Monthly Follow-Up
Session #1
Ecosystems: Interactions, Energy and
Dynamics
Kelly Orlando
korlando1@immaculata.edu
Movement of materials through
ecosystems
• Biogeochemical cycles
– Cyclic flow of nutrients through an ecosystem
– Abiotic and biotic factors
– Two compartments:
• Reservoir compartment (larger compartment, material
largely unavailable to living organisms)
• Exchange compartment (smaller compartment, usually
active and available to living organisms)
Types of Biogeochemical cycles:
• Gaseous
• Sedimentary
Gaseous Cycles
• Major reservoir: atmosphere
• Global in scale
• (ex) oxygen, carbon, nitrogen, water vapor
(hydrological cycle)
5
4.5
4
3.5
3
2.5
2
Billions of Years Ago
1.5
1
0.5
Humans
First land plants
Vascular plants
Green algae
Red and brown algae
First rock evidence of atmospheric oxygen
Cyanobacteria
First photosynthetic bacteria
Formation of Earth
Evolution of Photosynthesis in Earth’s
History
0
Effects of photosynthesis on Earth’s atmosphere
100
O2
105
10
104
1
103
CO2
0.1
102
101
0.01
4
3
2
1
0.8
0.6
0.4
0.3
Billions of Years before Present
Modified from Introduction to Atmospheric Chemistry, P. Hobbs, 2000
0.2
0.1
Ground-level O2 Concentration (%PAL)
Ground-level CO2 Concentration (%PAL)
106
How does Photosynthesis effect
biogeochemistry cycling on Earth?
• Carbon cycle
• Oxygen cycle
• Nitrogen cycle
http://telstar.ote.cmu.edu/environ/m3/s4/graphics/embedded/cycleoxygentest.png
Oxygen Cycle
• Sources of
oxygen:
– Chemical
breakdown of
water in the
upper
atmosphere
– Photosynthesis
• UV radiation
can convert
some O2 to O3
(ozone)
http://telstar.ote.cmu.edu/environ/m3/s4/graphics/embedded/cycleoxygentest.png
Carbon Cycle
• Carbon fixation
through
photosynthesis
• Release of
carbon through
respiration
• Decomposers
recycle carbon
back into
atmosphere
http://scied.ucar.edu/carbon-cycle
Carboniferous Period
• Around 300 million
years ago
• Accumulation of
organic matter
• Time, pressure and
temperature
converted them to
fossil fuels
• Should be in reservoir
• Large scale human
extraction
http://www.geocaching.com/geocache/GC1BJ3J_car
boniferous-period-the-age-of-coal
Nitrogen cycle
• Atmosphere is reservoir
of nitrogen (~80%)
• Biological nitrogen
fixation converts
gaseous N2 to ammonia
• Ammonification
(degrade proteins into
ammonia)
• Nitrification (conversion
to form that plants can
use, but can be leached
out of soil)
• Denitrification (return
nitrogen to atmosphere)
http://www.epa.gov/caddis/ssr_amm_nitroge
n_cycle_popup.html
Hydrological (Water) Cycle
Sedimentary Cycles
• Major reservoirs are in rocks and minerals in
earth’s crust
• Salts
• Sulfur
– Storage in soil and sediments
– H2S and SO2 in atmosphere
– Decaying matter returns sulfur to soil, bacteria
perform anaerobic respiration to produce H2S
• Phosphorous
– Not present in atmosphere
Phosphorous Cycle
• Major
reservoir:
rocks,
released by
weathering
• Causes
boost in
algal growth
Activity: Pollution Investigation Lab
• Form groups
• Perform lab, complete lab handout
• Search online:
– Look up info on each pollutant: danger to
environment/humans, acceptable levels of
pollutant. Discuss with rest of class.
To find out more about your
watershed…
• http://phillywatersheds.org
• http://www.phillywatersheds.org/your_water
shed/find_your_watershed
• http://www.phillywatersheds.org/whats_in_it
_for_you
• Chester County
• http://www.chesco.org/2187/WatershedsMaps
How you and your students can help…
• http://cfpub.epa.gov/surf/state.cfm?statepost
al=PA
• Example:
• http://www.wvwa.org/volunteering/
• Tools:
– http://www.vernier.com/water-quality/
Human Impact
• Burning fossil fuels releases excess carbon into
atmosphere
• Acid rain- pollutants from coal power plants and
vehicles combine with water vapor form acids
• Concentration of livestock waste
– Anaerobic bacteria increase nutrient recycling
• Removal of reservoirs through mining and overfarming, deforestation, desertification
• Adding nitrogen and phosphorus (agricultural
runoff/sewage) to aquatic runoff depletes dissolved
oxygen, can kill aquatic organisms (denitrifying bacteria
can’t keep up)
• Excess nitrogen and phosphorous algal blooms
algae die Dead Zones
Dead Zone in the Gulf of Mexico
• Largest
recurring
hypoxic zone in
US
• Mississippi
River is
drainage for
41% of
continental US
• 1.7 million tons
of phosphorous
and nitrogen
every year
Heavy Metals, Pesticides and Toxins
• Biological magnification/Bioaccumulation
– Accumulation of non-biodegradable substances
through an ecosystem
– Fat-soluble compounds, larger effect on high level
consumers (top of food chain)
http://www.fws.gov/contaminants/info/ddt.html
Bioaccumulation
• Other substances: mercury, lead,
polychlorinated biphenyls (PCBs)
Bioaccumulation Activity
• http://stao.ca/res2/mags/2013jan/11C_bioaccumulation.pdf
Discussion:
• How could you incorporate this information
into your classroom?
– Lesson?
– Activity?
– Field trip?