Deep Dive into Oceanography

Deep Dive into Oceanography

Oceanography is the study of all aspects of the ocean. Oceanography covers a wide range of topics, from marine life and ecosystems to currents and waves, the movement of sediments, and seafloor geology.


3 - 12+


Biology, Ecology, Chemistry, Earth Science, Geology, Oceanography, Geography, Geographic Information Systems (GIS), Physical Geography, Social Studies, World History

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Oceanography is the study of oceans. Oceanographers study how the ocean's processes affect each other. The chemistry of water, for example, affects which organisms can live in it. Meanwhile, organisms may change the structure of the seafloor.

There are four main types of oceanography. One is called marine biology. Oceanography also explores the chemistry, physics, and geology of the ocean.

Biological Oceanography

Biological oceanographers study marine plants and animals. They look at how the ocean environment affects living beings. Marine biologists are examples of biological oceanographers.

Biological oceanographers also study how species deal with changes in the environment. These changes may include pollution and warming waters. These scientists also study natural and human-caused disturbances. A natural disturbance might be a hurricane. An oil spill is an example of a man-made disturbance.

The Cetacean Sanctuary Research Project is a group that studies marine biology. It looks at marine life in the Mediterranean Sea, which is between Africa and Europe. The group focuses on whales and dolphins. By understanding these animals' behavior, oceanographers hope to protect the area.

Physical Oceanography

Physical oceanographers study physical ocean environments. They measure ocean temperature, waves, tides, and currents. They also focus on how different environments affect each other. These relationships have a big effect on the weather and climate.

Oceanographers in South Africa study the flow of water around the southern tip of Africa, for example. This flow is known as the Agulhas Current. Currents like these carry water all around the planet. They have a big effect on weather and climate.

Geological Oceanography

Geological oceanographers study the seafloor. They try to figure out how it forms and changes. These scientists also focus on the physical and chemical properties of rocks and sediments there. Sediment is matter that settles at the bottom of a lake, river, or ocean.

The ship called JOIDES Resolution has done many geological projects. It is used for international science research. It drills into the seafloor and brings samples to the surface for study. These samples give scientists clues about Earth's climate from the distant past. The ship also helps predict how changing climate may affect the ocean's future.

Chemical Oceanography

Chemical oceanographers study the chemistry of seawater. They seek to understand its effects on marine organisms. They also look at how the atmosphere and pollution affect water chemistry.

Ocean acidification is an important topic in chemical oceanography. The ocean is becoming more acidic. This change is happening because there is more and more carbon dioxide in the atmosphere. Some of this carbon dioxide mixes with the water and creates acid. Acid has a harmful effect on shellfish and corals.

Chemical oceanographers help the fishing industry. The Pacific Northwest of the United States has a large number of shellfish. Their numbers have dropped because of ocean acidification. Chemical oceanographers are trying to help shellfish growers. They want to help growers protect shellfish from acidification.

Oceanography through the Ages

Oceanography has a long history. It is deeply connected to human exploration, colonization, trade, and science.

Polynesians have been expert sailors for thousands of years. They migrated from the western coasts of the Pacific Ocean about 30,000 years ago. They colonized many islands, including Hawai'i. Polynesians used their knowledge of stars and ocean currents to guide their boats. The maps they made helped them navigate.

Starting in the 1400s, European explorers crossed the sea to colonize new lands. They found new trade routes for ships. Prince Henry of Portugal was nicknamed "Henry the Navigator." He created the first oceanographic institute. In this school, scholars and merchants learned about oceans, currents, and mapmaking.

All this knowledge helped launch the Age of Exploration. This was the period of history with explorers such as Christopher Columbus and James Cook. Their expeditions helped map the world's oceans. Important tools were invented or improved during this time. These include the compass, astrolabe, and chronometer. The astrolabe was used to measure how high stars were from the horizon. The chronometer was used to keep track of time.

A book, Science of the Sea, was published in 1912. It summarizes the results of the Challenger science expedition. The Challenger was a ship that traveled for thousands of kilometers between 1873 and 1876. Its goal was to gather information about the world's oceans. Many historians say this expedition was the beginning of modern oceanography. The scientists on this expedition made amazing discoveries using simple tools.

