The study of the ocean’s various features is known as oceanography. A vast range of subjects are covered by oceanography, including seafloor geology, currents and waves, marine life and ecosystems, and sediment transport.
Oceanography is an interdisciplinary field of study. The characteristics and functions of the ocean work together. The kinds of creatures that dwell in water are influenced by its chemical composition, for instance. In return, organisms contribute sediments to the seafloor’s geology. To investigate certain subjects or subdisciplines, oceanographers need to possess a comprehensive comprehension of these connections.
Subfields within Oceanography
The wide range of issues covered by oceanography can be broadly divided into four subdisciplines. A subdiscipline is a more focused area of study within a larger discipline or subject. The biological, physical, geological, and chemical processes that occur in the marine environment are the areas of expertise for oceanographers.
Biological Oceanography
The study of how oceanography’s subdisciplines interact to affect the distribution and abundance of marine plants and animals, as well as how marine creatures behave and evolve in response to their surroundings, is the focus of biological oceanographers. Biological oceanographers include fishery scientists and marine biologists.
The adaptation of organisms to environmental changes, such as rising pollution levels, warming waters, and man-made and natural disruptions, is another area of study for biological oceanographers. An underwater volcano erupting or a hurricane are examples of natural disturbances; overfishing or an oil spill are examples of anthropogenic disturbances.
The whale and dolphin species (cetaceans) that inhabit the Pelagos Sanctuary in the northwest Mediterranean Sea are the subject of the Cetacean Sanctuary Research Project, a marine biology initiative. These species are threatened by a variety of human activities, including heavy maritime traffic, urban pollution, and oil and gas exploitation. Oceanographers believe that by studying cetacean behavior in this high-pressure setting, they can save marine species found in the Pelagos and highlight their significance to the local coastal community.
Oceanographers track these species’ geographic location, migrations, and group size to gain a comprehensive understanding of them and their behavior. To learn more about how cetaceans interact with other marine animals and with one other, researchers record vocalizations, breathing patterns, and surface and aerial displays. Samples of skin and feces are examined to provide data on eating, drinking, and social behaviors. One of the largest data sets on marine animals in the Mediterranean Sea has been gathered by the Cetacean Sanctuary Research Project.
Biological oceanographers have more opportunities thanks to new technology. Marine resources are used in the field of marine biotechnology to create new industrial, medicinal, and ecological products.
Researchers can comprehend, extract, and create biological features of marine organisms through a technique known as biomimicry. Strong anti-cancer effects are exhibited by natural chemicals that are present in corals and other marine species. Superabsorbent materials that could be utilized to mop up oil spills are being produced using proteins found in bacteria and marine algae. Genetically modified marsh plants have been used to develop land crops that can withstand salt.
Since over 80% of all living things on Earth are marine species, the practical possibilities of this research are virtually limitless.
Physical Oceanography
In physical science, physical oceanographers investigate the connections between the bottom, coast, atmosphere, and physical characteristics of the ocean. They look into the currents, waves, tides, density, and temperature of the ocean. They also concentrate on how the ocean and Earth’s atmosphere combine to create our weather and climate systems.
For instance, oceanographers in South Africa have investigated the erratic water flow surrounding Africa’s southernmost point. The Agulhas Current, as it is commonly called, is a segment of a broader global water circulation system that is driven by factors such as density, wind, and currents. Physical oceanographers have discovered an increase in the Agulhas leakage, or the flow of water from the warmer Indian Ocean to the cooler Atlantic Ocean. There is a connection between global warming and the increased Agulhas leaking.
Climate and weather patterns will be drastically altered, according to physical oceanographers, and the ocean conveyor belt will slow down due to global warming. Sea levels rise as the ocean’s salinity and density decrease when ice caps melt. Sea levels rise more when ocean waters expand in response to warming.
Oceanography of Geology
The historical and contemporary makeup of seafloor formations is studied by geological oceanographers. They look into the beginnings of the underwater environment and describe its evolution and changes. The physical and chemical characteristics of the rocks and sediments that make up the seafloor are also a focus.
