What can cause the release of methane and carbon dioxide from oil?

The release of methane and carbon dioxide from oil is primarily associated with microbial activity. Certain microorganisms can thrive in the anaerobic conditions present in oil reservoirs, where they break down organic matter through their metabolic processes. This action results in the production of methane, which is a significant component of natural gas, and carbon dioxide as byproducts.

These microbial communities can be particularly active in environments where there is organic material present, leading to the transformation of hydrocarbons into simpler gases. This process is essential in natural gas formation and affects the overall composition of hydrocarbon reserves.

The other options, while related to different phenomena, do not directly facilitate the microbial production of these gases from oil. For example, electrical arcing can create byproducts or damage but does not engage with the biological transformation process occurring in microbial activity. Oxidative stress and thermal expansion are also irrelevant in this context as they do not contribute to the biogenic processes that yield methane and carbon dioxide from oil.