Understanding Oceanography: A Comprehensive Guide for Enthusiasts

Oceanography is a fascinating and broad field of study that encompasses the scientific exploration of the world’s oceans. It covers various aspects such as physical, chemical, biological, and geological properties of the ocean. Here’s a detailed overview:

What is Oceanography?

Oceanography, also known as marine science, is the study of the physical, chemical, biological, and geological aspects of the ocean. It encompasses everything from the microscopic organisms living in the ocean depths to the large-scale processes that shape ocean currents and climate. The field is critical for understanding the Earth’s environmental systems and for managing the many resources that the ocean provides.

Oceanography History 

The study of the oceans has a long and storied history, dating back to ancient civilizations. The Greeks and Romans made early observations about the sea, and maritime cultures around the world developed extensive knowledge of local oceanic conditions.

Also Read: Exploring the Depths of Space: A Journey through Space Science Missions

The Age of Exploration, beginning in the 15th century, saw significant advancements in oceanography as European explorers mapped coastlines and ocean currents. Figures such as Captain James Cook made important contributions with their detailed charts and observations. In the 19th century, scientific expeditions like the voyage of HMS Challenger from 1872 to 1876 laid the groundwork for modern oceanography by systematically measuring ocean depths, temperatures, and biological samples.

Branches of Oceanography

Oceanography is divided into several sub-disciplines, each focusing on different aspects of the ocean:

1. Physical Oceanography: This branch deals with the physical properties and processes of the ocean. It includes the study of waves, tides, ocean currents, and the interaction between the ocean and the atmosphere. Physical oceanographers are interested in understanding how these processes affect climate, weather, and the distribution of heat and nutrients in the ocean.
2. Chemical Oceanography: This sub-discipline focuses on the chemical composition of seawater and the chemical interactions that occur within the ocean. Chemical oceanographers study the cycles of elements such as carbon and nitrogen, the chemistry of oceanic particles, and the impact of pollutants. They also examine how ocean chemistry is linked to biological processes and climate change.
3. Biological Oceanography: Biological oceanographers study the organisms that live in the ocean and their ecological interactions. This includes everything from tiny plankton to large marine mammals. Research in this field covers the distribution and abundance of marine life, the productivity of oceanic ecosystems, and how marine organisms adapt to their environments.
4. Geological Oceanography: This branch is concerned with the structure and composition of the ocean floor. Geological oceanographers study processes such as plate tectonics, underwater volcanism, and sedimentation. They also explore the history of the ocean basins and how they have changed over geological time scales.

Oceanography: Oceans of the World

The world’s oceans are vast and interconnected, covering more than 70% of the Earth’s surface. They are traditionally divided into five major oceans:

1. Pacific Ocean

• Area: More than 63 million square miles (165 million square kilometers).
• Depth: Deepest point is the Mariana Trench, reaching 36,000 feet (10,973 meters).
• Tectonics: Home to the “Ring of Fire,” an area with a high concentration of earthquakes and active volcanoes.
• Biodiversity: Rich in marine biodiversity, including coral reefs, fish, and marine mammals.
• Climate Influence: Influences global weather patterns, including El Niño and La Niña phenomena.
• Islands: Contains many island nations and territories, such as Japan, the Philippines, and Fiji.
• Trade Routes: Important for international trade, with major shipping routes passing through.
• Resources: Rich in resources like fish, oil, and natural gas.

2. Atlantic Ocean

• Area: About 41 million square miles (106 million square kilometers).
• Depth: Deepest point is the Puerto Rico Trench, reaching about 28,000 feet (8,486 meters).
• Divisions: Split into North and South Atlantic by the equator.
• Climate Influence: Plays a key role in the Atlantic Meridional Overturning Circulation (AMOC), affecting global climate.
• Historical Significance: Vital for exploration, colonization, and the triangular trade during the Age of Exploration.
• Biodiversity: Hosts diverse ecosystems, including coral reefs, sea grass beds, and open ocean environments.
• Economy: Major fishing grounds and petroleum extraction areas.
• Maritime Boundaries: Borders numerous countries, contributing to economic and political significance.

