Biogeochemical Cycles Chapter – 37.20

What you need to know! The water, carbon, nitrogen, and phosphorus chemical cycles The water, carbon, nitrogen, and phosphorus chemical cycles The various abiotic reservoirs for each cycle The various abiotic reservoirs for each cycle

Nutrients Recycle Biogeochemical cycles are the interactions between biotic and abiotic factors that account for the recycling of nutrients in an ecosystem Biogeochemical cycles are the interactions between biotic and abiotic factors that account for the recycling of nutrients in an ecosystem All four major cycles share a pattern: All four major cycles share a pattern: Nutrients are stored in an Nutrients are stored in an abiotic reservoir Nutrients move through the Nutrients move through the food web Detritivores decompose Detritivores decompose everything back to the reservoir

The Water Cycle

Water Cycle 1. Evaporation & transpiration (from plants) accounts for all the water in the atmosphere. 2. Water forms clouds (condensation), and then rains (precipitation) back down to the Earth. 3. Water runs into streams and rivers (runoff) or is absorbed into the ground (seepage) to become ground water. 4. Water is taken up by the roots of plants or it makes its way to the oceans, flowing above ground or below ground. Abiotic Reservoir = Oceans, Lakes, & atmosphere Abiotic Reservoir = Oceans, Lakes, & atmosphere

The Carbon Cycle

Carbon Cycle Photosynthesis, cellular respiration, and decomposition take up and release Carbon and Oxygen. Photosynthesis, cellular respiration, and decomposition take up and release Carbon and Oxygen. Volcanic eruptions and erosion release Carbon Dioxide into the atmosphere and oceans Volcanic eruptions and erosion release Carbon Dioxide into the atmosphere and oceans Burial and decomposition of dead organisms store Carbon underground (coal & oil). Burial and decomposition of dead organisms store Carbon underground (coal & oil). Human activities, such as cutting and burning forests, and burning fossil fuels, release Carbon Dioxide into the atmosphere. Human activities, such as cutting and burning forests, and burning fossil fuels, release Carbon Dioxide into the atmosphere. Climate change (global warming) Climate change (global warming) Abiotic Reservoir = atmosphere & fossil fuels Abiotic Reservoir = atmosphere & fossil fuels

The Nitrogen Cycle

Nitrogen Cycle Nitrogen Fixation changes the nitrogen in the air into nitrogen that plants can use in the soil (nitrate ions & ammonium ions). Nitrogen Fixation changes the nitrogen in the air into nitrogen that plants can use in the soil (nitrate ions & ammonium ions). Lightning, bacteria, fertilizer Lightning, bacteria, fertilizer Once Nitrogen has been fixed in the soil it is then taken up by the roots of plants (producers). Once Nitrogen has been fixed in the soil it is then taken up by the roots of plants (producers). Abiotic Reservoir = atmosphere Abiotic Reservoir = atmosphere

The Phosphorus Cycle

Phosphorus Cycle It is not abundant in the atmosphere, so it follows a simple cycle. It is not abundant in the atmosphere, so it follows a simple cycle. soil  producer  herbivore  carnivore  decomposer  back to soil soil  producer  herbivore  carnivore  decomposer  back to soil Abiotic reservoir = rocks Abiotic reservoir = rocks

Human Disturbance Human alteration of habitats can impact multiple ecosystems Human alteration of habitats can impact multiple ecosystemsExample: When forests are cut down there are fewer plants to absorb essential nutrients in the soil When forests are cut down there are fewer plants to absorb essential nutrients in the soil Water washes the nutrients away to other ecosystems Water washes the nutrients away to other ecosystems These other These other ecosystems are also altered