1. Biogeochemical Cycles
Chapter 3

2. Key Terms Leaching Limiting Nutrient Urbanization Percolation
Loss of water soluble nutrients from the soil, due to rain, irrigation, etc..
Limiting Nutrient
Plant's growth is often directly related to the amount of whichever limiting nutrient (nitrogen or phosphorus) that it is are able to get. Generally speaking, phosphorus is a limiting nutrient in freshwater systems and nitrogen is a limiting nutrient in saltwater systems.
Urbanization
Taking on the characteristics of a city or town (rural to urban)
Percolation
Movement of fluid through the soil

3. Hydrologic Cycle
Water allows essential molecules to move within and between cells, draws nutrients into the leaves of trees, dissolves and removes toxic materials, and performs many other critical biological functions.
“universal solvent”
Anthropogenic
Deforestation, urbanization, percolation reduction, increase runoff, mining of fossil fuels (oil spills), and water diversion
System Terms
Evaporation, condensation, precipitation, transpiration, evapotranspiration, infiltration, and runoff

4. Carbon Cycle Good at bonding
Most important element in living organisms.
Located in the atmosphere and ground
Six processes that drive the carbon cycle
Photosynthesis (remove carbon)
Respiration (release carbon)
Oceanic absorbition, photosynthesis and respiration (remove and release carbon)
Sedimentation (limestone)/burial (fossil fuels/lock carbon out)
Combustion (burning fossil fuels releases carbon)
Anthropogenic
Burning fossil fuels and deforestation (global warming)

5. Nitrogen Cycle Amino acids (to build proteins)
Limiting nutrient for producers
78% N2 in the atmosphere (unusable for plants and animals)
Series of steps:
Nitrogen fixation (bacteria (cyanobacteria), bacteria in legumes, lightning, combustion, burning of fossil fuels, and humans
Nitrogen to ammonium or nitrates (usable for producers)
Assimilation
Producers absorb and use the ammonium or nitrates. Consumers assimilate nitrogen by eating producers.
Ammonification
Fungal and bacteria decomposers take waste and dead tissue and break it down to ammonium.
Nitrification
Bacterial converts ammonium into nitrites and then into nitrates (NO31-).
Denitrification
Bacteria converts nitrates back to nitrogen
Anthropogenic (fertilizers runoff-algal blooms, eutrophication, then dead zones)
Leaching occurs

6. Phosphorus Cycle Nuclear material (DNA, RNA, ATP, and lipids)
Limiting nutrient – second to nitrogen in its importance
No gaseous component
Not very soluble in water – precipitates out forming phosphates
Usable as a phosphate (PO43-)
Found in rock (weathering) and decomposed vegetation
Anthropogenic
Detergents/fertilizers (mining)
Algal blooms-eutrophication-hypoxic conditions (dead zones)
Mississippi river empting into the Gulf of Mexico
Florida everglades – phosphates changed the ecosystem

7. Calcium, Magnesium, Potassium, and Sulfur
Regulation of cellular respiration and transmitting signals between cells
Rock and decomposed vegetation
Magnesium (Mg2+) and Calcium (Ca2+)
Strong attraction to soil (soil is negative charged/magnesium and calcium are positive charged)
Potassium (K+)
Less attraction/leach away by water
Sulfur
Component of proteins/allowing organisms to use oxygen
Usable as a sulfate (SO42-)
Weathering of rocks and volcanic eruption
Anthropogenic
Burning fossil fuels and mining
Acid precipitation (H2SO4)