Download Nutrient Cycles

Ecology Unit
Nutrient Cycles
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Nutrient Cycles
• The most common
elements in biological
molecules: Carbon,
Nitrogen, Hydrogen,
Oxygen, Sulfur,
Phosphorus
• These elements cycle
through the biosphere,
hydrosphere, geosphere
and atmosphere.
Nutrient Cycles
All Nutrient Cycles include 3
key steps:
•Producers take up
chemicals from the
nonliving environment (soil,
water, air) and create
organic compounds
•Consumers feed on
producers and use the
chemicals for energy or
structures. Some of the
chemicals return to the
environment as waste
products.
•Dead organisms are broken
down by decomposers,
returning chemicals to the
soil, water and air in
inorganic forms.
Carbon Cycle
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Why is Carbon important?
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All organic compounds (proteins, carbohydrates,
nucleic acids, and lipids) contain carbon.
1 in every 10 atoms in a human body is carbon
Forms structures
Provides energy
Carbon Cycle
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The Carbon Cycle
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Carbon is “fixed’ by producers - producers absorb CO2
from the atmosphere during photosynthesis to produce
glucose.
Consumers take up carbon by eating plants
Carbon returns to atmosphere through cellular
respiration
Carbon enters soil from animal waste and
decomposition
Carbon in the soil can be converted to fossil fuels
Carbon can also be absorbed by the oceans
Burning fossil fuels returns CO2 to the atmosphere
Carbon-rich rocks, like limestone, release carbon to the
atmosphere through weathering.
Carbon
Cycle
Water Cycle
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The Water Cycle
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Solar energy evaporates water from land and ocean,
adding water vapor to the atmosphere
The water cools and condenses, forming precipitation.
Plants absorb water from soil
Consumers take up water directly or from plants they
consume
Plants lose water to the atmosphere through
transpiration
• Most of the water cycle takes place between the
atmosphere and the oceans in evaporation and
precipitation.
Water Cycle
Nitrogen Cycle
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The Nitrogen Cycle
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N2 from the atmosphere is fixed by bacteria in the soil and in
the roots of some plants to form ammonia (NH3)
Bacteria also convert ammonium (NH4+) from the soil to form
nitrates. This process is called nitrification.
Producers absorb ammonia and nitrates from the soil and
convert them to amino acids.
Consumers obtain nitrogen from plants
Ammonium returns to the soil from waste and
decomposition
Denitrifying bacteria convert some nitrates back to N2 and
release to the atmosphere.
Lightening can also create enough pressure and energy to
convert N2 to ammonia (NH3)
Nitrogen Cycle
Little nitrogen is
exchanged with
atmosphere
Fertilizer is a source
of a significant
amount of nitrogen