The Understanding the Atom Series

Nuclear energy is playing a vital role in the life of every man, woman, and child in the United States today. In the years ahead it will affect increasingly all the peoples of the earth. It is essential that all Americans gain an understanding of this vital force if they are to discharge thoughtfully their responsibilities as citizens and if they are to realize fully the myriad benefits that nuclear energy offers them.

The United States Atomic Energy Commission provides this booklet to help you achieve such understanding.

Edward J. Brunenkant, Director
Division of Technical Information

The ATOM and the OCEAN

by E. W. Seabrook Hull

CONTENTS

SEEKING ANSWERS 1

Energy for Exploration 3

THE WORLD OCEAN 6

Ocean Movements 7

A Mix of Elements 10

The Sea’s Interfaces 11

The Sea’s Resources 11

NUCLEAR ENERGY’S ROLE 13

Radionuclides in the Sea 13

Research Projects 23

Oceanographic Instruments 35

Environmental Safety Studies 41

The Atom at Work in the Sea 42

Ocean Engineering 51

Fresh Water from Seawater 52

Radiation Preservation of Seafood 54

Project Plowshare 56

A New Fram 56

THE THREE-DIMENSIONAL OCEAN 57

SUGGESTED REFERENCES 58

United States Atomic Energy Commission
Division of Technical Information
Library of Congress Catalog Card Number: 67-62476
1968

The ATOM and the OCEAN

By E. W. SEABROOK HULL

SEEKING ANSWERS

Historians of the future will record that man almost simultaneously unlocked the secret of atomic energy and ventured into new domains beneath the closed doors of the world ocean, in one of the greatest exploration endeavors of all time.

History may also show how these two efforts to benefit mankind became closely interthreaded—how nuclear energy, in its many forms and applications, played a major role in the efforts to explore and exploit “the other three-quarters” of our planet, and moreover, how the very development of a nuclear technology enforced our need to know more about the sea around us.

Nuclear energy is a fundamental physical phenomenon, like the actions of the wheel, the lever, or the inclined plane. Like chemical combustion or electricity, it is but another means for men to do useful work, whether that work be in the interests of science, commerce, recreation, or war. To this extent, nuclear energy is universal, as applicable in the sea as it is on land or in outer space. Wherever man goes and whatever he does, he requires energy to get him there and energy for his work or play when he arrives. Some of the places he now seeks to pioneer are hard to investigate by anyone encumbered with bulky traditional energy sources—coal, fuel oil, or storage batteries. The ocean in its full three-dimensional scope is one of these places.

The atom is the most concentrated source of energy, and one of the most diverse. Thus, not only are we able to do familiar things better with nuclear energy (the nuclear-powered submarine is a dramatic example), but we are also able to do things never before possible (such as studying the diffusion of dissolved salts in the open ocean or extending the useful life of seafoods through irradiation).

Nuclear energy has at last enabled us to realize the predictions of Jules Verne’s adventure tale, Twenty Thousand Leagues Under the Sea, and to build a true submarine—a craft whose submerged existence is limited only by the physiological and psychological endurance of its human crew. This fact in itself has added greatly to our need to learn much more about the ocean, for the sea is an opaque and strange environment in which the deadly game of hunt-and-be-hunted will be won by whoever knows the ocean best.

The very fact that we have nuclear energy means we have nuclear wastes; many of these inevitably find their way into the ocean, as all things do. We need to know more about the watery world before we can safely allow this inflow to continue.

In the waters of the seven seas are enough deuterium and tritium to power tomorrow’s thermonuclear power plants[1] for millions of years. These rare, heavy varieties of hydrogen, enormously abundant in the vastness of the sea, comprise an energy source without limit for all nations, which need only develop the technological ability to extract them and put them to work.

Energy for Exploration

For this exploration, men need to put instruments, navigation beacons (see figures on pages 46 and 47), and other devices on the deep ocean floor, where they must operate for long periods of time unattended and with no external source of power. Radioisotope-powered generators, capitalizing on the energy of disintegrating radioactive atoms, are almost the only devices capable of fulfilling these requirements.[2] Man also wants to do productive work under the ocean, such as drilling seafloor oil wells, mining, and salvaging for profit some of the tens of thousands of cargoes lost at sea during thousands of years of ocean commerce. Eventually, he even wants to farm the ocean floor.

