地球的力量 第4集 海洋（24）:大洋输送带

It's called the great ocean conveyor and it's one ofthe most powerful forces on the planet.

它被称为是大洋输送带 它是地球上最大的能量之一

It's made up of warm currents which travel at thesurface

它由表面流动的温暖洋流

whilst at the bottom of the ocean are much colder currents.

和海洋底部较冷的洋流组成

The conveyor transports oxygen, nutrients and warmth around the world.

输送带连接了整个地球它将氧气养分和热量运输到世界各地

It's vital to the health of all life on Earth.

它是地球所有生命赖以生存的关键

Vet the conveyor wouldn't keep flowing

但是如果没有寒冷的北边海洋

if it wasn't for what happens in the cold northern oceans.

输送带就会中止流动

This is where the surface water sinks to join the deep water currents.

在那里表面水体下沉与深海洋流混合

The sinking happens because the water's very cold.

下沉是因为水很冷

This makes it dense and heavy,so it plunges to the bottom of the ocean.

所以密度增加，重量加重 所以它就会沉入海底

And it's this sinking water which keeps the entire conveyor moving.

就是这些下沉的水维持着整个输送带

As ft travels south, ft hugs the ocean floor,until it warms at the equator,

在全世界流动 它向东流，深入海床知道在热带温度增加后

where it eventually rises to complete the circuit.

它又上升完成循环