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

水中壓力對身體的影響 - Neosha S Kashef

譯者: Huan-Yu Hsieh 審譯者: Marssi Draw

Sometimes when a fish is reeled up to the surface

當魚被釣上水面時，

it will appear inflated,

有時會呈現充氣狀態，

with its eyes bulging out of their sockets

眼睛凸出眼窩，

and its stomach projecting out of its mouth,

而且胃從口部翻出，

as if its been blown up like a balloon.

就像吹氣球一樣。

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

這種肢體損傷是 因為壓力變化過劇造成，

is called barotrauma.

叫做「氣壓性傷害」。

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

在海裡，每下降 33 英呎，

for every 33 foot increase in depth.

壓力就會增加 14.7 磅力/平方英寸。

So, take the yelloweye rockfish,

拿銼頭平鮋來說，

which can live as deep as 1800 feet,

牠們可在深達 1800 英呎的地方生活，

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

那裡的壓力超過 800 磅力/平方英寸。

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

相當於一隻北極熊站在 一個兩角五分硬幣上。

Now, Boyle's gas law states

再看看波以耳定律：

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

氣體的體積和壓力成反比關係。

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

因此任何充氣的空間， 譬如像平鲉的魚鰾，

or human lungs,

或是人類的肺，

will compress as they descend deeper

下降越來越深時會壓縮，

and expand as they ascend.

上升時會膨脹。

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

一隻魚咬到漁夫的魚鉤， 然後迅速被拉到水面，

the air in its swim bladder begins to expand.

魚鰾裡的空氣就會開始膨脹。

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

快速膨脹將魚的胃從口中擠出，

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

而內部壓力增加 則把眼睛推出眼窩，

a condition called exophthalmia.

這種狀況稱為「眼球突出症」。

Sometimes rockfish eyes will even have a crystallized appearance

有時平鲉的眼睛 甚至出現結晶化的樣子，

from corneal emphysemas,

這是角膜氣腫的關係，

little gas bubbles that build up inside the cornea.

角膜裡面產生小氣泡。

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

幸好，潛水員不用擔心 封閉的魚鰾，

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

潛水員一邊上升時可以 藉由呼吸調整肺裡面的壓力，

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

但還是要注意其他 海裡的物理定律。

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

亨利定律說， 溶解在液體裡的氣體量

is proportional to its partial pressure.

和其分壓成正比。

The air a diver breathes is 78% nitrogen.

潛水員吸入的空氣 包含 78% 的氮氣，

At a higher pressure under the sea,

在海裡的高壓中，

the nitrogen from the air in a scuba tank

氧氣筒中的氮氣

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

在潛水員組織的分布 比陸地上的濃度大。

If the diver ascends too quickly,

如果潛水員上升太快，

this built up nitrogen can come out of solution

氮氣會從溶液中跑出來，

and form microbubbles in her tissues, blood and joints,

然後在她的組織、血液 和關節中產生微小氣泡，

causing decompression sickness, aka the bends.

導致減壓症，也就是潛水夫病。

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

就像你汽水裡的二氧化碳氣泡。

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

當壓力降低時， 氣體會從溶液中跑出來。

But for a diver, the bubbles cause severe pain

但是對潛水員來說， 氣泡會導致劇烈疼痛，

and sometimes even death.

有時甚至導致死亡。

Divers avoid falling victim to the bends by rising slowly

潛水員為了避免成為 潛水夫病的受害者，

會慢慢上升，中間停下來休息， 叫做潛水减壓站，

and taking breaks along the way, called decompression stops,

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

讓氣體有時間 從他們的組織散出，

and to be released through their breath.

再藉由呼吸釋出身體。

Just as a diver needs decompression,

就像潛水員需要減壓，

for a fish to recover, it needs recompression,

一隻魚如果要復原， 則需要加壓，

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

把牠放回海裡就可以了。

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

不過這不表示可以 把魚直接丟到船外。

An inflated body will float

充氣的身體會在水面漂浮，

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

然後被飢餓的海獅一下撈走， 或是被海鷗叼走。

There's a common myth

有個很普遍的傳說，

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

說只要用針刺一下魚胃放氣，

allowing the fish to swim back down on its own.

就可以讓魚自己游回去。

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

但這個「氣球」可不能戳。

To return a fish properly to its habitat,

要讓魚好好地回到棲息地，

fisherman can use a descending device instead

漁夫可以用一個下降裝置，

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

用魚線慢慢下降， 再在適當的深度放開。

As it heads home and recompression reduces gas volume,

等魚回家之後， 加壓減少了氣體體積，

its eyes can return to their sockets and heal,

牠的眼睛就可以 回到眼窩內然後復原，

and its stomach can move back into place.

牠的胃也可以回到原處。

This fish will live to see another day,

這隻魚就可以繼續過牠的生活，

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

重新游水、覓食、繁殖， 繁衍更多後代。