Determination of copepod grazing on natural plankton communities: correcting for trophic cascade effects

• Published in: Marine Ecology Progress Series
• Main Authors: Klaas, Christine, Verity, Peter G., Schultes, Sabine
• Other Authors: Max-Planck-Institut für Biogeochemie (MPI-BGC), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association, Skidaway Institute of Oceanography (SIO), Skidaway Institute of Oceanography, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: ecosystem model; copepod grazing; Southern Ocean; Rhincalanus gigas; Calanus simillimus SOUTHERN-OCEAN; ANTARCTIC COPEPODS; IRON FERTILIZATION; PREY POPULATIONS; ZOOPLANKTON; CHLOROPHYLL; IMPACT; GUT; SELECTIVITY; EISENEX; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Antarctic; Antarc*; Copepods
• Online Access: https://hal.univ-brest.fr/hal-00473804; https://hal.univ-brest.fr/hal-00473804/document; https://hal.univ-brest.fr/hal-00473804/file/m357p195.pdf; https://doi.org/10.3354/meps07262

International audience Grazing rates and grazing selectivity of Antarctic copepods (Rhincalanus gigas, Calanus simillimus and copepods 0.8 to 2 mm in size) were determined using incubation experiments comparing plankton community development with and without added grazers. Estimates of grazing rates were corrected for trophic cascade effects using a simple ecosystem model composed of 5 compartments: (1) nanophytoplankton, (2) nanozooplankton, (3) microphytoplankton, (4) microzooplankton (mainly protozoans) and (5) copepods. Copepod grazing rates on the different planktonic compartments were derived by solving for model parameters as constrained by microscopy enumeration of nano- and microphytoplankton and nano- and microprotozooplankton in treatments with and without added copepods. Simulations based on different parameter values and model configurations support the notion that grazing estimates were robust and between 18 and 30 % higher than uncorrected estimates. Furthermore, model analyses suggest the presence of an additional trophic cascade effect due to grazing of R. gigas on small copepods and copepod developmental stages present in incubation bottles.