Death may accelerate and become exponential. Many organism need it for respiration . If these organism need increased carbon dioxide they are called capnophilic . Note that there is a battle for iron between the human host and many infectious agents. We make lactoferrin and transferrin to capture and hold onto iron.
Many bacteria make siderophores to capture and hold onto iron.
For many of these we commonly refer to optimum , maximum and minimum . This organism makes ammonia to neutralize the stomach acid around it. Mesophiles have an optimum growth temperature around human body temperature. Thermophiles have a hot optimum growth temperature. Cold temperatures are often used to slow microbial growth and thus preserve foods.