What environmental factor most significantly affects the metabolism and growth of microorganisms in water supplies?

Temperature plays a critical role in the metabolism and growth of microorganisms in water supplies. It influences various biochemical reactions and can affect enzyme activity, energy production, and overall microbial reproduction rates. Each species of microorganism has an optimal temperature range where it thrives, and deviations from this range can lead to slowed growth or even microbial die-off.

In warmer temperatures, microbial metabolism often speeds up, resulting in higher rates of growth and reproduction, potentially leading to increased concentrations of microorganisms. Conversely, lower temperatures can impede metabolic processes, resulting in slower growth or dormancy in some microbial species. This makes temperature a pivotal environmental factor in monitoring and managing water quality, especially in maintaining safe drinking water supplies.

While pH, oxygen levels, and salinity are also important factors that can affect microorganisms, their influence is often secondary to that of temperature, particularly concerning the rates of metabolism and growth.