Oceanography

Summary

More than 70 percent of the Earth's surface is covered by saltwater oceans and seas. Oceanographers study a wide range of subjects, including major underwater geological formations, such as very high mountain ranges and very deep canyons, as well as the tectonic and volcanic movements that continue to change the submarine environment. They also study the plant and animal life in the world's oceans and analyze the chemical bodies—gases and minerals—in the waters.

Definition and Basic Principles

Oceanography is not a single applied science but rather a combination of fields of study. Because the oceans and seas of the world contain both living creatures and inanimate physical components, the basic sciences that contribute to oceanographic knowledge are marine biology, chemistry, and geology. However, the ecological effects caused by phenomena such as oceanic tides, currents, and temperature variations must be studied before the marine biologist, chemist, or geologist can obtain meaningful results from research.

Background and History

Since early historical times, people have been interested in the oceans and seas. For many centuries, attitudes toward the ocean were strongly influenced by superstition and mythology. Even as late as the publication of Jules Verne's Twenty Thousand Leagues Under the Sea (1873), depictions of the ocean depths were dominated by fantastic and mysterious images rather than based on science. Exactly when the study of oceanography became a science is hard to say, but each time technology allowed scientists to study the ocean at a greater depth, knowledge advanced significantly. As scientific knowledge of oceans and seas increased, people began to realize that a knowledge of geology and, to some extent, astronomy was valuable in understanding ocean phenomena.

The desire to develop submarines for use in warfare, particularly in World War I and II, spurred advances in ocean exploration. In the 1930s, Americans Otis Barton and William Beebe developed the bathysphere. A pressure-resistant spherical steel apparatus weighing 2,025 kilograms, the bathysphere could descend more than 900 meters, six times the depth that helmeted divers could reach. The bathysphere was connected to a ship on the surface by heavy cables and a hose that held electric and communication wires.

In 1951, Rachel Carson published The Sea Around Us, which popularized the study of oceanography. In her book, she focused on the vital interrelationships between submarine and surface phenomena and the delicate balance these relationships represent for the future of the world. Many of her concerns were adopted by later generations as the predominant issues confronting oceanography.

Another major figure who contributed to global recognition of the wonders of the oceans' secrets was the French oceanographer Jacques Cousteau. His contribution to knowledge of the undersea world began with the 1943 film Épaves (Shipwrecks), followed by his launch of the French navy's underwater research group. The navy group was the first of many to explore the ocean using methods developed by Cousteau and his team.

In 1953, Cousteau published The Silent World, describing his work as a diver and establishing the first scientific procedures for echolocation of large fish populations underwater. His accomplishments led to his appointment as director of the famous Oceanographic Institute and Museum in Monaco in 1957. Soon, he developed the SP-350, known as the diving saucer, which became a prototype for descending—with significantly improved maneuverability—to ever-deeper reaches. The SP-30 reached a depth of 500 meters in 1965. Although early developers of the bathysphere had descended to almost 250 meters in 1930 and to more than 900 meters in 1934, the limited maneuverability of their invention could not compare with that of Cousteau's diving vessel. Before Cousteau died in 1997, he and his associates witnessed major developments in fields of oceanography that they and others had pioneered.

How It Works

Measuring Tides. Perhaps more than any other area of oceanography, the study of ocean tides and waves requires knowledge from several fields of science. Principles of physics and astronomy, for example, help explain timing lapses and the strength of coastal tides. The rising and falling of tides are the result of gravitational pull from both the Moon and the Sun, and the strength and direction of tides are affected by forces connected with the Earth's rotation. Oceanographers may be involved in complicated mathematical calculations using the laws of physics to compare major tidal movements, while hundreds of relatively simple tidal gauge stations using float devices provide practical data for recordkeeping across the globe.

However, systematic data gathering may not be enough to predict potentially disastrous tsunamis or so-called monster waves in the middle of the ocean. Tsunamis are often caused by major earthquakes at fault points deep beneath the ocean surface. The earth's movements unleash swells that race toward coasts. Oceanographers measure the speed and forces of the tidal waves in an attempt to limit the damage when they reach the shore.

Oceanographers continue to investigate monster or rogue waves that appear rarely but suddenly on the high seas and pose significant threats to shipping. Rogue waves, which can be tall enough to sink ships, are thought to be the result of several tidal movements that come together at one location in mid-ocean and combine their forces.

