Titre :

Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles

Auteur(s) :

Le Quéré, Corinne [Auteur]
Tyndall Centre for Climate Change Research
Buitenhuis, Erik T. [Auteur]
Tyndall Centre for Climate Change Research
Moriarty, Róisín [Auteur]
Tyndall Centre for Climate Change Research
Alvain, Séverine [Auteur]
Université du Littoral Côte d'Opale [ULCO]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Aumont, Olivier [Auteur]
Nucleus for European Modeling of the Ocean [NEMO R&D]
Bopp, Laurent [Auteur]
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Chollet, Sophie [Auteur]
Enright, Clare [Auteur]
Franklin, Daniel J. [Auteur]
Geider, Richard J. [Auteur]
University of Essex
Harrison, Sandy P. [Auteur]
Department of Biological Sciences [North Ryde]
Hirst, Andrew G. [Auteur]
Larsen, Stuart [Auteur]
Legendre, Louis [Auteur]
Platt, Trevor [Auteur]
Prentice, Ian C. [Auteur]
Rivkin, Richard B. [Auteur]
Sailley, Sévrine [Auteur]
Plymouth Marine Laboratory [PML]
Sathyendranath, Shubha [Auteur]
Plymouth Marine Laboratory [PML]
Stephens, Nick [Auteur]
Vogt, Meike [Auteur]
Institute of Biogeochemistry and Pollutant Dynamics [ETH Zürich] [IBP]
Vallina, Sergio M. [Auteur]
Department of Marine Biology and Oceanography [Barcelone]

Titre de la revue :

Biogeosciences

Pagination :

4111 - 4133

Éditeur :

European Geosciences Union

Date de publication :

2016

ISSN :

1726-4170

Discipline(s) HAL :

Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]

Résumé en anglais : [en]

Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems ...
Lire la suite >Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Herewe present a global biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types (PFTs): six types of phytoplankton, three types of zooplankton, and heterotrophic procaryotes. We improved the representation of zooplanktondynamics in our model through (a) the explicit inclusion of large, slow-growing macrozooplankton (e.g. krill), and (b) the introduction of trophic cascades among the three zooplankton types. We use the model to quantitatively assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean high-nutrient lowchlorophyll (HNLC) region during summer. When model simulations do not include macrozooplankton grazing explicitly, they systematically overestimate Southern Ocean chlorophyll biomass during the summer, even when thereis no iron deposition from dust. When model simulations include a slow-growing macrozooplankton and trophic cascades among three zooplankton types, the high-chlorophyll summer bias in the Southern Ocean HNLC region largely disappears. Our model results suggest that the observed lowphytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean zooplankton community, despite iron limitation of phytoplankton community growth rates. This result has implications for the representation of global biogeochemicalcycles in models as zooplankton faecal pellets sink rapidly and partly control the carbon export to the intermediate and deep ocean.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Projet Européen :

Earth system Model Bias Reduction and assessing Abrupt Climate change

Collections :

• Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL