One of my five fellow aquanauts, marine biologist Mark Patterson, astutely observed that we were about 20,000 millimeters below the surface—some 60 feet—in a warm, dry suite of rooms, with access to the best swimming pool in the world: the ocean. A rectangular hole in the floor was the entrance to the lab and our exit to the sea beyond, with the pressure inside Aquarius keeping the water from rushing in. For as long as twelve hours a day (or night), scientists who work in Aquarius can explore that richly endowed Florida reef, observe and document the behavior of marine life, conduct experiments, enjoy the perspective of a resident, and make the most of the chance to occupy what is presently the world’s only “space station in the sea.”

  When Jules Verne was born, in 1828, there were about a billion people on Earth, and not one of them had a face mask, radio, television, car, or anything made of plastic, among many other aspects of life we now take for granted. The industrial revolution was well underway, with an explosion of new technologies, new agricultural methods, new means of transportation and communication that led to the greatest era of change in human history. From then to now, population has grown sevenfold, and sustained economic growth has advanced more than tenfold for individual income.

  When I was born, in the mid-1930s, Earth’s 2 billion people were entering an unprecedented era of prosperity, despite crippling wars and diseases that had taken the lives of millions. Penicillin was not available soon enough to save my brother Don from a fatal ear infection, but revolutionary changes were underway across all aspects of life, from medical care and food production to energy sources and what seemed to be magical new ways to instantly communicate with neighbors nearby as well as with people on the other side of the planet.

  As a child, living in a ferment of new discoveries, I thought nothing was beyond the power of human enterprise. With wires, tubes, and ingenuity, my father built our family’s first radio—a “crystal set” that brought distant voices and music to our New Jersey farm. We planted new kinds of hybrid corn that yielded far more than seeds collected from the previous year’s crop. Prosperity surged through the aftermath of the Great Depression and two world wars, doubling the population in the course of a half-century, reaching 4 billion by 1980. With nearly 7 billion of us today and 2 billion more expected by the middle of this century, our growth as a species appears boundless.

  But the benefits have come at a cost. About half of the world’s original forests have been consumed, most of them since 1950. Conversion of forests, deserts, marshes, grasslands, and other natural systems for agriculture, cities, and other human purposes has resulted in the loss of thousands—about 75 percent—of the native plants and animals that provide the genetic basis for all agricultural crops and domesticated farm animals. At the same time, a full 90 percent of all large wild fish (and many small kinds as well) have disappeared from the world’s oceans, the result of devastating industrial fishing. Entire ecosystems, with their treasury of distinctive plants and animals, have been extinguished, underwater as well as above. Only in times of great natural catastrophe—such as when comets or meteors have collided with our planet—has the way forward been so swiftly and dramatically altered. Never before have such dramatic changes been caused by the actions of a single species.

  My goal during the July Aquarius mission was to observe and document changes in a part of the world that I had first witnessed as a young scientist in 1953 and later explored during thousands of hours using the ingenious Self-Contained Underwater Breathing Apparatus—SCUBA—developed in the 1940s and marketed as the Aqua-Lung by the pioneering ocean explorer Jacques Cousteau and a colleague, engineer Émile Gagnan. I experienced my first underwater breath in Florida, and during trips to the Florida Keys, I marveled at the clarity of the ocean and the abundance and diversity of life. Pink conchs plowed trails though seagrass meadows, and schools of colorful fish crowded the branches of elkhorn and staghorn coral. Long, bristly antennae marked the presence of lobsters under ledges and in crevices, and elegantly striped and irrepressibly curious Nassau grouper followed me on most dives, and likely would have continued onto the beach but for the limitations of fins and gills.

