The Hydrosphere.
- OCEANS OF THE WORLD-FEATURES.
The World Ocean or Global Ocean (colloquially the sea or the ocean) is the interconnected system of Earth’s oceanic waters, and comprises the bulk of the hydrosphere, covering 361,132,000 square kilometres or 139,434,000 square miles (70.8%) of Earth’s surface, with a total volume of roughly 1,332,000,000 cubic kilometres (320,000,000 cubic miles). Ocean constitute more than 79% of earth surface .the ratio of continential land mass is higher in the Northern hemisphere comparison to southern hemisphere.
Distribution of water on the earth surface is extremely uneven. only 3% of water on the surface is fresh ;the remaining 97% Ri sides in the ocean. of the freshwater, 69% resides in the the glaciers ,30% underground, and less than 1% is present in lakes, rivers ,and swamps. Look at another way only 1% of freshwater on the earth surface is usable by humans, and 99% of the usable quantity Is not accessible.
🔸️ how is freshwater different from saline water? Vinayiasacademy.com Saltwater is denser than fresh water because of its salt content. When it rains the freshwater reduces the saltiness of the saltwater on the surface. Saltwater is made when freshwater moves over land. Saline water contains high amount of salt. fresh water contain dissolved salt in concentration Less than 0.5 % .thus,salinity ,or density of salt , is much higher in saline water, thogh freshwater is not completely devoid of salts. brackish water is a mixture of salt and freshwater. - 2.SALINITY OF THE OCEANS.
Almost every known element is present in the ocean is varied proportion ;the highest proportion dissolved mineral in that of NaCl ,which constitutes nearly 77% of all minerals.There are many chemicals in seawater that make it salty. Most of them get there from rivers carrying chemicals dissolved out of rock and soil. The main one is sodium chloride, often just called salt. Most seawater has about 35 g (7 teaspoons) of salt in every 1,000 g (about a litre) of water. This doesn’t sound very much, but it would take close to two 6 m shipping containers full of salt to make an Olympic-size swimming pool as salty as the sea. Free flow and interconnectivity of ocean water ensures uniformity in the proportion of various salts in the ocean around the world .the average salinity of ocean water is 35 part of salt per 1000 part of ocean water.however , in the case of landlocked seas ,the salinity level is high. salinity of Dead Sea is 250 part of salt per 1000 part of water.
The warm water dissolves higher amount of salt in comparison to cold water.thus, ocean water is equatorial regions, in comparison to polar regions, have higher concentration of salt. also surface ocean water ,in comparison to deep ocean water, have higher concentration of salt. Vinayiasacademy.com
3.OCEAN RELIEF.
The Oceanic relief features are in the form of mountains, basins, plateaus, ridges, canyons and trenches beneath the ocean water. These forms are called Submarine Relief.
🔸️Continental shelf:A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water known as a shelf sea. Much of these shelves has been exposed during glacial periods and interglacial periods. It Is an area of seabed around a large land mass where the sea is relatively Shallow compared to the open ocean. the continental shelf geological part of the continental crust. it may also be regarded as a part of the continent submerged due to rise in the sea level. Continental shelves are the richest fishing ground due to the abundance of palnkton in these regions . Vinayiasacademy.com
🔸️Continental slope:
The continental slope is commonly dissected by submarine canyons; faulting, rifting and slumping of large blocks of sediment can form steep escarpments, relatively flat terraces and (under certain conditions) basins perched on the slope. Beyond the continental shelf, there is an abrupt change in the continental land leading to the formation of Continental slope..
🔸️ Ocean plain: it is the floor of the ocean and comprises two -third of the oceans.
🔸️ocean deep or trenches:
Ocean trenches are steep depressions in the deepest parts of the ocean . These are long ,narrow trenches that go up to great depths.
4.TEMPERATURE OF OCEAN WATER.
🔸️The temperature of the oceanic water is important for marine organisms including plants and animals. The temperature of sea water also affects the climate of coastal lands and plants and animals therein. Temperature of the oceans drops as we go from the equator towards the poles. the annual range of temperature in oceans is narrow compared to that on land within a particular area and is less than 10 degree Celsius for most of the ocean area. the temperature of ocean also varies vertically with depth. on the surface of oceans ,temperature is maximum due to direct exposure to sunrays.the temperature drops vertically till 12,000 feet. beyond 12,000 feet, temperature is uniformly cold, just a little about the freezing point. - OCEAN CURRENTS.
Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind 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. Vinayiasacademy.com
Ocean currents are continuous movement of ocean water in a particular pattern.. ocean currents are of two types:
1.warm current:
Warm ocean currents flow away from the equatorial region on the western side of ocean basins. They are called so because these currents carry water from the equator towards high latitude. - Cold current:
Cold currents flow toward the equator on the eastern side of ocean basins. They are called so because these currents carry cold water from the poles towards lower latitudes. Examples of cold ocean currents include the Canary Current in the North Atlantic, the California Current in the North Pacific, and the Benguela Current in the south Atlantic.
