Why didn’t this 2,000 year old body decompose? - Carolyn Marshall

1,778,559 views ・ 2021-02-04

TED-Ed


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翻译人员: Boya Li 校对人员: Jiasi Hao
00:06
In 1984, two field workers discovered a body in a bog outside Cheshire, England.
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1984 年,两名矿工在英国柴郡外的 林道沼泽里发现了一具尸体。
00:13
Officials named the body the Lindow Man
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官方将这具尸体 命名为林道人(Lindow Man),
00:15
and determined that he’d suffered serious injuries,
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并判定他曾受过重伤,
00:18
including blunt trauma and strangulation.
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包括钝性损伤和绞勒痕迹。
00:22
But the most shocking thing about this gruesome story
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但这段可怕的故事里最令人震惊的是,
00:24
was that they were able to determine these details from a body over 2,000 years old.
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人们能从一具两千多年前的尸体中 发现这些细节。
00:31
Typically, decomposition would make such injuries hard to detect
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一般来说, 即使是尸体下葬近有数星期,
00:34
on a body buried just weeks earlier.
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尸体腐化会使这些创伤难以察觉。
00:37
So why was this corpse so perfectly preserved?
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那么为什么这具尸体 保存如此完好?
00:40
And why don't all bodies stay in this condition?
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为什么并非所有的尸体 都能维持这一状态?
00:43
The answers to these questions live six feet underground.
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问题的答案 就在地面六英尺之下。
00:47
It may not appear very lively down here,
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地下乍一看很难发现生命的痕迹,
00:49
but a single teaspoon of soil contains more organisms
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但一茶匙土所含的微生物数量,
00:52
than there are human beings on the planet.
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比全球的人口都多。
00:55
From bacteria and algae to fungi and protozoa,
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从细菌、藻类到真菌、原生生物,
00:59
soils are home to one quarter of Earth’s biodiversity.
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土壤里生存着地球上 1/4 生物种类。
01:02
And perhaps the soil’s most important inhabitants are microbes,
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土壤里最重要的居民 或许是微生物,
01:07
organisms no larger than several hundred nanometers
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它们的大小仅有几百纳米,
01:10
that decompose all the planet’s dead and dying organic material.
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却能分解地球上 所有死亡或濒死的有机物。
01:15
Imagine we drop an apple in the forest.
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想象我们在森林里扔了一颗苹果,
01:18
As soon as it contacts the soil,
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它一旦接触到土壤,
01:20
worms and other invertebrates begin breaking it down into smaller parts;
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虫子等无脊椎动物便开始将其分解,
01:24
absorbing nutrients from what they consume and excreting the rest.
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一边吸收营养, 一边排泄废物。
01:28
This first stage of decomposition sets the scene for microbes.
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这是分解的第一步, 为后续的微生物分解做好了准备。
01:33
The specific microbes present depend on the environment.
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不同环境中 生存的微生物也有所不同。
01:36
For example, in grasslands and farm fields there tend to be more bacteria,
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比如,草地和田地里细菌较多,
01:40
which excel at breaking down grass and leaves.
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它们擅长分解草和树叶。
01:43
But in this temperate forest there are more fungi,
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但这片温带森林里的真菌更多,
01:46
capable of breaking down complex woody materials.
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它们能够分解结构复杂的木材。
01:50
Looking to harvest more food from the apple’s remains,
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为从苹果残骸里获得更多的食物,
01:53
these microbes release enzymes
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这些微生物开始释放生物酶,
01:54
that trigger a chemical reaction called oxidation.
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并导致氧化反应。
01:58
This breaks down the molecules of organic matter, releasing energy,
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这会分解有机物分子, 释放能量;
02:02
carbon, and other nutrients in a process called mineralization.
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而碳和其它营养物质 则会发生矿化作用——
02:06
Then microbes consume the carbon and some nutrients,
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微生物消耗碳和一些营养物质,
02:09
while excess molecules of nitrogen, sulfur, calcium, and more
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而剩余的氮、硫、钙分子等
02:13
are left behind in the soil.
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被留在土壤里。
02:15
As insects and worms eat more of the apple,
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随着昆虫和蠕虫进食更多苹果,
02:17
they expose more surface area for these microbial enzymes
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它们增加了苹果 暴露于这些生物酶的表面积,
