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

1. HAFIZ
MUHAMMAD
WASEEM
LAHORE
PAKISTAN

2. Applied Ecology
ZOOL3118

3. Key Topic
• Biogeochemical Cycles
• Phosphorus cycle
“Bio” refers to living organisms and “geo” to the rocks, soil, air and water
of the earth
UNIVESITY OF EDUCATION LAHORE
PAKISTAN

4. • According to the law of conservation of matter, matter is neither created
nor destroyed
• The earth neither receives matter nor does it lose to outer space
• Elements must have been used over and over
• 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. Phases of Biogeochemical Cycles
• There are two classes of abiotic phases in biogeochemical cycles
• Sedimentary phase
• Atmospheric phase
• In some cycles, such as nitrogen, the atmospheric phase is more important
than the sedimentary------- atmosphere reservoir cycles
• In others, such as phosphorus, the atmospheric phase is essentially non-
existent------sediment-reservoir cycles
• In still others, such as sulphur, both phases are present

7. TYPES OF BIOGEOCHEMICAL CYCLES
• There are two types of biogeochemical cycles,
• Gaseous biogeochemical cycles (Atmosphere and ocean)
• Sedimentary biogeochemical cycles (Earth crust)
• Both involve biotic and abiotic agents
• Both are driven by the flow of energy
• Both are tied to the water cycle

8. Phosphorus cycle
• Phosphorus is essential to living things as:
• Energetics……….ATP, ADP, cAMP
• Genetics………….RNA, DNA
• Structure…………Phospholipid
• The ultimate source of phosphate in the ecosystem is crystalline rocks
• As these are eroded and weathered, phosphate is made available to living
organisms, generally as ionic phosphate

9. Phosphorus cycle
• It occurs naturally in environment as phosphate (PO4¯, or one of its
analogues, HPO4¯ or H2PO4¯)
• as soluble inorganic phosphate ions
• as soluble organic phosphate
• as particulate phosphate
• as mineral phosphate
• Phosphorus cycle has no atmospheric phase

10. Phosphorus cycle
• Phosphorus is introduced into autotrophic plants through their roots, where it is
incorporated into living tissues
• Mycorrhizae play key role in uptake of phosphorus by plants in terrestrial
ecosystem.
• From autotrophs, it is passed along the grazing food chain
• with excess phosphate being excreted in the feces…….Guano
• Phosphates can be released as particulate matter from forest and grassland fires.

11. • In the detritus food chain, large organic molecules containing phosphate
are degraded and the phosphate is liberated as inorganic ionic phosphate
• In this from it can be immediately taken up by autotrophs, or it can be
incorporated into a sediment particle, either in the soil of a terrestrial
ecosystem or in a sediment of an aquatic ecosystem.
• The sedimentary phase of phosphorous cycle remains comparatively slow
than the organic phase.

13. • Human activities are affecting the phosphorous cycle by:
• Removing large amounts of phosphate from the earth to make fertilizer
• Reducing phosphorus in tropical soils by clearing forests
• Soil that is eroded from fertilized crop fields carries large quantities of
phosphates into streams, lakes, and the ocean, where it stimulates the
growth of producers
• Phosphorous-rich runoff from the land can produce huge populations of
algae, which can upset chemical cycling and other processes in lakes