Transcript Cycles of Matter

Cycles of Matter
Recycling in biosphere
• Energy has one-way flow through and
between ecosystems
Matter
• Unlike one-way flow of energy, matter is
recycled within and between ecosystems
• Biogeochemical cycles
– Connect biological, geological, and chemical
parts of the biosphere
• Biological systems do not use up matter,
they transform it
– Same molecules are passed around again and
again in the biosphere
The Water Cycle
• Water is moved or stored by
–
–
–
–
–
Evaporation
Transpiration
Precipitation
Retention
Transportation
The Carbon Cycle
• Carbon enters atmosphere (as CO2) by
aerobic respiration, fossil-fuel burning, and
volcanic eruptions
Carbon Cycle
Carbon is removed
from the atmosphere
(and bodies of water)
by photosynthesizers
and shelled
organisms
Carbon Cycle
• Decomposition of
buried carbon
compounds millions of
years ago caused
formation of fossil
fuels
Carbon Cycle
• Burning of fossil fuels puts extra amounts
of carbon dioxide into the atmosphere
– May lead to global warming
• The greenhouse effect
The Nitrogen Cycle
• Nitrogen gas (N2)
makes up 78% of
Earth’s atmosphere
• All organisms require
nitrogen to make
amino acids
• Amino acids are
essential for all life
Nitrogen Cycle
• Only certain types of bacteria
can use N2 directly
– They convert N2 to ammonia by
nitrogen fixation
– Other bacteria convert ammonia to
nitrates and nitrites
• Producers use these to make proteins
• Consumers eat the producers and
reuse the nitrogen to make their own
proteins
Nitrogen Cycle
• Organisms die; decomposers return nitrogen
to soil as ammonia
– May be taken up again by producers
– May be turned back into nitrogen gas by soil
bacteria
• Process called denitrification
• Releases nitrogen into the atmosphere again
The Phosphorous Cycle
• Part of DNA and RNA
• Not common in the biosphere
• Does not enter the atmosphere
– Remains mostly on land in rock, soil minerals
and ocean sediment
Phosphorous Cycle
• Rocks and sediments gradually wear down
and phosphate is released
– Some makes its way to the ocean to be used by
marine organisms
– Some stays on land and cycles between
organisms and the soil
Nutrient Limitation
• When an ecosystem is
limited by a single
nutrient that is scarce
or cycles slowly, the
substance is called a
limiting nutrient.
End