How do plankton or other microorganisms respond to different cues in their environment? How do they respond to each other?

Objective: Create a microscope platform that allows for easy observation and analysis of microorganism behavior in response to cues in its environment.

How do microorganisms respond to common chemicals found in the house salt, sugar, food, detergent, alcohol, fertilizer, charcoal, heat, or vinegar?
How do plankton interact? Which are predators and which are prey?
Can microorganisms respond to sound/vibration or light?