Which of the following effects can lead to a loss of microbial function in soils?

Contamination with heavy metals can significantly disrupt microbial function in soils. Heavy metals, such as lead, cadmium, and mercury, are toxic to many forms of life, including bacteria and fungi that play essential roles in nutrient cycling and organic matter decomposition. When soils become contaminated with these metals, they can inhibit the metabolic processes of microbes, reduce their diversity, and ultimately result in a decline in soil health. The high toxicity levels can affect microbial growth, reproduction, and even survival, leading to diminished microbial activity.

In contrast, increased soil erosion can affect soil structure and nutrient availability but does not directly inhibit microbial function in the same way. High levels of organic matter typically support microbial life by providing necessary nutrients and energy sources. Natural biological processes generally enhance microbial function by promoting interactions within soil ecosystems. Therefore, contamination with heavy metals is a primary factor that can lead to a substantial loss of microbial function in soils.