Name: 大堡礁的白化現象和寨卡病毒的最新進展 (Bleaching in the Great Barrier Reef, and a Zika Update)
Uploaded: 2021-01-14T06:05:32.000Z
Duration: 4 min 17 s
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Imagine scuba diving around the corals of Great Barrier Reef.

You are now probably picturing vibrant colors and a bustling ecosystem.

But if you decided to visit right now, you’d mostly be seeing the whitish skeletons of

Last week, the Australian Coral Bleaching Task Force announced that they’d completed

aerial surveys of about 4000 kilometers’ worth of reefs near Australia and Papua New

Out of the 520 reefs they surveyed, all but 4 showed signs of coral bleaching.

Coral is the foundation of reefs that provide food and shelter for thousands of species,

from shrimp to sharks to sea turtles. It’s thought that about a quarter of all marine

life depends on the coral reefs in some way.

Coral is made of tiny transparent animals called polyps, with thousands of them in each

chunk. The polyps produce calcium carbonate -- a white mineral -- which forms intricate

But most coral can’t survive alone. To get the energy and nutrients they need to grow,

the polyps team up with algae called zooxanthellae.

The polyps provide a home and the basic ingredients the algae need to survive. Then, the algae

use sunlight and photosynthesis to convert these into more complex nutrients like sugars

These algae come in all kinds of different colors, which is why coral reefs are normally

But when conditions change -- like when the water temperature gets too high -- the coral

The algae leave, taking their bright colors with them and leaving behind those pale calcium

This year’s El Niño weather pattern, combined with global warming trends, raised the ocean

temperatures around the Great Barrier Reef -- which is what’s causing the bleaching.

Since June 2014, bleaching has been happening in coral reefs around the world, which is

why scientists are calling this a global bleaching event, the third ever recorded.

When the oceans cool again, the algae can often recolonize, reviving the coral.

But sometimes they can’t move back in. It’s too soon to tell how much long-term damage

there will be, but scientists are estimating that about half of the bleached corals will

The reefs can grow back, but they’ll need time, and waters that stay at the right temperature.

And as oceans continue to warm, the coral might not get that chance.

In slightly more positive news, scientists have discovered the 3D structure of the Zika

When we last talked about Zika, back in February, researchers didn’t know much about the virus

-- just that it might be responsible for the sharp increase in Brazilian babies born with

a neurological condition called microcephaly.

Since then, scientists have made some progress when it comes to understanding how Zika spreads,

And last week, a team at Purdue University in Indiana published the 3D structure of Zika

It looks kind of like a little pom-pom, or some kind of candy … it might even be cute

It’s also very colorful, but the virus itself, of course, doesn’t actually have those colors

-- they were added to the image to help show the different parts of its structure.

The researchers used a form of microscopy called cryo-EM, where they freeze the virus,

then shoot high energy electrons at it. By studying how those electrons get scattered

or absorbed, they were able to piece together a digital 3D model.

Knowing what Zika looks like in so much detail is an important step in figuring out how the

virus works -- and hopefully, how to protect people from it.

So, what does this little pom-pom tell us?

Zika’s surface looks roughly spherical, but it’s actually closer to an icosahedron

– like the D20 you’d use in games like Dungeons and Dragons.

The protein coating that forms the icosahedron protects the genetic material inside.

But researchers are especially interested in those red nodules, which are carbohydrate

Now, it’s not unusual for viruses to have something like this – it’s how they latch

But this little loop is very different from the loops on other viruses related to Zika,

So, studying these regions in particular could be critical in understanding how Zika affects

humans -- for example, the loops might be allowing Zika to infect different kinds of

Of course, knowing Zika’s structure doesn’t guarantee a cure or vaccine. But if we’re

going to fight something, it helps to know what it looks like.

Thanks for watching this episode of SciShow, which was brought to you by, you guessed it,

all of our patrons on Patreon. If you are one of those people, thank you very much.

If you want to be one of those people, you can go to patreon.com/scishow to help support

us. And don’t forget to go to youtube.com/scishow and subscribe!

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大堡礁的白化現象和寨卡病毒的最新進展 (Bleaching in the Great Barrier Reef, and a Zika Update)

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