3. Indian Ocean

• Area: Around 27 million square miles (70 million square kilometers).
• Depth: Deepest point is the Java Trench, reaching about 25,000 feet (7,725 meters).
• Climate: Influences the monsoon climate, critical for agriculture in surrounding countries.
• Trade: A major route for oil and cargo shipping, linking the Middle East, Africa, and Asia.
• Biodiversity: Rich marine life, including unique species in coral reefs and deep-sea habitats.
• Geopolitical Importance: Strategic location with key maritime chokepoints like the Strait of Hormuz and the Malacca Strait.
• Islands: Includes island nations like Madagascar, the Maldives, and Sri Lanka.
• Resources: Extensive oil and gas reserves, as well as valuable mineral deposits on the seabed.

4. Southern Ocean

• Area: Encircles Antarctica, covering about 8.4 million square miles (21 million square kilometers).
• Depth: Average depth is around 13,100 feet (4,000 meters), with the deepest point being the South Sandwich Trench at about 24,000 feet (7,236 meters).
• Currents: Dominated by the Antarctic Circumpolar Current, the strongest ocean current in the world.
• Climate Regulation: Plays a crucial role in regulating Earth’s climate by acting as a heat and carbon sink.
• Marine Life: Supports unique ecosystems with species like the Antarctic krill, penguins, and whales.
• Ice Coverage: Characterized by extensive ice shelves and sea ice, which vary seasonally.
• Research: Important for scientific research on climate change, marine biology, and glaciology.
• Conservation: Subject to international treaties like the Antarctic Treaty System, which regulates activities to protect the environment.

5. Arctic Ocean

• Area: The smallest ocean, covering about 5.4 million square miles (14 million square kilometers).
• Depth: Average depth is around 3,953 feet (1,205 meters), with the deepest point being the Fram Basin at about 15,305 feet (4,665 meters).
• Ice Coverage: Covered by sea ice for most of the year, with significant seasonal variations.
• Climate Sensitivity: Highly sensitive to climate change, with rapidly melting ice affecting global sea levels.
• Biodiversity: Home to species adapted to cold environments, such as polar bears, seals, and Arctic cod.
• Resources: Rich in oil, natural gas, and minerals, making it a focus of geopolitical interest.
• Navigation: Increasingly navigable due to melting ice, opening new shipping routes like the Northwest Passage.
• Indigenous Peoples: Inhabited by indigenous communities with unique cultures and lifestyles adapted to the Arctic environment.

Oceanography: Relief of the Ocean Floor

The ocean floor is as varied and complex as the continents. It includes several major features which are:

1. Continental Shelf

• Definition: The extended perimeter of each continent, submerged under relatively shallow water.
• Depth: Typically extends from the shore to depths of about 200 meters.
• Width: Can vary significantly, from a few kilometers to over 1,000 kilometers.
• Marine Life: Rich in biodiversity, hosting various species of fish, corals, and other marine organisms.
• Resources: Abundant in natural resources like oil, gas, and minerals, making it a significant area for resource extractiona.
• Economic Importance: Vital for fisheries, tourism, and maritime activities.
• Environmental Protection: Subject to conservation efforts to protect habitats and marine life from overexploitation and pollution.

2. Continental Slope

• Definition: The steep slope descending from the edge of the continental shelf to the abyssal plain.
• Depth Range: Typically between 200 meters to 3,000 meters.
• Gradient: Much steeper than the continental shelf, with gradients between 4 to 6 degrees.
• Geological Features: Characterized by submarine canyons, formed by ancient river systems or underwater landslides.
• Sediment Transport: Acts as a conduit for sediments moving from the continental shelf to the deep ocean.
• Research Importance: Important for studying sedimentary processes, plate tectonics, and potential resource deposits.

3. Abyssal Plains

• Definition: Flat, deep-ocean floors that cover more than 50% of the Earth’s surface.
• Depth: Typically found at depths between 3,000 and 6,000 meters.
• Formation: Created by the deposition of fine sediments like clay and silt over millions of years.
• Topography: Among the flattest and smoothest regions on Earth.
• Biodiversity: Home to unique deep-sea ecosystems adapted to high pressure and low light conditions.
• Scientific Significance: Crucial for understanding deep-sea ecology, biogeochemical cycles, and the history of ocean basins.
• Human Impact: Increasingly explored for potential mining of polymetallic nodules and other resources.

