Evidence for a tightly coupled nanoplanktonic predator-prey link regulating the bacterivores in the marine environment

A coupled predator-prey chain, starting with bactenvores, was invest~gated using the mlnicell recapture technique (MiniCap) Water samples were subjected to slze fract~onation w t h decreasing filter pore s u e in order to obtain a successive truncation of the microbial food chaln Our results showed that the malor bacterivores were flagellates in the size range of 1 to 3 pm The truncation of the food chain caused increased or decreased predation on the bactena, d e p e n d ~n g on whether the bacterivores 'ivere released from or subjected to increased predat~on pressure We present a model describing trophic interactions between organisms less than 12 pm In size This model suggests 4 trophic levels to form a regulatory chain exert~ng a tight control on major bacterivores