Effect of Exopolymers on the Consumption of Synechococcus by Oxyrrhis marina

Abstract

Microscopic organisms play an important role in carbon cycling in the ocean. Because of their large role, understanding how their activity is affected by other organisms and by particles in the water is important to understand the oceanic carbon cycle and flow of energy through food webs. This experiment was designed to determine what effect, if any, transparent exopolymer particles (TEP) have on the consumption of Synechococcus by Oxyrrhis marina. O. marina is a heterotrophic marine dinoflagellate that has the potential to be a model organism for heterotrophic dinoflagellates and protists. Synechococcus is a cyanobacterium that is responsible for a quarter of yearly marine net primary production. Because TEP are adhesive, they form aggregates of small particles such as Synechococcus. In this experiment, cultures containing O. marina and Synechococcus with TEP added saw a significant increase in the average number of Synechococcus consumed by O. marina. This is likely because the size of the aggregates of Synechococcus formed by TEP are more appealing to O. marina than individual Synechococcus cells. The results of this experiment suggest that the presence of TEP will increase the amount of carbon flow to upper trophic levels by causing higher consumption at lower levels due to prey aggregation.