FIELD TESTING CHARACTERIZATION OF LOWER NIAGARA RIVER DAPHNIA DIET USING 16S RRNA AND 18S RRNA GENE SEQUENCING

Zooplankton regulate the flow of carbon and nutrients from phytoplankton to higher trophic levels. Previous efforts to differentiate food choice have focused on fatty acid profiles and stable isotopies, with the recent efforts in genetic identification of prey in dissected guts of larger marine zooplankton. Our work clarifies the energy and nutrient flow in their respective ecosystems. We have developed and lab tested a technique to determine diet content in a model zooplankton, Daphnia, using rDNA extraction through whole organism digestion. In this study, we field tested this method by determining the diet of Daphnia galeata collected from the lower Niagara River, NY and compared this to the phytoplankton community. We extracted DNA from whole D. galeata and river water phytoplankton samples followed by amplicon sequencing of the 16S rRNA V3-V4 region and 18S rRNA V4 region. The D. galeata selected Micrococcales, despite Frankiales and Microtrichales being most prevalent bacterial genera in the water column, and chose Monogononta over the more prevalent alga Cladophorales, suggesting selective feeding. Moving forward, we will be able to use this method successfully developed in the Niagara River to understand feeding patterns and nutrient cycling in other major lake and river systems.

Primary Presenter: Samantha Wrobel, Niagara University (swrobel@mail.niagara.edu)

Authors:

Samantha Wrobel, Niagara University  (swrobel@mail.niagara.edu)

Ciaran Edwards, Niagara University  (ciaranowls@gmail.com)

Cassandra Marnocha, Niagara University  (cmarnocha@niagara.edu)

William Edwards, Niagara University  (wje@niagara.edu)

Coleen Edwards, Niagara University  (cte@niagara.edu)