Scientists use new vehicles to study ocean depths

"How do they make the ocean?'" asked Adrian Matias, 8, a second-grader at Diamond Lake School in Mundelein.

So much of the Earth is covered by water that you might think the Earth is one giant ocean dotted with a few continents.

That wasn't always the case. "Scientists have theories about the early formation of the Earth's ocean, but the details are not known because this happened a very long time ago -- over 4.5 billion years -- and scientists are still searching for and interpreting clues to this mystery," said Dr. John Farrington, scientist emeritus (and former Dean) at Woods Hold Oceanographic Institution in Woods Hole, Mass.

When the Earth was newly formed, water combined with other chemicals in rocks making up the early Earth. "The evidence suggests that the Earth heated, melting many of the chemicals in rocks. These chemicals separated forming the Earth's core, mantle and crust and then began cooling. During this process the beginnings of continents and ocean basins were formed," Farrington said.

Some gasses escaped from the rocks. Gravity trapped gasses and the atmosphere was formed. Like a covered pot of boiling water, the process created water vapor and other bases that condensed and became rain. Slowly, over thousands of years, the water filled the ocean basins.

At one time in this process, surface land joined as one giant continent called Pangea. On the ocean floor, massive chunks of the Earth's crust covered the core in uneven pieces called tectonic plates. The plates shifted along their borders, and when they moved apart -- very, very slowly -- molten magma from the inner layers of the Earth seeped out, creating new ridges, peaks, fissures, chasms. Over millions of years, this process helped to create ocean basins.

Plate movement caused the giant Pangea land mass to break up, and eventually it became seven continents. The plate sections continue to shift today, and that movement can sometimes result in earthquakes.

Ever since the ocean was formed, weathering and rain has dissolved rocks and minerals and the run off seeps into the ocean. Much of the runoff contains the chemicals that make up part of the "salt" of the ocean. Volcanoes under the sea and on land also have added gasses, rocks and minerals into the salt mix.

Dr. Farrington said there is a natural cycle of warming and cooling that has happened several times since the oceans were formed. "Today there is strong evidence about how human activities of burning fossil fuels and clearing land by burning have resulted in the release of gasses that cause increased warming in the atmosphere," Farrington said.

Scientists at the Woods Hole Oceanographic Institution, other ocean institutes and university departments worldwide have been studying the ocean's origins by examining rocks and magmatic forces deep below the ocean surface. Uncovering clues to the ocean's past sometimes involves using remote controlled robotic under water vehicles that are directed to dive as many as three miles under water to collect samples.

Find out more about the under water expeditions by reading the Woods Hole online magazine "Dive and Discover" at www.divediscover.whoi.edu.