Community composition, functional traits, and trophic structure of zooplankton size fractions across an oligotrophic-eutrophic gradient

PowerPoint Presentation Community composition, functional traits, and trophic structure of zooplankton size fractions across an oligotrophic-eutrophic gradient Brian Hunt, Francois Carlotti, Evgeny Pakhomov Food web implications of phytoplankton size structure Zooplankton are the intermediaries between primary producers and tertiary consumers Phytoplankton size structure determines trophic pathway. [...] Small particle grazers would be the dominant grazers in oligotrophic conditions and large crustaceans grazers in eutrophic conditions. [...] Herbivory would extend into larger size fractions under eutrophic conditions; In Southern Ocean (micro-phyto dominated) and Marquesas Islands (nano- phyto dominated) 2. [...] Eutrophic conditions - response of zooplankton community appears dependent on dominant phytoplankton size class • Microphytoplankton dominance favours large crustaceans omnivorous grazers • Nanophytoplanton dominance can favour large tunicate grazers Therefore important to take into account phytoplankton size structure in addition to biomass when predicting zooplankton response to changing ocean c. [...] Community composition, functional traits, and trophic structure of zooplankton size fractions across an oligotrophic-eutrophic gradient Food web implications of phytoplankton size structure Food web implications of phytoplankton size structure Project Aims SeaWiFs global chl (mg.m-3); Sep 1997 - Dec 2010 Regional phytoplankton production Methods Zooplankton community composition Zooplankton commun.