Abstract
Jellyfish are commonly neglected in ecological studies and data that are necessary for quantifying the carbon flux through this part of the pelagic community are lacking. The aim is to study energetics of key gelatinous zooplankton species with special attention to assimilation and production. By applying laboratory determined carbon budgets and vital rates to data on abundance, size and growth in the field, to the project will evaluate both direct and indirect effects of predation by gelatinous species in coastal waters. The target area will be the Gullmar fjord, west coast of Sweden, but the bioenergetic information obtained is generally applicable. We will sample the fjord to cover seasonal dynamics, and jellyfish will be monitored along with environmental and biological parameters relevant for other trophic levels including vertical distribution during blooms. In the laboratory we will combine traditional approaches with novel isotope tracer techniques. In controlled experiments, feeding, growth, DOC release, assimilation and respiration of the dominant gelatinous predators will be measured in relation to prey abundance and prey species. The project will contribute considerable to our understanding of predation and cascading effects of gelatinous predators in general. Most likely it will change our current view of the effect of gelatinous predators since their role in the ecosystem has been severely underestimated until now.
Sweden