This comes via a 2K Games fact sheet:
"All-new PLAYSTATION 3 system exclusive content: In addition to the original revolutionary game experience, PLAYSTATION 3 system fans can enjoy a brand new difficulty mode – Survivor – as well as enjoy Trophy support as they explore Rapture. And the experience doesn’t end there – all new exclusive BioShock downloadable content will be available only on the PLAYSTATION 3 system after launch"
Nice to see the PS3 version will be getting new content, especially Trophy support. However, I can't imagine them being much different than the Achievements.