The multinational research vessel JOIDES Resolution has been used for several geological research missions. Under the ocean’s surface, Resolution gathers measurements and drills sediment-core samples. Researchers like this one can better comprehend our paleoclimate. The study of weather and climate trends spanning hundreds of millions of years is known as paleoclimatology. The seafloor’s ability to reflect variations in Earth’s climate makes it a valuable tool for climate prediction.
Oceanographers and other scientists on board the Resolution began studying the Louisville Seamount Trail, a chain of underwater volcanoes in the South Pacific near New Zealand, in December 2010. To comprehend the evolution of the hot zone that gave rise to these volcanoes, the ship dug sediment cores at six distinct locations. The findings of this study will contribute to our understanding of how landforms evolve.
Chemical Oceanography
The study of seawater’s chemical makeup and how it affects marine life, the atmosphere, and the bottom is the focus of chemical oceanographers. To comprehend how ocean currents transport water throughout the world—the ocean conveyor belt—they map the chemicals present in seawater. To demonstrate the critical function that the ocean plays in controlling greenhouse gases, such as carbon dioxide, which is a major contributor to global warming, chemical oceanographers investigate how the carbon from carbon dioxide gets buried in the seafloor. Chemical oceanographers also study the effects of pollution on the composition of salt water. They might research the peculiar and occasionally hazardous liquids emitted from ocean-floor hydrothermal vents.
One of the main concerns of chemical oceanography is ocean acidification. The rising levels of carbon dioxide in the atmosphere are making the ocean more acidic. Acid prevents calcium carbonate, which is the fundamental component of shells and corals, from forming.
Because of ocean acidification, shellfish populations in the United States Pacific Northwest have drastically decreased. Oregon’s chemical oceanographers assist shellfish farmers in modifying their practices to lessen the amount of acidic water entering the area. Additionally, they research to determine the point at which acidification does not affect shellfish. This study will supplement ongoing efforts to lessen the detrimental effects of ocean acidification on coral and shellfish habitats worldwide.
History of Oceanography
The histories of exploration, colonization, trade, conflict, and scientific discovery are closely linked to oceanography.
Polynesians, who are regarded as the first people to travel by sea, moved from the western Pacific Ocean coast about 30,000 years ago and settled on islands like New Guinea, Fiji, Samoa, and Hawaii.
Using their understanding of astronomy—the locations of stars and planets—and ocean currents, Polynesians were able to navigate the vast ocean. The first oceanographic maps were made with the use of these data. Islands were indicated by shells and knots, while the direction and power of the surrounding waves and currents were indicated by bent wood pieces. For more than 25,000 years, these stick charts were improved and passed down from generation to generation.
European explorers began using the sea to conquer new areas and create effective commerce routes in the 1400s. The first oceanographic institute was established by Prince Henry of Portugal, sometimes known as “Henry the Navigator,” to educate academics and traders about the oceans, currents, and mapmaking.
The Age of Exploration, which saw the start of global expeditions by European navigators and explorers like Ferdinand Magellan, Christopher Columbus, and James Cook, was spurred by these discoveries. During this time, significant oceanographic instruments were developed, such as the chronometer, astrolabe, and mariner’s compass. The chronometer significantly improved marine navigation by enabling sailors to determine their longitude while a ship was in motion.
A 1912 publication titled Science of the Sea provides an overview of the findings from the Challenger expedition (1873–1876), which many see as the forerunner of modern oceanography. The scientific conclusions drawn in this book are exceptional, even though they are based on scant or no data. A chart illustrating the rates at which sediment accumulates in the ocean, for instance, can be found in Science of the Sea. The quantity of shark teeth in a unit volume of silt served as the basis for the relative rates. When a sediment sample contained a large number of shark teeth, the pace of sediment buildup was noted as being extremely slow. When there were few shark teeth found, a very significant silt accumulation was noted. Members of the Challenger expedition accurately calculated the relative distribution of silt buildup in the ocean using this data!
