Discoveries like these make me think that our system of ethics is going to have been seriously revised by 2100.
Hoever, I don't think Dolphins will be recognised as persons, even non-human ones, until we have a means of reliably communicating with them. We do know that pods communicate with one another with their own basic languages but is it sophisticated enough to convince people of their intelligence?
I really hope we don't have missionaries diving down to try to convert the dolphin race, they seem to be gleefully unaware of religion at the moment. Although it would be funny if the Dolphins listened to their pitch and then said "No, sorry, that's just whaleshit"