Download Natural Resources - IDMVS-Lab

DMC-104: Geography and Environment
Course Teacher:
Dr. Syed Hafizur Rahman (SHR)
M. Sc. (JU), Ph. D. (Birmingham University, United Kingdom)
Permanent Position
Professor
Department of Environmental Sciences
Jahangirnagar University, Dhaka-1342
E-mail:
Day & Time:
[email protected]
03:00 to 04:00PM (Wed & Thu)
14 March 2013
Last Lecture
Physical Geography:
Earth’s Surface:
Internal Geological Processes,
External Processes,
Fluvial and Karst Processes,
Glaciations,
Desert Landforms,
Ocean Margins,
Earth’s Climates:
The Atmosphere,
Global Climates,
Cloud Formation,
Storms.
This Lecture
Biogeography and Natural Resources:
Earth’s Biological Systems (Biomes, Forests, Grasslands, Deserts,
Tundra and High Altitude Biomes, National Park Systems),
Natural Resources (Soils, Water, Renewable Resources, Nonrenewable
Resources)
Human Geography:
Human Society and the Earth (The Human Environment, Population
Growth and Distribution, Global Urbanization, Global Time and Time
Zones),
Climate and Human Societies (Climate and Human Settlement, Flood
Control, Atmospheric Pollution, Disease and Climate),
Exploration and Transportation (Exploration and Historical Trade
Routes, Road Transportation, Railroads, Air Transportation).
Biogeography and Natural
Resources
Earth’s Biological Systems: Biomes
• The major recognizable life zones of the continents, biomes
are characterized by their plant communities.
• Temperature, precipitation, soil, and length of day affect
the survival and distribution of biome species.
• Species diversity within a biome may increase its stability
and capability to deliver natural services, including
enhancing the quality of the atmosphere, forming and
protecting the soil, controlling pests, and providing clean
water, fuel, food, and drugs.
• Land biomes are the temperate, tropical, and boreal
forests; tundra; desert; grasslands; and chaparral.
Temperate Forest
• The temperate forest biome occupies the so-called temperate
zones in the mid-latitudes (from about 30 to 60 degrees north
and south of the equator).
• Temperate forests are found mainly in Europe, eastern North
America, and eastern China, and in narrow zones on the coasts
of Australia, New Zealand, Tasmania, and the Pacific coasts of
North and South America.
• Their climates are characterized by high rainfall and
temperatures that vary from cold to mild.
• Temperate forests contain primarily deciduous trees—including
maple, oak, hickory, and beechwood—and, secondarily,
evergreen trees— including pine, spruce, fir, and hemlock.
Tropical Forest
• Tropical forests are in frost-free areas between the Tropic
of Cancer and the Tropic of Capricorn.
• Temperatures range from warm to hot year-round,
because the Sun’s rays shine nearly straight down around
midday.
• These forests are found in northern Australia, the East
Indies, southeastern Asia, equatorial Africa, and parts of
Central America and northern South America.
• Tropical forests have high biological diversity and contain
about 15 percent of the world’s plant species.
• Animal life lives at different layers of tropical forests.
Boreal Forest
• The boreal forest is a circumpolar Northern Hemisphere
biome spread across Russia, Scandinavia, Canada, and
Alaska.
• The region is very cold.
• Evergreen trees such as white spruce and black spruce
dominate this zone, which also contains larch, balsam,
pine, and fir, and some deciduous hardwoods such as
birch and aspen.
Tundra
• About 5 percent of the earth’s surface is covered with
Arctic tundra, and 3 percent with alpine tundra.
• The Arctic tundra is the area of Europe, Asia, and North
America north of the boreal coniferous forest zone,
where the soils remain frozen most of the year.
• Arctic tundra has a permanent frozen subsoil, called
permafrost.
• Deep snow and low temperatures slow the soil-forming
process.
Desert
• The desert biome covers about one-seventh of the earth’s
surface.
• Deserts typically receive no more than 10 inches (25
centimeters) of rainfall a year, but evaporation generally
exceeds rainfall.
• Deserts are found around the Tropic of Cancer and the Tropic
of Capricorn.
• As the warm air rises over the equator, it cools and loses its
water content.
• This dry air descends in the two subtropical zones on each side
of the equator; as it warms, it picks up moisture, resulting in
drying the land. Rainfall is a key agent in shaping the desert.
Grassland
• Grasslands cover about a quarter of the earth’s surface,
and can be found between forests and deserts.
• Treeless grasslands grow in parts of central North America,
Central America, and eastern South America that have
between 10 and 40 inches (250-1,000 millimeters) of
erratic rainfall.
• The climate has a high rate of evaporation and periodic
major droughts.
• The biome is also subject to fire.
Mediterranean
• The Mediterranean biome is found in the Mediterranean
Basin, California, southern Australia, middle Chile, and
Cape Province of South Africa.
• In California it is known as chaparral. This region has a
climate of wet winters and summer drought.
• The plants have tough leathery leaves and may contain
thorns.
• Regional fires clear the area of dense and dead vegetation.
Fire, heat, and drought shape the region.
• The vegetation dwarfing is due to the severe drought and
extreme climate changes.
Ocean
• The ocean biome covers more than 70 percent of the
earth’s surface and includes 90 percent of its volume.
• The ocean has four zones. The intertidal zone is shallow
and lies at the land’s edge.
• The continental shelf, which begins where the intertidal
zone ends, is a plain that slopes gently seaward.
• The neritic zone (continental slope) begins at a depth of
about 600 feet (180 meters), where the gradual slant of the
continental shelf becomes a sharp tilt toward the ocean
floor, plunging about 12,000 feet (3,660 meters) to the
ocean bottom, which is known as the abyss.
• The abyssal zone is so deep that it does not have light.
