Carbon cycle

Definition

The carbon cycle is the series of processes through which carbon atoms circulate in the Earth's systems, including the atmosphere, biosphere, hydrosphere, and geosphere. This cycle plays a crucial role in regulating Earth’s climate, supporting life, and maintaining ecological balance by involving various reservoirs and fluxes of carbon across different spheres.

5 Must Know Facts For Your Next Test

1. The carbon cycle involves key processes like photosynthesis, respiration, decomposition, and combustion, which transfer carbon among different reservoirs.
2. Carbon is stored in various reservoirs including the atmosphere (as CO2), terrestrial biomass (plants and animals), oceans (dissolved CO2), and fossil fuels.
3. Human activities like deforestation and burning fossil fuels significantly disrupt the natural carbon cycle by increasing atmospheric CO2 levels.
4. The ocean plays a critical role in the carbon cycle by absorbing a large amount of CO2 from the atmosphere, which can lead to ocean acidification.
5. The carbon cycle influences climate change through the greenhouse effect, where increased levels of CO2 contribute to global warming.

Review Questions

• How do photosynthesis and respiration interact within the carbon cycle to maintain ecological balance?
  • Photosynthesis and respiration are interconnected processes within the carbon cycle that help maintain ecological balance. During photosynthesis, plants absorb carbon dioxide from the atmosphere and convert it into organic matter while releasing oxygen. In contrast, respiration occurs when living organisms consume oxygen to break down glucose for energy, releasing carbon dioxide back into the atmosphere. This reciprocal relationship ensures that carbon is cycled efficiently through ecosystems, supporting both plant growth and energy production for animals.
• Discuss how human activities have altered the natural carbon cycle and what implications this has for climate change.
  • Human activities such as deforestation, industrial processes, and fossil fuel combustion have significantly altered the natural carbon cycle. These actions release excessive amounts of carbon dioxide into the atmosphere, enhancing the greenhouse effect and contributing to global warming. The disruption of the balance between carbon emissions and natural absorption mechanisms leads to elevated atmospheric CO2 levels, resulting in climatic shifts that can affect ecosystems, weather patterns, and sea levels worldwide.
• Evaluate the role of oceanic processes in the carbon cycle and their impact on global biogeochemical dynamics.
  • Oceanic processes are crucial in regulating the carbon cycle as they act as significant carbon sinks. The oceans absorb about 30% of atmospheric CO2 through physical diffusion and biological processes like photosynthesis by phytoplankton. However, increased CO2 absorption leads to ocean acidification, which impacts marine life and disrupts food webs. Evaluating these dynamics highlights the interconnectedness of global biogeochemical cycles and stresses the importance of protecting marine ecosystems in mitigating climate change impacts.

Related terms

photosynthesis: The process by which green plants and some other organisms convert light energy into chemical energy by using carbon dioxide and water to produce glucose and oxygen.

respiration: The metabolic process in which living organisms convert oxygen and glucose into energy, releasing carbon dioxide and water as byproducts.

fossil fuels: Natural substances formed from the remains of ancient organisms that are rich in carbon, such as coal, oil, and natural gas, and are used as energy sources.