How does carbon become available to plants

Comments Close. The Comment you have entered exceeds the maximum length. Submit Cancel. Comments Please Post Your Comment. No comments yet. Save Note Note. Save Cancel Delete. Next Prev Close Edit Delete. You have authorized LearnCasting of your reading list in Scitable. Generally, about half of the caught carbon is released in respiration. Plant leaves such as needles retain the carbon dioxide by the process of photosynthesis and release it by the process of respiration.

Photosynthesis needs light, whereas respiration happens both in light and dark. Both processes are strongly affected by temperature and water availability. When there is enough light and the air temperature is above zero, we can see photosynthesis as a flow of carbon dioxide molecules towards the crown: carbon dioxide enters needles through the pores located at the needle surface the stomata.

At the same time, we can see carbon dioxide being released out of the canopy. This carbon dioxide is produced in respiration. When it is dark, the only flow of CO2 comes from respiration and it is thus outwards from the canopy. The tree mostly release carbon dioxide due to the respiration of the living cells in its interior. In some part of the stems, some photosynthesis may also happen.

In the Northern Hemisphere winter, when few land plants are growing and many are decaying, atmospheric carbon dioxide concentrations climb. During the spring, when plants begin growing again, concentrations drop. It is as if the Earth is breathing. The ebb and flow of the fast carbon cycle is visible in the changing seasons. As the large land masses of Northern Hemisphere green in the spring and summer, they draw carbon out of the atmosphere.

This graph shows the difference in carbon dioxide levels from the previous month, with the long-term trend removed. This cycle peaks in August, with about 2 parts per million of carbon dioxide drawn out of the atmosphere. In the fall and winter, as vegetation dies back in the northern hemisphere, decomposition and respiration returns carbon dioxide to the atmosphere.

Atmosphere Land. EO Explorer. At the time of publication, it represented the best available science. The animals and plants eventually die. Dead organisms are eaten by decomposers and carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel for combustion in the future.