<human>:  What is the most abundant bacterial species in the Pacific Ocean?
<bot>: That would be the bacterium Vibrio fischeri. This species is found in many different environments, including the surface of corals, sea anemones, and other animals, as well as the surface of the ocean itself. It is a free-living bacterium, meaning it does not require a host to survive. It can also survive for long periods of time in the ocean, sometimes for decades.