Are Moderators appointed for life?

First off, I like most of the moderators on Fluther. There are a couple I truly cannot stand, although I feel at times that they may take a personal vendetta against certain members on here. I have no citable proof, but I do remember some questions and answers being moderated for somewhat unusual reasoning. My question is this: Have any of the mods ever done anything to warrant them being ‘made to walk the plank’ so to speak? If not yet, would that ever come up? How would that be handled?
Can we vote off the ones we think are ‘bossy’ or give preferential treatment? and no, I am not going to mention which of the mods I find disagreeable.