地球的力量 第4集 海洋（24）:大洋輸送帶

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

它被稱為是大洋輸送帶 它是地球上最大的能量之一

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

它由表面流動的溫暖洋流

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

和海洋底部較冷的洋流組成

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

輸送帶連接了整個地球它將氧氣養(yǎng)分和熱量運輸?shù)绞澜绺鞯?/p>

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

它是地球所有生命賴以生存的關(guān)鍵

Vet the conveyor wouldn't keep flowing

但是如果沒有寒冷的北邊海洋

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

輸送帶就會中止流動

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

在那里表面水體下沉與深海洋流混合

The sinking happens because the water's very cold.

下沉是因為水很冷

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 所以它就會沉入海底

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

就是這些下沉的水維持著整個輸送帶

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

在全世界流動 它向東流，深入海床知道在熱帶溫度增加后

where it eventually rises to complete the circuit.

它又上升完成循環(huán)