Basic knowledge about geography

Content:

* Ocean vs Sea

* Sea vs Bay

* Bay vs Gulf

* Fjord

* Strait vs Channel vs Canal

* Wave vs Tide vs Current 

* Tidal Wave vs Tsunami 

*Estuary vs Delta 

*Coastal Lagoon & Atolls

* Estuary vs Lagoon 

* Meander & Oxbow Lakes

* Lake vs Pond

Ocean 

* Ocean - A continuous body of salt water that is contained in enormous basins on Earths surface.

* Ocean makes up one global, interconnected body of salt water - Water surrounding entire continents

* Deeper than the sea( On average, the depth of the Ocean is around 3,700 meters ( only 10% of the Earth's Ocean floor has been mapped)

Sea

*Sea are smaller than Oceans and usually located where the land and Ocean meet.

* Typically, seas are partially enclosed by land ( exception - Sargasso Sea) - Water surrounding smaller landmasses,

* Seas are generally much shallower than Oceans ( some seas are exceptions - Caribbean Sea is considered the deepest sea in the world, and has a depth of 7,686 meters.

Bay

* A small water body set off from a large water body, mostly where the land curves inward ( semi circular).

* It a water body surrounded by land on three sides and wide open towards the ocean/ lake towards the fourth side.

Sea vs Bay

 Sea

* Sea is a part of Ocean 

* Sea are Saline

Bay

* Bay is a part of Sea/ Ocean/Lake 

* Bay can be Saline/ freshwater 

Bay vs Gulf 

 Bay

*A bay is a board,recessed coastal inlet where the land curves inward.

* There is a Coastline on three sides of a bay, usually semi- circular.

* A bay is usually smaller and less enclosed than a bay

* The mouth of the bay, where meets the ocean or lake, is typically wider than that of a gulf.

* The Bay of Bengal is the largest bay in the world 

* Large bays were created as a result of plate tectonics.

Gulf 

*A gulf is a more defined, indented and deeper inlet with the entrance more enclosed than a bay.

* Gulfs are sometimes connected to the ocean by narrow passages of water called stairs.

* Gulfs can also have wide openings and are sometimes indistinguishable from larger bodies of water.

* The Gulf of Mexico, bordered by the United States, Mexico, and Cuba is the world's largest gulf.

Fjord 

* The fjord is a Norwegian word which translates to a " long narrow body of water"

* A fjord is a long narrow inlet characterized by steep sides or cliff, formed by glacial action.

*Fjords are found mainly in Norway, Chile,New Zealand, Canada, Greenland, and the United States. State of Alaska.

* Fjords are often set in a U- shaped valley with steep walls of rock on either side.

* Glaciers move very slowly over time and can greatly modify the landscape once they have moved through an area. This process is called Glaciation.

* Glaciation craves deep valleys

Straits 

*A strait is a narrow strip of waterway separating two landmasses and joining two large water bodies 

* Ex- Palk Strait separating India and Sri Lanka Connecting Gulf of Mannar and Bay of Bengal 

* A strait is naturally formed. Straits do not have water running in a single direction.

* Strait may or may not be navigable, depending on their depth.

It may be formed by:

* A fracture in an isthmus ( a narrow strip of land connecting two landmasses and separating two water bodies). Tectonic shifts can lead to Straits like this.

* A body of water overflowing land that has subsided or eroded. The Bosporus Strait, which links the Black Sea and the Sea of Marmara, was formed this way, Land at the southwestern edge of the Black Sea eroded and crumbled, creating a strait.

Channel 

* A channel is a wide strait or waterway between two landmasses.

* Channels can be either natural or man-made.

* Channel created by people are usually dug from the bottoms of shallow waterways so large ship's can pass through them. These are called navigation channels.

* Eg. English Channel, Ambrose Channel.

* The Ambrose Channel, which leads into New York Harbor, has been artificially deepened for large ships full of cargo.

Wave

* Undulation on the surface of a water body.

* Oscillatory surface water movements resulting in rise and fall of surface water.

* Upper part - crest,lower part- trough 

* Caused by friction between water and blowing wind.

Tide

* The regular and fall of the Ocean's waters/ sea level are known as tides. Along coasts, the water slowly rises up over the shore and then slowly falls back again.

* High tide- When the water has risen to its highest level, covering much of the shore

* Low tide- when the water falls to its lowest level.

* Some lakes and rivers can also have tides.

* The major tidal constituent is the moon's gravitational pull on the Earth, another is the rotation of Earth.

* In the open Ocean, the water bluges out toward the moon. Along the seashore, the water rises and spread onto the land.

* One bulge occurs on the side of the Earth facing the moon. This is the moon's direct tidal force pulling the ocean toward it.

* The other bulge occurs on the opposite side of the Earth - in the opposite direction of the moon. The bulge may be understood as the moon's tidal force pulling the planet ( not the ocean) towards it.

Waves vs Tide

Waves

*Definition:  Waves are the energy that moves across the surface of water.

