The effects of underwater pressure on the body - Neosha S Kashef

翻译人员: Ruoxin Zheng 校对人员: Gabriella Hu

当一条鱼从深海被钓上来的时候，

Sometimes when a fish is reeled up to the surface

它看起来像膨胀了一样。

it will appear inflated,

with its eyes bulging out of their sockets

不仅眼睛会从眼眶里突出来，

and its stomach projecting out of its mouth,

胃也会从嘴巴里出来，

as if its been blown up like a balloon.

就像一个被吹鼓的气球。

This type of bodily damage, caused by rapid changes in pressure,

这些症状通常是因气压快速变化而产生，

is called barotrauma.

称作气压伤。

Under the sea, pressure increases by 14.7 pounds per square inch

在水下，每下潜33英尺（约10米），

for every 33 foot increase in depth.

每平方英寸的压力就会增加14.7磅。

So, take the yelloweye rockfish,

拿黄眼石斑鱼举例，

which can live as deep as 1800 feet,

它可以生活 在1800英尺（约550米）的水下，

where there's over 800 pounds of pressure on every square inch.

这里的压强可以达到800磅每平方英寸，

That's equivalent to the weight of a polar bear balancing on a quarter.

相当于一只北极熊站在一枚硬币上。

Now, Boyle's gas law states

波义耳定律描述的是气体的规律，

that the volume of a gas is inversely related to pressure.

它讲的是气体体积与其压强成反比。

So, any air-filled spaces, like a rockfish's swim bladder,

所以像石斑鱼的鱼鳔 或人类的肺部，

or human lungs,

这类充满气体的器官，

will compress as they descend deeper

在个体下潜的时候会被压缩，

and expand as they ascend.

而上浮的时候会随之膨胀。

After a fish bites a fisherman's hook and is quickly reeled up to the surface,

所以当鱼上钩并且快速浮向水面的时候，

the air in its swim bladder begins to expand.

鱼鳔内的空气会随之膨胀。

Its rapid expansion actually forces the fish's stomach out of its mouth,

快速的膨胀会将它的胃部从口腔推出，

while the increased internal pressure pushes its eyes out of their sockets,

同时，持续增长的内部压强 会将眼睛顶出眼眶，

a condition called exophthalmia.

医学上称之为突眼。

Sometimes rockfish eyes will even have a crystallized appearance

有时石斑鱼的角膜还会气肿，

from corneal emphysemas,

在角膜内部生出许多小气泡，

little gas bubbles that build up inside the cornea.

这使得眼睛看起来很像结晶。

Thankfully, a scuba diver doesn't have a closed swim bladder to worry about.

幸好潜水员们没有鱼鳔， 自然不用担心这种问题。

A diver can regulate pressure in her lungs by breathing out as she ascends,

在潜水员上升时， 她可以通过呼气来调节肺部的气压。

but must be wary of other laws of physics that are at play under the sea.

但仍要考虑其他在深海中 会发挥作用的物理定律。

Henry's law states that the amount of a gas that dissolves in a liquid

亨利定律说，气体在液体中的溶解度…

is proportional to its partial pressure.

是与它的分压成比例的。

The air a diver breathes is 78% nitrogen.

潜水员呼吸的气体有78%是氮气。

At a higher pressure under the sea,

在深海高压的环境下，

the nitrogen from the air in a scuba tank

这时从氧气筒吸入的氮气…

diffuses into a diver's tissues in greater concentrations than it would on land.

…在体内的溶解度比在陆地时高。

If the diver ascends too quickly,

如果潜水员上浮速度过快，

this built up nitrogen can come out of solution

溶于体内的氮气会从溶液中跑出，

and form microbubbles in her tissues, blood and joints,

并在组织、血液和关节处形成微小的气泡。

causing decompression sickness, aka the bends.

从而造成减压病， 英文俗称为“the bends”。

This is similar to the fizz of carbon dioxide coming out of your soda.

就像打开可乐会冒泡一样，

Gas comes out of solution when the pressure's released.

气压降低， 液体中的气体就会被释放出来。

But for a diver, the bubbles cause severe pain

但对潜水员而言， 这些气泡会带来剧烈的疼痛，

and sometimes even death.

有时甚至会造成死亡。

Divers avoid falling victim to the bends by rising slowly

他们通过减缓上浮速度 来预防患上减压病，

and taking breaks along the way, called decompression stops,

又或者在上浮的过程中稍作休息， 即减压停留。

so the gas has time to diffuse back out of their tissues

因此，气体有足够的时间 扩散出组织，

and to be released through their breath.

并通过呼吸排出。

Just as a diver needs decompression,

就像潜水员需要减压一样，

for a fish to recover, it needs recompression,

鱼类需要再增压才能够康复。

which can be accomplished by putting it back in the sea.

简单的办法就是把它们送回大海。

But that doesn't mean that fish should just be tossed overboard.

但这并不意味着 直接把它们扔回海里，

An inflated body will float

膨胀的鱼会漂浮于水面，

and get scooped up by a hungry sea lion or pecked at by seagulls.

从而被海鸥，海豹等天敌吃掉。

There's a common myth

大家还有一个常识性的误区，

that piercing its stomach with a needle will let air escape,

就是用针扎破鱼的胃部来放气，

allowing the fish to swim back down on its own.

能使鱼可以自己游回栖息地。

But that is one balloon that shouldn't be popped.

但这个气囊可万万不该戳破。

To return a fish properly to its habitat,

要将鱼放回家园，

fisherman can use a descending device instead

捕鱼人可以用一个缓降器，

to lower it on a fishing line and release it at the right depth.

用鱼线将鱼下放到合适的深度后再放生。

As it heads home and recompression reduces gas volume,

在鱼回家时， 再增压使鱼体内气体的体积减少。

its eyes can return to their sockets and heal,

眼睛会回到眼眶内， 突眼症痊愈，

and its stomach can move back into place.

胃部也会回到原位。

This fish will live to see another day,

这条鱼将能再见到第二天的太阳，

once more free to swim, eat, reproduce and replenish the population.

并能自由地游泳、吃喝与繁衍下去。