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  • Born of fire, the Galapagos archipelago evokes visions of an ecological Eden. They are volcanic,

  • isolated islands, so they are unique. This primordial world is home to some of the strangest

  • creatures on earth -- from sea-going lizards to tortoises the size of rum barrels. This

  • is a special place where so many strange animals are living together. Penguins, mantas, sea

  • lions, sea iguanas. Altogether in one place. And this strange ecosystem has very interesting

  • behaviors. The islands are engulfed in cold and warm ocean currents, resulting in this

  • unique diversity of species. You get cold water organisms and warm water organisms all

  • mixed. Corals are among the warm water species living in the islands- and what is happening

  • to them may be a harbinger of things to come. We know now that the ocean chemistry is changing

  • dramatically and that's because of the industrial age and all of the carbon dioxide that has

  • been put into the atmosphere. Corals are forecast to be impacted severely by these changes in

  • ocean chemistry. The isolation of these islands makes them a perfect laboratory for studying

  • climate change. The Galapagos Islands acts as a natural laboratory because it's naturally

  • exposed to high c02 conditions that provide essentially a window into the future of what

  • we can expect throughout the rest of the world's oceans, with the doubling and tripling of

  • atmospheric c02. The other added benefit is that it has experienced two very strong El

  • Nino events in the last three decades. During El Niño warm seawater temperatures cause

  • coral bleaching. And coral bleaching is one of the primary concerns of what coral reefs

  • face with climate change. So by going into the Galapagos and studying how these reefs

  • respond to warmer temperatures under these naturally low pH conditions, we can gain a

  • window into the future. What is in store for coral reefs? Can corals survive in more acidic

  • oceans and cope with increased water temperatures? Major funding for this program was provided

  • by The Batchelor Foundation, encouraging people to preserve and protect America's underwater

  • resources. And by Divers Direct Emocean Club, inspiring the pursuit of tropical adventures

  • and scuba diving. Early Spanish explorers called them "Las Encantadas"

  • --"the Enchanted Islands." The Galapagos are located in the eastern Pacific,

  • about 600 miles off the coast of Ecuador. In 1835, Charles Darwin visited the archipelago,

  • calling it a "little world within itself." The strange creatures he encountered would

  • later shape his thoughts on the origins of life, and help him form his theory of evolution.

  • The Galapagos Islands is a really fascinating location. Because even Charles Darwin when

  • he visited noted how coral reefs were conspicuously absent from this location. Because the Galapagos

  • sits right on the equator. It's within the tropical belt. What really differentiates

  • it from the rest of the tropics is that you have this strong upwelling creating very different

  • conditions than what you find normally in the tropics. Upwelling is a physical process

  • whereby deep waters are brought to the surface. This deep water is rich in c02 and rich in

  • nutrients. And when it comes to the surface, it creates these low pH locations in the ocean.

  • This upwelling, as well as the confluence of several currents, results in the unique

  • life forms living in the Galapagos. For half the year, The Humboldt, or Peru current, brings

  • cold, nutrient rich waters up from Antarctica. From the west, the Cromwell current also brings

  • cold water. Around January, the trade winds shift and the Humboldt current slackens. Now

  • the Panama current dominates. The Panama Current flows south from the Panama and Colombia area,

  • and the Panama current brings tropical organisms into the Galapagos. What Darwin couldn't see

  • is that corals are among these tropical organisms. Now a team of around 20 scientists have arrived

  • onboard the M/Y Golden Shadow to study the health of these reefs. Supported by the Khaled

  • bin Sultan Living Oceans Foundation, they will spend a month in the Galapagos as part

  • of the five-year Global Reef Expedition. One of the biggest barriers to oceanographers

  • and ecologists to study remote areas of the oceans is just getting access to it. And the

  • Golden Shadow and the Living Oceans Foundation is very unique in that regard that we provide

  • scientists from around the world the access they need. The foundation was established

  • by Prince Khaled bin Sultan of Saudi Arabia, to conserve coral reefs around the world.