All these activities require energy—energy in an environment where most sources cannot be applied. Above all, man wants to go down himself to explore, to work, and perhaps to direct nuclear-powered robots to do even more work. This means that small, manned, nonmilitary submersibles will be needed—vessels whose endurance should not be limited by the short life of traditional power sources, but should draw on the fissioning atomic nucleus, harnessed in small reactors.[3]

To work effectively in any environment, we must first know and understand it. This is the job of science. In the quest for knowledge and understanding of the ocean, nuclear energy provides scientists with better instruments to put down into the depths and wholly new techniques for the direct study of the many oceanic processes.

For example, take the role of radioisotope tracers: For the first time, these telltale atoms permit us to study the metabolism of tiny plankters, the often microscopic drifting creatures of the sea that in their incredible abundance form the base of the entire marine food chain, including fish eaten by humans. Even fallout isotopes from nuclear tests enable us to trace important physical oceanographic events, such as the ponderous process known as overturning, which transports oxygen-rich surface water to the deeps and nutrient-rich bottom water to the surface. Radioisotope tracers also provide a tool for studying the mechanics of littoral transport, which continually tears down some beaches and builds up others. They also enable us to determine if oceanic processes are likely to concentrate fallout particles and deliver them in dangerous doses through the food chain to our dinner tables.[4]

By using other nuclear energy technology, we are better able to ascertain the age and composition of deep ocean sediments and the rate at which they are deposited, how a tsunami (tidal wave) propagates across vast distances, how tides operate in the open ocean, where the brown shrimp of the Carolina coast go every fall, and the migration patterns of tuna, swordfish, and other valuable food fish.

These are just a few of the answers we seek from the world ocean—answers important for more productive fisheries, more accurate long-range weather forecasting, possible control of hurricanes and typhoons, pollution control, safer and more economical shipping, better recreation, and numerous other matters that bear on our health, well-being, and day-to-day lives.

On all these endeavors the ocean exerts a major influence. And in each, atomic energy is helping assemble and interpret answers.

THE WORLD OCEAN

But what of this environment into which, armed with the atom, we plunge with such enthusiasm and expectations? A portrait is in order, which must be brief, for not all the books ever written about the sea have yet described it fully.

The world ocean covers 70.8% of our planet. It contains 324,000,000 cubic miles of seawater. Living in it are upwards of a million different species of plants and animals. They range from one-celled organisms that can only be seen with a microscope to the largest creature ever to have lived on this earth—the giant blue (or sulfur-bottom) whale, captured specimens of which have exceeded 90 feet in length and 100 tons in weight.

The ocean’s depth ranges from 600 feet or less above continental shelves to more than 35,000 feet at the Marianas Trench. The mean depth is 12,451 feet. Sea bottom topography includes wide plains, the world’s longest mountain range, steeply rising individual truncated peaks called guyots (pronounced gee-ohs), gentle slopes, narrow canyons, and precipitous escarpments. Mountains higher than Everest rise from the ocean floor and never pierce the surface.

Ocean Movements

The ocean is constantly in motion—not just in the waves and tides that characterize its surface but in great currents that swirl between continents, moving (among other things) great quantities of heat from one part of the world to another. Beneath these surface currents are others, deeply hidden, that flow as often as not in an entirely different direction from the surface course.

These enormous “rivers”—quite unconstant, sometimes shifting, often branching and eddying in a manner that defies explanation and prediction—occasionally create disastrous results. One example is El Niño, the periodic catastrophe that plagues the west coast of South America. This coast normally is caressed by the cold, rich Humboldt Current. Usually the Humboldt hugs the shore and extends 200 to 300 miles out to sea. It is rich in life. It fosters the largest commercial fishery in the world and is the home of one of the mightiest game fish on record, the black marlin. The droppings of marine birds that feed from its waters are responsible for the fertilizer (guano) exports that undergird the Chilean, Peruvian, and Ecuadorian economies.

Every few years, however, the Humboldt disappears. It moves out from shore or simply sinks, and a flow of warm, exhausted surface water known as El Niño takes its place. Simultaneously, torrential rains assault the coast. Fishes and birds die by the millions. Commercial fisheries are closed. The beaches reek with death. El Niño is a stark demonstration of man’s dependence on the sea and why he must learn more about it.

