The lowdown on deep-sea mining
Long ago, the dark and chilly regions of the deep-sea floor were thought to be a biological wasteland. How could life survive, let alone flourish, in a region devoid of sunlight and therefore of plant life, subject to immense cold and the pressure of seawater at unimaginable depths? Even after the notion of a lifeless seafloor was dispelled by a burst of exploration in the mid-nineteenth century, in which dredges and nets brought up exotic new species of sea stars and sea urchins and living fossils such as the sea lily, a fundamental presumption persisted that the heights of biological diversity belonged to terra firma.
Darwin had posited that new species generally sprang up when habitat was disturbed-because natural selection favors change and adaptation in new circumstances – and when natural barriers such as mountains or deserts precluded interbreeding by the changing populations. With such prerequisites rare in the sea’s depths, the reasoning went, the terrestrial realm was undoubtedly far richer than the oceans that cover nearly 71 percent of the planet’s surface. Of the 1.4 million-some living creatures so far named by scientists, the number of known marine species stood, until recently, at about 160,000, with projected estimates of yet-undiscovered sea varieties bringing the total to about 200,000.
But in the past decade, new discoveries in our least-explored earthly environment have begun to alter that equation drastically. Life, it turns out, thrives in the dark and cold of ocean depths that can plunge, at their most profound, nearly seven miles. Scientists now believe that there may be 10 million – and perhaps as many as 100 million – previously unknown species of little animals residing in the sediments and waters of the deep. Even the lower estimates would equal the total suspected number of land-based species. Not the insects of the rainforest, but snails, worms, sea anemones, and their kin may well boast the greatest richness of species on the planet.
“This is changing our whole view about biodiversity,” says Dr. P. John D. Lambshead, a marine biologist at London’s Natural History Museum. “The quantity (of life we’ve found [on the ocean floor] is incredible. All sorts of ecologic theories that looked good based on terrestrial models, suddenly fall apart. We’re having to change all our ideas. Some believe that these creatures – often smaller than a headache pill and rarely longer than a cucumber – may play a vital part in maintaining the ecological balance of the planet.
Their unveiling, however, has been accompanied by a parallel development whose consequences are certain to be hotly debated in the decades ahead: the quiet revival of international interest in mining the deep-sea floor.
illustration of a seafloor chimney
Across broad expanses of the Pacific Ocean (and parts of the Atlantic), at depths of 5,000 meters and more, vast concentrations of nodules of valuable metals are known to exist. First discovered more than a hundred years ago during the Challenger expedition of the 1870s, the nodules are formed in a still-mysterious process, which is extremely slow and seems to be driven by microbes. A walnut-sized lump of manganese may be in excess of 10,000 years old. Despite a bout of gold rush fever in the 1970s, when a number of large mining concerns invested in exploration and in developing equipment for scooping the nodules off the seabed, the formidable economics of getting these rich lumps of rock up to the surface have so far prevented an all-out corporate assault. But they are known to blanket the sea floor for thousands of square miles in the eastern Pacific, containing not only manganese but sizable deposits of iron, copper, nickel, and cobalt.
And then there are the rock chimneys and vents of the mid-ocean volcanic ridges. The spectacular chimneys, monoliths of the deep as high as fifteen stories, are formed by seawater that has seeped down through fractures in the sea floor and become superheated by the volcanic temperatures below, so that it leaches minerals from the surrounding rocks. When the superhot water escapes back out to the open ocean, at temperatures that often exceed 500 degrees Fahrenheit and can easily exceed 600, it is instantly chilled and its mineral burden recrystallizes, forming a collar of rock. The chimney grows in a continuing process of percolation and crystallization, in which the hot water must travel ever higher before it can emerge and new minerals are laid down atop those just deposited. Old chimneys have died and new ones formed over thousands of years, and some contain large mineral deposits of zinc, copper, even silver and gold.
As with the mineral nodules, a short-lived gold-rush enthusiasm flared up in recent years over mineral deposits in the chimneys. In 1981, National Oceanic and Atmospheric Administration scientists discovered chimneys near the Galapagos Islands whose copper value alone (without taking mining and processing costs into account) was calculated at $2 billion. When the Reagan Administration learned that the Gorda ridge not far from the California and Oregon coast likely contained parallel mineral wealth, early in 1983 the president asserted U.S. sovereignty over all waters that extended 200 nautical miles from our territories and possessions. Eventually, substantial gold deposits were found on the Juan de Fuca ridge just beyond American territorial waters off Oregon. At the time, however, industry responded to the administration’s fervor with caution; the technological and economic barriers to deep-sea mining again prevented immediate development.
