unit 1

Environment

Environment is sum total of water, air and

land, inter-relationships among

Scope

1. Natural Resources – Their conversion and management

2. Ecology and biodiversity

3. Environmental pollution and control

4. Social issues in relation to development and environment

5. Human population and environment 6. Environmental Science, Engineering,

Importance

Environmental Issues

• _{There is a need for trained manpower to deal with}

environmental issues.

• _{Environmental law, business administration and}

environmental engineering are emerging as new career opportunities for environmental protection and management.

• _{With the pollution control laws becoming more stringent,}

industries are finding difficulties in dispose off the produced wastes.

• _{In order to avoid expensive litigation, various companies are}

NEED FOR PUBLIC AWARENESS

• Man should remember that he is a part of the environment

• He uses more materials, energy for agriculture, industry, transport, communication, comfort, war etc.,

• Humans are depleting and degrading the vital life (air, water and land)

Components of the environment

1. Abiotic or non-living component

2. Biotic or living component

Abiotic or non-living component or physical component

• _{These abiotic components enter the body of}

living organisms directly or indirectly, take part in metabolic activities and then return to the

environment.

• _{These abiotic component are sub divided into}

three categories 1. Atmosphere

I. Atmosphere

• The atmosphere is essential for living beings • It extends upto 500 kms from the earth surface.

• It comprises 78% nitrogen, 21% oxygen and 1% of other gases. • Structure of atmosphere – types

1. Traposphere - 75% atmospheric air mass (10-18 kms) – CO2, N2, O2 – 15 to 56ºC

2. Stratosphere – rich in ozone gas (18- 50 kms) - -56 to -2ºC 3. Mesosphere - (50-85 kms) – N2, O2 - -2 to -92ºC

Functions of atmosphere

1. It maintains the heat balance on the earth by absorbing the IR radiations

Functions of atmosphere

Gaseous Constituent Functions

Oxygen Supports life of living organisms

Carbon-dioxide Essential for photosynthetic activity of plants

II. Lithosphere

• _{The soil and rock components of the earth is}

called lithosphere

• _{Functions of lithosphere}

1. It is a home beings and wildlife

III. Hydrosphere

• _{The aqueous envelope of the earth (75% of}

the earth surface) is called hydrosphere.

• _{Oceans, lakes, streams, rivers and water}

vapour constitute hydrosphere.

• _{About 97% of earth’s water is in oceans, which}

Functions of Hydrosphere

• _{It is used for drinking purpose and also}

supports the aquatic life

• _{It is also used for irrigation, power production,}

Biotic (or) Living Conponent

• _{The living component of the environment are}

called iotic components.

• _{The biological environment where the living}

Functions of biosphere

• _{Plants through photosynthesis produce}

oxygen in the atmosphere.

• _{Animals inhale oxygen during respiration and}

Energy components

• _{The component of energy flows across biotic}

Status of various components of the environment due to human interventions

• _{Emission of green house gases – rise the}

average temperature of the earth several degrees by 2050.

• _{Chlorofluorocarbons and halogens – depleting}

the ozone layer – skin cancer, eye cataracts, affects immune system.

• _{Industrial emissions – SO2, NO2 – Acid rain –}

• Deforestation – 36,500 species of plants – extinct each year

• Destruction of wetlands and coral reefs – 500,000

• Today 10 million people worldwide lost their homes, land – environmental degradation.

• About 1.8 million square Kms of one productive land have become desert in the last 50 years

• Top soil erosion

• Millions of hectares of grasslands have been overgrazed

• 25-50% of the wetlands – drained, builtupon or seriously polluted.

Summary of environmental issuses and

options

Ambient air pollution

• _Effects

- _{Health problems}

- _{Economic costs from health care costs and} productivity losses

Causes – Air pollution

• _{Industrialization}

• _{Increase in motorized fleet and congestion} • _{Use of highly polluting fuels}