  • He knew that reefs are in trouble, and what he wanted was to set up a foundation that

  • would go out and answer some of the pressing questions about why coral reefs are dying

  • and what we can do to stop it. So he came up with this idea "Science without Borders"-it's

  • basically because there are no political boundaries between the oceans. It's all connected. And

  • what you do in one location, can affect another location. We go around the world to survey

  • these reefs. We're applying a standard protocol that was developed through a consortium of

  • scientists and we're applying that same survey protocol every place we go. We've developed

  • this model of cooperation where we invite researchers from around the world to come

  • on the ship and join us. And we're able to select researchers that have specific knowledge

  • about each region that we go to. One of the people joining them on this trip is longtime

  • Galapagos National Park naturalist and dive guide Mathias Espinosa. The Galapagos are

  • relatively new volcanic islands, formed less than five million years ago. And their history

  • is written into the rocks. Okay Philip, this is very interesting because this island is

  • an uplifted island that means that lava flowed to a place underwater, and with the pressure

  • of the plates that piece came out of the water. And you see some layers here, of white coral

  • that shows you there was a lava flow underwater and a long time of nothing but white coral

  • could grow on the lava flow. And then another lava flow over it. So it's very interesting

  • to see that there were times of lava flows then nothing, then another lava flow. And

  • so obviously these corals have existed in the Galapagos for thousands and thousands

  • of years for that layering effect to have happened. Yeah, definitely. I mean we're not

  • rich in corals, but it shows that we had the constant arrival of corals and growing up

  • to a certain point. I guess for thousands of years. One of the comments you hear all

  • the time is well, coral reefs have always undergone disturbance and change. And that's

  • absolutely true. The thing we're really concerned about is the frequency, the severity and the

  • duration of the changes all seem to be ramping up at scales that coral reefs have never experienced.

  • Now, scientists want to understand what the thresholds may be for corals to survive into

  • the future. Maybe you can try to anchor with a cut around

  • here. The strong currents near the islands can be dangerous to divers, so they consult

  • with local expert Mathias before their research dives.

  • Whatever the current is, don't let your people get into deeper water.

  • One way the experts study the corals is by measuring the currents that occur nearby.

  • So this right here is our current meter. And what we are going to do, we set it up and

  • then we are going to deploy it. The scientists want to correlate the strength of the currents

  • to the types of coral communities they find in an area, to better understand why certain

  • corals live where they do. Coral reefs that exist in the Galapagos really pale in comparison

  • to what you find in other parts of the world that have very high pH. There's a limited

  • subset of species that occur there, and they're very sparse in terms of spatial distribution.

  • There's very few coral reefs in the Galapagos islands. These corals weren't discovered until

  • the early 1970s. Dr. Peter Glynn was among the first to explore and study the reefs of

  • the islands. They were totally healthy. Very vibrant coral communities. All of the corals

  • looked in excellent condition. And so we thought that there would never be a problem there

  • - that coral reef development would continue into the future. But every so often the natural

  • balance between cold and warm ocean currents in this region goes awry. During El Nino years,

  • trade winds reverse direction, the cold life-giving waters of the Humboldt and Cromwell currents

  • dwindle, and warm waters devoid of nutrients flow in from the western Pacific and surround

  • the islands. And what happens is the surface waters warm considerably. And corals live

  • very near their upper thermal limits. And they're so sensitive that a deviation in sea

  • surface temperature of only one degree Celsius above the normal conditions for a month or

  • more, will elicit coral bleaching. A coral lives in a symbiotic relationship with algae

  • that live inside its tissues. And the algae photosynthesize and provide fixed carbon to

  • the coral host. And in turn the coral provides nutrients, a home that is free from predation.

  • However the symbiosis is very restricted into a very narrow thermal range. When temperatures

  • warm the corals will expel their symbiotic algae that live within their tissues. And

  • this is called coral bleaching. So the coral can live for a period without its symbiotic

  • algae, but it can't live for too long. So if the stress remains for a couple months

  • or more, corals will start dying. I think the El Nino phenomenon has occurred for several

  • thousands of years, and there was just no one around to observe the early events. But

  • in 1982-83, we had a very severe El Nino event. In the Galapagos, the coral mortality at our

  • study sites ranged anywhere from 95-97%. Very high. In 1997-98, there was another very strong

  • El Nino event. And some of the corals that weren't affected in 82-83, suffered mortality.

