Sunday, February 11, 2007
Thursday, February 8, 2007
The Geology of the Caribbean Sea
My project is on the Caribbean Sea, my section is on the Geology of the Caribbean Sea. I will give a summary of what i have so far.
Intro.: The Caribbean Sea is one of the largest salt water seas and has an area of about 2,754,000 km² (1,063,000 square miles). The Caribbean Sea is a tropical sea in the western hemisphere; it is a part of the Atlantic Ocean, bounded on the south by South America, on the west and south by Mexico and Central America, and on the north and east by the Antilles. Atlantic Ocean enters the Caribbean through the Anegada Passage lying between the Lesser Antilles and Virgin Islands and the Windward Passage located between Cuba and Haiti. The Greater Antilles islands of Cuba, Hispaniola, Jamaica, and Puerto Rico lie to the north, and a plethora of Lesser Antilles bound the sea on the east situated southeast of the Gulf of Mexico. It is a Mediterranean Sea that covers most of the Caribbean Plate. The entire area of the Caribbean Sea, the numerous islands of the West Indies, and adjacent coasts, are collectively known as the Caribbean. The sea's deepest point is the Cayman Trough, between Cuba and Jamaica, at 7,686 m (25,220 feet) below sea level. The Caribbean coastline has many gulfs and bays: the Gulf of Venezuela, Gulf of Darien, Golfo de los Mosquitos and Gulf of Honduras.
Geology: The Caribbean sea floor is divided into five basins that are seperated from each other by underwater mountain ranges and ridges. The sea's age has been estimated to be anywhere from 20,000 years to 570 million years. The Cayman Trough is where the deepest points in the sea lie, with depths reaching 7,686m or 25,220 feet (approximately), inspite of this the Caribbean Sea is considered relatively shallow compared to other bodies of water.
The Hispaniola and Puerto Rico trenches are the two oceanic trenches that are found on the Caribbean Sea floor, these put the area at a higher risk of earthquakes. These underwater earthquakes pose a threat of generating tsunamis that could have devastating effects on the Caribbean Islands. Scientific data reveals that over the last 500 years the area has seen a dozen earthquakes above 7.5 magnitude. Volcanic activity is also common in the Caribbean, as well as destructive hurricanes that originate over the sea or in the Atlantic.
Global Warming
While we are on the topic of global warming, i found this video also talking about it.
http://www.youtube.com/watch?v=ox0wOCT2fTg
http://www.youtube.com/watch?v=ox0wOCT2fTg
Methane alters ocean floor
The following study was taken from sciencedaily website, it looks at the effects of methane on the ocean floor. The study appears in the journal Geophysical Research Letters.
MOSS LANDING, Calif., Feb. 7 (UPI) -- U.S. geologists say methane gas bubbling through seafloor sediments has created hundreds of low hills on the floor of the Arctic Ocean.
Monterey Bay Aquarium Research Institute geologists Charlies Paull, William Usser and colleagues say the origin of the ocean floor hills has puzzled scientists since the features were discovered in the 1940s.
The team collected sediment and gas samples from the underwater hills they call "pingo-like" features on the Beaufort Sea Shelf, off the north coast of Canada.
Pingos, small, dome-shaped, ice-cored hills, are found in many Arctic regions. Previous studies suggested pingo-like features are pingos that formed on land, but were submerged when sea level rose following the last ice age.
Paull and colleagues propose an alternative hypothesis: Pingo-like features form when methane hydrate -- a frozen mixture of gas and seawater -- decomposes beneath the seafloor, releasing gas that squeezes deep sediments onto the seafloor, much as toothpaste from a tube.
Since methane is a potent greenhouse gas, scientists would like to know how much comes from the seafloor worldwide. Future research on methane hydrates and pingo-like features may help address that question. Taken from: http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-20070207-08032400-bc-us-oceanmethane.xml
MOSS LANDING, Calif., Feb. 7 (UPI) -- U.S. geologists say methane gas bubbling through seafloor sediments has created hundreds of low hills on the floor of the Arctic Ocean.
Monterey Bay Aquarium Research Institute geologists Charlies Paull, William Usser and colleagues say the origin of the ocean floor hills has puzzled scientists since the features were discovered in the 1940s.
The team collected sediment and gas samples from the underwater hills they call "pingo-like" features on the Beaufort Sea Shelf, off the north coast of Canada.
Pingos, small, dome-shaped, ice-cored hills, are found in many Arctic regions. Previous studies suggested pingo-like features are pingos that formed on land, but were submerged when sea level rose following the last ice age.
Paull and colleagues propose an alternative hypothesis: Pingo-like features form when methane hydrate -- a frozen mixture of gas and seawater -- decomposes beneath the seafloor, releasing gas that squeezes deep sediments onto the seafloor, much as toothpaste from a tube.