🔸️ factors influencing ocean currents:
⏺winds:Wind is the flow of gases on a large scale. energy of winds power the circulation of ocean water.
⏺temperature of water:
The temperature of tap water is dependent on the temperature of the pipes, which is dependent on both the temperature of the house and the outdoor environment. Warm water flows and the surface and cold water sinks to the bottom.
⏺salinity of water:
Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water. water with higher salinity floors at the bottom, and water with lesser salinity flows at the surface .
⏺earth’s rotation:
Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water. rotation of earth generates the coriolis force, which deflects the ocean water. ocean water,like winds, is deflected to the right side in the Northern hemisphere and to the left side in the southern hemisphere.
⏺landmass: Landmass is a contiguous region of land surrounded by ocean.which Diverts and obstructs ocean currents.
🔸️ North Indian ocean current:
The North Indian ocean current arises on account of monsoon winds.this current experience seasonal reversal .there is a complete reversal in the direction of ocean current with the change in season.monsoon winds in Northern Indian ocean are peculiar to the region, which directly influence the ocean surface water movement . While during summer ,south- West Monsoon drag the ocean water. Thus,the ocean current flows in the south- west direction .consequently ,during summers ,the North Indian ocean current is called Southwest monsoon drift. During winters,the North -east monsoon drags the ocean water.thus, the ocean current flows in the north- east direction and is called the the North-east monsoon drift.
🔸️ effects of ocean current:
Ocean currents act much like a conveyor belt, transporting warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. Thus, ocean currents regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth’s surface. Without currents in the ocean, regional temperatures would be more extreme—super hot at the equator and frigid toward the poles—and much less of Earth’s land would be habitable.
⏺ climate at the West Coast of Landmasses:
The West Coast continents and tropical and subtropical latitude are bordered by cold waters .the average temperature are relatively low with a narrow diurnal and annual range. On the other hand the West Coast of the continents in the middle and high latitude are bordered by warm water cold water lead to descending winds and coastal areas adjoining them do not require rainfall the North Atlantic just ensure the pots in higher latitudes remain functional throughout the year as the narvik what remains functioning throughout the year despite its location at a very high latitude.
⏺ climate at the east coast of landmasses:
Warm current flow parallel to the cost of the continents in the tropical and subtropical latitudes. On the other hand, cold current flow parallel to the east of continents in the middle and higher latitudes .consequently, these regions experience less rainfall. Warm current cause wind to get warmer and rise .these rising wind undergo condensation and cause rainfall.
⏺effect on biodiversity:
These ecological effects of biodiversity in turn are affected by both climate change through enhanced greenhouse gases, aerosols and loss of land cover, and biological diversity, causing a rapid loss of biodiversity and extinctions of species and local populations. The mixing of warm and cold currents helps in replenish the oxygen and favour the growth of biodiversity. Meeting the currents provide favourable and susceptible conditions for the breeding of marine organism. The best fishing Grounds of the world exist mainly in these mixing zones .
6.WAVES.
Waves are a disturbance on the surface of the sea or ocean, in the form of a moving ridge or swell.Waves are caused by the transfer of energy from the wind to the sea (not to be confused with tides which are caused by the Moon). As the wind blows over the surface of the sea, it creates friction forming waves. In deep water, water molecules within a wave move in a circular movement. It is only in shallow water that the water itself is moving forward, which occurs along the coastline where the land meets the sea. Wind causes waves to travel in the ocean . Energy in the Waves reduces on account of friction experienced due to Continental shelves. The remaining energy, after passing over the continental shelves is released by the waves on shore lines.
7.TIDES.
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth. Tide tables can be used for any given locale to find the predicted times and amplitude. Visa cost on account of gravitational pull, mainly of the Moon. Gravitational force of the Moon causes the oceans to bulg in the direction of the Moon . As the earth undergoing rotation, two Tides occur each day, namely high tide and low tide.
tides are also of the following two types:
⏺ spring tide :
A spring tide is a common historical term that has nothing to do with the season of spring. Rather, the term is derived from the concept of the tide “springing forth.” … these are strong Tides because this tides occur when the earth, sun ,and moon are in the same line .the gravitational pull of both the moon and the sun contributes To tides. spring tide occur at full moon or new moon .
⏺ neap tide:
A neap tide—seven days after a spring tide—refers to a period of moderate tides when the sun and moon are at right angles to each other. These are weak tides.these tides occur when the gravitational forces of the moon and sun are perpendicular to each other.these tides occurs during quarter moons .
8.TSUNAMI.
tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions above or below water all have the potential to generate a tsunami. Tsunami are huge waves generated by tremors in Ocean waters .Tsunami would occur only if the the epicenter of the tremors is Below Oceanic water and the magnitude sufficiently high other causes of Tsunami can be the following:
⏺ landslides on the sea floor.
⏺ large volcanic eruptions.
⏺ meteorite impact in the ocean.
⏺ explosion.
