1. Biogeochemistry and Biogeochemical Cycles
Definitions:
“…the more or less circular transfer of chemical elements from the (abiotic) environment to the organisms and from organisms back to the (abiotic) environment.” Odum, 1971.
“the study of the controls on the concentrations and cycling of elements in and above the earth’s crust by the synthesis, death and decomposition of organisms.” Gorham, 1991.
Examples:
carbon, nitrogen, sulfur, Fe, Mn, etc.

2. Big Picture
Over the ‘long term’, biogeochemical cycling has played a fundamental role in planetary evolution on Earth (especially the atmosphere and hydrosphere). Example: rise of O2 in Earth’s atmosphere.
At present, many biogeochemical cycles are effectively treated as dynamic equilibria among cycled materials.
Anthropogenic effects are measurable.

4. Orbital Variations Eccentricity 100,000 yr Tilt 41,000 yr
Precession 23,000 yr

14. From Albarede, 2003

15. Residence Time (steady state) Response Time (non steady-state)
Definition: Average time the substance spends in the reservoir. It is the time required to double the concentration in a reservoir (if output ceased).
Ri = amti in reservoir/fluxi Example residence times: water in atmosphere: 11 days water in ocean: 3550 yr
Materials can be imported and exported from ecosystems and long-term storage pools.

19. Basic Biogeochemical Cycle
System boundary
Inorganic Storage Pool
Uplift, mining, etc.
Available Abiotic Pool
Decomposition
(Mineralization)
Living Organic Matter
Biosynthesis
Dead Organic Matter
Death
Organic Storage Pool

21. Major, Minor, and Trace Elements in Biogeochemical Cycles
Major elemental components of living organisms (C, H, O, N, P, S)
Carbohydrates, proteins, lipids, nucleic acids
Minor elements: Ca, K, Mg, Na, Si
Trace elements: B, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, V, Zn, REEs
Ca and Si are only minor components of protoplasm, but are major components of exo and endoskeletons of microorgs and macroorgs
Fe, Mn, N, S are also cycled rapidly via redox processes which may not be directly coupled to the production and decay of organic matter

22. (students run screaming from the room)

24. A Partially Open Biogeochemical Cycle: The Oceanic Carbon System
Atmosphere
CO2
Shallow Sea
Dissolved Inorganic Carbon
EXCHANGE
OF WATER
Organically-Bound Carbon
EXCHANGE
OF WATER
Organic carbon
Carbonate particles
Long-term removal
Deep Sea