Mapping Ocean Currents. Ocean currents can be at the surface or much deeper. The best known of the surface currents is the Gulf Stream, which can reach speeds of 300 centimeters per second, followed by the Kuroshio off the east coast of Japan. Westward-flowing currents north and south of the equator (caused mainly by the trade winds over tropical regions of the Atlantic, Pacific, and Indian oceans) are separated by a 300-meter-wide countercurrent moving eastward. Several major deep-ocean currents, which have both lateral and vertical patterns of movement, are very challenging for oceanographers. To study these currents, oceanographers use instruments to locate underwater strata that differ either in temperature or levels of saline (or other chemicals). They use these data to attempt to explain why massive volumes of water either drop or rise, displacing other bodies and creating currents in the depths of the ocean.

Surveying the Ocean Floor. Two obvious and spectacular applications of geology to oceanography are the study of deep trenches and mid-ocean mountain ridges. For example, the Mariana Trench north of New Guinea is more than 2,542 kilometers long and, in places, 69 kilometers wide. At its deepest point, the Challenger Deep, the Mariana Trench plunges to more than 10,924 meters below sea level. The Mid-Atlantic Ridge (discovered in 1872) rises from more than 2,000 meters below sea level to form island mountains more than 2,000 meters high (notably in Iceland and the Azores).

Less spectacular but of considerable practical importance is the study of the continental shelves. Oceanographic studies of coastal ocean zones contribute increasingly to key economic development schemes, most notably (but with increasingly controversial environmental implications) in seeking zones for commercial exploitation of undersea petroleum reserves.

How El Niño Works. Although oceanographers are still investigating the phenomenon of El Niño (part of the larger El Niño-Southern Oscillation (ENSO) pattern), certain facts have been established. When there is area-wide warming (El Niño conditions) or cooling (La Niña conditions) of surface waters in the Equatorial Pacific occurring at the same time that atmospheric pressure causes surface waters of the western Pacific to rise or fall (the Southern Oscillation), major climatic repercussions occur in the subtropical eastern Pacific. These conditions may bring extreme drought or excessive rain. The reasons for the ocean-wide coupling of this cause-and-effect situation are not clear. Oceanographers estimate that the phenomenon recurs in cycles of about five to seven years.

Applications and Products

Harvesting Microscopic Organisms. Oceanographers have increasingly directed their attention to microscopic plant and animal organisms, particularly to the smallest forms of plankton in the food chain and multiple varieties of algae. Extremely tiny and exponentially numerous holoplankton (as distinct from meroplankton, which are mainly tiny larvae that become larger independent organisms such as jellyfish, sea urchins, and starfish) never develop sufficient motor independence to propel themselves and instead drift like clouds in the world's seas and oceans. Concentrated masses of plankton provide nourishment to many varieties of fish, which in turn are eaten by larger fish. Therefore, oceanographers—as potential sources of information for the fishing industry—focus on studying not only the temperatures and saline/chemical content that contribute to plankton propagation but also the currents that can transport them to different areas of the ocean, creating concentrated feeding grounds for larger, commercially desirable fish species.

Commercial Uses of Algae. Oceanographers have contributed information to industries wishing to control the growth of certain species of algae. Industrially organized algae cultivation is already used to produce fertilizers and feed for livestock, dyes, and pharmaceuticals. In general terms, algae (larger forms of which are called seaweed) are plant plankton that, like all plants, use photosynthesis to convert carbon dioxide into various organic compounds and, most importantly, for the environment, into oxygen. Algae's ecologically important role as an oxygen producer and its potential as a fuel source pose challenges for oceanographers. They are likely to be called on to identify the most relevant species for various industrial uses and the optimal conditions for their propagation under controlled conditions.

Careers and Course Work

Individuals interested in preparing for a career in oceanography should plan their education carefully and consider the employment paths likely to be open at various levels. It is generally recommended that undergraduates focus on the core sciences (such as biology and chemistry) and mathematics. For some entry-level jobs relating to oceanography, an undergraduate degree with a heavy emphasis on science may meet the basic requirements. Those seeking Master's or Doctoral degrees, however, must attend a university offering a graduate program in specialized subareas of oceanography, such as biological, chemical, geological, or physical oceanography. A Master's degree or Doctorate in a subarea of oceanography is required to work in academic institutions (as teachers or researchers), private companies with involvement in various maritime economic pursuits, international or national organizations involved in oceanography, a variety of governmental agencies involved in environmental issues, and certain branches of the military.

