Cycling of Matter

Recap: Environment: all abiotic and biotic factors that exist on Earth as well as their interactions Abiotic: non-living factors Biotic: living factors Biodiversity: # of diff. organisms in an area -increase biodiversity, increase healthy, sustainable envmt Parts of an ecosystem can be organized as follows: spp  pop’n  community  ecosytem  biome

What Sustains Life on Earth? Solar energy, the cycling of matter, and gravity sustain the earth’s life.

Two Secrets of Survival: Energy Flow and Matter Recycle An ecosystem survives by a combination of energy flow and matter recycling.

Key Terms Organic substances: contain atoms of C, H, and many times O, N (e.g.) proteins, sugars, fats (generally associated with living things) Inorganic substances: matter does not contain a combination of C and H atoms (e.g.) nylon, carbon dioxide (non-living forms) organic consumption decay inorganic Decay: organic materials die, and then decomposers break them down and recycle nutrients back to the earth Decomposers: (mushrooms, bread mold, bacteria, fungi) break down organic matter into small inorganic molecules

MATTER CYCLING IN ECOSYSTEMS Nutrient Cycles: Global Recycling  Cycles recycle nutrients through the earth’s air, land, water, and living organisms.  Nutrients are the elements and compounds that organisms need to live, grow, and reproduce.  Cycles move these substances through air, water, soil, rock and living organisms.

Cycles: Reservoirs & Pathways Atmosphere Hydrosphere Lithosphere Biosphere

The Water Cycle Water is moved throughout the entire hydrosphere. It moves in a cycle, which means it has no beginning or end. Key terms: evaporation – water droplets changing from a liquid to a gas condensation – water droplets changing from a gas to a liquid precipitation – water falling from the atmosphere transpiration – plants release water into atmosphere via their leaves seepage – water that flows into large underground lakes

Precipitation Transpiration Condensation Evaporation Ocean storage Transpiration from plants Precipitation to land Groundwater movement (slow) Evaporation from land Evaporation from ocean Precipitation to ocean Infiltration and Percolation Rain clouds Runof f Surface runoff (rapid)

Effects of Human Activities on Water Cycle We alter the water cycle by:  Withdrawing large amounts of freshwater.  Clearing vegetation and eroding soils.  Polluting surface and underground water.  Contributing to climate change.

Carbon Cycle Atmosphere Hydrosphere Lithosphere Biosphere

C cycles between living and non-living forms Inorganic (non-living) CO 2 in atmosphere (carbon dioxide) C in rocks C dissolved in oceans Organic (in living things) Sugar (C 6 H 12 O 6 ) Fats, Proteins, DNA Respiration Photosynthesis

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 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

Carbon Cycle Carbon is vital for life but is not abundant Enters biological cycles through photosynthesis to produce organic forms of carbon Carbon is moved back into the inorganic form through cellular respiration ( which is the opposite of photosynthesis )

Photosynthesis Carbon dioxide + water → sugar + oxygen + ENERGY Chlorophyll CO 2 + H 2 O + Energy → C 6 H 12 O 6 + O 2

Respiration + ENERGY Sugar + oxygen → carbon dioxide + water C 6 H 12 O 6 + O 2 → CO 2 + H 2 O + Energy Mitochondria

Combustion Makes carbon dioxide from… organic matter

Effects of Human Activities on Carbon Cycle We alter the carbon cycle by adding excess CO 2 to the atmosphere through:  Burning fossil fuels.  Digging up fossil fuels/ coal.  Clearing vegetation faster than it is replaced.  Breathing out also releases carbon dioxide!

THE NITROGEN CYCLE Another Nutrient

Nitrogen Cycle Essential for manufacturing proteins and DNA Although 80% of atmosphere is molecular nitrogen, it is unreactive and cannot be used directly Nitrogen fixation converts nitrogen to ammonia or nitrate Nitrates are the usable form of nitrogen (plants use this)

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

Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by:  Adding gases that contribute to acid rain.  Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone.  Contaminating ground water from nitrate ions in inorganic fertilizers.  Releasing nitrogen into the troposphere through deforestation.

Effects of Human Activities on the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined. Figure 3-30

P 27 #1-4, P29 #1-4 Textbook Practice Questions