#oxygen gradient

• Aerotaxis — A specific form of taxis or directed orientation and movement reaction of mobile microorganisms (bacteria, protozoa) triggered by the presence, concentration level, or partial pressure variation of oxygen or other gases in their living environment. This structural phenomenon guides aerobic bacteria toward oxygen-rich zones and anaerobic ones away from them.
• Aerotropism — A specific form of tropism or oriented growth movement of plant vegetative organs, such as roots or mycelial filaments, determined by the presence of air or the variation of oxygen concentration in the surrounding environment. This structural phenomenon allows plants to guide their roots toward well-aerated soil layers or to develop respiratory structures above water.