Photon Strike Bounzer (Bujingi Turtle) VS Book of Moon

If a monster's effect is activated and Photon Strike Bounzer (or Turtle) chain to that effect to negate it, and then Book of Moon is chained so the monster that activated its effect is now face-down, Strike Bounzer (or Turtle) will still negate that monster's effect. All Bounzer cares for is an effect to be activated on the field, it doesn't matter to it what happens to the monster after that.