DK全球视觉Knowledge Encyclopedia Ocean知识百科全书深海

DK 2020新书 Knowledge Encyclopedia Ocean! 海洋知识百科全书（新增第8本）

OCEAN SCIENCE
海洋科学
Earth’s oceans are almost as old as the planet itself. Formed more than four billion years ago, they have been evolving ever since. Their waters are constantly on the move – flowing in currents around the globe, pulled in a daily cycle of tides, and rising and falling as waves that crash on the shores.
地球的海洋几乎和地球本身一样古老。它们形成于四十多亿年前，此后一直在进化。它们的海水不断流动——在全球范围内以洋流流动，以每天的潮汐周期拉动，并随着海浪拍打海岸而涨落。

OCEAN WATERS
海水
The vast majority of the planet’s water is contained within the oceans, filling these huge basins up to several kilometres deep. Ocean water is salty – in contrast with the fresh water found in rivers and lakes – and varies in temperature around the globe, from the balmy tropics to the freezing poles. Water continually moves between the oceans, air, and land, in the global water cycle.
地球上绝大多数的水都存在于海洋中，填满了这些数公里深的巨大盆地。海水是咸的——与河流和湖泊中的淡水形成鲜明对比——从温暖的热带到冰冻的两极，全球各地的温度都不同。在全球水循环中，水在海洋、空气和陆地之间不断流动。

HOW MUCH WATER?
多少水？
Seen from space, Earth’s vast expanses of water give it its nickname – the blue planet. More than 1.3 billion cubic km (300 million cubic miles) of salty water covers most of Earth’s surface.
从太空看，地球广阔的水域给它起了一个绰号——蓝色星球。超过13亿立方公里（3亿立方英里）的咸水覆盖了地球的大部分表面。
The average ocean basin extends to depths of around 6km (3.7miles) in depth. Compared to this, all other water sources, such as rivers, lakes, and inland seas, only hold very small amounts.
平均海盆深度约为6公里（3.7英里）。与此相比，所有其他水源，如河流、湖泊和内海，所含水量非常小。

WHY IS THE OCEAN BLUE?
为什么海洋是蓝色的？
Water is colourless and transparent, so sunlight can penetrate through it. But the sunlight we perceive as white is actually a mixture of all the different colours of the rainbow.
水是无色透明的，所以阳光可以穿透它。但是我们认为白色的阳光实际上是彩虹所有不同颜色的混合物。
Each colour can penetrate to different depths. Blue light can get much deeper than the others, travelling down to 100m (330ft), which is why the sunlit part of the ocean appears blue. But below this, no light can penetrate, so at deeper depths the ocean looks dark.
每种颜色可以渗透到不同的深度。蓝光可以比其他光线更深，传播到100米（330英尺），这就是为什么阳光照射的海洋部分看起来是蓝色的。但是在这下面，没有光线可以穿透，所以在更深的海洋看起来很暗。

WHAT IS WATER?
什么是水？
Water is made up of molecules far too small to see, even with the most powerful microscope. There are more than a thousand million trillion of them in a single drop.
水是由太小以至于用最强大的显微镜也看不见的分子组成的。在一滴水中就有超过1万亿个。
Each molecule of water is made up of a single oxygen atom and two hydrogen atoms joined by strong chemical bonds.
每一个水分子由一个氧原子和两个氢原子组成，两个氢原子通过强化学键连接在一起。

SALTY WATER
咸水
On average ocean water contains about 35g (1.2oz) of salt in every litre (2pints). This salt is made up of a mixture of chemicals. More than 80 per cent of salt is made up of just two types of chemical called sodium and chloride.
海水平均每升（2分）含盐约35克（1.2盎司）。这种盐是由多种化学物质的混合物组成的。超过80%的盐是由两种叫做钠和氯的化学物质组成的。
These make up sodium chloride – the salt we use for flavouring food. But ocean salt also contains other chemicals, in smaller amounts.
这些组成了氯化钠——我们用来给食物调味的盐。但海盐中也含有少量的其他化学物质。

HOT AND COLD SEAS
冷热海洋
Ocean temperature varies around the globe. Heat from sunshine is more intense in the areas around the equator, so the ocean’s surface is warmer there and gets colder towards the poles.
海洋温度在全球范围内变化。赤道周围地区的阳光热量更为强烈，因此那里的海洋表面更温暖，而两极则更冷。
But oceans everywhere get cooler with depth too and the water at the ocean floor is always cold, even at the tropics.
但是，任何地方的海洋也随着深度的增加而变冷，海底的水总是很冷，即使在热带地区也是如此。

THE WATER CYCLE
水循环
Since Earth was formed 4.5 billion years ago, the amount of water it contains has stayed about the same. However, this water constantly moves around and constantly changes state – between liquid, gaseous vapour, and solid ice.
自从地球在45亿年前形成以来，它所含的水量一直保持不变。然而，这些水在液态、气态和固态冰之间不断地流动和改变状态。
This process is called the water cycle and is driven by the Sun. Water evaporates from the ocean surface due to the Sun’s warmth and eventually falls as rain, which then returns to the oceans
这一过程称为水循环，由太阳驱动。由于太阳的温暖，水从海洋表面蒸发，最终以雨的形式落下，然后返回海洋

OPEN OCEAN
公海
More than 80 per cent of the inhabitable areas of our planet is the open ocean – deeper waters away from the shallow coastal seas.
地球上80%以上的可居住区域是公海——远离浅海的较深水域。
From its sunlit surface to its cold, dark floor, the open ocean is home to some of the most extraordinary animals known to science.
从阳光普照的海面到冰冷黑暗的海底，公海是一些科学界已知的最非凡动物的家园。

THE OPEN OCEAN
公海
The majority of the ocean’s water stretches beyond the coastal seas of the continental shelves, and reaches down to the deepest parts of the ocean basins – an area called the open ocean.
大部分海洋的水延伸到大陆架的沿海海域之外，并延伸到海洋盆地的最深处——一个被称为公海的区域。
This is the single biggest habitat on Earth and contains more living things than anywhere else on the planet. But conditions at the surface are very different from those at the bottom.
这是地球上最大的栖息地，比地球上其他任何地方都含有更多的生物。但地表条件与底部条件大不相同。

A drop in the ocean A huge variety of life forms can be found in just a single drop of seawater, from plant-like algae to the ocean’s tiniest herbivores and hunters.
海洋中的一滴一滴海水中就可以发现各种各样的生命形式，从植物状藻类到海洋中最小的食草动物和猎人。
These living things make up the plankton – the community of ocean drifters that are carried along with the currents because they are either too small or too weak to swim against them. Plankton exist everywhere in open water, but are richest near the surface, where sunlight provides the energy for algae to make food.
这些生物构成了浮游生物——海洋漂流者的群落，它们随波逐流而来，因为它们要么太小，要么太弱，无法逆流而上。浮游生物在开阔水域随处可见，但在水面附近最为丰富，阳光为藻类提供了制造食物的能量。

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