SCRIPPS INSTITUTION OF OCEANOGRAPHY FACULTY CANDIDATE SEMINAR -
DATE: April 29th, Monday, 12 p.m.
LOCATION: Eckart 227
TITLE: Gelatinous zooplankton ecology from the organism to the ecosystem scale
Gelatinous zooplankton, spanning cnidarian medusae and chordate pelagic tunicates, are common yet frequently overlooked members in marine ecosystems. Though gelatinous organisms range in size from mm to m, feeding elements are often in the sub-mm to sub-micron range. Collectively, through these sub-mm processes, jellies strongly mediate food web interactions. In my lab, we use a combination of approaches including in situ and lab incubation experiments, flow visualizations, high-speed video and sampling from oceanographic ships to uncover trophic links between gelatinous zooplankton and microbial communities and also with higher order predators (e.g. fish) in the context of environmental variables. In my talk, I’ll develop two stories— one centered on cnidarian medusae (Obelia sp., Chrysaora fuscescens) and one centered on appendicularians (primarily Oikopleura dioica)—to highlight our approach of linking scales from organisms to ecosystems. In medusae, tentacle-level nematocyst distributions and boundary layers ultimately dictate community level impacts. In appendicularians, changes in tail beat frequency control flow patterns and the adhesion of particles on the complex filtering apparatus, ultimately determining which microbial constituents are captured and which ones slip through the mesh. Non-uniform selection of prey particles by gelatinous organisms on the basis of size, shape, surface properties and behavior recasts our understanding of the microbial loop and the export of material from surface waters to the deep ocean. Grazing impacts can be magnified during population blooms or range expansions such as the recent bloom of Pyrosoma atlanticum off the west coast of north America. Robust quantification of interactions among species, especially critically understudied gelatinous zooplankton, is highly relevant to the field of oceanography both now and in future scenarios.