  Six decades later, I note the difference. The water along the Florida Keys is often gray and murky. The great forests of branching coral are gone. The pink conchs and Nassau grouper are mostly memories—the remaining few protected in U.S. waters, owing to their rarity. With care, there is a chance that these and many other species may recover, but some losses are irrecoverable. I missed meeting, for instance, one of Florida’s most charismatic animals, the Caribbean monk seal, a playful St. Bernard–size creature that once lolled on beaches throughout the region, sometimes ranging as far north as Galveston. The last one was sighted in 1952. It is now officially listed as extinct.

  During the week on Conch Reef this past July, I saw not even one lobster lurking under the ledges but was pleased to record the actions of numerous large barracuda, which were a constant presence above Aquarius, suspended midwater like sleek gray submarines. Several tarpon swept around the reef, always in motion, much like the dozen or so large permit that danced in glistening circles around the pillars under the lab. A few large black grouper and the awesome goliath made smaller species scatter when they loomed into view. Large barrel sponges and lumps of various hard corals nestled within a carpet of brown and green seaweed. Had I not personally witnessed the Key Largo reefs of fifty years before, I might have regarded this as a fine example of a thriving coral system, oblivious to what is now missing, and unaware that the beautiful, newly arrived lionfish and brilliant yellow cup corals on and near Aquarius are actually exotic species that are rapidly displacing natives.

  Scientists using Aquarius over the past twenty years have been able to document the decline of Conch Reef and have gathered information on the complexities of the system that will help us understand what has gone wrong. It will provide insight about what can be done to restore this and other reefs. Globally, about half of the coral reefs that existed when I was a child are gone or are in a state of serious decay. In the Caribbean region, including the Florida Keys, the loss is closer to 80 percent, linked to rising water temperatures and the combined effects of coastal development, overfishing, and pollution.

  The United States has been a leader in taking actions to address the decline of the health of natural systems; legislation enacted in the 1970s was aimed at protecting the air, water, coastal zones, endangered species, and marine mammals and—of special significance to the Florida Keys—making possible the designation of marine sanctuaries. In 1990, the year I was appointed chief scientist of the National Oceanic and Atmospheric Administration (NOAA), some 2,900 square nautical miles of waters surrounding the Florida Keys were designated as a marine sanctuary, a multiple-use managed area under NOAA’s administration.

  NOAA was formed as a special agency of the U.S. government within the Department of Commerce in 1970, the year I first lived underwater. On July 20, 1970, exactly one year after Neil Armstrong and Buzz Aldrin put their footprints on the moon, I emerged from the water after two weeks as a resident of a then-luxuriant reef in Lameshur Bay in the U.S. Virgin Islands—my first experience as an aquanaut. I was participating in part of a two-year program, Tektite I and II, sponsored by various agencies of the U.S. government, including NASA. Skylab and the International Space Station were years away when I successfully applied to be among the nation’s first “scientist-aquanauts.” At the time, no American women astronauts were allowed to fly; nor, as it turned out, were women thought to be appropriate candidates for becoming aquanauts.

  When I proposed to be part of a four-man, one-woman team to study the ecology of reefs where the Tektite lab was situated, there was great consternation, according to Dr. Jim Miller, the head of the project. “We didn’t expect women to apply,” he explained. “But several did, with qualifications every bit as good as those of the men. We weren’t sure how to handle it.”

  Even in the 1960s, men and women were tra
veling together on airplanes, sailing on ships, going on camping trips, riding long distances on trains—often using the same bathroom facilities. There were women senators, surgeons, pilots, university presidents, and CEOs of major corporations, but the U.S. government was cautious about having men and women live together for two weeks under the sea, with one bunkroom, one shower, and cameras observing everything that took place, 24/7.

  Jim Miller was instrumental in the decision to resolve this issue by forming an all-woman team. He was quoted as saying, “Well, half the fish are female, half the dolphins and whales. I guess we could put up with a few women as aquanauts.” Whatever the rationale, I was asked to lead a team of four scientists and one engineer, who had two weeks to conduct research projects and experience what it is like to cook, eat, sleep, take freshwater showers, use microscopes, and work inside quarters that resemble a comfortable trailer parked 50 feet underwater. Then, magically, we could step outside into the ocean for hours of exploration and research, breathing air from a double set of scuba tanks or rebreathers similar to the systems used by space-walking astronauts.