Military Technologies and Satellite Innovations
Military technologies made ocean research easier. The invention of sonar and the magnetometer was spurred by the employment of submarines, which began during the American Civil War. By timing sound waves as they depart and return to a ship after bouncing off nearby objects, sonar detects distance. Compared to the rope depth soundings of the Challenger era, sonar allows scientists to estimate distances from the ocean’s surface to the seafloor more precisely and effectively. Oceanographers employ the magnetometer, which was first created to detect the metal hulls of submarines, to measure the seafloor’s magnetic properties. We now have a better knowledge of the Earth’s magnetic core thanks to these data.
Sophisticated computer technology has assisted oceanographers in measuring ocean parameters globally since the 1970s. The first civilian oceanographic satellite, called SEASAT, was launched by NASA, the US space agency, in 1978. The sea surface temperature, wind direction and speed, polar sea ice conditions, and surface waves were all recorded by SEASAT’s sensors. Satellite images of land, ocean, and clouds were also made available by SEASAT. SEASAT only lasted 105 days, yet in that time it gathered as much oceanographic data as ship-based exploration conducted over the preceding 100 years. The first maps of sea-surface temperature and ocean chlorophyll, a green pigment required for photosynthesis, were created by another NASA satellite called TIROS-N.
The National Oceanic and Atmospheric Administration (NOAA) of the United States started mooring buoys across the tropical Pacific Ocean in the late 1970s. This array of seventy buoys called the Tropical Atmosphere Ocean array, uses a satellite system to transmit real-time ocean and atmospheric data to the coast. Our capacity to forecast global climatic processes like El Nio has improved because of these data.
Current Oceanography
With the use of several instruments, oceanographers of today can explore, study, and characterize aquatic habitats. For instance, TowCam is specifically made to withstand the harsh conditions seen in the deep sea. The first digital camera device made specifically to capture sharp pictures of the seafloor is called TowCam. It may also gather samples of water, lava, and rock.
TowCam has been used to examine a variety of seafloor settings since it was completed in 2002, including the offshore regions of Taiwan and Iceland, the Galapagos Rift, the Gulf of Mexico, and the New England Seamounts. It has taken around 280,000 pictures and gathered over 300 samples of glass formed by volcanic eruptions. TowCam has enabled researchers worldwide to better understand underwater geology and volcanology by providing these visual and tangible samples.
BIOMAPER has been used to investigate phytoplankton, zooplankton, and krill in the Gulf of Maine and the Southern Ocean (as it is known to Australians) near Antarctica since its maiden dive in 1997. Five sonar devices are used by BIOMAPER to transmit various frequencies of sound waves. These frequencies reverberate back to the research unit after striking various-sized objects. These echoes are used by BIOMAPER to determine the size and distance of the particles. BIOMAPER can collect data at a depth of 500 meters (1,640 feet), in contrast to conventional nets that are limited to sampling areas up to five meters (16 feet).
In addition, BIOMAPER monitors the salinity, oxygen, light, and chlorophyll concentrations in the water. For phytoplankton, zooplankton, and Krill to develop, certain physical characteristics are crucial. Many marine species eat a significant portion of this minuscule sea life. Krill and plankton are regarded as indicator species of the general health of the ocean. Oceanographers can better understand the habitats and health of the open ocean by using BIOMAPER, which maps and measures the environment of this microscopic marine life.
With the help of JASON, a remotely operated deep-diving boat, scientists may effectively investigate the bottom. For days on end, JASON can be directed across underwater settings as deep as six kilometers (four miles), in contrast to brief and costly submarine excursions.
JASON records data and gathers materials using a range of equipment. The seafloor is mapped and captured by sonar, six color video cameras, and one still camera. Scientists can build and operate more research devices in addition to gathering samples of rocks, water, and marine life with the use of two robotic manipulator arms. The incredibly hot waters of hydrothermal vents can be collected in specially made water containers, which also help to maintain the chemical makeup of samples as they rise to the surface.
The technology developed by JASON has been applied to several research and teaching projects. It has studied the Pacific, Atlantic, and Indian Oceans’ hydrothermal vents. In addition, it has investigated other shipwrecks that were previously inaccessible to underwater archaeologists, recovering artifacts including tools and ceramics. The vessel provides the public with a unique window into deep-sea habitats by broadcasting photographs and reports to classrooms and the internet as part of the JASON project.