Monthly Follow-Up Session #1 Ecosystems: Interactions, Energy and Dynamics Kelly Orlando

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)

Evolution of Photosynthesis in Earth’s History Billions of Years Ago Formation of EarthFirst photosynthetic bacteriaCyanobacteriaFirst rock evidence of atmospheric oxygenRed and brown algaeGreen algaeFirst land plantsVascular plants Humans

Modified from Introduction to Atmospheric Chemistry, P. Hobbs, 2000 Effects of photosynthesis on Earth’s atmosphere

How does Photosynthesis effect biogeochemistry cycling on Earth? Carbon cycle Oxygen cycle Nitrogen cycle

Oxygen Cycle Sources of oxygen: – Chemical breakdown of water in the upper atmosphere – Photosynthesis UV radiation can convert some O 2 to O 3 (ozone)

Carbon Cycle Carbon fixation through photosynthesis Release of carbon through respiration Decomposers recycle carbon back into atmosphere

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 boniferous-period-the-age-of-coal

Nitrogen cycle Atmosphere is reservoir of nitrogen (~80%) Biological nitrogen fixation converts gaseous N 2 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) 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 – H 2 S and SO 2 in atmosphere – Decaying matter returns sulfur to soil, bacteria perform anaerobic respiration to produce H 2 S 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… shed/find_your_watershed shed/find_your_watershed _for_you _for_you Chester County Maps Maps

How you and your students can help… al=PA al=PA Example: Tools: –

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 over- farming, 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)

Bioaccumulation Other substances: mercury, lead, polychlorinated biphenyls (PCBs)

Bioaccumulation Activity jan/11C_bioaccumulation.pdf jan/11C_bioaccumulation.pdf

Discussion: How could you incorporate this information into your classroom? – Lesson? – Activity? – Field trip?