Management options

• _{Fuel pricing}

• _{Standard emission charges} • _{Transport planning}

• _{Appropriate technology (clean fuels, air pollution}

Indoor air pollution

- _{Chronic lung disease, Acute respiratory infections,}

low birth weights, cancer • _Causes

- _{Use of low quality fuels (high sulphur coal) for}

cooking and heating • _{Management options}

Surface water pollution

• _Effects

- _{Health problems}

- _{Economic costs (additional treatment costs)} - _{Amenity losses}

• _Causes

- _{Urban runoff} - _{Poor regulations}

- _{Industrial disposal practices} - _{Irrigation practices}

• _{Management options}

Groundwater pollution

• _Effects

- _{Reduced water quality from saline intrusion} • _Causes

- _{Unsustainable extraction} - _{Poor regulations}

Other environmental issues

• _{Coastal/lake pollution}

• _{Degradation of land}

• _{Loss of cultural and historical property}

• _{Degradation of ecosystems}

• _{Municipal solid wastes}

• _{Hazardous wastes}

• _{Natural and manmade hazards}

• _{Inadequate sanitation}

Objective type questions

1. which component of the environment are effective transporters

2. Which of the following not related to loss of productivity of croplands

a. Desertification b. Waterlogging

3. Biosphere is

a. The solid shell of inorganic materials

b. Organic matter on the surface of earth along with living things

4. Example of impact of developmental activities on the hydrosphere

a. Air pollution b. Soil pollution c. Soil erosion

5. Global atmospheric temperatures are likely to be increased due to

a. Burning of fossil fuels b. Water pollution

c. Soil erosion

6. Management option for air pollution

a. Regulation and standards b. Emission charges

Ecology

• _{Ecology is the study of interactions among}

organisms or group of organisms with their environment. The environment consists of both biotic components (living organisms) and abiotic components (non-living organisms).

(or)

Ecosystem

• _{A group of organisms interacting among}

Types of ecosystem

Ecosystem

Natural Artificial/ man engineered

Terrestial _Aquatic

Marine Fresh water

Components of ecosystem

1. Biotic Antotropic components (green plants)

Heterotrophic components

(macro consumers – herbivores, omnivores, carnivores

Saprotrophs – micro consumers – bacteria, fungi )

2. Abiotic physical components

(air, water, soil, sunlight) Chemical components

Abiotic Components:

• _{The non living factors or the physical environment}

prevailing in an ecosystem form the abiotic components. They have a strong influence on the structure,

distribution, behaviour and inter-relationship of organisms.

Abiotic components are mainly of two types: (a) Climatic Factors:

Which include rain, temperature, light, wind, humidity etc.

(b) Edaphic Factors:

The functions of important factors in abiotic

components are given below:

• Soils -Soils provide nutrients, water, a home, and a struc tural growing medium for organisms. The vegetation found growing on top of a soil is closely linked to this component of an ecosystem through nutrient cycling.

• The atmosphere provides organisms found within ecosystems with carbon di oxide for photosynthesis and oxygen for respiration. The processes of evapora tion,

transpiration and precipitation cycle water between the atmosphere and the Earth’s surface.

• Solar radiation is used in ecosystems to heat the atmosphere and to evapo rate and transpire water into the atmosphere. Sunlight is also necessary for photosynthesis. Photosynthesis provides the energy for plant growth and me tabolism, and the

organic food for other forms of life.

• Most living tissue is composed of a very high percentage of water, up to and even exceeding 90%. The protoplasm of a very few cells can survive if their water

content drops below 10%, and most are killed if it is less than 30-50%.

Biotic Components

(A) Producers:

• _{The green plants have chlorophyll with the help of}

which they trap solar energy and change it into chemical energy of carbohydrates using simple inorganic compounds namely water and carbon

dioxide. This process is known as photo synthesis. As the green plants manufacture their own food they are known as Autotrophs (i.e. auto = self, trophos = feeder)

• _{The chemical energy stored by the producers is utilised}

partly by the producers for their own growth and

The consumers are of four types, namely

(a) Primary Consumers or First Order Consumers or Herbivores:

These are the animals which feed on plants or the producers. They are called her bivores. Examples are rabbit, deer, goat, cattle etc.

(b) Secondary Consumers or Second Order Consumers or Primary Carnivores:

The animals which feed on the herbivores are called the pri mary carnivores. Examples are cats, foxes, snakes etc.

(c) Tertiary Consumers or Third Order Consumers:

These are the large carnivores which feed on the secondary consumers. Example are Wolves.

(d) Quaternary Consumers or Fourth Order Consumers or Omnivores: These are the largest carnivores which feed on the tertiary consumers and

(C) Decomposers or Reducers:

• _{Bacteria and fungi belong to this category. They}

breakdown the dead organic materials of producers (plants) and consumers (animals) for their food and re

lease to the environment the simple inorganic and organic substances produced as by-products of their metabolisms.

