Global environmental segments and its structures

Central University of Kerala

W E L C O M E


Global Environmental Segments and its Structures

Ms. Ashi la Babu. PI Semester , Masters Dept. Envi ronmenta l Sc iencesCentra l Univers i ty of Kera la


INTRODUCTION

Uniqueness of mother Earth, what we believe created life on it and those with which life is

sustained and protected has always dragged attention of environmentalists. Being so advanced,

as we all believe, fictions rules over facts when it comes to sciences that explore both depths as well

as the open space above.

Here we’ve a brief note on basic known facts on Environmental Segments & Structures


THE ENVIRONMENTAL SEGMENTS

Atmosphere

Hydrosphere

Lithosphere

Biosphere


ATMOSPHERE

The atmosphere is a layer of gases which surrounds the entire

Earth.


C o m p o n e n t s o f A t m o s p h e r e


Layers of the Atmosphere


TroposphereThe troposphere is the lowest layer of Earth's atmosphere.

The troposphere starts at Earth's surface and goes up to a height of 7 to 20 km (4 to 12 miles); bounded from stratosphere by Tropopause.

Most of the mass (about 75-80%) of the atmosphere is in the troposphere.

Almost all weather occurs within this layer.Air is warmest at the bottom of the troposphere near ground level. Higher up it gets colder.

Air pressure and the density of the air are also less at high altitudes.

The troposphere is heated from below. Sunlight warms the ground or ocean, which in turn radiates the heat into the air right above it.

Most clouds are found in the troposphere.


STRATOSPHEREThe stratosphere is the second layer (going upward) of Earth's atmosphere; bounded above by stratopause.

Boundaries : Lower - Near the equator - aroud16km(10miles) Near the mid latitudes- around

10km(6miles) Near the pole- around 8km(5miles)

Upper - 50km(31 miles)

Features : Forms about 20-25% of total atmospheric mass Ozone layer situates in this layer

Commercial jet aircraft fly in the lower stratosphere to avoid the turbulence which is common in the troposphere below.

Air is roughly a thousand times thinner at the top of the stratosphere than it is at sea level. Because of this, jet aircraft and weather balloons reach their maximum operational altitudes within the stratosphere.


MesosphereMesosphere (In Greek, “meso” means “middle”)

The mesosphere is the third layer (going upward) of Earth's atmosphere; bounded above by mesopause.

This layer ranges between 45 to 92 kmForms less than 1% of the total massSharp decline in temperature -93°C (-137°F) at top

Boundaries : Lower -The mesosphere starts at 50 km (31 miles) above Earth's

Upper -The mesosphere goes up to 85 km (53 miles) highAs you get higher up in the mesosphere, the temperature gets colder. The top of the mesosphere is the coldest part of Earth's atmosphere.

[ -90°C (-130° F)]!Most meteors from space burn up in this layer.


About mesosphere….!

Scientists know less about the mesosphere than about other layers of atmosphere. The mesosphere is hard to study. Weather balloons and jet planes cannot fly high enough to reach the mesosphere. The orbits of satellites are above the mesosphere. But we do get some measurements using sounding rockets which makes a short flights.


ThermosphereThermosphere (from the Greek “therme” meaning heat)

The Thermosphere is the fourth layer (going upward) of Earth's atmosphere; bounded above by thermopause.It extends from about 90 km (56 miles) to between 500 and 1,000 km (311 to 621 miles) above our planet.

Temperature :Lower thermosphere (below 200 to 300 km altitude)-about 200° C (360° F), hotter in the daytime than at night; and roughly 500° C (900° F) hotter when the Sun is very active than at other times.Upper thermosphere: can range from about 500° C (932° F) to 2,000° C (3,632° F) or higher.


The space shuttle and the International Space Station both orbit Earth within the thermosphere!

Much of the X-ray and UV radiation from the Sun is absorbed in the thermosphere.

The aurora (the Southern and Northern Lights) primarily occur in the thermosphere.

About thermosphere….!


The Exosphere

Very high up, the Earth's atmosphere becomes very thin. The region where atoms and molecules escape into space is referred to as the exosphere. The exosphere is on top of the thermosphere.


Other Layers of Atmosphere

Ionosphere : Scientists call the ionosphere an extension of the thermosphere.

High-energy solar photons tear electrons away from gas particles in the thermosphere, creating electrically-charged ions of atoms and molecules which creates the ionosphere.

Ionosphere is broken down into the D, E and F regions. The breakdown is based on

what wavelength of solar radiation is absorbed in that region most frequently.


The D region is the lowest in altitude, though it absorbs the most energetic radiation, hard x-rays. The D region doesn't have a definite starting and stopping point, but includes the ionization that occurs below about 90km.

