Cycles Of Matter WATER CARBON NITROGEN End Show

The Water Cycle HOME

Precipitation Water that has condensed in the air forms clouds. Drops fall to Earth and accumulate in oceans and lakes. Water Cycle

Using Water Plants and animals need water to live. Water is pulled from bodies of water or from the ground (groundwater). The Water Cycle

Transpiration Plants and animals return water to atmosphere through transpiration. Animals return water to ground and bodies of water through urine. The Water Cycle

Evaporation Water from oceans, lakes, and other bodies of water re-enters the atmosphere through evaporation. The Water Cycle

The Carbon Cycle HOME

Back to the Carbon Cycle Photosynthesis Plants use CO2 from the atmosphere, H2O, and radiant energy to make high-energy carbon molecules in the Chloroplasts CO2 + H20  C6H12O6 + O2 Back to the Carbon Cycle

Respiration CO2 is released through aerobic respiration (breathing, for example) This occurs when glucose is converted into cellular energy in the Mitochondria of eukaryotic cells C6H12O6 + O2  CO2 + H2O + energy The Carbon Cycle

Back to the Carbon Cycle Gas Exchange CO2 is exchanged between the air and water Warm water holds more CO2 Back to the Carbon Cycle

Decomposition When organisms die and decay, the carbon molecules in them enter the soil. Microorganisms break down the molecules, releasing CO2 The Carbon Cycle

Back to the Carbon Cycle Pollution Remains of dead organisms are converted into fossil fuels (over millions of years!) Combustion of fossil fuels and wood releases CO2 Back to the Carbon Cycle

The Nitrogen Cycle HOME

Back to the Nitrogen Cycle Nitrogen In the Air Lightning and bacteria convert atmospheric nitrogen into nitrates (NO3) and ammonia (NH3) The air we breathe is about 78% nitrogen in the form of N2 gas and about 21% oxygen in the form of O2 gas. Back to the Nitrogen Cycle

Back to the Nitrogen Cycle Nitrogen in Plants Plants receive their nitrogen through the soil. Nitrogen-fixing bacteria convert the nitrogen in the air and decaying material into nitrogen compounds that plants can utilize. Back to the Nitrogen Cycle

Back to the Nitrogen Cycle Nitrogen in Animals When animals die their decomposing bodies add the nitrogen back into the soil. Animals also add nitrogen to the soil through feces and urine. Animals receive nitrogen from the plants they eat or from other animals that eat plants. Back to the Nitrogen Cycle

Back to the Nitrogen Cycle Return to Atmosphere Nitrogen compounds break down into gas and return to air Back to the Nitrogen Cycle

Nitrogen in Soil and Water Runoff of nitrates in fertilizers enters groundwater and soil. Denitrification is an important step in the nitrogen cycle where nitrogen is released back into the atmosphere. Nitrates are water-soluble and leach out of the soil, flowing into groundwater and collecting in lakes and wetlands. Back to the Nitrogen Cycle

Back to the Nitrogen Cycle Man and Pollution Fertilizers – nitrogen rich molecules made by man to improve the health and productivity of plants Man made pollution such as vehicle exhaust, power-plant exhaust, man made fertilizers and large-animal feeding operations are all sources of nitrogen emissions. Nitrous Oxide from burning fossil fuels falls as Nitric Acid in rainwater Back to the Nitrogen Cycle