* Cause: Wind

* Frequency: Occurs regularly across bodies of water.

Tide

* Definition:  Tides is the rise and fall of the sea level.

* Causes:  Gravitational pull from the moon and Sun

* Frequency: Occurs daily, maybe twice in a day in coastal areas.

Tidal Waves & Tsunami 

* Tidal waves, in their most basic from, are waves that follow a tide and are moved by the wind.

* Tsunami is taken from the Japanese words for " Harbor wave".

* Powerful waves that are caused by factors such as underwater earthquake, landslides or volcanic eruptions, landslides ( in which large volumes of debris fall into the water) are known as Tsunamis.

* Tsunami waves are unlike typical Ocean waves generated by wind and storms, and most tsunami do not " break" like the curling, wind- generated waves popular with surfers.

Ocean Current

* The ocean currents are the horizontal flow of a mass of water in a fairly defined direction over great distances.

* They are like river flows in oceans.

*Ocean currents are the continuous, predictable, directional movement of ocean water driven by gravity,wind ( Coriolis Effect), and water density.

* Ocean water moves in two directions: horizontally and vertically.

* Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings.

* This abiotic system is responsible for the transfer of heat, variations in biodiversity, and Earth's climate system.

Estuary 

* Shallow water zones where river meets the sea

* Partially enclosed body. Part of coastal feature 

* When freshwater and seawater combine, the water becomes brackish, or slightly salty.

* Water continually circulates into and out of an estuary. Tides create the largest flow of saltwater, while river mouths create the largest flow of freshwater.

* In estuaries, water level and salinity rise and fall with the tides.

* Built by sand bars/ Rift valley/ fjord

* Ex- Long and narrow mouth of rivers 

Delta

* The triangular or fan shaped alluvial deposit made by the rivers at their mouth.

* Deltas are formed in the regions of low tides and coastal plains.

* For a delta to form, the river must be slow and steady.

* Deltas are fertile lands.

Estuary vs Delta 

* Both are made by the rivers at their mouth of sea

* Both are in economically fertile ( either water or land)

Estuary 

* The sharp- edged mouth of rivers, devoid of any depositd

* Regions of high tides and rift valleys witness Estuaries.

* Estuary does not have fertile lands.

* Narmada and Tapi rivers from Estuaries.

Delta

* The alluvial deposits made by the rivers at their mouth 

* Deltas are formed in the regions of low tides and coastal plains.

* Deltas are fertile lands.

* Ganga and Brahmaputra, Krishna, Kaveri and Mahanadi from delta.

Lagoon

* Lagoon - semi- enclosed waters, relatively isolated from open sea

* A lagoon is a shallow body of water that may have an opening to a larger body of water, but is also protected from it by a sandbar or coral reef

* Ex- Cillika Lake in Odisha, Pulicat Lake in Andhra Pradesh 

* Lagoon are commonly divided into coastal lagoons ( or barrier lagoons) and atoll lagoons.

Atoll lagoon

* Atoll - ring - shaped coral island, or series of islets. The atoll surrounds a body of water called a lagoon.

* Atoll lagoons are similar to coastal lagoons. Instead of being sheltered by sandbars or barrier islands, atoll lagoons are protected by coral reefs.

* Atoll lagoons are very common in the tropical waters of the South Pacific and Indian Oceans.

*Atoll lagoons from as coral reefs from around volcanic islands. Over millions of years, the island subsides into the ocean. The ring of coral reefs, however, remain. The reefs become the atoll, protecting an enclosed lagoon where the volcano used to be.

* Coral reefs and coral sand are made of limestone, the remains of billions of tiny coral exoskeletons. As limestone leaches into the lagoon, it turns the water bright blue.

Estuary vs Lagoon 

Estuary 

* Coastal features 

* Shallow water 

* Fresh & Saline water mixing 

* It can be river mouth, bars & fjords.

* No Corals.

Lagoon 

*Coast features 

* Shallow water 

* No mixing or relatively less fresh water.

* It can be because of Bars, Corals, Tectonics.

* Have large biodiversity 

* If it is coral lagoon it is like rain- forest of Ocean.

Meander 

* Meander - bending in course of a river.

* It is a result of erosion & deposition.

*It is produced as a watercourse erodes the sediments of an outer ( concave) bank and deposits sediments on an inner ( convex) bank

* Common in mature and old stages of erosion where lateral erosion is prominent and stream gradient is gentle.

* In the last stage of river, meanders become very prominent.

Oxbow Lakes 

* Ox- bow- lake - an ox- bow lake is a U shaped lake or pool that froms when a wide meander of a river is cut off, creating a free standing body of water 

Lakes vs Ponds

Ponds

* Ponds are shallow bodies of still water

* Sunlight reaches the bottom allowing plants to grow.

* Plants, bacteria and algae share the ecosystem with small animals.

Lake

* Lakes are deeper bodies of still water.

* Sunlight does not reach the bottom and lakes are colder than ponds

* Larger fish and organisms can survive in lakes. Bacteria and algae are also present.