Metabarcoding and metabolome analyses of copepod grazing reveal feeding preference and linkage to metabolite classes in dynamic microbial plankton communities.
In order to characterize copepod feeding in relation to microbial plankton community dynamics, we combined metabarcoding and metabolome analyses during a 22-day seawater mesocosm experiment. Nutrient amendment of mesocosms promoted the development of haptophyte (Phaeocystis pouchetii)- and diatom (Skeletonema marinoi)-dominated plankton communities in mesocosms, in which Calanus sp. copepods were incubated for 24 h in flow-through chambers to allow access to prey particles (<500 μm). Copepods and mesocosm water sampled six times spanning the experiment were analysed using metabarcoding, while intracellular metabolite profiles of mesocosm plankton communities were generated for all experimental days. Taxon-specific metabarcoding ratios (ratio of consumed prey to available prey in the surrounding seawater) revealed diverse and dynamic copepod feeding selection, with positive selection on large diatoms, heterotrophic nanoflagellates and fungi, while smaller phytoplankton, including P. pouchetii, were passively consumed or even negatively selected according to our indicator. Our analysis of the relationship between Calanus grazing ratios and intracellular metabolite profiles indicates the importance of carbohydrates and lipids in plankton succession and copepod-prey interactions. This molecular characterization of Calanus sp. grazing therefore provides new evidence for selective feeding in mixed plankton assemblages and corroborates previous findings that copepod grazing may be coupled to the developmental and metabolic stage of the entire prey community rather than to individual prey abundances.
Hjort Centre for Marine Ecosystem Dynamics, Uni Research Environment, Uni Research AS, Nygårdsgaten 112, Bergen, N-5008, Norway. jessicalouiseray@gmail.com.
Jessica L
JL
Ray
Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstr. 8, Jena, 07443, Germany.
Julia
J
Althammer
Hjort Centre for Marine Ecosystem Dynamics, Uni Research Environment, Uni Research AS, Nygårdsgaten 112, Bergen, N-5008, Norway.
Katrine S
KS
Skaar
Department of Biology, University of Bergen, Thormøhlensgt 53A, Bergen, 5006, Norway.
Paolo
P
Simonelli
Hjort Centre for Marine Ecosystem Dynamics, Uni Research Environment, Uni Research AS, Nygårdsgaten 112, Bergen, N-5008, Norway.
Aud
A
Larsen
Horn Point Lab, Center of Environmental Science, University of Maryland, Cambridge, MA, 21613, USA.
Diane
D
Stoecker
Laboratory of Ecology of Plankton Organisms, Russian Academy of Sciences, P.P. Shirshov Institute of Oceanology, Nakhimovsky Prospect 36, Moscow, Russia.
Andrey
A
Sazhin
School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK.
Umer Z
UZ
Ijaz
WMS - Microbiology and Infection, University of Warwick Medical School, Coventry, CV4 7AL, UK.
Christopher
C
Quince
Department 3, Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, Stechlin, OT Neuglobsow, 16775, Germany.
Jens C
JC
Nejstgaard
Hjort Centre for Marine Ecosystem Dynamics, Uni Research Environment, Uni Research AS, Nygårdsgaten 112, Bergen, N-5008, Norway.|Skidaway Institute of Oceanography, 10 Science Circle, Savannah, GA, 31411, USA.
Marc
M
Frischer
Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstr. 8, Jena, 07443, Germany.
Georg
G
Pohnert
Hjort Centre for Marine Ecosystem Dynamics, Uni Research Environment, Uni Research AS, Nygårdsgaten 112, Bergen, N-5008, Norway.
Christofer
C
Troedsson
D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D033342:Copepoda / Q000235:genetics / Q000502:physiology*; D058893:DNA Barcoding, Taxonomic; D017377:Diatoms; D005247:Feeding Behavior; D008055:Lipids / Q000032:analysis; D055442:Metabolome; D010839:Phytoplankton; D010933:Plankton; D012623:Seawater
D002241:Carbohydrates; D008055:Lipids

Phaeocystis pouchetii
; 
Skeletonema marinoi
; Calanus grazing; eukaryote V7 SSU; metabarcoding; metabolome profiling; seawater mesocosms; symbiosis