Biogeochemical Cycles

Cycling of Matter

  • Explain how energy flows and matter cycles through trophic levels.

  • All ecosystems depend on a continuous inflow of high-quality energy in order to maintain their structure and function of transferring matter between the environment and organisms via biogeochemical cycles.

  • Biogeochemical cycles are essential for life and each cycle demonstrates the conservation of matter.

  • In terrestrial and near-surface marine communities, energy flows from the sun to producers in the lowest trophic levels and then upward to higher trophic levels.

    • What are the different levels of the trophic pyramid (producers, primary consumers/herbivores, secondary consumers/carnivores, tertiary consumers, and/or apex predators)?

    • What is the biomass difference between trophic levels?

    • What is the 10% rule? Why is it important?

Carbon Cycle

  • Explain the steps and reservoir interactions in the carbon cycle.

  • The carbon cycle is the movement of atoms and molecules containing the element carbon between sources and sinks.

  • Some of the reservoirs in which carbon compounds occur in the carbon cycle hold those compounds for long periods of time, while some hold them for relatively short periods of time.

  • Carbon cycles between photosynthesis and cellular respiration in living things.

  • Plant and animal decomposition have led to the storage of carbon over millions of years. The burning of fossil fuels quickly moves that stored carbon into atmospheric carbon, in the form of carbon dioxide.

  • Urbanization, through the burning of fossil fuels and landfills, affects the carbon cycle by increasing the amount of carbon dioxide in the atmosphere.

    • You should be able to draw a basic carbon cycle.

    • What are some human impacts on the carbon cycle?

    • How does deforestation affect the carbon cycle?

    • What are the reservoirs in the carbon cycle (oceans, forests....any others?)

    • Know the equation for photosynthesis and cellular respiration (HINT: memorize one. The other is the exact opposite.)

    • How are fossil fuels formed (basics....we will get into the details later)?

    • How does the usage of fossil fuels affect the carbon cycle?

    • What is the difference between using a fossil fuel for energy and biomass (recently dead organisms) for energy?

    • What the LARGEST contributor to carbon dioxide in the atmosphere?

    • Which greenhouse gases have carbon (CO, CO2 and CH4.....any others?)

Nitrogen Cycle

  • Explain the steps and reservoir interactions in the nitrogen cycle.

  • The nitrogen cycle is the movement of atoms and molecules containing the element nitrogen between sources and sinks.

  • Most of the reservoirs in which nitrogen compounds occur in the nitrogen cycle hold those compounds for relatively short periods of time.

  • Nitrogen fixation is the process in which atmospheric nitrogen is converted into a form of nitrogen (primarily ammonia) that is available for uptake by plants and that can be synthesized into plant tissue.

  • The atmosphere is the major reservoir of nitrogen.

    • You should be able to draw a basic nitrogen cycle.

    • What are some human impacts on the nitrogen cycle?

    • What are the reservoirs in the nitrogen cycle (the atmosphere is one....any others?)

    • Know the difference between ammonification, nitrogen fixation, nitrification, and denitrification. Which of these converts inorganic nitrogen to a form living things can use?

Phosphorous Cycle

  • Explain the steps and reservoir interactions in the phosphorus cycle.

  • The phosphorus cycle is the movement of atoms and molecules containing the element phosphorus between sources and sinks.

  • The major reservoirs of phosphorus in the phosphorus cycle are rock and sediments that contain phosphorus-bearing minerals.

  • There is no atmospheric component in the phosphorus cycle, and the limitations this imposes on the return of phosphorus from the ocean to land make phosphorus naturally scarce in aquatic and many terrestrial ecosystems. In undisturbed ecosystems, phosphorus is the limiting factor in biological systems.

    • You should be able to draw a basic phosphorous cycle.

    • What are some human impacts on the phosphorous cycle?

    • What are the reservoirs in the phosphorous cycle?

    • What is the BIGGEST difference between the phosphorous cycle and all of the other cycles we talk about in this course?

    • What is the limiting factor in MOST natural systems?

    • What is the primary ingredient in MANY fertilizers?

    • What happens when a previously limiting factor is added to an ecosystem?

Sulfur Cycle

  • Most sulfur is located in rocks and ocean sediments. Some is found in the atmosphere.

  • Weathering, volcanic eruptions, and the decay of dead organisms naturally release sulfur into the environment.

  • Sulfur is released into the atmosphere as SOx when fossil fuels, specifically coal and oil, are burned

  • Current sulfur production exceeds sulfur consumption as the production of recovered sulfur has increased around the world as a result of environmental awareness. Modern sulfur production results in improved environmental conditions compared to other mineral production.

    • The sulfur cycle has been decreasing in importance on the AP exam in recent years. However, you should still know about it.

    • You should be able to draw a basic sulfur cycle.

    • What are some human impacts on the sulfur cycle?

    • What are the reservoirs in the sulfur cycle?

    • How is sulfur released into the atmosphere NATURALLY?

    • How is sulfur released into the atmosphere by HUMANS?

    • What happens when SOx combines with H2O in the atmosphere?

    • Why is this a problem?

Oxygen Cycle

  • Explain the importance of stratospheric ozone to life on Earth.

  • The stratospheric ozone layer is important to the evolution of life on Earth and the continued health and survival of life on Earth.

    • There are two types of ozone - stratospheric and tropospheric. Know how both are formed.

    • Which one do we NEED for life on Earth? Which one is a pollutant?

    • Why do we need the ozone layer?

Hydrologic/Water Cycle

  • Explain the steps and reservoir interactions in the hydrologic cycle.

  • The hydrologic cycle, which is powered by the sun, is the movement of water in its various solid, liquid, and gaseous phases between sources and sinks.

  • The oceans are the primary reservoir of water at the Earth’s surface, with ice caps and groundwater acting as much smaller reservoirs.

  • Urbanization can lead to depletion of resources and saltwater intrusion in the hydrologic cycle.

    • You should be able to draw a basic water cycle.

    • What are some human impacts on the water cycle?

    • What are the reservoirs in the water cycle?

    • What are the three phases of water?

    • What is so important (environmentally) about the fact that solid water floats?

    • Why is the fact that water has a high specific heat important?

    • Where is most of the water on Earth? Can we drink it?