Nutrient cycle by Uday sir
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Transcript of Nutrient cycle by Uday sir
What Sustains Life on Earth?
• Solar energy, the cycling of matter, and gravity sustain the earth’s life.
Two Secrets of Survival: Energy Flow and Matter Recycle
• An ecosystem survives by a combination of energy flow and matter recycling.
Water’ Unique Properties• There are strong forces of attraction
between molecules of water.• Water exists as a liquid over a wide
temperature range. • Liquid water changes temperature
slowly.• It takes a large amount of energy for
water to evaporate.• Liquid water can dissolve a variety of
compounds.• Water expands when it freezes.
• Water moves through the biotic and abiotic factors in the environment
• Ways water can move:– Precipitation
• water moves from the atmosphere to the land in the form of snow, rain, sleet and hail.
• During evaporation and transpiration (evaporation from plants and through skin) water cools and condenses, precipitation forms
• About 91% falls into oceans. The rest falls on land to replenish the fresh water supply – Evaporation• Water moves from the land to the
atmosphere• Ground Water – when precipitation seeps
into the ground and becomes part of the water table
RunoffWater that flows on top of the ground
The Carbon Cycle• All living things have carbon in them• All carbon that is on earth has been here
since the earth was formed• Photosynthesis – carbon gets taken out of
the air and used by producers to make food• Respiration- carbon gets put back into the
air by animals when they exhale• Decomposition – breakdown of dead
materials by bacteria and fungi• Combustion – carbon in fossil fuels is
released while burning
The Carbon Cycle
Driven by biological forces:photosynthesis and respiration
15%/year
CO2 & CH4
The Nitrogen Cycle
• 78% of the earth’s atmosphere is nitrogen• Organisms cannot use nitrogen directly from
atmosphere• Nitrogen fixation- when bacteria in the soil
change atmospheric nitrogen gas into usable nitrogen
• Lightening can also fix nitrogen• Denitrification-different bacteria change
usable nitrogen into atmospheric nitrogen gas
Nitrogen Cycle• natural cyclic
process in the course of which atmospheric nitrogen enters the soil and becomes part of living organisms
Steps of Nitrogen Cycle• Nitrogen Fixation• Nitrogen Assimilation• Ammonification• Nitrification• Denitrification
Nitrogen Fixation• nitrogen gas is converted into
inorganic nitrogen compounds. It is mostly (90 percent) accomplished by free-living, nitrogen-fixing bacteria.
Nitrogen-Fixing Bacteria• symbiotic bacteria living on the
roots of plants (mostly legumes and alders)
• cyanobacteria (formerly known as blue-green algae)
• archaebacteria (also known as archaea) in deep-sea hydrothermal vents
Nitrogen Fixation by Lightning• The high energies provided by
lightning and cosmic radiation serve to combine atmospheric nitrogen and oxygen into nitrates, which are carried to the Earth’s surface in precipitation.
Steps of Nitrogen Cycle• Nitrogen Fixation• Nitrogen Assimilation• Ammonification• Nitrification• Denitrification
Nitrogen Assimilation• are assimilation of nitrates and
ammonia resulting from nitrogen fixation into the specific tissue compounds of algae and higher plants. Animals then ingest these algae and plants, converting them into their own body compounds.
Steps of Nitrogen Cycle• Nitrogen Fixation• Nitrogen Assimilation• Ammonification• Nitrification• Denitrification
Ammonification• The remains of all living things—
and their waste products—are decomposed by microorganisms which yields ammonia.
Steps of Nitrogen Cycle• Nitrogen Fixation• Nitrogen Assimilation• Ammonification• Nitrification• Denitrification
Nitrification• a process carried out by nitrifying
bacteria, transforms soil ammonia into nitrates, which plants can incorporate into their own tissues.
Steps of Nitrogen Cycle• Nitrogen Fixation• Nitrogen Assimilation• Ammonification• Nitrification• Denitrification
Denitrification• The process where nitrates are
metabolized by denitrifying bacteria to free nitrogen and returned to the atmosphere
Oxygen Cycle:
oxygen
respiration
carbondioxide
photosynthesis