The current doctor (the tenth) will regenerate in the final special of 2009. Other than that there have been loads (old age, exile by Time Lords, radiation from cave, falling off radio telescope, etc ....
He will regenerate into the 12th Doctor.
He'll regenerate into the 13th Doctor.
The fourth Doctor fell off a bridge.
Eventually yes, he will regenerate into the twelfth Doctor.
Romana was another Time Lord, like the Doctor.
Peter Davison.
In the movie, The End Of Time.
Time Lords regenerate because they have a injury or something is wrong, it's their way of healing themselves.
It is unknown, the Eighth Doctor only appeared in a movie.
Trenzalore (his final resting place), in the town of Christmas
He was poisoned and used the last of the antidote to save his companion, Peri.
I dont think he was in an ocean... He was in the Tardis...?