One Cell at a Time: Investigating Grazing Habits of Neomysis americana in the Patuxent River Using Flow-Cytometry
Neomysis americana are an abundant species of key importance in coastal and estuarine communities, linking primary and secondary productivity as an omnivore in the plankton community and as an important food source for many fish species. Yet little is known about their preferential diets within the plankton community. This study utilizes flow cytometry to assess the grazing habits of N. americana at two sites in the Patuxent River, Maryland and at both the surface (both sites) and bottom (one site) of the water column. Several taxonomic groups of phytoplankton consistently occurred in both sites and in the upper and lower water column. Individuals collected from an automated sort of each group indicated these included cyanobacteria, dinoflagellate, diatom, and green algae groups. An overall increase in cell concentrations of cyanobacteria was seen in the majority of the mysid grazing trials from both sites. A decreasing trend in dinoflagellates and diatoms at both sites suggests a preference for these functional groups as forage. Across all three treatment levels, the largest loss of cells was observed for green algae. This study developed a methodology for pairing flow cytometry with live animal grazing experiments, yielding techniques that refine and build on more traditional methods for studying zooplankton grazing. This work also informs future studies on potential avenues for research in mysid grazing, which will ultimately lead to a greater understanding of their role in Chesapeake Bay food webs.