The chemical energy of photosynthesis can be passed on to other living or biotic components of an environmental system through biomass consumption or decomposition by consumer organisms. When needed for metabolic processes, the fixed organic energy stored in an organism can be released to do work via respiration or fermentation . Energy also fuels a number of environmental processes that are essentially abiotic. For example, the movement of air by wind , the weathering of rock into soil , the formation of precipitation , and the creation of mountains by tectonic forces. The first three processes derive their energy directly or indirectly from the sun's radiation that is received at the Earth's surface.
Mountain building is fueled by the heat energy that exists within the Earth's interior.
Finally, the movement of energy in environmental systems always obeys specific thermodynamic laws that cannot be broken. We will learn more about these laws later in this textbook.