Monday, February 18, 2013

FTV 2/18/2013 Passing from the Caribbean Sea to the Atlantic

We knew we where on the last leg of our trip when we passed through the Windward Passage which is a strait in the Caribbean Sea, between the islands of Cuba and Haiti. The strait specifically lies between the easternmost region of Cuba and the northwest of Haiti. At 80 km wide, the Windward Passage has a depth of 1,700 m. Navassa Island lies on its southern approach.This passage connects the Atlantic Ocean to the Caribbean Sea, and is in the direct path of shipping between the Panama Canal and the eastern seaboard of the United States. From either the eastern tip of the Guantánamo Province of Cuba, or the western tip of Haiti's Nord-Ouest Department, it is possible to see lights on the other side of the Windward Passage.

Now we are back in the Atlantic heading for Buzzards Bay and our arrival to Taylor's point on Sunday, February 24.  With all our port visits behind us we’ll be collecting S2 wrist bands for storage until next year. Then we’ll have an examination day on Friday, and a day long cleaning day on Saturday that we call Field Day

For centuries, people have been challenged by the mysteries that lie beneath the blue depths of our ocean planet. Very little was known about the ocean until late in the nineteenth century, although nearly three-quarters of the planet is covered by ocean or seawater. Myths and misconceptions abounded. We used to think that the ocean depths were devoid of life. We thought that the seafloor was flat and that it was the same age as the continents. How different a picture we now have of the ocean as the sea has begun to yield its secrets.

As we sail through the Atlantic one can't help but ponder what lies beneath the deep blue water. In the 1870s, the HMS Challenger left England and sailed the world's oceans, throwing out weighted lines and taking soundings to measure the depths of the Atlantic, Pacific, Indian, and Arctic Oceans. For the first time, scientists had an inkling of the contours of the ocean floor, took samples of the plants and animals, and measured differences in water temperature and salinity. But the cold, dark water and extreme pressure of the depths kept scientists from knowing the secrets of the deep abyss.

Following in the footsteps of those pioneering oceanographers, today's scientists have overcome many of the challenges of the deep by using more sophisticated tools. They can send manned submersibles and sampling devices to plumb the ocean depths, taking photographs and samples of animal life and sediment to bring back to the surface for further study. Even space technology enters the picture. Satellite photos taken of the ocean provide a wide range of information, including water temperature and depth, seafloor topography, and the plankton populations. Using sonar and satellite data, scientists have been able to generate a new map of the ocean floor, thirty times more accurate than the best previous map. This map shows the ruggedness of the Mid-Ocean Ridge as it bisects the Atlantic Ocean. 

Scientists collect all of this data to understand how the ocean basin was formed and continues to evolve. Molten magma from Earth's interior spews out at the mid-ocean ridges, spilling over to either side and hardening to rocky basalt. As the crust pushes away from the ridges, it cools and thins, forming new seafloor and thus "widening" the ocean here. As this portion of the ocean floor widens, a section of the seafloor elsewhere is slowly sliding beneath the crust, becoming part of Earth's magma once again. Plate tectonics, the theory of Earth's crustal plates, thus helps explain ocean formation.
ROV  View
Satellite Image
Sonar Image
The development of new technologies for underwater exploration has led to exciting and lucrative expeditions. Photographs of the doomed Titanic taken by remote cameras from a submersible craft as it probed deep in the North Atlantic captured the imagination of the world. Today's scientists using sonar and other sensors to locate sunken submarines carrying gold. But whether in pursuit of knowledge or profit, all of these activities contribute to our understanding of the ocean.

These activities will show you how we map the ocean floor.
Explore the ocean floor
Mid Ocean Ridge activity
Use ships logs to map the ocean floor
Try this interactive

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