This is a simplified diagram of the carbon cycle, as it also involves water bodies and decomposer organisms that are not found in this case.
First, we have the carbon sources, these involve living organisms that through respiration, waste production, and decomposition expel CO2 into the environment. This includes terrestrial, marine, and even plant organisms that expel CO2 when they breathe.
Another source of carbon is manufacturing, human activities, and natural disasters such as volcanic eruptions. All these factors together promote the production of CO2 and release it into the environment.
To close the cycle, plant organisms take carbon from the environment (CO2) and through photosynthesis use it to produce sugars that can be consumed by the organisms again.
The white shark would be in the middle of the image along with the other organisms.