There are other motions in the restless sea. The water masses are constantly “turning over” in a cycle that may take hundreds of years, yet is essential to bring oxygen down to the creatures of the deeps, and nutrients (fertilizers) up from the sea floor to the surface. Here the floating phytoplankton (the plants of the sea) build through photosynthesis the organic material that will start the nutrient cycle all over again. Enormous tonnages of these tiny sea plants, rather than being rooted in the soil, are separated from solid earth by up to several vertical miles of saltwater. Sometimes, too, there is a more rapid surge of deep water to the surface, a process known as upwelling.

Internal waves, far below the surface, develop between water masses that have different densities and between which there is relative motion. These waves are much like the wind-driven waves on the surface, though much bigger: Internal waves may have heights of 300 feet or more and be 6 miles or more in length!

Among other motions of the sea there are landslides, or turbidity currents, which are great boiling mixes of mud, rock, sand, and water rushing down submarine mountainsides at speeds of a mile a minute. They destroy everything in their paths and spread clouds of debris over the abyssal plains like a sandstorm, producing fanlike deposits radiating far out from the base of the slope. And there are tsunamis, or seismic sea waves—popularly misnamed “tidal waves”—that transmit energy from undersea earthquakes or volcanic eruptions. At sea, these waves are only a few inches high, but they may travel great distances at 500 miles an hour. As they approach the shoaling waters of a coast, they are slowed to about 30 miles an hour and build up great surface waves capable of destroying harbor and coastal installations.

A Mix of Elements

The sea is a chemistry, too. Over 60 elements have been discovered in measurable amounts in solution or in suspension in the ocean. Many of these are in the form of salts, making seawater a highly efficient electrolyte, and a most corrosive fluid. The study of corrosion and techniques for combatting it is a continuous one in which nuclear energy already has a principal role.

Because the sea is so much a chemistry, it is a potential source of minerals for the world’s growing industrial appetite. All of our magnesium and most of our bromine already are extracted directly from seawater. Oil and sulfur are mined from the sea floor or beneath it, as are coal (United Kingdom and Japan), iron ore (Japan), tin (Thailand and United Kingdom), diamonds (Southwest Africa), and gold (Alaska). In the layered sediments that cover the ocean-basin floors to depths of thousands of feet, geologists believe there also may be found some missing chapters of earth history.

The ocean, by and large, is an opaque fluid through which light travels only a few hundred feet and most other radiant energy not much more than a few yards; yet through this same fluid, sound waves, by contrast, have been transmitted and received over distances of many thousand miles.

The Sea’s Interfaces

What of the interfaces of the sea? Above three-quarters of the globe, water and air are in constant contact, continually exchanging heat and moisture. This is a major factor in the making of weather and climate. The sea constantly feeds electricity into the atmosphere, primarily through the electron-scrubbing action of tiny popping bubbles at the sea surface. It also lifts tiny crystals of salt and the remains of microscopic sea creatures into the air. Perhaps these are the nuclei on which moisture condenses to trigger hurricanes, since it is the latent heat of vaporization of air, made over-moist by long travel over the tropical sea, that provides a hurricane’s energy.

Along its land edges, the sea is constantly working on the shore—sometimes gently, sometimes violently—breaking down rock cliffs, opening bays and harbors, closing channels and inlets, smashing breakwaters and seawalls, and moving sand up and down and to and from beaches.

The Sea’s Resources

In summary, then, the ocean, the largest single geographical feature of our planet, is infinitely varied and infinitely complex. We are learning it bears on our day-to-day living in ways we never suspected. It is the largest resource of food for our exploding population, the largest resource of minerals with which to support the world’s burgeoning industries, the largest resource of energy, and, of course, it is the largest supply of water. It is mankind’s largest dumping ground for the wastes of cities and industries. It is the source of much pleasure and recreation.

Men already have lived experimentally for weeks at a time on the bottom of the ocean. Both sea floor laboratories and military bases are being planned or, in a few cases, installed. Sea floor mining complexes are in the conceptual design stage. It is only a matter of time before recreational “aquotels” are built safely below the sea’s restless surface. Private sports submarines are an actual, though costly, reality. It is not inconceivable that in the not-too-distant future human beings may overflow the land into complete, self-sufficient communities below the oceans.

