sump/fuge questions - baffles vs tank dividers?

My major reason for wishing to divide my sump is to have a refugium section in which to breed brine shrimp, pods, etc., and to hold the macroalgae, so that neither the macro nor the animal life get caught up in the filters and pumps. Therefore I will need to add something other than baffles, like the Lee's tank dividers or something that will screen out small life forms. Do I need baffles as well? I've seen discussion regarding the baffles preventing microbubbles from getting into the DT. Why would that be necessary? What problems are caused by the microbubbles?