  • So we had two very strong events occurring just in one century. So this was very unusual,

  • and it had a tremendous impact on corals in the eastern pacific. On this research expedition,

  • scientists are going back to past study sites to see if the corals have recovered. In the

  • North, one species survived the second bleaching event better than the first. It seemed to

  • have adapted to the warmer temperature, which is a hopeful discovery for the team. We found

  • very substantial recovery in Darwin and Wenman. But very minimal recovery in the central and

  • southern Galapagos Islands. There's been coral bleaching events elsewhere that have killed

  • off all the corals. But what makes the Galapagos unique is that the entire reef framework itself

  • was actually completely bio-eroded in about 10 years. Other places usually the non-living

  • coral reef framework will persist over time much longer. The lack of recovery and bio-erosion

  • of the underlying reef framework likely are caused in part by the fact that pH is much

  • lower in the southern and central Galapagos. Derek measures the carbon dioxide, or Co2

  • levels, in the water around the islands. Research has shown that increased levels of cO2 in

  • the oceans will have devastating impacts on corals. The oceans act as a carbon sink for

  • atmospheric C02. So the oceans naturally equilibrate with the atmosphere over time. About 30 percent

  • of all the fossil fuel carbon dioxide, that's what we put in the atmosphere since the industrial

  • revolution, has been absorbed by the oceans, which actually raises the ocean's acidity

  • and lowers the ocean's pH. So this process is termed ocean acidification. The more acidic

  • it becomes the harder it is for coral to deposit its skeleton. The rate of change in ocean

  • pH that's occurring right now hasn't occurred in the oceans for at least the past 300 million

  • years. So what that means is that organisms and animals that live in the ocean are experiencing

  • a change in the environmental conditions at a rate that's greater than anything they've

  • seen, since prehistoric times. The Galapagos serve as the perfect natural laboratory to

  • study how corals will be affected by more acidic oceans. So the unique nature of the

  • Galapagos is such that the different islands have different pH conditions. Some areas of

  • the archipelago already experience double the amount of dissolved carbon dioxide in

  • the water compared to most regions where corals exist now.

  • These c02 conditions in the Galapagos basically approximate what we expect for the

  • rest of the oceans with ocean acidification at the middle or end of this century. To study

  • the coral calcification rates, Derek extracts cores from a species of coral that is common

  • in the Pacific. We used a pneumatic hand drill fit with a diamond coring bit at the end,

  • so we can attach this directly to a scuba tank.

  • And what this allows us to do is to take a sample down the main growth axis of the coral.

  • And corals lay down density bands, much in the same way that trees put down tree

  • rings. So every year, corals go through a natural oscillation in their skeletal density.

  • This process may look destructive, but its impact on the coral is similar to that of

  • a biopsy in a human. We take a cement plug or

  • use some coral rubble, that doesn't have anything living or growing on it. We plug up

  • the hole and then fix it with an underwater epoxy. And then the coral is able to grow

  • tissue right back over that that lesion within a few years. The overwhelming majority of

  • the time the coral isn't harmed from the sampling. Once back in the lab in Miami, Derek

  • analyzes the cores. So this is an example of a coral core we take out of a massive

  • coral skeleton. We cut it down and put it into our CT scanner. And then with that CT

  • scanner we can look at that coral core in three dimensions of the x

  • ray images which provides us a metric of the density of the core as you go down over

  • time and as you look at coral growth. So what we see here is an example of about 10

  • years of growth from a coral core, and you see these high density peaks that occur on

  • regular intervals. So that's associated with the annual high-density peak formation that

  • occurs in coral growths. So we use the distance between these peaks to get an

  • estimate of the annual growth rate of coral skeletons. And then once we have that data

  • of coral growth with time, we can understand how various disturbances or

  • environmental conditions like sea temperature may have impacted rates of coral growth.

  • What we see is that the calcification rates at the different regions vary considerably.