  I had logged—before the Tektite Project—more than a thousand hours using scuba and little submarines, but for the first time I began to see fish, sponges, corals, even shrimp as individuals, each one with features as distinctive as those of cats and dogs. I could recognize each of the several gray angelfish that lived near the lab, learned to expect when and where certain parrotfish would tuck in to sleep, and could identify some barracuda by their curious, unique behavior. Each had its place in the complex, thriving communities that made up the reefs, seagrass meadows, and open patches of sand that I explored day and night.

  As in New York or London or Singapore, it was obvious that it takes more than buildings to make the system work. The reef has its garbage collectors—sea cucumbers, crabs, goatfish among them. Cleaner fish and tiny shrimp provide critical “medical” services, removing parasites and neatly trimming away dead tissue from wounds. A healthy tension exists among predators and prey, with sharks, grouper, snapper, and other top carnivores keeping those lower down on the food chain in top form—lest they become snacks for those higher up.

  None of the women’s team had met prior to the mission except Ann Hurley and Alina Szmant, both doctoral candidates at the Scripps Institution of Oceanography. The oceanographer Renate True and I, both biologists, with Margaret Lucas, a graduate student engineer from the University of Delaware, completed the team. Many predicted that we would not get along or that, in more ways than one, we couldn’t handle the pressure (two and a half times that experienced at sea level). In fact, we bonded quickly and took seriously the unique opportunity to use the ocean as a laboratory. Our team averaged more time in the water than any others in the program, and despite the foreboding of some, we readily mastered the newly developed rebreather systems that made it possible to dive for as long as six hours with plenty of air to spare.

  Our success, we were later told, helped open the way for NASA to accept women as full-fledged astronauts, an unintended but welcome outcome of the Tektite program. Captain George Bond, the warm but gruff navy doctor who pioneered the concept of living underwater in the early 1960s, bluntly admitted that he was among those who opposed my participation, not as a woman, but as a mother of three small children. “But some of the aquanauts were fathers!” I huffed. “I know,” he said, reflecting an attitude that transcends logic. “But that’s different. A lot of things could have gone wrong, and no one wanted to lose a mother.”

  Some of the glory associated with astronauts rubbed off on the ten aquanaut teams (nine of them all male) in 1970, with a special media blitz focused on the “aquababes,” “aquabelles,” or, as one tabloid reported, “the aquanaughties.” (We mused about the reaction Apollo astronauts would have had if headlines referred to them as “astrohunks.”) As leader of the women’s team, I was asked to address Congress, lead a ticker-tape parade in an open limousine with Mayor Richard J. Daley down State Street in Chicago, and be the spokesperson for the project on hundreds of occasions—my baptism by fire as a scientist speaking to public audiences. Nothing I had done before as a scientist had attracted anything more than casual interest. Now millions of people wanted to know what it was like to live under the sea.

  I took pleasure in turning questions such as “Did you wear lipstick?” and “Did you use a hair dryer?” into a discourse on the importance of the ocean as our primary source of oxygen, the value of coral reefs, mangroves, and marshes as vital buffers against storms, and the delightful nature of fish, shrimp, lobsters, and crabs alive, swimming in the ocean—not just on plates swimming with lemon slices and butter.

  Sometimes I tell young women that I come from another planet, because the world I experienced during the first half of my life is so different from the relatively open attitudes about the role of women now prevalent in this country and around the world. My mother could not vote in the first two national elections held during her lifetime, when men of the same age could. As a graduate student, I was cheerfully told that all the coveted paid teaching assistantships would be given to men “because they would be wasted on women who would just get married and have kids.” Social changes have paralleled unprecedented advances in technology that have driven growth and the dissemination of knowledge. More has been learned about the nature of the ocean in the past fifty years, perhaps even the last thirty, than in all of preceding history.

