Oceanography is the study of the ocean’s physical, chemical, and biological features, as well as the ocean’s ancient history, current state, and future. The study of oceanography is more critical now than ever because the oceans are threatened by climate change and pollution, with entire species of marine life at risk of extinction. About 70 per cent of Earth’s surface is covered by water. Nearly 97 per cent of that water is saltwater swirling in the ocean. This is an important topic in geography. As a result, a thorough understanding of this subject is critical. is a critical concept in the UPSC exam syllabus.
As the name implies, Oceanography is the science of the oceans. Oceanography encompasses all oceanographic studies, from history to current climatic variations; chemistry to biological processes to products; origin to destruction; pollution to conservation. It is the study of the physical, ecological, geomorphic, and dynamic properties of the oceans.
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Oceanography Study Objectives
To differentiate between underwater formations, seawater composition, and qualities. Understanding the chemical, physical, geological, and biological processes that affect the surface of the ocean. To learn about oceanography because climate change, pollution, and other factors are threatening the ocean and its marine life.
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Oceanic Relief Features
Water covers approximately one-third of the earth’s surface. Oceans, Inland Seas, Small Enclosed Seas, Bays, and other hydrosphere features are classified according to their size and location as Oceans, Inland Seas, Small Enclosed Seas, Bays, and other hydrosphere features. The world’s four primary oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean. The Ocean Relief Features are different from the continental features because the oceanic crust is relatively newer compared to the continental features.
The oceanic crust is less than 70 million years old, whereas continental features are over 1 Billion years old. For academic simplicity, oceanic relief can be divided into four major divisions.
- The Continental Shelf
- The Continental Slope
- The Continental Rise
- The Abyssal plain
Besides these, there are many other associated Minor Relief features like ridges, hills, seamounts, guyots, trenches, canyons, etc.
Oceanic Relief Features result from the tectonic, erosional, depositional, and volcanic activities on the ocean surfaces. Ocean reliefs have a marked effect on the motion of the seawater, and they also impact human activities like fishing and navigation.
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Ocean Floor Diagram
In the figure given below, you can see the different relief features. The abyssal plain is the ocean floor. There are a few small deeper areas called ocean trenches beneath the ocean floor. Seamounts, volcanic islands, and mid-oceanic ridges and rises are examples of features rising from the ocean floor.
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Ocean Water Temperature and Density
Massive meteorology is concerned with the study of ocean temperatures because it deals with the portion of the atmosphere that spreads over vast water masses. One of the most important responsibilities of oceanographers has been to determine and accurately measure the temperature of the sea, as this aids in determining the motions of vast amounts of ocean water.
A substance’s density is defined as its mass per unit volume, expressed in grammes per cubic centimetre. Density is commonly used to refer to specific gravity, which is defined as the density to distilled water ratio at a given temperature and pressure. Pure water has a maximum density of one unit at 4 degrees Celsius; however, the density of the sea varies depending on the salinity content.
The density of pure water is determined solely by temperature and pressure. Temperature, pressure, and salinity all have an effect on seawater. This diagram depicts the effect of salt on density and freezing point. Pure water freezes at 0 degrees Celsius and has the highest density at 4 degrees Celsius, as shown in the image. The freezing point of ocean water decreases as salinity increases, as does the temperature of maximum density.
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Salinity is defined as the total amount of solid material in a kilogramme of seawater expressed in parts per thousand. The salinity of saltwater is 3.5 per cent on average, measured in parts per thousand. Salinity fluctuates due to winds caused by changes in air pressure.
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Ocean Water Movement
The ocean’s water is never still. Ocean water flows take various forms as a result of physical properties such as temperature, salinity, density, and so on. The movement of ocean water is influenced by external factors such as the sun, moon, and winds. The major movements of ocean waters are classified into three types. These are,
Ocean currents and waves are horizontal motions of ocean water, whereas tides are vertical flows of ocean water.
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Ocean Water regulates the Earth’s climate. The oceans play an important role in the hydrological cycle and are home to much of the world’s biodiversity. They provide food as well as minerals. They are a vital means of national defence as well as a low-cost mode of transportation.
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Above all, oceanographers can help predict future changes in global temperature and issue warnings about sea-level rise, which could harm low-lying countries and coral reefs. In this article, we discussed Oceanography and its relevance to the UPSC exam. We study the relief, temperature, density, salinity, and movement of ocean water through oceanography. Finally, we discussed the Significance of oceanography.