Trophic pathways of phytoplankton size classes through the zooplankton food web over the spring transition period in the north-west Mediterranean Sea
Type | Article | ||||||||||||
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Date | 2017-08 | ||||||||||||
Language | English | ||||||||||||
Author(s) | Hunt Brian P. V.1, 2, 3, Carlotti Francois3, Donoso Katty3, Pagano Marc3, D'Ortenzio Fabrizio4, Taillandier Vincent4, Conan Pascal5 | ||||||||||||
Affiliation(s) | 1 : Univ British Columbia, Inst Oceans & Fisheries, Vancouver, BC, Canada. 2 : Hakai Inst, Heriot Bay, BC, Canada. 3 : Univ Toulon & Var, Aix Marseille Univ, CNRS, IRD,MIO UM 110,Mediterranean Inst Oceanog, Marseille, France. 4 : UPMC Univ Paris 06, Sorbonne Univ, CNRS, Lab Oceanog Villefranche,UPMC,UMR 7093, Paris, France. 5 : UPMC Univ Paris 06, Sorbonne Univ, CNRS, UMR7621,Lab Oceanog Microbienne,Observ Oceanol, Banyuls Sur Mer, France. |
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Source | Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2017-08 , Vol. 122 , N. 8 , P. 6309-6324 | ||||||||||||
DOI | 10.1002/2016JC012658 | ||||||||||||
WOS© Times Cited | 23 | ||||||||||||
Note | This article also appears in: Dense water formations in the North Western Mediterranean: from the physical forcings to the biogeochemical consequences | ||||||||||||
Keyword(s) | zooplankton, isotopes, food web, phytoplankton, trophic pathways | ||||||||||||
Abstract | Knowledge of the relative contributions of phytoplankton size classes to zooplankton biomass is necessary to understand food-web functioning and response to climate change. During the Deep Water formation Experiment (DEWEX), conducted in the north-west Mediterranean Sea in winter (February) and spring (April) of 2013, we investigated phytoplankton-zooplankton trophic links in contrasting oligotrophic and eutrophic conditions. Size fractionated particulate matter (pico-POM, nano-POM, and micro-POM) and zooplankton (64 to >4000 mu m) composition and carbon and nitrogen stable isotope ratios were measured inside and outside the nutrient-rich deep convection zone in the central Liguro-Provencal basin. In winter, phytoplankton biomass was low (0.28 mg m(-3)) and evenly spread among picophytoplankton, nanophytoplankton, and microphytoplankton. Using an isotope mixing model, we estimated average contributions to zooplankton biomass by pico-POM, nano-POM, and micro-POM of 28, 59, and 15%, respectively. In spring, the nutrient poor region outside the convection zone had low phytoplankton biomass (0.58 mg m(-3)) and was dominated by pico/nanophytoplankton. Estimated average contributions to zooplankton biomass by pico-POM, nano-POM, and micro-POM were 64, 28 and 10%, respectively, although the model did not differentiate well between pico-POM and nano-POM in this region. In the deep convection zone, spring phytoplankton biomass was high (1.34 mg m(-3)) and dominated by micro/nano phytoplankton. Estimated average contributions to zooplankton biomass by pico-POM, nano-POM, and micro-POM were 42, 42, and 20%, respectively, indicating that a large part of the microphytoplankton biomass may have remained ungrazed. |
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