• _{These simple substances are reused by the producers}

Sustaining Life on Earth…

One way flow of high quality

energy

The cycling of

matter (the earth is a closed system) Gravity Causes downward movement of matter Biosphere Carbon

cycle Phosphoruscycle Nitrogencycle Watercycle Oxygencycle

Heat in the environment

Energy passes through trophic levels

One of the most important species interactions is who eats whom

Matter and energy move through the community

Trophic levels = rank in the feeding hierarchy

Producers Consumers

Biotic Components of Ecosystems

Source of all food Photosynthesis

Consumers=heterotroph

Aerobic respiration Anaerobic respiration

• Methane, H₂S

Decomposers

Matter recyclers…

Detritivores vs Decomposers

Fig. 4.15, p. 75 Mushroo m Wood reduced to powder Long-horned beetle holes Bark beetle engraving Carpenter ant galleries Termite and carpenter ant work

Dry rot fungus

Detritus feeders Decomposers

Energy Flow and Matter Cycling in Ecosystems…

Food Chains vs. Food Webs

KEY: There is little if no matter waste in natural ecosystems!

Heat Heat Heat Heat

Heat

Heat

Heat

First Trophic Level

Second Trophic Level

Third Trophic Level

Fourth Trophic Level

Solar energy

Producers

(plants) consumersPrimary (herbivores) Tertiary consumers (top carnivores) Secondary consumers (carnivores) Detritvores

Food webs show relationships and

energy flow

Food chain = the relationship of how energy is transferred up the trophic levels

Food web = a visual map of feeding relationships and energy flow

Includes many different organisms at all the various levels

Generalized Food Web of the Antarctic

Fig. 4.18, p. 77

Humans

Blue whale Sperm whale

Crabeater seal Killer whale _Elephant seal Leopard seal Adélie penguins Petrel Fish Squid Carnivorous plankton Krill Phytoplankton Herbivorous zooplankton Emperor penguin Note: Arrows

Pyramids of Energy and Matter

Pyramid of Biomass

Heat Heat Heat Heat Heat 10 100 1,000 10,000 Usable energy Available at Each tropic level

Carbon Cycle

Can be stored in five major areas: 1. Living and dead organisms

2. Atmosphere (carbon dioxide) 3. Organic matter in soil

Estimated major stores of carbon on the Earth

Sink Amounts in Billions of

Metric Tons

Atmosphere 766

Soil Organic Matter 1500-1600 Ocean 38,000-40,000 Marine sediments and sedimentary

rocks 66,000,000 to 100,000,000 Terrestrial plants 540-610

Carbon in Oceans

Enters through diffusion (creates carbonic acid)

Some sea life use bicarbonate to

Carbon cycle in the lithosphere

Inorganic: coal, oil, natural gas, oil shale, limestone

Created from

Carbon cycle in the soil

Organic: litter,

Humans and the Carbon Cycle

Until recently: none Now: 6.5 billion

metric tons of carbon are

transferred from fossil fuel storage pool to the

The Source of High Quality Energy

Energy of sun

lights and warms the planet

Supports photosyn. Powers the

cycling of matter Drives climate and weather that distribute heat and H₂O

Solar

radiation Energy in = Energy out

Reflected by atmosphere (34%) UV radiation Absorbed by ozone Absorbed by the earth

Visible light Lower Stratosphere (ozone layer) Troposphere Heat Greenhouse effect Radiated by atmosphere as heat (66%)

Earth

Carbon in Ecosystems:

Photosynthesis and Respiration

Forms of C: CO₂, organic C compounds like glucose

Processes

Photosynthesis: Carbon dioxide + water + solar energy chlorophyll _glucose (sugar) + oxygen

Respiration: Glucose +

Fate of Solar Energy…

Earth gets 1/billionth of sun’s output of nrg 34% is reflected away by atmosphere

66% is absorbed by chemicals in atm = re-radiated into space

Visible light, Infrared radiation (heat), and a small amount of UV not absorbed by ozone reaches the atmosphere

Energy warms troposphere and land

Evaporates water and cycles it along with gravity Generates winds

A tiny fraction is captured by photosynthesizing organisms

Primary Productivity

energy to chemical energy is called “gross primary

production.”

Plants use the energy

captured in photosynthesis for maintenance and growth. The energy that is

Primary Productivity

GPP= RATE at which producers convert solar energy into chemical energy as biomass

Rate at which producers use photosynthesis to fix

inorganic carbon into the organic carbon of their tissues These producers must use some of the total biomass they produce for their own respiration

NPP= Rate at which energy for use by consumers is stored in new biomass (available to consumers)

Units Kcal/m2_{/yr or g/m}2_/yr

How do you measure it? AP Lab Site

dO2

What are the most productive Ecosystems?

