Unit 1 APES

• Humans combusting fossil fuels is the way that we create synthetic nitrate-based fertilizers
• Plants can't assimilate nitrogen or take it into their bodies if it's not in a solid fixed form like ammonia or nitrate
• Nitrogen fixation


  Most important step in the nitrogen cycle
• The phosphorus cycle does not have a gas phase, so phosphorus is cycling much more slowly than the other three forms of matter
• Phosphorus reservoirs


  • Rocks and sediments that contain phosphorus based minerals
• Weathering


  Breakdown of rocks by processes like wind, rain, freezing and thawing
• Erosion


  Phosphorus and sediments being carried from one place to another
• Phosphorus is often a limiting nutrient in both aquatic and terrestrial ecosystems
• Hydrologic cycle


  The water cycle, driven by energy from the sun
• Evaporation


  Water converting from liquid to gas phase due to energy from the sun
• Condensation


  Moisture in air reaching a condensation point based on temperature
• Infiltration


  Precipitation or surface water seeping into or sinking through soil into groundwater
• Transpiration


  Water leaving stomata in leaves and entering atmosphere as gas
• The world's largest freshwater reservoirs (polar ice caps and glaciers) are the least accessible
• Primary productivity


  The rate of photosynthesis in a given area
• Gross primary productivity


  The total amount of energy that plants produce
• Net primary productivity


  The amount of energy that plants can actually store after respiration loss
• Trophic pyramid


  • Represents the flow of energy through an ecosystem from producers to consumers
• Each trophic level only receives 10% of the energy from the level below due to energy losses
• 10 rule


  Primary consumers receive 10% of energy from producers, secondary consumers receive 1%, and tertiary consumers receive 0.1%
• Food web/chain


  Arrows show the movement of energy and matter between organisms
• Removal of a top predator can have trophic cascade effects, impacting the entire food web
• Nitrogen fixation

  The process by which atmospheric nitrogen is converted into a solid fixed form, such as ammonia or nitrate, that plants can assimilate and use for growth.
• Ammonia

  A solid fixed form of nitrogen (NH3) that plants can assimilate and use for growth.
• Nitrate

  A solid fixed form of nitrogen (NO3-) that plants can assimilate and use for growth.
• Microorganisms

  Bacteria and other microscopic organisms that live in the soil and convert atmospheric nitrogen into solid fixed forms that plants can assimilate.
• Assimilation

  The process by which plants take up and use nutrients, such as nitrogen, for growth and development.