Regular, annual fluctuations in atmospheric carbon dioxide concentrations occur because?

Question

a. photosynthesis stops at night while respiration continues

b. humans influence the carbon dioxide concentrations

c. carbon dioxide emissions increase in the winter

d. plants in the northern hemisphere lose their leaves during the winter

e. volcanic eruptions add carbon dioxide to the atmosphere

Answer 1

D

There is an annual fluctuation of about 3-9 ppm in the measurements, which roughly follows the Northern Hemisphere's growing season. The Northern Hemisphere dominates the annual cycle of CO2 concentration because it has much greater land area and plant biomass than the Southern Hemisphere. Concentrations peak in May as the spring greenup begins and reach a minimum in October when the quantity of biomass undergoing photosynthesis is greatest.