Carbon cycle

Definition

The carbon cycle is the continuous process through which carbon is exchanged among the Earth's atmosphere, land, ocean, and living organisms. This cycle plays a crucial role in regulating the Earth's climate, supporting life through photosynthesis, and maintaining the balance of carbon in various spheres of the planet.

5 Must Know Facts For Your Next Test

1. Carbon dioxide is absorbed by plants during photosynthesis, which forms the basis of the food web and supports life on Earth.
2. The ocean acts as a major carbon sink, absorbing large amounts of CO2 from the atmosphere and helping to regulate global temperatures.
3. Human activities like burning fossil fuels and deforestation are significantly altering the carbon cycle, leading to increased greenhouse gas concentrations in the atmosphere.
4. Carbon is stored in various reservoirs, including forests, soil, oceans, and the atmosphere, and its movement between these reservoirs can take years to millennia.
5. Natural processes like volcanic eruptions release stored carbon back into the atmosphere, contributing to the dynamic nature of the carbon cycle.

Review Questions

• How do processes like photosynthesis and respiration contribute to the movement of carbon within the carbon cycle?
  • Photosynthesis and respiration are key processes that facilitate the movement of carbon within the carbon cycle. During photosynthesis, plants absorb carbon dioxide from the atmosphere to produce glucose, storing carbon in their tissues. Conversely, respiration occurs when organisms convert glucose back into energy, releasing carbon dioxide into the atmosphere. This back-and-forth exchange ensures that carbon continuously cycles through living organisms and the environment.
• Evaluate how human alterations to the carbon cycle can impact climate regulation and global temperatures.
  • Human activities, particularly the burning of fossil fuels and deforestation, have drastically altered the natural carbon cycle. These actions increase the concentration of greenhouse gases in the atmosphere, which enhances the greenhouse effect and contributes to global warming. The resulting climate change can lead to severe weather events, rising sea levels, and disruptions to ecosystems. Thus, understanding these impacts is critical for developing strategies to mitigate climate change.
• Analyze the interconnectedness of Earth's spheres as illustrated by the carbon cycle and its role in maintaining environmental balance.
  • The carbon cycle exemplifies the interconnectedness of Earth's spheres—atmosphere, biosphere, hydrosphere, and lithosphere—by demonstrating how carbon flows between them. Carbon dioxide from the atmosphere is absorbed by oceans and plants (biosphere), while decomposed organic matter contributes to soil carbon storage (lithosphere). This intricate network ensures that vital processes like photosynthesis occur while maintaining climate stability. Understanding these interactions helps clarify how disruptions in one sphere can have cascading effects on others.

Related terms

Photosynthesis: The process by which green plants and some other organisms use sunlight to synthesize foods with the help of carbon dioxide and water.

Respiration:

A metabolic process in which living organisms convert oxygen and glucose into energy, releasing carbon dioxide as a byproduct.

Fossil Fuels: Natural substances such as coal, oil, and natural gas formed from the remains of ancient plants and animals, which release carbon into the atmosphere when burned.