4. Mid-Ocean Ridges

• Definition: Underwater mountain ranges formed by tectonic plate movements, particularly seafloor spreading.
• Extent: The global mid-ocean ridge system spans about 65,000 kilometers (40,000 miles).
• Example: The Mid-Atlantic Ridge is one of the most well-known, running down the center of the Atlantic Ocean.
• Seafloor Spreading: Sites where new oceanic crust is formed as magma rises from the mantle and solidifies.
• Hydrothermal Vents: Features like black smokers and white smokers found at ridges, releasing mineral-rich water and supporting unique ecosystems.
• Volcanic Activity: Frequent volcanic eruptions contribute to the formation of new seafloor and topographic changes.
• Biodiversity: Hosts specialized life forms that thrive in extreme conditions, relying on chemosynthesis instead of photosynthesis.

5. Ocean Trenches

• Definition: Deep, narrow depressions in the ocean floor, formed by the subduction of one tectonic plate beneath another.
• Depth: The Mariana Trench is the deepest part of the world’s oceans, reaching depths of over 36,000 feet (about 11,000 meters).
• Geological Activity: Sites of intense geological activity, including earthquakes and volcanic eruptions.
• Subduction Zones: Key areas where oceanic plates are forced down into the mantle, recycling Earth’s crust.
• Ecosystems: Home to unique biological communities adapted to extreme pressures and low temperatures.
• Scientific Exploration: Important for understanding plate tectonics, earthquake processes, and the limits of life on Earth.
• Human Impact: Some trenches are targeted for deep-sea mining, raising concerns about environmental impacts.

Some other minor relief feature are: 

1. Seamounts: These are underwater mountains that rise from the ocean floor but do not reach the surface. They are often formed by volcanic activity and can support diverse marine life.
2. Guyots: Similar to seamounts, guyots are flat-topped underwater mountains. They were once above sea level and have been eroded by wave action.
3. Oceanic Plateaus: These are large, relatively flat elevated areas of the ocean floor. They are typically composed of thickened crust and can be formed by volcanic activity or tectonic processes.
4. Abyssal Hills: These are small, rolling hills found on the abyssal plains. They are among the most common topographic features on the ocean floor and are usually less than 1,000 meters in height.
5. Ridges and Rises: Smaller than mid-ocean ridges, these features are elongated elevations on the ocean floor. They are formed by tectonic activity and can be found in various parts of the ocean.

Oceanography: Physical Properties of Ocean Waters

The physical properties of seawater are influenced by temperature, salinity, and pressure:

Temperature

• Variation: Temperature varies with depth and location; surface waters are warmer due to solar heating, while deeper waters are colder.
• Impact on Density: Temperature affects the density of ocean water; warmer water is less dense and tends to stay at the surface, while colder water is denser and sinks.
• Thermocline:
  • Definition: The thermocline is a distinct layer in a body of water where the temperature changes rapidly with depth.
  • Function: It separates the warmer, mixed surface water from the cooler, deep water below, acting as a barrier to mixing.
  • Location: More pronounced in tropical regions where surface waters are much warmer; less distinct in polar regions where surface and deep water temperatures are closer.
  • Seasonal Variations: In temperate regions, the thermocline can be more pronounced in summer and may weaken or disappear in winter.

Salinity

• Definition: Salinity is the concentration of dissolved salts in seawater, typically measured in parts per thousand (ppt).
• Average Salinity: Average ocean salinity is about 35 ppt but can vary in different regions.
• Factors Affecting Salinity:
  • Evaporation: Increases salinity as water evaporates and leaves salts behind.
  • Precipitation: Decreases salinity by diluting seawater with freshwater.
  • River Inflow: Lowers salinity near river mouths.
  • Ice Formation/Melting: Ice formation increases salinity by leaving salts behind; melting ice decreases salinity by adding freshwater.
• Halocline:
  • Definition: The halocline is a water layer where salinity changes rapidly with depth.
  • Function: It separates water masses with different salinities, affecting water density and circulation.
  • Influence on Marine Life: Influences marine life and oceanographic processes, especially in estuaries and coastal regions where freshwater mixes with seawater.

Density

• Factors Influencing Density: Temperature, salinity, and pressure.
  • Temperature Influence: Colder water is denser; warmer water is less dense.
  • Salinity Influence: Higher salinity increases density.
  • Pressure Influence: Density increases with depth due to rising pressure.
• Stratification: Denser water tends to sink, creating stratification in the ocean layers.
  • Thermohaline Circulation: Density-driven global ocean current system, essential for nutrient transport and climate regulation.
  • Impacts on Ocean Circulation: Stratification impacts ocean circulation and the distribution of nutrients.
  • Seasonal and Regional Variations: Density variations contribute to seasonal mixing, upwelling, and downwelling, crucial for nutrient cycling and productivity in marine ecosystems.

