Our researchers found these guys in Guana River. Here are two microscopic zooplankton species – A Favella species has eaten a Ceratium species. Favella is a tintinnid ciliate. Tintinnids are a vital link in aquatic food chains as they are the ‘herbivores‘ of the plankton. They feed on phytoplankton (algae and cyanobacteria) and in turn act as food for larger organisms such as copepods (small crustaceans) and larval fish (Stoecker 2013). Ceratium is a dinoflagellate. Species of Ceratium are mixotrophic, meaning they are both photosynthetic and heterotrophic, consuming other plankton. The smaller brown ovals in Favela are likely small phytoplankton, which get their energy directly from sunlight. So, in this one picture, you see three trophic levels (all microscopic)!