Mariana Trench intro *** (original) (raw)
Wondering what this Mariana Trench is all about?
WHERE
The Mariana Trench is located north of New Guinea. About 250 miles (400 km) SW of Guam, which is part of the beautiful Mariana Islands. The Mariana Islands are the closest Pacific island chain to Japan (approximately 2,400 km from Tokyo). The island chain is 750 km long and Guam (U.S. Territory) is the southernmost island. The Guinness Book of Records cites the Northern Marianas as having the most equitable climate in the world, with an average year-round temperature of 85 degrees Fahrenheit (high twenties in °C).
The Japanese submersible Kaiko - sampling mud at the bottom of the Mariana Trench. (Photograph courtesy and copyright Dr. Hideto Takami, JAMSTEC.)
WHAT
The Mariana Trench is the deepest point on the Earth's surface. That makes people sometimes think it is like a pin hole, but the trench is more than 1,500 miles long (about 2400 kilometers) and on average 44 miles wide (nearly 70 kilometers).
The trench contains several deep points - called deeps - and the deepest of them all is the so-called Challenger Deep. It is located at about 11°22'N, 142°25'E. Some of the pictures on these pages show sediment samples being taken from the bottom of the Challenger Deep.
If you scan the literature, you will find various numbers for the depth of the Mariana Trench:
- In 1957, the R/V Vitiaz measured a depth of 10.990 m. This was later corrected to 11.034 m.
- The bathyscaphe Trieste determined the depth as 10.911 m, in 1960.
- A survey carried out in 1984 concluded that the depth was 10.924 m at 11°22.4'N, 142°35.5'E
- The R/V Hakuho Maru recorded a depth of 10.550 m in 1992 and that was later corrected to 10.933 m.
- Kaiko recorded depths of 10.898 m during dives in 1995 and 1996.
- A study decribed in a 2003 paper measured a depth of 10.744 m at 11°22.927'N, 142°26.258'E, but the authors of this article say that their calculation was not as accurate as that of the 1984 survey.
How do they do this? Well, it is a bit like listening for an echo in a large cave, or counting the seconds between a flash of lightning and the following thunder. You need to know how fast the sound travels to be able to calculate the distance. So what matters here is the velocity of sound in water. It varies with certain factors and one of them is depth. Pressure compresses the water and makes it denser.
The depth of the Challenger Deep boils down to:
- about 36,000 feet below sea level;
- which is about 6.8 miles down;
- and that equals about 11,000 meters;
- or 11 km.
That makes the Mariana Trench quite a few feet deeper than Mount Everest is high. If you look at other web sites and articles, you will also find several numbers for how high Mount Everest is. NASA currently gives it as 29,035 ft. or 8850 meters.
WHY
Check the Mariana Trench geology section for an answer to that question.
HOW
Pressure in the oceans increases with depth (hydrostatic pressure; hydro means water and static is something like standing). There are fishes and other organisms that live near the bottom of the Mariana Trench. At about 1,100 atmospheres pressure. How can organisms live at such depths? How do these organisms cope with such high pressures? The Mariana Trench biology section tells you more about it.
Deep-sea diving machines
Interested in the deep sea and diving machines? Check out the following sites:
- Alvin(Woods Hole Oceanographic Institution, Massachusetts) See also NBC's Breakfast TV show of November 10, 2008 with Alvin, Chris German and others.(Thanks for the tip, Chris.)
- Bridge, online resources for marine science education (Virginia Institute of Marine Science - College of William and Mary)
- Exploraquarium Frequently Asked Oceanography Questions(University of Washington, Seattle)
- Extreme 2000 - voyage to the deep(University of Delaware)
- ISIS(National Oceanography Centre, Southampton)
- JAMSTEC's ships, including the old Kaiko which went missing in 2003 and the Shinkais
- JAMSTEC's ROVs, including the new Kaiko, Kaiko 7000
- Kaiko(pdf file, at JApan Marine Science & TEchnology Center)
- Jason(Woods Hole Oceanographic Institution, Massachusetts)
- Ocean Planet - A Smithsonian Institution Traveling Exhibition
- Tour under the Pacific Ocean, based on real data. Submerge near Hawaii, move to Japan, and dive to the ocean's deepest point between Japan and New Guinea (NASA)
- Exploring the deep ocean floor: Hot springs and strange creatures(USGS)
- YOTO: 1998 - Year of the Ocean(NOAA)
A new
world depth record of 35,800 feet was set in 1960, when the bathyscaph Trieste descended to the bottom of the Mariana Trench. The bathyscaph was designed by scientist Auguste Piccard.
These web pages about the deepest location on earth - the Mariana Trench - contain some facts about the trench and links to related sites.
It started years ago with one large web page that was later split up into several pages to make downloading over a phone line easier. They are intended for people who are not very familiar with but interested in the Mariana Trench, plate tectonics and oceanography. They are for entertainment purposes only. Just for fun!
Btw, there is more on this site besides stuff about the Mariana Trench!