Monday, April 19, 2010
Life on Earth is supported by a complex web of differing, but intergated mechanisms. One such mechanism is that of the Ocean Conveyor (also known as the Thermohaline circulation). The Ocen Conveyor is a mechanism whereby the ocenic water circulates through various parts of the Earth. This circulation is influenced by the density of water (in turn determined by the temperature and salt content of the water), the fresh water fluxes and the wind driven surface currents.
How does the Ocean Conveyor Work?
Let’s visualize the Earth as one big containor. In this container, waters of different temperatures exist at different places (thanks to the presence of the ice caps at the Polar Regions at one place, and that of the Equator at the other). This difference in temperatures (along with other factors – salt content and Air currents) triggers certain movements:
– The cold water dives to the ocean floor and the hot water comes to the surface
– The cold water is then propelled toward the hotter regions (near the Equator), there it becomes hot and rises to the surface;
- The hot water is, in its turn, propolled toward the colder areas – in the process it gets cold and dives to the ocean floor.
This cycle keeps repeating itself. The result is that every drop of water in the ocean completes a world tour once in every 5000 years!
Why is the Ocean Conveyor Important to Life on Earth?
1. It aids temperature management across the planet. It brings heat to the colder regions ( and vice versa)
2. It supports the life of more than 5000 species of marine Phytoplanktons.
Phytoplanktons are responsible for about 50% of the Photosynthetic activity that takes places on the Earth; thus, around 50% of all oxygen generated on Earth is produced by the Phyto Planktons. The Phytoplanktons depent to a great extent on minerals found near the ocean bed. The Ocean Conveyor (through its alternate diving and rising motions) performs the crucial role of supplying minerals to the phytoplanktons;
3. It circulares Oxygen, generated by the phytoplankton, throughout the planet.
What will happen if the Ocean Conveyor Stops?
Biologists opine that stoppage of the Ocean Conveyor was one of the biggest factors resonsible for the Permian Mass extintion (PME). The PME, which took place 251.4 Million years ago, is one of the 20 known mass extinctions to have occurred on Earth – infact, the biggest of them all. 96 % of all marine life, 70% of the terrestiral vertebrate life became extinct.
This occurred, among the others, because of the dramatic decrease in the amount of ice on Earth. Decreased ice slowed down the ocean conveyor significantly. A slowed ocean conveyor couldn’t generate enough oxygen and couldn’t circulate minerals – phytoplanktons died and the ocean food chain took a massive hit as a result of this; the level of photosynthesis and oxygen in the ocen reduced drastically – as a result – 96% of marine life came to an end.
Stangating water, reduced oxygen, huge amount of dead marine matter lead to a mass secretion of Hydrogen Sulphite – which took a huge toll on the terrestrial life – wiping 70% of it off.
What effect does Global Warming have on the Ocen conveyor?
Consumption of fossil fuels (emission of Greenhouse Gases) and deforestration have lead to a steadily increasing Global temperature. Increased temperature, among the other things, leads to a reduction of the volume of ice on Earth – in from of glacial retreat, shrinkage of the Greenland Ice sheet, Arctic shrinkage. This is a viscious cycle – Ice radiates a good amount of heat away from the Earth – The Albedo Effect; Reduced Ice, thus, in its turn, leads to higher temperatures.
What can we do?
Studies by the Climate commission indicate that even if the Greenhouse gases were to be retained at the year 2000 level, temperatures shall still continue to rise, as a result of thermal inertia of the oceans. Thus, there are two things that we need to control immediately: deforestration and emission of greenhouse gases.
Efforts are on throughout the globe to create awareness amongst people. To start using cleaner fuels, to plant trees, to reduce usage of paper, reduce reliance of fossil fuels, to create alternative greener fuels – fuels that will stem the greenhouse effect and promote sustainability. The International community; the Governments, the scientists and the Courts across the world have started actively promoting the green culture.
Around 97 to 99% of all the species that have ever lived on Earth have become extinct – for some reason or the other. Global warming has the potential to have a major disruptive effect on the Ocean conveyor and thus become a reason for extinction of Humans from the Earth.
The Green wave has started to flow across our planet, but, all said and done, we do rely heavily on fossil fuels, and may continue to do so in the near future. What the Earth awaits is the one major technological breakthrough… and the onus of bringing about that breakthrough rests on our civilization.