxygen into the atmosphere,
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so much so that every other breath you take comes from the ocean.
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Some of that heat generates evaporation, which creates clouds
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and then eventually leads to precipitation.
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And pressure gradients create surface wind,
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which moves the moisture through the atmosphere.
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Some of the heat radiates down into the deep ocean
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and gets stored in different layers,
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the ocean acting as some kind of planetary-scale boiler
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to store all that energy,
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which later might be released in short-term events like hurricanes
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or long-term phenomena like El Niño.
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These layers can get mixed up by vertical upwelling currents
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or horizontal currents, which are key in transporting heat
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from the tropics to the poles.
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And of course, there is marine life,
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occupying the largest ecosystem in volume on the planet,
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from microorganisms to fish to marine mammals,
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like seals, dolphins and whales.
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But all of these are mostly invisible to us.
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The challenge in studying those ocean variables at scale
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is one of energy,
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the energy that it takes to deploy sensors into the deep ocean.
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And of course, many solutions have been tried --
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from wave-actuated devices
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to surface drifters
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to sun-powered electrical drives --
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each with their own compromises.
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Our team breakthrough came from an unlikely source --
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the pursuit of the world speed record in a wind-powered land yacht.
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It took 10 years of research and development
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to come up with a novel wing concept
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that only uses three watts of power to control
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and yet can propel a vehicle all around the globe
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with seemingly unlimited autonomy.
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By adapting this wing concept into a marine vehicle,
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we had the genesis of an ocean drone.
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Now, these are larger than they appear.
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They are about 15 feet high, 23 feet long, seven feet deep.
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Think of them as surface satellites.
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They're laden with an array of science-grade sensors
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that measure all key variables,
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both oceanographic and atmospheric,
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and a live satellite link transmits this high-resolution data
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back to shore in real time.
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Our team has been hard at work over the past few years,
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conducting missions in some of the toughest ocean conditions
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on the planet,
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from the Arctic to the tropical Pacific.
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We have sailed all the way to the polar ice shelf.
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We have sailed into Atlantic hurricanes.
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We have rounded Cape Horn,
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and we have slalomed between the oil rigs of the Gulf of Mexico.
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This is one tough robot.
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Let me share with you recent work that we did
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around the Pribilof Islands.
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This is a small group of islands deep in the cold Bering Sea
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between the US and Russia.
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Now, the Bering Sea is the home of the walleye pollock,
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which is a whitefish you might not recognize,
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but you might likely have tasted if you enjoy fish sticks or surimi.
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Yes, surimi looks like crabmeat, but it's actually pollock.
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And the pollock fishery is the largest fishery in the nation,
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both in terms of value and volume --
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about 3.1 billion pounds of fish caught every year.
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So over the past few years, a fleet of ocean drones
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has been hard at work in the Bering Sea
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with the goal to help assess the size of the pollock fish stock.
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This helps improve the quota system that's used to manage the fishery
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and help prevent a collapse of the fish stock
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and protects this fragile ecosystem.
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Now, the drones survey the fishing ground using acoustics,
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i.e., a sonar.
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This sends a sound wave downwards,
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and then the reflection, the echo from the sound wave
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from the seabed or schools of fish,
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gives us an idea of what's happening below the surface.
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Our ocean drones are actually pretty good at this repetitive task,
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so they have been gridding the Bering Sea day in, day out.
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Now, the Pribilof Islands are also the home of a large colony of fur seals.
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In the 1950s, there were about two million individuals in that colony.
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Sadly, these days, the population has rapidly declined.
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There's less than 50 percent of that number left,
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and the population continues to fall rapidly.
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So to understand why,
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our science partner at the National Marine Mammal Laboratory
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has fitted a GPS tag on some of the mother seals,
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glued to their furs.
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And this tag measures location and depth
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and also has a really cool little camera
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that's triggered by sudden acceleration.
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Here is a movie taken by an artistically inclined seal,
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giving us unprecedented insight into an underwater hunt
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deep in the Arctic,
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and the shot of this pollock prey
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just seconds before it gets devoured.
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Now, doing work in the Arctic is very tough, even for a robot.
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They had to survive a snowstorm in August
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and interferences from bystanders --
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that little spotted seal enjoying a ride.
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(Laughter)
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Now, the seal tags have recorded over 200,000 dives over the season,
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and upon a closer look,
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we get to see the individual seal tracks and the repetitive dives.
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We are on our way to decode what is really happening
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over that foraging ground,
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and it's quite beautiful.
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Once you superimpose the acoustic data collected by the drones,
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a picture starts to emerge.
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As the seals leave the islands and swim from left to right,
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they are observed to dive at a relatively shallow depth of about 20 meters,
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which the drone identifies is populated by small young pollock
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with low calorific content.
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The seals then swim much greater distance and start to dive deeper
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to a place where the drone identifies larger, more adult pollock,
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which are more nutritious as fish.
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Unfortunately, the calories expended by the mother seals
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to swim this extra distance
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don't leave them with enough energy to lactate their pups back on the island,
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leading to the population decline.
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Further, the drones identify that the water temperature around the island
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has significantly warmed.
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It might be one of the driving forces that's pushing the pollock north,
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and to spread in search of colder regions.
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So the data analysis is ongoing,
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but already we can see that some of the pieces of the puzzle
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from the fur seal mystery
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are coming into focus.
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But if you look back at the big picture,
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we are mammals, too.
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And actually, the oceans provide up to 20 kilos of fish per human per year.
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As we deplete our fish stocks, what can we humans learn
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from the fur seal story?
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And beyond fish, the oceans affect all of us daily
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as they drive global weather systems,
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which affect things like global agricultural output
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or can lead to devastating destruction of lives and property
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through hurricanes, extreme heat and floods.
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Our oceans are pretty much unexplored and undersampled,
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and today, we still know more about other planets than our own.
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But if you divide this vast ocean in six-by-six-degree squares,
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each about 400 miles long,
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you'd get about 1,000 such squares.
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So little by little, working with our partners,
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we are deploying one ocean drone in each of those boxes,
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the hope being that achieving planetary coverage
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will give us better insights into those planetary systems
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that affect humanity.
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We have been using robots to study distant worlds in our solar system
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for a while now.
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Now it is time to quantify our own planet,
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because we cannot fix what we cannot measure,
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and we cannot prepare for what we don't know.
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Thank you.
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(Applause)
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