56, No. 1, 2011 Direct and indirect effects of an invasi... The relative importance of top-down invader effects relative to environmental drivers was determined by sampling crustacean zooplankton, ...

Small fish, crustaceans, and zooplankton feed on phytoplankton. Those creatures are then eaten by larger fish and corals, which, in turn become food for top ocean predators like sharks.

Pictured: One of the zooplankton found in the water samples is the adult copepod, a miniature crustacean that is about the size of the period at the end of this sentence.

According to Phys.org, which relayed the university's findings, the scientists looked at the meat from six different fish and crustaceans ... smaller food items like zooplankton.