Carbon Cycle

The carbon cycle is a biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. It is one of the most important cycles in the ecosystem, as carbon is a fundamental building block of all organic life.

Key Processes in the Carbon Cycle

1. Photosynthesis: Plants and other producers absorb atmospheric carbon dioxide ($CO_2$) and convert it into organic compounds (like glucose) using sunlight energy.

   • Equation: $6CO<em>2 + 6H</em>2O + \text{Light Energy} \rightarrow C<em>6H</em>{12}O<em>6 + 6O</em>2$

2. Respiration: Organisms (plants, animals, microbes) release $CO_2$ back into the atmosphere by breaking down organic compounds to obtain energy.

   • Equation: $C<em>6H</em>{12}O<em>6 + 6O</em>2 \rightarrow 6CO<em>2 + 6H</em>2O + \text{Energy}$

3. Decomposition: Decomposers (bacteria and fungi) break down dead organic matter, releasing carbon into the soil and atmosphere as $CO_2$. They are crucial for recycling nutrients.

4. Combustion: The burning of organic matter (like fossil fuels or biomass) releases large amounts of $CO_2$ into the atmosphere. Natural events like forest fires also contribute.

Human Impact on the Carbon Cycle

Human activities, primarily the burning of fossil fuels, deforestation, and industrial processes, have significantly increased the amount of $CO_2$ in the atmosphere, leading to global climate change.

• Ocean Acidification: Increased atmospheric $CO_2$ dissolves in ocean water, leading to the formation of more carbonic acid. This reduces ocean pH, making the water more acidic, which can harm marine life, especially organisms with shells and skeletons.