Transcript 1.3.Cycling of Matter Part2x

Cycling of Matter –
keeping the
sphere’s in balance
Part II
Let’s do an Overview of What You
Learned
• Biogeochemical Cycle – the movement of
matter through the biotic and abiotic
environment.
• Ecosystems provide the biotic component
with the abiotic components they need
• Often we refer to these abiotic necessities as
nutrients
• Examples of nutrients essential to living
things water, carbon and nitrogen
Ecosystem inputs
constant
energy flows
input
of
through
energy
nutrients cycle
Matter
cannot
Don’t forget
laws of or
bethe
created
Physics!
destroyed
nutrients
can only
cycle
biosphere
inputs
 energy
 nutrients
http://mff.dsisd.net/Environment/Cycles.htm
ENERGY & MATTER
Energy is not the only thing
that moves through the ecosystem.
Atoms are never destroyed . . . only
transformed.(recycled!)
Take a deep breath.
The atoms you just inhaled
may have been inhaled by
a dinosaur millions of years
ago.
http://educ.queensu.ca/~fmc/august2004/pages/dinobreath.html
4 ATOMS make up 95% of the body
in most organisms
ORGANIC: contain
INORGANIC:
OXYGEN
CARBON
both C and H atoms
HYDROGEN
Ex. Sugars C6H12O6,
fats, proteins, fuels
C5H10
do not contain both
C NITROGEN
and H
Ex. CO2, H2O, NH3
The same molecules are passed around
again and again within the biosphere in
BIOGEOCHEMICAL CYCLES
___________________________
THE WATER CYCLE
Water continually cycles through the earth’s
spheres.
1. The sun’s rays evaporate water from oceans and
other bodies of water (hydrosphere).
2. As the water vapour rises in the atmosphere, it cools
and condenses to form clouds
3. The water falls from the clouds as precipitation
4. As the water falls onto land (lithosphere), it eventually
makes its way back into the oceans/lakes, via runoff,
into ground water, etc. (hydrosphere)
5. Plants and animals intake water and then release it
through cellular respiration; plants also transpire
(biosphere).
This is how water cycles through the 4 spheres
Impacts to water cycle????
WHY IS WATER IMPORTANT?
Makes up 60-70% of your body
Oxygen and Hydrogen are found in all the
building blocks of cells:
carbohydrates, proteins,
nucleic acids, lipids
Hydrogen in H2O supplies
+
protons (H ) & electrons
For photosynthesis
http://www.lsbu.ac.uk/water/molecule.htm
WHY IS WATER IMPORTANT?
Water is a universal solvent
- i.e. many molecules dissolve in water so it
provides a place for chemical reactions
to happen
Water doesn’t change temperature easily so
it helps with temperature regulation
Water is more dense in liquid form
than solid form – so ice floats.
http://www.lsbu.ac.uk/water/molecule.htm
NITROGEN CYCLE
THE NITROGEN CYCLE IN
TERRESTRIAL ECOSYSTEMS
• Most N
used is taken from the atmosphere,
changed into useable forms by nitrogen fixing
bacteria (biosphere, lithosphere, hydrosphere)
2
•
Plants absorb nitrogen from the soil & water,
and as organisms eat plants, this nitrogen
enters the food chain (biosphere)
• When organisms die, decomposers convert
nitrate back into nitrogen gas, returning it to
the atmosphere, or back into the ammonia in
the soil (lithosphere)
• Nitrogen is also returned to the atmosphere as
ammonia during volcanic eruptions.
(lithosphere).
• Lightening can also ‘fix’ N
lithosphere)
2
(atmosphere 
• In a sustainable ecosystem, the amount of
nitrogen that is converted to other forms
(ammonia, ammonium, nitrate) is EQUAL to
the amount that is returned to the atmosphere.
• However – humans also add N via fertilizers
into ecosystems  impact = eutrophication
NITROGEN CYCLE
Section 3-3
N2 in Atmosphere
NO3and NO2-
NH3
BIOLOGY; Miller and Levine; Prentice Hall; 2006
WHY IS NITROGEN IMPORTANT?
Nitrogen Bases make DNA and RNA
Adenine (nitrogen base) is used to make energy for cells
Makes AMINO part of amino acids (proteins)
Image by Riedell
http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm
Image by Riedell
79% of the atmosphere is made
up of NITROGEN gas (N2)
BUT we CAN’T use the nitrogen gas
we breathe!
The bond in N2 gas is so
strong it can only be broken by
Lightning
Volcanic Activity
Few Special Bacteria
Image by Riedell
http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm
Image by Riedell
Bacteria that live in the soil
and in symbiotic relationships with
plants called legumes, take
nitrogen from the atmosphere and
turn it into ammonia (NH3), a form
that is usable by plants.
THIS PROCESS
IS CALLED
Nitrogen Fixation
http://www.slic2.wsu.edu:82/hurlbert/micro101/images/101nodules21.gif
Other bacteria in the soil convert
ammonia into Nitrates (NO3)
& Nitrites (NO2)
which plants can also use.
The nitrogen we need for proteins,
ATP, and nucleic acids comes from
the food we eat
Not the air
we breathe!
Image from: http://www.utdallas.edu/images/departments/biology/misc/gonzalez-image.jpg
and http://www.cibike.org/CartoonEating.gif
modified by Riedell
Bacteria that live in the soil
also carry out the reverse process
Nitrates & Nitrites→ Nitrogen Gas N2.
THIS PROCESS
IS CALLED
Denitrification
CARBON CYCLE
•
Air in the atmosphere has carbon in the form of
carbon dioxide gas. Plants ‘breath’ in carbon
dioxide and ‘fix’ it during photosynthesis. They
make sugars, which are energy-rich, carboncontaining compounds (biosphere).
• Organisms break down these sugar molecules
through cellular respiration and release CO2 as
waste (atmosphere).
• When organisms die, their carbon-containing
molecules become part of the soil (lithosphere).
These molecules are broken down by fungi and
other decomposers. During this decay, CO2 is
released into the air (atmosphere)
•
Under certain conditions, the remains of some
dead organisms may be changed into fossil fuels
(Carbon deposit = coal, gas ,oil) (lithosphere)
• Carbon can also dissolve in water – so Oceans
act as Carbon sinks
Humans have affected the cycle
by increasing atmospheric
concentrations:
•
•
Use of Fossil Fuels - increases CO2
Deforestation – reduces fixation
Some impacts = climate change & ocean acidification
WHY IS CARBON IMPORTANT?
Found in all the building blocks of cells:
carbohydrates, proteins,
nucleic acids, lipids
Image by Riedell
http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm
WHY IS CARBON IMPORTANT?
Carbon in CO2 provides the atoms for
glucose production during photosynthesis
the fuel that all living things depend on.
http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0076.JPG
http://www.biologyclass.net/mitochondria.jpg
Homework
If you haven’t done so already, read 1.1, and
answer the following questions:
Pg. 19 Q 5, 6, & 8
Pg. 20 Q 1, 3, 4, & 6
Also, review the diagram of each nutrient cycle and
be able to briefly explain how each nutrient travels
through the 4 spheres: biosphere, atmosphere,
hydrosphere, and lithosphere.
You can expect a test question one day to relate to
one of the cycles!