The Cycles of Matter Why and how is matter recycled in our ecosystem?
Cycles of Matter • All things in nature are made of matter. Nature recycles matter because matter cannot be created or destroyed. • Matter can only be transformed from one form to another. • Matter remains in nature, cycling from one form to another.
The Carbon Cycle • Carbon is an essential component of all biomolecules, such as protein and fats. • Carbon is also found in carbon dioxide and fossil fuels.
The Carbon Cycle • Carbon dioxide (CO2) is released into the atmosphere through respiration, the burning of fossil fuels and deforestation. • Plants take in carbon dioxide to help make glucose in photosynthesis. • Oxygen is released as an end product. • Consumers eat other organisms to obtain carbon, as well as other nutrients.
The Carbon Cycle • As consumers break down food to obtain energy and nutrition, some of the carbon is released back into the atmosphere as carbon dioxide. • Carbon dioxide is an end product of cellular respiration. • Even plants perform cellular respiration, so plants do release some carbon dioxide back into the atmosphere.
The Carbon Cycle • Sometimes, carbon gets trapped in carbon sinks. These are large reservoirs of carbon. • Carbonates and limestone are good examples.
The Carbon Cycle • Also, dead organisms can be deposited underground, and the carbon in their bodies can form fossil fuels. • What are some examples?
Humans and the Carbon Cycle • Recall that the burning of fossil fuels releases carbon dioxide in the atmosphere. • Many modern technologies rely on these fuels for power.
Humans and the Carbon Cycle • While carbon dioxide remains a trace gas, the amount of CO2 has steadily increased in the past century.
Humans and the Carbon Cycle • Recall that CO2 is a greenhouse gas. While we need CO2 to keep Earth warm, too much CO2 in the atmosphere has the potential to raise temperatures too high. • The increase in absorbed solar energy can possibly cause shifts in global climate patterns – year-to-year weather and precipitation cycles – otherwise known as climate change.
Humans and the Carbon Cycle • Furthermore, the ocean itself serves as a carbon sink. This means that an increase in atmospheric CO2 will raise the level of CO2 in the ocean. • As the ocean’s CO2 levels rise, the pH of ocean water drops, which has the potential to destroy marine ecosystems.
The Nitrogen Cycle • Nitrogen is a key component of our proteins. • Nitrogen makes up 78% of our atmosphere, but we can’t use gaseous nitrogen as a nutrient.
The Nitrogen Cycle • Instead, nitrogen gas (N2) has to be converted to ammonia first. • Special bacteria called nitrogen fixersperform this key role.
The Nitrogen Cycle • Once nitrogen gas has been fixed, the ammonia can be converted to nitrates and nitrites, which are absorbed by plants for nutrition. • Once again, consumers have to eat other organisms to obtain nitrogen.
The Nitrogen Cycle • Decomposers are vital to the health of ecosystems, because they break down dead organisms into organic matter. • Decomposers return nitrogen to the soil, where other plants can absorb it. • Finally, other bacteria can convert some of the soil nitrogen back into nitrogen gas.
The Phosphorus Cycle • Phosphorus is a key molecule in nucleic acids (DNA and RNA). • Phosphorus is readily found in rocks and earth.
The Phosphorus Cycle • Phosphate is released from rock due to weathering, the breakdown of rock. Erosion then transports phosphate into the soil or into water sources. • In either case, phosphate can be absorbed by plants and other producers. Once again, consumers have to eat other organisms for phosphate.
The Phosphorus Cycle • Sometimes phosphate can collect at the bottom of large bodies of water, and form new rock. • Finally, decomposition returns phosphate to the soil, as it does other nutrients.
Humans and the Nitrogen/Phosphorus Cycles • Human farming activities often use fertilizers to stimulate future plant growth. Fertilizers contain additional nitrogen and phosphorus. • However, excessive use of fertilizer can lead to undesired plant growth in other ecosystems via runoff.
Humans and the Nitrogen/Phosphorus Cycles • Algal blooms are rapid and massive growths of algae. Algal blooms are particularly dangerous to local ecosystems, since they can drain vital nutrients from the ecosystem. • Algal blooms often occur when excess nitrogen and phosphorus is dumped into water sources.
Humans and the Nitrogen/Phosphorus Cycles • Also, adding too much nitrogen and phosphorus can lead to oversaturation of the soil. This means that other nutrients are lost, which damages the long-term stability of that ecosystem. • Lastly, plants that adapted to low levels of nitrogen can be put at risk of extinction, as they are not adapted to survive in high-nitrogen ecosystems.