I AM HAFIZ MUHAMMAD WASEEM from mailsi vehari BSc from science college Multan MSC university of education Lahore i love Pakistan and my teachers and my parents

1. HAFIZ
MUHAMMAD
WASEEM
LAHORE
PAKISTAN

2. Applied Ecology
ZOOL3118
UNIVESITY OF EDUCATION LAHORE
PAKISTAN

3. Key Topic
• Biogeochemical Cycles
• Water cycle
“Bio” refers to living organisms and “geo” to the rocks, soil, air and water
of the earth

4. • Mass of all the organisms on the earth in the past 1.5 billion years is much greater than
the mass of carbon and nitrogen atoms present
• According to the law of conservation of matter, matter is neither created nor destroyed
• carbon and nitrogen must have been used over and over
• The earth neither receives matter nor does it lose to outer space
• The atoms of each element is taken from the environment, made a part of an organism
and returned to the environment to be used over again
• The cyclic movements of chemical elements of the biosphere between the organism and
the environment are referred to as biogeochemical cycles
Biogeochemical cycles

5. Phases of Biogeochemical Cycles
• Organic Phase: Movement of elements through biotic communities via
food chains
• Abiotic Phase: Movement of elements external to food chain
• Flow in the abiotic phases is much slower than in the organic phase

6. Water/ Hydrologic Cycle
• Living organisms, atmosphere and earth maintain between them a
circulation of water and moisture, which is referred to as water cycle or
hydrologic cycle.
• without the cycling of water, biogeochemical cycles could not exist,
ecosystems could not function, and life could not be maintained.

7. Water is important for an ecosystem for several reasons
• it is the medium by which nutrients are introduced into autotrophic
plants;
• it is an important part of living tissue
• it serves as a means of thermal regulation
• it is the medium by which sediments are removed from or added to local
ecosystem
• it covers the majority of the earth’s surface
Water/ Hydrologic Cycle

8. • The hydrologic cycle is driven by solar energy and gravity
• More than 80% of the total solar radiation goes
to evaporate water
• The atmospheric water vapour then condense
called nucleation particles
• droplets formed becomes heavy enough to fall
as precipitation, due to gravity
• Hydrologic cycle can be defined as an alteration of evaporation and
precipitation, with the energy used

9. Distribution of water in earth’s surface
• Water is not evenly distributed throughout the earth
• Almost 95% of the total water on earth is chemically bound into rocks and
does not recycle
• Of the remainder, about 97.3% is in the ocean
• about 2.1% exists as ice in the polar caps and permanent glaciers,
• and the rest is fresh water, present in the form of atmospheric water vapour,
ground water, soil water, or inland surface water

10. The rate of cycling of water
• The rate of cycling between surface and atmosphere is very rapid
• The average rain fall for the earth is about 81.1cm and in some places it
ranges upto 1200cm
• The average time for atmospheric water is about 11.4 days
or
• all the water vapour in the entire atmosphere falls as precipitation and is
reevaporated more than 32 times per year

11. Nature of hydrologic cycles
• The hydrologic cycle is extremely simple
• the water is evaporated from the surface of the earth/ocean, form the clouds
that precipitate as rain
• several routes are open to precipitation that falls on land
1. rapidly cycling portion, or evapotranspiration
2. the less rapidly cycling water, or surface runoff
3. very slowly cycling ground water that seeps into the soil

12. Evapotranspiration
• Evaporation refers to water that is evaporated directly from any surface
other than a plant
• In some ecosystems, evaporation also leads to a concentration of salts in the
water of soil which may be a critical environmental factor
• Transpiration is water that evaporates from the surface of leaves of plants
• Transpiration acts to move the biogeochemical cycles for all mineral nutrients
that enter the food chain via the roots of plants

13. Surface runoff
• the gross movement of soluble and solid particles in the ecosystem is accomplished by runoff
• Nutrients that have accumulated in sediments or soils can be eroded by streams and removed
altogether from a local ecosystem
• soluble nutrients may be carried by soil seepage into surface waters, where they are removed
• Streams may carry sediment particles which can be chemically altered through additional
weathering so that the nutrient elements they contain may be utilized by organisms.
• Finally moving water acts as an agent of erosion which removes soil and allows weathering of the
underlying rock to make their nutrients available to plants.

14. Ground water
• Ground water is water that saturates either sediment or rock below the
water table.
• In general, it is not trapped by plants for transpiration and it is too deep to
be directly evaporated from the soil surface.
• It is an exceedingly important reservoir for water which moves from one
place to another under the influence of gravity

15. • The hydrologic cycle on land, thus, includes evapotranspiration of water
from earth’s surface and leaf surface
• → formation of clouds
• → precipitation
• → surface runoff + accumulation of water as ground water
• → return of water to sea via streams or direct evaporation and cloud
formation, and so on…………………..

18. We alter the water cycle by:
1. Withdrawal of large quantities of freshwater from streams, lakes, and underground
sources, sometimes at rates faster than nature can replace it
2. clearing the vegetation from land for agriculture, mining, road building etc.
• This increases runoff,
• reduces infiltration that would normally recharge groundwater supplies
• accelerates soil erosion and landslides
• alter weather patterns by reducing transpiration
• raises ground temperatures
3. we drain wetlands for farming and other purposes that results into increased flooding