Applying the Rules to Environmental Science: Biogeochemical Cycles

Earth: Matter does not come and go Earth is a closed system to matter So… matter is constantly recycled on Earth

Biogeochemical Cycles: Reservoirs & Pathways Atmosphere Hydrosphere Lithosphere Biosphere

Some Major Cycles of Matter Water Cycle Rock Cycle Chemical Cycles Carbon Nitrogen Phosphorous Sulfur

Carbon Cycle Atmosphere Hydrosphere Lithosphere Biosphere

Carbon Cycle: Reservoirs Atmosphere Hydrosphere Lithosphere Biosphere 1x (= 7.3x10 17 grams carbon) 3x 55x 35,000x

Carbon Cycle Atmosphere Hydrosphere Lithosphere Biosphere Photosynthesis Respiration& Decay

Carbon Transfer: Biosphere Atmosphere Photosynthesis (Atmosphere to Biosphere) Carbon Dioxide + Water + Sunlight --> Sugar + Oxygen Respiration (Biosphere to Atmosphere) Sugar + Oxygen --> Carbon Dioxide + Water + Energy

Carbon Cycle Atmosphere Hydrosphere Lithosphere Biosphere Photosynthesis Respiration& Decay Burial & Lithification Weathering & Volcanism Dissolution Photosynthesis Burial & Lithification Exsolution

Carbon Cycle Atmosphere Hydrosphere Lithosphere Biosphere Human Impacts Burning fossil fuels: Increased combustion Deforestation: Decrease Photosynthesis Increase Respiration Net Effect: Increase in Carbon in Atmosphere

Atmospheric Carbon Dioxide northern summer northern winter

Impact

Nitrogen Cycle Atmosphere Hydrosphere Lithosphere Biosphere Nitrogen fixation: bacteria lightning Waste & Decomposition Denitification: bacteria Erosion Absorption

Nitrogen- Fixing Bacteria in Root Nodules

Nitrogen Cycle Atmosphere Hydrosphere Lithosphere Biosphere Nitrogen fixation: industrial (fertilizer) combustion Increased Erosion Human Impacts Net Effect: Increase in Nitrogen in water & soil

Phosphorous Cycle Atmosphere Hydrosphere Lithosphere Biosphere Never enters the atmosphere Waste & Decomposition Weathering & Erosion Absorption Sedimentation Absorption

Phosphorous Cycle Hydrosphere Lithosphere Biosphere Mining, use (fertilizer, detergent, etc.) & increased runoff Human Impacts Net Effect: Increase in phosphorous in water & “algal blooms”; Depletion in soils More Phos. for organisms

Impact: Eutrophication

Impact: Red Tide

Sulfur Cycle Atmosphere Hydrosphere Lithosphere Biosphere Volcanoes & Weathering Waste & Decomposition Deep Sea Vents Absorption Sedimentation Absorption Precipitation “Evaporation” Weathering Bacteria Release Bacteria Absorption

Sulfur Cycle Atmosphere Hydrosphere Lithosphere Biosphere Burning Fossil Fuels Precipitation” Acid Rain Human Impacts Net Effect: Increase in atmosphere (health effects) and acid rain

Applying the Rules to Environmental Science: Food Webs

Earth: Earth constantly gains & loses energy Earth is a Open System to Energy Heat Sunlight

“Life is a struggle of an immense number of organisms, weighing next to nothing, for a small amount of energy.”

Producers ( Autotrophs) Tall grass prairie Energy enters the system

Producers Chlorophyll Photosynthesis Carbon Dioxide + Water + Sunlight --> Sugar + Oxygen

Producers Chemosynthesis Hydrogen Sulfide + Carbon Dioxide + Water + Oxygen + Geothermal Heat --> Sugar + Sulfuric Acid

Consumers --> Heterotrophs Primary Consumers - eat producers (Herbivores) Secondary Consumers - eat primary consumers (Carnivores) Tertiary Consumers - eat secondary consumers (Carnivores & Omnivores) Decomposers - break down dead organisms Called “Trophic” (Feeding) Levels Represent the flow of energy (food)

Called “Trophic” (Feeding) Levels Represent the flow of energy (food) Producer Primary Consumer Secondary Consumer Tertiary Consumer Flow of Energy Sun

Forms a Food Chain What happens if… we kill off all the mice?

Food Webs What happens if… we kill off all the crab eater seals? Food webs are more stable than food chains.

Food Webs What happens if… we kill off all the crab eater seals? Food webs are more stable than food chains.

Lessons 1.Food webs are more stable than food chains 2.The produces are the key to the entire food web 3.Life is rough at the top

Energy & “Trophic” Levels Producer Primary Consumer Secondary Consumer Tertiary Consumer Flow of Energy Sun 2nd Law of Thermodynamics Energy is lost during conversion About 90% loss each step 1000 units 100 units 10 units 1 units 900 lost 90 lost 9 lost

“Energy Units” Measured as Biomass Producers Primary Consumers Secondary Consumers Tertiary ConsumersShown as a Trophic Pyramid

“Energy Units” Measured as Biomass Producers Primary Consumers Secondary Consumers Tertiary Consumers Energy captured and turned into biomass by all producers is called Net Primary Productivity

For example:

Why does diet mater? If each person required 10 g/m 2 food per day: This ecosystem could feed: 80 people on plants 4 people on herbivores 1 person on all carnivores

Applying the Rules to Environmental Science: Bioconcentration

Bioconcentration up the Trophic Pyramid Energy degrades…but matter does not Toxin (e.g. heavy metals)

Example: DDT High concentrations of DDT weakens egg shells in fish- eating birds & chicks die