Zooplankton Predation

Through this cruise aboard R/V Endeavor we aim to gather preliminary data in support of a collaborative National Science Foundation proposal that leverages the established North East Shelf Long Term Ecological Research site(NES-LTER), and leverage this historical data set to investigate marine food web structure and the flow of energy. Specifically, we will conduct combined growth and grazing experiments of different size classes of zooplankton (micro- and microzooplankton, < 200 µm and >200 µm, respectively) to uncover their relative grazing pressure on primary production, the occurrence of trophic cascades, and the potential for carbon export to higher trophic levels including forage fish. Our rate measurements will be paired with ship board characterization of particles with a particle size analyzer (Coulter Counter), flowcytometry, and FlowCam (an image-based plankton analyzer). At each station, water column variables including temperature, salinity, PAR will be measured in depth profiles. Discrete water samples for concentrations of nutrients and chlorophyll a will be captured with the CTD. In addition, MOCNESS tows will be done for the collection of larger zooplankton and water will be collected with the Niskins for incubation experiments using deck-board incubators. The methods and protocols are established and have been utilized on the R/V Endeavor. Thus, we think this is a straightforward cruise with a high likelihood of success. The results would enable us to seek follow on funding and ship time for work in the region on planktonic food webs that are fundamental to the ecological services provided. Importantly, these food webs are subject to to-date little known climate forcings and thus in urgent need of investigation.