A century and a half ago, biologists got a shock when technicians raised a section of telegraph cable from the bottom of the Mediterranean Sea. The cable had been resting at a depth of more than a mile, where scientists expected to find little or no life. Yet the cable was covered with life: corals, mollusks, worms, and a host of other organisms.
Examples of Ocean Cables. Credit: Atlantic-Cable.com website www.ftldesign.comTelegraph cables were responsible for many discoveries about the ocean floor -- from its depth and contours to how it changes.
By the 1850s, the telegraph was providing high-speed communication across countries and continents. And some smart businessmen realized that it could cut the communication time between continents from days or weeks to just minutes. So they launched big, expensive projects to lay cables across the oceans.
But even the Atlantic, which carried a lot of shipping traffic, was more poorly mapped than the surface of the Moon. There were few readings of ocean depths and temperatures, and few samples from the bottom.
So the cable companies sent expeditions to study the Atlantic. Scientists developed new techniques for measuring depth, and used them to discover that a tall “ridge” runs down the middle of the Atlantic.
After the cables were completed, they continued to provide new discoveries. In 1929, for example, an earthquake broke a dozen different cables. From the timing of the breaks, scientists were able to measure the motions of water and sediment along the bottom -- a rare message from the ocean depths.