Military technology has also advanced the study of the oceans. The use of submarines led to sonar, for example. Sonar measures distance by looking at how long it takes for sound to travel. The sonar sends out sound waves from a ship or submarine. The sound waves bounce off of surrounding objects. The farther the object, the longer it takes for the sound to bounce back to the ship. Sonar helps scientists accurately measure the world under the sea.

Since the 1970s, satellites and computers have greatly advanced oceanography. They have helped scientists study the oceans on a global scale. In 1978, the U.S. space agency, NASA, sent the SEASAT satellite into space. The satellite's sensors measured wind, sea-surface temperature, and ice conditions. SEASAT also provided images of clouds, land, and water. It collected huge amounts of data.

The National Oceanic and Atmospheric Administration (NOAA) is a science group. It is an agency within the U.S. government. In the 1970s, NOAA set up a new system to study the ocean. Seventy floating devices were strung across the Pacific Ocean. These devices track temperatures, currents, and other data. They send the information to researchers. This system has improved our understanding of Earth's climate.

Oceanography Today

Today's oceanographers have more tools and technologies to do their research. These tools help them better understand marine environments. BIOMAPER is one example. This device is dragged behind a ship. It has been used to study small marine organisms. BIOMAPER uses five sonars that send out sound waves. It uses their echoes to calculate how large and how far away particles are. BIOMAPER can record data up to 500 meters (1,640 feet) deep.

BIOMAPER also measures water temperature and chemistry, which affect phytoplankton, zooplankton, and krill. Many marine animals feed on these tiny forms of sea life. The presence of plankton and krill tells us about the ocean's health.

JASON is a remote-controlled, deep-diving vessel. It allows scientists to explore the seafloor safely and more easily. Submarine dives are short and expensive. JASON, though, can explore underwater environments as deep as six kilometers (four miles). It can work for days on end.

JASON has a variety of instruments. Cameras and sonar map the seafloor. Two robotic arms allow scientists to collect samples of rocks, water, and sea life.

JASON's technology has been used for research and educational purposes. It has explored deep-sea environments that have never been seen before. It has also been used to find deep-sea shipwrecks. JASON's underwater images are sent to classrooms and its explorations are posted on the internet. This high-tech explorer gives the public a glimpse into the science of oceanography.

Fast Fact

After the Mutiny on the Bounty
In 1789, some of the crew of the British ship Bounty mutinied (rebelled) against the ship's leader, Lt. William Bligh. Bligh and 18 crew members loyal to him were set adrift in the South Pacific, a little southeast of the island of Tonga. Bligh and his crew were sent off in a seven-meter (23-foot)-long boat with food and water to last a few days, plus four cutlasses (swords), a sextant, and a pocket watch. They had no compass or navigational charts.

Bligh successfully navigated more than 6,500 kilometers (3,500 nautical miles) to the island of Timor in 47 days. Bligh's voyage to Timor is considered by many to be the most remarkable feat of navigation in history.

Fast Fact

Chart Error
Nautical charts that Christopher Columbus used when he set off from Spain showed nothing but ocean between him and eastern China. That's why his discovery of the Americas was such a lucky, lucky surprise.

Fast Fact

Crossing the Line
Sailors have elaborate rituals and celebrations when they cross the Equator, which they call crossing the line. Sailors who have never crossed the line are called pollywogs. Pollywogs are usually the target of embarrassing practical jokes.

Fast Fact

Oceanography is the study of marine environments and their impact on the surrounding area. Limnology is the study of freshwater environments. Some limnologists, especially those who study large bodies of water such as the Great Lakes, must often be familiar with oceanography as well.

Fast Fact

Oceanographers Are In Demand
According to the Bureau of Labor Statistics, job opportunities for oceanographers and other geoscientists are expected to grow by 18 percent in the next decade. The need for energy, environmental protection, and responsible land and water management will drive the creation of oceanography jobs, mostly in government and the oil industry.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Diane Boudreau
Melissa McDaniel
Erin Sprout
Andrew Turgeon
Mary Crooks, National Geographic Society
Tim Gunther, Illustrator
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
Educator Reviewer
Nancy Wynne
Expert Reviewer
David B. Eggleston, Center for Marine Sciences and Technology, North Carolina State University
National Geographic Society
Last Updated

October 19, 2023

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