Human Impact on Biomes
• Human interaction with biomes has increased biotic
invasions, reduced the numbers of species, changed
the quality of land and water resources, and caused
the proliferation of toxic compounds.
• Managed care of biomes may not be capable of
undoing these problems.
Natural Resources
Natural Resources: Introduction
• Our environment provides us with a variety of goods and
services necessary for our day to day lives.
• These natural resources include, air, water, soil, minerals,
along with the climate and solar energy, which form the
non-living or ‘abiotic’ part of nature.
• The ‘biotic’ or living parts of nature consists of plants and
animals, including microbes. Plants and animals can only
survive as communities of different organisms, all closely
linked to each in their own habitat, and requiring specific
abiotic conditions.
• Interactions between the abiotic aspects of nature and
specific living organisms together form ecosystems of
various types.
Earth’s Resources and Man
• The resources on which mankind is dependent are
provided by various sources or ‘spheres’: Atmosphere,
Hydrosphere, Lithosphere, Biosphere.
1) Atmosphere
– Oxygen for human respiration (metabolic
requirements).
– Oxygen for wild fauna in natural ecosystems and
domestic animals used by man as food.
– Oxygen as a part of carbon dioxide, used for the growth
of plants (in turn are used by man).
Earth’s Resources and Man
2) Hydrosphere
•
Clean water for drinking (a metabolic requirement for
living processes).
• Water for washing and cooking.
• Water used in agriculture and industry.
• Food resources from the sea, including fish, crustacea, sea
weed, etc.
• Food from fresh water sources, including fish, crustacea
and aquatic plants.
• Water flowing down from mountain ranges harnessed to
generate electricity in hydroelectric projects.
Earth’s Resources and Man
3) Lithosphere
• Soil, the basis for agriculture to provide us with food.
• Stone, sand and gravel, used for construction.
• Micronutrients in soil, essential for plant growth.
• Microscopic flora, small soil fauna and fungi in soil, important
living organisms of the lithosphere, which break down plant
litter as well as animal wastes to provide nutrients for plants.
• A large number of minerals on which our industries are based.
• Oil, coal and gas, extracted from underground sources. It
provides power for vehicles, agricultural machinery, industry,
and for our homes.
Earth’s Resources and Man
4) Biosphere
• Food, from crops and domestic animals, providing human
metabolic requirements.
• Food, for all forms of life which live as interdependent
species in a community and form food chains in nature on
which man is dependent.
• Energy needs: Biomass fuel wood collected from forests
and plantations, along with other forms of organic matter,
used as a source of energy.
• Timber and other construction materials.
Natural Resources:
Renewable/Nonrenewable
• Ecosystems act as resource producers and processors.
• Solar energy is the main driving force of ecological systems,
providing energy for the growth of plants in forests, grasslands
and aquatic ecosystems.
• A forest recycles its plant material slowly by continuously
returning its dead material, leaves, branches, etc. to the soil.
• Grasslands recycle material much faster than forests as the
grass dries up after the rains are over every year.
• All the aquatic ecosystems are also solar energy dependent
and have cycles of growth when plant life spreads and aquatic
animals breed.
• The sun also drives the water cycle.
Non-renewable resources
• These are minerals that have been formed in the
lithosphere over millions of years and constitute a closed
system.
• These non-renewable resources, once used, remain on
earth in a different form and, unless recycled, become
waste material.
• Non-renewable resources include fossil fuels such as oil
and coal, which if extracted at the present rate, will soon
be totally used up.
• The end products of fossil fuels are in the form of heat and
mechanical energy and chemical compounds, which cannot
be reconstituted as a resource.
Renewable resources
• Though water and biological living resources are
considered renewable. They are in fact renewable only
within certain limits. They are linked to natural cycles such
as the water cycle.
• Fresh water (even after being used) is evaporated by the
sun’s energy, forms water vapour and is reformed in clouds
and falls to earth as rain. However, water sources can be
overused or wasted to such an extent that they locally run
dry. Water sources can be so heavily polluted by sewage
and toxic substances that it becomes impossible to use the
water.
• Forests, once destroyed take thousands of years to regrow
into fully developed natural ecosystems with their full
complement of species. Forests thus can be said to behave
like non-renewable resources if overused.
• Fish are today being over-harvested until the catch has
become a fraction of the original resource and the fish are
incapable of breeding successfully to replenish the population.
• The output of agricultural land if mismanaged drops
drastically.
• When the population of a species of plant or animal is
reduced by human activities, until it cannot reproduce fast
enough to maintain a viable number, the species becomes
extinct.
• Many species are probably becoming extinct without us even
knowing, and other linked species are affected by their loss.
ROLE OF AN INDIVIDUAL IN CONSERVATION
OF NATURAL RESOURCES
• Until fairly recently mankind acted as if he could go on for
ever exploiting the ecosystems and natural resources such
as soil, water, forests and grasslands on the Earth’s surface
and extracting minerals and fossil fuels from underground.
• But, in the last few decades, it has become increasingly
evident that the global ecosystem has the capacity to
sustain only a limited level of utilization.
• Biological systems cannot go on replenishing resources if
they are overused or misused. At a critical point, increasing
pressure destabilizes their natural balance.
ROLE OF AN INDIVIDUAL IN CONSERVATION
OF NATURAL RESOURCES
• Even biological resources traditionally classified as
‘renewable’ - such as those from our oceans, forests,
grasslands and wetlands, are being degraded by overuse
and may be permanently destroyed.
• And no natural resource is limitless. ‘Non-renewable’
resources will be rapidly exhausted if we continue to use
them as intensively as at present.
• The two most damaging factors leading to the current rapid
depletion of all forms of natural resources are increasing
‘consumerism’ on the part of the affluent sections of
society, and rapid population growth.
Next class
Human Geography