==JAPAN: KM== [Science]

The sea must become a savior of men in the 21st century. We have wasted the Earth's resources. We are using up the natural resources on the land. But we still have the vast expanse of the sea. The sea covers seven-tenths of the earth, but we have mapped only a small percentage of it. The sea contains huge quantities of minerals, millions of species of animals and plants which we have not identified. The sea is still the frontier. Recently the studies of the ocean are showing that the sea will probably make us happy in the future.
An alternative energy resource to oil is attracting international attention these days. It is methane hydrate. Methane hydrate is a crystalline solid consisting of methane, each surrounded by a cage of water molecules. It looks very much like ice. Methane hydrate is stable in ocean floor sediments at water depths greater than 300 meters. Methane hydrate was discovered only a few decades ago, and little research has been done on it until recently. By some estimates, the energy locked up in methane hydrate deposits is more than twice the global reserves of all conventional gas, oil, and coal deposits combined. The problem is no one has yet figured out how to pull out the gas from the bottom of the sea. But many researchers around the world are trying to find a good way of pulling it out now. We are going to use the energy of methane hydrate in the near future.
The marine resources are not only on the floor of the sea but also in seawater. Do you know that gold is held in solution in seawater? Seawater can dissolve a lot of kinds of substances like magnesium, uranium, silver, gold, and so on. It is said that all seawater across the globe has five gigatons of gold!! Its quantity is equivalent to the gold production in the world of two million years. But I'll tell you one thing. You had better not try producing gold from the seawater. It is because only about four milligrams of gold is included in 1000 tons of seawater, though it is extraordinary amount in the entire sea. If you bring water of as much as five times volume of Tokyo Dome to the boil, you get gold worth only 1500 yen. It is said Germany that was defeated in World War I tried to take out gold from seawater and use it for the ransom. However the cost of boiling seawater was so large that the plan could not be performed economically. Now we are taking out uranium effectively from seawater.
The sea is very useful in medical fields, too. We can get good medicines from some marine plants and animals. For example there is squalamine. It was discovered in 1993 in the stomach and liver of the dogfish, a type of shark. This substance shows promise for cancer therapy; clinical trials are about to begin with patients suffering from brain or breast cancers. The compound is believed to act by preventing blood vessels in the human body from obeying commands from cancer cells to link to them, so starving them of the blood supply that is essential for growth. One of the main hopes for this new drug is that cancers will fail to develop resistance to it because it doesn't act on the cancer cells themselves, but on the existing blood vessels. And this property of not attacking cancer cells themselves means this medicine has less side effect because it doesn't damage normal cells, either. Another example is an effective drug for AIDS which was found in horseshoe crabs. We have known much less about sea lives than lives on land. So we will be able to find better drugs in marine organizations.
As we have seen, the sea has much fortune for mankind. Men have prospered too much only on land. We haven't developed the sea yet and know too little about the appeal of the sea. Many scientists are starting to look at the sea these days. Some studies about the sea are achieving good results. In the 21st century, the vast sea will play a leading part and bring about further prosperity to the world.


"Getting It Together"

It is the first time that I have written such a long essay in English. So it was very difficult. I searched the uses of unknown words by using the Internet. Information obtained from the Internet was enormous. It was hard to select appropriate information from the huge volumes of information. I put in a lot of effort to write this essay. Please read this essay once.