2019 REUs presented at the CERF Conference in Mobile, AL
Predator-prey interactions of copepod Eurytemora carolleeae nauplii and dinoflagellate Heterocapsa rotundata in winter conditions
Atlantic Estuarine Research Society Fall Meeting, Galloway, New Jersey
We quantified the potential impacts of nauplii of the copepod Eurytemora carolleeae on abundances of the dominant winter bloom forming dinoflagellate, Heterocapsa rotundata. Both H. rotundata winter blooms and E. carolleeae nauplii are understudied but likely contribute to production and trophic dynamics throughout the winter in estuaries and coastal systems. We conducted grazing and survival experiments to determine ingestion, clearance, and mortality rates of nauplii according to varying concentrations of H. rotundata. The functional response of the nauplii fit a Holling type II response with a maximum ingestion (Imax) of 0.2 µg copepod-1 day-1 and half saturation constant (K) of 245.2 µg C L-1 increased survivability of nauplii compared to when no food was present. As H. rotundata concentrations increased, the number of nauplii supported and the total amount of carbon removed increased but the percent of the total carbon concentration removed decreased. Nauplii in a supported population can remove on average 11% of the H. rotundata standing stock and thus do not seem capable of depleting their food supply in a stable population. This has important implications for fish larvae that feed on E. carolleeae copepodites in the spring.