What is the importance of hydrocarbons to the natural environment?

Question

I have not been able to find any scholarly resources citing the impact of hydrocarbons in stasis underground.

Hydrocarbons not being used for as a source of energy have very few noted needs for the environment.

Do these “fossil fuels” underground help maintain homeostasis in microbial ecosystem or aid in the growth of flora etc?

Or are these substances: coal, animal remains and natural gas detrimental even if left untouched? Since most methods of break down are no longer an option due to decomposers not being able to reach these substances?

https://www.ucsusa.org/resources/environmental-impacts-natural-gas

https://www.nature.com/scitable/knowledge/library/the-ecology-of-carrion-decomposition-84118259/

Answer 1

Hydrocarbons exist as short chain molecules; that act as feedstock for biological consumption. As just geologically stored carbon, it's useless. Apart from methane and ethylene, hydrocarbons as a whole play no large biological role. As hydrocarbons. When humanity re-released this carbon into the Biosphere as $\ce{CO2}$ it drove stockpiles of available carbon for biology up. All photosynthetic organism... plants, bacteria, algae needs $\ce{CO2}$ in order to produce sugars that are the primary energy source for every plant and animal. To be fair, water is also essential, as are nitrogen, potassium, phosphorus, and many other minor elements. But $\ce{CO2}$ is the most important, as all life on earth is carbon-based, and the carbon comes from $\ce{CO2}$ in the atmosphere.