The E region peaks at about 105km. It absorbs soft x-rays.

The F region starts around 105km and has a maximum around 600km. It is the highest of all of the regions. Extreme ultra-violet radiation (EUV) is absorbed there.



On a more practical note, the D and E regions reflect AM radio waves back to Earth. Radio waves with shorter lengths are reflected by the F region. Visible light, television and FM wavelengths are all too short to be reflected by the ionosphere. So your TV stations are made possible by satellite transmissions.


Ozonosphere : The ozone layer is a range of altitudes in Earth's stratosphere which has a

higher concentration of ozone molecules. Ozone is an unusual type of oxygen

molecule. It is created when high-energy ultraviolet light from the sun, strikes a normal oxygen molecule.

The ozone layer extends from roughly 15 to 35 km (9 to 22 miles) above sea level. The peak of ozone concentration is between 20 and 25 km(12 and 16 miles).


Also…

Ozone layer protects us from UV radiation in sunlight and acts like a sunscreen for planet Earth. The ozone layer stops almost all of the incoming UV-C, about 90% of the UV-B, and roughly half of the UV-A radiation.

The ozone molecules which absorb UV radiation later re-radiate the energy as heat, warming the stratosphere.


Ozone Depletion

Various chemicals that human release into the atmosphere can destroy ozone in the stratosphere.

In the 1980s, scientists noticed that the ozone layer was thinning.

They also noticed huge holes in the ozone layer, especially over Antarctica.

They convinced people and governments around the world to reduce emissions of ozone-destroying chemicals. They hope the ozone layer will heal itself over time.


Homosphere (“homo” means “same”)

Well-mixed gases from 0-80 km.

Heterosphere (“hetero” means “different”)

Settling of gases according to weight above 80 km.


Layers of the Atmosphere


LITHOSPHERE

The outer part of the Earth, consisting of the crust and the upper mantle. It is about 55 km (34 mi) thick beneath the oceans and up to about 200 km (124 mi) thick beneath the continents. The high velocity with which seismic waves propagate through the lithosphere suggests that it is completely solid, when comparing with asthenosphere, atmosphere, hydrosphere.


CORE

The core is a layer rich in iron and nickel found in the interior of the Earth. It is composed of two sub-layers: the inner core and outer core. The core is about 7,000 kilometers in diameter. The Earth's core is solid mass of iron plus some nickel surrounded by a fluid (water-like) outer layer. The closer you get to the core, the hotter it becomes and the greater the pressure.Other factors affect the gravity field too..


Inner Core : Inner region of the Earth's core. It is thought to be solid iron and nickel with a density of about 13 grams per cubic centimeter. It also has a diameter of about 1220 kilometers. Also known as siderosphere.

Outer Core : Outer region of the Earth's core. It is believed to be liquid nickel and iron and has a density of about 11 grams per cubic centimeter. It surrounds the inner core and has an average thickness of about 2,250 kilometers.


Crust

Earth's outer most layer of solid rock. Between 7 to 70 kilometers thick.

Two types of crust exist:

Oceanic crust and Continental crust.


Oceanic Crust : Basaltic portion of the Earth's crust that makes up the ocean basins. Approximately 5 to 10 kilometers thick.

Sima Layer : The part of the crust that forms the ocean basins and lower layers in the crust and is composed of relatively heavy, basaltic rocks.

Continental Crust : Granitic portion of the Earth's crust that makes up the continents. Thickness of the continental crust varies between 20 to 75 kilometers.

Sial Layer : The part of the crust that forms the continents and is composed of relatively light, granitic rocks.


Mantle

Layer of the Earth's interior, composed of mostly solid rock that extends from the base of crust to a depth of about 2,900 kilometers.


Hydrosphere

The Hydrosphere is the total water presence on the earth, so encompassing that found in the largest oceans and the smallest ponds, in the soil and that contained in the air. Along with the atmosphere, the biosphere and the geosphere.


Oceans-96.5% of water found here

Fresh water-3.5% water found hereIce -1.762%(Ice bergs, Glaciers, Snow..)Ground water-1.7%Surface fresh water-0.014%Atmosphere & soil-0.002%

Distribution


FRESH WATER LOCATIONSSURFACE WATER

What is the difference between watershed and river basin?

River basin: The term used to describe an area that drains into a large river

Watershed: The term used to describe an area that drains into smaller river or stream.

Larger river basins are made up of many inter connected watersheds.

The water in a watershed runs to the lowest point- river, stream or ocean.

E.g. : River Ganga & Brahmaputra are made up of many small watersheds.


