Oceanography

Answer : Salinity refers to the total quantity (or concentration) of dissolved inorganic solids in water. It is defined as total amount of solid material in grams contained in one kilogram of sea water and is expressed as part per thousand (1‰).

The oceanic salinity not only affects the marine organisms and plant community but it also affects the physical properties of ocean water like temperature, density, currents etc. More saline water freezes slowly while less saline water ....

Answer : Pelagic deposits consist of matter derived from algae and are mostly in the from of liquid mud. Pelagic deposits are oozes generally divided into two groups based on lime and silica content.

1. Calcareous ooze
2. Silicious ooze

In Calcareous ooze, lime content is in abundance. Therefore, it is highly soluble. Because of high solubility it is seldom found at greater depths.

Also, on the basis of principal organisms, ....

Answer : current status of coral reefs

• Estimates in this report are that 20% of the world’s coral reefs have been effectively destroyed and show no immediate prospects of recovery;
• Approximately 40% of the 16% of the world’s reefs that were seriously damaged in 1998 are either recovering well or have recovered;
• The report predicts that 24% of the world’s reefs are under imminent risk of collapse through human pressures; and a further 26% are under a longer ....

Answer : Origin of Sargasso Sea and lagoon

The Sargasso Sea is a vast patch of ocean named after a genus of free-floating seaweed called Sargassum. While there are many different types of algae found floating in the ocean all around the world, the Sargasso Sea is unique in that it harbors species of Sargassum that are ‘holopelagic’ - this means that the algae not only freely floats around the ocean, but it reproduces vegetatively on the high ....

• A storm surge is an offshore rise of water associated with a low pressure weather system, typically tropical cyclones and strong extratropical cyclones. Storm surges are caused primarily by high winds pushing on the ocean’s surface. The wind causes the water to pile up higher than the ordinary sea level. Low pressure at the center of a weather system also has a small secondary effect. It is this combined effect of low pressure and persistent wind over a shallow water ....

Answer : Coral reefs and atoll have their own significance in the ocean. These are created by piling up of coral polyps. Coral reefs are formed between 25N to 25S latitude along with island and coast or sea mounts at appropriate depth. Coral reefs are always found below sea level as corals cannot survive outside water. Conditions of their formation are following :

• Corals are mainly found in tropical sea region because high temperature is required for survival
• They ....

Answer : Ocean water is layered from ocean basin to surface. This layering is because of difference in density, salinity, temperature. There are three layers on the basis of density:

1. Layer with minimum density - the first layer spreads from 100 to 200 m deep. It is also known as Photic zone. It has 2% of total ocean volume. This layer has density variation according to weather and region.
2. Layers with sharp density gradient (Pycnocline) - this middle layer ....

Answer : Indian Ocean is smaller than the Pacific and the Atlantic Ocean and is bounded on all of its sides i.e. Asia in the north, Africa in the west, Australia in the south east and Antarctica in the south. There is wide range of variation in the continental shelves of the Indian Ocean. Quite extensive selves are found along the eastern coast of Africa, Medagaskar. Along the margins of Arabian sea and Bay of Bengal. On ....

Answer : The Sun is the ultimate source of energy on the earth. The oceans are heated through the process of convection, conduction and radiation. The heat budget of the oceans is the Sum of total incoming energy to the oceans and its expenditure through the various process of heat related activities. In general the heat budget of the ocean is balanced one i.e. supply of energy is equal to losses of energy.

The heat budget of ocean ....

Answer : The Seafloor spreading theory was propounded by Prof. Harry Hess and Robert S. Dietz in 1960. It states that oceanic crust is continuously being renewed resulting in the spreading of ocean in the mid oceanic regions.

Hess postulated that along the mid oceanic regions there are certain elevated hill like features known as mid oceanic ridges, which are situated on the rising thermal convection currents originating from the mantle. The hot magma from the Aesthenosphere continuously ....

Answer : Coral reefs and atolls are significant submarine features. These are formed due to accumulation and compaction of skeletons of lime secreting organisms known as coral polyps. They are also called ‘the rainforests of the oceans’.

Conditions required for the growth of the corals:

• Corals are found mainly in the tropical oceans and seas because they require high mean annual temperature for their survival.
• Corals do not live in deeper water that is not more than 200 to 250 ....

Answer : The oceanic sub-system of earth is more diverse and complex than land sub-system. The occurrence and availability of deposits over ocean floor proves this beyond doubt. All the materials that accumulate on the ocean floor is known as Ocean deposits. The first method to classify the oceanic deposits on the basis of their origin was proposed by Sir John Murray and A.F. Renard in 1891. This classification proved to be very useful in understanding about ....

Answer : Ocean currents of Northern Atlantic are as follows:

A. North Atlantic Ocean Warm Currents

1. North Equatorial Current : Normally, the north equatorial current is formed between the equator and 10°N latitude. This current is generated because of upwelling of cold water near the west coast of Africa. On the average the north equatorial warm current flows from east to west. This current, after being obstructed by the land barrier of the east coast of Brazil is bifurcated ....

Answer : It is in the recent past that ocean have become an important focus of study. The study of the bottom relief of the ocean bodies have thrown considerable light in understanding the major geological processes and phenomena which helped in the evolution of the revolutionary theory of Plate Tectonics.

The surface beneath the water is characterised by a great diversity of relief features and the Indian Ocean is no exception to it. Indian Ocean is the ....

Answer : The Atlantic Ocean located between North and South Americas in the West and Europe and Africa in the east, is the most widely studied ocean. It covers an area of 82 million square kilometer, which is about 1/6 th of the total area of the world. The shape of the ocean is very striking in the form of letter ”S” which Indicates, according to the theory of Plate Tectonics, that the contenents on either side ....

Answer : The wealth of sea is large. The sea is the store house of various important resources - biotic, mineral and energy resources. All the resources are not being utilised since we have limited expertise to utilise them on a cost-effective basis.

• The biotic resources contained in the sea are gigantic in proportion. Of these humans consume numerous varieties of fish, crustaceans, sea weeds, molluscs and other edible forms of marine life. Fish is the most important ....

Answer : The study of the ocean floor topography has thrown valuable light in understanding the various geological processes and past geological events that have led to the formation of earth's crust and other associated features.

The surface beneath the ocean water is characterised by a great diversity of relief features, i.e. towering mountain chains, deep canyons, flat plains, trenches etc. Ocean floor topo­graphy has been classified following categories:

(1)Continental Shelves: The shallow submerged extension of continent is called ....