Marquess joined the teen drama earlier this month as a successor for Lucy Allan, who recently announced that she had quit her role as leading producer after a year in office.
According to the Daily Star, the show's team have since been bracing themselves for a massive overhaul as Marquess has a reputation for instigating cast clear-outs following his past work on The Bill and Family Affairs.
A source said: "Paul is known for having the balls to make serious changes to the cast if he thinks things need a good shake-up. Everyone is expecting a mass cull."
It is thought that there has been an "air of change" around the soap's set since Marquess began work on January 17.
The insider added: "Things do need a bit of a shake-up. Like any soap, you need to keep things fresh. If that means out with the old and in with the new, then so be it."