I believe the correct answer is upwelling. Lets say we have producers such as plankton. well upwelling currents bring dead matter from the ocean floor up to the surface, creating plankton.
I have no clue!! But I can deduce as much as I can for you!! ;)
So, venomous snakes always have two distinct properties: they are brightly colored and have the heart on their head (where they keep the venom). My guess would be that the king snake evolved to have bright colors so that other predators would think that it is poisonous and stay away.