Oceanography is the study of the ocean, and covers a wide range of topics. The field includes research on marine life and ecosystems. It also includes the science of water currents, waves, and seafloor geology.

Oceanographers study how the ocean's processes relate to each other. The chemistry of water, for example, affects which organisms can live in it. In turn, organisms may affect the geology of the seafloor.

Oceanography is divided into four main areas, and oceanographers usually specialize in one of them. These areas are called biological, physical, geological, and chemical oceanography.

Biological Oceanography

Biological oceanographers study marine plants and animals. They research how the ocean environment affects living beings. Marine biologists and scientists who work in fisheries are examples of biological oceanographers.

Biological oceanographers also study how species adapt to environmental changes. These changes may include increased pollution and warming waters. Oceanographers also investigate natural and artificial disturbances. A hurricane is an example of a natural disturbance. An oil spill is an example of an artificial, or man-made, disturbance.

The Cetacean Sanctuary Research Project is a marine biology program. It is carried out in the Mediterranean Sea. It focuses on cetaceans, or whale and dolphin species. By analyzing these animals' behavior, oceanographers hope to protect the area's marine life.

Physical Oceanography

Physical oceanographers study the relationship between marine environments. These environments include the atmosphere, seafloor, coastlines, and the ocean itself. These scientists investigate ocean temperature, waves, tides, and currents. They also research the many ways the ocean interacts with Earth's atmosphere. These interactions have a big influence on weather and climate systems.

Oceanographers in South Africa, for example, study the flow of water around the southern tip of Africa. This movement is known as the Agulhas Current. It is part of a larger "ocean conveyor belt" of currents. These currents carry water around the globe.

Physical oceanographers are studying how global warming is affecting ocean currents. They believe global warming will slow the ocean conveyor belt. It could cause big changes in climate and weather patterns.

Geological Oceanography

Geological oceanographers investigate the seafloor. They study the underwater landscape and its changes. They also focus on the physical and chemical properties of rocks and sediments found there. Sediment is matter that settles at the bottom of a lake, river, or ocean.

Various geological research projects have been carried out by the JOIDES Resolution. Resolution is an international research vessel. It drills into the seafloor and collects samples. This research assists scientists in understanding Earth's climate from the distant past. It also helps predict how changes in the climate will affect the ocean's future.

Chemical Oceanography

Chemical oceanographers study the chemistry of seawater. They aim to understand its effects on marine organisms. They also study its interactions with the atmosphere and seafloor. Chemical oceanographers study how the carbon from carbon dioxide is buried in the seafloor. This work highlights the key role the ocean plays in controlling the amount of carbon dioxide. Carbon dioxide is a greenhouse gas in the atmosphere. It contributes to global warming. Chemical oceanographers also study how pollution affects seawater.

Ocean acidification is another important topic in chemical oceanography. The ocean is becoming more acidic. This change is due to the increased amount of carbon dioxide in the atmosphere and oceans. Some of the carbon dioxide creates acid when it mixes with the ocean water. Acid has a negative effect on the growth of shellfish and corals.

The Pacific Northwest region of the United States has a large shellfish population. The number of shellfish has dropped because of ocean acidification. Chemical oceanographers help shellfish growers take care of these animals, and they hope to find ways to reduce the effects of ocean acidification.

Oceanography through the Ages

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

Polynesians are considered the world's first seafarers. Their ancestors migrated from the western coastline of the Pacific Ocean about 30,000 years ago. They colonized islands such as Fiji, Samoa, and Hawai'i. Polynesians used their knowledge of ocean currents and the positions of stars and planets. Their mastery helped them navigate in the open ocean.

Starting in the 1400s, European explorers used the sea to colonize new lands. They also established 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.

These new studies helped bring about the Age of Exploration. Many famous European explorers came from this period. It includes such explorers as Christopher Columbus, Ferdinand Magellan, and James Cook. Their expeditions helped map the world's oceans and better understand them. Important oceanographic tools were created and improved upon during this period. They included the compass, astrolabe, and chronometer. The astrolabe was used to measure how high stars were from the horizon. Chronometers allowed sailors to keep track of time, and figure out the ship's position.

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 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 that took part made remarkable discoveries using simple science tools.

Military technology also aided the study of our oceans. The use of submarines led to the development of sonar, for example. Sonar measures distance by timing sound waves. These sound waves leave and return to a ship after bouncing off surrounding objects. Sonar helps scientists accurately measure the undersea world.

Since the 1970s, satellite and computer technologies have greatly advanced the science of oceanography. They helped oceanographers study oceans on a global scale. In 1978, the U.S. space agency NASA launched the SEASAT satellite. Its sensors measured wind, sea-surface temperature, and polar sea-ice conditions. SEASAT also provided images of clouds, land, and water. This satellite was active for only 105 days. However, it collected vast amounts of oceanographic data.

The National Oceanic and Atmospheric Administration (NOAA) is a science agency within the U.S. government. In the late 1970s, NOAA set up a new system of monitors. It was known as the Tropical Atmosphere Ocean array. Seventy floating devices were anchored across the Pacific Ocean. This system sends data to labs on the shore almost instantly. It has improved our ability to analyze and predict changes in world climate.

Oceanography Today

Modern oceanographers are able to use a growing variety of tools and technologies. These tools help them better understand marine environments. BIOMAPER, a device towed behind a ship, is one example. Since its first dive in 1997, BIOMAPER has been used to study small marine organisms. It 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. These physical properties are important for phytoplankton, zooplankton, and krill, which are small sea organisms. Many marine animals rely on this tiny sea life for food. Plankton and krill are considered species that indicate the ocean's overall health.

JASON is a remote-controlled, deep-diving vessel. It allows scientists to explore the seafloor safely and efficiently. Submarine dives are short and expensive. JASON, though, can be guided through underwater environments up to six kilometers (four miles) deep. It can work for days on end. The vessel also has various instruments. It can map the seafloor with six color video cameras, one still camera, and sonar. Its two robotic arms allow scientists to collect samples of rocks, water, and sea life.

JASON's technology has been used for both research and education. It has been used to study hydrothermal vents deep in the ocean. Hydrothermal vents are cracks in the seafloor that shoot out hot water. JASON has also been used to find shipwrecks. The vessel sends images and reports to classrooms, and its research is posted on the internet. This allows the public a rare glimpse into deep-sea environments.