NUCLEAR ENERGY’S ROLE

The role of nuclear energy in the study, exploration, and utilization of the world ocean is best defined by citing the specific oceanographic interests of the U. S. Atomic Energy Commission (AEC): Development of better instruments and devices for work and study in the ocean, development of ever-stronger national sea power, conversion of seawater to fresh water, possible modification of ocean boundaries, purely scientific studies to advance knowledge, and, indirectly at least, improving the state of oceanographic engineering. Among the technological products of the nuclear age are radionuclides, neutron sources and other radiation sources, radioisotope heat and electric generators, and nuclear reactors. All these are applied to ocean-related endeavors.

Several divisions of the AEC have important oceanic interests. These range from pure oceanographic research to development of specific instruments, nuclear reactors, radioisotopic power sources, and other devices for use in or under the ocean. The AEC also conducts extensive marine environmental studies to monitor the effects or ensure the safety of specific projects involving nuclear energy. A statistical summary of specific AEC programs in oceanography is shown in Table I on page 14.

Radionuclides in the Sea

Before we can follow the atom down into the sea, we must understand something about the potentials, both good and bad, of this incursion of one of our most advanced technologies into one of earth’s least understood environments. This adventurous probing has ramifications for studying both man-produced radioactivity in the sea and the ocean itself as an uncontaminated environment.

Radionuclides (radioactive atoms) can find their way into the sea from natural radiation sources or from nuclear energy operations undertaken by the United States and other countries since 1945. Specific man-made sources in the past may have included nuclear weapons tested in the atmosphere and under water, the cooling water and wastes of nuclear reactors, laboratories and nuclear-powered ships, containers of radioactive waste disposed of at sea[5], radioisotope energy devices, and intentional injection of radioisotope tracers for scientific research. In the future, they may also include reentry from space of upper-stage nuclear rockets or satellite-borne nuclear energy sources.

In order to evaluate the effects of these materials in the ocean environment, it is necessary to know many things. Just how much radiation is introduced? In what form? Where geographically? How are these radionuclides dispersed or concentrated physically, chemically, biologically, and geologically? What is the net result in each case now, and what will it be many years hence?

These questions are not answered easily. There is, as yet, no satisfactory laboratory substitute for the open ocean. Research for the most part must be conducted at sea, where tests and measurements are difficult at best, and where results therefore are often suspect. Further, if we are to study the effects of man-induced changes in a natural environment, it would have been advantageous to have known the nature of that environment before the changes were introduced—which, by and large, in the case of the ocean we do not. So we must start with a contaminated environment and try to separate what we have put there ourselves from what would have been there anyway. It isn’t an easy task to make the physical and biological observations that will make this distinction.

Adapted from The Mineral Resources of the Sea, by John L. Mero, American Elsevier Publishing Company, New York, 1964.

Many sea creatures are efficient, selective concentrators of “trace elements”, which occur in seawater only in minute portions. These elements are difficult enough to detect qualitatively and all but impossible to analyze quantitatively. Yet among the elements the sea’s plants and animals concentrate are the very materials with which we are apt to be most concerned: Strontium, cesium, cerium, ruthenium, cobalt, iodine, phosphorus, zinc, manganese, iron, chromium, and others. Radioisotopes[6] of all these elements occur as by-products of human nuclear activities. Many concentrating organisms are microscopic in size and are frequently impossible to raise in captivity. It is apparent that we are faced with a research program of considerable challenge and proportion.

We need to know how each marine species concentrates. Is it from the food it eats, by absorption from the water, or both? Does it concentrate an element by continuous accumulation, or is there a constant turnover of the material in the organism’s system? (In the first case, once the creature became radioactive it would remain so throughout its life or until the radioactivity decayed. In the second case, however, the radioactivity might be a transient condition, assuming the creature could find its way into uncontaminated water and were able to flush itself.) Obviously, both the cycling time of the radioisotope in the organism and its radioactive half-life[7] must be taken into account.