Since methane is a potent greenhouse gas, scientists would like to know how much comes from the seafloor worldwide. Future research on methane hydrates and pingo-like features may help address that question. Taken from: http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-20070207-08032400-bc-us-oceanmethane.xml
Monday, February 5, 2007
Why is the ocean salty?
The ocean is salty because of the gradual concentration of dissolved chemicals eroded from the Earth's crust and washed into the sea. Solid and gaseous ejections from volcanoes, suspended particles swept to the ocean from the land by onshore winds, and materials dissolved from sediments deposited on the ocean floor have also contributed. Salinity is increased by evaporation or by freezing of sea ice and it is decreased as a result of rainfall, runoff, or the melting of ice. The average salinity of sea water is 35 o/oo, but concentrations as high as 40 o/oo are observed in the Red Sea and the Persian Gulf. Salinities are much less than average in coastal waters, in the polar seas, and near the mouths of large rivers.
Sea water not only is much saltier than river water but it also differs in the proportion of the various salts. Sodium and chloride constitute 85 percent of the dissolved solids in sea water and account for the characteristic salty taste. Certain constituents in sea water, such as calcium, magnesium, bicarbonate, and silica, are partly taken out of solution by biological organisms, chemical precipitation, or physical-chemical reactions. In open water the chemical composition of sea water is nearly constant. Because of the stable ratios of the principal constituents to total salt content, the determination of one major constituent can be used to calculate sea water salinity. For minor constituents and dissolved gases the composition is variable and therefore ratios cannot be used to calculate salt Circulation and mixing, density and ocean currents, wind action, water temperature, solubility, and biochemical reactions are some of the factors that explain why the composition of water in the open sea is almost constant from place to place.
Taken from http://www.palomar.edu/oceanography/salty_ocean.htm
Sea water not only is much saltier than river water but it also differs in the proportion of the various salts. Sodium and chloride constitute 85 percent of the dissolved solids in sea water and account for the characteristic salty taste. Certain constituents in sea water, such as calcium, magnesium, bicarbonate, and silica, are partly taken out of solution by biological organisms, chemical precipitation, or physical-chemical reactions. In open water the chemical composition of sea water is nearly constant. Because of the stable ratios of the principal constituents to total salt content, the determination of one major constituent can be used to calculate sea water salinity. For minor constituents and dissolved gases the composition is variable and therefore ratios cannot be used to calculate salt Circulation and mixing, density and ocean currents, wind action, water temperature, solubility, and biochemical reactions are some of the factors that explain why the composition of water in the open sea is almost constant from place to place.
Taken from http://www.palomar.edu/oceanography/salty_ocean.htm
Saturday, February 3, 2007
The Ocean zones & a few other terms
A quick look at the Ocean Zones:
Scientists have divided the ocean into separate and distinct levels or zones, starting with the surface and going down to the very bottom in the following order...
Scientists have divided the ocean into separate and distinct levels or zones, starting with the surface and going down to the very bottom in the following order...
- Epipelagic: this is the top ocean layer, this is at or near the surface of the open ocean, here the water is warmer from sunlight and photosynthesis is most effective.
- Mesopelagic: mid- ocean; this is the layer of ocean water between 200m and 800m down. Here sunlight penetrates the water enough to be beneficial tot he species that live there.
- Bathypelagic: deep water; where penetration of sunlight is extremely low. The layer ranges from 800m to 4,000m deep.
- Benthopelagic: the layer of ocean that is just above the bottom; the sea floor, where the term benthic refers to the sea floor itself.
- Bathyal Zone: the benthopelagic areas of the ocean that are on continental slopes.
- Abyssal Zones: These are the benthopelagic areas of the ocean that are ont he sea floor plain.
Hadopelagic: This is the really DEEP water, down in the deepest ocean trenches.
Fathom: A fathom is a unit of length in Standard English that is used to measure ocean depths. It is approximately 6 vertical feet. To get the total depth in feet from fathoms given, just multiply by 6. For example, 500 fathoms = 500 x 6ft. = 3,000 feet.
League: A league is also a unit of length (or distance) that is used to measure ocean depths. It is not used in science, but in literature. One league = 3 miles (or 4.8 km).
Challenger Deep: Challenger deep got it's name from the British survey ship Challenger II, which pinpointed the deep water off the Marianas Islands in 1951. Then in 1960, the US Navy sent the Trieste (a submersible - a mini-submarine designed to go really deep) down into the depths of the Marianas trench to see just how far they would go, they touched bottom at 35,838 ft/10,923m. That means, while they were parked on the bottom in the bathyscaphe, there were almost seven miles/11km of water over their heads!