  • And as you increase in pH the calcification rates

  • also increase. Experts forecast that climate change will not only lead to ocean acidification,

  • but rising water temperatures will also lead to more frequent bleaching events. The

  • most recent research that's been done, has shown that globally all coral reefs are

  • going to begin experiencing annual bleaching events, somewhere around the year 2050. And

  • what we've learned in the Galapagos is that it only takes one coral bleaching event

  • to kill an entire reef and have that reef framework be completely eroded and you know

  • almost non-existent after 10 years. The combination of increased temperatures and

  • low pH are something we're just now beginning to understand the effects of on

  • coral reef ecosystems. There could potentially be a c02 tipping point in the Galapagos, at

  • which coral reefs are no longer able to recover from strong coral bleaching events.

  • The only coral reef in the entire Galapagos archipelago that has persisted and survived

  • the repeated coral reef bleaching events, has been in a place where pH is naturally

  • highest. As pH declines from that location, the

  • coral reefs there have not fared well at all, and have shown little resilience or recovery

  • from the warm water bleaching events. So this suggests that there could be a threshold

  • to coral reef resilience from thermal stress at some kind of c02 level. In other words,

  • as the pH of the oceans declines, coral reefs

  • will likely lose their ability to rebound from

  • warm water events and coral bleaching over time. So this is a very sobering future for

  • coral reefs based on how we expect the climate system to change.

  • The collection of scientific data underwater is serious business, but sometimes it is difficult

  • for the scientists to ignore the spectacular and unique wildlife that is all around them.

  • You definitely do see sea lions and they can impact your work because they are like

  • underwater puppies, and extremely playful. So they often times will swim away

  • with your gear when you're not looking. So you know it's not uncommon to see

  • someone swimming after a sea lion shaking their fist while doing work in the Galapagos.

  • Occasionally in the early days in the 70's when we were down there a penguin swam

  • over the corals, and so this was certainly something that you wouldn't see very often.

  • So that was pretty exciting. Another researcher along on the expedition

  • is Dr. Iliana Baums from Pennsylvania State University. Together

  • with one of her students, she has discovered a species of coral in the Galapagos

  • that was previously thought to occur only in Hawaii. It's very hard to distinguish

  • visually from the most common of the reef building species out here. The two species

  • look so much alike, the only way to tell them apart is by looking at their DNA in a lab.

  • To do so, and to understand how common the newly identified species is, the experts collect

  • coral samples in the field. The reason why we want to know how much we have of one

  • or the other species is because they interact with their environment very differently.

  • One of the species deals with climate change differently, so when waters get warm

  • one of the species bleaches more frequently than the other. If water temperatures

  • keep rising with climate change you might get one species to survive better

  • than the other, so there might be a shift in

  • the ecosystem in terms of what species it is composed of. Understanding this species

  • diversity is crucial for managers as they try to predict how reefs will respond to climate

  • change in the future. The four week expedition in the Galapagos

  • led to the collection of a large amount of data and new insights. Scientific

  • research is vital for the long-term survival of Galapagos. Ecuador has some resources.

  • But we need to have scientists from different parts of the world to

  • find out what is going on in this special ecosystem like Galapagos. And as more

  • scientific work is done it's a great help for Galapagos. I think the corals in the southern

  • and central islands are not showing any signs of recovery. So that is not encouraging.

  • But it's a reality. And we found that the reefs continue to recover in the northern

  • islands. So this is encouraging. We're certainly hopeful

  • this trend will continue. We know coral reefs are in trouble. But what we've seen

  • in a lot of these areas is they are amazingly resilient and they can rebound. And we know

  • that climate change is predicted to just get worse. But what our hope is, is that corals

  • can adapt to climate change. The Galapagos and its unique creatures are a symbol of adaptation,

  • having provided important clues about the way life evolves on planet Earth.

  • Now they may also serve as a window into the future -- providing a glimpse of how corals

  • may adjust to the drastic changes forecast to occur in the world's oceans.

  • Major funding for this program was provided by The Batchelor Foundation, encouraging people

  • to preserve and protect America's underwater resources. And by Divers Direct Emocean Club,

  • inspiring the pursuit of tropical adventures and scuba diving. And by the Do Unto Others

  • Trust.

Born of fire, the Galapagos archipelago evokes visions of an ecological Eden. They are volcanic,

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"ガラパゴス:未来への窓 "フルエピソード ("Galápagos: Windows into the Future" Full episode)

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    kevin に公開 2021 年 01 月 14 日
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