What happens to microbial activity in the soil when soil temperature increases?

When soil temperature increases, microbial activity in the soil generally increases. Microorganisms, including bacteria and fungi, are sensitive to temperature changes, and warmer conditions typically accelerate their metabolic processes. As temperatures rise, the enzymes produced by these microbes become more active, leading to faster rates of nutrient cycling and decomposition of organic matter.

This increased microbial activity can enhance soil health by improving nutrient availability to plants and contributing to soil structure through the production of organic matter. However, there is a threshold beyond which excessively high temperatures can be detrimental, but within the optimal range, microbial populations thrive and their activity levels rise.

The other options do not accurately represent the relationship between temperature and microbial activity. A significant decrease or remaining unaffected does not typically occur as soil temperature increases to moderate levels where biological functions are supported. Additionally, while moisture levels indeed influence microbial activity, the primary driver related to temperature is the direct effects of thermal conditions on microbial metabolism and growth.