If you cut Mount Everest off at sea level and put it on the ocean bottom in the Challenger Deep, there would still be over a mile of water over the top of it! Read more at http://www.extremescience.com/DeepestFish.htm
Thursday, February 1, 2007
Vessel leaks 200 tonnes of fuel
There are pollution fears after oil leaked from the MSC NapoliSome 200 tonnes of oil have leaked from a fuel tank on the stricken cargo ship MSC Napoli, beached off the Devon coast, coastguards have confirmed.
The ship has also lost some 200 containers overboard, including two holding "dangerous but low-risk" goods.
The ship has also lost some 200 containers overboard, including two holding "dangerous but low-risk" goods.
A sheen of oil eight kilometres (five miles) long is now on the sea surface.
The ship suffered structural damage during Thursday's storms and was deliberately beached off Branscombe to stop it sinking in deep water.
It is sharply listing and there are fears it could capsize and break up at any time.
An operation to pump the remaining oil on board is due to begin on Monday morning. The remaining containers could also then be winched off.
The ship suffered structural damage during Thursday's storms and was deliberately beached off Branscombe to stop it sinking in deep water.
It is sharply listing and there are fears it could capsize and break up at any time.
An operation to pump the remaining oil on board is due to begin on Monday morning. The remaining containers could also then be winched off.
3,500 tonnes of oil- The 62,000 tonne vessel was carrying 2,323 containers, 158 of which are classed as having potentially hazardous contents.
Of the 200 that have gone overboard, one contained battery acid and perfumes, and one small gas bottles for car airbags.
Maritime and Coastguard Agency spokesman Paul Coley said these were "considered dangerous goods but for us they're low-risk."
Others housed a variety of goods including BMW motorbikes and car parts.
Not all of the containers have been found and some have broken up. Some may have sunk while others could be far out to sea.
The ship also contains a further 3,500 tonnes of heavy fuel oil in tanks, but coastguards believe these have not split.
They believe 200 tonnes is close to the maximum that will leak out of the ship's engine room.
'Sensitive' coastline
The ship was being towed to Portland Harbour in Dorset for a salvage operation, but on Friday coastguards decided to beach it because of its structural damage - a fracture on both sides.
An eight-person salvage team is on board, and a team of divers is being flown in to join them.
Environmental damage is so far said to be minimal. Three oil-covered birds have been found.
Residents in nearby Sidmouth have spoken of the concern about the leak.
One man told the BBC: "It's a real worry that we could get pollution and there's a lot of wildlife lives on these shores, and certain rare sea birds."
Julian Wardlaw, of the Environment Agency, said: "We have an extremely sensitive bit of coastline; we are dealing with a World Heritage Site and we are working to make sure that damage is minimised."
Of the 200 that have gone overboard, one contained battery acid and perfumes, and one small gas bottles for car airbags.
Maritime and Coastguard Agency spokesman Paul Coley said these were "considered dangerous goods but for us they're low-risk."
Others housed a variety of goods including BMW motorbikes and car parts.
Not all of the containers have been found and some have broken up. Some may have sunk while others could be far out to sea.
The ship also contains a further 3,500 tonnes of heavy fuel oil in tanks, but coastguards believe these have not split.
They believe 200 tonnes is close to the maximum that will leak out of the ship's engine room.
'Sensitive' coastline
The ship was being towed to Portland Harbour in Dorset for a salvage operation, but on Friday coastguards decided to beach it because of its structural damage - a fracture on both sides.
An eight-person salvage team is on board, and a team of divers is being flown in to join them.
Environmental damage is so far said to be minimal. Three oil-covered birds have been found.
Residents in nearby Sidmouth have spoken of the concern about the leak.
One man told the BBC: "It's a real worry that we could get pollution and there's a lot of wildlife lives on these shores, and certain rare sea birds."
Julian Wardlaw, of the Environment Agency, said: "We have an extremely sensitive bit of coastline; we are dealing with a World Heritage Site and we are working to make sure that damage is minimised."
Meanwhile, it has emerged that the ship previously ran aground off Singapore in 2001.
It was previously named CMA-CGM Normandie and ran aground in the Strait of Malacca in 2001.
The ship subsequently had to undergo "major repairs" in Vietnam, according to Tore Hoifodt, senior vice president at DNV, which classes and inspects cargo ships.
It was previously named CMA-CGM Normandie and ran aground in the Strait of Malacca in 2001.
The ship subsequently had to undergo "major repairs" in Vietnam, according to Tore Hoifodt, senior vice president at DNV, which classes and inspects cargo ships.
Pictures from accident and map showing general area:
Subscribe to:
Posts (Atom)