Estuaries Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Lakes and streams Continental shelf Open ocean Tundra (arctic and alpine) Desert scrub Extreme desert

800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600

Nutrient pollution

Pollution = the release of matter or energy

into the environment that causes undesirable impacts on the health and well-being of

Lakes vary in their nutrients and oxygen

Nutrient pollution from fertilizers, farms, sewage, lawns, golf courses

Leads to eutrophication

Oligotrophic lakes and ponds = have low nutrient and high oxygen conditions

Eutrophic lakes and ponds = have high nutrient and low oxygen conditions

Solutions

• Phosphate-free detergents

• Planting vegetation to increase nutrient uptake

• Treat wastewater

Eutrophication is a natural process, but…

Accelerated results with human input of nutrients to a lake

Eutrophication

Species can change communities

Trophic Cascade = predators at high trophic levels can indirectly affect populations of organisms at low trophic

levels by keeping species at intermediate trophic levels

in check

Extermination of wolves led to increased deer populations, which led to overgrazed vegetation and changed forest

structure

Ecosystem engineers = physically modify the environment

Surface Water

Surface runoff flows into streams, lakes, wetlands and reservoirs

A watershed or drainage basin

Region that drains into a streams, lakes, wetlands or reservoirs

Rivers and streams wind through landscapes

Water from rain, snowmelt, or springs forms streams, creeks, or brooks

These merge into rivers, and eventually reaches the ocean

Tributary = a smaller river slowing into a larger one

A river may shift course

Floodplain = areas nearest to the river’s course that are flooded periodically

Discharge and Sediment Load

Frequent deposition of silt makes floodplain soils fertile

Riparian = riverside areas that are productive and species-rich

Rivers shape the landscape

If there is a large bend in the river, the force of the water cuts through the land

Oxbow = an extreme bend in

a river

Oxbow lake = the bend is cut

off and remains as an

Wetlands include marshes, swamps, and bogs

Wetlands = systems that combine elements of

freshwater and dry land

Freshwater marshes = shallow water allows plants to grow above the water’s surface

Swamps = shallow water that occurs in forested areas

Can be created by beavers

Bogs = ponds covered in thick floating mats of vegetation

Wetlands are valuable

Wetlands are extremely valuable for wildlife They slow runoff

Reduce flooding Recharge aquifers Filter pollutants

People have drained wetlands, mostly for agriculture

WHAT IS THE PHOSPHORUS

CYCLE?

• _{The phosphorus cycle,} is the circulation of

phosphorous among the rocks, soils, water, and plants and animals of the earth. Human

beings and all other organisms must have phosphorus to live. In nature, most

• It cannot be found in air in the gaseous . This is because phosphorous is usually liquid at normal temperatures pressures.

• This cycle is the slowest of the matter cycles.

• Phosphorus is most

commonly found in rock formations and ocean sediments as phosphate salts. Phosphates are

THE PROCESS OF

THE

PHOSPHOROUS

CYCLE

• The cycle basically

starts out in the earth’s soil. The soil contains phosphate and when something grows out of the soil it should have phosphate as well.

• When the plants grow

they are consumed by herbivore and omnivore animals

• The animal’s waste or

the animal’s body when it dies becomes detritus.

• Detritus is non-living

organic material. When the detritus goes deep into the soil, detritivores in the soil decompose and become the soil’s

• Another example of the phosphorus cycle is when rocks are created.

• The phosphate in the soil moves on and transfers its phosphate to the rocks

underwater. When the uplifting of the rocks occurs it takes the

phosphate along with it. After that the weathering of rocks occur and the

rocks begin to break down into the soil and the

HOW DO HUMANS INTERFERE

WITH THE PHOSPHORUS CYCLE?

 _{Cutting and}

burning of tropical rain forests affects the phosphorus

cycle. As the forest is cut and/or

burned, nutrients originally stored in plants and rocks

are quickly washed away by heavy

 Agricultural runoff provides much of the phosphate

found in waterways. Crops often cannot absorb all of the fertilizer in the soils, causing excess fertilizer runoff and increasing

phosphate levels in rivers and other bodies of water. The phosphate in the water is eventually precipitated as sediments at the bottom of the body of water. In

certain lakes and ponds this may be re-dissolved and recycled as a problem nutrient.

_{Animal wastes or manure}

may also be applied to the land as fertilizer. If misapplied on frozen ground during the winter, much of it may lost as run-off during the spring thaw. In certain area very large feed lots of animals, may result in excessive run-off of phosphate and nitrate into streams.

• A major problem with the use of phosphorus in fertilizers is the process of artificial eutrophication. Eutrophication is a large increase in the primary productivity of a lake. Eutrophication can be harmful to the natural balance of a lake and result in massive death of fish and other animals as dissolved oxygen levels are depleted from the water.

_{Another human cause of artificial}

eutrophication is run-off from