The best example of a biogeochemical showing the interaction among various organisms and the impact of human activity is the carbon cycle.
Carbon cycle represents the biogeochemical cycle that shows the movement of carbon compounds in the environment. It involves the atmosphere, hydrosphere,pedosphere and the biosphere of the earth. The producers or the plants use the atmospheric carbon dioxide for the process of photosynthesis to produce organic compounds. It is further passed to the various consumers or the heterotrophs of the food chain. Cellular respiration by these organisms releases carbon dioxide back to the atmosphere. The decomposers act on the dead organisms and release carbon compounds back to the atmosphere.
Human activities like burning of fossil fuels and deforestation which is the cutting of trees have contibuted excessively to the increase in carbon dioxide in the atmosphere. Carbon dioxide being a green house gas has also led to the global warming. Thus, burning of fossil fuels, aforestation or planting more trees can reduce the human impact on ecosystem.