Light Penetration

• Decreases with Depth: Light penetration decreases with depth, affecting the distribution of marine life.
• Photic Zone: The photic zone, where light is sufficient for photosynthesis, extends to about 200 meters.
  • Photosynthesis: Most primary production occurs in this zone due to the availability of light.
• Aphotic Zone: Below the photic zone, less light is available, and the types of organisms that can live there change.
  • Adaptations: Marine organisms in the aphotic zone have adapted to low-light conditions, often through bioluminescence or enhanced sensory organs.

Oceanography: Movement of Ocean Waters

Ocean waters are constantly in motion due to various forces:

1. Waves: Created by the wind blowing over the surface of the ocean. They transfer energy and can vary in size. Waves play a crucial role in coastal processes and can affect marine and coastal ecosystems.
2. Tides: The rise and fall of sea levels caused by the gravitational pull of the moon and the sun. Tides follow a predictable pattern and are crucial for coastal ecosystems. They also influence human activities such as navigation.
3. Currents: Ocean currents are large-scale water movements driven by wind, density differences, and the Earth’s rotation. They play a vital role in distributing heat and nutrients around the globe. Surface currents are primarily driven by wind, while deep-water currents are driven by density differences.
4. Thermohaline Circulation: Also known as the global conveyor belt, this deep-ocean current is driven by differences in water density due to temperature and salinity. It plays a critical role in regulating the Earth’s climate by transporting heat and nutrients across the globe.

Oceanography: Significance of Oceans

Oceans are vital for the planet’s health and human well-being:

1. Climate Regulation: Oceans absorb and store vast amounts of heat, helping to regulate the Earth’s climate. They also play a key role in the carbon cycle by absorbing carbon dioxide from the atmosphere.
2. Biodiversity: Home to a diverse range of species, from microscopic plankton to the largest whales. Marine ecosystems provide critical habitat and support complex food webs.
3. Economy: Oceans support tourism and maritime trade, providing jobs and income for millions of people. Coastal and marine resources contribute significantly to the global economy.
4. Resources: Oceans offer resources such as oil, natural gas, and minerals. They also hold potential for renewable energy sources like wind, wave, and tidal power.
5. Carbon Sink: Oceans absorb a significant portion of the carbon dioxide emitted by human activities, helping to mitigate climate change. However, this also leads to ocean acidification, which can have harmful effects on marine life.

Oceanography: Conventions and Laws on Ocean

International conventions and laws govern the use and protection of the oceans:

1. United Nations Convention on the Law of the Sea (UNCLOS): Provides a comprehensive legal framework for the use of the seas and oceans. It defines maritime zones, rights, and responsibilities of nations, and mechanisms for dispute resolution.
2. International Maritime Organization (IMO): A specialized agency of the United Nations responsible for regulating shipping. It develops and maintains a comprehensive framework for the safety, security, and environmental performance of international shipping.
3. Marine Protection, Research, and Sanctuaries Act (MPRSA): Also known as the Ocean Dumping Act, it regulates the dumping of materials into U.S. ocean waters and promotes the protection of marine environments.
4. Convention on Biological Diversity (CBD): An international treaty with the goal of conserving biological diversity, promoting sustainable use of its components, and ensuring fair and equitable sharing of benefits arising from genetic resources.

Oceanography: Maritime Zones

Maritime zones are established under international law to define different areas of jurisdiction over ocean spaces:

1. Territorial Sea: Extends up to 12 nautical miles from the baseline. A nation has sovereignty over this area, including the airspace above and the seabed below.
2. Contiguous Zone: Extends up to 24 nautical miles from the baseline. A state can enforce laws concerning customs, immigration, and pollution.
3. Exclusive Economic Zone (EEZ): Extends up to 200 nautical miles from the baseline. A state has rights to explore, exploit, conserve, and manage natural resources, both living and non-living.
4. Continental Shelf: The extended edge of a continent submerged under shallow seas. A state has rights over the seabed and subsoil up to 200 nautical miles or beyond, depending on the geological criteria.
5. High Seas: Areas beyond national jurisdiction. They are open to all states for freedom of navigation, overflight, and the laying of submarine cables and pipelines.
6. International Seabed Authority (ISA): An organization established under UNCLOS to manage the mineral resources of the international seabed area and ensure the equitable sharing of benefits.

