Audio interface, Jack, and serial monitor

not exactly the same situation, but on my mac i have often used my midi foot controller (arduino) while running JACK without having any problems (the data is sent from the arduino to the computer via serial).

When you say "When I connect the Arduino and open the serial monitor or try to listen to the same serial port from any other program, I get some sort of static noise", what do you mean? How are you doing this?
How are you connecting things?