River : A large channel along which water is continually flowing down a slope made

of many stream that comes together. Stream : A small channel along which water

is continually flowing down a slope made of small gullies.

Lake : A body of water of considerable size contained on a body of land.

Ground water : the water found in the cracks and pores in sands, gravels and rocks below the earth’s surface.

Aquifer : a porous rock layer underground that is a reservoir


OTHER SURFACE WATER

Wetland : An area where the water the water table is at, near or above the land surface long enough during the year to support plant growth.

Types: swamps, bogs and marshes.Swamps- a wet land dominated by trees

Bogs-a wet land dominated by peat moss Marshes- a wet land dominated by grass.

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Biosphere

The biosphere is the outermost part of the planet's shell, including air, land, surface rocks, and water within which life occurs, and which biotic processes in turn alter or transform. From the broadest bio-physiological point of view, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere(All the nonliving things that make up the earth(dirt, rock, etc.), hydrosphere (The Oceans, river, etc.), and atmosphere (Air and its "relatives", hydrogen, Co2, etc.). This biosphere is postulated to have evolved, beginning through a process of biogenesis or biopoesis, at least some 3.5 billion years ago.


Contd..

The parts of the land, sea, and atmosphere in which organisms are able to live. The biosphere is an irregularly shaped, relatively thin zone in which life is concentrated on or near the Earth's surface and throughout its waters.


The Biosphere is organized in a hierarchical structure in which individual organisms are organized into Populations.

Several interacting populations form Biotic Communities.

And a distinctive community living in a certain physical environment forms an Ecosystem.

An ecosystem is a group of animals, plants, and microbes interacting with each other and with their physical environment in such a way as to ensure their existence.

Biosphere and the Ecosystem


Hence an ecosystem is the functional unit of sustainable life on Earth.

No individual cell, population, or biotic community forms a sufficient entity to support life.

In general, ecosystems do not have sharp boundaries. Instead there are gradational or transitional communities referred to as Ecotones.

Several related or similar groups of ecosystems are known as Biomes.

Biomes are grouped into two distinct categories: Terrestrial Aquatic

Cont..


Terrestrial biomes: Consist of ecosystems inhabiting land environments such as tundra, temperate grasslands, tropical forests or hot deserts; whereas aquatic biomes consist of water-dwelling ecosystems such as pelagic, and benthic freshwater ecosystems.

Aquatic biomes:They are typically distinguished by salinity, climate, and water depth.

Biomes


Common Ecosystem Functions

Despite the variations among ecosystems, they all share a common structure due to common functions of basic processes within each ecosystem.

They all engage in energy transfer within the community , and energy in an ecosystem flows in one direction.

They all must recycle various chemical substances required for growth, reproduction, and protection.


Contd..

As a result, the basic biotic structure is based on feeding relationships. The producers, consumers, and detritus feeders and decomposers are the basic feeding categories that allow energy and matter to flow through ecosystems. All organisms must feed to satisfy the basic processes listed above.


Abiotic factors in an Ecosystem

In addition to biological factors such as the food web, there are physical and chemical factors that determine the survival of an organism in an ecosystem, and can also affect structure of the ecosystem.

The abiotic (non-biological) factors in an aquatic environment would include salinity, temperature, light, chemical nutrients, bottom substrate, water depth, water clarity or turbidity, and currents.


Contd..

Coral reefs, for example, require very low turbidity (maximum light), moderate to high temperatures (tropical climates), shallow depths (for effective light penetration and temperature limitations), and moderate to high salinity (30 - 40 ppt) to survive.

A coral reef ecosystem will not develop if all of these abiotic factors are not met.



Biosphere 2 is an Earth systems science research facility currently owned by the University of Arizona since 2011. Its current mission is to serve as a center for research, outreach, teaching and lifelong learning about Earth, its living systems, and its place in the universe. It is a 3.14-acre (12,700 m2) structure originally built to be an artificial, materially closed ecological system in Oracle, Arizona (US)


Mission-Biosphere 2

To serve as a center for research, outreach, teaching and life-long learning about Earth, its living systems, and its place in the universe.

Catalyze interdisciplinary thinking and understanding about Earth and its future.

Be an adaptive tool for Earth education and outreach to industry, government, and the public.

Distill issues related to Earth systems planning and management for use by policymakers, students and the public.


Biosphere 2 arena

Oracle, Arizona (US)


Image Galler

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Queries…..!


M s . A s h i l a B a b u . PI S e m e s t e r , M a s t e r s D e p t . E n v i r o n m e n t a l S c i e n c e sC e n t r a l U n i v e r s i t y o f Ke r a l a

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Global environmental segments and its structures

Education