Biogeochemical Cycles

Defined: Movement of water through the atmosphere 75% of the earth is water 99% of water undrinkable (salty & frozen) Water recycles over and over

Water rises into the atmosphere in two ways: – Evaporation: Heat changes water from a liquid to a gas – Transpiration: Water evaporates from the leaves of plants through openings called stomata How does water rise?

Warm, moist air rises and eventually cools – Condensation: process where water vapor turns into a liquid Water in the atmosphere

What goes up….Must come down Precipitation: Rain, snow, sleet, or hail falls when water drops become heavy

Water on the Ground RUNOFF INFILTRATION Runoff: Water runs down hill into rivers, lakes, streams, oceans… Infiltration: Water soaks into the soil and collects as groundwater Process repeats

Oxygen Cycle Autotrophs: Release O 2 into atmosphere via photosynthesis All life: Absorbs O 2 to be used during cellular respiration –R–Respiration: creates ATP energy for cells O2O2 O2O2

Phosphorus (P) Cycle Problem: No phosphorus in atmosphere Phosphorus needed to make ATP, DNA, lipids Step 1: Phosphorus released by weathering of rocks P P

Step 2: Producers absorb P into their roots P P P

Step 2: Producers absorb P into their roots Step 3: Consumers ingest P when plants eaten P P P P P

Phosphorus (P) Cycle P P Step 2: Producers absorb P into their roots Step 3: Consumers ingest P when plants eaten Step 4: Decomposer s breakdown dead matter and release P into soil Cycle repeats P P PP

Phosphorus (P) Cycle Human Contribution – Adding excess P from fertilizers – P washes into lakes, etc… – Excess P causes extreme algae growth P P PP P P

Carbon Cycle Carbon needed to create organic molecules Producers – Intake: Absorb CO 2 from atmosphere during photosynthesis – Output: Release CO 2 during cellular respiration CO 2

Carbon Cycle Consumers – Intake: Carbon moves up the food chain as one feeds on another – Output: Release CO 2 during respiration CO 2 C C

Carbon Cycle Decomposers – Input: Feed on dead organic matter – Output: Organic molecules returned to soil during decomposition C C C

Carbon Cycle Human Contribution – Release CO 2 into atmosphere when fossil fuels (coal, oil, natural gas) are burned for energy CO 2

Nitrogen Cycle Nitrogen needed to build DNA Problem: Nitrogen in atmosphere (78%) is unusable Step 1: Soil Bacteria –N–Nitrogen fixation: convert atmospheric nitrogen into ammonia –N–Nitrification: ammonia converted into nitrates N2N2 Ammonia Nitrates

Nitrogen Cycle Step 2: Producers absorb nitrates through their roots Nitrates

Nitrogen Cycle Step 2: Producers absorb nitrates through their roots Step 3: Consumers ingest nitrates through the food chain Nitrates

Nitrogen Cycle Step 2: Producers absorb nitrates through their roots Step 3: Consumers ingest nitrates through the food chain Step 4: Decomposers return ammonia to soil Cycle repeats Ammonia

Nitrogen Cycle How does lightning help? – Energy breaks atmospheric nitrogen into Nitrogen oxide – Nitrogen oxide falls in rain to soil N2 O2 N N O O NN OO NN OO OO NO

review 1)Name and define the 6 stages of the water cycle. 2)How is oxygen released into the atmosphere? 3)In which cellular process is oxygen removed and used from the atmosphere? 4)Which organic molecule is created by photosynthesis? 5)In which cellular process is carbon dioxide released into the atmosphere? 6)How are humans disrupting the carbon cycle? 7)How does nitrogen fixation and nitrification differ? 8)How do plants obtain nitrogen? 9)Which objects release phosphorus over time? 10)How are humans disrupting the phosphorus cycle?