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鱼是怎么发电的?

How do fish make electricity? - Eleanor Nelsen

1800年 探险家亚历山大•冯•洪堡
In 1800, the explorerAlexander von Humboldt
看到一群带电的鳗鱼从水中跳出
witnessed a swarm of electric eelsleap out of the water
与迎面而来的马群抗争
to defend themselvesagainst oncoming horses.
许多人认为这个故事太离奇像是洪堡编造的
Most people thought the story so unusual that Humboldt made it up.
但是鱼类带电这个现象比你想象的还要常见
But fish using electricity is more commonthan you might think;
当然 带电的鳗鱼只是其中的一种 在水下
and yes, electric eels are a type of fish. Underwater,
光线很暗
where light is scarce,
电信号用来交流 航行
electrical signals offer waysto communicate, navigate,
并寻找 或是在极少情况下 电晕猎物
and find—plus, in rare cases, stun—prey.
大约有350种鱼具有可以产生和检测
Nearly 350 species of fishhave specialized anatomical structures
电信号的生理结构
that generateand detect electrical signals.
根据它们产生电的多少
These fish are divided into two groups,
这些鱼可以被分成两类
depending on how muchelectricity they produce.
科学家将第一组鱼称为弱电鱼
Scientists call the first groupthe weakly electric fish.
电器官离它们的尾巴很近
Structures near their tailscalled electric organs
它能产生一伏特的电
produce up to a volt of electricity,
电量大约是5号电池的2/3
about two-thirds as much as a AA battery.
电是怎么产生的呢?
How does this work?
鱼的大脑通过神经系统
The fish’s brain sends a signal
将信号传递到发电器官上
through its nervous system to the electric organ,
发电器官上布满了成千上万的
which is filled with stacks of hundreds
被称为发电细胞的碟状细胞
or thousands of disc-shapedcells called electrocytes. Normally,
一般情况下 发电细胞将钠离子与钾离子排出
electrocytes pump out sodiumand potassium ions
这样 外环境带正电 内部环境带负电
to maintain a positive charge outsideand negative charge inside.
但是当神经信号到达发电细胞
But when the nerve signal arrivesat the electrocyte,
它促使离子大门打开
it prompts the ion gates to open.
正电离子流回细胞
Positively charged ions flow back in. Now,
现在 发电细胞的外部的一侧呈负电
one face of the electrocyteis negatively charged outside
而内侧呈正电
and positively charged inside.
但是另一侧的电性正相反
But the far sidehas the opposite charge pattern.
这些变化的电性可以产生电流
These alternating chargescan drive a current,
将发电细胞变为生物电池
turning the electrocyteinto a biological battery.
这些鱼产生电的关键是
The key to these fish’s powers is
要协调好神经信号
that nerve signals are coordinated
使之同时到达每一个细胞
to arrive at each cellat exactly the same time.
这使得大量的发电细胞像一串由上千块电池连成的电池组
That makes the stacks of electrocytes act like thousands of batteries in series.
各处的微弱电量
The tiny charges
积攒起来 就形成了一个电场
from each one add up to an electrical field
可以扩散若干米的范围
that can travel several meters.
被称为电感受器的细胞藏在皮肤下
Cells called electroreceptorsburied in the skin
能使鱼连续感受到电场
allow the fish to constantly sensethis field
以及因环境或是其它鱼而改变的电场
and the changes to it caused by the surroundings or other fish.
比如 弯颌象鼻魚
The Peter’s elephantnose fish,for example,
具有被称为schnauzenorgan的延长下巴
has an elongated chincalled a schnauzenorgan
其中 布满了电感受器
that’s riddled in electroreceptors.
这使它可以从别的鱼那里截取信号
That allows it to intercept signalsfrom other fish,
判断距离 侦查附近事物的形状和大小
judge distances, detect the shape and sizeof nearby objects,
甚至还可以判断一个埋着的昆虫是死是活
and even determine whethera buried insect is dead or alive.
但是弯颌象鼻鱼和其它弱电鱼一样
But the elephantnoseand other weakly electric fish
不会产生足够的电去攻击猎物
don’t produce enough electricityto attack their prey.
那种能力属于强电鱼
That ability belongsto the strongly electric fish,
强电鱼只有那么几种
of which there are onlya handful of species.
带有最强大电力的鱼是 线翎电鳗
The most powerful strongly electricfish is the electric knife fish,
它也是最常见的电鳗
more commonly known as the electric eel.
三个发电器官几乎全分布在2米长的身上
Three electric organs spanalmost its entire two-meter body.
像弱电鱼一样
Like the weakly electric fish,
电鳗用它的信号来游动和交流
the electric eel uses its signals to navigate and communicate,
但是它储存超强的电量用于捕猎
but it reserves its strongestelectric discharges for hunting
利用双相攻击进行试探 之后捕猎食物 首先
using a two-phased attack that susses out and then incapacitates its prey. First,
它释放2-3个强脉冲
it emits twoor three strong pulses,
有600伏特
as much as 600 volts.
电流刺激猎物的肌肉 使之痉挛
These stimulate the prey’s muscles,sending it into spasms
产生电波使之暴露藏身之处 然后
and generating wavesthat reveal its hiding place. Then,
再快速地放出高电压的电流
a volley of fast,high-voltage discharges
导致即使再紧致的肌肉都会收缩
causes even more intensemuscle contractions.
电鳗还可以蜷缩起来
The electric eel can also curl up so
这样每个发电器官边缘形成的
that the electric fields
电场就会重叠起来
generated at each endof the electric organ overlap.
这个电流风暴最后使得猎物无法动弹
The electrical storm eventuallyexhausts and immobilizes the prey,
之后电鳗就可以吃活的食物了
and the electric eelcan swallow its meal alive.
另两个强电鱼是 能释放350伏特电的
The other two strongly electric fishare the electric catfish,
电鲶鱼
which can unleash 350 volts
它的电器官遍布身体绝大部分
with an electric organthat occupies most of its torso,
另一个是 电鳐鱼
and the electric ray,
它的头的两侧是肾状的电器官
with kidney-shaped electric organs on either side of its head
能产生220伏特的电
that produce as much as 220 volts.
世界上有一个关于发电鱼的谜题
There is one mystery in the worldof electric fish:
为什么它们不会让自己中招?
why don’t they electrocute themselves?
可能是因为强电鱼的体型大小
It may be that the sizeof strongly electric fish
允许它们承受它们的电量
allows them to withstand their own shocks,
或者是 流经它们身体的电流太快了
or that the current passes outof their bodies too quickly.
一些科学家认为 某些特殊的蛋白质可以保护发电器官
Some scientists think that specialproteins may shield the electric organs,
但是事实上 这也是目前科学未探明的谜题
but the truth is, this is one mystery science still hasn’t illuminated.

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译制信息
视频概述

列举了两类发电鱼 强电鱼和弱电鱼

听录译者

收集自网络

翻译译者

lala

审核员

审核员V

视频来源

https://www.youtube.com/watch?v=z0M7_HPSi14

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