Which earth system is the smallest carbon reservoir? A. The atmosphere B. The Biosphere C. The Geosphere D. The Hydrosphere
The Correct Answer and Explanation is:
The correct answer is A. The atmosphere.
Explanation:
In terms of carbon reservoirs, the atmosphere is the smallest of the Earth’s systems. The four main Earth systems—atmosphere, biosphere, geosphere, and hydrosphere—each contain varying amounts of carbon.
- Atmosphere: The atmosphere contains carbon primarily in the form of carbon dioxide (CO₂). While this is an important carbon reservoir, it holds a much smaller amount of carbon compared to other Earth systems. The carbon in the atmosphere is crucial for regulating the Earth’s temperature and supporting life processes such as photosynthesis. However, it represents only a tiny fraction of the total carbon on Earth.
- Biosphere: The biosphere, which includes all living organisms, holds a larger quantity of carbon compared to the atmosphere. This carbon is stored in plants, animals, and microorganisms. It is part of the carbon cycle, with carbon being taken up by plants during photosynthesis and returned to the atmosphere through respiration or decay.
- Geosphere: The geosphere, which refers to Earth’s solid interior, holds the vast majority of Earth’s carbon, mainly in the form of fossil fuels, carbonates, and other minerals. The carbon here is stored for millions of years, and it is much larger than the atmospheric or biospheric carbon.
- Hydrosphere: The hydrosphere, including oceans, rivers, and lakes, holds a substantial amount of carbon, especially in the form of dissolved carbon dioxide and carbonates in seawater. The oceans act as a major carbon sink, absorbing carbon from the atmosphere.
Overall, while the atmosphere plays a significant role in the carbon cycle, it is the smallest reservoir of carbon when compared to the other Earth systems. The geosphere and hydrosphere store the largest amounts of carbon.