But the interest never really disappeared, and in this decade, it is beginning to see a resurgence. The United States and other industrialized nations have invested millions of dollars in developing suitable extraction technologies. Considerable experimental work has taken place over the past fifteen years, with consortia such as Ocean Management, Inc., developing tractor-like devices for scooping large quantities of minerals off the sea floor and hoisting them back to the surface for at-sea processing, after which the tailings would be dropped back into the ocean. The Japanese and Germans, whose land-based mineral holdings are limited, are especially interested in deep-sea resources. South Korea and China both have explorations under way in the Pacific. As for the United States, American claims in the Pacific zone cover about 190,000 square miles. And in some quarters, the level of boosterism remains high: Hawaiian Senator Daniel Akaka told a congressional hearing in 1993 that “the potential payoffs will be vast. The race is on.”
What is at stake environmentally can only be guessed at. Consider what we are just beginning to learn about the ocean’s living wealth. In 1967, when two marine biologists from the Woods Hole Oceanographic Institution set out to explore the ocean bottom about 100 miles off Cape Cod, a startling variety of fauna began to emerge. Howard Sanders and Robert Hessler, using newly devised sampling sleds that could catch and hold small creatures in fine-meshed nylon nets, brought up 365 different species in a single haul. Despite considerable scientific controversy over what the findings meant, scientists began to explore many new sites in the Atlantic and Pacific.
Then, in 1987, Dr. Fred Grassle, currently Director of the Institute of Marine and Coastal Studies at Rutgers University, came to the even more astounding conclusion that deep-sea life has as much genetic diversity as a tropical rainforest. Grassle used another technological advance called a box corer to make his captures. As described by the New York Times: “Like a giant square cookie cutter 20 inches on a side, it was dropped on a line from a ship and cut into a precise volume of muddy sea floor. A seal drawn across the corer’s bottom kept the sample from falling out during retrieval.” The density of life on the sea floor is relatively low – but the genetic diversity is so high that wherever a box corer touched down, new species were found in every square foot of mud. Grassle found nearly 1,600 different types among the nearly 275,000 invertebrates brought up to the surface.
Most of these new animals are still awaiting description by taxonomists, although such groups as polychaetes, sipunculids, and tanaids have been added to the classification lists. There are deep-ocean organisms that subsist only on ordinary terrestrial wood that somehow makes its way to the bottom. There is a worm whose spiral burrow is apparently designed specifically to encourage the growth of manganese-oxidizing bacteria, perhaps as a food source. And, as the science has advanced, Grassle’s conclusions have been supported and amplified by a number of other scientists. “When we did our intensive studies off the East Coast,” Grassle says, “the question was whether you’d find the same species when you go a long ways away. Some predicted that we would. But recent studies off Australia and California don’t find many species that are similar. The diversity regionally is very high, but so is the difference between regions.
“One of the puzzles,” Grassle continues, “is that all these things are in the mud and a lot of them eat mud. So how do these animals divide up the environment [into individual ecological niches]? It turns out that there are several different answers.”
illustration of brittle star, abyssal clam, deep-sea anamones, deep-sea sponge, deep-sea brachyuran crabs, and tube worms
First, the sediment-dwelling creatures leave behind numerous burrows and structures in the sediment that cannot be seen by observers or cameras in deep-sea craft, except sometimes with X-rays. Because there are no storms to erode the ocean bottom, the old burrows last a long time, providing many different kinds of shelters that different animals specialize in inhabiting. More important, however, is the fact that the organic detritus that serves as the food source of most of these animals-plankton, remains of corpses, dung, and other debris from above-tends to accumulate on the sea floor in patches, carried into old depressions or burrows by the slight bottom current. (The pattern is similar, Grassle notes, to what occurs in rainforests when a big tree falls, creating a source of nutrients for new seedlings.) And competition is minimal because the patches of food scattered across the seabed are very small, reducing the likelihood that two of the same species will reach any given patch. “Things can coexist,” explains Grassle, “where they otherwise wouldn’t if [the environment] were more homogenous.”