  In 1961 President John F. Kennedy noted, “We are just at the threshold of our knowledge of the oceans . . . [This knowledge] is more than a matter of curiosity. Our very survival may hinge upon it.” The investments made in the decades that followed have forever altered the understanding of the ocean as the driving force underlying climate, weather, planetary chemistry—and, indeed, our “very survival.”

  Unknown until the late 1970s was the existence of deep-water hydrothermal vents gushing a hot soup of water, minerals, and microbes and fostering complex communities of creatures, including a previously unknown kingdom of microbes that synthesize food in the absence of sunlight and photosynthesis. No one attained access to the deepest sea until 1960, when two men descended to 35,797 feet (greater than the height of Mount Everest) in the submersible bathyscaphe Trieste for a brief glimpse of the deepest point on Earth—the Challenger Deep—in the Mariana Trench near Guam. And no one returned to those depths until March 2012, when the Canadian explorer and film director James Cameron ventured there in his personal one-man submersible.

  Technologies that enabled humans to go to the moon and send robots to Mars have given us a vitally important view of Earth from afar—a living blue jewel in a vast universe of unreachable, uninhabitable planets and stars, suspended in a seeming emptiness. On a cell phone or iPad or computer, ten-year-old children can now view Google Earth, zoom from space to their backyard, fly the Grand Canyon, and, starting in 2009, dive into “Google Ocean” to vicariously explore the depths of the sea. New methods of gathering, connecting, evaluating, and communicating data—of measuring change over time and projecting future outcomes based on knowledge no other species has the capacity to acquire—are all causes for hope, but the gains need to be approached with a healthy dose of caution. Even now, with all our advances, less than 5 percent of the ocean has been seen, let alone explored or mapped with the same precision and detail presently available for the moon, Mars, or Jupiter.

  The great conservationist Rachel Carson, who summed up what was known about the blue part of the planet in her 1951 book, The Sea Around Us, was unaware that continents move around at a stately geological pace or that the greatest mountain chains, deepest valleys, broadest plains, and most of life on Earth are in the ocean. Nor did she appreciate that technological advances developed for wartime applications were being mobilized to find, catch, and market ocean wildlife on an unprecedented scale, reaching distant, deep parts of the ocean no hook or net or trawl had ever touched before.

  “Eventually man . . . found his way b
ack to the sea,” she wrote. “And yet he has returned to his mother sea only on her terms. He cannot control or change the ocean as, in his brief tenancy of earth, he has subdued and plundered the continents.”

  In her lifetime—1907 to 1964—she did not, could not, know about the most significant discovery concerning the ocean: it is not too big to fail. Fifty years ago, we could not see limits to what we could put into the ocean or what we could take out. Fifty years into the future, it will be too late to do what is possible right now. We are in a “sweet spot” in time. Never again will there be a better time to take actions that can ensure an enduring place for ourselves within the living systems that sustain us. We are at an unprecedented, pivotal point in history, when the decisions we make in the next ten years will determine the direction of the next ten thousand.

  “If I could be anywhere . . . anywhere right now, I would want to be here,” croons the singer-songwriter Jackson Browne in a lilting tune he composed in 2010. Why here? Why now? Where would you choose, given the power to live on Mars, slip into the future, or glide back decades, centuries, or even millions or billions of years from our “here on Earth” and the twenty-first century’s now?

  Some might say anywhere but here and now! The world today is at war or on the brink of war. Weapons devised by humans can, in a single stroke, eliminate more people than existed on Earth in 1800. Poverty and hunger haunt hundreds of millions. The world economy is deeply troubled. Diseases are rampant. The natural systems that make life on Earth possible are in sharp decline on land, in the atmosphere above, and in the seas below. Earth’s natural fabric of life is in shreds, with consequences that threaten our own existence.