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. A biogeochemical cycle is the complete path a chemical takes through the Earth's four major reservoirs:atmospherehydrosphere (oceans, rivers, lakes, groundwaters, and glaciers)lithosphere (rocks and soils)biosphere (plants and animals).. Chemicals enter storage compartments - sinksAmount tha
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1. Chapter 3 Biogeochemical Cycles
2. A biogeochemical cycle is the complete path a chemical takes through the Earth’s four major reservoirs:
atmosphere
hydrosphere (oceans, rivers, lakes, groundwaters, and glaciers)
lithosphere (rocks and soils)
biosphere (plants and animals).
3. Chemicals enter storage compartments - sinks
Amount that moves between compartments is the flux
4. net sink - when input exceeds output
net source - if output exceeds input.
5. Essential Elements 24 elements are required for life
Macronutrients are required in large quantities
carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
Micronutrients are required in small/medium quantities, or not at all in some organisms
Copper, sodium, iodine
6. Geological Cycle The formation and change of Earth materials through physical, chemical, and biological processes
7. The Tectonic Cycle Lithosphere is comprised of several plates floating on denser material
Plates move slowly relative to each other – plate tectonics
8. Divergent plate boundaries occur at spreading ocean ridges
Convergent plate boundaries occur when plates collide
9. Plate movements change the location of continents and alter atmospheric and ocean circulation patterns
Plate boundaries are geologically active, producing volcanoes and earthquakes
10. Hydrologic Cycle Evaporation
Precipitation
Runoff
Groundwater
11. 97% of water is stored in oceans, 2% in glaciers and ice caps, 1% as freshwater on land or atmosphere
Drainage basins or watersheds are the area contributing runoff to a stream or river
Vary in size from a hectare to millions of square miles (e.g. Mississipi River drainage basin)
Human impacts include dam construction, irrigation, stormwater runoff
12. Rock Cycle Igneous rocks form from molten material such as lava. Broken down by physical and chemical weathering
13. Metamorphic rocks are formed from sedimentary rocks exposed to heat, pressure or chemically active fluids
14. Rock Cycle
15. Biogeochemical Cycles in Ecosytems Begins with inputs from reservoirs such as atmosphere, volcanic ash, stream runoff, ocean currents, submarine vents
Chemicals cycle through physical transport and chemical reactions (e.g. decomposition)
All ecosystems “leak” chemicals to other ecosystems.
16. Annual Calcium Cycle in a Forest Ecosystem Soluble in water and easily lost through runoff
17. Annual Sulfur Cycle In a Forest Ecosystem Includes gaseous forms (sulfur dioxide and hydrogen sulfide) and cycles much faster than calcium
18. Carbon Cycle Carbon is vital for life but is not abundant
Enters biological cycles through photosynthesis to produce organic forms of carbon
19. Carbon Cycle in a Pond
20. Large inorganic carbon reservoir in oceans
Dissolved CO2 is converted to carbonate and bicarbonate
Transferred from land by rivers and wind
21. Fossil Fuels Decomposition of dead organisms may be prevented by lack of oxygen or low temperatures
Burial in sediments over thousands or millions of years transforms the stored organic carbon into coal, oil or natural gas
22. Global Carbon Cycle
23. Global Carbon Cycle
25. Case of the missing carbon! Appears oceans are acting as carbon sinks as are forests and grasslands.
But which area is more critical, and which one dominates.
Will these blessings last?
If they stop functioning we could face drastic changes even before 2050.
26. Case of the missing carbon! Global tests of CO2 show less in the north than the south despite larger northern outputs
Why is this the case?
If land plants are doing the work then there should be a corresponding oxygen increase.
If it is dissolving in the oceans then there should be no added oxygen.
27. Case of the missing carbon! Results (best guess):
Ocean is soaking up 2.4 billion tons globally
Land plants do the most work in the northern hemisphere
Forests literally breath in the carbon but appetite changes dramatically due to season, amount of sunlight, rainfall, and age of forests
Marine organisms undergo photosynthesis as well
So that leaves about 2.9 units unaccounted for between these groups.
28. Case of the missing carbon!
29. Nitrogen Cycle Essential for manufacturing proteins and DNA
Although 80% of atmosphere is molecular nitrogen, it is unreactive and cannot be used directly
Nitrogen fixation converts nitrogen to ammonia or nitrate
30. Nitrogen Fixation Some organisms have a symbiotic relationship with nitrogen fixing bacteria
Found in root nodules in some plants, or in the stomach of some herbivores
Nitrogen fixation also occurs through lightning and industrial processes
31. Denitrification When organisms die, denitrifying bacteria convert organic nitrogen to ammonia, nitrate, or molecular nitrogen ..
32. Global Nitrogen Cycle
33. Phosphorus Cycle No gaseous phase
Slow rate of transfer
Released by erosion of exposed rock
Absorbed by plants, algae, and some bacteria
Exported from terrestrial ecosystems by runoff to oceans
May be returned through seabird guano
34. Global Phosphorus Cycle
35. Phosphate Mining Impact on landscape by open-pit mining