The rock chimneys and vents also shelter an astounding richness of previously unknown life. To the lasting surprise and excitement of biologists, the extremely hot, sulfur-ridden waters of the vents have been shown to support a plethora of microbes that thrive in conditions that would kill most bacteria instantly-including temperatures as hot as 700 degrees Fahrenheit. Some live in the boiling fluids, others inside creatures that surround the hot springs. Instead of sunlight, these microbes rely on heat and dissolved chemicals from the earth’s turbulent interior as their energy sources. They themselves become the base of the food chain for a host of fauna that colonize the chimneys: anemones, sponges, crabs, tube worms, fish, mussels, and other animals not yet recognized. So varied are the populations that every hydrothermal vent field examined to date has some species that are not found in any other vent field.
Just identifying all the new species being revealed could take years, to say nothing of the colossal difficulty of collecting the creatures and bringing them to the surface-let alone of studying them in situ as a functioning ecosystem. “If we’re only halfway right” about the extent of deep-ocean genetic diversity, suggests London scientist Dr. Lambshead, “many species could be forced into extinction before they’re even described.”
And so far, we lack even the most basic knowledge of what the consequences could be. As with extinction in the rainforests, extinction of deep-sea organisms could foreclose future opportunities to develop valuable medicines and technologies. Biotechnology companies are extremely interested in the sulfur-vent microbes, for instance, whose enzymes can be used at temperatures for which the enzymes of land-based microbes are useless. Indeed, because of their ability to process chemicals toxic to land based organisms, it is believed that some of these new enzymes might eventually provide ways to break down hazardous wastes.
Dr. Sylvia Earle, former chief scientist of the National Oceanic and Atmospheric Association and currently president of the Oakland, California-based Deep Ocean Exploration and Research and an NRDC trustee, harbors still more basic concerns. “We have so little understanding of the fundamental processes that drive our planetary systems,” Earle says. For instance, she asks, “how important are the microbes in the deep sea that yield [the metal-bearing] nodules? They may be far more valuable as part of a functioning system that we haven’t even begun to guess at” than as sources of minerals.
“The deep-sea ecosystem is so extensive in area,” adds Grassle, “that it certainly plays a significant but unmeasured role in the overall dynamics of ocean chemistry.”
Moreover, as William J. Broad wrote in his recent book, The Universe Below, “the ominous question … is not whether seabed mining will kill sea creatures but how great the carnage will be.” Scientists cannot yet even guess at the long-term implications of the destruction of animals in the dredging paths, the impact of plumes of sediment that would cloud the water and rain down on surrounding areas near and far, or the effects of possible releases of toxic chemicals. But there is reason to suspect that some of the effects would be severe. Earle points out that disturbing the metallic nodules, for example, “can release into the surrounding seawater chemicals or substances that have been stabilized over the ages. Some of these metals are toxic to many creatures, but favored by others that prosper in the presence of the compounds. Their extraction could have a widespread down stream impact.”
Furthermore, as Elliot Norse, founder of the Marine Conservation Biology Institute in Seattle, explained in a 1993 book, “in the cold, lightless abyssal realm that predominates even in the tropics, life processes for many species appear to be very slow, and life spans are long. For example, it has been estimated that it takes the abyssal clam Tindaria callistiformis 100 years to reach the length of 8.4 millimeters (0.33 inches)…. Slow growth rates and the sluggish reproduction that accompanies this might make deepsea ecosystems especially slow to recover even after stresses have been removed.”
And if the globe’s most undisturbed and stable environment is strip-mined, adds Norse, scientists may never even have the chance to evaluate the effects: “Unfortunately, most of the mining will happen in international waters where no nation has jurisdiction, far from sight. Only the people making millions from selling the minerals will be out there, so we won’t know nearly as much as we need to know about the impact of this activity.”
illustration of a polychaete worm
Such questions make clear why a precautionary approach is crucial with the prospect of ocean mining. But while the political climate has long been unfavorable for the kind of rational, deliberate process that is needed for developing international environmental safeguards, recent developments hold out some hope.
