Chapter 3: Earth’s Environmental Systems Biogeochemical Cycles

Law of Conservation of Mass Matter can not be created or destroyed It just changes form…. Water cycle…changes state Biogeochemical cycles….changes into different compounds through different types of reactions

Nutrients Matter that organisms require for their life processes. Macronutrients vs. Micronutrients Nutrients required in Large amounts like Carbon, Oxygen, Nitrogen and Phosphorus Nutrients required in Small amounts like Potassium, Calcium, Iron, etc.

Producer vs. Consumer Primary producers produce their own food via photosynthesis Plants, algae, phytoplankton (phyto- = plant) Consumers are organisms that must eat (consume) other organisms (plant or animal) to obtain nutrients Mostly animals Decomposers are organisms that break down wastes and dead organisms Bacteria and fungi

Ten Percent Rule

Food chains/Food webs All of the substances that make up an organism is made of carbon…where does it come from? Depends on what type of organism you are….

Carbon Cycle Also includes oxygen Needed for energy Also includes oxygen Carbon is found in most of the compounds on earth…plastic, gasoline, carbohydrates, proteins, lipids, nucleic acids, etc…. A couple things to know in order to understand this cycle…. Food chains/Food webs Producers, Consumers, and Decomposers Photosynthesis Respiration Combustion Decomposition Fossil Fuels Carbon Sinks vs. Carbon sources

Photosynthesis Producers use solar energy to convert CO2 from the air into a usable form of carbon (glucose) that organisms can use for energy (glucose)

Cellular respiration Process by which ALL organisms use oxygen to release the chemical energy of sugars (glucose)

Decomposition All organisms die…where does their carbon go? To the soil and eventually into rock (limestone) or as fossil fuels (coal or petroleum)

Fossil Fuels and Combustion Fossil fuels are used by humans for energy through a process called combustion This releases CO2 back into the atmosphere

Carbon Sinks vs. Carbon Sources Sinks: Holds Carbons Limestone and other sedimentary rock Ocean Plants: Land and Marine (phytoplankton/algae) Permafrost: permanently frozen land Sources: Releases Carbon back to atmosphere Combustion: transportation, industry, etc. Respiration Volcanoes

Phosphorus Cycle Only involves the lithosphere (land) Needed to make DNA and RNA Only involves the lithosphere (land) No atmospheric form Think… Fertilizer Food chains Runoff Eutrophication

Phosphorus is bound up in rocks Low amounts Limiting factor of plant growth Not needed as much as nitrogen…hangs out in water ways Reason why it is main culprit of eutrophication

Eutrophication The effect is an overgrowth of producers (algae) Caused by runoff from fertilizer (high in nitrogen and phosphorus) as well as wastewater (phosphorus is found in detergents) Can lead to hypoxia (low oxygen levels) from bacteria decomposing all the dead producers

Nitrogen Cycle Most abundant gas in atmosphere Needed for proteins Most abundant gas in atmosphere Atmospheric nitrogen is unusable Relies on bacteria to make it usable Think… Fertilizer Legumes Food chains Bacteria: nitrogen fixation Nitrification vs. Denitrofication Lightning Eutrophication

Nitrogen “fixing” Nitrogen fixation: Conversion of nitrogen gas (N2) to ammonia (usable by plants) Lightning Nitrogen-fixing bacteria (found naturally in soil or in root nodules of legumes) Nitrification: bacteria convert ammonia (NH3) into nitrites (NO2) then into nitrates (NO3) Denitrification: denitrifying bacteria convert nitrates back into nitrogen gas (N2)

Secondary Nutrients Potassium Calcium Iron Comes from weathered mineral salts Needed for nerve function Calcium Needed for plant growth and shell formation Iron Needed for photosynthesis and transporting oxygen in blood