we're surrounded by exotic creatures

我們被一些奇異的生物環繞

that are too small to see with the naked eye.

它們小到我們肉眼看不見

We usually imagine these microscopic organisms, or microbes,

我們通常將這些微生物想像成

as asocial cells that float around by themselves.

獨自四處漂流的不合群細胞

But in reality, microbes gather by the millions

但事實上，微生物以數百萬計聚集

to form vast communities known as biofilms.

形成巨大的群落，稱為 生物薄膜 (biofilms)

Natural biofilms are like miniature jungles

天然的生物薄膜如同小型的叢林

filled with many kinds of microbes from across the web of life.

充滿許多生命網中各式各樣的微生物

Bacteria and archaea mingle with other microbes

細菌和古細菌與其他微生物混合

like algae, fungi, and protozoa,

如水藻、黴菌和原蟲

forming dense, organized structures that grow on almost any surface.

形成緻密、有組織的結構， 幾乎可以在任何表面生存

When you pad across a river bottom,

當你輕踏過河底

touch the rind of an aged cheese,

觸摸一塊陳年乳酪的外皮、

tend your garden soil,

照料花園的土壤

or brush your teeth,

或是刷牙

you're coming into contact with these invisible ecosystems.

你其實都在接觸這些看不見的生態系統

To see how biofilms come about,

欲了解生物薄膜如何產生

let's watch one as it develops on a submerged river rock.

那我們就來觀察一個長在河裡石頭 表面的生物薄膜

This type of biofilm might begin with a few bacteria

這種生物薄膜可能始於少數細菌

swimming through their liquid environment.

悠游於它們的液態環境

The cells use rotating flagella to propel towards the surface of the rock,

細胞運用旋轉鞭毛 推進朝向石頭的表面

which they attach to with the help of sticky appendages.

它們藉著粘性附屬物幫助附著上去

Then, they start producing an extracellular matrix

然後開始製造細胞外基質

that holds them together as they divide and reproduce.

當分裂複製時，它們會黏聚在一起

Before long, microcolonies arise,

不久之後，小菌落生成

clusters of cells sheathed in this slimy, glue-like material.

成群的細胞被包覆在 粘滑、膠狀物質中

Microcolonies grow to become towers,

小菌落長成塔狀

while water channels flow around them,

而且水道流繞其間

functioning like a basic circulatory system.

機能上像一個基本循環系統

But why do microbes build such complex communities

當微生物能獨自生存時， 為何要建造這樣複雜的群落呢？

when they could live alone?

首先，住在生物薄膜內的微生物

For one thing, microbes living in a biofilm

固定在一個相當穩定的微環境

are rooted in a relatively stable microenvironment

在此它們可以有營養來源

where they may have access to a nutrient source.

而且菌多較安全

There's also safety in numbers.

在外面暗黑的微生物野生世界

Out in the deep, dark wilderness of the microbial world,

孤立的微生物會面對嚴重危險

isolated microbes face serious risks.

掠食者要捕食它們、

Predators want to eat them,

免疫系統試圖毀滅它們

immune systems seek to destroy them,

而且還有許多有形的危險

and there are physical dangers, too,

例如缺水導致它們乾枯

like running out of water and drying up.

然而在生物薄膜中，細胞外基質

However, in a biofilm, the extracellular matrix

會保護微生物免於外在的威脅

shields microbes from external threats.

生物薄膜也使得個別細胞間能互動

Biofilms also enable interactions between individual cells.

當微生物緊密聚集在一起時

When microbes are packed against each other in close proximity,

它們能溝通、

they can communicate,

交換遺傳訊息

exchange genetic information,

並參與合作和競爭的社會行為

and engage in cooperative and competitive social behaviors.

以你花園的土壤為例

Take the soil in your garden,

那是數千種細菌的居所

home to thousands of bacterial species.

當一種細菌殖居於一株植物根部

As one species colonizes a plant root,

其個別細胞可能分化成 不同的次級種群

its individual cells might differentiate into various subpopulations,

各自執行一項特殊任務

each carrying out a specific task.

基質製造者會分泌細胞外粘性物質

Matrix producers pump out the extracellular goo,

游泳者製造纖毛 並可活動自如或遷徙

swimmers assemble flagella and are free to move about or migrate,

孢子產生者製造休眠、堅硬的內孢子 ──

and spore-formers produce dormant, tough endospores

可在飢餓、

that survive starvation,

極端溫度

temperature extremes,

和有害輻射線下倖存

and harmful radiation.

這種現象稱為 分工 (division of labor)

This phenomenon is called division of labor.

最後，產生一個高級精緻的合作系統

Ultimately, it gives rise to a sophisticated system of cooperation

本身有些像一個多細胞生物一樣

that's somewhat like a multicellular organism in itself.

但因為生物薄膜 常含有許多不同的微生物

But because biofilms often contain many different microbes

它們之間並無密切關聯

that aren't closely related to each other,

之間互動也可能是競爭的

interactions can also be competitive.

細菌對其競爭者發動猛烈攻擊

Bacteria launch vicious attacks on their competitors

藉著分泌化學物質進入周遭環境

by secreting chemicals into the environment,

或利用分子茅刺 將毒素注射到鄰近的細胞

or by deploying molecular spears to inject nearby cells with toxins

將它們漲破

that literally blow them up.

最終，競爭全都是為了資源

In the end, competition is all about resources.

假如一種細菌消滅了另一種

If one species eliminates another,

它就為自己保有更多的空間與食物

it keeps more space and food for itself.

雖然這生動的生命循環 超出我們的視力所及

Although this dramatic life cycle occurs beyond the limits of our vision,

但微生物群落 提供人類和其他物種有形的好處

microbial communities provide humans and other species with tangible,

有時甚至是美味可口的

and sometimes even delicious, benefits.

微生物構成地球上生物量 的一個主要部分

Microbes make up a major fraction of the biomass on Earth

而且在全球生態系統扮演一個重要角色

and play a critical role within the global ecosystem

它們供養所有較大型生物

that supports all larger organisms,

包括人類

including us.

它們製造了大量我們呼吸的氧氣

They produce much of the oxygen we breath,

而且被利用去清除環境汚染，如漏油

and are recruited to clean up environmental pollution, like oil spills,

或處理我們的廢水

or to treat our waste water.

更不用說，生物薄膜是我們享用的食物 普通與風味的要件

Not to mention, biofilms are normal and flavor enhancing parts

包括乳酪、

of many of the foods we enjoy,

義大利香腸

including cheese,

和紅茶菌

salami,

所以下次你刷牙、

and kombucha.

咬乳酪外皮、

So the next time you brush your teeth,

過篩花園土壤

bite into that cheese rind,

或丟河石掠過水面

sift through garden soil,

盡可能仔細看

or skip a river stone,

想像圍繞著你的微生物叢林

look as close as you can.

正等待被發現與探索

Imagine the microbial jungles all around you

waiting to be discovered and explored.