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Let’s say you wanted to make yourself a white, sandy beach.
如果你想要白色的沙滩。
You know, like the ones in Hawaii or islands in the South Pacific where people take luxurious vacations and lots of Instagram photos.
就像是夏威夷或南太平洋小岛那样的沙滩，大家尽情享受奢华的假期、拍照发Ins。
It turns out, the recipe for that picturesque white sand is pretty simple. There are a couple steps involved, but just one main ingredient: poop.
事实上，那种独特的白色沙滩的配方非常简单。只需几步，但是其中最主要的配方是——便便。
The first thing you’ll need is a coral reef — it’s location-specific and unfortunately there’s no store-bought alternative.
首先，你需要的是珊瑚礁——对珊瑚礁进行定位，糟糕，在商店里可买不到珊瑚礁。
Coral reefs are made up of thousands of tiny polyps, which are squishy sacs with tentacles that can sting and catch prey. Kind of like sea anemones.
珊瑚礁是由微小的珊瑚虫组成，珊瑚虫是一群带息肉的黏糊糊的囊，它们的触脚可以钉刺并抓住捕食。有点像海葵。
These polyps are anchored to a sturdy skeleton that they make by laying down a crystallized form of calcium carbonate called aragonite, which is a bright white color.
这些息肉会固定在坚固的骨架上，这些骨架是由被称为霰石的晶状碳酸钙搭成，呈明亮的白色。
Reefs are found in parts of the ocean that are considered to be oligotrophic —
在部分海洋中发现了被认为营养不良礁石——
which means that there aren’t that many tasty nutrients floating around, like phosphate or nitrate. And coral polyps aren’t exactly mobile,
这意味着海洋中没有足够的美味营养物，如磷酸盐或硝酸盐。而且珊瑚虫是不可移动的，
so if they were left to their own devices, they might starve. But coral polyps aren’t alone.
因此，如果它们离开了它们的巢穴，可能会被饿死。但是珊瑚虫也不是没有战友。
They get help from an algae called zooxanthellae that live symbiotically in their tissues.
它们可以向一种被称为黄藻的藻类求救，黄藻与珊瑚虫共生于它们的组织中。
These algae can photosynthesize, changing sunlight, carbon dioxide, and water into food energy,
这些藻类可以产生光合作用，能将阳光、二氧化碳及水变成食物能量，
and share a large chunk of that energy with the coral. As coral polyps get more energy, they build out their skeletons and grow the reef.
并与珊瑚虫共享这些能量。当珊瑚虫获得充足的能量后，它们开始建造自己的骨架并生长出暗礁。
And these algae are also what give coral its bright colors.
也正是因为这些藻类，珊瑚虫才能拥有明亮的颜色。
When you have a thriving coral reef, other undersea plants and animals move in and begin to form a whole ecosystem.
当你有了一个茂盛的珊瑚礁后，其他的海底动植物会移居到此珊瑚礁内，整个生态系统开始形成。
And to get your white sandy beach, you need some parrotfish, or more specifically... their poop.
要想得到白色沙滩，你还需要一些鹦嘴鱼或者更具体地说...你需要它们的便便。
Parrotfish get their name for their bright colours and their weird, bird-like beaks.
鹦嘴鱼因它们绚丽的颜色和像鸟一样怪异的嘴而得名。
These beaks are actually made of fused teeth called dental plates, which help them graze for their main food source: algae.
事实上，它们的鸟嘴是由一种被称为牙板的融合牙组成，能帮助它们寻找它们主要的食物来源：藻类。
Parrotfish spend their days scraping away at coral reefs, eating polyps for the zooxanthellae inside, and any other algae they can find.
鹦嘴鱼整天都围在珊瑚礁附近，想要刮掉并吃掉黄藻里边的息肉，或是吃掉任何它们可以找到的藻类。
They’re not super careful or picky, so they end up swallowing mouthfuls of calcium carbonate, too… which they can’t digest for nutrients or energy.
它们并不挑食，因此在吃到满满一嘴的碳酸钙后，它们会停止捕食，虽然它们无法消化其中营养和能量。
But the parrotfish have a secret weapon — their throats are hiding another set of teeth called pharyngeal jaws that can grind up the coral skeletons.
但是鹦嘴鱼有一个秘密武器——在它们的喉咙中隐藏着另一套被称为咽颌的牙齿，能够磨碎珊瑚的骨骼。
Like, the xenomorph from Alien… but in real life. This makes it easier for the chunks to travel through their digestive system.
就像是《异形》中的异形人来到现实生活一样。这套牙齿使得它们的消化系统能够更加容易的接纳大块食物。
And they get rid of this calcium carbonate in streams of the purest, whitest tropical sand.
然后它们会将这些碳酸钙排泄到纯净的、最洁白的热带沙流中。
In fact, according to some studies, one parrotfish can poop out around 300 kilograms of sand or more in a single year!
事实上研究表明，一只鹦嘴鱼一年内能排泄将近300千克的沙子甚至更多！
After some ocean currents stir everything around, you have yourself a pristine white sand beach.
当一些海流将所有东西搅拌之后，你就可以得到最原始的白色海滩了。
Perfect for strolling, sunbathing, and building sandcastles… as long as you don’t mind fish poop.
散步、日光浴、堆沙堡...完美，只要你不嫌弃这些鱼便便。
Thanks for watching this episode of SciShow, brought to you by our patrons on Patreon.
谢谢观看这一期的科学秀，谢谢提问的Patreon观众。
If you want to help support this show, you can go to patreon.com/scishow. And don’t forget to go to youtube.com/scishow and subscribe!
如果你支持这个栏目，请登录patreon.com/scishow。不要记得去youtube.com/scishow订阅我们哟~