Several specifically defined areas are likely to attract the professional expertise of oceanographers in the future. Several of these are connected with growing environmental concerns, while others are more clearly tied to changing economic markets. Environmental concerns include climate change and global warming issues and questions regarding the disposal of industrial and agricultural wastes. Increasingly, corporations are turning to oceanographers to develop ways to exploit the ocean waters. For example, fish farming based on scientifically grounded methods plays an ever-expanding role as world demand grows for common edible seafood. Industrial extraction of minerals and the development of the oceans' biomedical and pharmaceutical resources will require various oceanographic technical skills to guarantee proper responses to ecological and health safety concerns.

The primary US government agency concerned with oceanographic issues is the National Oceanic and Atmospheric Administration (NOAA). There are also numerous private-sector research organizations and professional associations of interest to oceanographers. Three of the most famous research institutes in the United States are the Scripps Institution of Oceanography in La Jolla, California; the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts; and the Lawrence Berkeley National Laboratory in Berkeley, California. Professionals in these institutes (together with their fellows in many other private research organizations) continue to play significant roles in defining the new frontiers of oceanography.

A variety of private companies that employ oceanographers (such as the Woods Hole Group, General Oceanics, and Sound Ocean Systems) share contracts and research projects with Scripps and Woods Hole, as well as similar research institutions in other countries. Those interested in career possibilities in oceanography should familiarize themselves with professional associations or interest groups whose members are oceanographers. These include the Consortium for Oceanographic Research and Education in Washington, DC; the Reef Environmental Education Foundation in Key Largo, Florida; the Atlantic Coastal Zone Information Steering Committee in Halifax, Nova Scotia; and the National Geographic Society in Washington, DC.

Social Context and Future Prospects

Several socially relevant issues are likely to involve professional oceanographers. Several of these are connected with growing environmental concerns, and others are tied to changing economic markets. In the first area, global climate change and questions about industrial waste disposal rank very high. Rising concerns around the world over the effects of pollution on oceanic ecosystems suggest that very aggressive conservationist movements (such as Greenpeace) are likely to be joined by an increasingly broad spectrum of environmental organizations focused on the world's oceans and seas.

Meanwhile, economically attractive activities involving controlled ocean water exploitation already involve oceanographers in critical areas that seemed only marginally important before the twenty-first century. Scientifically based fish farming, for example, is growing in importance as demand for seafood increases. Conservationists hope that fish farms will decrease pressures on the natural habitat of many commercially attractive species. Also, oceanographers will likely need to create better ways to extract minerals from the world's oceans and develop marine pharmaceutical resources without damaging the environment.

Because ecological and climate issues are being recognized as vital for the future of the planet, oceanographic research projects are being conducted in these areas. The world's oceans have gotten increasingly hotter each year in the 2020s, and programs that study such climate issues are needed. Such programs include NOAA's Climate Variability and Predictability program, which seeks to find the causes of climate variability, and the Integrated Ocean Drilling Program, an international organization that studied the history of the Earth through rocks and sediments beneath the ocean floor. The program undertook fifty-two missions before being phased out in 2013 and replaced with the International Ocean Discovery Program (IODP). NOAA's Sustainable Seas Expeditions were five-year programs that explored various marine ecosystems. High-tech environmental research projects included the Surface Heat Budget of the Arctic Ocean (SHEBA) of the National Center for Atmospheric Research's Earth Observing Laboratory, which investigated the relationship between the Arctic ice pack and climate.

The development of remotely operated vehicles, greatly expanded since the 1980s, has made it possible to penetrate ocean depths and regions that were unreachable by undersea devices carrying people. In the 2010s, the Woods Hole Oceanographic Institution developed a hybrid remotely operated vehicle called the Nereid Under Ice to explore beneath the ice-covered seas of the Arctic. Studying Arctic Sea ice is especially important because it helps inform climatologists who are studying the rapidly disappearing glaciers of the Arctic and its impacts on the under-ice ecosystem of Arctic plants and animals. The Nereid Under Ice was built to travel great distances—up to twenty-five miles—to explore this hard-to-reach area.

Oceanographers continue to innovate and make discoveries. In the twenty-first century, new oceanic species continued to be discovered, especially in the deep sea. Oceanographers studied the movement and migration of sea creatures in hopes of inspiting innovations to remote and crewed vehicles. Digital maps and representations of the ocean also aided oceanographers in better understating the world's oceans.

Bibliography

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