What do oceanographers and astronauts have in common? Observations of the complex interactions between different Earth systems, for one. Astronauts aboard the International Space Station routinely observe and photograph the Earth’s surface to visualize the complicated interfaces between the atmosphere, the ocean, the land, and life on the surface. Oceanographers are also interdisciplinary students of the Earth; their interests include geology, chemistry, hydrology, and biology. Currently, a team of scientists is cruising the eastern Pacific Ocean off the coast of Mexico and is preparing for submersible dives on the East Pacific Rise, part of the world’s mid-ocean ridge system.
Submerged in the Atlantic Ocean off the coast of Spain and Portugal are giant, salty whirlpools of warm water. These deep-water whirlpools are part of the ocean’s circulatory system, and they help drive the ocean currents that moderate Earth’s climate. Warm water ordinarily sits at the ocean’s surface, but the warm water flowing out of the Mediterranean Sea is so salty (and therefore dense) that when it enters the Atlantic Ocean at the Strait of Gibraltar, it sinks to depths of more than 1,000 meters (one-half mile) along the continental shelf. This underwater river then separates into clockwise-flowing eddies that may continue to spin westward for more than two years, often coalescing with other eddies to form giant, salty whirlpools that may stretch for hundreds of miles. Because the eddies originate from the Mediterranean Sea, scientists call them “Meddies.”
Acquired May 17, 2011, and May 22, 2011, these natural-color images show sediment in the Gulf of Mexico, one consequence of Mississippi River flooding.