Abstract

The ability for marine ecosystems to maintain productivity and functionality under long term changes in resource availability relies on the diversity of functional groups. Nevertheless, the complexity of zooplankton interactions is rarely considered in trophic studies because of the lack of detailed information about feeding interactions in nature. In this study, we used DNA metabarcoding to detect trophic interactions of a wide range of micro- and mesozooplankton including ciliates, rotifers, cladocerans, copepods and their prey, by sequencing 16- and 18S rRNA genes. Our study demonstrates that functional group diversity goes beyond both phylogeny and size and reinforces the importance of diversity in resource use for stabilizing food web efficiency by allowing for alternative pathways of energy transfer. We further demonstrate the importance of ciliates and rotifers in recycling organic matter from degraded filamentous cyanobacteria within the pelagic zone, contributing to ecosystem production. The approach used in this study is a suitable entry point to ecosystem-wide food web modeling considering species-specific resource use of key consumers.