When mercury pollutes the soil, the tiny microbes living there change how they work—they turn on genes that help them deal with the poison, which might help them survive in dirty environments.

Microbes in mercury-contaminated soil have more genes related to stress response, moving substances across cell membranes, and phosphate metabolism compared to less contaminated soils.

In places where the soil has been polluted with mercury for a long time, there are fewer types of bacteria living in the soil, especially when the pollution is really bad—but fungi don’t seem to be as affected, which means bacteria are more sensitive to mercury than fungi.

Soils with long-term mercury contamination may also have more bacteria that can resist antibiotics, because the same mechanisms that help with mercury resistance might also help with antibiotic resistance.

The amount of mercury that can actually be taken up by organisms doesn't always match the total mercury in the soil, showing that the chemical form of mercury matters more than just how much is present.

Just because soil has a lot of mercury doesn't mean it's all available to harm microbes—what matters more is the chemical form of the mercury and the soil's properties.