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Semester 3: Core Course OCEANOGRAPHY
Oceanography Definition, - Extent and Distribution Surface Configuration of the Ocean floor, Hypsometric Curve Continental Shelf Continental Slope Abyssal Plain Deeps and Trenches
Oceanography
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Oceanography is the scientific study of the ocean, encompassing its physical, chemical, biological, and geological aspects.
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The oceans cover approximately 71% of the Earth's surface, divided into five main oceans: the Pacific, Atlantic, Indian, Southern, and Arctic Oceans.
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The ocean floor features various landforms such as continental shelves, slopes, abyssal plains, oceanic deeps, and trenches.
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The hypsometric curve illustrates the distribution of land and oceanic elevations, showing that most ocean areas are at depths below sea level.
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The continental shelf is a shallow sea area extending from the coastline to the shelf break, rich in marine life and resources.
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The continental slope is the steep descent between the continental shelf and the deep ocean floor, marked by subduction zones and erosion.
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Abyssal plains are flat or gently sloping areas of the deep sea floor, typically found at depths between 3,000 and 6,000 meters.
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Oceanic deeps and trenches are the deepest parts of the ocean, formed by tectonic activity, and are characterized by extreme pressure and cold temperatures.
Bottom Relief of the Pacific, Atlantic and Indian Oceans, Sea water Composition of Sea water
Bottom Relief of the Pacific Ocean
The Pacific Ocean, the largest and deepest ocean, features significant underwater relief. Key features include the Mariana Trench, which is the deepest part of the world's oceans, and various seamounts and ridges. The ocean floor consists of continental shelves, slopes, abyssal plains, and mid-ocean ridges. The complex geology is shaped by tectonic activity, leading to phenomena such as subduction zones and volcanic islands.
Bottom Relief of the Atlantic Ocean
The Atlantic Ocean has a distinct bottom relief characterized by the Mid-Atlantic Ridge, which is a divergent tectonic plate boundary creating new oceanic crust. Other features include the Caribbean Sea and various underwater mountains and trenches. The continental shelf is significantly wider than in the Pacific, and the ocean is home to both abyssal plains and numerous seamounts.
Bottom Relief of the Indian Ocean
The Indian Ocean, smaller and less studied than the Pacific and Atlantic, features unique bottom relief such as the Ninetynine East Ridge and the Sunda Trench. It also contains several mid-ocean ridges and deep-sea trenches. The bathymetry influences ocean currents and marine biodiversity.
Composition of Sea Water
Sea water consists of approximately 96.5% water and 3.5% dissolved salts, primarily sodium chloride. Other components include magnesium, sulfate, calcium, potassium, and trace elements. The composition can vary with location and depth, influenced by factors such as evaporation, river inflow, and biological activity. Temperature and pressure also affect the solubility of gases like oxygen and carbon dioxide.
Importance of Understanding Ocean Relief and Sea Water Composition
Studying ocean relief and water composition is essential for understanding marine ecosystems, climate regulation, and ocean circulation. Knowledge of underwater landscapes aids in navigation, resource management, and environmental protection.
Ocean Temperature and Salinity Distribution and Factors Horizontal and Vertical - Factors Affecting Temperature and Salinity Distribution
Ocean Temperature and Salinity Distribution
Overview of Ocean Temperature
Ocean temperature varies with depth and geographic location. Surface temperatures are influenced by solar radiation, while deeper waters remain colder due to the absorption of heat in the upper layers.
Overview of Salinity
Salinity refers to the concentration of dissolved salts in seawater. It can significantly affect water density and is influenced by evaporation, precipitation, river runoff, and ice melting.
Horizontal Distribution of Temperature
Horizontal distribution of ocean temperature is affected by ocean currents, wind patterns, and geographic features. Warm equatorial waters mix with cooler polar waters, creating temperature gradients.
Horizontal Distribution of Salinity
Salinity distribution horizontally is influenced by river inflow, evaporation rates, and ice formation/melting. Coastal regions may have varying salinity levels due to freshwater input.
Vertical Distribution of Temperature
Temperature decreases with depth due to lack of sunlight. This creates thermoclines, which are layers within the ocean where the temperature changes rapidly with depth.
Vertical Distribution of Salinity
Salinity can also change with depth, often increasing as depth increases due to the compaction of water molecules and the influence of water density.
Factors Affecting Temperature
Factors include solar radiation, atmospheric conditions, ocean currents, and geographical features. Tropical regions receive more direct sunlight, while polar regions receive less.
Factors Affecting Salinity
Salinity is influenced by evaporation, precipitation, ice melting, and freshwater inputs from rivers. High evaporation rates lead to increased salinity, while heavy rainfall decreases it.
Ocean Water Movement Waves Tides Types - Ocean Currents Types - Currents of Pacific, Atlantic and Indian Oceans
Ocean Water Movement
Waves
Waves are surface phenomena caused by the wind blowing across the ocean. Their height and energy depend on wind speed, duration, and fetch. Key types include capillary waves, wind waves, and swells.
Tides
Tides are the periodic rise and fall of sea levels caused by the gravitational forces exerted by the moon and the sun. They are typically semi-diurnal or diurnal in nature, with two high and two low tides occurring daily.
Types of Ocean Currents
Ocean currents are large-scale water movements driven by factors like wind, salinity, temperature differences, and the Earth's rotation. They can be classified into surface currents and deep-water currents.
Currents of the Pacific Ocean
Major currents include the Kuroshio Current, California Current, and the North Equatorial Current. These currents play a significant role in regulating climate and marine biodiversity.
Currents of the Atlantic Ocean
Key currents include the Gulf Stream, North Atlantic Drift, and Canary Current. The Gulf Stream, in particular, significantly influences the climate of eastern North America and Western Europe.
Currents of the Indian Ocean
Prominent currents include the Agulhas Current, Somali Current, and the Equatorial Counter Current. These currents are influenced by monsoonal winds and significantly affect local weather patterns.
Ocean Deposits Types - Coral Reefs Formation and types - Ocean Resources and Need for Conservation - National Institute of Ocean Technology NIOT
Ocean Deposits Types
Coral Reefs
Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. They are found in shallow, warm waters and require sunlight to thrive. Coral reefs provide habitat for many marine organisms.
Formation of Coral Reefs
Coral reefs form mainly through the growth of corals from small polyps that secrete calcium carbonate. The process involves several stages: the initial colonization of the ocean floor by coral larvae, growth of the coral, and accumulation of dead coral, which contributes to the reef structure.
Types of Coral Reefs
There are three main types of coral reefs: fringing reefs, barrier reefs, and atolls. Fringing reefs are directly attached to the shore. Barrier reefs are separated from land by a lagoon. Atolls are ring-shaped reefs that encircle a lagoon.
Ocean Resources
Ocean resources include living resources like fish, mollusks, and seaweed, as well as non-living resources such as minerals, oil, and natural gas. These resources are crucial for human survival and economic development.
Need for Conservation
Conservation of ocean resources is vital due to threats like climate change, pollution, and overfishing. Sustainable practices and policies are necessary to protect marine biodiversity and ensure the health of ocean ecosystems.
National Institute of Ocean Technology (NIOT)
NIOT is an organization in India focused on developing technologies for sustainable use and conservation of ocean resources. Its initiatives include research on ocean energy and technologies for resource management.
