Air carrier Captain reported airborne notification that dry ice had erroneously been loaded in the cargo pit with no ventilation. Captain contacted dispatch to alert the ramp personnel of possible fumes upon arrival.

Narrative

I was the pilot not flying on this leg. On the climbout after leaving sterile; I noticed that we had an unopened general ACARS message- I read it and saw that it said that dry ice was placed in the incorrect cargo hold (the one without ventilation) and that no notice to Captain was required. I informed the pilot flying (PF) about the situation- after reaching cruise; I asked if the PF would be able to take the radios while I called Operations ahead to inform ramp personnel about the mix-up and to be aware that there may be fumes from the lack of ventilation.As we were parking on the inbound leg; I noticed that there were a lot of new rampers in training. They all had supervisors and the trainers were very detailed; but never made a verbal mention of dry ice (usually standard); and they I failed to catch that they put it in the incorrect cargo hold.Suggestions: It would likely be a good idea to place placards in the aft cargo hold showing NO DRY ICE/LIVE ANIMALS to prevent future errors.