In 1982, the United Nations finalized the treaty known as the Law of the Sea, a landmark international effort to establish guidelines for future use of the oceans. The treaty, which has been called “perhaps the most complex legal agreement ever achieved,” contains provisions on fishing, ocean pollution, the regulation of territorial waters and international straits, and many other issues. (It was the Law of the Sea, for instance, that allowed countries to claim sole natural resource management rights to the waters extending 200 miles from their coasts.) But the most controversial section has always been the provisions on mining. A great number of developing countries participated in framing the treaty, and the 1982 version not only proclaimed the deep-sea floor beyond the 200-mile zones to be “the common heritage of mankind,” but also required industrialized countries to share both their claims and their technology with less developed nations.
This stipulation did not sit well with American corporations or the Reagan Administration. The treaty’s mandate was “a sure way to kill interest in investing in ocean mining technology,” said an engineer with Lockheed’s Ocean Minerals Division at the time. Accordingly, the United States refused to endorse the final text; other developed nations followed suit. The Reagan Administration also encouraged U.S. companies to ignore the proposed treaty and mine the seas in accordance with U.S. law-although, as noted above, the economics of the task prevented immediate development.
Despite the U.S. opposition, the treaty went into force in 1994 after it was ratified by sixty nations. Today, some 110 nations have signed on, with the continuing exception of this one. But according to Tucker Scully, the State Department’s Director of the Office of Oceans, the Clinton Administration supports seeking congressional approval for America’s entry-now that a compromise has been worked out on the deep-sea mining section. “The economic and ideological provisions we felt were unacceptable, including mandatory transfer of technology, have been basically removed,” says Scully. “So has the top-heavy institutional structure for overseeing proposals to mine. The focus is now on market forces subject to strong environmental controls.”
The question is, exactly how strong will those controls be? The treaty established an International Seabed Authority that includes all the signatory parties and must, among other things, adopt rules for environmental protection. In addition, an executive committee has the power to approve work plans for mining and to issue emergency orders to prevent serious harm to the environment. As with any law, however, these provisions can only be as strong as their enforcement. The Authority is now in the process of drafting its mining code, including the environmental rules, but a complete draft is not expected until next year. Sylvia Earle and other marine scientists believe that one essential environmental provision would be to set aside very large areas-large enough to account for the uncertainty over how far a plume of sediment or toxics might extend-for exclusion from mining. But whether the code will include such a mandate is yet to be seen.
In 1987, the late James Broadus of the Woods Hole Oceanographic Institution published an economic study that concluded that, compared to onshore mining, deep-sea mining remained a “wasteful, losing venture.” Since then, says Andrew Solow, a Woods Hole associate scientist, “Nothing has happened to change that basic picture. There is no real shortage of any of these materials from terrestrial sources.” Porter Hoagland, another Woods Hole scientist, agrees: deep-sea mining, he says, probably will not become commercially feasible until well into the next century-if ever. Even the State Department’s Tucker Scully says that commercially viable opportunities simply do not yet exist.
But there are plenty of people who are eager to make it happen. Retired professor and oceanprospecting pioneer John Flipse insists that the costs of land-based mining and its environmental impact are escalating while the quality of the ores diminishes. Like many others, Flipse is convinced that “ocean mining is going to work. The feasibility has been demonstrated. Ultimately, it’s the sea or metal substitution.”
illustration of a tripod fish
And so the drive to mine the oceans continues. Every few months, it seems, some government or entrepreneur takes another step toward actually moving rock. Last spring, China announced that the first mission of the deep-sea robot it has developed will be to prospect for metallic nodules. In September, the International Seabed Authority approved work plans submitted by seven “pioneer investors” based in India, France, Japan, Russia, China, and elsewhere. Later that same month, the Cook Islands off New Zealand announced a memorandum of understanding with a Norwegian enterprise for dredging nodules of manganese and cobalt.
Will the ventures bear fruit, or fall by the wayside like those of the past? At this point, it is anybody’s guess. But in the meantime, scientists keep urging the world to go slow. Mining would be “like carving up North America-deciding where the cities, shopping centers, and protected areas should be-when you’ve never even seen the place,” says Sylvia Earle. “We may be on the verge of triggering events that will create a whole new set of circumstances for the deep sea.”