With only about 5 percent of the sea floor explored in detail, a picture is emerging of a vast system of natural undersea dynamos, fueled by hot springs, that produce not only valuable mineral deposits, but habitats for unique, heat-loving organisms that can provide materials for products ranging from detergents to pharmaceuticals.
That is the view of marine geologist and geophysicist Peter A. Rona of the department of geological sciences and the Institute of Marine and Coastal Sciences at Rutgers, The State University of New Jersey. Rona, a sea-floor mineral resources consultant to the United Nations, has spent more than 40 years exploring the oceans. He published an overview of current work entitled “Resources of the Seafloor” in the international journal Science Jan. 31.
One of Rona’s discoveries is a metal-rich mound the size and shape of the Houston Astrodome two-and-a-half miles under the middle of the Atlantic Ocean. “At least 50,000 years in the making, the mound is composed largely of combinations of the metals copper, iron, zinc, gold and silver. It was produced by jets of hot, metal-rich sea water,” he said.
Rona, who continues to dive and has logged research expeditions aboard 11 of the world’s 13 deep-diving human-occupied submersible research vessels, said the oceans are no longer considered simply containers for minerals washed off the continents. “Before the discovery of plate tectonics the oceans were thought of as big bathtubs,” he said. “Now we know that the earth’s crust, most of it under the ocean, is cracked into plates that move and allow heat and materials from the earth’s interior to escape. As result we know that most of the minerals on the sea floor probably come from sources under the sea floor.”
In fact, Rona said, there is probably as much water circulating under the sea floor as there is in the oceans themselves. “Cold, dense sea water seeps for miles downward through the crust. When it reaches hot layers in the mantle, the water heats and rises with force, dissolving metals from surrounding rocks and blasting out of the sea floor at 650 degrees Fahrenheit. Often the jets are so dense with minerals we call them ‘black smokers.'”
When the hot jets reach the cold ocean water, the minerals condense and create structures on the sea floor, said Rona. “Besides mineral deposits, the hot water and minerals provide habitats and energy for heat-loving microbes at the bottom of a food chain of newly discovered deep-ocean life forms. These microbes contain enzymes and bioactive compounds that can be used in such applications as DNA finger-printing, detergents, food preservation, oil-drilling and pharmaceutical production.”
Rona recently delivered a keynote address at a commemoration of the 20th anniversary of the United Nations Convention on the Law of the Sea, which provides a “constitution” for management of the oceans. “When the Law of the Sea was negotiated, we had little realization of how far we had to go in terms of retrieving these materials commercially and no knowledge of the microbes or living systems present,” he said.
“Miles down, the ocean is an extremely hostile environment. Sea water is corrosive; the pressures are huge. It’s analogous to exploring outer space in terms of a hostile and alien environment,” he said. “We are only beginning to discover the immense richness and diversity of sea floor resources.”
The public will have an opportunity to view Rona’s undersea work in a giant-screen film to be released later this year, entitled “Volcanoes of the Deep Sea,” produced by the Stephen Low Company and Rutgers University. Major funding for the film project is provided by the National Science Foundation with additional outreach funding provided by the National Oceanic and Atmospheric Administration Office of Ocean Exploration.