Oceanography: Ocean Currents and Circulation

Ocean currents are large-scale flows of seawater that move through the ocean basins. They play a crucial role in regulating the Earth’s climate by redistributing heat around the planet. There are two main types of ocean currents: surface currents and deep-water currents.

Surface Currents: These currents are primarily driven by wind and are influenced by factors such as the Earth’s rotation (Coriolis effect) and the configuration of the continents. Major surface currents include the Gulf Stream in the Atlantic Ocean, the Kuroshio Current in the Pacific Ocean, and the Antarctic Circumpolar Current.

Deep-Water Currents: Also known as thermohaline circulation, these currents are driven by differences in water density, which is affected by temperature (thermo) and salinity (haline). The global conveyor belt is a system of deep-water currents that circulate around the world, playing a key role in regulating global climate by transporting heat and nutrients.

Oceanography : Ocean  Ecosystems

The ocean is home to a vast array of ecosystems, each with unique characteristics and inhabitants. Some of the major marine ecosystems include:

1. Coral Reefs: Often referred to as the “rainforests of the sea,” coral reefs are incredibly diverse and productive ecosystems. They are built by colonies of tiny animals called coral polyps and are found in warm, shallow waters. Coral reefs provide habitat for a multitude of marine species and protect coastlines from erosion.
2. Mangroves: Mangrove forests are found in tropical and subtropical regions along coastlines. These ecosystems are characterized by salt-tolerant trees and shrubs that thrive in intertidal zones. Mangroves serve as nurseries for many marine species and act as natural barriers against storms and coastal erosion.
3. Estuaries: Estuaries are bodies of water where rivers meet the sea, creating a mix of fresh and saltwater. These environments are highly productive and provide critical habitat for many species of fish, birds, and invertebrates. Estuaries also filter pollutants from rivers before they reach the open ocean.
4. Deep-Sea: The deep-sea environment is one of the least explored and understood regions of the ocean. It includes the abyssal plains, deep-sea trenches, and hydrothermal vents. Despite the harsh conditions, the deep sea is home to a variety of unique organisms, many of which have adapted to survive in extreme environments.

Oceanography : Ocean-Atmosphere Interaction

The interaction between the ocean and the atmosphere is a critical component of the Earth’s climate system. Processes such as evaporation, precipitation, and the exchange of heat and gases play key roles in regulating weather and climate patterns. Key aspects of ocean-atmosphere interaction include:

1. Evaporation and Precipitation: The ocean is the primary source of water vapor in the atmosphere. Evaporation from the ocean’s surface contributes to the formation of clouds and precipitation. This process also plays a significant role in the Earth’s hydrological cycle.
2. Heat Exchange: The ocean absorbs and stores large amounts of solar energy, which it releases slowly over time. This heat exchange between the ocean and the atmosphere helps to moderate global temperatures and influences weather patterns.
3. Carbon Cycle: The ocean is a major component of the global carbon cycle. It absorbs a significant portion of the carbon dioxide released by human activities, helping to mitigate the impact of climate change. However, this also leads to ocean acidification, which can have detrimental effects on marine life.

Oceanography: Ocean Resources and Conservation

The ocean is a vital source of resources for human society. These resources include:

1. Mineral Resources: The ocean floor is rich in mineral resources such as oil, natural gas, and metal deposits. Extracting these resources presents both opportunities and challenges, particularly with regard to environmental impacts.
2. Renewable Energy: The ocean offers potential for renewable energy sources such as wind, wave, and tidal power. These technologies have the potential to provide sustainable energy while reducing greenhouse gas emissions.

Oceanography: Challenges and Future Directions

Oceanography faces several significant challenges in the coming years:

1. Climate Change: The impacts of climate change on the ocean are profound. Rising sea temperatures, ocean acidification, and sea level rise are just a few of the changes affecting marine ecosystems and human communities. Understanding and mitigating these impacts is a priority for oceanographers.
2. Pollution: Marine pollution, including plastic debris, chemical contaminants, and oil spills, poses a significant threat to ocean health. Efforts to reduce pollution and clean up existing pollutants are critical for the preservation of marine environments.
3. Exploration and Technology: Advancements in technology are opening new frontiers in ocean exploration. Autonomous underwater vehicles, remotely operated vehicles, and satellite-based observations are providing new insights into the ocean’s depths. Continued innovation in these technologies will enhance our ability to study and protect the ocean.

