Carbon cycle

Definition

The carbon cycle is the continuous process by which carbon moves through the Earth’s atmosphere, oceans, soil, and living organisms. This cycle is essential for regulating Earth’s climate and supporting life, as it involves various processes like photosynthesis, respiration, and decomposition that exchange carbon among different reservoirs. Understanding the carbon cycle helps illuminate the human impacts on these natural processes and highlights the interplay between human activities and environmental changes.

5 Must Know Facts For Your Next Test

1. The carbon cycle includes several key processes: photosynthesis by plants absorbs atmospheric carbon dioxide, while respiration by animals releases it back into the atmosphere.
2. Human activities such as burning fossil fuels and deforestation significantly disrupt the natural carbon cycle, leading to increased levels of carbon dioxide in the atmosphere.
3. Carbon can be stored in various forms, including in plants, soil, fossil fuels, and the ocean, where it plays a crucial role in marine ecosystems.
4. The balance of the carbon cycle is essential for maintaining global temperatures; disruptions can lead to climate change and its associated impacts.
5. Ocean acidification occurs when excess atmospheric carbon dioxide is absorbed by oceans, affecting marine life and ecosystems.

Review Questions

• How do photosynthesis and respiration contribute to the carbon cycle?
  • Photosynthesis and respiration are vital processes in the carbon cycle that facilitate the movement of carbon between living organisms and the atmosphere. During photosynthesis, plants take in carbon dioxide from the air and convert it into glucose while releasing oxygen. In contrast, respiration occurs when animals consume this glucose for energy, returning carbon dioxide back to the atmosphere. Together, these processes create a continuous flow of carbon that supports life on Earth.
• Discuss the impact of human activities on the natural carbon cycle and their implications for climate change.
  • Human activities such as burning fossil fuels, deforestation, and industrial processes have greatly altered the natural carbon cycle by increasing greenhouse gas concentrations in the atmosphere. This disruption leads to an enhanced greenhouse effect, resulting in global warming and climate change. The rising levels of atmospheric carbon dioxide contribute to extreme weather events, melting ice caps, and changing ecosystems. Understanding these human impacts emphasizes the need for sustainable practices to restore balance within the carbon cycle.
• Evaluate how changes in ocean chemistry due to increased atmospheric carbon dioxide affect marine ecosystems.
  • Increased atmospheric carbon dioxide leads to higher concentrations of CO2 being absorbed by oceans, resulting in ocean acidification. This change in ocean chemistry has significant consequences for marine ecosystems, particularly for calcifying organisms like corals and shellfish that rely on carbonate ions to build their shells and skeletons. As ocean acidity increases, these organisms struggle to maintain their structures, which can lead to declines in biodiversity and disrupt food webs. The impact of ocean acidification highlights the interconnectedness of human activity with natural systems and stresses the urgency for addressing carbon emissions globally.

Related terms

Photosynthesis: The process by which green plants and some other organisms convert sunlight into chemical energy, using carbon dioxide from the atmosphere and water to produce glucose and oxygen.

Respiration: A metabolic process in which organisms convert glucose and oxygen into energy, releasing carbon dioxide back into the atmosphere.

Greenhouse gases: Gases in the Earth's atmosphere that trap heat, such as carbon dioxide, methane, and nitrous oxide, contributing to global warming.