02:21
to oxidize and mineralize.
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从而促进氧化和矿化反应。
02:23
Even the excretions they leave behind are mined by microbes.
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甚至是它们留下的排泄物 也会被微生物分解。
02:27
This continues until the apple is reduced to nothing—
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这一过程会持续到苹果消失——
02:30
a process that would take one to two months in a temperate forest.
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在温带森林里需要 1-2 个月时间。
02:34
Environments that are hot and wet support more microbes
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与干冷的地方相比,
02:37
than places that are cold and dry,
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湿热的环境适合微生物生存,
02:39
allowing them to decompose things more quickly.
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同时促使微生物加速分解进程。
02:42
And less complex organic materials break down faster.
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结构较为简单的有机物 分解速度较快。
02:46
But given enough time,
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但只要有足够的时间,
02:47
all organic matter is reduced to microscopic mineral nutrients.
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所有的有机物都会被分解为 微小的矿物营养物质。
02:52
The atomic bonds between these molecules are too strong to break down any further.
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这些分子的原子键合力很强, 无法被继续分解。
02:57
So instead, these nutrients feed plant life,
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于是,这些营养物质会滋养植物,
03:01
which grow more food that will eventually decompose.
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植物会长出更多最终能被分解的食物。
03:04
This constant cycle of creating and decomposing supports all life on Earth.
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这一创造和分解的链条不断循环, 养育地球上所有的生命。
03:11
But there are a few environments too hostile for these multi-talented microbes—
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但有些环境却令这些 能干的微生物难以适应——
03:16
including the peat bogs outside Cheshire, England.
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包括英国柴郡外的 那片泥炭沼泽。
03:20
Peat bogs are mostly made of highly acidic Sphagnum mosses.
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泥炭沼泽中 基本上都是强酸性的泥炭藓苔。
03:24
These plants acidify the soil while also releasing a compound
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这些植物会酸化土壤, 并释放出一种化合物。
03:28
that binds to nitrogen, depriving the area of nutrients.
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这种物质会与氮结合, 使土壤里的营养物质流失。
03:32
Alongside cold northern European temperatures,
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再加上欧洲北部的寒冷气候,
03:35
these conditions make it impossible for most microbes to function.
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这些条件 使得大部分微生物无法正常工作。
03:39
With nothing to break them down,
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由于没有微生物能将其分解,
03:41
the dead mosses pile up, preventing oxygen from entering the bog.
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枯死的藓苔逐渐堆积, 因此氧气无法进入沼泽。
03:45
The result is a naturally sealed system.
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结果形成了一个自然的密闭空间。
03:48
Whatever organic matter enters a peat bog just sits there— like the Lindow Man.
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任何进入泥炭沼泽的有机体 都会维持原样——
比如林道人。
03:55
The acid of the bog was strong enough
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沼泽所含的酸性物质足够强,
03:57
to dissolve relatively simple material like bone,
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能够溶解构造较为简单的物质, 比如骨头,
04:00
and it turned more complex tissue like skin and organs pitch black.
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并让皮肤、器官等结构复杂的组织 变成黑色。
04:04
But his corpse is otherwise so well-preserved,
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但除此以外, 他的尸体保存完好——
04:07
that we can determine he was healthy, mid-20s,
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我们能推断出他死前很健康。 年龄为 20 多岁,
04:10
and potentially wealthy as his body shows few signs of hard labor.
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可能生活富足,因为他的身体没有 太多从事强力劳动的痕迹。
04:14
We even know the Lindow Man’s last meal—
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我们甚至知道林道人最后一餐 吃了什么——
04:17
a still undigested piece of charred bread.
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一片还未消化的干面包。
04:21
Scholars are less certain about the circumstances of his death.
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学者们还不清楚他死亡的原因。
04:25
While cold-blooded murder is a possibility,
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或许他死于一场冷血的谋杀,
04:27
the extremity of his injuries suggest a ritual sacrifice.
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但尸体创伤的严重程度表示 他也可能作为献祭品死于祭祀。
04:32
Even 2,000 years ago,
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即便在两千年前,
04:33
there’s evidence the bog was known for its almost supernatural qualities;
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有证据表明,当时的人们认为 沼泽具有超自然力量——
04:38
a place where the soil beneath your feet wasn’t quite dead or alive.
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在那里,你脚下的土壤 并没有绝对的死亡与生命。
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