Leblanc K., Cornet V., Caffin M., Rodier Martine, Desnues Anne, Berthelot H., Turk-Kubo K., Heliou J. (2016). Phytoplankton community structure in the VAHINE mesocosm experiment. Biogeosciences, 13 (18), p. 5205-5219. ISSN 1726-4170.
Titre du document
Phytoplankton community structure in the VAHINE mesocosm experiment
Année de publication
2016
Auteurs
Leblanc K., Cornet V., Caffin M., Rodier Martine, Desnues Anne, Berthelot H., Turk-Kubo K., Heliou J.
Source
Biogeosciences, 2016,
13 (18), p. 5205-5219 ISSN 1726-4170
The VAHINE mesocosm experiment was designed to trigger a diazotroph bloom and to follow the subsequent transfer of diazotroph-derived nitrogen (DDN) in the rest of the food web. Three mesocosms (50m(3)) located inside the Noumea lagoon (New Caledonia, southwestern Pacific) were enriched with dissolved inorganic phosphorus (DIP) in order to promote N-2 fixation in these low-nutrient, low-chlorophyll (LNLC) waters. Initially, the diazotrophic community was dominated by diatom diazotroph associations (DDAs), mainly by Rhizosolenia/Richelia intracellularis, and by Trichodesmium, which fueled enough DDN to sustain the growth of other diverse diatom species and Synechococcus populations that were well adapted to limiting DIP levels. After DIP fertilization (1 mu M) on day 4, an initial lag time of 10 days was necessary for the mesocosm ecosystems to start building up biomass. However, changes in community structure were already observed during this first period, with a significant drop of both Synechococcus and diatom populations, while Prochlorococcus benefited from DIP addition. At the end of this first period, corresponding to when most added DIP was consumed, the diazotroph community changed drastically and became dominated by Cyanothece-like (UCYN-C) populations, which were accompanied by a monospecific bloom of the diatom Cylindrotheca closterium. During the second period, biomass increased sharply together with primary production and N-2-fixation fluxes near tripled. Diatom populations, as well as Synechococcus and nanophytoeukaryotes, showed a re-increase towards the end of the experiment, showing efficient transfer of DDN to nondiazotrophic phytoplankton.
Plan de classement
Ecologie, systèmes aquatiques [036]
Description Géographique
NOUVELLE CALEDONIE
Localisation
Fonds IRD [F B010068149] ;
Nouméa
Identifiant IRD
fdi:010068149
