Consider the following: on an annual basis,C exchange from photosynthesis is 120 Gt,decomposition is 60 Gt,respiration is 60 Gt,ocean uptake of CO₂ is 92 Gt of C,ocean release is 91 Gt of C,release of C to the atmosphere from anthropogenic sources (fossil fuel use and land use change)is 6 Gt,and the atmosphere is increasing by 3.2 Gt of C.If terrestrial processes are responsible for the remaining C for net balance of the C cycle,then which of the following is likely?

Question

Quizplus · Accepted Answer

The terrestrial surface is a net sink because the increase in atmospheric carbon (3.2 Gt) is less than the anthropogenic emissions (6 Gt), indicating that the difference (2.8 Gt) is absorbed by terrestrial and oceanic processes. Given that the ocean uptake and release almost balance out (92 Gt uptake vs. 91 Gt release), the terrestrial surface must absorb the remainder, which is 1.8 Gt (2.8 Gt total minus 1 Gt net ocean uptake).

Consider the Following: on an Annual Basis,C Exchange from Photosynthesis