The Ocean Conveyor - The "bloodstream" of the Earth

What is the ocean conveyor?

Sometimes known as the Thermohaline circulation, the ocean conveyor is basically a transportation system (current) within the oceans of the whole Earth. There are two main types of stages in the conveyor - deep water current (cold) and the surface current (warm).

Where is it?

It is located entirely in the ocean and it travels around the whole world. It has three main downwelling sites (where the surface water current goes into the deep water current) which are located in polar regions, and has two main upwelling sites (where the deepwater current turns into surface water current) which are in the Pacific and Indian ocean.

What is its function?

It keeps the ocean's temperature constant, distributes oxygen throughout the oceans and even on land (so basically distributes oxygen around the whole world), and also keeps some coastlines' temperature constant. It is relied on by almost all marine life and a lot of land life too, without it, many eco-systems would not be able to exist.

Why is it so important?

It is the 'bloodstream' of life, it provides the right temperature and oxygen for eco-systems all over the world, without it then the world would end up very different.

How is Global Warming affecting it?

As we know of, global warming is increaing the temperature of the Earth's atmosphere and is having a huge impact on the polar regions. The polar regions are where the downwelling sites are, so the temperature needs to be low enough so that the water can cool and sink deeper into the ocean and go down the deep water current route. However, global warming will eventually raise the temperature to a point where it is too warm for the water to sink and will therefore cause a halt in the ocean conveyor.

What will happen if the ocean conveyor stops?

If the ocean conveyor stops, then there will be nothing to distribute oxygen around the ocean and nothing to sustain the oceans temperature, so almost all marine life and eco-systems dependant on the ocean conveyor will die off.

Will anything happen to land life?

Yes, and it would be an even bigger problem. The stagnant (still) waters lacking in oxygen would provide a perfect home for anoxic bacteria (e.g. purple sulfur bacteria), which gives off hydrogen sulphide gas, a colorless, toxic, highly flammable gas that reeks of rotten eggs and flatulence (the production of gasses in the digestive tract). This would be released into the air and would be circulated around the Earth through the convection currents in the atmosphere (wind currents and directions). This would kill off almost all land living animals, plants and other life that respirate using oxygen (this is happening in some stagnant lakes and swamps but on a low scale, e.g. Green Lake, NY)  Apart from that, coastal temperatures will change which will cause mroe inland temperatures to change more drastically.

Has this ever happened before?

Yes, it has happened several times in the passed where it has wiped out most life and evolution had to "restart". This is evident in the geology of the Earth where in some areas there are layers of sedimentary rock (rock formed by compression of organic or chemical material (in this case - organic)) that are from when this happened. The rock differs in colour as it was formed quicker than other sedimentary rocks as the death rate was the highest ever.

How can we stop this from happening?

The only way to stop this from happening is to stop global warming. But as there are different theories on how global warming is caused and if it's human or natural, I'm leaving the descision to you.