(1) The main ecological services are fixation of atmospheric CO2 and release of O2 are the most important services provided by an ecosystem.
(2) Photosynthetic activity of photoautotrophs helps in carbon sequestration in the form of CO2 from the atmosphere. At the same time it releases O2 as a byproduct.
(3) O2 is needed for respiration by all aerobic organisms. Oxygen also purifies air.
(4) For human consumption, crops and fruits are continuously required. These can be produced only after pollination of plants. Wind, water or other biotic agent such as insects therefore play an important role as ecosystem service. Without pollination there would be no crops and no fruits.