Even if we should manage to identify all the marine concentrators and gain some insight into their metabolic processes, this would be only a first step. For example, one tiny form of planktonic protozoan, acantharia, concentrates up to 15% of its own weight of strontium, including the radioisotope strontium-90. It is eaten by larger zooplankton (animals), such as copepods, which are eaten by little fish, which, in turn, are eaten by bigger fish, etc. Somewhere along this food chain, perhaps, a fish will come along that is favored for human dinner tables. How much strontium-90 has that fish accumulated through swallowing its prey and by absorption from the water? Is the radioactivity in its scales, bones, viscera, and other usually uneaten portions, or in its flesh?

It is probable, though as yet by no means proven, that among the million or so oceanic species of plant and animal life, there are concentrators of virtually all the 60 or more elements found in seawater. To identify and study them is an enormous undertaking, which is often possible only by using radioisotopes as tools.

And what of the immediate and genetic effects of radiation on each species? Studies of reef fish in the nuclear testing area in the Marshall Islands have shown that radioiodine in the water caused thyroid gland damage long after the amount of radioiodine remaining in the water was too low to be detected. Studies of salmon in the Columbia River have shown some physiological variations between those fish whose eggs and young were reared in radioactive waters and those that were not, though these variations have not been determined to be statistically significant or different from variations caused by other contaminants.

Studies are being made of the reproductive efficiency and patterns of sea creatures in a radiation-contaminated environment, compared with those in an uncontaminated environment, to learn such things as the numbers, survival rates, and sex ratios of the offspring, and any genetic abnormalities or mutations. Many more studies are needed. Always, the task is made difficult by insufficient detailed knowledge of the original natural environment, the limitations of laboratory experiments, and the mechanics of trying to follow the reproductive cycles of free-floating or swimming organisms in any statistically meaningful manner through successive generations.

One obviously important kind of research deals with the rate, pattern, and means by which radionuclides are distributed into the sea from a point source, such as the mouth of a river or a nuclear test site. Transport and diffusion of radioactivity can be, and are, influenced by physical, chemical, biological, or geological means, separately or all at once. This has led the AEC to support scientific studies of currents, upwelling, downwelling, convergence, diffusion, mixing rates, air-sea interactions, chemical and geological processes in the sea, and the horizontal and vertical migrations of sea life.

In much of the ocean there is an acoustic “floor”, known as the deep scattering layer (because of what it does to sound waves), which is believed to consist primarily of zooplankton. Every 24 hours the layer migrates up and down through several hundred feet of water. At night the countless small animals graze in the rich sea-plant pastures near the surface; during daylight, back at the lower level, they undoubtedly are heavily fed upon by larger animals. Over a period of time, the layer accounts for considerable vertical transport of materials. (See figure above.) Other life forms may move materials still farther down, or, in some instances, back up—as when the sperm whale descends to the depths to fight and best a giant squid, and then returns to the surface to eat it.

Constantly drifting downward is a great volume of material—the dead bodies, skeletons, excrement, and other waste from sea life at all depths. As it sinks there is a constant exchange of matter between it and the surrounding water through chemical, physical, and biological processes. Eventually, the molecules of material added to the bottom sediments may be returned to the water mass by bacteriological action or the eating and living habits of sea floor animals.

Biological transport works in other ways, too. Most pelagic (free-swimming) fish are great travelers. They account for a tremendous movement of material, namely themselves, from one place to another. Tuna, swordfish, whales, porpoises, and sea birds may travel thousands of miles in a single year. Such migrations may serve, variously, as mechanisms for either dispersal or concentration of elements or nutrients. The anadromous (river-ascending) fishes, such as salmon, herring, sturgeon, and shad, concentrate in freshwater streams in untold numbers to spawn. After hatching, the young seek the ocean and scatter widely until they, too, feel the urge to return to the rivers and lakes whence they came, to spawn and die there as did their ancestors.

Ocean currents may transport concentrations of radionuclides essentially undiluted for thousands of miles. Surface currents move at speeds of up to five knots (nautical miles per hour). Normally current waters do not mix readily with the water mass through which they pass. Because of the slowness of vertical circulation in the ocean, radionuclides deposited on the surface of the ocean may take a thousand years to reach the bottom. But the vertical transport sometimes is much more rapid: When the wind piles too much water against a coastline, the resultant downwelling (sinking) may move radionuclides suddenly into the deeper ocean. Or, conversely, when the wind and the rotation of the earth combine to force the surface water away from the coast, deep water may suddenly rise to replace it, a process known as upwelling.