Conclusion

Oceanography is a dynamic and interdisciplinary field that provides critical insights into the Earth’s largest and least understood environment. By studying the physical, chemical, biological, and geological aspects of the ocean, scientists can better understand and manage the ocean’s resources and address the challenges posed by environmental changes. The future of oceanography will be shaped by the continued exploration of the ocean’s mysteries and the development of innovative solutions to protect and sustain this vital global resource.

Saint Rampal Ji Maharaj teaches that the entire universe was created by a Supreme God, known by various names across different religions, such as Param Akshar Purush, Param Akshar Brahm, Satpurush, Akaalmurat, Shabad Swaroopi Ram, Allah, and Rab. Saint Rampal Ji Maharaj describes Satlok as an eternal and divine realm of unparalleled beauty and tranquility. In this celestial abode, everything is radiant and pure, with landscapes of lush gardens, crystal-clear waters, and vibrant, otherworldly flora. The light in Satlok is self-luminous and soothing. Inhabitants live in perpetual bliss, free from the cycle of birth and death, experiencing divine love and harmony. 

The air is fragrant with celestial flowers, and divine music fills the realm, creating an atmosphere of profound serenity and contentment, reflecting the soul’s ultimate union with the Supreme God. According to his interpretation of sacred texts from Hinduism, Islam, Christianity, and Sikhism, this Supreme Being is the ultimate creator of all universes, gods, and living beings. Saint Rampal Ji Maharaj emphasizes that this one all-powerful God transcends all religious boundaries and is the true source of all creation, embodying the essence and unity of various religious beliefs.

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Some questions asked in upsc

1. Prelims 2023
   Consider the following statements regarding ocean currents:
   
   • Cold ocean currents originate in high latitudes and flow towards the equator.
   • The Gulf Stream is a warm ocean current in the Atlantic Ocean.
     Answer: (c) Both 1 and 2

Explanation:

• Cold currents originate from polar/high-latitude regions and flow towards the equator (e.g., Labrador Current).
• The Gulf Stream is a warm current in the Atlantic Ocean that flows from the Gulf of Mexico to Europe.

2. Prelims 2021
   Consider the following pairs:
   Sea – Bordering Country
   
   • Adriatic Sea – Albania
   • Black Sea – Croatia
   • Caspian Sea – Kazakhstan
   • Mediterranean Sea – Morocco
   • Red Sea – Syria
     Answer: (b) 1, 3, and 4 only

Explanation:

• Adriatic Sea borders Albania.
• Black Sea does NOT border Croatia; it borders countries like Turkey, Bulgaria, and Ukraine.
• Caspian Sea borders Kazakhstan.
• Mediterranean Sea borders Morocco.
• Red Sea does NOT border Syria; it borders countries like Egypt, Sudan, and Saudi Arabia.

3. Prelims 2020
   Which of the following statements about the ‘Great Atlantic Sargassum Belt’ is/are correct?
   
   • It is a dense seaweed mass spanning thousands of kilometers in the Atlantic Ocean.
   • It can cause harm to marine ecosystems and coastal economies.
     Answer: (c) Both 1 and 2

Explanation:

• The Great Atlantic Sargassum Belt is a large floating mat of brown algae spanning over 8,000 km.
• It disrupts marine ecosystems by depleting oxygen in water and affecting coastal economies by piling up on beaches.

4. Prelims 2018
   Which of the following phenomena might have contributed to the evolution of biodiversity in the world’s oceans?
   
   • Upwelling of ocean water
   • Oceanic currents
   • Submarine volcanic activity
   • Turbidity currents
     Answer: (d) 1, 2, 3, and 4

Explanation:

• Upwelling brings nutrient-rich water to the surface, supporting marine life.
• Ocean currents distribute heat, nutrients, and organisms.
• Submarine volcanic activity creates new habitats.
• Turbidity currents help redistribute sediments, shaping ocean floors.

5. Prelims 2013
   Consider the following statements regarding the El Niño phenomenon:
   
   • It is characterized by the warming of the Pacific Ocean near the equator.
   • El Niño causes weakening of trade winds.
   • It has significant effects on monsoon rainfall in India.
     Answer: (d) 1, 2, and 3

Explanation:

• El Niño is associated with warming in the central/eastern Pacific near the equator.
• It weakens trade winds, impacting global weather patterns.
• In India, it often leads to weak or deficient monsoons.

FAQ’S on Oceanography

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