Climate scientists have observed seasonal changes in atmospheric carbon dioxide concentration. In the Northern Hemisphere, they have measured the highest levels of carbon dioxide in the month of May. They have also measured the lowest levels of atmospheric carbon dioxide in the month of October. Hypothesize how photosynthesis can affect these changes. Consider the process of photosynthesis and its inputs and outputs. Explain your answer in three to five sentences.

Things to keep in mind as you develop your hypothesis:

In the Northern Hemisphere, leaves appear on trees in the spring and fall from trees in the autumn.
Leaves are where photosynthesis occurs.
How does photosynthesis effect carbon dioxide?
(4 points)

1 answer

Photosynthesis plays a crucial role in seasonal changes in atmospheric carbon dioxide concentration. During spring and summer, when trees and plants are fully leafed out, the rate of photosynthesis increases, leading to a significant uptake of carbon dioxide (CO2) from the atmosphere as plants convert it into glucose and oxygen. This process results in lower atmospheric CO2 levels, which typically reach their peak in May, just before the onset of summer when photosynthesis is at its height. Conversely, in autumn, as leaves fall and photosynthetic activity declines, less CO2 is absorbed by plants, leading to a rise in atmospheric CO2 levels, which is why October typically records the lowest concentrations. Thus, the seasonal cycles of leaf growth and decay directly impact the levels of atmospheric CO2 through photosynthesis.